WorldWideScience

Sample records for arch dams

  1. 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.

  2. 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.

  3. Mechanical effects of excavation rebound of arch dam bedrock and better concreting time of dam body

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In high ground stress zone, rebound deformation of excavation of arch dam bedrock has a significant impact on the structural behavior, design and construction of arch dam. Based on the analysis of mechanical effects of excavation rebound, with both stress and deformation as two constraint conditions and deformation modulus as a controlling condition, the method to determine a better concreting time of dam body was put forward. All of these play an important guiding role in the excavation of dam bedrock and the construction of dam body.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Long-term dam safety monitoring of Punt dal Gall arch dam in Switzerland

    Institute of Scientific and Technical Information of China (English)

    M.WIELAND[1; G.F.KIRCHEN[2

    2012-01-01

    The 130 m high Punt dal Gall dam is located at the Swiss-Italian border in the South-eastern part of Switzerland and was completed in 1969.The dam is founded on highly folded and partially crushed dolomite and limestone formations.A grout curtain with an area of 120,000 m 2 was provided for controlling seepage.For the monitoring of the dam deformations five inverted pendulums were installed in the dam and three in the rock foundation of the right abutment outside of the dam.For a seasonal water level fluctuation in the reservoir of about 60 m the maximum amplitude of the radial displacement is 25 mm,which includes both the effects of the water load and temperature effects.Furthermore a comprehensive geodetic network was established,57 joint meters were installed and cracks in the crest gallery are monitored by crack meters.There are also thermometers,piezometers and rocmeters.Springs at the left and right banks of the dam are monitored and chemical analyses of the seepage water and springs are performed regularly.The dam is equipped with strong motion instruments and several near-field earthquakes have been recorded in the past.The paper describes the long-term safety monitoring of this 42 years old arch dam.A short description of the Swiss practice in dam safety monitoring and emergency planning is also given.

  11. 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.

  12. Collapse Modeling of a Masonry Arch Dam Using the Cohesive Interface Elements

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    Jianwen Pan

    2015-01-01

    Full Text Available A finite element (FE approach with zero-thickness cohesive interface elements is presented to simulate collapse of continuum structures. The element removal technique merged with the general contact algorithm is adapted in the FE approach to achieve modeling for a transition from continua to discontinua, that is, fracture, fragmentation, and collapse. Collapse process of Meihua masonry arch dam, which is a famous disaster in dam engineering in China, is simulated and the failure mechanism is studied. The collapse process obtained from the presented procedure coincides with the field observation after the dam failure. The failure of Meihua arch dam can be attributed to reducing shear strength of the peripheral joint between the dam body and the concrete pedestal by daubing a layer of asphalt there. With low sliding resistance strength, the masonry dam body may slide upwards along the peripheral joint under hydrostatic pressure, leading to weakening of the arch action, fracturing, and final collapse of the dam.

  13. 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.

  14. Crucial technologies in High the design of Xiluodu Super Arch Dam

    Institute of Scientific and Technical Information of China (English)

    Wang Renkun

    2012-01-01

    Some super high arch dams ( SHADs), like Xiluodu Arch Dam, after their heights reaching the magnitude of 300 m, confront lots of technical challenges in design and construction. Several crucial technologies of 6 SHADs will be reviewed and discussed in this and consecutive papers, including Xiluodu, Jinping I in China, Baktiary in Iran, ete. , on the topics of the research method, criterion for evaluation and engineering application of dam safety analysis and evaluation, reasonable dam base interface, dam shape optimization, comprehensive treatments of complex foundation, anti-seismic engineering, dam construction material, concrete placement and temperature control, instrumentation and monitoring of dam operation, etc. This paper will mainly focus on the overall safety of SHADs, reasonable dam base interface analysis and evaluation and their engineering application.

  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. 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.

  17. 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.

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

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    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.

  19. 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.

  20. 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.

  1. Mathematical modeling and numerical analysis of thermal distribution in arch dams considering solar radiation effect.

    Science.gov (United States)

    Mirzabozorg, H; Hariri-Ardebili, M A; Shirkhan, M; Seyed-Kolbadi, S M

    2014-01-01

    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.

  2. Variable-intercept panel model for deformation zoning of a super-high arch dam.

    Science.gov (United States)

    Shi, Zhongwen; Gu, Chongshi; Qin, Dong

    2016-01-01

    This study determines dam deformation similarity indexes based on an analysis of deformation zoning features and panel data clustering theory, with comprehensive consideration to the actual deformation law of super-high arch dams and the spatial-temporal features of dam deformation. Measurement methods of these indexes are studied. Based on the established deformation similarity criteria, the principle used to determine the number of dam deformation zones is constructed through entropy weight method. This study proposes the deformation zoning method for super-high arch dams and the implementation steps, analyzes the effect of special influencing factors of different dam zones on the deformation, introduces dummy variables that represent the special effect of dam deformation, and establishes a variable-intercept panel model for deformation zoning of super-high arch dams. Based on different patterns of the special effect in the variable-intercept panel model, two panel analysis models were established to monitor fixed and random effects of dam deformation. Hausman test method of model selection and model effectiveness assessment method are discussed. Finally, the effectiveness of established models is verified through a case study.

  3. Earthquake response of concrete arch dams with layered rock foundation in time domain with a case study of an arch dam in Iran

    Energy Technology Data Exchange (ETDEWEB)

    Barikani, A. [Tabriz Univ., Tehran (Iran, Islamic Republic of). Dept. of Civil Engineering; Hashemiravan, M. [Varamin Azad Univ., Tehran (Iran, Islamic Republic of). Dept. of Civil Engineering

    2006-07-01

    This study examined the dynamic behaviour of an arch dam and the interactions between the dam and its layered rock foundation. The seismic response of the Amir Kabir dam located in Iran was investigated using a 3-D finite element model. The rock foundation of the dam was divided into 3 areas: high resistance rock, medium resistance rock, and low resistance rock. The hydrodynamic effects of water were modelled using an added mass method with concentrate masses in nodes of elements on the upstream face of the dam body. Earthquake response of the dam was demonstrated using a time history of displacement at the dam crest, contours of maximum tensile stresses, and maximum pressure stresses on the upstream and downstream face of the dam. The study also examined issues concerning tensile cracks that occurred as a result of an actual earthquake. Results showed that the maximum tensile stress in the upstream face of the dam was 2.5 times more than allowable limits for tensile stress in concrete. The maximum pressure stress was lower than allowable limits. A comparison between the time history of the principal stresses at different points of the dam demonstrated that maximum tensile stress occurred in the middle of the dam. However pressure was highest near the foundation level. Results showed that the tensile cracks in the dam crest area were caused by the excessive amounts of tensile stress. It was also concluded that the earthquake used in the study was in the design basis earthquake (DBE) category, with a return period of approximately 200 years. 7 refs., 5 tabs., 10 figs.

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

    Science.gov (United States)

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

    2011-10-01

    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 305 m is analyzed using the seismic records of the Wenchuan Earthquake in 2008. Numerical results 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.

  5. Construction Simulation and Real-Time Control for High Arch Dam

    Institute of Scientific and Technical Information of China (English)

    ZHONG Denghua; REN Bingyu; WU Kangxin

    2008-01-01

    A method of combining dynamic simulation with real-time control was proposed to fit the randomness and uncertainty in the high arch dam construction process. The mathematical logic model of high arch dam construction process was established. By combining dynamic con-struction simulation with schedule analysis, the process of construction schedule forecasting and analysis based on dynamic simulation was studied. The process of real-time schedule control was constructed and some measures for dynamic adjustment and control of construction schedule were provided. A system developed with the method is utilized in a being constructed hydroelectric pro-ject located at the Yellow River in northwest China, which can make the pouring plan of the dam in the next stage (a month, cluarter or year) to guide the practical construction. The application result shows that the system provides an effective technical support for the construction and manage-ment of the dam.

  6. Bin-objective shape optimization based on linear programming model of arch dam

    Institute of Scientific and Technical Information of China (English)

    JIN Hai; LIN Gao; YANG Ming-sheng

    2007-01-01

    Bin-objective shape optimization of arch dam based on linear programming model is discussed to minimize both dam volume and maximal tensile stress. The importance of weight coefficient of the above two objectives is chosen according to the value of importance ratio. The influence of weight coefficient to the optimization result is discussed in detail and the numerical example shows that both the model and method proposed is doable.

  7. Ant Colony Optimization Analysis on Overall Stability of High Arch Dam Basis of Field Monitoring

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    Peng Lin

    2014-01-01

    Full Text Available A dam ant colony optimization (D-ACO analysis of the overall stability of high arch dams on complicated foundations is presented in this paper. A modified ant colony optimization (ACO model is proposed for obtaining dam concrete and rock mechanical parameters. A typical dam parameter feedback problem is proposed for nonlinear back-analysis numerical model based on field monitoring deformation and ACO. The basic principle of the proposed model is the establishment of the objective function of optimizing real concrete and rock mechanical parameter. The feedback analysis is then implemented with a modified ant colony algorithm. The algorithm performance is satisfactory, and the accuracy is verified. The m groups of feedback parameters, used to run a nonlinear FEM code, and the displacement and stress distribution are discussed. A feedback analysis of the deformation of the Lijiaxia arch dam and based on the modified ant colony optimization method is also conducted. By considering various material parameters obtained using different analysis methods, comparative analyses were conducted on dam displacements, stress distribution characteristics, and overall dam stability. The comparison results show that the proposal model can effectively solve for feedback multiple parameters of dam concrete and rock material and basically satisfy assessment requirements for geotechnical structural engineering discipline.

  8. Ant colony optimization analysis on overall stability of high arch dam basis of field monitoring.

    Science.gov (United States)

    Lin, Peng; Liu, Xiaoli; Chen, Hong-Xin; Kim, Jinxie

    2014-01-01

    A dam ant colony optimization (D-ACO) analysis of the overall stability of high arch dams on complicated foundations is presented in this paper. A modified ant colony optimization (ACO) model is proposed for obtaining dam concrete and rock mechanical parameters. A typical dam parameter feedback problem is proposed for nonlinear back-analysis numerical model based on field monitoring deformation and ACO. The basic principle of the proposed model is the establishment of the objective function of optimizing real concrete and rock mechanical parameter. The feedback analysis is then implemented with a modified ant colony algorithm. The algorithm performance is satisfactory, and the accuracy is verified. The m groups of feedback parameters, used to run a nonlinear FEM code, and the displacement and stress distribution are discussed. A feedback analysis of the deformation of the Lijiaxia arch dam and based on the modified ant colony optimization method is also conducted. By considering various material parameters obtained using different analysis methods, comparative analyses were conducted on dam displacements, stress distribution characteristics, and overall dam stability. The comparison results show that the proposal model can effectively solve for feedback multiple parameters of dam concrete and rock material and basically satisfy assessment requirements for geotechnical structural engineering discipline.

  9. Seismic response of arch dams considering infinite radiation damping and joint opening effects

    Institute of Scientific and Technical Information of China (English)

    刘新佳; 徐艳杰; 王光纶; 张楚汉

    2002-01-01

    Effects of two important factors on earthquake response of high arch dams are considered and combined into oneprogram. These factors are: effects of radiation damping of the infinite canyon and local non-linearity of the contraction jointopening between the dam monoliths. For modeling of rock canyon, the discrete parameters are obtained based on a curve fitting,thus allowing the nonlinear dam system to be solved in the time domain. The earthquake uniform free-field input at thedam-canyon interface is used. An engineering example is given to demonstrate the significant effects of the radiation dampingon the structure response.

  10. Numerical dynamic analysis of Chiti single arch dam related to hydroelectric power generation

    Energy Technology Data Exchange (ETDEWEB)

    Abbasi, H. [Islamic Azad Univ., Tehran (Iran, Islamic Republic of); Hosseini, Y.; Jalaly, H. [Ab-Niru Consulting Engineers, Tehran (Iran, Islamic Republic of); Aghajani, K. [Elam Univ., Elam (Iran, Islamic Republic of)

    2006-07-01

    The Chiti dam is a single arch hydroelectric power generation dam located on the Taloogh River in Iran. This paper provided details of the response spectrum method used to design the optimal load conditions and slope of the dam in relation to earthquake protection. The amount of horizontal earthquake acceleration at the dam site was determined based on local calculations of scenarios of an operating basis earthquake (OBE), a maximum design earthquake (MDE) and a maximum credible earthquake (MCE). The response spectrum was defined with 5 per cent damping as the basis of the earthquake calculation. Hydrodynamic pressure was applied in loadings and the dam was analyzed with and without the effect of hydrodynamic pressure. The compressive strength of the concrete was considered as 28 MPa, and the properties of bed rock were determined on geotechnical and geological studies. Hydrodynamic pressure was calculated based on upstream water levels in the reservoir of the arch dam and applied to the model as added mass. The model also considered the weight of the dam body, uplift pressure, and heat changes in stable conditions. The hydrodynamic pressure of water was applied as additional mass to the upstream face of the arch dam. The additional mass was determined based on dam height. The dynamic analysis of the dam was performed using response spectrum data. The model analysis was performed with and without the effect of hydrodynamic pressure. The 3-D model of the dam body was made using the ANSYS finite element program which combined the response spectrum method with temperature load, uplift pressure and water pressure parameters. Results showed that the maximum displacement of the dam body for the various earthquake levels measured was 11.6, 14, and 15.6 mm respectively. The response spectrum analysis performed with hydrodynamic pressure showed displacement values of 22.4, 24.8, and 26.4 mm. Stress and strain values obtained by the model were within allowable amount for

  11. Analysis of foundation sliding of an arch dam considering the hydromechanical behavior

    Institute of Scientific and Technical Information of China (English)

    Maria; Luísa; Braga; FARINHA; José; Vieira; de; LEMOS; Emanuel; MARANHA; DAS; NEVES

    2012-01-01

    This paper presents the application of a methodology which can be used to assess arch dam foundation stability,using the discrete element method (DEM) and the code 3DEC.A global three-dimensional model of a dam foundation was developed,in which some discontinuities were simulated and both the grout and drainage curtains were represented.The model,calibrated taking into account recorded data,was used to carry out nonlinear mechanical analysis.The same model was employed to perform a hydraulic analysis,based on equivalent continuum concepts,which allowed the water pressure pattern within the foundation to be obtained.These water pressures were applied on discontinuities involved in the possible sliding mechanism along the dam/foundation interface,and the safety of the dam/foundation system was evaluated using a process of reduction of strength characteristics,with the aim of calculating the minimum safety factors that ensure stability.Results were compared with those obtained with the usual bi-linear uplift pressure distribution at the base of the dam,commonly used in concrete dam design.The relevance of carrying out hydraulic analysis in arch dam foundation failure studies is highlighted.

  12. Statistical Analysis and Calculation Model of Flexibility Coefficient of Low- and Medium-Sized Arch Dam

    Directory of Open Access Journals (Sweden)

    Su Huaizhi

    2012-01-01

    Full Text Available The flexibility coefficient is popularly used to implement the macroevaluation of shape, safety, and economy for arch dam. However, the description of flexibility coefficient has not drawn a widely consensus all the time. Based on a large number of relative instance data, the relationship between influencing factor and flexibility coefficient is analyzed by means of partial least-squares regression. The partial least-squares regression equation of flexibility coefficient in certain height range between 30 m and 70 m is established. Regressive precision and equation stability are further investigated. The analytical model of statistical flexibility coefficient is provided. The flexibility coefficient criterion is determined preliminarily to evaluate the shape of low- and medium-sized arch dam. A case study is finally presented to illustrate the potential engineering application. According to the analysis result of partial least-squares regression, it is shown that there is strong relationship between flexibility coefficient and average thickness of dam, thickness-height ratio of crown cantilever, arc height ratio, and dam height, but the effect of rise-span ratio is little relatively. The considered factors in the proposed model are more comprehensive, and the applied scope is clearer than that of the traditional calculation methods. It is more suitable for the analogy analysis in engineering design and the safety evaluation for arch dam.

  13. Ambient modal testing of a double-arch dam: the experimental campaign and model updating

    Science.gov (United States)

    García-Palacios, Jaime H.; Soria, José M.; Díaz, Iván M.; Tirado-Andrés, Francisco

    2016-09-01

    A finite element model updating of a double-curvature-arch dam (La Tajera, Spain) is carried out hereof using the modal parameters obtained from an operational modal analysis. That is, the system modal dampings, natural frequencies and mode shapes have been identified using output-only identification techniques under environmental loads (wind, vehicles). A finite element model of the dam-reservoir-foundation system was initially created. Then, a testing campaing was then carried out from the most significant test points using high-sensitivity accelerometers wirelessly synchronized. Afterwards, the model updating of the initial model was done using a Monte Carlo based approach in order to match it to the recorded dynamic behaviour. The updated model may be used within a structural health monitoring system for damage detection or, for instance, for the analysis of the seismic response of the arch dam- reservoir-foundation coupled system.

  14. Determining the Optimal Placement of Sensors on a Concrete Arch Dam Using a Quantum Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Kai Zhu

    2016-01-01

    Full Text Available Structural modal identification has become increasingly important in health monitoring, fault diagnosis, vibration control, and dynamic analysis of engineering structures in recent years. Based on an analysis of traditional optimization algorithms, this paper proposes a novel sensor optimization criterion that combines the effective independence (EFI method with the modal strain energy (MSE method. Considering the complex structure and enormous degrees of freedom (DOFs of modern concrete arch dam, a quantum genetic algorithm (QGA is used to optimize the corresponding sensor network on the upstream surface of a dam. Finally, this study uses a specific concrete arch dam as an example and determines the optimal sensor placement using the proposed method. By comparing the results with the traditional optimization methods, the proposed method is shown to maximize the spatial intersection angle among the modal vectors of sensor network and can effectively resist ambient perturbations, which will make the identified modal parameters more precise.

  15. On the obstacles and way to assess the seismic catastrophe for high arch dams

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    To prevent possible seismic catastrophe,naturally,its assessment is deeply concerned over in China as a series of arch dams of about 300 m high will be constructed in the severe seismic regions.In this paper the major obstacles to the seismic catastrophe assessment of high arch dams which focused on clearly defining the Maximum Credible Earthquake (MCE) and reasonably selecting its site-specific seismic input parameters as well as quantitatively evaluating the limit state of dam-breach for designers are emphasized.Some breakthrough progress with pending problems is presented,such as to adopt more reasonable seismic input parameters based on seismic hazard evaluation of dam site; to develop model and method more fit in with the reality for non-linear seismic analysis of dam-foundation-reservoir system.The ideals of further improvement both in evaluating the MCE and defining the quantitative index of its performance objective are discussed,including how to use semi-empirical method of simulating strong ground motion near fault,how to solve the long-standing problem of stress singularity at dam heel,and how to investigate dynamic behaviors of fully-graded damconcrete through dynamic tests and 3-dimensional meso-mechanics analysis checked by CT technique.

  16. An Interactive Tool for Automatic Predimensioning and Numerical Modeling of Arch Dams

    Directory of Open Access Journals (Sweden)

    D. J. Vicente

    2017-01-01

    Full Text Available The construction of double-curvature arch dams is an attractive solution from an economic viewpoint due to the reduced volume of concrete necessary for their construction as compared to conventional gravity dams. Due to their complex geometry, many criteria have arisen for their design. However, the most widespread methods are based on recommendations of traditional technical documents without taking into account the possibilities of computer-aided design. In this paper, an innovative software tool to design FEM models of double-curvature arch dams is presented. Several capabilities are allowed: simplified geometry creation (interesting for academic purposes, preliminary geometrical design, high-detailed model construction, and stochastic calculation performance (introducing uncertainty associated with material properties and other parameters. This paper specially focuses on geometrical issues describing the functionalities of the tool and the fundamentals of the design procedure with regard to the following aspects: topography, reference cylinder, excavation depth, crown cantilever thickness and curvature, horizontal arch curvature, excavation and concrete mass volume, and additional elements such as joints or spillways. Examples of application on two Spanish dams are presented and the results obtained analyzed.

  17. Study on multi-scheme analysis and evaluation method for concrete sequence placement of high arch dam

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    A complete scheme for solving the key scientific problems of how to make concrete sequence placement scheme of high arch dam reasonable and feasible and how to meet the need of construction process was presented.First,based on a coupling analysis of concrete sequence placement system of high arch dam,a mathematical model considering complex construction constraints was established.Second,a multi-scheme computational analysis method for concrete sequence placement of high arch dam was proposed based on dynamic simulation.Third,a multi-scheme evaluation method for concrete sequence placement was put forward based on analytic hierarchy process.Fourth,feedback guidance for progress control and management in the high arch dam construction process was proposed.Finally,these methods were applied to a practical project to show that the methods can analyze and evaluate multi-scheme for concrete sequence placement of high arch dam effectively,optimize the process of dam concrete sequence placement,and recommend engineering measures.These methods provide new theoretical principles and technical measures for real-time progress control in the high arch dam construction.

  18. The traps behind the failure of Malpasset arch dam, France, in 1959

    Institute of Scientific and Technical Information of China (English)

    Pierre Duffaut

    2013-01-01

    The case of the Malpasset arch dam failure in 1959 has been widely exposed in scientific and technical forums and papers. The focus here is on the many traps which have confused the whole chain of bodies and persons involved, owner, designer, geologist, contractor, up to the state management officers. When the first traps were hidden inside geology, many more appeared, as well geotechnical, technical, fortuitous, and administrative. In addition to such factual factors, human and organizational factors may be today easily identified, when none of them was yet suspected. Both dam safety and rock mechanics benefited from the studies done since the Malpasset case, most of them within one decade.

  19. Research on analysis method for temperature control information of high arch dam construction

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Temperature control,which is directly responsible for the project quality and progress,plays an important role in high arch dam construction.How to discover the rules from a large amount of temperature control information collected in order to guide the adjustment of temperature control measures to prevent cracks on site is the key scientific problem.In this paper,a mathematic logical model was built firstly by means of a coupling analysis of temperature control system decomposition and coordination for high arch dam.Then,an analysis method for temperature control information was presented based on data mining technology.Furthermore,the data warehouse of temperature control was designed,and the artificial neural network forecasting model for the highest temperature of concrete was also developed.Finally,these methods were applied to a practical project. The result showed that the efficiency and precision of temperature control was improved,and rationality and scientificity of management and decision-making were strengthened.All of these researches provided an advanced analysis method for temperature control in the high arch dam construction process.

  20. Effects of shear keys on nonlinear seismic responses of an arch-gravity dam

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    In the paper,the added tangential nonlinear springs are introduced to represent the effects of one-way and two-way shear keys. The added tangential stiffness coefficient is relative to the joint opening and the relative tangential movement and determined numerically by using a refined model of shear keys.The user subroutine of nonlinear spring elements has been implemented into ABAQUS program.The seismic responses of an arch-gravity dam are mainly examined.It is shown by the results that a significant increase of about 17%-30%in joint opening can be observed for the dam with one-way shear keys;the two-way shear keys are beneficial to restrain the sliding displacement along both the radial and vertical directions,whereas the one-way shear keys mainly restrain the displacement along the radial direction;for the dam with shear keys,the maximum arch stress is increased,the cantilever stress is reduced,and the location of the maximum cantilever stress is also moved from the dam heel to the midheight of the cantilever.

  1. Deformation Monitoring of Geomechanical Model Test and Its Application in Overall Stability Analysis of a High Arch Dam

    Directory of Open Access Journals (Sweden)

    Baoquan Yang

    2015-01-01

    Full Text Available Geomechanical model testing is an important method for studying the overall stability of high arch dams. The main task of a geomechanical model test is deformation monitoring. Currently, many types of deformation instruments are used for deformation monitoring of dam models, which provide valuable information on the deformation characteristics of the prototype dams. However, further investigation is required for assessing the overall stability of high arch dams through analyzing deformation monitoring data. First, a relationship for assessing the stability of dams is established based on the comprehensive model test method. Second, a stability evaluation system is presented based on the deformation monitoring data, together with the relationships between the deformation and overloading coefficient. Finally, the comprehensive model test method is applied to study the overall stability of the Jinping-I high arch dam. A three-dimensional destructive test of the geomechanical model dam is conducted under reinforced foundation conditions. The deformation characteristics and failure mechanisms of the dam abutments and foundation were investigated. The test results indicate that the stability safety factors of the dam abutments and foundation range from 5.2 to 6.0. These research results provide an important scientific insight into the design, construction, and operation stages of this project.

  2. Simulation of influence of multi-defects on long-term working performance of high arch dam

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    As an integrated structure,an arch dam is assumed to bear loads in its design consideration.However,multi-defects,such as cracks and the opening of transverse joints,are unavoidable during construction and operation.Multi-defects will reduce the structural integrity and stiffness of the dam and affect its working performance and degree of safety.In the current paper,a numerical model of defects and a simulation method of a high arch dam are introduced.The Chencun arch dam is analyzed as a case study.An entire course simulation analysis of the Chencun arch dam from construction to operation is carried out,through which the opening of the transverse and longitudinal joints,formation of cracks,and their influence on deformation and stress of the dam are studied.According to the results of the analysis,appropriate measures should be adopted to prevent the development of cracks,and observation should be strengthened for a more timely discovery of risks.

  3. Seismic damage-cracking analysis of arch dams using different earthquake input mechanisms

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In this study, a nonlinear model is presented for analysis of damage-cracking behavior in arch dams during strong earthquakes using different seismic input mechanisms. The nonlinear system includes a plastic-damage model for cyclic loading of concrete considering strain softening and a contact boundary model of contraction joint opening. Two different earthquake input mechanisms are used for comparison, including massless foundation input model and viscous-spring boundary model considering radiation damping due to infinite canyon. The results demonstrate that effects of seismic input mechanism and radiation damping on nonlinear response and damage-cracking of the dam are significant. Compared with the results of using massless foundation input model, the damage-cracking region and contraction joint opening are substantially reduced when using viscous-spring boundary model to take into account radiation damping. However, if the damping ratio of the dam is artificially increased to about 10%―15% for massless foundation input model, the joint opening and damage-cracking of the dam are comparable to the results obtained from the viscous-spring boundary model.

  4. Fracture Analysis of Brittle Materials Based on Nonlinear FEM and Application in Arch Dam with Fractures

    Directory of Open Access Journals (Sweden)

    Yuanwei Pan

    2013-01-01

    Full Text Available Current fracture analysis models based on fracture mechanics or continuum damage mechanics are still limited in the application to three-dimensional structure. Based on deformation reinforcement theory coming from elastoperfect plastic theory, unbalanced force is proposed to predict initiation and propagation of cracks. Unbalanced force is the driving force of time-dependent deformation according to Perzyna’s viscoplasticity theory. It is also related to the damage driving force in viscoplastic damage model. The distribution of unbalanced force indicates cracks initiation area, while its direction predicts possible cracks propagation path. Uniaxial compression test of precrack specimen is performed as verification to this method. The trend and distribution of cracks are in good agreement with numerical results, proving that unbalanced force is feasible and effective for fracture analysis. The method is applied in fracture analysis of Xiaowan high arch dam, which is subjected to some cracks in dam due to the temperature control program. The results show that the deformation and stress of cracks and the stress characteristics of dam are insensitive to grouting of cracks. The existing cracks are stable and dam heel is still the most possible cracking position.

  5. Displacements Prediction in Double-Arch Dam Rock Abutment Using SPSS Software Based on Extensometer Readings Case study: Karun 4 Concrete Dam, Iran

    Directory of Open Access Journals (Sweden)

    Hadi kamali Bandpey

    2012-11-01

    Full Text Available In this study we present a method for Displacements Prediction in Double-Arch Dam Rock Abutment Using SPSS Software Based on Extensometer Readings. Displacement in dams is the most tangible and important parameter which could be crucial in their safety. Different elevation displacements are yielded by various loadings and the thrust force imposed on foundation and abutment. Most concrete dams are constructed on stone foundations. Displacements in foundation and abutment are measured by extensometers. Karun 4 Concrete dam is designed with 11 galleries, from elevation 1016 to 802 m, in the order from top elevation (dam crest elevation 1032 to the bottom elevation (dam foundation elevation 806 within the dam body. As a whole, 19 extensometers in the left bank, 17 in the right, and one more in the middle are implemented in the dam. Karun 4 dam has already been impounded with water up to the elevation 1003. Displacements in Karun 4 are recorded by extensometers whence water was leveled in 7 elevations 943.68, 953.36, 973.55, 983.28, 993.17, 1003.13. In this study, using SPSS we have tried to predict the displacements for a situation in which water will be elevated to the elevations 1013, 1023, 1032 in the future for elevations which are equipped with anchor. The most predicted displacement pertaining to the left bank when water was leveled to the elevation 1013, was 3.65 mms by R2 = 0.9997 for the implemented anchor. Proceeding further, as water is leveled to the elevations 1023 and 1033, the most predicted displacement respectively would be 4.31 and 5.66 by R2 = 0.9941; and is related to the anchor implemented in the elevation 936.05. The most predicted displacement for the right bank is 5.9397, 7.2347 and 8.6877 mms by R2 = 0.9995 for the elevation 888.128 m.

  6. 七里坝水库除险加固拱坝应力分析%Stress analysis of risk removal reinforcement arch dam in Qiliba Reservoir

    Institute of Scientific and Technical Information of China (English)

    李太军

    2015-01-01

    Qiliba Reservoir is located in mountain valley area,which has been operated for many years and belongs to dangerous reservoir.The arch dam belongs to thickened single arch dam on the downstream face.The dam body have transverse cracks and horizontal cracks.In the paper,arch dam stress is comparatively analyzed and studied.The reinforcement treatment plan of arch gravity dam is proposed.The conclusion of stable and safe arch dam after risk removal and reinforcement is obtained,and the operation results show that the dam is stable with safe operation.%七里坝水库处于高山峡谷地区,为运行多年的病险水库,拱坝为下游面加厚的单曲拱坝,坝体存在横向裂缝和水平裂缝,本文通过对拱坝应力进行对比分析研究,提出了拱型重力坝加固处理方案,得出了除险加固后拱坝稳定安全的结论,运行结果表明,大坝稳定、运行安全。

  7. Parametric modeling of arch dam based on Excel-VBA and APDL%基于Excel-VBA与APDL的拱坝参数化建模方法

    Institute of Scientific and Technical Information of China (English)

    周强

    2015-01-01

    Modeling of arch dam is growing more and more difficult as its complex shape. To get the re-quired coordinates of arch dam modeling, this paper does secondary development of Excel by VBA. And acquired coordinates could generate executable APDL code, which would make establishing double-cur-vature arch dam model more quickly and efficiently. It could save a lot of time for the next simulation analysis and calculation of arch dam. The result shows that the parameterized modeling of arch dam be-comes more convenient and accurate by the method combining Excel-VBA and APDL.%由于拱坝体形较为复杂,拱坝建模难度较大.笔者利用VBA对Excel进行二次开发,得出拱坝建模中所需的点坐标.根据这些点坐标生成ANSYS中可执行的APDL代码,快捷高效地建立了双曲拱坝模型,为此后的拱坝仿真计算创造了条件.实例表明,Excel-VBA与APDL的结合使用,可以使ANSYS中拱坝的参数化建模更为方便和准确.

  8. Seismic damage analysis of the outlet piers of arch dams using the finite element sub-model method

    Science.gov (United States)

    Song, Liangfeng; Wu, Mingxin; Wang, Jinting; Xu, Yanjie

    2016-09-01

    This study aims to analyze seismic damage of reinforced outlet piers of arch dams by the nonlinear finite element (FE) sub-model method. First, the dam-foundation system is modeled and analyzed, in which the effects of infinite foundation, contraction joints, and nonlinear concrete are taken into account. The detailed structures of the outlet pier are then simulated with a refined FE model in the sub-model analysis. In this way the damage mechanism of the plain (unreinforced) outlet pier is analyzed, and the effects of two reinforcement measures (i.e., post-tensioned anchor cables and reinforcing bar) on the dynamic damage to the outlet pier are investigated comprehensively. Results show that the plain pier is damaged severely by strong earthquakes while implementation of post-tensioned anchor cables strengthens the pier effectively. In addition, radiation damping strongly alleviates seismic damage to the piers.

  9. Calculation Model of Equivalent Strength for Induced Crack Based on Double-K Fracture Theory and Its Optimizing Setting in RCC Arch Dam

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiaogang; SONG Yupu; WU Zhimin

    2005-01-01

    By means of fracture testing on roller-compacted concrete (RCC) three-point bending beams with two different specimen sizes, the P-CMOD complete curve for RCC was gained. Furthermore, by applying double-K fracture theory, KiniⅠC,KunⅠC, as well as the critical effective crack length and the critical crack tip opening displacement, were evaluated. Based on the double-K fracture parameters above, the calculation model of equivalent strength for induced crack was established, thus the calculation method on its initiation, stable propagation and unstable fracture was ascertained. Moreover, the finite element simulation analysis of stress field in ShaPai arch dam and the on-site observational splaying points of induced crack at different altitudes validated the reliability of the model. Finally, crack inducer's optimal setting in RCC arch dam was studied. It improves the design level of induced crack in RCC arch dam and satisfies the necessity of engineering practice.

  10. Ambient Vibration Tests of an Arch Dam with Different Reservoir Water Levels: Experimental Results and Comparison with Finite Element Modelling

    Directory of Open Access Journals (Sweden)

    Sergio Vincenzo Calcina

    2014-01-01

    Full Text Available This paper deals with the ambient vibration tests performed in an arch dam in two different working conditions in order to assess the effect produced by two different reservoir water levels on the structural vibration properties. The study consists of an experimental part and a numerical part. The experimental tests were carried out in two different periods of the year, at the beginning of autumn (October 2012 and at the end of winter (March 2013, respectively. The measurements were performed using a fast technique based on asynchronous records of microtremor time-series. In-contact single-station measurements were done by means of one single high resolution triaxial tromometer and two low-frequency seismometers, placed in different points of the structure. The Standard Spectral Ratio method has been used to evaluate the natural frequencies of vibration of the structure. A 3D finite element model of the arch dam-reservoir-foundation system has been developed to verify analytically determined vibration properties, such as natural frequencies and mode shapes, and their changes linked to water level with the experimental results.

  11. 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.

  12. Key technologies for the construction of the Xiluodu high arch dam on the Jinsha River in the development of hydropower in western China

    Institute of Scientific and Technical Information of China (English)

    Lu Youmei; Fan Qixiang; Zhou Shaowu; Li Bingfeng; Li Wenwei

    2012-01-01

    Hydropower development in China is concentrated in the country' s western regions. Among all the rivers in China, the lower course of the Jinsha River contains the richest hydro-energy resource, and therefore, 4 mammoth hy- dropower plants are under construction on this particular section of the river at Wudongde, Baihetan, Xiluodu, and Xiangjiaba. The water-blocking structures of the hydropower facilities at Wudongde, Baihetan and Xiluodu are all arch dams of around 300 m high. In view of changes in the geological conditions at the foundation of the Xiluodu dam on the riverbed after excavation started, the designs of expanding foundation surface excavation and dovetailing the dam body and foundation rock on both upstream and downstream sides were introduced, allowing the arch dam and foundation to fit each other and improving the stress conditions of the dam body and foundation. By dividing the dam body into various concrete sections, the dynamic properties of concrete were adequately adjusted to the distribution of stress in the dam body. In addition, the use of the most optimal concrete material and mixture ratio allowed thermodynamics of concrete to satisfy the requirements of the strength, durability, temperature control and crack prevention of the concrete. Moreover, rigorous temperature control measures were introduced to prevent harmful cracking, thus enhancing the integrity of the arch dam. Furthermore, sophisticated construction machinery, scientific testing methods, and sound construction tech- niques were employed to ensure the uniformity and reliability of concrete placement. The "Digital Dam" for the Xiluodu project, which is based on the theory of total life cycle, has supplied strong support for construction process control and decision-making.

  13. Development Aad Application on Stability Analysis of Abutment of ARCH DAM%拱坝坝肩稳定性分析程序开发与应用

    Institute of Scientific and Technical Information of China (English)

    赖雅琳

    2011-01-01

    In order to resolve the problems of heavy workload and repetitive calculation on stability analysis of abutment of arch dam, the VBA language was used to develop the software of stability analysis of abutment of arch dam. The program includes two sections, one section of which is to create communication between VBA and EXCEL then extract data, and the other section of which is to realize interactive operation between VBA and AutoCAD to induce least stability safety factor. A certain arch dam was chosen in CAD map as case study and the least stability safety factor can be yielded by calculation. The results show that this program runs safely and steadily which design criteria.%采用VBA语言编程开发拱坝坝肩稳定分析程序.程序包括建立VBA与EXCEL通信并提取相关数据,VBA与CAD交互操作求最小稳定安全系数两部分.应用该系统时,用户只需要输入或选择程序默认参数数值,并在CAD地形图文件上选取若干实体,即可自动计算出对应高程的拱坝坝肩最小稳定安全系数.工程实例结果显示,程序运行安全可靠,符合设计标准.

  14. 瀑布沟大坝心墙拱效应分析%Arching effect analysis of core wall in Pubugou dam

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    Based on the previous definitions of arching effect coefficient, the formula of arching effect coefficient is improved. It is suggested that the arching effect coefficient should be the ratio of measured soil pressure and the sum of overlaying soil pressure and pore water pressure. Combining with the monitoring data of Pubugou dam, the arching effect of core wall is calculated by the improved formula of arch effect coefficient; and dynamical analysis of arching effect is made. Construction technology is the main factor affecting the arching effect coefficient of core wall during the construction. The arching effect coefficient is larger when the filled soil is 0-20 m above the instruments; and decreases with the rising of filled soil. The stress distribution of dam during construction plays an important role in initial water storage. During the impoundment, the arching effect coefficient of upstream side of the core wall shows inverse correlation with water level variation. The arching effect coefficient of upstream side is larger than that of downstream side at the same elevation and 0+001 m. The arching effect coefficient at 0+001 m shows positive correlation with water level variation, where gets the smallest arching effect coefficient. The arching effect coefficient of downstream side of core wall shows positive correlation with water level variation. The arching effect coefficient is larger than 100% on the contact surface between core wall and bed rock. There are three reasons for the above laws, such as wetting, seepage and hydraulic fracture; and the combined effect of the three results in stress variation in core wall.%  在总结前人提出的拱效应系数基础上,对拱效应系数的公式进行了改进,认为拱效应系数应该是实测土压力与上覆土压力和孔隙水压力之和的比值。结合瀑布沟大坝监测资料,用改进的拱效应系数计算公式对大坝心墙拱效应进行计算,并对心墙内拱效应进

  15. Evaluation of Groundwater Leakage into a Drainage Tunnel in Jinping-I Arch Dam Foundation in Southwestern China: A Case Study

    Science.gov (United States)

    Chen, Yi-Feng; Hong, Jia-Min; Zheng, Hua-Kang; Li, Yi; Hu, Ran; Zhou, Chuang-Bing

    2016-03-01

    The Jinping-I double-curvature arch dam, located in the middle reach of Yalong River and with a maximum height of 305 m, is the world's highest dam of this type that has been completed. Since the second stage of reservoir impounding, after which the reservoir water level was gradually raised by about 232 m, a significant amount of leakage was observed from the drainage holes drilled in the lowest drainage tunnel at the left bank abutment at an elevation of 1595 m a.s.l. (above sea level), with an observed maximum pressure of about 0.3 MPa. A number of investigations, including water quality analysis, digital borehole imaging, tunnel geological mapping, and in situ groundwater monitoring, were performed to examine the source of leaking, the groundwater flow paths, and the performance of the grouting curtains. By defining two objective functions using the in situ time series measurements of flow rate and hydraulic head, respectively, a multiobjective inverse modeling procedure was proposed to evaluate the permeability of the foundation rocks that was underestimated in the design stage. This procedure takes advantage of the orthogonal design, finite element forward modeling of the transient groundwater flow, artificial neural network, and non-dominated sorting genetic algorithm, hence significantly reducing the computational cost and improving the reliability of the inversed results. The geological structures that lead to the leakage were identified and the seepage flow behaviors in the dam foundation and the left bank abutment were assessed. Based on the field measurements and the inverse modeling results, the effects of the engineering treatments of the leakage event on the dam safety were analyzed. It has been demonstrated that the seepage control system is effective in lowering the groundwater level and limiting the amount of seepage in the dam foundation, and the leakage event does not pose a threat to the safety of the dam.

