WorldWideScience

Sample records for arch dams including

  1. Grouting of karstic arch dam foundation

    Energy Technology Data Exchange (ETDEWEB)

    Young, J.; Rigbey, S. [Acres International, Niagara Falls, ON (Canada)

    2002-07-01

    A 200 m high arch dam and a 2000 MW underground power house complex is under development in the Middle East. The project is located in a highly seismic area in rugged, mountainous terrain. The arch dam is constructed on good quality limestone and dolomitic limestone rock mass, but it contains several zones of disturbed or sheared rock. The basement rock is slightly karstic with hydraulic conductivities in the order of 100 Lugeons. In order to get a satisfactory foundation surface for the dam, it will be necessary to excavate extensively and backfill with concrete. Because of the presence of many clay infilled cavities and fractures, geotechnicians are considering the installation of a multiple row grout curtain to a depth of 150 m below the dam foundation to ensure adequate seepage and uplift parameters when the reservoir is impounded. Initial grouting water pressure test results suggested that the grouting and drainage curtain should be extended to the left abutment beyond the current design. However, when horizontal slide models of the dam abutment were developed using the finite element program SEEPW, it was shown that there is no benefit to extending the length of grout curtains unless they are tied to an area of much lower hydraulic conductivity much deeper in the abutment. 1 tab., 5 figs.

  2. Mechanism Research of Arch Dam Abutment Forces during Overload

    Directory of Open Access Journals (Sweden)

    Yu Xia

    2015-01-01

    Full Text Available This paper presents research on the abutment forces of a double-curvature arch dam during overload based on numerical calculation results obtained through finite element method by Ansys. Results show that, with an increase in elevation, the abutment forces and bending moment of the arch dam increase first and then decrease from the bottom to the top of the dam. Abutment forces and bending moment reach their maximum at the middle or middle-down portion of the dam. The distributions of abutment forces and moment do not change during overload. The magnitude of each arch layer’s forces and moment increases linearly during overload. This result indicates that each arch layer transmits bearing loads to the rocks of the left and right banks steadily. This research explains the operating mechanism of an arch dam under normal and overload conditions. It provides a simple method to calculate the distribution of forces Fx and Fy and a new method to calculate the overload factor of an arch dam through the estimation of arch layers based on the redistribution characteristic of arch abutment forces.

  3. Numerical Analysis on Temperature Rise of a Concrete Arch Dam after Sealing Based on Measured Data

    Directory of Open Access Journals (Sweden)

    Qingbin Li

    2014-01-01

    Full Text Available The thermal boundary conditions in the construction and operation phases of a concrete arch dam are always complex. After sealing, differences between the arch dam temperature and its sealing temperature can cause compressive or tensile stresses. Based on measured temperature of an arch dam located in China, a temperature rise phenomenon (TRP is found in the after-sealed regions of the arch dam. By mining and analyzing the temperature data of various monitoring apparatus embedded in the arch dam, higher environment temperature is considered to be the main cause for the occurrence of the TRP. Mathematical methods for complex thermal boundary conditions, including external boundary conditions and internal heat source conditions, are proposed in this paper. A finite element model is implemented with the concern of the construction phase and operation phase of the arch dam. Results confirm good agreement with the measured temperature and verify the conjecture that the TRP occurs mainly because the external temperature of the arch dam is higher than its sealing temperature.

  4. Uncertainty Instability Risk Analysis of High Concrete Arch Dam Abutments

    Directory of Open Access Journals (Sweden)

    Xin Cao

    2017-01-01

    Full Text Available The uncertainties associated with concrete arch dams rise with the increased height of dams. Given the uncertainties associated with influencing factors, the stability of high arch dam abutments as a fuzzy random event was studied. In addition, given the randomness and fuzziness of calculation parameters as well as the failure criterion, hazard point and hazard surface uncertainty instability risk ratio models were proposed for high arch dam abutments on the basis of credibility theory. The uncertainty instability failure criterion was derived through the analysis of the progressive instability failure process on the basis of Shannon’s entropy theory. The uncertainties associated with influencing factors were quantized by probability or possibility distribution assignments. Gaussian random theory was used to generate random realizations for influence factors with spatial variability. The uncertainty stability analysis method was proposed by combining the finite element analysis and the limit equilibrium method. The instability risk ratio was calculated using the Monte Carlo simulation method and fuzzy random postprocessing. Results corroborate that the modeling approach is sound and that the calculation method is feasible.

  5. Simulation analysis of temperature control on RCC arch dam of hydropower station

    Science.gov (United States)

    XIA, Shi-fa

    2017-12-01

    The temperature analysis of roller compacted concrete (RCC) dam plays an important role in their design and construction. Based on three-dimensional finite element method, in the computation of temperature field, many cases are included, such as air temperature, elevated temperature by cement hydration heat, concrete temperature during placing, the influence of water in the reservoir, and boundary temperature. According to the corresponding parameters of RCC arch dam, the analysis of temperature field and stress field during the period of construction and operation is performed. The study demonstrates that detailed thermal stress analysis should be performed for RCC dams to provide a basis to minimize and control the occurrence of thermal cracking.

  6. Reliability of Arch dams subject to concrete swelling

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, J.M.; Silva, H.S.; Pinho, S. de [Laboratorio Nacional de Engenharia Civil (LNEC), Lisboa (Portugal)] [and others

    1995-12-31

    In this report, results of several studies are presented. The main aim of those studies was to assess the reliability of the three arch dams, in which swelling occurred due to alkali- aggregate reactions in various stages of development and having different effects on their reliability: the Cahora-Bassa dam, in Mozambique, where swelling accumulated up to the moment are very moderate and their development is apparently homogeneous; Santa-Luzia dam, in Portugal, where accumulated swelling have already considerable magnitude, nevertheless, important fissuration has not been observed up to the moment due to the homogeneous development of the swelling process; Alto-Ceira dam, also in Portugal, where accumulated swelling have also considerable magnitude but with a heterogeneous development, causing in conjunction with thermal variations important fissuration. Mention is made of mineralogical, chemical and petrographic analyses carried out for identification of the nature of reactions developed in each case and the back-analysis and other technics used in the assessment of the magnitude and distribution of swelling. Results are presented of measurement tests of the ultrasonic pulse velocity, used both in the assessment of alterations in the physical properties of concretes and in the determination of the depth of fissuration. Results are also presented of tests for characterisation of the rheology of integral concrete. Lastly, considerations are made about the reliability of the works on the basis of studies and the results of analyses of the state of stress, performed by means of the finite element method, by assuming for either visco-elastic or visco-elastic-plastic behaviour.

  7. 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.

  8. The development and use of geomechanical models for use in the raising of the Thirsk arch dam, Summerland, BC

    Energy Technology Data Exchange (ETDEWEB)

    Schlotfeldt, P.; Palleske, C. [Golder Associates Ltd., Squamish, BC (Canada)

    2009-07-01

    The Thirsk Dam and spillway on the Trout River in Summerland, British Columbia were completed in 1941. The dam was recently upgraded to increase total storage capacity and to refurbish the ageing infrastructure to comply with more stringent safety requirements. The upgrades included raising the arch dam by 5.3 metres; constructing new anchored thrust blocks on each abutment; constructing a new 190 m long concrete gravity spillway dam with a maximum height of 14 m; constructing a new earth-fill saddle dam; constructing 7 anchored foundation plinths; and adding a new concrete skin to the downstream face to increase the thickness of the arch. This upgrade increased the storage capacity by 96 per cent and provided adequate support to meet current dam safety regulations. In order to complete the upgrades, it was necessary to develop an understanding of the geotechnical parameters for the site for use in the analysis and design of anchorage, reinforcement and foundations of the raised structures. This paper described how the geological model was first developed and how it was applied during the design of the arch and spillway dams. The geological model was modified for local anomalies and unforeseen rock mass conditions. The paper also described the methods used to characterize the foundation rock mass and estimate rock mass strength and deformability properties. The models provided a three-dimensional understanding of potential failure mechanisms. 9 refs., 1 tab., 6 figs.

  9. A coupled FE and scaled boundary FE-approach for the earthquake response analysis of arch dam-reservoir-foundation system

    International Nuclear Information System (INIS)

    Wang Yi; Lin Gao; Hu Zhiqiang

    2010-01-01

    For efficient and accurate modelling of arch dam-reservoir-foundation system a coupled Finite Element method (FEM) and Scaled Boundary Finite Element method (SBFEM) is developed. Both the dam-foundation interaction and the dam-reservoir interaction including the effect of reservoir boundary absorption are taken into account. The arch dam is modelled by FEM, while the reservoir domain and the unbounded foundation are modelled by SBFEM. In order to make comparison with the results available in the literature, the Morrow Point arch dam is selected for numerical analysis. The analyses are carried out in the frequency domain, and then the time-domain response of the dam-reservoir-foundation system is obtained by Inverse Fourier Transform.

  10. 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.

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

    Science.gov (United States)

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

    2014-01-01

    The effect of solar radiation on thermal distribution in thin high arch dams is investigated. The differential equation governing thermal behavior of mass concrete in three-dimensional space is solved applying appropriate boundary conditions. Solar radiation is implemented considering the dam face direction relative to the sun, the slop relative to horizon, the region cloud cover, and the surrounding topography. It has been observed that solar radiation changes the surface temperature drastically and leads to nonuniform temperature distribution. Solar radiation effects should be considered in thermal transient analysis of thin arch dams. PMID:24695817

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

    Science.gov (United States)

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

    2014-01-01

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

  13. Grouting of the cracks in the Arch 5-6 Daniel Johnson dam

    International Nuclear Information System (INIS)

    Lariviere, R.; Routhier, L.; Roy, V.; Saleh, K.; Tremblay, S.

    1999-01-01

    The Daniel-Johnson dam is located 800 km northeast of Montreal, PQ, and is 1314 m in length and 214 m high. Just after completion of dam construction different types of cracks started to appear on the upstream and downstream faces. During and after the construction of the dam, numerous cracks and joints were grouted in order to reduce water infiltration. In some cases, as a result of high injection pressures and inaccurate methods, the injections provoked the propagation of the existing cracks or the initiation of new ones. Because of this situation and to determine the contribution of injection to dam safety, in 1985, Hydro-Quebec applied a moratorium on all future injection work on the dam. Research work was initiated in 1986 in the areas of grouting materials, methods, equipment and behavioral analysis to establish a safe method for the injection of the cracks. A committee was formed in 1993 with members from various groups, in order to: carry out extensive behavioral analysis of the Arch 5-6 dam, carry out an investigation program in order to determine the cause of the increase of the water infiltration, undertake a structural analysis program in order to evaluate the impact of an injection on the safety of the dam, and identify the proper method and injection products to use. In 1997, as a result of the progress of the structural analysis studies and the injection research project, a decision was made to proceed with the injection of the dam. A description is included of the results of the investigation, recommendations and results of the injection research project, as well as some details of the grouting campaign carried out in January 1999. On the whole, a better knowledge was acquired of the structure, of the plunging cracks and the behaviour of the dam during the injection. In the field of injection methods, materials and equipment, research work was invaluable when it came to the injection of micro-fine cracks in concrete dams. 5 refs., 8 figs

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-12-15

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

  15. Cracking Behavior of a Concrete Arch Dam with Weak Upper Abutment

    Directory of Open Access Journals (Sweden)

    Lei Xu

    2017-01-01

    Full Text Available The cracking behavior and failure mode of a 78 m high concrete double-curvature arch dam with weak upper abutment are investigated through performing cracking analysis. The mechanical behavior of concrete is simulated using a smeared crack model, in which a combination of the compression yield surface and the crack detection surface with a damaged elasticity concept is employed to describe the failure of concrete. The arch dam with practical mechanical properties of the upper and lower abutments is firstly studied with emphasis on its cracking behavior during overloading. Then, a comprehensive sensitivity analysis is carried out to investigate the influence of the ratio of the mechanical properties of upper abutment to those of lower abutment on dam failure with prime attention placed on the failure mode. Simulation results indicate the adopted smeared crack model is well-suited to the crack analysis of concrete arch dam. It is shown that cracking is localized around the interface between upper and lower abutments, which leads to a fast crack growth in the through-thickness direction of dam and finally causes the dam failure. Furthermore, the sensitivity analysis presents three types of failure modes corresponding to different ratio value, wherein Modes II and III should be avoided since the weak upper abutment plays a predominant role in the cracking and failure of concrete arch dam.

  16. User's Guide: Arch Dam Stress Analysis System (ADSAS)

    National Research Council Canada - National Science Library

    1997-01-01

    .... ADSAS assumes linear elastic behavior for the entire dam, i.e. the dam is assumed to support the computed tensile stresses within the concrete mass and across the monolith joints without cracking or opening the joints...

  17. Application of parallel computing to seismic damage process simulation of an arch dam

    International Nuclear Information System (INIS)

    Zhong Hong; Lin Gao; Li Jianbo

    2010-01-01

    The simulation of damage process of high arch dam subjected to strong earthquake shocks is significant to the evaluation of its performance and seismic safety, considering the catastrophic effect of dam failure. However, such numerical simulation requires rigorous computational capacity. Conventional serial computing falls short of that and parallel computing is a fairly promising solution to this problem. The parallel finite element code PDPAD was developed for the damage prediction of arch dams utilizing the damage model with inheterogeneity of concrete considered. Developed with programming language Fortran, the code uses a master/slave mode for programming, domain decomposition method for allocation of tasks, MPI (Message Passing Interface) for communication and solvers from AZTEC library for solution of large-scale equations. Speedup test showed that the performance of PDPAD was quite satisfactory. The code was employed to study the damage process of a being-built arch dam on a 4-node PC Cluster, with more than one million degrees of freedom considered. The obtained damage mode was quite similar to that of shaking table test, indicating that the proposed procedure and parallel code PDPAD has a good potential in simulating seismic damage mode of arch dams. With the rapidly growing need for massive computation emerged from engineering problems, parallel computing will find more and more applications in pertinent areas.

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  19. 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.

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

    Directory of Open Access Journals (Sweden)

    D. J. Vicente

    2017-01-01

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

  2. The effects of rock joint geometrical parameters on safety of concrete arch dam abutments

    Energy Technology Data Exchange (ETDEWEB)

    Yazdani, S.; Yazdani, M.; Joorabchi, A.E. [Tarbiat Modares Univ., Tehran (Iran, Islamic Republic of)

    2007-07-01

    The International Commission on Large Dams (ICOLD) has stated that foundation failure is the primary cause of dam failure following overtopping. As such, concrete arch dams require strong and stiff abutments. The failure of jointed rock mass at abutments is one of the key mechanisms that may lead to uncontrolled leakage. For that reason, this study investigated the affect of the joint geometrical parameters on the stability of the concrete arch dam abutments. The study also considered the role of joints on the behaviour mechanism of rock mass because it is governed by mechanical and hydraulic properties. The orientation of joints was considered since kinematic conditions are needed for a block to move. The hydromechanical influence of joint apertures on the stability of the foundation was also investigated through nonlinear analyses of different joint orientations and apertures on a hypothetical jointed abutment. Dam abutment safety was estimated by finding the values of maximum sliding and maximum opening and determining the water flow along discontinuities. The values of these 3 indices were derived for different orientations of joints. It was concluded that abutment safety was highly dependent on the geometrical characteristics of joints. 8 refs., 1 tab., 6 figs.

  3. Multi-objective optimization of an arch dam shape under static loads using an evolutionary game method

    Science.gov (United States)

    Meng, Rui; Cheong, Kang Hao; Bao, Wei; Wong, Kelvin Kian Loong; Wang, Lu; Xie, Neng-gang

    2018-06-01

    This article attempts to evaluate the safety and economic performance of an arch dam under the action of static loads. The geometric description of a crown cantilever section and the horizontal arch ring is presented. A three-objective optimization model of arch dam shape is established based on the arch dam volume, maximum principal tensile stress and total strain energy. The evolutionary game method is then applied to obtain the optimal solution. In the evolutionary game technique, a novel and more efficient exploration method of the game players' strategy space, named the 'sorting partition method under the threshold limit', is presented, with the game profit functions constructed according to both competitive and cooperative behaviour. By way of example, three optimization goals have all shown improvements over the initial solutions. In particular, the evolutionary game method has potentially faster convergence. This demonstrates the preliminary proof of principle of the evolutionary game method.

  4. 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.

  5. Dams

    Data.gov (United States)

    Vermont Center for Geographic Information — This dataset �is generated from from the Vermont Dam Inventory (VDI). The VDI is managed by the VT DEC's Dam Safety and Hydrology Section and contains information...

  6. 78 FR 17099 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago...

    Science.gov (United States)

    2013-03-20

    ...-AA00 Safety Zone, Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago... the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago... Guard will enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including...

  7. 78 FR 49684 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2013-08-15

    ...-AA00 Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago... the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago... the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago...

  8. 77 FR 20295 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago...

    Science.gov (United States)

    2012-04-04

    ... Zone, Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago Sanitary and Ship...; Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago Sanitary and Ship Canal... enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including Des Plaines...

  9. 78 FR 65874 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2013-11-04

    ...-AA00 Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago... the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago... Guard will enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including...

  10. 75 FR 73966 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2010-11-30

    ... Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship...; Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago Sanitary and Ship Canal... enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including Des Plaines...

  11. 78 FR 36091 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2013-06-17

    ... Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship...; Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago Sanitary and Ship Canal... the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago...

  12. 77 FR 35854 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2012-06-15

    ... Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship...; Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago Sanitary and Ship Canal... enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including Des Plaines...

  13. 75 FR 64673 - Safety Zone, Brandon Road Lock and, Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2010-10-20

    ... Zone, Brandon Road Lock and, Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and... Safety Zone, Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago Ship and...: The Coast Guard will enforce Safety Zone, Brandon Road Lock and Dam to Lake Michigan including Des...

  14. 77 FR 65478 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago...

    Science.gov (United States)

    2012-10-29

    ...-AA00 Safety Zone, Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago... the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago... segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including Des Plaines River...

  15. 76 FR 63199 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2011-10-12

    ... Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship...; Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago Sanitary and Ship Canal...; Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago Sanitary and Ship Canal...

  16. 76 FR 2829 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2011-01-18

    ... Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship...; Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago Sanitary and Ship Canal... enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including Des Plaines...

  17. 75 FR 52462 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2010-08-26

    ... Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship...; Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago Sanitary and Ship Canal... enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including Des Plaines...

  18. 77 FR 60044 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2012-10-02

    ...-AA00 Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago... the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago... segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including Des Plaines River...

  19. 75 FR 26094 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago...

    Science.gov (United States)

    2010-05-11

    ...-AA00 Safety Zone, Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago... establishing a temporary safety zone from Brandon Road Lock and Dam to Lake Michigan. This temporary safety...

  20. 76 FR 78161 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2011-12-16

    ... Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship...; Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago Sanitary and Ship Canal... INFORMATION: The Coast Guard will enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake...

  1. 78 FR 4071 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2013-01-18

    ...-AA00 Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago... the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago... Coast Guard will enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan...

  2. 78 FR 40635 - Safety Zone; Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2013-07-08

    ... Zone; Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship...; Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago Sanitary and Ship Canal... Coast Guard will enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan...

  3. 78 FR 36092 - Safety Zone; Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2013-06-17

    ... Zone; Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship...; Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago Sanitary and Ship Canal... Coast Guard will enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan...

  4. 75 FR 64147 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2010-10-19

    ... Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship...; Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago Ship and Sanitary Canal... . SUPPLEMENTARY INFORMATION: The Coast Guard will enforce Safety Zone, Brandon Road Lock and Dam to Lake Michigan...

  5. 76 FR 65609 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2011-10-24

    ... Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship Canal... Lock and Dam to Lake Michigan including Des Plaines River, Chicago Sanitary and Ship Canal, Chicago... INFORMATION: The Coast Guard will enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake...

  6. Cave Buttes Dam Master Plan, Phoenix, Arizona and Vicinity (Including New River).

    Science.gov (United States)

    1982-03-01

    New River Dam (including May 1982 New River to Skunk Creek) Part 4--Skunk Creek and New and July 1984 Agua Fria Rivers below the Arizona Canal...Groundwater is a potential source, as existing wells in the area provided potable water for homes. D. WASTE TREATMENT SYSTEM The type and extent of

  7. Mathematical Modeling in Systems for Operational Evaluation of the Stress-Strain State of the Arch-Gravity Dam at the Sayano-Shushenskaya Hydroelectric Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Bellendir, E. N.; Gordon, L. A., E-mail: lev-gordon@mail.ru; Khrapkov, A. A.; Skvortsova, A. E., E-mail: SkvortsovaAE@vniig.ru [B. E. Vedeneev All-Russia Research Institute of Hydraulic Engineering (VNIIG) (Russian Federation)

    2017-01-15

    Current studies of the stress-strain state of the dam at the Sayano-Shushenskaya Hydroelectric Power Plant at VNIIG based on mathematical modeling including full scale and experimental data are described. Applications and programs intended for automatic operational evaluation of the stress-strain state of the dam for optimizing control of the upper race level in the course of the annual filling-drawdown cycle and during seismic events are examined. Improvements in systems for monitoring the stress-strain state of concrete dams are proposed.

  8. Technical bulletin : structural considerations for dam safety

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    This technical bulletin discussed issues related to the safety assessment of concrete water-retaining structures and timber dams. Structures reviewed in the paper included gravity dams; buttress dams; arch dams; spillway structures; intake structures; power plants; roller compacted concrete dams; and timber dams. A variety of issues related to the loss of cohesive bond and discontinuities in bedrock foundations were reviewed with reference to issues related to compressive strength, tensile strength, and shear strength. Static failure modes and failure mechanisms related to dam failures were also described. Visual indicators for potential failures include abutment and foundation movement, seepage, and structure movements. Loading combinations were discussed, and performance indicators for gravity dams were provided. Methods of analysis for considering load characteristics, structure types and geological conditions were also discussed. Modelling techniques for finite element analysis were also included. 16 refs., 3 tabs., 5 figs.

  9. 76 FR 35106 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2011-06-16

    ...-AA00 Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago..., DHS. ACTION: Final rule. SUMMARY: The Coast Guard is establishing a permanent safety zone from Brandon... Safety Zones; Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago Sanitary...

  10. 77 FR 25595 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2012-05-01

    ... Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship...; Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago Sanitary and Ship Canal... Safety Zone; Brandon Road Lock and [[Page 25596

  11. 76 FR 23524 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2011-04-27

    ...-AA00 Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago... safety zone from Brandon Road Lock and Dam to Lake Michigan. This proposed safety zone will cover 77.... This TIR established a 77 mile long safety zone from Brandon Road Lock to Lake Michigan in Chicago, IL...

  12. Deformation mechanism of the dam heel of Dagangshan high arch dam based on microseismic monitoring during initial impoundment%基于微震监测的大岗山高拱坝坝踵蓄水初期变形机制研究

    Institute of Scientific and Technical Information of China (English)

    马克; 金峰; 唐春安; 吕鹏飞; 庄端阳

    2017-01-01

    混凝土高拱坝坝踵是蓄水初期阶段拱坝安全的重点关注部位.通过构建国内首套高拱坝坝踵微震监测系统,实现对蓄水初期阶段大岗山拱坝坝踵区微破裂的实时监测,探究坝踵蓄水初期变形机制及其与微震活动性的关系.采用人工敲击试验确定坝踵等效P波波速为4 300 rn/s,系统定位误差小于8m.对系统获取的事件波形进行噪声滤除,并在自动定位基础上进行人工二次校核,提高定位精度,验证了微震监测技术应用于大体积混凝土工程的可行性.分析认为:蓄水初期阶段,大岗山高拱坝坝踵区微震活动性与库水位密切相关,微震事件聚集区实现从坝踵向坝趾的转移,坝踵压缩变形减小,而坝趾区变形量增加.此外,通过拱坝坝踵区微震变形演化过程,揭示了导流洞下闸蓄水前940 m高程基础廊道拱顶裂缝产生的根本诱因.研究成果可为混凝土高拱坝微震监测和真实工作性态研究提供参考.%The safety of the heel of the concrete high arch dam is highly concemed during the initial impoundment.The microseismic monitoring system was installed for the first time in China at the high arch dam heel.The real-time monitoring of the micro-cracks was achieved in the heel zone of the Dagangshan arch dam during the initial impoundment.The deformation mechanism of the arch dam heel and its relationship with the microseismic activities were investigated.The P wave velocity was determined using the manual tapping test and was 4 300 m/s with the error of system positioning less than 8 m.The event waveforms were denoised.The automatic positioning results were manually verified for better accuracy.The results proved the feasibility of applying the microseismic monitoring technology in the large-scale concrete structures.During the initial impoundment period,the microseismic activities of the high arch dam heel were closely related to the water level of reservoir.The accumulation

  13. Dam! Dam! Dam!

    International Nuclear Information System (INIS)

    McCully, P.

    1997-01-01

    The author of ''Silenced Rivers'' a book questioning the desirability of dam building and hydroelectric power generation argues the main themes of his book in this paper. Despite being hailed by politicians as good solutions to power generation problems, and enthusiastically pursued in China, the U.S.A., the former Soviet Union, India and Japan, dams have far-reaching ecological and human consequences. The ecosystems lost to flooding, and the agricultural land use lost, the human cost in terms of homes and employment lost to reservoirs, disease from water-borne infections such as malaria, and the hazards of dams overflowing or breaking are all factors which are against the case for dam construction. The author argues the hydroelectric power may be renewable, but the social, agricultural and ecological costs are too high to justify it as a method of first choice. (UK)

  14. Displacement response of a concrete arch dam to seasonal temperature fluctuations and reservoir level rise during the first filling period: evidence from geodetic data

    Directory of Open Access Journals (Sweden)

    Cemal Ozer Yigit

    2016-07-01

    Full Text Available The present study evaluates the dynamic behaviour of the Ermenek Dam, the second highest dam in Turkey, based on conventional geodetic measurements and Finite Element Model (FEM analyses during its first filling period. In total, eight periods of measured deformation are considered from the end of construction until the reservoir reached its full capacity. The displacement response of the dam to the reservoir level and to seasonal temperature variations is examined in detail. Time series of apparent total displacements at the middle of the crest of the dam exhibits periodicity and linear trends. Correlation analysis revealed that periodic and linear displacement responses of the dam are related to variations of seasonal temperature and linearly increased reservoir level, respectively, indicating a relation between temperature, water load and dam deformation. It is also concluded that measured deformations based on geodetic data show good agreement with the predicted deformation obtained by the FEM analysis.

  15. Hypergravity disruption of homeorhetic adaptations to lactation in rat dams include changes in circadian clocks

    Directory of Open Access Journals (Sweden)

    Theresa Casey

    2012-04-01

    Altered gravity load induced by spaceflight (microgravity and centrifugation (hypergravity is associated with changes in circadian, metabolic, and reproductive systems. Exposure to 2-g hypergravity (HG during pregnancy and lactation decreased rate of mammary metabolic activity and increased pup mortality. We hypothesize HG disrupted maternal homeorhetic responses to pregnancy and lactation are due to changes in maternal metabolism, hormone concentrations, and maternal behavior related to gravity induced alterations in circadian clocks. Effect of HG exposure on mammary, liver and adipose tissue metabolism, plasma hormones and maternal behavior were analyzed in rat dams from mid-pregnancy (Gestational day [G]11 through early lactation (Postnatal day [P]3; comparisons were made across five time-points: G20, G21, P0 (labor and delivery, P1 and P3. Blood, mammary, liver, and adipose tissue were collected for analyzing plasma hormones, glucose oxidation to CO2 and incorporation into lipids, or gene expression. Maternal behavioral phenotyping was conducted using time-lapse videographic analyses. Dam and fetal-pup body mass were significantly reduced in HG in all age groups. HG did not affect labor and delivery; however, HG pups experienced a greater rate of mortality. PRL, corticosterone, and insulin levels and receptor genes were altered by HG. Mammary, liver and adipose tissue metabolism and expression of genes that regulate lipid metabolism were altered by HG exposure. Exposure to HG significantly changed expression of core clock genes in mammary and liver and circadian rhythms of maternal behavior. Gravity load alterations in dam's circadian system may have impacted homeorhetic adaptations needed for a successful lactation.

  16. The mathematics of dam safety

    Energy Technology Data Exchange (ETDEWEB)

    Widmann, R. [Osterreichische Gesellschaft fuer Geomechanik, Salzburg (Austria)

    1997-05-01

    The safety of a dam is determined by its design, construction and supervision during operation. High arch dam failures have dropped dramatically since the early part of this century. An essential part of the success story relates to improved measurement techniques that can detect earlier unexpected behaviour that may lead to failure. (UK)

  17. Intraoral gothic arch tracing.

    Science.gov (United States)

    Rubel, Barry; Hill, Edward E

    2011-01-01

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

  18. NRC inventory of dams

    International Nuclear Information System (INIS)

    Lear, G.E.; Thompson, O.O.

    1983-01-01

    The NRC Inventory of Dams has been prepared as required by the charter of the NRC Dam Safety Officer. The inventory lists 51 dams associated with nuclear power plant sites and 14 uranium mill tailings dams (licensed by NRC) in the US as of February 1, 1982. Of the 85 listed nuclear power plants (148 units), 26 plants obtain cooling water from impoundments formed by dams. The 51 dams associated with the plants are: located on a plant site (29 dams at 15 plant sites); located off site but provide plant cooling water (18 dams at 11 additional plant sites); and located upstream from a plant (4 dams) - they have been identified as dams whose failure, and ensuing plant flooding, could result in a radiological risk to the public health and safety. The dams that might be considered NRC's responsibility in terms of the federal dam safety program are identified. This group of dams (20 on nuclear power plant sites and 14 uranium mill tailings dams) was obtained by eliminating dams that do not pose a flooding hazard (e.g., submerged dams) and dams that are regulated by another federal agency. The report includes the principal design features of all dams and related useful information

  19. Tailings dams from the perspective of conventional dam engineering

    International Nuclear Information System (INIS)

    Szymanski, M.B.

    1999-01-01

    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

  20. 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...

  1. Factors influencing hysteresis characteristics of concrete dam deformation

    Directory of Open Access Journals (Sweden)

    Jia-he Zhang

    2017-04-01

    Full Text Available Thermal deformation of a concrete dam changes periodically, and its variation lags behind the air temperature variation. The lag, known as the hysteresis time, is generally attributed to the low velocity of heat conduction in concrete, but this explanation is not entirely sufficient. In this paper, analytical solutions of displacement hysteresis time for a cantilever beam and an arch ring are derived. The influence of different factors on the displacement hysteresis time was examined. A finite element model was used to verify the reliability of the theoretical analytical solutions. The following conclusions are reached: (1 the hysteresis time of the mean temperature is longer than that of the linearly distributed temperature difference; (2 the dam type has a large impact on the displacement hysteresis time, and the hysteresis time of the horizontal displacement of an arch dam is longer than that of a gravity dam; (3 the reservoir water temperature variation lags behind of the air temperature variation, which intensifies the differences in the horizontal displacement hysteresis time between the gravity dam and the arch dam; (4 with a decrease in elevation, the horizontal displacement hysteresis time of a gravity dam tends to increase, whereas the horizontal displacement hysteresis time of an arch dam is likely to increase initially, and then decrease; and (5 along the width of the dam, the horizontal displacement hysteresis time of a gravity dam decreases as a whole, while the horizontal displacement hysteresis time of an arch dam is shorter near the center and longer near dam surfaces.

  2. ArchE - An Architecture Design Assistant

    Science.gov (United States)

    2007-08-02

    Architecture Design Assistant Len Bass August 2, 2007 Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the...ArchE - An Architecture Design Assistant 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK...X, Module X 3 Author / Presenter, Date if Needed What is ArchE? ArchE is a software architecture design assistant, which: • Takes quality and

  3. A Markov chain analysis of the movements of juvenile salmonids, including sockeye salmon, in the forebay of McNary Dam, Washington and Oregon, 2006-09

    Science.gov (United States)

    Adams, Noah S.; Hatton, Tyson W.

    2012-01-01

    Passage and survival data were collected at McNary Dam between 2006 and 2009. These data have provided critical information for resource managers to implement structural and operational changes designed to improve the survival of juvenile salmonids as they migrate past the dam. Much of the valuable information collected at McNary Dam was in the form of three-dimensional (hereafter referred to as 3-D) tracks of fish movements in the forebay. These data depicted the behavior of multiple species (in three dimensions) during different diel periods, spill conditions, powerhouse operations, and testing of the surface bypass structures (temporary spillway weirs; TSWs). One of the challenges in reporting 3-D results is presenting the information in a manner that allows interested parties to summarize the behavior of many fish over many different conditions across multiple years. To accomplish this, we used a Markov chain analysis to characterize fish movement patterns in the forebay of McNary Dam. The Markov chain analysis allowed us to numerically summarize the behavior of fish in the forebay. This report is the second report published in 2012 that uses this analytical method. The first report included only fish released as part of the annual studies conducted at McNary Dam. This second report includes sockeye salmon that were released as part of studies conducted by the Chelan and Grant County Public Utility Districts at mid-Columbia River dams. The studies conducted in the mid-Columbia used the same transmitters as were used for McNary Dam studies, but transmitter pulse width was different between studies. Additionally, no passive integrated transponder tags were implanted in sockeye salmon. Differences in transmitter pulse width resulted in lower detection probabilities for sockeye salmon at McNary Dam. The absence of passive integrated transponder tags prevented us from determining if fish passed the powerhouse through the juvenile bypass system (JBS) or turbines. To

  4. Evaluation of a Behavioral Guidance Structure at Bonneville Dam Second Powerhouse including Passage Survival of Juvenile Salmon and Steelhead using Acoustic Telemetry, 2008

    Energy Technology Data Exchange (ETDEWEB)

    Faber, Derrek M.; Ploskey, Gene R.; Weiland, Mark A.; Deng, Zhiqun; Hughes, James S.; McComas, Roy L.; Kim, Jina; Townsend, R. L.; Fu, Tao; Skalski, J. R.; Fischer, Eric S.

    2010-02-12

    Summarizes research conducted at Bonneville Dam in 2008 to evaluate a prototype Behavioral Guidance Structure, that was deployed by the US Army Corps of Engineers in an effort to increase survival of outmigrating smolts at Bonneville Dam.

  5. The occurrence and removal of algae (including cyanobacteria) and their related organic compounds from source water in Vaalkop Dam with conventional and advanced drinking water treatment processes

    OpenAIRE

    Swanepoel, A; Du Preez, HH; Cloete, N

    2017-01-01

    Cyanobacterial bloom formation in freshwaters, such as rivers, lakes and dams, is known to occur throughout the world. The Vaalkop Dam, which serves as source to the Vaalkop drinking water treatment works (DWTW), is no exception. Blooms of cyanobacteria occur annually in Vaalkop Dam as well as in dams from which Vaalkop is replenished during low-rainfall periods. These blooms during the summer months are associated with the production of cyanotoxins and taste and odour compounds such as geosm...

  6. Dams designed to fail

    Energy Technology Data Exchange (ETDEWEB)

    Penman, A. [Geotechnical Engineering Consultants, Harpenden (United Kingdom)

    2004-09-01

    New developments in geotechnical engineering have led to methods for designing and constructing safe embankment dams. Failed dams can be categorized as those designed to fail, and those that have failed unexpectedly. This presentation outlined 3 dam failures: the 61 m high Malpasset Dam in France in 1959 which killed 421; the 71 m high Baldwin Hills Dam in the United States in 1963 which killed 5; and, the Vajont Dam in Italy in 1963 which killed 2,600 people. Following these incidents, the International Commission for Large Dams (ICOLD) reviewed regulations on reservoir safety. The 3 dams were found to have inadequate spillways and their failures were due to faults in their design. Fuse plug spillways, which address this problem, are designed to fail if an existing spillway proves inadequate. They allow additional discharge to prevent overtopping of the embankment dam. This solution can only be used if there is an adjacent valley to take the additional discharge. Examples of fuse gates were presented along with their effect on dam safety. A research program is currently underway in Norway in which high embankment dams are being studied for overtopping failure and failure due to internal erosion. Internal erosion has been the main reason why dams have failed unexpectedly. To prevent failures, designers suggested the use of a clay blanket placed under the upstream shoulder. However, for dams with soft clay cores, these underblankets could provide a route for a slip surface and that could lead to failure of the upstream shoulder. It was concluded that a safe arrangement for embankment dams includes the use of tipping gates or overturning gates which always fail at a required flood water level. Many have been installed in old and new dams around the world. 14 refs., 19 figs.

  7. Mechanics of slide dams

    International Nuclear Information System (INIS)

    Young, G.A.

    1970-01-01

    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)

  8. Mechanics of slide dams

    Energy Technology Data Exchange (ETDEWEB)

    Young, G A [Engineering, Agbabian-Jacobsen Associates, Los Angeles (United States)

    1970-05-15

    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)

  9. 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.

  10. 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.

  11. 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.

  12. 33 CFR 165.T09-0166 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago...

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Safety Zone, Brandon Road Lock... Areas Ninth Coast Guard District § 165.T09-0166 Safety Zone, Brandon Road Lock and Dam to Lake Michigan.... waters of the Des Plaines River located between mile marker 286.0 (Brandon Road Lock and Dam) and mile...

  13. Spruce Lake Dam reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Snyder, G. [SGE Acres Ltd., Fredericton, NB (Canada); Barnard, J. [SGE Acres Ltd., St. John' s, NF (Canada); Vriezen, C. [City of Saint John, NF (Canada); Stephenson, M. [Jacques Whitford Environment Ltd., Fredericton, NB (Canada)

    2004-09-01

    Spruce Lake Dam was constructed in 1898 as part of the water supply system for Saint John, New Brunswick. The original dam was a 6 meter high, 140 meter long concrete gravity dam with an intake structure at its mid point and an overflow spillway at the left abutment. A rehabilitation project was launched in 2001 to bring the deteriorated dam into conformance with the dam safety guidelines of the Canadian Dam Association. The project criteria included minimal disruption to normal operation of water supply facilities and no negative effect on water quality. The project involved installation of a new low level outlet, removal of a gate house and water intake pipes, replacement of an access road culvert in the spillway channel, and raising the earth dam section by 1.8 meters to allow for increased water storage. The new raised section has an impervious core. The project also involved site and geotechnical investigations as well as hydrotechnical and environmental studies. This presentation described the final design of the remedial work and the environmental permitting procedures. Raising the operating level of the system proved successful as demonstrated by the fewer number of pumping days required after dam rehabilitation. The dam safety assessment under the Canadian Environmental Assessment Act began in April 2001, and the rehabilitation was completed by the end of 2002. 1 tab., 8 figs.

  14. 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.)

  15. Aortic arch malformations

    International Nuclear Information System (INIS)

    Kellenberger, Christian J.

    2010-01-01

    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.)

  16. Cable strengthened arches

    NARCIS (Netherlands)

    Kamerling, M.W.

    2013-01-01

    The structural efficiency of arches, subjected to several variable loads, can be increased by strengthening these arches with cables. For these structures it can be necessary, especially in case the permanent load is small, to post-tension the cables to avoid any compression acting on the cables. A

  17. Concrete-Filled Steel Tube Arch Bridges in China

    Directory of Open Access Journals (Sweden)

    Jielian Zheng

    2018-02-01

    Full Text Available In the past 20 years, great progress has been achieved in China in the construction of concrete-filled steel tube (CFST arch bridges and concrete arch bridges with a CFST skeleton. The span of these bridges has been increasing rapidly, which is rare in the history of bridge development. The large-scale construction of expressways and high-speed railways demands the development of long-span arch bridges, and advances in design and construction techniques have made it possible to construct such bridges. In the present study, the current status, development, and major innovative technologies of CFST arch bridges and concrete arch bridges with a CFST skeleton in China are elaborated. This paper covers the key construction technologies of CFST arch bridges, such as the design, manufacture, and installation of steel tube arch trusses, the preparation and pouring of in-tube concrete, and the construction of the world’s longest CFST arch bridge—the First Hejiang Yangtze River Bridge. The main construction technologies of reinforced concrete arch bridges are also presented, which include cable-stayed fastening-hanging cantilever assembly, adjusting the load by means of stay cables, surrounding the concrete for arch rib pouring, and so forth. In addition, the construction of two CFST skeleton concrete arch bridges—the Guangxi Yongning Yong River Bridge and the Yunnan–Guangxi Railway Nanpan River Bridge—is discussed. CFST arch bridges in China have already gained a world-leading position; with the continuous innovation of key technologies, China will become the new leader in promoting the development of arch bridges. Keywords: Concrete-filled steel tube (CFST arch bridge, Steel-reinforced concrete arch bridge, Cable-stayed fastening-hanging cantilever assembly, Vacuum-assisted pouring in-tube concrete, Adjusting load by stay cables

  18. Comparison of Total Arch and Partial Arch Transposition During Hybrid Endovascular Repair for Aortic Arch Disease.

    Science.gov (United States)

    Kang, W C; Ko, Y-G; Oh, P C; Shin, E K; Park, C-H; Choi, D; Youn, Y N; Lee, D Y

    2016-08-01

    Total arch transposition (TAT) during hybrid endovascular repair for aortic arch disease is believed to allow a better landing zone, but also to be associated with higher peri-operative mortality than partial arch transposition (PAT). Information on this issue is limited. This study was a retrospective analysis. All 53 consecutive patients with aortic arch disease (41 males, mean age 65.0 years) who underwent hybrid endovascular repair with TAT (zone 0, n=20) or PAT (zone 1 or 2, n=33) from 2008 to 2014 were analyzed retrospectively. The peri-operative and late outcomes of these two groups were compared. Baseline characteristics, including EuroSCORE II results, were similar in the two groups. After procedures, peri-operative mortalities and stroke rates were similar in the two groups (5.0% vs. 9.1%, p=1.000, and 10.0% vs. 6.1%, p=.627). Interestingly, all four strokes occurred in patients with a type III aortic arch irrespective of transposition type. Primary success rates (80.0% vs. 69.7%, p=.527) and type I endoleak incidences (20.0% vs. 27.3%, p=.744) were not significantly different. During follow up (mean duration 36.9 months), overall survival (89.7% vs. 87.4% at 1 year and 89.7% vs. 79.3% at 3 years; p=.375) and re-intervention free survival rates (78.6% vs. 92.0% at 1 year; 72.0% vs. 62.2% at 3 years, p=.872) were similar in the two groups. Morbidity and mortality were high within the first year of hybrid endovascular therapy for aortic arch disease, implying that candidates for hybrid procedures need to be selected carefully. Hybrid endovascular repair with TAT was found to have peri-operative mortality, stroke, and long-term survival rates comparable with PAT, so hybrid endovascular repair may be considered, irrespective of type of arch reconstruction, when clinically indicated. Copyright © 2016 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

  19. Dam safety operating guidelines

    International Nuclear Information System (INIS)

    Elsayed, E.; Leung, T.; Kirkham, A.; Lum, D.

    1990-01-01

    As part of Ontario Hydro's dam structure assessment program, the hydraulic design review of several river systems has revealed that many existing dam sites, under current operating procedures, would not have sufficient discharge capacity to pass the Inflow Design Flood (IDF) without compromising the integrity of the associated structures. Typical mitigative measures usually considered in dealing with these dam sites include structural alterations, emergency action plans and/or special operating procedures designed for extreme floods. A pilot study was carried out for the Madawaska River system in eastern Ontario, which has seven Ontario Hydro dam sites in series, to develop and evaluate the effectiveness of the Dam Safety Operating Guidelines (DSOG). The DSOG consist of two components: the flood routing schedules and the minimum discharge schedules, the former of which would apply in the case of severe spring flood conditions when the maximum observed snowpack water content and the forecast rainfall depth exceed threshold values. The flood routing schedules would identify to the operator the optimal timing and/or extent of utilizing the discharge facilities at each dam site to minimize the potential for dam failures cased by overtopping anywhere in the system. It was found that the DSOG reduced the number of structures overtopped during probable maximum flood from thirteen to four, while the number of structures that could fail would be reduced from seven to two. 8 refs., 4 figs., 3 tabs

  20. Islamic Architecture and Arch

    Directory of Open Access Journals (Sweden)

    Mohammed Mahbubur Rahman

    2015-01-01

    Full Text Available The arch, an essential architectural element since the early civilizations, permitted the construction of lighter walls and vaults, often covering a large span. Visually it was an important decorative feature that was trans-mitted from architectural decoration to other forms of art worldwide. In early Islamic period, Muslims were receiving from many civilizations, which they improved and re-introduced to bring about the Renaissance. Arches appeared in Mesopotamia, Indus, Egyptian, Babylonian, Greek and Assyrian civilizations; but the Romans applied the technique to a wide range of structures. The Muslims mastered the use and design of the arch, employed for structural and functional purposes, progressively meeting decorative and symbolic pur-poses. Islamic architecture is characterized by arches employed in all types of buildings; most common uses being in arcades. This paper discusses the process of assimilation and charts how they contributed to other civilizations.

  1. RARE BRANCHIAL ARCH ANOMALIES

    Directory of Open Access Journals (Sweden)

    Jayanta Kumar

    2016-03-01

    Full Text Available AIM Amongst the branchial arch anomalies third arch anomaly occurs rarely and more so the fourth arch anomalies. We present our experience with cases of rare branchial arch anomalies. PATIENTS AND METHODS From June 2006 to January 2016, cases having their external opening in the lower third of sternocleidomastoid muscle with the tract going through thyroid gland and directing to pyriform sinus (PFS or cysts with internal opening in the PFS were studied. RESULTS No fourth arch anomaly was encountered. One cyst with internal opening which later on formed a fistula, three fistulae from beginning and two sinuses were encountered. The main stay of diagnosis was the fistula in the PFS and the tract lying posterior to the internal carotid artery. Simple excision technique with a small incision around the external opening was done. There was no recurrence. CONCLUSION Third arch fistula is not very rare as it was thought. Internal fistula is found in most of the cases. Though radiological investigations are helpful, fistulae can be diagnosed clinically and during operation. Extensive operation of the neck, mediastinum and pharynx is not required.

  2. 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.

  3. Double aortic arch

    Science.gov (United States)

    Surgery can be done to fix double aortic arch. The surgeon ties off the smaller branch and separates it from the larger branch. Then the surgeon closes the ends of the aorta with stitches. This relieves pressure on the esophagus and windpipe.

  4. Electrothermally Tunable Arch Resonator

    KAUST Repository

    Hajjaj, Amal Z.

    2017-03-18

    This paper demonstrates experimentally, theoretically, and numerically a wide-range tunability of electrothermally actuated microelectromechanical arch beams. The beams are made of silicon and are intentionally fabricated with some curvature as in-plane shallow arches. An electrothermal voltage is applied between the anchors of the beam generating a current that controls the axial stress caused by thermal expansion. When the electrothermal voltage increases, the compressive stress increases inside the arch beam. This leads to an increase in its curvature, thereby increasing its resonance frequencies. We show here that the first resonance frequency can increase monotonically up to twice its initial value. We show also that after some electrothermal voltage load, the third resonance frequency starts to become more sensitive to the axial thermal stress, while the first resonance frequency becomes less sensitive. These results can be used as guidelines to utilize arches as wide-range tunable resonators. Analytical results based on the nonlinear Euler Bernoulli beam theory are generated and compared with the experimental data and the results of a multi-physics finite-element model. A good agreement is found among all the results. [2016-0291

  5. Level-ARCH Short Rate Models with Regime Switching

    DEFF Research Database (Denmark)

    Christiansen, Charlotte

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

  6. 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

  7. Non uniform nature of recorded ground accelerations at dam foundation interface

    Energy Technology Data Exchange (ETDEWEB)

    Ghaemian, Mohsen; Gilani, Morteza Sohrabi [Sharif University of Technology, Tehran, (Iran, Islamic Republic of); Noorzad, Ali [Power and Water University of Technology, Tehran, (Iran, Islamic Republic of)

    2010-07-01

    The Karun III is a double curved concrete arch dam located in Iran which was used to investigate earthquake motions and dam responses. This paper presented the study of the Karun III dam foundation interface. Using an array of 15 accelerometers, two major events that occurred on 2007.11.20 and 2007.11.21 were recorded during dam operation with a PGA at crest of 0.312 g and 0.109.g respectively. A finite element model of Karun III dam was performed. The response of the Karun III dam during the 2007 earthquake was investigated using the NSAD-DRI program. It was found that the motion of the dam foundation interface is non-uniform. There is a time shift and amplification at the abutment compared to those at the base of the dam. The results showed that the spatially varying earthquake assumption is in good agreement with the recorded displacement of the dam.

  8. Validation study by finite element method: the case of the Daniel Johnson Dam

    International Nuclear Information System (INIS)

    Lariviere, R.; Phat, T. M.; Poirier, C.; Thibeault, N.

    1997-01-01

    A structural study of the Daniel-Johnson multi-arch dam undertaken by Hydro-Quebec to determine the safest way of grouting the cracks at the base of some arches was described. A numerical model in the linear elastic domain was constructed. The model will be modified to incorporate other features such as the cracks at the base of arches, the cracks at the concrete-rock foundation contact area, and the restraining effect of downstream rock foundation. This paper highlights the quality assurance procedure related to model validation as recommended by the International Committee on Large Dams. 2 refs., 11 figs

  9. 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.

  10. 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.

  11. Assessing Risks of Mine Tailing Dam Failures

    Science.gov (United States)

    Concha Larrauri, P.; Lall, U.

    2017-12-01

    The consequences of tailings dam failures can be catastrophic for communities and ecosystems in the vicinity of the dams. The failure of the Fundão tailings dam at the Samarco mine in 2015 killed 19 people with severe consequences for the environment. The financial and legal consequences of a tailings dam failure can also be significant for the mining companies. For the Fundão tailings dam, the company had to pay 6 billion dollars in fines and twenty-one executives were charged with qualified murder. There are tenths of thousands of active, inactive, and abandoned tailings dams in the world and there is a need to better understand the hazards posed by these structures to downstream populations and ecosystems. A challenge to assess the risks of tailings dams in a large scale is that many of them are not registered in publicly available databases and there is little information about their current physical state. Additionally, hazard classifications of tailings dams - common in many countries- tend to be subjective, include vague parameter definitions, and are not always updated over time. Here we present a simple methodology to assess and rank the exposure to tailings dams using ArcGIS that removes subjective interpretations. The method uses basic information such as current dam height, storage volume, topography, population, land use, and hydrological data. A hazard rating risk was developed to compare the potential extent of the damage across dams. This assessment provides a general overview of what in the vicinity of the tailings dams could be affected in case of a failure and a way to rank tailings dams that is directly linked to the exposure at any given time. One hundred tailings dams in Minas Gerais, Brazil were used for the test case. This ranking approach could inform the risk management strategy of the tailings dams within a company, and when disclosed, it could enable shareholders and the communities to make decisions on the risks they are taking.

  12. Deformation performance of Waba Dam

    Energy Technology Data Exchange (ETDEWEB)

    Salloum, T.; Bhardwaj, V.; Hassan, P. [Ontario Power Generation, Niagara-on-the-Lake, ON (Canada); Cragg, C. [Cragg Consulting Services, Toronto, ON (Canada)

    2009-07-01

    This paper described the performance of the Waba Dam which is being monitored as part of Ontario Power Generation's Dam Safety Program. It described the deformations that have been observed in this 3600 ft long earthfill dam which lies on marine clay in eastern Ontario. An extensive instrumentation program, including foundation settlement gauges, surface monuments, slope inclinometers, load cells and piezometers has been in effect since the construction of the dam in 1975. Significant settlement has occurred at Waba Dam since its construction. Wide berms were provided upstream and downstream beyond the slopes of the main fill to ensure stability of the dyke on the soft clay foundation and the crest elevations were designed to allow for the expected settlement in the foundation which would be overstressed by the dam loading. Based on current settlements, future settlements are predicted based on Asaoka's method. Inclinometer measurements have shown a foundation lateral spreading of 12 in. The lateral versus vertical deformations were found to be comparable to well behaving embankments reported in the literature. These analyses indicate that Waba Dam is performing well and should continue to perform well into the future. 8 refs., 1 tab., 14 figs.

  13. On the response of large dams to incoherent seismic excitation

    International Nuclear Information System (INIS)

    Ramadan, O.; Novak, M.

    1993-01-01

    An intensive parametric study was conducted to investigate the response of concrete gravity dams to horizontal, spatially variable seismic ground motions. Both segmented dams consisting of separate blocks, or monoliths, and continuous monolithic dams are considered. The study includes the effects of various parameters on system natural frequencies, vibration modes, modal displacement ratios, as well as dam displacements and internal stresses due to spatially variable ground motions. The dam analytical model, and dam response to incoherent ground motions are described. The results show that the dam vibrates almost as a rigid body under the fully correlated waves, but bends and twists significantly under the spatially correlated motions. Dam-foundation interaction magnifies the low frequency components of the dam response, more so for a full reservoir, but decreases the high frequency components. For long dams, the effects of spatially incoherent ground motions are qualitatively different and can be much greater than those due to surface travelling waves. 3 refs., 3 figs

  14. 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

  15. Arch index and running biomechanics in children aged 10-14 years.

    Science.gov (United States)

    Hollander, Karsten; Stebbins, Julie; Albertsen, Inke Marie; Hamacher, Daniel; Babin, Kornelia; Hacke, Claudia; Zech, Astrid

    2018-03-01

    While altered foot arch characteristics (high or low) are frequently assumed to influence lower limb biomechanics and are suspected to be a contributing factor for injuries, the association between arch characteristics and lower limb running biomechanics in children is unclear. Therefore, the aim of this study was to investigate the relationship between a dynamically measured arch index and running biomechanics in healthy children. One hundred and one children aged 10-14 years were included in this study and underwent a biomechanical investigation. Plantar distribution (Novel, Emed) was used to determine the dynamic arch index and 3D motion capture (Vicon) to measure running biomechanics. Linear mixed models were established to determine the association between dynamic arch index and foot strike patterns, running kinematics, kinetics and temporal-spatial outcomes. No association was found between dynamic arch index and rate of rearfoot strikes (p = 0.072). Of all secondary outcomes, only the foot progression angle was associated with the dynamic arch index (p = 0.032) with greater external rotation in lower arched children. Overall, we found only few associations between arch characteristics and running biomechanics in children. However, altered foot arch characteristics are of clinical interest. Future studies should focus on detailed foot biomechanics and include clinically diagnosed high and low arched children. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Dams and Levees: Safety Risks

    Science.gov (United States)

    Carter, N. T.

