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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. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-01-15

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2011-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    DU Tingna; YE Rongbo; ZHAO Haifeng

    2012-01-01

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

  14. Influence of spatial variations in ground motion on earthquake response of arch dams

    Energy Technology Data Exchange (ETDEWEB)

    Chopra, A. [California Univ., Berkeley, CA (United States). Dept. of Civil and Environmental Engineering; Wang, J. [Tsinghua Univ., Beijing (China). Dept. of Hydraulic Engineering

    2010-07-01

    Ground motion recorded at arch dams demonstrate spatial variation or non-uniformity along the dam-foundation interface. Records obtained at two dams demonstrated this phenomena, notably the Pacoima Dam located in California during the magnitude 4.3 earthquake on January 13, 2001, and the magnitude 6.9 Northridge earthquake on January 17, 1994; and the Mauvoisin Dam located in Switzerland during the magnitude 4.6 Valpelline earthquake on March 31, 1996. These spatial variations in ground motion are hardly ever considered in earthquake analysis of arch dams. When they are included, dam-water-interaction is generally oversimplified. This paper discussed the use of the linear analysis procedure, which includes dam-water-foundation rock interaction effects and recognizes the semi-unbounded extent of the rock and impounded water domains in examining the response of the two arch dams to spatially-varying ground motions recorded during earthquakes. Specifically, the paper discussed the Mauvoisin Dam and earthquake records; system and excitation; influence of spatial variations in ground motion; Pacoima Dam and earthquake records; and influence of spatial variations in excitation. It was concluded that spatial variations in ground motion, typically ignored in dam engineering practice, can have profound influence on the earthquake-induced stresses in the dam. This influence depends on the degree to which ground motion varies spatially along the dam-rock interface. 11 refs., 9 figs.

  15. 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.

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

    OpenAIRE

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

    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 o...

  17. 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.

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

    Directory of Open Access Journals (Sweden)

    Ren Hao

    2008-06-01

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

  19. 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.

  20. 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.

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

    Institute of Scientific and Technical Information of China (English)

    Hong ZHONG; Gao LIN; Hongjun LI

    2009-01-01

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

  2. 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.

  3. 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.

  4. Earthquake analysis of arch and gravity dams including the effects of foundation inhomogeneity

    Institute of Scientific and Technical Information of China (English)

    LIN Gao; DU Jianguo; HU Zhiqiang

    2007-01-01

    Dam-foundation interaction plays an important role in the design of earthquake-resistant concrete arch and gravity dams.Geological conditions of the dam canyon are usually very complicated;however,in the literature,the damfoundation interaction analysis is often carried out based on the premise of a homogeneous unbounded foundation.In this paper,the effect of foundation inhomogeneity on the seismic response of arch and gravity dams was studied by means of scaled boundary finite element method (SBFEM).In order to satisfy the similarity requirement of SBFEM and simplify the computational effort,a subdomain approach and a conical representation of an unbounded foundation were proposed.The way of partitioning the domain and the selection of open angle and bottom radius of the cone model on the accuracy of the result were examined.Numerical examples show that the proposed approach is rational and efficient.Cases of foundation inhomogeneity with stiffness varying in accordance with an exponential function along the radial direction,and cases of foundation inhomogeneity with stiffness discontinuity and with weak interlayer strata on the earthquake response of concrete arch dams as well as gravity dams were analyzed.It was found that a homogeneous idealization of the unbounded foundation may sometimes greatly underestimate the maximum earthquake stress response of the dam.Therefore,taking into account the effect of foundation inhomogeneity for the earthquake safety assessment of concrete arch and gravity dams has great significance.

  5. Experimental Study on Cracking, Reinforcement, and Overall Stability of the Xiaowan Super-High Arch Dam

    Science.gov (United States)

    Lin, Peng; Zhou, Weiyuan; Liu, Hongyuan

    2015-03-01

    The Xiaowan super-high arch dam has faced challenging construction problems. Here, we provide a scientifically-based reference for applying geomechanical model testing to support the nonlinear design of super-high arch dams. We applied experimental similarity theory and techniques. Based on four 3D geomechanical model tests, the dam stress characteristics, deformation distribution, and the safety factors of the dam foundation were identified and compared. We also analyzed cracking characteristics of the up- and downstream dam surfaces and induced joints in the dam heel, the rock mass failure process of the dam-foundation interface, and the abutments. We propose foundation reinforcement measures for weak rock masses, alteration zones, and other faults in the abutments based on the 3D and plane tests each at a different elevation. The results show that all dam deformations remained normal with no yielding or tensile cracking under a normal water load. The reinforced rock mass increased the crack initial safety in the dam heel and toe by ~20 %. The minimum crack initial safety factor ( K 1) of the dam heel was 1.4. The induced joint in the dam heel contributed to a reduction in tensile stress at the upstream dam heel, improving K 1. Compared with similar projects following reinforcement measures, the abutment stiffness and overall stability of the Xiaowan arch dam satisfy operational requirements. Four years of monitoring operations show that key areas near the dam remained normal and the dam foundation is functioning well. Our results may also be applicable to the design and construction of similar projects worldwide.

  6. Mathematical Modeling and Numerical Analysis of Thermal Distribution in Arch Dams considering Solar Radiation Effect

    Directory of Open Access Journals (Sweden)

    H. Mirzabozorg

    2014-01-01

    Full Text Available The effect of solar radiation on thermal distribution in thin high arch dams is investigated. The differential equation governing thermal behavior of mass concrete in three-dimensional space is solved applying appropriate boundary conditions. Solar radiation is implemented considering the dam face direction relative to the sun, the slop relative to horizon, the region cloud cover, and the surrounding topography. It has been observed that solar radiation changes the surface temperature drastically and leads to nonuniform temperature distribution. Solar radiation effects should be considered in thermal transient analysis of thin arch dams.

  7. 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.

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

    Institute of Scientific and Technical Information of China (English)

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

    2011-01-01

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

  9. Seismic analysis of high arch dams considering contraction-peripheral joints coupled effects

    Science.gov (United States)

    Hariri-Ardebili, Mohammad; Mirzabozorg, Hasan; Kianoush, M.

    2013-09-01

    Dam-reservoir interaction is one of the classic coupled problems in which two various environments with different physical characteristics are in contact with each other on interface boundary. Consideration of such interaction is important in design of new dams as well as on safety evaluation of the existing ones. In the present study, the effect of hydrodynamic pressures at various reservoir operational levels on seismic behavior of an arch dam is investigated. Dez ultra-high arch dam in Iran was selected as case study and all contraction and peripheral joints were simulated using node-to-node contact elements which have the ability of opening/closing and tangential movement. In addition, stage construction effects including joint grouting based on available construction reports were considered. The reservoir was assumed to be compressible and the foundation rock was modeled to account for its flexibility. The TABAS earthquake record was used to excite the finite element model of dam-reservoir-foundation system. It was found that dam-reservoir interaction has significant structural effects on the system and generally, operating the considered arch dam at different water levels can highly affects the distribution of the crack prone area under the maximum credible earthquake.

  10. 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.

  11. Mathematical Modeling and Numerical Analysis of Thermal Distribution in Arch Dams considering Solar Radiation Effect

    OpenAIRE

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

    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 drastic...

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

    Directory of Open Access Journals (Sweden)

    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.

  13. 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. PMID:25025089

  14. 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

  15. 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.

  16. Characterization of transient groundwater flow through a high arch dam foundation during reservoir impounding

    Directory of Open Access Journals (Sweden)

    Yifeng Chen

    2016-08-01

    Full Text Available Even though a large number of large-scale arch dams with height larger than 200 m have been built in the world, the transient groundwater flow behaviors and the seepage control effects in the dam foundations under difficult geological conditions are rarely reported. This paper presents a case study on the transient groundwater flow behaviors in the rock foundation of Jinping I double-curvature arch dam, the world's highest dam of this type to date that has been completed. Taking into account the geological settings at the site, an inverse modeling technique utilizing the time series measurements of both hydraulic head and discharge was adopted to back-calculate the permeability of the foundation rocks, which effectively improves the uniqueness and reliability of the inverse modeling results. The transient seepage flow in the dam foundation during the reservoir impounding was then modeled with a parabolic variational inequality (PVI method. The distribution of pore water pressure, the amount of leakage, and the performance of the seepage control system in the dam foundation during the entire impounding process were finally illustrated with the numerical results.

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

    Institute of Scientific and Technical Information of China (English)

    CHEN; HouQun

    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.

  18. Key parameters for single-input earthquake analysis of arch dams

    Energy Technology Data Exchange (ETDEWEB)

    Proulx, J.; Ayala-Paredes, C. [Sherbrooke Univ., PQ (Canada). Dept. of Civil Engineering

    2010-07-01

    An adequate representation of a dam, its water reservoir and its foundation substructure is needed in modeling the earthquake response of concrete dams. Advanced three-dimensional finite element programs include sophisticated models to account for dam-reservoir-foundation interaction. The calibration of such programs and of their key parameters is best achieved by comparing the computed responses to recorded data obtained from on-site investigation or during actual earthquakes. This paper discussed the influence of the modeling parameters for the earthquake analysis of arch dams using single-input motions obtained from recorded earthquake data. The computed accelerations were compared to recordings of moderate earthquakes using three-dimensional numerical models with properties extracted from on-site dynamic test results for a large arch dam in Switzerland. The paper discussed model parameters for the dam, including mesh size; stiffness; damping; and foundation (damping). Several other important parameters related to the reservoir that were presented in a previous study were also briefly summarized. These parameters included geometry; water level; and damping by wave propagation and absorption. It was concluded that although the computation of a foundation impedance matrix could be time consuming, especially for larger models, the use of a finer, more complex mesh is necessary to predict the response in terms of amplitude and frequency content. 10 refs., 1 tab., 7 figs.

  19. The effect of material properties on the seismic performance of Arch Dams

    Science.gov (United States)

    Sevim, B.

    2011-08-01

    The paper investigates the effect of material properties on the seismic performance of arch dam-reservoir-foundation interaction systems based on the Lagrangian approach using demand-capacity ratios. Type-5 arch dam is selected as a numerical application. The linear time history analyses of the arch dam-reservoir-foundation interaction system are carried out for different material properties. The foundation is taken into account as massless; behaviour of the reservoir is assumed to be linearly elastic, inviscid and irrotational. The north-south component of the Erzincan earthquake in 1992 is chosen as a ground motion. Dynamic equations of motions obtained from 3-D finite element modelling of the coupled system are solved by using the Newmark integration algorithm. The damage levels of the coupled system for the different material properties are demonstrated by using demand-capacity ratios and cumulative inelastic durations. The time histories and maximum values of the displacements and principal stresses, and performance curves, are obtained from linear analyses. It is clearly seen from the study that the different material properties affect the seismic behaviour of the dam.

  20. The effect of material properties on the seismic performance of Arch Dams

    Directory of Open Access Journals (Sweden)

    B. Sevim

    2011-08-01

    Full Text Available The paper investigates the effect of material properties on the seismic performance of arch dam-reservoir-foundation interaction systems based on the Lagrangian approach using demand-capacity ratios. Type-5 arch dam is selected as a numerical application. The linear time history analyses of the arch dam-reservoir-foundation interaction system are carried out for different material properties. The foundation is taken into account as massless; behaviour of the reservoir is assumed to be linearly elastic, inviscid and irrotational. The north-south component of the Erzincan earthquake in 1992 is chosen as a ground motion. Dynamic equations of motions obtained from 3-D finite element modelling of the coupled system are solved by using the Newmark integration algorithm. The damage levels of the coupled system for the different material properties are demonstrated by using demand-capacity ratios and cumulative inelastic durations. The time histories and maximum values of the displacements and principal stresses, and performance curves, are obtained from linear analyses. It is clearly seen from the study that the different material properties affect the seismic behaviour of the dam.

  1. 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.

  2. Effects of outlets on cracking risk and integral stability of super-high arch dams.

    Science.gov (United States)

    Lin, Peng; Liu, Hongyuan; Li, Qingbin; Hu, Hang

    2014-01-01

    In this paper, case study on outlet cracking is first conducted for the Goupitan and Xiaowan arch dams. A nonlinear FEM method is then implemented to study effects of the outlets on integral stability of the Xiluodu arch dam under two loading conditions, i.e., normal loading and overloading conditions. On the basis of the case study and the numerical modelling, the outlet cracking mechanism, risk, and corresponding reinforcement measures are discussed. Furthermore, the numerical simulation reveals that (1) under the normal loading conditions, the optimal distribution of the outlets will contribute to the tensile stress release in the local zone of the dam stream surface and decrease the outlet cracking risk during the operation period. (2) Under the overloading conditions, the cracks initiate around the outlets, then propagate along the horizontal direction, and finally coalesce with those in adjacent outlets, where the yield zone of the dam has a shape of butterfly. Throughout this study, a dam outlet cracking risk control and reinforcement principle is proposed to optimize the outlet design, select the appropriate concrete material, strengthen the temperature control during construction period, design reasonable impounding scheme, and repair the cracks according to their classification. PMID:25152907

  3. Elasto-Viscoplastic Block Element Method and its Application to Arch Dam Abutment Slopes

    Science.gov (United States)

    Chen, S.-H.; Shahrour, I.; Egger, P.; Wang, W.-M.

    2002-08-01

    This paper presents an elasto-viscoplastic block element method and its application to the deformation and stability study of arch dam abutment slopes. The paper is composed of two parts. The first part concerns the numerical methods used in the analysis, which includes the identification of the rock blocky system, the algorithm of unconfined seepage flow in discontinuity network taking the grout curtain and drainage curtain into account, and the elasto-viscoplastic block element method as well. In the second part a complicated arch dam abutment slope is studied, from which the seepage flow, the deformation, and the safety factor of the abutment slope are obtained. Based on the analysis suggestions about the seepage control and stabilization measures are made.

  4. A Flexible Network Structure for Temperature Monitoring of a Super High Arch Dam

    OpenAIRE

    Peng Lin; Qingbin Li; Hang Hu

    2012-01-01

    The aim of the study presented in this paper is to develop a flexible network structure for temperature monitoring of a super high arch dam under construction period. The multiple channel temperature acquisition method collects and analyzes system including flexible and stable field bus for the sensors, communication between intelligent module and control unit is proposed. In this temperature monitoring system, a total of 3 kinds of networks which independently marked by ∗(1), ∗(2), and ∗(3) ...

  5. 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.

  6. 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.

  7. 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.

  8. Seismic damage-cracking analysis of arch dams usin8 different earthquake input mechanisms

    Institute of Scientific and Technical Information of China (English)

    PAN JianWen; ZHANG ChuHan; WANG JinTing; XU YanJie

    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 consid-ering 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 sig-nificant. 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 massiess foundation input model, the joint opening and dam-age-cracking of the dam are comparable to the results obtained from the viscous-spring boundary model.

  9. 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.

  10. 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.

  11. 紫江砌石拱坝设计%Design of Zijiang Masonry Arch Dam

    Institute of Scientific and Technical Information of China (English)

    李宗樾

    2014-01-01

    Geohogical defects exist in the original design of growing dam projict for Zijiang hydropowes station .After geological ex-ploration work and comprehensine comparison , adjustment to the design has been made , finally masonry arch has been recommand-ed to be the construction scheme.Because of Zijiang hydropower station of C 15 concrete masonry parabolic thick double -curvature arch dam, stress and stability problems of dam body seepage prevention has been effectively solved , construction difficult reduced , the construction period shortened;for the earlier generation , impounding in phases .Achieved good economic and social benefits .%紫江水电站拦河坝原设计的重力坝方案存在地质缺陷,经补充地勘工作及综合比较,对大坝设计进行复核调整,推选出混凝土砌石拱坝为施工图设计方案。设计大坝为C15混凝土砌石抛物线变厚双曲拱坝,其对地形条件适应性好,有效解决了坝体应力及稳定问题;采用坝体自防渗,降低施工难度、缩短施工工期;为提前发电,采取分期蓄水。取得了良好的经济效益及社会效益。

  12. Analysis of Stability of Gaixia Arch Dam Abutment%盖下拱坝坝肩稳定分析

    Institute of Scientific and Technical Information of China (English)

    房巍; 刘晓青

    2011-01-01

    Taking Gaixia arch dam as the object of the research and combining finite elements and rigid limit equilibrium method to study the stability of Gaixia arch dam abutment in static and dynamic conditions, the anti-slide safety factor of the abutment is obtained. The results satisfy the specification; it is shown that the Gaixia arch dam abutment is safe. The results can be taken as reference for practical projects.%以盖下拱坝为研究对象,结合有限元和刚体极限平衡法,分析了盖下拱坝坝肩岩体在静、动力条件下的稳定性,得到坝肩岩体的抗剪安全系数.所得结果满足规范要求,说明盖下拱坝坝肩是稳定的.研究成果为实际工程提供了参考依据.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. Dams

    OpenAIRE

    Duflo, Esther; Pande, Rohini

    2005-01-01

    The construction of large dams is one of the most costly and controversial forms of public infrastructure investment in developing countries, but little is known about their impact. This paper studies the productivity and distributional effects of large dams in India. To account for endogenous placement of dams we use GIS data and the fact that river gradient affects a district's suitability for dams to provide instrumental variable estimates of their impact. We find that, in a district where...

  20. 大岗山拱坝抗震监测设计%Design of anti-seismic monitoring system for arch dam of Dagangshan Hydropower Station

    Institute of Scientific and Technical Information of China (English)

    王蓉川; 王荣新

    2014-01-01

    大岗山水电站双曲拱坝最大坝高达210 m,坝址区地震基本烈度为Ⅷ度,在国内外已建和在建的200 m级高拱坝中,设计地震动参数最高。简要分析了工程区所面临的来自鲜水河和安宁河地震带的危险性。介绍了坝区及枢纽建筑物强震监测台网布设及其监测数据的传输与处理流程。阐述了国内坝工设计中极少采用的抗震钢筋、阻尼器的布设及其监测系统的设计。%The 210 m double-curvature arch dam of Dagangshan Hydropower Station, located at an area with basic seismic intensity of 8, has the highest earth quake intensity among the 200 m level arch dams built and under building at China and a-broad. The earthquake risks from Xianshuihe and Anninghe seismic zones adjacent to the dam site are analyzed first. The layout of earthquake monitoring network at dam site and the hydraulic structures are presented as well as transmission and processing way of the monitoring data, especially for the anti-seismic steel bars, dampers embedded in dam body and the monitoring system that are rarely adopted in China.

  1. 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.

  2. Safety evaluation of replacement reinforcement quality in abutment contact zones of ultra-high arch dam in first impoundment period based on prototype monitoring

    Directory of Open Access Journals (Sweden)

    Bo HU

    2012-06-01

    Full Text Available Reinforcement quality evaluation at the abutment is an important research direction. Prototype monitoring and theoretical derivation were integrated to study the replacement reinforcement quality in abutment contact zones of the Xiaowan ultra-high arch dam. The principles of monitoring layout and design are introduced in detail. Prototype monitoring shows that the increment of the interfacial compressive stress is much larger in the impoundment stage than in the regulating stage. The water pressure and time-effect are two main factors affecting the interfacial stress. The time-effect is the key factor in the initial impoundment stage, and the water pressure is the key factor after impoundment. The contact properties are significantly improved by grouting. This study shows that there are three typical stages in the joint opening hydrographs, namely the compression stage, opening stage, and stable stage. There is a nonlinear relationship between the joint opening and temperature, which can be well described by the S-function. In conclusion, the reinforcement effect is satisfying, and the abutment is safe.

