Nach oben pdf Plunge Pool Design at Gebidem Dam (Switzerland)

Plunge Pool Design at Gebidem Dam (Switzerland)

Plunge Pool Design at Gebidem Dam (Switzerland)

Gebidem Dam is a 122 m high double curvatured arch dam with plunge pool concrete apron situated in the canton of Wallis, Switzerland (Figure 1). The dam reservoir collects glacier water of the longest glacier in Europe, i.e. the Aletsch glacier (25 km length), which is very rich in sediment. This results in huge amounts of fine sediments depositing into the reservoir. The 55 m 3 /s turbined by the Bitsch power station contain between 10 and 13 kg of sand, or an average of almost 40 tons per hour.

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Rock Plunge Pools: A Design Approach for Limiting Scour Extent

Rock Plunge Pools: A Design Approach for Limiting Scour Extent

When plotting the dimensionless maximum fissure pressure ( P max_ pool / H where H = kinetic energy head of the jet) as a function of dimensionless plunge pool depth ( Y D / ) it is found that the maximum pressure occurs at a depth of approximately eight times the jet dimension. This does not mean that the maximum plunge pool is at approximately eight times the jet dimension, but this relationship can be used to assess the maximum scour depth by considering the brittle fracture and fatigue characteristics of the rock (Bollaert 2002). This is done by calculating the stress intensity in a fissure and comparing it with its fracture toughness. The complete procedure for doing this is quite involved and, due to space limitations, is not repeated here. It is useful to note that the maximum pressure decreases to minimal values at dimensionless depths of 15 or more. Obviously, the absolute value of the maximum pressure will be a function of whether the jet is intact or broken and can be determined using approaches referred to in the previous section.
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Kariba Dam Plunge Pool Scour

Kariba Dam Plunge Pool Scour

Determination of the extent of scour is an important factor in the design of dams and spillways. The case study presented herein for Kariba Dam provides a practical application of the total dynamic pressure coefficient with Annandale’s Erodibility Index Method (EIM) and Bollaert’s Comprehensive Fracture Mechanics (CFM) and Dynamic Impulsion (DI) models. The total dynamic pressure coefficient has been developed to incorporate the effects of jet break up on the average and fluctuating dynamic pressures. The maximum scour depth predicted using the above methods shows very good agreement with the scour observed at the site to date.
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Hiring from a pool of workers

Hiring from a pool of workers

1. Introduction While most companies are free to use almost any criteria to decide which workers to hire and when, that is not the case in many governments and institutions around the world. In order to reduce the agency problems of government institutions and increase the transparency of the hiring process, those institutions have to follow clear and strict criteria for selecting workers. In particular, when the number of workers hired is large (such as police officers, tax agents, etc,) the selection procedure may consist of several steps, such as written exams, physical and psychological tests, interviews, and so on, which may also be time consuming. Due to the high costs of executing such selection procedures, these hirings often take place in two phases: the evaluation phase, in which workers apply for the job and take part in the above-mentioned tests and exams, and the second phase, in which the institutions select, over time and on a need basis, workers from the “pool” of workers who took part in the first phase. After a certain period of time, the pool of workers is renewed, with new ones coming through a new evaluation phase. As described by the Public Service Commission of the New South Wales government:
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Scenarios for embedding AI in Acoustic Design. Exploiting applications at several design stages

Scenarios for embedding AI in Acoustic Design. Exploiting applications at several design stages

Today, digital tools handle large complex problems evolving from generative into intuitive tools such as the Artificial Intelligence (AI). AI, through the deep learning, discovers intricate structure in large data sets, by using the backpropagation algorithm, to indicate machine’s way to change its internal parameters thus helping to develop unpredictable innovative solutions. The paper intends to develop a theoretical background based on bibliographic survey of AI in architecture, with a focus on acoustics. The resultant reading grid will be implemented by a custom survey sent to main stakeholders of acoustic design aiming at understanding strength and weaknesses of its application.
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The Kambarata 2 blast-fill dam, Kyrgyz Republic : blast event, geophysical monitoring and dam structure modelling

The Kambarata 2 blast-fill dam, Kyrgyz Republic : blast event, geophysical monitoring and dam structure modelling

Background Natural blockages formed by bedrock landslides may persist for several tens, hundreds or thousands of years and thus could store large amounts of water, posing a potential threat to communities living downstream, sometimes hundreds of kilometres from the dam site. It can be exemplified by the catastrophic breach of a dammed lake in the upper reaches of the Rio Barrankos in Argentina (Hermanns et al. 2011), after which the flood travelled for about 1000 km before reaching the Atlantic Ocean. Studies of such features face difficulties due to their size, complexity and irregularity of in- ternal structure. The presented case study relates to the investigation of the internal structure of a com- bined blast-fill and earth-fill dam of the Kambarata 2 Hydropower Plant (KHPP-2) and describes a set of geophysical tools and hydro-geomechanical analyses that could also be used to also assess the stability of (possibly much larger) natural dams. An application of similar methods to such a natural dam is presented in Torgoev et al. (2013).
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Asphalt facing for Al Sourani Dam in Syria