    2017-12-01

    The nation's flood risk is increasing. The condition of U.S. dams and levees contributes to that risk. Dams and levee owners are responsible for the safety, maintenance, and rehabilitation of their facilities. Dams-Of the more than 90,000 dams in the United States, about 4% are federally owned and operated; 96% are owned by state and local governments, public utilities, or private companies. States regulate dams that are not federally owned. The number of high-hazard dams (i.e., dams whose failure would likely result in the loss of human life) has increased in the past decade. Roughly 1,780 state-regulated, high-hazard facilities with structural ratings of poor or unsatisfactory need rehabilitation. Levees-There are approximately 100,000 miles of levees in the nation; most levees are owned and maintained by municipalities and agricultural districts. Few states have levee safety programs. The U.S. Army Corps of Engineers (Corps) inspects 15,000 miles of levees, including levees that it owns and local levees participating in a federal program to assist with certain post-flood repairs. Information is limited on how regularly other levees are inspected. The consequence of a breach or failure is another aspect of risk. State and local governments have significant authority over land use and development, which can shape the social and economic impacts of a breach or failure; they also lead on emergency planning and related outreach. To date, federal dam and levee safety efforts have consisted primarily of (1) support for state dam safety standards and programs, (2) investments at federally owned dams and levees, and (3) since 2007, creation of a national levee database and enhanced efforts and procedures for Corps levee inspections and assessments. In Public Law 113-121, enacted in 2014, Congress (1) directed the Corps to develop voluntary guidelines for levee safety and an associated hazard potential classification system for levees, and (2) authorized support for the

  17. Mitigating Dam Impacts Using Environmental Flow Releases

    Science.gov (United States)

    Richter, B. D.

    2017-12-01

    One of the most ecologically disruptive impacts of dams is their alteration of natural river flow variability. Opportunities exist 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. 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. This presentation will highlight 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 suggested strategies for dam re-operation are predicated on changes in the end-use of the water, such as reductions in urban or agricultural water use during droughts, a systemic perspective of entire water management systems will be required to attain the fullest possible

  18. Electrostatically Tunable Nanomechanical Shallow Arches

    KAUST Repository

    Kazmi, Syed N. R.

    2017-11-03

    We report an analytical and experimental study on the tunability of in-plane doubly-clamped nanomechanical arches under varied DC bias conditions at room temperature. For this purpose, silicon based shallow arches are fabricated using standard e-beam lithography and surface nanomachining of a highly conductive device layer on a silicon-on-insulator (SOI) wafer. The experimental results show good agreement with the analytical results with a maximum tunability of 108.14% for 180 nm thick arch with a transduction gap of 1 μm between the beam and the driving/sensing electrodes. The high tunability of shallow arches paves the ways for highly tunable band pass filtering applications in high frequency range.

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

    Directory of Open Access Journals (Sweden)

    Martin Wieland

    2016-09-01

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

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

    International Nuclear Information System (INIS)

    Palmer, M.D.

    1999-01-01

    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

  1. Monitoring system of arch bridge for safety network management

    Science.gov (United States)

    Joo, Bong Chul; Yoo, Young Jun; Lee, Chin Hyung; Park, Ki Tae; Hwang, Yoon Koog

    2010-03-01

    Korea has constructed the safety management network monitoring test systems for the civil infrastructure since 2006 which includes airport structure, irrigation structure, railroad structure, road structure, and underground structure. Bridges among the road structure include the various superstructure types which are Steel box girder bridge, suspension bridge, PSC-box-girder bridge, and arch bridge. This paper shows the process of constructing the real-time monitoring system for the arch bridge and the measured result by the system. The arch type among various superstructure types has not only the structural efficiency but the visual beauty, because the arch type superstructure makes full use of the feature of curve. The main measuring points of arch bridges composited by curved members make a difference to compare with the system of girder bridges composited by straight members. This paper also shows the method to construct the monitoring system that considers the characteristic of the arch bridge. The system now includes strain gauges and thermometers, and it will include various sensor types such as CCTV, accelerometers and so on additionally. For the long term and accuracy monitoring, the latest optical sensors and equipments are applied to the system.

  2. Costa Rica's Presentation to the 1st Workshop on Problems of Leakage in Dams

    International Nuclear Information System (INIS)

    Cordero Calderon, C.F.

    1994-03-01

    This paper includes information about the Instituto Costarricense de Electricidad (ICE); the project T racer Application to Leakage in Dams; the description of the Cachi's Dam and the description of the Arenal's Dam. (S. Grainger)

  3. The Impact of Dam-Reservoir-Foundation Interaction on Nonlinear Response of Concrete Gravity Dams

    International Nuclear Information System (INIS)

    Amini, Ali Reza; Motamedi, Mohammad Hossein; Ghaemian, Mohsen

    2008-01-01

    To study the impact of dam-reservoir-foundation interaction on nonlinear response of concrete gravity dams, a two-dimensional finite element model of a concrete gravity dam including the dam body, a part of its foundation and a part of the reservoir was made. In addition, the proper boundary conditions were used in both reservoir and foundation in order to absorb the energy of outgoing waves at the far end boundaries. Using the finite element method and smeared crack approach, some different seismic nonlinear analyses were done and finally, we came to a conclusion that the consideration of dam-reservoir-foundation interaction in nonlinear analysis of concrete dams is of great importance, because from the performance point of view, this interaction significantly improves the nonlinear response of concrete dams

  4. 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.

  5. NASA ARCH- A FILE ARCHIVAL SYSTEM FOR THE DEC VAX

    Science.gov (United States)

    Scott, P. J.

    1994-01-01

    The function of the NASA ARCH system is to provide a permanent storage area for files that are infrequently accessed. The NASA ARCH routines were designed to provide a simple mechanism by which users can easily store and retrieve files. The user treats NASA ARCH as the interface to a black box where files are stored. There are only five NASA ARCH user commands, even though NASA ARCH employs standard VMS directives and the VAX BACKUP utility. Special care is taken to provide the security needed to insure file integrity over a period of years. The archived files may exist in any of three storage areas: a temporary buffer, the main buffer, and a magnetic tape library. When the main buffer fills up, it is transferred to permanent magnetic tape storage and deleted from disk. Files may be restored from any of the three storage areas. A single file, multiple files, or entire directories can be stored and retrieved. archived entities hold the same name, extension, version number, and VMS file protection scheme as they had in the user's account prior to archival. NASA ARCH is capable of handling up to 7 directory levels. Wildcards are supported. User commands include TEMPCOPY, DISKCOPY, DELETE, RESTORE, and DIRECTORY. The DIRECTORY command searches a directory of savesets covering all three archival areas, listing matches according to area, date, filename, or other criteria supplied by the user. The system manager commands include 1) ARCHIVE- to transfer the main buffer to duplicate magnetic tapes, 2) REPORTto determine when the main buffer is full enough to archive, 3) INCREMENT- to back up the partially filled main buffer, and 4) FULLBACKUP- to back up the entire main buffer. On-line help files are provided for all NASA ARCH commands. NASA ARCH is written in DEC VAX DCL for interactive execution and has been implemented on a DEC VAX computer operating under VMS 4.X. This program was developed in 1985.

  6. Construction of anhydrite dams

    Energy Technology Data Exchange (ETDEWEB)

    Bortoluzzi, L; Francois, G

    1977-05-01

    To construct a ventilation dam, the road is closed with a fibreglass sheet onto which 3 or 4 cm of anhydrite paste is sprayed. The equipment necessary is described, and the cost is compared with that of an aggregate dam.

  7. 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

  8. Developmental feature of the lumbosacral vertebral arch in childhood

    International Nuclear Information System (INIS)

    Yoshifuji, Kazuhisa; Morota, Nobuhito; Ihara, Satoshi

    2007-01-01

    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)

  9. 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.

  10. Dam removal: Listening in

    Science.gov (United States)

    Foley, M. M.; Bellmore, J. R.; O'Connor, J. E.; Duda, J. J.; East, A. E.; Grant, G. E.; Anderson, C. W.; Bountry, J. A.; Collins, M. J.; Connolly, P. J.; Craig, L. S.; Evans, J. E.; Greene, S. L.; Magilligan, F. J.; Magirl, C. S.; Major, J. J.; Pess, G. R.; Randle, T. J.; Shafroth, P. B.; Torgersen, C. E.; Tullos, D.; Wilcox, A. C.

    2017-07-01

    Dam removal is widely used as an approach for river restoration in the United States. The increase in dam removals—particularly large dams—and associated dam-removal studies over the last few decades motivated a working group at the USGS John Wesley Powell Center for Analysis and Synthesis to review and synthesize available studies of dam removals and their findings. Based on dam removals thus far, some general conclusions have emerged: (1) physical responses are typically fast, with the rate of sediment erosion largely dependent on sediment characteristics and dam-removal strategy; (2) ecological responses to dam removal differ among the affected upstream, downstream, and reservoir reaches; (3) dam removal tends to quickly reestablish connectivity, restoring the movement of material and organisms between upstream and downstream river reaches; (4) geographic context, river history, and land use significantly influence river restoration trajectories and recovery potential because they control broader physical and ecological processes and conditions; and (5) quantitative modeling capability is improving, particularly for physical and broad-scale ecological effects, and gives managers information needed to understand and predict long-term effects of dam removal on riverine ecosystems. Although these studies collectively enhance our understanding of how riverine ecosystems respond to dam removal, knowledge gaps remain because most studies have been short (< 5 years) and do not adequately represent the diversity of dam types, watershed conditions, and dam-removal methods in the U.S.

  11. Brazil's Amazonian dams: Ecological and socioeconomic impacts

    Science.gov (United States)

    Fearnside, P. M.

    2016-12-01

    Brazil's 2015-2024 Energy Expansion Plan calls for 11 hydroelectric dams with installed capacity ≥ 30 MW in the country's Amazon region. Dozens of other large dams are planned beyond this time horizon, and dams with environmental and socioeconomic impacts. Loss of forest to flooding is one, the Balbina and Tucuruí Dams being examples (each 3000 km2). If the Babaquara/Altamira Dam is built it will flood as much forest as both of these combined. Some planned dams imply loss of forest in protected areas, for example on the Tapajós River. Aquatic and riparian ecosystems are lost, including unique biodiversity. Endemic fish species in rapids on the Xingu and Tapajós Rivers are examples. Fish migrations are blocked, such as the commercially important "giant catfish" of the Madeira River. Dams emit greenhouse gases, including CO2 from the trees killed and CH4 from decay under anoxic conditions at the bottom of reservoirs. Emissions can exceed those from fossil-fuel generation, particularly over the 20-year period during which global emissions must be greatly reduced to meet 1.5-2°C limit agreed in Paris. Carbon credit for dams under the Climate Convention causes further net emission because the dams are not truly "additional." Anoxic environments in stratified reservoirs cause methylation of mercury present in Amazonian soils, which concentrates in fish, posing a health risk to human consumers. Population displacement is a major impact; for example, the Marabá Dam would displace 40,000 people, mostly traditional riverside dwellers (ribeirinhos). Various dams impact indigenous peoples, such as the Xingu River dams (beginning with Belo Monte) and the São Luiz do Tapajós and Chacorão Dams on the Tapajós River. Brazil has many energy options other than dams. Much energy use has little benefit for the country, such as exporting aluminum. Electric showerheads use 5% of the country's power. Losses in transmission lines (20%) are far above global averages and can be

  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. Rearfoot eversion has indirect effects on plantar fascia tension by changing the amount of arch collapse.

    Science.gov (United States)

    Lee, Sae Yong; Hertel, Jay; Lee, Sung Cheol

    2010-01-01

    Rearfoot eversion motion and arch height are believed to contribute to increased tension on the plantar fascia and arch collapse during gait but the specifics of these relationships are not clear. To examine the relationships among static arch height, rearfoot eversion, dynamic arch height, and plantar fascia tension. 28 healthy males participated. After static arch height was measured, the subjects were asked to run at 4.5m/s while frontal plane rearfoot motion, dynamic arch height, and ground reaction forces were collected. The relationships among variables were examined with bivariate correlations and path analysis. The results indicated a high correlation between dynamic arch height and static arch height (r=0.642), plantar fascia tension (r=-0.797), and maximum rearfoot eversion motion during gait (r=-0.518). The path analysis model without the direct rearfoot eversion effect explained 81.2% of the variance in plantar fascia tension, while the model with the direct rearfoot eversion effect explained 82.1% of the variance in plantar fascia tension. Including the indirect effect of maximum rearfoot eversion motion on plantar fascia tension through control of dynamic arch height is the model that best explains the interrelationships of these foot characteristics. The amount of maximum rearfoot eversion motion itself is not a good predictor of plantar fascia tension, however, together with the arch height, maximum rearfoot eversion motion is a good predictor because it has a pronounced indirect effect on plantar fascia tension. Copyright 2010. Published by Elsevier Ltd.

  14. National dam inventory provides data for analysis

    International Nuclear Information System (INIS)

    Spragens, L.

    1992-01-01

    The Association of State Dam Safety Officials completed a dam inventory this fall. Information on approximately 90,000 state-regulated dams in the US collected during the four-year inventory is being used to build a database managed by the Federal Emergency Management Agency. In addition to ASDSO's work, the federal government conducted an inventory of federal dams. This data will be added to the state information to form one national database. The database will feature 35 data fields for each entry, including the name of the dam, its size, the name of the nearest downstream community, maximum discharge and storage volume, the date of the last inspection, and details about the emergency action plan. The program is an update of the nation's first dam inventory, required by the Dam Safety Act of 1972. The US Army Corps of Engineers completed the original inventory in 1981. The Water Resources Development Act of 1986 authorized appropriations of $2.5 million for the Corps to update the inventory. FEMA and the Corps entered into an agreement for FEMA to undertake the task for the Corps and to coordinate work on both the federal and state inventories. ASDSO compiles existing information on state-regulated dams into a common format for the database, added missing information, and established a process for continually updating data. ASDSO plans to analyze the information collected for the database. It will look at statistics for the number of dams regulated, communities that could be affected, and the number of high-hazard dams. FEMA is preparing reports for Congress on the project. The reports, which are expected to be ready by May 1993, will include information on the methodology used and facts about regulated dams under state jurisdiction

  15. Comparison of Arch Width Changes Following Orthodontic ...

    African Journals Online (AJOL)

    2015-11-21

    Nov 21, 2015 ... Materials and Methods: The study was conducted with pre- and post-treatment digital models from ... or posterior arch width following orthodontic treatment ..... premolar extraction cases show significant arch width increases in ...

  16. Highly tunable NEMS shallow arches

    KAUST Repository

    Kazmi, Syed N. R.

    2017-11-30

    We report highly tunable nanoelectromechanical systems NEMS shallow arches under dc excitation voltages. Silicon based in-plane doubly clamped bridges, slightly curved as shallow arches, are fabricated using standard electron beam lithography and surface nanomachining of a highly conductive device layer on a silicon-on-insulator wafer. By designing the structures to have gap to thickness ratio of more than four, the mid-plane stretching of the nano arches is maximized such that an increase in the dc bias voltage will result into continuous increase in the resonance frequency of the resonators to wide ranges. This is confirmed analytically based on a nonlinear beam model. The experimental results are found to be in good agreement with that of the results from developed analytical model. A maximum tunability of 108.14% for a 180 nm thick arch with an initially designed gap of 1 μm between the beam and the driving/sensing electrodes is achieved. Furthermore, a tunable narrow bandpass filter is demonstrated, which opens up opportunities for designing such structures as filtering elements in high frequency ranges.

  17. Highly tunable NEMS shallow arches

    KAUST Repository

    Kazmi, Syed N. R.; Hajjaj, Amal Z.; Da Costa, Pedro M. F. J.; Younis, Mohammad I.

    2017-01-01

    and surface nanomachining of a highly conductive device layer on a silicon-on-insulator wafer. By designing the structures to have gap to thickness ratio of more than four, the mid-plane stretching of the nano arches is maximized such that an increase

  18. Electrostatically Tunable Nanomechanical Shallow Arches

    KAUST Repository

    Kazmi, Syed N. R.; Hajjaj, Amal Z.; Da Costa, Pedro M. F. J.; Younis, Mohammad I.

    2017-01-01

    -beam lithography and surface nanomachining of a highly conductive device layer on a silicon-on-insulator (SOI) wafer. The experimental results show good agreement with the analytical results with a maximum tunability of 108.14% for 180 nm thick arch with a

  19. Arch reconstruction with autologous pulmonary artery patch in interrupted aortic arch.

    Science.gov (United States)

    Lee, Won-Young; Park, Jeong-Jun

    2014-04-01

    Various surgical techniques have been developed for the repair of an interrupted aortic arch. However, tension and Gothic arch formation at the anastomotic site have remained major problems for these techniques: Excessive tension causes arch stenosis and left main bronchus compression, and Gothic arch configuration is related to cardiovascular complications. To resolve these problems, we adopted a modified surgical technique of distal aortic arch augmentation using an autologous main pulmonary artery patch. The descending aorta was then anastomosed to the augmented aortic arch in an end-to-side manner. Here, we report two cases of interrupted aortic arch that were repaired using this technique.

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

    Directory of Open Access Journals (Sweden)

    Ignacio Escuder-Bueno

    2016-09-01

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

  1. A bovine aortic arch in humans

    Directory of Open Access Journals (Sweden)

    María Elena Arnáiz-García

    2014-05-01

    Full Text Available We describe a curious congenital variation of human aortic arch (AA branching pattern termed the “bovine aortic arch”. Rather than arising directly from the AA as a separate branch as occurs in the most common AA branching pattern, the left common carotid artery moves to the right and merges from the brachiocephalic trunk. It is the normal AA branching pattern presented in a number of animals (canines, felines or Macaque monkeys but it has nothing to do with anatomy of AA in ruminant animals, including cattle and buffalo. That is why it is one of the most widely misnomers used in medical literature whose origin is nowadays unknown.

  2. Measuring and managing safety at Wahleach Dam

    International Nuclear Information System (INIS)

    Salmon, G. M.; Cattanach, J. D.; Hartford, D. N. D.

    1996-01-01

    Safety improvements recently implemented at the Wahleach Dam were described as one of the first instances in international dam safety practice where risk concepts have been used in conjunction with acceptable risk criteria to evaluate safety of a dam relative to required level of safety. Erosion was identified as the greatest threat to the safety of the dam. In addressing the deficiencies B.C. Hydro formulated a process which advocates a balanced level of safety,i.e. the probability of failure multiplied by the consequences of failure, integrated over a range of initiators. If the risk posed by the dam is lower than a 'tolerable' risk, the dam is considered to be safe enough. In the case of the Wahleach Dam, the inflow design flood (IDF) was selected to be about one half of the probable maximum flow (PMF), hence it was more likely than not that the spillway could pass floods up to and including the PMF. By accepting the determined level of risk, expenditures of several million dollars for design and construction of dam safety improvements were made redundant. Another byproduct of this new concept of risk assessment was the establishment of improved life safety protection by means of an early warning system for severe floods through the downstream community and emergency authorities. 3 refs., 5 tabs

  3. Restoring Environmental Flows by Modifying Dam Operations

    Directory of Open Access Journals (Sweden)

    Brian D. Richter

    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

  4. How big of an effect do small dams have? Using geomorphological footprints to quantify spatial impact of low-head dams and identify patterns of across-dam variation

    Science.gov (United States)

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

    2015-01-01

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

  5. Evaluation of arch form between Vietnamese and North American Caucasians using 3-dimensional virtual models.

    Science.gov (United States)

    Trang, Vu Thi Thu; Park, Jae Hyun; Bayome, Mohamed; Shastry, Shruti; Mellion, Alex; Kook, Yoon-Ah

    2015-01-01

    The purpose of this study was to investigate the three-dimensional (3D) morphologic differences in the mandibular arch of Vietnamese and North American White subjects. The sample included 113 Vietnamese subjects (41 Class I, 37 Class II and 35 Class III) and 96 White subjects (29 Class I, 30 Class II and 37 Class III). The samples were regrouped according to arch form types (tapered, ovoid, and square) to compare the frequency distribution of the three arch forms between ethnic groups in each angle classification. The facial axis point of each tooth was digitized on 3D virtual models. Four linear and two ratio variables were measured. In comparing arch dimensions, the intercanine and intermolar widths were wider in Vietnamese than in Whites (p Vietnamese group, the square arch form was the most frequent followed by tapered and ovoid arch forms. The arch forms of Whites were narrower than Vietnamese. In North American Whites, the distribution of the arch form types showed similar frequency. In Vietnamese, the square arch form was more frequent.

  6. 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.

  7. Dams and transnational advocacy: Political opportunities in transnational collective action

    Science.gov (United States)

    Fu, Teng

    Possible arguments to explain the gradual decline in big dam development and its site transferring from developed to developing countries include technical, economic, and political factors. This study focuses on the political argument---the rise of transnational anti-dam advocacy and its impact on state policy-making. Under what conditions does transnational anti-dam advocacy matter? Under what conditions does transnational advocacy change state dam policies (delay, scale down, or cancel)? It examines the role of transnational anti-dam actors in big dam building in a comparative context in Asia. Applying the social movement theory of political opportunity structure (POS) and using the qualitative case-study method, the study provides both within-case and cross-case analyses. Within-case analysis is utilized to explain the changing dynamics of big dam building in China (Three Gorges Dam and proposed Nu/Salween River dam projects), and to a lesser extent, Sardar Sarovar Project in India and Nam Theun 2 Dam in Laos. Different domestic and international POS (DPOS and IPOS) impact the strategies and outcomes of anti-dam advocacies in these countries. The degree of openness of the POS directly affects the capacity of transnational efforts in influencing state dam policies. The degree of openness or closure is measured by specific laws, institutions, discourse, or elite allies (or the absence of these) for the participation of non-state actors on big dam issues at a particular moment. This degree of openness is relative, varying over time, across countries and regions. This study finds that the impact of transnational anti-dam activism is most effective when both DPOS and IPOS are relatively open. Transnational anti-dam advocacy is least effective in influencing state dam policies when both DPOS and IPOS are relatively closed. Under a relatively open DPOS and closed IPOS, transnational anti-dam advocacy is more likely to successfully change state dam policies and even

  8. Tenaga Nasional Berhad dam safety and surveillance program

    International Nuclear Information System (INIS)

    Jansen Luis; Zulkhairi Abd Talib

    2006-01-01

    This paper discusses the current practice of dam surveillance, which includes dam monitoring which is a process of visual inspections, measuring, processing, compiling and analyzing dam instrumentation data to determine the performance of a dam. The prime objective of the dam surveillance system is to ensure that any occurrence and development of safety deficiencies and problems are quickly detected, identified, analyzed and the required remedial actions are determined and consequently carried out in due time. In brief, the section is responsible to ensure that the dam monitoring and surveillance works are implemented as per scheduled and in accordance with the requirement and guidelines prepared by the dam designers and in accordance with international commission on large dams, ICOLD. The paper also illustrates and recommends an alternative approach for dam surveillance program using risk management approach, which is currently being actively adopted by some countries like USA, Canada, Australia and etc, towards improving the dam safety management and the decision making process. The approach provides a wider area of opportunity, improvements and benefits particular in the evaluation and modifications to the dam performance and safety. The process provides an effective and efficient tool for the decision makers and engineers through a comprehensive evaluation and a good understanding of the hazards, risks and consequences in relation to dam safety investigations. (Author)

  9. Sinkhole remediation at Swinging Bridge Dam

    Energy Technology Data Exchange (ETDEWEB)

    Jones, A. [Devine Tarbell and Associates, Portland, ME (United States)

    2009-07-01

    This case history summary described a piping-related sinkhole that occurred after a flood at the Swinging Bridge Dam. The earth-filled embankment dam was constructed using a hydraulic fill technique. A foundation drilling and grouting program was constructed in areas of the dam founded on jointed sandstone and shale. The storage volumes of the reservoir is 32,000 acre-feet. A sinkhole 25 to 300 feet in diameter was observed on May 5, 2005 along the edge of the dam crest. The sinkhole extended to within 10 feet of the reservoir and was separated by a shallow berm of soil and driftwood. Cracking of the crest extended across an area of 180 feet. Operations staff notified the appropriate agencies, implemented a monitoring program, and mobilized construction equipment and sands for use as emergency sinkhole filler. An increase in tailrace turbidity was observed. Historical records for the dam showed significant cracking during the initial filling of the reservoir. Failure modes included increased pore pressures and seepages resulting in the piping of soil along the outside of the dam conduit. Emergency repairs included chemical grouting and weld repairs in the penstocks. A Federal Emergency Management Agency (FEMA) is currently addressing safety issues associated with conduits through dams. 4 refs., 11 figs.

  10. Recurrent neck infection with branchial arch fistula in children.

    Science.gov (United States)

    Madana, J; Yolmo, Deeke; Kalaiarasi, R; Gopalakrishnan, S; Saxena, S K; Krishnapriya, S

    2011-09-01

    Acute suppurative neck infections associated with third or fourth branchial arch fistulas are frequently recurrent. Third and fourth branchial arch anomalies are much less common than those of second arch and usually present with left thyroid lobe inflammation. The authors present their experience with 15 cases of pyriform sinus fistulae (PSF) of third branchial arch origin and 3 cases of fourth arch origin, all of which presented as recurrent neck infection mainly on the left side. A retrospective review of 18 cases of third and fourth arch fistulae treated at JIPMER from 2005 to 2010. This study includes 18 patients with PSF diagnosed by the existence of fistulous tract radiologically and intraoperatively with pathological correlation. Neck exploration with excision of tract and left hemithyroidectomy was performed in all cases. The patients consisted of 7 males and 11 females, and the ages ranged from 3 to 15 years. All of them presented with recurrent episodes of neck infection. Investigations performed include computed tomography (CT) fistulography, barium swallow and ultrasound which were useful in delineating pyriform sinus fistulous tract preoperatively. All cases were on the left side and the fistula was identified by barium swallow in 14 cases (80%), while intraoperative and pathologic confirmation of the tract was possible in all cases (100%). Neck exploration with an emphasis on complete exposure of the recurrent laryngeal nerve and exposure of the pyriform sinus opening to facilitate complete fistulous tract excision with left hemithyroidectomy was successful in all patients. A follow up period of 1-3 years showed no recurrence. Recurrent neck infection in a child should alert the physician to the possibility of an underlying pyriform sinus fistula of branchial origin and CT fistulography should be performed after the resolution of the neck infection to delineate the tract anatomically. Crown Copyright © 2011. Published by Elsevier Ireland Ltd. All

  11. Geophysics Methods in Electrometric Assessment of Dams

    Energy Technology Data Exchange (ETDEWEB)

    Davydov, V. A., E-mail: davydov-va@yandex.ru; Baidikov, S. V., E-mail: badikek@mail.ru; Gorshkov, V. Yu., E-mail: vitalaa@yandex.ru; Malikov, A. V., E-mail: alex.mal.1986@mail.ru [Russian Academy of Sciences, Geophysical Institute, Ural Branch (Russian Federation)

    2016-07-15

    The safety assessment of hydraulic structures is proposed to be conducted via geoelectric measurements, which are capable of assessing the health of earth dams in their natural bedding without intervention in their structure. Geoelectric measurements are shown as being capable of pinpointing hazardous parts of a dam, including areas of elevated seepage. Applications of such methods are shown for a number of mini-dams in the Sverdlovsk region. Aparameter (effective longitudinal conductivity) that may be used to monitor the safety of hydraulic structures is proposed. Quantitative estimates of this parameter are given in terms of the degree of safely.

  12. Large dams and risk management

    International Nuclear Information System (INIS)

    Cazelais, N.

    2003-01-01

    In July 1996, Quebec's Saguenay region was subjected to intensive rainfall which caused severe floods and uncontrolled release of several reservoirs, resulting in extensive damage to dam structures and reservoirs. The probability of occurrence for that disaster was 1:10,000. Following the disaster, the Quebec government established a dam management body entitled the Commission scientifique et technique sur la gestion des barrages, which pointed out several safety shortcomings of existing dams. Many were either very old or had undergone significant function change without being subsequently re-evaluated. A report by the Commission stated that damage following the floods could have been limited if the design and operating standards of the dams had been more stringent. A Dam Safety Act was adopted by the Quebec National Assembly on May 30, 2000 following recommendations to retain safer structures. The Act demands regular reporting of operating procedures. Seismic activity was noted as being a topic that requires in-depth examination since Quebec's St. Lawrence Valley, particularly the Charlevoix region, is one of Canada's largest seismic zones. The other is on the west coast in British Columbia. Earthquakes in Quebec are less intense than the ones in British Columbia, but they have higher frequency content which exerts a quasi-resonance wave effect which impacts roads, bridges, buildings and hydroelectric generating facilities. Hydro-Quebec is a public utility which owns 563 retaining structures, of which 228 are ranked as large dams that measure more than 15 metres high, 400 metres long and with a reservoir capacity of more than 1 million cubic metres of water. Hydro-Quebec addresses hydrological, seismic, technological and human risks through a dam safety procedure that includes structured plans for choosing best alternatives through staged exercises. Hazard levels are minimized through the adoption of emergency, prevention and alleviation measures. The utility

  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. 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.

  15. Contemporary results of surgical repair of recurrent aortic arch obstruction.

    Science.gov (United States)

    Mery, Carlos M; Khan, Muhammad S; Guzmán-Pruneda, Francisco A; Verm, Raymond; Umakanthan, Ramanan; Watrin, Carmen H; Adachi, Iki; Heinle, Jeffrey S; McKenzie, E Dean; Fraser, Charles D

    2014-07-01

    There is a paucity of data on the current outcomes of surgical intervention for recurrent aortic arch obstruction (RAAO) after initial aortic arch repair in children. The goal of this study is to report the long-term results in these patients. All patients undergoing surgical intervention for RAAO at Texas Children's Hospital from 1995 to 2012 were included. The cohort was divided into four groups based on initial procedure: (1) simple coarctation repair, (2) Norwood procedure, (3) complex congenital heart disease, and (4) interrupted aortic arch. A total of 48 patients age 9 months (range, 22 days to 36 years) underwent 49 procedures for RAAO. All patients had an anatomic repair consisting of either patch aortoplasty (n=27, 55%), aortic arch advancement (n=8, 16%), sliding arch aortoplasty (n=6, 12%), placement of an interposition graft (n=2, 17%), reconstruction with donor allograft (n=4, 8%), extended end-to-end anastomosis (n=1, 2%), or redo Norwood-type reconstruction (n=1, 2%). Most procedures (n=46, 94%) were performed through a median sternotomy using cardiopulmonary bypass. At a median follow-up of 6.1 years (range, 9 days to 17 years), only 2 patients required surgical or catheter-based intervention for RAAO. Hypertension was present in 10% of patients at last follow-up. There were no neurologic or renal complications. There was 1 perioperative death after an aortic arch advancement in group 1. Four other patients have died during follow-up, none of the deaths related to RAAO. Anatomic repair of RAAO is a safe procedure associated with low morbidity and mortality, and low long-term reintervention rates. Copyright © 2014 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  16. 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.

  17. [Outcomes of endovascular repairing aortic arch disease hybrid with supra-arch debranching procedures].

    Science.gov (United States)

    Wang, Mian; Chang, Guangqi; Yin, Henghui; Yao, Chen; Wang, Jinsong; Wang, Shenming

    2015-11-01

    To summarize the experience of endovascular repairing aortic arch disease hybrid with supra-arch debranching procedures. It was a retrospective study. From January 2002 to December 2014, 42 high risk patients with aortic arch disease were treated by supra-arch debranching hybrid with subsequent endovascular repair in the First Affiliated Hospital of Sun Yat-sen University. There were 39 male and 3 female patients with a mean age of (53±13) years (ranging from 34 to 80 years). Of the 42 patients, 7 were thoracic aortic aneurysm, 20 were Stanford type B aortic dissection and 15 were Stanford type A aortic dissection. After the supra-aortic debranching technique, simultaneous (n=16) or staged (n=26, mean interval (7±3) days) endovascular repair were performed. Fisher exact test was used to compare the in-hospital mortality of ascending aorta based debranching and non-ascending aorta based debranching. Technical success rate was 81.0% (34/42). The overall 30-day complication rate was 31.0% (13/42), including 3 cerebral stroke (7.1%), 8 endoleak (19.0%, including 6 type I endoleak and 2 type II endoleak), 1 circulatory failure, 1 aorto-tracheal fistula. The 30-day mortality was 9.5% (4/42), 2 died of cerebral stroke, 1 died of circulatory failure, 1 died of aorto-tracheal fistula. The in-hospital mortality of ascending aorta based debranching group was obviously higher than that of the non-ascending aorta based debranching group (4/16 vs. 0, P=0.02). The median time of follow-up was 64.8 (2 to 156.9) months. CT scanning was performed at 1, 3 months after surgery and annually thereafter. The overall survival rate was 76.6%. During the follow-up period, there was 4 deaths, and 2 of them were aortic artery related (5.3%). There were 4 de novo complications during the follow-up period, 1 stroke attributed to bypass occlusion was cured by medical treatment, 2 pseudoaneurysm was successfully treated with open surgery, 1 stent-graft induced new distal entry tear was

  18. Human evaluation in association to the mathematical analysis of arch forms: Two-dimensional study.

    Science.gov (United States)

    Zabidin, Nurwahidah; Mohamed, Alizae Marny; Zaharim, Azami; Marizan Nor, Murshida; Rosli, Tanti Irawati

    2018-03-01

    To evaluate the relationship between human evaluation of the dental-arch form, to complete a mathematical analysis via two different methods in quantifying the arch form, and to establish agreement with the fourth-order polynomial equation. This study included 64 sets of digitised maxilla and mandible dental casts obtained from a sample of dental arch with normal occlusion. For human evaluation, a convenient sample of orthodontic practitioners ranked the photo images of dental cast from the most tapered to the less tapered (square). In the mathematical analysis, dental arches were interpolated using the fourth-order polynomial equation with millimetric acetate paper and AutoCAD software. Finally, the relations between human evaluation and mathematical objective analyses were evaluated. Human evaluations were found to be generally in agreement, but only at the extremes of tapered and square arch forms; this indicated general human error and observer bias. The two methods used to plot the arch form were comparable. The use of fourth-order polynomial equation may be facilitative in obtaining a smooth curve, which can produce a template for individual arch that represents all potential tooth positions for the dental arch. Copyright © 2018 CEO. Published by Elsevier Masson SAS. All rights reserved.

  19. Tracheal Compression Caused by a Mediastinal Hematoma After Interrupted Aortic Arch Surgery.

    Science.gov (United States)

    Hua, Qingwang; Lin, Zhiyong; Hu, Xingti; Zhao, Qifeng

    2017-08-03

    Congenital abnormalities of the aortic arch include interrupted aortic arch (IAA), coarctation of the aorta (CoA), and double aortic arch (DAA). Aortic arch repair is difficult and postoperative complications are common. However, postoperative tracheobronchial stenosis with respiratory insufficiency is an uncommon complication and is usually caused by increased aortic anastomotic tension. We report here a case of tracheal compression by a mediastinal hematoma following IAA surgery. The patient underwent a repeat operation to remove the hematoma and was successfully weaned off the ventilator.In cases of tracheobronchial stenosis after aortic arch surgery, airway compression by increased aortic anastomotic tension is usually the first diagnosis considered by clinicians. Other causes, such as mediastinal hematomas, are often ignored. However, the severity of symptoms with mediastinal hematomas makes this an important entity.

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

    Science.gov (United States)

    Peng, M.; Zhang, L. M.

    2013-02-01

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

  1. Estimated strength of shear keys in concrete dams

    Energy Technology Data Exchange (ETDEWEB)

    Curtis, D.D. [Hatch Energy, Niagara Falls, ON (Canada); Lum, K.K.Y. [BC Hydro, Burnaby, BC (Canada)

    2008-07-01

    BC Hydro requested that Hatch Energy review the seismic stability of Ruskin Dam which was constructed in 1930 at Hayward Lake in British Columbia. The concrete gravity dam is founded nearly entirely on rock in a narrow valley. The vertical joints between blocks are keyed and grouted. The strength of the shear keys was assessed when a non-linear finite element model found that significant forces were being transferred laterally to the abutments during an earthquake. The lateral transfer of loads to the abutment relies on the strength of the shear keys. The dynamic finite element analysis was used to determine the stability of the dam. A review of the shear strength measurements reported in literature showed that the measurements compared well to those obtained by BC Hydro from cores taken from Ruskin Dam. The cohesive strength obtained using the Griffith failure criteria was also in good agreement with both sets of measurements. A simple ultimate shear strength equation was developed using the Mohr-Coulomb failure criteria to determine combined cohesive and frictional strength of shear keys. Safety factors of 2.0 for static loads and 1.5 for seismic loads were proposed to reduce the ultimate strength to allowable values. It was concluded that given the relatively high shear strength established for the shear keys, the abutment rock or dam/abutment contact will control the amount of load which can arch to the abutments. 8 refs., 4 tabs., 5 figs.

  2. Investigation of geophysical methods for assessing seepage and internal erosion in embankment dams : a study of through-dam seismic testing at WAC Bennett Dam

    Energy Technology Data Exchange (ETDEWEB)

    Gaffran, P.; Jeffries, M. [BC Hydro, Burnaby, BC (Canada)

    2005-07-15

    Crosshole tomography is used to establish the distribution of seismic velocity between drill holes. The through-dam mode takes advantage of the triangular cross-section of earth embankments, obviating the need for drill holes. Seismic energy, generated on one face of the dam, passes underneath the crest and is detected by sensors arrayed on the opposite face. The sinkholes discovered at WAC Bennett Dam in 1996 provided an opportunity to test the procedure. Using p-wave energy, two series of measurements were conducted, notably one immediately before remediation of one sinkhole, and a second one shortly after the sinkhole was repaired. The known defect was successfully imaged by the first round of measurements. This report presented the results of an investigation of the through-dam seismic method using propagation of seismic waves through a dam from upstream to downstream, or vice-versa. The purpose of the study was to determine if this procedure could characterize the distribution of seismic velocity within a dam in an accurate and cost effective manner. The report presented the methods of velocity testing such as crosshole and downhole, and tomography; and through-dam measurements. Background to the Bennett Dam studies was also provided, with particular reference to the Bennett Dam sinkholes; sinkhole investigations; working hypothesis for sinkhole development; sinkhole number one characterization; and sinkhole remediation. An analysis of compression wave testing at Bennett Dam and shear wave testing was then offered. Other topics that were discussed included field test procedures; methodologies for data processing; p-waves versus s-waves; applicability of the research; and costs of through-dam surveys. It was concluded that under the right circumstances, through-dam seismic testing was capable of detecting changed conditions in an embankment dam. 15 refs., 2 tabs., 41 figs., 1 appendix.

  3. Proceedings of the Canadian Dam Association's 2005 annual conference : 100 years of dam experience : balancing tradition and innovation. CD-ROM ed.

    International Nuclear Information System (INIS)

    2004-09-01

    This conference provided a forum to promote discussion on improving the management and safety of dams. It featured 8 technical sessions as well as workshops to discuss dam safety guidelines and guidelines for extreme flood analyses and their applications. It also featured workshops on instrumentation and performance monitoring of dams; tailing dam closures and reclamation; and, practical approaches to emergency preparedness for dam owners. The discussions provided details on large hydropower development projects, their innovations in environmental impact assessment, mitigation, and monitoring. The conference included a technical component led by experts on dams and tailings facilities. Recent developments in dam construction were reviewed along with discharge and debris management, tailings dam issues, asset management, seismic issues, public safety, seepage monitoring, flow control, dam rehabilitation, concrete testing, hydrotechnical issues, risk assessment methodology, and safety guidelines. All 24 presentations at this conference have been catalogued separately for inclusion in this database

  4. 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...

  5. Teton Dam failure

    Energy Technology Data Exchange (ETDEWEB)

    Snorteland, N. [United States Dept. of the Interior, Washington, DC (United States). Bureau of Reclamation

    2009-07-01

    This case summary discussed an internal erosion failure that occurred at the embankment foundation of Teton Dam. The project was designed as a run-of-the-river power generation facility and to provide irrigation, flood protection, and power generation to the lower Teton region of southern Idaho. The dam site was located next to the eastern Snake River plain, a volcanic filled depression. The foundation's cutoff trench was excavated into the bedrock along the length of the dam. The dam was designed as a zoned earthfill with a height of 305 feet. A trench made of low plasticity windblown silt was designed to connect the embankment core to the rock foundation. Seeps were noted in 1976, and a leak was observed near the toe of the dam. A wet spot appeared on the downstream face of the dam at elevation 5200. A sinkhole then developed. The embankment crest collapsed, and the dam breached. Peak outflow was estimated at 1,000,000 cfs. The failure was attributed to a lack of communication between designers, a failure to understand geologic information about the region, and an insufficient review of designs and specifications by designers and field personnel. No monitoring instrumentation was installed in the embankment. Approximately 300 square miles were inundated, and 25,000 people were displaced. Eleven people were killed. A review group noted that the rock surface was not adequately sealed, and that the dam failed as a result of inadequate protection of the impervious core material from internal erosion. 42 figs.

  6. Estimating flood inundation caused by dam failures

    Energy Technology Data Exchange (ETDEWEB)

    Mocan, N. [Crozier and Associates Inc., Collingwood, ON (Canada); Joy, D.M. [Guelph Univ., ON (Canada). School of Engineering; Rungis, G. [Grand River Conservation Authority, Cambridge, ON (Canada)

    2006-01-15

    Recent advancements in modelling inundation due to dam failures have allowed easier and more illustrative analyses of potential outcomes. This paper described new model and mapping capabilities available using the HEC-RAS hydraulic model in concert with geographic information systems (GIS). The study area was the upper reaches of Canagagigue Creek and the Woolwich Dam near Elmira, Ontario. A hydraulic analysis of a hypothetical dam failure was developed based on the summer probable maximum flood (PMF) event. Limits extended from Woolwich Dam to downstream of the Town of Elmira. An incoming summer PMF hydrograph was set as the upstream boundary condition in the upstream model. Simulation parameters include simulation time-step; implicit weighting factor; water surface calculation tolerance; and output calculation interval. Peak flows were presented, as well as corresponding flood inundation results through the Town of Elmira. The hydraulic model results were exported to a GIS in order to develop inundation maps for emergency management planning. Results from post-processing included inundation maps for each of the simulated time-steps as well as an inundation animation for the duration of the dam breach. It was concluded that the modelling tools presented in the study can be applied to other dam safety assessment projects in order to develop effective and efficient emergency preparedness plans through public consultation and the establishment of impact zones. 1 tab., 2 figs.

  7. Occlusal stability in shortened dental arches.

    NARCIS (Netherlands)

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

    2001-01-01

    Shortened dental arches consisting of anterior and premolar teeth have been shown to meet oral functional demands. However, the occlusal stability may be at risk as a result of tooth migration. The aim of this nine-year study was to investigate occlusal stability in shortened dental arches as a

  8. Occlusal stability in shortened dental arches.

    Science.gov (United States)

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

    2001-02-01

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

  9. Dental arch dimensions, form and tooth size ratio among a Saudi sample

    Directory of Open Access Journals (Sweden)

    Haidi Omar

    2018-01-01

    Full Text Available Objectives: To determine the dental arch dimensions and arch forms in a sample of Saudi orthodontic patients, to investigate the prevalence of Bolton anterior and overall tooth size discrepancies, and to compare the effect of gender on the measured parameters. Methods: This study is a biometric analysis of dental casts of 149 young adults recruited from different orthodontic centers in Jeddah, Saudi Arabia. The dental arch dimensions were measured. The measured parameters were arch length, arch width, Bolton’s ratio, and arch form. The data were analyzed using IBM SPSS software version 22.0 (IBM Corporation, New York, USA; this cross-sectional study was conducted between April 2015 and May 2016. Results: Dental arch measurements, including inter-canine and inter-molar distance, were found to be significantly greater in males than females (p less than 0.05. The most prevalent dental arch forms were narrow tapered (50.3% and narrow ovoid (34.2%, respectively. The prevalence of tooth size discrepancy in all cases was 43.6% for anterior ratio and 24.8% for overall ratio. The mean Bolton’s anterior ratio in all malocclusion classes was 79.81%, whereas the mean Bolton’s overall ratio was 92.21%. There was no significant difference between males and females regarding Bolton’s ratio. Conclusion: The most prevalent arch form was narrow tapered, followed by narrow ovoid. Males generally had larger dental arch measurements than females, and the prevalence of tooth size discrepancy was more in Bolton’s anterior teeth ratio than in overall ratio.

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

    Science.gov (United States)

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

    2008-04-01

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

  11. 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.

  12. 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.

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

    Science.gov (United States)

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

    2013-01-01

    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. 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. Lateral cephalogram and dental casts were obtained from 180 untreated South Indian adults (90 males and 90 females) above 18 year old with no cross bite, minimal crowding and spacing. The angle between the anterior cranial base and the mandibular plane was measured on lateral cephalogram of each patient. Dental casts were used to obtain comprehensive dental measurements including maxillary and mandibular inter canine, inter premolar and inter molar widths, as well as amount of crowding or spacing. The results showed that male arch widths were significantly larger than those of females (P population. The results obtained in our study when compared with studies done in other population groups showed that there is difference in inter arch widths according to ethnicity and race. It was concluded that the dental arch width is associated with gender, race and vertical facial morphology. Thus using individualized arch wires according to each patient's pre treatment arch form and width is suggested during orthodontic treatment.

  14. Semi-parametric estimation for ARCH models

    Directory of Open Access Journals (Sweden)

    Raed Alzghool

    2018-03-01

    Full Text Available In this paper, we conduct semi-parametric estimation for autoregressive conditional heteroscedasticity (ARCH model with Quasi likelihood (QL and Asymptotic Quasi-likelihood (AQL estimation methods. The QL approach relaxes the distributional assumptions of ARCH processes. The AQL technique is obtained from the QL method when the process conditional variance is unknown. We present an application of the methods to a daily exchange rate series. Keywords: ARCH model, Quasi likelihood (QL, Asymptotic Quasi-likelihood (AQL, Martingale difference, Kernel estimator

  15. Mycotic Aneurysm of the Aortic Arch

    Directory of Open Access Journals (Sweden)

    Ji Hye Seo

    2014-08-01

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

  16. Optimal graft diameter and location reduce postoperative complications after total arch replacement with long elephant trunk for arch aneurysm.

    Science.gov (United States)

    Kondoh, Haruhiko; Funatsu, Toshihiro; Toda, Koich; Kainuma, Satoshi; Kuki, Satoru; Taniguchi, Kazuhiro

    2011-08-01

    Total arch replacement with an elephant trunk is a standard treatment for arch aneurysm, but serious complications, such as paraplegia and peripheral embolization caused by flapping of the elephant trunk, remain. Moreover, dilation of the descending aorta and retrograde flow into the peri-graft space at the distal elephant trunk are frequent problems. We hypothesized that optimal graft diameter and location would reduce complications after total arch replacement with a long elephant trunk by achieving complete thrombosis and minimal dilation of the descending aorta around the elephant trunk. We treated 65 patients with arch aneurysm by total arch replacement with a long elephant trunk anastomosed at the base of the innominate artery. The graft diameter was undersized (10%-20% of the distal aorta's diameter). Elephant trunk length was determined by preoperative computed tomography to locate the distal end at Th6 to Th8. Thrombosis around the elephant trunk, diameter of the descending aorta, and distance between the descending aorta and the graft near the distal end of the elephant trunk were evaluated using computed tomography. The distal end of the elephant trunk was located at Th 8 ± 1. There were no operative deaths, 3 patients (5%) died in the hospital, and 3 patients (5%) experienced spinal cord injury, including 1 in whom permanent paraplegia developed. Computed tomography revealed complete thrombosis around the elephant trunk in 58 patients (89%). The descending aorta did not dilate further, and distance between the descending aorta and the graft progressively decreased. Optimal graft diameter and location minimized postoperative complications, with complete thrombosis and no dilation of the descending aorta around the long elephant trunk in most patients. Copyright © 2011 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  17. Investigation on the Causes of Cracking in Earth Dams (Case study: Mahmood-Abad Earth Dam

    Directory of Open Access Journals (Sweden)

    H. Rahimi

    2016-09-01

    Full Text Available Introduction: Cracking of earth dams is a one of the main threat causes of stability of embankment dams. In this research by modeling of the behavior of an embankment dam and employing conditions of the earthquake, the reasons of cracking were inspected using by modeling of earth dam behavior. Based on the literature, one of the main causes of dam failures is sliding and cracking of the dam structure during earthquake. Localized liquefaction of foundation soils was one of the causes of the observed post-earthquake distress within these dams. Material and Methods: In order to study the causes and the results of crack on earth dams, Mahmoodabad earthen dam with a height of 19 m, is located in Zanjan province, northwest of Iran, which suffered a longitudinal crack on the crest and slight sliding of the upstream slope due to 2001 Avaj earthquake was studied. This dam has faced earthquake two times with an interval of two years. During the first earthquake with the magnitude about 6.6 in Richter scale small longitudinal cracks had created on the crest. The developed cracks had been repaired by injecting the cement and then has been hidden by passing the time. After the second earthquake with the magnitude about 6.5 in Richter scale the hidden cracks had been appeared again and the slight movement of the upper slopes of dam reported. Based on the site investigation and documented information about dam, including maps and parameter data, the behavior of the dam has modeled by using Plaxis as a finite element model. In order to check the accuracy of the design of dam, the stability analysis has been conducted using by Xslope as a limit equilibrium model. The foundation conditions and the Geotechnical properties of the layer beneath the dam has been inspected by open excavation. Results and Discussion: Underground investigation about Geotechnical properties of dam foundation has showed that there is a thin sandy layer confined in alluvium material of the

  18. Small dams need better management

    Science.gov (United States)

    Balcerak, Ernie

    2012-03-01

    Many small dams around the world are poorly maintained and represent a safety hazard, according to Pisaniello et al. Better oversight of small dams is needed, the authors argue. The researchers reviewed literature, conducted case studies in four states in Australia, and developed policy benchmarks and best practices for small-dam management. Small dams, often just several meters high and typically privately owned by individual farmers, have historically caused major damage when they fail. For instance, in China in 1975, 230,000 people died when two large dams failed because of the cumulative failure of 60 smaller upstream dams. In the United States, in 1977 the 8-meter-high Kelly Barnes Lake dam failed, killing 39 people. Many other small-dam failures around the world have resulted in casualties and severe ecological and economic damage.

  19. Safety management of the Karapiro dam, New Zealand

    International Nuclear Information System (INIS)

    Everitt, S.C.

    1995-01-01

    The dam safety program for 36 hydraulic structures in New Zealand were presented, with special emphasis on the application of this program to the Karapiro dam. The management of the hazard presented by the dam was detailed, and the proposed solutions for its remediation were presented. Dynamic analysis was employed using an elastic 3-D finite element model, using actual earthquake time history records as an input, scaled to the required Maximum Credibility Earthquake (MCE). The results confirmed that the arch section of the Karapiro dam was satisfactory, as was the spillway block, provided that drainage was preserved, however, the left abutment and thrust block were considered unstable. Four options were proposed for strengthening the abutment: (1) lowering the groundwater, (2) installation of stresses anchors, (3) mass concrete buttressing upstream and/or downstream, and (4) installation of reinforced concrete shear keys. However, prior to undertaking any remediation work, rock mass properties and groundwater conditions should be re-investigated. 1 ref., 7 figs

  20. Accuracy Analysis of a Dam Model from Drone Surveys

    Science.gov (United States)

    Buffi, Giulia; Venturi, Sara

    2017-01-01

    This paper investigates the accuracy of models obtained by drone surveys. To this end, this work analyzes how the placement of ground control points (GCPs) used to georeference the dense point cloud of a dam affects the resulting three-dimensional (3D) model. Images of a double arch masonry dam upstream face are acquired from drone survey and used to build the 3D model of the dam for vulnerability analysis purposes. However, there still remained the issue of understanding the real impact of a correct GCPs location choice to properly georeference the images and thus, the model. To this end, a high number of GCPs configurations were investigated, building a series of dense point clouds. The accuracy of these resulting dense clouds was estimated comparing the coordinates of check points extracted from the model and their true coordinates measured via traditional topography. The paper aims at providing information about the optimal choice of GCPs placement not only for dams but also for all surveys of high-rise structures. The knowledge a priori of the effect of the GCPs number and location on the model accuracy can increase survey reliability and accuracy and speed up the survey set-up operations. PMID:28771185

  1. Accuracy Analysis of a Dam Model from Drone Surveys

    Directory of Open Access Journals (Sweden)

    Elena Ridolfi

    2017-08-01

    Full Text Available This paper investigates the accuracy of models obtained by drone surveys. To this end, this work analyzes how the placement of ground control points (GCPs used to georeference the dense point cloud of a dam affects the resulting three-dimensional (3D model. Images of a double arch masonry dam upstream face are acquired from drone survey and used to build the 3D model of the dam for vulnerability analysis purposes. However, there still remained the issue of understanding the real impact of a correct GCPs location choice to properly georeference the images and thus, the model. To this end, a high number of GCPs configurations were investigated, building a series of dense point clouds. The accuracy of these resulting dense clouds was estimated comparing the coordinates of check points extracted from the model and their true coordinates measured via traditional topography. The paper aims at providing information about the optimal choice of GCPs placement not only for dams but also for all surveys of high-rise structures. The knowledge a priori of the effect of the GCPs number and location on the model accuracy can increase survey reliability and accuracy and speed up the survey set-up operations.