  3. Study on integral seismic safety of Dagangshan Arch dam-foundation system%大岗山拱坝-地基体系整体抗震安全性研究

    Institute of Scientific and Technical Information of China (English)

    涂劲; 李德玉; 陈厚群; 欧阳金惠

    2011-01-01

    Based on the integral seismic safety concept of clam-foundation system for arch dam, a corre-sponding analytical technique using FEM was developed. In this paper, the seismic safety of Dagangshan Arch Dam subjected to a design peak ground acceleration of 0.5S7 5g resulted in seismic overloading and shear strength reduction of the slide surfaces in the wedges are investigated respectively. In the numerical model, dam-reservoir-foundation interaction and nonlinear contact between contraction joints, dam-founda-tion interface as well as slide surfaces in abutment wedges are taken into account. Both dam body and criti-cal abutment wedge are treated as an integral system and the system safety are determined by one single safety criterion, defined as the point of inflection of the relationship curve between dam displacement and seismic overloading factor or shear strength reduction factor.%基于高拱坝-地基整体抗震安全评价体系,对设计地震动峰值加速度达0.556 5g的大岗山拱坝-地基体系的地震响应进行数值分析,并分别对其在不同地震超载倍数和不同基岩控制性滑裂面抗剪强度降低倍数下的安全性和破坏机理进行研究,以寻求坝体控制性位移或与位移相关的变量随安全系数变化曲线的拐点作为整体失稳判断准则,进一步明确了具体实施方法,并对其整体抗震安全性作出评价.

  4. RESEARCH ON REINFORCEMENT MEASURE OF EMBANKMENT CRACKS OF XIAOWAN ARCH DAM%小湾拱坝坝体裂缝加固措施研究

    Institute of Scientific and Technical Information of China (English)

    张雄; 汪卫明; 陈胜宏

    2011-01-01

    针对小湾坝体出现的裂缝,通过建立2种状态的锚索模型模拟锚索张拉和二次灌浆后的应力状态,利用整体网格和局部子模型相结合的方法,研究坝体内部加锚的可行性以及对锚固区域应力状态和裂缝面性能的影响,并分析化灌对裂缝抗剪强度提高的作用.计算结果表明:400t加锚方案优于100t加锚方案;400t加锚方案中,锚索张拉时在内锚段附近最大拉应力约0.2 MPa,与当前应力相叠加形成新的裂纹的可能性较小.加锚及化灌对裂缝面的抗剪性能有一定的提高,随着水位的升高,其作用越明显.在高水位作用下,部分裂缝出现压剪屈服,建议此区域加大吨位或者采取其他措施.%According to the cracks discovered in the embankment of Xiaowan arch dam, two functional cable models are built to simulate the stress field under the conditions of pulling of prestressed cable and secondary grouting.The feasibility of anchoring in the embankment, and the effects of anchoring on the stress around anchorage region and the performance of crack surfaces are studied by combining integer model and sub-model; and the effect of chemical grouting on reinforcing shear strength of cracks is analyzed.The results indicate that: the anchoring scheme of 400t is superior to the 100t; the maximum tensile stress around bonded length is about 0.2 MPa, which plus current stress may not cause new cracks.The anchoring and chemical grouting can enhance the shear capacity of crack surfaces to some extent; and its effect becomes distinct as the water level rising up.The compression shear yield zones in some cracks appear in the high water level, and large tonnage of anchoring or other measures are suggested to strengthen these areas.

  5. Preliminary Study on the Ultimate Seismic Capacity Evaluation of Concrete Gravity Arch Dam%混凝土重力拱坝极限抗震能力评价方法初探

    Institute of Scientific and Technical Information of China (English)

    张社荣; 王高辉; 王超

    2012-01-01

    从基于性能的抗震设防标准及理论出发,坝体某个关键性能破坏便可能影响大坝的正常运行,单一的评价准则已经不能满足对大坝极限抗震能力评估的要求。针对混凝土重力拱坝的结构特点,基于混凝土弥散裂缝模型,利用地震动超载时域分析方法,从收敛性、地震位移响应突变、塑性区贯通、坝体开裂破坏等方面,对国内某重力拱坝极限抗震能力进行了探讨和研究。研究表明,该重力拱坝的极限抗震能力为0.51g,顶拱中部是坝体相对薄弱的高地震响应区。%From the performance-based standards and the theory of seismic,the destruction of one critical performance may affect the normal operation of the dam,and a single evaluation criterion can not meet the requirement in the assessment of the ultimate aseismic capacity of dam.Based on concrete smeared crack model adopting overloaded time domain analysis method of Ground motionand considering the structural characteristics,the ultimate aseismic capacity of one domestic concrete gravity arch dam was discussed and studied from the convergence,seismic displacement response mutant,interpenetrate of the plastic zone and failure modes of cracks.The result showed that the ultimate aseismic capacity of gravity arch dam is 0.51g,and high seismic response zone locates in the central section.

  6. 基于实测变形的高拱坝力学参数智能优选研究%A Study of Intelligent Optimized Mechanical Parameters of High Arch Dams Based on Measured Deformation

    Institute of Scientific and Technical Information of China (English)

    陈勋辉; 程中凯; 景继; 黄耀英; 万智勇

    2015-01-01

    As the complexity and uncertainty of arch dam body and bedrock ,it is very difficult to obtain calculated parameters accu‐rately .As a result ,the mechanical parameters of high arch dams based on measured deformation is back-analyzed in this paper . Firstly ,by combining the design parameters of comprehensive elastic modulus of dam body and bedrock through uniform design theo‐ries by using the finite element method to obtain the sample of the difference value of water pressure component separated from sever‐al typical points ,then the difference value of water pressure component under water pressure is taken as the import of neural net‐works ,the unknown inverse parameters are taken as outputs correspondingly ,the neural network was established .It was trained to describe the nonlinear relationship between inverse parameters and dam displacements of several typical points .Secondly ,the actual difference value of water pressure component separated from several typical points is input into the trained neural networks to obtain the real material parameters .As an example ,the elastic modulus of dam bodies and rock masses of dam foundations under the base of a high arch dam in southwest are back-analyzed by the above method .It indicates that the difference values of water pressure com‐ponent of several typical points under water pressure were almost the same as the actual difference values ,so it can be concluded that the inversion values are reasonable ,and this inversion method is feasible .%由于高拱坝坝体和基岩工作条件复杂,难以准确给定计算参数,因此,基于实测变形反演高拱坝和基岩力学参数。首先采用均匀设计原理对坝体和基岩综合弹性模量进行设计参数组合,通过有限元正分析得到多个典型测点处坝体的水压分量差值样本,以水压荷载作用下的水压分量差值作为神经网络的输入,对应的待反演参数的样本值作为输出,训练神经网

  7. 层间水力渗透破坏对拱坝工作性态的影响%Influence of working performance of arch dam due to waterpower infiltration and sabotage

    Institute of Scientific and Technical Information of China (English)

    冯帆; 张国新; 刘有志; 李仁江

    2012-01-01

    The waterpower infiltration and sabotage of interlayer crack have a great impact on the working performance of arch dam. In the current paper, combined with an interlayer crack in a 300m-level arch dam, the open-close, sliding and expansion of joints are solved to analyze the waterpower infiltration stabil- ity of the interlayer crack based on the nonlinear iterative method. The results show that if only taking into account the deadweight and the water pressure, the crack is likely to extend upstream and it is difficult to extend downstream. The crack propagation is of low sensitivity for the fracture toughness of concrete, however, showing high sensitive for bond strength after treatment. The loads of temperature can increase the risk of crack propagation; with the conditions of normal load, the crack has little effort on the state of stresses and displacements in arch dam, but has impact on the local area. It will reduce the possibility of the crack propagation slightly when the rock foundation of bank slope is harder than riverbed.%层间裂缝的水力渗透破坏对拱坝工作性态会有较大影响。本文结合某300m级拱坝的一处层间裂缝,基于非线性迭代法求解缝的开闭、滑移和扩展问题,进行了层间裂缝水力渗透的稳定性分析。研究结果表明:只考虑自重和水压作用,裂缝有可能往上游侧扩展,而往下游侧扩展的动力不足;裂缝是否扩展对于混凝土断裂韧度的敏感性较弱,但对于处理后黏结强度的敏感性较强;温升温降荷载会加大裂缝扩展的风险;正常荷载作用条件下,裂缝对拱坝整体应力和位移的影响不大,只对局部区域有一些影响;岸坡岩基较河床硬时,会略微降低该裂缝扩展的可能性;进一步提出做好上游防渗及钻孔形成排水通道等建议。

  8. Experimental Research on Shear Resistance of High Arch Dam Concrete in Situ%高拱坝混凝土原位抗剪试验研究

    Institute of Scientific and Technical Information of China (English)

    吴峰涛

    2014-01-01

    通过对混凝土层间结合面进行原位抗剪试验,获得各级配混凝土不同层间处理方式的极限抗剪强度、残余抗剪强度、摩擦强度和抗剪特性参数f′、c′,为优化大坝混凝土层间处理措施、评估坝体结构稳定性提供依据。%Based on in - situ shear tests of concrete interlayer bonding obtained the ultimate shear strength ,residual shear strength ,friction strength and shear parameters (C′,f′) of concrete with different grading and different process mode of interlayer .Provide the basis for optimizing the measurements of dam con‐crete layer and for assessment of structural stability of the dam .

  9. 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%.

  10. Concrete Mix Proportion Design for the Arch Dam of Tianhuaban Hydropower Station%天花板水电站拱坝混凝土配合比设计及应用

    Institute of Scientific and Technical Information of China (English)

    王毅鸣; 苏岩; 徐天尧

    2011-01-01

    The dam of Tianhuaban Hydropower Station is a roller-compacted concrete double-curvature arch dam. The mix proportion selection for the RCC and normal concrete being used in the project is a key technical issue. The indicator requirements, parameter definitions and raw material selections for concrete mix proportion design are analyzed and tested by the design, research and construction departments during different design stages, and the final mix proportions are proposed.The actual practice shows that the final mix proportions are advanced in technology and significant in economy, and can further reduce the temperature rise of concrete.%天花板水电站大坝为碾压混凝土双曲拱坝,拱坝碾压混凝土和大坝常态混凝土配合比是工程的关键技术问题.设计、科研和施工单位在不同设计阶段针对混凝土配合比设计的指标要求、参数确定和原材料选择进行了研究和试验,确定了最终的施工配合比调整方案.实际应用表明,调整的混凝土配合比技术先进、经济效益明显,并进一步降低了拱坝坝体施工过程中混凝土的温升.

  11. 混凝土拱坝取料平台防撞装置设计与应用%Design of the Anti-collision Device in Concrete Loading Platform in the Construction of Arch Dams and Its Application

    Institute of Scientific and Technical Information of China (English)

    黄浩

    2014-01-01

    In order to alleviate the damage of the concrete loading platform due to collision with the charging bucket in the pouring process of arch dams , a steel runner cushion device which could reduce the impact of collision is designed . Practice shows an evident anti-collision effect of such device .Compared with similar projects , construction materials such as steel and wood are greatly saved .%为了减少电站拱坝浇筑取料料罐在回程取料过程中,对取料平台冲击破坏,设计了钢面板滑槽缓冲装置,以减少料罐对平台的冲击力。通过应用,防冲撞效果十分明显,与同类工程相比,节约了大量的钢材、木材等材料。

  12. 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.

  13. Norwegian dams

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, Inge (ed.)

    2009-07-01

    The magnificent work 'Norwegian dams' consists of two volumes. It presents and proves more than 300 hydro power dams throughout Norway. Pictures of beautiful dams which provide eternal, renewable and anti pollutant hydropower. (AG)

  14. 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.

  15. Management of dams for the next Millennium: proceedings of the 1999 Canadian Dam Association

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-07-01

    The meeting featured seven sessions with 18 papers abstracted/indexed therein as follows: keynote address: tailings dams safety - implications for the dam safety community; 1 - design and performance: performance monitoring of dams: are we doing what we should be doing?; tailings dams from the perspective of conventional dam engineering; and design overview of Syncrude's Mildred Lake east toe berm; 2 - design and modelling: use of a 2D model for a dam break study on the ALCAN hydroelectric complex in Quebec; and spillway design implications resulting from changes in rainfall extremes; 3 - risk and dam safety I: closing the gaps in the dam safety guidelines; the reality of life safety consequence classification; and surveillance practices for the next millenium; 4 - risk and dam safety II: quantitative risk-assessment using the capacity-demand analysis; and new guidelines for dam safety classification; 5 - millenium issues: expectations of immortality, dam safety management into the next millenium; 6 - rehabilitation techniques: the unconventional application of conventional materials; nondestructive testing technology to characterize concrete dam/bedrock interface; method and instrument for detecting crack in concrete; and grouting of the cracks in the Arch 5-6 - Daniel Johnson Dam; and 7 - case studies: rehabilitation of an 80 year old Ambursen type dam; and debris booms for the protection of spillways.

  16. Aortic arch malformations

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-06-15

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

  17. 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...

  18. Rubber Dams

    OpenAIRE

    Kumaraswamy, Mohan

    2002-01-01

    One element of the CIVCAL project Web-based resources containing images, tables, texts and associated data on the construction of the Rubber Dams. Rubber dam construction is a relatively recent technological breakthrough. It was introduced to Hong Kong in the early 1960's and to date (Jan '99), 20 rubber dams have been installed in Hong Kong. Most of the dams are used to impound water for irrigation.

  19. 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

  20. 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.

  1. 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...

  2. Incremental elastic finite element iterative method for solution of ultimate load of arch dams%求解拱坝极限荷载的增量弹性有限元迭代法

    Institute of Scientific and Technical Information of China (English)

    钱向东; 钮如嵩

    2016-01-01

    In order to avoid large amounts of computation with the elastic compensation method, the incremental elastic finite element iterative method ( IEFEIM) is proposed for solution of the ultimate load of complex structures, based on the advantages of elastic⁃plastic analysis and plastic limit analysis. With the load factor β as a variable, and by using the self⁃adaptive increment adjustment technique, the maximum load factor βmax satisfying the equilibrium and yield conditions is obtained by iteration and approximation. In contrast to the elastic⁃plastic analysis method, the IEFEIM only requires the strength criterion of materials and does not require the constitutive relationship of materials after yielding and failure; in contrast to the plastic limit analysis method, the IEFEIM obtains the maximum load factor by directional search and approximation, without using the programming algorithm for large⁃scale search;and in contrast to the elastic compensation method, the IEFEIM generates the global stiffness matrix for only one time, without any need of generating the global stiffness matrix for each step, effectively decreasing the amount of computation in iterations. Practical application in engineering projects shows that the IEFEIM can obtain the ultimate load of high dams effectively and provide the structural characteristics close to the ultimate state.%为了克服弹性补偿法每一步计算量太大的问题,结合弹塑性分析法和塑性极限分析法的优点,提出求解复杂结构极限荷载的增量弹性有限元迭代法( IEFEIM)。该方法以荷载因子β为变量,采用自适应增量调整技术,迭代逼近满足平衡条件和屈服条件的最大荷载因子βmax。与弹塑性分析法相比,IEFEIM只需材料的强度准则,不需要材料屈服、破坏后的本构关系;与塑性极限分析法相比,IEFEIM只需增量定向搜索逼近荷载因子最大值,无需开展大范围搜索的规划算法;

  3. Burmese Arched Harp

    Science.gov (United States)

    Williamson, Robert M.

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

  4. 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/

  5. 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

  6. 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.

  7. 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.

  8. Semi- and Nonparametric ARCH Processes

    Directory of Open Access Journals (Sweden)

    Oliver B. Linton

    2011-01-01

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

  9. Simple Way of Recording Dental Arch Forms

    OpenAIRE

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

    2015-01-01

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

  10. Classification of Dams

    OpenAIRE

    Berg, Johan; Linder, Maria

    2013-01-01

    In a comparing survey this thesis investigates classification systems for dams in Sweden, Norway, Finland, Switzerland, Canada and USA. The investigation is aiming at an understanding of how potential consequences of a dam failure are taken into account when classifying dams. Furthermore, the significance of the classification, regarding the requirements on the dam owner and surveillance authorities concerning dam safety is considered and reviewed. The thesis is pointing out similarities and ...

  11. 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.

  12. Experimental behavior of FRP strengthened masonry arches

    OpenAIRE

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

    2010-01-01

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

  13. 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.

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

    OpenAIRE

    Zohreh Hedayati; Farnaz Fakhri; Vahid Moshkel Gosha

    2015-01-01

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

  15. 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.

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

    Directory of Open Access Journals (Sweden)

    Zohreh Hedayati

    2015-06-01

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

  17. 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…

  18. Small dams in Canada

    Energy Technology Data Exchange (ETDEWEB)

    Grapel, C.K. [EBA Engineering Consultants Ltd., Edmonton, AB (Canada); Mitchelmore, P. [Mitchelmore Engineering Co. Ltd., Halifax, NS (Canada)

    2009-07-01

    Small dams are often used for irrigation, municipal water supplies and storm water management. Small dams outnumber large hydro-electric projects in Canada by a wide margin, and tend to be located closer to large population centres. Despite their lower profile with the general public, small dams frequently have high consequence classifications. This study discussed the distribution of various consequence classifications for small dams of varying heights. Databases from different Canadian provinces were used to develop sets of statistics on dam features, the distribution of risk, and other relevant information. Approximately 6000 dams were classified in the database. Of these, 444 were greater than 15 metres in height. A significant portion of with high consequence classifications qualified as small dams, and the majority of the high consequence dams were under 10 metres in height. The largest population of dam owners have limited resources available for adequate engineering design, construction supervision, and dam safety management programs. It was concluded that economical methods of estimating probable maximum flood (PMF) rates are needed for small dams. 8 refs., 5 tabs., 2 figs.

  19. Mechanics of slide dams

    International Nuclear Information System (INIS)

    Studies which promote the use of nuclear energy for peaceful projects in engineering are sponsored by the Atomic Energy Commission under the Plowshare program. Specific projects being considered include the construction of harbors, canals, and dams. Of these projects, perhaps the most difficult to accomplish will be the latter. This paper which is in two parts considers the problems which are associated with the construction of slide dams with nuclear explosives. It examines first the characteristics of conventional earth and rock-fill dams which are based upon proven techniques developed after many years of experience. The characteristics of natural landslide dams are also briefly considered to identify potential problems that must be overcome by slide dam construction techniques. Second, the mechanics of slide dams as determined from small-scale laboratory studies are presented. It is concluded that slide dams can be constructed and that small-scale field tests and additional laboratory studies are justified. (author)

  20. Public safety around dams

    Energy Technology Data Exchange (ETDEWEB)

    Bechai, M. [MOBEC Engineering, North York, ON (Canada)

    2009-07-01

    The purpose of dam safety is to prevent an uncontrolled release of water and to have emergency preparedness plans in place in the event of failure. This presentation discussed dam and public safety around dams. Public safety around dams involves the safe management of water during normal operations, including intake water; discharge from turbines; and spill events. Public safety measures are intended to ensure the security of the site to minimize public exposure to hazards. The objectives of the presentation were to discuss the current state of industry practice in regards to public safety around dams and to provide input to the draft Canadian Dam Association guidelines for public safety around dams. The presentation also discussed the principles that would govern preparation of the guidelines and regulator's views on the public safety issues. figs.