  16. 小湾高拱坝拱座稳定三维极限分析%Xiaowan High Arch Dam Abutment Stability 3- D Limit Analysis

    Institute of Scientific and Technical Information of China (English)

    陈祖煜; 汪小刚; 王剑

    2000-01-01

    小湾岩体存在两组垂直结构面和一组倾向河道的卸荷裂隙。拱座稳定存在着沿拱推力方向和重力方向组合的空间滑动模式。本文首先介绍了一个建立在塑性力学上限定理基础上的边坡稳定分析三维极限分析方法,并使用这一方法计算小湾拱座的稳定安全系数,获得比较符合实际的稳定分析成果。%There are two sets of vertical shearing planes and one set of relaxed fissures dipping towards the river course in the rock mass at the Xiaowan dam site. In terms of the arch abutment stability the spatial sliding patterns created by their combination along the arch thrust and gravity directions should be considered. This paper gives a presentation of the 3- D limit analysis method developed on the basis of the plasticity mechanics upper limit theorem for slope stability analysis, and of the stability safety factor of the Xiaowan arch abutment calculated using this method which could give stability analysis results conforming to the actual conditions.

  17. 贵州省白马山水库混凝土砌石拱坝优化设计%Research on Optimization Design of Baima Mountain Reservoir Concrete Stone-laying Arch Dam of Guizhou Province

    Institute of Scientific and Technical Information of China (English)

    成克雄; 谭剑波

    2014-01-01

    贵州省白马山水库大坝是一座混凝土砌毛石重力单曲拱坝,最大坝高48 m,采用ADAO拱坝分析与优化软件,对坝体结构、应力变形、坝肩稳定性等进行了分析。调整了设计方案,使坝体设计方案满足SL25-2006和SL282-2003等技术规范要求。%Baima mountain reservoir dam of Guizhou province is a single concrete gravity arch dam with a maximum height of 48 meters, which built by laying stones rubble by masonry technique. This article analyzes the dam body structure, stress deformation and dam abutment stability by adopting analogy method and combining ADAO arch dam analysis and optimization software, it adjusts the design scheme of dam body to satisfy the requirement of SL25-2006 and SL282-2003 technical specification.

  18. 横缝灌浆对向家坝岸坡反拱坝段工作特性影响研究%Influence of Transverse Joint Grouting on Working Performance of Xiangjiaba Slope Anti-arch Dam Section

    Institute of Scientific and Technical Information of China (English)

    周秋景; 杨波; 廉成志; 李海枫; 吴龙珅

    2012-01-01

    In order to determine the influence of transverse joints grouting on working performance of anti arch dam section of gravity dam, deformation and stress of Xiangjiaba slope anti arch dam section under action of temperature load are calculated by using FEM. The results show that variation of dam deformation and dam heel stress are influenced significantly by transverse joints grouting;transverse joints should not be grouted if each dam section meets stability condition.%为明确横缝灌浆对采用反拱形式布置的重力坝坝体工作性态的影响,采用三维有限元方法分析了向家坝岸坡反拱坝段在单独温度作用下的变形和应力.结果显示,横缝灌浆对坝体变形和坝踵应力变化规律影响显著;在单坝段满足稳定条件下横缝不宜灌浆.

  19. AutoCAD Civil 3D在双曲拱坝建模中的应用%Application of AutoCAD Civil3D in Modeling of Double-Curvature Arch Dam

    Institute of Scientific and Technical Information of China (English)

    王奕钦

    2015-01-01

    With the case of the double-curvature arch dam whose outline is complicated in water resources and hydropower projects.Applica-tion of Civil 3D in dam modeling is described in terms of establishment of the original topographic curve, arrangement of components of the arch-dam outline, setting-out of the dam arc curve, slope excavation, calculation of work quantities of excavation and backfill, etc.The ap-plication prospects of the application of AutoCAD Civil 3D in water resources and hydropower projects are summarized, providing the designer of water resources and hydropower projects with reference.%以水利水电工程中大坝体型较为复杂的双曲拱坝为例,从原始地形曲面创建、拱坝体型装配设置、大坝圆弧曲线放样、边坡开挖、挖填方工程量计算等方面介绍了Civil 3D在水利工程中坝体建模方面的应用。总结了Au-toCAD Civil 3D在在水利工程中的应用前景,可为水利水电工程设计者提供参考。

  20. High arch

    Science.gov (United States)

    Pes cavus; High foot arch ... High foot arches are much less common than flat feet. They are more likely to be caused ... difficult to fit into shoes. People who have high arches most often need foot support. A high ...

  1. 浅水爆炸冲击荷载下高拱坝抗爆性能分析%Antiknock Performance of High Arch Dam Subjected to Shallow Water Explosion

    Institute of Scientific and Technical Information of China (English)

    张社荣; 王高辉

    2013-01-01

    Under underwater blasting shock load,the dynamic response of structures is much more complicated than that under other loadings such as static loading and earthquake loading.Strain rate effect of concrete dam is taken into consideration in the establishment of high arch dam fully coupled model.Numerical simulation method is used to study the dynamic response of the dam bearing strong underwater explosion shock loading.The response,possible failure mode and corresponding failure mechanism of high arch dam are discussed.The influence of blast center distance and amount of explosives on the blast resistance of the dam is also investigated.Numerical results indicate that arch dams,due to the mechanical characteristics of the arch,have a higher carrying capacity.In general,smaller equivalent explosive under impact loads only causes partial dehiscence of the dam.When large equivalent explosive explodes in shallow water,severe crushing and shear failure appear in the middle of the dam top.Crack extending-downwards to the half of dam height will cause severe damage of the dam.%水下爆炸冲击荷载作用下大坝动力响应较之静态荷载和地震荷载作用下要复杂得多.通过构建高拱坝水下爆炸大型数值全耦合模型,考虑混凝土材料的高应变率效应,采用三维非线性有限元法对近水面水下爆炸冲击荷载作用下的大坝动态响应进行了全性能数值仿真,探讨了高拱坝在浅水爆炸冲击荷载作用下的动力响应、潜在破坏模式及失事机理,研究了爆心距及炸药量对大坝抗爆性能的影响.研究结果表明:拱坝由于其拱形受力特点,具有较高的承压能力;在常规小当量炸药爆炸冲击荷载作用下,坝体仅产生局部开裂破坏;当大当量高能炸药在库区浅水近场爆炸时,上游面坝顸中部发生严重压碎和剪切破坏并形成上下游贯穿的裂缝,且裂缝向坝体下部扩展至1/2坝高处,导致坝体产生严重破坏.

  2. 基于弹性有限元的高拱坝安全度敏感性分析%Sensitivity Analysis of High Arch Dam Safety Based on Elastic Finite Element

    Institute of Scientific and Technical Information of China (English)

    王志强; 李同春; 沈德才

    2011-01-01

    以溪洛渡高拱坝为例,针对弹性有限元评价高拱坝安全度存在的问题,以基本荷载组合作为基本研究工况,考虑整体自重、分缝自重及施工浇筑过程自重三种自重荷载作用方式,研究可能的水荷载与温度荷载变化、地质条件变化及大坝材料的抗力变化,分析变化量对大坝安全度的敏感性.计算结果表明,对温降工况,影响建基面相对受拉面积的因素从大到小依次为水荷载、混凝土弹模、地基弹模、自重作用方式、温度荷载.%The elastic finite element has drawbacks for evaluating high arch dam safety. Taking Xiluodu high arch dam for an example, based on the conditions of basic load combination, possible water load change, temperature load change, possible geological condition change and dam material resisting force change are studied by considering three dead weight load function ways of overall weight, parting weight and weight in process of construction. And the sensitivity of above-mentioned change to dam safety is analyzed. The results show that for the temperature falling conditions, the fac tors influencing foundation plane relative tension area rank from large to small as follows: water load, concrete elastic modulus, foundation elastic modulus, weight function way and temperature load.

  3. Prediction of arch dam deformation based on Markov Chain- Kalman filter method%基于马尔可夫链-卡尔曼滤波法的拱坝变形预测

    Institute of Scientific and Technical Information of China (English)

    孙一帆; 沈振中; 聂柏松; 杨磊

    2014-01-01

    Deformation monitoring and early warning analysis of the dam play a key role in the healthy operation of dam. H ow ev-er, there are unavoidable random errors in the monitoring data. Kalman filtering met hod can eliminate the noise from t he ob-served data effect ively; however, the prediction of the displacement trend of the dam does not agree w ell w ith the actual condi-tions using this method. In this paper, Markov chain-Kalman filter method w as proposed, w hich can not only remove the random error but also predict the displacement accurately. Based on the observed displacement data of an arch dam in Zhejiang Province, the method show ed an accurate prediction of dam deformation. Therefore, Markov chain-Kalman filter met hod can be used in the prediction of arch dam deformation and security monit oring.%变形监测分析和预警对大坝健康运行起着关键的作用,但是监测数据都不可避免地存在随机误差。卡尔曼滤波法可以有效地剔除测量数据中的噪声,然而,利用其对大坝未来的趋势位移做出预测时与实际情况吻合度不高。因此提出了马尔可夫链-卡尔曼滤波法,既能剔除测量数据噪声又可以准确的预测未来位移。利用浙江某拱坝位移实测资料,拟合并预测了该大坝的变形,验证结果表明该方法的拟合预测效果良好,可用于拱坝变形预测和安全监控。

  4. Stability Analysis of A Gravity Arch Dam Using Three-dimensional Finite Element Method%重力拱坝坝体三维有限元稳定分析

    Institute of Scientific and Technical Information of China (English)

    彭成山; 于丽红; 范冰

    2015-01-01

    Because the gravity arch dam is gravity based which puts great stress on the beams ,so stability issue becomes the main problem of these dams .In order to verify the safety and feasibility of the gravity arch dam design of a reservoir , the finite element software ADINA was adopted to carry out a three dimensional stability analysis for the dam .The defor-mation of the dam under different stress at the normal storage level ,the design flood level and check flood level were cal-culated through the simulation .The results indicate that the distribution of stress and strain of the dam body are in line with the actual situation and the values are within the allowed range .This study will not only provide an important techni-cal support for practical engineering design and construction ,but also an effective reference for the similar engineering constructions .%由于重力拱坝主要依靠梁的作用即以重力作用为主,所以稳定问题显得更重要。为了验证某水库重力拱坝坝体设计的安全性与可行性,采用有限元计算软件 ADINA 对该重力拱坝进行了三维稳定分析,模拟计算出了正常蓄水位、设计洪水位、校核洪水位下的坝体应力变形情况。从计算结果可以看出,该坝坝体的应力应变分布规律均符合实际情况且应力值都在允许的范围内。不仅为实际工程的设计和修建提供了重要的技术依据,同时也为同类工程建设提供了有效的参考。

  5. 应力与渗流耦合作用下溪洛渡拱坝变形稳定分析%DEFORMATION STABILITY ANALYSIS OF XILUODU ARCH DAM UNDER STRESS-SEEPAGE COUPLING CONDITION

    Institute of Scientific and Technical Information of China (English)

    林鹏; 刘晓丽; 胡昱; 许文彬; 李庆斌

    2013-01-01

    The detailed analyses of the geological conditions of the Xiluodu arch dam foundation under stressseepage coupling are carried out.Based on field monitoring data,the paper tries to understand the mechanism of seepage coupling in the foundation of Xiluodu dam,where seepage pressure and water level fluctuation are considered.In this paper,the seepage parameters and boundary conditions are determined based on the seepage simulations in combination of field monitoring.The relationship between permeability and stress-deformation is established.By using the nonlinear finite element method,the integrity seepage stability of dam foundation in the typical stages of construction period is numerically studied.Based on the deformations and compressive stresses obtained by numerical simulations and field monitoring data,the seepage state of the dam foundation during construction is obtained.Next,seepage stabilities of dam during operation period are predicted,which may be employed for seepage controlling system of the dam site.Finally,it is noted that the safety and construction quality of the dam during impounding process should be ensured.%以溪洛渡工程为例,通过对大坝基础地质条件、岩体内应力-渗流耦合作用机制的详细分析,基于现场监测数据,对大坝复杂基础的渗流耦合作用机制和渗压、水位变化规律进行分析;对比渗流场分析结果和实测结果,确定岩层的渗透参数及边界条件.建立裂隙岩体渗透特性和应力-变形的关系,采用非线性有限元方法,对施工期典型阶段的大坝基础渗流工作状态进行三维数值精细模拟分析,分析结果与现场变形和压应力监测值进行对比,得到施工期大坝复杂基础的渗透真实工作状态,预测大坝运行期的渗流工作性态,从而指导大坝现场渗控体系施工,对保证蓄水过程的施工质量和大坝安全具有重要指导意义.

  6. Three-dimensional Finite Element Optimization Analysis of Different Seepage Control Schemes of Lizhou RCC Arch Dam%立洲RCC拱坝渗控方案的三维有限元优化分析

    Institute of Scientific and Technical Information of China (English)

    行亚楠; 胡升伟; 王滔; 吴震宇; 陈建康

    2013-01-01

    The seepage control measures were investigated for the dam area of Lizhou hydroelectric project in Muli River of Si‐chuan Province .A three‐dimensional finite element seepage model was developed using ANSYS12 .1 to analyze the seepage char‐acteristics and variations of seepage pressure under different seepage control schemes .The seepage gradient and seepage amount of key positions and the seepage pressure and groundwater level of typical profiles of seepage field for different seepage control schemes were compared .The results showed that (1) the impervious curtain and drainage hole in the design scheme of seepage control measures of Lizhou arch dam can decrease the seepage saturation line effectively ,lower the uplift pressure on dam foun‐dation and dam abutment ,and improve the stress conditions of dam foundation and dam abutment ;(2) the deepening curtain , drainage hole ,and thickening curtain have insignificant effects on decreasing the seepage pressure ;and (3) increasing the depth of impervious curtain near the f 5 fault can prevent the formation of leakage passage in the f 5 fault .In addition ,removing the drainage hole in the first layer and decreasing the extending length of the impervious curtain of dam abutment can save the cost of seepage control measures without breaking seepage safety .%  以四川木里河立洲水电枢纽工程为研究对象,对坝区的渗控措施展开研究.利用ANSYS12.1建立三维有限元渗流模型,计算分析得到了各渗控方案的渗流特征和渗透压力变化规律.对各方案中关键部位的渗透比降、渗漏量和典型剖面渗流场的渗压、地下水位等特征量进行比较分析后,得知:(1)立洲拱坝渗控措施设计方案的防渗帷幕和排水孔幕能有效降低坝后渗流浸润线,对于减小坝基、坝肩扬压力、改善坝基和坝肩受力条件起到了良好的作用;(2)加深帷幕和排水孔幕、增厚帷幕对降低坝

  7. Causing-analysis on the difference between monitoring and elastic calculating results of dam heel stress for high arch dams%高拱坝坝踵应力实测与弹性计算结果差异原因分析

    Institute of Scientific and Technical Information of China (English)

    张国新; 周秋景

    2013-01-01

      坝踵应力是关系到混凝土坝是否开裂和安全的一个重要指标,不管是用结构力学法还是有限元法都能计算出坝踵有一定的拉应力,但实际监测中却很少出现。本文从定性和定量两个方面分析造成计算结果和实测结果差异的原因,以小湾特高拱坝为例分析影响计算精度的各项主要因素,在此基础上提出坝踵真实应力的仿真分析方法。结果显示,计算和实测应力差异原因主要在于以下3个方面:(1)坝踵位置的定义不同;(2)目前监测仪器和方法有局限性;(3)计算过程中的不当简化,如自重和水压的施加方式、坝体温度荷载的考虑、库水温度分布以及库盆水压的影响等。改进后的仿真分析结果与监测结果吻合良好,说明该方法能够给出合理的坝踵应力变化规律和比较精确的应力范围。最后,给出了坝踵应力监测仪器和方法的改进建议。%  Dam heel stress is a key indicator concerning concrete cracks and dam safety. Tension stress is generally got in a dam heel by structure mechanics or finite element methods, while seldom be monitored with instruments. The reason for the difference between simulation and monitoring results is analyzed qualita⁃tively and quantitatively. With Xiaowan arch dam,for example,the main factors affecting simulation accura⁃cy are studied and an improved simulation method is proposed to give more real and accurate dam heel stress. The results show that the reason mainly lie in the following:(1) different definition of dam heel be⁃tween simulation and monitor;(2) limitation of monitoring methods and instruments;(3) improper simplifi⁃cation in simulations,such as the way to preload self-weight and water pressure,to consider thermal loads in a dam and distribution of water temperature in reservoir, and impact of basin water pressure etc. The im⁃proved simulation results are in good agreement

  8. 特克斯河山口引水枢纽的 引水防沙设计及试验研究%Dynamic test and study on the integral body and model with transverse joint of Xiaowan High Arch Dam

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    通过特克斯河山口引水枢纽的试验研究,解决了常遇洪水低水位运行时河流两岸的引水问题,优化了水平悬板等结构形式,收到了较好的引水防沙效果,为悬板分层式引水枢纽工程设计提供了新经验%The dynamic test on the earthquake response of the integral dam body and model with transverse joint for Xiaowan High Arch Dam was made. In consideration that the dynamic test on the model with transverse joint falls into non-linear category, it is more sensitive to the initial condition of static action so that the test includes reservoir with a length of three times dam height. The test on expansion transverse joint was made in two working conditions. Firstly three expansion transverse joints were set up in the arch-crown beam and top arch, about 1/4 arc length of right and left banks. Then five transverse joints were increased to make dynamic test. The test showed that under the working condition of normal high water level, the transverse joint of dam body under the action of earthquake opens indistinctly. But under the low water level, the transverse joint clearly opens because of the reduction of static pressure. The dynamic tensile stress of dam body obviously reduces and the dynamic beam stress increases obviously. The initial condition of the transverse joints of dam body will bring big impact on the opening of transverse joint. On the basis of the designed reinforcement, the test showed that the opening of transverse joint reduced about 20%.

  9. Challenges of high dam construction to computational mechanics

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chuhan

    2007-01-01

    The current situations and growing prospects of China's hydro-power development and high dam construction are reviewed,giving emphasis to key issues for safety evaluation of large dams and hydro-power plants,especially those associated with application of state-of-the-art computational mechanics.These include but are not limited to:stress and stability analysis of dam foundations under external loads;earthquake behavior of dam-foundation-reservoir systems,mechanical properties of mass concrete for dams,high velocity flow and energy dissipation for high dams,scientific and technical problems of hydro-power plants and underground structures,and newly developed types of dam-Roll Compacted Concrete (RCC) dams and Concrete Face Rock-fill (CFR)dams.Some examples demonstrating successful utilizations of computational mechanics in high dam engineering are given,including seismic nonlinear analysis for arch dam foundations,nonlinear fracture analysis of arch dams under reservoir loads,and failure analysis of arch dam-foundations.To make more use of the computational mechanics in high dam engineering,it is pointed out that much research including different computational methods,numerical models and solution schemes,and verifications through experimental tests and filed measurements is necessary in the future.

  10. Research on the impact analysis of Xiatun arch dam right abutment K6 karst cave and treatment plan%下屯拱坝右坝肩 K6溶洞影响分析及处理方案研究

    Institute of Scientific and Technical Information of China (English)

    王国香; 钱刚

    2016-01-01

    K6 karst cave is developed in 1140 ~1160m elevation of Xiatun arch dam right abutment.The cave is filled by clay and stones.The karst cave has larger scale,which is not beneficial for the stability of dam abutment.The karst cave has lower influence on the stability of dam abutment and downstream rocks according to analysis.The karst cave is excavated in order to improve the safety and reliability of the abutment.Concrete is backfilled,and concrete gravity pier is set.The above measures are introduced in the paper.%下屯水电站右坝肩在1140~1160m 高程发育 K6溶洞,洞内黏土夹块石充填,溶洞规模较大,对拱坝坝肩的稳定不利。经分析溶洞对拱坝坝肩及下游岩体稳定的影响较小,但为了提高坝肩的安全可靠性,对溶洞进行了清挖,并回填混凝土及设置了混凝土重力墩。本文对此加以介绍。

  11. 基于块体元的塑性极限下限法在拱坝坝肩稳定分析中的应用%Application of plastic limit lower bound method to stability analysis of arch dam abutment based on block elements

    Institute of Scientific and Technical Information of China (English)

    任顺; 王均星; 邓念武

    2012-01-01

    A block element lower bound limit analysis method for the stability of arch dam abutment is presented through combining block element method with lower bound limit analysis method.By utilizing block element method to disperse calculation areas,and satisfying some conditions for the block system static field in structure surface such as Mohr-Coulomb yield conditions,stress boundary conditions and the force vector and moment balance principle in block elements,a mathematical programming model solving lower bound solution of arch dam abutment strength reserve coefficient can be constituted.The interior point algorithm is employed to solve the model.Finally,a wedge example and a test of Qinglong arch dam left abutment are researched.The calculated results obtained by block element lower bound method are compared with rigid body limit equilibrium method;it is shown that the proposed method is feasible.%将块体单元法与极限分析下限法相结合,提出了拱坝坝肩稳定的块体单元极限分析下限法.借助于块体单元法离散计算区域,通过块体系统静力场在结构面上满足Mohr-Coulomb屈服条件、应力边界条件以及在块体单元上的力矢力矩平衡原理,构成求解拱坝坝肩强度储备安全系数下限解的数学规划模型,模型的求解采用内点法.最后研究了一个楔形体算例和青龙拱坝左岸坝肩实例,通过比较块体单元下限法计算结果与刚体极限平衡法计算结果,验证了该方法的可行性.

  12. Discussion on construction and type selection of China high dams

    Institute of Scientific and Technical Information of China (English)

    Zhou Jianping; Yang Zeyan; Chen Guanfu

    2009-01-01

    At the beginning of 21st century, with the rapid and steady development of China economy, a lot of large scale hydropower projects with large dams from 200 m to 300 m high are being or to be buih. China dam constructions are reaching the level of 300 m high arch dam, 250 high CFRD (concrete face rockfill dam) and 200 m high RCC (roller compacted concrete) gravity dam. Due to the safety and the economy, the type selection for high dams has become the key issue during the argumentation for the hydropower projects, and further efforts are still needed in this aspect for high dams. After reviewing the high dam constructions in China and abroad, authors proposed some advices for the selection of dam types, and hope that it can provide some helpful information for the researches and the design of high dams.

  13. 基于模型试验与变形加固理论的高拱坝整体稳定性判据研究%CRITERION OF GLOBAL STABILITY OF HIGH ARCH DAM STRUCTURES BASED ON MODEL TEST AND EDFORMATION REINFORCEMENT THEORY

    Institute of Scientific and Technical Information of China (English)

    程立; 刘耀儒; 潘元炜; 杨强; 周维垣

    2014-01-01

    During the entire failure process,high arch dam as a statically indeterminate rock structure breaks locally at first;then the whole system enters the nonlinear deformation stage;and finally the overall structure failure happens. Consequently,it is difficult to evaluate the global stability of a high arch dam using a single criterion. In this paper,the entire failure process was analysed adopting the overload method to study the stability of high arch dams. Meanwhile,3 safety factors(K1,K2,K3) based on the geological model test and the norm criterion of the curve of plastic complementary energy were discussed and compared. 3 safety factors(K-1,K-2,K-3) to simulate the failure process were proposed in this paper by using the theory of deformation reinforcement. The relationships between K1,K2,K3 and K-1,K-2,K-3 were discussed through analysing the results of model tests and the numerical computations completed in recent years. Results indicate that high consistency exists between two criteria and two criteria can validate each other.%高拱坝结构作为超静定的岩体工程结构,在破坏过程中,首先发生局部起裂,然后整体进入非线性变形阶段,最后发生整体破坏,因此难以用单一的稳定性判据衡量高拱坝的整体稳定性。使用超水荷载法研究拱坝的稳定性,分析拱坝整体结构在超载过程中的破坏过程。对基于地质力学模型试验的三安全度(K1,K2,K3)评价标准和基于非线性数值模拟的超载倍数-塑性余能曲线评判标准进行对比分析。同时,利用变形加固理论能够近似模拟结构发生局部破坏后应力、位移情况的优势,提出基于变形加固理论的拱坝三安全度评判标准K-1,K-2,K-3。通过对模型试验和数值计算的结果归纳分析,分别论述模型试验的 K1,K2,K3与数值计算的 K-1,K-2,K-3之间的联系。结果表明,基于地质力学模型试验的三安全度评价标准K1,K2

  14. Simulation of the thermal behaviour of a concrete dam using in situ measurements : case of Daniel-Johnson dam

    Energy Technology Data Exchange (ETDEWEB)

    Thibeault, N. [Tecsult Inc., Montreal, PQ (Canada); Lariviere, R. [Hydro-Quebec, Montreal, PQ (Canada)

    2004-09-01

    The Daniel-Johnson Dam is the largest multiple-arch dam in the world. It was completed in 1969 at a height of 214 metres. The dam has faced many challenges related to severe thermal conditions, presence of plunging cracks in many arches and opening at the rock-concrete interface. Major concerns lie with the shear resistance in the plane of the plunging cracks. It has been determined that the main cause of arch degradation is related to the thermal behaviour of the dam. A thermal shelter was therefore constructed in the lower part of the arches. This protection has proved to be very effective. A decision was later taken to grout the plunging cracks of some arches. This involved the verification of the structural stability of the arch base. To accomplish this, the shear safety factor during the proposed injection had to be validated. This paper discussed the complex challenge of simulating the thermal behaviour of a concrete dam. It presented an alternative to the conventional methods to implement a thermal profile in a finite element model. Synthetic curves of the thermal profile were used for different thicknesses and boundary conditions. The curves were then interpolated for intermediate thicknesses. A numerical model developed for this project has been verified according to the recommendations of Bulletin 94 of ICOLD (Computer Software for Dams). The loads to consider within the framework study of the Daniel-Johnson Dam gravity; thermal gradient in summer and winter; thermal protection; hydrostatic pressure; uplift pressure in cracks; hydrostatic pressure at upstream on the grout curtain; rock-concrete contact opening; and grout pressures. The proposed method has proven to be simple, efficient and easily implemented to rapidly determine the thermal behaviour of the structures. It is also particularly well suited for multiple-arch dams. The thermal structure analysis was used to determine deformation which was compared with measurements of the pendulums. 8 refs

  15. Dams (National)

    Data.gov (United States)

    Department of Transportation — This map layer portrays major dams of the United States, including Puerto Rico and the U.S. Virgin Islands (NTAD 2015). The map layer was created by extracting dams...

  16. Intraoral gothic arch tracing.

    Science.gov (United States)

    Rubel, Barry; Hill, Edward E

    2011-01-01

    In order to create optimum esthetics, function and phonetics in complete denture fabrication, it is necessary to record accurate maxillo-mandibular determinants of occlusion. This requires clinical skill to establish an accurate, verifiable and reproducible vertical dimension of occlusion (VDO) and centric relation (CR). Correct vertical relation depends upon a consideration of several factors, including muscle tone, inter-dental arch space and parallelism of the ridges. Any errors made while taking maxillo-mandibular jaw relation records will result in dentures that are uncomfortable and, possibly, unwearable. The application of a tracing mechanism such as the Gothic arch tracer (a central bearing device) is a demonstrable method of determining centric relation. Intraoral Gothic arch tracers provide the advantage of capturing VDO and CR in an easy-to-use technique for practitioners. Intraoral tracing (Gothic arch tracing) is a preferred method of obtaining consistent positions of the mandible in motion (retrusive, protrusive and lateral) at a comfortable VDO.

  17. 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...

  18. Safety and coping strategy for high dam under complex natural conditions

    Institute of Scientific and Technical Information of China (English)

    Niu Xinqiang

    2012-01-01

    In respect to current situation and new challenges for high dam construction in China, safety problems are an- alyzed for high dam construction under complex natural conditions such as high elevation, cold area, high seismic inten- sity, large-seale landslide and high dam and huge reservoirs with dam types such as concrete surface rock-fill, asphalt concrete core, roller compacted concrete (RCC) arch dam and so on. From several aspects, including risk response measures for high dam, strengthening safety awareness for high dam design and construction, improving high dam con- struetion technique, intelligent dam safety management system based on IT, developing dam rehabilitation and mainte- nance technologies, useful dam safety and coping strategy is proposed.

  19. 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/

  20. 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.

  1. Double arch mirror study

    Science.gov (United States)

    Vukobratovich, D.; Hillman, D.

    1983-01-01

    The development of a method of mounting light weight glass mirrors for astronomical telescopes compatible with the goals of the Shuttle Infrared Telescope Facility (SIRTF) was investigated. A 20 in. diameter double arch lightweight mirror previously fabricated was modified to use a new mount configuration. This mount concept was developed and fabricated. The mounting concept of the double mounting mirror is outlined. The modifications made to the mirror, fabrication of the mirror mount, and room temperature testing of the mirror and mount and the extension of the mirror and mount concept to a full size (40 in. diameter) primary mirror for SIRTF are discussed.

  2. Gene Wash and Copper Basin Dams are surviving alkali-aggregate reaction

    Energy Technology Data Exchange (ETDEWEB)

    Hill, C.J.

    1995-12-31

    Gene Wash and Copper Basin Dams were constructed in 1937 and 1938, and are owned and operated by the Metropolitan Water District of Southern California (MWD). The dams are located in San Bernardino County, California, close to the Colorado River, and very close to the easternmost point of California. They form two intermediate storage facilities on the Colorado River Aqueduct system which conveys water from Lake Havasu to the Los Angeles and San Diego areas. The locations of the dams are shown. Gene Wash Dam is a concrete arch structure, with a maximum height of arch of 131 feet. There is a gravity thrust block on the right abutment and the total crest length is 430 feet. Copper Basin Dam is a concrete arch dam with a maximum height of arch of 187 feet and a crest length of 253 feet. Plans, elevations and sections for both dams. The dams are in the Whipple Mountains at the eastern edge of the Mojave Desert. Between June and October, maximum temperatures usually exceed 100 degrees Farenheit, while daily low temperatures in this period are generally in the 60`s and 70`s. Winter temperatures are mild, with daytime highs in the 70`s and 80`s, and lows only occasionally below freezing. The area is arid, with total annual rainfall generally between two and ten inches. Both dams were built in desert washes with no permanent flow. The foundation for both structures is a strong, erosion-resistant, red-brown, non-marine sandstone and conglomerate of Tertiary age known as the Copper Basin Formation (Buwalda, 1937). Spillways for both dams are ungated ogee crests, which are separate from the dams. Gene Wash Dam and Copper Basin Dam are geographically close together, are of similar design, and were constructed at the same time, using the same materials. Their performance since construction, not surprisingly, has been similar.

  3. Dam Safety Concepts

    NARCIS (Netherlands)

    Duricic, J.

    2014-01-01

    The majority of dams constructed in the world are dams that can be categorized as embankment dams. Throughout history we can point to many failures of dams, and embankment dams in particular. Nowadays it is clear that the goal to construct stable dams has not been achieved, even with advanced techno

  4. Using ArchE in the Classroom: One Experience

    Science.gov (United States)

    2007-09-01

    displaying the new itinerary The team initially adopted the Model-View-Controller ( MVC ) architecture as the top-level architecture . The...CMU/SEI-2007-TN-001 Software Architecture Technology Initiative Unlimited distribution subject to the copyright. This report was prepared...SOFTWARE ENGINEERING INSTITUTE | v vi | CMU/SEI-2007-TN-001 Abstract The Architecture Expert (ArchE) tool serves as a software architecture

  5. Crack status analysis for concrete dams based on measured entropy

    Institute of Scientific and Technical Information of China (English)

    WU BangBin; WU ZhongRu; CHEN Bo; SU HuaiZhi; BAO TengFei; WANG ShaoWei

    2016-01-01

    The integrity and safety of concrete dams are seriously affected by the existing cracks in dam bodies,and some serious cracks may cause dam failure or disaster.The propagation of cracks in concrete dams is accompanied by changes in energy distribution,which can be represented by changes in the structure's system entropy.Therefore,the entropy theory can be used in analyzing the behavior of dam cracks.Due to the randomness and locality of crack propagation,it is difficult to predict the location of cracks by traditional monitoring methods.To solve this problem,the influence of spatial positions of monitoring points on inspection zones is represented by a weight index,and the weight index is determined by the distance measure method proposed in this paper.Through the weighted linear fusion method,the entropy of multiple monitoring points is obtained for analyzing the behavior of dam cracks in the selected zones.Meanwhile,the catastrophe theory is used as the variation criterion of an entropy sequence in order to predict the instability time of dam cracks.Case studies are put forward on a high arch dam,and the fusion entropy is calculated according to the monitoring data from strain gauges.Results show that the proposed method can effectively predict the occurrence time and location of dam cracks regardless of the layout of monitoring instruments,and it is a new way to analyze the occurrence and propagation of dam cracks.

  6. 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.

  7. Arch bridges – unlocking their potential

    OpenAIRE

    Long, Adrian; Nanukuttan, Sreejith

    2016-01-01

    Arch bridges are strong, durable, aesthetically pleasing and require little maintenance but very few have been built since the early 1900s. However, this trend has changed as more than 60 FlexiArch bridges have been installed since the system was launched in 2007. The FlexiArch uses precast concrete voussoirs, requires neither corrodible reinforcement, nor centring, can be installed in hours and is contractor friendly. Details of this innovative method of construction and installation of arch...

  8. Dynamic dam-reservoir interaction analysis including effect of reservoir boundary absorption

    Institute of Scientific and Technical Information of China (English)

    LIN; Gao; DU; JianGuo; HU; ZhiQiang

    2007-01-01

    Based on the scaled boundary finite-element method,the governing equations for the analysis of dam-reservoir interaction including the reservoir boundary absorption are developed.Coupling with the equation of dam-unbounded foundation interaction,it can effectively carry out the earthquake response analysis of dam-reservoir-foundation system.The proposed approach has the advantages that the effect of compressibility of reservoir water as well as the energy absorption of reservoir boundary on the earthquake response of arch dams and gravity dams can be efficiently evaluated and higher accuracy can be achieved.In comparison with the methods available in the literature,the computational cost can be reduced to a great extent.It facilitates the application of earthquake response analysis of dam-reservoir-foundation system including reservoir boundary absorption to the engineering practice.

  9. Comparison between different plantar arch

    OpenAIRE

    2009-01-01

    The longitudinal plantar arch (LPA) perform biomechanics functions in the foot. The aim of this study was to compare the relationship between different index to measure the LPA of the foot. The arc index, Staheli index, Viladot classification and Feiss line were compared. In the transversal study, the experimental samples were soccer players females with age between 13 to 19 years. The measure were performed by plantigraphy, with out Feiss line. Although non significant the higher agreement w...

  10. 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.

  11. Alpine dams

    Directory of Open Access Journals (Sweden)

    Alain Marnezy

    2009-03-01

    Full Text Available Les barrages-réservoirs de montagne ont été réalisés initialement dans les Alpes pour répondre à la demande d’énergie en période hivernale. Une certaine diversification des usages de l’eau s’est ensuite progressivement développée, en relation avec le développement touristique des collectivités locales. Aujourd’hui, la participation des ouvrages d’Électricité De France à la production de neige de culture représente une nouvelle étape. Dans les régions où les aménagements hydroélectriques sont nombreux, les besoins en eau pour la production de neige peuvent être résolus par prélèvements à partir des adductions EDF. Les gestionnaires de stations échappent ainsi aux inconvénients liés à la construction et à la gestion des « retenues collinaires ». Cette évolution, qui concerne déjà quelques régions alpines comme la haute Maurienne ou le Beaufortin, apparaît comme une forme renouvelée d’intégration territoriale de la ressource en eau.Mountain reservoirs were initially built in the Alps to meet energy needs in the winter. A certain diversification in the uses of water then gradually developed, related to tourism development in the local communities. Today, the use of facilities belonging to EDF (French Electricity Authority to provide water for winter resorts to make artificial snow represents a new phase. By taking water from EDF resources to supply snow-making equipment, resort managers are thus able to avoid the problems related to the construction and management of small headwater dams. This new orientation in the use of mountain water resources already affects a number of alpine regions such as the Upper Maurienne valley and Beaufortain massif and represents a renewed form of the territorial integration of water resources.

  12. Iran funds dam completion

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Iran has signed a contract with unnamed foreign financiers for US$300M to fund two half-finished dam schemes, according to Tehran radio. The schemes are the Ostur dam in Mianeh in East Azerbaijan province and the Molla Sadra dam in Fars province. The Ostur dam will have a storage capacity of 2B m3 and a 160 MW hydro power station.

  13. Hoover Dam Learning Packet.

    Science.gov (United States)

    Bureau of Reclamation (Dept. of Interior), Washington, DC.

    This learning packet provides background information about Hoover Dam (Nevada) and the surrounding area. Since the dam was built at the height of the Depression in 1931, people came from all over the country to work on it. Because of Hoover Dam, the Colorado River was controlled for the first time in history and farmers in Nevada, California, and…

  14. Analyzing Engineering Geology Condition of Dam Site of Mohe Water Supply Hydroproject and Comparing Type of Dam%磨河供水工程枢纽坝址工程地质条件分析及坝型比选

    Institute of Scientific and Technical Information of China (English)

    高峰

    2012-01-01

    In this paper,the strata textures and structures of dam foundation and dam abutment of Mohe Water Supply Hydroproject are investigated,surveyed and analyzed,Through initial analysis on stability of dam foundation and dam abutment,the applicability of two dam types is compared roughly.The two types of dam are stone masonry gravity dam and arch dam.And the gravity dam is recommended.%对磨河供水工程枢纽坝址的坝基、坝肩地层结构、构造进行了调查、勘测研究。通过坝基、坝肩的稳定性初步分析,比较了浆砌石重力坝及拱坝的适用性,推荐采用重力坝。

  15. Revisiting impressions using dual-arch trays.

    Science.gov (United States)

    Small, Bruce W

    2012-01-01

    Making routine perfect impressions is the goal of any restorative dentist. Using dual-arch trays is an easy, repeatable way to accomplish that goal, as long as each step is done before the next and each step is performed perfectly. This column reviewed several articles that support the metal dual-arch concept and provided some clinical tips that might help restorative dentists. The dual-arch technique does have its limits and is meant for one or two teeth in a quadrant when there are other teeth to occlude with. Also, if the case involves anterior guidance, a full-arch impression maybe advisable.

