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 20 for “"Density currents"”.
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Modeling and Large Scale Simulations of Thermohaline and Particulate Density Currents
The simulations show in great detail the dynamics of the flow and the rich interaction between turbulent structures with a wide range of scales. Front spreading velocity, Kelvin-Helmholtz vortex dynamics, lobe and cleft formation and evolution, flow patterns, and bed shear stress patterns, are …
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The influence of steps topography on the behavior of density currents – a numerical study
… These bed features are formed by turbidity currents, and in turn, influence the flow characteristics of the density currents and their sediment transport behavior, thus affecting sedimentation in the oceans. To explore the interaction between density currents and stepped topographies, a …
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Bedforms and Gravity Underflows in Marine Environments
… supporting the argument that supercritical density and turbidity currents can develop long-wavelength, upstream-migrating bedforms is presented for the first time. Additional experimental evidence of the coexistence of upstream-migrating antidunes and small-scale downstream-migrating ripples …
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Historic and prehistoric volcanic activity on St Kitts and Nevis, West Indies: Controls on future hazard
… characterised the nature of the pyroclastic density currents (PDCs) on St Kitts and Nevis. Pyroclastic density currents (PDCs) of pumice and ash flows, and surge deposits characterise the youngest products at both Mt Liamuiga and Nevis Peak, although subordinate lapilli fallout deposits also …
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Experiments on transitional regime sediment density flows and resulting deposits
… 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 when turbulence …
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Genesis and Sedimentation of an Ice-Walled Lake Plain in Northeastern Illinois
… deposited through grain settling from hypopycnal density currents, with the particle settling velocities revealing that the laminae were deposited in a short period of time (perhaps weekly or monthly), while cumulative settling times reveal longer periods of non-deposition. These …
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Parameterization of convection in a rotating stratified ocean : comparison of numerical and laboratory experiments with theory
Laboratory and numerical experiments are carried out in a parameter regime relevant to open-ocean deep convection. We consider the case of convection in a rotating stratified ocean of finite depth. Convection is induced from the surface by extracting buoyancy over a circular area. The external …
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Aquatic gravity currents through emergent vegetation
Differential heating and cooling can generate density-driven, lateral exchange flows in aquatic systems. Despite the ubiquity of wetlands and other types of aquatic canopies, few studies have examined the hydrodynamic effects of aquatic vegetation on these currents. This study investigates the …
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The Effect of Arctic River Hydrological Cycles on Arctic Ocean Circulation
… (1) the formation of shelf and basin scale density currents; (2) maintenance of the strong density stratification; (3) control of the thickness and strength of the ice pack; and (4) control of deep convection. Sources and sinks of freshwater in the Arctic include: shoreline discharge as …
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Unresolved Problems Involving the Hydrogeology and Sequence Stratigraphy of the Wasatch Plateau based on Mapping of the Wattis 7.5 Minute Quadrangle, Carbon and Emery Counties, Utah: Insights Gained from a New Geologic Map
… The Emery Sandstone reflects density currents caused by major storm events, including Bauma C and D depositional structures. Thick sandstone bodies are restricted to paleochannels.</p>
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Drivers, Dynamics and Hazards of the largest pyroclastic eruptions of Tongariro Volcano, Central North Island, New Zealand
… eruptions, the latter generating pyroclastic density currents. Peak eruption column heights for these episodes were between 16 and 32 km with volumes of individual tephra lobes reaching 0.76 km³. Via 2D and 3D textural studies, it is shown that these mostly micro-porous pumices erupted via …
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Numerical study on internal flow structures of subaqueous density underflows and stratified open-channel flows
The internal structure of subaqueous density underflows and stratified open channel flows are examined in this study. Three different flow configurations are used to investigate the effects of density stratification on the internal structure and the responses of the structure as flow conditions …
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A GIS-Based Volcanic Hazard and Risk Assessment of Eruptions Sourced within Valles Caldera, New Mexico
… designed to simulate ash fallout, pyroclastic density currents (PDCs), and lava flows based on the Late Quaternary (~55 ka) eruptions from within Valles caldera. Simulated ash fall deposits originating from El Cajete crater are calibrated to isopach and lithic isopleth maps of the Lower and …
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Motility-induced phases: out-of-equilibrium droplets, surfaces, and survival
… quantities like pressure, surface tension, density, currents, and cluster growth exponents of systems of ABPs. All of these quantities can be compared to continuum models and experiments. As described by the main chapters of this thesis, my work has focused on studying the pressure and …
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Simulating organization of convective cloud fields and interactions with the surface
… of convergence lines produced by mesoscale density currents, such as the sea breeze and cold pool storm outflows.
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Secondary Clarifier Modeling: A Multi-Process Approach
The performance of settling tanks depends on several interrelated processes and factors that include: hydrodynamics, settling, turbulence, sludge rheology, flocculation, temperature changes and heat exchange, geometry, loading, the nature of the floc, the atmospheric conditions and the total …
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Materiales anódicos alternativos para el desarrollo de baterías de ión-litio sostenibles
… is comparable, or even superior at high-density currents, to that of oil-derived micrometric graphite, which is used on a large scale for lithium-ion batteries. The nanometric particle size reduces the diffusion time of the Li+ ions along the intercalation/deintercalation processes, …
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Volcanic and sedimentary processes in phreatomagmatic volcanoes
… internal structures indicating deposition by density currents whose flowpower decreased with time and with distance from the vent. Syndepositional slumping and minor en masse collapse of crater deposits formed a pile of massive tuffs above which subsequent surge and airfall activity deposited …
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3-D Numerical Modeling of Turbidity Currents
<p>The hydrodynamics of density currents are difficult to study in the natural envi- ronment, whereas laboratory experiments are limited to small-scale flows, are time- consuming and are not necessarily easier when it comes to measuring flow properties or establishing relationships between the …
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Buoyancy force driven mixing in environmental flows: Theory, observations and numerical modeling
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2025-05-01