  1. 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.

  2. Tailings dams from the perspective of conventional dam engineering

    International Nuclear Information System (INIS)

    A guideline intended for conventional dams such as hydroelectric, water supply, flood control, or irrigation is used sometimes for evaluating the safety of a tailings dam. Differences between tailings dams and conventional dams are often substantial and, as such, should not be overlooked when applying the techniques or safety requirements of conventional dam engineering to tailings dams. Having a dam safety evaluation program developed specifically for tailings dams is essential, if only to reduce the chance of potential errors or omissions that might occur when relying on conventional dam engineering practice. This is not to deny the merits of using the Canadian Dam Safety Association Guidelines (CDSA) and similar conventional dam guidelines for evaluating the safety of tailings dams. Rather it is intended as a warning, and as a rationale underlying basic requirement of tailings dam emgineering: specific experience in tailings dams is essential when applying conventional dam engineering practice. A discussion is included that focuses on the more remarkable tailings dam safety practics. It is not addressed to a technical publications intended for such dams, or significantly different so that the use of conventional dam engineering practice would not be appropriate. The CDSA Guidelines were recently revised to include tailings dams. But incorporating tailings dams into the 1999 revision of the CDSA Guidelines is a first step only - further revision is necessary with respect to tailings dams. 11 refs., 2 tabs

  3. Tailings dams from the perspective of conventional dam engineering

    Energy Technology Data Exchange (ETDEWEB)

    Szymanski, M.B. [AGRA, Mississauga, ON (Canada)

    1999-07-01

    A guideline intended for conventional dams such as hydroelectric, water supply, flood control, or irrigation is used sometimes for evaluating the safety of a tailings dam. Differences between tailings dams and conventional dams are often substantial and, as such, should not be overlooked when applying the techniques or safety requirements of conventional dam engineering to tailings dams. Having a dam safety evaluation program developed specifically for tailings dams is essential, if only to reduce the chance of potential errors or omissions that might occur when relying on conventional dam engineering practice. This is not to deny the merits of using the Canadian Dam Safety Association Guidelines (CDSA) and similar conventional dam guidelines for evaluating the safety of tailings dams. Rather it is intended as a warning, and as a rationale underlying basic requirement of tailings dam emgineering: specific experience in tailings dams is essential when applying conventional dam engineering practice. A discussion is included that focuses on the more remarkable tailings dam safety practics. It is not addressed to a technical publications intended for such dams, or significantly different so that the use of conventional dam engineering practice would not be appropriate. The CDSA Guidelines were recently revised to include tailings dams. But incorporating tailings dams into the 1999 revision of the CDSA Guidelines is a first step only - further revision is necessary with respect to tailings dams. 11 refs., 2 tabs.

  4. Public safety around dams

    Energy Technology Data Exchange (ETDEWEB)

    Bourassa, H. [Centre d' expertise hydrique du Quebec, Quebec, PQ (Canada)

    2009-07-01

    Fourty public dams are managed on a real-time basis by the Centre d'expertise hydrique du Quebec (CEHQ). This presentation described the public dams owned by the CEHQ and discussed the public safety measures at the dams. The dams serve various purposes, including protection against floods; industrial or drinking water supply; resort or recreational activities; hydroelectric development; and wildlife conservation. Trigger events were also discussed, such as the complaint at Rapides-des-Cedres dam and deaths that occurred in 2004 when water from a dam was released without warning. Several photographs were presented to illustrate that people were unaware of the danger. Initiatives aimed at raising awareness and studying public safety issues were discussed. A pilot project was launched and a permanent committee was created to evaluate all aspects of public safety at the dams owned by CEHQ. The first tasks of the committee were to establish requirements for waterway safety barriers, both upstream and downstream, for all public dams; to establish requirements for safety signage for all public dams; and to develop criteria to decide on safety signage at each dam. figs.

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

    Directory of Open Access Journals (Sweden)

    Rakhn G. Al-Barakati

    2016-01-01

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

  6. 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.

  7. Update on Elsie Dam

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    BC Hydro has now completed work on stage 1 of the Elsie dam upgrade in Vancouver lsland, Canada.The dam, part of the 27MW Ash river hydroelectric facility built in 1958, is being upgraded to resists major seismic events. Darn safety investigations had shown that a thin layer of saturated loose material in the main dam at approximately el 326m would liquefy during a major earthquake.

  8. 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.

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

    Science.gov (United States)

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

    2015-01-01

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

  10. Techniques for aortic arch endovascular repair.

    Science.gov (United States)

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

    2016-06-01

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

  11. 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.

  12. Reported tailings dam failures

    Energy Technology Data Exchange (ETDEWEB)

    Rico, M. [CSIC - Instituto Pirenaico de Ecologia, Zaragoza (Spain)], E-mail: mayterico@ipe.csic.es; Benito, G. [CSIC - Centro de Ciencias Medioambientales, Madrid (Spain); Salgueiro, A.R. [CERENA - Centro de Recursos Naturais e Ambiente of IST, Lisboa (Portugal); Diez-Herrero, A. [Geological Hazards Unit, Spanish Geological Survey (IGME), Madrid (Spain); Pereira, H.G. [CERENA - Centro de Recursos Naturais e Ambiente of IST, Lisboa (Portugal)

    2008-04-01

    A detailed search and re-evaluation of the known historical cases of tailings dam failure was carried out. A corpus of 147 cases of worldwide tailings dam disasters, from which 26 located in Europe, was compiled in a database. This contains six sections, including dam location, its physical and constructive characteristics, actual and putative failure cause, sludge hydrodynamics, socio-economical consequences and environmental impacts. Europe ranks in second place in reported accidents (18%), more than one third of them in dams 10-20 m high. In Europe, the most common cause of failure is related to unusual rain, whereas there is a lack of occurrences associated with seismic liquefaction, which is the second cause of tailings dam breakage elsewhere in the world. Moreover, over 90% of incidents occurred in active mines, and only 10% refer to abandoned ponds. The results reached by this preliminary analysis show an urgent need for EU regulations regarding technical standards of tailings disposal.

  13. Reported tailings dam failures

    International Nuclear Information System (INIS)

    A detailed search and re-evaluation of the known historical cases of tailings dam failure was carried out. A corpus of 147 cases of worldwide tailings dam disasters, from which 26 located in Europe, was compiled in a database. This contains six sections, including dam location, its physical and constructive characteristics, actual and putative failure cause, sludge hydrodynamics, socio-economical consequences and environmental impacts. Europe ranks in second place in reported accidents (18%), more than one third of them in dams 10-20 m high. In Europe, the most common cause of failure is related to unusual rain, whereas there is a lack of occurrences associated with seismic liquefaction, which is the second cause of tailings dam breakage elsewhere in the world. Moreover, over 90% of incidents occurred in active mines, and only 10% refer to abandoned ponds. The results reached by this preliminary analysis show an urgent need for EU regulations regarding technical standards of tailings disposal

  14. Tailings dams safety - implications for the dam safety community

    International Nuclear Information System (INIS)

    In the context of the impact of privatization and globalization on traditional dam safety practice and the Canadian experience of the environmental dimension of dam failures, various aspects of tailings dam safety have much to offer the wider dam safety community. General design principles for tailings dams are not described, rather an attempt is made to frame some contemporary issues of tailings dam safety in ways that bring out their relevance in a broader dam safety context. Lessons applicable to future dam safety practice in related areas are examined, and the dam safety traditions of the mining, hydroelectric and related industries in Canada are brought together by illustrating some of the common elements and concerns they share. It is becoming evident that future dam safety activities for the hydroelectric, water supply and related dams will be carried out in a more privatized and globalized context by organizations less acquainted with traditional dam safety practices than in the past. If so, then tailings dam experience can be a pathfinder for how and why dam safety needs to be addressed in a corporate setting. It shows that the perceived effects of dam failures, environmental and otherwise, influence corporate damowners in ways that can amplify manyfold the objective consequences that dam safety assessments usually address. Dam safety professionals might do well to better understand and effectively communicate the financial and organizational impacts of dam failure on the corporate entity in ways that go beyond the traditional assessment of downstream hazard and failure consequences. Dam safety efforts can come to be seen less as imposed burdens of dam ownership and more as activities consistent with shareholder accountability and corporate self-interest. The Canadian mining industry, in adopting this perspective, is confirming that support for dam safety activities from the highest corporate level is essential for implementing them throughout the

  15. Tailings dams safety - implications for the dam safety community

    Energy Technology Data Exchange (ETDEWEB)

    Vick, S.G.

    1999-07-01

    In the context of the impact of privatization and globalization on traditional dam safety practice and the Canadian experience of the environmental dimension of dam failures, various aspects of tailings dam safety have much to offer the wider dam safety community. General design principles for tailings dams are not described, rather an attempt is made to frame some contemporary issues of tailings dam safety in ways that bring out their relevance in a broader dam safety context. Lessons applicable to future dam safety practice in related areas are examined, and the dam safety traditions of the mining, hydroelectric and related industries in Canada are brought together by illustrating some of the common elements and concerns they share. It is becoming evident that future dam safety activities for the hydroelectric, water supply and related dams will be carried out in a more privatized and globalized context by organizations less acquainted with traditional dam safety practices than in the past. If so, then tailings dam experience can be a pathfinder for how and why dam safety needs to be addressed in a corporate setting. It shows that the perceived effects of dam failures, environmental and otherwise, influence corporate damowners in ways that can amplify manyfold the objective consequences that dam safety assessments usually address. Dam safety professionals might do well to better understand and effectively communicate the financial and organizational impacts of dam failure on the corporate entity in ways that go beyond the traditional assessment of downstream hazard and failure consequences. Dam safety efforts can come to be seen less as imposed burdens of dam ownership and more as activities consistent with shareholder accountability and corporate self-interest. The Canadian mining industry, in adopting this perspective, is confirming that support for dam safety activities from the highest corporate level is essential for implementing them throughout the

  16. Public safety around dams

    Energy Technology Data Exchange (ETDEWEB)

    Pastinak, O. [Ontario Ministry of Natural Resources, Toronto, ON (Canada)

    2009-07-01

    Ontario's current dam safety program is administered under guidelines and there is no regulation in place. It is a reactive program that is administered by area supervisors and regional engineers with support from policy, legal and enforcement branches. Currently, there are no regulatory requirements for inspections, dam classifications, public safety measures, emergency preparedness plans, operations and maintenance, or dam registration. This presentation proposed improvements to Ontario's current dam safety program and highlighted the imperatives for public safety around dams. The presentation also discussed the proposed elements of enhanced public safety requirements. The proposed measures would involve moving from a reactive, guidelines-based program to a regulated program under the Lakes and Rivers Improvement Act. The presentation discussed why public safety around dams should be regulated and provided an overview of dam related fatalities in Ontario. A public safety framework and public safety assessment report were also discussed. Registration of incidents and public safety measures were addressed. figs.

  17. 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.

  18. 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...

  19. Remediation of tailings dams

    International Nuclear Information System (INIS)

    Environmental effects from mining activities occur in all phases, beginning with exploration, then creation of pits and waste dumps, and finally processing of ore and handling tailings. A tailings dam must ensure physical, radioactive and chemical safety for both the environment and the public during operation and after closure. Three fundamental failure mechanisms of dam stability must be considered to ensure physical stability and adequate containment of the radioactive material

  20. 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.

  1. Multichannel Analysis of Surface Waves and Dam Safety

    Science.gov (United States)

    Karastathis, V. K.

    2012-12-01

    by the differential settlement of the dam and more specifically by the arching phenomenon in the core. Such phenomena can lead to hydraulic fracture in the core and therefore should be carefully encountered. In particular the method detected, in the central part of the core, a weak zone just below the crest and another one at depth of 45 below crest, at a place where the monitoring instruments of the dam had measured very low effective stresses. This zone follows the shape pattern of the riverbed and at the edges of the crest it is connected with two other thick tensile zones. The example from the application in the concrete dam at Marathon is focused on the interior of the dam. The data acquired there, in the tunnels, were of different character than the ones gathered on usual applications on soil environment mainly due to the high and broad frequency content and the high phase velocity values. The standard data acquisition procedure also required some modification for the triggering and recording. The analysis of the data showed that such an application could provide useful results for the testing of the concrete quality.

  2. Dams and Intergovernmental Transfers

    Science.gov (United States)

    Bao, X.

    2012-12-01

    Gainers and Losers are always associated with large scale hydrological infrastructure construction, such as dams, canals and water treatment facilities. Since most of these projects are public services and public goods, Some of these uneven impacts cannot fully be solved by markets. This paper tried to explore whether the governments are paying any effort to balance the uneven distributional impacts caused by dam construction or not. It showed that dam construction brought an average 2% decrease in per capita tax revenue in the upstream counties, a 30% increase in the dam-location counties and an insignificant increase in downstream counties. Similar distributional impacts were observed for other outcome variables. like rural income and agricultural crop yields, though the impacts differ across different crops. The paper also found some balancing efforts from inter-governmental transfers to reduce the unevenly distributed impacts caused by dam construction. However, overall the inter-governmental fiscal transfer efforts were not large enough to fully correct those uneven distributions, reflected from a 2% decrease of per capita GDP in upstream counties and increase of per capita GDP in local and downstream counties. This paper may shed some lights on the governmental considerations in the decision making process for large hydrological infrastructures.

  3. 梯级水库群洪水溃坝模拟%Simulation of Dam Break Flood for Cascade Reserviors

    Institute of Scientific and Technical Information of China (English)

    刘庆红; 付湘; 何海源; 张秀丽; 杜德进; 刘光保

    2011-01-01

    In this paper, a detailed dam break analysis for seven cascading dams in the transnational river has been carried out using MIKE 11 Dam Break model. The form of dam breach and patterns are set for different dam types (earth and rockfill dam, arch dam and concrete gravity dam). The study consists of two hypothetical Scenarios of failure: failure of dam due to overtopping for all types of dams; failure of earth and rockfill dams while safety for gravity concrete dams and arch dams due to overtopping. The model computes reservoirs outflows and flood routing from breach to downstream due to extraordinary flood of major flood season and floodending season. The maximum flood level at different cross sections of the river and travel time of the flood waves at different dams locations along the river are predicted. The results of the dam break analysis can provide a scientific basis for evacuation plans and risk assessment in the affected area.%以某河流的7个梯级水库为研究对象,合理地拟定各梯级水库不同大坝类型(土石坝、拱坝、混凝土重力坝)的溃决形式、溃口发生过程及形态,针对各类型水库漫顶即溃坝和土石坝漫顶溃坝,拱坝、重力坝漫顶过流不产生溃坝两种极限状态,运用Dam Break溃坝模型原理,计算主汛期超标准洪水和后汛期超标准洪水时梯级水库的连锁响应以及溃坝洪水向下游库群的演进过程.分析流城内各水库清坝发生的因果关系,并得出各水库溃坝发生的相对时间及各特征断面的最高水位、流量等特征值.汛期超标准洪水时流城梯级水库的溃坝模拟分析结果,为降低大坝风险、制定应急预案和防灾减灾提供了科学的决策依据.

  4. 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.

  5. Dam Safety Instrumentation

    Directory of Open Access Journals (Sweden)

    P. R. Bamane

    2014-06-01

    Full Text Available In most of the cases, the materials are tested in laboratories and designs are based on assumptions that the same results will be met with, during actual construction. As there are always large variations in materials, their properties, construction methods and their control, the actual product defers from the original assumptions. In this paper, instruments required to check the behaviour and stability of dams are discussed with their necessity, use and operation. These instruments prove to be much useful in proper maintenance of dam, and hence they should be installed under the guidance of experts at appropriate places in the dam. A conclusion has been arrived that there should be close co-operation between the designers, instrumentation specialist, expert analysis and site authorities to achieve the goal of instrumentation.

  6. Skyscraper dams in Yunnan : China's new electricity generator should step in

    Energy Technology Data Exchange (ETDEWEB)

    Ryder, G.

    2006-05-12

    The construction of a series of high-head hydroelectric power dams in China's earthquake-prone Yunnan province has raised concerns in China's scientific and environmental communities. The series of skyscraper-high dams are being built to meet Beijing's power production targets without the benefit of market discipline or effective regulatory oversight. Dam building is central to Beijing's plan for tripling the country's hydropower production by 2020. To meet that target, the State Council granted exclusive development rights to Hydrolancang, the Yunnan Huadian Nu River Hydropower Development Company and the Three Gorges Corporation. The Hydrolancang company is building 2 of the world's tallest and most controversial hydro dams on the Lancang River. When completed in 2012, Xiaowan will be the world's tallest arch dam at 292 metres high. Another dam, the 254 metre high Nuozhadu dam is expected to start generating power in 2017. In addition, there are plans for 13 other high dams along the Nu River, one of only 2 major rivers in China that remains free-flowing. This document expressed that China's new electricity regulator should initiate a full-cost review of state dam-building in the earthquake-prone province. It was argued that as state-owned power companies, the dam builders are not market-driven and are shielded from many of the financial risks and environmental liabilities associated with large dams. The author argued that China's electricity regulator should examine the dam builders' projects costs and profits and review the economic implications of the hydro policy for China's power consumers. It was also suggested that the country's modernization goals for the power industry should be reviewed. The immediate concerns are ecological damage and the frequency with which Yunnan province is hit by earthquakes, rock falls and landslides. Experts caution that the extra weight of the high dams and reservoirs

  7. 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.

  8. 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.

  9. Recent waterway incidents around dams

    Energy Technology Data Exchange (ETDEWEB)

    Rowat, L. [Ontario Power Generation Inc., Niagara Falls, ON (Canada)

    2009-07-01

    This presentation discussed recent waterway incidents around dams. Several case histories were presented, including a man who drowned when he slipped from the top of the South Idaho Power Plant Spillway in June 3 2004; 2 brothers who drowned near a spillway in Watson Minnesota, in June, 2004; a jet-skier who plunged to his death after ramping the 50 foot Brasfield Dam, in Virginia in June, 2004; a couple whose boat on Lake Austin was swept up against the sluicegate; an angler who drowned at a dam in Bridgeville, Delaware; a man who drowned swimming below a dam in San Marcos, Texas in April, 2005; and a fisherman who drowned at Logan Martin Dam in Birmingham, Alabama in April, 2005. A list of examples of fatalities at dams in 2004 and international incidents at dams from 2005 and 2006 to 2008 were also provided. Examples of Canadian incidents at dams were also listed. figs.

  10. Dam health diagnosis and evaluation

    Science.gov (United States)

    Wu, Zhongru; Su, Huaizhi

    2005-06-01

    Based on the bionics principle in the life sciences field, we regard a dam as a vital and intelligent system. A bionics model is constructed to observe, diagnose and evaluate dam health. The model is composed of a sensing system (nerve), central processing unit (cerebrum) and decision-making implement (organism). In addition, the model, index system and engineering method on dam health assessment are presented. The proposed theories and methods are applied to evaluate dynamically the health of one concrete dam.

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

    OpenAIRE

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

    2003-01-01

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

  12. 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 ...

  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 cables, the rise to span ratio, the height of the filling, and the height of the Super-Light Decks. We find that Pearl-Chain Bridges can be adjusted to resist specific moment loads by changing the normal force in the arch cross section by altering the above parameters. It is also found that the negative...