  16. 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.

  17. Occlusal stability in shortened dental arches.

    Science.gov (United States)

    Witter, D J; Creugers, N H; Kreulen, C M; de Haan, A F

    2001-02-01

    Shortened dental arches consisting of anterior and premolar teeth have been shown to meet oral functional demands. However, the occlusal stability may be at risk as a result of tooth migration. The aim of this nine-year study was to investigate occlusal stability in shortened dental arches as a function over time. Occlusal stability indicators were: 'interdental spacing', 'occlusal contacts of anterior teeth in Intercuspal Position', 'overbite', 'occlusal tooth wear', and 'alveolar bone support'. Subjects with shortened dental arches (n = 74) were compared with subjects with complete dental arches (controls, n = 72). Repeated-measurement regression analyses were applied to assess age-dependent variables in the controls and to relate the occlusal changes to the period of time since the treatment that led to the shortened dental arches. Compared with complete dental arches, shortened dental arches had similar overbite and occlusal tooth wear. They showed more interdental spacing in the premolar regions, more anterior teeth in occlusal contact, and lower alveolar bone scores. Since the differences remained constant over time, we conclude that shortened dental arches can provide long-term occlusal stability. Occlusal changes were self-limiting, indicating a new occlusal equilibrium.

  18. Dam to the Rescue

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The Three Gorges Dam relieves the summer drought in south and central China,but may contribute to other problems The Three Gorges Dam played an important role in relieving China’s drought in central and eastern prov-inces that had been using increased water discharges from the Dam to irrigate dry farmlands facing the worst drought int he last 60 years in 2011.

  19. Cyclic behavior test of a new double-arch steel gate

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new double-arch structure for the gate used as tidal barrage and sluice was adopted in Caoe River Dam in China. It was a spatial structure made up of the right arch, the invert arch, the chord, etc., and was designed to bear bilateral loads. To research the cyclic behavior of the new double-arch structure, a scale-model cyclic test was conducted. First, the test setup and test method were presented in detail, and according to the test results, the cyclic behavior and failure characteristics of this structure were discussed. Then by analyzing the test cyclic envelope curve, it was found the curve was divided into three stages: the elastic stage, the local plastic stage and the failure stage at the local yield point and structural yield point. The gate model has local yield strength and structural yield strength, with both their values being bigger than that of the designing load. Therefore, the gate is safe enough for the projects. At last, dynamic property of the gate was analyzed considering additional mass of the water. It was found that the tidal bore shock would not cause resonance vibration of the gate.

  20. Persistent fifth arch anomalies - broadening the spectrum to include a variation of double aortic arch vascular ring

    Energy Technology Data Exchange (ETDEWEB)

    Newman, Beverley; Chan, Frandics [Stanford Children' s Hospital and Stanford University, Department of Radiology, Stanford, CA (United States); Hanneman, Kate [University of Toronto, Department of Medical Imaging, Toronto, ON (Canada)

    2016-12-15

    Fifth arch anomalies are rare and complex and frequently misdiagnosed or mistaken for other entities. We report a double arch vascular ring that is thought to consist of right fourth arch and left fifth arch components, a previously undescribed persistent fifth arch variant. The currently recognized spectrum and classification of fifth arch vascular anomalies are expanded along with illustrative images to justify the proposed changes. Reviewing and expanding the classification of fifth arch anomalies to include a double arch ring variant will promote recognition, correct diagnosis and appropriate management of these anomalies. (orig.)

  1. Analysis of irreversible displacements of Daniel-Johnson dam

    Energy Technology Data Exchange (ETDEWEB)

    Chouinard, L.; Zhao, W. [McGill Univ., Montreal, PQ (Canada); Lariviere, R. [Hydro-Quebec, Montreal, PQ (Canada); Cote, P. [Hydro-Quebec Production, Baie-Comeau, PQ (Canada)

    2006-07-01

    Irreversible displacements in dams are associated with alkali-aggregate reaction, creep, and other damaging effects that compromise the safety of dams. An identification of the nature of irreversible displacements is needed to predict the future behaviour of dams as well as to select appropriate remedial measures. This paper provided details of a principal component analysis (PCA) used to investigate swelling and small irreversible displacements observed at the Daniel-Johnson dam in Quebec. PCA is a multivariate statistical method that performs the analysis of correlations or covariances between several random variables simultaneously. Three datasets were used: (1) reservoir water level; (2) air temperature; and (3) pendulum displacements. Standard linear regression analyses (HST) were performed for each variable in order to eliminate outliers and replace missing values. The multivariate dataset was then used to perform PCA on the entire dataset as well as on subsets from the original data. Displacement data from pendulums were used in the multivariate statistical analysis in which each component was treated as a separate variable. The comparison of irreversible displacements of the dam from HST analysis and principal component analysis (PCA) indicated that results were consistent with the data. The PCA analysis identified dominant patterns of behaviour and detected 2 distinct components of irreversible deformations arising from creep and swelling of concrete. Results of the study showed that the PCA analysis led to a better understanding of the overall behaviour of the dam and of individual arches and buttresses. It was concluded that the PCA analysis method will help to improve dam safety in addition to more accurately predicting the future behaviour of dams. 6 refs., 2 tabs., 9 figs.

  2. 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.

  3. In-Plane Elastic Buckling of Arch

    Institute of Scientific and Technical Information of China (English)

    剧锦三; 郭彦林

    2002-01-01

    The in-plane elastic buckling behavior of arches is investigated using a new finite-element approach for the nonlinear analysis. The linear buckling, nonlinear primary buckling, and secondary bifurcation buckling behavior of arches are compared taking into account the large deformation and the effects of initial geometric imperfections or perturbations. The theoretical investigation emphasizes the nonlinear secondary bifurcation buckling behavior for a full span uniformly distributed load. The efficiency of compact method for tracing secondary buckling path is shown through several examples. Finally, a new structural design, which prevents the secondary bifurcation buckling by adding some crossed cables across the arch, is proposed to improve the limit load carrying capacity.

  4. Mycotic Aneurysm of the Aortic Arch

    Directory of Open Access Journals (Sweden)

    Ji Hye Seo

    2014-08-01

    Full Text Available A mycotic aneurysm of the thoracic aorta is rare. We report a case of mycotic aneurysm that developed in the aortic arch. An 86-year-old man was admitted with fever and general weakness. Blood culture yielded methicillin-resistant Staphylococcus aureus. Chest X-ray showed an enlarged aortic arch, and computed tomography scan revealed an aneurysm in the aortic arch. The patient was treated only with antibiotics and not surgically. The size of the aneurysm increased rapidly, resulting in bronchial obstruction and superimposed pneumonia. The patient died of respiratory failure.

  5. 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.

  6. Complete interruption of the aortic arch

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sung Hak; Park, In Kyu; Lee, Won Hwa; Kim, Yong Joo; Kang, Duk Sik; Lee, Jong Tae [Kyungpook National University College of Medicine, Taegu (Korea, Republic of)

    1984-09-15

    Complete interrupture of the aortic arch is one of the least common cardiac malformation. In this condition, continuity between the ascending and descending protions of the aorta is not present, and the descending aorta is supplied through a reversing patent ductus arteriosus. In the majority of the patients a ventricular septal defect is present. Authors have experienced a case of the complete interruption of aortic arch, interruption between the left carotid and the left subclavian artery.

  7. Fractionally Integrated Models With ARCH Errors

    OpenAIRE

    Hauser, Michael A.; Kunst, Robert M.

    1993-01-01

    Abstract: We introduce ARFIMA-ARCH models which simultaneously incorporate fractional differencing and conditional heteroskedasticity. We develop the likelihood function and a numerical estimation procedure for this model class. Two ARCH models - Engle- and Weiss-type - are explicitly treated and stationarity conditions are derived. Finite-sample properties of the estimation procedure are explored by Monte Carlo simulation. An application to the Standard & Poor 500 Index indicates existence o...

  8. Allegheny County Dam Locations

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — This dataset shows the point locations of dams in Allegheny County. If viewing this description on the Western Pennsylvania Regional Data Center’s open data portal...

  9. Right circumflex retro-oesophageal aortic arch with coarctation of a high-positioned right arch

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Kyung-Sik; Yong, Hwan Seok; Woo, Ok Hee; Kang, Eun-Young [Korea University Guro Hospital, Department of Radiology, Seoul (Korea); Lee, Joo-Won [Korea University Guro Hospital, Department of Paediatrics, Seoul (Korea)

    2007-06-15

    We present a rare case of right circumflex retro-oesophageal aortic arch with coarctation of a high-positioned right arch. A 7-month-old boy presented with a cardiac murmur. Cardiac situs was normal and there was no evidence of an intracardiac shunt or patent ductus arteriosus. MR aortography revealed a right aortic arch that was high-positioned, tortuous and narrowed. This right aortic arch crossed the midline behind the oesophagus and continued as a left-sided descending aorta. The left common carotid and subclavian arteries arose from a large branching vascular structure that derived from the top of the left-sided descending aorta. The right common carotid artery arose from the ascending aorta. The proximal portion of the right common carotid artery showed very severe stenosis and poststenotic dilatation. The right subclavian artery originated distal to the narrowed and tortuous segment of the aortic arch. (orig.)

  10. 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.

  11. 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.

  12. 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.

  13. 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......, and gives a large positive bending moment below the load and a smaller negative bending moment in the unloaded side. When the Pearl-Chain Bridge concept is compared to other pre-fabricated arch bridge solutions we find a number of advantages when using Pearl-Chain Bridges: Straight elements, combination...

  14. Dilatation of the aneurysmal sac after total arch replacement.

    Science.gov (United States)

    Watanuki, Hirotaka; Ogino, Hitoshi; Matsuda, Hitoshi; Minatoya, Kenji; Sasaki, Hiroaki; Fukuda, Tetsuya; Kitamura, Soichiro

    2008-02-01

    In our institution, total arch replacement for distal arch aneurysms is performed through a median sternotomy with antegrade selective cerebral perfusion. The distal anastomosis to the completely transected descending aorta is made through the aneurysmal sac. We report on three interesting cases presenting late dilatation of the aneurysmal sac due to collateral flow after total arch replacement.

  15. 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...

  16. Dam safety in British Columbia

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, H.M.; Round, R.P.D.

    1978-01-01

    Many dams in British Columbia were built before 1900, and a comprehensive inspection and surveillance program has been developed. The background and implementation of this program are described. Topics discussed include program responsibilities, classification of dams, organization, the dam safety program, and coordination with other agencies. (PMA)

  17. 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.

  18. 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.

  19. Multislice CT angiography of interrupted aortic arch

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Dong Hyun; Goo, Hyun Woo [Asan Medical Center, Department of Radiology and Research Institute of Radiology, Seoul (Korea); Seo, Dong-Man; Yun, Tae-Jin; Park, Jeong-Jun [Asan Medical Center, University of Ulsan College of Medicine, Department of Paediatric Cardiac Surgery, Seoul (Korea); Park, In-Sook; Ko, Jae Kon; Kim, Young Hwee [Asan Medical Center, University of Ulsan College of Medicine, Department of Paediatric Cardiology, Seoul (Korea)

    2008-01-15

    Interrupted aortic arch (IAA) is defined as complete luminal and anatomic discontinuity between the ascending and descending aorta. Because almost all patients with IAA become critically ill during the neonatal period, they should undergo urgent corrective surgery. This clinical urgency necessitates a fast and accurate noninvasive diagnostic method. Although echocardiography remains the primary imaging tool for this purpose, it is not always sufficient for planning surgical correction of IAA, principally due to a limited acoustic window and the inexperience of imagers. In this context, multislice CT angiography is regarded as an appropriate imaging technique complementary to echocardiography because it is fast, accurate, and objective for the diagnosis of IAA. In this article we describe what cardiac radiologists should know about IAA in their clinical practice, including clinicopathological features, CT features with contemporary surgical methods and postoperative complications, and differentiation from coarctation of the aorta and aortic arch atresia. (orig.)

  20. Structural safety evaluation of Karun III Dam and calibration of its finite element model using instrumentation and site observation

    Directory of Open Access Journals (Sweden)

    H. Mirzabozorg

    2014-06-01

    Full Text Available In the present paper, a comprehensive finite element model of Karun III double curvature arch dam is calibrated based on the micro geodesies measurements and instrumentation. Thermal properties of concrete are obtained by transient thermal analysis and the results are compared with those obtained from thermometers. Thermal analysis features include air temperature, water layers temperatures, and the solar radiation on the exposed faces. Structural calibration features include thermal distribution within the dam body, dam self-weight, hydrostatic pressure, and silt load applied on the model of dam–reservoir–foundation system. Finite element model calibration provides updated information related to the current dam status and can be used for further safety evaluations.

  1. 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

  2. USGS Dam Removal Science Database

    Science.gov (United States)

    Bellmore, J. Ryan; Vittum, Katherine; Duda, Jeff J.; Greene, Samantha L.

    2015-01-01

    This database is the result of an extensive literature search aimed at identifying documents relevant to the emerging field of dam removal science. In total the database contains 179 citations that contain empirical monitoring information associated with 130 different dam removals across the United States and abroad. Data includes publications through 2014 and supplemented with the U.S. Army Corps of Engineers National Inventory of Dams database, U.S. Geological Survey National Water Information System and aerial photos to estimate locations when coordinates were not provided. Publications were located using the Web of Science, Google Scholar, and Clearinghouse for Dam Removal Information.

  3. 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.

  4. Accuracy of impressions obtained with dual-arch trays.

    Science.gov (United States)

    Wöstmann, Bernd; Rehmann, Peter; Balkenhol, Markus

    2009-01-01

    This study aimed to analyze the accuracy resulting from dual-arch impressions when compared to conventional impressions in complex preparations (ie, inlay and partial crown). One hundred eighty impressions were made using two different dual-arch trays; conventional trays served as the control. The accuracy of the dies obtained (Fuji-Rock EP, GC Europe) was assessed indirectly from the change of 59 transversal dimensions. Statistical analysis (t test, analysis of variance) revealed that less rigid dual-arch trays performed better than rigid ones. Though the inlay preparation was more difficult to reproduce with dual-arch trays, it can be concluded that the accuracy obtainable with nonrigid dual-arch trays is comparable to impressions taken from full-arch trays.

  5. Asymptotics of the QMLE for General ARCH(q) Models

    DEFF Research Database (Denmark)

    Kristensen, Dennis; Rahbek, Anders Christian

    2009-01-01

    Asymptotics of the QMLE for Non-Linear ARCH Models Dennis Kristensen, Columbia University Anders Rahbek, University of Copenhagen Abstract Asymptotic properties of the quasi-maximum likelihood estimator (QMLE) for non-linear ARCH(q) models -- including for example Asymmetric Power ARCH and log......-ARCH -- are derived. Strong consistency is established under the assumptions that the ARCH process is geometrically ergodic, the conditional variance function has a finite log-moment, and finite second moment of the rescaled error. Asymptotic normality of the estimator is established under the additional assumption...... that certain ratios involving the conditional variance function are suitably bounded, and that the rescaled errors have little more than fourth moment. We verify our general conditions, including identification, for a wide range of leading specific ARCH models....

  6. Aortic arch blunt injury in front-seat passenger.

    Science.gov (United States)

    Türkmen, Nursel; Eren, Bülent; Aydin, Şule Akköse

    2013-10-01

    Aortic arch blunt injury has highly lethal nature. Because the physical examination findings are subtle, immediate medical evaluation is very important. The case was a 72-year-old woman. Massive haemorrhage in the left haemotorax, contusion area in the left lung and a traumatic transection of the distal aortic arch was observed during autopsy. We described intersting autopsy case of aortic arch blunt injury.

  7. Critical thrombotic obstruction of transverse aortic arch in a neonate

    Directory of Open Access Journals (Sweden)

    Karunakar Vadlamudi

    2015-01-01

    Full Text Available A 3-day-old neonate presented with features suggestive of coarctation of aorta. Echocardiography showed a large organized thrombus in the transverse arch causing obstruction to theaortic arch and carotids with partial recanalization. Patient underwent surgical thromboendarterectomy with arch reconstruction. The evaluation did not reveal any hematological abnormalities and suspected to be due to fetal thromboembolism. Patient improved well, and no neurological deficits were observed during follow-up.

  8. Mathematical model of a moment-less arch.

    Science.gov (United States)

    Lewis, W J

    2016-06-01

    This paper presents a mathematical model for predicting the geometrical shapes of rigid, two-pin, moment-less arches of constant cross section. The advancement of this work lies in the inclusion of arch self-weight and the ability to produce moment-less arch forms for any span/rise ratio, and any ratio of uniformly distributed load per unit span, w, to uniformly distributed arch weight per unit arch length, q. The model is used to derive the shapes of two classical 'moment-less' arch forms: parabolic and catenary, prior to demonstrating a general case, not restricted by the unrealistic load assumptions (absence of q, in the case of a parabolic form, or no w, in the case of a catenary arch). Using the same value of span/rise ratio, and w/q>1, the behaviour of the moment-less and parabolic arches under permanent loading, (w+q), is analysed. Results show the former to be developing much lower stresses than its parabolic rival, even when there are relatively small differences in the two geometries; for a medium span/rise ratio of 4 and w/q=2, differences in the parabolic and moment-less arch geometries would, in practical terms, be viewed as insignificant, but the stresses in them are different.

  9. Right aortic arch with coarctation in Chinese children

    Energy Technology Data Exchange (ETDEWEB)

    Ming, Zhu; Aimin, Sun [Shanghai Children' s Medical Center, Department of Radiology, Shanghai (China)

    2008-05-15

    Because of the rarity of right aortic arch coarctation there are few reports of large groups of patients. To characterize the frequency and type of right aortic arch coarctation in a large group of pediatric patients. From June 1997 through May 2007, 11,276 consecutive children with congenital heart disease underwent multidetector CT (MDCT), MRI or angiocardiography examination. All children with a right aortic arch or coarctation were reviewed. Right aortic arch coarctation was found in 11 children representing 0.1% of the total group of 11,276 children, 1.7% of 658 children with native coarctations and 2.3% of 473 children with a right aortic arch. Among the 11 patients, 6 had long-segment narrowing and 7 had an aberrant left subclavian artery. MDCT, MRI and angiocardiography are reliable imaging techniques for the diagnosis of right aortic arch and coarctation. Our findings showed that the pattern of right aortic arch coarctation was different from that of left aortic arch coarctation, suggesting that they are different etiological entities. The pivotal role possibly played by flow dynamics in the development of right aortic arch coarctation is discussed. (orig.)

  10. 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.

  11. 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.

  12. A Binomial Integer-Valued ARCH Model.

    Science.gov (United States)

    Ristić, Miroslav M; Weiß, Christian H; Janjić, Ana D

    2016-11-01

    We present an integer-valued ARCH model which can be used for modeling time series of counts with under-, equi-, or overdispersion. The introduced model has a conditional binomial distribution, and it is shown to be strictly stationary and ergodic. The unknown parameters are estimated by three methods: conditional maximum likelihood, conditional least squares and maximum likelihood type penalty function estimation. The asymptotic distributions of the estimators are derived. A real application of the novel model to epidemic surveillance is briefly discussed. Finally, a generalization of the introduced model is considered by introducing an integer-valued GARCH model.

  13. Application of thermodynamics-based rate-dependent constitutive models of concrete in the seismic analysis of concrete dams

    Directory of Open Access Journals (Sweden)

    Fei LENG

    2008-09-01

    Full Text Available This paper discusses the seismic analysis of concrete dams with consideration of material nonlinearity. Based on a consistent rate-dependent model and two thermodynamics-based models, two thermodynamics-based rate-dependent constitutive models were developed with consideration of the influence of the strain rate. They can describe the dynamic behavior of concrete and be applied to nonlinear seismic analysis of concrete dams taking into account the rate sensitivity of concrete. With the two models, a nonlinear analysis of the seismic response of the Koyna Gravity Dam and the Dagangshan Arch Dam was conducted. The results were compared with those of a linear elastic model and two rate-independent thermodynamics-based constitutive models, and the influences of constitutive models and strain rate on the seismic response of concrete dams were discussed. It can be concluded from the analysis that, during seismic response, the tensile stress is the control stress in the design and seismic safety evaluation of concrete dams. In different models, the plastic strain and plastic strain rate of concrete dams show a similar distribution. When the influence of the strain rate is considered, the maximum plastic strain and plastic strain rate decrease.

  14. The dam design of Three Gorges Project

    Institute of Scientific and Technical Information of China (English)

    Wang Xiaomao; Xu Linxiang; Liao Renqiang

    2011-01-01

    The dam of Three Gorges Project is a concrete gravity dam with the crest elevation of 185 m, the maximum height of 181 m and dam axis length of 2 309.5 m. The dam consists of spillway, powerhouse, non-over flow, ship-lift, temporary ship-lock, left diversion wall and longitudinal cofferdam blocks. Some key techniques relating to dam structure design are presented, including hydraulics of flood discharge structure, dam joint design, layout and structural type of penstock, deep anti-sliding stability of dam foundation, reconstruction of temporary ship-lock and closed drainage and pumping of dam foundation.

  15. Tarbela Dam Project

    Energy Technology Data Exchange (ETDEWEB)

    Khan, B.A. [WAPDA Tarbela Dam Project (Pakistan); Ahmad, W. [Siemens Pakistan Ltd., Islamabad (Pakistan)

    1999-07-01

    Construction of one of the world's largest water resource development project is discussed. The Tarbela project is built on the Indus River, (itself one of the largest rivers of the world) and consists of a 9,000 feet long and 465 feet high earth and rockfill embankment across the entire width of the river with two spillways cutting through the left bank. On the left bank valley there are two auxiliary embankment dams to close the gap. A total of five tunnels, each a mile long, have been constructed for irrigation releases and power generation. Electricity is being generated by two power generating plants constructed on three of these tunnels. They have a generating capacity of 3,478 MW, supplying 40 per cent of all Pakistani demand. Several 'firsts' are identified. For example, the dam is the world's largest, containing over 200 million cubic yards of earth and rock, as are the five tunnels (14 meters in diameter), as well as the outlet gates. The energy release by the water gushing through the five tunnels at maximum level is more than 13 million KW, approximately equivalent to 10 million horsepower. 1 ref.

  16. 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.

  17. 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.

  18. Rock mechanics investigations, design and construction of the Ridracoli dam

    Science.gov (United States)

    Oberti, G.; Bavestrello, F.; Rossi, P. P.; Flamigni, F.

    1986-07-01

    The Ridracoli arch-gravity concrete dam is the major work in a multipurpose project whose main scope is the water supply to 37 communities in the Forlì and Ravenna Provinces. The particular geological and structural characteristics of the foundation rock mass, consisting of a rhythmical alternation of sandstone, silstone and marl, required a wide program of in situ and laboratory investigations in order to obtain a detailed physical and mechanical characterization of the foundation. The design criteria based on the use of a physical and mathematical model are illustrated as well as the limit equilibrium analysis of the stability conditions of the abutments. Particular attention has been devoted to the problem of the excavation stability; excavation methods and stabilizing works are illustrated in detail. The scepage problems are also presented with the description of grouting and drainage works.

  19. Determination of Seepage and Analysis of Earth Dams (Case Study: Karkheh Dam)

    OpenAIRE

    A. Kamanbedast; M. Shahosseini

    2011-01-01

    Because of the increasing trend of building dam throughout Iran; it is necessary to optimize dam buildings and operations. Dam or Hydropower industry has two types of buildings; normally: (1) Concrete dams (2) Embankment (earth) dams. Generally, scientists and engineers use different methods to enhance safety and decrease any errors in calculation due to maintenance of water storage especially hydro structure of the dam. It is necessary to investigate the dam seepage control; commonly use...

  20. 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.

  1. Defect in Posterior Arch of Atlas in Myelomeningocele

    NARCIS (Netherlands)

    G. Blaauw (Gerhard)

    1971-01-01

    textabstractThe posterior arches of the cervical vertebrae of 30 children who died with a myelomeningocele in the lower thoracic, lumbar or sacral region were examined; in 70 per cent of these cases a defect was found in the posterior arch of the atlas, which was bridged by a firm fibrous band. Alté

  2. 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 is spec...

  3. Twin - Arch technique. Revival of the "edgewise -Technique"?

    Directory of Open Access Journals (Sweden)

    Jacob Karp

    2012-01-01

    The SNB – Bracket brings a new dimension into the orthodontic world which is most apparent in extraction cases. Its Teflon – like material has a very low friction coefficient thus, reducing the treatment time considerably. Through the use of low dimensioned arch wires, the Twin – Arch Technique becomes a Light – wire system and simultaneously provides good anchorage and torque control.

  4. 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.

  5. 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.

  6. Full-scale load tests of Pearl-Chain arches

    DEFF Research Database (Denmark)

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

    2017-01-01

    , pre-fabricated, composite, lightweight, concrete deck elements (SL-Decks), that are post-tensioned together into an arch shape. The two Pearl-Chain arches, each with a span of 13m and a rise of 1m, were placed on a post tensioned bearing plate prepared in advance. The aches are tested with load...

  7. 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

  8. Atlantoaxial stabilization using multiaxial C-1 posterior arch screws.

    Science.gov (United States)

    Donnellan, Michael B; Sergides, Ioannis G; Sears, William R

    2008-12-01

    The authors present a novel technique of atlantoaxial fixation using multiaxial C-1 posterior arch screws. The technique involves the insertion of bilateral multiaxial C-1 posterior arch screws, which are connected by crosslinked rods to bilateral multiaxial C-2 pars screws. The clinical results are presented in 3 patients in whom anomalies of the vertebral arteries, C-1 lateral masses, and/or posterior arch of C-1 presented difficulty using existing fixation techniques with transarticular screws, C-1 lateral mass screws, or posterior wiring. The C-1 posterior arch screws achieved solid fixation and their insertion appeared to be technically less demanding than that of transarticular or C-1 lateral mass screws. This technique may reduce the risk of complications compared with existing techniques, especially in patients with anatomical variants of the vertebral artery, C-1 lateral masses, or C-1 posterior arch. This technique may prove to be an attractive fixation option in patients with normal anatomy.

  9. 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.

  10. 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.

  11. 76 FR 12094 - Whitman River Dam, Inc.

    Science.gov (United States)

    2011-03-04

    ... Federal Energy Regulatory Commission Whitman River Dam, Inc. Notice of Application Tendered for Filing.... Applicant: Whitman River Dam, Inc. e. Name of Project: Crocker Dam Hydro Project. f. Location: On the... analysis at this time. n. The Crocker Dam Hydro Project would consist of: (1) The existing...

  12. Landscape Evolution Modelling of naturally dammed rivers

    NARCIS (Netherlands)

    van Gorp, Wouter; Temme, Arnaud J. A. M.; Baartman, Jantiene E. M.; Schoorl, Jeroen M.

    2014-01-01

    Natural damming of upland river systems, such as landslide or lava damming, occurs worldwide. Many dams fail shortly after their creation, while other dams are long-lived and therefore have a long-term impact on fluvial and landscape evolution. This long-term impact is still poorly understood and la

  13. FORMATION AND FAILURE OF NATURAL DAMS.

    Science.gov (United States)

    Costa, John E.; Schuster, Robert L.

    1988-01-01

    Of the numerous kinds of dams that form by natural processes, dams formed from landslides, glacial ice, and late-neoglacial moraines present the greatest threat to people and property. Landslide dams form a wide range of physiographic settings. The most common types of mass movements that form landslide dams are rock and debris avalanches; rock and soil slumps and slides; and mud, debris, and earth flows. The most common initiation mechanisms for dam-forming landslides are excessive rainfall and snowmelt and earthquakes. Natural dams may cause upstream flooding as the lake rises and downstream flooding as a result of failure of the dam. Although data are few, for the same potential energy at the dam site, downstream flood peaks from the failure of glacier-ice dams are smaller than those from landslide, moraine, and constructed earth-fill and rock-fill dam failures.

  14. Description of dental arch form using the Fourier series.

    Science.gov (United States)

    Valenzuela, A Patricia; Pardo, Marco A; Yezioro, Salomon

    2002-01-01

    The aim of this study was to describe the form of the human superior dental arch using Fourier transformations. Forty models made in dental stone from impressions of the maxillary dental arch were used to obtain the reference data, which were expressed in Cartesian coordinates, from the mesovestibular cuspid vertices of molar teeth, vestibular cuspid of premolars, and incisal edge. Fourth-grade equations and Fourier series were calculated from these data. The results indicate that Fourier series more precisely express the form and size of different dental arches, with mixed or permanent dentition, than fourth-grade equations. Details of the mathematical procedure and the precision obtained were provided.

  15. 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.

  16. A comparative study of inter-abutment distance of dies made from full arch dual-arch impression trays with those made from full arch stock trays: An in vitro study

    Directory of Open Access Journals (Sweden)

    Reddy Jagan

    2009-01-01

    Full Text Available Objectives: The dual-arch impression technique is convenient in that it makes the required maxillary and mandibular impressions, as well as the inter-occlusal record in one procedure. The accuracy of inter-abutment distance in dies fabricated from dual-arch impression technique remains in question because there is little information available in the literature. Materials and Methods: This study was conducted to evaluate the accuracy of inter-abutment distance in dies obtained from full arch dual-arch trays with those obtained from full arch stock metal trays. Results and Conclusion: The metal dual-arch trays showed better accuracy followed by the plastic dual-arch and stock dentulous trays, respectively, though statistically insignificant. The pouring sequence did not have any effect on the inter-abutment distance statistically, though pouring the non-working side of the dual-arch impression first showed better accuracy.

  17. Conflicts Associated with Dam Removal in Sweden

    Directory of Open Access Journals (Sweden)

    Anna G. C. Lejon

    2009-12-01

    Full Text Available The increasing number of deteriorating old dams that need renovation or have lost their function make dam removal a viable management option. There are at least four major reasons for dam removal: safety, law and policy, economy, and ecology. Here we discuss 17 Swedish dams that were recently considered for removal. Because dam removal usually causes controversy, dam removal initiatives may succeed, fail, or result in a compromise such as a bypass channel for migrating fish. We identify and discuss three major obstructions to dam removal: funding, cultural-historical values, and threatened species. To facilitate dam removal, the reasons for, and the effects of, dam removal must be carefully explained, and the public and stakeholders must be kept informed. In complicated cases in which compromise solutions may be the most feasible outcome, the integration of the knowledge of different stakeholders is crucial. The involvement of diverse stakeholders increases their willingness to find compromises, thus avoiding conflicts and failures.

  18. A case of neonatal arterial thrombosis mimicking interrupted aortic arch.

    Science.gov (United States)

    Gürsu, Hazım Alper; Varan, Birgül; Oktay, Ayla; Özkan, Murat

    2015-06-01

    Neonatal arterial thrombosis is a very rare entity with clinical findings resembling coarctation of aorta or interrupted aortic arch. A two day-old male newborn was admitted to a different hospital with difficulty in sucking and sleepiness. On echocardiographic examination, a diagnosis of interrupted aortic arch was made and he was treated with prostoglandin E2. When the patient presented to our center, physical examination revealed that his feet were bilaterally cold. The pulses were not palpable and there were ecchymotic regions in the lower extremities. Echocardiography ruled out interrupted aortic arch. Computerized tomographic angiography revealed a large thrombosis and total occlusion of the abdominal aorta. Since there was no response to treatment with tissue plasminogen activator, we performed thrombectomy. Homozygous Factor V Leiden and Methylenetetrahydrofolate reductase mutations were found in this patient. Neonatal aortic thrombosis which is observed very rarely and fatal should be considered in the differential diagnosis of coarctation of aorta and interrupted aortic arch.

  19. 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....

  20. Dam risk assistant analysis system design

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In order to reduce the labor intensity and task difficulty of dam risk analysis and to meet the actual requirement of dam risk analysis,it is necessary to establish a dam risk assistant analysis system.The program structure and the implementation ways of the dam risk assistant analysis system are analyzed,and a procedural framework with "three-tier and multi-database" structure and "level structure" is established.The concept of dam risk assessment system modular development is proposed and the coupled mode of function module and data is improved.Finally,the dam risk assistant analysis system is developed using Delphi visual programming language.

  1. 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.

  2. Three-dimensional stability analysis of the dam foundation at Baise

    Institute of Scientific and Technical Information of China (English)

    XU Qianjun; LI Xu; CHEN Zuyu

    2007-01-01

    It is usually difficult to determine the actual safety factors of rock masses in an ordinary two-dimensional stability analysis if the safety factors of the different cross sections in the rock mass vary significantly. In addition to the actual slope, arch dam abutment, and the actual foundation of a high building, another example is that the different cross sections of the foundation in the monolith of a gravity dam vary significantly, just like the condition at the overflow dam in the Baise project. A three-dimensional stability analysis method based on the upper-bound theorem was employed to solve this problem. The parameters used in the analysis were obtained from geomechanics tests, as well as continuity simu- lations of the randomly distributed joints. Two failure patterns against sliding are analyzed. One pattern is the foundation slide along deep-seated planes which were determined by cal- culations. The other pattern is the foundation slide along the planes across the bottom of the high steps in the foundation pit. The results indicate that a special overflow dam monolith can be considered to be safe in case of considering the three dimensional effect. However, a key wall with a depth of 5m must be constructed at the upper side of this monolith in order to ensure the safety of the foundation.

  3. Rubber dam use during routine operative dentistry procedures: findings from the dental PBRN.

    Science.gov (United States)

    Gilbert, Gregg H; Litaker, Mark S; Pihlstrom, Daniel J; Amundson, Craig W; Gordan, Valeria V

    2013-04-01

    Rubber dam use during operative dentistry procedures has been quantified based on questionnaires completed by dentists. However, based on the knowledge of the authors of the current study, there are no reports based on use during actual clinical procedures other than in dental materials studies and none based on routine care. The objectives of the current study were to: 1) quantify how commonly the rubber dam is used during operative dentistry procedures; 2) test the hypothesis that certain dentist, restoration and patient-level factors are associated with its use. A total of 229 dentist practitioner-investigators in The Dental Practice-Based Research Network (DPBRN) participated. DPBRN comprises 5 regions: Alabama/Mississippi, Florida/Georgia, Minnesota, Permanente Dental Associates; and Scandinavia. Practitioner-investigators collected data on 9,890 consecutive restorations done in previously unrestored tooth surfaces from 5,810 patients. Most dentists (63%) did not use a rubber dam for any restoration in this study. A rubber dam was used for only 12% of restorations, 83% of which were used in 1 DPBRN region. With regions accounted for, no other dentist characteristics were significant. A multi-level multiple logistic regression of rubber dam use was done with restoration and patient-level variables modeled simultaneously. In this multi-variable context, these restoration-level characteristics were statistically significant: tooth-arch type, restoration classification and reason for placing the restoration. These patient-level characteristics were statistically significant: ethnicity, dental insurance, and age. These results, obtained fromactual clinical procedures rather than questionnaires, document a low prevalence of usage of the rubber dam during operative dentistry procedures. Usage varied with certain dentist, restoration, and patient level characteristics.

  4. Rubber dam use during routine operative dentistry procedures: findings from the Dental PBRN.

    Science.gov (United States)

    Gilbert, Gregg H; Litaker, Mark S; Pihlstrom, Daniel J; Amundson, Craig W; Gordan, Valeria V

    2010-01-01

    Rubber dam use during operative dentistry procedures has been quantified based on questionnaires completed by dentists. However, based on the knowledge of the authors of the current study, there are no reports based on use during actual clinical procedures other than in dental materials studies and none based on routine care. The objectives of the current study were to: 1) quantify how commonly the rubber dam is used during operative dentistry procedures; 2) test the hypothesis that certain dentist, restoration and patient-level factors are associated with its use. A total of 229 dentist practitioner-investigators in The Dental Practice-Based Research Network (DPBRN) participated. DPBRN comprises five regions of the USA: Alabama/Mississippi, Florida/Georgia, Minnesota, Permanente Dental Associates and Scandinavia. Practitioner-investigators collected data on 9,890 consecutive restorations done in previously unrestored tooth surfaces from 5,810 patients. Most dentists (63%) did not use a rubber dam for any restoration in this study. A rubber dam was used for only 12% of restorations, 83% of which were used in one DPBRN region. With regions accounted for, no other dentist characteristics were significant. A multi-level multiple logistic regression of rubber dam use was done with restoration and patient-level variables modeled simultaneously. In this multi-variable context, these restoration-level characteristics were statistically significant: tooth-arch type, restoration classification and reason for placing the restoration. These patient-level characteristics were statistically significant: ethnicity, dental insurance and age. These results, obtained from actual clinical procedures rather than questionnaires, document a low prevalence of usage of the rubber dam during operative dentistry procedures. Usage varied with certain dentist, restoration and patient-level characteristics.

  5. 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.

  6. Comparison of arch forms between Turkish and North American

    Science.gov (United States)

    Celebi, Ahmet A.; Keklik, Hakan; Tan, Enes; 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 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. PMID:27275615

  7. Douglas County Dam Breach Inundation Areas

    Data.gov (United States)

    Kansas Data Access and Support Center — Dam breach analysis provides a prediction of the extent and timing of flooding from a catastrophic breach of the dams. These results are sufficient for developing...

  8. VT High Risk Dam Inundation Areas

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) Preliminary release Storm-Day dam inundation areas digitized from various source Emergency Action Plans. These dams were prioritized for...

  9. Dams and Obstructions along Iowa's Canoe Routes

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — This dataset represents obstruction to canoe and boat users of the canoe routes of Iowa. This may represent actual dams, rock dams (natural or man made), large...

  10. 78 FR 53494 - Dam Safety Modifications at Cherokee, Fort Loudoun, Tellico, and Watts Bar Dams

    Science.gov (United States)

    2013-08-29

    ... Dam Safety Modifications at Cherokee, Fort Loudoun, Tellico, and Watts Bar Dams AGENCY: Tennessee... preferred alternative in its final environmental impact statement (EIS) for the dam safety modifications at Cherokee, Fort Loudoun, Tellico, and Watts Bar Dams. The notice of availability (NOA) of the...

  11. Webinar: Stepped chute design for embankment dams

    Science.gov (United States)

    Changing demographics in the vicinity of dams have led to hazard creep in a number of dams worldwide. Many of these dams now have insufficient spillway capacity as a result of these changes in hazard classification from low to significant or high hazard. Stepped chutes applied to the embankment da...

