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Full-Text Articles in Physical Sciences and Mathematics
A Study Of The Anthropogenic Impact In Farmington Bay Through Isotopic And Elemental Analysis, Nathan Vaun Gunnell
A Study Of The Anthropogenic Impact In Farmington Bay Through Isotopic And Elemental Analysis, Nathan Vaun Gunnell
Theses and Dissertations
The influence of human activity on surrounding environments is an important field of research. With respect to aquatic settings, lacustrine deposits provide excellent proxies of environmental change since the sediment accumulates at a relatively constant rate, recording environmental change. This study employs isotopic, mineral, and chemical records from Farmington Bay freeze cores, in particular δ13C, δ15N, and 210Pb isotopes as well as phosphorus level fluctuation and trace metal analysis. In particular, 210Pb isotopes permit estimation of the age of sediment with depth and δ15N, δ13C, and concentration of P provides a record of changing nutrient sources and level of eutrophication. …
Immobilization Of Copper Nanoparticles Onto Various Supports Applications In Catalysis, Anh Hoang Tu Nguyen Sorenson
Immobilization Of Copper Nanoparticles Onto Various Supports Applications In Catalysis, Anh Hoang Tu Nguyen Sorenson
Theses and Dissertations
Copper-based materials are one of the most promising catalysts for performing transformations of important organic compounds in both academic and industrial operations. However, it is challenging to consistently synthesize highly active and stable copper species as heterogeneous catalysts due to their relatively high surface energy. As a result, agglomeration usually occurs, which limits the catalytic activities of the copper species. The work presented in this dissertation shows different synthetic strategies for obtaining active and stable copper-based materials by modifying chemical/physical properties of copper nanoparticles (NPs). Emphasis is placed on discussing specific catalytic systems, including carbon-supported catalysts (monometallic and bimetallic copper-based …
Regional Drivers Of Organic Carbon Age In Lotic Systems Of The Conterminous United States, Kaycee Faunce
Regional Drivers Of Organic Carbon Age In Lotic Systems Of The Conterminous United States, Kaycee Faunce
Theses and Dissertations
Rivers play a critical role in global carbon (C) budgets despite their comparatively small surface area. A significant portion of the terrestrial C that they receive is transformed, re-mineralized, or stored during transit to the ocean. Radiocarbon (∆14C) data show that a fraction of riverine organic C (OC) has been pre-aged in the terrestrial environment. Lateral export of carbon from these aged pools may contribute to atmospheric carbon dioxide emissions through microbial and photochemical oxidation. However, little is known about the regional climatic, anthropogenic, and landscape factors that promote the mobilization of aged OC to rivers. This study …