Asphalt facing for Al Sourani Dam in Syria

The advantageous characteristics of an Asphaltic lining in relation to its basic requirement, namely impermeability to water that it can absorb pressure forces as well as bending and shearing forces, and up to a certain limit, it is compatible with regard to consolidation settlements. To a certain extent, as a result of the visco- elastic characteristics of the bitumen, tensile stresses in the film of the bonding agent between the adjacent grains of mineral can be reduced without the development of cracks. This feature, exploited in the Asphaltic linings with large areas, can be produced without seams. Asphaltic mixes can be composed in such a way that in addition to the desired consistency and flexibility they also have sufficient suitability to be placed on slopes with an inclination of up to 1:1.3,[ Shoenian, E ,1999].The first use of the Asphaltic concrete in Syria was the sealing of Al-Sourani Dam in Tartous by the use of asphalt facing with an inclination of 1:2.25. The construction of the asphalt facing was finished in Nov. 2003.In this paper, we shall explain the property of the construction materials, lining design, quality control, and thermal condition such semi-arid area.
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Optimizing attraction flow for upstream fish passage at a hydropower dam employing 3D Detached-Eddy Simulation

Optimizing attraction flow for upstream fish passage at a hydropower dam employing 3D Detached-Eddy Simulation

lated. Fishways at most of their dams are either non-existent or non-operational, preventing migratory fish from accessing impor- tant upstream spawning and rearing habitats. Motivated by timely compliance with the requirements of the European Water Frame- work Directive, the Federal Waterways Engineering and Research Institute (BAW) and Federal Institute of Hydrology (BfG) embarked on an intensive program to develop guidelines that address critical questions associated with effective fishway designs and operations. The selection of attraction flow rate is one of the fundamental tasks. The two major biological goals of fishway attraction design for upstream migrating fish are maximizing fish entry rates and minimizing search durations. Two design questions are crucial for meeting these goals: “Where should the fishway entrance be
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Cabora bassa-Dispute about a dam

Cabora bassa-Dispute about a dam

This Version is available at: http://hdl.handle.net/10419/138410 Standard-Nutzungsbedingungen: Die Dokumente auf EconStor dürfen zu eigenen wissenschaftlichen Zwecken und zum Privatgebrauch gespeichert und kopiert werden. Sie dürfen die Dokumente nicht für öffentliche oder kommerzielle Zwecke vervielfältigen, öffentlich ausstellen, öffentlich zugänglich machen, vertreiben oder anderweitig nutzen.

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Reservoir sedimentation in the Demirköprü Dam, Turkey

Reservoir sedimentation in the Demirköprü Dam, Turkey

lake and shows morphological changes of the re- gion (see the image showing the region in Figure 8). Even it is expected that sediment deposition is initially focused in the deepest part of the cross- section, creating deposits having a near- horizontal surface regardless of the original sec- tion shape; this is not the case for Section 1-1. This is actually due to locally sediment inflow from the Gediz River and channel erosion during drawdown in dry seasons. Therefore, it is clearly observed from Figure 7 that while the cross sec- tional shape in 1977 is almost horizontal, in 1991 the central part is scoured forming a main channel with deposited sediments at the banks of the channel.
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Modelling a Landslide Generated Dam Overspill

Modelling a Landslide Generated Dam Overspill

Danìk, M.; Haluza, M. (1997): Modelling a Landslide Generated Dam Overspill. In: Technische Universität Dresden, Institut für Wasserbau und technische Hydromechanik (Hg.): Sanierung und Modernisierung von Wasserbauwerken, aktuelle Beispiele aus Deutschland, Polen, der Slowakei und Tschechien. Dresdner Wasserbauliche Mitteilungen 10. Dresden: Technische Universität Dresden, Institut für Wasserbau und technische Hydromechanik. S. 435-442.

