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.
Results
Showing 1 to 11 of 11 for “"Sulfur cycle"”.
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Conceptual design of nuclear systems for hydrogen production
… electrolysis and a hybrid electrolysis-chemical sulfur cycle. Also addressed is the sensitivity of production and efficiency of these cycles to process conditions. For a desired hydrogen distribution pressure of 3MPa, high system pressures increase the efficiency of high temperature steam …
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Exploring the contributions of liquid-phase sulfur chemistry to the mass-independent sulfur fractionation of the Archean rock record
Archean sulfur mass-independent fractionation (S-MIF) has been widely recognized as one of the strongest indicators for the rise of atmospheric oxygen in the Early Proterozoic. A decade after its discovery, the wide-ranging implications of Archean sulfur MIF have been discussed extensively and …
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Carbon and sulfur isotopic constraints on Ediacaran biogeochemical processes, Huqf supergroups, Sultanate of Oman
… along with large perturbations to the carbon and sulfur cycles. Paleoenvironmental reconstruction used the carbon and sulfur isotopic composition of sedimentary minerals and organic matter, supplemented by geochemical and molecular biomarker proxies, of strata from the Huqf Supergroup, Sultanate …
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Mechanistic, sensitivity, and uncertainty studies of the atmospheric oxidation of dimethylsulfide
… make it an integral component in the atmospheric sulfur cycle. DMS is rapidly oxidized in the atmosphere by a complex gas-phase mechanism involving many species and reactions. The resulting oxidized sulfur-bearing products are hygroscopic and interact with aerosols through condensation and …
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Understanding the ocean carbon and sulfur cycles in the context of a variable ocean : a study of anthropogenic carbon storage and dimethylsulfide production in the Atlantic Ocean
… the emission of carbon dioxide. Ocean carbon and sulfur cycles have the potential to impact global climate directly and through feedback loops. Numerical modeling, field and laboratory studies are used to improve our mechanistic understanding of the impact of natural variability on carbon and …
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Understanding the ocean carbon and sulfur cycles in the context of a variable ocean : a study of anthropogenic carbon storage and dimethylsulfide production in the Atlantic Ocean
… the emission of carbon dioxide. Ocean carbon and sulfur cycles have the potential to impact global climate directly and through feedback loops. Numerical modeling, field and laboratory studies are used to improve our mechanistic understanding of the impact of natural variability on carbon and …
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Basalt alteration and its consequences
… consequences of this alteration for the global sulfur cycle; specifically with respect to anhydrite, which precipitates directly from seawater upon heating. I explore how past variations in ocean chemistry may have affected both the amount and the depth of anhydrite precipitation and speculate …
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Early evolution of environments and metabolism: insights from nitrogen, selenium and sulfur isotopes
… are tightly linked through global biogeochemical cycles, and this dissertation seeks to explore this linkage during the Precambrian with new strategies and geochemical techniques. The first chapter is the result of a group project in which we propose that multiple environments and processes were …
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The Biogeochemistry of Hydrogen Sulfide in the Open Ocean
… is a poorly quantified component of the global sulfur cycle. In seawater, its dissolved species (dissolved sulfide) can react with trace metals to form dissolved complexes and insoluble compounds. Therefore, the study of dissolved° sulfide in the open ocean can yield a better understanding of …
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Geochemical fractionation during melting of sulfide and sulfate bearing mantle lithologies
Earth’s surficial biogeochemical sulfur (S) cycle is connected to the deep sulfur cycle at convergent margins, where, crust and oceanic lithospheric mantle subducts beneath an overriding plate and transporting sulfur and other materials from the surface to the deep Earth. A part of the subducted …
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Magmatic volatiles at rifts and arcs: Sources and fractionation effects
… additional data (including carbon, oxygen ,and sulfur isotope compositions and assessment of sulfur behaviour in the magma system) from Oldoinyo Lengai that have not been published. Chapter 2 presents the first bulk gas and nitrogen isotope compositions from the Rungwe Volcanic Province, which …