  2. Accuracy Analysis of a Dam Model from Drone Surveys.

    Science.gov (United States)

    Ridolfi, Elena; Buffi, Giulia; Venturi, Sara; Manciola, Piergiorgio

    2017-08-03

    This paper investigates the accuracy of models obtained by drone surveys. To this end, this work analyzes how the placement of ground control points (GCPs) used to georeference the dense point cloud of a dam affects the resulting three-dimensional (3D) model. Images of a double arch masonry dam upstream face are acquired from drone survey and used to build the 3D model of the dam for vulnerability analysis purposes. However, there still remained the issue of understanding the real impact of a correct GCPs location choice to properly georeference the images and thus, the model. To this end, a high number of GCPs configurations were investigated, building a series of dense point clouds. The accuracy of these resulting dense clouds was estimated comparing the coordinates of check points extracted from the model and their true coordinates measured via traditional topography. The paper aims at providing information about the optimal choice of GCPs placement not only for dams but also for all surveys of high-rise structures. The knowledge a priori of the effect of the GCPs number and location on the model accuracy can increase survey reliability and accuracy and speed up the survey set-up operations.

  3. 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. PMID:27054319

  4. 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.

  5. 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.

  6. Assessment of the influence of jogging on the shape of female foot arches.

    Science.gov (United States)

    Maslon, Agata; Golec, Joanna; Szczygiel, Elzbieta; Czechowska, Dorota; Golec, Boguslaw

    2017-12-23

    Both walking and its faster, running, consist of cyclical subsequent phases of swing and support; however, they differ in their time proportions as well as magnitude of acting forces. There is a lack of studies concerning the long-term consequences of repeated jogging cycles on the function of feet and, above all, on their permanent impact on the shape of foot arches. The objective of this study was to answer the question whether regular jogging changes the shape of the transverse and medial longitudinal arches of the feet. The research material consisted of 96 women with an average age of 26.57, and included 50 actively jogging women, and 46 of non-joggers. The study was performed with the use of EMED-SF force platform. The plantar surface of the foot was divided into 10 regions according to Cavanagh, for which peak pressure and contact time were established. Two indicators were defined: metatarsal bone pressure distribution pattern acc. to Kantali, and longitudinal arch index acc. to Cavanagh. The data obtained revealed more frequent occurrence of the greatest pressure under the centrally located metatarsal heads (lack of functional foot transverse arch) among the female joggers, compared with the non-joggers. Moreover, the findings indicate the higher frequency of medial longitudinal foot arch flattening among female runners, with a great deal of consistency between both feet, whereas results for the control group show asymmetrical medial arch shapes with right foot propensity to normal arch shape and left foot tendency for excessive arch. The observed differences in feet arch shapes between female joggers and non-joggers indicate the influence of jogging on feet functional adaptations.

  7. 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

  8. Highly Tunable Electrothermally Actuated Arch Resonator

    KAUST Repository

    Hajjaj, Amal Z.; Ramini, Abdallah; Alcheikh, Nouha; Younis, Mohammad I.

    2016-01-01

    that after some electro-thermal voltage load, the third resonance frequency starts to become more sensitive to the axial thermal stress, while the first resonance frequency becomes less sensitive. These results can be used as guidelines to utilize arches

  9. Nonlinear Dynamics of Electrostatically Actuated MEMS Arches

    KAUST Repository

    Al Hennawi, Qais M.

    2015-01-01

    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

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

    Science.gov (United States)

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

    2008-10-01

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

  11. Highly Tunable Electrothermally Actuated Arch Resonator

    KAUST Repository

    Hajjaj, Amal Z.

    2016-12-05

    This paper demonstrates experimentally, theoretically, and numerically a wide-range tunability of electrothermally actuated MEMS arch beams. The beams are made of silicon and are intentionally fabricated with some curvature as in-plane shallow arches. Analytical results based on the Galerkin discretization of the Euler Bernoulli beam theory are generated and compared to the experimental data and results of a multi-physics finite-element model. A good agreement is found among all the results. The electrothermal voltage is applied between the anchors of the clamped-clamped MEMS arch beam, generating a current that passes through the MEMS arch beam and controls its axial stress caused by thermal expansion. When the electrothermal voltage increases, the compressive stress increases inside the arch beam. This leads to increase in its curvature, thereby increases the resonance frequencies of the structure. We show here that the first resonance frequency can increase up to twice its initial value. We show also that after some electro-thermal voltage load, the third resonance frequency starts to become more sensitive to the axial thermal stress, while the first resonance frequency becomes less sensitive. These results can be used as guidelines to utilize arches as wide-range tunable resonators.

  12. 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...... of a desired width. On top of the arch is a filling material to level out the surface of the above road. The filling only transfers vertical loads to the arch. The geometry and material properties of Super-Light Decks are presented, and we refer to several fullscale tests of Pearl-Chain arches where...... 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...

  13. Wynoochee Dam Foundation Report

    Science.gov (United States)

    1988-01-01

    schists and in propylitized andesite volcanic rocks. Tests on chlorite-bearing graywackes (Lumni Island and Robe Quarry, Seattle District) and... propylitized chlorite-bearing andesites (Blue River and Lookout Point Dams, Portland District) have shown these rocks to be durable materials with only minor

  14. The underwater installation of a drained geomembrane system on Lost Creek Dam

    International Nuclear Information System (INIS)

    Onken, S.; Harlan, R.C.; Wilkes, J.; Vaschetti, G.

    1998-01-01

    Lost Creek Dam was constructed in California around 1923. It is a 122 foot high concrete arch dam with a crest elevation of 3,287 feet and a crest length of 490 feet. Over the years, the dam and the condition of the concrete face have deteriorated. The concrete is porous and seeps water along the entire downstream face. In winter, the seeping water freezes, penetrates the concrete and causes expansion and spalling of the concrete surface. In some places, the concrete has very low strength to a depth of a foot or more, rendering the dam only marginally safe. Seven mitigative measures were identified as possible solutions to the problem. It was determined that the seepage of the water through the concrete dam could be stopped with the installation of a geomembrane to the upstream face. This paper describes the unique underwater installation of a drained geomembrane system on the concrete face of the dam. This was the first ever installation of a drained geomembrane system on an entire dam using divers. Monitoring will determine the success of the project, and whether the seepage of the water through the porous concrete had been reduced sufficiently to stop the deterioration of the concrete on the downstream face. 2 refs., 12 figs

  15. Dam Design can Impede Adaptive Management of Environmental Flows: A Case Study from the Opuha Dam, New Zealand

    Science.gov (United States)

    Lessard, JoAnna; Murray Hicks, D.; Snelder, Ton H.; Arscott, David B.; Larned, Scott T.; Booker, Doug; Suren, Alastair M.

    2013-02-01

    The Opuha Dam was designed for water storage, hydropower, and to augment summer low flows. Following its commissioning in 1999, algal blooms (dominated first by Phormidium and later Didymosphenia geminata) downstream of the dam were attributed to the reduced frequency and magnitude of high-flow events. In this study, we used a 20-year monitoring dataset to quantify changes associated with the dam. We also studied the effectiveness of flushing flows to remove periphyton from the river bed. Following the completion of the dam, daily maximum flows downstream have exceeded 100 m3 s-1 only three times; two of these floods exceeded the pre-dam mean annual flood of 203 m3 s-1 (compared to 19 times >100 m3 s-1 and 6 times >203 m3 s-1 in the 8 years of record before the dam). Other changes downstream included increases in water temperature, bed armoring, frequency of algal blooms, and changes to the aquatic invertebrate community. Seven experimental flushing flows resulted in limited periphyton reductions. Flood wave attenuation, bed armoring, and a shortage of surface sand and gravel, likely limited the effectiveness of these moderate floods. Floods similar to pre-dam levels may be effective for control of periphyton downstream; however, flushing flows of that magnitude are not possible with the existing dam infrastructure. These results highlight the need for dams to be planned and built with the capacity to provide the natural range of flows for adaptive management, particularly high flows.

  16. 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.

  17. Dam safety at Seven Sisters Generating Station

    International Nuclear Information System (INIS)

    Carson, R. W.; Gupta, R. C.

    1996-01-01

    A safety surveillance program for all hydraulic structures in Manitoba was first implemented in 1979, and updated in 1988. This contribution describes the current status of the program, and the nature of the issues that the program was designed to address. The Seven Sisters Station's dam on the Winnipeg River, about 90 km northeast of the City of Winnipeg, was used as an example. Extensive reviews of flood risks and downstream inundation potential at Seven Sisters' revealed a number of deficiencies; these findings will be incorporated into a corporate plan of overall remediation. Updating the program will also include efforts to ensure adherence to national dam safety guidelines. 5 figs

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

    International Nuclear Information System (INIS)

    Ahn, Kyung-Sik; Yong, Hwan Seok; Woo, Ok Hee; Kang, Eun-Young; Lee, Joo-Won

    2007-01-01

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

  19. Geotechnical sounding of the UTE-Uruguay dams; La auscultacion geotecnica de las presas de UTE

    Energy Technology Data Exchange (ETDEWEB)

    Patrone Matteo, Julio C.; Rosriguez Pastorino, Sandra; Mandia Bica, Magdalena [Administracion Nacional de Usinas e Transmisiones Electricas (UTE), Montevideo (Uruguay)]. E-mail: gsgh@ute.com.uy

    1998-07-01

    This paper addresses specifically to the soil dams, and soil dikes of the Constitucion Dam, which is presently the most instrumented, considering that the set of inspection routine and instrumentation data, including the interpretation and behaviour evaluation, are the basis for the dam sounding.

  20. Seen one dam, seen 'em all?: the surprising story of the Deschutes River.

    Science.gov (United States)

    Sally. Duncan

    2000-01-01

    In the next few decades, hundreds of private dams will be relicensed by the Federal Energy Regulatory Commission. Many of them are on or influence Forest Service lands. Relicensing requires rigorous technical assessments of the effects of dams on critical resources, including channels, aquatic habitat, water quality, and recreation. Dams differ widely in their...

  1. Footprint parameters as a measure of arch height.

    Science.gov (United States)

    Hawes, M R; Nachbauer, W; Sovak, D; Nigg, B M

    1992-01-01

    The human foot has frequently been categorized into arch height groups based upon analysis of footprint parameters. This study investigates the relationship between directly measured arch height and many of the footprint parameters that have been assumed to represent arch height. A total of 115 male subjects were measured and footprint parameters were calculated from digitized outlines. Correlation and regression analyses were used to determine the relationship between footprint measures and arch height. It may be concluded from the results that footprint parameters proposed in the literature (arch angle, footprint index, and arch index) and two further parameters suggested in this study (arch length index and truncated arch index) are invalid as a basis for prediction or categorization of arch height. The categorization of the human foot according to the footprint measures evaluated in this paper represent no more than indices and angles of the plantar surface of the foot itself.

  2. Thermal monitoring of leakage through Karkheh embankment dam, Iran

    Energy Technology Data Exchange (ETDEWEB)

    Mirghasemi, A.A.; Bagheri, S.M. [Tehran Univ., Tehran (Iran, Islamic Republic of). Dept. of Civil Engineering; Heidarzadeh, M. [Tehran Univ., Tehran (Iran, Islamic Republic of). Dept. of Civil Engineering]|[Mahab Ghodss Consulting Engineers, Tehran (Iran, Islamic Republic of)

    2007-07-01

    A newly developed and simple method for monitoring seepage in embankment dams was presented. The method of temperature measurement is based on the fact that a change in permeability results in a change in seepage flow, thereby causing a temperature change that can be readily measured in the dam body and foundation. In this study, water leaking through the Karkheh embankment dam was thermally analyzed to determine a pattern and amount of water seepage. With nearly 33 million cubic metres of fill, the Karkheh earth and rock-fill dam is the largest dam in Iran. Construction was completed in 2000. The thermal processes in the embankment were studied due to the dam's complex thermo-hydraulic behaviour. Thermal data was collected and analyzed during construction and operation of the dam. This paper presented the temperature variations for the different dam zones, including core, upstream shell, downstream shell, upstream filter, downstream filter and the plastic concrete cut-off wall. It was determined that the clay core works very well as an impermeable curtain. It was also shown that temperature variations of the Karkheh reservoir water is seasonal, and decrease as water depth increases. The reservoir water temperature remains constant beyond depths of 60 metres. The thermal behaviour of the core is not similar to that of the reservoir, indicating a very low value of seepage through the core. The pattern of temperature variations in the upstream shell in the left abutment is harmonic, while in the right abutment it is not harmonic. A harmonic pattern of temperature variation exists in some aquifers of the dam foundation, indicating high seepage through these aquifers. The Karkheh dam cut-off wall performs satisfactorily. It was determined that one dimensional equations for estimating seepage cannot be applied for the Karkheh dam. 17 refs., 11 figs.

  3. Expansion at Olympic Dam

    International Nuclear Information System (INIS)

    Lewis, C.

    1997-01-01

    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

  4. Complex atheromatosis of the aortic arch in cerebral infarction.

    Science.gov (United States)

    Capmany, Ramón Pujadas; Ibañez, Montserrat Oliveras; Pesquer, Xavier Jané

    2010-08-01

    In many stroke patients it is not possible to establish the etiology of stroke. However, in the last two decades, the use of transesophageal echocardiography in patients with stroke of uncertain etiology reveals atherosclerotic plaques in the aortic arch, which often protrude into the lumen and have mobile components in a high percentage of cases. Several autopsy series and retrospective studies of cases and controls have shown an association between aortic arch atheroma and arterial embolism, which was later confirmed by prospectively designed studies. The association with ischemic stroke was particularly strong when atheromas were located proximal to the ostium of the left subclavian artery, when the plaque was ≥ 4 mm thick and particularly when mobile components are present. In these cases, aspirin might not prevent adequately new arterial ischemic events especially stroke. Here we review the evidence of aortic arch atheroma as an independent risk factor for stroke and arterial embolism, including clinical and pathological data on atherosclerosis of the thoracic aorta as an embolic source. In addition, the impact of complex plaques (≥ 4 mm thick, or with mobile components) on increasing the risk of stroke is also reviewed. In non-randomized retrospective studies anticoagulation was superior to antiplatelet therapy in patients with stroke and aortic arch plaques with mobile components. In a retrospective case-control study, statins significantly reduced the relative risk of new vascular events. However, given the limited data available and its retrospective nature, randomized prospective studies are needed to establish the optimal secondary prevention therapeutic regimens in these high risk patients.

  5. First and second branchial arch syndromes: multimodality approach

    International Nuclear Information System (INIS)

    Senggen, Elodie; Laswed, Tarek; Meuwly, Jean-Yves; Maestre, Leonor Alamo; Meuli, Reto; Gudinchet, Francois; Jaques, Bertrand

    2011-01-01

    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.)

  6. Wheel arch aerodynamics of a modern road vehicle

    International Nuclear Information System (INIS)

    Apsley, S.; Aroussi, A.

    2003-01-01

    A geometrically faithful model of the Aston Martin V12 Vanquish was formed in 3D CAD and used to perform an extensive CFD study into the airflow in and around the wheel arch of the vehicle. Parameters such as spin ratio, ground clearance, vertical and horizontal insertion into the wheel arch and the yaw angles experienced during cornering, were all under investigation. The additional aim of the research was to validate or refute the use of CFD as a tool in this complex area of fluid flow. This research serves to highlight a number of problems and potential solutions in the use of CFD. Meshing problems can be eliminated with increased computational power and suggestions have been made to improve the modeling of rotating boundaries that include radial features such as wheel spokes. Much of the CFD data ties well with previously conducted experimental work, if not numerically then in trend. Without additional physical validation however, it is difficult to ascertain the overall accuracy and usefulness of the remaining results, which have not yet been conducted in physical reality. Despite its limitations, the use of CFD permitted an extensive analysis in a comparatively short length of time and served to highlight potential areas for increased scrutiny. As an example, results from the final yaw angle case drew attention to a potential concern for aerodynamic destabilisation of the vehicle during cornering, generating lift on the front arch of the car that is already lifted due to cornering forces and body roll. (author)

  7. 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.)

  8. Flood and rockslide mitigative measures for the concrete sections of the Daisy Lake Dam

    International Nuclear Information System (INIS)

    Pataky, T.J.

    1991-01-01

    Studies conducted under British Columbia Hydro's dam safety program during the early 1980s indicated that dam sections of the Daisy Lake Dam would be overtopped by the probable maximum flood (PMF) and by a postulated slide generated wave (SGW). It was considered that the overtopping by either of the events could cause several sections of the concrete dam to fall, thereby resulting in uncontrolled release of the reservoir. The criteria used for determining foundation strength parameters, static and SGW induced water pressures, effective uplift and the appropriate factors of safety are discussed. The results of the analyses for the original dam sections and the design and implementation of the selected remedial measures are also described. These measures included lowering the Wing Dam and Saddle Dam by about 2 m to increase the spillway capacity and the installation of 43 post-tensioned anchors in the various sections of the main concrete and Wing dams. 9 refs., 8 figs., 3 tabs

  9. Dam spills and fishes

    International Nuclear Information System (INIS)

    1996-01-01

    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.)

  10. Walden North Dam overtopping : emergency response and rehabilitation

    Energy Technology Data Exchange (ETDEWEB)

    Dyer, S. [FortisBC Inc., South Slocan, BC (Canada); McCreanor, J. [Acres International Ltd., Calgary, AB (Canada); Cronin, D.L.R.; Daw, D. [Acres International Ltd., Vancouver, BC (Canada)

    2004-09-01

    This paper described the events that led to the overtopping of the Walden North Dam during a heavy rainfall in June 2002, resulting in a breach around an abutment wall. The dam is part of a run-of-river hydro development on Cayoosh Creek near Lillooet, British Columbia. The Walden North Dam was a low, 46 meter wide concrete dam with a single radial gate. The dam overtopping was attributed to failure of the radial gate hoist. Prior to this event, the dam had been classified by the British Columbia Dam Safety Authorities as a high and then a low consequence category of failure. As facility managers, Aquila Networks Canada Ltd. established an immediate action plan to stabilize the situation and resume normal power production by applying the following priorities: (1) ensure safety of workers and the public, (2) limit further damage to the dam and other facilities, (3) ensure environmental protection, and (4) continue to operate the generation units. Local authorities were informed to evacuate a downstream campsite and environmental agencies were contacted along with safety regulators. Repairs included demolition of the damaged portion of the structure and construction a new two-bay gate/stoplog spillway and bridge. Construction was completed by September 2003 according to the requirements of the Department of Fisheries and Oceans for minimum flow, accurate control of fish flows and environmental monitoring of the stream area. 10 figs.

  11. Alteration of stream temperature by natural and artificial beaver dams.

    Science.gov (United States)

    Weber, Nicholas; Bouwes, Nicolaas; Pollock, Michael M; Volk, Carol; Wheaton, Joseph M; Wathen, Gus; Wirtz, Jacob; Jordan, Chris E

    2017-01-01

    Beaver are an integral component of hydrologic, geomorphic, and biotic processes within North American stream systems, and their propensity to build dams alters stream and riparian structure and function to the benefit of many aquatic and terrestrial species. Recognizing this, beaver relocation efforts and/or application of structures designed to mimic the function of beaver dams are increasingly being utilized as effective and cost-efficient stream and riparian restoration approaches. Despite these verities, the notion that beaver dams negatively impact stream habitat remains common, specifically the assumption that beaver dams increase stream temperatures during summer to the detriment of sensitive biota such as salmonids. In this study, we tracked beaver dam distributions and monitored water temperature throughout 34 km of stream for an eight-year period between 2007 and 2014. During this time the number of natural beaver dams within the study area increased by an order of magnitude, and an additional 4 km of stream were subject to a restoration manipulation that included installing a high-density of Beaver Dam Analog (BDA) structures designed to mimic the function of natural beaver dams. Our observations reveal several mechanisms by which beaver dam development may influence stream temperature regimes; including longitudinal buffering of diel summer temperature extrema at the reach scale due to increased surface water storage, and creation of cool-water channel scale temperature refugia through enhanced groundwater-surface water connectivity. Our results suggest that creation of natural and/or artificial beaver dams could be used to mitigate the impact of human induced thermal degradation that may threaten sensitive species.

  12. Complex branchial fistula: a variant arch anomaly.

    Science.gov (United States)

    De Caluwé, D; Hayes, R; McDermott, M; Corbally, M T

    2001-07-01

    A 5-year-old boy presented with an infected left-sided branchial fistula. Despite antibiotic treatment and repeated excision of the fistula, purulent discharge from the wound persisted. Three-dimensional computed tomography (3D CT) reconstruction greatly facilitated the diagnosis and management of this case by showing the course of the fistulous tract. The complexity of the tract suggests that this represents a variant arch anomaly because it contains features of first, second, third, and fourth arch remnants. Copyright 2001 by W.B. Saunders Company.

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

    Science.gov (United States)

    Rounds, Stewart A.

    2010-01-01

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

  14. The socio-economics dynamics of Dam on Rural Communities: A case study of Oyan Dam, Nigeria

    Science.gov (United States)

    Ayeni, Amidu; Ojifo, Lawrence

    2018-06-01

    Dams construction and operations have many benefits, nevertheless, they have also led to lots of negative social, health and human impacts. It is based on this that this study assesses the potential and socio-economics dynamics of Oyan dam between 1980 and 2016. The data used for this study include water level and discharge records of the dam between 2007 and 2016, Landsat imageries of 1984 and 2016 and socio-economic datasets for the period. Analysis of the dam potentials (water supply, agriculture and hydropower) and socio-economic impacts of the dam were carried out using basic statistical tools, land use change anaysis and field survey using questionnaire, structured interview with major stakeholders and personal observation. The results revealed that the water level and storage of the Oyan dam had a relative reduction of about 2 % as well as non-stationarity pattern of water abstraction and production for the period. The landuse classes show all classes decreased in extent except the cultivated landuse that acrued an increased of 19.9 % between 1984 and 2016. Furthermore, commercial water supply varied significantly between 2010 and 2016 while irrigation scheme is grossly under-utilized from the inception in 1983 to 2016. Finally, the result of socio-economic impacts revealed that majority of the selected communities' members are actually not benefiting from the dam and their livelihoods are not from the dam.

  15. Odelouca Dam Construction: Numerical Analysis

    OpenAIRE

    Brito, A.; Maranha, J. R.; Caldeira, L.

    2012-01-01

    Odelouca dam is an embankment dam, with 76 m height, recently constructed in the south of Portugal. It is zoned with a core consisting of colluvial and residual schist soil and with soil-rockfill mixtures making up the shells (weathered schist with a significant fraction of coarse sized particles). This paper presents a numerical analysis of Odelouca Dam`s construction. The material con-stants of the soil model used are determined from a comprehensive testing programme carried out in the C...

  16. Health impacts of large dams

    International Nuclear Information System (INIS)

    Lerer, L.B.

    1999-01-01

    Large dams have been criticized because of their negative environmental and social impacts. Public health interest largely has focused on vector-borne diseases, such as schistosomiasis, associated with reservoirs and irrigation projects. Large dams also influence health through changes in water and food security, increases in communicable diseases, and the social disruption caused by construction and involuntary resettlement. Communities living in close proximity to large dams often do not benefit from water transfer and electricity generation revenues. A comprehensive health component is required in environmental and social impact assessments for large dam projects

  17. Hypothermia and Selective Antegrade Cerebral Perfusion Is Safe for Arch Repair in Type A Dissection.

    Science.gov (United States)

    Keeling, W Brent; Leshnower, Bradley G; Hunting, John C; Binongo, Jose; Chen, Edward P

    2017-09-01

    Unilateral selective antegrade cerebral perfusion with moderate hypothermic circulatory arrest has been shown to be a safe and effective method of cerebral protection during surgery for acute type A dissection. This study evaluates the impact of this cerebral protection strategy on clinical outcomes after extended aortic arch reconstruction in patients undergoing emergent repair of acute type A dissection. A retrospective review from 2004 to 2016 at a US academic center of patients undergoing surgery for acute type A dissections using moderate hypothermic circulatory arrest and selective antegrade cerebral perfusion was performed. Patient data were abstracted from The Society of Thoracic Surgeons (STS) institutional database and patient charts. Cohorts were established based on extent of arch replacement: a hemiarch group and a transverse arch group were created. Owing to a dearth of events, a risk score was estimated using a logistic regression model with 30-day mortality as outcome and preoperative variables as predictors, including non-STS variables such as malperfusion. Postoperative outcomes were then adjusted in subsequent regression analyses for the estimated risk score. In all, 342 patients met inclusion criteria and were included for analysis (299 hemiarch, 43 transverse arch). The mean age was 55.4 years and not different between groups (p = 0.79). Preoperative comorbidities, including prior stroke, diabetes mellitus, and renal failure, were also similar between groups (p > 0.2). Inhospital mortality was 11.7% for the entire cohort (11.7% hemiarch, 9.3% transverse arch; p = 0.60), and the permanent stroke rate was 7.3% (7.7% hemiarch, 4.3% transverse arch; p = 0.47). Median circulatory arrest time was 38.9 ± 19.2 minutes (35.0 ± 13.2 hemiarch, 65.1 ± 30.1 transverse arch; p optimal strategy for cerebral protection in this acute setting. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  18. GIS inundation mapping and dam breach analysis of Woolwich Dam using HEC-geoRAS

    Energy Technology Data Exchange (ETDEWEB)

    Mocan, N. [Crozier and Associates Inc., Collingwood, ON (Canada); Joy, D.M. [Guelph Univ., ON (Canada); Rungis, G. [Grand River Conservation Authority, Cambridge, ON (Canada)

    2006-07-01

    A study was conducted to determine the extent of flood inundation given a hypothetical dam breach scenario of the Woolwich Dam located in the Grand River Watershed, 2.5 km north of the Town of Elmira, Ontario. The dam is operated by the Grand River Conservation Authority and was constructed to provide low-flow augmentation to Canagagigue Creek. Advances in the computational capabilities of numerical models along with the availability of fine resolution geospatial data has lead to significant advances in the evaluation of catastrophic consequences due to the ensuing flood waters when dams fail. The hydraulic models HEC-RAS and HEC-GeoRAS were used in this study along with GIS to produce high resolution spatial and temporal flood inundation mapping. Given the proximity to the Town of Elmira, the dam is classified as having a high hazard potential. The large size and high hazard potential of the dam suggests that the Inflow Design Flood (IDF) is the Probable Maximum Flood (PMF) event. The outlet structure of the spillway consists of 4 ogee-type concrete spillways equipped with radial gates. A low-level concrete pipe located within the spillway structure provides spillage for maintenance purposes. The full flow capacity of the spillway structure is 297 cubic metres per second at the full supply level of 364.8 metres. In addition to GIS flood inundation maps, this paper included the results of flood hydrographs, water surface profiles and peak flow data. It was concluded that techniques used in this analysis should be considered for use in the development of emergency management planning and dam safety assessments across Canada. 6 refs., 3 tabs., 4 figs.

  19. Dam Break Analysis of Embankment Dams Considering Breach Characteristics

    Directory of Open Access Journals (Sweden)

    Abolfazl Shamsaei

    2004-05-01

    Full Text Available The study of dam's break, needs the definition of various parameters such as the break cause, its type, its dimension and the duration of breach development. The precise forecast for different aspects of the breach is one of the most important factors for analyzing it in embankment dam. The characteristics of the breach and determination of their vulnerability has the most effect on the waves resulting from dam break. Investigating, about the parameters of the breach in "Silveh" earth dam have been determined using the suitable model. In Silve dam a trapezoid breach with side slope z=0.01m and the average base line b=80m was computed. The duration of the breaches development is 1.9 hour. Regarding the above results and the application of DAM Break software the consequences of the probable break of the dam was determined. The analysis of the results of water covering of the city of Piranshahr located 12km from silve dam confirms that in 3 hours the water will reach the height (level of 1425 meters.

  20. A Modified Transpalatal Arch with Sleeve

    Directory of Open Access Journals (Sweden)

    Ashish Gupta

    2013-01-01

    Full Text Available Conventionally fabricated transpalatal arches often create deep grooves on the tongue causing discomfort to the patients. To ovecome this situation a modification has been devised which requires only a few minutes of lab time, thus enhancing patient′s compliance toward treatment.

  1. 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 ...

  2. Dam construction in salt rock

    International Nuclear Information System (INIS)

    Stockmann, N.; Beinlich, A.; Flach, D.; Jockwer, N.; Klarr, K.; Krogmann, P.; Miehe, R.; Schmidt, M.W.; Schwaegermann, H.F.; Walter, F.; Yaramanci, U.

    1991-11-01

    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) [de

  3. Methodical Design of Software Architecture Using an Architecture Design Assistant (ArchE)

    Science.gov (United States)

    2005-04-01

    PA 15213-3890 Methodical Design of Software Architecture Using an Architecture Design Assistant (ArchE) Felix Bachmann and Mark Klein Software...DATES COVERED 00-00-2005 to 00-00-2005 4. TITLE AND SUBTITLE Methodical Design of Software Architecture Using an Architecture Design Assistant...important for architecture design – quality requirements and constraints are most important Here’s some evidence: If the only concern is

  4. Neonatal aortic arch reconstruction avoiding circulatory arrest and direct arch vessel cannulation.

    Science.gov (United States)

    Tchervenkov, C I; Korkola, S J; Shum-Tim, D; Calaritis, C; Laliberté, E; Reyes, T U; Lavoie, J

    2001-11-01

    Aortic arch reconstruction in neonates routinely requires deep hypothermic circulatory arrest. We reviewed our experience with techniques of continuous low-flow cerebral perfusion (LFCP) avoiding direct arch vessel cannulation. Eighteen patients, with a median age of 11 days (range 1 to 85 days) and a mean weight of 3.2 +/- 0.8 kg, underwent aortic arch reconstruction with LFCP. Seven had biventricular repairs with arch reconstruction, 9 underwent the Norwood operation and 2 had isolated arch repairs. In 1 Norwood and 7 biventricular repair patients, LFCP was maintained by advancing the cannula from the distal ascending aorta into the innominate artery. In 8 of 9 Norwood patients, LFCP was maintained by directing the arterial cannula into the pulmonary artery confluence and perfusing the innominate artery through the right modified Blalock-Taussig shunt fully constructed before cannulation for cardiopulmonary bypass. In 2 patients requiring isolated arch reconstruction, the ascending aorta was cannulated and the cross-clamp was applied just distal to the innominate artery. LFCP was maintained at 0.6 +/- 0.2 L x min(-1) x m(-2) for 41.0 +/- 13.9 minutes at 18.5 degrees C +/- 1.1 degrees C. In 10 of the 18 patients, blood pressure during LFCP was 15 +/- 8 mm Hg remote from the innominate artery (left radial, umbilical or femoral arteries). In 8 of the 18 patients, right radial pressure during LFCP was 24 +/- 10 mm Hg. The mean mixed-venous saturation was 79.8% +/- 10% during LFCP. Two patients had preoperative seizures, whereas none had seizures postoperatively. One patient died. Neonatal aortic arch reconstruction is possible without circulatory arrest or direct arch vessel cannulation. These techniques maintained adequate mixed-venous oxygen saturations with no associated adverse neurologic outcomes.

  5. Evaluatie Dam tot Damloop 2014

    NARCIS (Netherlands)

    Deutekom-Baart de la Faille, Marije

    In het weekend van 20 en 21 september 2014 vond de 30ste editie van de Dam tot Damloop plaats. Onderzoekers van de Hogeschool van Amsterdam en Hogeschool Inholland hebben bij de Dam tot Damloop een evaluatieonderzoek uitgevoerd met als doel het vinden van aanknopingspunten voor het structureel

  6. War damages and reconstruction of Peruca dam

    International Nuclear Information System (INIS)

    Nonveiller, E.; Sever, Z.

    1999-01-01

    The paper describes the heavy damages caused by blasting in the Peruca rockfill dam in Croatia in January 1993. Complete collapse of the dam by overtopping was prevented through quick action of the dam owner by dumping clayey gravel on the lowest sections of the dam crest and opening the bottom outlet of the reservoir, thus efficiently lowering the water level. After the damages were sufficiently established and alternatives for restoration of the dam were evaluated, it was decided to construct a diaphragm wall through the damaged core in the central dam part as the impermeable dam element and to rebuild the central clay core at the dam abutments. Reconstruction works are described

  7. Surgical modification for preventing a gothic arch after aortic arch repair without the use of foreign material.

    Science.gov (United States)

    Seo, Dong-Man; Park, Jiyoung; Goo, Hyun Woo; Kim, Young Hwue; Ko, Jae-Kon; Jhang, Won Kyoung

    2015-04-01

    Systemic hypertension is the main late complication after arch reconstruction in patients with arch obstruction. Gothic arch geometry is suspected to be one of its possible causes. Accordingly, we evaluated here if a modified arch repair technique using an autologous pulmonary patch is effective in preventing gothic arch development. Fifty infants who underwent arch repair with either a modified (n = 17) or conventional (n = 33) technique between January 2006 and August 2012 by a single surgeon were retrospectively reviewed. Arch geometry was compared using three categories (gothic, crenel or roman), classified by the height/width (H/W) ratio and the arch angle measured in computed tomography. No gothic arch geometry was observed in the modified group, whereas it was observed in 9 cases in the conventional group (P = 0.005). Moreover, reintervention for arch restenosis was performed only in the conventional group (n = 4; P = 0.29). No associated complications were observed, although the selective cerebral perfusion time was longer in the modified group than in the conventional group (28.5 ± 6.2 vs 17.1 ± 9.9 min; P gothic arch geometry, but also as equally safe in terms of early clinical outcomes as conventional arch reconstruction techniques. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  8. Dam-break studies for mine tailings impoundments

    International Nuclear Information System (INIS)

    Jeyapalan, J.K.

    1982-01-01

    This paper describes simple procedures for performing dam-break analyses. Tailings from dam failures usually liquefy and flow for substantial distances as a viscous fluid. The prediction of the possible extent of flow slide movement is illustrated using two case histories. Topics considered include the flow behavior of liquefied talings, dimensionsless numbers for mine tailings and associated flow regimes, laminar flow, and turbulent flow. The potential inundation regions downstream of mine tailings dams are assessed. It is concluded that instances of flow slides of mine waste embankments indicate that the failure of these structures has considerable potential for damage to life and property in many cases

  9. Report on Auscultation of the Arenal's Dam P. H. Arenal

    International Nuclear Information System (INIS)

    1994-09-01

    The Costa Rican Electricity Institute (Instituto Costarricense de Electricidad), always has been worried to verify the good state of the works and thus to guarantee its operation. For that reason, it has established different sorts of auscultation to the Arenal's Dam. This report analyzes the geo-hydraulic, structural and topographic auscultation. It also includes information about the new techniques used by the ARCAL XVIII RLA/8/018; application of Tracer Techniques for the study of water leakage in dams and damming projects. (author). 18 charts, 2 maps, 4 tabs

  10. 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.

  11. Optimum design of large span concrete filled steel tubular arch bridge based on static, stability and modal analysis

    Institute of Scientific and Technical Information of China (English)

    赵长军; 胡隽; 徐兴

    2002-01-01

    A three-dimensional finite element model was established for a large span concrete filled steel tubular (CFST) arch bridge which is currently under construction. The arch rib, the spandrel columns, the prestressed concrete box-beam, the cast-in-situ concrete plate of bridge deck, the steel box-beam and the crossbeams connecting the two pieces of arch ribs, were modeled by three-dimensional Timoshenko beam elements (3DTBE). The suspenders were modeled by three-dimensional cable elements (3DCE). Both geometric nonlinearity and prestress effect could be included in each kind of element. At the same time a second finite element model with the same geometric and material properties excepted for the sectional dimension of arch rib was set up. Static dynamic analyses were performed to determine the corresponding characteristics of the structure. The results showed that the arch rib's axial rigidity could be determined by static analysis. The stability and vibration of this system could be separated into in-plane modes, out-of-plane modes and coupled modes. The in-plane stability and dynamic characteristics are determined by the arch rib's vertical stiffness and that of out-of-plane is determined by the crossbeams' stiffness and arch rib's lateral stiffness mainly. The in-plane stiffness is much greater than that of out-of-plane for this kind of bridge . The effect of geometric nonlinearity and prestress effect on bridge behavior is insignificant.

  12. Responses of riparian reptile communities to damming and urbanization

    Science.gov (United States)

    Hunt, Stephanie D.; Guzy, Jacquelyn C.; Price, Steven J.; Halstead, Brian J.; Eskew, Evan A.; Dorcas, Michael E.

    2013-01-01

    Various anthropogenic pressures, including habitat loss, threaten reptile populations worldwide. Riparian zones are critical habitat for many reptile species, but these habitats are also frequently modified by anthropogenic activities. Our study investigated the effects of two riparian habitat modifications-damming and urbanization-on overall and species-specific reptile occupancy patterns. We used time-constrained search techniques to compile encounter histories for 28 reptile species at 21 different sites along the Broad and Pacolet Rivers of South Carolina. Using a hierarchical Bayesian analysis, we modeled reptile occupancy responses to a site's distance upstream from dam, distance downstream from dam, and percent urban land use. The mean occupancy response by the reptile community indicated that reptile occupancy and species richness were maximized when sites were farther upstream from dams. Species-specific occupancy estimates showed a similar trend of lower occupancy immediately upstream from dams. Although the mean occupancy response of the reptile community was positively related to distance downstream from dams, the occupancy response to distance downstream varied among species. Percent urban land use had little effect on the occupancy response of the reptile community or individual species. Our results indicate that the conditions of impoundments and subsequent degradation of the riparian zones upstream from dams may not provide suitable habitat for a number of reptile species.

  13. Estimates o the risks associated with dam failure

    Energy Technology Data Exchange (ETDEWEB)

    Ayyaswamy, P.; Hauss, B.; Hseih, T.; Moscati, A.; Hicks, T.E.; Okrent, D.

    1974-03-01

    The probabilities and potential consequences of dam failure in California, primarily due to large earthquakes, was estimated, taking as examples eleven dams having a relatively large population downstream. Mortalities in the event of dam failure range from 11,000 to 260,000, while damage to property may be as high as $720 million. It was assumed that an intensity IX or X earthquake (on the Modified Mercalli Scale) would be sufficient to completely fail earthen dams. Predictions of dam failure were based on the recurrence times of such earthquakes. For the dams studied, the recurrence intervals for an intensity IX earthquake varied between 20 and 800 years; for an intensity X between 50 and 30,000 years. For the Lake Chabot and San Pablo dams (respectively 20, 30 years recurrent earthquake times for a intensity X) the associated consequences are: 34,000 (Lake Chabot) and 30,000 (San Pablo) people killed; damage $140 million and $77 million. Evaculation was found to ameliorate the consequences slightly in most cases because of the short time available. Calculations are based on demography, and assume 10 foot floodwaters will drown all in their path and destroy all one-unit homes in the flood area. Damage estimates reflect losses incurred by structural damage to buildings and do not include loss of income. Hence the economic impact is probably understated.

  14. Dynamic analyzing procedures adopted for concrete-faced rockfill dams in Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Tosun, H. [Dam Safety Association, Ankara (Turkey); Tosun, K. [TVT Hydrotech Bureau, Ankara (Turkey)

    2008-07-01

    A concrete faced rockfill dam (CFRD) has some advantages compared to other embankment types. The advantages include minimal settlement problems through the use of compacted rockfill; increased overall stability of the dam since the water pressure acts on the upstream face; and pore water pressure does not develop in the rockfill zone if it is well designed and constructed. It is thought that well-compacted CFRD has a high resistance to earthquake loading, as based on several factors including acceptable past performance of similar dams. While numerical solutions performed for this type of dams indicate that it is as safe as other embankment dams, their behavior is still questionable when they are subjected to severe seismic loading. This paper outlined the key principals of the dynamic analyzing method adopted for CFRDs in Turkey and summarized the practice of CFRDs with heights ranging from 54 to 135 metres throughout the country. Two-dimensional finite element models were executed to estimate displacements on the crest under the different loadings of earthquake. Dams that were discussed included the Kurtun Dam, the Torul Dam, the Atasu Dam, the Dim Dam, the Gordes Dam, and the Marmaris Dam. The paper also discussed the limitation about permanent settlement provided in the national dam specification and introduced the results obtained from a case study of the Pamukluk Dam located in southern Turkey. Geology and geotechnics as well as the embankment details and materials were discussed. The case study also summarized the selection of seismic parameters and dynamic analyses. 35 refs., 1 tab., 8 figs.

  15. A study on occlusal stability in shortened dental arches.

    Science.gov (United States)

    Sarita, Paulo T N; Kreulen, Cees M; Witter, Dick J; van't Hof, Martin; Creugers, Nico H J

    2003-01-01

    The aim of this study was to verify the hypothesis that shortened dental arches constitute a risk to occlusal stability. Using cluster samples, 725 subjects with shortened dental arches comprising intact anterior regions and zero to eight occluding pairs of posterior teeth and 125 subjects with complete dental arches were selected. Subjects with shortened dental arches were classified into eight categories according to arch length and symmetry. Parameters for occlusal stability were interdental spacing, occlusal tooth wear, occlusal contact of incisors in intercuspal position, and vertical and horizontal overlap. Additionally, tooth mobility and overeruption of unopposed teeth were assessed. Influence of independent variables (dental arch category, age, gender, and residence) on the parameters for occlusal stability was assessed by one-way ANOVA and Tukey's multiple range tests. Extreme shortened dental arches (zero to two pairs of occluding premolars) had significantly more interdental spacing, occlusal contact of incisors, and vertical overlap compared to complete dental arches. Occlusal wear and prevalence of mobile teeth were highest in these categories. The category with three to four occluding premolars had significantly more interdental spacing and, for the older age group, more anterior teeth in occlusal contact compared to complete dental arches. Age was consistently associated with increased changes in occlusal integrity. Signs of increased risk to occlusal stability seemed to occur in extreme shortened dental arches, whereas no such evidence was found for intermediate categories of shortened dental arches.

  16. Large dams and alluvial rivers in the Anthropocene: The impacts of the Garrison and Oahe Dams on the Upper Missouri River

    Science.gov (United States)

    Skalak, Katherine; Benthem, Adam J.; Schenk, Edward R.; Hupp, Cliff R.; Galloway, Joel M.; Nustad, Rochelle A.; Wiche, Gregg J.

    2013-01-01

    The Missouri River has had a long history of anthropogenic modification with considerable impacts on river and riparian ecology, form, and function. During the 20th century, several large dam-building efforts in the basin served the needs for irrigation, flood control, navigation, and the generation of hydroelectric power. The managed flow provided a range of uses, including recreation, fisheries, and habitat. Fifteen dams impound the main stem of the river, with hundreds more on tributaries. Though the effects of dams and reservoirs are well-documented, their impacts have been studied individually, with relatively little attention paid to their interaction along a river corridor. We examine the morphological and sedimentological changes in the Upper Missouri River between the Garrison Dam in ND (operational in 1953) and Oahe Dam in SD (operational in 1959). Through historical aerial photography, stream gage data, and cross sectional surveys, we demonstrate that the influence of the upstream dam is still a major control of river dynamics when the backwater effects of the downstream reservoir begin. In the “Anthropocene”, dams are ubiquitous on large rivers and often occur in series, similar to the Garrison Dam Segment. We propose a conceptual model of how interacting dams might affect river geomorphology, resulting in distinct and recognizable morphologic sequences that we term “Inter-Dam sequence” characteristic of major rivers in the US.

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

    Directory of Open Access Journals (Sweden)

    Leng Fei

    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.

  18. Olympic Dam Operations

    International Nuclear Information System (INIS)

    Crew, R.J.

    1992-01-01

    The Olympic Dam copper-uranium-gold-silver deposit in South Australia was discovered in 1975. The Mine is located 520 kilometres NNW of Adelaide, in South Australia. Following a six year period of intensive investigation and assessment of all the aspects required for the development of the deposit, the Joint Venturers decided in December, 1985, to proceed with the project. Milling of ore commenced in June 1988 and final products are cathode copper, uranium ore concentrate (yellow cake), and refined gold and silver. Anticipated production, from treating approximately 1.5 million tonnes of ore, in normal production years, is expected to be 45,000 tonnes of copper, 1,600 tonnes of yellow cake (1350 tonnes of Uranium), 25,000 ounces of gold and 500,000 ounces of silver. (orig./HP) [de

  19. Rehabilitation at Olympic Dam

    International Nuclear Information System (INIS)

    Chandler, W.P.; Middleton, B.A.

    1986-01-01

    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. 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.

  1. Miniscrew-assisted rapid palatal expansion for managing arch perimeter in an adult patient

    Directory of Open Access Journals (Sweden)

    Amanda Carneiro da Cunha

    Full Text Available ABSTRACT Introduction: Etiology of dental crowding may be related to arch constriction in diverse dimensions, and an appropriate manipulation of arch perimeter by intervening in basal bone discrepancies cases, may be a key for crowding relief, especially when incisors movement is limited due to underlying pathology, periodontal issues or restrictions related to soft tissue profile. Objectives: This case report illustrates a 24-year old woman, with maxillary transverse deficiency, upper and lower arches crowding, Class II, division 1, subdivision right relationship, previous upper incisors traumatic episode and straight profile. A non-surgical and non-extraction treatment approach was feasible due to the miniscrew-assisted rapid palatal expansion technique (MARPE. Methods: The MARPE appliance consisted of a conventional Hyrax expander supported by four orthodontic miniscrews. A slow expansion protocol was adopted, with an overall of 40 days of activation and a 3-month retention period. Intrusive traction miniscrew-anchored mechanics were used for correcting the Class II subdivision relationship, managing lower arch perimeter and midline deviation before including the upper central incisors. Results: Post-treatment records show an intermolar width increase of 5 mm, bilateral Class I molar and canine relationships, upper and lower crowding resolution, coincident dental midlines and proper intercuspation. Conclusions: The MARPE is an effective treatment approach for managing arch-perimeter deficiencies related to maxillary transverse discrepancies in adult patients.

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

    Directory of Open Access Journals (Sweden)

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

    2012-03-01

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

  3. Imaging findings in the right aortic arch with mirror image branching of arch vessels: An unusual cause of dysphagia

    Directory of Open Access Journals (Sweden)

    Guneet Singh

    2015-01-01

    Full Text Available We report a case of a 72-year-old female with a right aortic arch with mirror-image branching of arch vessels presenting with dysphagia, and characteristic images on barium esophagogram, contrast-enhanced computed tomography scan, and magnetic resonance aortography. Right-sided thoracic aortic arch with mirror-image branching of the brachiocephalic vessels causing dysphagia without associated congenital cardiac anomalies is extremely uncommon. Right-sided aortic arch is a rare congenital abnormality with incidence of 0.05-0.1% in the normal population. Anomalies of great vessels are usually incidental findings, because they are asymptomatic. Right aortic arch infrequently presents with a vascular ring that can cause complete or partial obstruction of the trachea and/or esophagus. The understanding of this arch anomaly is based on Edward′s hypothesis about the double arch system during embryonic developmental.

  4. Environmental Risk Assessment System for Phosphogypsum Tailing Dams

    OpenAIRE

    Xin Sun; Ping Ning; Xiaolong Tang; Honghong Yi; Kai Li; Lianbi Zhou; Xianmang Xu

    2013-01-01

    This paper may be of particular interest to the readers as it provides a new environmental risk assessment system for phosphogypsum tailing dams. In this paper, we studied the phosphogypsum tailing dams which include characteristics of the pollution source, environmental risk characteristics and evaluation requirements to identify the applicable environmental risk assessment methods. Two analytical methods, that is, the analytic hierarchy process (AHP) and fuzzy logic, were used to handle the...

  5. Anatomical Study of Healthy Aortic Arches.

    Science.gov (United States)

    Girsowicz, Elie; Georg, Yannick; Lefebvre, François; Lejay, Anne; Thaveau, Fabien; Roy, Catherine; Ohana, Mickael; Chakfe, Nabil

    2017-10-01

    With the steady increase of endovascular procedures involving the aortic arch (AA), an actual depiction of its anatomy has become mandatory. It has also become necessary to evaluate the natural evolution of the AA morphology as part of the evaluation of endovascular devices durability. The objective of this study was to perform a morphological and anatomical study of the AA and of the supra aortic trunks (SAT) in healthy patients, with an evaluation of their evolution with time, with a specific orientation applied to endovascular therapies of the AA. Sixty-one patients (31 men, mean age 50.8 [18-82]) with a normal anatomy were included in the study. Measurements included the diameters of the AA and SAT in 17 locations, their distance and angulation based on computed tomography angiography data. Statistical analysis focused on descriptive statistics, differences between genders, as well as correlations with age. Aortic diameters (mean ± SD) were 29.5 ± 3.9 mm at the ascending aorta, 28.6 ± 3.9 mm at the innominate artery (IA), 27.1 ± 3.2 mm at the left common carotid artery (LCCA), 25.3 ± 3.0 mm at the left subclavian artery (LSCA), 23.9 ± 3.3 mm at the descending aorta. Mean angulation of the AA was 82° (95% confidence interval [CI]: 78.95-85.19°), mean angulation between LSCA/LCCA was -5.7° (95% CI: -0.9 to 18.7°) and -1.8° (95% CI: 5.4-26.4°) between LCCA/IA. Mean distance between the LSCA and the LCCA was 14.3 mm (95% CI: 13-15.6 mm) and 21.8 mm (95% CI: 20.3-23.4 mm) between LCCA and IA. All diameters of the AA increased with age (P Men had diameters statistically (P women except at the LCCA ostium level. A statistically significant increase of the distances between the LSCA and the LCCA, between the LSCA and the IA and between the IA and the LCCA was found with age, P = 0.027, better understanding of the three-dimensional aspects of the AA, confirmed the variability and heterogeneity of the SAT disposition, and discussed the principles of vascular

  6. Arching Structures in Granular Sedimentary Deposits

    Czech Academy of Sciences Publication Activity Database

    Kulaviak, Lukáš; Hladil, Jindřich; Růžička, Marek; Drahoš, Jiří; Saint-Lary, L.

    2013-01-01

    Roč. 246, SEP (2013), s. 269-277 ISSN 0032-5910 R&D Projects: GA ČR GA104/07/1110; GA AV ČR IAAX00130702; GA MŠk(CZ) LG11014 Institutional support: RVO:67985858 ; RVO:67985831 Keywords : wet granulars * deposit * arching structure Subject RIV: CI - Industrial Chemistry, Chemical Engineering; DB - Geology ; Mineralogy (GLU-S) Impact factor: 2.269, year: 2013

  7. Maximum support resistance with steel arch backfilling

    Energy Technology Data Exchange (ETDEWEB)

    1983-01-01

    A system of backfilling for roadway arch supports to replace timber and debris lagging is described. Produced in West Germany, it is known as the Bullflex system and consists of 23 cm diameter woven textile tubing which is inflated with a pumpable hydraulically-setting filler of the type normally used in mines. The tube is placed between the back of the support units and the rock face and creates an early-stage interlocking effect.