  14. Arch Coal focuses on its future

    International Nuclear Information System (INIS)

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

  15. Expansion at Olympic Dam

    International Nuclear Information System (INIS)

    The Olympic Dam orebody is the 6th largest copper and the single largest uranium orebody in the world. Mine production commenced in June 1988, at an annual production rate of around 45,000 tonnes of copper and 1,000 tonnes of uranium. Western Mining Corporation announced in 1996 a proposed $1.25 billion expansion of the Olympic Dam operation to raise the annual production capacity of the mine to 200,000 tonnes of copper, approximately 3,700 tonnes of uranium, 75,000 ounces of gold and 950,000 ounces of silver by 2001. Further optimisation work has identified a faster track expansion route, with an increase in the capital cost to $1.487 billion but improved investment outcome, a new target completion date of end 1999, and a new uranium output of 4,600 tonnes per annum from that date

  16. Dam spills and fishes

    International Nuclear Information System (INIS)

    This short paper reports the main topics discussed during the two days of the annual colloquium of the Hydro-ecology Committee of EdF. The first day was devoted to the presentation of the joint works carried out by EdF, the Paul-Sabatier University (Toulouse), the Provence St-Charles University (Marseille), the ENSAT (Toulouse) and the CEMAGREF (Lyon and Aix-en-Provence) about the environmental impact of dam spills on the aquatic flora and fauna downstream. A synthesis and recommendations were presented for the selection and characterization of future sites. The second day was devoted to the hydro-ecology study of the dam reservoir of Petit-Saut (French Guyana): water reoxygenation, quality evolution, organic matter, plankton, invertebrates and fishes. The 134 French dams concerned by water spills have been classified according to the frequency of spills, the variations of flow rates created, and their impacts on fishing, walking, irrigation, industry, drinking water, navigation, bathing. Particular studies on different sites have demonstrated the complexity of the phenomena involved concerning the impact on the ecosystems and the water quality. (J.S.)

  17. 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.

  18. Brain vasopressin is an important regulator of maternal behavior independent of dams' trait anxiety

    Science.gov (United States)

    Bosch, Oliver J.; Neumann, Inga D.

    2008-01-01

    The neuropeptide arginine vasopressin (AVP) is arguably among the most potent regulators of social behaviors in mammals identified to date. However, only the related neuropeptide oxytocin (OXT) has been shown to promote maternal behavior. Here, we assess the role of AVP in maternal care, in particular in arched back nursing, pup retrieval, and pup contact by using complementary pharmacological and genetic approaches. Also, experiments were performed in rat dams with differences in trait anxiety, i.e., rats bred for either high (HAB) or low (LAB) anxiety-related behavior as well as nonselected (NAB) dams. Viral vector-mediated up-regulation of AVP V1a receptors (AVP-Rs) within the medial preoptic area of lactating NAB rats and chronic central AVP treatment of NAB and LAB dams improved, whereas local blockade of AVP-R expression by means of antisense oligodeoxynucleotides or central AVP-R antagonism impaired, maternal care in NAB dams. Also, in HAB rats with a genetically determined elevated brain AVP activity, intrinsically high levels of maternal care were reversed by blockade of AVP-R actions. Treatment-induced impairment of AVP-mediated maternal behavior increased adult emotionality and impaired social interactions in male offspring of NAB dams. These findings provide direct evidence for an essential and highly potent role of brain AVP in promoting maternal behavior, which seems to be independent of the dam's trait anxiety. PMID:18955705

  19. 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.

  20. 1000 dams down and counting

    Science.gov (United States)

    O'Connor, James E.; Duda, Jeff J.; Grant, Gordon E.

    2015-01-01

    Forty years ago, the demolition of large dams was mostly fiction, notably plotted in Edward Abbey's novel The Monkey Wrench Gang. Its 1975 publication roughly coincided with the end of large-dam construction in the United States. Since then, dams have been taken down in increasing numbers as they have filled with sediment, become unsafe or inefficient, or otherwise outlived their usefulness (1) (see the figure, panel A). Last year's removals of the 64-m-high Glines Canyon Dam and the 32-m-high Elwha Dam in northwestern Washington State were among the largest yet, releasing over 10 million cubic meters of stored sediment. Published studies conducted in conjunction with about 100 U.S. dam removals and at least 26 removals outside the United States are now providing detailed insights into how rivers respond (2, 3).

  1. 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.

  2. Biotechnologie des archées

    OpenAIRE

    Querellou, Joel

    2010-01-01

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

  3. 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

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

    Science.gov (United States)

    Tsai, Hung-Huey

    2003-01-01

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

  5. Neural Network in Developing Software for Indentifying Arch Form

    Directory of Open Access Journals (Sweden)

    Johan Arief Budiman

    2013-06-01

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

  6. Grouting Applications in Cindere Dam

    OpenAIRE

    Alkaya, Devrim; Burak YEŞİL

    2011-01-01

    Grouting is one of the most popular method to control the water leakage in fill dam constructions. With this regard this method is widely used in all the world. Geological and geotechnical properties of rock are important parameters affect the design of grouting. In this study, geotechnical properties of Cindere Dam's base rock and the grouting prosedure have been investigated with grouting pressure.

  7. 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.

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

    OpenAIRE

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

    2016-01-01

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

  9. 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.

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

    Institute of Scientific and Technical Information of China (English)

    Leng Fei; Lin Gao

    2008-01-01

    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.

  11. 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.

  12. Damming evidence : Canada and the World Commission on Dams

    Energy Technology Data Exchange (ETDEWEB)

    Vert, P.; Parkinson, B.

    2003-06-01

    Large hydroelectric projects have been met with strong resistance from affected communities, particularly indigenous groups who have been displaced from their flooded communities following the damming of a river. The World Commission on Dams (WCD) was formed in 1998 to review the effectiveness of large dams and develop internationally acceptable guidelines and standards for large dams or hydro energy projects. The Canadian government, through the Canadian International Development Agency, was one of many governments to fund the WCD. However, the authors argue that despite the financial support, the Canadian government was absent from any effort to follow-up on the recommendations of the WCD. The seven strategic priorities in the decision making process include: (1) gaining public acceptance, (2) comprehensive option assessment of water, energy, food and development needs, (3) addressing existing dams to improve the benefits that can be derived from them, (4) sustaining livelihoods, (5) recognizing the entitlements and sharing benefits, (6) ensuring compliance, and (7) sharing rivers for peace, development and security. This report offers a means to assess planned or existing dams and presents a set of guidelines for good practices linked to the seven strategic priorities. Ten case studies from around the world were presented, including the Three Gorges Dam in China. 154 refs., 3 figs., 3 appendices.

  13. 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.

  14. 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...

  15. 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.

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

    Science.gov (United States)

    Austin, J H; Thorsen, M K

    1981-12-01

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

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1981-12-01

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

  19. Rehabilitation at Olympic Dam

    International Nuclear Information System (INIS)

    Rehabilitation work on areas denuded of vegetation during the exploration phase of the Olympic Dam project was used to test various methods for regeneration of vegetation cover in the arid zone. The test work carried out on drill pads and access tracks has indicated that, with adequate site preparation, natural regeneration is the most economical and effective method to ensure post-operational stability of the affected land-forms. An on-going monitoring regime, utilising a computer data base, has been set up to allow year-to-year comparison of rehabilitation effectiveness. The database also provides a catalogue of initial colonising plants and a measure of variations in species diversity with time

  20. Dam safety realization of waste and tailings dams in Finland; Paloturvallisuuden toteutuminen Suomen jaete- ja kaivospadoilla

    Energy Technology Data Exchange (ETDEWEB)

    Sivonen, M.; Frilander, R.

    2001-05-01

    The present situation of waste- and tailings dams in Finland has been determined in this study including the structural safety and environmental impacts caused by dam functioning and failure. The collection of dam safety information was done with the help of the dam safety files and the technical visits on the dam sites. In addition the questionings were send to the dam owners. All together 61 waste dams and 12 tailings dams were investigated in the project. The realization of dam safety has been evaluated by dam structures and by meeting the requirements for the dams. The impacts on health and the environment have been evaluated during the dam functioning and failure. Furthermore the dam safety realization has been evaluated by occurred problems, the dam monitoring and the documents relevant to dam safety. On account of the project results the recommendations have been made in order to improve dam safety. In the future the dam failures can be avoided if (1) the geotechnical and other instructions for the dams are obeyed in the dam design and construction and (2) the operation, the maintenance and the monitoring of the dams will follow the Dam Safety Code of Practice. (orig.)

  1. Public safety around dams guidelines

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, T. [Canadian Dam Association, Edmonton, AB (Canada)

    2010-07-01

    This presentation discussed Canadian and international initiatives for improving dam safety and described some of the drivers for the development of new Canadian Dam Association (CDA) public safety guidelines for dams. The CDA guidelines were divided into the following 3 principal sections: (1) managed system elements, (2) risk assessment and management, and (3) technical bulletins. Public and media responses to the drownings have called for improved safety guidelines. While the public remains unaware of the hazards of dams, public interaction with dams is increasing as a result of interest in extreme sports and perceived rights of access. Guidelines are needed for dam owners in order to provide due diligence. Various organizations in Canada are preparing technical and public safety dam guidelines. CDA guidelines have also been prepared for signage, booms and buoys, and audible and visual alerts bulletins. Working groups are also discussing recommended practices for spill procedures, spillways and the role of professional engineers in ensuring public safety. Methods of assessing risk were also reviewed. Managed system elements for risk assessment and public interactions were also discussed, and stepped control measures were presented. tabs., figs.

  2. 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.

  3. 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.

  4. 75 FR 49429 - Metal and Nonmetal Dams

    Science.gov (United States)

    2010-08-13

    ...Dam failures at metal and nonmetal mines have exposed miners to life-threatening hazards. The Mine Safety and Health Administration (MSHA) is reviewing its existing metal and nonmetal standards for dams. The Agency is concerned that some dams pose hazards because they are not designed, constructed, operated, and maintained to accepted dam safety practices. MSHA is considering approaches to......

  5. 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.

  6. Seismic stability analyses - embankment dams

    Energy Technology Data Exchange (ETDEWEB)

    Boudreau, Stephane; Boulanger, Pierre; Caron, Louis Philippe [BPR, Montreal, (Canada); Karray, Mourad [Sherbrooke University, Sherbrooke, (Canada)

    2010-07-01

    An understanding of the effect of earthquakes is necessary to the design of safe dams. A wide number of methods are currently used or being developed for analysing the dynamic slop stability of embankments/dams. This paper investigated the effects of the dynamic aspects (natural period, amplifications and intensity of seismic loading) in the analysis of small dams. A procedure was developed to evaluate the performance of pseudo-static analyses by comparison with fully dynamic analyses. Static, pseudo-static, and dynamic analyses were performed using finite elements and Mohr-Coulomb shear strength criteria. The overall safety factor (FS) was compared using the reduction factor concept. The study worked on two examples of small dams located at moderate and violent seismic regions in the province of Quebec. These examples illustrated the difference between pseudo-static and dynamic analyses. The study also investigated the values of the kh coefficient for Eastern Canada seismicity.

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

    OpenAIRE

    Nassar, Mohammad

    2014-01-01

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

  8. 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...

  9. 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.

  10. 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.

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

    NARCIS (Netherlands)

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

    2012-01-01

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

  12. 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.

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

    Science.gov (United States)

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

    2012-01-01

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

  14. Grouting Applications in Cindere Dam

    Directory of Open Access Journals (Sweden)

    Devrim ALKAYA

    2011-01-01

    Full Text Available Grouting is one of the most popular method to control the water leakage in fill dam constructions. With this regard this method is widely used in all the world. Geological and geotechnical properties of rock are important parameters affect the design of grouting. In this study, geotechnical properties of Cindere Dam's base rock and the grouting prosedure have been investigated with grouting pressure.

  15. Manual on small earth dams

    OpenAIRE

    Stephens, Tim

    2015-01-01

    "This publication fills a void of practical guidelines for the construction of small earth dams. It presents readers with sound, reliable and practical source material to improve dam siting and design capacity in rural areas, to introduce a beneficiary and gender sensitive approach and to enhance safety and competence in construction. A section also provides convenient guidance on costing, drafting tenders and awarding contracts. The manual is primarily aimed at technicians and others with kn...

  16. 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

  17. 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.

  18. 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.

  19. Seismic behavior of concrete filled steel tubular arch structures

    Institute of Scientific and Technical Information of China (English)

    Xiong Feng; Sashi K Kunnath; Liu Haowu

    2005-01-01

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

  20. Mission archéologique islamique

    Directory of Open Access Journals (Sweden)

    Claire Hardy-Guilbert

    1997-11-01

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

  1. Dam Safety. Distributed Strain Measurements for Embankment Dams - Field Tests at Ajaure Dam 2004-05

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, Sam [HydroResearch Sam Johansson AB, Stockholm (Sweden); Watley, Dan [Sensornet Ltd, London (United Kingdom)

    2005-09-01

    There is growing interest to measure strain in many civil structures such as dams, bridges and tunnels. Optical fibre sensors are increasingly used to measure both temperature and, strain in such constructions. Essential development of this application for dams has been made previously by Sensornet and HydroResearch, within three research projects funded by Elforsk AB. In September 2004, the first distributed measurement of strain in an embankment dam was undertaken using the Sensornet DTSS. The system allows the strain and temperature to be measured simultaneously and independently at all points along the fibre. The measurement was carried out at Vattenfall Vattenkraft's Ajaure dam in Sweden. The aim was to compare the measurements taken during September, at full reservoir level, with measurements to be taken at low reservoir level in May 2005. The measured difference of strain between the two measurements is small, indicating no significant localized movement of the dam. These initial measurements demonstrate the potential of distributed strain measurements. Whilst undertaking strain measurement at Ajaure, a series of tests were also performed to demonstrate the ability of the DTSS to determine the size of localized deflection in the dam which could be detected by distributed strain measurements. Similar tests were also repeated in the Sensornet Laboratory. Those tests have demonstrated that a deflection of the dam by just 5 mm will be detectable. The current sensitivity of the system is suitable for detecting very small localized changes of the dam structure. However, the sensitivity is set to improve with further development, providing enhanced temperature correction and hence much increased strain accuracy. Distributed optical sensing will be an essential tool for dam monitoring, providing location specific information which has not been available before. The distributed technology provides an excellent complement to conventional inclinometers. Further

  2. 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.

  3. Floods from tailings dam failures.

    Science.gov (United States)

    Rico, M; Benito, G; Díez-Herrero, A

    2008-06-15

    This paper compiles the available information on historic tailings dam failures with the purpose to establish simple correlations between tailings ponds geometric parameters (e.g., dam height, tailings volume) and the hydraulic characteristics of floods resulting from released tailings. Following the collapse of a mining waste dam, only a part of tailings and polluted water stored at the dam is released, and this outflow volume is difficult to estimate prior the incident. In this study, tailings' volume stored at the time of failure was shown to have a good correlation (r2=0.86) with the tailings outflow volume, and the volume of spilled tailings was correlated with its run-out distance (r2=0.57). An envelope curve was drawn encompassing the majority of data points indicating the potential maximum downstream distance affected by a tailings' spill. The application of the described regression equations for prediction purposes needs to be treated with caution and with support of on-site measurement and observations. However, they may provide a universal baseline approximation on tailing outflow characteristics (even if detailed dam information is unavailable), which is of a great importance for risk analysis purposes. PMID:18096316

  4. 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.

  5. Three Gorges Dam, China

    Science.gov (United States)

    2002-01-01

    This ASTER image shows a 60 km stretch of the Yangtze River in China, including the Xiling Gorge, the eastern of the three gorges. In the left part of the image is the construction site of the Three Gorges Dam, the world's largest.This image was acquired on July 20, 2000 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet.ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. Science team leader; Bjorn Eng of JPL is the project manager. The Terra mission is part of NASA's Earth Science Enterprise, a long-term research and technology program designed to examine Earth's land, oceans, atmosphere, ice and life as a total integrated system.The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.Size: 60 x 24 km (36 x 15 miles) Location: 30.6 deg. North lat., 111.2 deg. East long. Orientation: North at top Image Data: ASTER bands 1,2, and 3

  6. Three Gorges Dam Passes Test

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Floodwaters are released from the Three Gorges Dam on the Yangtze River in Yichang,central China’s Hubei Province,on July 20.The dam,China’s largest flood control project,acts as a buffer for the worst flood-ing in decades as it blocks more than 40 percent of upstream water.The peak influx into the Three Gorges Reservoir topped 70,000 cubic meters a second on July 20,the highest level since the dam was completed last year.The flow is still 30,000 cubic meters below its designed capacity.The discharge has been kept under 40,000 cubic meters a second to help flood-fighting efforts in downstream areas that have been plagued by weeks of heavy rainfalls.The Three Gorges Reservoir has a capacity of more than 20 billion cubic meters with a maximum water level of 175 meters.

  7. 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.

  8. Island Falls 'A' dam repair

    International Nuclear Information System (INIS)

    Repairs to the Island Falls 'A' Dam located on the Churchill River in northern Saskatchewan is described. The dam was built in 1928-1930. It had suffered extensive freeze thaw damage and some portions of the structure did not meet minimum safety standards. The paper emphasizes concrete repair methodology, the design and installation of high strength steel anchors for stability enhancement, increasing structural capacity, re-establishment of drainage and re-design of spillway operations. The extensive involvement with the local First Nations community, which was critical to the successful completion of the job is also discussed

  9. 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...

  10. 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...

  11. Report on the mining dams committee

    Energy Technology Data Exchange (ETDEWEB)

    Small, A.

    2010-04-01

    The Canadian Dam Association (CDA) committee is working with the Mining Association of Canada (MAC) tailings working group to ensure that technical issues related to the management and stewardship of tailings facilities are resolved. The Oilsands Dams Closure Group is now planning a workshop to discuss closure issues associated with the oilsands mining dams. The oilsands industry is currently constructing a number of large dams designed to contain contaminated solids and fluids. The dams will be required to last in perpetuity, and the closure group has been formed to consider what conditions will be required to maintain the dams in relation to regulatory oversight and inspections. The dams present an environmental challenge to the oilsands industry and may be of interest to many other mining industries who are required to retain dams forever.

  12. Simulation of Breach Outflow for Earthfill Dam

    International Nuclear Information System (INIS)

    Dams have been built for many reasons such as irrigation, hydropower, flood mitigation, and water supply to support development for the benefit of human. However, the huge amount of water stored behind the dam can seriously pose adverse impacts to the downstream community should it be released due to unwanted dam break event. To minimise the potential loss of lives and property damages, a workable Emergency Response Plan is required to be developed. As part of a responsible dam owner and operator, TNB initiated a study on dam breach modelling for Cameron Highlands Hydroelectric Scheme to simulate the potential dam breach for Jor Dam. Prediction of dam breach parameters using the empirical equations of Froehlich and Macdonal-Langridge-Monopolis formed the basis of the modelling, coupled with MIKE 11 software to obtain the breach outflow due to Probable Maximum Flood (PMF). This paper will therefore discuss the model setup, simulation procedure and comparison of the prediction with existing equations.

  13. Arch development with trans-force lingual appliances.

    Science.gov (United States)

    Clark, William J

    2005-01-01

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

  14. 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....