  12. Dams life; La vie des barrages

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    The paper reports on the conclusions of decennial and annual inspections of French dams. Dams surveillance is performed by the operators and consists in visual examinations and measurements. Concrete dams, in particular, always have more or less developed fissures with water sweating threw the concrete mass or the foundations. Old concrete often show low swelling phenomena which are measured too. (J.S.)

  13. EVALUASI KEAMANAN DAM JATILUHUR BERBASIS INDEKS RESIKO

    Directory of Open Access Journals (Sweden)

    Avazbek Ishbaev

    2014-12-01

    Full Text Available The dams have very important roles to agricultural activities. Especially, West Java with 240,000 hectares of agricultural land, needs a good dam structure that can be used sustainably. Jatiluhur dam in Purwakarta, West Java is one of big dams in Indonesia which has important rules not only for Purwakarta but also for Jakarta, Karawang and Bekasi residents. A study and observation about safety and dam stability is needed to prevent any damage. The purpose of this research were to identify parameters that influenced dam safety and to evaluate dam reliability based on index tools. Analysis was done using risk index tools. The result showed that the condition of the dam of Jatiluhur is still satisfied with indicators, "Idam"-750. The total index risk was 127.22 and the safety factor was 83.04 out of 100. Therefore, Jatiluhur dam could be classified as safe and no need for particular treatments. Jatiluhur dam can be operated in normal condition or abnormal condition with periodic monitoring. Keywords: dam safety, evaluation, Jatiluhur Dam, risk index tools

  14. The formation and failure of natural dams

    Science.gov (United States)

    Costa, J.E.; Schuster, R.L.

    1987-01-01

    Of the numerous kinds of dams that form by natural processes, dams formed from landslides, glacial ice, and neoglacial moraines present the greatest threat to people and property. The most common types of mass movements that form landslide dams are rock and debris avalanches, rock and soil slumps and slides, and mud, debris, and earth flows. The most common initiation mechanisms for dam-forming landslides are excessive rainfall and snowmelt and earthquakes. Landslide dams can be classified into six categories based on their relation with the valley floor. Type I dams (11%) of the 81 landslide dams around the world that were classifed do not reach from one valley side to the other. Type II dams (44%) span the entire valley flood, occasionally depositing material high up on opposite valley sides. Type III dams (41%) move considerable distances both upstream and downstream from the landslide failure. Type IV dams (1%) are rare and involve the contemporaneous failure of material from both sides of a valley. Type V dams (1%) are also rare, and are created when a single landslide sends multiple tongues of debris into a valley forming two or more landslide dams in the same surfaces, that extend under the stream or valley and emerge on the opposite valley side. Many landslide dams fail shortly after formation. Overtopping is by far the most common cause of failure. Glacial ice dams can produce at least nine kinds of ice-dammed lakes. The most dangerous are lakes formed in main valleys dammed by tributary glaciers. Failure can occur by erosion of a drainage tunnel under or through the ice dam or by a channel over the ice dam. Cold polar ice dams generally drain supraglacially or marginally by downmelting of an outlet channel. Warmer temperate-ice dams tend to fail by sudden englacial or subglacial breaching and drainage. Late neoglacial moraine-dammed lakes are located in steep mountain areas affected by the advances and retreats of valley glaciers in the last several

  15. Elastic responses of underground circular arches considering dynamic soil-structure interaction: A theoretical analysis

    Science.gov (United States)

    Chen, Hai-Long; Jin, Feng-Nian; Fan, Hua-Lin

    2013-02-01

    Due to the wide applications of arches in underground protective structures, dynamic analysis of circular arches including soil-structure interactions is important. In this paper, an exact solution of the forced vibration of circular arches subjected to subsurface denotation forces is obtained. The dynamic soil-structure interaction is considered with the introduction of an interfacial damping between the structure element and the surrounding soil into the equation of motion. By neglecting the influences of shear, rotary inertia and tangential forces and assuming the arch incompressible, the equations of motion of the buried arches were set up. Analytical solutions of the dynamic responses of the protective arches were deduced by means of modal superposition. Arches with different opening angles, acoustic impedances and rise-span ratios were analyzed to discuss their influences on an arch. The theoretical analysis suggests blast loads for elastic designs and predicts the potential failure modes for buried protective arches.

  16. [Relationship between aortic arch shape and blood pressure response after coarctation repair].

    Science.gov (United States)

    Ou, P; Mousseaux, E; Auriacombe, L; Pédroni, E; Balleux, F; Sidi, D; Bonnet, D

    2005-01-01

    The mechanisms of secondary hypertension after repair of coarctation of the aorta are not well understood. Abnormalities of the architecture of the aortic arch and their consequences on blood pressure have not been studied. In order to study the relationship between abnormalities or aortic arch architecture and resting blood pressure ninety-four patients without re-coarctation were followed up prospectively from 1997 to 2004 (mean age 16.9 +/- 8.1 years; mean weight 57.5 +/- 18.3 Kg; interval since surgery 16.3 +/- 5.4 years). All underwent MRI angiography of the thoracic aorta which enabled the abnormalities to be classified in 3 groups: gothic arch, crenellated arch and roman arch. Twenty-four patients (25.5%) were hypertensive and 70 (74.4%) normotensive. There were 40 gothic arches (42.5%). 14 crenellated arches (15%) and 40 roman arches (42.5%). Gothic arches were more commonly observed in the hypertensive patients (18/40, [45%, 95% CI 31-62]) than the crenellated arches (4/14, [28.5%, 95% CI 7-48]) or the roman arches (2/40, [5%, 95% CI 2-12]). Only the gothic arch was independently correlated with hypertension on multivariate analysis. The authors conclude that gothic deformation of the aortic arch is an independent predictive factor of hypertension in patients operated for coarctation with an excellent result on the isthmic region. Patients with a gothic appearance of their aortic arch should be followed up closely.

  17. Characterization of the cephalic arch and location of stenosis

    Science.gov (United States)

    Bennett, Shelby; Hammes, Mary S.; Blicharski, Tom; Watson, Sydeaka; Funaki, Brian

    2015-01-01

    Purpose The purpose of this study is to accurately characterize the cephalic arch segments into four domains and to enable more specific evaluation of cephalic arch stenosis (CAS) and determine the frequency of stenosis in each domain. Methods After Institutional Review Board (IRB) approval, a retrospective chart review was done to define a population of patients receiving hemodialysis who developed CAS as apparent on clinically indicated radiologic imaging. A standardized approach was devised to categorize four domains of the cephalic arch. Domain I was defined as the peripheral portion of the arch and Domain IV was the distal portion of the cephalic vein near termination with the axillary vein. The magnitude of stenosis as measured by percentage was determined and compared in the four domains. Results The most frequent location for stenosis was found in domain IV when compared with domains II or I (p<0.01). The magnitude of stenosis differed across all domains (p<0.001) with the least common place for CAS in domain I. Treatment of CAS included angioplasty in all, thrombectomy in eight, and stent placement in five. Conclusions CAS occurs most commonly in the terminal portion of the arch. Four standardized domains have been defined; future work will validate these findings and determine the best intervention for each domain. PMID:25198819

  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 (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.

  19. Classification of the height and flexibility of the medial longitudinal arch of the foot

    DEFF Research Database (Denmark)

    Nilsson, Mettte Kjaergaard; Friis, Rikke; Michaelsen, Maria Skjoldahl

    2012-01-01

    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......-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 study are important for investigating a possible link between arch height and arch movement and the development of injuries....

  20. Future directions of dam safety in Canada

    Energy Technology Data Exchange (ETDEWEB)

    Verzeni, Gerard [Hydro Quebec, QC, (Canada)

    2010-07-01

    Gerard Verzeni, former director of the dam safety & environment at Hydro-Quebec introduced the future directions of dam safety in Canada. New and numerous challenges are emerging for the dam safety community. Measurable effects of climate changes illustrate that hydraulic forecasts would change drastically. Loads with times and amplitudes which are different from the actual knowledge will apply on dams. The development of new types of dams using recent technologies raises several issues, for example the longevity of such installations. The installations are becoming old and soon will require complete renovation and update for regulation and standards compliance. Concrete dams already need efforts and investment to maintain then in a safe state. Various factors will influence these challenges such as human resources in the dam safe community. In these conditions, it is important that organizations like CDA play an important role in providing support and reference and in being a driver for the whole industry.

  1. 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.

  2. 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.

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

    KAUST Repository

    Hafiz, Md Abdullah Al

    2016-10-18

    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.

  4. 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)

  5. 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.

  6. 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.

  7. Full-arch milled titanium implant bridge: technical report.

    Science.gov (United States)

    Peché, Wendy-Ann; Van Vuuren, Ludwig Jansen; Park, Chae

    2011-09-01

    The manufacturing of full-arch fixed implant-supported bridges with the use of the traditional lost wax technique remains a technical challenge. Distortion of the alloy during casting and subsequent heating cycles during porcelain build-up causes numerous problems. Fracturing of porcelain on large restorations is difficult and costly to restore. The fitting problems can be eliminated by utilising CAD/CAM technology in the manufacturing of long-span or full-arch titanium bridges. Repair of damaged porcelain can be simplified with the use of discrete, individually-removable crowns on the bridge.

  8. Aneurysm of the superficial palmar arch: a case report.

    Science.gov (United States)

    Estrella, Emmanuel P; Lee, Ellen Y

    2008-01-01

    Aneurysms of the hand are uncommon lesions. The most common location is the ulnar artery. We present a case of a young female who consulted us for a hand mass with a history of trauma to the hand. Pre-operative arteriogram showed a superficial palmar arch aneurysm. The mass was excised and the arch was reconstructed using a reversed Y-shaped vein graft. Fourteen months after surgery, there was no recurrence of the aneurysm and the patient only reported occasional cold intolerance.

  9. Numerical study of free-fall arches in hopper flows

    Science.gov (United States)

    Lin, P.; Zhang, S.; Qi, J.; Xing, Y. M.; Yang, L.

    2015-01-01

    Beverloo's law describes the flow rate of grains discharging from hoppers, where the assumption of a free-fall arch (FFA) is very useful in understanding the physical picture of this process. The FFA has been observed in previous experiments but a clear systematic study of the FFA is still necessary. In this paper, dense granular flow in hoppers was studied by numerical simulations, in attempts to explore the free-fall region and its boundary. Generally, the numerical simulation results support the free-fall arch assumption, although the statistical description of the FFA is not exactly equivalent to its strict definition.

  10. 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.

  11. 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.

  12. 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.

  13. 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 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.

  14. ArchDB 2014: structural classification of loops in proteins

    Science.gov (United States)

    Bonet, Jaume; Planas-Iglesias, Joan; Garcia-Garcia, Javier; Marín-López, Manuel A.; Fernandez-Fuentes, Narcis; Oliva, Baldo

    2014-01-01

    The function of a protein is determined by its three-dimensional structure, which is formed by regular (i.e. β-strands and α-helices) and non-periodic structural units such as loops. Compared to regular structural elements, non-periodic, non-repetitive conformational units enclose a much higher degree of variability—raising difficulties in the identification of regularities, and yet represent an important part of the structure of a protein. Indeed, loops often play a pivotal role in the function of a protein and different aspects of protein folding and dynamics. Therefore, the structural classification of protein loops is an important subject with clear applications in homology modelling, protein structure prediction, protein design (e.g. enzyme design and catalytic loops) and function prediction. ArchDB, the database presented here (freely available at http://sbi.imim.es/archdb), represents such a resource and has been an important asset for the scientific community throughout the years. In this article, we present a completely reworked and updated version of ArchDB. The new version of ArchDB features a novel, fast and user-friendly web-based interface, and a novel graph-based, computationally efficient, clustering algorithm. The current version of ArchDB classifies 149,134 loops in 5739 classes and 9608 subclasses. PMID:24265221

  15. 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.

  16. 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.

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

    Science.gov (United States)

    Habertheuer, Andreas; Wiedemann, Dominik; Kocher, Alfred; Laufer, Guenther; Vallabhajosyula, Prashanth

    2015-01-01

    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. PMID:26713319

  18. THE ETIOLOGICAL FACTORS INVOLVED IN DENTAL ARCH PERIMETER SHORTENING

    Directory of Open Access Journals (Sweden)

    Liliana Ioana Vâţă

    2012-12-01

    Full Text Available The main purpose of the study was to highlight the causes that may lead to reduction of arches: early loss of deciduous teeth, with consecutive dental drifting on the arch, followed by narrowing of the space necessary for the eruption of successional teeth, caries of the deciduous teeth or ectopic eruption of the first permanent molars. The mesial position of M1 had a frequency of 19.31% of the total number of analysed cases; maximum frequencies have been registered for the localization on the lower arch; M1 ectopia has rarely occurred on the studied batch; the frequency of lateral group mesial position was of 10.34% on the studied batch, registering maximum values for the localisation on the upper arch. The early loss of deciduous teeth was identified in almost 30% of the analysed cases, while the reduction of the space necessary for the eruption of successional teeth was registered in almost 39% of cases, space narrowing resulting both from the caries of deciduous teeth and from their early loss.

  19. Right-sided aortic arch with Kommerell′s aneurysm

    Directory of Open Access Journals (Sweden)

    Sanjay Orathi Patangi

    2014-01-01

    Full Text Available We present a case report of a 55-year-old lady who presented with progressive dysphagia and was diagnosed with a Kommerell′s aneurysm and a right-sided aortic arch. This case report outlines our management strategy and the challenges encountered during the perioperative period in a patient with this rare anomaly.

  20. 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.

  1. Arch Venture Partners' investment considerations for CBRNE products and opportunities

    Science.gov (United States)

    Crandell, K.; Lazarus, S.; Gardner, P. J.

    2008-04-01

    ARCH is interested in building leading, highly-valued companies from leading research. Toward that end we value innovations created by the leading researchers in the world, many of which are funded to solve critical scientific challenges including those in the instrumentation and CBRNE area. The most important CBRNE innovations we have seen at ARCH are breakthroughs involving significant unaddressed technology risk and have the potential for broad proprietary intellectual property as a result. The model ARCH has evolved in instrumentation is to look for a breakthrough innovation, with strong intellectual property and continue to strengthen the patent estate through the life of the company. ARCH looks to build companies around leading interdisciplinary scientific and engineering teams, and we favor platform technology that can be applied to multiple market applications both commercial and government. As part of a strategy to build a great company, addressing important CBRNE challenges can help a company strengthen its technical team and its IP estate. This supports a focus on early low volume markets on the way toward addressing a fuller portfolio of applications. Experienced Venture Capitalists can help this process by identifying important executive talent, partners and applications, offering financial syndication strength, and helping shape the company's strategy to maximize the ultimate value realized.

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    Lifescience Database Archive (English)

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  8. Exporting dams: China's hydropower industry goes global.

    Science.gov (United States)

    McDonald, Kristen; Bosshard, Peter; Brewer, Nicole

    2009-07-01

    In line with China's "going out" strategy, China's dam industry has in recent years significantly expanded its involvement in overseas markets. The Chinese Export-Import Bank and other Chinese financial institutions, state-owned enterprises, and private firms are now involved in at least 93 major dam projects overseas. The Chinese government sees the new global role played by China's dam industry as a "win-win" situation for China and host countries involved. But evidence from project sites such as the Merowe Dam in Sudan demonstrates that these dams have unrecognized social and environmental costs for host communities. Chinese dam builders have yet to adopt internationally accepted social and environmental standards for large infrastructure development that can assure these costs are adequately taken into account. But the Chinese government is becoming increasingly aware of the challenge and the necessity of promoting environmentally and socially sound investments overseas.

  9. Dam Inventory, dams, Published in 2009, 1:24000 (1in=2000ft) scale, Washington County.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Dam Inventory dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Other information as of 2009. It is described as 'dams'. Data...

  10. Dam safety review, classification of dams for the Novia Scotia Power Inc. Black River hydroelectric system

    Energy Technology Data Exchange (ETDEWEB)

    Alderman, Aaron; Small, Andy [AMEC Earth and environmental, Fredericton, (Canada); O' Neil, Ellis [Nova Scotia Power Inc., Halifax, (Canada)

    2010-07-01

    In 2009, AMEC was retained by Nova Scotia Power Inc. (NSPI) to conduct a dam safety review of the dams that are part of the Black River Hydroelectric System. This paper presented the results of this dam classification exercise which was carried out for the Bear River hydroelectric system in Nova Scotia, based on the 2007 Canadian Dam Association (CDA) dam safety guidelines. Flood mapping and dam-break analysis were performed for events ranging from the 1:100 year to PMF flood events, including cascading events. These results were used to draw up a classification of the dams. Associated design criteria were then developed. Following the assessment of the dam sites, conclusions and recommendations were discussed. The recommendations were presented in terms of regular maintenance items and reconstruction items, which are now used by NSPI to determine the party responsible for undertaking the recommendation and for evaluation of the maintenance and reconstruction schedules.

  11. CREATIVITY METHODS IN TEACHING THE ARCH-DESIGN STUDIO

    Directory of Open Access Journals (Sweden)

    EIGBEONAN Andrew B.

    2013-07-01

    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.

  12. Study on dynamic anti-sliding stability of a high gravity dam considering complex dam foundation

    OpenAIRE

    Deng-hong CHEN; Cheng-bin DU

    2011-01-01

    There existed some limitations when analyzing the anti-sliding seismic stability of dam-foundation system by traditional pseudo-static method and response spectrum method. The dynamic strength reduction method was used to study on the deep anti-sliding stability of a high gravity dam considering complex dam foundation under strong earthquake-induced ground action. The static analysis was firstly carried out by reducing the shear strength parameters of the dam foundation’s rock mass with equal...

  13. Measurement of Dam Deformations: Case Study of Obruk Dam (Turkey)

    Science.gov (United States)

    Gulal, V. Engin; Alkan, R. Metin; Alkan, M. Nurullah; İlci, Veli; Ozulu, I. Murat; Tombus, F. Engin; Kose, Zafer; Aladogan, Kayhan; Sahin, Murat; Yavasoglu, Hakan; Oku, Guldane

    2016-04-01

    In the literature, there is information regarding the first deformation and displacement measurements in dams that were conducted in 1920s Switzerland. Todays, deformation measurements in the dams have gained very different functions with improvements in both measurement equipment and evaluation of measurements. Deformation measurements and analysis are among the main topics studied by scientists who take interest in the engineering measurement sciences. The Working group of Deformation Measurements and Analysis, which was established under the International Federation of Surveyors (FIG), carries out its studies and activities with regard to this subject. At the end of the 1970s, the subject of the determination of fixed points in the deformation monitoring network was one of the main subjects extensively studied. Many theories arose from this inquiry, as different institutes came to differing conclusions. In 1978, a special commission with representatives of universities has been established within the FIG 6.1 working group; this commission worked on the issue of determining a general approach to geometric deformation analysis. The results gleaned from the commission were discussed at symposiums organized by the FIG. In accordance with these studies, scientists interested in the subject have begun to work on models that investigate cause and effect relations between the effects that cause deformation and deformation. As of the scientist who interest with the issue focused on different deformation methods, another special commission was established within the FIG engineering measurements commission in order to classify deformation models and study terminology. After studying this material for a long time, the official commission report was published in 2001. In this prepared report, studies have been carried out by considering the FIG Engineering Surveying Commission's report entitled, 'MODELS AND TERMINOLOGY FOR THE ANALYSIS OF GEODETIC MONITORING OBSERVATIONS

  14. 78 FR 60271 - Hollow Dam Power Company; Ampersand Hollow Dam Hydro, LLC; Notice of Application for Transfer of...

    Science.gov (United States)

    2013-10-01

    ... Federal Energy Regulatory Commission Hollow Dam Power Company; Ampersand Hollow Dam Hydro, LLC; Notice of..., Hollow Dam Power Company (transferor) and Ampersand Hollow Dam Hydro, LLC (transferee) filed an application for transfer of license for the Hollow Dam Project, FERC No. 6972, located on the West Branch...

  15. Debris Flow Dam Formation in Southeast Tibet

    Institute of Scientific and Technical Information of China (English)

    CHENG Zunlan; WU Jishan; GENG Xueyong

    2005-01-01

    Glaciers with their deposits abound in the alpine areas of Southeast Tibet. Large debris flows occur frequently from these deposits and form dams that block streams. In this paper, 3 events of large debris flows reported in Peilong Valley located in Southeast Tibet, and which resulted 2 blocking dams resulted, are discussed in details, focusing on the major factors controlling dam formation. The results shows that the first surge group caused by snow and ice avalanches, ice-lake breaks, and large-scale landslides, with a high peak discharge and high velocity, and an abundance of boulders, are most likely to form blocking dams.

  16. Comprehensive evaluation methods for dam service status

    Institute of Scientific and Technical Information of China (English)

    WU ZhongRu; XU Bo; GU ChongShi; LI ZhanChao

    2012-01-01

    More than 87000 dams have been built in China,and about one third of them are risky projects.A number of high and ultra-high dams are being constructed in China's western region.The current dam construction practice tends to focus on socio-economic benefits and neglect the environment and ecology.Furthermore,periodic examinations are intended to ensure the structural safety of dams.This paper proposes a general evaluation principle for dam service.This principle stipulates that dam projects should have maximum socio-economic benefits and minimum negative effects on the environment and ecology.To satisfy the general principle of mutual harmony,socio-economic benefits,dam safety,environment,and ecology are analyzed,and the evaluation methods for dam service status are discussed.Then,a fusion algorithm of interlayer assessment is proposed on the basis of evidence theory and the fuzzy comprehensive analysis method.Finally,a comprehensive evaluation model is established.Example analysis shows that the proposed theories and methods can fulfill scientific assessment of the service status of dams.

  17. 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

  18. 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.

  19. 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.

  20. Safety Aspects of Sustainable Storage Dams and Earthquake Safety of Existing Dams

    Directory of Open Access Journals (Sweden)

    Martin Wieland

    2016-09-01

    Full Text Available The basic element in any sustainable dam project is safety, which includes the following safety elements: ① structural safety, ② dam safety monitoring, ③ operational safety and maintenance, and ④ emergency planning. Long-term safety primarily includes the analysis of all hazards affecting the project; that is, hazards from the natural environment, hazards from the man-made environment, and project-specific and site-specific hazards. The special features of the seismic safety of dams are discussed. Large dams were the first structures to be systematically designed against earthquakes, starting in the 1930s. However, the seismic safety of older dams is unknown, as most were designed using seismic design criteria and methods of dynamic analysis that are considered obsolete today. Therefore, we need to reevaluate the seismic safety of existing dams based on current state-of-the-art practices and rehabilitate deficient dams. For large dams, a site-specific seismic hazard analysis is usually recommended. Today, large dams and the safety-relevant elements used for controlling the reservoir after a strong earthquake must be able to withstand the ground motions of a safety evaluation earthquake. The ground motion parameters can be determined either by a probabilistic or a deterministic seismic hazard analysis. During strong earthquakes, inelastic deformations may occur in a dam; therefore, the seismic analysis has to be carried out in the time domain. Furthermore, earthquakes create multiple seismic hazards for dams such as ground shaking, fault movements, mass movements, and others. The ground motions needed by the dam engineer are not real earthquake ground motions but models of the ground motion, which allow the safe design of dams. It must also be kept in mind that dam safety evaluations must be carried out several times during the long life of large storage dams. These features are discussed in this paper.

  1. 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.

  2. Adaptability to geological faulted foundation of Hardfill dam

    Institute of Scientific and Technical Information of China (English)

    Kun XIONG; Yunlong HE; Yunfeng PENG

    2008-01-01

    Hardfill dam is a new type of dam which has the advantages of low stress level and even stress distri-bution in a dam body, resulting in low demands to foun-dations. Based on 2D linear elastic and elasto-plastic calculations of gravity dam and Hardfill dam using finite element method (FEM), the stress distribution in a dam body and anti-sliding stabilization is analyzed on the geo-logical faulted foundations with weak weathered rock and soft interlayers. It is concluded that Hardfill dams have better adaptability to geological faulted foundations than gravity dams and is more secure and economically sound.

  3. McNary Dam, Ice Harbor Dam, and Lower Monumental Dam Smolt Monitoring Program; 1996 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Hillson, Todd; Lind, Sharon; Price, William (Washington Department of Fish and Wildlife, Olympia, WA)

    1997-07-01

    The Washington Department of Fish & Wildlife (WDFW) assumed responsibility for the Smolt Monitoring Program at McNary Dam on the Columbia River in 1990 and at the new juvenile collection facility at Lower Monumental Dam on the Snake River in 1993. In 1996, Smolt Monitoring Program activities also began at the new juvenile collection facility located at Ice Harbor Dam. This report summarizes the 1996 Smolt Monitoring work at all three sites. The work at Ice Harbor consisted of Gas Bubble Trauma (GBT) monitoring only. In general, the 1996 passage season at both the McNary and Lower Monumental sites can be characterized by reduced passage of juveniles through the collection systems due to elevated river flows and spill, and low (<1%) overall facility mortality rates most likely resulting from cooler water temperatures. In accordance with the National Marine Fisheries Service recommendations (NMFS, 1995) all spring migrants were bypassed at McNary Dam in 1996. Mechanical problems within the McNary collection system resulted in collection and sampling activities being delayed until April 18 at this site, while sampling and collection began on the scheduled starting date of April 1 at Lower Monumental Dam. Monitoring operations were conducted through December 14 at McNary Dam and through October 28 at Lower Monumental Dam. An ongoing transportation evaluation summer migrant marking program was conducted at McNary Dam in 1996 by the NMFS. This necessitated the sampling of 394,211 additional fish beyond the recommended sampling guidelines. All total, 509,237 and 31,219 juvenile salmonids were anesthetized and individually counted, examined for scale loss, injuries, and brands by WDFW Smolt Monitoring personnel in 1996 at McNary Dam and Lower Monumental Dam, respectively.

  4. Vulnerability of aged concrete gravity dams

    Energy Technology Data Exchange (ETDEWEB)

    Gogoi, I. [Assam Engineering Institute, Guwahati (India). Dept. of Civil Engineering; Maity, D. [Indian Institute of Technology, Guwahati (India). Dept. of Civil Engineering

    2004-07-01

    This paper presented an analysis procedure to predict the effects of aging on the behavior of concrete gravity dams. A time dependent isotropic damage index was determined, presenting the performance of the dam with increasing age. Results revealed that the degradation process is dependent on the design life of the structure. The influence of damage along the dam height was greater than damage observed along its width. In order to consider the time dependent degradation of concrete owing to environmental factors and mechanical loading, an algorithm was presented in order to forecast the behavior of existing dams and to assess the necessity of retrofitting or decommissioning. It was concluded that dam behavior during seismic excitation is influenced by the effects of both the dam reservoir system and initial earthquake damage. With increasing age, dam displacement increases, but hydrodynamic pressures and stresses exerted by reservoirs decrease. It was recommended that more accurate behavior could be determined if further research into the coupled effect of foundation-dam-reservoir interaction with material non-linearity was considered. 15 refs.,15 figs.

  5. Restoring Environmental Flows by Modifying Dam Operations

    Directory of Open Access Journals (Sweden)

    Gregory A. Thomas

    2007-06-01

    Full Text Available The construction of new dams has become one of the most controversial issues in global efforts to alleviate poverty, improve human health, and strengthen regional economies. Unfortunately, this controversy has overshadowed the tremendous opportunity that exists for modifying the operations of existing dams to recover many of the environmental and social benefits of healthy ecosystems that have been compromised by present modes of dam operation. The potential benefits of dam "re-operation" include recovery of fish, shellfish, and other wildlife populations valued both commercially and recreationally, including estuarine species; reactivation of the flood storage and water purification benefits that occur when floods are allowed to flow into floodplain forests and wetlands; regaining some semblance of the naturally dynamic balance between river erosion and sedimentation that shapes physical habitat complexity, and arresting problems associated with geomorphic imbalances; cultural and spiritual uses of rivers; and many other socially valued products and services. This paper describes an assessment framework that can be used to evaluate the benefits that might be restored through dam re-operation. Assessing the potential benefits of dam re-operation begins by characterizing the dam's effects on the river flow regime, and formulating hypotheses about the ecological and social benefits that might be restored by releasing water from the dam in a manner that more closely resembles natural flow patterns. These hypotheses can be tested by implementing a re-operation plan, tracking the response of the ecosystem, and continually refining dam operations through adaptive management. The paper highlights a number of land and water management strategies useful in implementing a dam re-operation plan, with reference to a variety of management contexts ranging from individual dams to cascades of dams along a river to regional energy grids. Because many of the

  6. Upgrading of Boundary Dam spillway

    Energy Technology Data Exchange (ETDEWEB)

    McPhail, Gordon; MacMillan, Dave; Smith, Bert [KGS Group, Winnipeg, (Canada); Lacelle, Justin [SaskPower, Regina, (Canada)

    2010-07-01

    An initial dam safety review was performed in 2005 and identified a number of concerns; the most critical were insufficient spillway capacity and deficiencies in the condition of the existing spillways. This paper described the challenges faced by the upgrading operation on the 50 year old Boundary Dam spillway started in 2008. SaskPower retained the KGS Group to increase the design spillway capacity to 1200 m3/s and remedy observed defects. The construction project involved maintaining the reservoir at full supply level while the 20m long spillway chute and stilling basin below were completely replaced. The difficulties came from the need to complete each year's construction such that the spillway could potentially pass spring flood flows. This paper showed that the upgrade measures selected for implementation were developed through close dialogue between the owner and the designer, with valuable input provided by a panel of external experts as well as from contractors participating in the design process.

  7. 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...

  8. 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.

  9. Research progress on dam-break floods

    KAUST Repository

    Wu, Jiansong

    2011-08-01

    Because of the catastrophic effects downstream of dam-break failure, more and more researchers around the world have been working on the study of dam-break flows to accurately forecast the downstream inundation mapping. With the rapid development of computer hardware and computing techniques, numerical study on dam-break flows has been a popular research subject. In the paper, the numerical methodologies used to solve the governing partial differential equations of dam-break flows are classified and summarized, and their characteristics and applications are discussed respectively. Furthermore, the fully-developed mathematical models developed in recent decades are reviewed, and also introduced the authors\\' on-going work. Finally, some possible future developments on modeling the dam-break flows and some solutions are presented and discussed. © 2011 IEEE.

  10. Congenital absence of the atlas posterior arch. A case report.

    Science.gov (United States)

    Huggare, J

    1995-02-01

    A report of a healthy young adult woman with non-pathological congenital absence of the lateral and posterior parts of the atlas is presented. This occurred in association with a steep mandibular plane angle and an extremely obtuse gonial angle. Similar facial features are common in females with hypoplastic dorsal arches, and this case illustrates the intimate developmental association between the upper part of the cervical spine and the craniofacial complex.

  11. Double arch mirror study. Part 3: Fabrication and test report

    Science.gov (United States)

    Vukobratovich, D.; Hillman, D.

    1983-01-01

    A method of mounting a cryogenically cooled, lightweight, double arch, glass mirror was developed for infrared, astronomical telescopes such as the Space Infrared Telescope Facility (SIRTF). A 50 cm, fused silica mirror which was previously fabricated was modified for use with a new mount configuration. This mount concept was developed. The modification of the mirror, the fabrication of the mirror mount, and the room temperature testing of the mounted mirror are reported. A design for a SIRTF class primary mirror is suggested.

  12. Hemiarthroplasty for proximal humeral fracture: restoration of the Gothic arch.

    Science.gov (United States)

    Krishnan, Sumant G; Bennion, Phillip W; Reineck, John R; Burkhead, Wayne Z

    2008-10-01

    Proximal humerus fractures are the most common fractures of the shoulder girdle, and initial management of these injuries often determines final outcome. When arthroplasty is used to manage proximal humeral fractures, surgery remains technically demanding, and outcomes have been unpredictable. Recent advances in both technique and prosthetic implants have led to more successful and reproducible results. Key technical points include restoration of the Gothic arch, anatomic tuberosity reconstruction, and minimal soft tissue dissection.

  13. Do we need construct more dams?

    Science.gov (United States)

    Chen, J.; Shi, H.

    2013-12-01

    This paper reviews global dam development in association with the growths of global population, economy, and energy consumption in the past several decades, and also evaluates contributions of dam development to future world sustainable development. Eventually, this paper answers whether we need more dams in the future or not. The world population has rapidly increased from 1.6 billion in 1900, 2.5 billion in 1950, 6.1 billion in 2000, to 7.0 billion in 2011, and is projected to reach 9.5 billion in 2050; similarly, the world economy has dramatically expanded. To maintain socioeconomic development, the consumption of water, food and energy has increased rapidly as well. However, the total volume of available water resource over the world is limited, the food production largely depends on water supply, and the main energy sources are still oil, coal and gas at present, which are regarded as non-renewable resources. Accordingly, it is expected that we will face serious problems to deal with the challenges of water crisis, food security and energy shortage in the near future. In order to enhance the capability of regulating water resource, a great number of global dams (and related reservoirs) have been constructed in the last one hundred years; currently, almost all large rivers over the world have been regulated by dams. The reservoirs can supply sufficient water for irrigated land to ensure food production, and the associated hydropower stations can generate electricity. This article collects the dam data from the ICOLD (International Commission on Large Dams) and GRanD (Global Reservoir and Dam) databases, and some socioeconomic data, including population, economy, and consumptions of water, food and energy over the world. Analysis of these data reveals that global dam development has a great impact on the world sustainable development. Further, it is concluded that we need further dam development to maintain our future development.

  14. Seismic failure modes and seismic safety of Hardfill dam

    Institute of Scientific and Technical Information of China (English)

    Kun XIONG; Yong-hong WENG; Yun-long HE

    2013-01-01

    Based on microscopic damage theory and the finite element method, and using the Weibull distribution to characterize the random distribution of the mechanical properties of materials, the seismic response of a typical Hardfill dam was analyzed through numerical simulation during the earthquakes with intensities of 8 degrees and even greater. The seismic failure modes and failure mechanism of the dam were explored as well. Numerical results show that the Hardfill dam remains at a low stress level and undamaged or slightly damaged during an earthquake with an intensity of 8 degrees. During overload earthquakes, tensile cracks occur at the dam surfaces and extend to inside the dam body, and the upstream dam body experiences more serious damage than the downstream dam body. Therefore, under the seismic conditions, the failure pattern of the Hardfill dam is the tensile fracture of the upstream regions and the dam toe. Compared with traditional gravity dams, Hardfill dams have better seismic performance and greater seismic safety.

  15. ON THE CYTOTOXICITY OF ORTHODONTIC ARCHES IN HUMAN FIBROBLAST CULTURES

    Directory of Open Access Journals (Sweden)

    Liliana-Gabriela HALIŢCHI

    2015-12-01

    Full Text Available The present study analyzes the orthodontic nickel-titanium alloy with orthodontic shape memory (Niti GAC arches, Nitinol 3M arches, Beta Titanium 3M arches from the viewpoint of its cytotoxicity. Apart from the intrinsic toxicity of the metals upon cells, corrosion may dramatically alter the behaviour of alloys, as evidenced by the in vitro and in vivo studies developed in the field. Due to the high and variable nickel content, its is possible that, at least theoretically, the released ions should produce – as a result of intraoral corrosion – secondary effects, which makes necessary to assert the cytotoxicity of NiTi alloys prior to their safe utilizationor in the oral cavity of children and young patients. Evaluation of cell morphology and determination of cell viability, following exposure to the 3 types of orthodontic materials, evidenced no toxic reactions. Several problems are still to be elucidated, related to the consequences of the surface conditions, of the dissolution and in vivo release of the nickel ions after a longer treatment, of the accumulations of ion traces, of the response of the dental-periodontal tissues, of the effects manifested at cell and molecular level. Apart from the intrisic toxicity of metals upon cells, corrosion may dramatically influence the behaviour of alloys under in vitro conditions, comparatively with the in vivo ones, the nitinol samples being biologically safe.

  16. 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.

  17. 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.

  18. 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.)

  19. 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

  20. 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.

  1. Effect of aging on the configurational change of the aortic arch

    Directory of Open Access Journals (Sweden)

    Atsuhiro Kojima

    2016-04-01

    Full Text Available We explored the relationship between aging and the configuration of the aortic arch using computed tomography angiography (CTA. We retrospectively reviewed CTA obtained in 140 cases. The configuration of the aortic arch was categorized into three types based on the criteria mentioned by Madhwal et al., and the relationships between each configuration and patient characteristics were analyzed. Anomalies of the aortic arch were also explored. Twenty patients had a type-1 aortic arch (mean age, 56.1 years, 30 patients had a type-2 aortic arch (mean age, 66.3 years, and 89 patients had a type-3 aortic arch (mean age, 71.7 years. The mean age of patients with a type-3 aortic arch was significantly higher than that of patients with a type-1 aortic arch. No significant correlations between the type of aortic arch and other factors, such as smoking habit, were seen. The configuration of the aortic arch in our study appears to be significantly affected by the age of the patients.

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

    Directory of Open Access Journals (Sweden)

    Meldo Mahniza

    2015-06-01

    Full Text Available 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 circumference. Pearson correlation showed a weak association for anterior arch width (r=0.206, posterior arch width (r=0.195, and anterior circumference (r=0.206 of maxilla and posterior arch width (r=0.279, anterior circumference (r=0.226 of mandible. One-way Anova was performed to analyze the differences of dental arch measurements among duration of bottle-feeding groups. The results showed that there were significant differences of dental arch measurements for anterior arch width of maxilla, posterior arch width of mandible, and anterior circumference of mandible (p<0,05.

  3. 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].

  4. 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

  5. TYPOLOGY OF LARGE DAMS. A REVIEW

    Directory of Open Access Journals (Sweden)

    Gheorghe ROMANESCU

    2015-06-01

    Full Text Available The dams represent hydrotechnical constructions meant to ensure a judicious use of water resources. The international literature is extremely rich in data regarding the large dams on Earth. In this context, a hierarchy of the main dams is attempted and the role they play in the economic development of the regions they were built in is underlined. The largest dams are built on the big rivers in Asia, North America, South America and Africa. The reservoirs have multiple roles: electricity production, drinking or industrial water supply, irrigations, recreation, etc. High costs and land fragility do not allow the construction of dams in the places most affected by drought or flood. This is why they are usually built in mountainous areas, at great distance from the populated centres. On the Romanian territory, there are 246 large dams, built in the hydrographical basins of Siret, Olt, Arges, Somes, etc. The largest rivers on Earth, by discharge, (Amazon and Zair do not also include the largest dams because the landform and the type of flow have not allowed such constructions.