  8. Complete-arch accuracy of intraoral scanners.

    Science.gov (United States)

    Treesh, Joshua C; Liacouras, Peter C; Taft, Robert M; Brooks, Daniel I; Raiciulescu, Sorana; Ellert, Daniel O; Grant, Gerald T; Ye, Ling

    2018-04-30

    Intraoral scanners have shown varied results in complete-arch applications. The purpose of this in vitro study was to evaluate the complete-arch accuracy of 4 intraoral scanners based on trueness and precision measurements compared with a known reference (trueness) and with each other (precision). Four intraoral scanners were evaluated: CEREC Bluecam, CEREC Omnicam, TRIOS Color, and Carestream CS 3500. A complete-arch reference cast was created and printed using a 3-dimensional dental cast printer with photopolymer resin. The reference cast was digitized using a laboratory-based white light 3-dimensional scanner. The printed reference cast was scanned 10 times with each intraoral scanner. The digital standard tessellation language (STL) files from each scanner were then registered to the reference file and compared with differences in trueness and precision using a 3-dimensional modeling software. Additionally, scanning time was recorded for each scan performed. The Wilcoxon signed rank, Kruskal-Wallis, and Dunn tests were used to detect differences for trueness, precision, and scanning time (α=.05). Carestream CS 3500 had the lowest overall trueness and precision compared with Bluecam and TRIOS Color. The fourth scanner, Omnicam, had intermediate trueness and precision. All of the scanners tended to underestimate the size of the reference file, with exception of the Carestream CS 3500, which was more variable. Based on visual inspection of the color rendering of signed differences, the greatest amount of error tended to be in the posterior aspects of the arch, with local errors exceeding 100 μm for all scans. The single capture scanner Carestream CS 3500 had the overall longest scan times and was significantly slower than the continuous capture scanners TRIOS Color and Omnicam. Significant differences in both trueness and precision were found among the scanners. Scan times of the continuous capture scanners were faster than the single capture scanners

  9. Proceedings of the Canadian Dam Association's 2006 annual conference: dams: past, present and future

    International Nuclear Information System (INIS)

    2006-01-01

    This conference addressed particular technical challenges regarding the operation of dams with particular focus on best practices for improving dam management and safety. It featured 4 workshops and a technical program led by experts on dams and tailings facilities that addressed topics such as dam construction, design and rehabilitation; dam management in a hydrological uncertainty context; monitoring, instrumentation and maintenance; dam behaviour; dam safety, dam failure and practical approaches to emergency preparedness planning for dam owners; historical aspects and environmental issues and conflicting water use. Recent developments in dam construction were reviewed along with discharge and debris management, tailings dam issues, asset management, seismic issues, public safety, seepage monitoring, flow control, dam rehabilitation, concrete testing, hydrotechnical issues, risk assessment methodology, and dam safety guidelines for extreme flood analyses and their applications. All 80 presentations from this conference have been catalogued separately for inclusion in this database. refs., tabs., figs

  10. Hybrid treatment of aortic arch disease

    Science.gov (United States)

    Metzger, Patrick Bastos; Rossi, Fabio Henrique; Moreira, Samuel Martins; Issa, Mario; Izukawa, Nilo Mitsuru; Dinkhuysen, Jarbas J.; Spina Neto, Domingos; Kambara, Antônio Massamitsu

    2014-01-01

    Introduction The management of thoracic aortic disease involving the ascending aorta, aortic arch and descending thoracic aorta are technically challenging and is an area in constant development and innovation. Objective To analyze early and midterm results of hybrid treatment of arch aortic disease. Methods Retrospective study of procedures performed from January 2010 to December 2012. The end points were the technical success, therapeutic success, morbidity and mortality, neurologic outcomes, the rate of endoleaks and reinterventions. Results A total of 95 patients treated for thoracic aortic diseases in this period, 18 underwent hybrid treatment and entered in this study. The average ages were 62.3 years. The male was present in 66.7%. The technical and therapeutic success was 94.5% e 83.3%. The perioperative mortality rate of 11.1%. There is any death during one-year follow- up. The reoperation rates were 16.6% due 2 cases of endoleak Ia and one case of endoleak II. There is any occlusion of anatomic or extra anatomic bypass during follow up. Conclusion In our study, the hybrid treatment of aortic arch disease proved to be a feasible alternative of conventional surgery. The therapeutic success rates and re- interventions obtained demonstrate the necessity of thorough clinical follow-up of these patients in a long time. PMID:25714205

  11. 7 CFR 1724.55 - Dam safety.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 11 2010-01-01 2010-01-01 false Dam safety. 1724.55 Section 1724.55 Agriculture... § 1724.55 Dam safety. (a) The provisions of this section apply only to RUS financed electric system... for Dam Safety,”(Guidelines), as applicable. A dam, as more fully defined in the Guidelines, is...

  12. Initial arch wires for tooth alignment during orthodontic treatment with fixed appliances.

    Science.gov (United States)

    Jian, Fan; Lai, Wenli; Furness, Susan; McIntyre, Grant T; Millett, Declan T; Hickman, Joy; Wang, Yan

    2013-04-30

    Initial arch wires are the first arch wires to be inserted into the fixed appliance at the beginning of orthodontic treatment and are used mainly for the alignment of teeth by correcting crowding and rotations. With a number of different types 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. This is an update of the review 'Initial arch wires for alignment of crooked teeth with fixed orthodontic braces' first published in the Cochrane Database of Systematic Reviews 2010, Issue 4. To assess the effects of initial arch wires for alignment of teeth with fixed orthodontic braces in relation to alignment speed, root resorption and pain intensity. We searched the following electronic databases: the Cochrane Oral Health Group's Trials Register (to 2 August 2012), CENTRAL (The Cochrane Library 2012, Issue 7), MEDLINE via OVID (1950 to 2 August 2012) and EMBASE via OVID (1980 to 2 August 2012). We also searched the reference lists of relevant articles. There was no restriction with regard to publication status or language of publication. We contacted all authors of included studies to identify additional studies. We included randomised controlled trials (RCTs) of initial arch wires to align teeth with fixed orthodontic braces. Only studies involving participants with upper and/or lower full arch fixed orthodontic appliances were included. Two review authors were responsible for study selection, validity assessment and data extraction. All disagreements were resolved by discussion amongst the review team. Corresponding authors of included studies were contacted to obtain missing information. Nine RCTs with 571 participants were included in this review. All trials were at high risk of bias and a number of methodological limitations were identified. All trials had at least one

  13. Perspectives on dam safety in Canada

    International Nuclear Information System (INIS)

    Halliday, R.

    2004-01-01

    Canadian dam safety issues were reviewed from the perspective of a water resources engineer who is not a dam safety practitioner. Several external factors affecting dam safety were identified along with perceived problems in dam safety administration. The author claims that the main weakness in safety practices can be attributed to provincial oversights and lack of federal engagement. Some additions to the Canadian Dam Safety Guidelines were proposed to address these weaknesses. Canada has hundreds of large dams and high hazard dams whose failure would result in severe downstream consequences. The safety of dams built on boundary waters shared with the United States have gained particular attention from the International Joint Commission. This paper also examined safety criteria for concerns such as aging dams, sabotage and global climate change that may compromise the safety of a dam. 26 refs

  14. Calculating earth dam seepage using HYDRUS software applications

    Directory of Open Access Journals (Sweden)

    Jakub Nieć

    2017-06-01

    Full Text Available This paper presents simulations of water seepage within and under the embankment dam of Lake Kowalskie reservoir. The aim of the study was to compare seepage calculation results obtained using analytical and numerical methods. In April 1985, after the first filling of the reservoir to normal storage levels, water leaks was observed at the base of the escarpment, on the air side of the dam. In order to control seepage flow, drainage was performed and additional piezometers installed. To explain the causes of increased pressure in the aquifer under the dam in May 1985 a simplified calculation of filtration was performed. Now, on the basis of archived data from the Department of Hydraulic and Sanitary Engineering using 3D HYDRUS STANDARD software, the conditions of seepage under the dam have been recreated and re-calculated. Piezometric pressure was investigated in three variants of drainage, including drainage before and after modernization.

  15. 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.

  16. Ririe Dam Release Test Assessment

    Science.gov (United States)

    2013-06-01

    Notes HEC - RAS Location Station (ft) Observation Notes 1420 Ririe Dam Ririe Dam 119,880 Gates opened and initial release started. 1455 115th St...16°F air temperature. Table A2. Observations made on 11 February 2013. Time Location Notes HEC - RAS Location Station (ft) Observation Notes...ERDC/CRREL TR-13-10 52 Time Location Notes HEC - RAS Location Station (ft) Observation Notes Travel Time* (sec) Vel.** (fps) 1224 5th

  17. Feasibility of groundwater recharge dam projects in arid environments

    Science.gov (United States)

    Jaafar, H. H.

    2014-05-01

    A new method for determining feasibility and prioritizing investments for agricultural and domestic recharge dams in arid regions is developed and presented. The method is based on identifying the factors affecting the decision making process and evaluating these factors, followed by determining the indices in a GIS-aided environment. Evaluated parameters include results from field surveys and site visits, land cover and soils data, precipitation data, runoff data and modeling, number of beneficiaries, domestic irrigation demand, reservoir objectives, demography, reservoirs yield and reliability, dam structures, construction costs, and operation and maintenance costs. Results of a case study on more than eighty proposed dams indicate that assessment of reliability, annualized cost/demand satisfied and yield is crucial prior to investment decision making in arid areas. Irrigation demand is the major influencing parameter on yield and reliability of recharge dams, even when only 3 months of the demand were included. Reliability of the proposed reservoirs as related to their standardized size and net inflow was found to increase with increasing yield. High priority dams were less than 4% of the total, and less priority dams amounted to 23%, with the remaining found to be not feasible. The results of this methodology and its application has proved effective in guiding stakeholders for defining most favorable sites for preliminary and detailed design studies and commissioning.

  18. Climate change and the causes of dam failures in Australia

    International Nuclear Information System (INIS)

    Lewis, B.

    2007-01-01

    As a result of poor dam construction methods in Australia and significant droughts occurring over the past 60 years, there is a danger that mistakes made during previous droughts will be repeated. Dams were often built in soils of very low moisture content to ensure a properly compacted bank. As a result of these poor construction methods, the drought years have produced an unusually high number of dam failures. This paper discussed the causes of dam failures such as dispersive clays and defects in associated structures. The discussion on dispersive clays included cracking, piping, tunneling, and slides. Dispersive clays occur in soils whose clay minerals separate into single grains when placed in contact with water and are associated with high soil erodability and their distribution often coincides with the occurrence of erosion gullying, rilling and piping. Dispersive clays in a dam embankment can result in the leaching out of material from the embankment with consequent erosion and failure. Defects in associated structures that were discussed included spillway blockage and outlet pipe blockage. It was concluded that dam failures are seldom due to one particular cause but rather due to one weakness triggering another. It was concluded that failures are difficult and expensive to remedy. 9 refs., 4 figs

  19. Coexistence of Single Coronary Artery Anomaly and Aortic Arch Anomaly

    Directory of Open Access Journals (Sweden)

    Yilmaz Omur Otlu

    2014-03-01

    Full Text Available A 74-year-old male patient was admitted to our hospital for evaluation of recent onset atypical chest pain. His medical history included hypertension, dislipidemia and smoking. Physical examination was unremarkable. The resting electrocardiogram was demonstrated biphasic T waves on lateral derivations. Transthoracic echocardiography showed normal left and right ventricular dimensions and functions. Coronary angiography was planned for the patient. First, right transradial approach tried; but guidewire could not be advanced to ascendig aorta. Coronary angiography was performed through the right femoral artery. Multiple attempts to cannulate the left coronary ostium were unsuccessful. The right coronary artery cannulated from its normal ostium in the right sinus of Valsalva. After a very short common main stem, the artery divided into a right coronary artery, and separate left anterior descending artery and circumflex artery (Figure A. The coronary arteries were normal without any significant stenosis and any extrinsic compression. An aortic root injection confirmed the absence of left coronary ostium. Also, a retroesophageal right subclavian artery originating from the left aortic arch (arteria lusoria was detected as the last branch of aortic arch on contrast enhanced computerized tomography (Figure B-C. The patient discharged with medical teraphy.

  20. Differences in the Microbial Colonization Among Arch Wire Types, Gauges and Cross Sections

    Directory of Open Access Journals (Sweden)

    Reem A. Rafeeq

    2018-02-01

    Full Text Available Background: The presence of orthodontic materials in the oral cavity represent a unique surface that can interact with bacteria, leading to pathogenic plaque formation and subsequent enamel demineralization, Streptococcus mutans play an important role in the initiation and progression of dental caries and they are considered the primary cause of bacteriological caries. The objective of this study was to investigate the effect of multiple factors including the type of arch wire, salivary coating, cross section, and wire thickness on the levels of mutans streptococci adherence. Materials and Methods: Two types of arch wire stainless steel and nickel titanium were selected using the following criteria: round and rectangular with gauges 0.014, 0.018, 0.016 × 0.022 and 0.019 × 0.0 25 inches which were subdivided into eight groups. Bacterial adhesion was quantified by a microbial culture technique and the number of adhesive bacteria were analyzed and counted after growth in culture for each group with and without saliva coating at 15 and 60 minutes. Detection of mutans streptococci by saliva-check Mutans test. Results: There was a significant difference between arch wire types in each time interval and the highest bacterial adhesion on the NiTi arch wires with rectangular cross section in the absence of saliva with extended incubation time. Conclusions: The adherence of mutans streptococci in saliva coated wires seems to be low. At increased incubation time, rectangular cross section arch wire showed an increased number of adhering bacteria with less effect on different gauges of the arch wire.

  1. First Branchial Arch Fistula: A Rarity and a Surgical Challenge.

    Science.gov (United States)

    Rajkumar, J S; Ganesh, Deepa; Anirudh, J R; Akbar, S; Joshi, Niraj

    2016-06-01

    Although 2(nd) Branchial arch fistulae (from incomplete closure of Cervical sinus of His) are well known, 1(st) arch fistulae are much rarer (branchial arch fistula of the type II Arnot classification, which presented with two external openings of more than 20 years duration. Patient had a successful resection of all the concerned fistulous tract. Review of literature and the surgical challenges of the procedure are presented herewith.

  2. Evaluation of behaviors of earth and rockfill dams during construction and initial impounding using instrumentation data and numerical modeling

    Directory of Open Access Journals (Sweden)

    Mohammad Rashidi

    2017-08-01

    Full Text Available In this study, the behavior of Gavoshan dam was evaluated during construction and the first impounding. A two-dimensional (2D numerical analysis was conducted based on a finite difference method on the largest cross-section of the dam using the results of instrument measurements and back analysis. These evaluations will be completed in the case that back analysis is carried out in order to control the degree of the accuracy and the level of confidence of the measured behavior since each of the measurements could be controlled by comparing it to the result obtained from the numerical model. Following that, by comparing the results of the numerical analysis with the measured values, it is indicated that there is a proper consistency between these two values. Moreover, it was observed that the dam performance was suitable regarding the induced pore water pressure, the pore water pressure ratio ru, settlement, induced stresses, arching degree, and hydraulic fracturing probability during the construction and initial impounding periods. The results demonstrated that the maximum settlement of the core was 238 cm at the end of construction. In the following 6 years after construction (initial impounding and exploitation period, the accumulative settlement of the dam was 270 cm. It is clear that 88% of the total settlement of the dam took place during dam construction. The reason is that the clay core was smashed in the wet side, i.e. the optimum moisture content. Whereas the average curving ratio was 0.64 during dam construction; at the end of the initial impounding, the maximum amount of curving ratio in the upstream was 0.81, and the minimum (critical amount in the downstream was 0.52. It was also concluded that this dam is safe in comparison with the behaviors of other similar dams in the world.

  3. The Social, Historical, and Institutional Contingencies of Dam Removal

    Science.gov (United States)

    Magilligan, F. J.; Sneddon, C. S.; Fox, C. A.

    2017-06-01

    Environmental managers in the United States and elsewhere are increasingly perceiving dam removal as a critical tool for river restoration and enhancing watershed resilience. In New England, over 125 dams have been dismantled for ecological and economic rationales. A surprising number of these removals, including many that are ongoing, have generated heated conflicts between restoration proponents and local communities who value their dammed landscapes. Using a comparative case study approach, we examine the environmental conflict around efforts to remove six dams in New England. Each of these removal efforts followed quite different paths and resultant outcomes: successful removal, stalled removal, and failure despite seemingly favorable institutional conditions. Lengthy conflicts often transpired in instances where removals occurred, but these were successfully arbitrated by paying attention to local historical-geographical conditions conducive to removal and by brokering effective compromises between dam owners and the various local actors and stakeholders involved in the removal process. Yet our results across all cases suggest that these are necessary, but not sufficient conditions for restoration through dam removal since a similar set of conditions typified cases where removals are continuously stalled or completely halted. Scholars examining the intersection between ecological restoration and environmental politics should remain vigilant in seeking patterns and generalities across cases of environmental conflict in order to promote important biophysical goals, but must also remain open to the ways in which those goals are thwarted and shaped by conflicts that are deeply contingent on historical-geographical conditions and broader institutional networks of power and influence.

  4. The Social, Historical, and Institutional Contingencies of Dam Removal.

    Science.gov (United States)

    Magilligan, F J; Sneddon, C S; Fox, C A

    2017-06-01

    Environmental managers in the United States and elsewhere are increasingly perceiving dam removal as a critical tool for river restoration and enhancing watershed resilience. In New England, over 125 dams have been dismantled for ecological and economic rationales. A surprising number of these removals, including many that are ongoing, have generated heated conflicts between restoration proponents and local communities who value their dammed landscapes. Using a comparative case study approach, we examine the environmental conflict around efforts to remove six dams in New England. Each of these removal efforts followed quite different paths and resultant outcomes: successful removal, stalled removal, and failure despite seemingly favorable institutional conditions. Lengthy conflicts often transpired in instances where removals occurred, but these were successfully arbitrated by paying attention to local historical-geographical conditions conducive to removal and by brokering effective compromises between dam owners and the various local actors and stakeholders involved in the removal process. Yet our results across all cases suggest that these are necessary, but not sufficient conditions for restoration through dam removal since a similar set of conditions typified cases where removals are continuously stalled or completely halted. Scholars examining the intersection between ecological restoration and environmental politics should remain vigilant in seeking patterns and generalities across cases of environmental conflict in order to promote important biophysical goals, but must also remain open to the ways in which those goals are thwarted and shaped by conflicts that are deeply contingent on historical-geographical conditions and broader institutional networks of power and influence.

  5. Special design issues related to the G. Ross Lord Dam constructed in Metropolitan Toronto

    Energy Technology Data Exchange (ETDEWEB)

    Sowa, V.A. [Jacques Whitford and Associates Ltd., Vancouver, BC (Canada); Tawil, A.H. [Acres International Ltd., Niagara Falls, ON (Canada); Haley, D.R. [Toronto Region and Conservation Authority, Downsview, ON (Canada)

    2002-07-01

    This paper describes the special considerations required to build a flood control dam in a metropolitan area that holds major city infrastructures such as power transmission towers, pipelines, sanitary sewers and graveyards. The paper refers to the G. Ross Lord Dam, a 20 m high earth fill flood control dam which was constructed in 1973 on the West Branch of the Don River in Toronto. It was built following recommendations after Hurricane Hazel caused widespread flooding and the death of 81 people in 1954. The dam includes a concrete chute spillway and stilling basin. The geotechnical design of the dam was described along with the dam structures and the methods used to flood proof the infrastructure. The dam has a sloping impervious core and an upstream blanket to reduce seepage. Seepage control is provided by a drainage blanket and a chimney drain. A main overflow spillway was constructed on the south abutment, and a low level outlet was constructed at the base of the dam to accommodate normal river flows through the dam. Most of the water level control during a flood event is provided by the main overflow spillway. Spillway slab anchor keys prevent down slope creep of the slabs. The dam, the spillway and the reservoir structure have performed well since construction. 6 refs., 10 figs.

  6. [Extension of (extremely) shortened dental arches by fixed or removable partial dentures

    NARCIS (Netherlands)

    Witter, D.J.; Hoefnagel, R.A.; Snoek, P.A.; Creugers, N.H.J.

    2009-01-01

    Whether a shortened dental arch needs to be extended depends on the degree of the shortening. Four categories of shortened dental arches can be distinguished: 1. slightly shortened dental arches; 2. moderately shortened dental arches; 3. extremely shortened dental arches; and 4. asymmetrical

  7. Monitoring of arched sched ground layer

    International Nuclear Information System (INIS)

    Listjak, M.; Slaninka, A.; Rau, L.; Pajersky, P.

    2015-01-01

    Arched Shed was a part of controlled area of NPP A1 site in Jaslovske Bohunice (Slovakia). It had been used for temporary storage of loose radioactive waste (RAW) which has been characterized within the BIDSF project C13, Characterisation of Loose Radioactive Waste'. Stored RAW has been treated and sorted within the project ',Realization of the 2 nd stage of Decommissioning Project of NPP A1'. Area of Arched Shed represents approximately 270 m 2 (45 m x 6 m). Ground layer of the AS consists mostly of soil with solid elements (stones and gravel). The aim of monitoring was to remove the contaminated soil up to 1 m below ground level. Requirement for detail monitoring of the Arched Shed ground layer resulted from conclusions of the BIDSF project C13 which has proved that massic activity 137 Cs of soil was up to few thousands Bq·kg -1 in underground layer. Dominant easy to measure radionuclide in the soil is 137 Cs which has been used as a key radionuclide for methodology of in-situ soil monitoring. Following methods has been applied during characterization: dose rate survey, sampling from defined ground layer followed by laboratory gamma spectrometry analysis by the accredited testing laboratory of radiation dosimetry VUJE (S-219) and in-situ scintillation gamma spectrometry by 1.5''x1.5'' LaBr detector. Massic activity of the remaining soil (not excavated) comply the criteria for free release into the environment (Government Regulation of Slovak Republic 345/2006 Coll.). Area was filled up by non-contaminated soil up to the ground level of surroundings. Afterward the area was covered with geotextile and concrete panels and nowadays it is ready for further usage within the NPP A1 decommissioning project as a place for treatment, conditioning and disposal of contaminated soil and concrete. (authors)

  8. Bovine aortic arch with supravalvular aortic stenosis.

    Science.gov (United States)

    Idhrees, Mohammed; Cherian, Vijay Thomas; Menon, Sabarinath; Mathew, Thomas; Dharan, Baiju S; Jayakumar, K

    2016-09-01

    A 5-year-old boy was diagnosed to have supravalvular aortic stenosis (SVAS). On evaluation of CT angiogram, there was associated bovine aortic arch (BAA). Association of BAA with SVAS has not been previously reported in literature, and to best of our knowledge, this is the first case report of SVAS with BAA. Recent studies show BAA as a marker for aortopathy. SVAS is also an arteriopathy. In light of this, SVAS can also possibly be a manifestation of aortopathy associated with BAA. Copyright © 2015 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.

  9. Bovine aortic arch with supravalvular aortic stenosis

    Directory of Open Access Journals (Sweden)

    Mohammed Idhrees

    2016-09-01

    Full Text Available A 5-year-old boy was diagnosed to have supravalvular aortic stenosis (SVAS. On evaluation of CT angiogram, there was associated bovine aortic arch (BAA. Association of BAA with SVAS has not been previously reported in literature, and to best of our knowledge, this is the first case report of SVAS with BAA. Recent studies show BAA as a marker for aortopathy. SVAS is also an arteriopathy. In light of this, SVAS can also possibly be a manifestation of aortopathy associated with BAA.

  10. [Single coronary artery and right aortic arch].

    Science.gov (United States)

    Martínez-Quintana, Efrén; Rodríguez-González, Fayna

    2015-01-01

    Coronary anomalies are mostly asymptomatic and diagnosed incidentally during coronary angiography or echocardiography. However, they must be taken into account in the differential diagnosis of angina, dyspnea, syncope, acute myocardial infarction or sudden death in young patients. The case is presented of two rare anomalies, single coronary artery originating from right sinus of Valsalva and right aortic arch, in a 65 year-old patient with atherosclerotic coronary artery disease treated percutaneously. Copyright © 2014 Sociedad Española de Arteriosclerosis. Published by Elsevier España. All rights reserved.

  11. 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

  12. Qu'Appelle River Dam, dam break analysis using advanced GIS tools for rapid modelling and inundation mapping

    Energy Technology Data Exchange (ETDEWEB)

    Bonin, D. [Hatch Energy, Winnipeg, MB (Canada); Campbell, C. [Saskatchewan Watershed Authority, Moose Jaw, SK (Canada); Groeneveld, J. [Hatch Energy, Calgary, AB (Canada)

    2008-07-01

    The South Saskatchewan River Project (SSRP) comprises a multi-purpose reservoir that provides water for conservation and irrigation, flood control, power generation, recreation, and municipal and industrial water supply. In addition to the 64 m high Gardiner Dam, the 27 m high Qu'Appelle River Dam and the 22 km long Lake Diefenbaker Reservoir, the SSRP also includes ancillary works. The Qu'Appelle River valley extends for 458 km before connecting to the Assiniboine River. The valley is incised up to 90 m in depth and is a popular cottaging and recreational area with several major communities located in the flood plain. In the event of a breach of the Qu'Appelle Dam, the discharge will increase from a normal maximum discharge of under 60 m{sup 3} per second to over 50,000 m{sup 3} per second. The Saskatchewan Watershed Authority (SWA) is responsible for ensuring safe development of the Province's water resources, without affecting reservoir or lake operations, and preventing damage from flooding, erosion or land slides. It is in the process of developing Hazard Assessments and emergency preparedness plans for each of their dams in accordance with the Canadian Dam Safety Guidelines. Studies using GIS technology and the hydrodynamic routing model HEC-RAS have been completed to evaluate the potential inundation that may result in the event of failure of the Qu'Appelle River Dam. These studies involved the development of a breach parameter model using a breach data set revised to better reflect the Qu'Appelle River Dam; the development of a dam break model for the Qu'Appelle River Dam and downstream river and flood plain; and, the use of this model to simulate two potential dam failure scenarios for the Qu'Appelle River Dam, notably failure during passage of the PMF and failure during fair weather conditions. Inundation maps have been prepared for the downstream Qu'Appelle River valley for each of the above events. 3 refs., 4

  13. Role of Dlx6 in regulation of an endothelin-1-dependent, dHAND branchial arch enhancer

    Science.gov (United States)

    Charité, Jeroen; McFadden, David G.; Merlo, Giorgio; Levi, Giovanni; Clouthier, David E.; Yanagisawa, Masashi; Richardson, James A.; Olson, Eric N.

    2001-01-01

    Neural crest cells play a key role in craniofacial development. The endothelin family of secreted polypeptides regulates development of several neural crest sublineages, including the branchial arch neural crest. The basic helix–loop–helix transcription factor dHAND is also required for craniofacial development, and in endothelin-1 (ET-1) mutant embryos, dHAND expression in the branchial arches is down-regulated, implicating it as a transcriptional effector of ET-1 action. To determine the mechanism that links ET-1 signaling to dHAND transcription, we analyzed the dHAND gene for cis-regulatory elements that control transcription in the branchial arches. We describe an evolutionarily conserved dHAND enhancer that requires ET-1 signaling for activity. This enhancer contains four homeodomain binding sites that are required for branchial arch expression. By comparing protein binding to these sites in branchial arch extracts from endothelin receptor A (EdnrA) mutant and wild-type mouse embryos, we identified Dlx6, a member of the Distal-less family of homeodomain proteins, as an ET-1-dependent binding factor. Consistent with this conclusion, Dlx6 was down-regulated in branchial arches from EdnrA mutant mice. These results suggest that Dlx6 acts as an intermediary between ET-1 signaling and dHAND transcription during craniofacial morphogenesis. PMID:11711438

  14. Standardizing foot-type classification using arch index values.

    Science.gov (United States)

    Wong, Christopher Kevin; Weil, Rich; de Boer, Emily

    2012-01-01

    The lack of a reliable classification standard for foot type makes drawing conclusions from existing research and clinical decisions difficult, since different foot types may move and respond to treatment differently. The purpose of this study was to determine interrater agreement for foot-type classification based on photo-box-derived arch index values. For this correlational study with two raters, a sample of 11 healthy volunteers with normal to obese body mass indices was recruited from both a community weight-loss programme and a programme in physical therapy. Arch index was calculated using AutoCAD software from footprint photographs obtained via mirrored photo-box. Classification as high-arched, normal, or low-arched foot type was based on arch index values. Reliability of the arch index was determined with intra-class correlations; agreement on foot-type classification was determined using quadratic weighted kappa (κw). Average arch index was 0.215 for one tester and 0.219 for the second tester, with an overall range of 0.017 to 0.370. Both testers classified 6 feet as low-arched, 9 feet as normal, and 7 feet as high-arched. Interrater reliability for the arch index was ICC=0.90; interrater agreement for foot-type classification was κw=0.923. Classification of foot type based on arch index values derived from plantar footprint photographs obtained via mirrored photo-box showed excellent reliability in people with varying BMI. Foot-type classification may help clinicians and researchers subdivide sample populations to better differentiate mobility, gait, or treatment effects among foot types.

  15. Standardizing Foot-Type Classification Using Arch Index Values

    Science.gov (United States)

    Weil, Rich; de Boer, Emily

    2012-01-01

    ABSTRACT Purpose: The lack of a reliable classification standard for foot type makes drawing conclusions from existing research and clinical decisions difficult, since different foot types may move and respond to treatment differently. The purpose of this study was to determine interrater agreement for foot-type classification based on photo-box-derived arch index values. Method: For this correlational study with two raters, a sample of 11 healthy volunteers with normal to obese body mass indices was recruited from both a community weight-loss programme and a programme in physical therapy. Arch index was calculated using AutoCAD software from footprint photographs obtained via mirrored photo-box. Classification as high-arched, normal, or low-arched foot type was based on arch index values. Reliability of the arch index was determined with intra-class correlations; agreement on foot-type classification was determined using quadratic weighted kappa (κw). Results: Average arch index was 0.215 for one tester and 0.219 for the second tester, with an overall range of 0.017 to 0.370. Both testers classified 6 feet as low-arched, 9 feet as normal, and 7 feet as high-arched. Interrater reliability for the arch index was ICC=0.90; interrater agreement for foot-type classification was κw=0.923. Conclusions: Classification of foot type based on arch index values derived from plantar footprint photographs obtained via mirrored photo-box showed excellent reliability in people with varying BMI. Foot-type classification may help clinicians and researchers subdivide sample populations to better differentiate mobility, gait, or treatment effects among foot types. PMID:23729964

  16. Review Article: Numerical analysis of the seismic behaviour of earth dam

    Directory of Open Access Journals (Sweden)

    Y. Parish

    2009-03-01

    Full Text Available The present study concerns analysis of the seismic response of earth dams. The behaviour of both the shell and core of the dam is described using the simple and popular non associated Mohr-Coulomb criterion. The use of this constitutive model is justified by the difficulty to obtain constitutive parameters for more advanced constitutive relations including isotropic and kinematic hardening. Analyses with real earthquake records show that the seismic loading induces plasticity in a large part of the shell and in the lower part of the core. Analysis shows that plasticity should be considered in the analysis of the seismic response of the dam, because it leads to a decrease in the natural frequencies of the dam together to energy dissipation, which could significantly affect the seismic response of the dam. Plastic analysis constitutes also a good tool for the verification of the stability of the dam under seismic loading.

  17. Arch therapy clinical case of electrons

    International Nuclear Information System (INIS)

    Larrinaga Cortina, Eduardo Francisco; Rodriguez Velorio, Ceferina; Alonso Samper, Jose Luis

    2009-01-01

    From 1998 to 2006, the Ministry of Public Health of the Republic of Cuba maintained a balanced collaboration with the Social Security Fund (CCSS) of the Republic of Costa Rica with the objective of providing professional services in radiotherapy. As part of the Cuban mission in the 2003-2005 period was conducted clinic design and implementation of a dynamic rotational technique with electron beams for treatment of a neoplastic lesion from the neuro ectoderm early in the first linear accelerator belonging to the CCSS and installed in Hospital Mexico, San Jose. The objective was to achieve locoregional control of the lesion by treatment Radiant surgical bed in the chest wall. We discuss different options settings for the treatment values arch therapy the best choice taking into account the cylindrical geometry of the treatment area and the superficiality of its location. For the determination of the absolute dose used Khan's recommendations. Treatment planning was done following the methodology suggested by Podgorsak et al. We performed a quality control of patient-specific planning and dosimetry in anthropomorphic dummy radiographic, resulting in isodose distribution of very good uniformity in the area of clinical interest. The electron arch therapy technique proved to be superior to alternative proposals for the treatment of superficial lesions with cylindrical symmetry frankly, with regard to dose homogeneity in the target volume and lower dose in critical organs. (author)

  18. [Right lung cancer with right aortic arch].

    Science.gov (United States)

    Kawaguchi, Yasuo; Noriyuki, T; Kuroda, Y; Kuranishi, F; Nakahara, M; Fukuda, T; Ishizaki, Y; Hotta, R; Akimoto, E; Mori, H

    2008-02-01

    An abnormal shadow was detected on chest X-ray mass screening in an asymptomatic 63-year-old man. The further examinations revealed the shadow to be primary lung cancer (Rt. S6. adenocarcinoma, cT2N0M0, c-stage IB) with right aortic arch. We used 3 dimentional-computed tomography (3D-CT) to assess an anatomical feature of vessels in detail. The right lower lobectomy and the dissection of medi astinal lymph nodes was performed. We confirmed no abnormal anatomy of pulmonary artery and vein at surgery, and it was possible to perform right lower lobectomy with the common procedure. Since lymph node was found by intraopetrative pathological examination, since no metastasis from interlobar to subcarinal lymph node was found, we did not perform dissection of upper mediastinal dissection, which was equivalent to ND2a lymph nodes dissection of the left lung cancer in General Rule for Clinical and Pathological Record of Lung Cancer. The patient with right aortic arch is known to have variant anatomy of other intrathoracic vessels occasionally. 3D-CT was quite useful in assessing anatomical feature, and enabled us to perform safe operation.

  19. Perspectives on the Salience and Magnitude of Dam Impacts for Hydro Development Scenarios in China

    Directory of Open Access Journals (Sweden)

    Desiree Tullos

    2010-06-01

    Survey results indicate differences in the perceived salience and magnitude of impacts across both expert groups and dam scenarios. Furthermore, surveys indicate that stakeholder perceptions changed as the information provided regarding dam impacts became more specific, suggesting that stakeholder evaluation may be influenced by quality of information. Finally, qualitative comments from the survey reflect some of the challenges of interdisciplinary dam assessment, including cross-disciplinary cooperation, data standardisation and weighting, and the distribution and potential mitigation of impacts. Given the complexity of data and perceptions around dam impacts, decision-support tools that integrate the objective magnitude and perceived salience of impacts are required urgently.

  20. River Restoration by Dam Removal: Assessing Riverine Re-Connectivity Across New England

    Science.gov (United States)

    Magilligan, F. J.; Nislow, K. H.; Graber, B.; Sneddon, C.; Fox, C.; Martin, E.

    2014-12-01

    The impacts of dams in New England are especially acute as it possesses one of the highest densities of dams in the US, with the NID documenting more than 4,000 dams, and state agency records indicating that >14,000 dams are peppered throughout the landscape. This large number of dams contributes to pervasive watershed fragmentation, threatening the ecological integrity of rivers and streams, and in the case of old, poorly maintained structures, posing a risk to lives and property. These concerns have generated active dam removal efforts throughout New England. To best capture the geomorphic, hydrologic, and potential ecological effects of dam removal at a regional level, we have compiled a dataset of 127 removed dams in New England, which includes information about structural characteristics, georectified locations, and key watershed attributes (including basin size, distance to next upstream obstacle, and number of free-flowing river kms opened up). Our specific research questions address (1) what is the spatial distribution of removed dams and how does this pattern relate to stated management goals of restoring critical habitat for native resident freshwater and diadromous fish, (2) what are the structural or management commonalities in dam types that have been removed, and (3) what has been the incremental addition of free-flowing river length? Rather than reflecting an overall management prioritization strategy, results indicate that dam removals are characterized more by opportunistic removals. For example, despite a regional emphasis on diadromous fish protection and restoration, most removals are inland rather than coastal settings. Most of the removed dams were small (~ 45% 2,300 river kms over the past several decades, with implication for both resident and diadromous fish, and with many removals located in mid-sized rivers that are a key link between upstream and downstream/coastal aquatic ecosystems.

  1. Watershed restoration: planning and implementing small dam removals to maximize ecosystem services

    Science.gov (United States)

    Tonitto, C.; Riha, S. J.

    2016-12-01

    River restoration and enhancing watershed connectivity is of growing concern in industrialized nations. The past two decades have seen a number of small dam removals, though many removals remain unstudied and poorly documented. We summarize socio-economic and biophysical lessons learned during the past two decades of accelerated activity regarding small dam removals throughout the United States. We present frameworks for planning and implementing removals developed by interdisciplinary engagement. Toward the goal of achieving thorough dam removal planning, we present outcomes from well-documented small dam removals covering ecological, chemical, and physical change in rivers post-dam removal, including field observation and modeling methodologies. Guiding principles of a dam removal process should include: 1) stakeholder engagement to navigate the complexity of watershed landuse, 2) an impacts assessment to inform the planning process, 3) pre- and post-dam removal observations of ecological, chemical and physical properties, 4) the expectation that there are short- and long-term ecological dynamics with population recovery depending on whether dam impacts were largely related to dispersion or to habitat destruction, 5) an expectation that changes in watershed chemistry are dependent on sediment type, sediment transport and watershed landuse, and 6) rigorous assessment of physical changes resulting from dam removal, understanding that alteration in hydrologic flows, sediment transport, and channel evolution will shape ecological and chemical dynamics, and shape how stakeholders engage with the watershed.

  2. Lateral testing of glued laminated timber tudor arch

    Science.gov (United States)

    Douglas R. Rammer; Philip Line

    2016-01-01

    Glued laminated timber Tudor arches have been in wide use in the United States since the 1930s, but detailed knowledge related to seismic design in modern U.S. building codes is lacking. FEMA P-695 (P-695) is a methodology to determine seismic performance factors for a seismic force resisting system. A limited P-695 study for glued laminated timber arch structures...

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

    DEFF Research Database (Denmark)

    Kristensen, Dennis; Rahbek, Anders Christian

    2009-01-01

    -ARCH -- are derived. Strong consistency is established under the assumptions that the ARCH process is geometrically ergodic, the conditional variance function has a finite log-moment, and finite second moment of the rescaled error. Asymptotic normality of the estimator is established under the additional assumption...

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

    Directory of Open Access Journals (Sweden)

    Jacob Karp

    2012-01-01

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

  5. Examining the economic impacts of hydropower dams on property values using GIS.

    Science.gov (United States)

    Bohlen, Curtis; Lewis, Lynne Y

    2009-07-01

    While the era of dam building is largely over in the United States, globally dams are still being proposed and constructed. The articles in this special issue consider many aspects and impacts of dams around the world. This paper examines dam removal and the measurement of the impacts of dams on local community property values. Valuable lessons may be found. In the United States, hundreds of small hydropower dams will come up for relicensing in the coming decade. Whether or not the licenses are renewed and what happens to the dams if the licenses expires is a subject of great debate. Dams are beginning to be removed for river restoration and fisheries restoration and these "end-of-life" decisions may offer lessons for countries proposing or currently building small (and large) hydropower dams. What can these restoration stories tell us? In this paper, we examine the effects of dams along the Penobscot River in Maine (USA) on residential property values. We compare the results to findings from a similar (but ex post dam removal) data set for properties along the Kennebec river in Maine, where the Edwards Dam was removed in 1999. The Penobscot River Restoration Project, an ambitious basin-wide restoration effort, includes plans to remove two dams and decommission a third along the Penobscot River. Dam removal has significant effects on the local environment, and it is reasonable to anticipate that environmental changes will themselves be reflected in changes in property values. Here we examine historical real estate transaction data to examine whether landowners pay a premium or penalty to live near the Penobscot River or near a hydropower generating dam. We find that waterfront landowners on the Penobscot or other water bodies in our study area pay approximately a 16% premium for the privilege of living on the water. Nevertheless, landowners pay LESS to live near the Penobscot River than they do to live further away, contrary to the expectation that bodies of water

  6. 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...

  7. Douglas County Dam Breach Inundation Areas

    Data.gov (United States)

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

  8. Simulation of Breach Outflow for Earthfill Dam

    International Nuclear Information System (INIS)

    Razad, Azwin Zailti Abdul; Muda, Rahsidi Sabri; Sidek, Lariyah Mohd; Azia, Intan Shafilah Abdul; Mansor, Faezah Hanum; Yalit, Ruzaimei

    2013-01-01

    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.

  9. Coexistence of bilateral first and second branchial arch anomalies

    Science.gov (United States)

    Thakur, J S; Shekar, Vidya; Saluja, Manika; Mohindroo, N K

    2013-01-01

    Branchial arch anomalies are one of the most common congenital anomalies that are usually unilateral and bilateral presentation is rare. The simultaneous presence of bilateral second branchial arch anomalies along with bilateral first arch anomalies is extremely rare, with only three such cases reported in the literature. We present two non-syndromic cases of coexisting bilateral first and second arch anomalies. Developmental anomalies of the branchial apparatus account for 17% of all paediatric cervical masses and are the most common type of congenital cervical mass. They usually present in the paediatric age group. About 96–97% of these anomalies are unilateral. Bilateral presentation is seen in 2–3% having a strong familial association. Congenital syndromes also have been associated with first and second branchial arch anomalies. Thorough clinical examination and investigations should be done to rule out these syndromes. PMID:23580675

  10. Is there a prospect for hybrid aortic arch surgery?

    Science.gov (United States)

    Bashir, Mohamad; Harky, Amer; Bilal, Haris

    2018-05-16

    The surge of endovascular repair of aortic aneurysm in current modern aortic surgery practice has been the key for surgical management of elective cases of thoracic aortic aneurysms. This has paved way for the combined hybrid approach to be amongst the armamentarium for the management of aortic arch disease. The pivotal understanding of the aortic arch natural history coupled with device technology advancement allowed surgeons insight into delivery of hybrid surgery with acceptable morbidity and mortality results. This review article provides current insights into hybrid technique of aortic arch aneurysm repair and the evidences behind its applicability to arch surgery. It is aimed to highlight the challenges encountered for this innovative approach and correlate its challenges to those that are met by the conventional open aortic arch repair.

  11. 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.

  12. 78 FR 53494 - Dam Safety Modifications at Cherokee, Fort Loudoun, Tellico, and Watts Bar Dams

    Science.gov (United States)

    2013-08-29

    ... Bar Dams AGENCY: Tennessee Valley Authority. ACTION: Issuance of Record of Decision. SUMMARY: This... the dam safety modifications at Cherokee, Fort Loudoun, Tellico, and Watts Bar Dams. The notice of... Loudoun, Tellico, and Watts Bar Dams was published in the Federal Register on May 31, 2013. This...

  13. Evaluation of dental arch relationship of patients with unilateral cleft lip and palate

    Directory of Open Access Journals (Sweden)

    Anjuman Preet Kaur Dua

    2016-01-01

    Full Text Available Background: Several classifications have previously been described to assess dental arch relationships of cleft patients and therefore the surgical outcome. The most commonly used method for evaluation of surgical outcome is Goslon Yardstick. Another scoring system that can be used is the modified Huddart/Bodenham scoring system. Aim: The objective of this study was to evaluate the dental arch relationships of subjects with repaired unilateral and cleft lip and palate who come at an orthodontic center by means of Goslon and modified Huddart/Bodenham scoring system and to find a correlation between the two systems. Methodology: The study models of 16 patients (9 males, 7 females with an average age of 14.2 years (range 11–23 years were evaluated for arch constriction by four observers which included two orthodontists and two postgraduate students. Results: The analysis of dental arch relationship using Goslon Yardstick revealed that 63% of patients ranked between Goslon 3 and 5. The mean modified Huddart/Bodenham score was −16.13. Conclusion: The study revealed that modified Huddart/Bodenham scoring system provided better interobserver agreement than Goslon Yardstick by untrained observers. There was a good inverse correlation between two scoring systems.

  14. Vascular geometry as a risk factor for non-penetrating traumatic injuries of the aortic arch.

    Directory of Open Access Journals (Sweden)

    Andreas Schicho

    Full Text Available To assess biomechanical factors in aortic arch geometry contributing to the development of non-penetrating aortic arch injury (NAAI in multiply injured patients with an Injury Severity Score (ISS ≥ 16.230 consecutive multiply injured trauma patients with an ISS ≥ 16 admitted to our Level-I trauma center during a consecutive 24-month period were prospectively included of whom 13 presented with NAAI (5.7%. Standardized whole-body CT in a 2x128-detector-row scanner included a head-and-neck CTA. Aortic arch diameters, width, height, angles and thoracic width and height were measured in individuals with NAAI and ISS-, sex-, age-, and trauma mechanism-matched controls.There was no difference between groups regarding sex, age, ISS, and aortic diameters. The aortic arch angle in individuals with NAAI (71.3° ± 14.9° was larger than in healthy control (60.7° ± 8.6°; p*<0.05. In patients with NAAI, the distance between ascendent and descendent aorta was larger (5.2 cm ± 1.9 cm than in control (2.8 ± 0.5 cm; ***p<0.001. The aortic arch is higher above tracheal bifurcation in NAAI (3.6 cm ± 0.6 cm than in matched control (2.4 cm ± 0.3 cm; ***p<0.001. Accordingly, the area under the aortic arch, calculated as half of an eliptic shape, is significantly larger in patients with NAAI (15.0 cm2 ± 6.5 cm2 when compared to age- and sex-matched controls without NAAI (5.5 cm2 ± 1.3 cm2; ***p<0.001.Besides the magnitude of deceleration and direction of impact, width and height of the aortic arch are the 3rd and 4th factor directly contributing to the risk of developing traumatic NAAI in severely injured patients.

  15. 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...

  16. Evaluation of Maxillary Interpremolar, Molar Width by DRNA Indices and Arch Dimension, Arch Form in Maratha Population

    Directory of Open Access Journals (Sweden)

    Nitin Dungarwal

    2013-01-01

    Conclusion: Significant correlation was found between the sum of maxillary incisors and interpremolar width but not with the intermolar width while sum of mandibular incisors showed significant correlation with the interpremolar and intermolar arch width. There is no single arch form unique to any of the ethnic groups. A new formula is proposed to determine the premolar and molar index.

  17. Determining shapes and dimensions of dental arches for the use of straight-wire arches in lingual technique.

    Science.gov (United States)

    Kairalla, Silvana Allegrini; Scuzzo, Giuseppe; Triviño, Tarcila; Velasco, Leandro; Lombardo, Luca; Paranhos, Luiz Renato

    2014-01-01

    This study aims to determine the shape and dimension of dental arches from a lingual perspective, and determine shape and size of a straight archwire used for lingual Orthodontics. The study sample comprised 70 Caucasian Brazilian individuals with normal occlusion and at least four of Andrew's six keys. Maxillary and mandibular dental casts were digitized (3D) and the images were analyzed by Delcam Power SHAPET 2010 software. Landmarks on the lingual surface of teeth were selected and 14 measurements were calculated to determine the shape and size of dental arches. Shapiro-Wilk test determined small arch shape by means of 25th percentile (P25%)--an average percentile for the medium arch; and a large one determined by means of 75th percentile (P75%). T-test revealed differences between males and females in the size of 12 dental arches. The straight-wire arch shape used in the lingual straight wire technique is a parabolic-shaped arch, slightly flattened on its anterior portion. Due to similarity among dental arch sizes shown by males and females, a more simplified diagram chart was designed.

  18. Determining shapes and dimensions of dental arches for the use of straight-wire arches in lingual technique

    Directory of Open Access Journals (Sweden)

    Silvana Allegrini Kairalla

    2014-10-01

    Full Text Available INTRODUCTION: This study aims to determine the shape and dimension of dental arches from a lingual perspective, and determine shape and size of a straight archwire used for lingual Orthodontics. METHODS: The study sample comprised 70 Caucasian Brazilian individuals with normal occlusion and at least four of Andrew's six keys. Maxillary and mandibular dental casts were digitized (3D and the images were analyzed by Delcam Power SHAPET 2010 software. Landmarks on the lingual surface of teeth were selected and 14 measurements were calculated to determine the shape and size of dental arches. RESULTS: Shapiro-Wilk test determined small arch shape by means of 25th percentile (P25% - an average percentile for the medium arch; and a large one determined by means of 75th percentile (P75%. T-test revealed differences between males and females in the size of 12 dental arches. CONCLUSION: The straight-wire arch shape used in the lingual straight wire technique is a parabolic-shaped arch, slightly flattened on its anterior portion. Due to similarity among dental arch sizes shown by males and females, a more simplified diagram chart was designed.

  19. Use of isotopes techniques during the life cycle of dams and reservoirs: cases in Latin American

    International Nuclear Information System (INIS)

    Leon, S.H.

    2006-01-01

    In fact, the combined use of isotope and conventional techniques is considered a reliable tool for studying problems related to dam safety and has become a new culture for civil / dam engineers, hydro geologists and researchers who involve in water resource management fields. The use of natural (environmental) and artificial isotopes as tracers together with systematic analyses of the hydrochemistry, electrical conductivity and temperature profiles data during the investigation and monitoring of leakage and seepage in dams and reservoirs are now becoming popular among the dam owners in seeking the best solution for dam related problems. Many studies and experiences worldwide on effective dam management programmes have indicated that any investigation about leakages and seepages are not possible to be accomplished successfully without synergic application of the conventional technologies and isotopic techniques. The major advancement in this area is the measurements study for establishment of baseline hydrogeology at each hydraulic work project like dams and reservoirs. The parameters include hydro chemicals, isotopic and geologic in each basin, river, reservoir, dams, tunnels and groundwater which provide high value information for decision making during all the stages in the life cycle of the dams. Many hydroelectric and water supply projects in latin america apply these investigation strategies. The main target is to investigate and understand the water movement around the dam and its vicinity. Then the specialised work teams will decide for the effective and economic monitoring activities and the implementation of the recommended remedial measures to ensure high standards of safety and security of the large dams and reservoirs. A typical example of specific leakage investigation of la Honda dam is briefly discussed. (Author)

  20. Effects of dams and geomorphic context on riparian forests of the Elwha River, Washington

    Science.gov (United States)

    Shafroth, Patrick B.; Perry, Laura G; Rose, Chanoane A; Braatne, Jeffrey H

    2016-01-01

    Understanding how dams affect the shifting habitat mosaic of river bottomlands is key for protecting the many ecological functions and related goods and services that riparian forests provide and for informing approaches to riparian ecosystem restoration. We examined the downstream effects of two large dams on patterns of forest composition, structure, and dynamics within different geomorphic contexts and compared them to upstream reference conditions along the Elwha River, Washington, USA. Patterns of riparian vegetation in river segments downstream of the dams were driven largely by channel and bottomland geomorphic responses to a dramatically reduced sediment supply. The river segment upstream of both dams was the most geomorphically dynamic, whereas the segment between the dams was the least dynamic due to substantial channel armoring, and the segment downstream of both dams was intermediate due to some local sediment supply. These geomorphic differences were linked to altered characteristics of the shifting habitat mosaic, including older forest age structure and fewer young Populus balsamifera subsp. trichocarpa stands in the relatively static segment between the dams compared to more extensive early-successional forests (dominated by Alnus rubra and Salix spp.) and pioneer seedling recruitment upstream of the dams. Species composition of later-successional forest communities varied among river segments as well, with greater Pseudotsuga menziesii and Tsuga heterophylla abundance upstream of both dams, Acer spp. abundance between the dams, and P. balsamifera subsp. trichocarpa and Thuja plicata abundance below both dams. Riparian forest responses to the recent removal of the two dams on the Elwha River will depend largely on channel and geomorphic adjustments to the release, transport, and deposition of the large volume of sediment formerly stored in the reservoirs, together with changes in large wood dynamics.

  1. EVALUASI KEAMANAN DAM JATILUHUR BERBASIS INDEKS RESIKO

    Directory of Open Access Journals (Sweden)

    Avazbek Ishbaev

    2014-12-01

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

  2. 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.)

  3. 78 FR 62627 - Sam Rayburn Dam Rate

    Science.gov (United States)

    2013-10-22

    ..., Wholesale Rates for Hydro Power and Energy Sold to Sam Rayburn Dam Electric Cooperative, Inc. (Contract No... Schedule SRD-08, Wholesale Rates for Hydro Power and Energy Sold to Sam Rayburn Dam Electric Cooperative... ADMINISTRATION RATE SCHEDULE SRD-13 \\1\\ WHOLESALE RATES FOR HYDRO POWER AND ENERGY SOLD TO SAM RAYBURN DAM...

  4. Seismic Fortification Analysis of the Guoduo Gravity Dam in Tibet, China

    Directory of Open Access Journals (Sweden)

    Peng Lin

    2015-01-01

    Full Text Available The primary aim of this research was to analyze the seismic performance of the Guoduo gravity dam. A nonlinear FEM method was implemented to study the deformation, stress, and overall stability of dam under both static and dynamic loading conditions, including both normal and overloading conditions. A dam seismic failure risk control method is proposed based on the cracking mechanism induced by the dynamic load to ensure dam safety and stability. Numerical simulation revealed that (1 under normal static and dynamic loading the symmetry of the displacement distributions is good, showing that the dam abutments and riverbed foundation have good overall stiffness. The stress distribution is a safe one for operation under both normal water loading and seismic loading. (2 Attention should be paid to the reinforcement design of outlets of the diversion dam monoliths, and enhance the capability of sustaining that tensile stress of dam monoliths. (3 The shape of the dam profile has a significant effect on the dynamic response of the dam. (4 By employing the “overload safety factor method,” the overall seismic fortification is as follows: K1=1.5, K2= 2~3, and K3= 3~4.

  5. Arching in three-dimensional clogging

    Science.gov (United States)

    Török, János; Lévay, Sára; Szabó, Balázs; Somfai, Ellák; Wegner, Sandra; Stannarius, Ralf; Börzsönyi, Tamás

    2017-06-01

    Arching in dry granular material is a long established concept, however it remains still an open question how three-dimensional orifices clog. We investigate by means of numerical simulations and experimental data how the outflow creates a blocked configuration of particles. We define the concave surface of the clogged dome by two independent methods (geometric and density based). The average shape of the cupola for spheres is almost a hemisphere but individual samples have large holes in the structure indicating a blocked state composed of two-dimensional force chains rather than three-dimensional objects. The force chain structure justifies this assumption. For long particles the clogged configurations display large variations, and in certain cases the empty region reaches a height of 5 hole diameters. These structures involve vertical walls consisting of horizontally placed stable stacking of particles.

  6. Lymphoepithelial cyst in the palatoglossus arch

    Directory of Open Access Journals (Sweden)

    Evanice Maria Marçal Vieira

    2012-12-01

    Full Text Available The objective of this study was to describe a case of a lymphoepithelial cyst in the palatoglossus arch. A 16-years-old black man said that he was observed a lesion in his mouth. On the physical exam, a pedicled, consistent, smooth surface 1.5 x 1 cm lesion, similar in color to the adjacent mucosa, was found. The lesion was surgically removed and the microscopic exam showed mucosal fragments with pedicled lesion; the cystic cavity sometimes lined with pseudostratified cylindrical epithelium and others with stratified squamous flat interface of the epithelium. Around the cyst, a well-delimited mass of lymphoid tissue, presenting lymphoid follicles, was also seen. Lymphoepithelial cyst has clinical characteristics similar to those of others lesions that occur in the oral cavity. The diagnosis should be based on conservative biopsy, with total removal of lesion.