  15. 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... Cherokee, Fort Loudoun, Tellico, and Watts Bar Dams. The notice of availability (NOA) of the Final Environmental Impact Statement for Dam Safety Modifications at Cherokee, Fort Loudoun, Tellico, and Watts...

  16. 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.

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

    Science.gov (United States)

    Gardner, R B

    1979-04-01

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

  18. Comparison of arch forms between Turkish and North American

    OpenAIRE

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

    2016-01-01

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

  19. WinDAM C earthen embankment internal erosion analysis software

    Science.gov (United States)

    Two primary causes of dam failure are overtopping and internal erosion. For the purpose of evaluating dam safety for existing earthen embankment dams and proposed earthen embankment dams, Windows Dam Analysis Modules C (WinDAM C) software will simulate either internal erosion or erosion resulting f...

  20. 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...

  1. 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.)

  2. 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.

  3. Developmental feature of the lumbosacral vertebral arch in childhood

    International Nuclear Information System (INIS)

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

  4. Using resistivity measurements for dam safety evaluation at Enemossen tailings dam in southern Sweden

    OpenAIRE

    Sjödahl, Pontus; Dahlin, Torleif; Johansson, S.

    2005-01-01

    Internal erosion is a major reason for embankment dam failures. Resistivity measurements is an essentially non-destructive technique, which may have the possibility of detecting internal erosion processes and anomalous seepage at an early stage before the safety of the dam is at stake. This paper presents results from part of a dam safety investigation conducted at the Enemossen tailings dam in southern Sweden. Longitudinal resistivity sections, 2D measurements along the dam crest, provided a...

  5. Piezometer performance monitoring at Waterton Dam

    Energy Technology Data Exchange (ETDEWEB)

    Cullum-Kenyon, S.; Sobkowicz, J.C. [Thurber Engineering Ltd., Calgary, AB (Canada); Paz, S. [Alberta Environment, Edmonton, AB (Canada)

    2009-07-01

    In 2007, a dam safety review of the Waterton Dam, located in southern Alberta, was completed. The dam safety review included an evaluation of the instrumentation installed at the dam, and what this instrumentation showed about the performance of the structure. This paper described the review of the instrumentation and dam performance, with particular emphasis on a set of hydraulic piezometers installed in the core at the deepest section of the dam. The paper presented background information on the dam and outlined the instrumentation and performance monitoring. Piezometer types were discussed. Performance data for the hydraulic and pneumatic piezometers in the dam core were summarized along with observations for piezometers in the foundation, upstream portion of the core and in the middle of the core. It was concluded that the review of dam performance has identified a horizontal zone of likely higher permeability within the dam, coinciding with the upper portion of the first construction season of the dam. 5 refs., 1 tab., 13 figs.

  6. 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.

  7. Dam safety practice in Alberta for Alberta Environment owned water management dams

    Energy Technology Data Exchange (ETDEWEB)

    Acharya, Mohan; Wog, Karyn [Alberta environment, Edmonton, (Canada)

    2010-07-01

    Water management operations operates and maintains over 200 water management structures throughout Alberta. It includes around 30 extreme consequence, very high consequence and high consequence dams according to the Canadian Dam Association's (CDA) dam safety guidelines 2007. The safety of these structures is very important for the water management operations. This paper presented dam safety practise at water management operations dams. A historic perspective review of dam safety in Alberta was made. A framework of plant-implement-review-improve-report was developed and is currently used by the infrastructure support dam safety (ISDS) engineers. This dam safety work priority framework encourages an integrated decision making process and gives the dam safety team a tool for using and sharing information. This project made recommendations to rectify deficiencies, including with respect to priorities and timeframes, which are based on the severity of the issue, risk assessment and the consequences of failure.

  8. Proceedings of the 2010 Canadian Dam Association's public safety around dams workshop

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-01

    Nearly 30 people have drowned in dam-related incidents over the last 10 years in Canada. The Canadian public is now calling for improved safety guidelines. Public interaction with dams is increasing as a result of interest in extreme sports and perceived rights of access. However, many members of the public are not aware of the dangers posed by dams. This workshop provided a forum to discuss proposals for a draft publication of the Canadian Dam Association (CDA) guidelines for public safety and security around dams. Issues related to current legislation and liability were discussed. Methods of increasing public awareness of the hazards posed by dams included increased signage in dam locations, the use of audible and visual alert systems, and the use of booms and buoys. The responsibilities of dam owners in ensuring the safety of dams were also discussed. The conference featured 5 presentations, of which 2 have been catalogued separately for inclusion in this database. tabs., figs.

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

    Science.gov (United States)

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

    2016-10-01

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

  10. 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.

  11. EPRI dam safety workshop summary: Proceedings

    International Nuclear Information System (INIS)

    The Electric Power Research Institute (EPRI) has an extensive history of working with utilities, federal and state agencies, consultants, and other interests to conduct a number of workshops and studies to improve the safety of dams. Through these efforts, EPRI has developed a number of tools to assist dam owners, particularly EPRI members, in the evaluation and modification of dams. Although a considerable amount of progress has been made toward improving dam safety, there remain among the over 75,000 dams in the US a significant number of structures that require in-depth evaluation and possible modifications. At the same time, there are pressures from several directions to prioritize dam safety issues and find cost-effective solutions to problems because there seems to be an ever-decreasing amount of funds to address dam safety. In that regard, EPRI is sensitive to those cost considerations in a changing utility environment. Therefore, EPRI recently entered into discussions with utilities, regulatory agencies, federal agencies (dam owners), and others interested in dam safety issues. From those discussions, a number of research ideas were developed, which were distilled into three primary topics and several secondary topics of importance. The three primary areas of concern included: penstocks, tunnels, and gates; instrumentation and monitoring; and post-tensioned anchors. This report will provide a review of the workshop and insight on ideas for future dam safety R and D

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

    Science.gov (United States)

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

    2004-10-01

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

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

    Science.gov (United States)

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

    2005-12-01

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

  14. 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.

  15. 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.

  16. 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.

  17. 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)

  18. 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

  19. 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.

  20. 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.

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

    Science.gov (United States)

    Armellini, Debora; von Fraunhofer, J Anthony

    2004-12-01

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

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

    Science.gov (United States)

    Lui, T H

    2016-06-01

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

  3. Excitation of Arch and Suspension Bridges by Subwires

    Directory of Open Access Journals (Sweden)

    Noriaki Hiwatashi

    1993-01-01

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

  4. Excitation of Arch and Suspension Bridges by Subwires

    OpenAIRE

    Noriaki Hiwatashi; Yoji Mizuta; Yutaka Ishihara; Itio Hirai

    1993-01-01

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

  5. Reliability of earth dams on compound base

    OpenAIRE

    G.Ya. Bulatov; D.S. Gatanov

    2012-01-01

    This article deals with the design of earth dams (estimating filter strength, compressibility and permeability of soils, studing of the stress-strain state, etc.) The authors look through a new, not previously discussed task of reliability of groundwater dams in extreme conditions like an influence of new and additional loads in the form of intense deformation of elongation and the base curvature.The dependences that allow determining the permissible values of deformations of ground dams eart...

  6. Behavior of dams subjected to induced loads

    OpenAIRE

    Trebušak, Branka

    2014-01-01

    In the thesis, the influence of underwater explosion on safety of concrete gravity dams has been analysed. Moreover, a historical overwiew of various attacks on different dams and their failures has been made based on the available literature. A special attention has been given to the effects of shock wave caused by the explosion. A parametric study has been conducted in a computer program CADAM. The safety of concrete gravity dam Moste, which has been subjected to equivalent static load of t...

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

    OpenAIRE

    Deng-hong CHEN; Du, Cheng-bin

    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...

  8. 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.

  9. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Day, D.L.

    1985-04-01

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

  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. 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.

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

    OpenAIRE

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

    2014-01-01

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

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

    OpenAIRE

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

    2015-01-01

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

  15. Olympic Dam - the first decade

    International Nuclear Information System (INIS)

    Most aspects of the pre-production phase of the Olympic Dam Project, from commencement of exploration in May 1975 through to commitment to development in December 1985 are documented here. The discovery by Western Mining Corporation Ltd of copper mineralisation on Roxby Downs Station in July 1975 has led to one of the more intensive base-metal exploration programmes undertaken in Australia. Comprehensive exploration, evaluation and feasibility studies between 1975 and 1985 have delineated a probable 450 million tonnes of higher grade ore containing 2.5% copper, 0.8 kg/t uranium oxide, 0.6 g/t gold and 6.0 g/t silver. The total resource is estimated at 2 billion tonnes containing 1.6% copper, 0.6 kg/t uranium oxide, 0.6 g/t gold and 3.5 g/t silver. At 31 December 1985, over 540 km of surface and underground drilling had been completed, comprising over 700 surface drillholes totalling 234 km of core and 218 km of open-hole drilling, and about 900 underground diamond-drillholes totalling 90 km. The Whenan Shaft had been sunk to 500 m and driving on three levels totalled almost 10 km. More than one million tonnes of ore and mullock were raised during development. A pilot treatment plant commissioned on site produced concentrates, matte and blister copper, and ammonium diuranate. Following a technical study of the Olympic Dam Project, completed in March 1985, and a subsequent economic feasibility study, it was announced on 11 June 1985 that the initial project was considered to be commercially viable. On 8 December 1985, the joint venturers, Western Mining Corporation Holdings Ltd (51%) and the BP Group (49%), announced their commitment to the Project. An appendix lists the important events that occurred between January 1986 and December 1987 in bringing Olympic Dam to the production state. 26 refs., 17 figs., 5 tabs., ills

  16. Patriarchal Representations in Dam Street

    OpenAIRE

    Zhaohui Liu; Yushan Zhao

    2015-01-01

    An analysis of recessive and dominant patriarchies is critical to the understanding of Chinese women’s issues in Yu Li’s film Dam Street. Recessive patriarchy is a subtle form of male dominance; dominant patriarchy embodies the simple and direct form. Both traditional and new elements could be traced in the two types of characters. An investigation into the characters’ development is done through reading the scenes of the film in the Chinese cultural frames. The finding is that the nature of ...

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

    Science.gov (United States)

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

    2004-12-01

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

  18. 49 CFR 230.61 - Arch tubes, water bar tubes, circulators and thermic siphons.

    Science.gov (United States)

    2010-10-01

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

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    Lifescience Database Archive (English)

    Full Text Available Pol.Emb.05.AllAg.Maxillary_arch_junction mm9 RNA polymerase Embryo Maxillary arch jun...ction http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Pol.Emb.05.AllAg.Maxillary_arch_junction.bed ...

  20. File list: ALL.Emb.50.AllAg.Maxillary_arch_junction [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Emb.50.AllAg.Maxillary_arch_junction mm9 All antigens Embryo Maxillary arch jun...ction SRX699776 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/ALL.Emb.50.AllAg.Maxillary_arch_junction.bed ...

  1. File list: Pol.Emb.20.AllAg.Maxillary_arch_junction [Chip-atlas[Archive

    Lifescience Database Archive (English)

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

  2. Fragility Analysis of Concrete Gravity Dams

    Science.gov (United States)

    Tekie, Paulos B.; Ellingwood, Bruce R.

    2002-09-01

    Concrete gravity dams are an important part ofthe nation's infrastructure. Many dams have been in service for over 50 years, during which time important advances in the methodologies for evaluation of natural phenomena hazards have caused the design-basis events to be revised upwards, in some cases significantly. Many existing dams fail to meet these revised safety criteria and structural rehabilitation to meet newly revised criteria may be costly and difficult. A probabilistic safety analysis (PSA) provides a rational safety assessment and decision-making tool managing the various sources of uncertainty that may impact dam performance. Fragility analysis, which depicts fl%e uncertainty in the safety margin above specified hazard levels, is a fundamental tool in a PSA. This study presents a methodology for developing fragilities of concrete gravity dams to assess their performance against hydrologic and seismic hazards. Models of varying degree of complexity and sophistication were considered and compared. The methodology is illustrated using the Bluestone Dam on the New River in West Virginia, which was designed in the late 1930's. The hydrologic fragilities showed that the Eluestone Dam is unlikely to become unstable at the revised probable maximum flood (PMF), but it is likely that there will be significant cracking at the heel ofthe dam. On the other hand, the seismic fragility analysis indicated that sliding is likely, if the dam were to be subjected to a maximum credible earthquake (MCE). Moreover, there will likely be tensile cracking at the neck of the dam at this level of seismic excitation. Probabilities of relatively severe limit states appear to be only marginally affected by extremely rare events (e.g. the PMF and MCE). Moreover, the risks posed by the extreme floods and earthquakes were not balanced for the Bluestone Dam, with seismic hazard posing a relatively higher risk.

  3. Stabilizing the tailing dam at Hengyang Uranium mill

    International Nuclear Information System (INIS)

    The engineering measures combined with vegetation for stabilizing tailing dam at Hengyang unanium mill is described briefly. Improvements on dam safety, environment management and dam life time that have been achieved over the last 5 years are presented

  4. Double aortic arches, esophageal atresia and tracheal compression

    OpenAIRE

    Majid Yameen; Warade Monali; Aziz Zarina; Karthik G

    2009-01-01

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

  5. 3D Stretchable Arch Ribbon Array Fabricated via Grayscale Lithography

    Science.gov (United States)

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

    2016-06-01

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

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

    OpenAIRE

    O'Donovan, Danielle

    2001-01-01

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

  7. Dental arch diameters and relationships to oral habits.

    Science.gov (United States)

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

    2006-05-01

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

  8. 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.

  9. 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.

  10. 3D Stretchable Arch Ribbon Array Fabricated via Grayscale Lithography.

    Science.gov (United States)

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

    2016-01-01

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

  11. 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.

  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. 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.

  14. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Jaremko, D.

    2006-01-15

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

  16. CREATIVITY METHODS IN TEACHING THE ARCH-DESIGN STUDIO

    Directory of Open Access Journals (Sweden)

    EIGBEONAN Andrew B.

    2013-01-01

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

  17. Three-dimensional stiffness of the carpal arch.

    Science.gov (United States)

    Gabra, Joseph N; Li, Zong-Ming

    2016-01-01

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

  18. 7 CFR 1724.55 - Dam safety.

    Science.gov (United States)

    2010-01-01

    ... Guidelines for Dam Safety,”FEMA 93, June, 1979, published by the Federal Emergency Management Agency (FEMA...“Federal Guidelines for Dam Safety”may be obtained from the Federal Emergency Management Agency, Mitigation... Emergency Management Agency, Mitigation Directorate, PO Box 2012, Jessup, MD 20794....

  19. SEDIMENT MANAGEMENT IN FLOOD CONTROL DAMS

    OpenAIRE

    Pattanapanchai, Maneechit; Shah, Farhed A.; Annandale, George

    2002-01-01

    Reservoir sedimentation reduces economic value and longevity of flood control dams. Periodic sediment removal allows extension of reservoir life. An optimal control model is developed to evaluate alternative sediment management strategies for flood control dams. An illustrative empirical analysis shows that sustainable management is economically desirable for a wide range of parameter values.

  20. 75 FR 62024 - Metal and Nonmetal Dams

    Science.gov (United States)

    2010-10-07

    ... Safety and Health Administration 30 CFR Parts 56 and 57 RIN 1219-AB70 Metal and Nonmetal Dams AGENCY... an Advance Notice of Proposed Rulemaking (75 FR 49429) asking interested parties to comment on measures to assure that metal and nonmetal mine operators design, construct, operate and maintain dams in...

  1. 30 CFR 57.20010 - Retaining dams.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Retaining dams. 57.20010 Section 57.20010 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Miscellaneous § 57.20010 Retaining dams. If failure of a water or...

  2. Dams in transition; Talsperren im Wandel

    Energy Technology Data Exchange (ETDEWEB)

    Koengeter, Juergen

    2010-07-01

    From the past over the present till to the future dams may be regarded under mainfold points of view, each of which are subject to varied transitions. This article deals with the broad concerns of dams and the people involved with and within their environment. (orig.)

  3. 30 CFR 56.20010 - Retaining dams.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Retaining dams. 56.20010 Section 56.20010 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Miscellaneous § 56.20010 Retaining dams. If failure of a water or...

  4. 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

  5. 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.

  6. 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

  7. Seismic response of uplifting concrete gravity dams

    International Nuclear Information System (INIS)

    The foundation interaction effects on the seismic response of dam-foundation systems have generally been studied using the linear elastic finite element models. In reality, the foundation can not develop effective tensile stresses to a significant degree along the interface. A two-dimensional finite element model, in which nonlinear gap elements are used at the dam-foundation interface to determine the uplift response of concrete gravity dams subjected to seismic loads, is presented. Time domain analyses were performed for a wide range of modelling assumptions such as dam height, interface uplift pressure, interface mesh density, and earthquake input motions, that were systematically varied to find their influence on the seismic response. The nonlinear interface behavior generally reduces the seismic response of dam-foundation systems acting as a seismic isolation mechanism, and may increase the safety against sliding by reducing the base shear transmitted to the foundation. 4 refs., 5 figs., 6 tabs

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. The role of dams in development

    International Nuclear Information System (INIS)

    Although the amounts of water resources are enough for the entire world, the distribution of them in time and space shows uneven pattern. The water need is increasing with heavy industrial and agricultural requirements, while available water in the world remains as a fixed source. Economic growth, socio-cultural, and environmental developments are being realized following these changes. In order to achieve sustainable management of water resources, these changes have to be taken into consideration in water-related development projects. Demand for water is steadily increasing through out the world, even though the fresh water resources are limited and unevenly distributed, during the past three centuries, the amount of water withdrawn from fresh water resources has increased by a factor of 35, whereas world population by a factor 8. The engineering of dams, which provides regular water from reservoirs of dams to be used in case of demand pattern, is a vital part of the civilization. Dams have played a key rote in the development since the third millennium B C when the first great civilizations evolved on major rivers, such as Tigris-Euphrates, the Nile and the Indus. From these early times dams were built for flood control, water supply, irrigation and navigation. Dams also had been built to produce motive power and electricity since the industrial revolution. Development priorities changed, experience accumulated with the construction and operation of dams. Although the importance of water is well known in the human life and civilization around the world, still various groups argue that expected economic benefits are not being produced and that major environmental, economic and social costs are not being taken into account. By the end of 20th century, there were 45000 large dams in over 150 countries. According to the same classification there are 625 large dams in Turkey. All over the world, 50 % of the large dams were built mainly for irrigation. It is estimated

  15. Dam construction in salt rock

    International Nuclear Information System (INIS)

    Barriers are a major component of the satefy concept for the Gorleben repository. The construction and performance of dams are currently tested within the framework of a project carried out in the Asse salt mine. A measuring programme has been established to give evidence of the sealing capacities of a barrier consisting of an abatement, long-term sealing material, and a hydraulic sealing system. Tests are to be made to verify the barrier's performance for shorter of long time periods (up to about 500 years). The tests are assisted by computed models established for the project. The long-term safety aspects to be studied include such conditions as permeability changes due to mechanical impacts, circulation conditions at the roadside, and the serviceable life and efficiency of the sealing components. (DG)

  16. 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.

  17. 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.

  18. 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...

  19. Failure of Tapo Canyon Tailings Dam

    OpenAIRE

    Harder, Leslie F Jr; Stewart, Jonathan P.

