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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 20 for “"Cohesive sediment"”.
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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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Two-phase Flow Modelling of Mud Flocs Sedimentation in Coastal Waters
Cohesive sediments can be found widely such as on continental shelves, at estuaries and in coastal waters. Various engineering problems such as siltation of navigation channels and polluting coastal environment can be caused by the cohesive sediments. To solve these problems, field/lab experiments …
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Sediment erosion and deposition within mangrove forests
… in their own biomass and by trapping carbon-rich sediment imported from outside the forest and deposited in the forest. Aboveground biomass, like mangrove pneumatophores (i.e., aerial roots), creates conditions that facilitate sediment deposition by enhancing drag and slowing currents near the …
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Sediment Erosion and Deposition Within Mangrove Forests
… in their own biomass and by trapping carbon-rich sediment imported from outside the forest and deposited in the forest. Aboveground biomass, like mangrove pneumatophores (i.e., aerial roots), creates conditions that facilitate sediment deposition by enhancing drag and slowing currents near the …
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Experiments on transitional regime sediment density flows and resulting deposits
Much remains unknown regarding the sedimentary deposits of submarine density flows. Certain density flows may transition from a more turbulent to a more coherent flow regime e.g. by a loss of velocity in flows with large concentrations of suspended sediment. Such transitional flows are produced …
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THE EFFECT OF RAIN ON INTERTIDAL ESTUARINE SEDIMENT TRANSPORT (VORTEX RINGS, OXYGENATION, DROP/SPLASH FEATURES, FECAL PELLETS)
… to understand how raindrops may be acting as a sediment resuspension mechanism. Single-drop and multi-drop laboratory studies were conducted on the initiation of motion of sediment. Results indicate single vortex rings in a quiescent environment can initiate motion of sand-sized noncohesive …
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Turbulence In Low Energy Lacustrine Environments At The Sediment-Water Interface
The sediment-water interface is an important region where biological, chemical, and physical processes occur. Fluid flow determines the ability of organisms to utilize the bottom sediments for food, shelter, and reproduction, the amount and rate of mass transfer between the sediment and bulk fluid, …
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Entrainment of Sediment by Unsteady Turbulent Flows
… was gathered that demonstrates the response of sediment to unsteady flows. The data that were gathered include temporal distributions of sediment concentration, shear stress, and velocity for two types of flow conditions: tests where the flow was increased from rest to a peak velocity and was …
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Effect of self-stratification on channel flows and boundary layers: a study using direct numerical simulations
Flows with suspended sediment are one of the most prevalent type of flows in nature. They can be found in nature as hypoconcentrated flows, mudflows, lahars and turbidity currents, to name a few. Effect of suspended sediment on the flow has wide ranging impact on geomorpholoy, ecological health, …
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Improvements to the Modeling of Average Floc Size in Turbulent Suspensions of Mud
The accuracy of sediment transport models depends on identifying an appropriate sediment settling velocity. Determining this value for mud suspensions can be difficult because cohesive mud particles can aggregate, forming flocs whose sizes are a function of hydrodynamic and physiochemical …
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Interaction of Clay Wash Load With Gravel Beds
… gravel bed rivers. The effects of excess fine sediment loading to streams on general water quality, contaminant transport, and benthic organism mortality has been well examined. A fundamental assumption in fluvial geomorphology and river engineering is that wash load particles ($d<63mu m$) do …
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Dynamical Sedimentary Models of Shallow Marine Environments
… a contribution of quantitative, dynamical sedimentary modeling to the analytical understanding of sedimentary processes in shallow marine environments. The dynamical sedimentary models in this treatise numerically simulate the sedimentary processes from an event time scale, based on the …
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Do Muds Sort? Experimental Test of a Hypothesis Key to Understanding Marine Bottom Currents
Accumulations of fine sediments in deep-ocean contourites form a sedimentary record that has been hypothesized to be directly related to bottom-current behavior. This is known as the 'sortable silt' hypothesis and states that the non-cohesive, coarse silt in the 10 to 63 µm size range within a …
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Experiments on the Transformation of Mud Flocs in Turbulent Suspensions
… one of the most crucial parameters influencing sediment transport modeling. A series of laboratory experiments were conducted to examine the impact of suspended sediment concentration, mixes of clay and silt, and resuspension process to equilibrium floc size and floc settling velocity. In order …
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Seasonal Variation of Mud Floc Sizes in Two Small Freshwater Streams
Flocculation is not only an important part of sediment dynamics within coastal marine waters, but is also a factor of sediment transport within small freshwater streams in Blacksburg, Virginia. The goal of this project was to develop a relationship between floc sizes and stream characteristics …
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Studying physical and biological aspects of coastal suspended particulate matter (SPM) dynamics using a novel distribution-based flocculation (DBFloc) model
… ist das DBFloc Modell potenziell geeignet, in Sedimenttransport- und Ökosystemmodellen Anwendung zu finden.
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The Development of an In-situ Mud Floc Microscope Imaging Device and In-situ Floc Observations from the Lowermost Mississippi River
Mud makes up a large fraction of sediment transported within rivers to the coasts. Predicting where mud will settle is complicated by the cohesive nature of silts and clays, which can combine to form larger aggregates known as flocs. The size and density, and consequently, the settling velocity, of …
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Large-scale floodplain sediment dynamics in the Mekong Delta : present state and future prospects
… one of the world’s most productive fisheries. Sediment dynamics play a major role for the high productivity of agriculture and fishery in the delta. However, the MD is threatened by climate change, sea level rise and unsustainable development activities in the Mekong Basin. But despite its …
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Influence of riparian vegetation on near-bank flow structure and rates of erosion on a large meandering river
… flow structure, channel planform geometry, and sediment transport. These internal processes can be strongly influenced by the geotechnical properties of the channel banks and floodplains, as well as riparian and in-channel vegetation, modifying rates of erosion and mechanism of bank retreat, …