  7. Dam's design continues throughout construction

    Energy Technology Data Exchange (ETDEWEB)

    Lara E, R; Wulff, J G

    1979-11-01

    In spite of adverse site conditions, Arenal dam in Costa Rica was completed a year ahead of schedule. Historical data on local earthquake activity which was available in unusual detail reduced some uncertainties in design information. Other uncertainties regarding the complex foundation conditions were resolved as excavation and construction progressed.

  8. Building a DAM To Last: Archiving Digital Assets.

    Science.gov (United States)

    Zeichick, Alan

    2003-01-01

    Discusses archiving digital information and the need for organizations to develop policies regarding digital asset management (DAM) and storage. Topics include determining the value of digital assets; formats of digital information; use of stored information; and system architecture, including hardware and asset management software. (LRW)

  9. Dam owner floodplain management: responsibility, consequences and strategies in a competitive environment

    International Nuclear Information System (INIS)

    Joyner, J.B.; Lence, B.J.

    1999-01-01

    Dam owners responsibilities regarding dam construction, operation, maintenance, and eventual decommissioning, as imposed by various statutes in British Columbia, are discussed. The discussion includes consideration of consequences of failure to meet mandated responsibilities, and technical, legal and educational strategies to avoid exposure to risk. Recent court decisions are examined to identify common areas of risk. 9 refs., 1 fig

  10. Fuse or die: how to survive the loss of Dam in Vibrio cholerae

    DEFF Research Database (Denmark)

    Val, Marie-Eve; Kennedy, Sean P; Soler-Bistue, Alfonso J.

    2014-01-01

    Dam methylates GATC sequences in γ-proteobacteria genomes, regulating several cellular functions including replication. In Vibrio cholerae, which has two chromosomes, Dam is essential for viability, owing to its role in chr2 replication initiation. In this study, we isolated spontaneous mutants o...

  11. Research on Safety Factor of Dam Slope of High Embankment Dam under Seismic Condition

    Directory of Open Access Journals (Sweden)

    Li Bin

    2015-01-01

    Full Text Available With the constant development of construction technology of embankment dam, the constructed embankment dam becomes higher and higher, and the embankment dam with its height over 200m will always adopt the current design criteria of embankment dam only suitable for the construction of embankment dam lower than 200m in height. So the design criteria of high embankment dam shall be improved. We shall calculate the stability and safety factors of dam slope of high embankment dam under different dam height, slope ratio and different seismic intensity based on ratio of safety margin, and clarify the change rules of stability and safety factors of dam slope of high embankment dam with its height over 200m. We calculate the ratio of safety margin of traditional and reliable method by taking the stable, allowable and reliability index 4.2 of dam slope of high embankment dam with its height over 200m as the standard value, and conduct linear regression for both. As a result, the conditions, where 1.3 is considered as the stability and safety factors of dam slope of high embankment dam with its height over 200m under seismic condition and 4.2 as the allowable and reliability index, are under the same risk control level.

  12. Trading river services: optimizing dam decisions at the basin scale to improve socio-ecological resilience

    Science.gov (United States)

    Roy, S. G.; Gold, A.; Uchida, E.; McGreavy, B.; Smith, S. M.; Wilson, K.; Blachly, B.; Newcomb, A.; Hart, D.; Gardner, K.

    2017-12-01

    Dam removal has become a cornerstone of environmental restoration practice in the United States. One outcome of dam removal that has received positive attention is restored access to historic habitat for sea-run fisheries, providing a crucial gain in ecosystem resilience. But dams also provide stakeholders with valuable services, and uncertain socio-ecological outcomes can arise if there is not careful consideration of the basin scale trade offs caused by dam removal. In addition to fisheries, dam removals can significantly affect landscape nutrient flux, municipal water storage, recreational use of lakes and rivers, property values, hydroelectricity generation, the cultural meaning of dams, and many other river-based ecosystem services. We use a production possibility frontiers approach to explore dam decision scenarios and opportunities for trading between ecosystem services that are positively or negatively affected by dam removal in New England. Scenarios that provide efficient trade off potentials are identified using a multiobjective genetic algorithm. Our results suggest that for many river systems, there is a significant potential to increase the value of fisheries and other ecosystem services with minimal dam removals, and further increases are possible by including decisions related to dam operations and physical modifications. Run-of-river dams located near the head of tide are often found to be optimal for removal due to low hydroelectric capacity and high impact on fisheries. Conversely, dams with large impoundments near a river's headwaters can be less optimal for dam removal because their value as nitrogen sinks often outweighs the potential value for fisheries. Hydropower capacity is negatively impacted by dam removal but there are opportunities to meet or exceed lost capacity by upgrading preserved hydropower dams. Improving fish passage facilities for dams that are critical for safety or water storage can also reduce impacts on fisheries. Our

  13. Bovine aortic arch: A novel association with thoracic aortic dilation

    International Nuclear Information System (INIS)

    Malone, C.D.; Urbania, T.H.; Crook, S.E.S.; Hope, M.D.

    2012-01-01

    Aim: To investigate whether there is a link between bovine arch and thoracic aortic aneurysm. Materials and methods: Computed tomography (CT) and magnetic resonance imaging (MRI) images of the thorax of 191 patients with dilated thoracic aortas and 391 consecutive, unselected patients as controls were retrospectively reviewed. Bovine arch was considered present if either a shared origin of the left common carotid and innominate arteries or an origin of the left common carotid from the innominate artery was identified. A chi-square test was used to evaluate the significance of differences between subgroups. Results: A trend towards increased prevalence of bovine arch was seen in patients with dilated aortas (26.2%) compared to controls (20.5%, p = 0.12). The association was statistically significant in patients over 70 years old (31.9%, p = 0.019) and when dilation involved the aortic arch (47.6%, p = 0.003). Conclusions: An association between bovine arch and aortic dilation is seen in older patients, and when dilation involves the aortic arch. Bovine arch should be considered a potential risk factor for thoracic aortic aneurysm.

  14. Digital models: How can dental arch form be verified chairside?

    Directory of Open Access Journals (Sweden)

    Alana Tavares

    Full Text Available ABSTRACT Introduction: Plaster dental casts are routinely used during clinical practice to access maxillary dental arch form and assist on fabrication of individualized orthodontic archwires. Recently introduced, digital model technology may offer a limitation for the obtainment of a dental physical record. In this context, a tool for dental arch form assessment for chairside use is necessary when employing digital models. In this regard, paper print of the dental arch seems thus to be useful. Methods: In the present study, 37 lower arch models were used. Intercanine and intermolar widths and dental arch length measurements were performed and compared using plaster dental casts, digital models and paper print image of the models. Ortho Insight 3D scanner was employed for model digitalization. Results: No statistically significant differences were noted regarding the measurements performed on the plaster or digital models (p> 0.05. Paper print images, however, showed subestimated values for intercanine and intermolar widths and overestimated values for dental arch length. Despite being statistically significant (p< 0.001, the differences were considered clinically negligible. Conclusion: The present study suggests that paper print images obtained from digital models are clinically accurate and can be used as a tool for dental arch form assessment for fabrication of individualized orthodontic archwires.

  15. Digital models: How can dental arch form be verified chairside?

    Science.gov (United States)

    Tavares, Alana; Braga, Emanuel; de Araújo, Telma Martins

    2017-01-01

    ABSTRACT Introduction: Plaster dental casts are routinely used during clinical practice to access maxillary dental arch form and assist on fabrication of individualized orthodontic archwires. Recently introduced, digital model technology may offer a limitation for the obtainment of a dental physical record. In this context, a tool for dental arch form assessment for chairside use is necessary when employing digital models. In this regard, paper print of the dental arch seems thus to be useful. Methods: In the present study, 37 lower arch models were used. Intercanine and intermolar widths and dental arch length measurements were performed and compared using plaster dental casts, digital models and paper print image of the models. Ortho Insight 3D scanner was employed for model digitalization. Results: No statistically significant differences were noted regarding the measurements performed on the plaster or digital models (p> 0.05). Paper print images, however, showed subestimated values for intercanine and intermolar widths and overestimated values for dental arch length. Despite being statistically significant (p< 0.001), the differences were considered clinically negligible. Conclusion: The present study suggests that paper print images obtained from digital models are clinically accurate and can be used as a tool for dental arch form assessment for fabrication of individualized orthodontic archwires. PMID:29364382

  16. The Sulphate Effect on Lijiaxia Concrete Dam (China Gallery

    Directory of Open Access Journals (Sweden)

    Xufen Zhu

    2017-01-01

    Full Text Available The concrete degradation is one of the most serious problems for a dam construct during the normal operation, which determines the dam service life. Hence, it is very important to reduce the extent of the dam concrete degradation for the safety of the dam normal operation. Here, Lijiaxia hydroelectric station is taken as an example, and a comprehensive method to assess the sulphate effect on dam gallery is proposed. Eleven samples in total were taken from three difference locations by the drill bore. The microstructural investigations including X-ray fluorescence spectrometry (XRF, X-ray diffraction (XRD, scanning electron microscope (SEM, and energy dispersive spectroscopy (EDS were conducted to assess the sulphate attack and the degradation degree. Meanwhile, the water chemical analysis was applied to reveal the mechanism of concrete degradation. The experimental and analysis results indicate that the concrete degradation degree varies with the location of the samples. The components of the concrete change and the content of SO3 increase dramatically during degradation. Moreover, the mineral facies of the concrete change correspondingly, with the cement paste substituted by the calcite, calcium vitriol, and gypsum. The reinforcement and precaution measures are suggested based on the results of the degradation assessment.

  17. Large Dam Effects on Flow Regime and Hydraulic Parameters of river (Case study: Karkheh River, Downstream of Reservoir Dam

    Directory of Open Access Journals (Sweden)

    Farhang Azarang

    2017-06-01

    Full Text Available Introduction: The critical role of the rivers in supplying water for various needs of life has led to engineering identification of the hydraulic regime and flow condition of the rivers. Hydraulic structures such dams have inevitable effects on their downstream that should be well investigated. The reservoir dams are the most important hydraulic structures which are the cause of great changes in river flow conditions. Materials and Methods: In this research, an accurate assessment was performed to study the flow regime of Karkheh river at downstream of Karkheh Reservoir Dam as the largest dam in Middle East. Karkheh River is the third waterful river of Iran after Karun and Dez and the third longest river after the Karun and Sefidrud. The Karkheh Dam is a large reservoir dam built in Iran on the Karkheh River in 2000. The Karkheh Reservoir Dam is on the Karkheh River in the Northwestern Khouzestan Province, the closest city being Andimeshk to the east. The part of Karkheh River, which was studied in this research is located at downstream of Karkheh Reservoir Dam. This interval is approximately 94 km, which is located between PayePol and Abdolkhan hydrometric stations. In this research, 138 cross sections were used along Karkheh River. Distance of cross sections from each other was 680m in average. The efficient model of HEC-RAS has been utilized to simulate the Karkheh flow conditions before and after the reservoir dam construction using of hydrometric stations data included annually and monthly mean discharges, instantaneous maximum discharges, water surface profiles and etc. Three defined discharges had been chosen to simulate the Karkheh River flow; maximum defined discharge, mean defined discharge and minimum defined discharge. For each of these discharges values, HEC-RAS model was implemented as a steady flow of the Karkheh River at river reach of study. Water surface profiles of flow, hydraulic parameters and other results of flow regime in

  18. Battle looms over hydroelectric dam relicensing

    International Nuclear Information System (INIS)

    Simpson, J.

    1993-01-01

    Environmental groups, buoyed by support from influential lawmakers, are vowing to change the Federal Energy Regulatory Commission's (FERC's) hydroelectric relicensing procedures. For too long, the groups say, the hydroelectric industry has benefitted from a cozy relationship with the FERC, which has emphasized economic over environmental considerations. The success or failure of the environmentalists agenda will likely prove critical to the hydroelectric industry. With 237 hydroelectric licenses up for renewal this year - the most ever considered by the FERC in one year - and four vacant seats at the Commission, FERC hydro policy appears poised for upheaval. The groups have proposed a multipoint program to address perceived shortcomings in the FERC's hydroelectric relicensing procedures. The program includes recommendations to: Shorten dam licenses (which currently stretch 30 to 50 years) and require the FERC to periodically reevaluate the terms of hydropower licenses; Increase Congressional oversight of the FERC to assure adherence to environmental laws, including the National Environmental Policy Act, which mandates the preparation of environmental impact statements where appropriate; Mandate facilities for upstream and downstream fish passage; Establish a mitigation fund, collectable from dam owners, for river conservation and restoration programs; Promote all alternatives to relicensing projects, including denial of project licenses; and Reassign the FERC's hydropower jurisdiction to another federal agency, such as the Environmental Protection Agency or the Department of the Interior

  19. How far is the root apex of a unilateral impacted canine from the root apices' arch form?

    Science.gov (United States)

    Kim, Sung-Hun; Kim, You-Min; Oh, Sewoong; Kim, Seong-Sik; Park, Soo-Byung; Son, Woo-Sung; Kim, Yong-Il

    2017-02-01

    The purpose of this study was to determine the arch form of the root apices of normally erupting teeth and then determine the differences in the location of the apex of impacted canines relative to normally erupting canines. In addition, we sought to determine whether the labiopalatal position of the impacted canines influences the position of the apices. The study included 21 patients with unerupted canines that subsequently had a normal eruption, 21 patients with palatally impacted canines, 27 patients with labially impacted canines, and 17 patients with midalveolus impacted canines. Images were obtained using cone beam computed tomography, and the x, y, and z coordinates of the root apices were determined using Ondemand3D software (Cybermed Co., Seoul, Korea). Two-dimensional coordinates were converted from acquired 3-dimensional coordinates via projection on a palatal plane, and the Procrustes method was used to process the converted 2-dimensional coordinates and to draw the arch forms of the root apices. Finally, we measured the extent of root apex deviation from the arch forms of the root apices. Normally erupting canines showed that even though calcifications may be immature, their positions were aligned with a normal arch form. The root apices of the impacted canines were an average of 6.572 mm away from the root apices' arch form, whereas those of the contralateral nonimpacted canines were an average distance of 2.221 mm away, a statistically significant difference. The palatally impacted canines' root apices distribution tended toward the first premolar root apices. Incompletely calcified, unerupted teeth with a subsequent normal eruption showed a normal arch form of the root apices. The root apices of impacted canines were farther from the arch forms than were the nonimpacted canines. Also, the root apices of impacted canines in the palatal area showed distributions different from those of the other impacted canine groups. Copyright © 2017 American

  20. Morphological and dimensional characteristics of dental arch in children with beta thalassemia major

    Directory of Open Access Journals (Sweden)

    Disha Kumar

    2018-01-01

    Full Text Available Background and Objectives: The aim of this study was to examine the arch dimensions of beta thalassemia major patients in comparison with normal individuals. Materials and Methods: Dental arch dimensions were compared between thalassemic patients and normal individuals in the age group of 12–16 years in the maxillary and mandibular arch corresponding to each other regarding age, sex and Angle's molar relationship. A total number of sixty cases in each group were taken. Maxillary and mandibular impressions were made with alginate for all the sixty participants in each group and poured with die stone. Measurement of inter incisor, inter canine, inter premolar and intermolar arch width, arch depth, right anterior, right posterior, left anterior, and left posterior arch length was carried out from each cast using digital Vernier caliper.Results: Unpaired t-test was used for comparison between the two groups. Statistically, a significant difference was found between the case and control groups in the maxillary arch in intercanine width, inter premolar width, intermolar width, right anterior arch length, right posterior arch length, and left anterior arch length. However, no statistically significant difference was found between the groups in inter incisor width, left posterior arch length, and arch depth in the maxillary arch. In the mandibular arch, statistically significant difference was found between the case and control groups in inter canine width, inter premolar width, inter molar width, and left anterior arch length. However, no statistically significant difference was found between the case and control groups in the mandibular arch in interincisor width, right anterior arch length, right posterior arch length, and left posterior arch length. Conclusion: Dental arch widths and arch lengths were significantly reduced in thalassemic patients as compared to normal individuals for the maxillary and mandibular arches.

  1. New guidelines for dam safety classification

    International Nuclear Information System (INIS)

    Dascal, O.

    1999-01-01

    Elements are outlined of recommended new guidelines for safety classification of dams. Arguments are provided for the view that dam classification systems should require more than one system as follows: (a) classification for selection of design criteria, operation procedures and emergency measures plans, based on potential consequences of a dam failure - the hazard classification of water retaining structures; (b) classification for establishment of surveillance activities and for safety evaluation of dams, based on the probability and consequences of failure - the risk classification of water retaining structures; and (c) classification for establishment of water management plans, for safety evaluation of the entire project, for preparation of emergency measures plans, for definition of the frequency and extent of maintenance operations, and for evaluation of changes and modifications required - the hazard classification of the project. The hazard classification of the dam considers, as consequence, mainly the loss of lives or persons in jeopardy and the property damages to third parties. Difficulties in determining the risk classification of the dam lie in the fact that no tool exists to evaluate the probability of the dam's failure. To overcome this, the probability of failure can be substituted for by a set of dam characteristics that express the failure potential of the dam and its foundation. The hazard classification of the entire project is based on the probable consequences of dam failure influencing: loss of life, persons in jeopardy, property and environmental damage. The classification scheme is illustrated for dam threatening events such as earthquakes and floods. 17 refs., 5 tabs

  2. Research on shape optimization of CSG dams

    Directory of Open Access Journals (Sweden)

    Xin Cai

    2011-12-01

    Full Text Available The multi-objective optimization method was used for shape optimization of cement sand and gravel (CSG dams in this study. The economic efficiency, the sensitivities of maximum horizontal displacement and maximum settlement of the dam to water level changes, the overall stability, and the overall strength security were taken into account during the optimization process. Three weight coefficient selection schemes were adopted to conduct shape optimization of a dam, and the case studies lead to the conclusion that both the upstream and downstream dam slope ratios for the optimal cross-section equal 1:0.7, which is consistent with the empirically observed range of 1:0.6 to 1:0.8 for the upstream and downstream dam slope ratios of CSG dams. Therefore, the present study is of certain reference value for designing CSG dams.

  3. Dynamic tests at the Outardes 3 dam

    International Nuclear Information System (INIS)

    Proulx, J.; Paultre, P.; Duron, Z.; Tai Mai Phat; Im, O.

    1992-01-01

    At the Outardes 3 gravity dam, part of the Manicouagan-Outardes hydroelectric complex in northeastern Quebec, forced vibration tests were carried out using an eccentric mass shaker attached to the dam crest at three different locations. Accelerations were measured along the crest and in the inspection galleries, and hydrodynamic pressures were measured along the upstream dam face and at various locations in the reservoir. The tests were designed to analyze the effects of gravity dam-reservoir interactions and to generate a data base for calibrating finite element models used in studying the dynamic behavior of gravity dams. Experimental results are presented in order to demonstrate the quality of the data obtained and the effectiveness of the experimental procedures. Modes of vibration were observed which corresponded to those obtained by finite element analysis. It is shown that techniques recently developed for dynamic tests on large dams can be successfully used on gravity dams. 3 refs., 6 figs

  4. Putting Roman Dams in Context: a Virtual Approach

    Science.gov (United States)

    Decker, M. J.; Du Vernay, J. P.; Mcleod, J. B.

    2017-08-01

    innovative perspective on a long time studied monument. In this paper it will be explored how deploying recent computer technologies to the Roman dam at Consuegra can advance our understanding of the history of local and regional landscape change and the technology of water management. In summer 2016, the dam has been documented with terrestrial laser scanning with two FARO Focus 3D x330 and aerial photogrammetry image capturing with a DJI Phantom 4 drone. Data was processed in various 3D software applications to generate 3D representations of the dam including 3D point clouds, animations, and meshed models.

  5. Crozat appliance therapy for an arch-length discrepancy problem.

    Science.gov (United States)

    Parker, M

    1991-01-01

    The case involved a white male subject, aged 10 years 6 months, with a Class I molar relationship complicated by a deep overbite and impaction of all four permanent canines, which were completely blocked out of the arches. The growth rate of the arches was found to be abnormal, and there was premature loss of the deciduous teeth. Over a period of approximately 5 years, with intermittent pauses to allow growth to catch up with treatment, the Crozat removable appliance was used to help establish the arch form and correct the plane of occlusion.

  6. Environmental risk assessment system for phosphogypsum tailing dams.

    Science.gov (United States)

    Sun, Xin; Ning, Ping; Tang, Xiaolong; Yi, Honghong; Li, Kai; Zhou, Lianbi; Xu, Xianmang

    2013-01-01

    This paper may be of particular interest to the readers as it provides a new environmental risk assessment system for phosphogypsum tailing dams. In this paper, we studied the phosphogypsum tailing dams which include characteristics of the pollution source, environmental risk characteristics and evaluation requirements to identify the applicable environmental risk assessment methods. Two analytical methods, that is, the analytic hierarchy process (AHP) and fuzzy logic, were used to handle the complexity of the environmental and nonquantitative data. Using our assessment method, different risk factors can be ranked according to their contributions to the environmental risk, thereby allowing the calculation of their relative priorities during decision making. Thus, environmental decision-makers can use this approach to develop alternative management strategies for proposed, ongoing, and completed PG tailing dams.

  7. Study of Dam-break Due to Overtopping of Four Small Dams in the Czech Republic

    Directory of Open Access Journals (Sweden)

    Zakaraya Alhasan

    2015-01-01

    Full Text Available Dam-break due to overtopping is one of the most common types of embankment dam failures. During the floods in August 2002 in the Czech Republic, several small dams collapsed due to overtopping. In this paper, an analysis of the dam break process at the Luh, Velký Bělčický, Melín, and Metelský dams breached during the 2002 flood is presented. Comprehensive identification and analysis of the dam shape, properties of dam material and failure scenarios were carried out after the flood event to assemble data for the calibration of a numerical dam break model. A simple one-dimensional mathematical model was proposed for use in dam breach simulation, and a computer code was compiled. The model was calibrated using the field data mentioned above. Comparison of the erodibility parameters gained from the model showed reasonable agreement with the results of other authors.

  8. Assessment of the risk of drowning at low-head dams used as sea lamprey barriers in Ontario[Includes the CSCE forum on professional practice and career development : 1. international engineering mechanics and materials specialty conference : 1. international/3. coastal, estuarine and offshore engineering specialty conference : 2. international/8. construction specialty conference

    Energy Technology Data Exchange (ETDEWEB)

    Mazurek, K.A.; Thomson, J.; Amos, M. [Saskatchewan Univ., Saskatoon, SK (Canada). Dept. of Civil and Geological Engineering; Hallett, A. [A. Hallett, Sault Ste. Marie, ON (Canada); Aktar, A. [Indian Inst. of Technology, Kanpur (India). Dept. of Civil Engineering; Katopodis, C. [Fisheries and Oceans Canada, Winnipeg, MB (Canada). Freshwater Inst.

    2009-07-01

    In 2003, there were 54 fixed-crest lamprey barriers used in the Great Lakes region, with more construction planned. Although the barriers are relatively small structures of about 1-2 m in height, they present a drowning hazard. On the downstream side of the structure, a submerged hydraulic jump creates a strong vortex flow that even an experienced swimmer cannot escape. This study developed a method to assess the risk of hazardous flows at the barrier sites to enable dam owners to decide whether or not mitigative measures need to be undertaken at their sites. This hazard assessment was demonstrated for 2 existing lamprey barriers in Ontario, namely the Duffins Creek Barrier at Ajax and the Little Otter Creek Barrier near Straffordville. However, the work can be applied to the dam safety assessment and the development of potential mitigative strategies for drowning at other low-head dams and weirs. A flow-duration curves was developed for each site in order to determine the risk of having a drowning hazard at the barrier sites. In the flow-duration analysis, the percentage time, or probability, that a given flow rate was equalled or exceeded was calculated directly from observations of the average daily discharge in the channel. 18 refs., 1 tab., 7 figs.

  9. The Potential for Dams to Impact Lowland Meandering River Floodplain Geomorphology

    Directory of Open Access Journals (Sweden)

    Philip M. Marren

    2014-01-01

    Full Text Available The majority of the world's floodplains are dammed. Although some implications of dams for riverine ecology and for river channel morphology are well understood, there is less research on the impacts of dams on floodplain geomorphology. We review studies from dammed and undammed rivers and include influences on vertical and lateral accretion, meander migration and cutoff formation, avulsion, and interactions with floodplain vegetation. The results are synthesized into a conceptual model of the effects of dams on the major geomorphic influences on floodplain development. This model is used to assess the likely consequences of eight dam and flow regulation scenarios for floodplain geomorphology. Sediment starvation downstream of dams has perhaps the greatest potential to impact on floodplain development. Such effects will persist further downstream where tributary sediment inputs are relatively low and there is minimal buffering by alluvial sediment stores. We can identify several ways in which floodplains might potentially be affected by dams, with varying degrees of confidence, including a distinction between passive impacts (floodplain disconnection and active impacts (changes in geomorphological processes and functioning. These active processes are likely to have more serious implications for floodplain function and emphasize both the need for future research and the need for an “environmental sediment regime” to operate alongside environmental flows.

  10. The potential for dams to impact lowland meandering river floodplain geomorphology.

    Science.gov (United States)

    Marren, Philip M; Grove, James R; Webb, J Angus; Stewardson, Michael J

    2014-01-01

    The majority of the world's floodplains are dammed. Although some implications of dams for riverine ecology and for river channel morphology are well understood, there is less research on the impacts of dams on floodplain geomorphology. We review studies from dammed and undammed rivers and include influences on vertical and lateral accretion, meander migration and cutoff formation, avulsion, and interactions with floodplain vegetation. The results are synthesized into a conceptual model of the effects of dams on the major geomorphic influences on floodplain development. This model is used to assess the likely consequences of eight dam and flow regulation scenarios for floodplain geomorphology. Sediment starvation downstream of dams has perhaps the greatest potential to impact on floodplain development. Such effects will persist further downstream where tributary sediment inputs are relatively low and there is minimal buffering by alluvial sediment stores. We can identify several ways in which floodplains might potentially be affected by dams, with varying degrees of confidence, including a distinction between passive impacts (floodplain disconnection) and active impacts (changes in geomorphological processes and functioning). These active processes are likely to have more serious implications for floodplain function and emphasize both the need for future research and the need for an "environmental sediment regime" to operate alongside environmental flows.

  11. Will river erosion below the Three Gorges Dam stop in the middle Yangtze?

    Science.gov (United States)

    Lai, X.; Yin, D.; Finlayson, B. L.; Wei, T.; Li, M.; Yuan, W.; Yang, S.; Dai, Z.; Gao, S.; Chen, Z.

    2017-11-01

    The environmental impact of the Three Gorges Dam has been a subject of vigorous academic, political and social debate since its inception. This includes the key issue of post-dam river channel erosion, which was predicted by the feasibility study to extend to the river mouth. In this paper we examine the geomorphic response of the channel of the middle Yangtze for 660 km downstream of the dam. Using data on channel characteristics, bed material and sediment transport, we show that in the decade following the dam closure, pre-dam seasonal erosion has been replaced by year-round erosion, a pattern most marked at the upstream end of the study area. The sediment carrying capacity of the river channel has been largely reduced below the dam. The locus of bed scour has moved progressively downstream, ceasing as the bed material became too coarse to be transported (e.g. D50: 0.29 mm pre-dam coarsened to 20 mm below the dam by 2008). About 400 km below the dam there is a reduction in channel slope that changes the sediment carrying capacity from 0.25 kg m-3 to only about 0.05 kg m-3, which is insufficient to move bed sediment. The new long-term hydro-morphological equilibrium that will be established in this section of the middle Yangtze will prevent the further incision downstream initiated by the Three Gorges Dam. The results suggest that the full extent of adverse environmental impact predicted by the pre-dam studies will not eventuate.

  12. Plastic collapse load of crown-hinged steel circular arches : a theoretical method

    NARCIS (Netherlands)

    Spoorenberg, R.C.; Snijder, H.H.; Hoenderkamp, J.C.D.

    2013-01-01

    For construction purposes and to avoid detrimental influences of foundation settlements arches are not always made from a single arch-rib but are built by connecting two curvilinear elements at the crown with a hinge. These arches are also known as crown-hinged arches. This paper presents an

  13. Arch translocation and the intra-arch elephant-trunk technique with collared graft for extended chronic dissecting aortic aneurysm

    Directory of Open Access Journals (Sweden)

    Ikenaga Shigeru

    2013-01-01

    Full Text Available Abstract Management of extensive, chronic, dissecting aortic aneurysms after prior repair of the ascending aorta presents a technical challenge for surgeons. A symptomatic 64-year-old patient was admitted for elective surgical repair of an aortic annular dilatation, causing severe aortic regurgitation, and a Crawford type II extended thoracoabdominal aneurysm, 4 years after he underwent primary repair of an acute aortic dissection. The aorta was diffusely dilated, and there were no sites beyond the distal aortic arch where anastomosis could be performed. We successfully performed total aortic replacement with a 2-stage strategy, using an arch translocation technique and an intra-arch elephant-trunk technique.

  14. Soil-fluid-structure interaction applied to the Oued Taht dam (taking into account the membrane effect.

    Directory of Open Access Journals (Sweden)

    Nasreddine Krenich

    2018-01-01

    Full Text Available The objective of this work is to analyze the dynamic behavior (modal behavior of the "Oued Taht" arch dam located at MASCARA, taking into consideration the effect of soil-fluid-structure interaction. The finite element code "Ansys" was chosen for the dynamic modeling of the dam that is the subject of this study. Three hypotheses were used for soil-structure interaction modeling; model with embedded base which corresponds to the case where the phenomenon of interactions soil-structure is neglected, model with ground of foundation without mass which consists in taking into account the kinematic component of interaction soil structure and neglecting the inertial component and the model with foundation soil with mass where the two components of soil-structure interaction are taken into account. For the fluid, the model of added masses (equivalent to the westergaard approach using the SURF element available in the Ansys code library was used. A comparison between the different models of the "Oued Taht" dam was made; it has been found that the taking into account of the soil-fluid-structure interaction phenomenon modifies the period of the system and that the modeling of the dam with and without fluid gives a very important difference of the periods. The results obtained were compared with those of the "Brezina" dam, which is a gravity dam located in BAYADH. The work has shown that the periods of the "Oued Taht" dam with soil-fluid-structure interaction modeling are very out of phase with the periods without fluid modeling (taking into account only the soilstructure interaction phenomenon. which is not the case for the Brezina dam where the periods for the two models are getting closer. The periods between the two models mentioned before are close to the dam of Brézina because the latter is a dam which participates much more by its own weight than by its vault (thickness of the vault varies between 36.3 m at the base and 5m in crest which is the

  15. Crotch Lake dam rehabilitation project

    International Nuclear Information System (INIS)

    Brunet, G.; Dobrowolski, E.

    1999-01-01

    Replacement of the existing wood crib dam structure on Crotch Lake on the Mississippi River in eastern Ontario that provided water storage for the power production at High Falls Generating Station, became necessary when it was determined that the dam did not meet Ontario-Hydro's safety standards. This paper describes the project of replacing the existing structure with a PVC coated gabion wall with waterproofing. The entire structure was covered with three layers of wire mesh, laced together, and criss-crossed for superior strength and rigidity. The work was completed in 28 days with no environmental impact . Life expectancy of the new structure is in excess of 40 years. With periodic maintenance of the gabion mat cover, life span could be extended an additional 20 to 40 years. 5 figs

  16. Detecting atheromatous plaques in the aortic arch or supra-aortic arteries for more accurate stroke subtype classification.

    Science.gov (United States)

    Cui, Xiaoyang; Wu, Simiao; Zeng, Quantao; Xiao, Jiahe; Liu, Ming

    2015-02-01

    To investigate the correlations of atheromatous plaques in the aortic arch or supra-aortic arteries with intracranial arterial stenosis and carotid plaques in stroke patients, and to determine whether taking these plaques into account will reduce the proportion of patients in the undetermined etiology group. We prospectively enrolled 308 ischemic stroke patients, whose clinical characteristics and A-S-C-O classifications were compared with analyses of intracranial arteries, carotid arteries, aortic arch, and supra-aortic arteries. 125(40.6%) patients had plaques in the aortic arch or supra-aortic arteries, of which 106 (84.8%) had complex plaques. No correlations were observed between these plaques and carotid plaques ( p = 0.283) or intracranial arterial stenosis ( p = 0.097). After detecting the mobile thrombi in the aortic arch and supra-aortic arteries, the proportion of patients in the atherothrombosis group was increased from 33.8% to 55.5% ( p = 0.00), whereas the proportion of patients in stroke of undetermined etiology group was decreased from 19.2% to 11.0% ( p = 0.00). Examining only the carotid and intracranial arteries may not provide adequate information about large arteries in stroke patients. Therefore, it would be better to include a search for relevant plaques in the aortic arch or supra-aortic arteries in modern stroke workup, for it may lead to more accurate stroke subtype classification and guide secondary prevention.

  17. Treatment planning for patients with dental arch asymmetry caused by loss of a premolar on one side of the mouth

    Directory of Open Access Journals (Sweden)

    Ivanova О.P.

    2013-09-01

    Full Text Available The objective of this study is to determine a selection criterion that is applicable for the treatment of patients with dental arch asymmetry caused by loss of a premolar on one side of the mouth. Material and methods. Fifty-seven patients (first maturity level who had some teeth extracted for orthodontic treatment were included in the study. The patients were divided into basic and control groups. We proposed to shape the extraction socket immediately after the extraction of a permanent tooth. In the basic group the extraction sockets were filled with osteoplastic material. Patients in the control group refused any surgical interventions. Results. According to a given criterion, the correlation between tooth size and dental arch parameters has been determined. When applying this criterion for finding the correlation, the frontal distal diagonal size of the dental arch was multiplied by 1.14 coefficient. The sum of the mesiodistal diameters of seven teeth in the half-arc was subtracted from the obtained value. The value which was equal to 0±1.0mm indicated the correlation between tooth size and dental arch parameters. Conclusion. If there is a correlation between tooth size and dental arch parameters, it is advisable to provide treatment associated with having the post-extraction socket opened and implant therapy performed (most commonly with the use of intraosseous dental implants.

  18. Seismic hazard and risk assessment for large Romanian dams situated in the Moldavian Platform

    Science.gov (United States)

    Moldovan, Iren-Adelina; Popescu, Emilia; Otilia Placinta, Anica; Petruta Constantin, Angela; Toma Danila, Dragos; Borleanu, Felix; Emilian Toader, Victorin; Moldoveanu, Traian

    2016-04-01

    Besides periodical technical inspections, the monitoring and the surveillance of dams' related structures and infrastructures, there are some more seismic specific requirements towards dams' safety. The most important one is the seismic risk assessment that can be accomplished by rating the dams into seismic risk classes using the theory of Bureau and Ballentine (2002), and Bureau (2003), taking into account the maximum expected peak ground motions at the dams site - values obtained using probabilistic hazard assessment approaches (Moldovan et al., 2008), the structures vulnerability and the downstream risk characteristics (human, economical, historic and cultural heritage, etc) in the areas that might be flooded in the case of a dam failure. Probabilistic seismic hazard (PSH), vulnerability and risk studies for dams situated in the Moldavian Platform, starting from Izvorul Muntelui Dam, down on Bistrita and following on Siret River and theirs affluent will be realized. The most vulnerable dams will be studied in detail and flooding maps will be drawn to find the most exposed downstream localities both for risk assessment studies and warnings. GIS maps that clearly indicate areas that are potentially flooded are enough for these studies, thus giving information on the number of inhabitants and goods that may be destroyed. Geospatial servers included topography is sufficient to achieve them, all other further studies are not necessary for downstream risk assessment. The results will consist of local and regional seismic information, dams specific characteristics and locations, seismic hazard maps and risk classes, for all dams sites (for more than 30 dams), inundation maps (for the most vulnerable dams from the region) and possible affected localities. The studies realized in this paper have as final goal to provide the local emergency services with warnings of a potential dam failure and ensuing flood as a result of an large earthquake occurrence, allowing further

  19. Vulnerability of Karangkates dams area by means of zero crossing analysis of data magnetic

    Energy Technology Data Exchange (ETDEWEB)

    Sunaryo,, E-mail: sunaryo@ub.ac.id, E-mail: sunaryo.geofis.ub@gmail.com; Susilo, Adi [Geophysics Program Study, Physics Dept., Sciences Faculty, University of Brawijaya, Malang (Indonesia)

    2015-04-24

    Study with entitled Vulnerability Karangkates Dam Area By Means of Zero Crossing Analysis of Data Magnetic has been done. The study was aimed to obtain information on the vulnerability of two parts area of Karangkates dams, i.e. Lahor dam which was inaugurated in 1977 and Sutami dam inaugurated in 1981. Three important things reasons for this study are: 1). The dam age was 36 years old for Lahor dam and 32 years old for Sutami dam, 2). Geologically, the location of the dams are closed together to the Pohgajih local shear fault, Selorejo local fault, and Selorejo limestone-andesite rocks contact plane, and 3). Karangkates dams is one of the important Hydro Power Plant PLTA with the generating power of about 400 million KWH per year from a total of about 29.373MW installed in Indonesia. Geographically, the magnetic data acquisition was conducted at coordinates (112.4149oE;-8.2028oS) to (112.4839oE;-8.0989oS) by using Proton Precession Magnetometer G-856. Magnetic Data acquisition was conducted in the radial direction from the dams with diameter of about 10 km and the distance between the measurements about 500m. The magnetic data acquisition obtained the distribution of total magnetic field value in the range of 45800 nT to 44450 nT. Residual anomalies obtained by doing some corrections, including diurnal correction, International Geomagnetic Reference Field (IGRF) correction, and reductions so carried out the distribution of the total magnetic field value in the range of -650 nT to 700 nT. Based on the residual anomalies, indicate the presence of 2 zones of closed closures dipole pairs at located in the west of the Sutami dam and the northwest of the Lahor dam from 5 total zones. Overlapping on the local geological map indicated the lineament of zero crossing patterns in the contour of residual anomaly contour with the Pohgajih shear fault where located at about 4 km to the west of the Sutami dam approximately and andesite-limestone rocks contact where located

  20. Coupled models in dam engineering

    OpenAIRE

    González Gutiérrez, María De Los Ángeles

    2016-01-01

    Rock ll dams are certainly one of the most important engineering structures due to their economic advantages and exible design. Unfortunately their vulnerability to overtopping still remains their weakest point. For that reason, several research groups are interested in both the numerical and experimental analysis of this phenomenon. In this work we focused on the numerical analysis. The previous work developed in CIMNE on a coupled PFEM-Eulerian free surface Compu- tational...

  1. Environmental monitoring at Olympic Dam

    International Nuclear Information System (INIS)

    Anon.

    1989-01-01

    The environmental management and protection program at the Olympic Dam uranium/copper/gold project, Roxby Downs, South Australia, monitors eight major environmental parameters - meteorology, vegetation, mine site rehabilitation, fauna, terrain, soil salinity, hydrogeology and well fields. It came into effect with the approval of the South Australian Government in March 1987. The Great Artesian Basin, one of the world's greatest artesian basins, is the source of the water supply for the project

  2. Assessment of Soil Arching Factor for Retaining Wall Pile Foundations

    Science.gov (United States)

    2017-03-31

    Despite the prevalence of the soldier piles retaining wall systems as temporary and even permanent shoring systems along state highways, relatively little is known on the effect of the foreslope bench width and the slope inclination on the arching ca...

  3. 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....

  4. Agenesis of the posterior arch of the atlas

    Directory of Open Access Journals (Sweden)

    Torriani Martin

    2002-01-01

    Full Text Available PURPOSE: To illustrate the radiological findings and review the current literature concerning a rare congenital abnormality of the posterior arch of the atlas. CASE REPORT: An adult female without neurological symptoms presented with an absent posterior arch of the atlas, examined with plain films and helical computerized tomography. Complete agenesis of the posterior arch of the atlas is a rare entity that can be easily identified by means of plain films. Although it is generally asymptomatic, atlantoaxial instability and neurological deficits may occur because of structural instability. Computerized tomography provides a means of assessing the extent of this abnormality and can help evaluate the integrity of neural structures. Although considered to be rare entities, defects of the posterior arch of the atlas may be discovered as incidental asymptomatic findings in routine cervical radiographs. Familiarity with this abnormality may aid medical professionals in the correct management of these cases.

  5. Axially modulated arch resonator for logic and memory applications

    KAUST Repository

    Hafiz, Md Abdullah Al; Tella, Sherif Adekunle; Alcheikh, Nouha; Fariborzi, Hossein; Younis, Mohammad I.

    2018-01-01

    We demonstrate reconfigurable logic and random access memory devices based on an axially modulated clamped-guided arch resonator. The device is electrostatically actuated and the motional signal is capacitively sensed, while the resonance frequency

  6. Behaviour of steel arch supports under dynamic effects of rockbursts

    Czech Academy of Sciences Publication Activity Database

    Horyl, P.; Šňupárek, Richard

    2007-01-01

    Roč. 116, č. 3 (2007), s. 119-128 ISSN 0371-7844 Institutional research plan: CEZ:AV0Z30860518 Keywords : steel arch support * rockbursts * dynamic loading Subject RIV: DH - Mining , incl. Coal Mining

  7. 77 FR 9265 - Glen Canyon Dam Adaptive Management Work Group

    Science.gov (United States)

    2012-02-16

    ... DEPARTMENT OF THE INTERIOR Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group... Adaptive Management Work Group (AMWG) makes recommendations to the Secretary of the Interior concerning.... L. 102-575) of 1992. The AMP includes a Federal advisory committee, the AMWG, a technical work group...

  8. Chemical characteristics and limnology of Loskop Dam on the ...

    African Journals Online (AJOL)

    Major impacts include acid mine drainage and eutrophication associated with sewage effluent. ... ensure the sustainability of Loskop Dam, catchment management plans must focus on reducing phosphorus inputs, and continue seeking treatment solutions for mine-water associated with abandoned and working coal mines.

  9. Cost of skid roads for arch logging in West Virginia

    Science.gov (United States)

    George R., Jr. Trimble; Carl R. Barr

    1960-01-01

    In the mountain hardwood country of the northern Appalachians, tree-length skidding with tractor and arch has proved to be economical logging. One essential part of this type of logging is that tree-length logs are winched to the skid roads: tractor and arch do not run around through the woods. Winching distance is commonly 200 to 300 feet; and occasionally an extra...

  10. Persistent truncus arteriosis associated with interruption of the aortic arch.

    Science.gov (United States)

    Nath, P H; Zollikofer, C; Castaneda-Zuniga, W; Formanek, A; Amplatz, K

    1980-09-01

    Five patients with a combination of truncus arteriosus and interruption of the aortic arch are reported. The combination of those defects significantly increases the surgical risk. This rare cardiac malformation can only be diagnosed radiographically. An aberrant right subclavian artery is present in 25% of patients. It is helpful in suspecting the diagnosis from plain films of the chest. The diagnosis can be made from a ventriculogram, but usually a truncogram is necessary to define the anatomy of the aortic arch.

  11. 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.

  12. Parascapular mass revealing primary tuberculosis of the posterior arch

    Science.gov (United States)

    Arbault, Anais; Ornetti, Paul; Chevallier, Olivier; Avril, Julien; Pottecher, Pierre

    2016-01-01

    We report the case of a parascapular abscess revealing primary tuberculosis of the posterior arch in a 31-year-old man. Sectional imaging is essential in order to detect the different lesions of this atypical spinal tuberculosis as osteolysis of the posterior arch extendible to vertebral body, osteocondensation, epidural extension which is common in this location, and high specificity of a zygapophysial, costo-vertebral or transverse arthritis. PMID:27709081

  13. Variations in tooth size and arch dimensions in Malay schoolchildren.

    Science.gov (United States)

    Hussein, Khalid W; Rajion, Zainul A; Hassan, Rozita; Noor, Siti Noor Fazliah Mohd

    2009-11-01

    To compare the mesio-distal tooth sizes and dental arch dimensions in Malay boys and girls with Class I, Class II and Class III malocclusions. The dental casts of 150 subjects (78 boys, 72 girls), between 12 and 16 years of age, with Class I, Class II and Class III malocclusions were used. Each group consisted of 50 subjects. An electronic digital caliper was used to measure the mesio-distal tooth sizes of the upper and lower permanent teeth (first molar to first molar), the intercanine and intermolar widths. The arch lengths and arch perimeters were measured with AutoCAD software (Autodesk Inc., San Rafael, CA, U.S.A.). The mesio-distal dimensions of the upper lateral incisors and canines in the Class I malocclusion group were significantly smaller than the corresponding teeth in the Class III and Class II groups, respectively. The lower canines and first molars were significantly smaller in the Class I group than the corresponding teeth in the Class II group. The lower intercanine width was significantly smaller in the Class II group as compared with the Class I group, and the upper intermolar width was significantly larger in Class III group as compared with the Class II group. There were no significant differences in the arch perimeters or arch lengths. The boys had significantly wider teeth than the girls, except for the left lower second premolar. The boys also had larger upper and lower intermolar widths and lower intercanine width than the girls. Small, but statistically significant, differences in tooth sizes are not necessarily accompanied by significant arch width, arch length or arch perimeter differences. Generally, boys have wider teeth, larger lower intercanine width and upper and lower intermolar widths than girls.

  14. Modified protrusion arch for anterior crossbite correction - a case report.

    Science.gov (United States)

    Roy, Abhishek Singha; Singh, Gulshan Kr; Tandon, Pradeep; Chaudhary, Ramsukh

    2013-01-01

    Borderline and mild skeletal Class III relationships in adult patients are usually treated by orthodontic camouflage. Reasonably rood results have been achieved with nonsurgical teatment of anterior crossbite. Class III malocclusion may be associated with mandibular prognathism, maxillary retrognathism, or both. Class III maxillary retrognathism generally involves anterior crossbite, which must be opened if upper labial brackets are to be bonded. If multiple teeth are in crossbite, after opening the bite usual step is to ligate forward or advancement arch made of 0.018" or 0.020" stainless steel or NiTi wire main arch that must be kept separated 2 mm from the slot ofupper incisor braces. Two stops or omegas are made 1 mm mesial to the tubes of the molar bands that will impede main arch from slipping,and in this manner the arch will push the anterior teeth forward Here we have fabricated a modified multiple loop protrusion arch to correct an anterior crossbite with severe crowding that was not amenable to correct by advancement arches.

  15. Public safety risk management at socio-economic and / or historic-cultural significant dam sites

    Energy Technology Data Exchange (ETDEWEB)

    Earle, Gordon D.; Ryan, Katherine; Pyykonen, Nicole K.; Pitts, Lucas [Otonabee Region Conservation Authority, Peterborough, (Canada)

    2010-07-01

    The Lang Dam and adjoining gristmill, located near Peterborough are integral parts of the Lang Pioneer Village museum. Activities occurring within close proximity to the dam have led to safety issues. The owner (ORCA) has developed and implemented public safety management plans (PSMPs) for each of its water control structures, including the Lang Dam. ORCA gave special attention to the social, economic, aesthetic, historic and cultural dimensions associated the implementation of public safety management plans. These factors play a significant role in how well public safety measures (PSMs) are received by stakeholder groups and the general public. This paper reported the challenges of developing and implementing a PSMP for the Lang Dam, with the focus on property site-specific PSMS while preserving socio-economic and historic-cultural character and values. It was demonstrated that the dam owners, regulatory authorities, control agencies and preservationists need to come together to develop a holistic public safety management process.

  16. TECHNICAL AND ECONOMICAL COMPARISON OF OVERFLOW DAM VARIANTS AT THE GRODNO WATER-POWER STATION

    Directory of Open Access Journals (Sweden)

    G. G. Krouglov

    2005-01-01

    Full Text Available The paper considers various aspects pertaining to determination of main technical characteristics of water-development projects of water-power stations. Technical and economical characteristics of overflow dams at the Grodno water-power station are compared in the paper.The paper contains results of model investigations of two-tier overflow dam which is included in composition of the Grodno water-power station and presents methodology for calculation of pool integration behind two-tier dam which has been developed at the water-development and power engineering department. This methodology makes it possible to determine rate coefficient and compressed depth. In addition to this the paper gives technical and economical comparison of various designs of overflow dams at the Grodno water-power station, analyzes their cost and on the basis of this comparative analysis it is recommended to construct a two-pier dam

  17. Multiyear Downstream Response to Dam Removal on the White Salmon River, WA

    Science.gov (United States)

    Wilcox, A. C.; O'Connor, J. E.; Major, J. J.

    2017-12-01

    The 2011 removal of the 38 m tall Condit Dam on the White Salmon River, Washington was one of the largest dam removals to date, in terms of both dam height and sediment release. We examined the multiyear geomorphic response to this event, through 2015, including in a bedrock-confined canyon and in a less-confined, backwater-influenced pool reach near the river's mouth, to the large, rapid influx of fine reservoir sediment produced by the breach and to subsequent sediment transfer in the free-flowing White Salmon River. In the canyon reach, aggraded sediments were rapidly eroded from riffles, returning them toward pre-breach bed elevations within weeks, but pool aggradation persisted for longer. The downstream, less-confined reach transformed from a deep pool to a narrower pool-riffle channel with alternate bars; multiyear observations showed persistence of bars and of this new and distinct morphology. This downstream reach marks a rare case in post-dam removal channel response; in most dam removals, channels have rapidly reverted toward pre-removal morphology, as in the canyon reach here. Comparison of the multiyear geomorphic evolution of the White Salmon River to other recent large dam removals in the U.S. allows evaluation of the relative influences of antecedent channel morphology, post-breach hydrology, and dam removal style, as well as providing a basis for predicting responses to future dam removals.

  18. EMergy analysis perspectives of Thailand and Mekong River dam proposals

    International Nuclear Information System (INIS)

    Brown, M.T.; McClanahan, T.R.

    1996-01-01

    Methods of EMergy analysis (a scientifically based measure of wealth with units of solar emjoules (sej)) are explained and illustrated, using the economy of Thailand and two proposed dams on the Mekong River. Thailand's EMergy/$ ratio is near the world average (3.46 ·10 12 sej/$), its EMergy per capita ratio (2.98·10 15 sej/capita) is low compared to developed economies (that of the United States is 29.3·10 15 sej/capita), and its EMergy balance of payments is negative (the EMergy in exports is almost twice the EMergy in imports). The calculated net yield ratios of the proposed dams were sensitive to the treatment of sediments. The analysis yielded high net yield ratios (12.3/1 and 20.3/1) if sediments were not included, but yielded ratios of only 1.4/1 and 1.3/1 if sediments were included. If the two dams were constructed as a cascade, the combined net yield ratio was 2.5/1 (sediments included). If compared to conventional fossil fuels as a primary source of energy to the economy, the net yield ratio of the electricity generated from the two-dam cascade expressed as fossil fuels was 7.4/1

  19. Remote Sensing of Deformation of a High Concrete-Faced Rockfill Dam Using InSAR: A Study of the Shuibuya Dam, China

    Directory of Open Access Journals (Sweden)

    Wei Zhou

    2016-03-01

    Full Text Available Settlement is one of the most important deformation characteristics of high concrete faced rockfill dams (CFRDs, >100 m. High CFRDs safety would pose a great threat to the security of people’s lives and property downstream if this kind of deformation were not to be measured correctly, as traditional monitoring approaches have limitations in terms of durability, coverage, and efficiency. It has become urgent to develop new monitoring techniques to complement or replace traditional monitoring approaches for monitoring the safety and operation status of high CFRDs. This study examines the Shuibuya Dam (up to 233.5 m in height in China, which is currently the highest CFRD in the world. We used space-borne Interferometric Synthetic Aperture Radar (InSAR time series to monitor the surface deformation of the Shuibuya Dam. Twenty-one ALOS PALSAR images that span the period from 28 February 2007 to 11 March 2011 were used to map the spatial and temporal deformation of the dam. A high correlation of 0.93 between the InSAR and the in-situ monitoring results confirmed the reliability of the InSAR method; the deformation history derived from InSAR is also consistent with the in-situ settlement monitoring system. In addition, the InSAR results allow continuous investigation of dam deformation over a wide area that includes the entire dam surface as well as the surrounding area, offering a clear picture continuously of the dam deformation.

  20. Three Sisters Dam modifications and performance

    Energy Technology Data Exchange (ETDEWEB)

    Courage, L.J.R. [Monenco AGRA Inc., Calgary, AB (Canada)

    1995-12-31

    Recent modifications and maintenance carried out at the Three Sisters Dam, in the Alberta Rockies south of the town of Canmore, were described. A detailed account was given of the dam`s geological setting, its abnormally high leakage through the foundation and its sinkhole activity. Results of studies aimed at finding the cause of leakage and sinkhole occurrences were reviewed. Modifications made to the dam since 1951 were detailed, as were modifications to handle probable maximum flood levels. Three approaches for estimating failure probabilities after identification of failure modes were described. The overall conclusion was that based on constant leakage, no settlement in the dam, penstocks, or the powerhouse since construction, the Three Sisters Dam was stable. 1 ref.