    1996-01-01

    The failure of the Tapo Canyon tailings dam was one of the most striking failures of an earth structure to result from the January 17, 1994 Northridge, California earthquake. The failure involved a 60-m-wide breach of a tailings dam with a maximum height of 24 m, and 60 and 90 m downstream displacements of two sections of the dam. The failure resulted from liquefaction of the impounded tailings and possibly of the embankment materials. A significant volume of liquefied tailings passed through...

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

    OpenAIRE

    Qadir Bhatti, Abdul

    2009-01-01

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

  1. CREATIVITY METHODS IN TEACHING THE ARCH-DESIGN STUDIO

    OpenAIRE

    EIGBEONAN, Andrew B.

    2013-01-01

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

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

    OpenAIRE

    S. Sabouri

    2007-01-01

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

  3. Giant aortic arch aneurysm complicating Kawasaki′s disease

    OpenAIRE

    Kaouthar Hakim; Rafik Boussada; Lilia Chaker; Fatma Ouarda

    2014-01-01

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

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

    OpenAIRE

    Grublytė, Ieva; Surgailis, Donatas; Škarnulis, Andrius

    2015-01-01

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

  5. MODELING EXCHANGE RATES USING ARCH FAMILY OF MODELS

    Directory of Open Access Journals (Sweden)

    Ştefan Cristian CIUCU

    2016-06-01

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

  6. The Randomized Shortened Dental Arch Study: Tooth Loss

    OpenAIRE

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

    2010-01-01

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

  7. 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.

  8. 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.)

  9. 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.

  10. Establishment and implementation of a dam safety program

    International Nuclear Information System (INIS)

    The reasons for implementing dam safety programs are discussed, and a model for a dam safety program is outlined. A dam safety program should consist of regular inspections, reservoir monitoring, an emergency action plan, remedial work, registration permit reports, routine maintenance, and careful water supply management. Recommendations on initiating and implementing a dam safety program include: communication with the appropriate regulatory authority; communication with maintenance crews; communication with management; a well-rounded dam inspection team; the inclusion of maintenance items in dam modification projects; visual inspection of the dam; monitoring key indicators such as monuments and piezometer readings; and keeping current with the literature. 4 refs

  11. Stability analysis on a planned Mexican tailings dam

    OpenAIRE

    Törnqvist, Sofie; Lindquist, Amanda

    2016-01-01

    If mine waste materials are stored in dams, the dams are referred to as tailings dams. Tailings dam failures can lead to massive destruction in nearby areas because of the large amount of water and slurry tailings stored in the dams. Tailings dams are large constructions which therefore endure great stresses. If the stresses become higher than what the materials of the dam can tolerate there is a risk that the embankment will collapse. This master thesis is the result of a collaboration betwe...

  12. 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

  13. 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.

  14. 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].

  15. 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.

  16. Proceedings of the Canadian Dam Association workshop on public safety around dams

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    The Canadian Dam Association (CDA) issued dam safety guidelines in 1995. Since then, the guidelines have been widely used in Canada and elsewhere, and have become a standard in Canada where regulations do not exist. This workshop was a forum to begin the process of creating a draft publication of a new version of the CDA Dam Safety Guidelines that will incorporate issues of public safety and security around dams. The objectives of the workshop were to learn the current state of industry practice in terms of public safety around dams; input to the draft CDA guidelines; discuss the principles which will govern preparation of the guidelines; share experiences in public safety around dams; hear regulator's views on the issue of public safety around dams; and establish areas for further research and development. The presentations discussed a broad range of topics, including recent waterway incidents around dams; industry initiatives and benchmarking; occupier's liability and trespass; high risk behaviour near dams and power stations; risk assessment process for public safety; and the Federal Energy Regulatory Commission's (FERC's) hydropower public safety program. The workshop featured 18 presentations, of which 13 have been catalogued separately for inclusion in this database. tabs., figs.

  17. 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...

  18. 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...

  19. 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.)

  20. 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...

  1. 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...

  2. 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... embankments at four (Cherokee, Fort Loudoun, Tellico, and Watts Bar) dams. These measures included raising...

  3. 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

  4. Leibis/Lichte Dam in Germany

    Science.gov (United States)

    Kühnel, Markus

    In Thuringia the second highest dam of Germany is under construction (figure 1). The new Leibis/Lichte dam is a 370 m long and 102.5 m high gravity dam of concrete with straight axis. With the completion of the Leibis/Lichte dam in 2005 more than 300.000 inhabitants of the Eastern Regions of Thuringia will be supplied with high quality drinking water. The foundation rocks at the dam site are exclusively greyish-blue argillaceous schist, silt schist and cleaved fine sandstones from the Ordovician period (phycode schist). The main joint system consists of three differently orientated joints. Geomechanically of main interest is the shallow dipping bedding, especially in the left abutment because of its downhill dip. The other joints show a generally steep dip. Wide extending faults with thick mylonites or fractured zones, which could influence the foundation of the dam, do not exist within the dam site. The engineering geological field mapping of the foundation surface confirms the rock mass parameters. The excavation works are carried out in four different stages to avoid loosening of the foundation rock. Great care is taken to assure that the foundation rock is protected against weathering. Based on the results of preliminary investigations the foundation level was planned in a depth of 4 to14 m. The abutments of the dam correspond to the expectations. Predominantly the argillaceous rock shows a low permeability. The permeability is exclusively linked to faults respectively few large joints. In order to prevent seepage and to reduce the uplift pressure, a grout curtain in two rows is arranged with a depth of 5 to 44 metres.

  5. Beaver Dam Wash Instream Flow Assessment

    OpenAIRE

    United States Bureau of Land Management

    1998-01-01

    This report documents findings from an instream flow assessment conducted by the U.S. Bureau of Land Management (BLM) on Beaver Dam Wash in Mohave County, Arizona. The assessment, which focused on resources located at the mouth of Beaver Dam Wash from 1991 through 1994, provides a scientific basis for relating flowdependent resources to streamflow levels. Natural resource values, methods of data collection and analysis, and flow requirements are presented in this report.

  6. Stability and performance of older dams

    Energy Technology Data Exchange (ETDEWEB)

    Dharmawardene, W.; Herbig, A.; Morrison, J. [Alberta Environment, AB (Canada); Chan, D. [Alberta Univ., Edmonton, AB (Canada). Dept. of Civil and Environmental Engineering

    2003-07-01

    There are 1300 licensed dams in Alberta. Most were designed and constructed between the late 1940s and the early 1960s. As a rule, compacted earthfill in preglacial and interglacial valleys in southern Alberta was used to construct all dams of moderate height. At these dam sites, the foundations are of valley infill alluvial soils underlain by weak rocks. The best prevailing engineering practices at the time were used to design these dams. It included drilling, soil testing prior to and during construction, and some stability analyses. Despite these measures, a number of the dams built on soft clays suffered significant deformations and cracking of the embankment during construction. A re-examination of the stability of some of the older dams in Alberta, owned by the provincial department of the Environment, was undertaken six years ago using currently accepted design practices. Allowance was made in the new analyses for the presence of shear zones and fissures in the foundation soils, as well as softening caused by wetting. Despite many years of apparently satisfactory service, Factors of Safety that were marginal or deficient were discovered at many dams. The authors presented case histories of three older dams (North and South McGregor, and North Ridge, all located in southern Alberta) for which the long term Factors of Safety were marginal under normal loading. A number of criteria, such as deformation, stress strain curves of foundation materials and the consequence of failure were taken into consideration in assessing and confirming the requirement for repair before any structural modifications were undertaken. Some of the repairs that were carried out were also briefly described. 12 refs., 4 tabs., 5 figs.

  7. Tailings dams in the Republic of Macedonia

    OpenAIRE

    Krstev, Boris; Mirakovski, Dejan

    2001-01-01

    Flotation Tailing dams if not built and managed by all the norms and standards, can pose environmental bombs. They can be big polluters vicinity of surface and groundwater and the air. So, by land, water and air, these operating environment and the entire flora and fauna. Flotation reagents used in the technological process, and dissolved salts of heavy metals are usually present in waters discharged from Tailing dams. These waters, in addition to the remains of flotation reagents (xantates, ...

  8. Flotation tailing dams in Republic of Macedonia

    OpenAIRE

    Golomeov, Blagoj; Krstev, Boris; Golomeova, Mirjana; Kostadinov, Ljubisa

    2012-01-01

    The tailing dams are considered as potential ecological "bombs" if not constructed and managed according to the normatives and standards assigned for them. In certain cases they can be also contaminators of the environment, surface and ground waters, as well as the air. That means that through the land, water and air the tailing dams act on the environment and all flora and fauna. The flotation reagents used in the tehchnological process, as well and the resoluted salt of the heavy metals are...

  9. Risk assessment of tailings facility dam failure

    OpenAIRE

    Hadzi-Nikolova, Marija; Mirakovski, Dejan; Stefanova, Violeta

    2011-01-01

    This paper presents the consequences of tailings facility dam failure and therefore the needs for its risk assessment. Tailings are fine-grained wastes of the mining industry, output as slurries, due to mixing with water during mineral processing. Tailings dams vary a lot as it is affected by: tailings characteristics and mill output, site characteristics as: topography, hydrology, geology, groundwater, seismicity and available material and disposal methods. The talings which accumulat...

  10. 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)

  11. 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.

  12. Expectations of immortality: dam safety management into the next millennium

    International Nuclear Information System (INIS)

    Topics concerning the problems associated with older and aging dams are considered including: what can be done to extent the lifetime of an old dam, the decision to decommission a dam based on a value judgment that the risk of maintaining the dam is too great for society's acceptance, the possibility of change in the level of risk tolerance with time in a technological environment, traditional surveillance methods used by dam owners in the Y2K situation, and the unreality of dam immortality. Trends and means for preserving older dams for their owner's purposes are outlined, as well as their lifetime compared to that of the downstream systems they serve. Despite the fact that we live in a throwaway society, dam owners cannot just leave their dam asset when they are through with using it. Someone has to maintain the dam, or ensure that it is safely decommissioned when the owner is finished with it. On a worldwide scale the available pool of experienced dam engineers is shrinking. This problem needs to be addressed by a shift towards operating and dam safety management skills based on a firm awareness of dam design principles. A shift in society's expectations has occurred such that dam designers and owners must now recognize the impact a dam can have both on its natural and social environments. Because of the increasing emphasis on paying attention to the impacts of people's activities on the planet, engineers more than anyone else must have a significant influence in that direction. 9 refs

  13. Statical and dynamical soil-structure interaction between diaphragm wall and its surrounding soil in the embankment dam with diaphragm wall under soil core. Renzoku chichuheki wo yusuru firu dam no chichuheki to jiban tono seiteki doteki sogo sayo

    Energy Technology Data Exchange (ETDEWEB)

    Kanazawa, K.; Nishigori, T. (Electric Power Development Co. Ltd., Tokyo (Japan)); Watanabe, H. (Saitama University, Saitama (Japan). Faculty of Engineering); Takada, M. (Chiba Prefectural Government, Chiba (Japan))

    1992-12-15

    In case of applying the diaphragm cutoff wall to the foundation treatment of embankment dam to be constructed on the alluvial deposit, it is indispensable to take the seismic influence into consideration for the design. In the present paper, study was made of statical and dynamical soil-structure interaction between the diaphragm wall and its surrounding soil. Study through numerical analysis was also made of dam stability for the dams typified by Tadami's which was taken as an example. The influence of rigidity was particularly studied of diaphragm wall through comparison between the ordinary concrete (A) and bentonite concrete (B), and the dynamical characteristics were confirmed through in-situ vibration test. For example, the following was elucidated as a result of test: As for the state of stress at the time of embankment completion, the diaphragm wall which uses high rigidity A gives a strong stress concentration on its top and tends to simultaneously generate a weak point in stress distribution due to the arch action on the lateral surface near its top. However in case of using low rigidity B, it is considerably improved. 16 refs., 22 figs., 2 tabs.

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

    Science.gov (United States)

    Sachdeva, Shabina; Tripathi, Arvind; Kapoor, Pranav

    2014-09-01

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

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

    OpenAIRE

    Mohammad, Aljanakh; Koralakunte, Pavankumar Ravi

    2015-01-01

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

  16. 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.

  17. 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.

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

    Science.gov (United States)

    Amm, E W; Bou-Serhal, J P

    2003-12-01

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

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

    Science.gov (United States)

    Dholakia, Kartik D; Bhat, Shweta R

    2012-01-01

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

  20. 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).

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

    OpenAIRE

    O'Donovan, Danielle

    2005-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Rong Chen

    2013-01-01

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

  3. 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.

  4. Two ARCH Models and Their Limitations as Diffusion Processes

    Institute of Scientific and Technical Information of China (English)

    杨海波; 叶俊

    2002-01-01

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

  5. Ice interactions at a dam face

    Energy Technology Data Exchange (ETDEWEB)

    Morse, B.; Morse, J.; Beaulieu, P.; Pratt, Y. [Laval Univ., Quebec City, PQ (Canada). Dept. of Civil Engineering; Stander, E. [State Univ. of New York, Cobleskill College, Cobleskill, NY (United States). Dept. of Natural Sciences; Cote, A.; Tarras, A.; Noel, P. [Hydro-Quebec, Varennes, PQ (Canada). IREQ

    2009-07-01

    This paper reported on a joint research project between Laval University and Hydro-Quebec to study ice forces on dams in an effort to harmonize design criteria and develop mitigation strategies. This paper introduced the project and explored some of the preliminary results of the 2007-2008 field season. Ice displacement, ice stresses and ice forces on the LaGabelle dam were measured at several locations. The paper identified and discussed the complex relationships between data sets and discussed the spatial-temporal variability of the ice forces and its impact on design criteria. The project objective was to develop design criteria for ice forces on dams and to provide a scientific basis for interpreting and harmonizing existing recommended criteria. The methodology and site description were presented. It was concluded that the ice processes in a reservoir near a dam face subject to water fluctuations are quite complex. Therefore, in order to know the real average pressure on the dam, a significant amount of panels are required, having important implications for determining safe design values. 9 refs., 10 figs.

  6. Measurement of ice thrusts on dams

    Energy Technology Data Exchange (ETDEWEB)

    Taras, A.; Cote, A.; Noel, P.; Lupien, R. [Institut de Recherche d' Hydro-Quebec, Varennes, PQ (Canada); Morse, B.; Pratt, Y. [Laval Univ., Quebec City, PQ (Canada); Stander, E. [State Univ. of New York Cobleskill College, Cobleskill, NY (United States); Comfort, G. [Fleet Technologies, Ottawa, ON (Canada)

    2009-07-01

    Ice loads exerted on dams are not well understood. Measuring ice pressure is a challenge, especially when the ice environment is highly subject to creep. This paper discussed a program to evaluate ice load thrust on dams that was undertaken during the winter of 2007 to 2008 at La Gabelle and 2008 to 2009 at Beaumont and La Gabelle. The project involved measuring ice load thrust on the dam face in order to harmonize different design load criteria put forward by experts. The paper presented the preliminary results on the objectives of establishing maximum load levels and harmonizing ice load design criteria. Field program and instrumentation and the physical behaviour of ice were outlined. Ice pressure and ice load measurements were also discussed. It was concluded that the measurements near the dams yielded peak values of less than 150 kN/m, which was compatible with previous studies. Non-uniform distributions of the ice loads along the dam were observed, indicating that measurements at many points are needed in order to be meaningful. 10 refs.

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

    Science.gov (United States)

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

    2013-01-01

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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Micron narrowband adaptive optics imaging in the arches cluster

    CERN Document Server

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

    2001-01-01

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

  13. THE EVOLUTION OF PROTOPLANETARY DISKS IN THE ARCHES CLUSTER

    International Nuclear Information System (INIS)

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

  14. 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.

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

    Science.gov (United States)

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

    2014-03-01

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

  16. Probabilistic assessment of tailings dam stability

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, Tarek; Mitri, Hani [McGill University, Montreal, (Canada); Saad, Bassam [Parsons Brinckerhoof Inc., Dallas, (United States)

    2010-07-01

    There is a need for research on upstream tailings dams to better understand the causes of past failures and to provide the tools capable of operating such facilities reliably and safely. This paper presented the development of a method for determining tailings dam stability. The study proposed the use of the point estimate method (PEM) as a tool to account for the inherent uncertainty in tailings impoundment. The PEM is an alternative approach for calculating the statistical moments of the limit state function. The proposed approach is applied on a cross-section of an upstream tailings dam to evaluate its performance during staged construction using a 2-D nonlinear coupled finite element model. The results illustrated the benefits of the proposed approach. This was the first time that the PEM was applied to a tailings impoundment using the hydro-mechanical, fully coupled transient finite element modelling technique.

  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. Re-grouting of Maroon Dam foundation

    Energy Technology Data Exchange (ETDEWEB)

    Palassi, M. [Tehran Univ. (Iran, Islamic Republic of). Dept. of Civil Engineering; Sharghi, A. [JTMA Co., Tehran (Iran, Islamic Republic of)

    2003-07-01

    The Maroon dam, built on the Maroon River in the Khoozestan province (southwest) of Iran, has a height of 176 metres and a 1.2 billion cubic metre reservoir. It is one of the largest embankment dams in Iran. A number of unpredicted inflows of water into tunnels and other underground openings occurred during the first impoundment of the Maroon dam. Impoundment was halted and the reservoir was emptied to correct the problem. This paper reviews the measures that were implemented during the remediation process, and presented an evaluation of the effectiveness of the process. The foundation treatment involved placing concrete in the caverns, constructing a concrete lining, and extending the grout curtain. The grouting procedure was also described. The overall effectiveness of the concrete work and grouting resulted in a reduction in leakage from 8.5 cubic metres per second to a more acceptable 10 litres per second. 8 figs.

  19. The big issue: environment and large dams

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, Peter [Harvard Univ. (United States)

    1999-09-01

    Some of the environmental issues associated with large dams are discussed. Prior to commencement of construction of the Three Gorges dam in China in 1993, 50 years of planning and 20 years of environmental argument had taken place. The Chinese were conscious of the need to consider the environmental issues as a factor in attracting foreign investment for the world's biggest and most expensive dam. While the resettlement issues (1.2 M people were resettled) have dominated the current arguments, the other important issues are environment, economics and safety. Despite criticism from environmentalists, both at home and abroad, the Chinese went ahead with the project. With regard to resettlement, the Chinese appear to be much more considerate than some other countries in providing housing and agricultural land. Perhaps the main losses were suffered by cultural heritage sites and aquatic systems, rather than by the resettled population. (UK)

  20. 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.

  1. Seismic response of concrete gravity dam reinforced with FRP sheets on dam surface

    Directory of Open Access Journals (Sweden)

    Hong ZHONG

    2013-10-01

    Full Text Available This paper aims at exploring the effects of anti-seismic reinforcement with the fiber-reinforced polymer (FRP material bonded to the dam surface in dam engineering. Time-history analysis was performed to simulate the seismic failure process of a gravity dam that was assumed to be reinforced at the locations of slope discontinuity at the downstream surface, part of the upstream face, and the dam heel. A damage model considering the influence of concrete heterogeneity was used to model the nonlinearity of concrete. A bond-slip model was applied to the interface between FRP and concrete, and the reinforcement mechanism was analyzed through the bond stress and the stress in FRP. The results of the crack pattern, displacement, and acceleration of the reinforced dam were compared with those of the original one. It is shown that FRP, as a reinforcement material, postpones the occurrence of cracks and slows the crack propagation, and that cracks emanating from the upstream surface and downstream surface are not connected, meaning that the reinforced dam can retain water-impounding function when subjected to the earthquake. Anti-seismic reinforcement with FRP is therefore beneficial to improving the seismic resistant capability of concrete dams.