  6. Nonlinear Seismic Analysis of Morrow Point Dam

    Energy Technology Data Exchange (ETDEWEB)

    Noble, C R; Nuss, L K

    2004-02-20

    This research and development project was sponsored by the United States Bureau of Reclamation (USBR), who are best known for the dams, power plants, and canals it constructed in the 17 western states. The mission statement of the USBR's Dam Safety Office, located in Denver, Colorado, is ''to ensure Reclamation dams do not present unacceptable risk to people, property, and the environment.'' The Dam Safety Office does this by quickly identifying the dams which pose an increased threat to the public, and quickly completing the related analyses in order to make decisions that will safeguard the public and associated resources. The research study described in this report constitutes one element of USBR's research and development work to advance their computational and analysis capabilities for studying the response of dams to strong earthquake motions. This project focused on the seismic response of Morrow Point Dam, which is located 263 km southwest of Denver, Colorado.

  7. Ririe Dam Release Test Assessment

    Science.gov (United States)

    2013-06-01

    72 Lyme Road Hanover, NH 03755-1290 Stephen Hall and Jeremy Giovando US Army Engineer District, Walla Walla 201 North Third Avenue Walla Walla...11/2013 at 0330 2/12/2013 at 1410 10120114 95th St. (1) 10120115 55th St. (2) 2/11/2013 at 1010 2/12/2013 at 2120 10120111 55th St. (1) 9737377...Ririe Dam 2/10/2013 at 1440 0 hr 64,700 N 95th E 2/12/2013 at 1410 47 hr 30 min 0.32 0.32 33,020 55th St. Bridge 2/12/2013 at 2120 54 hr 40 min

  8. The geomorphic legacy of small dams — An Austrian study

    NARCIS (Netherlands)

    Poeppl, R.E.; Keesstra, S.D.; Hein, T.

    2015-01-01

    Dams represent one of the most dominant forms of human impact upon fluvial systems during the Anthropocene, as they disrupt the downstream transfer of water and sediments. Removing dams restores river continuity and channel morphology. Both dam construction and dam removal induce geomorphic channel

  9. Sustainability of dams-an evaluation approach

    Science.gov (United States)

    Petersson, E.

    2003-04-01

    Situated in the stream bed of a river, dams and reservoirs interrupt the natural hydrological cycle. They are very sensitive to all kinds of changes in the catchment, among others global impacts on land use, climate, settlement structures or living standards. Vice versa dams strongly affect the spatially distributed, complex system of ecology, economy and society in the catchment both up- and downstream of the reservoir. The occurrence of negative impacts due to large dams led to serious conflicts about future dams. Nevertheless, water shortages due to climatic conditions and their changes, that are faced by enormous water and energy demands due to rising living standards of a growing world population, seem to require further dam construction, even if both supply and demand management are optimised. Although environmental impact assessments are compulsory for dams financed by any of the international funding agencies, it has to be assumed that the projects lack sustainability. Starting from an inventory of today's environmental impact assessments as an integral part of a feasibility study the presentation will identify their inadequacies with regard to the sustainability of dams. To improve the sustainability of future dams and avoid the mistakes of the past, the planning procedures for dams have to be adapted. The highly complex and dynamical system of interrelated physical and non-physical processes, that involves many different groups of stakeholders, constitutes the need for a model-oriented decision support system. In line with the report of the World Commission of Dams an integrated analysis and structure of the complex interrelations between dams, ecology, economy and society will be presented. Thus the system, that a respective tool will be based on, is analysed. Furthermore an outlook will be given on the needs of the potential users of a DSS and how it has to be embedded in the overall planning process. The limits of computer-based decision-support in the

  10. Mechanical analysis of a gravity dam

    OpenAIRE

    Bergant, Urša

    2012-01-01

    In the first part of our work we will present the water supply project in Obala and backend Karst regions. The use of the river Reka and its tributary Suhorka is essential, since an amassment is going to be built on it. We decided to build the dam from rolled concrete, which is economically and environmentally better than a paved barrier or a classic concrete dam. The second part of our work includes tension and stability program calculations. The primary dimensions of the dam-taken from a te...

  11. Reliablity analysis of gravity dams by response surface method

    Science.gov (United States)

    Humar, Nina; Kryžanowski, Andrej; Brilly, Mitja; Schnabl, Simon

    2013-04-01

    A dam failure is one of the most important problems in dam industry. Since the mechanical behavior of dams is usually a complex phenomenon existing classical mathematical models are generally insufficient to adequately predict the dam failure and thus the safety of dams. Therefore, numerical reliability methods are often used to model such a complex mechanical phenomena. Thus, the main purpose of the present paper is to present the response surface method as a powerful mathematical tool used to study and foresee the dam safety considering a set of collected monitoring data. The derived mathematical model is applied to a case study, the Moste dam, which is the highest concrete gravity dam in Slovenia. Based on the derived model, the ambient/state variables are correlated with the dam deformation in order to gain a forecasting tool able to define the critical thresholds for dam management.

  12. 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.

  13. Classification of the height and flexibility of the medial longitudinal arch of the foot

    OpenAIRE

    2012-01-01

    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 ...

  14. 76 FR 34799 - Permanent Dam Safety Modification at Cherokee, Fort Loudoun, Tellico, and Watts Bar Dams, TN

    Science.gov (United States)

    2011-06-14

    ... Permanent Dam Safety Modification at Cherokee, Fort Loudoun, Tellico, and Watts Bar Dams, TN AGENCY... various alternatives for permanent modifications to the existing dam facilities at Cherokee, Fort Loudoun, Tellico, and Watts Bar dams in Tennessee. The level of review will be determined after the public...

  15. Numerical Study of Two-Dimensional Viscous Flow over Dams

    Institute of Scientific and Technical Information of China (English)

    王利兵; 刘宇陆; 涂敏杰

    2003-01-01

    In this paper, the characteristics of two-dimensional viscous flow over two dams were numerically investigated. The results show that the behavior of the vortices is closely related to the space between two dams, water depth, Fr number and Reynolds number. In addition, the flow properties behind each dam are different, and the changes over two dams are more complex than over one dam. Finally, the relevant turbulent characteristics were analyzed.

  16. Research on Dam Simulation System Based on OpenGL

    Science.gov (United States)

    Li, Kairong; Wang, Juanni; Zuo, Kui; Yun, Jian

    Dam, not only has great ability to alleviate water shortages especially during the dry season which improve hydropower capacity, but also plays an imporant rule in the river ecosystem. Dam has significant effect in improving our water environment and protecting ecological system.This paper copes with the three-dimensional model of dams and discusses OpenGL modeling, lighting, material, model transformation, perspective transformation technologies to achieve visualization of the dam, and eventually we visualize the dam through concrete examples.

  17. Determination of Seepage and Analysis of Earth Dams (Case Study: Karkheh Dam

    Directory of Open Access Journals (Sweden)

    A. Kamanbedast

    2011-01-01

    Full Text Available Because of the increasing trend of building dam throughout Iran; it is necessary to optimize dam buildings and operations. Dam or Hydropower industry has two types of buildings; normally: (1 Concrete dams (2 Embankment (earth dams. Generally, scientists and engineers use different methods to enhance safety and decrease any errors in calculation due to maintenance of water storage especially hydro structure of the dam. It is necessary to investigate the dam seepage control; commonly used by several methods. Seepage is one of the important issues for design, build and maintenance of dams awareness. Seepage problem and its rules helps scientist to select a suitable method of monitoring and solving such problem. These methods of analysis were carried out at civil and construction project. In this study, one of latest method of investigation of seepage behavior were analytically evaluated and compared with the actual rules. Based on determine results; several suggestions and optimization method were suggested. Therefore, an optimum method was scientifically selected. Besides that, flow condition of porous environment with application of numeric program was analyzed. Finally, all the results were lunched out from seep/w soft which is the most significant program about this matter; use of finite elements method is specified for saturated and unsaturated environment. Thus; leakage and seepage were defined as function of (time and position. Subsequently, the best seepage solutions for the dam constructing were scientifically identified.

  18. 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).

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

    OpenAIRE

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

    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 ...

  20. Out-of-plane free vibration analysis of a cable-arch structure

    Science.gov (United States)

    Kang, H. J.; Zhao, Y. Y.; Zhu, H. P.

    2013-02-01

    Cable-arch structure has been widely used in many long-span structures such as cable roofs and cable-stayed arch bridges, but its dynamics is still not well understood. In this paper, the out-of-plane dynamic behavior of a cable-arch structure is investigated. The equations governing the out-of-plane free vibration of the structure are derived using d'Alembert's principle. A transfer matrix method is used to solve the governing equations and determine the frequencies of the out-of-plane vibration. The theories are then used to study two specific cases: free vibration of a model cable-arch and simulation of an arch erection process. The effects of some key parameters of cable and arch, such as tension of cable and radius, open-angle and shape of arch, are examined. The results indicate that in-plane and spatial cables can largely improve the out-of-plane dynamic behavior of arch structures, which are further verified by analyzing the out-of-plane buckling of cable-arch structures. The present work should be valuable and significant not only for the fundamental research but also engineering design of roofs and bridges.

  1. Contrast-enhanced magnetic resonance angiography of persistent fifth aortic arch in children

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Yumin; Zhu, Ming; Sun, Aimin; Li, Yuhua [Shanghai Jiao Tong University School of Medicine, Department of Radiology, Shanghai Children' s Medical Center, Shanghai (China); Jaffe, Richard B. [Primary Children' s Medical Center, Department of Medical Imaging, Salt Lake City, UT (United States); Gao, Wei [Shanghai Jiao Tong University School of Medicine, Department of Cardiology, Shanghai Children' s Medical Center, Shanghai (China)

    2007-03-15

    Cine angiography and echocardiography have been utilized to diagnose congenital aortic arch anomalies. However, the visualization of great vessels by echocardiography is limited, while cine angiography requires cardiac catheterization with ionizing radiation. Contrast-enhanced magnetic resonance angiography (MRA) is a noninvasive modality suitable for visualization of congenital aortic arch anomalies. To evaluate the utility of contrast-enhanced MRA in the diagnosis of persistent fifth aortic arch, a rare congenital aortic arch anomaly, and to compare the diagnostic accuracy of MRA with that of echocardiography and cine angiography. In four pediatric patients, contrast-enhanced MRA studies were performed for diagnosing persistent fifth aortic arch. The findings of MRA were compared with echocardiographic findings and confirmed by cine angiography and operation. Transthoracic surface echocardiography noted an aberrant vessel arising from the ascending aorta in two of four patients; the etiology of this vessel was uncertain. In the other two patients a diagnosis of coarctation was made. Of the four patients, only one was diagnosed with interruption of the aortic arch. Contrast-enhanced MRA clarified uncertain echocardiographic findings, enabling the correct diagnosis of persistent fifth aortic arch with fourth aortic arch interruption in all four patients. Contrast-enhanced MRA is a safe, accurate, and fast imaging technique for the evaluation of persistent fifth aortic arch and may obviate the need for conventional cine angiography. Cardiac catheterization may be reserved for some types of complicated congenital heart disease and for obtaining hemodynamic information. (orig.)

  2. [Diagnosis and follow-up of reduction of fractures of the zygomatic arch].

    Science.gov (United States)

    Friedrich, R E; Volkenstein, R J

    1994-08-01

    Ultrasound and standard x-ray investigations before and after the reduction of the fractures were performed in 17 patients with zygomatic arch fractures. The ultrasound investigation of the bone surface is recommended as an additional diagnostic tool in the diagnosis and control of the reduction of zygomatic arch fractures. Intraoperative ultrasound imaging under sterile conditions is easy to apply and enables the surgeon to optimise therapeutic results. In 5 cases based on an intraoperative sonogram further reductions of zygomatic arch fractures were carried out. In another referred patient the diagnosis of a zygomatic arch fracture was excluded by ultrasound and confirmed by standard x-ray examinations.

  3. A rare cause of cervical spinal stenosis: posterior arch hypoplasia in a bipartite atlas

    Energy Technology Data Exchange (ETDEWEB)

    Atasoy, C. [Emek, Kirim Caddesi, Ankara (Turkey); Department of Radiology, Ankara University School of Medicine (Turkey); Fitoz, S.; Karan, B.; Erden, I.; Akyar, S. [Department of Radiology, Ankara University School of Medicine (Turkey)

    2002-03-01

    We describe CT and MRI of a previously unreported combination of atlantoaxial anomalies consisting of posterior arch hypoplasia in a bipartite atlas with an os odontoideum, in a 30-year-old woman presenting with neck and left arm pain. MRI showed the os odontoideum, marked stenosis of the spinal canal at the level of the atlas, with cord compression and evidence of myelopathy. CT revealed a bipartite atlas with midline clefts in anterior and posterior arches, thickening in the anterior arch and hypoplasia of the posterior arch with incurving of both hemiarches. Flexion and extension radiographs demonstrated atlantoaxial instability. (orig.)

  4. Elastic responses of underground circular arches considering dynamic soil-structure interaction: A theoretical analysis

    Institute of Scientific and Technical Information of China (English)

    Hai-Long Chen; Feng-Nian Jin; Hua-Lin Fan

    2013-01-01

    Due to the wide applications of arches in underground protective structures,dynamic analysis of circular arches including soil-structure interactions is important.In this paper,an exact solution of the forced vibration of circular arches subjected to subsurface denotation forces is obtained.The dynamic soil-structure interaction is considered with the introduction of an interfacial damping between the structure element and the surrounding soil into the equation of motion.By neglecting the influences of shear,rotary inertia and tangential forces and assuming the arch incompressible,the equations of motion of the buried arches were set up.Analytical solutions of the dynamic responses of the protective arches were deduced by means of modal superposition.Arches with different opening angles,acoustic impedances and rise-span ratios were analyzed to discuss their influences on an arch.The theoretical analysis suggests blast loads for elastic designs and predicts the potential failure modes for buried protective arches.

  5. Chemical - Elwha River Dam Removal Study

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This study examines the ecosystem response of the Elwha River to the removal of the Elwha River dams. We will measure the following attributes of ecosystem response:...

  6. Biological - Elwha River Dam Removal Study

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This study examines the ecosystem response of the Elwha River to the removal of the Elwha River dams. We will measure the following attributes of ecosystem response:...

  7. Dams life; La vie des barrages

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    This paper summarizes the conclusions of the annual inspections of French dams in operation (fissures, water oozing, concrete swelling etc..). Only the observations which require a special attention are reported. (J.S.)

  8. Physical - Elwha River Dam Removal Study

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This study examines the ecosystem response of the Elwha River to the removal of the Elwha River dams. We will measure the following attributes of ecosystem response:...

  9. White Sturgeon Passage at The Dalles Dam

    Science.gov (United States)

    ,

    2008-01-01

    Researchers at the USGS Western Fisheries Research Center's Columbia River Research Laboratory, working with the U.S. Army Corps of Engineers, sought to better understand upstream and downstream passage of white sturgeon at dams. A study at The Dalles Dam provided the opportunity to compare two fish ladders; one that passes sturgeon upstream to one that does not, to determine if subtle differences in construction result in better passage of white sturgeon. Researchers conducted a study using a combination of acoustic and radio telemetry technologies to obtain information on juvenile and adult white sturgeon near The Dalles Dam, with the objectives of characterizing the distribution and movements of white sturgeon in the immediate vicinity of the dam and to determine timing and routes of upstream and downstream passage.

  10. Final Design Analysis : Lake Ladora Dam Repair

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report is intended to present Rocky Mountain Arsenal with details concerning the remedial repair for Ladora Dam to meet the geotechnical concerns and hydrologic...

  11. Effects of different medial arch support heights on rearfoot kinematics

    Science.gov (United States)

    Mayer, Frank; Baur, Heiner

    2017-01-01

    Background Foot orthoses are usually assumed to be effective by optimizing mechanically dynamic rearfoot configuration. However, the effect from a foot orthosis on kinematics that has been demonstrated scientifically has only been marginal. The aim of this study was to examine the effect of different heights in medial arch-supported foot orthoses on rear foot motion during gait. Methods Nineteen asymptomatic runners (36±11years, 180±5cm, 79±10kg; 41±22km/week) participated in the study. Trials were recorded at 3.1 mph (5 km/h) on a treadmill. Athletes walked barefoot and with 4 different not customized medial arch-supported foot orthoses of various arch heights (N:0 mm, M:30 mm, H:35 mm, E:40mm). Six infrared cameras and the `Oxford Foot Model´ were used to capture motion. The average stride in each condition was calculated from 50 gait cycles per condition. Eversion excursion and internal tibia rotation were analyzed. Descriptive statistics included calculating the mean ± SD and 95% CIs. Group differences by condition were analyzed by one factor (foot orthoses) repeated measures ANOVA (α = 0.05). Results Eversion excursion revealed the lowest values for N and highest for H (B:4.6°±2.2°; 95% CI [3.1;6.2]/N:4.0°±1.7°; [2.9;5.2]/M:5.2°±2.6°; [3.6;6.8]/H:6.2°±3.3°; [4.0;8.5]/E:5.1°±3.5°; [2.8;7.5]) (p>0.05). Range of internal tibia rotation was lowest with orthosis H and highest with E (B:13.3°±3.2°; 95% CI [11.0;15.6]/N:14.5°±7.2°; [9.2;19.6]/M:13.8°±5.0°; [10.8;16.8]/H:12.3°±4.3°; [9.0;15.6]/E:14.9°±5.0°; [11.5;18.3]) (p>0.05). Differences between conditions were small and the intrasubject variation high. Conclusion Our results indicate that different arch support heights have no systematic effect on eversion excursion or the range of internal tibia rotation and therefore might not exert a crucial influence on rear foot alignment during gait. PMID:28257426

  12. Full-Arch Rehabilitation of a Patient With Cyclic Neutropenia.

    Science.gov (United States)

    Block, Michael S; Brindis, Marco; Block, Celeste A; Berron, Joaquin M

    2015-09-01

    The purpose of this report is to discuss the treatment of a patient with cyclic neutropenia. This patient presented with flared teeth, thin alveolar bone, and mobile teeth. A staged approach was used to remove her teeth, augment the bone, use immediate fixed provisional to determine the type of final prostheses, and ultimately to use cone-shaped overdenture attachments to retain her final prostheses. The result was rehabilitation of the patient with esthetic full-arch fixed-removable dentures with no adverse sequelae in this patient with this systemic disease.

  13. A comparative study of inter-abutment distance of dies made from full arch dual-arch impression trays with those made from full arch stock trays: An in vitro study

    OpenAIRE

    Reddy Jagan; Prashanti E; Kumar G; Suresh Sajjan M; Mathew Xavier

    2009-01-01

    Objectives: The dual-arch impression technique is convenient in that it makes the required maxillary and mandibular impressions, as well as the inter-occlusal record in one procedure. The accuracy of inter-abutment distance in dies fabricated from dual-arch impression technique remains in question because there is little information available in the literature. Materials and Methods: This study was conducted to evaluate the accuracy of inter-abutment distance in dies obtained from full ar...

  14. Reliability Analysis of High Rockfill Dam Stability

    Directory of Open Access Journals (Sweden)

    Ping Yi

    2015-01-01

    Full Text Available A program 3DSTAB combining slope stability analysis and reliability analysis is developed and validated. In this program, the limit equilibrium method is utilized to calculate safety factors of critical slip surfaces. The first-order reliability method is used to compute reliability indexes corresponding to critical probabilistic surfaces. When derivatives of the performance function are calculated by finite difference method, the previous iteration’s critical slip surface is saved and used. This sequential approximation strategy notably improves efficiency. Using this program, the stability reliability analyses of concrete faced rockfill dams and earth core rockfill dams with different heights and different slope ratios are performed. The results show that both safety factors and reliability indexes decrease as the dam’s slope increases at a constant height and as the dam’s height increases at a constant slope. They decrease dramatically as the dam height increases from 100 m to 200 m while they decrease slowly once the dam height exceeds 250 m, which deserves attention. Additionally, both safety factors and reliability indexes of the upstream slope of earth core rockfill dams are higher than that of the downstream slope. Thus, the downstream slope stability is the key failure mode for earth core rockfill dams.

  15. OVERVIEW OF DAM GULLY EROSION RESEARCH

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Traditionally gully erosion has been identified with the dissection of the landscape in agricultural settings but it is also recognized as a prevalent erosion feature in earthen dam auxiliary spillways and embankments. Flows through earthen spillways and over dam embankments, due to large rainfall events, have the potential to erode and breach the dam or spillway and result in catastrophic releases from the reservoir. The gully erosion process in an earthen spillway or on an embankment can be characterized by stages of initiation, development, and migration of a headcut. A headcut is defined as a near vertical drop at the upstream end of a gully. The rate of headcut migration is important in determining the breach potential of an earthen spillway and dam embankment. A research program is being conducted to examine the gully erosion processes of earthen dam auxiliary spillways and embankments. This paper describes: 1) the unique test facilities constructed to examine the dominant factors affecting the erosion of earthen spillways and embankments; 2) the observations of the erosion processes and results to date; and 3) the predictive relationships that have been developed for dam gully erosion research at the ARS Hydraulic Engineering Research Unit laboratory in Stillwater, OK.

  16. Distributional Impacts of Large Dams in China

    Science.gov (United States)

    Bao, X.

    2010-12-01

    Dams on a river are believed to have heterogeneous impacts to the upstream, local and downstream areas. Generally, irrigation dams will bring benefits to the downstream by facilitating more irrigation, while it will bring negative impacts to upstream due to inundation or no impact to local area as a combination result of population dislocation and economic benefits. This paper checked the impacts of large dams (above 100 meters) on the upstream, downstream and local area, using 2000-2008 county level data in China. Robust heterogeneous impacts of different categories of dams (mainly dams serving for irrigation, hydropower, or other purposes) were found on different areas, using IV regression approaches. Dams higher than 100 meters are significantly and heterogeneously impacting agricultural production, urban employment and rural per capita income. Its beneficial impact on agriculture production is significant for downstream especially in continuous drought years. But its impacts on social welfare indicators, such as primary school enrollment and hospital beds, are not heterogeneously different across regions.

  17. Walter Bouldin Dam failure and reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-09-01

    Walter Bouldin is one of several hydroelectric developments of Alabama Power Company. On February 10, 1975, an earth embankment section of Walter Bouldin Dam was breached, causing total evacuation of the forebay reservoir and rendering the 225-MW power plant inoperable. The Federal Power Commission instituted an investigation of the dam failure, and a report on the investigation was published in February 1976. Subsequently, an evidentiary hearing was held before an administrative law judge who issued his initial decision on August 19, 1976. The Commission, on April 21, 1977, issued its Opinion No. 795 in which it adopted the initial decision with modifications and terminated the investigation of failure of Walter Bouldin Dam. Opinion No. 795 directs the staff of the Bureau of Power to prepare, for the future guidance of the Commission, a report on the deficiencies which were found in its investigation, together with advice as to how such deficiencies have been and should be remedied. Also, it directs the staff of the Bureau of Power to address certain general recommendations included in the initial decision. This report was prepared in response to that directive and summaries information on the dam failure and its investigation; the evidentiary hearing; the judge's recommendations, the reconstruction of the Bouldin Dam; and the evalution and status of the Federal Energy Regulatory Commission Dam safety program. (LCL)

  18. Theory on real-time control of construction quality and progress and its application to high arc dam

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A complete scheme for solving the key scientific problems associated with high-standard,high-intensity continuous construction of high arch dams was presented. First,based on a coupling analysis of construction system decomposition and coordination for a high arc dam,a mathematical model for real-time control of construction quality and progress that considers complex constraints was developed. Second,a method of progress control was proposed based on a dynamic simulation. Third,a dynamic quality control mechanism was established based on construction information collected using a PDA. Fourth,a system for integrating collected information,progress simulation and quality control analyses under a network environment was developed. Finally,these methods were applied to a practical project to show that each aspect of a construction process can be managed effectively and that real-time monitoring and feedback control can be realized. Our methods provide new theoretical principles and technical measures for quality and progress control in the high arc dam construction process.

  19. Use and application of inflatable dam seals in large concrete dams

    Energy Technology Data Exchange (ETDEWEB)

    Dickes, G. [Structural Preservation Systems Inc., Hanover, MD (United States)

    2001-10-01

    The successful installation of inflatable dam seals has been accomplished at several large concrete dams in the United States. This accomplishment was recently realized for the first time in Canada. The minimization of water intrusion caused by failed water stops in monolithic dams by a small diameter inflatable seal is one of the many uses for the device. Many problems encountered at large concrete dams are related to stress control of alkali-aggregate or alkali silica reaction (AAR, ASR), and the inflatable dam seal fits in as part of this control system. Many of the problems with concrete dams are due to AAR which causes concrete to expand, resulting in cracking of concrete and misalignment of equipment as two of the most important issues. A transverse vertical saw cut through the upper section of the concrete structure was one of the methods used to alleviate the stresses brought about by AAR. This method has been used on a number of occasions in both Canada and the United States. Once the saw cut is complete, from the upstream face to the downstream face, controlling the water flow in the kerf (13-19 millimeter) presents a major challenge. Successfully sealing failed water stops and saw cuts was accomplished by installing inflatable dam seals with vertical heights in excess of 38 meters. A specific seal must be designed in each case. Several elements of the composite construction seal meet the engineering requirements set forth by Dam Safety Officials and Engineers and Owners. Some case histories were presented, namely the Harry S. Truman Dam in Missouri, the Tennessee Valley Authority at several sites, the Hiwassee Dam in North Carolina, the Fontana Dam in Tennessee, and the Mactaquac Generating Station in New Brunswick. 10 refs., 11 figs.

  20. 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.

  1. 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.

  2. A radiological study on lumbar spondylolisthesis with intact neural arch

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Myung Ju; Suh, Young Jun; Joe, Seong Jeh; Yoon, Jong Sup [Han-Gang Sung-Shim Hospital, Seoul (Korea, Republic of)

    1980-12-15

    The purpose of this paper is to evaluate and analyze the radiological findings of 13 cases of lumbar spondylolisthesis with intact neural arch at Han-Gang Sung- Shim Hospital during period from Jan. 1975 to June 1980. 1. The age distribution of the patients varied from 31 to 83 years old. The average of the age was 53 years old. 12 patients were female and only one patient was male. 2. All cases revealed anterior slipping of the L4 body on the L5 body, of which degree was classified by Meyerding's method, first degree in 12 patients and second degree in one patient. 3. The angle between the pedicle and inferior articular facet of affected vertebra was measured by Junghann's method. The average of angle was 123 degree. 4. Of 13 cases, 2 cases who had neural compression caused by dislocation of the vertebral bodies and intrusion of lamina and arthritic facets into stenotic spinal canal treated by laminar decompression including foraminotomy. Good results were obtained. 5. The secondary degenerative change of the vertebra was considered to be the cause of the spondylolisthesis with intact neural arch.

  3. 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.

  4. 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.

  5. 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.

  6. High- compared to low-arched athletes exhibit smaller knee abduction moments in walking and running.

    Science.gov (United States)

    Powell, Douglas W; Andrews, Samantha; Stickley, Cris; Williams, D S Blaise

    2016-12-01

    High- (HA) and low-arched athletes (LA) experience distinct injury patterns. These injuries are the result of the interaction of structure and biomechanics. A suggested mechanism of patellofemoral pain pertains to frontal plane knee moments which may be exaggerated in LA athletes. We hypothesize that LA athletes will exhibit greater peak knee abduction moments than high-arched athletes.

  7. "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.

  8. 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.

  9. 49 CFR 230.61 - Arch tubes, water bar tubes, circulators and thermic siphons.

    Science.gov (United States)

    2010-10-01

    ... (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND 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...

  10. [The value of ultrasonography in the diagnosis of zygomatic arch fractures].

    Science.gov (United States)

    Friedrich, R E; Volkenstein, R J

    1991-01-01

    In 15 cases ultrasonograms were used to verify the result of a zygomatic fracture reduction and were correlated to conventional x-ray films. Both the pre- and postoperative ultrasonograms demonstrated all fractures of the zygomatic arch. Ultrasonographic imaging of the non-exposed bone surfaces enables the operator to monitor the reduction of zygomatic arch fractures intraoperatively, and thus optimize the treatment results.

  11. 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....

  12. Relation of Gothic arch apex to dentist-assisted centric relation.

    Science.gov (United States)

    Myers, M; Dziejma, R; Goldberg, J; Ross, R; Sharry, J

    1980-07-01

    These data suggest that the widely held belief that thumb pressure can position the mandible consistently more posterior than the position indicated by the Gothic arch apex is unfounded. Furthermore, this study provides no evidence to support the contention that the dentist-assisted jaw relation is more reproducible than the relation indicated by the Gothic arch apex.

  13. Selective cerebro-myocardial perfusion in complex congenital aortic arch pathology: a novel technique.

    Science.gov (United States)

    De Rita, Fabrizio; Lucchese, Gianluca; Barozzi, Luca; Menon, Tiziano; Faggian, Giuseppe; Mazzucco, Alessandro; Luciani, Giovanni Battista

    2011-11-01

    Simultaneous cerebro-myocardial perfusion has been described in neonatal and infant arch surgery, suggesting a reduction in cardiac morbidity. Here reported is a novel technique for selective cerebral perfusion combined with controlled and independent myocardial perfusion during surgery for complex or recurrent aortic arch lesions. From April 2008 to April 2011, 10 patients with arch pathology underwent surgery (two hypoplastic left heart syndrome [HLHS], four recurrent arch obstruction, two aortic arch hypoplasia + ventricular septal defect [VSD], one single ventricle + transposition of the great arteries + arch hypoplasia, one interrupted aortic arch type B + VSD). Median age was 63 days (6 days-36 years) and median weight 4.0 kg (1.6-52). Via midline sternotomy, an arterial cannula (6 or 8 Fr for infants) was directly inserted into the innominate artery or through a polytetrafluoroethylene (PTFE) graft (for neonates cerebro-myocardial perfusion was 39 ± 18 min (17-69). Weaning from cardiopulmonary bypass was achieved without inotropic support in three and with low dose in seven patients. One patient required veno-arterial extracorporeal membrane oxygenation. Four patients, body weight cerebro-myocardial perfusion is feasible in patients with complex or recurrent aortic arch disease, starting from premature newborn less than 2.0 kg of body weight to adults. The technique is as safe as previously reported methods of cerebro-myocardial perfusion and possibly more versatile.

  14. Design and construction of Nemiscau-1 Dam, the first asphalt core rockfill dam in North America

    Energy Technology Data Exchange (ETDEWEB)

    Alicescu, V.; Tournier, J.P. [Hydro-Quebec, Montreal, PQ (Canada); Vannobel, P. [Societe d' Energie de la Baie James, Montreal, PQ (Canada)

    2008-07-01

    The concept of asphalt as a waterproofing medium inside embankment dams was originally developed in Germany in the 1960s. More than 100 asphalt core rockfill (ACRD) dams have been completed or are under construction. They all have a strong record without any seepage problems or required maintenance. After using the glacial till as waterproofing material for its embankment dams for more than 50 years, Hydro-Quebec is now looking to develop new dam concepts, mainly for the zones where natural waterproofing materials do not exist. In order to do so, the company has decided to design and construct the Nemiscau-1 Dam as a prototype ACRD. This paper presented the detailed design criteria, technical specifications as well as some information concerning the construction of the dam such as asphalt mix design. The given dam site, geology and materials is well suited for a dam with an asphalt core and the chosen core thickness of minimum 400 mm was found to be appropriate, given the small net water head. The main reservoir levels as well as the characteristics of the dam were also listed. Information on the general construction of the dam was provided. It was concluded that the longitudinal profile of the rock excavation and concrete plinth must be optimized, with an optimum balance between the rock excavation, the volume and shape of the concrete plinth and finally, the placement of the asphalt core with the manual method. Several combinations of these 3 elements must be analyzed at the design stage and the most cost effective one should be applied on site. 5 tabs., 7 figs.

  15. 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.

  16. 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.

  17. 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.

  18. EFFECT OF HOTZ PLATE APPLIANE TO MAXILLARY ARCH DEVELOPMENT PATIENTS WITH CLEFT LIP AND PALATE

    Directory of Open Access Journals (Sweden)

    Edy Machmud

    2015-06-01

    Full Text Available The purpose of this study was to analyze the effect of hotz plate appliance to maxillary arch development of complete unilateral cleft lip and palate patient. The subjects were divided into two groups. The first group consisted of 6 patients, aged under two years with hotz appliance, recruited from Hasan Sadikin Hospital Bandung, and the second group, as control group, consisted of 6 patients, aged under two years, without hotz appliance, recruited from Haji Hosiptal Makassar. It was showed that in group with hotz plate appliance, no difference found on the size of anterior maxillary arch and minor maxillary arch. On the other hand, in the control group, minor maxillary arch was longer than major maxillary arch. It was concluded that hotz plate appliances affected that palatal development of patient with complete unilateral cleft lip and palate.

  19. 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.

  20. EXPERIMENTAL INVESTIGATION OF THE FAILURE OF CASCADE LANDSLIDE DAMS

    Institute of Scientific and Technical Information of China (English)

    NIU Zhi-pan; XU Wei-lin; LI Nai-wen; XUE Yang; CHEN Hua-yong

    2012-01-01

    This paper preseuts results of model tests for the landslide dam failure of a single dam and cascade dams in a sloping channel.The dams were designed to be regular trapezoid with fine sand.A new measuring method named the labeled line locating method was used to digitalize the captured instantaneous pictures.Under two differem inflow discharges,the morphological evolution and the flow patterns during one dam failure and the failure of cascade dams were investigated.The results indicate that when the inflow discharge is large,the deformation pattern of the downstream dam is similar to that of the upstream dam,and both dams are characterized with the overtopping scour throughout the dam failure process.When the inflow discharge is small,the upstream dam is scoured mainly through a sluice slot formed by the longitudinal incision,and the downstream dam is characterized with the overtopping scour.The data set presented in this paper can be used for the validation of numerical models and provide a reference for the flood risk management of cascade landslide dams.

  1. Toward policies and decision-making for dam removal.

    Science.gov (United States)

    Doyle, Martin W; Harbor, Jon M; Stanley, Emily H

    2003-04-01

    Dam removal has emerged as a critical issue in environmental management. Agencies responsible for dams face a drastic increase in the number of potential dam removals in the near future. Given limited resources, these agencies need to develop ways to decide which dams should be removed and in what order. The underlying science of dam removal is relatively undeveloped and most agencies faced with dam removal lack a coherent purpose for removing dams. These shortcomings can be overcome by the implementation of two policies by agencies faced with dam removal: (1) the development and adoption of a prioritization scheme for what constitutes an important dam removal, and (2) the establishment of minimum levels of analysis prior to decision-making about a dam removal. Federal and state agencies and the scientific community must encourage an initial experimental phase of dam removal during which only a few dams are removed, and these are studied intensively. This will allow for the development of the fundamental scientific understanding needed to support effective decision-making in the future and minimize the risk of disasters arising from poorly thought out dam removal decisions.

  2. File list: NoD.Emb.05.AllAg.Maxillary_arch_junction [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  9. File list: NoD.Emb.20.AllAg.Maxillary_arch_junction [Chip-atlas[Archive

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  10. 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.

  11. 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...

  12. 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.

  13. Constructing Active Architectures in the ArchWare ADL

    CERN Document Server

    Morrison, Ron; Balasubramaniam, Dharini; Mickan, Kath; Oquendo, Flavio; Cîmpan, Sorana; Warboys, Brian; Snowdon, Bob; Greenwood, Mark

    2010-01-01

    Software that cannot change is condemned to atrophy: it cannot accommodate the constant revision and re-negotiation of its business goals nor intercept the potential of new technology. To accommodate change in such systems we have defined an active software architecture to be: dynamic in that the structure and cardinality of the components and interactions are not statically known; updatable in that components can be replaced dynamically; and evolvable in that it permits its executing specification to be changed. Here we describe the facilities of the ArchWare architecture description language (ADL) for specifying active architectures. The contribution of the work is the unique combination of concepts including: a {\\pi}-calculus based communication and expression language for specifying executable architectures; hyper-code as an underlying representation of system execution; a decomposition operator to break up and introspect on executing systems; and structural reflection for creating new components and bind...

  14. Modelos ARCH, GARCH y EGARCH: aplicaciones a series financieras

    Directory of Open Access Journals (Sweden)

    Cepeda Cuervo Edilberto

    2008-08-01

    Full Text Available En este artículo se incluye una descripción de los modelos
    ARCH, GARCH y EGARCH, y de los procesos de estimación de sus
    parámetros usando máxima verosimilitud. Se propone un modelo
    alternativo para el análisis de series financieras y se estudian
    las series de precios y de retornos de las acciones de
    Gillette. La selección de modelos usando los criterios AIC y
    BIC permite concluir que, de los modelos considerados el
    GARCH(1,2 es el que mejor explica el comportamiento de los
    precios de las acciones y el EGARCH(2,1 es el que mejor
    explica la serie de los retornos.

  15. Explaining operational modal analysis with data from an arch bridge

    Science.gov (United States)

    Magalhães, Filipe; Cunha, Álvaro

    2011-07-01

    This tutorial paper aims to introduce the topic of operational modal analysis to non-specialists on the subject. First of all, it is stressed the relevance of this experimental technique particularly in the assessment of important civil infrastructure. Then, after a synthesis of required theoretical background, three of the most powerful algorithms for output-only modal identification are presented. The several steps of these identification procedures are illustrated with the processing of data collected on a concrete arch bridge with a span of 280 m. As the use of operational modal analysis in the context of structural health monitoring is a subject under active research, this theme is also introduced and briefly exemplified with data continuously recorded at the same bridge.

  16. International small dam safety assurance policy benchmarks to avoid dam failure flood disasters in developing countries

    Science.gov (United States)

    Pisaniello, John D.; Dam, Tuyet Thi; Tingey-Holyoak, Joanne L.

    2015-12-01

    In developing countries small dam failure disasters are common yet research on their dam safety management is lacking. This paper reviews available small dam safety assurance policy benchmarks from international literature, synthesises them for applicability in developing countries, and provides example application through a case study of Vietnam. Generic models from 'minimum' to 'best' practice (Pisaniello, 1997) are synthesised with the World Bank's 'essential' and 'desirable' elements (Bradlow et al., 2002) leading to novel policy analysis and design criteria for developing countries. The case study involved 22 on-site dam surveys finding micro level physical and management inadequacies that indicates macro dam safety management policy performs far below the minimum benchmark in Vietnam. Moving assurance policy towards 'best practice' is necessary to improve the safety of Vietnam's considerable number of hazardous dams to acceptable community standards, but firstly achieving 'minimum practice' per the developed guidance is essential. The policy analysis/design process provides an exemplar for other developing countries to follow for avoiding dam failure flood disasters.

  17. Channel changes downstream from a dam

    Science.gov (United States)

    Hadley, R.F.; Emmett, W.W.

    1998-01-01

    A flood-control dam was completed during 1979 on Bear Creek, a small tributary stream to the South Platte River in the Denver, Colorado, area. Before and after dam closure, repetitive surveys between 1977 and 1992 at five cross sections downstream of the dam documented changes in channel morphology. During this 15-year period, channel width increased slightly, but channel depth increased by more than 40 percent. Within the study reach, stream gradient decreased and median bed material sizes coarsened from sand in the pools and fine gravel on the riffle to a median coarse gravel throughout the reach. The most striking visual change was from a sparse growth of streamside grasses to a dense growth of riparian woody vegetation.

