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 24 for “"iron reduction"”.
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Iron Reduction in Soot
Ferrous iron (Fe(II)) has been implicated as one contributor in the generation of reactive oxygen species (ROS) from ambient particles emitted during the incomplete combustion of fossil and biomass fuels. Although ROS are known to induce unhealthy oxidative stress in cellular systems, the …
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Effect of Carbonaceous Nanoparticles on Naturally Occurring Iron Reduction by Carboxylates
… due to the detrimental effects on health, environment and climate; yet many underlying mechanisms of PM reactivity are still not well understood. In the current study, the effect of carbonaceous nanoparticles (CNPs), contained within ultrafine PM (particle diameter ≤ 100 nm), is investigated …
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NITROGEN METABOLISM AND IRON REDUCTION IN AQUASPIRILLUM MAGNETOTACTICUM (NITRATE, FIXATION, MAGNETIC BACTERIUM)
… microaerobic conditions. Products of NO(,3)('-) reduction by growing cells included NH(,4)('+), N(,2)O, NO, and N(,2) but not NO(,2)('-) or NH(,2)OH. The inclusion of NH(,4)('+) in growth medium prevented NO(,3)('-) reduction to NH(,4)('+) but not to N(,2)O or N(,2). Cells consumed O(,2) while …
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Numerical Modeling Of Dissimilatory Iron Reduction In Sediments At A Field Site
… scaled-dependent parameters for the biological reduction of hematite. Three possible rate formulations were proposed to describe the bioreduction rate of hematite, and two kinds of simulation were conducted to validate the formulations and parameters with both batch and column experimental data: …
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Iron reduction mediated increases in carbon oxidation and phosphorus precipitation in on-site wastewater systems
… effects on microbes in natural aqueous environments. We proposed a novel technique to anaerobic onsite wastewater by leveraging iron reduction to oxidize more carbon and precipitate phosphorus with reduced iron as vivianite. We used carbon-14 radiolabeled acetate, lactate, propionate, …
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Geochemical Controls on Mercury Methylation in Backwaters of a Gulf Coastal Plain River System, Implications for Water Column Processes
… of 74.0-142.7 micrograms/liter indicate sulfate reduction was occurring in the bottom water or at the sediment-water interface, yet filtered and particulate methyl mercury concentrations were not significantly correlated to sulfide concentrations. The occurrence of sulfides in the bottom-water is …
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Microbial and Chemical Zonation and Mineral Weathering in the Middendorf Aquifer, South Carolina
… activity, most notably aerobic respiration and iron reduction, lead to a net generation of acid as CO2, but reaction of groundwater with minerals in the aquifer consumes the acid, driving up pH and controlling the evolution of the groundwater's major ion chemistry. The thermodynamic energy …
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Transcriptional Regulation of Shewanella oneidensis Using Native TMAO-Inducible Promoters in a Plasmid-Free System
… of the synthetic system increased extracellular iron reduction, an indicator of increased EET activity. My work expands the genetic components that can be used to engineer S. oneidensis for use in biotechnological applications.
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Organic matter remineralization in the sediment of two acid mine drainage lakes
Acid mine drainage is a significant environmental problem throughout the world. At Rocky Forks Conservation Area near Columbia, MO numerous lakes have formed from old coal mining pits. Most of these lakes have a pH near 7, presumably buffered by the limestone bedrock except one, nicknamed Red Lake, …
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Removal of organic contaminants from aqueous systems
… For NB, this study focusses on removal via both iron reduction and adsorption, while removal of the other three compounds is focussed purely on adsorption. The results demonstrate NB degradation using iron powder produces AN, with the rate decreasing under basic conditions, due to corrosive …
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Roles for multiple iron acquisition systems in Vibrio cholerae
… is a highly successful human pathogen and environmental organism. To thrive in these diverse environments, it must encode the tools necessary to acquire essential nutrients such as iron. A number of V. cholerae iron acquisition systems have been identified, and altogether are necessary for …
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The Influence of Hydrogeomorphology, Soil Redox Conditions, and Salinity on the Spatial Zoning of Saltgrass, Salt Rush, and Cattails in Scotts Creek Marsh, Swanton Pacific Ranch, CA
… to the test the effectiveness of Indicator of Reduction in Soil (IRIS) tubes to indicate the reduction of S. The study examined the following parameters from April 6 to July 21, 2013: (i) the HGM of Scotts Creek Marsh, (ii) soil oxidation and reduction (redox) conditions, (iii) salinity, and …
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Leaching from High Capacity Arsenic-Bearing Solid Residuals under Landfill Conditions
… This work focuses on testing different arsenic iron- oxide and non- iron- based sorbents, likely to be used for arsenic removal, and assessing the long term behavior of these sorbents under landfill conditions. Our results indicate that microbial processes play a major role in the mobilization …
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Basalt alteration and its consequences
… of basalt alteration in three distinct Earth environments using reactive transport modelling coupled to geochemical analyses. The weathering of basalt creates unique chemical environments that can drive carbonate mineral precipitation and other secondary mineral formation. The extreme reactivity …
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Evaluation of metal dusting of nickel-chromium-iron based alloys in a laboratory environment
The deposition of carbon from a carbon-rich environment onto structural materials is prevalent in petrochemical and chemical industries such as in the production of syngas, iron reduction plants, petroleum refineries, carbon dioxide cooled nuclear plants, fuel cells using molten salts and …
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Iron and reactive oxygen in wheat-pathogen interactions
Iron is an essential component of various proteins and pigments for both plants and pathogenic fungi. However, redox cycling between the ferric and ferrous forms of iron can also catalyse the production of dangerous free radicals and iron homeostasis is therefore tightly regulated. During pathogen …
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Investigating ferric ion production and consumption trends in a simulated e-waste bioleaching environment for maximum metal dissolution efficiency
… activity; and ferric ion consumption through the reduction of metals leading to metal dissolution. The ferric ion consumption and production rates depend on each other and other factors. The metal dissolution through ferric iron reduction is a function of ferric iron concentration, affected by how …
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Development of the Urban Wetland Filter for Managing Phosphorus in Stormwater
… nutrients in stormwater is a substantial environmental and economic problem in the U.S. Phosphorus (P) is often the limiting nutrient for harmful algal blooms and the best target to prevent degradation. Natural treatment strategies such as constructed wetlands (CW) demonstrate effective and …
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High-temperature defect engineering for silicon solar cells : predictive process simulation and synchrotron-based microcharacterization
Efficiency is a major lever for cost reduction in crystalline silicon solar cells, which dominate the photovoltaics market but cannot yet compete subsidy-free in most areas. Iron impurities are a key performance-limiting defect present in commercial and precommercial silicon solar cell materials, …
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Trace Element Cycling during Iron(II)-activated Recrystallization of Iron(III) Oxide Minerals
Biogeochemical iron cycling initiates secondary abiotic reactions between aqueous Fe(II) and Fe(III) oxide minerals, which results in dynamic recrystallization via simultaneous Fe(II) oxidative adsorption and Fe(III) reductive dissolution. Fe(III) oxide minerals are abundant in soils, sediments, …
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