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

    Science.gov (United States)

    Tripathi, S.; Gekelman, W. N.

    2013-12-01

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

  3. Analysis of deformations of large earth dams

    Science.gov (United States)

    Szostak-Chrzanowski, Anna; Massiéra, Michel; Chrzanowski, Adam

    2007-09-01

    Safety of earth dams depends on the proper design, construction, and monitoring of actual behaviour during the construction and during the operation of the structure. The most critical factor in the assessment of the safety threshold value of any structure is the acceleration of its deformation. Therefore, the designed accuracy of monitoring surveys must fulfill requirements of detecting accelerations at critical locations of the investigated object. As an example, time dependant behavior of a large embankment dam during filling up the reservoir has been analyzed and verified by comparing monitoring results with the deterministic (prediction) model of the deformation. The geotechnical and geodetic monitoring besides providing a warning system in case of an abnormal behaviour of the dam, may be used as a tool for a verification of design parameters where geotechnical parameters are of the highest importance. Modeling of deformation of earth dams is a complex process in which one should consider the nonlinear behaviour of the construction material, interaction between the structure and the underlying foundation strata, influence of water load on the structure and on the foundation bedrock, and the effects of water saturation. Due to the uncertainty of the model parameters, careful monitoring of the dam and its surroundings are required in order to verify and enhance the model. In addition, with properly designed monitoring surveys, one may also determine the actual deformation mechanism. The finite element method may be useful tool in the proper design of the monitoring scheme by providing information on the locations and magnitude of the expected maximum displacements and velocites of movements. The discussed problems are illustrated by three types of earth dams located in California, U.S.A. and in Quebec, Canada.

  4. 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.

  5. 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.

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

    Science.gov (United States)

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

    2015-06-01

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

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

    Directory of Open Access Journals (Sweden)

    Shuren Wang

    2014-01-01

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

  8. 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.

  9. 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....

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

    Science.gov (United States)

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

    2013-11-01

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

  11. 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.

  12. Upgrade survives downturn: Bhumbiol dam in Thailand

    Energy Technology Data Exchange (ETDEWEB)

    Woeber, Georg [Hydro Refurbishment, Elin Energieversorgung (Austria)

    1999-10-01

    Refurbishing of the Bhumbiol dam in Thailand is described. The dam and power station were completed in 1964. The station has an installed capacity of 736MW, which is about one-third of the country's total hydro capacity. In 1980, the owners (The Electricity Generating Authority of Thailand) decided to renovate two units and contracts went to Elin Energieversorgung of Austria for generators and power plant equipment and to Voest Alpine Machinery and Construction for turbines and auxiliary equipment. In 1995 the same companies received orders for renovation of another two units. The remaining two units are also to be renovated despite the financial crisis in Southeast Asia. (UK)

  13. Geomechanical characteristics of the tailing dam "Topolnica"

    OpenAIRE

    Angelova, Aleksandra; Popovski, Risto; Panov, Zoran; Karanakova Stefanovska, Radmila; Delipetrev, Marjan

    2015-01-01

    The tailing dam "Topolnica“ is a storage type because it has a dual purpose, that is used for the disposal of tailings flotation in the space of a river bed and it accumulate fluid flow water from the river Topolnica which serving open pit mine with drinking water. First projected elevation was 610 m above sea level, it has long been exceeded and reached final height of 90 meters. In the last couple of years, when the elevation of the tailing dam arid approached to the final pr...

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

    OpenAIRE

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

    2015-01-01

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

  15. Stress and deformation analysis of 300 m-level high rockfill dams with arc and vertical cores%300m级弧形直心墙超高堆石坝应力变形分析

    Institute of Scientific and Technical Information of China (English)

    褚福永; 朱俊高; 张富有; 李永红

    2011-01-01

    对某300m级超高直心墙堆石坝及作为比较方案的弧形直心墙堆石坝进行了三维有限元应力变形计算.对2种坝型在蓄水期心墙的应力、变形进行了比较分析,结果表明:蓄水期,弧形心墙堆石坝比直心墙堆石坝的水平位移和沉降略小;弧形心墙坝的心墙拱效应较弱,其抗水力劈裂能力优于直心墙堆石坝;弧形心墙堆石坝坝肩处的应力水平小于直心墙堆石坝的相应值,减少了坝肩处心墙拉坏或剪坏的可能性.%The stress and deformation of a high rockfill dam with vertical core and with arc core is investigated by using three-dimensional finite element method. The stress and deformation of the two kinds of dams in the period of water storage is analyzed. The results show that the horizontal displacement and vertical displacement of the dam with arc core is slightly smaller than that of the rockfill dam with vertical core after the waterstorage. The arch effect of the dam with arc core is relatively weaker,and its ability of resisting hydraulic fracturing is stronger than that of the dam with vertical core. The stress level of the arc core dam at the abutment is smaller than that of the vertical core dam, and this reduces the possibility of shear failure and tensile failure at the zone of abutment.

  16. 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:...

  17. 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...

  18. 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.

  19. 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.

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

    Gillis, J Andrew; Hall, Brian K

    2016-04-15

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

  2. 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.

  3. Same River Twice: Restoration Politics, Water Policy, and Dam Removal

    OpenAIRE

    Brewitt, Peter K.

    2014-01-01

    Dam removal is a new and rapidly growing phenomenon that is reshaping watersheds across the United States; nearly 600 dams were removed from American rivers 1999-2012. Dam removal restores natural flows of water, material, and wildlife upstream, downstream, and out across the floodplain. Despite this massive restorative impact, it is politically controversial, reshaping familiar landscapes and challenging traditional economies and the communities that depended upon them. American dams are agi...

  4. 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.

  5. Construction of tailing dumps dams by using modern materials

    OpenAIRE

    Kostadinov, Ljubisa; Fidancev, Boris; Krstev, Boris; Golomeova, Mirjana; Golomeov, Blagoj

    2013-01-01

    During the construction of tailing dumps dams, modern materials can be used, which materials will improve the stability of dams and ensure high level of environmental protection. At tailing dumps where dams are built upstream or central it is possible the peripheral parts to be constructed by using geotubes. Thus improves the stability of the dam, prevents erosion and protects the air and surrounding area from fugitive emission of flotation sand with air currents. Also, to protect the ...

  6. Implications of dam obstruction for global freshwater fish diversity

    OpenAIRE

    Reidy Liermann, Catherine; Nilsson, Christer; Robertson, James; Ng, Rebecca

    2012-01-01

    Dams are obstructing rivers worldwide, impairing habitat and migration opportunities for many freshwater fish species; however, global data linking dam and fish distributions have been limited. Here, we quantify dam obstruction at the biogeographic scale of freshwater ecoregion, which provides the spatial framework necessary to assess the risk of fish species loss due to dams and allows us to identify both ecoregions and genera at risk. Nearly 50% of the 397 assessed freshwater ecoregions are...

  7. Design and Construction of Dams, Reservoirs, and Balancing Lakes

    International Nuclear Information System (INIS)

    The general data presented in sections two and three gives an idea of the extreme diversity of the millions of very large or very small dams worldwide. Dam design and construction methods for the most usual types of large dams are presented and justified in section four. The possibility and usefulness of building as many dams in the 21. century as have been built in the 20. is analyzed in section six. (author)

  8. Engineering with advanced materials for tailing dam designing

    OpenAIRE

    Kostadinov, Ljubisa; Krstev, Boris; Golomeov, Blagoj; Golomeova, Mirjana; Ilievski, Darko

    2012-01-01

    Tailing dam accidents hapened in the past serve as "alarm" for application of advanced methods and techniques at designing of tailing dams. The designing of advanced tailing dam nowdays is very current topic, due to the fact that designing would resolve very important issues for environmental protection. Advanced materials (geosyntetics) are used at process of construction in order the tailing dam to be constructed and to perform according to the advanced world standards. By applying the geos...

  9. 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.

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

    Science.gov (United States)

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

    2015-09-01

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

  11. 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.

  12. 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...

  13. 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)

  14. File list: InP.Emb.50.AllAg.Maxillary_arch_junction [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Emb.50.AllAg.Maxillary_arch_junction mm9 Input control Embryo Maxillary arch jun...ction http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/InP.Emb.50.AllAg.Maxillary_arch_junction.bed ...

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

    Lifescience Database Archive (English)

    Full Text Available NoD.Emb.05.AllAg.Maxillary_arch_junction mm9 No description Embryo Maxillary arch jun...ction http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/NoD.Emb.05.AllAg.Maxillary_arch_junction.bed ...

  16. File list: InP.Emb.10.AllAg.Maxillary_arch_junction [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Emb.10.AllAg.Maxillary_arch_junction mm9 Input control Embryo Maxillary arch jun...ction http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/InP.Emb.10.AllAg.Maxillary_arch_junction.bed ...

  17. File list: NoD.Emb.50.AllAg.Maxillary_arch_junction [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Emb.50.AllAg.Maxillary_arch_junction mm9 No description Embryo Maxillary arch jun...ction http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/NoD.Emb.50.AllAg.Maxillary_arch_junction.bed ...

  18. File list: NoD.Emb.10.AllAg.Maxillary_arch_junction [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Emb.10.AllAg.Maxillary_arch_junction mm9 No description Embryo Maxillary arch jun...ction http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/NoD.Emb.10.AllAg.Maxillary_arch_junction.bed ...

  19. File list: InP.Emb.05.AllAg.Maxillary_arch_junction [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Emb.05.AllAg.Maxillary_arch_junction mm9 Input control Embryo Maxillary arch jun...ction http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/InP.Emb.05.AllAg.Maxillary_arch_junction.bed ...

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

    Lifescience Database Archive (English)

    Full Text Available NoD.Emb.20.AllAg.Maxillary_arch_junction mm9 No description Embryo Maxillary arch jun...ction http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/NoD.Emb.20.AllAg.Maxillary_arch_junction.bed ...

  1. File list: InP.Emb.20.AllAg.Maxillary_arch_junction [Chip-atlas[Archive

    Lifescience Database Archive (English)

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

  2. 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.

  3. 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.

  4. 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.)

  5. 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.

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

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  7. The Evolution of Protoplanetary Discs in the Arches Cluster

    CERN Document Server

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

    2012-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Sumalatha S

    2016-05-01

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

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

    Directory of Open Access Journals (Sweden)

    Yang Yu-Jen

    2008-05-01

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

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

    Science.gov (United States)

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

    2010-08-01

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

  11. Experimental Research on the Dam-Break Mechanisms of the Jiadanwan Landslide Dam Triggered by the Wenchuan Earthquake in China

    Directory of Open Access Journals (Sweden)

    Fu-gang Xu

    2013-01-01

    Full Text Available 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.

  12. 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

  13. Expectations of immortality: dam safety management into the next millennium

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, M.D. [Tonkin and Taylor International Ltd., Auckland, (New Zealand)

    1999-07-01

    Topics concerning the problems associated with older and aging dams are considered including: what can be done to extent the lifetime of an old dam, the decision to decommission a dam based on a value judgment that the risk of maintaining the dam is too great for society's acceptance, the possibility of change in the level of risk tolerance with time in a technological environment, traditional surveillance methods used by dam owners in the Y2K situation, and the unreality of dam immortality. Trends and means for preserving older dams for their owner's purposes are outlined, as well as their lifetime compared to that of the downstream systems they serve. Despite the fact that we live in a throwaway society, dam owners cannot just leave their dam asset when they are through with using it. Someone has to maintain the dam, or ensure that it is safely decommissioned when the owner is finished with it. On a worldwide scale the available pool of experienced dam engineers is shrinking. This problem needs to be addressed by a shift towards operating and dam safety management skills based on a firm awareness of dam design principles. A shift in society's expectations has occurred such that dam designers and owners must now recognize the impact a dam can have both on its natural and social environments. Because of the increasing emphasis on paying attention to the impacts of people's activities on the planet, engineers more than anyone else must have a significant influence in that direction. 9 refs.

  14. Dam risk reduction study for a number of large tailings dams in Ontario

    Energy Technology Data Exchange (ETDEWEB)

    Verma, N. [AMEC Earth and Environmental Ltd., Mississauga, ON (Canada); Small, A. [AMEC Earth and Environmental Ltd., Fredericton, NB (Canada); Martin, T. [AMEC Earth and Environmental, Burnaby, BC (Canada); Cacciotti, D. [AMEC Earth and Environmental Ltd., Sudbury, ON (Canada); Ross, T. [Vale Inco Ltd., Sudbury, ON (Canada)

    2009-07-01

    This paper discussed a risk reduction study conducted for 10 large tailings dams located at a central tailings facility in Ontario. Located near large industrial and urban developments, the tailings dams were built using an upstream method of construction that did not involve beach compaction or the provision of under-drainage. The study provided a historical background for the dam and presented results from investigations and instrumentation data. The methods used to develop the dam configurations were discussed, and remedial measures and risk assessment measures used on the dams were reviewed. The aim of the study was to address key sources of risk, which include the presence of high pore pressures and hydraulic gradients; the potential for liquefaction; slope instability; and the potential for overtopping. A borehole investigation was conducted and piezocone probes were used to obtain continuous data and determine soil and groundwater conditions. The study identified that the lower portion of the dam slopes were of concern. Erosion gullies could lead to larger scale failures, and elevated pore pressures could lead to the risk of seepage breakouts. It was concluded that remedial measures are now being conducted to ensure slope stability. 6 refs., 1 tab., 6 figs.

  15. Proceeding of the public safety around dams conference

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    The Canadian Dam Association hosted the Public Safety Around Dams workshop in which presentations were given in the morning to describe the different measures and methods implemented by the Ontario Ministry of Natural Resources, Ontario Power Generation and others to improve safety around dams. In the afternoon, the participants toured the Auburn and Lakefield dams and facilities to view the infrastructures and equipment. A roundtable discussion concluded the day. Following this workshop, a Public Safety Around Dams group was created on the social network site, LinkedIn. This conference featured 6 presentations, 3 of which have been catalogued separately for inclusion in this database.

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

    Science.gov (United States)

    Gómez-Fragoso, Julieta; Heriberto Torres-Sierra

    2016-01-01

    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

  18. 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

  19. 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.

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

    Science.gov (United States)

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

    2009-12-01

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

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

    Directory of Open Access Journals (Sweden)

    Declan Sweeney, BSc (Hon

    2016-09-01

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

  2. Rehabilitation of an 80 year old Ambursen dam

    International Nuclear Information System (INIS)

    The Abitibi-Price Inc. hydroelectric facility at Bishop's Falls, NF, as built comprised an earth dam, a hollow concrete Ambursen type dam, and intake works at the powerhouse, as the main retaining structures. On January 13, 1983, an unprecedented flood occurred in the region which completely destroyed the earth dam connecting the powerhouse building to the riverbank of the town of Bishop's Falls. Major items of remedial work included a new earth dam and a new gated spillway. The flood did not result in any serious damage to the Ambursen dam, but exposure of the dam to the elements did result in stress which required rehabilitation. The favourable performance of the dam through a long service life in a northern Canadian climatic setting was a significant factor in the decision that the structure could be used without serious modification for at least 50 years. The evaluation of the dam, together with the distress experienced as a result of the flood and the remedial action applied are described as a case history. On the basis of condition and stability analysis, it was considered that repairs consisting of a new lining on the upstream side, grouting of deformation related cracking in the interior of the dam, and shotcrete treatment to the exterior of the downstream side, would give the dam a long service life. These remedial actions were applied, and the performance of the dam to date has met design expectations. 26 refs., 10 figs

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. Earthquake Hazard for Aswan High Dam Area

    Science.gov (United States)

    Ismail, Awad

    2016-04-01

    Earthquake activity and seismic hazard analysis are important components of the seismic aspects for very essential structures such as major dams. The Aswan High Dam (AHD) created the second man-made reservoir in the world (Lake Nasser) and is constructed near urban areas pose a high-risk potential for downstream life and property. The Dam area is one of the seismically active regions in Egypt and is occupied with several cross faults, which are dominant in the east-west and north-south. Epicenters were found to cluster around active faults in the northern part of Lake and AHD location. The space-time distribution and the relation of the seismicity with the lake water level fluctuations were studied. The Aswan seismicity separates into shallow and deep seismic zones, between 0 and 14 and 14 and 30 km, respectively. These two seismic zones behave differently over time, as indicated by the seismicity rate, lateral extent, b-value, and spatial clustering. It is characterized by earthquake swarm sequences showing activation of the clustering-events over time and space. The effect of the North African drought (1982 to present) is clearly seen in the reservoir water level. As it decreased and left the most active fault segments uncovered, the shallow activity was found to be more sensitive to rapid discharging than to the filling. This study indicates that geology, topography, lineations in seismicity, offsets in the faults, changes in fault trends and focal mechanisms are closely related. No relation was found between earthquake activity and both-ground water table fluctuations and water temperatures measured in wells located around the Kalabsha area. The peak ground acceleration is estimated in the dam site based on strong ground motion simulation. This seismic hazard analyses have indicated that AHD is stable with the present seismicity. The earthquake epicenters have recently took place approximately 5 km west of the AHD structure. This suggests that AHD dam must be

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

    OpenAIRE

    Sanjna Nayar; Aruna; Santhosh MR; Wasim Manzoor

    2015-01-01

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

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

    OpenAIRE

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

    2015-01-01

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

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

    Science.gov (United States)

    Yan, Huajun; Zhang, Shuangjie; Gao, Ying

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

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

    OpenAIRE

    Meldo Mahniza; Retno Hayati; Sri Harini

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Ivor M D′Souza

    2015-01-01

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

  14. 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.

  15. 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.

  16. Modeling of channel erosion downstream spillway dams

    Directory of Open Access Journals (Sweden)

    M.A. Mikhalev

    2013-03-01

    Full Text Available The channel erosion downstream spillway dams in non-cohesive materials has been analyzed from the viewpoint of methods of similarity and dimension theory. The obtained criterion equation connects the maximum depth of the local erosion with its determining parameters: length of concrete lining of bed in the down water of the spillway dam; Froude number at the contracted cross section; Archimedes and Reynolds criterions; submergence factor of hydraulic jump. The problem may be formulated as follows: the geometric size of the structure, kinematics and dynamics of the flows in the model are similar to that in the prototype. Conditions under which the characteristic depth of the local erosion in the model would be recomputed into the prototype, like any geometric size, are being discussed.

  17. Vung Tau - Co Gong dam, Vietnam

    OpenAIRE

    Dekens, B.; Meerdink, L.; G.J. Meijer; Sirks, E.; Vliet, R. van

    2011-01-01

    The area around Ho Chi Minh City (HCMC) faces flooding and salt intrusion problems. Flooding problems are caused by intensive rainfall in the city, high river discharges and high tides on sea. Dr. Hoc, the vice-minister of MARD (Vietnamese Ministry of Agriculture and Rural Development) proposed to construct a hydraulic structure downstream of HCMC. This will solve both the flooding and siltation problem. A possibility is to construct a dam between Vung Tau and Go Cong. This solution has been ...