  1. The changing hydrology of a dammed Amazon

    Science.gov (United States)

    Timpe, Kelsie; Kaplan, David

    2017-01-01

    Developing countries around the world are expanding hydropower to meet growing energy demand. In the Brazilian Amazon, >200 dams are planned over the next 30 years, and questions about the impacts of current and future hydropower in this globally important watershed remain unanswered. In this context, we applied a hydrologic indicator method to quantify how existing Amazon dams have altered the natural flow regime and to identify predictors of alteration. The type and magnitude of hydrologic alteration varied widely by dam, but the largest changes were to critical characteristics of the flood pulse. Impacts were largest for low-elevation, large-reservoir dams; however, small dams had enormous impacts relative to electricity production. Finally, the “cumulative” effect of multiple dams was significant but only for some aspects of the flow regime. This analysis is a first step toward the development of environmental flows plans and policies relevant to the Amazon and other megadiverse river basins. PMID:29109972

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

    Science.gov (United States)

    McDonald, Kristen; Bosshard, Peter; Brewer, Nicole

    2009-07-01

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

  3. 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

  4. Cleaning up the big muddy: A meta-synthesis of the research on the social impact of dams

    Energy Technology Data Exchange (ETDEWEB)

    Kirchherr, Julian, E-mail: julian.kirchherr@sant.ox.ac.uk; Pohlner, Huw, E-mail: huw.pohlner@oxfordalumni.org; Charles, Katrina J., E-mail: katrina.charles@ouce.ox.ac.uk

    2016-09-15

    Scholars have been exploring the social impacts of dams for over 50 years, but a lack of systematic approaches has resulted in many research gaps remaining. This paper presents the first systematic review of the literature on the social impacts of dams. For this purpose, we built a sample of 217 articles published in the past 25 years via key word searches, expert consultations and bibliography reviews. All articles were assessed against an aggregate matrix framework on the social impact of dams, which combines 27 existing frameworks. We find that existing literature is highly biased with regard to: perspective (45% negative versus 5% positive); dam size (large dams are overrepresented); spatial focus (on the resettlement area); and temporal focus (5–10 years ex-post resettlement). Additionally, there is bias in terms of whose views are included, with those of dam developers rarely examined by scholars. These gaps need to be addressed in future research to advance our knowledge on the social impact of dams to support more transparency in the trade-offs being made in dam development decisions. - Highlights: • Very first systematic review of the research on dams' social impact • Biases in the literature identified, e. g. large dams over-studied, too much focus solely on resettlement area impacts • Implications of these biases for understanding of the topic are discussed.

  5. Cleaning up the big muddy: A meta-synthesis of the research on the social impact of dams

    International Nuclear Information System (INIS)

    Kirchherr, Julian; Pohlner, Huw; Charles, Katrina J.

    2016-01-01

    Scholars have been exploring the social impacts of dams for over 50 years, but a lack of systematic approaches has resulted in many research gaps remaining. This paper presents the first systematic review of the literature on the social impacts of dams. For this purpose, we built a sample of 217 articles published in the past 25 years via key word searches, expert consultations and bibliography reviews. All articles were assessed against an aggregate matrix framework on the social impact of dams, which combines 27 existing frameworks. We find that existing literature is highly biased with regard to: perspective (45% negative versus 5% positive); dam size (large dams are overrepresented); spatial focus (on the resettlement area); and temporal focus (5–10 years ex-post resettlement). Additionally, there is bias in terms of whose views are included, with those of dam developers rarely examined by scholars. These gaps need to be addressed in future research to advance our knowledge on the social impact of dams to support more transparency in the trade-offs being made in dam development decisions. - Highlights: • Very first systematic review of the research on dams' social impact • Biases in the literature identified, e. g. large dams over-studied, too much focus solely on resettlement area impacts • Implications of these biases for understanding of the topic are discussed

  6. Impact of Geotechnical Factors on the Safety of Low Embankment Dams From the Perspective of Technical and Safety Supervision

    Directory of Open Access Journals (Sweden)

    Kasana Andrej

    2015-03-01

    Full Text Available Our research deals with a broad spectrum of problems concerning the variability of geotechnical factors and their influence on the safety of the biggest group of dam constructions in Slovakia, i.e., low earthfill dams. Its specific aim is the observation of their risk factors by using our experience and knowledge gained while working in the sector of technical and safety supervision. To achieve the aims of a research thesis, we analyzed 39 low earthfill dams. We performed observations and documented their conditions with the aim of clarifying the risk factors. After an analysis of the information materials that characterize dams and after a statistical analysis of the measurement results in situ, including measurements from technical and safety supervision databases, we performed an analysis by using mathematical modeling to evaluate the safety of the dam constructions. Out of the total number of 39 dam constructions, an analysis of the stability of the dam slopes was performed on 37 dams, and deformation problems were analyzed on 28 of the dams. Filtration problems were analyzed at 26 dams, and a complete evaluation of the intensity of filtration movements was performed on 19 of the constructions.

  7. Dinosaur tracks from the Cedar Mountain Formation (Lower Cretaceous), Arches National Park, Utah

    Science.gov (United States)

    Lockley, Martin G.; White, Diane K.; Kirkland, James I.; Santucci, Vincent L.

    2004-01-01

    The seventh and largest known dinosaur tracksite from the Cedar Mountain Formation is reported from two important stratigraphic levels in the Ruby Ranch Member within the boundaries of Arches National Park. Previous reports of sites with a few isolated tracks are of limited utility in indicating the fauna represented by track makers. The Arches site reveals evidence of several theropod morphotypes, including a possible match for the coelurosaur Nedcolbertia and an apparently didactyl Utahraptor-like dromeosaurid. Sauropod tracks indicate a wide-gauge morphotype (cf. Brontopodus). Ornithischian tracks suggest the presence of an iguandontid-like ornithopod and a large ankylosaur. Dinosaur track diversity is high in comparison with other early Cretaceous vertebrate ichnofaunas, and it correlates well with faunal lists derived from skeletal remains, thus providing a convincing census of the known fauna.

  8. Dam safety management in Victoria (Australia)

    International Nuclear Information System (INIS)

    Adem, J.

    1996-01-01

    The Victoria state government's decision to make dam owners accountable for safety and upkeep of their dams was reported. To give effect to this decision a series of guidelines have been developed which outline the required activities and skills to ensure that dams are properly managed within a framework of 'light-handed' regulation. The guidelines are also intended to ensure that dam management becomes an integral part of the business decision making process, not just a set of prescribed technical procedures. Details of the direction being taken and the proposed controls to ensure compliance with national and international standards were described. 4 refs., 2 figs

  9. Numerical modelling for stability of tailings dams

    OpenAIRE

    Auchar, Muhammad; Mattsson, Hans; Knutsson, Sven

    2013-01-01

    A tailings dam is a large embankment structure that is constructed to store the waste from the mining industry. Stability problems may occur in a tailings dam due to factors such as quick rate of raising, internal erosion and liquefaction. The failure of a tailings dam may cause loss of human life and environmental degradation. Tailings Dams must not only be stable during the time the tailings storage facility is in operation, but also long time after the mine is closed. In Sweden, the licens...

  10. Japan`s largest composition dam, aiming for harmony with nature. Chubetsu dam; Shizen tono chowa wo mezasu, Nippon ichi no fukugo dam. Chubetsu dam

    Energy Technology Data Exchange (ETDEWEB)

    Mizushima, T. [Hokkaido Development Bureau, Hokkaido Development Agency, Sapporo (Japan)

    1994-08-15

    This paper introduces Chubetsu Dam planned with a large-scale embankment having a river bed width of 600 m. Chubetsu Dam is being constructed with such objectives as flood control of Ishikari River, river flow rate maintenance, drinking water supply, irrigation water supply and power generation. The dam site is a gravel bed having a river bed width of 600 m and a maximum foundation rock thickness of 40 m, requiring evaluations as a dam foundation and discussions of water shielding methods. As a result of discussions at the Chubetsu Dam technical discussion committee, the dam type is decided to be a composition dam consisting of a gravity type concrete dam on the left river side and a central core type fill dam using a part of the gravel bed as the foundation on the right river side. A continuous underground wall system is planned to be used for shielding water in the gravel foundation. In discussing the anti-seismic properties, analyses for bank construction and water filling to derive stress and deformation conditions prior to an earthquake and a time-history response analysis to derive conditional changes during the earthquake are performed. According to the results thereof, evaluations are given on the safety by compounding the stress and the acceleration. In plans to improve the surrounding areas, an area will be provided upstream the reservoir where the water level is kept constant to serve as a bird sanctuary. 7 figs.

  11. Interpretation of self-potential data for dam seepage investigations

    Energy Technology Data Exchange (ETDEWEB)

    Corwin, R.F.; Sheffer, M.R.; Salmon, G. [BC Hydro, Burnaby, BC (Canada)

    2007-04-15

    This book represents one of a series on the subject of geophysical methods and their use in assessing seepage and internal erosion in embankment dams. This manual facilitates the interpretation of self-potential (SP) data generated by subsurface fluid flow, with an emphasis on dam seepage studies. It is intended for users with a background in geophysics or engineering having a general familiarity with both the SP and direct-current (DC) resistivity methods and their applications. It includes an extensive reference list covering all aspects of available SP interpretation techniques, including qualitative, analytical and numerical methods. Particular emphasis is placed on the use of geometric source analytical modeling methods to evaluate SP anomalies. These methods provide a simple yet efficient means of estimating the location and depth of current sources of observed SP data, which may be linked to fluid flow in the subsurface. The manual is primarily oriented toward embankment dams and earthen structures such as levees and dikes. SP methods have been used to investigate seepage through pervious zones and cracks in concrete and concrete-faced structures. The manual describes the nature of SP fields generated by both uniform and non-uniform dam seepage flow, as well as non-seepage sources of SP variations. These methods enable the study of more complex systems and require a more comprehensive analysis of a given field site. refs., tabs., figs.

  12. Rubber dam may increase the survival time of dental restorations.

    Science.gov (United States)

    Keys, William; Carson, Susan J

    2017-03-01

    Data sourcesCochrane Oral Health's Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL), Medline, Embase, LILACS, SciELO, Chinese BioMedical Literature Database, VIP, China National Knowledge Infrastructure, ClinicalTrials.gov, World Health Organization International Clinical Trials Registry Platform, OpenGrey and Sciencepaper Online databases. Handsearches in a number of journals.Study selectionRandomised controlled trials, including split-mouth studies assessing the effects of rubber dam isolation for restorative treatments in dental patients.Data extraction and synthesisTwo review authors independently screened the results of the electronic searches, extracted data and assessed the risk of bias of the included studies.ResultsFour studies involving a total of 1,270 patients were included. The studies were at high risk of bias. One trial was excluded from the analysis due to inconsistencies in the presented data. Restorations had a significantly higher survival rate in the rubber dam isolation group compared to the cotton roll isolation group at six months in participants receiving composite restorative treatment of non-carious cervical lesions (risk ratio (RR) 1.19, 95% confidence interval (CI) 1.04 to 1.37, very low-quality evidence). The rubber dam group had a lower risk of failure at two years in children undergoing proximal atraumatic restorative treatment in primary molars (hazard ratio (HR) 0.80, 95% CI 0.66 to 0.97, very low-quality evidence). One trial reported limited data showing that rubber dam usage during fissure sealing might shorten the treatment time. None of the included studies mentioned adverse effects or reported the direct cost of the treatment, or the level of patient acceptance/satisfaction. There was also no evidence evaluating the effects of rubber dam usage on the quality of the restorations.ConclusionsWe found some very low-quality evidence, from single studies, suggesting that rubber dam usage in dental direct

  13. Beaver dams and channel sediment dynamics on Odell Creek, Centennial Valley, Montana, USA

    Science.gov (United States)

    Levine, Rebekah; Meyer, Grant A.

    2014-01-01

    Beaver dams in streams are generally considered to increase bed elevation through in-channel sediment storage, thus, reintroductions of beaver are increasingly employed as a restoration tool to repair incised stream channels. Here we consider hydrologic and geomorphic characteristics of the study stream in relation to in-channel sediment storage promoted by beaver dams. We also document the persistence of sediment in the channel following breaching of dams. Nine reaches, containing 46 cross-sections, were investigated on Odell Creek at Red Rock Lakes National Wildlife Refuge, Centennial Valley, Montana. Odell Creek has a snowmelt-dominated hydrograph and peak flows between 2 and 10 m3 s- 1. Odell Creek flows down a fluvial fan with a decreasing gradient (0.018-0.004), but is confined between terraces along most of its length, and displays a mostly single-thread, variably sinuous channel. The study reaches represent the overall downstream decrease in gradient and sediment size, and include three stages of beaver damming: (1) active; (2) built and breached in the last decade; and (3) undammed. In-channel sediment characteristics and storage were investigated using pebble counts, fine-sediment depth measurements, sediment mapping and surveys of dam breaches. Upstream of dams, deposition of fine (≤ 2 mm) sediment is promoted by reduced water surface slope, shear stress and velocity, with volumes ranging from 48 to 182 m3. High flows, however, can readily transport suspended sediment over active dams. Variations in bed-sediment texture and channel morphology associated with active dams create substantial discontinuities in downstream trends and add to overall channel heterogeneity. Observations of abandoned dam sites and dam breaches revealed that most sediment stored above beaver dams is quickly evacuated following a breach. Nonetheless, dam remnants trap some sediment, promote meandering and facilitate floodplain development. Persistence of beaver dam sediment

  14. Olympic Dam - the first decade

    International Nuclear Information System (INIS)

    Newton, A.W.; Wilson, M.A.; Harris, J.

    1988-01-01

    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

  15. An engineering geological appraisal of the Chamshir dam foundation using DMR classification and kinematic analysis, southwest of Iran

    Directory of Open Access Journals (Sweden)

    Torabi Kaveh Mehdi

    2011-12-01

    Full Text Available This paper describes the results of engineering geological  investigations and rock mechanics studies carried out at the proposed Chamshir dam site. It is proposed that a 155 m high solid concrete gravity-arc dam be built across the Zuhreh River to the southeast of the city of Gachsaran in south-western Iran. The dam and its associated structures are mainly located on the Mishan formation. Analysis consisted of rock mass classification and a kinematic
    analysis of the dam foundation's rock masses. The studies were carried out in the field and the laboratory. The field studies included geological mapping, intensive discontinuity surveying, core drilling and sampling for laboratory testing. Rock mass classifications were made in line with RMR and DMR classification for the dam foundation. Dam foundation analysis regarding stability using DMR classification and kinematic analysis indicated that the left abutment's rock foundation (area 2 was unstable for planar, wedge and toppling failure modes.

  16. 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.

  17. Environmental factors and dam characteristics associated with insulin sensitivity and insulin secretion in newborn Holstein calves

    International Nuclear Information System (INIS)

    Kamal, M.M.; Van Eetvelde, M.; Bogaert, H.; Hostens, M.; Vandaele, L.; Shamsuddin, M.; Opsomer, G.

    2015-01-01

    The objective of the present retrospective cohort study was to evaluate potential associations between environmental factors and dam characteristics, including level of milk production during gestation, and insulin traits in newborn Holstein calves

  18. study and analysis of asa river hypothetical dam break using hec-ras

    African Journals Online (AJOL)

    Windows User

    outcome of the analysis showed that in the event of such failure of Asa dam, some areas which include industrial and residential .... Road Bridge (Coca Cola Axis). (iv) Stretch ..... Solutions and Case Studies, WIT Press, Southampton,. Boston ...

  19. Impacts of the Garafiri hydroelectric dam on the Konkoure estuary

    International Nuclear Information System (INIS)

    Samoura, K.; Waaub, J.P.

    2008-01-01

    This article described the environmental impacts caused by the exploitation of one or several dams in tropical coastal basins. In particular, it proposed a methodological approach for analyzing the vulnerability of ecosystems to modifications caused by the exploitation of the Garafiri hydroelectric dam in Guinea. With an installed power capacity of 75 MW, this dam has been operational since 1999 and has supplied electricity to coastal and mid Guinea since 2000. Since then, the ecosystem of the Konkoure River has undergone important changes. This study focused primarily on impacts during the dry season. Data was collected at different hydroelectric stations along the Konkoure Basin to estimate changes in water flow in the estuary. The study showed several changes, including noticeable impacts on the soil salt content. In addition, changes in vegetation were attributed to changes in soil content. The study revealed that rice production has increased 65 per cent since 2000, while salt exploitation has been completely discontinued. It was concluded that the hydraulic management of the dam can have a significant impact on the region's ecosystem which can in turn influence ecological and social economic functions. It was concluded that the vulnerability of the ecosystem can be worsened in the context of climate change. 25 refs., 9 figs

  20. Olympic Dam project: draft environmental impact statement

    International Nuclear Information System (INIS)

    1982-10-01

    The Olympic Dam deposit, South Australia, is estimated to contain at least 2,000 million tonnes of mineralized material, with an average grade of about 1.6% copper, 0.6 Kg/t of uranium oxide and 0.6 g/t of gold. The objective of the project is to extract and process the ore for the production and sale of copper, uranium oxide and the associated gold and silver. Facilities required are an underground mine, an on-site processing plant, associated facilities including a tailings retention system, a town to accommodate up to 9,000 people and other infrastructure. Chapters in the draft E.I.S. contain information on the environment, land use, aboriginal environment, geology, tailings retention system, radiation assessment, project infrastructure, social effects and economic effects

  1. Taking a new approach to dam building

    International Nuclear Information System (INIS)

    Taylor, D.

    1999-01-01

    Problems, including corruption, dogging construction of the Three Gorges dam being built in China are discussed. The article questions whether large hydro projects can ever be completed on time and within budget. It was suggested that by operating a build-operate-transfer scheme there might be greater incentives to complete on time but the vice-president of Skanska Civil Engineering was sceptical due to the risk involved. Through the Three Gorges Project, the Chinese government has learned that the relocation of thousands of people is far from easy. From a technical aspect, there may be unexpected problems in building underground. Some problems which arose in major hydro projects in India, Turkey and Lesotho were recounted. The vice-president of Skanska offered three pieces of advice and they are listed. (UK)

  2. Taking a new approach to dam building

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, D.

    1999-03-01

    Problems, including corruption, dogging construction of the Three Gorges dam being built in China are discussed. The article questions whether large hydro projects can ever be completed on time and within budget. It was suggested that by operating a build-operate-transfer scheme there might be greater incentives to complete on time but the vice-president of Skanska Civil Engineering was sceptical due to the risk involved. Through the Three Gorges Project, the Chinese government has learned that the relocation of thousands of people is far from easy. From a technical aspect, there may be unexpected problems in building underground. Some problems which arose in major hydro projects in India, Turkey and Lesotho were recounted. The vice-president of Skanska offered three pieces of advice and they are listed. (UK)

  3. Branchial arch anomalies: Recurrence, malignant degeneration and operative complications.

    Science.gov (United States)

    Al-Mufarrej, Faisal; Stoddard, David; Bite, Uldis

    2017-06-01

    Branchial arch anomalies (BAA) represent one of the commonest pediatric neck masses, but large case series are lacking with none specifically examining risk of recurrence, surgical complications, and malignancy. Retrospective study of patients with BAA at Mayo Clinic from 1/1/1976-7/29/2011. Features studied include age, gender, location, BAA type, symptoms, recurrence, preoperative management, extent of surgery, pathology as well as presence of tracts. Associations with tracts, operative complications, and recurrence were evaluated. 421 subjects underwent BAA excision during the study period at our institution. Subjects with tracts were symptomatic earlier. Four cases (mean age 60.3 years) of malignancy were identified. Among the 358 (non-remenant) BAA patients with no previous excision, 3.6% recurred at a mean of 47.1 months following surgery. Patients who underwent incision and drainage prior to BAA excision were 3.4 times more likely to recur. 2% experienced complications. Age, BAA type, preoperative imaging and extent of surgery did not affect recurrence or complication rates. Patients with history of preoperative incision and drainage should be followed closely for recurrence the first four years. Early BAA excision is not associated with higher complication rate. Extent of resection should be determined by gross margins of BAA. Malignant degeneration was not seen in children. Malignancies have been seen in older patients (over 45 years) diagnosed with BAA, and a thorough work-up is important for correct diagnosis. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Is the shortened dental arch still a satisfactory option?

    Science.gov (United States)

    Manola, M; Hussain, F; Millar, B J

    2017-07-21

    Aims Dental practitioners may hold the view that missing posterior teeth should be replaced to ensure a healthy masticatory system and satisfactory oral function. However, the shortened dental arch (SDA) concept is still in use, but after 35 years is it acceptable? This review searches the literature for the evidence and opinions regarding the suitability of the SDA as a current treatment modality.Methods Medline and PubMed databases were searched for relevant terms, all the abstracts were assessed and articles selected according to the pre-set exclusion and inclusion criteria.Results The search yielded 1,895 articles and after the assessment of the abstracts and application of the exclusion and inclusion criteria, 44 articles were selected for this review. These included 11 cohort studies, two longitudinal studies, two animal studies, three cross sectional studies, eight clinical studies and 18 case control studies. There appears to be a trend over the past three decades for more papers to be opposed to the SDA concept.Conclusion Evidence that the SDA causes pathology is lacking. Clinicians, healthcare authorities and patients have shown favourable attitudes towards the SDA and this continues, although there is an increase in studies opposing the concept and some are dissatisfied with this option. The concept remains viable particularly for the medically compromised patient or where restorations are considered unsuitable but further more specific studies are warranted.

  5. Analysis of autologous platelet-rich plasma during ascending and transverse aortic arch surgery.

    Science.gov (United States)

    Zhou, Shao-Feng; Estrera, Anthony L; Miller, Charles C; Ignacio, Craig; Panthayi, Sreelatha; Loubser, Paul; Sagun, Dean L; Sheinbaum, Roy; Safi, Hazim J

    2013-05-01

    Coagulopathy is a common complication after ascending and transverse arch aortic surgery with profound hypothermic circuit arrest (PHCA). Blood conservation strategies to reduce transfusion have been ongoing and involve multiple treatment modalities in modern cardiac surgery. The purpose of this study is to evaluate the effectiveness of autologous platelet-rich plasma (aPRP) as a blood conservation technique to reduce blood transfusion in ascending and arch aortic surgery. Between 2003 and 2009, we retrospectively reviewed 685 cases of ascending aorta and transverse arch repair using PHCA. A total of 287 patients in which aPRP was used (aPRP group) were compared with 398 patients who did have aPRP (non-aPRP group). Perioperative transfusion requirements and clinical outcomes that included early mortality, postoperative stroke, renal dysfunction, prolonged ventilation, coagulopathy, and length of postoperative intensive care unit stay were analyzed. The data were analyzed by mean and frequency for continuous variables and qualitative variables. To account for potential selection bias, 2 types of propensity analysis were performed. In both unadjusted and adjusted analysis, perioperative transfusions were fewer in the aPRP group compared with the non-aPRP group: (3.9 units fewer packed red blood cells, 4.5 units fewer fresh frozen plasma, 7.9 units fewer platelets, and 6.8 units fewer cryoprecipitate). In all analyses, postoperative morbidity (stroke, duration of mechanical ventilation, and intensive care unit stay) were significantly improved. Hospital mortality rate was not significantly decreased. The utilization of aPRP was associated with a reduction in allogeneic blood transfusions as well as a decrease in early postoperative morbidity during repairs of the ascending and transverse arch aorta using PHCA. Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  6. Precision of guided scanning procedures for full-arch digital impressions in vivo.

    Science.gov (United States)

    Zimmermann, Moritz; Koller, Christina; Rumetsch, Moritz; Ender, Andreas; Mehl, Albert

    2017-11-01

    System-specific scanning strategies have been shown to influence the accuracy of full-arch digital impressions. Special guided scanning procedures have been implemented for specific intraoral scanning systems with special regard to the digital orthodontic workflow. The aim of this study was to evaluate the precision of guided scanning procedures compared to conventional impression techniques in vivo. Two intraoral scanning systems with implemented full-arch guided scanning procedures (Cerec Omnicam Ortho; Ormco Lythos) were included along with one conventional impression technique with irreversible hydrocolloid material (alginate). Full-arch impressions were taken three times each from 5 participants (n = 15). Impressions were then compared within the test groups using a point-to-surface distance method after best-fit model matching (OraCheck). Precision was calculated using the (90-10%)/2 quantile and statistical analysis with one-way repeated measures ANOVA and post hoc Bonferroni test was performed. The conventional impression technique with alginate showed the lowest precision for full-arch impressions with 162.2 ± 71.3 µm. Both guided scanning procedures performed statistically significantly better than the conventional impression technique (p Cerec Omnicam Ortho were 74.5 ± 39.2 µm and for group Ormco Lythos 91.4 ± 48.8 µm. The in vivo precision of guided scanning procedures exceeds conventional impression techniques with the irreversible hydrocolloid material alginate. Guided scanning procedures may be highly promising for clinical applications, especially for digital orthodontic workflows.

  7. Sleepiness, occlusion, dental arch and palatal dimensions in children attention deficit hyperactivity disorder (ADHD).

    Science.gov (United States)

    Andersson, H; Sonnesen, L

    2018-04-01

    This was to compare sleepiness, occlusion, dental arch and palatal dimensions between children with attention deficit hyperactivity disorders (ADHD) and healthy children (control group). 15 children with ADHD (10 boys, 5 girls, mean age 10.98 years) and 36 healthy age matched children (21 boys, 15 girls, mean age 10.60 years) were included. Intra-oral three-dimensional scans of the teeth and palate were performed to evaluate the occlusion, dental arch and palatal dimensions. Sleepiness was evaluated from the questionnaires. The differences between the two groups were analysed by Fisher's exact test and general linear models adjusted for age and gender. The ADHD children had a significantly narrower dental arch at the gingival level of the canines (p ADHD children snored significantly more (p ADHD children had a tendency to sleep fewer hours during the night (p = 0.066) and felt inadequately rested in the morning (p = 0.051) compared to the controls. The results indicate that sleepiness and palatal width, especially the more anterior skeletal part of the palate, may be affected in children with ADHD. The results may prove valuable in the diagnosis and treatment planning of children with ADHD. Further studies are needed to investigate sleep and dental relations in children with ADHD.

  8. 3D MODELLING OF PROPHYLACTIC FOOTWEAR FOR A HIGH ARCHED FOOT

    Directory of Open Access Journals (Sweden)

    COSTEA Mariana

    2016-05-01

    Full Text Available This article approaches the methodology of designing customized footwear for high arched foot. The authors propose to reconsider the classical structure of footwear bottom components for people with high arched foot and recommend incorporating custom components, with the role of compensation or adjustment. This study continues the authors’ research, starting from a foot’s 3D shape obtained by 3D scanning, the anthropometrical and biomechanical parameters, shoe lasts’ 3D modelling and continuing with 3D footwear design. Including customized orthosis can help to stop the evolution of abnormalities, diminishes sensations of pain during walking and improves performance in various physical activities carried out during the day, walking, running, and standing. The prophylactic footwear has to meet four main requirements: to protect the foot and ankle during walking and static; to ensure the normal resistance systems (bones, muscle and joint of the foot; to prevent the installation of irreversible structural changes by reducing stress on the foot; to contribute to increased performance in conducting regular physical activity. It is presented the steps of modelling an orthosis, a virtual simulation of its cutting process, followed by the integration and development of the insole, filling and sole for a customized shoe. Delcam Crispin CAD system and its applications for orthopaedics are used to design the bottom components of prophylactic footwear for a high arched foot.

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

    Directory of Open Access Journals (Sweden)

    Bin Chen

    2015-01-01

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

  10. Biomechanics of the arch of the foot. Pre- and postoperative radiological examination

    International Nuclear Information System (INIS)

    Kristen, K.H.

    2007-01-01

    The human foot is a complex biomechanical structure. The arch of the foot is formed by the bony and articular structure of the midfoot and supported by strong ligaments and tendons. The normal arch develops in childhood. Tendon and ligament rupture and degeneration often lead to flattening of the arch. Frequent painful conditions include hallux valgus deformity and rupture of the posterior tibial tendon both leading to flat feet. Radiological examination is necessary in a standardized, full weight bearing standing position. The standing dorsoplantar view shows hallux valgus angle and intermetatarsal 1/2 angle. The side view shows Lisfranc joint instability and decrease of the talometatarsal angle. Talonavicular instability is a frequent secondary sign of spring ligament and posterior tibial tendon lesion. After failure of conservative therapy, corrective surgery with osteotomy and realignment procedure of the malpositioned bones in combination with tendon and ligament reconstruction is the state of the art procedure. In postoperative follow-up a standing X-ray of the foot is again the standard tool. Additional MRI and CT examinations help to detect bone and cartilage lesions and tendon/ligament ruptures. (orig.) [de

  11. Monitoring of Juvenile Yearling Chinook Salmon and Steelhead Survival and Passage at Bonneville Dam, Spring 2010

    Energy Technology Data Exchange (ETDEWEB)

    Ploskey, Gene R.; Faber, Derrek M.; Weiland, Mark A.; Carlson, Thomas J.

    2012-09-01

    The purpose of this study was to estimate the survival for yearling Chinook salmon and steelhead smolts during spring 2010 in a portion of the Columbia River that includes Bonneville Dam. The study estimated smolt survival from a virtual release at Bonneville Dam to a survival array 81 km downstream of Bonneville Dam. We also estimated median forebay residence time, median tailrace egress time, and spill passage efficiency (SPE), as required in the Columbia Basin Fish Accords. A single release design was used to estimate survival from Bonneville Dam to a primary array located 81 km downstream of Bonneville. The approach did not include a reference tailrace release. Releases of acoustic-tagged smolts above John Day Dam to Hood River contributed to the formation of virtual releases at a Bonneville Dam forebay entrance array and at the face of the dam. A total of 3,880 yearling Chinook salmon and 3,885 steelhead smolts were tagged and released in the investigation. The Juvenile Salmon Acoustic Telemetry System (JSATS) tag model number ATS-156dB, weighing 0.438 g in air, was used in this investigation.

  12. Descriptive characteristics of the large Italian dams

    International Nuclear Information System (INIS)

    Dello Vicario, E.; Petaccia, A.; Savanella, V.

    1999-01-01

    In the present note the characteristics of the Italian dams are examined, underlining, in a statistical view, story, geographical location, types and use of the most important works. Such a review can be useful for a more detailed analysis, both for the dams characterization and for further studies relevant to water resources utilization [it

  13. Chixoy Dam Legacies: The Struggle to Secure Reparation and the Right to Remedy in Guatemala

    OpenAIRE

    Barbara Rose Johnston

    2010-01-01

    The World Commission on Dams brought global attention to the adverse costs of large dam development, including the disproportionate displacement of indigenous peoples and ethnic minorities and the extreme impoverishment of development refugees. The WCD recommended that governments, industry and financial institutions accept responsibility for flawed development and make proper reparation, including remedial activities such as the restoration of livelihood and land compensation for relocated c...

  14. Research progress on dam-break floods

    KAUST Repository

    Wu, Jiansong; Bao, Kai; Zhang, Hui

    2011-01-01

    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.

  15. Seismic response of uplifting concrete gravity dams

    International Nuclear Information System (INIS)

    Leger, P.; Sauve, G.; Bhattacharjee, S.

    1992-01-01

    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

  16. 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.

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

    Science.gov (United States)

    Wang, Yan; Jian, Fan; Lai, Wenli; Zhao, Zhihe; Yang, Zhi; Liao, Zhengyu; Shi, Zongdao; Wu, Taixiang; Millett, Declan T; McIntyre, Grant T; Hickman, Joy

    2010-04-14

    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. To identify and assess the evidence for the effects of initial arch wires for alignment of teeth with fixed orthodontic braces in relation to alignment speed, root resorption and pain intensity. We searched the following electronic databases: the Cochrane Oral Health Group's Trials Register (30th November 2009), CENTRAL (The Cochrane Library 2009, Issue 4), MEDLINE (1950 to 30th November 2009) and EMBASE (1980 to 30th November 2009). Reference lists of articles were also searched. There was no restriction with regard to publication status or language of publication. We contacted all authors of included studies to identify additional studies. Randomised controlled trials (RCTs) of initial arch wires to align crooked teeth with fixed orthodontic braces were selected. Only studies involving patients with upper and/or lower full arch fixed orthodontic appliances were included. Two review authors were responsible for study selection, validity assessment and data extraction. All disagreements were resolved by discussion amongst the review team. Corresponding authors of included studies were contacted to obtain missing information. Seven RCTs, with 517 participants, provided data for this review. Among them, five trials investigated the speed of initial tooth alignment comparing: 0.016 inch ion-implanted A-NiTi wire versus 0.016 inch A-NiTi versus 0.0175 multistrand stainless steel wire; 0.016x0.022 inch medium force active M-NiTi wire versus 0.016x0.022 inch graded force active M-NiTi wire versus 0.0155 inch multistrand

  18. The attitudes of dental interns to the use of the rubber dam at Riyadh dental colleges

    Directory of Open Access Journals (Sweden)

    Bander Mohammed Al-Abdulwahhab

    2012-01-01

    Full Text Available Background : The rubber dam is one of the best tools for tooth isolation and infection control in the dental field. Our aim is to evaluate the attitudes toward the use of rubber dams by dental interns in Riyadh Dental Colleges (RCsDP and determine the barriers to their use. Materials and Methods: A self-administered questionnaire was designed and used for data collection. 150 questionnaires were distributed by hand to the dental interns of RCsDP over a period of two weeks. Information sought included the attitudes toward and difficulties for the use of the rubber dam, the time needed to apply the rubber dam, and the patients′ allergic history of the rubber dam. Respondents were asked to state their preference on a five point Likert type scale ranging from "strongly dislike" to "strongly like". The information and data of the completed questionnaires were statistically analyzed using Mann-Whitney U test and Friedman test. Results: Of 150 questionnaires distributed, 150 were completed and returned (response rate = 100%. Of those, 46.7% were males and 53.3% were females. In general; (43.3%, interns strongly liked the use of the rubber dam and the rest (46.7% liked the use of the rubber dam. The majority of respondents liked to use rubber dam in direct restorations more than in indirect restorations and 46.7% strongly liked to use it in posterior teeth for composite restoration. Most dental interns felt that they would strongly like to use a rubber dam for endodontic treatment whether in posterior teeth (73.3% or anterior teeth (68.7%. 66.7% of interns asked their patients if they had an allergy to latex prior to the use of the rubber dam. Child behavior (mean rank about seven is the most important reason for not using rubber dam. The time is taken to apply the rubber dam was less than five minutes in most cases. Conclusion: Most dental interns prefer to use rubber dams in the general dental field and are enthusiastic to use it in future.

  19. Super-light pearl-chain arch vaults

    DEFF Research Database (Denmark)

    Hertz, Kristian Dahl; Halding, Philip Skov

    2014-01-01

    Arch vaults are known as optimal and impressive structures, but due to their curved shapes they are extremely costly to produce in countries, where the cost of labor is high. By means of super-light pearl-chain technology arch vaults can be constructed from equal plane prefabricated elements, which...... 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...... is known from curved voluminous elements. The paper describes the first full-scale test of an arch vault made of SL-deck elements demonstrating the principle, documenting the load-bearing capacity, and solving a number of details needed in order to create vaults in practice. Considerations and plans...

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

    KAUST Repository

    Hafiz, Md Abdullah Al; Kosuru, Lakshmoji; Ramini, Abdallah; Chappanda, Karumbaiah N.; Younis, Mohammad I.

    2016-01-01

    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.

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

    KAUST Repository

    Hafiz, Md Abdullah Al

    2016-10-18

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

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

    DEFF Research Database (Denmark)

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

    2017-01-01

    -Decks: First an investigation of the system’s elastic response (maximum load of 648kN), and second a demonstration of its collapse mechanism and ultimate capacity (maximum load of 970kN). The full-scale test showed formation of plastic hinges and clear warning signs are observed at 84% of the failure load......A full-scale load test is made of two Pearl-Chain (PC) concrete arches in order to evaluate the structural response and assess the design safety. Pearl-Chain structures and Pearl-Chain arches are invented and patented at the Technical University of Denmark. PC-Arches consist of specially designed....... The ultimate, experimental load capacity is 14% higher than the calculated mainly due to the assumed static system used for the calculation. In addition to the full-scale test bridge the first ever permanent PC-Bridge is erected in Denmark in 2015....

  3. Climate change effects on design floods for dams in Sweden

    International Nuclear Information System (INIS)

    Andreasson, J.; Bergstroem, S.

    2008-01-01

    closer in time (up to 2050). This will be achieved by using regional climate scenarios from the EU-project ENSEMBLES. In the new project, the focus is broadening to also include small dams which are usually designed by using the 100-year flood. (author)

  4. A current systematic evaluation and meta-analysis of chimney graft technology in aortic arch diseases.

    Science.gov (United States)

    Ahmad, Wael; Mylonas, Spyridon; Majd, Payman; Brunkwall, Jan Sigge

    2017-11-01

    The aim of this study was to provide a review of the literature on the use of chimney graft (CG) technique in treating arterial diseases of the aortic arch and to extrapolate conclusions by summarizing the reported outcomes in a meta-analysis. An extensive electronic search was made using PubMed/MEDLINE, Science Direct Databases, and the Cochrane Library. Included in this meta-analysis were all papers published up to February 2016 on endovascular chimney technique in the arch vessels with or without adjunct extra-anatomic debranching, in any language, providing data about at least one of the essential outcomes: early and late type I endoleak, 30-day mortality rate, development of perioperative stroke, patency, and retrograde aortic dissection. Of the 478 reports yielded by the electronic search, a total of 11 publications (on 373 patients and 387 CGs) fulfilled the inclusion criteria and were included in this study. The overall estimated proportion of technical success was 91.3% (95% confidence interval [CI], 87.4%-94.0%). Of the 373 patients, 26 (7%) experienced a type Ia endoleak in the perioperative period. The overall estimated proportion of early type Ia endoleak was 9.4% (95% CI, 6.5%-13.4%). Among the 10 studies that provided data, a retrograde type A dissection was observed in 2 of 351 patients, resulting in an overall estimated proportion of 1.8% (95% CI, 0.8%-4.0%). The pooled 30-day mortality rate was 7.9% (95% CI, 4.6%-13.2%). The pooled estimation for reintervention was 10.6% (95% CI, 5%-21%); for major stroke, 2.6% (95% CI, 1.3%-5.0%); for early patency, 97.9% (95% CI, 95.8%-99%); and for late patency, 92.9% (95% CI, 87.3%-96%). Treatment of aortic diseases involving the aortic arch poses a great challenge. The CG technique has been applied as an alternative treatment option. This meta-analysis shows that endovascular repair of aortic arch disease using a CG technique in the aortic arch vessels is technically feasible and effective but not without

  5. Anthropogenic Water Uses and River Flow Regime Alterations by Dams

    Science.gov (United States)

    Ferrazzi, M.; Botter, G.

    2017-12-01

    Dams and impoundments have been designed to reconcile the systematic conflict between patterns of anthropogenic water uses and the temporal variability of river flows. Over the past seven decades, population growth and economic development led to a marked increase in the number of these water infrastructures, so that unregulated free-flowing rivers are now rare in developed countries and alterations of the hydrologic cycle at global scale have to be properly considered and characterized. Therefore, improving our understanding of the influence of dams and reservoirs on hydrologic regimes is going to play a key role in water planning and management. In this study, a physically based analytic approach is combined to extensive hydrologic data to investigate natural flow regime alterations downstream of dams in the Central-Eastern United States. These representative case studies span a wide range of different uses, including flood control, water supply and hydropower production. Our analysis reveals that the most evident effects of flood control through dams is a decrease in the intra-seasonal variability of flows, whose extent is controlled by the ratio between the storage capacity for flood control and the average incoming streamflow. Conversely, reservoirs used for water supply lead to an increase of daily streamflow variability and an enhanced inter-catchment heterogeneity. Over the last decades, the supply of fresh water required to sustain human populations has become a major concern at global scale. Accordingly, the number of reservoirs devoted to water supply increased by 50% in the US. This pattern foreshadows a possible shift in the cumulative effect of dams on river flow regimes in terms of inter-catchment homogenization and intra-annual flow variability.

  6. 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.

  7. Strengthening Masonry Arches with Lime-Based Mortar Composite

    Directory of Open Access Journals (Sweden)

    Valerio Alecci

    2017-06-01

    Full Text Available In recent decades, many strengthening interventions on masonry elements were performed by using fiber reinforced polymers (FRPs. These advanced materials proved to be effective to increase the load-carrying capacity of masonry elements and to improve their structural behavior, avoiding the most critical failure modes. Despite the advantages of this technique compared to more traditional methods, FRP systems have disadvantages related to their low resistance to high temperatures, impossibility of application on wet surfaces, low permeability, and poor compatibility with masonry supports. Therefore, composite materials made of a fiber textile embedded in an inorganic matrix were recently proposed as alternatives to FRPs for strengthening historic masonry constructions. These composite materials are easier to install, have higher resistance to high temperatures, and permit higher vapor permeability than FRPs. The inorganic matrix is frequently a cement-based mortar, and the composite materials made of a fiber textile embedded in a cement-based mortar are usually identified as FRCM (fabric reinforced cementitious matrix composites. More recently, the use of natural lime mortar as an inorganic matrix has been proposed as an alternative to cement-based mortars when historic compatibility with the substrate is strictly required, as in case of restoration of historic buildings. In this paper, the effectiveness of a fabric made of basalt fibers embedded in lime mortar matrix (Basalt-FRLM for the strengthening of masonry arches is investigated. An experimental investigation was performed on 1:2 scaled brick masonry arches strengthened at the extrados with a layer of Basalt-FRLM and tested under vertical load. The results obtained are compared with previous results obtained by the authors by testing masonry arches strengthened at their extrados with FRCM and FRP composites. This investigation highlights the effectiveness of Basalt-FRLM in increasing load

  8. Dam safety review using non-destructive methods for reinforced concrete structure

    Energy Technology Data Exchange (ETDEWEB)

    Philibert, Alain; Saint-Pierre, Francois; Turcotte, Bernard [Le Groupe S.M. International Inc., Sherbrooke, (Canada)

    2010-07-01

    Dams built at the beginning of the twentieth century include concrete structures that were put in under rehabilitation works. In some cases, the details of the structures are not well documented. In other cases, concrete damage can be hidden under new layers of undamaged material. This requires that the dam safety review in a real investigation gather the information necessary for carrying out the hydraulic and stability studies required by the Dam Safety Act. This paper presented the process of dam safety review using non-destructive methods for reinforced concrete structures. Two reinforced concrete dams built in the 1900's, the Eustic dam on the Coaticook River and the Frontenac dam on the Magog River near Sherbrooke, were evaluated by S.M. International using non-destructive methods such as sonic and ground penetrating radar methods. The studies allowed mapping of concrete damage and provided geometric information on some non visible structure elements that were part of previous reinforcement operations.

  9. Potential Impact of Planned Andean Dams on the Amazon Fluvial Ecosystem

    Science.gov (United States)

    Forsberg, B.; Melack, J. M.; Dunne, T.; Barthem, R. B.; Paiva, R. C. D.; Sorribas, M.; Silva, U. L., Jr.

    2016-12-01

    Increased energy demand has led to plans for building 151 new dams in the western Amazon, mostly in the Andes Region. Historical data and simulation scenarios were used to explore potential impacts above and below six of the largest storage dams planned for the region. These impacts included: 1) reduction in the downstream sediment supply 2) reduction in the downstream nutrient supply, 3) attenuation of the downstream flood pulse and 4) increased greenhouse gas emissions. Together, the six dams are expected to reduce the total downstream supply of sediments, total phosphorus (TP) and total nitrogen (TN) from the Andes by 66, 65 and 49%, respectively. These large reductions in sediment and nutrient supplies will have major impacts on channel geomorphology, floodplain fertility and aquatic productivity. These impacts are expected to be greatest close to the dams but could also extend to the central Amazon floodplain and delta regions. The attenuation of the downstream flood pulse following impoundment is expected to alter the survival, phenology and growth patterns of floodplain vegetation and result in lower fish yields in the downstream regions closest to the dams. Greenhouse gas emissions above and below the dams are expected to increase, contributing to significantly higher regional and global emissions for dams. Gas fired power plants are suggested as a cleaner, less impactful alternative to meeting regional energy demands.

  10. Geomorphic responses to dam removal in the United States – a two-decade perspective

    Science.gov (United States)

    Major, Jon J.; East, Amy; O'Connor, Jim E.; Grant, Gordon E.; Wilcox, Andrew C.; Magirl, Christopher S.; Collins, Matthias J.; Tullos, Desiree D.; Tsutsumi, Daizo; Laronne, Jonathan B.

    2017-01-01

    Recent decades have seen a marked increase in the number of dams removed in the United States. Investigations following a number of removals are beginning to inform how, and how fast, rivers and their ecosystems respond to released sediment. Though only a few tens of studies detail physical responses to removals, common findings have begun to emerge. They include: (1) Rivers are resilient and respond quickly to dam removals, especially when removals are sudden rather than prolonged. Rivers can swiftly evacuate large fractions of reservoir sediment (≥50% within one year), especially when sediment is coarse grained (sand and gravel). The channel downstream typically takes months to years—not decades—to achieve a degree of stability within its range of natural variability. (2) Modest streamflows (<2-year return interval flows) can erode and transport large amounts of reservoir sediment. Greater streamflows commonly are needed to access remnant reservoir sediment and transport it downstream. (3) Dam height, sediment volume, and sediment caliber strongly influence downstream response to dam removal. Removals of large dams (≥10 m tall) have had longer-lasting and more widespread downstream effects than more common removals of small dams. (4) Downstream valley morphology and position of a dam within a watershed influence the distribution of released sediment. Valley confinement, downstream channel gradient, locations and depths of channel pools, locations and geometries of extant channel bars, and locations of other reservoirs all influence the downstream fate of released sediment.

  11. Evaporation Ponds or Recharge Structures ? the Role of Check Dams in Arkavathy River Basin, India

    Science.gov (United States)

    Jeremiah, K.; Srinivasan, V.; R, A.

    2014-12-01

    "Watershed development" has been the dominant paradigm for water management in India for the last two decades. Current spending on watershed development programmes rivals spending on large dams. In practice, watershed development involves a range of soil and water conservation measures including building check dams, gully plugs, contour bunds etc. Despite their dominance in water management paradigms, relatively little empirical data exists on these structures. Importantly, even though the benefits of individual watershed structures are recognized, the cumulative impact of building hundreds of such structures on hydrologic partitioning of a watershed remains unknown. We investigated the role of check dams in two small milli-watersheds in the Arkavathy River basin in South India. We conducted a comprehensive census of all check dams in the two milli-watersheds with a total area of 26 sq km. 40 check dams (representing a density of 1.35/sq km of watershed area) were geotagged, photographed, measured and their condition was recorded. We then selected twelve check dams and monitored the water stored using capacitance sensors. We also set up Automatic Weather Stations in each watershed. Inflows, evaporation and infiltration were calculated at each site to evaluate how check dams alter hydrologic partitioning in the watershed as a whole.

  12. The Influence of Dams on Malaria Transmission in Sub-Saharan Africa.

    Science.gov (United States)

    Kibret, Solomon; Wilson, G Glenn; Ryder, Darren; Tekie, Habte; Petros, Beyene

    2017-06-01

    The construction of dams in sub-Saharan Africa is pivotal for food security and alleviating poverty in the region. However, the unintended adverse public health implications of extending the spatial distribution of water infrastructure are poorly documented and may minimize the intended benefits of securing water supplies. This paper reviews existing studies on the influence of dams on the spatial distribution of malaria parasites and vectors in sub-Saharan Africa. Common themes emerging from the literature were that dams intensified malaria transmission in semi-arid and highland areas with unstable malaria transmission but had little or no impact in areas with perennial transmission. Differences in the impacts of dams resulted from the types and characteristics of malaria vectors and their breeding habitats in different settings of sub-Saharan Africa. A higher abundance of a less anthropophilic Anopheles arabiensis than a highly efficient vector A. gambiae explains why dams did not increase malaria in stable areas. In unstable areas where transmission is limited by availability of water bodies for vector breeding, dams generally increase malaria by providing breeding habitats for prominent malaria vector species. Integrated vector control measures that include reservoir management, coupled with conventional malaria control strategies, could optimize a reduction of the risk of malaria transmission around dams in the region.

  13. The role of dams in development

    International Nuclear Information System (INIS)

    Cakmak, C.

    2001-01-01

    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

  14. Deformation Monitoring and Bathymetry Analyses in Rock-Fill Dams, a Case Study at Ataturk Dam

    Science.gov (United States)

    Kalkan, Y.; Bilgi, S.

    2014-12-01

    Turkey has 595 dams constructed between 1936 and 2013 for the purposes of irrigation, flood control, hydroelectric energy and drinking water. A major portion of the dam basins in Turkey are deprived of vegetation and have slope topography on near surrounding area. However, landscaping covered with forest around the dam basin is desirable for erosion control. In fact; the dams, have basins deprived of vegetation, fill up quickly due to sediment transport. Erosion control and forestation are important factors, reducing the sediment, to protect the water basins of the dams and increase the functioning life of the dams. The functioning life of dams is as important as the investment and construction. Nevertheless, in order to provide safety of human life living around, well planned monitoring is essential for dams. Dams are very large and critical structures and they demand the use or application of precise measuring systems. Some basic physical data are very important for assessing the safety and performance of dams. These are movement, water pressure, seepage, reservoir and tail-water elevations, local seismic activities, total pressure, stress and strain, internal concrete temperature, ambient temperature and precipitation. Monitoring is an essential component of the dam after construction and during operation and must en­able the timely detection of any behavior that could deteriorate the dam, potentially result in its shutdown or failure. Considering the time and labor consumed by long-term measurements, processing and analysis of measured data, importance of the small structural motions at regular intervals could be comprehended. This study provides some information, safety and the techniques about the deformation monitoring of the dams, dam safety and related analysis. The case study is the deformation measurements of Atatürk Dam in Turkey which is the 6th largest dam of world considering the filling volume of embankment. Brief information is given about the

  15. COMPREHENSIVE ANALYSIS ON SEEPAGE AND STRUCTURAL STABILITY OF EARTH-ROCK DAM: A CASE STUDY OF XIQUANYAN DAM IN CHINA

    Directory of Open Access Journals (Sweden)

    Qingqing GUO

    2016-07-01

    Full Text Available Earth-rock dam is commonly used in the high-dam engineering around the world. It has been widely accepted that the analysis on structural and seepage stability plays a very important role, and it is necessary to take into account while designing the earth-rock dam. In performing the analysis of structural and seepage stability, many remarkable methods are available at current stage. However, there are still some important issues remaining unsolved, including: (1 Finite element methods (FEMs is a means of solutions to analysis seepage process, but it is often a difficult task to determine the so-called seepage coefficient, because the common-used water injection test is limited in the practical work due to the high cost and complex procedure. (2 It has long been discussed that the key parameters for structural stability analysis show a significant spatial and temporal variations. It may be partly explained by the inhomogeneous dam-filling during construction work and the developing seepage process. The consequence is that one constant value of the parameter cannot represent the above variations. In this context, we solve the above issues and introduce the solution with a practical earth-rock dam project. For determining the seepage coefficient, the data from the piezo metric tube is used to calculate the potential value, based on which the seepage coefficient can be back-analysed. Then the seepage field, as well as the seepage stability are numerically analysed using the FEM-based SEEP/W program. As to the structural safety, we take into account the spatial and temporal variations of the key parameters, and incorporate the Monte-Carlo simulation method into the commonly used M-P method to calculate the frequency distribution of the obtained structural safety factor. In this way, the structural and seepage safety can be well analysed. This study is also beneficial to provide a mature method and a theoretical insight into the earth-rock dam design

  16. Oldman river dam mitigation program downstream vegetation project report, Volume II: The potential effects of an operating plan for the Oldman River dam on Riparian cottonwood forests

    Energy Technology Data Exchange (ETDEWEB)

    Mahoney, J.M.

    1993-01-01

    Extensive cottonwood (poplar) forests exist in the Oldman River valley downstream of the Oldman River dam. Studies of similar forests in nearby river valleys and elsewhere on the western prairies have found significant declines of some riparian forests following river damming. This investigation was initiated to determine the causes of cottonwood forest decline downstream from existing dams in southern Alberta; inventory the existing river valley forests in the Oldman Basin; establish study sites in the Oldman River forests to monitor changes in forest status following commissioning of the Oldman River dam, and evaluate the probable impact of proposed operating plans for the Oldman River dam and associated water control structures on downstream forests. This report summarizes the progress made in the analyses of the probable effects on the survival of the forests, including a discussion of the hydrological conditions essential for cottonwood forest regeneration and an explanation of the effects of altering these characteristics on riparian forests; the hydrological alterations expected along various river reaches in the Oldman Basin with the implementation of the proposed OD05 Oldman Dam operating plan; and preliminary analyses of the problem impacts of the OD05 operating plan on the cottonwood forests along these reaches.

  17. Apparatus for efficient sidewall containment of molten metal with horizontal alternating magnetic fields utilizing a ferromagnetic dam

    Science.gov (United States)

    Praeg, Walter F.

    1997-01-01

    An apparatus for casting sheets of metal from molten metal. The apparatus includes a containment structure having an open side, a horizontal alternating magnetic field generating structure and a ferromagnetic dam. The magnetic field and the ferromagnetic dam contain the molten metal from leaking out side portions of the open side of the containment structure.

  18. The Manantali dam. Synthesis report

    International Nuclear Information System (INIS)

    Dickmann, M.; Sieburger, Dr; Ficatier, M.; Naudet, M.; Schmidt, M.; Seve, M.