  18. Design of tailing dam using red mud

    Science.gov (United States)

    Rout, Subrat; Sahoo, Tapaswini; Das, Sarat

    2013-06-01

    Red mud, waste industrial product from aluminum industries produced approximately 75 million tonnes every year with less than half of this is used. Storage of this unutilized red mud takes vast tracts of usable land and pollutes, land, air and water. Construction of high embankments, under passes, flyovers, tailing dams uses vast tract of natural resources (top soil) is also matter of concern as its takes thousands of years to form the natural soil. This paper discusses use of red mud for construction of tailing dam based on laboratory findings and finite element analysis. The geotechnical properties such as plasticity, compaction, permeability, shear strength characteristics and dispersion of red mud are presented. Stability and seepage analysis of tailing dams as per finite element analysis using the above geotechnical parameters is presented.

  19. Development and Challenges of Super High Dams in China and Other Countries%我国超级高坝的发展与挑战

    Institute of Scientific and Technical Information of China (English)

    王爱玲; 邓正刚

    2015-01-01

    The statistics on high dams with a height more than 200 m in abroad and home under operation, construction or planning shows that the super high dam construct earlier and continues to develop in foreign countries, and starts later in but rapid in China. The super high dams mainly belong to concrete arch dam, concrete gravity dam, clay core wall rockfill dam or concrete face rockfill dam, and all super high dams which have been put into operation can safely and reliably operate. The development and characteristics of hydropower engineering in China are analyzed and the result shows the development of super high dams in China will face the challenges of high safety requirement, lack of relevant technical standards, joint research requirements on key technologies, risk prevention and control and effective management in whole operation life.%对国内外已建、在建和拟建200 m以上超级高坝进行统计表明,国外超级高坝建设起步较早,发展持续不断,我国起步较晚,但发展较快;超级高坝主要集中在混凝土拱坝、混凝土重力坝、土心墙堆石坝和混凝土面板堆石坝等4种坝型,已建工程都能安全可靠运行。通过分析我国水电工程发展趋势以及工程特点,我国超级高坝的发展面临安全要求高、相关技术标准缺乏、关键技术需联合攻关、风险防控和全寿命周期的有效管理等方面的挑战。

  20. Jaw muscle pain and its effect on gothic arch tracings.

    Science.gov (United States)

    Obrez, A; Stohler, C S

    1996-04-01

    Perceived changes in occlusion and decreased range of motion are often expressed by patients with masticatory muscle pain. The adverse loading of craniomandibular tissues that results from an inadequate maxillomandibular relationship in combination with the coexisting dysfunction is widely regarded as the cause of pain. This study was designed to test whether pain can cause significant changes in position of the mandible and therefore form the basis for any perceived changes in the maxillomandibular relationship. A second objective was to determine whether pain can cause changes in the mandibular range of motion. Five subjects who rated pain intensity on a visual analog scale were used in a single-blind, randomized, repeated-measures study design. Tonic muscle pain was induced by infusion of 5% hypertonic saline solution into the central portion of the superficial masseter muscle. Isotonic saline solution was used as a control, with subjects blinded to the type of substance given. The effect of pain on the position of the apex of the gothic arch tracing, the direction of the lateral mandibular border movements, and the mandibular range of motion was studied in a horizontal plane with minimal occlusal separation. Pain significantly affected the position of the apex of the gothic arch tracing in anterior (F = 11.46, p = 0.03) and transverse (F = 35.0, p = 0.004) directions. Similarly, pain affected the orientation of the mandibular lateral border movements (F = 12.44, p = 0.02) and their magnitude (F = 14.97, p = 0.01). All pain-induced effects proved to be reversible. The observed effect of pain can explain the perceived change of bite that is frequently noted by patients with orofacial pain. This study provided evidence of an alternative causal relationship between pain and changes in occlusal relationship and questions occlusal therapy as treatment, directed toward the elimination of the underlying cause in patients with masticatory muscle pain.

  1. Optimizing the dammed: water supply losses and fish habitat gains from dam removal in California.

    Science.gov (United States)

    Null, Sarah E; Medellín-Azuara, Josué; Escriva-Bou, Alvar; Lent, Michelle; Lund, Jay R

    2014-04-01

    Dams provide water supply, flood protection, and hydropower generation benefits, but also harm native species by altering the natural flow regime and degrading aquatic and riparian habitat. Restoring some rivers reaches to free-flowing conditions may restore substantial environmental benefits, but at some economic cost. This study uses a systems analysis approach to preliminarily evaluate removing rim dams in California's Central Valley to highlight promising habitat and unpromising economic use tradeoffs for water supply and hydropower. CALVIN, an economic-engineering optimization model, is used to evaluate water storage and scarcity from removing dams. A warm and dry climate model for a 30-year period centered at 2085, and a population growth scenario for year 2050 water demands represent future conditions. Tradeoffs between hydropower generation and water scarcity to urban, agricultural, and instream flow requirements were compared with additional river kilometers of habitat accessible to anadromous fish species following dam removal. Results show that existing infrastructure is most beneficial if operated as a system (ignoring many current institutional constraints). Removing all rim dams is not beneficial for California, but a subset of existing dams are potentially promising candidates for removal from an optimized water supply and free-flowing river perspective. Removing individual dams decreases statewide delivered water by 0-2282 million cubic meters and provides access to 0 to 3200 km of salmonid habitat upstream of dams. The method described here can help prioritize dam removal, although more detailed, project-specific studies also are needed. Similarly, improving environmental protection can come at substantially lower economic cost, when evaluated and operated as a system.

  2. Study on dynamic anti-sliding stability of a high gravity dam considering complex dam foundation

    Directory of Open Access Journals (Sweden)

    Deng-hong CHEN

    2011-06-01

    Full Text Available There existed some limitations when analyzing the anti-sliding seismic stability of dam-foundation system by traditional pseudo-static method and response spectrum method. The dynamic strength reduction method was used to study on the deep anti-sliding stability of a high gravity dam considering complex dam foundation under strong earthquake-induced ground action. The static analysis was firstly carried out by reducing the shear strength parameters of the dam foundation’s rock mass with equal proportion. Then, the time-history seismic analysis was carried out based on the static analysis. It was proposed as one of dynamic instability criterions that the peak values of the dynamic displacements and plastic strain energy change suddenly with increasing strength reduction coefficient. The elasto-plastic behavior of the dam foundation was idealized using Drucker–Prager yield criterion based on associated flow rule assumption. Through the static, dynamic strength reduction analysis and dynamic linear elastic analysis of the overflow dam monolith of a high gravity dam, the results’ reliability of elastic-plastic time history analysis was confirmed. The results also showed that the rock mass strength of the high gravity dam foundation has higher strength reserve coefficient. The instability criterions of dynamic strength reduction method proposed were feasible. Although the static anti-slide analysis methods and standards of gravity dam based on the numerical methods are being discussed at present, the dynamic calculation method and instability criterions proposed in this paper would provide some meaningful suggestions for the dynamic analysis of the similar projects.

  3. National Inventory of Dams Coastal California Extract 2010

    Data.gov (United States)

    California Department of Resources — The National Inventory of Dams (NID) is a congressionally authorized database, which documents dams in the U.S. and its territories. The NID was most recently...

  4. Research review of the cement sand and gravel (CSG) dam

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    The cement sand and gravel (CSG) dam is a new style of dam that owes the advantages both of the concrete faced rock-fill dam (CRFD) and roller compacted concrete (RCC) gravity dam,because of which it has attracted much attention of experts home and abroad.At present,some researches on physic-mechanical property of CSG material and work behavior of CSG dam have been done.This paper introduces the development and characteristics of CSG dam systematically,and summarizes the progress of the study on basic tests,constitutive relation of CSG material and numerical analysis of CSG dam,in addition,indicates research and application aspect of the dam.

  5. Inventory of Dams in the State of Iowa

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — Permitted dams in Iowa and associated attributes, as recorded by the Floodplain Section of the DNR. The dams regulated are those with the parameters listed below: a....

  6. Harvesting river water through small dams promote positive environmental impact.

    Science.gov (United States)

    Agoramoorthy, Govindasamy; Chaudhary, Sunita; Chinnasamy, Pennan; Hsu, Minna J

    2016-11-01

    While deliberations relating to negative consequences of large dams on the environment continue to dominate world attention, positive benefits provided by small dams, also known as check dams, go unobserved. Besides, little is known about the potential of check dams in mitigating global warming impacts due to less data availability. Small dams are usually commissioned to private contractors who do not have clear mandate from their employers to post their work online for public scrutiny. As a result, statistics on the design, cost, and materials used to build check dams are not available in public domain. However, this review paper presents data for the first time on the often ignored potential of check dams mitigating climate-induced hydrological threats. We hope that the scientific analysis presented in this paper will promote further research on check dams worldwide to better comprehend their eco-friendly significance serving society.

  7. Computational Aspects of Dam Risk Analysis: Findings and Challenges

    Directory of Open Access Journals (Sweden)

    Ignacio Escuder-Bueno

    2016-09-01

    Full Text Available In recent years, risk analysis techniques have proved to be a useful tool to inform dam safety management. This paper summarizes the outcomes of three themes related to dam risk analysis discussed in the Benchmark Workshops organized by the International Commission on Large Dams Technical Committee on “Computational Aspects of Analysis and Design of Dams.” In the 2011 Benchmark Workshop, estimation of the probability of failure of a gravity dam for the sliding failure mode was discussed. Next, in 2013, the discussion focused on the computational challenges of the estimation of consequences in dam risk analysis. Finally, in 2015, the probability of sliding and overtopping in an embankment was analyzed. These Benchmark Workshops have allowed a complete review of numerical aspects for dam risk analysis, showing that risk analysis methods are a very useful tool to analyze the risk of dam systems, including downstream consequence assessments and the uncertainty of structural models.

  8. Lac Courte Oreilles Hydro Dam Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, Jason [Lac Courte Oreilles, Hayward, WI (United States); Meyers, Amy [Kiser Hydro, LLC, Norway, MI (United States)

    2014-12-31

    The main objective of this project was to investigate upgrading the existing hydro power generating system at the Winter Dam. The tribe would like to produce more energy and receive a fair market power purchase agreement so the dam is no longer a drain on our budget but a contributor to our economy. We contracted Kiser Hydro, LLC Engineering for this project and received an engineering report that includes options for producing more energy with cost effective upgrades to the existing turbines. Included in this project was a negotiation of energy price sales negotiations.

  9. Research on Dam Perspective Based on Numerical Solution

    Institute of Scientific and Technical Information of China (English)

    WANGZi-ru; ZHOUHui-cheng; LIMing-qiu

    2005-01-01

    The numerical solution of dam toe line is solved based on the dam data and topographic map of dam located. The display of dam perspective is also realized by programming of using VC++ and OpenGL. The research results above provide the foundation of construction design, construction lofting and information inquiry, which avoids the drawbacks of only using blueprints to do the same work in the past. The method used is useful in practical engineering.

  10. ARCH-M模型的经验似然估计%Empirical likelihood estimation for ARCH-M models

    Institute of Scientific and Technical Information of China (English)

    孙岩; 李元

    2012-01-01

    This paper deals with the metric of risk aversion.Test statistics are constructed by the empirical likelihood method.Under mild conditions,asymptotic x2 distributions of test statistics are obtained,based on which confidence regions for risk aversion are given.Simulations show that the empirical likelihood method behaves well.%基于ARCH-M模型研究市场总体风险厌恶的度量问题.首先应用经验似然方法构造了检验统计量,并在一定的条件下,证明了所构造的统计量的渐近分布为卡方分布,在此基础上构造了市场总体风险厌恶的置信区间.模拟结果表明,经验似然方法表现良好.

  11. Major dams of the United States, Geographic NAD83, USGS (2006) [dams00x020_USGS_2006

    Data.gov (United States)

    Louisiana Geographic Information Center — This map layer portrays major dams of the United States, including Puerto Rico and the U.S. Virgin Islands. The map layer was created by extracting dams 50 feet or...

  12. 43 CFR 418.18 - Diversions at Derby Dam.

    Science.gov (United States)

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Diversions at Derby Dam. 418.18 Section... Operations and Management § 418.18 Diversions at Derby Dam. (a) Diversions of Truckee River water at Derby Dam must be managed to maintain minimum terminal flow to Lahontan Reservoir or the Carson River...

  13. 25 CFR 173.16 - Reserved area, Coolidge Dam.

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Reserved area, Coolidge Dam. 173.16 Section 173.16... area, Coolidge Dam. No permit for any commercial business or other activity (except boating concessions...-fourths of a mile from the center of the Coolidge Dam, Arizona....

  14. 21 CFR 872.6300 - Rubber dam and accessories.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Rubber dam and accessories. 872.6300 Section 872...) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6300 Rubber dam and accessories. (a) Identification. A rubber dam and accessories is a device composed of a thin sheet of latex with a hole in...

  15. SEISMIC RESPONSE OF DAM WITH SOIL-STRUCTURE INTERACTION.

    Science.gov (United States)

    Bycroft, G.N.; Mork, P.N.

    1987-01-01

    An analytical solution to the response of a long trapezoidal-section dam on a foundation consisting of an elastic half-space and subjected to simulated earthquake motion is developed. An optimum seismic design is achieved when the cross section of the dam is triangular. The effect of soil structure interaction is to lower the strain occurring in the dam.

  16. 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.

  17. Maxillary Arch Dimension Changes of 3-5 Years Old Filipino Children

    Directory of Open Access Journals (Sweden)

    Abdol Hamid Zafarmand

    2014-11-01

    Full Text Available Background: The purpose of this study was to assess the dental arch dimensions in primary dentition of 3-5 years old Filipino children and determining the existence of sexual dimorphism.Materials and Methods: In this descriptive study, 60 Filipino preschool children aged 3-5 years old were selected from Manila city. Study casts were used for measurements of 3 arch dimensions: bicanine width, bimolar width, and arch length. The analyses were performed to compare values within age-groups and within gender-groups, besides reporting mean and standard deviations. The data were subjected to One-way ANOVA and Student t-test.Results: Significant differences were observed regarding dental arch dimensions among different ages and genders (p<0.05. Comparison between genders showed a statistically significant difference in bicanine width at the age of 4 (p=0.04, in bimolar width at age of 5 (p=0.006, and in arch length at age of 4 (p=0.03 and 5 (p=0.02. Differences within male group for different ages showed only arch length dimension was statistically significant (p=0.021. In females, however the comparison between age-groups also revealed a statistically significant difference in bicanine (p= 0.016 and bimolar widths (p=0.027 dimensions.Conclusion: The present study showed that dental arch dimensions, vary among different ages and genders of children. It also showed that a sexual dimorphism does exist between the gender groups.

  18. 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.

  19. 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.

  20. The expected collapse of a large dam Saddam Dam in Iraq; Un grand barrage a haut risque Saddam Dam en Irak

    Energy Technology Data Exchange (ETDEWEB)

    Mesny, M. [Conseil general du genie rural, des eaux et des forets, 75 - Paris (France)

    2004-07-01

    The Saddam dam is a very large dam in Iraq on the Tigris River, 80 kilometres upstream from the city of Mosul. It is a fill dam with a clayey silt core. The height of the dam is 120 meters and the capacity of the reservoir is 11 billions m3. But this dam has been built on foundations of gypsum that is a rock soluble in water. The impounding of the reservoir in 1986 has shown that, in spite of the grout curtain, substantial seepage has occurred (up to 1.4 m{sup 3}/s), as well as the dissolution of minerals from foundations (up to 80 tons per day). The substantial increase in permeability and seepage through the dam foundations results in a severe concern about the stability of the dam. The program of injection has been stopped in 1991, due to the circumstances. So there is a real risk that this dam would collapse through a quickly developing leak in the dike, resulting in the devastation of the rich agricultural valley of the Tigris River and in potential human losses at Mosul. A 10 to 20-meter high submersion wave would reach this town 3 to 4 hours after the collapse of the dam. An international action is urgently required to check the conditions of the dam and to propose remedial solutions, which may be a 120-meter deep concrete wall down to the calcareous floor existing below the soluble layers of the foundations. (author)

  1. Dams life. Dams in operation; La vie des barrages. Barrages en exploitation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    This paper summarizes the conclusions of the annual inspections of French dams in operation (fissures, water oozing, concrete swelling etc..). Only the observations which require a special attention are reported. (J.S.)

  2. DAM-LAKEFRONT PLAZA: Revitalization of an Agriculture Reservoir Dam in Kashar-Tirana/Albania

    Directory of Open Access Journals (Sweden)

    Valbona Koçi

    2014-12-01

    Full Text Available The Dam-Lakefront Plaza in Kashar-Tirana/Albania is a research project that proposes not only the re-consideration and reinforcement of the artificial Reservoirs Dams built during Socialism in Albania, but envisions the maintenance of dams and revitalization of the lakeside area promoting the public-private collaboration. In addition, it envisions the generation of qualitative and lively public spaces in sub-urban areas as well. Admitting the artificial lakes as specific nodes of man-made infrastructure in the landscape, and consequently the dams (together with the drainage channels as important hydrotechnic elements of the flood protection infrastructure, this research intends to elaborate on one type of landscape infrastructure - the vertical screens, offering a mediation between the natural and built landscape.

  3. Feeding an infant with high arched palate by high flow rate bottle nipple.

    Science.gov (United States)

    Eren, Abdulkadir; Bilgin, Huseyin; Kara, Semra

    2015-01-01

    For infants with high arched palate, feeding is one of the most immediate challenges faced by parents and caretakers. General suggestions for feeding in infants with cleft palate may be adapted to infants with high arched palate. These include oral feeding facilitation techniques and special feeding tools. Here we present a newborn with a high arched palate and serious feeding problems who was fed easily by a large size and a large hole nipple, ordinarily used for infants older than 6 months, instead of specialized feeding equipment.

  4. Axillary artery counter-current aortography in the newborn with aortic arch obstruction

    Energy Technology Data Exchange (ETDEWEB)

    Lau, K.C.; Lo, R.N.S.; Leung, M.P.

    1989-08-01

    13 newborn infants with aortic coarctation were evaluated by counter-current aortographic technique. The right radial or brachial artery approach (2 cases in each group) did not give successful aortic arch imaging while the right axiallary artery approach resulted in adequate imaging in each of 9 cases investigated. In 2, the axillary artery was transiently weakened but returned to normal within 24 hours. No other complications were encountered. Axillary artery counter-current aortography is a safe and relatively non-invasive procedure which can be used to image the aortic arch in the newborn babies when other non-invasive diagnosis of aortic arch obstruction is tentative. (orig.).

  5. Experimental research on the dam-break mechanisms of the Jiadanwan landslide dam triggered by the Wenchuan earthquake in China.

    Science.gov (United States)

    Xu, Fu-gang; Yang, Xing-guo; Zhou, Jia-wen; Hao, Ming-hui

    2013-01-01

    Dam breaks of landslide dams are always accompanied by large numbers of casualties, a large loss of property, and negative influences on the downstream ecology and environment. This study uses the Jiadanwan landslide dam, created by the Wenchuan earthquake, as a case study example. Several laboratory experiments are carried out to analyse the dam-break mechanism of the landslide dam. The different factors that impact the dam-break process include upstream flow, the boulder effect, dam size, and channel discharge. The development of the discharge channel and the failure of the landslide dam are monitored by digital video and still cameras. Experimental results show that the upstream inflow and the dam size are the main factors that impact the dam-break process. An excavated discharge channel, especially a trapezoidal discharge channel, has a positive effect on reducing peak flow. The depth of the discharge channel also has a significant impact on the dam-break process. The experimental results are significant for landslide dam management and flood disaster prevention and mitigation.

  6. Socioeconomic and Institutional Dimensions of Dam Removals: The Wisconsin Experience

    Science.gov (United States)

    Born; Genskow; Filbert; Hernandez-Mora; Keefer; White

    1998-05-01

    / There are tens of thousands of small dams in the United States; many of these aging structures are deteriorating. Governments and dam owners face decisions regarding repair or removal of these structures. Along with the many benefits society derives from dams and their impoundments, numerous recent ecological studies are revealing the extensive alteration and degradation of river ecosystems by dams. Dam removal-a principal restoration strategy-is an infrequent event. The major reasons for removal have been public safety and the high costs associated with repair; the goal of river ecosystem restoration now warrants greater attention. Substantial study is being given to the environmental aspects of dams and dam removals, but very little attention has been given to the socioeconomic and institutional dimensions associated with the removal of dams, although these factors play a significant role in the removal decision-making process. Based on a case study of dam removals in Wisconsin-where more than 30 of the state's 3600 small dams have been removed in the past few decades-legal, financial, and socioeconomic issues associated with dam removal are documented and assessed. Dam removal has been complex and contentious, with limited community-based support for removal and loss of the impounded waters. In cases examined here, the estimated costs of repairing a dam averaged more than three times the cost of removal. The availability of governmental financing has been a key determinant in removal decisions. Watershed-scale ecological considerations are not major factors for most local interests. As watershed management and restoration increasingly include dam removal options as part of an integrated strategy, more attention will need to be focused on socioeconomic factors and stakeholder perspectives-variables that strongly influence the viability of this management alternative.KEY WORDS: Dam removal; River restoration; Institutions; Stakeholders

  7. River restoration by dam removal: Enhancing connectivity at watershed scales

    Directory of Open Access Journals (Sweden)

    F.J. Magilligan

    2016-05-01

    Full Text Available Abstract The prolonged history of industrialization, flood control, and hydropower production has led to the construction of 80,000 dams across the U.S. generating significant hydrologic, ecological, and social adjustments. With the increased ecological attention on re-establishing riverine connectivity, dam removal is becoming an important part of large-scale river restoration nationally, especially in New England, due to its early European settlement and history of waterpower-based industry. To capture the broader dimensions of dam removal, we constructed a GIS database of all inventoried dams in New England irrespective of size and reservoir volume to document the magnitude of fragmentation. We compared the characteristics of these existing dams to the attributes of all removed dams over the last ∼25 years. Our results reveal that the National Inventory of Dams significantly underestimates the actual number of dams (4,000 compared to >14,000. To combat the effects of these ecological barriers, dam removal in New England has been robust with 127 dams having been removed between ca. 1990–2013. These removed dams range in size, with the largest number (30% ranging between 2–4 m high, but 22% of the removed dams were between 4–6 m. They are not isolated to small drainage basins: most drained watersheds between 100–1,000 km2. Regionally, dam removal has re-connected ∼3% (3,770 river km of the regional river network although primarily through a few select dams where abundant barrier-free river lengths occur, suggesting that a more strategic removal approach has the opportunity to enhance the magnitude and rate of river re-connection. Given the regional-scale restoration of forest cover and water quality over the past century, dam removal offers a significant opportunity to capitalize on these efforts, providing watershed scale restoration and enhancing watershed resilience in the face of significant regional and global anthropogenic

  8. Increasing dam safety with multi beam sonar

    Energy Technology Data Exchange (ETDEWEB)

    Bartsch, M. [SwedPower AB, Stockholm (Sweden); Cederstrom, M.O. [Vattenfall AB, Stockholm (Sweden); Deborg, J. [SwedPower AB, Alvkarleby (Sweden)

    2004-09-01

    Multi-beam sonar technology has been introduced to Vattenfall's dam safety program. Vattenfall is the major energy producer in Sweden and the third largest utility in Europe. Embankment dams are subject to processes such as erosion, settlement and sinkholes. The new portable multi-beam echo sounder system is an important tool to detect minor damages and to intervene before they evolve into expensive or hazardous situations. A first survey of the upstream slope of a rockfill dam with this method provides a topographic map indicating the location of anomalies such as internal erosion or piping. Multi-beam sonar works by combining GPS-RTK positioning, gyro motion sensing, a multi-beam sonar and 3-dimensional digital terrain programs. Vattenfall is using the system to verify and monitor all high hazard rockfill dams in Sweden to ensure long-term stability. The data will be stored as a fingerprint for comparison with future surveys in 15 to 20 years as part of routine safety evaluation. This new technology can also be used to survey breakwaters, erosion of rivers and to locate submerged debris in harbours. 6 figs.

  9. Will We. . .? Thai Dam Resource Book.

    Science.gov (United States)

    Murphy, Richard, Ed.; And Others

    This resource book is intended as an aid to persons working with Thai Dam refugees. To help the language teacher, some differences between Lao and English are discussed, specifically tonal inflections, positioning, declension of pronouns, conjugation of verbs, interrogatives, classifiers and predicate adjectives. An outline of cultural differences…

  10. A Final Test for the Big Dam

    Institute of Scientific and Technical Information of China (English)

    LI LI

    2010-01-01

    @@ The water level at the Three Gorges Dam,the world's largest water control and utilization project,reached its designed highest mark on October 26,which will enable the project to fulfill its functions of flood control,power generation,navigation and water diversion.

  11. Aquifer performance under the Mactaquac Dam

    Energy Technology Data Exchange (ETDEWEB)

    Tawil, A.H. [Acres International, Niagara Falls, ON (Canada); Harriman, F.B. [New Brunswick Power, Fredericton, NB (Canada)

    2001-10-01

    The highest dam in the whole of the Maritimes and New Brunswick in particular is the Mactaquac Dam, with a height of 58 m above the foundation. It forms an integral part of the Mactaquac Hydroelectric Development and the construction of the dam was completed in 1967. Composed of a central core of clay till and external shells of rockfill, it is a zoned embankment. The high artesian pressure rising 6 m above the Saint John River dominates, and the foundation under the dam is composed of a stratum of stiff glacial till underlain with a thick, water bearing aquifer. The aquifer needed to be depressurized during the construction phase and in the long term, and special measures were required to accomplish this. Measurements obtained over a period exceeding 30 years were used to describe the performance of the aquifer, which is discussed in this presentation. A continuous reduction in the yield from the six permanent relief wells in the aquifer was indicated by the instrumentation data. The outflow from the wells diminished by two-thirds over the thirty-four years since first filling the reservoir. The piezometric pressure in the aquifer remained constant over the same period. The sparse results of a two-hour pump test had formed the basis for the design decision not to install a costly foundation seepage cut-off to bedrock, as the conclusions drawn from the pump test were that the aquifer was hydrogeologically confined. 3 refs., 4 tabs., 9 figs.

  12. Modelling approach for gravity dam break analysis

    Directory of Open Access Journals (Sweden)

    Boussekine Mourad

    2016-09-01

    Full Text Available The construction of dams in rivers can provide considerable benefits such as the supply of drinking and irrigation water; however the consequences which would result in the event of their failure could be catastrophic. They vary dramatically depending on the extent of the inundation area, the size of the population at risk.

  13. 75 FR 49429 - Metal and Nonmetal Dams

    Science.gov (United States)

    2010-08-13

    ...? Please provide details such as hours, rates of pay, job titles, and any contractual services necessary. How often is the design of an existing dam changed? What are the costs of a redesign? 27. What are the..., rates of pay, job titles; costs of equipment and materials; and any contractual services necessary....

  14. 7 CFR 1724.55 - Dam safety.

    Science.gov (United States)

    2010-01-01

    ... result from encountering unanticipated or unusual conditions during construction. (5) The independent review of construction shall include: (i) Foundation preparation and treatment. When the foundation has... construction. The reviewer must have demonstrated experience in the design and construction of dams of...

  15. Fish reproductive guilds downstream of dams.

    Science.gov (United States)

    Vasconcelos, L P; Alves, D C; Gomes, L C

    2014-11-01

    Fish reproductive guilds were used to evaluate the responses of species with different reproductive strategies during two different periods of post-dam construction. The data used for the comparisons were collected in the upper Paraná River floodplain (Brazil), downstream of the Porto Primavera dam, 2 and 10 years after impoundment. The abundance (catch per unit effort, CPUE), species richness, evenness and structure of communities, all within reproductive guilds, were used to test the hypothesis that these metrics vary spatially and temporally. The influence of damming on species structure and the diversity of fish reproductive guilds varied spatiotemporally, and species with opportunistic reproductive strategies tended to be less affected. Conversely, long-distance migratory species responded more markedly to spatiotemporal variations, indicating that the ecosystem dynamics exert greater effects on populations of these species. Thus, the effects of a dam, even if attenuated, may extend over several years, especially downstream. This finding emphasizes the importance of maintaining large undammed tributaries downstream of reservoirs.

  16. RESEARCH ON SEEPAGE MONITORING MODEL OF EARTH-ROCK DAM

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    With the characteristics of seepage flow in earth-rock dams, a seepage monitoring model was established based on the finite element method for 3-D seepage flow together with observed data and was used to analyze and monitor the seepage of dams. In order to find out and monitor the seepage status of the whole dam, the separation of seepage amount for dam body, dam foundation and side banks was made theoretically by using the model. Practical example shows that the accuracy of computed results is satisfactory and the separation results are more objective.

  17. 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.

  18. Mining dams safety regulations : where does Canada stand?

    Energy Technology Data Exchange (ETDEWEB)

    Priscu, C. [AMEC, Winnipeg, MB (Canada); Small, A. [AMEC Earth and Environmental Ltd., Fredericton, NB (Canada); Lupo, J. [AMEC, Englewood, CO (United States); Diaz, M. [AMEC, Ashford, Kent (United Kingdom); Davies, M. [AMEC, Vancouver, BC (Canada); Musse, M. [AMEC, Santiago (Chile)

    2009-07-01

    While many jurisdictions in Canada use the Canadian Dam Association (CDA) dam safety guidelines, their applicability to the safety of mining dams is limited. Mining dams are some of the largest containment structures in the world, and impound millions of cubic meters of mine process residues in both solid and liquid form. This study presented a review of dam safety regulatory frameworks for mining dams located in various countries. The aim of the study was to compare the Canadian framework with various dam safety legislations in order to evaluate Canada's current status and recommend best practices in dam safety regulations. The study reviewed incremental consequence classifications; best practices in operation, surveillance and maintenance manuals and procedures; emergency preparedness plans; and dam safety inspections. The study showed that Canada has limited documentation regulating the safe management of tailings facilities, and does not have an all-encompassing national guideline for mining dams. It was concluded that an incremental consequence classification (ICC) system should be developed specifically for mining dams. 12 refs.

  19. Seismic failure modes and seismic safety of Hardfill dam

    Directory of Open Access Journals (Sweden)

    Kun XIONG

    2013-04-01

    Full Text Available Based on microscopic damage theory and the finite element method, and using the Weibull distribution to characterize the random distribution of the mechanical properties of materials, the seismic response of a typical Hardfill dam was analyzed through numerical simulation during the earthquakes with intensities of 8 degrees and even greater. The seismic failure modes and failure mechanism of the dam were explored as well. Numerical results show that the Hardfill dam remains at a low stress level and undamaged or slightly damaged during an earthquake with an intensity of 8 degrees. During overload earthquakes, tensile cracks occur at the dam surfaces and extend to inside the dam body, and the upstream dam body experiences more serious damage than the downstream dam body. Therefore, under the seismic conditions, the failure pattern of the Hardfill dam is the tensile fracture of the upstream regions and the dam toe. Compared with traditional gravity dams, Hardfill dams have better seismic performance and greater seismic safety.

  20. Dam failure analysis for the Lago El Guineo Dam, Orocovis, Puerto Rico

    Science.gov (United States)

    Gómez-Fragoso, Julieta; Heriberto Torres-Sierra,

    2016-08-09

    The U.S. Geological Survey, in cooperation with the Puerto Rico Electric Power Authority, completed hydrologic and hydraulic analyses to assess the potential hazard to human life and property associated with the hypothetical failure of the Lago El Guineo Dam. The Lago El Guineo Dam is within the headwaters of the Río Grande de Manatí and impounds a drainage area of about 4.25 square kilometers.The hydrologic assessment was designed to determine the outflow hydrographs and peak discharges for Lago El Guineo and other subbasins in the Río Grande de Manatí hydrographic basin for three extreme rainfall events: (1) a 6-hour probable maximum precipitation event, (2) a 24-hour probable maximum precipitation event, and (3) a 24-hour, 100-year recurrence rainfall event. The hydraulic study simulated a dam failure of Lago El Guineo Dam using flood hydrographs generated from the hydrologic study. The simulated dam failure generated a hydrograph that was routed downstream from Lago El Guineo Dam through the lower reaches of the Río Toro Negro and the Río Grande de Manatí to determine water-surface profiles developed from the event-based hydrologic scenarios and “sunny day” conditions. The Hydrologic Engineering Center’s Hydrologic Modeling System (HEC–HMS) and Hydrologic Engineering Center’s River Analysis System (HEC–RAS) computer programs, developed by the U.S. Army Corps of Engineers, were used for the hydrologic and hydraulic modeling, respectively. The flow routing in the hydraulic analyses was completed using the unsteady flow module available in the HEC–RAS model.Above the Lago El Guineo Dam, the simulated inflow peak discharges from HEC–HMS resulted in about 550 and 414 cubic meters per second for the 6- and 24-hour probable maximum precipitation events, respectively. The 24-hour, 100-year recurrence storm simulation resulted in a peak discharge of about 216 cubic meters per second. For the hydrologic analysis, no dam failure conditions are

  1. 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

  2. Gabcikovo dam and Liptovska Mara dam - statistical analysis of measurement data

    Science.gov (United States)

    Hakac, J.; Sabo, M.

    2012-04-01

    Introduction: Water level in the observation wells is measured regularly and one of the reasons is evaluation of the safety of the water constructions. In this paper we are exploring the reliability of the measuring devices that are responsible for evaluation of the safety of the two largest and the most important dams in Slovakia. We test ability of selected statistical methods to detect early inaccuracies of measuring devices and thus improve the evaluation of the safety of the water constructions. As a follow-up study, we used the time series model (Neural network) to predict water levels in the observation wells that were considered to be without defects. Neural Network is also able to show dynamics of the filtration stability of the observational well. Methods: On the Liptovska Mara dam weekly data was used as a monitoring tool. On the Gabcikovo dam five minute time series of the measurements of the water level in observation wells around the right lock chamber were used. Data from the measuring devices of the dams were explored with boxplots, correlations, neural network, etc. The mentioned statistical tools analyze time series and detect the errors that measuring devices make when generating data and can be used to predict errors even in real time. In the second step, agreement between predicted data from neural network and measured data in the real time was evaluated. We used grid search for finding the optimal number of neurons and then predicted errors by using this model. The ability of the neural network in evaluation of the sealing of the dilatation joints on the filtration stability in the years 2009 - 2011 is presented. Results: From the 18 selected measuring devices on the Liptovska Mara dam there are only 3 devices which can be considered as reliable. On the Gabcikovo dam, 8 of 9 measuring devices (observation wells around right lock chamber) were considered as a reliable. There was very good agreement between the predicted and measured data at the

  3. Effects of Asthma and Inhalation corticosteroids on the dental arch morphology in children

    Directory of Open Access Journals (Sweden)

    S S Kumar

    2012-01-01

    Full Text Available Background: Hereditary, environmental and developmental factors play an important role in dentofacial development, as well as the initiation of malocclusion disorder. Allergic phenomenon such as asthma that induces an alternative mode of breathing in patients is a contributing factor in development of the dental arch. Aim: Our aim in this study was to evaluate the dentoalveolar morphology in asthmatic children and to analyze the effects of asthmatic medications on the dental arch. Setting and Design : This study is centered on 44 asthmatic children aged between 6-12 years from J.S.S Hospital, Mysore. Selected variables from model analysis of the casts of the asthmatic group were subjected to comparison with those of the non-asthmatic group, which comprised of 44 non-asthmatic children. Selected parameters were arch width, arch length and palatal depth. Materials and Methods : Impressions of upper and lower arches were made with rubber based impression material. A sliding digital caliper was used to measure the casts for arch width and arch length. A palatal depth gauge was used to measure the palatal depth. Statistical Analysis : Differences in arch widths, arch lengths and palatal depths between asthmatics and non-asthmatics groups were evaluated by independent sample t-tests. Chi-square test was applied to assess the frequency of occurrence of malocclusion in the asthmatic children. Result: The results obtained revealed that the arch length and palatal depth of asthmatic group had higher values compared to that of non-asthmatic groups for both age groups (6 to 8-year-old males and females, 10 to 12-year-old males and females. Inter molar width showed a significant lower value in asthmatics in the maxillary arches of 10 to 12-year-old females. Fifty percent of the asthmatic children aged 10 to 12-years had open-bite. Children under regular medication showed significant deviation in the dentoalveolar morphology as compared to those under

  4. 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.

  5. 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.

  6. Role of Soil Hysteresis in Impedance Testing as Applied to Buried Arches

    Science.gov (United States)

    1990-02-01

    information . I Add the individual listed to your distribution list. [] Delete the cited organization/individual. El Change of address. NAME: ORGANIZATION...arch structure shows that the backfill soil hysteretic behavoir is a dominant factor in explaining the absence of resonance in arch tests. ~ n0...TECHNICAL INFORMATION CENTER ATTN: ASMS 2CYS ATTN: DTIC/FDAB ATTN: MYE STRATEGIC AND THEATER NUCLEAR FORCES WEAPONS LABORATORY ATTN: DR E SEVIN ATTN

  7. Novel technique for arch and visceral artery debranching using ascending aortic inflow.

    Science.gov (United States)

    Mussa, Firas F; Walkes, Jon-Cecil; Lumsden, Alan B; Reardon, Michael J

    2008-01-01

    Aortic arch aneurysms extending proximally to the left subclavian artery have traditionally been approached through a median sternotomy and a staged elephant trunk procedure requiring a left thoracotomy or thoracoabdominal incision. We describe a novel technique for repair of such aneurysms in a single-stage, hybrid approach using bypass grafts arising from the ascending aorta to all arch and upper abdominal visceral arteries followed by endovascular exclusion of the aortic aneurysm.

  8. Goldenhar syndrome with right circumflex aortic arch, severe coarctation and vascular ring in a twin pregnancy

    Directory of Open Access Journals (Sweden)

    Elaheh Malakan Rad

    2014-01-01

    Full Text Available Goldenhar syndrome (GS or oculo-auriculo-vertebral dysplasia (OAVD, involves a wide variety of organ systems. Cardiovascular anomalies are among the frequent malformations. The purpose of this report is to introduce a male case of a dizygotic twin pregnancy with GS and right circumflex aortic arch (RCAA, severe coarctation, hypoplastic aortic arch, aberrant right subclavian artery, vascular ring, bilateral renal artery stenosis, and mild Dandy-Walker syndrome. The embryology of RCAA and coarctation is revisited.

  9. Goldenhar syndrome with right circumflex aortic arch, severe coarctation and vascular ring in a twin pregnancy

    OpenAIRE

    Elaheh Malakan Rad

    2014-01-01

    Goldenhar syndrome (GS) or oculo-auriculo-vertebral dysplasia (OAVD), involves a wide variety of organ systems. Cardiovascular anomalies are among the frequent malformations. The purpose of this report is to introduce a male case of a dizygotic twin pregnancy with GS and right circumflex aortic arch (RCAA), severe coarctation, hypoplastic aortic arch, aberrant right subclavian artery, vascular ring, bilateral renal artery stenosis, and mild Dandy-Walker syndrome. The embryology of RCAA and co...

