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 16 of 16 for “"ebullition"”.
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Spatiotemporal variability of methane ebullition from lake sediments
… bubbles, and the spatiotemporal heterogeneity of ebullition makes measurement challenging and impacts bubble dissolution and atmospheric emissions. In this thesis, we present an analysis of both the episodicity and spatial structure of methane venting from soft sediments in a eutrophic lake over a …
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Chemical transport by methane ebullition in a freshwater lake
… bodies experience an order of magnitude more ebullition and bubbling may therefore constitute a significant contaminant flux in these systems. Furthermore, bubbles may also transport organisms (or pathogens) from the sediment to the water surface.
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Comparison of water boiling models against recent experimental data, with special emphasis on the bubble ebullition cycle
… The particular focus of this work is on the ebullition cycle and associated bubble nucleation frequency, looking at the models proposed by M.Z. Podowski. In my analysis, I took the average values for the growth and dwell times directly from the data, rather than from the models for those …
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Magnitude and spatio-temporal variability of methane emissions from a eutrophic freshwater lake
… However, spatial and temporal heterogeneity in ebullition has complicated efforts to accurately measure such methane emissions. This thesis presents the results from a two-year study of methane biogeochemistry conducted at the eutrophic, stratified, Upper Mystic Lake located in eastern …
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Numerical modeling of methane venting from lake sediments
… pressure, appear to trigger free gas bubbling (ebullition). We develop a model of methane bubble ow through the sediments, forced by changes in hydrostatic load. The mechanistic, numerical model is tuned to and compared against ebullition data from Upper Mystic Lake, MA, and the predictions …
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The drivers of freshwater reservoir biogeochemical cycling and greenhouse gas emissions in a changing world
… reservoir and that the environmental drivers of ebullition and diffusion can change substantially both over space (within one hundred meters) and time (within a few weeks). Finally, I developed a forecasting workflow that successfully predicted future CH4 ebullition rates during one summer …
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Identification and validation of screening methods for assessment of the sheening potential of embedded oil in sediments
… petroleum hydrocarbons (oil) may sheen due to ebullition-driven transport or sediment disturbance. The goal of this project was to develop a screening method that can be deployed on a small autonomous watercraft that will provide a reliable indication of sheening potential of embedded oil in …
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Nano-engineering the boiling surface for optimal heat transfer rate and critical heat flux
… to allow for rewetting of the surface during the ebullition cycle and thus maintaining a high critical heat flux. The patterned surfaces exhibited similar critical heat fluxes and heat transfer coefficients to the surfaces that were only modified with layer-by-layer nanoparticle coatings. However, …
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Carbon and electron flow via methanogenesis, So₄²⁻, NO₃⁻ and Fe³⁺ reduction in the anoxic hypolimnia of upper Mystic Lake
… iron minerals and/or the loss of methane due to ebullition and oxidation. Such explanations suggest future studies of UML to better resolve the electron budget. In order to study the redox balance in Upper Mystic Lake, a method was devised for precisely sampling dissolved gases in the water …
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The biogeochemistry of methane isotopologues in marine and lacustrine sediments
… largest set of methane isotopologue data from ebullition in a single lake basin, which is used to gauge the relative importance of aerobic and anaerobic methane oxidation in the study site and recommend a general sampling strategy to constrain methane source signatures in similar lake settings. …
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The Biogeochemistry of Methane Isotopologues in Marine and Lacustrine Sediments
… largest set of methane isotopologue data from ebullition in a single lake basin, which is used to gauge the relative importance of aerobic and anaerobic methane oxidation in the study site and recommend a general sampling strategy to constrain methane source signatures in similar lake settings. …
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Pollutant swapping in constructed agricultural wetlands
… an 18 month period, using floating gas chambers, ebullition traps and diffusive gas exchange models. While the wetland was a net sink of particulate C and N, mean net releases of CO2 (2249 – 5724 mg m-2 d -1 ), N2O (0.93 – 2.04 mg m-2 d -1 ) and CH4 (169 - 456 mg m -2 d -1 ) were significantly …
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Dynamics and Drivers: Carbon fluxes from temperate freshwater reservoirs
… CO2), pH (CO2) and the occurrence of physical ebullition events (CH4), all of which were accentuated by large water drawdowns during the sampling period. This study suggests that system productivity is likely to be the dominant driver of CH4 and CO2 production in reservoirs of the south east of …
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Fundamentals of microlayer evaporation and its role on boiling heat transfer enhancement
… of the process is still lacking. The bubble ebullition cycle (nucleation, growth and departure) happens over a very short time-span (milliseconds) making it challenging to study the near-surface interfacial characteristics of a single bubble, which involves a microlayer. The microlayer is a …
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Carbon dioxide and methane emissions from the Te Arawa lakes of Rotorua, New Zealand
… of the flux. This study did not account for CH₄ ebullition, however, and therefore the magnitude of GHG emissions from this lake is likely to be lower than predicted. The effects on CO₂ and CH₄ emissions from Lake Okaro of a warming climate and changes in nutrient loads was simulated using a …
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Quantifying biophysical and biogeochemical influence on northern high latitudes greenhouse gases dynamics
… by modeled transport processes (diffusion, ebullition, and aerenchyma transport). Non-wetland soils emit CH4 (1.4 TgCH4 yr-1) in some areas and take up CH4 (-2.9 TgCH4 yr-1) in other areas, resulting in a net estimated sink for the 2000s; the net non-wetland soil sink increases by 15% and 46 …