    2009-01-01

    This report proposes an ex-post assessment of the Manantali dam on the Senegal river and of the related investments in Senegal, in Mauritania and in Mali. After a presentation of the methodology adopted for this assessment study performed by several organisms, the report describes the context and the concerned sectors: project costs and funding, framework for irrigated agriculture, and framework for energy. It discusses the relevance of the project with respect to irrigated agriculture and to energy. It assesses the project performance in terms of efficiency and of viability, and with respect to environmental aspects. It presents an overview of the different direct and indirect sector-based partners which are involved in energy or rural development. The next part proposes an assessment of the global impact of the project on development as far as irrigated agriculture, the energy sector, and regional cooperation and integration are concerned. A set of lessons learned and recommendations are then formulated

  19. Proliferation of hydroelectric dams in the Andean Amazon and implications for Andes-Amazon connectivity.

    Science.gov (United States)

    Finer, Matt; Jenkins, Clinton N

    2012-01-01

    Due to rising energy demands and abundant untapped potential, hydropower projects are rapidly increasing in the Neotropics. This is especially true in the wet and rugged Andean Amazon, where regional governments are prioritizing new hydroelectric dams as the centerpiece of long-term energy plans. However, the current planning for hydropower lacks adequate regional and basin-scale assessment of potential ecological impacts. This lack of strategic planning is particularly problematic given the intimate link between the Andes and Amazonian flood plain, together one of the most species rich zones on Earth. We examined the potential ecological impacts, in terms of river connectivity and forest loss, of the planned proliferation of hydroelectric dams across all Andean tributaries of the Amazon River. Considering data on the full portfolios of existing and planned dams, along with data on roads and transmission line systems, we developed a new conceptual framework to estimate the relative impacts of all planned dams. There are plans for 151 new dams greater than 2 MW over the next 20 years, more than a 300% increase. These dams would include five of the six major Andean tributaries of the Amazon. Our ecological impact analysis classified 47% of the potential new dams as high impact and just 19% as low impact. Sixty percent of the dams would cause the first major break in connectivity between protected Andean headwaters and the lowland Amazon. More than 80% would drive deforestation due to new roads, transmission lines, or inundation. We conclude with a discussion of three major policy implications of these findings. 1) There is a critical need for further strategic regional and basin scale evaluation of dams. 2) There is an urgent need for a strategic plan to maintain Andes-Amazon connectivity. 3) Reconsideration of hydropower as a low-impact energy source in the Neotropics.

  20. Proliferation of hydroelectric dams in the Andean Amazon and implications for Andes-Amazon connectivity.

    Directory of Open Access Journals (Sweden)

    Matt Finer

    Full Text Available Due to rising energy demands and abundant untapped potential, hydropower projects are rapidly increasing in the Neotropics. This is especially true in the wet and rugged Andean Amazon, where regional governments are prioritizing new hydroelectric dams as the centerpiece of long-term energy plans. However, the current planning for hydropower lacks adequate regional and basin-scale assessment of potential ecological impacts. This lack of strategic planning is particularly problematic given the intimate link between the Andes and Amazonian flood plain, together one of the most species rich zones on Earth. We examined the potential ecological impacts, in terms of river connectivity and forest loss, of the planned proliferation of hydroelectric dams across all Andean tributaries of the Amazon River. Considering data on the full portfolios of existing and planned dams, along with data on roads and transmission line systems, we developed a new conceptual framework to estimate the relative impacts of all planned dams. There are plans for 151 new dams greater than 2 MW over the next 20 years, more than a 300% increase. These dams would include five of the six major Andean tributaries of the Amazon. Our ecological impact analysis classified 47% of the potential new dams as high impact and just 19% as low impact. Sixty percent of the dams would cause the first major break in connectivity between protected Andean headwaters and the lowland Amazon. More than 80% would drive deforestation due to new roads, transmission lines, or inundation. We conclude with a discussion of three major policy implications of these findings. 1 There is a critical need for further strategic regional and basin scale evaluation of dams. 2 There is an urgent need for a strategic plan to maintain Andes-Amazon connectivity. 3 Reconsideration of hydropower as a low-impact energy source in the Neotropics.

  1. 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.

  2. Public safety around dams : Grand River Conservation Authority

    Energy Technology Data Exchange (ETDEWEB)

    Moore, N [Grand River Conservation Authority, Cambridge, ON (Canada)

    2009-07-01

    Ontario's Grand River Conservation Authority (GRCA) is a corporate body, through which municipalities, landowners and other organizations work cooperatively to manage the watershed and outdoor recreation. This involves reducing flood damage; improving water quality; providing adequate water supply; protecting natural areas; watershed planning; and environmental education. This presentation discussed public safety issues regarding a dam in the GRCA that is 5 minutes to downtown Brantford; 5 minutes to several elementary and secondary schools; and a popular area for anglers. The city of Brantford owns the east embankment and the Brant conservation area is located on the west embankment. The safeguards included measures to involve the municipality and local police; install better signage; install better fencing; and public education. Increasing public awareness of the dangers surrounding dams was an important point of the presentation. Results included reduced trespassing and greater community awareness. figs.

  3. Arch-Axis Coefficient Optimization of Long-Span Deck-Type Concrete-Filled Steel Tubular Arch Bridge

    Science.gov (United States)

    Liu, Q. J.; Wan, S.; Liu, H. C.

    2017-11-01

    This paper is based on Nanpuxi super major bridge which is under construction and starts from Wencheng Zhejiang province to Taishun highway. A finite element model of the whole bridge is constructed using Midas Civil finite element software. The most adverse load combination in the specification is taken into consideration to determine the method of calculating the arch-axis coefficient of long-span deck-type concrete-filled steel tubular arch bridge. By doing this, this paper aims at providing references for similar engineering projects.

  4. An anthropometric analysis of facial height, arch length, and palatal rugae in the Indian and Nepalese population.

    Science.gov (United States)

    Kallianpur, Shreenivas; Desai, Ami; Kasetty, Sowmya; Sudheendra, Us; Joshi, Prathamesh

    2011-01-01

    A country such as India abounds with diverse population groups with distinct anthropometric characteristics. Among these, numerous Nepalese population groups are present in different states of India comprising one of the most common immigrant races. The aim of the study is to compare two distinct races, Indians and Nepalese on the basis of facial height proportions, arch length and palatal rugae patterns and assess their significance in racial identification. A total of 120 subjects comprising of 60 Indians and 60 Nepalese were selected, with each group including 30 males and 30 females. Facial heights were measured using sliding digital calipers, arch lengths with the help of a brass wire and rugae patterns were traced on dental casts obtained with alginate impressions. Facial height measurements did not give significant results for racial or gender identification of given races. Differences between arch length parameters were found to be significant between the two population groups. Secondary and fragmentary palatal rugae forms were found to be more common in Nepalese than Indians. The Indian and Nepalese have similar anthropometric characteristics with regard to facial height. However, arch length and palatal rugae characteristics vary between the two races.

  5. THERMAL REGIME OF MASSIVE CONCRETE DAMS WITH AIR CAVITIES IN THE SEVERE CLIMATE

    Directory of Open Access Journals (Sweden)

    Aniskin Nikolay Alekseevich

    2012-12-01

    The thermal regime of the concrete dam with an air cavity can be adjustable by simple structural elements, including a heat-insulating wall and artificial heating of cavities. The required intensity and duration of heating are to be identified. Final conclusions about the most favorable thermal regime pattern will be made upon completion of fundamental calculations of the thermal stress state of the dam to be performed in the next phase of the research.

  6. The Dams and Monitoring Systems and Case Study: Ataturk and Karakaya Dams

    Science.gov (United States)

    Kalkan, Y.; Bilgi, S.; Gülnerman, A. G.

    2017-12-01

    Dams are among the most important engineering structures used for flood controls, agricultural purposes as well as drinking and hydroelectric power. Especially after the Second World War, developments on the construction technology, increase the construction of larger capacity dams. There are more than 150.000 dams in the world and almost 1000 dams in Turkey, according to international criteria. Although dams provide benefits to humans, they possess structural risks too. To determine the performance of dams on structural safety, assessing the spatial data is very important. These are movement, water pressure, seepage, reservoir and tail-water elevations, local seismic activities, total pressure, stress and strain, internal concrete temperature, ambient temperature and precipitation. These physical data are measured and monitored by the instruments and equipment. Dams and their surroundings have to be monitored by using essential methods at periodic time intervals in order to determine the possible changes that may occur over the time. Monitoring programs typically consist of; surveillance or visual observation. These programs on dams provide information for evaluating the dam's performance related to the design intent and expected changes that could affect the safety performance of the dam. Additionally, these programs are used for investigating and evaluating the abnormal or degrading performance where any remedial action is necessary. Geodetic and non-geodetic methods are used for monitoring. Monitoring the performance of the dams is critical for producing and maintaining the safe dams. This study provides some general information on dams and their different monitoring systems by taking into account two different dams and their structural specifications with the required information. The case study in this paper depends on a comparison of the monitoring surveys on Atatürk Dam and Karakaya Dam, which are constructed on Firat River with two different structural

  7. Sustainability of dams-an evaluation approach

    Science.gov (United States)

    Petersson, E.

    2003-04-01

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

  8. Investigating leaks in dams and reservoirs

    International Nuclear Information System (INIS)

    2003-01-01

    Millions of people throughout the world depend on dams and reservoirs for electricity, water and flood protection. Dams require significant investment to build and maintain, and yet their usefulness and integrity are constantly threatened by leakage and sedimentation. Isotope hydrology techniques, combined with conventional analytical methods, are a cost-effective tool to reduce such threats. The International Atomic Energy Agency is promoting their use to protect these investments and improve management, particularly by supporting specialized teams of scientists and engineers to investigate dam leakage in African countries on request. (IAEA)

  9. Developing an integrated dam safety program

    International Nuclear Information System (INIS)

    Nielsen, N. M.; Lampa, J.

    1996-01-01

    An effort has been made to demonstrate that dam safety is an integral part of asset management which, when properly done, ensures that all objectives relating to safety and compliance, profitability, stakeholders' expectations and customer satisfaction, are achieved. The means to achieving this integration of the dam safety program and the level of effort required for each core function have been identified using the risk management approach to pinpoint vulnerabilities, and subsequently to focus priorities. The process is considered appropriate for any combination of numbers, sizes and uses of dams, and is designed to prevent exposure to unacceptable risks. 5 refs., 1 tab

  10. Predictions of total deformations in Jebba main dam by finite ...

    African Journals Online (AJOL)

    This paper examined the deformations of the Jebba Main Dam, Jebba Nigeria using the finite element method. The study also evaluated the predicted deformations and compared them with the actual deformations in the dam to identify possible causes of the observed longitudinal crack at the dam crest. The Jebba dam is a ...

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

    NARCIS (Netherlands)

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

    2015-01-01

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

  12. Evaluating safety of concrete gravity dam on weak rock: Scott Dam

    International Nuclear Information System (INIS)

    Goodman, R.E.; Ahlgren, C.S.

    2000-01-01

    Scott Dam is owned and operated by Pacific Gas and Electric Co. (PG and E) as part of the Potter Valley Project. Although it is an unimpressive concrete gravity dam [233 m (765 ft) long with maximum water surface 33.4 m (110 ft) above tail water], the dam has unusually complex and weak foundation rocks; thick condition caused design changes during construction, numerous subsequent special investigations, and several corrections and additions. A main stumbling block to clarification of the dam safety issue for Scott Dam has always been difficulty in characterizing the foundation material. This paper discusses an approach to this problem as well s how the safety of the dam was subsequently confirmed. Following a comprehensive program of research, investigations, and analysis from 1991 to 1997

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

    Directory of Open Access Journals (Sweden)

    Sanjay Orathi Patangi

    2014-01-01

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

  14. Masticatory efficiency of shortened dental arch subjects with ...

    African Journals Online (AJOL)

    Objective: The objective of this study was to compare the masticatory efficiency in subjects with shortened dental arch (SDA) before and after restoration with removable partial denture (RPD). Materials and Methods: This was a prospective study carried out on 36 consecutive patients. The subjects were asked to chew 5 g of ...

  15. 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.

  16. Knowledge and attitudes of dentists toward shortened dental arch ...

    African Journals Online (AJOL)

    Objective: The aim of this study was to assess and compare the knowledge and attitudes of dentists toward shortened dental arch (SDA) therapy in Saudi Arabia. Materials and Methods: In this cross‑sectional study, self‑designed‑structured questionnaires were distributed among specialists (SP), residents (RES), and ...

  17. Reduction and Fixation of Unstable Fractures of the Zygomatic Arch ...

    African Journals Online (AJOL)

    Radiographs in the occipitomental and submentovertex views are most ... the bone and zygomatic arch, depending on the location of the fracture points and ... lesions in the facial nerve. ... [1,2] Thus, the diagnosis of this condition is based on ...

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

    Science.gov (United States)

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

    2015-01-01

    Arch surgery remains undoubtedly among the most technically and strategically challenging endeavors in cardiovascular surgery. Surgical interventions of thoracic aneurysms involving the aortic arch require complete circulatory arrest in deep hypothermia (DHCA) or elaborate cerebral perfusion strategies with varying degrees of hypothermia to achieve satisfactory protection of the brain from ischemic insults, that is, unilateral/bilateral antegrade cerebral perfusion (ACP) and retrograde cerebral perfusion (RCP). Despite sophisticated and increasingly individualized surgical approaches for complex aortic pathologies, there remains a lack of consensus regarding the optimal method of cerebral protection and circulatory management during the time of arch exclusion. Many recent studies argue in favor of ACP with various degrees of hypothermic arrest during arch reconstruction and its advantages have been widely demonstrated. In fact ACP with more moderate degrees of hypothermia represents a paradigm shift in the cardiac surgery community and is widely adopted as an emergent strategy; however, many centers continue to report good results using other perfusion strategies. Amidst this important discussion we review currently available surgical strategies of cerebral protection management and compare the results of recent European multicenter and single-center data. PMID:26713319

  19. Masticatory Efficiency of Shortened Dental Arch Subjects with ...

    African Journals Online (AJOL)

    2017-05-16

    May 16, 2017 ... of shortened dental arch subjects with removable partial denture: A comparative ... at the post- and pre-treatment phases was statistically significant (P = 0.001). The .... after the delivery of metal-based RPD with the denture in.

  20. Study and comparison arch at framework modern materials case ...

    African Journals Online (AJOL)

    With the shaping of novel ideas and trends in architecture, the traditional use of arched structures and forms is gradually fading away and being forgotten. This is while today the advancement of technology and the emergence of a wide range of innovations as well as the utilization of superb creativity have resolved many ...

  1. Reliability and Correlation of Static and Dynamic Foot Arch Measurement in a Healthy Pediatric Population.

    Science.gov (United States)

    Scholz, Timo; Zech, Astrid; Wegscheider, Karl; Lezius, Susanne; Braumann, Klaus-Michael; Sehner, Susanne; Hollander, Karsten

    2017-09-01

    Measurement of the medial longitudinal foot arch in children is a controversial topic, as there are many different methods without a definite standard procedure. The purpose of this study was to 1) investigate intraday and interrater reliability regarding dynamic arch index and static arch height, 2) explore the correlation between both arch indices, and 3) examine the variation of the medial longitudinal arch at two different times of the day. Eighty-six children (mean ± SD age, 8.9 ± 1.9 years) participated in the study. Dynamic footprint data were captured with a pedobarographic platform. For static arch measurements, a specially constructed caliper was used to assess heel-to-toe length and dorsum height. A mixed model was established to determine reliability and variation. Reliability was found to be excellent for the static arch height index in sitting (intraday, 0.90; interrater, 0.80) and standing positions (0.88 and 0.85) and for the dynamic arch index (both 1.00). There was poor correlation between static and dynamic assessment of the medial longitudinal arch (standing dynamic arch index, r = -0.138; sitting dynamic arch index, r = -0.070). Static measurements were found to be significantly influenced by the time of day (P body mass index (P mind. For clinical purposes, static and dynamic arch data should be interpreted separately.

  2. A theoretical method for calculating the collapse load of steel circular arches

    NARCIS (Netherlands)

    Spoorenberg, R.C.; Snijder, H.H.; Hoenderkamp, J.C.D.

    2012-01-01

    Arches are frequently used in large span structures like bridges and roofs. Although these structural elements may be prone to various instability phenomena, stocky arches or slender arches with sufficient lateral bracing fail due to plastic collapse instead of in-plane buckling or out-of-plane

  3. Structural properties and out-of-plane stability of roller bent steel arches

    NARCIS (Netherlands)

    Spoorenberg, R.C.

    2011-01-01

    In contemporary architecture the use of steel arches has seen a significant increase. They are applied in buildings and large span bridges, combining structural design with architectural merits. For arches lacking lateral support (or freestanding arches) the out-of-plane structural stability

  4. Out-of-plane buckling of roller bent wide flange arches - imperfections and finite element modeling

    NARCIS (Netherlands)

    Spoorenberg, R.C.; Snijder, H.H.; Hoenderkamp, J.C.D.; Beg, D.; Chan, S.L.; Shu, G.P.

    2012-01-01

    Steel arches are used more and more in contemporary architecture, combining structural efficiency with architectural merits. If lateral supports are absent, these arches are prone to out-of-plane buckling. Arches are often made by cold bending wide flange beams at ambient temperature. This

  5. Freshwater mussel survey for the Columbia Dam removal, Paulins Kill, New Jersey

    Science.gov (United States)

    Galbraith, Heather S.; Blakeslee, Carrie J.; Cole, Jeffrey C.; Silldorff, Erik L.

    2018-06-04

    Semi-quantitative mussel surveys, conducted by the U.S. Geological Survey and the Delaware Riverkeeper Network in cooperation with The Nature Conservancy, were completed in the vicinity of the Columbia Dam, on the Paulins Kill, New Jersey, in August 2017 in order to document the mussel species composition and relative abundance prior to removal of the dam. Surveys were conducted from the Brugler Road Bridge downriver approximately 2,000 meters (m) to the Columbia Dam and downriver from the dam about 300 m to 75 m upriver from the confluence of the Paulins Kill with the Delaware River. Sixteen sections (average length=175 m) were surveyed by personnel snorkeling or SCUBA diving; 13 sections were upriver from the dam, and 3 were downriver from the dam. Mussels, as they were encountered by surveyors, were removed from the sediment, immediately identified to species, and replaced in their original collection locations. Habitat data were collected for each surveyed section. Upriver and downriver from the dam, river margins with dense vegetation were examined for mussels by personnel using snorkels in transects (approximately 25 meters) perpendicular to river flow every 50 m on both sides of the river. Only two species were found upriver from the dam, and those were present in relatively low numbers. Catch per unit effort is reported here within parentheses as the average across upriver sections in number of mussels per person hour of survey time: 42 Elliptio complanata (2.6) and 1 Pyganodon cataracta (0.1) were found upriver from the dam. No mussels were found in the dense vegetation either upriver or downriver of the dam by surveyors using snorkels. Significantly higher species richness and mussel catch per unit effort were found downriver from the dam than upriver, including 106 E. complanta (32.5), 27 Utterbackiana implicata (8.2), 1 Alasmidonta undulata (0.4), 2 Lampsilis cariosa (0.5), 6 Lampsilis radiata (2.1), 4 P. cataracta (1.1), and 1 Strophitus undulatus (0

  6. Variability of Ecosystem State in Rivers Containing Natural Dams: A Chemical Analysis

    Science.gov (United States)

    Reynolds, Z. A.

    2015-12-01

    Flooding, and the resulting economic damage to roads and property, is associated with natural dams such as beaver dams or log jams. For this reason, humans often remove natural dams; however, river reaches with natural dams provide very different ecosystem services in comparison with free-flowing river reaches. Therefore, the goal of this project is to assess the differences in ecosystem state between these different river reach types in the northeastern United States. We focused on differences in basic chemistry (e.g., dissolved oxygen, pH, temperature, and organic carbon) to assess the impact of natural dams on river ecosystem state. Study sites include rivers in the White Mountains and southeastern New Hampshire at locations with beaver dams, beaver ponds, beaver meadows, log jams, and free-flowing reaches. Dissolved oxygen, ORP, pH, temperature, and conductivity were measured in the field with a YSI Professional Plus meter. Water samples were collected for subsequent laboratory analysis of total organic carbon with a Shimadzu TOC-L. Preliminary results show that the chemistry of river water varies with feature type. Most significantly, dissolved oxygen concentrations are highest in free-flowing reaches and lowest in beaver ponds. Although beaver ponds are often associated with lower pH, due the increased concentration of organic acids, some beaver ponds can increase pH when compared to free-flowing reaches on the same river. Early results also show that water chemistry returns quickly to the chemistry typical of the free-flowing river reaches after being altered by a natural dam. Overall, natural dams create a river system that has more heterogeneity, and therefore has opportunities to provide more ecosystem functions, than a purely free-flowing river; this can increase the number of supported instream and riparian species. By increasing the understanding of how natural dams affect the chemistry of river water, river engineers can improve their decisions on how

  7. Geoelectrical Methods and Monitoring for Dam Safety Assessment, Republic of Korea

    Science.gov (United States)

    Lim, S. K.; Oldenburg, D.; Kang, S.; Song, S. H.

    2016-12-01

    Geoelectrical methods and monitoring to detect the seepage and internal erosion are essential for the safety assessment of earth dams. This work aims to develop improved methodologies to analyze the observed data and to monitor changes in seepage flow using direct current (DC) and self-potential (SP) methods. The seasonal variation of water level at dams causes a change in seepage and water saturation and hence alters the resistivity of the dam material. DC data are sensitive to water saturation and hence changes in saturation can be obtained by repeatedly measuring DC data. However, a more diagnostic parameter for safety assessment is fluid flow, and resistivity is only weakly coupled to that. Fortunately SP signals are directly related to fluid flow, and thus an SP survey has the potential to characterize fluid flow through the earth matrix. In Korea, the safety assessment of earth fill dams has been dealt by Korea Rural Community Corporation (KRC). Most of the dams are relatively old ( >50 years), hence assessing deterioration and corresponding seepage of those dams are crucial. In order to evaluate the engineering geological properties of the soil at earth dams in Korea, two boreholes in each dam were drilled to a bedrock depth that exceeds the height of the dam. A large set of field tests, including standard penetration tests (SPT) and in-situ permeability tests, were carried out along the boreholes. However, seepage paths in the dam is complex hence those limited measurements at a few points is not sufficient to delineate the zone of preferential seepage flow. For this, KRC developed permanent DC monitoring systems at a number of agricultural dams in Korea. The data were automatically collected every 6 hours. During the monitoring, the measurements of the water level at two boreholes were gathered at the same time. In this presentation we select an agricultural dam and delineate an anomalous leakage zone by inverting and interpreting time-lapse DC resistivity

  8. Comparative study on the mechanical mechanism of confined concrete supporting arches in underground engineering.

    Science.gov (United States)

    Lv, Zhijin; Qin, Qian; Jiang, Bei; Luan, Yingcheng; Yu, Hengchang

    2018-01-01

    In order to solve the supporting problem in underground engineering with high stress, square steel confined concrete (SQCC) supporting method is adopted to enhance the control on surrounding rocks, and the control effect is remarkable. The commonly used cross section shapes of confined concrete arch are square and circular. At present, designers have no consensus on which kind is more proper. To search for the answer, this paper makes an analysis on the mechanical properties of the two shapes of the cross-sections. A full-scale indoor comparative test was carried out on the commonly used straight-wall semi-circular SQCC arch and circular steel confined concrete arch (CCC arch). This test is based on self-developed full-scale test system for confined concrete arch. Our research, combining with the numerical analysis, shows: (1) SQCC arch is consistent with CCC arch in the deformation and failure mode. The largest damages parts are at the legs of both of them. (2) The SQCC arch's bearing capability is 1286.9 kN, and the CCC arch's ultimate bearing capability is 1072.4kN. Thus, the SQCC arch's bearing capability is 1.2 times that of the CCC arch. (3) The arches are subjected to combined compression and bending, bending moment is the main reason for the arch failure. The section moment of inertia of SQCC arch is 1.26 times of that of CCC arch, and the former is better than the latter in bending performance. The ultimate bearing capacity is positively correlated with the size of the moment of inertia. Based on the above research, the engineering suggestions are as follows: (1) To improve the bearing capacity of the arch, the cross-sectional shape of the chamber should be optimized and the arch bearing mode changed accordingly. (2) The key damaged positions, such as the arch leg, should be reinforced, optimizing the state of force on the arch. SQCC arches should be used for supporting in underground engineering, which is under stronger influence of the bending moment and

  9. Effect of the transpalatal arch during extraction treatment.

    Science.gov (United States)

    Zablocki, Heather L; McNamara, James A; Franchi, Lorenzo; Baccetti, Tiziano

    2008-06-01

    The transpalatal arch (TPA) can be used as an adjunct during orthodontic treatment to help control the movement of the maxillary first molars in 3 dimensions, including producing molar rotation and uprighting, maintaining transverse dimensions posteriorly during treatment, and maintaining leeway spaces during the transition of the dentition. The purpose of this retrospective cephalometric study was to test an additional function of the TPA: its ability to enhance orthodontic anchorage during extraction treatment. Records consisting of pretreatment and posttreatment cephalograms were gathered from several orthodontic practices that used an .018 x .025-in preangulated appliance. All patients were white and had 4 first premolars extracted as part of their treatment protocol. Patients were treated either with or without a TPA of the soldered Goshgarian design. Patients were excluded if headgear or any other auxiliary anchorage device beside the TPA was used during treatment. Matched samples of 30 patients were identified based on sex, age at the start of treatment, treatment duration, and cervical vertebral maturation stage. Statistical comparisons were made with nonparametric statistical tests. Analysis of the changes from pretreatment to posttreatment for the TPA and the no-TPA groups showed no statistically significant differences in any of the variables examined. The net difference for both vertical and mesial movement of the maxillary first molar in relation to the maxilla between the 2 groups was 0.4 mm, with the no-TPA group in a more downward and forward position. Although the usefulness of the TPA for the abovementioned functions is not negated, it does not provide a significant effect on either the anteroposterior or the vertical position of the maxillary first molars during extraction treatment.

  10. CREATIVITY METHODS IN TEACHING THE ARCH-DESIGN STUDIO

    Directory of Open Access Journals (Sweden)

    EIGBEONAN Andrew B.

    2013-07-01

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

  11. Energy demand, economic growth, and energy efficiency - the Bakun dam-induced sustainable energy policy revisited

    International Nuclear Information System (INIS)

    Keong, C.Y.

    2005-01-01

    In embarking on a dynamic course of economic development and industrial modernism, Malaysia sees the need to increase its electricity generation capacity through the development of a mega-dam project - the Bakun dam. Although hydroelectricity generation offers one of the benign options in accommodating the increasing energy consumption per capita in Malaysia, it is argued that the construction of Bakun's dam which involves a complete and irreversible destruction of 69,640 ha of old forest ecosystem remains a difficult and uncertain endeavour. It is further argued that apart from mega-dam technology, there are also other means to orchestrate a sustainable energy system in Malaysia. These include the implementation of demand and supply initiatives, such as the deployment of energy saving technology or influencing behavioral change towards a sustainable energy consumption pattern

  12. Technical Condition of Earthen Dams at Nizhegorodskaya HPP After 60 Years of Operation

    Energy Technology Data Exchange (ETDEWEB)

    Kuznetsov, V. S., E-mail: kuznetsovVS@vniig.ru; Ladenko, S. Yu., E-mail: ladenko@yandex.ru [B. E. Vedeneev All-Russian Research Institute of Hydraulic Engineering (JSC) (Russian Federation)

    2016-03-15

    The complex of hydraulic engineering installations includes five earthen dams. All facilities are of Class I. The diagnostic parameters of dam operation and technical condition monitored via in-situ observation for seepage mode, seepage strength, settlement, static stability, etc. generally meet design assumptions and safety criteria. Despite individual defects and signs of “aging” identified over the period of earthen dam operation, these are currently in a satisfactory and operable state. The long, 60-year operating period of the dams with no serious overhauls or emergencies has demonstrated the high reliability of the facilities, the correctness of the design and technological solutions adopted and implemented in the construction, and the high professional level of their operation in close cooperation with science.

  13. Technique and the scheme of engineering-seismometric supervision over seismic events on large dams

    Energy Technology Data Exchange (ETDEWEB)

    Karapetyan, S.; Babayan, T.; Mkrtchyan, G. [National Academy of Sciences of the Republic of Armenia (Armenia). Inst. of Geophysics and Engineering Seismology

    2004-07-01

    A network of engineering-seismometric monitoring stations have been installed at the Tavshout dam in a seismically active region of Armenia. The 37 meter high embankment dam consists of gravel-pebbles with a core of sandy clay. Recent earthquakes have presented a direct hazard for the dam and its water reservoir. In order to determine the degree of seismic hazard and prevention, it is necessary to study the interaction between the ground and the foundation of the dam. The seismometers were fixed at three points both on the foundation and the ground to obtain information on the whole route of seismic waves and to define the geology based amplification factors using empirical equations. The system of engineering-seismometric observations included a network of seismometric instruments, communications and a recording complex. 4 refs., 14 figs.

  14. Surface and subsurface soils at the Pond B dam: July 1998

    International Nuclear Information System (INIS)

    Halverson, N.V.

    1999-01-01

    Pond B, 685-13G, is an inactive reactor cooling impoundment built in 1961 on the Savannah River Site (SRS). Between 1961 and 1964, Pond B received R-Reactor cooling water discharges that were contaminated with 137 Cs, 90 Sr and plutonium. Though the pond has not been used since 1964, radionuclides from the contaminated cooling water remain in the water and in the surface sediments of the pond. The current proposal to fix and repair the Pond B dam structure includes installing a new drain system and monitoring equipment. The dam will be reinforced with additional previous material on the downstream face of the dam. The objectives of this report are to describe the sampling methodology used during the July 1998 sampling event at the downstream face of the Pond B dam and in Pond B, present the results of the sampling event, and compare, where possible, these results to related risk-based standards

  15. Dam break analysis and flood inundation map of Krisak dam for emergency action plan

    Science.gov (United States)

    Juliastuti, Setyandito, Oki

    2017-11-01

    The Indonesian Regulation which refers to the ICOLD Regulation (International Committee on Large Dam required have the Emergency Action Plan (EAP) guidelines because of the dams have potential failure. In EAP guidelines there is a management of evacuation where the determination of the inundation map based on flood modeling. The purpose of the EAP is to minimize the risk of loss of life and property in downstream which caused by dam failure. This paper will describe about develop flood modeling and inundation map in Krisak dam using numerical methods through dam break analysis (DBA) using hydraulic model Zhong Xing HY-21. The approaches of dam failure simulation are overtopping and piping. Overtopping simulation based on quadrangular, triangular and trapezium fracture. Piping simulation based on cracks of orifice. Using results of DBA, hazard classification of Krisak dam is very high. The nearest village affected dam failure is Singodutan village (distance is 1.45 kilometer from dam) with inundation depth is 1.85 meter. This result can be used by stakeholders such as emergency responders and the community at risk in formulating evacuation procedure.

  16. 33 CFR 100.1102 - Marine Events on the Colorado River, between Davis Dam (Bullhead City, Arizona) and Headgate Dam...

    Science.gov (United States)

    2010-07-01

    ... River, between Davis Dam (Bullhead City, Arizona) and Headgate Dam (Parker, Arizona). 100.1102 Section... MARINE PARADES SAFETY OF LIFE ON NAVIGABLE WATERS § 100.1102 Marine Events on the Colorado River, between Davis Dam (Bullhead City, Arizona) and Headgate Dam (Parker, Arizona). (a) General. Sponsors are...

  17. 78 FR 77397 - Flood Control Regulations, Marshall Ford Dam (Mansfield Dam and Lake Travis), Colorado River, Texas

    Science.gov (United States)

    2013-12-23

    ... Regulations, Marshall Ford Dam (Mansfield Dam and Lake Travis), Colorado River, Texas AGENCY: U.S. Army Corps... Marshall Ford Dam (Mansfield Dam and Lake Travis), Colorado River, Texas. In 1997, the Lower Colorado River... regulations to reflect changes in ownership and responsibilities of flood control management of Marshall Ford...

  18. 33 CFR 208.19 - Marshall Ford Dam and Reservoir (Mansfield Dam and Lake Travis), Colorado River, Tex.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Marshall Ford Dam and Reservoir... Marshall Ford Dam and Reservoir (Mansfield Dam and Lake Travis), Colorado River, Tex. The Secretary of the Interior, through his agent, the Lower Colorado River Authority (LCRA) shall operate the Marshall Ford Dam...

  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. Physical - Elwha River Dam Removal Study

    Data.gov (United States)

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

  1. Biological - Elwha River Dam Removal Study

    Data.gov (United States)

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

  2. Seismic risks at Elsie Lake Main Dam

    International Nuclear Information System (INIS)

    McCammon, N.R.; Momenzadeh, M.; Hawson, H.H.; Nielsen, N.M.

    1991-01-01

    The Elsie Lake dams are located on Vancouver Island in an area of high seismic risk. A safety review in 1986 indicated potential deficiencies in the earthfill main dam with respect to modern earthquake design standards. A detailed field investigation program comprising drilling and penetration tests was carried out and the results used in an assessment of seismic stability. A 0.8 m thick less dense layer in the granular shell of the dam, possibly caused by wet construction conditions, would likely liquefy in a major earthquake but sufficient residual strength would likely remain to prevent catastrophic failure. The dam shell might undergo some distortion, and an assessment was initiated to determine the requirements for reservoir drawdown following an extreme earthquake to ensure the timely lowering of the reservoir for inspection and repair. It was suggested that an adequate evacuation capability would be 25% and 50% drawdown in not more than 30 and 50 days, respectively. 9 refs., 11 figs., 1 tab

  3. Can Dams and Reservoirs Cause Earthquakes?

    Indian Academy of Sciences (India)

    induced earthquakes in that region. Figure 1. A cartoon to illus- trate the spatial relation- ships between dam, reser- ... learning experience for us graduate students. Thus, on that ... infallibility and persuasiveness as in Euclidean geometry. The.

  4. IMF-screws or arch bars as conservative treatment for mandibular condyle fractures: Quality of life aspects.

    Science.gov (United States)

    van den Bergh, B; de Mol van Otterloo, J J; van der Ploeg, T; Tuinzing, D B; Forouzanfar, T

    2015-09-01

    Arch bars as treatment for a fractured mandibular condyle are inconvenient to patients and lead to lowered quality of life (QOL). To overcome these inconveniences, IMF-screws (IMFS) to facilitate intermaxillary fixation during surgery have been developed. The purpose of the present study is to investigate and compare QOL for patients treated for a fractured mandibular condyle with either IMFS or arch bars. This research trial was conducted from 2010 to 2014 as part of an earlier prospective, multicenter, randomized clinical trial in which the use of IMFS was compared to the use of arch bars in the treatment of mandibular condylar fractures. In total, 50 patients were included: 30 (60%) male patients and 20 (40%) female patients (mean age: 31.8 years, standard deviation [SD] = 13.9 years, range = 18-64 years). A total of 24 (48%) patients were allocated in the IMFS group, and 26 (52%) patients were assigned to the arch-bars control group. Significant results were observed in the subscales social isolation, possibility to eat and vary diet, influence on sleep, and satisfaction with the given treatment, all in favour of IMFS. In conclusion, using IMFS as a method for conservative treatment of condylar fractures led to a higher QOL during the 6-week period of fracture healing. In comparison to arch bars, patients treated with IMFS experienced less social isolation, had fewer problems with eating, and express the feeling they are able to continue their normal diet. Furthermore it seems that the use of IMFS has a lower negative impact on social and financial aspects of the patient. Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  5. Olympic Dam project: assessment of the environmental impact

    International Nuclear Information System (INIS)

    1983-11-01

    The assessment report on the Environmental Impact Statement produced for the Olympic Dam project is intended to provide the South Australian Government with a comprehensive evaluation of the potential impact of the proposal and to make recommendations concerning the project to be negotiated with the Joint Venturers prior to approval of the EIS. The project involves the mining, processing and sale of products from the copper-uranium ore body at Olympic Dam on the Roxby Downs Station, South Australia. The report includes a description of the proposal, a description of the environment likely to be affected, a discussion of the potential impacts on that environment, a discussion of the adequacy of information presented in the EIS and a discussion of the acceptability of the environmental impacts. The Department has concluded that the pre-design proposal is acceptable on environmental grounds

  6. Motion planning and synchronized control of the dental arch generator of the tooth-arrangement robot.

    Science.gov (United States)

    Jiang, Jin-Gang; Zhang, Yong-De

    2013-03-01

    The traditional, manual method of reproducing the dental arch form is prone to numerous random errors caused by human factors. The purpose of this study was to investigate the automatic acquisition of the dental arch and implement the motion planning and synchronized control of the dental arch generator of the multi-manipulator tooth-arrangement robot for use in full denture manufacture. First, the mathematical model of the dental arch generator was derived. Then the kinematics and control point position of the dental arch generator of the tooth arrangement robot were calculated and motion planning of each control point was analysed. A hardware control scheme is presented, based on the industrial personal computer and control card PC6401. In order to gain single-axis, precise control of the dental arch generator, we studied the control pulse realization of high-resolution timing. Real-time, closed-loop, synchronous control was applied to the dental arch generator. Experimental control of the dental arch generator and preliminary tooth arrangement were gained by using the multi-manipulator tooth-arrangement robotic system. The dental arch generator can automatically generate a dental arch to fit a patient according to the patient's arch parameters. Repeated positioning accuracy is 0.12 mm for the slipways that drive the dental arch generator. The maximum value of single-point error is 1.83 mm, while the arc-width direction (x axis) is -33.29 mm. A novel system that generates the dental arch has been developed. The traditional method of manually determining the dental arch may soon be replaced by a robot to assist in generating a more individual dental arch. The system can be used to fabricate full dentures and bend orthodontic wires. Copyright © 2012 John Wiley & Sons, Ltd.

  7. 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...

  8. The environmental impact of large dams

    International Nuclear Information System (INIS)

    Razvan, E.

    1992-01-01

    The campaigns of conservationist groups against dams are generally based on rather emotional issues. This paper puts the situation in a more rational perspective, by analysing the various claims which tend to be put forward concerning the impacts of large dams, examining the validity of the arguments, looking at ways in which any adverse effects can be mitigated, and presenting the complexity of the problems. (author)

  9. Brief daily postpartum separations from the litter alter dam response to psychostimulants and to stress

    Directory of Open Access Journals (Sweden)

    P.P. Silveira

    2013-05-01

    Full Text Available Neonatal handling induces several behavioral and neurochemical alterations in pups, including decreased responses to stress and reduced fear in new environments. However, there are few reports in the literature concerning the behavioral effects of this neonatal intervention on the dams during the postpartum period. Therefore, the aim of the current study was to determine if brief postpartum separation from pups has a persistent impact on the dam's stress response and behavior. Litters were divided into two neonatal groups: 1 non-handled and 2 handled [10 min/day, from postnatal day (PND 1 to 10]. Weaning occurred at PND 21 when behavioral tasks started to be applied to the dams, including sweet food ingestion (PND 21, forced swimming test (PND 28, and locomotor response to a psychostimulant (PND 28. On postpartum day 40, plasma was collected at baseline for leptin assays and after 1 h of restraint for corticosterone assay. Regarding sweet food consumption, behavior during the forced swimming test or plasma leptin levels did not differ between dams briefly separated and non-separated from their pups during the postpartum period. On the other hand, both increased locomotion in response to diethylpropion and increased corticosterone secretion in response to acute stress were detected in dams briefly separated from their pups during the first 10 postnatal days. Taken together, these findings suggest that brief, repeated separations from the pups during the neonatal period persistently impact the behavior and induce signs of dopaminergic sensitization in the dam.

  10. Impacts of beaver dams on hydrologic and temperature regimes in a mountain stream

    Science.gov (United States)

    Majerova, M.; Neilson, B. T.; Schmadel, N. M.; Wheaton, J. M.; Snow, C. J.

    2015-08-01

    Beaver dams affect hydrologic processes, channel complexity, and stream temperature in part by inundating riparian areas, influencing groundwater-surface water interactions, and changing fluvial processes within stream systems. We explored the impacts of beaver dams on hydrologic and temperature regimes at different spatial and temporal scales within a mountain stream in northern Utah over a 3-year period spanning pre- and post-beaver colonization. Using continuous stream discharge, stream temperature, synoptic tracer experiments, and groundwater elevation measurements, we documented pre-beaver conditions in the first year of the study. In the second year, we captured the initial effects of three beaver dams, while the third year included the effects of ten dams. After beaver colonization, reach-scale (~ 750 m in length) discharge observations showed a shift from slightly losing to gaining. However, at the smaller sub-reach scale (ranging from 56 to 185 m in length), the discharge gains and losses increased in variability due to more complex flow pathways with beaver dams forcing overland flow, increasing surface and subsurface storage, and increasing groundwater elevations. At the reach scale, temperatures were found to increase by 0.38 °C (3.8 %), which in part is explained by a 230 % increase in mean reach residence time. At the smallest, beaver dam scale (including upstream ponded area, beaver dam structure, and immediate downstream section), there were notable increases in the thermal heterogeneity where warmer and cooler niches were created. Through the quantification of hydrologic and thermal changes at different spatial and temporal scales, we document increased variability during post-beaver colonization and highlight the need to understand the impacts of beaver dams on stream ecosystems and their potential role in stream restoration.

  11. Abandonment of the low level outlet structure at the McGregor South Dam

    Energy Technology Data Exchange (ETDEWEB)

    Mack, D.L; Murray, T.K. [Klohn-Crippen Consultants Ltd., Calgary, AB (Canada); Soutar, B.M. [Alberta Transportation, Edmonton, AB (Canada)

    2008-07-01

    The Carseland-Bow River Headworks (CBRH) is a major multi-purpose water delivery system, situated in southern Alberta. It supplies water to 87,000 hectares of agricultural land and several municipalities. The system was originally built starting in 1909. It consists of diversion works on the Bow River, 65 kilometres of canal, and the McGregor and Little Bow reservoirs. In the 1950s, the system was rehabilitated by the Prairie Farm Rehabilitation Administration (PFRA), and Travers Reservoir was added in 1954. In 1973, ownership and operation of the CBRH system was turned over to Alberta Environment. In 2001, Alberta Transportation implemented a major program to rehabilitate and upgrade the CBRH system. This program included increasing the capacity of the canals and structures, and upgrading the dams to meet current dam safety guidelines. The project involved raising the north and south dams, providing an auxiliary spillway to accommodate the probable maximum flood (PMF), and rehabilitating the existing reservoir inlet and low level outlet structures. This paper discussed the abandonment of the existing low level outlet structure located within the south dam. The paper discussed the existing dams and outlet structure as well as the south dam and outlet structure. The abandonment of the existing low level outlet structure was discussed in terms of general construction; demolition; upstream conduits and gatewell; and downstream conduit. Several illustrations and photographs of the dam and the demolition were presented. It was concluded that the in-place abandonment of the existing low level outlet structure at the McGregor South Dam provides significant advantages, including eliminating the need to construct and remove an extensive cofferdam within the reservoir. 6 refs., 2 tabs., 4 figs.

  12. Hydroacoustic Evaluation of Fish Passage through Bonneville Dam in 2004

    Energy Technology Data Exchange (ETDEWEB)

    Ploskey, Gene R.; Weiland, Mark A.; Schilt, Carl R.; Kim, Jina; Johnson, Peter N.; Hanks, Michael E.; Patterson, Deborah S.; Skalski, John R.; Hedgepeth, J

    2005-12-22

    The Portland District of the U.S. Army Corps of Engineers requested that the Pacific Northwest National Laboratory (PNNL) conduct fish-passage studies at Bonneville Dam in 2004. These studies support the Portland District's goal of maximizing fish-passage efficiency (FPE) and obtaining 95% survival for juvenile salmon passing Bonneville Dam. Major passage routes include 10 turbines and a sluiceway at Powerhouse 1 (B1), an 18-bay spillway, and eight turbines and a sluiceway at Powerhouse 2 (B2). In this report, we present results of four studies related to juvenile salmonid passage at Bonneville Dam. The studies were conducted between April 15 and July 15, 2004, encompassing most of the spring and summer migrations. Studies included evaluations of (1) Project fish passage efficiency and other major passage metrics, (2) B2 fish guidance efficiency and gap loss, (3) smolt approach and fate at the B2 Corner Collector (B2CC), and (4) B2 vertical barrier screen head differential.

  13. Advances in crosshole seismic instrumentation for dam safety monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Anderlini, G.; Anderlini, C. [BC Hydro, Burnaby, BC (Canada); Taylor, R. [RST Instruments Ltd., Coquitlam, BC (Canada)

    2009-07-01

    Since 1996, crosshole shear wave velocity measurements have been performed annually at the WAC Bennett Dam in order to monitor the performance of the dam core and integrity of the 1997 sinkhole repairs. As the testing showed to be responsive to embankment conditions and capable of detecting subtle changes, the testing program was expanded to include the development of an electrical shear wave source capable of carrying out crosshole seismic testing in Mica and Revelstoke Dams over distances of 100 metres and depths of 250 metres. This paper discussed the development and capabilities of the crosshole seismic instrumentation and presented preliminary results obtained during initial testing. Specific topics that were discussed included conventional crosshole seismic equipment; design basics; description of new crosshole seismic equipment; and automated in-situ crosshole seismic system (ACSS) system description and operation. It was concluded that the ACSS and accompanying electrical shear wave source, developed as part of the project, has advanced and improved on traditional crosshole seismic equipment. 7 refs., 9 figs.

  14. Geodetic deformation monitoring at Pendidikan Diponegoro Dam

    Science.gov (United States)

    Yuwono, Bambang Darmo; Awaluddin, Moehammad; Yusuf, M. A.; Fadillah, Rizki

    2017-07-01

    Deformation monitoring is one indicator to assess the feasibility of Dam. In order to get the correct result of the deformation, it is necessary to determine appropriate deformation monitoring network and the observation data should be analyse and evaluated carefully. Measurement and analysis of deformation requires relatively accurate data and the precision is high enough, one of the observation method that used is GPS (Global Positioning System). The research was conducted at Pendidikan Undip Dams is Dam which is located in Tembang. Diponegoro Dam was built in 2013 and a volume of 50.86 m3 of water, inundation normal width of up to 13,500 m2. The main purpose of these building is not only for drainage but also for education and micro hydro power plant etc. The main goal of this reasearch was to monitor and analyze the deformation at Pendidikan Undip Dam and to determaine whether GPS measurement could meet accuracy requirement for dam deformation measurements. Measurements were made 2 times over 2 years, 2015 and 2016 using dual frequency GPS receivers with static methods and processed by Scientific Software GAMIT 10.6

  15. A case of complete double aortic arch visualized by transthoracic echocardiography.

    Science.gov (United States)

    Saito, Naka; Kato, Shingo; Saito, Noritaka; Nakachi, Tatsuya; Fukui, Kazuki; Iwasawa, Tae; Kosuge, Masami; Kimura, Kazuo

    2017-08-01

    A case of double aortic arch that was well visualized using transthoracic echocardiography is reported. A 38-year-old man underwent transthoracic echocardiography for the evaluation of dyspnea. A suprasternal view of transthoracic echocardiography showed the ascending aorta bifurcate to left and right aortic arches, with blood flow from the ascending aorta to bilateral aortic arches. The diagnosis of right side-dominant double aortic arch was made, and the patient's symptom was conceivably related to compression of the trachea due to a vascular ring. This report indicates the potential usefulness of transthoracic echocardiography for noninvasive detection of double aortic arch in adults. © 2017, Wiley Periodicals, Inc.

  16. Hydraulics of embankment-dam breaching

    Science.gov (United States)

    Walder, J. S.; Iverson, R. M.; Logan, M.; Godt, J. W.; Solovitz, S.

    2012-12-01

    Constructed or natural earthen dams can pose hazards to downstream communities. Experiments to date on earthen-dam breaching have focused on dam geometries relevant to engineering practice. We have begun experiments with dam geometries more like those of natural dams. Water was impounded behind dams constructed at the downstream end of the USGS debris-flow flume. Dams were made of compacted, well-sorted, moist beach sand (D50=0.21 mm), 3.5 m from toe to toe, but varying in height from 0.5 to 1 m; the lower the dam, the smaller the reservoir volume and the broader the initially flat crest. Breaching was started by cutting a slot 30-40 mm wide and deep in the dam crest after filling the reservoir. Water level and pore pressure within the dam were monitored. Experiments were also recorded by an array of still- and video cameras above the flume and a submerged video camera pointed at the upstream dam face. Photogrammetric software was used to create DEMs from stereo pairs, and particle-image velocimetry was used to compute the surface-velocity field from the motion of tracers scattered on the water surface. As noted by others, breaching involves formation and migration of a knickpoint (or several). Once the knickpoint reaches the upstream dam face, it takes on an arcuate form whose continued migration we determined by measuring the onset of motion of colored markers on the dam face. The arcuate feature, which can be considered the head of the "breach channel", is nearly coincident with the transition from subcritical to supercritical flow; that is, it acts as a weir that hydraulically controls reservoir emptying. Photogenic slope failures farther downstream, although the morphologically dominant process at work, play no role at all in hydraulic control aside from rare instances in which they extend upstream so far as to perturb the weir, where the flow cross section is nearly self-similar through time. The domain downstream of the critical-flow section does influence

  17. [A new method to orthodontically correct dental occlusal plane canting: wave-shaped arch].

    Science.gov (United States)

    Zheng, X; Hu, X X; Ma, N; Chen, X H

    2017-02-18

    To introduce a technique of second order wave-shaped arch wire to orthodontically treat dental occlusal plane canting (DOPC) with left-right interactive anchorage, and to test its clinical efficacy. Among the permanent dentition malocclusion patients who showed no obvious facial asymmetry, we screened for patients who showed anterior occlusal plane canting (AOPC) after routine orthodontic examination, treatment planning, MBT fixed appliance installation and serial arch wires alignment. Each patient had been clinically appraised in frontal view by 2 orthodontists and the patient him/herself; if all 3 agreed that the AOPC was obvious, the patient was included. By this means, we included 37 patients, including 10 males and 27 females; the average age was (21.9±5.2) years. To correct AOPC, opposite direction equal curvature second order rocking-chair curve was bent on each side of 0.46 mm×0.56 mm stainless steel edgewise wire. With reference to normal occlusal plane, a curve toward the occlusal surface was made to extrude under-erupted teeth on one side while a curve toward the gingiva was made to intrude over-erupted teeth on the other side, so that the arch wire was made into a wave shape in vertical dimension. Before and after application of wave-shaped arch wire, frontal facial photographs were taken when the patient's mouth was open slightly with lips retracted to show anterior occlusal plane (AOP) clearly. An AOP was constructed by connecting the center of the slot in the medial edge of canine bracket on each side in the photograph. The angles between the bipupillary plane(BPP) and the constructed AOP were measured in ImageJ1-48v software and the angle differences before and after treatment were compared with paired Wilcoxon test in SPSS 10.0 software. The wave-shaped arch could correct AOPC effectively in 3 to 10 months time with an average of 5.5±1.7 months; the angles between AOP and BBP before treatment ranged from 2.90° to 6.12° with a median of 4.01

  18. Comparative analysis of the construction solution variants for flat arch coverings of buildings

    Directory of Open Access Journals (Sweden)

    Ibragimov Aleksandr Mayorovich

    2014-03-01

    Full Text Available Arch structures of long span buildings’ coverings are more beneficial in respect to material expenses, than beam and frame systems. Constructive schemes of roof frameworks of arch coverings are diverse, which means their operation under loading differs much. The authors offer a number of construction solutions for flat arch coverings of long span buildings. The comparative analysis of these construction solutions is presented. The operation of radial link arch is observed. The arch consists of discontinuous top chord and radial bowstring under the single load (uniformly distributed and concentrated in nods with different spans and rises. The problem of radial link arch optimization is solved in dependence with arising forces and rise. The optimal camber of arch was found. In further works the authors plan to analyze spans more than 36 meters and solve the problem in case of asymmetrical loadings.

  19. The application of data measurement before the pedicle vertebral arch fixed operation with spiral CT

    International Nuclear Information System (INIS)

    Yang Zenian; Luo Zhongyao; Chen Yong'an

    2003-01-01

    Objective: Authors carry out volume scans and 3D surface reconstruction. Then authors get the precise data of pedicle of vertebral arch, entering nail angle on horizontal direction, entering nail screw length, and the smallest horizontal diameter and entering nails' distance on pedicle of vertebral arch before the pedicle vertebral arch fixed operation. Method: Select the axial image of the widest pedicle of vertebral arch and it SSD image, measure the entering nail distance on the pedicle of vertebral arch, TSA, entering nail screw length, and the smallest horizontal diameter of the pedicle of vertebral arch. Result: The method helps to prepare the length, size and location of the nail and TSA for the pedicle of vertebral arch fixed operation, increase the operation success rate. Conclusion: This is a simple and reliable method to prepare the precise data of the nail length and size, TSA for the operation

  20. Value and limitations of chimney grafts to treat arch lesions.

    Science.gov (United States)

    Mangialardi, N; Ronchey, S; Malaj, A; Fazzini, S; Alberti, V; Ardita, V; Orrico, M; Lachat, M

    2015-08-01

    The endovascular debranching with chimney stents provides a minimally invasive alternative to open surgery with readily available devices and has extended the option of endoluminal therapy into the realm of the aortic arch. But a critical observation at the use of this technique at the aortic arch is important and necessary because of the lack of long-term results and long term patency of the stents. Our study aims to review the results of chimney grafts to treat arch lesions. A systematic health database search was performed in December 2014 according to the Prisma Guidelines. Papers were sought through a meticulous search of the MEDLINE database (National Library of Medicine, Bethesda, MA) using the Pubmed search engine. Twenty-two articles were eligible for detailed analysis and data extraction. A total of 182 patients underwent chimney techniques during TEVAR (Thoracic Endovascular Aneurysm Repair). A total of 217 chimney grafts were implanted: 36 to the IA, 1 to the RCCA, 91 to the LCCA and 89 to the LSA. The type of stent-graft used for TEVAR was described in 132 patients. The type and name of chimney graft was described in 126 patients. In 53 patients information was limited to the type. Primary technical success, defined as a complete chimney procedure was achieved in 171 patients (98%). In 8 patients it was not clearly reported. The overall stroke rate was 5.3%. The overall endoleak rate, in those papers were it was clearly reported, was 18.4% (31 patients); 23(13,6%) patients developed a type IA endoleak, 1 patient (0.6%) developed type IB endoleak and 7 patients (4.1%) developed a type II endoleak The total endovascular aortic arch debranching technique represent a good option to treat high-risk patients, because it dramatically reduces the aggressiveness of the procedure in the arch. Many concerns are still present, mainly related to durability and material interaction during time. Long-term follow-up is exceptionally important in light of the

  1. The Effects of Dams on Downstream Channel Characteristics in Pennsylvania and Maryland: Assessing the Potential Consequences of Dam Removal

    Science.gov (United States)

    Skalak, K. J.; Pizzuto, J. E.; Jenkins, P.