  10. Goldenhar syndrome with right circumflex aortic arch, severe coarctation and vascular ring in a twin pregnancy.

    Science.gov (United States)

    Rad, Elaheh Malakan

    2014-09-01

    Goldenhar syndrome (GS) or oculo-auriculo-vertebral dysplasia (OAVD), involves a wide variety of organ systems. Cardiovascular anomalies are among the frequent malformations. The purpose of this report is to introduce a male case of a dizygotic twin pregnancy with GS and right circumflex aortic arch (RCAA), severe coarctation, hypoplastic aortic arch, aberrant right subclavian artery, vascular ring, bilateral renal artery stenosis, and mild Dandy-Walker syndrome. The embryology of RCAA and coarctation is revisited.

  11. Goldenhar syndrome with right circumflex aortic arch, severe coarctation and vascular ring in a twin pregnancy

    Science.gov (United States)

    Rad, Elaheh Malakan

    2014-01-01

    Goldenhar syndrome (GS) or oculo-auriculo-vertebral dysplasia (OAVD), involves a wide variety of organ systems. Cardiovascular anomalies are among the frequent malformations. The purpose of this report is to introduce a male case of a dizygotic twin pregnancy with GS and right circumflex aortic arch (RCAA), severe coarctation, hypoplastic aortic arch, aberrant right subclavian artery, vascular ring, bilateral renal artery stenosis, and mild Dandy-Walker syndrome. The embryology of RCAA and coarctation is revisited. PMID:25298700

  12. 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.

  13. Correlation Between Maxillary Central Incisor Crown Morphology And Mandibular Dental Arch Form In Normal Occlusion Subjects

    OpenAIRE

    Paranhos, Luiz Renato; Lima,Carolina Souto; Silva,Ricardo Henrique Alves da; 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 ob...

  14. 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.

  15. Development of the human aortic arch system captured in an interactive three-dimensional reference model.

    Science.gov (United States)

    Rana, M Sameer; Sizarov, Aleksander; Christoffels, Vincent M; Moorman, Antoon F M

    2014-06-01

    Variations and mutations in the human genome, such as 22q11.2 microdeletion, can increase the risk for congenital defects, including aortic arch malformations. Animal models are increasingly expanding our molecular and genetic insights into aortic arch development. However, in order to justify animal-to-human extrapolations, a human morphological, and molecular reference model would be of great value, but is currently lacking. Here, we present interactive three-dimensional reconstructions of the developing human aortic arch system, supplemented with the protein distribution of developmental markers for patterning and growth, including T-box transcription factor TBX1, a major candidate for the phenotypes found in patients with the 22q11.2 microdeletion. These reconstructions and expression data facilitate unbiased interpretations, and reveal previously unappreciated aspects of human aortic arch development. Based on our reconstructions and on reported congenital anomalies of the pulmonary trunk and tributaries, we postulate that the pulmonary arteries originate from the aortic sac, rather than from the sixth pharyngeal arch arteries. Similar to mouse, TBX1 is expressed in pharyngeal mesenchyme and epithelia. The endothelium of the pharyngeal arch arteries is largely negative for TBX1 and family member TBX2 but expresses neural crest marker AP2α, which gradually decreases with ongoing development of vascular smooth muscle. At early stages, the pharyngeal arch arteries, aortic sac, and the dorsal aortae in particular were largely negative for proliferation marker Ki67, potentially an important parameter during aortic arch system remodeling. Together, our data support current animal-to-human extrapolations and future genetic and molecular analyses using animal models of congenital heart disease. © 2013 Wiley Periodicals, Inc.

  16. [Interrupted aortic arch in a 68-year-old female with hypertension].

    Science.gov (United States)

    Benincasa, Susanna; Fineschi, Massimo; Ceccherini, Claudio; Pierli, Carlo

    2015-04-01

    Interrupted aortic arch (IAA) is a rare congenital malformation of the aorta and aortic arch. We report the case of a 68-year-old female with hypertension and poor control of blood pressure levels. She was diagnosed with aortic coarctation by aortography during young age. A double access angiography was performed that showed a type A IAA, a rare condition in adults that may cause hypertension.

  17. 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.

  18. 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...

  19. Behaviour of Frictional Joints in Steel Arch Yielding Supports

    Science.gov (United States)

    Horyl, Petr; Šňupárek, Richard; Maršálek, Pavel

    2014-10-01

    The loading capacity and ability of steel arch supports to accept deformations from the surrounding rock mass is influenced significantly by the function of the connections and in particular, the tightening of the bolts. This contribution deals with computer modelling of the yielding bolt connections for different torques to determine the load-bearing capacity of the connections. Another parameter that affects the loading capacity significantly is the value of the friction coefficient of the contacts between the elements of the joints. The authors investigated both the behaviour and conditions of the individual parts for three values of tightening moment and the relation between the value of screw tightening and load-bearing capacity of the connections for different friction coefficients. ANSYS software and the finite element method were used for the computer modelling. The solution is nonlinear because of the bi-linear material properties of steel and the large deformations. The geometry of the computer model was created from designs of all four parts of the structure. The calculation also defines the weakest part of the joint's structure based on stress analysis. The load was divided into two loading steps: the pre-tensioning of connecting bolts and the deformation loading corresponding to 50-mm slip of one support. The full Newton-Raphson method was chosen for the solution. The calculations were carried out on a computer at the Supercomputing Centre VSB-Technical University of Ostrava.

  20. 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.

  1. PDR Emission from the Arched-Filaments and Nearby Positions

    CERN Document Server

    García, P; Abel, N; Steinke, M; Burton, M; Blackwell, R

    2016-01-01

    We investigate the physical conditions of the gas, atomic and molecular, in the filaments in the context of Photo-Dissociation Regions (PDRs) using the KOSMA-PDR mode of clumpy clouds. We also compare the [CII] vs. [NII] integrated intensity predictions in Abel et al. 2005 for HII regions and adjacent PDRs in the Galactic disk, and check for their applicability under the extreme physical conditions present in the GC. Our preliminary results show that observed integrated intensities are well reproduced by the PDR model. The gas is exposed to a relatively low Far-UV field between 10^2 - 10^3 Draine fields. The total volume hydrogen density is well constrained between 10^4 - 10^5 cm^-3. The hydrogen ionization rate due to cosmic-rays varies between 10^-15 and 4x10^-15 s^-1, with the highest value ~ 10^-14 s^-1 found towards G0.07+0.04. Our results show that the line-of-sight contribution to the total distance of the filaments to the Arches Cluster is not negligible. The spatial distribution of the [CII]/[NII] ra...

  2. Damned If You Do, Dammed If You Don't: Debates on Dam Removal in the Swedish Media

    Directory of Open Access Journals (Sweden)

    Dolly Jørgensen

    2013-03-01

    Full Text Available Dam removal is an increasingly common practice. Dams are removed for various reasons, with safety, economics, and ecosystem restoration being the most common. However, dam removals often cause controversy. Riparian land owners and local communities often have a negative view of removal, and their reasons vary. It may be the loss of recreational benefits such as swimming and boating, loss of cultural and historical context tied to the dam, or fear that removal may have a negative effect on aesthetic values. Because controversies are often picked up by local media, and media in itself is an important channel to build support around a cause, the way in which dam removals are reported and discussed in the media is likely to influence the debate. Here, we examine the ways in which proponents and opponents of dam removal frame the services provided by two contrasting ecosystems, i.e., an existing dam and the potential stream without a dam, by performing a media discourse analysis of the reasons given for removal and the reasons presented for the dam to remain in place. Our source material includes Internet-based newspaper articles and their associated public comments in four dam removal controversies in Sweden. Our analysis indicates that public opposition is not based on knowledge deficiency, where more information will lead to better ecological decision-making, as is sometimes argued in dam removal science; it is instead a case of different understandings and valuation of the environment and the functions it provides.

  3. Dam-breach analysis and flood-inundation mapping for selected dams in Oklahoma City, Oklahoma, and near Atoka, Oklahoma

    Science.gov (United States)

    Shivers, Molly J.; Smith, S. Jerrod; Grout, Trevor S.; Lewis, Jason M.

    2015-01-01

    Dams provide beneficial functions such as flood control, recreation, and storage of water supplies, but they also entail risk; dam breaches and resultant floods can cause substantial property damage and loss of life. The State of Oklahoma requires each owner of a high-hazard dam, which the Federal Emergency Management Agency defines as dams for which failure or improper operation probably will cause loss of human life, to develop an emergency action plan specific to that dam. Components of an emergency action plan are to simulate a flood resulting from a possible dam breach and map the resulting downstream flood-inundation areas. The resulting flood-inundation maps can provide valuable information to city officials, emergency managers, and local residents for planning an emergency response if a dam breach occurs.

  4. National Dam Inspection Program. Lake Housatonic Dam and Dike (CT 00026 and CT 01714). Connecticut Coastal Basin, Housatonic River, Derby-Shelton, Connecticut. Phase I Inspection Report.

    Science.gov (United States)

    1981-08-01

    8217;’,.-+-.-. ""’"" . .•• "•;. - NATIONAL DAM INSPECTION PROGRAM PHASE I INSPECTION REPORT Identification No.: CT 00026, CT 01714 N *~ Name of Dam: Lake Housatonic Dam and Dike " Town...approach was used between 1868 and 1870 to strengthen the Holyoke dam. The dam that existed there at the time was a timber crib dam, 1,017 feet long and 30

  5. Ductal Stent Implantation in Tetralogy of Fallot with Aortic Arch Abnormality

    Science.gov (United States)

    Ergul, Yakup; Saygi, Murat; Ozyilmaz, Isa; Guzeltas, Alper; Odemis, Ender

    2015-01-01

    Stenting of patent ductus arteriosus is an alternative to palliative cardiac surgery in newborns with duct-dependent or decreased pulmonary circulation; however, the use of this technique in patients with an aortic arch abnormality presents a challenge. Tetralogy of Fallot is a congenital heart defect that is frequently associated with anomalies of the aortic arch and its branches. The association is even more common in patients with chromosome 22q11 deletion. We present the case of an 18-day-old male infant who had cyanosis and a heart murmur. After an initial echocardiographic evaluation, the patient was diagnosed with tetralogy of Fallot and right-sided aortic arch. The pulmonary annulus and the main pulmonary artery and its branches were slightly hypoplastic; the ductus arteriosus was small. Conventional and computed tomographic angiograms revealed a double aortic arch and an aberrant left subclavian artery. The right aortic arch branched into the subclavian arteries and continued into the descending aorta, whereas the left aortic arch branched into the common carotid arteries and ended with the patent ductus arteriosus. After evaluation of the ductal anatomy, we implanted a 3.5 × 15-mm coronary stent in the duct. Follow-up injections showed augmented pulmonary flow and an increase in oxygen saturation from 65% to 94%. The patient was also found to have chromosome 22q11 deletion. PMID:26175649

  6. 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.

  7. 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.

  8. 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.

  9. How Big of an Effect Do Small Dams Have? Using Geomorphological Footprints to Quantify Spatial Impact of Low-Head Dams and Identify Patterns of Across-Dam Variation.

    Science.gov (United States)

    Fencl, Jane S; Mather, Martha E; Costigan, Katie H; Daniels, Melinda D

    2015-01-01

    Longitudinal connectivity is a fundamental characteristic of rivers that can be disrupted by natural and anthropogenic processes. Dams are significant disruptions to streams. Over 2,000,000 low-head dams (dams on geomorphology and ecology are largely untested. Progress for research and conservation is impaired by not knowing the magnitude of low-head dam impacts. Based on the geomorphic literature, we refined a methodology that allowed us to quantify the spatial extent of low-head dam impacts (herein dam footprint), assessed variation in dam footprints across low-head dams within a river network, and identified select aspects of the context of this variation. Wetted width, depth, and substrate size distributions upstream and downstream of six low-head dams within the Upper Neosho River, Kansas, United States of America were measured. Total dam footprints averaged 7.9 km (3.0-15.3 km) or 287 wetted widths (136-437 wetted widths). Estimates included both upstream (mean: 6.7 km or 243 wetted widths) and downstream footprints (mean: 1.2 km or 44 wetted widths). Altogether the six low-head dams impacted 47.3 km (about 17%) of the mainstem in the river network. Despite differences in age, size, location, and primary function, the sizes of geomorphic footprints of individual low-head dams in the Upper Neosho river network were relatively similar. The number of upstream dams and distance to upstream dams, but not dam height, affected the spatial extent of dam footprints. In summary, ubiquitous low-head dams individually and cumulatively altered lotic ecosystems. Both characteristics of individual dams and the context of neighboring dams affected low-head dam impacts within the river network. For these reasons, low-head dams require a different, more integrative, approach for research and management than the individualistic approach that has been applied to larger dams.

  10. 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) ...

  11. Temporal and spatial distribution of dam failure events in China

    Institute of Scientific and Technical Information of China (English)

    X.Y.HE; Z.Y.WANG; J.C.HUANG

    2008-01-01

    Reservoirs play a vital role in economic development and flood control.Nevertheless,both human and natural factors may lead to dam failures with catastrophic consequences.Analyzing the data of dam failure events from 1954 to 2003 and using the method of energy spectrum analysis,this paper studies the periodicity of dam failures.The rate of failure of different dam ages is analyzed.The climate is the main factor affecting the rate of dam failure.Climate diagrams are used to analyze the spatial distribution of dam failure events in China.High rate of dam failure occurs with 25-year and 12.5-year periods.The distribution of the percentage of dam failure shows an L-shape as a function of service age.The first 5 years of operation is known as the "infant period",during which,the probability of dam failure is much higher than during any other periods.The failure rate in areas near or north to the 400 mm annual isopluvial line is notably higher than other areas.In areas with high temperature difference among seasons have a high annual average dam failure rate.

  12. Dam removal increases American eel abundance in distant headwater streams

    Science.gov (United States)

    Hitt, Nathaniel P.; Eyler, Sheila; Wofford, John E.B.

    2012-01-01

    American eel Anguilla rostrata abundances have undergone significant declines over the last 50 years, and migration barriers have been recognized as a contributing cause. We evaluated eel abundances in headwater streams of Shenandoah National Park, Virginia, to compare sites before and after the removal of a large downstream dam in 2004 (Embrey Dam, Rappahannock River). Eel abundances in headwater streams increased significantly after the removal of Embrey Dam. Observed eel abundances after dam removal exceeded predictions derived from autoregressive models parameterized with data prior to dam removal. Mann–Kendall analyses also revealed consistent increases in eel abundances from 2004 to 2010 but inconsistent temporal trends before dam removal. Increasing eel numbers could not be attributed to changes in local physical habitat (i.e., mean stream depth or substrate size) or regional population dynamics (i.e., abundances in Maryland streams or Virginia estuaries). Dam removal was associated with decreasing minimum eel lengths in headwater streams, suggesting that the dam previously impeded migration of many small-bodied individuals (dams may influence eel abundances in headwater streams up to 150 river kilometers distant, and that dam removal may provide benefits for eel management and conservation at the landscape scale.

  13. Will Dam Removal Increase Nitrogen Flux to Estuaries?

    Directory of Open Access Journals (Sweden)

    Arthur J. Gold

    2016-11-01

    Full Text Available To advance the science of dam removal, analyses of functions and benefits need to be linked to individual dam attributes and effects on downstream receiving waters. We examined 7550 dams in the New England (USA region for possible tradeoffs associated with dam removal. Dam removal often generates improvements for safety or migratory fish passage but might increase nitrogen (N flux and eutrophication in coastal watersheds. We estimated N loading and removal with algorithms using geospatial data on land use, stream flow and hydrography. We focused on dams with reservoirs that increase retention time at specific points of river reaches, creating localized hotspots of elevated N removal. Approximately 2200 dams with reservoirs had potential benefits for N removal based on N loading, retention time and depth. Across stream orders, safety concerns on these N removal dams ranged between 28% and 44%. First order streams constituted the majority of N removal dams (70%, but only 3% of those were classified as high value for fish passage. In cases where dam removal might eliminate N removal function from a particular reservoir, site-specific analyses are warranted to improve N delivery estimates and examine alternatives that retain the reservoir while enhancing fish passage and safety.

  14. Landfill liners from dam reservoir sediments

    Directory of Open Access Journals (Sweden)

    Koś Karolina

    2016-03-01

    Full Text Available Landfill liners from dam reservoir sediments. Every municipal solid waste landfill has to be properly secured to protect the natural environment from possible leachate. Most often an artificial sealing is used, which is based on a soil liner from cohesive soils (clays, silts. Usability evaluation of bottom sediments from Rzeszowski Reservoir for building these liners was presented in the paper. Sediments from dam reservoirs, gathered as a result of the siltation process, can be a valuable material for earthworks purposes. Determination of their possible ways of usage is important, especially before the planned dredging, because thanks to that this material will not be put on a heap. Based on the analysis of the geotechnical parameters of these sediments it was stated that this material can be preliminary allowed for using in liners.

  15. Impulsive force of debris flow on a curved dam

    Institute of Scientific and Technical Information of China (English)

    Chjeng-Lun SHIEH; Chia-Hsien TING; Hung-Wen PAN

    2008-01-01

    Although Sabo dams are an efficient method for river and basin management,traditional Sabo dams have a great impact on ecology and landscape.Moreover,such dams are hit and often damaged by great impulsive force when they block the debris flow.Therefore,alternative shapes for Sabo dam deserve thorough investigation.In this investigation,a curved dam was designed by changing the upstream-dam-surface geometric shape to reduce the impulsive force of the debris flow,with enhanced stability and reduced concrete mass being the anticipated outcomes.In this study,the flume and laboratory facilities simulated the impulsive force of the debris flow to the Sabo dams.Three geometric forms,including vertical,slanted and curved Sabo dams,were used to determine the impulsive force.Impulsive force theories of the debris flow were derived from the momentum equation and the Bernoulli equation.In these,the impulsive force was balanced by the friction force of the Sabo dam and the opposite force of the load cell behind the dam as it was hit by the debris flow.Positive correlations were found when comparing the experimental data with the theoretical results.These findings suggest that our impulsive force theory has predictive validity with regard to the experimental data.The results from both theory and experimental data clearly show that curved dams were sustained less force than the other dams under the same debris flow.This comparison demonstrates the importance of curved geometry for a well-designed Sabo dam.

  16. Biomechanics of longitudinal arch support mechanisms in foot orthoses and their effect on plantar aponeurosis strain.

    Science.gov (United States)

    Kogler, G F; Solomonidis, S E; Paul, J P

    1996-07-01

    OBJECTIVE: The purpose of this investigation was to quantify the longitudinal arch support properties of several types of foot orthosis. DESIGN: An in vitro method that simulated 'static stance' was used to determine arch support capabilities, with plantar aponeurosis strain implemented as the performance measure. BACKGROUND: A longitudinal arch support mechanism of an orthosis resists depression of the foot's arches by transferring a portion of the load to the medial structures of the foot. Since the plantar aponeurosis is in tension when the foot is loaded, a quantifiable decrease in strain should occur with an adequate orthotic arch control mechanism. METHODS: A differential variable reluctance transducer was surgically implanted in the plantar aponeurosis of cadaveric donor limb feet (n = 7). Each specimen was mounted in an electromechanical test machine which applied a load of up to 900 N axially to the tibia. The test schedule was divided into seven test conditions: specimen barefoot; specimen with shoe and specimen with shoe and five different orthoses. RESULTS: The University of California Biomechanics Laboratory Shoe Insert and two other foot orthoses significantly decreased the strain in the plantar aponeurosis compared to the barefoot control and were considered effective arch supports (P plantar aponeurosis strain. Significant variations of time required to achieve the specified load levels were recorded among the test conditions, indicating the relative cushioning properties of the shoe/orthosis systems. CONCLUSIONS: The patterns of plantar aponeurosis strain observed in cadaveric tests suggest that certain types of orthoses are more effective than others in the support of the foot's longitudinal arches. It is suggested that to support the longitudinal arches of the foot effectively the medial surface contours of the orthosis must stabilize the apical bony structure of the foot's arch. RELEVANCE: Reducing tension in the plantar aponeurosis is an

  17. SAFETY PERFORMANCE ANALYSIS OF ROCK WEDGES UNDER LEFT SKEWBACK OF UPSTREAM DAM LINE IN BAIHETAN HYDROPOWER STATION%白鹤滩水电站上坝线左拱座楔形体安全性能分析

    Institute of Scientific and Technical Information of China (English)

    徐卫亚; 狄圣杰; 郑文棠; 吴关叶

    2011-01-01

    The rock wedges under left skewback of the upstream dam line are cut by many steep faults in the dam site of Baihetan Hydropower Station. They locate at the bottom and the downstream of the arch dam. Their stable movement or not will affect the safety of dam foundation and arch dam. The safety performance of arch dam and rock wedges are comprehensively analyzed considering the complicated crack hydraulic pressure in joint planes between rock wedges, various of water pressures are programmed and the approach is validated using the conceptual model in the software fast Lagrangian analysis of continua in 3 dimensions(FLAC3D). According to the results of calculation and the displacement of the selected typical nodes, the stability safety degree, surface safety factor and yield expansion of rock wedges are studied. Research shows that safety degree in sliding surface LS331 is lower than that in contact surface between the dam and the foundation, upstream dam heel of right bank begins to appear local yield when the overload safety coefficient is 1.5 with a consideration of many effects; the rock wedges cannot work normally when the overload safety coefficient is 3.1; the dam foundation can't work normally when the overload safety coefficient is 3.3; and the rock masses under dam foundation is overall destroyed when the overload safety coefficient is 5.5.%白鹤滩水电站上坝线左拱座底部岩体被陡倾断层切割成多个楔形体,坐落于拱坝底部及其下游,其稳定性直接影响到坝基和拱坝的安全.考虑楔形岩体各滑动面上复杂的渗透压力进行拱坝及楔形体安全性能分析,在FLAC3D中编制多种形式水压力施加程序,并以概念模型进行验证.根据数值计算结果,通过分析所选取结构面的典型节点位移变化,研究楔形体的稳定安全度、面安全系数及超载条件下屈服扩展状况,对其安全性能进行综合分析.研究表明:楔形体滑面考虑裂隙水压力

  18. Seismic performance evaluation of concrete gravity dams

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, Y.; Sasaki, T.; Kanenawa, K. [Public Works Research Institute, Tsukuba City (Japan); Hall, R.; Yule, D. [United States Army Engineer Research and Development Center, Vicksburg, MS (United States); Matheu, E. [Louisiana State Univ., Baton Rouge, LA (United States); Chudgar, A. [United States Army Corps of Engineers, Washington, DC (United States)

    2004-07-01

    This paper addresses technical issues related to seismic design practices and current evaluation methods in Japan and the United States. Nonlinear analysis procedures can identify the ultimate capacity of existing concrete dams, taking into account the most critical nonlinear phenomena controlling the response. A numerical model of a non-overflow monolith of Koyna Dam, subject to earthquake motion, is used as a case study to compare the different approaches for seismic evaluation of concrete gravity dams currently employed in the two countries. The complexity of nonlinear analysis procedures and the scarcity of appropriate calibration strategies force analysts to frequently interpret results using their own judgment. It was concluded that the influence of the input parameters and ground excitation on the nonlinear dynamic response should be investigated in order to identify the most critical conditions. It was also suggested that methodologies for qualitative damage estimation based on results from linear analyses could be used to develop a systematic assessment tool and reference framework for the adequate interpretation of results. 14 refs., 2 tabs., 13 figs.

  19. 大跨度连续下承式钢箱拱桥设计%Design of Long-Span Continuous Through Type Steel Box Arch Bridge

    Institute of Scientific and Technical Information of China (English)

    李国普; 李斐然

    2016-01-01

    为满足桥梁的景观和功能要求,小浪底坝后保护区交通桥上部结构采用(95+152+95) m三跨连续下承式钢箱拱结构。主梁为预应力混凝土π形梁,采用钢管桩+贝雷梁法施工。拱肋为钢箱提篮拱,结构用钢采用Q345D钢板,先工厂预制再现场焊接成型。吊索采用7根φ15.2环氧喷涂无粘结钢绞线,缠包后热挤HDPE ,抗拉强度标准值1860 M Pa。下部结构采用柱式台、倒V形实体薄壁墩、高桩承台、钻孔灌注桩基础。采用非线性程序TDV进行计算分析,结果表明,该桥的强度、刚度和稳定性以及抗震性能均满足规范要求。%To meet the landscape and function requirements proposed , the transportation bridge in the conservation area behind the Xiaolangdi Dam adopts a three‐span continuous through type steel box arch bridge structure with span arrangement of (95+152+95) m .The main girder is the prestressed concrete π‐shaped girder ,constructed by the combined use of steel tube piles and bailey truss .T he arch ribs are the steel box basket handle arches .T he predominant material used for the structure is the Q345D steel plate ,and all the components are prefabricated in the factory and transported to the bridge site for welding to take shape .Each hanger consists of 7φ15 .2 epoxy non‐binding steel strands ,extruded with HDPE after wrapping .The hanger has a standard tensile strength of 1 860 MPa .The substructure of the bridge incorporates column‐type abutments ,in‐versed V‐shaped solid thin‐wall piers ,high‐rise pile caps and bored piles .The non‐linear program TDV was used to do calculation .The results of the calculation demonstrate that the strength ,ri‐gidity ,reliability and anti‐seismic performance of the bridge all meet the code requirements .

  20. 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.

  1. 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

  2. Simulating dam-breach flood scenarios of the Tangjiashan landslide dam induced by the Wenchuan Earthquake

    Directory of Open Access Journals (Sweden)

    X. Fan

    2012-10-01

    Full Text Available Floods from failures of landslide dams can pose a hazard to people and property downstream, which have to be rapidly assessed and mitigated in order to reduce the potential risk. The Tangjiashan landslide dam induced by the Mw = 7.9 2008 Wenchuan earthquake had impounded the largest lake in the earthquake affected area with an estimated volume of 3 × 108 m3, and the potential catastrophic dam breach posed a serious threat to more than 2.5 million people in downstream towns and Mianyang city, located 85 km downstream. Chinese authorities had to evacuate parts of the city until the Tangjiashan landslide dam was artificially breached by a spillway, and the lake was drained. We propose an integrated approach to simulate the dam-breach floods for a number of possible scenarios, to evaluate the severity of the threat to Mianyang city. Firstly, the physically-based BREACH model was applied to predict the flood hydrographs at the dam location, which were calibrated with observational data of the flood resulting from the artificial breaching. The output hydrographs from this model were inputted into the 1-D–2-D SOBEK hydrodynamic model to simulate the spatial variations in flood parameters. The simulated flood hydrograph, peak discharge and peak arrival time at the downstream towns fit the observations. Thus this approach is capable of providing reliable predictions for the decision makers to determine the mitigation plans. The sensitivity analysis of the BREACH model input parameters reveals that the average grain size, the unit weight and porosity of the dam materials are the most sensitive parameters. The variability of the dam material properties causes a large uncertainty in the estimation of the peak flood discharge and peak arrival time, but has little influence on the flood inundation area and flood depth downstream. The effect of cascading breaches of smaller dams downstream of the Tangjiashan dam was

  3. Do Hydroelectric Dams Mitigate Global Warming? The Case of Brazil's Curuna Dam

    Energy Technology Data Exchange (ETDEWEB)

    Fearnside, P.M. [National Institute for Research in the Amazon (INPA), C.P. 478, 69011-970 Manaus, Amazonas (Brazil)

    2005-10-15

    Hydroelectric dams in tropical forest areas emit greenhouse gases, as illustrated by the Curuna dam in the Amazonian portion of Brazil. Emissions include carbon dioxide from decay of the above-water portions of trees that are left standing in the reservoir and methane from soft vegetation that decays under anaerobic conditions on the bottom of the reservoir, especially macrophytes (water weeds) and vegetation that grows in the drawdown zone and is flooded when the reservoir water level rises. Some methane is released from the reservoir surface through bubbling and diffusion, but larger amounts are released from water passing through the turbines and spillway. Methane concentration in the water increases with depth, and the turbines and spillway draw water from sufficient depth to have substantial methane content. In 1990 (13 years after filling), the Curuna Dam emitted 3.6 times more greenhouse gases than would have been emitted by generating the same amount of electricity from oil.

  4. Assessment model of dam operation risk based on monitoring data

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Although the dams produce remarkable social and economic benefits,the threat made by unsafe dams to the life and property of people who live in the lower river area is un-negligible.Based on the monitoring data which reflect the safety condition of dams,the risk degree concept is proposed and the analysis system and model for evaluating risk degree (rate) are established in this paper by combining the reliability theory and field monitoring data.The analysis method for risk degree is presented based on Bayesian approach.A five-grade risk degree system for dam operation risk and corresponding risk degree is put forward according to the safety condition of dams.The operation risks of four cascade dams on some river are analyzed by the model and approach presented here and the result is adopted by the owner.

  5. 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.

  6. Predicting surfacing internal erosion in moraine core dams

    OpenAIRE

    2010-01-01

    Dams that comprise broadly and widely graded glacial materials, such as moraines, have been found to be susceptible to internal erosion, perhaps more than dams of other soil types. Internal erosion washes out fine-grained particles from the filling material; the erosion occurs within the material itself or at an interface to another dam zone, depending on the mode of initiation. Whether or not internal erosion proceeds depend on the adequacy of the filter material. If internal erosion is allo...

  7. Stochastic Boundary Element Analysis of Concrete Gravity Dam

    Institute of Scientific and Technical Information of China (English)

    张明; 吴清高

    2002-01-01

    Stochastic boundary integral equations for analyzing large structures are obtained from the partial derivatives of basic random variables. A stochastic boundary element method based on the equations is developed to solve engineering problems of gravity dams using random factors including material parameters of the dam body and the foundation, the water level in the upper reaches, the anti-slide friction coefficient of the dam base, etc. A numerical example shows that the stochastic boundary element method presented in this paper to calculate the reliability index of large construction projects such as a large concrete gravity dam has the advantages of less input data and more precise computational results.

  8. Environmental impacts of increased hydroelectric development at existing dams

    Energy Technology Data Exchange (ETDEWEB)

    Railsback, S. F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Cada, G. F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Petrich, C. H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sale, M. J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shaakir-Ali, J. A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Watts, J. A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Webb, J. W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    1991-04-01

    This report describes the environmental impacts of a proposed U.S. Department of Energy (DOE) initiative to promote the development of hydropower resources at existing dams. Hydropower development at existing dams has, in general, fewer impacts than development of additional fossil-fueled resources or hydropower at new dams, although potential cumulative impacts of developing multiple hydropower projects have not been explicitly addressed. Environmental review of project impacts and mitigation needs can ensure that additional hydropower development at existing dams can provide a renewable resource with fewer impacts than alternative resources.

  9. 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...

  10. Role of the tranverse arch in stiffness of the human foot

    Science.gov (United States)

    Dias, Marcelo A.; Singh, Dhiraj K.; Bandi, Mahesh M.; Venkadesan, Madhusudhan; Mandre, Shreyas

    2015-03-01

    Human ancestors evolved from walking, around 6 million years (Ma) ago, to regular endurance running, around 2 Ma ago. Simultaneously, the feet evolved from a relatively flat structure like that of current day Chimpanzees (or our hands), to the modern human foot with two arches, a longitudinal and a transversal arch. The feet play a crucial role in locomotion by providing sufficient stiffness for propulsion, and being soft and pliable to absorb impacts and store energy elastically. Here we show that the transverse arch could play a central role in stiffness modulation. We first treat the foot as an elastic shell that is with intrinsic curvature. Calculations, numerics and physical experiments all show that for a foot-like shell, the stiffness has a power-law dependence on transverse curvature beyond a critical value. On the other hand, for purely longitudinally curved feet, or transverse curvature below the critical value, lead to low stiffness like a flat plate. Discrete realizations of a continuum shell, more closely resembling the human foot, also exhibit curvature induced stiffening. These results shed light on the role of the quintessentially human feature of a doubly arched foot, and suggest mechanical consequences of disorders such as a collapsed arch. HFSP RGY0091/2013.

  11. Endothelium in the pharyngeal arches 3, 4 and 6 is derived from the second heart field.

    Science.gov (United States)

    Wang, Xia; Chen, Dongying; Chen, Kelley; Jubran, Ali; Ramirez, AnnJosette; Astrof, Sophie

    2017-01-15

    Oxygenated blood from the heart is directed into the systemic circulation through the aortic arch arteries (AAAs). The AAAs arise by remodeling of three symmetrical pairs of pharyngeal arch arteries (PAAs), which connect the heart with the paired dorsal aortae at mid-gestation. Aberrant PAA formation results in defects frequently observed in patients with lethal congenital heart disease. How the PAAs form in mammals is not understood. The work presented in this manuscript shows that the second heart field (SHF) is the major source of progenitors giving rise to the endothelium of the pharyngeal arches 3 - 6, while the endothelium in the pharyngeal arches 1 and 2 is derived from a different source. During the formation of the PAAs 3 - 6, endothelial progenitors in the SHF extend cellular processes toward the pharyngeal endoderm, migrate from the SHF and assemble into a uniform vascular plexus. This plexus then undergoes remodeling, whereby plexus endothelial cells coalesce into a large PAA in each pharyngeal arch. Taken together, our studies establish a platform for investigating cellular and molecular mechanisms regulating PAA formation and alterations that lead to disease.

  12. 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.

  13. 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

  14. 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...

  15. 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.

  16. Dam operations affect route-specific passage and survival of juvenile Chinook salmon at a main-stem diversion dam

    Science.gov (United States)

    Perry, Russell W.; Kock, Tobias J.; Couter, Ian I; Garrison, Thomas M; Hubble, Joel D; Child, David B

    2016-01-01

    Diversion dams can negatively affect emigrating juvenile salmon populations because fish must pass through the impounded river created by the dam, negotiate a passage route at the dam and then emigrate through a riverine reach that has been affected by reduced river discharge. To quantify the effects of a main-stem diversion dam on juvenile Chinook salmon in the Yakima River, Washington, USA, we used radio telemetry to understand how dam operations and river discharge in the 18-km reach downstream of the dam affected route-specific passage and survival. We found evidence of direct mortality associated with dam passage and indirect mortality associated with migration through the reach below the dam. Survival of fish passing over a surface spill gate (the west gate) was positively related to river discharge, and survival was similar for fish released below the dam, suggesting that passage via this route caused little additional mortality. However, survival of fish that passed under a sub-surface spill gate (the east gate) was considerably lower than survival of fish released downstream of the dam, with the difference in survival decreasing as river discharge increased. The probability of fish passing the dam via three available routes was strongly influenced by dam operations, with passage through the juvenile fish bypass and the east gate increasing with discharge through those routes. By simulating daily passage and route-specific survival, we show that variation in total survival is driven by river discharge and moderated by the proportion of fish passing through low-survival or high-survival passage routes.

  17. Actualité du roman archéologique

    Directory of Open Access Journals (Sweden)

    Philippe Dufour

    2009-01-01

    Full Text Available Salammbô a beau se passer au IIIe siècle avant Jésus-Christ, Flaubert a beau y voir une ressource pour fuir le monde moderne, le roman antique n’en pense pas moins l’Histoire contemporaine, au moins par intermittence. On essaie de le montrer à propos d’un court fragment rescapé du chapitre explicatif, la description des assemblées des Syssites. Loin de démarquer simplement telle ou telle source (comme l’analyse aristotélicienne de la constitution carthaginoise dans La Politique, le paragraphe décrivant le banquet des Riches pendant que les Barbares entourent la ville évoque en surimpression la fête impériale sur fond de peur sociale. Des images relais (Les Romains de la décadence de Thomas Couture, Les Châtiments de Victor Hugo incitent le premier public à une lecture allégorique. Le chronotope de l’assemblée dénonce l’illusion d’un pouvoir et figure le devenir historique. Flaubert s’approprie ainsi de façon originale le genre du roman archéologique tel que l’abbé Barthélemy l’inventa ou tel que Henryk Sienkiewick le prolongera. S’y vérifie sa définition de l’histoire comme réflexion du présent sur le passé.Some scholars like Anne Green have shown that Flaubert in his historical novel, Salammbô, frequently alludes to contemporary history in spite of the obvious difference between the Carthaginian civilization and the modern world. In this essay I will try to grasp the shift in referenciality through a small description (a meeting between the wealthy, inspired by Aristotle’s Politics: Hugolian images of decadence from Les Châtiments appear superimposed on it, so that the archeological novel turns into an allegorical satire on the Second Empire.

  18. Monitoring health in African dams : the Kamburu dam (Kenya) as a test case

    NARCIS (Netherlands)

    J.M.V. Oomen

    1981-01-01

    textabstractDams are among the obvious efforts to improve the economic situation in a developing country. They aim at using locally available natural resources. At present they are among the most popular means for promoting socio-economic development. A significant number of these programmes have be

  19. Quasi-stable Slope-Failure Dams in High Asia

    Science.gov (United States)

    Shroder, J. F.

    2010-12-01

    Collapses of steep mountain slopes in the Himalaya, Karakoram, Pamir, Hindu Kush, and Tibetan Plateau are well known as a result of:(1) generally high seismicity in active tectonic areas; (2) prior deglaciation leaving undercut, unstable cliffs; (3) present-day debuttressing of rock cliffs by glacial down-wasting in conditions of global warming; and (4) degradation of permafrost cohesion and water-ice cementation in high mountain slopes. Landslide dams across mountain rivers are also well known worldwide and generally do not endure for long because of the common landslide-lake outburst floods (LLOF) whose discharge is commonly sufficiently large to remove much of the dam in a short time. A number of massive slope-failure dams in south High Asia, however, have endured for centuries and require explanations for the length of duration, whereas recent examples require robust assessment for better predictive hazard analysis. Three main factors contribute to longevity of slope-failure dams: (1) mega-rocks >15-30 m that inhibit dam failure in overflow breaches; (2) mega-porosity wherein incoming discharge to the landslide lake is balanced by subterranean water through-flow within the landslide dam; (3) impermeable clay fills caused by remobilization of prior lacustrine-dammed sediment that impart dam strength to allow lasting integrity for a time, and (4) climate-change induced lake-level lowering. Several examples of long-lived or unusually stable, slope-failure dams associated with pronounced structural/tectonic associations include: (1) Pangong Tso, Ladakh and Tibet; (2) Lake Shewa, Afghanistan; (3) Sarez Lake, Tajikistan; and (4) Lake Hunza, Pakistan. Pangong Tso and Lake Shewa were emplaced thousands of years ago and only Lake Shewa shows some instability of the dam front where percolating water maintains lake level but may be causing new slumping. Sarez Lake behind the Usoi landslide dam was emplaced by an earthquake in 1911 and maintains its level by seepage. Lake

  20. Advanced numerical simulation of collapsible earth dams

    Energy Technology Data Exchange (ETDEWEB)

    De Farias, M.M.; Cordao Neto, M.P. [Brasilia Univ., Federal District (Brazil). Dept. of Civil and Environmental Engineering

    2010-12-15

    This paper discussed a systematic methodology for the hydromechanical coupled numerical analysis of earth dams constructed with unsaturated collapsible soil. Every design stage was considered, including construction, reservoir filling, and advance of saturation front until the steady-state flow condition is attained. A transient analysis of safety factors applicable to 3-dimensional conditions was presented, giving consideration to unsaturated materials and the interrelation between hydraulic and mechanical phenomena by solving equilibrium and continuity conditions at the same time. The finite element method was used to formulate equilibrium and continuity conditions for both soil skeleton and pore water, which necessitated a realistic mechanical model for the stress-strain-suction relation in unsaturated porous material and adequate constitutive models related to water flow and storage, giving special consideration to imposing appropriate boundary conditions for each simulation stage. The methodology was applied to the analysis of earth dams composed of soils at optimum, dry of optimum, and mixed compaction conditions. The dry section simulated dams constructed using poorly compacted, dry material, which are prone to collapse. By strategically placing the optimum materials in the areas of the earth fill that are most stressed, the mixed section could be designed less expensively with the same or better performance as the homogenous section at optimum conditions. The coupled analysis provides a higher safety factor than uncoupled analysis and a realistic picture of end-of-construction pore pressure distribution. The simulation of reservoir filling and saturation front advance permitted clear identification of the initialization, development, and evolution of internal failure mechanisms. 21 refs., 6 tabs., 19 figs.