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Erosion in the Foundation of Abshineh Dam (Iran)

Erosion in the Foundation of Abshineh Dam (Iran)

permeability. Meanwhile, the piezometers of this zone had many things to tell; in other words, analysis of the data of piezometers A7d and A10, located at the weathered rock of foundation, showed that a high rate of erosion has occurred after impounding. In fact, there is a big difference between the data before and after impounding. As a matter of fact, the backward seepage analysis demonstrates that if K x = K y = 10 − 4 cm/s, the pore pressure is in agreement with the data of piezometers which do very well correspond with each other; so has high rate of erosion occurred in this zone. This fact confirms the result of the other zones, and proves the erosion-able nature of the Abshineh dam's foundation. Accordingly, three important conclusions can be drawn from the analysis of this zone: first, no grouting in this
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Fishing in the same pool: Export strengths and competitiveness of China and CESEE at the EU-15 Market

Fishing in the same pool: Export strengths and competitiveness of China and CESEE at the EU-15 Market

Version: May, 2012 Abstract We investigate the impact of the emergence of China as a global competitor on the trade performance of Central, Eastern and Southeastern European (CESEE) countries at the EU-15 market. The paper takes a comprehensive approach in terms of empirical methods and data. We analyze export growth, export market shares, extensive and intensive margins and the number of trade links, applying highly disaggregated data at the 6-digit HS level over the period 1995 – 2010. We show that the most contested markets are those for capital goods and transport equipment, product categories where both regions have gained market shares and comparative advantage. We show that the number of trade links at the product level where both regions are active has increased substantially, indicating intensified competition. At the same time hardly any trade links were lost, which points against cut-throat competition between CESEE and China. The decomposition of export growth along the extensive versus the intensive margin shows that in line with the literature, the deepening of already existing trade relationships (i.e. the intensive margin) contributed most strongly export growth in both regions, whereas the contribution of new trade links (i.e. the extensive margin) had only a minor contribution, apart from the instance of EU accession which boosted the extensive margin considerably. We further decompose intensive margin growth into demand related structural effects and a supplier related competitiveness effect. Both the CESEE region and China successfully intensified their trade linkages above all as a result of their outstanding competitiveness as shown by the econometric shift-share analysis. While this suggests that both regions pursue a able export strategy, further
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Forecast uncertainty, disagreement, and the linear pool

Forecast uncertainty, disagreement, and the linear pool

The optimal weights differ for each pool. For the VULP, the minimal Dawid-Sebastiani score is attained at ω 1 ∗ = 0.4. For the other pools, however, it is optimal to reduce the bias of their variance forecasts at the cost of lower accuracy of their mean forecasts. For the CLP, the smallest Dawid-Sebastiani score is reached at ω 1 = 0.37. For the LP, which has a larger variance bias than the CLP, a considerably smaller weight of ω 1 = 0.24 turns out to be optimal. Similar observations apply to the logarithmic score, where the optimal weights for the VULP and the CLP are virtually the same as for the Dawid-Sebastiani score, although the forecast densities are non-normal. For the LP, the optimal weight equals ω1 = 0.3. Since the LP’s scores are flatter due to its higher variance bias, these simulation results indicate that finding optimal combination weights for the LP is likely to be more difficult than for the CLP in empirical applications. Like in the first case, with respect to both scores the LP performs worst for a wide range of weights around ω ∗ 1 , and the VULP performs best.
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Large Eddy Simulation of DTBP Pool Fires

Large Eddy Simulation of DTBP Pool Fires

The utilization of presented technology was proposed and tested feasible, however further development is needed to investigate the potential for a future industrial application. Therefore, the main path of this project is planning, design, construction and operation of an experiment using molten metal as heat transfer medium in a bubble column-type reactor for hydrogen generation by methane pyrolysis. In a first step the focus of this activity will be on possible options of structure material for the chemical reactor and for the bubbling device. Since it is envisaged to operate the chemical reactor at high temperature up to 1000°C in liquid metal and in presence of carbon coke and hydrogen, it is of outmost importance to select high temperature strength materials which are not only compatible with the high temperatures, but they must also be chemically resistant to tin and solid carbon. There are several material options that have to be considered to meet these requirements as e.g. Mo, W, Ta, ceramics, quartz and other materials. The hydrogen yield of the reactor is depending on several operational parameters. In detail, several parameters need to be discussed and put into relation towards the methane conversion/hydrogen production.
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VNUML-Installation im Windows-Pool an der Universität Koblenz-Landau

VNUML-Installation im Windows-Pool an der Universität Koblenz-Landau

Nachdem nun eine Image-Datei für coLinux in einer akzeptablen Größe vorliegt und alle nötigen Konfgurationsdateien an die geforderten Ansprüche angepasst wurden, wird an dieser Stelle [r]

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Der Peer-Info-Pool. Online Studienberatung von Studierenden für Studierende