    2003-12-01

    The potential downstream effects of dam removal were assessed on fifteen sites of varying dam size and characteristics in Pennsylvania and Maryland. The dams ranged in size from a 30 cm high fish weir to a water supply dam 57 m high. Stream order ranged from 1 to 4. The dams are located in watersheds with varying degrees of human disturbance and urbanization. The dams are also operated differently, with significant consequences for hydraulic residence time and downstream flow variability. Most streams were alluvial, but 6 of the reaches were clearly bedrock channels. We hypothesize that the channel upstream, which is unaffected by the dam, will provide an accurate model for the channel downstream of the dam long after dam removal. Therefore, reaches upstream and downstream of the dam were compared to determine the effects of the dam as well as the condition of the stream that will ultimately develop decades after dam removal. Surprisingly, the dams had no consistent influence on channel morphology. However, the percentage of sand is significantly lower downstream than upstream: the mean % sand downstream is 11.47%, while the mean % sand upstream is 21.39%. The coarser fractions of the bed, as represented by the 84th percentile grain diameter, are unaffected by the presence of the dam. These results imply that decades after dam removal, the percentage of sand on the bed will increase, but the coarse fraction of the bed will remain relatively unchanged.

  2. Anadromous sea lampreys recolonize a Maine coastal river tributary after dam removal

    Science.gov (United States)

    Hogg, Robert; Coghlan, Stephen M.; Zydlewski, Joseph D.

    2013-01-01

    Sedgeunkedunk Stream, a third-order tributary to the Penobscot River, Maine, historically supported several anadromous fishes, including the Atlantic Salmon Salmo salar, AlewifeAlosa pseudoharengus, and Sea Lamprey Petromyzon marinus. However, two small dams constructed in the 1800s reduced or eliminated spawning runs entirely. In 2009, efforts to restore marine–freshwater connectivity in the system culminated with removal of the lowermost dam, thus providing access to an additional 4.6 km of lotic habitat. Because Sea Lampreys utilized accessible habitat prior to dam removal, they were chosen as a focal species with which to quantify recolonization. During spawning runs of 2008–2011 (before and after dam removal), individuals were marked with PIT tags and their activity was tracked with daily recapture surveys. Open-population mark–recapture models indicated a fourfold increase in the annual abundance of spawning-phase Sea Lampreys, with estimates rising from 59±4 () before dam removal (2008) to 223±18 and 242±16 after dam removal (2010 and 2011, respectively). Accompanying the marked increase in annual abundance was a greater than fourfold increase in nesting sites: the number of nests increased from 31 in 2008 to 128 and 131 in 2010 and 2011, respectively. During the initial recolonization event (i.e., in 2010), Sea Lampreys took 6 d to move past the former dam site and 9 d to expand into the furthest upstream reaches. Conversely, during the 2011 spawning run, Sea Lampreys took only 3 d to penetrate into the upstream reaches, thus suggesting a potential positive feedback in which larval recruitment into the system may have attracted adult spawners via conspecific pheromone cues. Although more research is needed to verify the migratory pheromone hypothesis, our study clearly demonstrates that small-stream dam removal in coastal river systems has the potential to enhance recovery of declining anadromous fish populations.

  3. Influence of check dams on debris-flow run-out intensity

    Directory of Open Access Journals (Sweden)

    A. Remaître

    2008-12-01

    Full Text Available Debris flows are very dangerous phenomena claiming thousands of lives and millions of Euros each year over the world. Disaster mitigation includes non-structural (hazard mapping, insurance policies, active structural (drainage systems and passive structural (check dams, stilling basins countermeasures. Since over twenty years, many efforts are devoted by the scientific and engineering communities to the design of proper devices able to capture the debris-flow volume and/or break down the energy. If considerable theoretical and numerical work has been performed on the size, the shape and structure of check dams, allowing the definition of general design criteria, it is worth noting that less research has focused on the optimal location of these dams along the debris-flow pathway.

    In this paper, a methodological framework is proposed to evaluate the influence of the number and the location of the check dams on the reduction of the debris-flow intensity (in term of flow thickness, flow velocity and volume. A debris-flow model is used to simulate the run-out of the debris flow. The model uses the Janbu force diagram to resolve the force equilibrium equations; a bingham fluid rheology is introduced and represents the resistance term. The model has been calibrated on two muddy debris-flow events that occurred in 1996 and 2003 at the Faucon watershed (South French Alps.

    Influence of the check dams on the debris-flow intensity is quantified taking into account several check dams configurations (number and location as input geometrical parameters. Results indicate that debris-flow intensity is decreasing with the distance between the source area and the first check dams. The study demonstrates that a small number of check dams located near the source area may decrease substantially the debris-flow intensity on the alluvial fans.

  4. Supra-aortic interventions for endovascular exclusion of the entire aortic arch.

    Science.gov (United States)

    Andrási, Terézia B; Grossmann, Marius; Zenker, Dieter; Danner, Bernhard C; Schöndube, Friedrich A

    2017-07-01

    Our aim was to analyze the outcomes of endovascular exclusion of the entire aortic arch (proximal landing in zone 0, distal landing in zone III or beyond, after Ishimaru) in which complete surgical debranching of the supra-aortic vessels (I), endovascular supra-aortic revascularization (chimney, fenestrated, or branched grafts) with partial surgical debranching (II), or total endovascular supra-aortic revascularization (III) was additionally performed. Publications describing endovascular repair of the aortic arch (2000-2016) were systematically searched and reviewed. From a total of 53 relevant studies including 1853 patients, only 1021 patients undergoing 35 different total aortic arch procedures were found eligible for further evaluation and included in group I, II, or III (429, 190, and 402 patients, respectively). Overall early mortality was higher in group I vs groups II and III (P = .001; 1 - β = 95.6%) but exceeded in group III (18.6%) and group II (14.0%) vs group I (8.0%; P = .044; 1 - β = 57.4%) for diseases involving zone 0. Mortality was higher in all subgroups treated for zone 0 disease compared with corresponding subgroups treated for zone I to zone III disease. The incidence of cerebral ischemic events was increased in groups I and II vs group III (7.5% and 11% vs 1.7%; P = .0001) and correlated with early mortality (R 2  = .20; P = .033). The incidence of type II endoleaks and endovascular reintervention was similar between groups and correlated with each other (R 2  = .37; P = .004). Type Ia endoleak occurred more often in groups II and III than in group I (7.1% and 12.1% vs 5.8%; P = .023) and correlated with midterm mortality (R 2  = .53; P = .005). Retrograde type A dissection was low in all groups, whereas aneurysm growth was higher in group III (2.6%, 4.2%, 10.7%; P = .002), correlating with midterm mortality (R 2  = .311; P = .009). Surgical revision slightly correlated with surgical complications (R 2  = .18; P = .044

  5. Impacts of Dams and Global Warming on Fish Biodiversity in the Indo-Burma Hotspot.

    Science.gov (United States)

    Kano, Yuichi; Dudgeon, David; Nam, So; Samejima, Hiromitsu; Watanabe, Katsutoshi; Grudpan, Chaiwut; Grudpan, Jarungjit; Magtoon, Wichan; Musikasinthorn, Prachya; Nguyen, Phuong Thanh; Praxaysonbath, Bounthob; Sato, Tomoyuki; Shibukawa, Koichi; Shimatani, Yukihiro; Suvarnaraksha, Apinun; Tanaka, Wataru; Thach, Phanara; Tran, Dac Dinh; Yamashita, Tomomi; Utsugi, Kenzo

    2016-01-01

    Both hydropower dams and global warming pose threats to freshwater fish diversity. While the extent of global warming may be reduced by a shift towards energy generation by large dams in order to reduce fossil-fuel use, such dams profoundly modify riverine habitats. Furthermore, the threats posed by dams and global warming will interact: for example, dams constrain range adjustments by fishes that might compensate for warming temperatures. Evaluation of their combined or synergistic effects is thus essential for adequate assessment of the consequences of planned water-resource developments. We made projections of the responses of 363 fish species within the Indo-Burma global biodiversity hotspot to the separate and joint impacts of dams and global warming. The hotspot encompasses the Lower Mekong Basin, which is the world's largest freshwater capture fishery. Projections for 81 dam-building scenarios revealed progressive impacts upon projected species richness, habitable area, and the proportion of threatened species as generating capacity increased. Projections from 126 global-warming scenarios included a rise in species richness, a reduction in habitable area, and an increase in the proportion of threatened species; however, there was substantial variation in the extent of these changes among warming projections. Projections from scenarios that combined the effects of dams and global warming were derived either by simply adding the two threats, or by combining them in a synergistic manner that took account of the likelihood that habitat shifts under global warming would be constrained by river fragmentation. Impacts on fish diversity under the synergistic projections were 10-20% higher than those attributable to additive scenarios, and were exacerbated as generating capacity increased-particularly if CO2 emissions remained high. The impacts of dams, especially those on river mainstreams, are likely to be greater, more predictable and more immediately pressing for

  6. Impacts of Dams and Global Warming on Fish Biodiversity in the Indo-Burma Hotspot.

    Directory of Open Access Journals (Sweden)

    Yuichi Kano

    Full Text Available Both hydropower dams and global warming pose threats to freshwater fish diversity. While the extent of global warming may be reduced by a shift towards energy generation by large dams in order to reduce fossil-fuel use, such dams profoundly modify riverine habitats. Furthermore, the threats posed by dams and global warming will interact: for example, dams constrain range adjustments by fishes that might compensate for warming temperatures. Evaluation of their combined or synergistic effects is thus essential for adequate assessment of the consequences of planned water-resource developments. We made projections of the responses of 363 fish species within the Indo-Burma global biodiversity hotspot to the separate and joint impacts of dams and global warming. The hotspot encompasses the Lower Mekong Basin, which is the world's largest freshwater capture fishery. Projections for 81 dam-building scenarios revealed progressive impacts upon projected species richness, habitable area, and the proportion of threatened species as generating capacity increased. Projections from 126 global-warming scenarios included a rise in species richness, a reduction in habitable area, and an increase in the proportion of threatened species; however, there was substantial variation in the extent of these changes among warming projections. Projections from scenarios that combined the effects of dams and global warming were derived either by simply adding the two threats, or by combining them in a synergistic manner that took account of the likelihood that habitat shifts under global warming would be constrained by river fragmentation. Impacts on fish diversity under the synergistic projections were 10-20% higher than those attributable to additive scenarios, and were exacerbated as generating capacity increased-particularly if CO2 emissions remained high. The impacts of dams, especially those on river mainstreams, are likely to be greater, more predictable and more

  7. Investigation of changes to the operation of Keenleyside Dam to reduce supersaturation of dissolved gases downstream

    International Nuclear Information System (INIS)

    Nunn, J.O.H.; Fidler, L.E.; Northcott, P.

    1993-01-01

    Keenlyside Dam is located on the Columbia River in southeast British Columbia. It impounds Arrow Lakes Reservoir, which has a live storage of 8.8 billion m 3 . The dam is used for flood control and to increase power generation in the USA. Recent field measurements have shown that the current operation of the dam often creates high levels of total gas pressure (TGP) downstream of the dam, with supersaturation levels occasionally reaching as high as 140%. It appeared that these increased levels were associated with the use of the spillway. High levels of dissolved gases may have adverse effects on aquatic life. Therefore, a comprehensive study was initiated to investigate ways of reducing TGP levels. The discharge facilities at the dam are described, along with the effects of dissolved gas supersaturation on fish. Current studies include measurement of field TGP levels, development of a model to predict TGP levels for different modes of operation of the discharge facilities, assessing the effects of TGP on different fish species at different life stages, field testing of the discharge facilities, and assessment of long-term impacts of various operating alternatives on the dam structures and equipment. Preliminary results indicate that the north low-level ports of the spillway increase the TGP level significantly less than the other two components of the discharge facilities. Current operating practice therefore maximizes use of the north ports within current operating limits. 9 refs., 4 figs

  8. Effect of longitudinal profile on the seismic anaysis of concrete gravity dams

    International Nuclear Information System (INIS)

    El-Nady, A.; Ghobarah, A.; Aziz, T.S.

    1992-01-01

    The traditional three-dimensional analysis of concrete gravity dams is expensive and very difficult. An alternate approach is to divide the dam into substructures. Each monolith is considered as a substructure and its degrees of freedom are reduced to those on the contact surfaces with the adjacent monoliths as well as a few Ritz vectors. Using this procedure high accuracy was achieved using a reasonable number of degrees of freedom. The analysis is carried out in the frequency domain to account for the frequency dependent parameters in the reservoir substructure. The procedure was tested and compared to typical three-dimensional analysis and was found to give high accuracy. A simplified cross section of gravity dams with different longitudinal profiles was studied using the substructuring procedure as well as a typical two-dimensional analysis. The results obtained show a significant variation in dynamic properties of the dam from that calculated assuming two-dimensional analysis. Furthermore, the response of the dam varies significantly when including the effect of longitudinal profile of the structure. It is concluded that the two-dimensional representation of the structure may substantially overestimate the response of the dam, depending on its longitudinal profile, especially when keyed joints are used in the construction. 13 refs., 5 figs., 4 tabs

  9. Research on Real-Time Supervisory System for Compaction Quality in Face Rockfill Dam Engineering

    Directory of Open Access Journals (Sweden)

    Shengxiang Huang

    2018-01-01

    Full Text Available Compaction quality control in filling construction is of great significance to the stability and durability of the face rockfill dam. The conventional method of quality control mainly relies on manual process control and inspection for a limited number of test holes, which cannot meet the high requirements of modern mechanized construction and schedule anymore, with increasing of scale of face rockfill dams. There is an urgent need to propose a new quality control method of face rockfill dams during the entire compaction process. In this paper, a supervisory system based on GNSS (Global Navigation Satellite System technology, wireless data communication technology, Internet of things technology, and computer technology is developed to supervise the real-time roller compaction parameters of the working surface including rolling track, rolling times, rolling speed, thickness, and smoothness. The system obtains continuous and high-precision spatial position information of roller compaction machines through GNSS technology and then calculates the roller compaction parameter information. The compaction quality control for the face rockfill dam is achieved through the supervision of roller compaction parameters. The feasibility and robustness of the developed supervisory system are validated by a case study in the face rockfill dam of Shuibuya project in China. The practice shows that the system provides a new and effective method of process control for the construction quality of the roller compaction in dam engineering and realizes real-time, precision, and automatic supervising of roller compaction parameters and ensures better construction quality.

  10. Application of genetic programming in shape optimization of concrete gravity dams by metaheuristics

    Directory of Open Access Journals (Sweden)

    Abdolhossein Baghlani

    2014-12-01

    Full Text Available A gravity dam maintains its stability against the external loads by its massive size. Hence, minimization of the weight of the dam can remarkably reduce the construction costs. In this paper, a procedure for finding optimal shape of concrete gravity dams with a computationally efficient approach is introduced. Genetic programming (GP in conjunction with metaheuristics is used for this purpose. As a case study, shape optimization of the Bluestone dam is presented. Pseudo-dynamic analysis is carried out on a total number of 322 models in order to establish a database of the results. This database is then used to find appropriate relations based on GP for design criteria of the dam. This procedure eliminates the necessity of the time-consuming process of structural analyses in evolutionary optimization methods. The method is hybridized with three different metaheuristics, including particle swarm optimization, firefly algorithm (FA, and teaching–learning-based optimization, and a comparison is made. The results show that although all algorithms are very suitable, FA is slightly superior to other two algorithms in finding a lighter structure in less number of iterations. The proposed method reduces the weight of dam up to 14.6% with very low computational effort.

  11. Design, construction and performance of the Oldman River Dam grout curtain

    Energy Technology Data Exchange (ETDEWEB)

    Hartmaier, H.; Davachi, M. [Acres International Ltd., Calgary, AB (Canada); Dharmawardene, W. [Alberta Environment, Edmonton, AB (Canada); Sinclair, B. [Acres International Ltd., Niagara Falls, ON (Canada)

    2002-07-01

    The 76 m high Oldman River Dam was constructed between 1986 and 1991 near Pincher Creek, Alberta to provide flow regulation and on-stream storage of water for multi-purpose use and irrigation services as well as hydroelectric development. The dam's main structure includes an earth- and rockfill dam, a low earthfill dyke 1500 m long, twin diversion/low level outlet tunnels, a gated spillways structure, and 2 drainage tunnels. A 1.3 km long, three-line grout curtain up to 100 m deep extends below the foundation of the dam and spillway. The grout curtain was built in undeformed Paleocene sedimentary rocks affected by stress relief due to river valley erosion. 80 per cent of the grout consumption was from bedrock structural features. Piezometers, slope indicators and flow measurement weirs were installed in the dam and abutment areas both during and after construction to monitor the performance of the grout curtain. Instrument readings indicate that the grout curtain is successfully preventing the transmission of reservoir pressures to the foundation beneath the downstream shell of the dam. The piezometric pressures downstream of the grout curtain are the same as they were in the foundation before impounding. A small amount of seepage has appeared at the end of the grout curtain at the eastern end of the abutment of the spillway but it is not considered to be significant. 3 refs., 4 figs.

  12. Dam construction as an engineering solution for water supply problem : environmental thrusts

    Energy Technology Data Exchange (ETDEWEB)

    Hosseini, A.H. [Alberta Univ., Edmonton, AB (Canada). Dept. of Civil and Environmental Engineering

    2004-09-01

    Water supply management and the potential impacts associated with engineering practices in water supply systems were examined. Global aspects of increasing water demand were presented and compared with populations, urbanization and water demand. Engineering practices in waterworks developments such as dam construction, river intakes, infiltration galleries, wells, boreholes and adits were also discussed. Construction of large dams and the problems associated with damming the rivers were studied as large dams generally have substantial impacts on rivers, watersheds and aquatic ecosystems, leading to the irreversible loss of species populations and ecosystems. These problems include negative impacts on the terrestrial ecosystem, greenhouse gas emissions from reservoirs due to decaying vegetation and carbon inflows from the catchment, changes in flow regimes, trapping of sediments and nutrients behind a dam, blocking migration of aquatic organisms, as well as negative impacts on flood plain ecosystems and fisheries. In addition, a case study, on the environmental impacts associated with damming in Three Gorges Valley in China was presented. 9 refs., 8 figs.

  13. Investigation of seasonal thermal flow in a real dam reservoir using 3-D numerical modeling

    Directory of Open Access Journals (Sweden)

    Üneş Fatih

    2015-03-01

    Full Text Available Investigations indicate that correct estimation of seasonal thermal stratification in a dam reservoir is very important for the dam reservoir water quality modeling and water management problems. The main aim of this study is to develop a hydrodynamics model of an actual dam reservoir in three dimensions for simulating a real dam reservoir flows for different seasons. The model is developed using nonlinear and unsteady continuity, momentum, energy and k-ε turbulence model equations. In order to include the Coriolis force effect on the flow in a dam reservoir, Coriolis force parameter is also added the model equations. Those equations are constructed using actual dimensions, shape, boundary and initial conditions of the dam and reservoir. Temperature profiles and flow visualizations are used to evaluate flow conditions in the reservoir. Reservoir flow’s process and parameters are determined all over the reservoir. The mathematical model developed is capable of simulating the flow and thermal characteristics of the reservoir system for seasonal heat exchanges. Model simulations results obtained are compared with field measurements obtained from gauging stations for flows in different seasons. The results show a good agreement with the field measurements.

  14. Investigation of quality of storage dam in Ilam, identifying of pollutant resources and pollutants attitude

    Directory of Open Access Journals (Sweden)

    Moayed Avazpour

    2013-12-01

    Full Text Available Water quality of dam storage is highly affected by upstream environment and basin. Regarding other conducted studies, there exist various reasons such as some studies and general monitoring of dams which cause some main problems including salinity, chemical and microbial pollution eutrophication, and sedimentation. Chame-Gerdalan storage dam in Ilam Province is one of the storages which have many environmental issues because of discharge upstream rural wastewaters, animal excreta, agricultural drainage, and leachate. The aim of this study is to signify the quality of Ilam’s storage dam and also to recognize the pollutant resources and to analyze the pollutants’ behavior at different times and sites in order to determine dam properties for agricultural and domestic usages. Regarding the importance of the topic, the present study (in the year 2012 is based on the collected information of water quality of the basin, recognition of pollutant resources and measurement of qualitative parameters such as temperature, TDS, EC, BOD5, COD, nitrogen, phosphor, and pH in seven periods of time (from May to November. The results show that the total increase in the concentration of all variables along the basin are over double, in particular, Nitrat, Sulfat, BOD, and COD. After analyzing data with some water quality indexes, we analyzed water quality of the storage and some strategies were applied in order to control the effect decrease in the dam storage which, a management program was presented to improve water quality.

  15. Status and Habitat Requirements of White Sturgeon Populations in the Columbia River Downstream from McNary Dam, 1989-1990 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Nigro, Anthony A. (Oregon Department of Fish and Wildlife, Portland, OR)

    1990-09-01

    We report on our progress from April 1989 through March 1990 on determining the status and habitat requirements of white sturgeon populations in the Columbia River downstream from McNary Dam. The study is a cooperative effort by the Oregon Department of Fish and Wildlife (ODFW), Washington Department of Fisheries (WDF), US Fish and Wildlife Service (FWS) and National Marine Fisheries Service (NMFS). Study objectives addressed by each agency are to describe the life history and population dynamics of subadults and adults between Bonneville and McNary dams and evaluate the need and identify potential methods for protecting, mitigating and enhancing populations downstream from McNary Dam, to describe the white sturgeon recreational fishery between Bonneville and McNary dams, describe reproductive and early life history characteristics downstream from Bonneville Dam and describe life history and population dynamics of subadults and adults downstream from Bonneville Dam, to describe reproduction and early life history characteristics, define habitat requirements for spawning and rearing and quantify extent of habitat available between Bonneville and McNary dams, and to describe reproduction and early life history characteristics, define habitat requirements for spawning and rearing and quantify extent of habitat available downstream from Bonneville Dam. Our approach is to work concurrently downstream and upstream from Bonneville Dam. Upstream from Bonneville Dam we began work in the Dalles Reservoir in 1987 and expanded efforts to Bonneville Reservoir in 1988 and John Day Reservoir in 1989. Highlights from this work is also included. 47 refs., 33 figs., 66 tabs.

  16. the effect of age of dam on weaning mass for ftve dam breed types

    African Journals Online (AJOL)

    SUMMARY: The effect of age of dam on adjusted 210 day calf weaning mass was estimated by the Least Squares method for 5 dam types on 2 farms. ... the later maturing breeds would have a low level of productivity because these cows would be eliminated in their potentially prime .... time at 28 (2A) or 3l (28) months old.

  17. The interplay of activists and dam developers : the case of Myanmar’s mega-dams

    NARCIS (Netherlands)

    Kirchherr, Julian|info:eu-repo/dai/nl/411261487; J. Charles, Katrina; Walton, Matthew J.

    2017-01-01

    Scholars investigating activism against large dam developments in Asia usually focus on those campaigning, but not on those the campaigns are aimed at–the dam developers. Yet the developers’ perspective is crucial to comprehensively understand the dynamics of social and environmental activism in

  18. Dam that social networking: connecting South Africa's major dams to social media

    CSIR Research Space (South Africa)

    Butgereit, L

    2011-10-01

    Full Text Available where four major South African dams are connected to Twitter and Facebook (and other social media such as MXit and Google Chat) in a mechanism which would be easy to replicate for additional dams or rivers. Data is supplied by the South African...

  19. Status and habitat requirements of the white sturgeon populations in the Columbia River downstream from McNary Dam

    International Nuclear Information System (INIS)

    Nigro, A.A.

    1991-09-01

    We report on our progress from April 1990 through March 1991 on determining the status and habitat requirements of white sturgeon populations in the Columbia River downstream from McNary Dam. The study is a cooperative effort by the Oregon Department of Fish and Wildlife (ODFW), Washington Department of Fisheries (WDF), US Fish and Wildlife Service (FWS) and National Marine Fisheries Service (NMFS). Study objectives addressed by each agency are to describe the life history and population dynamics of subadults and adults between Bonneville and McNary dams and evaluate the need and identify potential methods for protecting, mitigating and enhancing populations downstream from NcNary Dam; to describe the white sturgeon recreational fishery between Bonneville and McNary dams, describe reproductive and early life history characteristics downstream from Bonneville Dam and describe life history and population dynamics of subadults and adults downstream from Bonneville Dam; to describe reproduction and early life history characteristics, define habitat requirements for spawning and rearing and quantify extent of habitat available between Bonneville and McNary dams; and to describe reproduction and early life history characteristics, define habitat requirements for spawning and rearing and quantify extent of habitat available downstream from Bonneville Dam. Our approach is to work concurrently downstream and upstream from Bonneville Dam. Upstream from Bonneville Dam we began work in the Dalles Reservoir in 1987 and expanded efforts to Bonneville Reservoir in 1988 and John Day Reservoir in 1989. Highlights of results of this work in the Dalles, Bonneville and John Day reservoirs are included in the four pages included in this report

  20. Lower Granite dam smolt monitoring program: annual report, 2000; ANNUAL

    International Nuclear Information System (INIS)

    Morrill, Charles

    2000-01-01

    The 2000 fish collection season at Lower Granite was characterized by lower than average spring flows and spill, low levels of debris, cool water temperatures, increased unclipped yearling and subyearling chinook smolts, and 8,300,546 smolts collected and transported compared to 5,882,872 in 1999. With the continued release of unclipped supplementation chinook and steelhead above Lower Granite Dam, we can no longer accurately distinguish wild chinook, steelhead, and sockeye/kokanee in the sample. Although some table titles in this report still show ''wild'' column headings, the numbers in these columns for 1999 and 2000 include wild and unclipped hatchery origin smolts. The increases over previous years reflect the increased supplementation. A total of 8,300,546 juvenile salmonids were collected at Lower Granite Dam. Of these, 187,862 fish were bypassed back to the river and 7,950,648 were transported to release sites below Bonneville Dam, 7,778,853 by barge and 171,795 by truck. A total of 151,344 salmonids were examined in daily samples. Nine research projects conducted by four agencies impacted a total of 1,361,006 smolts (16.4% of the total collection)

  1. Determination of metals in water from Billings dam, Sao Paulo

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Talita; Sarkis, Jorge E.S.; Ulrich, Joao C.; Yamaguishi, Renata Bazante, E-mail: taoliveira@ipen.br, E-mail: jesarkis@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Menezes, Luciana Carvalho Bezerra de; Castro, Paula Maria Genova de; Monteiro Junior, Adalberto Jose; Maruyama, Lidia Sumile, E-mail: lcbm@usp.br [Instituto de Pesca, (IP/SAA-SP), Sao Paulo, SP (Brazil). Secretaria da Agricultura e Abastecimento do Estado de Sao Paulo

    2013-07-01

    The Billings reservoir, located in Sao Paulo, Brazil, is used for several purposes such as: water supply, electric generation, fishing and leisure. Although considered an area of environmental protection, in recent years the dam has suffered diverse environmental aggressions including the release of toxic metals. This study presents a recent evaluation of metal contents along the Dam. Samples were collected every three months during the period of winter 2009 to summer 2010. Samples were collected in thirteen points along of the dam, as follows: Rio dos Porcos (Point 1), Summit Control (Point 2), Ilha do Bigua (Point 3), Casa Caida (Point 4), Barragem (Point 5), Foz de Taquacetuba (Point 6), Braco Borore (Point 7), Foz de Borore (Point 8), Alvarenga (Point 9), Pedreira (Point 10), Borore's Margin (Point 11), Capivari I's Margin (Point 12) and Capivari II's Margin (Point 13). The determination of Al, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb and Zn was performed by using high resolution inductively coupled plasma mass spectrometer (HR-ICPMS). The methodology has been validated using certified reference material Riverine Water Reference Material for Trace Metals provided by National Research Council Canada (NRCC). The sampling points located in the Pedreira, Borore's Margin, Alvarenga, Barragem Taquacetuba, Casa Caida e Ilha do Bigua presented the highest concentrations. The level for Fe, Cu and Ni were higher than the ones reported in the literature and above the limit set by CONAMA 2914/201. (author)

  2. Cordova Lake dam hydroelectric generating station case study

    International Nuclear Information System (INIS)

    Kerr, D.; Huxley, J.

    1993-01-01

    The Ontario Ministry of Natural Resources released a Crown owned site to the private water power industry as part of the small hydro site release program initiated by the Ontario Government in the mid 1980's. The Cordova Lake Dam Hydroelectric Generating Station, built on this site, has been in operation since the first week of October, 1992. Since that time, the plant has been operating with less than 1 % down time and has generated over 2,400 MWh of electricity. Algonquin Power Systems is responsible for the management and operations of the plant which includes full time monitoring from the company's Mississauga office and a part time employee at Cordova Lake. Cordova Lake Dam is located on the Crowe River at the outlet of Cordova Lake, approximately 125 kilometers east of Toronto, Ontario. The total cost of the Cordova Lake Dam project was $1.6 million. Algonquin Power contributed 20% equity to the project. Algonquin Power was also responsible for all engineering and geotechnical work and for completing the construction and equipment contracts. 1 tab., 2 figs

  3. Dam Removals and River Restoration in International Perspective

    Directory of Open Access Journals (Sweden)

    Chris S. Sneddon

    2017-10-01

    Full Text Available In the Anthropocene era, questions over institutions, economics, culture and politics are central to the promotion of water-society relations that enhance biophysical resilience and democratic modes of environmental governance. The removal of dams and weirs from river systems may well signal an important shift in how human actors value and utilize rivers. Yet the removal of water infrastructure is often lengthy, institutionally complex, and characterized by social conflict. This Special Issue draws insights from case studies of recent efforts in North America and Europe to restore river systems through dam and weir removal. These cases include both instances where removal has come to fruition in conjunction with efforts to rehabilitate aquatic systems and instances where removal has been stymied by a constellation of institutional, political and cultural factors. Drawing from diverse theoretical frames and methodological approaches, the authors present novel ways to conceptualize water-society relations using the lens of dam removal and river restoration, as well as crucial reminders of the multiple biophysical and social dimensions of restoration initiatives for water resource practitioners interested in the rehabilitation of socioecological systems.

  4. Determination of metals in water from Billings dam, Sao Paulo

    International Nuclear Information System (INIS)

    Oliveira, Talita; Sarkis, Jorge E.S.; Ulrich, Joao C.; Yamaguishi, Renata Bazante; Menezes, Luciana Carvalho Bezerra de; Castro, Paula Maria Genova de; Monteiro Junior, Adalberto Jose; Maruyama, Lidia Sumile

    2013-01-01

    The Billings reservoir, located in Sao Paulo, Brazil, is used for several purposes such as: water supply, electric generation, fishing and leisure. Although considered an area of environmental protection, in recent years the dam has suffered diverse environmental aggressions including the release of toxic metals. This study presents a recent evaluation of metal contents along the Dam. Samples were collected every three months during the period of winter 2009 to summer 2010. Samples were collected in thirteen points along of the dam, as follows: Rio dos Porcos (Point 1), Summit Control (Point 2), Ilha do Bigua (Point 3), Casa Caida (Point 4), Barragem (Point 5), Foz de Taquacetuba (Point 6), Braco Borore (Point 7), Foz de Borore (Point 8), Alvarenga (Point 9), Pedreira (Point 10), Borore's Margin (Point 11), Capivari I's Margin (Point 12) and Capivari II's Margin (Point 13). The determination of Al, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb and Zn was performed by using high resolution inductively coupled plasma mass spectrometer (HR-ICPMS). The methodology has been validated using certified reference material Riverine Water Reference Material for Trace Metals provided by National Research Council Canada (NRCC). The sampling points located in the Pedreira, Borore's Margin, Alvarenga, Barragem Taquacetuba, Casa Caida e Ilha do Bigua presented the highest concentrations. The level for Fe, Cu and Ni were higher than the ones reported in the literature and above the limit set by CONAMA 2914/201. (author)

  5. Mine tailings dams: Characteristics, failure, environmental impacts, and remediation

    International Nuclear Information System (INIS)

    Kossoff, D.; Dubbin, W.E.; Alfredsson, M.; Edwards, S.J.; Macklin, M.G.; Hudson-Edwards, K.A.

    2014-01-01

    On a global scale demand for the products of the extractive industries is ever increasing. Extraction of the targeted resource results in the concurrent production of a significant volume of waste material, including tailings, which are mixtures of crushed rock and processing fluids from mills, washeries or concentrators that remain after the extraction of economic metals, minerals, mineral fuels or coal. The volume of tailings is normally far in excess of the liberated resource, and the tailings often contain potentially hazardous contaminants. A priority for a reasonable and responsible mining organization must be to proactively isolate the tailings so as to forestall them from entering groundwaters, rivers, lakes and the wind. There is ample evidence that, should such tailings enter these environments they may contaminate food chains and drinking water. Furthermore, the tailings undergo physical and chemical change after they have been deposited. The chemical changes are most often a function of exposure to atmospheric oxidation and tends to make previously, perhaps safely held contaminants mobile and available. If the tailings are stored under water, contact with the atmosphere is substantially reduced, thereby forestalling oxygen-mediated chemical change. It is therefore accepted practice for tailings to be stored in isolated impoundments under water and behind dams. However, these dams frequently fail, releasing enormous quantities of tailings into river catchments. These accidents pose a serious threat to animal and human health and are of concern for extractive industries and the wider community. It is therefore of importance to understand the nature of the material held within these dams, what best safety practice is for these structures and, should the worst happen, what adverse effects such accidents might have on the wider environment and how these might be mitigated. This paper reviews these factors, covering the characteristics, types and magnitudes

  6. Modeling the capacity of riverscapes to support beaver dams

    Science.gov (United States)

    Macfarlane, William W.; Wheaton, Joseph M.; Bouwes, Nicolaas; Jensen, Martha L.; Gilbert, Jordan T.; Hough-Snee, Nate; Shivik, John A.

    2017-01-01

    The construction of beaver dams facilitates a suite of hydrologic, hydraulic, geomorphic, and ecological feedbacks that increase stream complexity and channel-floodplain connectivity that benefit aquatic and terrestrial biota. Depending on where beaver build dams within a drainage network, they impact lateral and longitudinal connectivity by introducing roughness elements that fundamentally change the timing, delivery, and storage of water, sediment, nutrients, and organic matter. While the local effects of beaver dams on streams are well understood, broader coverage network models that predict where beaver dams can be built and highlight their impacts on connectivity across diverse drainage networks are lacking. Here we present a capacity model to assess the limits of riverscapes to support dam-building activities by beaver across physiographically diverse landscapes. We estimated dam capacity with freely and nationally-available inputs to evaluate seven lines of evidence: (1) reliable water source, (2) riparian vegetation conducive to foraging and dam building, (3) vegetation within 100 m of edge of stream to support expansion of dam complexes and maintain large colonies, (4) likelihood that channel-spanning dams could be built during low flows, (5) the likelihood that a beaver dam is likely to withstand typical floods, (6) a suitable stream gradient that is neither too low to limit dam density nor too high to preclude the building or persistence of dams, and (7) a suitable river that is not too large to restrict dam building or persistence. Fuzzy inference systems were used to combine these controlling factors in a framework that explicitly also accounts for model uncertainty. The model was run for 40,561 km of streams in Utah, USA, and portions of surrounding states, predicting an overall network capacity of 356,294 dams at an average capacity of 8.8 dams/km. We validated model performance using 2852 observed dams across 1947 km of streams. The model showed

  7. The Total Risk Analysis of Large Dams under Flood Hazards

    Directory of Open Access Journals (Sweden)

    Yu Chen

    2018-02-01

    Full Text Available Dams and reservoirs are useful systems in water conservancy projects; however, they also pose a high-risk potential for large downstream areas. Flood, as the driving force of dam overtopping, is the main cause of dam failure. Dam floods and their risks are of interest to researchers and managers. In hydraulic engineering, there is a growing tendency to evaluate dam flood risk based on statistical and probabilistic methods that are unsuitable for the situations with rare historical data or low flood probability, so a more reasonable dam flood risk analysis method with fewer application restrictions is needed. Therefore, different from previous studies, this study develops a flood risk analysis method for large dams based on the concept of total risk factor (TRF used initially in dam seismic risk analysis. The proposed method is not affected by the adequacy of historical data or the low probability of flood and is capable of analyzing the dam structure influence, the flood vulnerability of the dam site, and downstream risk as well as estimating the TRF of each dam and assigning corresponding risk classes to each dam. Application to large dams in the Dadu River Basin, Southwestern China, demonstrates that the proposed method provides quick risk estimation and comparison, which can help local management officials perform more detailed dam safety evaluations for useful risk management information.

  8. Hydrogeophysical investigations at Hidden Dam, Raymond, California

    Science.gov (United States)

    Minsley, Burke J.; Burton, Bethany L.; Ikard, Scott; Powers, Michael H.

    2011-01-01

    Self-potential and direct current resistivity surveys are carried out at the Hidden Dam site in Raymond, California to assess present-day seepage patterns and better understand the hydrogeologic mechanisms that likely influence seepage. Numerical modeling is utilized in conjunction with the geophysical measurements to predict variably-saturated flow through typical two-dimensional dam cross-sections as a function of reservoir elevation. Several different flow scenarios are investigated based on the known hydrogeology, as well as information about typical subsurface structures gained from the resistivity survey. The flow models are also used to simulate the bulk electrical resistivity in the subsurface under varying saturation conditions, as well as the self-potential response using petrophysical relationships and electrokinetic coupling equations.The self-potential survey consists of 512 measurements on the downstream area of the dam, and corroborates known seepage areas on the northwest side of the dam. Two direct-current resistivity profiles, each approximately 2,500 ft (762 m) long, indicate a broad sediment channel under the northwest side of the dam, which may be a significant seepage pathway through the foundation. A focusing of seepage in low-topography areas downstream of the dam is confirmed from the numerical flow simulations, which is also consistent with past observations. Little evidence of seepage is identified from the self-potential data on the southeast side of the dam, also consistent with historical records, though one possible area of focused seepage is identified near the outlet works. Integration of the geophysical surveys, numerical modeling, and observation well data provides a framework for better understanding seepage at the site through a combined hydrogeophysical approach.

  9. Cooperative action of multiple cis-acting elements is required for N-myc expression in branchial arches: specific contribution of GATA3.

    Science.gov (United States)

    Potvin, Eric; Beuret, Laurent; Cadrin-Girard, Jean-François; Carter, Marcelle; Roy, Sophie; Tremblay, Michel; Charron, Jean

    2010-11-01

    The precise expression of the N-myc proto-oncogene is essential for normal mammalian development, whereas altered N-myc gene regulation is known to be a determinant factor in tumor formation. Using transgenic mouse embryos, we show that N-myc sequences from kb -8.7 to kb +7.2 are sufficient to reproduce the N-myc embryonic expression profile in developing branchial arches and limb buds. These sequences encompass several regulatory elements dispersed throughout the N-myc locus, including an upstream limb bud enhancer, a downstream somite enhancer, a branchial arch enhancer in the second intron, and a negative regulatory element in the first intron. N-myc expression in the limb buds is under the dominant control of the limb bud enhancer. The expression in the branchial arches necessitates the interplay of three regulatory domains. The branchial arch enhancer cooperates with the somite enhancer region to prevent an inhibitory activity contained in the first intron. The characterization of the branchial arch enhancer has revealed a specific role of the transcription factor GATA3 in the regulation of N-myc expression. Together, these data demonstrate that correct N-myc developmental expression is achieved via cooperation of multiple positive and negative regulatory elements.

  10. Oxygenation impairment after total arch replacement with a stented elephant trunk for type-A dissection.

    Science.gov (United States)

    Shen, Yuwen; Liu, Chuanzhen; Fang, Changcun; Xi, Jie; Wu, Shuming; Pang, Xinyan; Song, Guangmin

    2018-06-01

    To study the risk factors of oxygenation impairment in patients with type-A acute aortic dissection who underwent total arch replacement with a stented elephant trunk. In this study, 169 consecutive patients were enrolled who were diagnosed with type-A acute aortic dissection and underwent a total arch replacement procedure at the Qilu Hospital of Shandong University between January 2015 and February 2017. Postoperative oxygenation impairment was defined as arterial oxygen partial pressure/inspired oxygen fraction ≤ 200 with positive end expiratory pressure ≥ 5 cm H 2 O that occurred within 72 hours of surgery. Perioperative clinical characteristics of all patients were collected and univariable analyses were performed. Risk factors associated with oxygenation impairment identified by univariable analyses were included in the multivariable regression analysis. The incidence of postoperative oxygenation impairment was 48.5%. Postoperative oxygenation impairment was associated with prolonged mechanical ventilation time, intensive care unit stay, and hospital stay. Multivariable regression analysis demonstrated that body mass index (odds ratio [OR], 1.204; 95% confidence interval [CI], 1.065-1.361; P = .003), preoperative oxygenation impairment (OR, 9.768; 95% CI, 4.159-22.941; P impairment. Postoperative oxygenation impairment is a common complication of surgery for type-A acute aortic dissection. Body mass index, preoperative oxygenation impairment, preoperative homocysteine, circulatory arrest time, and plasma transfusion were independent risk factors for oxygenation impairment after a total arch replacement procedure. Copyright © 2018 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

  11. Analysis of Static Load Test of a Masonry Arch Bridge

    Science.gov (United States)

    Shi, Jing-xian; Fang, Tian-tian; Luo, Sheng

    2018-03-01

    In order to know whether the carrying capacity of the masonry arch bridge built in the 1980s on the shipping channel entering and coming out of the factory of a cement company can meet the current requirements of Level II Load of highway, through the equivalent load distribution of the test vehicle according to the current design specifications, this paper conducted the load test, evaluated the bearing capacity of the in-service stone arch bridge, and made theoretical analysis combined with Midas Civil. The results showed that under the most unfavorable load conditions the measured strain and deflection of the test sections were less than the calculated values, the bridge was in the elastic stage under the design load; the structural strength and stiffness of the bridge had a certain degree of prosperity, and under the in the current conditions of Level II load of highway, the bridge structure was in a safe state.

  12. Arched needle technique for inferior alveolar mandibular nerve block.

    Science.gov (United States)

    Chakranarayan, Ashish; Mukherjee, B

    2013-03-01

    One of the most commonly used local anesthetic techniques in dentistry is the Fischer's technique for the inferior alveolar nerve block. Incidentally this technique also suffers the maximum failure rate of approximately 35-45%. We studied a method of inferior alveolar nerve block by injecting a local anesthetic solution into the pterygomandibular space by arching and changing the approach angle of the conventional technique and estimated its efficacy. The needle after the initial insertion is arched and inserted in a manner that it approaches the medial surface of the ramus at an angle almost perpendicular to it. The technique was applied to 100 patients for mandibular molar extraction and the anesthetic effects were assessed. A success rate of 98% was obtained.

  13. Public safety around dams : proposed technical bulletins

    Energy Technology Data Exchange (ETDEWEB)

    Raska, C [BC Hydro, Burnaby, BC (Canada); Rowat, L [Ontario Power Generation Inc., Niagara Falls, ON (Canada)

    2009-07-01

    This presentation provided an introduction to the Canadian Dam Association (CDA) public safety guideline and proposed technical bulletins for exterior danger and warning signs; waterway booms and buoys; and audible and visual alerts for water conveyance structures. The presentation outlined the hierarchy of documents for principles, guidelines and technical bulletins. Effective signage includes signs in which the text is sized according to the viewing distance; the message identifies the hazard and the actions to take; and the wording is understood by the public. The criteria for effective booms and buoys were discussed in terms of visibility of booms; types of buoys to use; distance between booms floats; design issues for headpond application versus tailrace application; angling to facilitate self-rescue; and distance from structure. Proposed criteria for audible and visual alerts were also discussed. The audible and visual danger signal should have a designated signal reception area where people can recognize and react to the signal. If a visual signalling device is used, it should be red to indicate danger. Maintenance and inspection tests should be performed regularly on audible and visual signalling devices. 1 ref., 2 figs.

  14. Horizon Dam design, construction, and quality management

    Energy Technology Data Exchange (ETDEWEB)

    Patrick, B. [EBA Engineering Consultants Ltd., Nanaimo, BC (Canada); Sisson, R. [Canadian Natural Resources Ltd., Fort McMurray, AB (Canada)

    2010-07-01

    This paper discussed the design and construction of the Tar River Diversion Dam and the quality management system (QMS) used during construction. The project was unusual in that the company constructed the project using its own workforce, without contractors, under challenging schedule and site conditions. The topography, geology and geotechnical aspects of the site were discussed along with the embankment design, seepage control measures and construction execution. The QMS was designed to fit the needs of the unique construction execution strategy and meet safety, reliability, performance, and operation requirements, comply with all regulations and approval conditions, and identify and communicate risk to the appropriate entity. Specifications and construction procedures had to be modified to accommodate equipment operators trained with the skills and techniques of mine operations, not those associated with conventional civil construction projects. Foundation movement identified during construction required mid-build design changes, construction rescheduling, and additional deformation analyses to determine long-term stability. The QMS allowed changes in the understanding of site conditions to be quickly addressed and risks to be identified and cost-effectively mitigated. Design consultants were used to modify designs and appropriately identify and mitigate risks. The approach to embankment construction was successful because the QMS included processes for change management, issue resolution, and risk-benefit assessment, and because experienced personnel had a regular presence on the construction site and worked collaboratively. The effective QMS was deemed to be integral to the success of the construction project. 1 tab., 7 figs.

  15. Quantifying the role of Trojan dams in the between-herd spread of bovine viral diarrhoea virus (BVDv) in Ireland.

    Science.gov (United States)

    Reardon, Fiona; Graham, David A; Clegg, Tracy A; Tratalos, Jamie A; O'Sullivan, Padraig; More, Simon J

    2018-04-01

    A compulsory national programme to eradicate bovine viral diarrhoea virus (BVDv) began in Ireland on 1 January, 2013. The objective of the current study was to quantify the role of Trojan dams (animal(s) not persistently infected (PI) with BVDv but carrying PI foetus(es) and introduced to the herd while pregnant with the PI foetus(es)) in the farm-to-farm spread of BVDv in Ireland, and to identify herd-level risk factors for producing or introducing a Trojan dam. The study population included all BVD+ calves born in Ireland between 1 January, 2013 and 31 December, 2015, along with their dams. BVD+ calves included all calves on the national programme database with an initial positive or inconclusive virus test, without a confirmatory re-test (status BVDPOS) and those with an initial positive or inconclusive test and a positive confirmatory test (status BVDPI). The Trojan status of dams was determined after considering their history of movement and of potential BVDV exposure, relative to a defined window of susceptibility (WOS; days 30-120 of gestation). During 2013-15, there were 29,422 BVD+ birth events to dams that were not themselves BVD+, including 2526 (8.6%) most-likely attributable to Trojan dams. The percentage of these birth events attributable to Trojan dams was significantly different (P Trojan dam. In 2014 and 2015, the percentages were 11.8% and 13.3%, respectively. In 2013, in 7.8% of herds with one or more BVD+ birth to non-BVD+ dams, all of these births were attributable to Trojan dams. In 2014 and 2015, the percentages were 9.2% and 10.7%, respectively. A logistic GEE regression identified dam parity, herd size and an interaction between herd type and season as significant predictors for the birth of a BVD+ calf to a Trojan dam. Significant predictors for the sale of a Trojan dam from BVD+ herds included those selling more than one pregnant female and those with more than 2 BVD+ animals in the herd. Introduction of pregnant adult females is a

  16. Behaviour of Frictional Joints in Steel Arch Yielding Supports

    Czech Academy of Sciences Publication Activity Database

    Horyl, P.; Šňupárek, Richard; Maršálek, P.

    2014-01-01

    Roč. 59, č. 3 (2014), s. 723-734 ISSN 0860-7001 R&D Projects: GA MŠk ED2.1.00/03.0082; GA MŠk ED1.1.00/02.0070 Institutional support: RVO:68145535 Keywords : steel arch yielding support * friction al joints * bolt connection * slip support * fem Subject RIV: DH - Mining, incl. Coal Mining Impact factor: 0.608, year: 2013

  17. Case series: Endoscopic management of fourth branchial arch anomalies.

    Science.gov (United States)

    Watson, G J; Nichani, J R; Rothera, M P; Bruce, I A

    2013-05-01

    Fourth branchial arch anomalies represent branchial anomalies and present as recurrent neck infections or suppurative thyroiditis. Traditionally, management has consisted of treatment of the acute infection followed by hemithyroidectomy, surgical excision of the tract and obliteration of the opening in the pyriform fossa. Recently, it has been suggested that endoscopic obliteration of the sinus tract alone using laser, chemo or electrocautery is a viable alternative to open surgery. To determine the results of endoscopic obliteration of fourth branchial arch fistulae in children in our institute. Retrospective case note review of all children undergoing endoscopic treatment of fourth branchial arch anomalies in the last 7 years at the Royal Manchester Children's Hospital. Patient demographics, presenting symptoms, investigations and surgical technique were analysed. The primary and secondary outcome measures were resolution of recurrent infections and incidence of surgical complications, respectively. In total 5 cases were identified (4 females and 1 male) aged between 3 and 12 years. All presented with recurrent left sided neck abscesses. All children underwent a diagnostic laryngo-tracheo-bronchoscopy which identified a sinus in the apex of the left pyriform fossa. This was obliterated using electrocautery in 1 patient, CO₂ laser/Silver Nitrate chemocautery in 2 patients and Silver Nitrate chemocautery in a further 2 patients. There were no complications and no recurrences over a mean follow-up period of 25 months (range 11-41 months). Endoscopic obliteration of pyriform fossa sinus is a safe method for treating fourth branchial arch anomalies with no recurrence. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  18. Paleogeographic features of Zhiguli arch development in the Frasnian century

    Energy Technology Data Exchange (ETDEWEB)

    Yaroslavtsev, G.A.

    1984-01-01

    The absence of terrigenous masses of the Devonian on the Pokrovskiy apex of the Zhiguli arch is linked by many researchers with the existence here of an island mass. The unsoundness of this hypothesis is substantiated. The absence of terrigenous masses of the Devonian and the occurrence of offshore carbonate deposits of Voronezh age with discordance on the underlying masses is substantiated by the underwater erosion of underlaying masses and recessive accumulation of carbonate Voronezh formations.

  19. Right cervical aortic arch with aberrant left subclavian artery.

    Science.gov (United States)

    Tjang, Yanto S; Aramendi, José I; Crespo, Alejandro; Hamzeh, Gadah; Voces, Roberto; Rodríguez, Miguel A

    2008-08-01

    The combination of right cervical aortic arch, aberrant retroesophageal left subclavian artery originating from a Kommerell's diverticulum, and a ligamentum arteriosum, constitutes a rare form of vascular ring. Two patients aged 21 days and 54 years, who were diagnosed by multislice 3-dimensional computed tomography and magnetic resonance imaging, underwent surgical division of a vascular ring. The adult required resection of a Kommerell's aneurysm and subclavian artery reimplantation.

  20. Hemiarch versus total aortic arch replacement in acute type A dissection: a systematic review and meta-analysis.

    Science.gov (United States)

    Poon, Shi Sum; Theologou, Thomas; Harrington, Deborah; Kuduvalli, Manoj; Oo, Aung; Field, Mark

    2016-05-01

    Despite recent advances in aortic surgery, acute type A aortic dissection remains a surgical emergency associated with high mortality and morbidity. Appropriate management is crucial to achieve satisfactory outcomes but the optimal surgical approach is controversial. The present systematic review and meta-analysis sought to access cumulative data from comparative studies between hemiarch and total aortic arch replacement in patients with acute type A aortic dissection. A systematic review of the literature using six databases. Eligible studies include comparative studies on hemiarch versus total arch replacement reporting short, medium and long term outcomes. A meta-analysis was performed on eligible studies reporting outcome of interest to quantify the effects of hemiarch replacement on mortality and morbidity risk compared to total arch replacement. Fourteen retrospective studies met the inclusion criteria and 2,221 patients were included in the final analysis. Pooled analysis showed that hemiarch replacement was associated with a lower risk of post-operative renal dialysis [risk ratio (RR) =0.72; 95% confidence interval (CI): 0.56-0.94; P=0.02; I(2)=0%]. There was no significant difference in terms of in-hospital mortality between the two groups (RR =0.84; 95% CI: 0.65-1.09; P=0.20; I(2)=0%). Cardiopulmonary bypass, aortic cross clamp and circulatory arrest times were significantly longer in total arch replacement. During follow up, no significant difference was reported from current studies between the two operative approaches in terms of aortic re-intervention and freedom from aortic reoperation. Within the context of publication bias by high volume aortic centres and non-randomized data sets, there was no difference in mortality outcomes between the two groups. This analysis serves to demonstrate that for those centers doing sufficient total aortic arch activity to allow for publication, excellent and equivalent outcomes are achievable. Conclusions on