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 39 for “"Dissolved gases."”.
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Rheology of molten polystyrene with dissolved gases
Dissolved gases in polymers behave as excellent plasticizers, reducing viscosity significantly through the chain dilution effect and the addition of free volume. Rheological measurements and theoretical modeling are presented for molten polystyrene with dissolved gases, including carbon dioxide, …
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Monitoring dissolved gases and ions in groundwater using an in situ technique
… concentrations of aqueous chemical species and dissolved gases in groundwater. We deployed in situ samplers in 8 wells completed in the glacial Glasford formation and underlying Banner formation of the Mahomet aquifer, a regional water supply in east-central Illinois. We distributed and …
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The undrained behavior of saturated, dilatant silts
… performed to investigate whether cavitation and dissolved gases exiting solution from soil pore water are the cause of the erratic undrained behavior often observed in triaxial tests on saturated, dilatant silts. The literature indicates that ground water contains various amounts of dissolved …
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Ultrasound induced cavitation and sonochemical effects
… contains a combustible gas mixture. Third, the dissolved gases affect the activities of a sonochemical event through both thermal effect by changing the peak collapse temperatures in the bubble and chemical effect by directly participating in reactions. In addition, a laboratory scale …
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Carbon and electron flow via methanogenesis, So₄²⁻, NO₃⁻ and Fe³⁺ reduction in the anoxic hypolimnia of upper Mystic Lake
… a method was devised for precisely sampling dissolved gases in the water column. Like other stratified lakes, UML has a large amount of anaerobic metabolism of organic matter occurring in the sediments and a subsequent accumulation of methane (CH₄) and carbon dioxide (CO₂) in the hypolimnia. …
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The effect of carbon dioxide on the growth and activity of leptospirillum ferriphilum
… terms of typical iron concentration, presence of dissolved salts and dissolved gases. This study focuses particularly on the kinetic description of the microbial ferrous oxidation rate and the microbial growth rate of the Leptospirillum species under conditions where the supply of carbon dioxide …
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Sonoluminescence as a probe of acoustic cavitation
… from Cr(CO)$\sb6$ was studied as a function of dissolved gases to determine the effect of thermal conductivity and $\gamma$ (C$\sb{\rm p}$/C$\sb{\rm v}$) on cavitational conditions. As predicted by thermal theories of sonoluminescence, the intensity of excited-state chromium emission decreases …
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Establishing High-Resolution Hydrogeological, Geochemical and Isotopic Baseline Conditions of the Fresh Water Zone at a Field Research Site Near Brooks, Alberta, Canada
A high-resolution baseline characterization of dissolved gases in groundwater at the CMC field research site from 25.0 to 106.3 m depths was conducted. Data was collected from a continuously cored 106.3 m deep borehole, a 100.0 m deep Westbay® multi-level system and a 67.1 m deep domestic well. The …
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Measurement of Dissolved Gas Concentrations in Natural Waters Utilizing an In-Situ, Membrane Inlet, Linear Quadrupole Mass Spectrometer
… (GSV) and ship's cables to monitor a suite of dissolved gases and volatile organic compounds in saltwater and freshwater environments. Spectrometer data in Lake Maggiore, Florida were acquired at a rate of 0.7-3.6 seconds/sample for 2-3 hours. The resulting multi-analyte spectrometer data were …
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Water Treatment: Fundamentals and Practical Implications of Bubble Formation
… entrainment and ozonation are the key causes of dissolved gas supersaturation and eventual bubble formation in water treatment plants. Total dissolved gas probes (TDGP) are now available to directly measure supersaturation and have many advantages compared to conventional techniques. Bubble …
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Greenhouse Gas Production and Nutrient Reductions in Denitrifying Bioreactors
… of a novel analytical method to quantify dissolved gases in environmental water samples using gas chromatography mass spectrometry was undertaken. Although static headspace analysis is a common technique for quantifying dissolved volatiles, the variation in sample preparation has recently …
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Characterization and numerical simulation of the microstructural and micromechanical viscoelastic behavior of oil sands using the discrete element method
… void spaces are filled with bitumen, water, and dissolved gases. The electric rope shovel is the primary equipment used for excavating the Athabasca oil sand formations. The equipment's static and dynamic loads are transferred to the formation during excavation and propel. These loads cause …
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Cavitation and Bubble Formation in Water Distribution Systems
… Classical cavitation experiments which disregard dissolved gas are not directly relevant to natural water systems and require a redefined cavitation inception number which considers dissolved gases. In a pressurized water distribution system, classical cavitation is only expected to occur at …
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High-Resolution In Situ Oxygen-Argon Studies of Surface Biological and Physical Processes in the Polar Oceans
… use of high-resolution measurements of surface dissolved gases, primarily O2 and Ar, as tracers or physical and biological functioning that we measure underway using an optode and Equilibrator Inlet Mass Spectrometry (EIMS). Total O2 measurements are common throughout the historical and …
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The biogeochemistry of methane isotopologues in marine and lacustrine sediments
… situ concentration of methane based on ratios of dissolved gases, and its comparison to four other methane quantification methods for surface sediments from marine cold seeps. The findings from this research contribute to ongoing efforts to understand the sedimentary carbon cycle and microbial …
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Tracking Sargassum in the Caribbean: the design, deployment, and validation of a low-cost surface drifter
… entanglement and enables the measurement of dissolved gases. The chemical sensing capabilities enhance the understanding of Sargassum rafts’ dynamics and their environmental impact. The thesis concludes by summarizing the key findings and implications of the research. The low-cost surface …
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Characterization of air-sea gas exchange processes and dissolved gas/ice interactions using noble gases
… the cycles of biogeochemically important gases such as 02 and C02, and thereby infer rates of biological activity in the upper ocean or the uptake of radiatively important "greenhouse" gases, the noble gases are used to characterize and quantify the physical processes affecting the …
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The role of dissolved gas fluxes on the biogeochemical evolution of nutrient cycles in lakes.
… of biogeochemical cycles, as the interactions of dissolved gases between the water column, sediment, and atmosphere are important for determining the dynamics of an ecosystem.
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Tracking Sargassum in the Caribbean: The Design, Deployment, and Validation of a Low-Cost Surface Drifter
… entanglement and enables the measurement of dissolved gases. The chemical sensing capabilities enhance the understanding of Sargassum rafts' dynamics and their environmental impact. The thesis concludes by summarizing the key findings and implications of the research. The low-cost surface …
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The Biogeochemistry of Methane Isotopologues in Marine and Lacustrine Sediments
… situ concentration of methane based on ratios of dissolved gases, and its comparison to four other methane quantification methods for surface sediments from marine cold seeps. The findings from this research contribute to ongoing efforts to understand the sedimentary carbon cycle and microbial …
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