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

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

    Directory of Open Access Journals (Sweden)

    Dong Yongxiang

    2009-03-01

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

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

    OpenAIRE

    O'Donovan, Danielle

    2001-01-01

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

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

    OpenAIRE

    O'Donovan, Danielle

    2004-01-01

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

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

    Science.gov (United States)

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

    2013-05-01

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

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

    OpenAIRE

    Saidi, Youssef; Zakoian, Jean-Michel

    2006-01-01

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

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

    OpenAIRE

    Sachdeva, Shabina; Tripathi, Arvind; Kapoor, Pranav

    2013-01-01

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

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

    OpenAIRE

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

    2012-01-01

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

  10. 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.

  11. 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.

  12. 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.

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

    OpenAIRE

    Joseph L. McCauley

    2008-01-01

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

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

    OpenAIRE

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

    2013-01-01

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

  15. 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.

  16. 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.

  17. Automatic dam concrete placing system; Dam concrete dasetsu sagyo no jidoka system

    Energy Technology Data Exchange (ETDEWEB)

    Yoneda, Y.; Hori, Y.; Nakayama, T.; Yoshihara, K.; Hironaka, T. [Okumura Corp., Osaka (Japan)

    1994-11-15

    An automatic concrete placing system was developed for concrete dam construction. This system consists of the following five subsystems: a wireless data transmission system, an automatic dam concrete mixing system, a consistency determination system, an automatic dam concrete loading and transporting system, and a remote concrete bucket opening and closing system. The system includes the following features: mixing amount by mixing ratio and mixing intervals can be instructed from a concrete placing site by using a wireless handy terminal; concrete is mixed automatically in a batcher plant; a transfer car is started, and concrete is charged into a bucket automatically; the mixed concrete is determined of its properties automatically; labor cost can be reduced, the work efficiency improved, and the safety enhanced; and the system introduction has resulted in unattended operation from the aggregate draw-out to a bunker line, manpower saving of five persons, and reduction in cycle time by 10%. 11 figs., 2 tabs.

  18. 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

  19. 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.

  20. 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...

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

    Science.gov (United States)

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

    2012-01-01

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

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2016-07-01

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

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

    Science.gov (United States)

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

    2016-06-01

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

  5. 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.

  6. 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.

  7. Stability of the dam at the Sillamaee tailings pond

    International Nuclear Information System (INIS)

    The tailings pond at Sillamaee is contained by a dam located 30 to 50 meters from the waters of the Baltic Sea. The tailings pond was begun in the 1950s, at which time the height of the dam was 12 m. It has been increased since then to 25 m. The apparently realtively unplanned buildup of the dam and lack of maintenance have led to a decrease in the stability of the dam. In its present conditions, the dam of the tailings pond is less stable than is recommended by international practice. Estonian, Norwegian, Swedish, and Finnish specialists have investigated various aspects of the dam's stability. This paper summarizes their findings and makes recommendations for further work

  8. The challenges of safety and stability of Iranian old dams

    Energy Technology Data Exchange (ETDEWEB)

    Ghaderi, Sadi; Mohamadi, Farhad [Golpayegan Dam, Golpayegan, (Iran, Islamic Republic of); Noorbakhsh, Seyed Mahdi [University of Science and Technology, Tehran, (Iran, Islamic Republic of)

    2010-07-01

    Fourteen dams over 30 years old are operating in Iran. These dams have important roles in flood control, hydroelectric power generation and water supply. Due to several factors, such as the lack of maintenance, repairs and qualified personnel , these dams represent a risk to public safety and are not able to operate. This paper provided a review of the status of old dams, operating for more than 50 years, in Iran. The history of each dam was investigated. The study identified key issues such as: operation, maintenance and repair, regular and accurate inspections and rehabilitation. It was also recommended that guidelines be developed to give a better understanding of these old dams. It was also proposed that a rehabilitation and reconstruction fund be created. Finally, training of new expert personnel through training courses and education programs was proposed.

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

    Institute of Scientific and Technical Information of China (English)

    WU; ZhongRu; SU; HuaiZhi; GUO; HaiQing

    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.

  10. 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

  11. Predicting surfacing internal erosion in moraine core dams

    OpenAIRE

    Rönnqvist, Hans

    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...

  12. The Changing Political Dynamics of Dam Building on the Mekong

    OpenAIRE

    Philip Hirsch

    2010-01-01

    This paper explores political dynamics surrounding dam building in the Mekong river basin, prior to, and following, the World Commission on Dams (WCD). Since the 1950s, dam building in the Mekong river basin has been enmeshed in a complex and shifting geopolitical and eco-political landscape. The broad geopolitical sweep of US hegemony, Cold War, regional rapprochement and the rise of China has been superimposed on eco-political shifts between modernist belief in progress as mastery over natu...

  13. Political Structure and Dam Conflicts: Comparing Cases in Southeast Asia

    OpenAIRE

    Ang, Ming Chee; Swain, Ashok

    2004-01-01

    This paper argues that different political structures use different conflict management mechanisms to manage opposition to large hydro projects. Conflicts over the Pak Mun Dam, Thailand (a liberal democracy), and the Bakun Dam, Malaysia (a semi-authoritarian state), are the cases selected for comparison. The export oriented, fast industrialization process brought rapid development in these two countries. Large-scale water development projects, particularly big dams, have been c...

  14. Experimental investigation of dynamic pressure loads during dam break

    CERN Document Server

    Lobovský, Libor; Castellana, Filippo; Mas-Soler, Jordi; Souto-Iglesias, Antonio

    2013-01-01

    The objectives of this work are to revisit the experimental measurements on dam break flow over a dry horizontal bed and to provide a detailed insight into the dynamics of the dam break wave impacting a vertical wall downstream the dam, with emphasis on the pressure loads. The measured data are statistically analyzed and critically discussed. As a result, an extensive set of data for validation of computational tools is provided.

  15. Geo-Seismic Environmental Aspects Affecting Tailings Dams Failures

    OpenAIRE

    J. M. Mayoral; Romo, M. P.

    2008-01-01

    Seismic performance evaluations of tailings dams are essential for characterizing the geo-environmental risks posed by these earthen structures, which should include the geotechnical hazards implied by slope instability failure, free board loss and the potential release of contaminants. The observed damage is more important when liquefaction occurs on the dam body and foundation, which often leads to cracking, settlements, tilting and general distortion of dam geometry. Analyses based on limi...

  16. Detection of Water Leaks in Beni-Haroun Dam (Algeria)

    International Nuclear Information System (INIS)

    The main objective of this work was to detect water leakage origin combining conventional, tracing and isotope techniques. The investigation was performed by a research team from the 'Algiers Nuclear Research Centre' in collaboration with engineers from the 'National Agency for Dams'. The chemical and isotopic results have shown no influence of dam water on the water sampled at the piezometers and drains that are present in the close neighbourhood of the dam. However, the water flowing at drain D15 has exhibited the nearest quality to that dam. Dye tracing has shown a water circulation through complex pathways for the left bank. (author)

  17. 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.

  18. MNR's role in public safety around dams

    Energy Technology Data Exchange (ETDEWEB)

    Keyes, Jennifer [Ministry of Natural Resources, Peterborough, ON (Canada)

    2011-07-01

    The Ministry of Natural Resources (MNR) is the largest dam owner in Ontario with around 400 dams located all across the province. MNR works to exercise stewardship of Ontario's water resources in a context of public safety, employee safety and environmental awarenes. This presentation shows the different measures MNR implemented to reduce risks. Warning signs, safety booms, barrel buoys and pedestrian fencing have been installed around dams to alert the public to possible dangers. In addition, MNR employees receive training in how to inspect dams for safety concerns, how to identify problems which could result in hazards to the public and how to work safely.

  19. 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) ...

  20. Environmental impacts of small dams on agriculture and ground water development: a case study of Khan pur Dam, Pakistan

    International Nuclear Information System (INIS)

    The water scarcity issues are increasing through out the world. Pakistan is also facing water crises and its water demands are increasing every day. During this research it is investigated that small dams are playing an important role for the sustainability of groundwater and agriculture. The main objective of this study was to assess the environmental impacts of small dam on agricultural and ground water. Proper planning and management of small dams may improve the sustainable agriculture in Pakistan. It is also concluded that small dams are significantly contributing towards economy, environment, local climate, recreational activities and crop production. Small dams can also be utilized for the production of electricity at local level. On the other hand, water management issues can be resolved by the involvement of local farmer's associations. Water losses through seepage, unlined channels and old irrigation methods are most critical in developing world. Considering the overall positive environmental impacts, construction of small dams must be promoted. (author)

  1. 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.

  2. 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.

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

    DEFF Research Database (Denmark)

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

    2008-01-01

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

  4. Hydropower potential of municipal water supply dams in Turkey. A case study in Ulutan Dam

    Energy Technology Data Exchange (ETDEWEB)

    Kucukali, Serhat [Civil Engineering Department, Zonguldak Karaelmas University, Incivez 67100, Zonguldak (Turkey)

    2010-11-15

    This paper aims to analyze the hydropower potential of municipal water supply dams in Turkey. The facility is in favor with the energy policy of Turkish Government and European Union. In the study, the design head of the power plant was selected as the average water level of the reservoir and the discharge was calculated from the annual water supply of the dam. It has been estimated that the existing 45 municipal water supply dams of Turkey have an electric energy potential of 173 GWh/year, corresponding to about 24,000,000 Euro/year economic benefit. The financing of these facilities can be provided from international funding institutions. For a case study, Zonguldak Ulutan Dam and its water treatment plant have been investigated in detail. The current electricity consumption of the water treatment plant is 4,500,000 kWh/year and the facility provides 35,000 m{sup 3}/day water to 6 settlements. The installation of a hydropower plant on the mentioned water treatment plant will cut the electric consumption by 24%. The proposed project has a payback period of 1.4 years and it can produce clean and feasible energy. (author)

  5. Hydropower potential of municipal water supply dams in Turkey: A case study in Ulutan Dam

    Energy Technology Data Exchange (ETDEWEB)

    Kucukali, Serhat, E-mail: kucukali78@hotmail.co

    2010-11-15

    This paper aims to analyze the hydropower potential of municipal water supply dams in Turkey. The facility is in favor with the energy policy of Turkish Government and European Union. In the study, the design head of the power plant was selected as the average water level of the reservoir and the discharge was calculated from the annual water supply of the dam. It has been estimated that the existing 45 municipal water supply dams of Turkey have an electric energy potential of 173 GWh/year, corresponding to about 24,000,000 Euro/year economic benefit. The financing of these facilities can be provided from international funding institutions. For a case study, Zonguldak Ulutan Dam and its water treatment plant have been investigated in detail. The current electricity consumption of the water treatment plant is 4,500,000 kWh/year and the facility provides 35,000 m{sup 3}/day water to 6 settlements. The installation of a hydropower plant on the mentioned water treatment plant will cut the electric consumption by 24%. The proposed project has a payback period of 1.4 years and it can produce clean and feasible energy.

  6. 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

  7. 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.

  8. MUD BANK SLIDING IN A DAM RESERVOIR

    Institute of Scientific and Technical Information of China (English)

    A.ALEXIS; D.MAROT; P.THOMAS

    2001-01-01

    Modernization and maintenance of a dam often require emptying the reservoir, a process that can cause mud bank instabilities and environmental disturbances. In order to address the problem of mud bank collapse characterization, a study is conducted in partnership with the Laboratoire National d'Hydraulique (LNH), a subsidiary of Electricité de France (EDF). This paper presents a geotechnical modeling of submerged and emergent mud bank stability and a comparison of the model results with the measurements carried out throughout the whole reservoir.

  9. The environment of the Olympic Dam project

    International Nuclear Information System (INIS)

    The Olympic Dam uranium/copper/gold project at Roxby Downs, South Australia, has a harsh environment with high summer temperatures, low rainfall and poor quality soils. There are no natural water courses. The vegetation is dominated by annual grasses in summer and wildflowers in winter. Red kangaroos are the most commonly sighted native mammals. The Fat-tailed Dunnart a nocturnal carniverous marsupial, is found. Eighty three bird species have been recorded. Reptiles are numerous and one amphibian occurs. A vermin eradication program aimed at rabbit control is conducted. ills

  10. Hovercraft drill probes Saraji tailings dam

    Energy Technology Data Exchange (ETDEWEB)

    1991-09-01

    In early operations at BHP-Utah's Saraji Mine in central Queensland, quantities of coking coal were pumped into the tailings dam because the preparation plant's flotation circuit was unable to handle ultra-fines. A reverse circulating drilling rig mounted on a hovercraft was used to recover 22 samples (representing 9 metres of tailings from 11 x 8 x 0.09 metre cores) in an investigation into whether the tailings can now be treated economically. 1 fig.

  11. Assessment of the Possible Extent of Loss of Life (LOL) Downstream of Large Dams due to Dam Failure Flooding

    OpenAIRE

    Saqib Ehsan; Walter Marx

    2014-01-01

    High flooding downstream of a dam could cause severe damages to the people and property. The most important damage is the loss of life which does not have any substitute. In this study, the extent of loss of life (LOL) downstream of a large dam due to dam failure has been focused. The LOL extent has been considered in terms of downstream distance. For systematic hydraulic analysis, the Jhelum river valley, about 329 km long downstream of Mangla dam in Pakistan has been taken into consideratio...

  12. The evolution of gravel bed channels after dam removal: Case study of the Anaconda and Union City Dam removals

    Science.gov (United States)

    Wildman, Laura A. S.; MacBroom, James G.

    2005-10-01

    The Anaconda and Union City Dams on the Naugatuck River in Connecticut were removed in February and October 1999. A detailed study of the sites prior to removal was undertaken including sediment testing and predictions of upstream channel formation post-dam removal. The 3.35-m-high timber crib/rock fill spillway of the Anaconda Dam partially breached during a storm prior to the dam's scheduled removal allowing a portion of the impounded sediment to move down through the river system. This event changed the removal plans and the remainder of the spillway was removed under an emergency order in the course of 4 days. The Union City Dam, a 2.44-m-high timber crib/rock fill dam capped with concrete and stone, was removed on schedule. A portion of the impounded sediment was removed by mechanical means during the deconstruction of the structure. The evolution of the two upstream channels post-project provided unique challenges and valuable insights as to what kind of channel transition can be expected in gravel bed river systems after a low head dam has been removed. This paper describes the initial engineering analysis and design, the subsequent removal of the two dams, and compares observations on the transition of the upstream channels following dam removal to the initial engineering predictions and other models. The relatively steep gravel bed channels evolved in a predictable manner, except where anthropogenic barriers (sanitary sewer, rock weir) interrupted.

  13. The World Commission on Dams + 10: Revisiting the Large Dam Controversy

    Directory of Open Access Journals (Sweden)

    Deborah Moore

    2010-06-01

    Full Text Available The World Commission on Dams (WCD was an experiment in multi-stakeholder dialogue and global governance concerned with a subject area – large dams – that was fraught with conflict and controversy. The WCD Report, Dams and Development: A New Framework for Decision-Making, was published in 2000 and accompanied by hopes that broad-based agreements would be forged on how to better manage water and energy development. Ten years later, this special issue of Water Alternatives revisits the WCD and its impacts, exploring the question: Is the WCD still relevant? The editorial team and the Guest Editors of this special issue of Water Alternatives have selected a range of 20 papers, 6 viewpoints, and 4 book reviews that help to illustrate the evolution in the dams debate. The goal of this special issue is to examine the influence and the impacts of the WCD on the dam enterprise, in general, and on the policies and practices of key stakeholders and institutions, and on the development outcomes for affected communities and environments, in particular. In this introduction, the Guest Editors provide an overview of the special issue, exploring the new drivers of dam development that have emerged during the last decade, including climate change and new financiers of dams, and describing the themes emerging from this diverse set of papers and viewpoints. This special issue demonstrates the need for a renewed multi-stakeholder dialogue at multiple levels. This would not be a redo of the WCD, but rather a rekindling and redesigning of processes and forums where mutual understanding, information-sharing, and norm-setting can occur. One of the most promising developments of the last decade is the further demonstration, in case studies described here, that true partnership amongst key stakeholders can produce transformative resource-sharing agreements, showing that many of the WCD recommendations around negotiated decision making are working in practice. We hope

  14. 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

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

    OpenAIRE

    Monzavi A.; Farhang Gh R

    2000-01-01

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

  16. 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.

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

    OpenAIRE

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

    2011-01-01

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

  18. Gypsum-karst problems in constructing dams in the USA

    Science.gov (United States)

    Johnson, Kenneth S.

    2008-01-01

    Gypsum is a highly soluble rock and is dissolved readily to form caves, sinkholes, disappearing streams, and other karst features that typically are also present in limestones and dolomites. Gypsum karst is widespread in the USA and has caused problems at several sites where dams were built, or where dam construction was considered. Gypsum karst is present (at least locally) in most areas where gypsum crops out, or is less than 30-60 m below the land surface. These karst features can compromise on the ability of a dam to hold water in a reservoir, and can even cause collapse of a dam. Gypsum karst in the abutments or foundation of a dam can allow water to pass through, around, or under a dam, and solution channels can enlarge quickly, once water starts flowing through such a karst system. The common procedure for controlling gypsum karst beneath the dam is a deep cut-off trench, backfilled with impermeable material, or a close-spaced grout curtain that hopefully will fill all cavities. In Oklahoma, the proposed Upper Mangum Dam was abandoned before construction, because of extensive gypsum karst in the abutments and impoundment area. Catastrophic failure of the Quail Creek Dike in southwest Utah in 1989 was due to flow of water through an undetected karstified gypsum unit beneath the earth-fill embankment. The dike was rebuilt, at a cost of US 12 million, with construction of a cut-off trench 600 m long and 25 m deep. Other dams in the USA with severe gypsum-karst leakage problems in recent years are Horsetooth and Carter Lake Dams, in Colorado, and Anchor Dam, in Wyoming.

  19. 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.

  20. Gypsum-karst problems in constructing dams in the USA

    Science.gov (United States)

    Johnson, K.S.

    2008-01-01

    Gypsum is a highly soluble rock and is dissolved readily to form caves, sinkholes, disappearing streams, and other karst features that typically are also present in limestones and dolomites. Gypsum karst is widespread in the USA and has caused problems at several sites where dams were built, or where dam construction was considered. Gypsum karst is present (at least locally) in most areas where gypsum crops out, or is less than 30-60 m below the land surface. These karst features can compromise on the ability of a dam to hold water in a reservoir, and can even cause collapse of a dam. Gypsum karst in the abutments or foundation of a dam can allow water to pass through, around, or under a dam, and solution channels can enlarge quickly, once water starts flowing through such a karst system. The common procedure for controlling gypsum karst beneath the dam is a deep cut-off trench, backfilled with impermeable material, or a close-spaced grout curtain that hopefully will fill all cavities. In Oklahoma, the proposed Upper Mangum Dam was abandoned before construction, because of extensive gypsum karst in the abutments and impoundment area. Catastrophic failure of the Quail Creek Dike in southwest Utah in 1989 was due to flow of water through an undetected karstified gypsum unit beneath the earth-fill embankment. The dike was rebuilt, at a cost of US $12 million, with construction of a cut-off trench 600 m long and 25 m deep. Other dams in the USA with severe gypsum-karst leakage problems in recent years are Horsetooth and Carter Lake Dams, in Colorado, and Anchor Dam, in Wyoming. ?? 2007 Springer-Verlag.