Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 125 for “"drawdown"”.
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Stability of Embankment Dams Following Reservoir Drawdown
Empirical relationships for the undrained and effective stress shear strength parameters were established in the present study based on soil plasticity through the results of the laboratory-testing program and stability analyses for 11 embankment dams.
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Rapid Drawdown Analysis using the Finite Element Method
Rapid drawdown (RDD) occurs when the water level adjacent to a slope or embankment is lowered quickly after a long period of being elevated either at the normal operating level for a dam or in the case of levees, during a prolonged flood. The current state of practice for RDD analysis is a …
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Portfolio diversification utilising rolling economic drawdown constraints and risk factor analysis
… termed Factor Adjusted Rolling Economic Drawdown (FAREDD), whereby resources are allocated to different assets by way of integrating Principle Component Analysis (PCA) with existing Rolling Economic Drawdown Methods (REDD). The primary purpose of this model is to create a portfolio with …
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Finite element analysis of embankment dam due to rapid drawdown events
… associated with flood loading or rapid drawdown (RDD) conditions. The assessment of slope stability under RDD conditions is difficult to estimate due to the time-dependence of pore pressures within the dam and uncertainties in the shear strength properties of compacted fills. …
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A method using drawdown derivatives to estimate aquifer properties near active groundwater production well fields
… tests. The parameter estimation method utilizes drawdown derivatives to estimate the aquifer transmissivity and storativity. The forward model consists of an initial water level (or a recoverable water level drift function), an analytical solution for aquifer drawdown, and a correction term for …
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Numerical Investigation into the effects of cavities on stability of slopes and seepage through earth dams under rapid drawdown condition
… presence of cavities in the subsoil and rapid-drawdown conditions. The current work aims to examine the influence of several parameters related to the cavity – such as the location (varying in X and Y directions), shape and diameter of the cavity, and the number of cavities – on the flow rate …
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Impacts of Delayed Drawdown on Water Quality and Aquatic Biota in Seasonal Wetlands of the Grassland Ecological Area, Los Banos, California
… activity is the fall flooding and spring drawdown of wetlands, timed to optimize the availability of forage vegetation and invertebrates for ducks and shorebirds. Wetland drainage contains salt, boron, and trace elements that are, in part, derived from imported surface water but also …
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A finite element analysis of dissolved oxygen drawdown and sulfate production in strip mine spoil dams due to pyritic chemical reaction
The problem of dissolved oxygen drawdown and sulfate production in strip mine spoil dams due to chemical reaction between an excess of pyrite, water, and dissolved oxygen is investigated. A finite element analysis is used to solve the diffusion-convection equation assuming steady state conditions …
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Managing portfolios of products and securities
… we find that in most cases, the maximum drawdown increases as a function of the upper bound on the variance of the portfolio and that this result is consistent with intuition, since portfolio risk increases as the chance that a drawdown event occurs also increases. However, we have …
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The Role of Branching Topology on Rheological Properties and its Effect on Film-Casting Performance
… the film-necking properties. At the lowest drawdown ratio necking is observed to be reduced with increasing LCB, and thus strain-hardening characteristics. At the higher drawdown ratios it is observed that LCB no longer reduces necking and the curves merge to the results found for linear PE, …
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Some Insurance Options on Stochastic Drawdowns
… losses. Thanks to its desired features, drawdowns can be a very useful tool in the marketplace, allowing investors to protect against the downside risks which commonly occur in the marketplace. Several insurance products are proposed via including protection against drawdown sizes, speed …
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Mechanisms of strength loss in stiff clays
… slide occurred at the end of a period of rapid drawdown of the reservoir. Although this was the longest and fastest drawdown in the life of the dam, 180 feet in 120 days, there had been seven previous cycles of drawdown, some nearly as severe as the one that preceded the slide. Field …
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A comparison of field methods of measurement of the water table drawdown characteristics between lateral tile drains in Brookston clay loam soil and an evaluation of an empirical formula for placing lateral drains
Thesis (M.S.)--Michigan State College of Agriculture and Applied Science. Dept. of Agricultural Engineering, 1953
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The impact of behavioral factors on annuitisation decisions and decumulation strategies
… low demand. Another solution is following a safe drawdown rate during retirement; however this exposes retirees to the risk of outliving their pension savings. In recent years, behavioral factors have been successful in explaining individuals’ decision-making process, this thesis is therefore …
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The relationship between slope stability and pore-water pressure in highly plastic clay in the Carrot River Basin
… with models of steady state groundwater flow, drawdown following flooding, and of induced pore-water pressure caused by construction. The flood hydrograph was represented as a total head versus time boundary condition for the transient groundwater seepage model. Factors of safety were …
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Assessment of the hatchery kokanee (Oncorhynchus nerka) release program in Lake Roosevelt 2009 -- 2012
… 2009 and 2010 coincided with relatively shallow drawdown and longer water retention times, whereas, the poor 2011 and 2012 returns coincided with a deep drawdown and shorter water retention times.</p>
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Linking Rheological and Processing Behavior to Molecular Structure in Sparsely-Branched Polyethylenes Using Constitutive Relationships
… the film-casting process is analyzed at various drawdown ratios. A full rheological characterization in both shear and shear-free flows is also presented. At low drawdown ratios, the low-density polyethylenes, LDPE, exhibited the least degree of necking at distances less than the HDPE frostline. …
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Characterization of Subsurface Heterogeneity Using Transient Hydraulic and Tracer Tomography
… temporal moments of well hydrographs, instead of drawdown itself. The governing equations and adjoint equations for the temporal moments are Poisson's equations. These equations demand less computational resources as opposed to the parabolic equation that governs drawdown evolution. Therefore, a …
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Some contributions to the hydraulic characterization of fractured bedrock formations
… two field hydraulic tests were named the large drawdown slug test, and the gas injection test. Large drawdown slug tests are defined as those slug tests with initial drawdown larger than 5 m; these were demonstrated to be a valuable hydraulic test to: (a) study well interconnectivity in …
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