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.
Results
Showing 1 to 20 of 21 for “"Sediment bed"”.
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The movement of cohesive sediment in a large combined sewer
The presence of sediment deposits within sewerage systems may lead to operational (premature surcharging and surface flooding) and potential environmental problems (sediments act as a store of pollutants which can be released during erosion events). The consequences of allowing these problems to …
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Active and Passive Settling By Marine Benthic Nematodes
… using two treatments defined by the type of sediment bed placed in the flume. One treatment bed contained sediments rendered "unattractive" by boiling. The other treatment bed contained unaltered "attractive" sediment. Preliminary still water choice experiments confirmed the attractive and …
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Evaluating the combined use of three-dimensional hydrodynamic modeling and polyethylene passive sampling in the Lower Duwamish Waterway
… of contaminants in air, surface water, and sediment bed porewater. This sampling technique can be coupled with a three dimensional (3D) hydrodynamic model of a given surface water body to identify where sources contributing to the measured concentration distribution are most likely located …
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Experiments to culture juvenile freshwater mussels in small tanks, floating containers and sediment beds
… and floating containers were used outdoors, and sediment beds and floating containers were used in indoor culture experiments. Culture experiments with indoor sediment beds produced modest growth rates and variable survival rates for up to 4 months. Shell lengths of juveniles increased from 0.38 …
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A continental shelf bottom boundary layer model : the effects of waves, currents, and a movable bed
… a combined wave and current flow over a moveable sediment bed. An eddy diffusivity closure scheme that includes the effect of suspended sediment, temperature, and salinity induced stratification on the vertical turbulent diffusion of mass and momentum couples the resulting unsteady conservation …
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Evolution of a non-cohesive granular bed subject to a succession of erosive turbidity currents
… study the evolution of a non-cohesive granular bed subject to a succession of erosive turbidity currents to evaluate the applicability of a proposed interface model that prescribes a relationship between the bed shear stress and the local bed elevation and local bed slope. This study considered …
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The effect of fluid acceleration on sediment transport in the surf zone
… The consequences of this dissimilarity on sediment transport is not fully understood. This thesis develops methodologies to predict sediment transport under these asymmetric, skewed waves. Two different transport mechanisms are considered: bedload transport and "subsurface" transport. The …
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The influence of current and ripple development on seagrass transplant survival
… with living shoots were transplanted into a sediment bed and exposed to unidirectional flow in a flume. In accordance with planting techniques reported to improve restoration performance, garden staples were utilized to anchor transplants to the bed. Three flow conditions of increasing …
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Polyethylene devices and the effects of sediment resuspension on the cycling of PAHs and PCBs in the lower Hudson Estuary
In order to examine the importance of sediment resuspension on the sediment bed-to-water column transport of hydrophobic organic contaminants (HOCs) in the lower Hudson Estuary, the following areas of research were pursued: 1) a passive, in situ sampler, a polyethylene device (PED), for measuring …
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Physical modelling of colloidal slurry flows
… formation of aggregates, thus influencing the sedimentation, sediment bed structure and pipeline transportation properties. Silica aggregates formed in IM electrolytes are on average 5.75 times bigger than the primary particle. Pipeline transportation studies have shown the aggregated …
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Performance Analysis of an Urban Stormwater Best Management Practice Retrofit
… with the SOL method showed removal of suspended sediment, nitrogen, iron, and copper. Export of dissolved solids, phosphorus, organic carbon, and manganese was observed. The results of the Effluent Probability Method showed statistically significant reductions of sediment, iron, and copper across …
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Enhancement of fine particle deposition to permeable sediments
… for the potential control of deposition by bed roughness, but no direct tests involving flat sediment beds. Understanding the mechanisms at work for flat sediment beds would provide the basis for exploring more complicated bed conditions and the incorporation of other transport processes, …
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Mechanisms of Sediment Entrainment and Transport in Rotorcraft Brownout
… induced by a small-scale rotor hovering above a sediment bed was studied using high-speed flow visualization and particle image velocimetry (PIV). The high frame rate of the camera, combined with advanced particle recognition and tracking software, permitted an understanding of the temporal …
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Modeling macroalgae growth to optimize biomass.
… simulated macroalgae grown only on the sediment bed, this restriction was lifted to facilitate simulation of kelp farms where the macroalgae substrate was specified at the depth in the water column yielding maximum growth due to optimum light intensity and temperature. The vegetative …
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Polyethylene passive samplers for measuring hydrophobic organic chemical concentrations in sediment porewaters and their use in predicting bioaccumulation in soft-shell clams (Mya arenaria) from sites near Boston, MA
… posed by hydrophobic organic compounds (HOCs) in sediment beds, the following areas of research were explored: (1) the use of polyethylene (PE) sheets as passive sampling devices in sediments, using performance reference compounds (PRCs) in order to reduce deployment times to the order of days, …
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Variabilidad espacio-temporal de la porosidad de la arena tras una regeneración de playa
… placed, is of interest. This region can be described by features such as the pore size, density, porosity, permeability and water content. The bulk density is an indicator of soil compaction, which is related to its porosity and permeability. Beach nourishment features are based on several clues: …
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Multi-scale modeling of the hydrodynamics, sediment transport, and morphodynamics in the nearshore
… to study the hydrodynamics and the underlying sediment transport and morphodynamics for a variety of bed sediment configurations under different wave conditions. First, using a laboratory-scale model (scale of meters) the detailed fluid-sediment interactions were simulated followed by …
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Improved dynamics modelling for drainage sediment prediction and management
… in this thesis aims to further knowledge of sediment behaviour and provides engineers with appropriate tools and methods to facilitate proactive sediment management. The techniques developed during this investigation are therefore able to predict the locations and quantities of sediment …
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Local scour at bridge piers
… in both uniform and non-uniform cohesionless sediments was investigated experimentally. The aim of the study was to improve understanding of local scour around bridge piers with sediment transport. Three empirical functions which relate the equilibrium depth of scour with approach velocity, …
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