Der Peer-Info-Pool. Online Studienberatung von Studierenden für Studierende

Mit der Einrichtung und Gestaltung des Peer-Info-Pools konnten viele positive Er- fahrungen gesammelt werden. 2 Als besonders bemerkenswert erscheint uns in dem Zusammenhang die durchweg hohe Motivation der Studierenden, die sich während des gesamten Arbeitsprozesses zeigte. Aus unserer Sicht lässt sich die motivierte Haltung der Studierenden mit der besonderen Konfiguration des Projektes erklären. Im Peer-Info-Pool wurden Themen aufbereitet, die das erfolgreiche Absolvieren eines Studiums fördern sollen. Damit wies er für die Studierenden, die die Lernmo- dule zu den verschiedenen Themenfeldern erstellten, selbst eine hohe inhaltliche Relevanz auf. Darüber hinaus bestand mit der freien Wahl des Lernmodulthemas die Möglichkeit, sich einen individuellen Zu-
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Blood-pool Kontrastmittel-verstärkte Ganzkörper MR Angiographie

Blood-pool Kontrastmittel-verstärkte Ganzkörper MR Angiographie

pool-Phase des Kontrastmittels, Verwendung. Ermöglicht wird die Steady-State- Bildgebung mit Blood-pool Kontrastmitteln durch die lange intravasale Verweildauer. Die Substanz des Kontrastmittels ist ein Trinatrium Salz des Gadolinium(III)-Komplexes Gadofosveset. Die Eigenschaft, dass Gadolinium(III)-Komplexe die T1-Zeit von Wasserstoffprotonen verkürzen, ist die Grundlage für den Einsatz als Kontrastmittel in der MRA. Bisher verfügbare extrazelluläre Gadolinium(III)-Komplex-basierte Kontrastmittel nutzen folgende Eigenschaft, um die Relaxationszeit von Wasser zu verkürzen: Sie wirken durch ein konjugiertes Wassermolekül wie ein Katalysator auf die umgebenden Wassermoleküle und erhöhen somit deren Relaxation („inner-sphere relaxation“). Der Gadolinium(III)-Komplex erzeugt mit seinen sieben ungepaarten Elektronen ein magnetisches Moment. Wenn der Gadolinium(III)-Komplex nun von Wasserstoff-Protonen umgeben wird, entstehen Fluktuationen im lokalen Magnetfeld, die sich relativ nahe an der Lamorfrequenz befinden. Die T1-Relaxationszeiten von umgebenden Wasserstoff-Protonen werden somit verkürzt, was zu einer verstärkten Signalintensität auf T1 gewichteten Bildern führt. Somit werden Strukturen, die eine hohe Gadolinium(III)-Komplex Kontrastmittelkonzentration aufweisen, im T1 gewichteten MR-Bild hyperintens dargestellt. Allerdings zeigte sich, dass die bisher klinisch eingesetzten extrazellulären Gadolinium(III)-Chelate weit vom Optimum entfernte Relaxationseigenschaften aufweisen, da die Fluktuationen nicht – wie gewünscht – nah genug am Frequenzbereich der Lamorfrequenz liegen [40].
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Benefit-sharing in dam projects on shared rivers

Benefit-sharing in dam projects on shared rivers

— The purpose(s) of a dam on a shared river is (are) to achieve national (or sub-national) development objectives. — Each state’s specific interest in cooperation. The hydro-political constellation and the purpose(s) therefore determine a dam’s benefit, cost and externality streams. In the following, the study identifies typical constellations and, for each constellation, potential reasons and incentives for states to cooperate. In do- ing so, it initially conceptualizes states as unitary actors. This, however, is an abstraction for analytical reasons in order to understand the incentive structure at the international level. This does not imply that we suggest that states are unitary actors. To the contrary, international negotiations have to be conceptualized as two-level games (Putnam 1988): at the international level, state representatives negotiate international agreements that seek to generate net benefits for the country as a whole. At the national and sub-national level, the political process determines whether a respective international agreement will be ratified. Depending on the opportunities of affected population to voice their concerns, this na- tional level process may – and we argue that it should – involve negotiations on the com- pensation of and benefit-sharing with those who are negatively affected by the interna- tional agreement.
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Two dimensional modeling of dam-break flows

Two dimensional modeling of dam-break flows

This test problem is the experimental case de- signed by Soares-Frazão et al. (1998) for verifying the capability of numerical methods to simulate dam-break flows. The flow domain consists of a square reservoir and L-shaped channel as shown in Figure 8. The bottom level of the channel is 0.33 m higher than the bottom level of the reser- voir, which means that there is a step at the en- trance of the channel. Initially, the water depth was 0.53 m in the reservoir which is separated by a gate from the channel and then the gate is sud- denly opened to produce a dam-break situation. The water depth in the channel was set to 0.01 m. Taking into account the effect of the bottom and the chute walls the average friction coefficient in
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