  1. Evaluation Model of Life Loss Due to Dam Failure

    Science.gov (United States)

    Huang, Dongjing

    2016-04-01

    Dam failure poses a serious threat to human life, however there is still lack of systematic research on life loss which due to dam failure in China. From the perspective of protecting human life, an evaluation model for life loss caused by dam failure is put forward. The model building gets three progressive steps. Twenty dam failure cases in China are preferably chosen as the basic data, considering geographical location and construction time of dams, as well as various conditions of dam failure. Then twelve impact factors of life loss are selected, including severity degree of flood, population at risk, understanding of dam failure, warning time, evacuation condition, number of damaged buildings, water temperature, reservoir storage, dam height, dam type, break time and distance from flood area to dam. And through principal component analysis, it gets four principal components consisting of the first flood character principle component, the second warning system principle component, the third human character principle component and the fourth space-time impact principle component. After multivariate nonlinear regression and ten-fold validation in combination, the evaluation model for life loss is finally established. And the result of the proposed model is closer to the true value and better in fitting effect in comparison with the results of RESCDAM method and M. Peng method. The proposed model is not only applied to evaluate life loss and its rate under various kinds of dam failure conditions in China, but also provides reliable cause analysis and prediction approach to reduce the risk of life loss.

  2. 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.

  3. Damage propagation in a masonry arch subjected to slow cyclic and dynamic loadings

    Directory of Open Access Journals (Sweden)

    J. Toti

    2014-07-01

    Full Text Available In the present work, the damage propagation of a masonry arch induced by slow cyclic and dynamic loadings is studied. A two-dimensional model of the arch is proposed. A nonlocal damage-plastic constitutive law is adopted to reproduce the hysteretic characteristics of the masonry material, subjected to cyclic static loadings or to harmonic dynamic excitations. In particular, the adopted cohesive model is able to take into account different softening laws in tension and in compression, plastic strains, stiffness recovery and loss due to crack closure and reopening. The latter effect is an unavoidable feature for realistically reproducing hysteretic cycles. In the studied case, an inverse procedure is used to calibrate the model parameters. Then, nonlinear static and dynamic responses of the masonry arch are described together with damage propagation paths.

  4. Common variable immunodeficiency syndrome with right aortic arch: a case report

    Directory of Open Access Journals (Sweden)

    Erbay Riza

    2004-02-01

    Full Text Available Abstract Background Common variable immunodificiency syndrome predominantly affects adults. It is characterized by low production of all the major classes of immunoglobulins. We report a case of common variable immunodeficiency syndrome with right aortic arch. An association of right-sided arch and common variable immunodificiency syndrome has not been previously reported. Case presentation A 41-year-old female patient presented with a history of recurrent pneumonia, sinusitis, otitis media, diarrhoea, cystitis since childhood. Biochemical and immunocytochemical analysis revealed common variable immunodeficiency syndrome and radiological evaluation confirmed right aortic arch and aberrant left subclavian artery. Conclusion Common variable immunodeficiency syndrome syndrome is a clinical entity that should be kept in mind in patients with recurrent infections of different sites.

  5. 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.

  6. 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...... terms of the likelihood function and is related to the recent so-called self-weighted QMLE in Ling (2007b). We show that the MQMLE is asymptotically normal irrespectively of the existence of finite moments, as geometric ergodicity alone suffice. Moreover, our included simulations show that the MQMLE...... for the QMLE to be asymptotically normal. Finally, geometric ergodicity for AR-ARCH processes is shown to hold under mild and classic conditions on the AR and ARCH processes....

  7. 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.)

  8. Thermal effects of dams in the Willamette River basin, Oregon

    Science.gov (United States)

    Rounds, Stewart A.

    2010-01-01

    Methods were developed to assess the effects of dams on streamflow and water temperature in the Willamette River and its major tributaries. These methods were used to estimate the flows and temperatures that would occur at 14 dam sites in the absence of upstream dams, and river models were applied to simulate downstream flows and temperatures under a no-dams scenario. The dams selected for this study include 13 dams built and operated by the U.S. Army Corps of Engineers (USACE) as part of the Willamette Project, and 1 dam on the Clackamas River owned and operated by Portland General Electric (PGE). Streamflows in the absence of upstream dams for 2001-02 were estimated for USACE sites on the basis of measured releases, changes in reservoir storage, a correction for evaporative losses, and an accounting of flow effects from upstream dams. For the PGE dam, no-project streamflows were derived from a previous modeling effort that was part of a dam-relicensing process. Without-dam streamflows were characterized by higher peak flows in winter and spring and much lower flows in late summer, as compared to with-dam measured flows. Without-dam water temperatures were estimated from measured temperatures upstream of the reservoirs (the USACE sites) or derived from no-project model results (the PGE site). When using upstream data to estimate without-dam temperatures at dam sites, a typical downstream warming rate based on historical data and downstream river models was applied over the distance from the measurement point to the dam site, but only for conditions when the temperature data indicated that warming might be expected. Regressions with measured temperatures from nearby or similar sites were used to extend the without-dam temperature estimates to the entire 2001-02 time period. Without-dam temperature estimates were characterized by a more natural seasonal pattern, with a maximum in July or August, in contrast to the measured patterns at many of the tall dam sites

  9. Comparative study of dental arch width in plaster models, photocopies and digitized images

    Directory of Open Access Journals (Sweden)

    Maria Cristina Rosseto

    2009-06-01

    Full Text Available The aim of this study was to comparatively assess dental arch width, in the canine and molar regions, by means of direct measurements from plaster models, photocopies and digitized images of the models. The sample consisted of 130 pairs of plaster models, photocopies and digitized images of the models of white patients (n = 65, both genders, with Class I and Class II Division 1 malocclusions, treated by standard Edgewise mechanics and extraction of the four first premolars. Maxillary and mandibular intercanine and intermolar widths were measured by a calibrated examiner, prior to and after orthodontic treatment, using the three modes of reproduction of the dental arches. Dispersion of the data relative to pre- and posttreatment intra-arch linear measurements (mm was represented as box plots. The three measuring methods were compared by one-way ANOVA for repeated measurements (α = 0.05. Initial / final mean values varied as follows: 33.94 to 34.29 mm / 34.49 to 34.66 mm (maxillary intercanine width; 26.23 to 26.26 mm / 26.77 to 26.84 mm (mandibular intercanine width; 49.55 to 49.66 mm / 47.28 to 47.45 mm (maxillary intermolar width and 43.28 to 43.41 mm / 40.29 to 40.46 mm (mandibular intermolar width. There were no statistically significant differences between mean dental arch widths estimated by the three studied methods, prior to and after orthodontic treatment. It may be concluded that photocopies and digitized images of the plaster models provided reliable reproductions of the dental arches for obtaining transversal intra-arch measurements.

  10. 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.

  11. 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.

  12. Dynamic decision making for dam-break emergency management – Part 2: Application to Tangjiashan landslide dam failure

    Directory of Open Access Journals (Sweden)

    M. Peng

    2013-02-01

    Full Text Available Tangjiashan landslide dam, which was triggered by the Ms = 8.0 Wenchuan earthquake in 2008 in China, threatened 1.2 million people downstream of the dam. All people in Beichuan Town 3.5 km downstream of the dam and 197 thousand people in Mianyang City 85 km downstream of the dam were evacuated 10 days before the breaching of the dam. Making such an important decision under uncertainty was difficult. This paper applied a dynamic decision-making framework for dam-break emergency management (DYDEM to help rational decision in the emergency management of the Tangjiashan landslide dam. Three stages are identified with different levels of hydrological, geological and social-economic information along the timeline of the landslide dam failure event. The probability of dam failure is taken as a time series. The dam breaching parameters are predicted with a set of empirical models in stage 1 when no soil property information is known, and a physical model in stages 2 and 3 when knowledge of soil properties has been obtained. The flood routing downstream of the dam in these three stages is analyzed to evaluate the population at risk (PAR. The flood consequences, including evacuation costs, flood damage and monetized loss of life, are evaluated as functions of warning time using a human risk analysis model based on Bayesian networks. Finally, dynamic decision analysis is conducted to find the optimal time to evacuate the population at risk with minimum total loss in each of these three stages.

  13. 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.

  14. 33 CFR 117.705 - Beaver Dam Creek.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Beaver Dam Creek. 117.705 Section 117.705 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.705 Beaver Dam Creek. The draw of...

  15. Institutionalizing the option of dam removal: the New Hampshire initiative.

    Science.gov (United States)

    Lindloff, S D

    2003-01-01

    For two years, the State of New Hampshire has worked to institutionalize the option of dam removal. The high gradient streams that flow through the granite hills and mountains of this small northeastern state provided ideal conditions for dam construction, particularly during America's Industrial Revolution of the 1800s when mills were constructed throughout the area. With more than 4,800 dams in the state's database, there are many opportunities for the removal of dams that no longer serve a useful purpose, have become a public safety hazard and impact the river environment. Efforts to facilitate removal of dams in New Hampshire include the formation of a River Restoration Task Force and the creation of a dam removal program within the state agency responsible for regulating dams. This has led to the removal of two dams in the past year, with approximately ten additional projects in various stages of planning. A history of this agency-led initiative, as well as a discussion of the program's strengths, challenges and goals for the future are presented.

  16. Geophysical methods for the assessment of earthen dams

    Science.gov (United States)

    Dams and levees are an integral part of the fluvial system in watersheds. Their stability is of utmost concern to the Nation and to those directly impacted should failure occur. There are some 88,000 dams and 110,000 miles of levees in the USA. Many of those are earthen embankments and structures su...

  17. Measures of struggle against appearance of cracks in earth dams

    Directory of Open Access Journals (Sweden)

    Ibraeva Yulia

    2016-01-01

    Full Text Available The article describes a method calculation of the basic parameters of the transverse rows of pile of simple printed or precast dam. As well, in this article have been shown all the necessary formulas for this calculation and have been proposed solutions to prevent cracking in the dams.

  18. Will the Three Gorges Dam Stand The Test of Time?

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    @@ Netizens have collected several ar-ticles about the flood-control capacity of the Three Gorges Dam. In these articles, its capacity was differently described as tackling flooding "once-in-10,000-years" "once-in- l,O00-years" or "once-in-a-century" Can you give the specifics of the flood control capacity of the dam?

  19. Major Dams of the United States - Direct Download

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This map layer portrays major dams of the United States, including Puerto Rico and the U.S. Virgin Islands. The map layer was created by extracting dams 50 feet or...

  20. Research advance in safety analysis methods for high concrete dam

    Institute of Scientific and Technical Information of China (English)

    REN; QingWen; XU; LanYu; WAN; YunHui

    2007-01-01

    High tensile stresses occurred in high concrete dams and in their foundation lead to the growing importance of their safety with the increase of concrete dam height.Without any exiting specification or successful experiences of concrete dams up to 300 m at home and abroad for reference,experts feel obliged to figure out how to perform safety analysis on high concrete dam.This paper involves the main contents and mechanical features of the safety analysis on high concrete dam and shows the current state and progress of the analysis methods.For the insufficiency and problems existing in normative methods,study on modern numerical method such as finite element method must be strengthened to find out the stress control criterion which is in accordance with the methods.Two aspects of the safety analysis of high dam--local damage from material level and integral destruction from structure level--should be considered.For the local damage,we should consider the non-homogeneity of material and strengthen the research of meso-damage mechanics.While for integral destruction of the system of high dam and its foundation,a study on non-strength theory should receive enough concerns.Further,attention should be paid to the research on the failure modes and criterions of high concrete dam failure analysis and safety evaluation,and the effect of uncertainty and classification of safety should be considered too.

  1. 78 FR 7810 - Glen Canyon Dam Adaptive Management Work Group

    Science.gov (United States)

    2013-02-04

    ... Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of public meeting. SUMMARY: The Glen Canyon Dam Adaptive Management Work Group.... L. 102-575) of 1992. The AMP includes a Federal advisory committee, the AMWG, a technical work...

  2. 75 FR 34476 - Glen Canyon Dam Adaptive Management Work Group

    Science.gov (United States)

    2010-06-17

    ... Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY: Bureau of Reclamation... Interior (Secretary) is renewing the charter for the Glen Canyon Dam Adaptive Management Work Group. The purpose of the Adaptive Management Work Group is to advise and to provide recommendations to the...

  3. 78 FR 21415 - Glen Canyon Dam Adaptive Management Work Group

    Science.gov (United States)

    2013-04-10

    ... Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of public meeting. SUMMARY: The Glen Canyon Dam Adaptive Management Work Group..., the AMWG, a technical work group, a Grand Canyon Monitoring and Research Center, and...

  4. 77 FR 43117 - Glen Canyon Dam Adaptive Management Work Group

    Science.gov (United States)

    2012-07-23

    ... Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of public meeting. SUMMARY: The Glen Canyon Dam Adaptive Management Work Group... Federal advisory committee, the AMWG, a technical work group (TWG), a Grand Canyon Monitoring and...

  5. 77 FR 9265 - Glen Canyon Dam Adaptive Management Work Group

    Science.gov (United States)

    2012-02-16

    ... Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of public meeting. SUMMARY: The Glen Canyon Dam Adaptive Management Work Group... Federal advisory committee, the AMWG, a technical work group (TWG), a Grand Canyon Monitoring and...

  6. Numerical analysis of a circular arch buckling under the symmetric pressure

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available The many interesting phenomena, such as snap-through, nonuniqueness, and stability, of a circular arch subjected to the symmetric pressure are studied. The balance of forces of an elemental length leads to a governing equation which is used to investigate stable states of the arch. With specific opening angle 2a=π/3 , the sensitivities of angle and curvature at a base are surveyed for various of spring constants. The variations of angle and curvature at an edge are almost the same if the spring constant τ≥10 .

  7. CALCUL PAR ELEMENT FINI MIXTE DE LA FORME OPTIMALE DE L’ARCHE

    Directory of Open Access Journals (Sweden)

    A AYADI

    2000-06-01

    Full Text Available L’objectif de ce travail est d’optimiser des fonctionnelles liées à la forme de l’Arche et soumises à des contraintes. La méthode des éléments finis mixtes est très avantageuses pour ce type de problème en mécanique des structures. L’Arche se comporte d’une manière régulière par rapport à la forme ce qui conduit à la mise en œuvre de l’algorithme du gradient projeté.

  8. Normalized least-squares estimation in time-varying ARCH models

    OpenAIRE

    Fryzlewicz, Piotr; Sapatinas, Theofanis; Subba Rao, Suhasini

    2008-01-01

    We investigate the time-varying ARCH (tvARCH) process. It is shown that it can be used to describe the slow decay of the sample autocorrelations of the squared returns often observed in financial time series, which warrants the further study of parameter estimation methods for the model. ¶ Since the parameters are changing over time, a successful estimator needs to perform well for small samples. We propose a kernel normalized-least-squares (kernel-NLS) estimator which has a closed form...

  9. Asymptotic normality of the QMLE in the level-effect ARCH model

    DEFF Research Database (Denmark)

    Dahl, Christian Møller; Iglesias, Emma M.

    In this paper consistency and asymptotic normality of the quasi maximum like-lihood estimator in the level-effect ARCH model of Chan, Karolyi, Longstaff and Sanders (1992) is established. We consider explicitly the case where the parameters of the conditional heteroskedastic process...... are in the stationary region and discuss carefully how the results can be extended to the region where the conditional heteroskedastic process is nonstationary. The results illustrate that Jensen and Rahbek's (2004a,2004b) approach can be extended further than to traditional ARCH and GARCH models....

  10. Right aortic arch with aberrant left innominate artery: MR imaging findings

    Energy Technology Data Exchange (ETDEWEB)

    Midiri, M. [Istituto di Radiologia, Policlinico Universitario, Bari (Italy); Finazzo, M.; Lagalla, R.; De Maria, M. [Istituto di Radiologia ``Pietro Cignolini``, Policlinico Universitario, Palermo (Italy); Pilato, M. [Reparto di Cardiochirurgia, Palermo (Italy)

    1999-03-01

    A rare case of a 60-year-old man with a right aortic arch and aberrant left innominate artery is presented. This case had an unusual clinical presentation. The dysphagia appeared suddenly in adulthood, whereas vascular rings, when symptomatic, usually manifest early in childhood.To our knowledge, MR imaging findings of this anomaly have never been reported. The diagnosis was made by MR imaging and confirmed by surgery. Magnetic resonance imaging can replace angiography in the assessment of the aortic arch anomalies. (orig.) With 4 figs., 11 refs.

  11. 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

  12. Cardiogenic shock due to coronary artery disease associated with interrupted aortic arch

    Directory of Open Access Journals (Sweden)

    Luís Alberto Oliveira Dallan

    2013-06-01

    Full Text Available Acute pulmonary edema is a serious event. Its occurrence in association with interrupted aortic arch and coronary heart disease is rare. Recently, an old patient developed cardiogenic shock and acute pulmonary edema due to acute coronary insufficiency, associated with interrupted aortic arch. The coronary angiography revealed occlusion of the right coronary artery and 95% obstruction in the left main coronary artery, associated with interruption of the descending aorta. Coronary artery bypass graft was performed, without extracorporeal circulation, to the anterior descending coronary artery. We discuss the initial management, given the seriousness of the case.

  13. Classification of the height and flexibility of the medial longitudinal arch of the foot

    Science.gov (United States)

    2012-01-01

    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 study are important for

  14. 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.

  15. 拱坝变形监测预报的随机森林模型及应用%Random forest model and application of arch dam′s deformation monitoring and prediction

    Institute of Scientific and Technical Information of China (English)

    罗浩; 郭盛勇; 包为民

    2016-01-01

    大坝变形预报对大坝运行安全评估起着至关重要的作用。传统模型预报精度不够、模拟效果不稳定;若大坝变形数据有异常值时,传统机器算法模型识别和处理异常值的灵活性很小,导致预报结果有偏差。为了解决这些问题,首次将随机森林算法运用到大坝变形监测领域,将大坝测点根据随机森林相似性矩阵分成若干个子集,针对每一个子集建立随机森林预测模型,分区建立预测模型更符合工程实际情况。选取拱坝变形作为研究对象,验证所建模型的适用性。结果表明,根据随机森林的相似性矩阵对大坝各测点的分区情况符合物理和工程实际意义,对各分区子集测点利用随机森林模型建立的预测模型,与支持向量机、BP神经网络模型相比,预测结果精度较高、模型稳定性好,为大坝变形监测提供了新思路。%Dam deformation prediction plays an important role in the safety assessment of dam operation .Traditional models lack forecasting precision and the simulation effect is not stable enough .Besides ,if abnormal values of dam deformation exist ,tradi‐tional machine algorithm model lacks the flexibility of dealing with these abnormal data ,which will lead to the deviation of the forecasting results .In order to solve these problems ,random forest algorithm was introduced to the field of dam deformation monitoring for the first time .Similarity matrix of random forest was applied to divide dam deformation monitoring points into several parts .Random forests prediction model was established for each part ,which will avoid the defects of traditional models such as modeling of single point or using the same model for all deformation monitoring points .Establishing forecasting model for different parts of dam was more in line with engineering practice .Deformation data of one arch dam was analyzed and the feasibility of random forest model was

  16. Management of dam safety at BC Hydro: the database tool

    Energy Technology Data Exchange (ETDEWEB)

    Oswell, Terry [BC Hydrom Burnaby, (Canada)

    2010-07-01

    BC Hydro has a wide range of dams, which raises a wide range of issues at many unique sites. A dam safety database was developed in 2000 to deal with the complexity and volume of information provided by deficiency investigations and surveillances. The database contains all documented deficiencies and non-conformances identified in the past 10 years. It records the risk ratings assigned to each issue. This paper described the implementation of the database tool, from the characterization of a dam safety issue to the use of the database itself. The dam safety database is now a key tool in managing the dam safety program at BC Hydro and has been useful for the last 10 years or so in prioritizing the program of deficiency investigations and capital projects. The development of a process to rate non-conformances is currently under study and will be implemented soon to aid in more efficient prioritization of maintenance activities.

  17. Modeling Experiment of Break of Debris-Flow Dam

    Institute of Scientific and Technical Information of China (English)

    CHENG Zunlan; GENG Xueyong; DANG Chao; LIU Jingjing

    2007-01-01

    Glaciers are extensively developed in the southwest of Tibet and the moraines are widely distributed with large depth. Large-scale debris flows are often reported which blocked rivers and formed dams. In this paper, seven large debris flows in four valleys are discussed, among which five dams developed. 13 sets of experiments have been conducted in laboratory to simulate the formation and failure of the dam. Finally, a model of dam failure is proposed and a formula is established to calculate the flood discharge:Q = kbhhk/T (B)/LG0.41, where bk is the outlet width of the dam atthe original water level, ht the erosive depth, T the time fromoverflow to final state of failure, the average width of lake; L thelength of the lake, and G the total potential energy of the water inthe lake.

  18. Sediment settling in the Latian Dam in Iran

    Institute of Scientific and Technical Information of China (English)

    Farhang BEHRANGI; Mohammad Ali BANIHASHEMI; Shayesteh MAHANI; Mohammad Reza RAHMANIAN

    2014-01-01

    Among the difficulties that influence future dam operations, reservoir sedimentation is the most problematic for engineers. This study predicted the amount and pattern of sedimentation for use in estimation of the useful lifespan of reservoirs and identification of optimal locations for outlets and intakes at the initial stages of dam design. Hydrographic surveys of different dams can provide better insight into this phenomenon. Latian Dam in Iran has conducted hydrographic surveys during 7 time periods. The amount and process of sedimentation in this reservoir were determined, and predictions of distribution of sediments were validated by well-known, common methods. The formation of a delta in the reservoir was investigated for different time periods after operation. Future problems due to the impacts of sedimentation on dam operation and the useful lifespan of the reservoir were predicted. In addition, the study results may be used for developing empirical methods to predict sedimentation patterns in other reservoirs.

  19. 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

  20. 78 FR 52973 - ICG Knott County, LLC, a Subsidiary of ICG, Inc., a Subsidiary of Arch Coal, Inc.; Including On...

    Science.gov (United States)

    2013-08-27

    ... Employment and Training Administration ICG Knott County, LLC, a Subsidiary of ICG, Inc., a Subsidiary of Arch... Regarding Application for Reconsideration for the workers and former workers of ICG Knott County, LLC, a... group eligibility of ICG Knott County, LLC, a subsidiary of ICG, Inc., a subsidiary of Arch Coal,...

  1. The artificial somato-autonomic reflex arch does not improve bowel function in subjects with spinal cord injury

    DEFF Research Database (Denmark)

    Rasmussen, Mikkel Mylius; Krogh, Klaus; Clemmensen, Dorte;

    2015-01-01

    Study design: Prospective cohort study. Objective: Although introduced for neurogenic bladder dysfunction, it has been suggested that the artificial somato-autonomic reflex arch alleviates neurogenic bowel dysfunction (NBD). We aimed at evaluating the effects of the reflex arch on NBD. Setting...

  2. 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

    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-arch ...

  3. Biomechanical consequences of plantar fascial release or rupture during gait: part I--disruptions in longitudinal arch conformation.

    Science.gov (United States)

    Sharkey, N A; Ferris, L; Donahue, S W

    1998-12-01

    To examine whether conformational changes induced by plantar fascial division may progress during gait, we loaded the feet of seven cadavers using an apparatus that simulates the actions of the extrinsic plantarflexors. We measured the effects of plantar fasciotomy at two instants in the terminal-stance phase of gait. Radiographic measurements of height of the arch, base length of the arch, and talo first-metatarsal angle were used to assess contributions to arch support made by the plantar fascia, tibialis posterior, peroneus longus and brevis, and digital flexor muscles. Complete fasciotomy caused significant collapse of the arch in the sagittal plane. Early in terminal stance, at the instant after heel-off, mean height of the arch decreased from 47 to 45 mm. Late in terminal stance, at the instant preceding contralateral heel strike, mean height of the arch decreased from 46 to 43. Effects of division of the central band, though significant, were mild. Medial base length of the arch increased from 163 to 167 mm in the absence of tibialis posterior contraction at late terminal stance. Arch-supporting abilities of the other extrinsic muscles were insignificant.

  4. Reference points suitable for evaluation of the additional arch length required for leveling the curve of Spee

    Science.gov (United States)

    Cho, Yong-Hwa; Gang, Sung-Nam

    2016-01-01

    Objective The additional arch length required for leveling (AALL) the curve of Spee (COS) can be estimated by subtracting the two-dimensional (2D) arch circumference, which is the projection of the three-dimensional (3D) arch circumference onto the occlusal plane, from the 3D arch circumference, which represents the arch length after leveling the COS. The purpose of this study was to determine whether the cusp tips or proximal maximum convexities are more appropriate reference points for estimating the AALL. Methods Sixteen model setups of the mandibular arch with COS depths ranging from 0 mm to 4.7 mm were constructed using digital simulation. Arch circumferences in 2D and 3D were measured from the cusp tips and proximal maximum convexities and used to calculate the AALL. The values obtained using the two reference points were compared with the paired t-test. Results Although the 3D arch circumference should be constant regardless of the COS depth, it decreased by 3.8 mm in cusp tip measurements and by 0.4 mm in proximal maximum convexity measurements as the COS deepened to 4.7 mm. AALL values calculated using the cusp tips as reference points were significantly smaller than those calculated using the proximal maximum convexities (p = 0.002). Conclusions The AALL is underestimated when the cusp tips are used as measurement reference points; the AALL can be measured more accurately using the proximal maximum convexities. PMID:27896209

  5. 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…

  6. Dam Inventory - DAMS_1996_EPA_IN: Inventory of Dams in Indiana, Derived from EPA BASINS (United States Environmental Protection Agency, Point Shapefile)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — DAMS_1996_EPA_IN is a point shapefile developed by the USEPA BASINS 3.0 program and clipped by Bernardin, Lochmueller and Associates. Clips were performed using the...

  7. Check dam and polyacrylamide performance under simulated stormwater runoff.

    Science.gov (United States)

    Kang, Jihoon; McCaleb, Melanie M; McLaughlin, Richard A

    2013-11-15

    High levels of turbidity and fine suspended sediments are often found in stormwater discharges from construction sites even when best management practices (BMPs) for sediment control are in place. This study evaluated turbidity reduction by three check dam types: 1) rock check dam representing a standard BMP, 2) excelsior wattle representing a fiber check dam (FCD), and 3) rock check dam wrapped with excelsior erosion control blanket (rock + excelsior ECB) representing an alternative FCD. Three check dams (all same type) were installed in a lined, 24-m ditch on a 5-7% slope and three consecutive simulated stormwater flows were run in the ditch. Additional tests were performed by adding granular polyacrylamide (PAM) on the check dams in the same manner using two sediment sources differing in clay content. Without PAM treatment, significantly higher effluent turbidity (>900 nephelometric turbidity units (NTU)) exited the ditch with rock check dams than with excelsior wattles or rock + excelsior ECBs (dam types was in the order of excelsior wattle > rock + excelsior ECB > rock check dam, indicating better water pooling behind the wattle. The PAM treatment reduced turbidity substantially (>75% relative to no PAM treatment) for all check dam types and it was very effective in excelsior wattles (<57 NTU) and rock + excelsior ECBs (<90 NTU) even during the third storm event. This study demonstrates that the passive treatment of runoff with PAM on FCDs (or rock + excelsior ECB) in construction site ditches can be very effective for sediment retention and turbidity reduction.

  8. Geophysical Investigations at Hidden Dam, Raymond, California Flow Simulations

    Science.gov (United States)

    Minsley, Burke J.; Ikard, Scott

    2010-01-01

    Numerical flow modeling and analysis of observation-well data at Hidden Dam are carried out to supplement recent geophysical field investigations at the site (Minsley and others, 2010). This work also is complementary to earlier seepage-related studies at Hidden Dam documented by Cedergren (1980a, b). Known seepage areas on the northwest right abutment area of the downstream side of the dam was documented by Cedergren (1980a, b). Subsequent to the 1980 seepage study, a drainage blanket with a sub-drain system was installed to mitigate downstream seepage. Flow net analysis provided by Cedergren (1980a, b) suggests that the primary seepage mechanism involves flow through the dam foundation due to normal reservoir pool elevations, which results in upflow that intersects the ground surface in several areas on the downstream side of the dam. In addition to the reservoir pool elevations and downstream surface topography, flow is also controlled by the existing foundation geology as well as the presence or absence of a horizontal drain in the downstream portion of the dam. The current modeling study is aimed at quantifying how variability in dam and foundation hydrologic properties influences seepage as a function of reservoir stage. Flow modeling is implemented using the COMSOL Multiphysics software package, which solves the partially saturated flow equations in a two-dimensional (2D) cross-section of Hidden Dam that also incorporates true downstream topography. Use of the COMSOL software package provides a more quantitative approach than the flow net analysis by Cedergren (1980a, b), and allows for rapid evaluation of the influence of various parameters such as reservoir level, dam structure and geometry, and hydrogeologic properties of the dam and foundation materials. Historical observation-well data are used to help validate the flow simulations by comparing observed and predicted water levels for a range of reservoir elevations. The flow models are guided by, and

  9. Channel evolution on the dammed Elwha River, Washington, USA

    Science.gov (United States)

    Draut, A.E.; Logan, J.B.; Mastin, M.C.

    2011-01-01

    Like many rivers in the western U.S., the Elwha River, Washington, has changed substantially over the past century in response to natural and human forcing. The lower river is affected by two upstream dams that are slated for removal as part of a major river restoration effort. In preparation for studying the effects of dam removal, we present a comprehensive field and aerial photographic analysis of dam influence on an anabranching, gravel-bed river. Over the past century with the dams in place, loss of the upstream sediment supply has caused spatial variations in the sedimentary and geomorphic character of the lower Elwha River channel. Bed sediment is armored and better sorted than on the naturally evolving bed upstream of the dams. On time scales of flood seasons, the channel immediately below the lower dam is fairly stable, but progresses toward greater mobility downstream such that the lowermost portion of the river responded to a recent 40-year flood with bank erosion and bed-elevation changes on a scale approaching that of the natural channel above the dams. In general, channel mobility in the lowest 4 km of the Elwha River has not decreased substantially with time. Enough fine sediment remains in the floodplain that – given sufficient flood forcing – the channel position, sinuosity, and braiding index change substantially. The processes by which this river accesses new fine sediment below the dams (rapid migration into noncohesive banks and avulsion of new channels) allow it to compensate for loss of upstream sediment supply more readily than would a dammed river with cohesive banks or a more limited supply of alluvium. The planned dam removal will provide a valuable opportunity to evaluate channel response to the future restoration of natural upstream sediment supply.

  10. 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.

  11. The Political Ecology of Chinese Large Dams in Cambodia: Implications, Challenges and Lessons Learnt from the Kamchay Dam

    Directory of Open Access Journals (Sweden)

    Giuseppina Siciliano

    2016-09-01

    Full Text Available Given the opportunities offered by foreign investment in energy infrastructure mostly by Chinese firms, the Government of Cambodia is giving high priority to developing hydropower resources for reducing energy poverty and powering economic growth. Using a “Political ecology of the Asian drivers” framework, this paper assesses China’s involvement in the development of large dams’ in Cambodia and its impacts on the access of natural resources such as water and energy by dam builders, local communities and the government. This analysis is based on 61 interviews and 10 focus group discussions with affected communities, institutional actors, Chinese dam builders and financiers in relation to the first large Chinese dam built in Cambodia: the Kamchay dam. Based on the results of the analysis this paper makes recommendations on how to improve the planning, implementation and governance of future large dams in Cambodia.

  12. Stability of earth dam with a vertical core

    Directory of Open Access Journals (Sweden)

    Orekhov Vyacheslav Valentinovich

    2016-01-01

    Full Text Available Earth dam with impervious element in the form of asphaltic concrete core is currently the most promising type of earth dams (due to simple construction technology and universal service properties of asphaltic concrete and is widely used in the world. However, experience in the construction and operation of high dams (above 160 m is not available, and their work is scarcely explored. In this regard, the paper discusses the results of computational prediction of the stress-strain state and stability of a high earth dam (256 m high with the core. The authors considered asphaltic concrete containing 7 % of bitumen as the material of the core. Gravel was considered as the material of resistant prisms. Design characteristics of the rolled asphaltic concrete and gravel were obtained from the processing of the results of triaxial tests. The calculations were performed using finite element method in elastoplastic formulation and basing on the phased construction of the dam and reservoir filling. The research shows, that the work of embankment dam with vertical core during filling of the reservoir is characterized by horizontal displacement of the lower resistant prism in the tailrace and the formation of a hard wedge prism descending along the core in the upper resistant prism. The key issue of the safety assessment is to determine the safety factor of the overall stability of the dam, for calculation of which the destruction of the earth dam is necessary, which can be done by reducing the strength properties of the dam materials. As a results of the calculations, the destruction of the dam occurs with a decrease in the strength characteristics of the materials of the dam by 2.5 times. The dam stability depends on the stability of the lower resistant prism. The destruction of its slope occurs on the classical circular-cylindrical surface. The presence of a potential collapse surface in the upper resistant prism (on the edges of the descending wedge does

  13. Estimating Snow Budget of Karaj Dam Reservoir

    Directory of Open Access Journals (Sweden)

    Manijeh G. Tali

    2009-01-01

    Full Text Available Problem statement: Most of the cold period precipitation of Karaj Basin falls in the form of snow. This snow and its run off are important to the dam and the local needs such as agriculture and the drinking water of Tehran. But due to the scarcity and in some elevations the lack of weather stations, measuring this snow cover and its run off is difficult. We have decided to estimate the amount of this snow cover by using surrogate methods such as satellite images of MODIS and temperature thresholds. Approach: To estimate the snow water budget of the Karaj Dam Reservoir Basin, first a temperature threshold of 3° Celsius was defined according to the analysis of daily temperature and precipitation values of Nesa station during 1960-2000. The elevation of this temperature was as low as 1590 m in February and 5734 m in August. During each month the melting snow was computed over the area between 3 and zero degrees Celsius and precipitation below zero degrees was considered as permanent snow cover. The precipitation of areas above 3° was computed as rain. Using this temperature threshold and the DEM map of the basin we estimated the snow cover and snow melt water of the basin. The snow cover area on the MODIS images was estimated and compared with that computed from temperature threshold. Both methods gave relatively similar results. At the end the snow melt water of the whole cold period was calculated and added up to estimate the total snow water budget. Results: The results showed that during the study months most (67.7% of the precipitation comes in the form of snow. And most of this snow (97.5% melts during months March and onward. Its monthly distributions are 3.8% in March, 22.7% in April and 71% in May. The total snow water entering the dam was about 181.73 million cubic meters. Conclusion: The comparison of the results from temperature thresholds with the MODIS images snow cover showed very little and negligible discrepancy. Therefore, this

  14. Fosfortab fra det dyrkede areal til Stevning Dam, Hindemaj og Haderslev Dam

    DEFF Research Database (Denmark)

    Andersen, Hans Estrup; Heckrath, Goswin; Thodsen, Hans;

    Størrelsen af dyrkningsbidraget til søerne i Haderslev Dam-systemet er vurderet med to forskellige metoder til at udgøre ca. 42 % af den samlede tilførsel. En risikokortlægning med det nye, danske P-indeks viser, at i alt 15 % af det dyrkede areal er i højrisiko mht. fosfortab. P-indeks-kortlægni......Størrelsen af dyrkningsbidraget til søerne i Haderslev Dam-systemet er vurderet med to forskellige metoder til at udgøre ca. 42 % af den samlede tilførsel. En risikokortlægning med det nye, danske P-indeks viser, at i alt 15 % af det dyrkede areal er i højrisiko mht. fosfortab. P...

  15. Overhead spine arch analysis of dairy cows from three-dimensional video

    Science.gov (United States)

    Abdul Jabbar, K.; Hansen, M. F.; Smith, M. L.; Smith, L. N.

    2017-02-01

    We present a spine arch analysis method in dairy cows using overhead 3D video data. This method is aimed for early stage lameness detection. That is important in order to allow early treatment; and thus, reduce the animal suffering and minimize the high forecasted financial losses, caused by lameness. Our physical data collection setup is non-intrusive, covert and designed to allow full automation; therefore, it could be implemented on a large scale or daily basis with high accuracy. We track the animal's spine using shape index and curvedness measure from the 3D surface as she walks freely under the 3D camera. Our spinal analysis focuses on the thoracic vertebrae region, where we found most of the arching caused by lameness. A cubic polynomial is fitted to analyze the arch and estimate the locomotion soundness. We have found more accurate results by eliminating the regular neck/head movements' effect from the arch. Using 22-cow data set, we are able to achieve an early stage lameness detection accuracy of 95.4%.

  16. 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.

  17. 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.

  18. Supravalvular aortic stenosis in adult with anomalies of aortic arch vessels and aortic regurgitation

    Science.gov (United States)

    Valente, Acrisio Sales; Alencar, Polyanna; Santos, Alana Neiva; Lobo, Roberto Augusto de Mesquita; de Mesquita, Fernando Antônio; Guimarães, Aloyra Guedis

    2013-01-01

    The supravalvular aortic stenosis is a rare congenital heart defect being very uncommon in adults. We present a case of supravalvular aortic stenosis in adult associated with anomalies of the aortic arch vessels and aortic regurgitation, which was submitted to aortic valve replacement and arterioplasty of the ascending aorta with a good postoperative course. PMID:24598962

  19. 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

  20. 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.