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Full-Text Articles in Physical Sciences and Mathematics

Regulation Of Dissolved Arsenic Using Zero-Valent Iron With Gypsum And Sulfate Reducing Bacteria: Laboratory Microcosm And Column Studies, Ying Liu Sep 2018

Regulation Of Dissolved Arsenic Using Zero-Valent Iron With Gypsum And Sulfate Reducing Bacteria: Laboratory Microcosm And Column Studies, Ying Liu

Dissertations, Theses, and Capstone Projects

Bench scale microcosm incubation was first conducted in two stages to examine the removal of arsenic (As) by zero-valent iron (ZVI) in the presence of sulfate reducing bacteria, gypsum as well as organic substrates under anaerobic condition. About 98% of dissolved As was removed from solution within 20 days with concurrent decrease of dissolved sulfate and growth of bacterial population. Mineralogy analysis using SEM-EDS found the formation of iron sulfide and Fourier-transformed infrared (FTIR) spectroscopy analysis indicates that some As is associated with pyrite. The main iron corrosion product was found as ferrihydrite with traces of lepidocrocite. Sequential leaching shows …


Investigation Of Biogeochemical Mechanisms Of Greenhouse Gas Production In The Urban Hudson River Estuary, Brian Alan Brigham Sep 2018

Investigation Of Biogeochemical Mechanisms Of Greenhouse Gas Production In The Urban Hudson River Estuary, Brian Alan Brigham

Dissertations, Theses, and Capstone Projects

Coastal megacities deposit significant amounts of carbon (C), nitrogen (N) and other pollutants into surrounding waters. These inputs, including wastewater and surface water runoff, may affect estuarine and adjacent wetland biogeochemical cycles, microbial production and ultimately greenhouse gas (GHG) efflux. In many megacities pollutant loading is typically greatest after periods of precipitation when the volume of wastewater and storm water runoff exceeds local sanitation capacity, resulting in the discharge of raw sewage into adjacent waters. These combined sewage overflow (CSO) events have received considerable attention primarily due to their potential impact on human health and eutrophication. However, whether these events …


Quantifying The Effects Of Wind Regimes And Temperature On Surface Melt Over The Antarctic Peninsula (1982–2017) Through Modeling, Remote Sensing And In-Situ Data, Rajashree Datta Sep 2018

Quantifying The Effects Of Wind Regimes And Temperature On Surface Melt Over The Antarctic Peninsula (1982–2017) Through Modeling, Remote Sensing And In-Situ Data, Rajashree Datta

Dissertations, Theses, and Capstone Projects

Surface melting over the Antarctic Peninsula (AP) plays a crucial role for the stability of ice shelves and dynamics of grounded ice, hence modulating the mass balance in a region of the world which is particularly sensitive to increasing surface temperatures. Understanding the processes that drive melting using surface energy and mass balance models is fundamental to improving estimates of current and future surface melting and associated sea level rise through ice-shelf collapse. This is even more important in view of the specific challenges presented by how circulation patterns over the topographically-complex Antarctic Peninsula, especially foehn winds, impact surface melt. …


Aluminum-26: A Canonized Cosmochemical Conundrum, John Anton Feb 2018

Aluminum-26: A Canonized Cosmochemical Conundrum, John Anton

Dissertations, Theses, and Capstone Projects

This study focuses on the challenges associated with the historical development of the interpretative role of 26Al as both a thermodynamic contributor to planetesimal formation processes and an acutely precise chronometer of protoplanetary disk events. Conventional thought asserts that 26Mg concentrations can occur as isotopic excesses in meteorites and represent the daughter product of 26Al, a radioactive form of aluminum (t½ = ~0.73 ka). The greatest 26Mg concentrations generally occur in calcium aluminum inclusions (CAIs), meteoric constituents considered among the oldest known materials in the Solar System whose formation appear to predate the less refractory …


Evidence Of The 1762 Arakan And Prior Earthquakes In The Northern Sunda Subduction, Dhiman Ranjan Mondal Feb 2018

Evidence Of The 1762 Arakan And Prior Earthquakes In The Northern Sunda Subduction, Dhiman Ranjan Mondal

Dissertations, Theses, and Capstone Projects

The objective of this dissertation is to understand the seismic hazard associated with Arakan segment of the northern Sunda subduction along SE Bangladesh. In order to do that, it is necessary to document geologic evidence for the 1762 Arakan earthquake and prior events, to help estimate the recurrence interval (repeat time) for that earthquake. Historical records described that the 1762 earthquake caused extensive damage along the Arakan segment of the Sunda subduction system. But the geologic evidence for the earthquake farther north is necessary to better understand its associated seismic hazard to the densely populated nation of Bangladesh. This dissertation …


Convective Transport Of Tropical Marine Boundary Layer Species Into The Upper Troposphere And Relation To Species Lifetime: In Situ Measurements And Global Model Simulation, Sofia M. Chelpon Jan 2018

Convective Transport Of Tropical Marine Boundary Layer Species Into The Upper Troposphere And Relation To Species Lifetime: In Situ Measurements And Global Model Simulation, Sofia M. Chelpon

Dissertations and Theses

This study investigates the influence of tropical deep convection on distribution of trace gasses in the tropical upper troposphere (UT) using data from the Convective Transport of Active Species in the Tropics (CONTRAST) Experiment conducted over the tropical western Pacific during January and February of 2014. Fifty-five chemical species measured during the CONTRAST campaign are analyzed with lifetimes ranging from less than a day to several years. The vertical profiles of these species suggest that they fall into three main groups delineated by their lifetime: 1) very long-lived trace gases demonstrating a nearly constant vertical structure, 2) intermediate lifetime species …


Differentiation In Impact Melt Sheets As A Mechanism To Produce Evolved Magmas On Mars, Ari Koeppel Jan 2018

Differentiation In Impact Melt Sheets As A Mechanism To Produce Evolved Magmas On Mars, Ari Koeppel

Dissertations and Theses

Asteroid bombardment contributed to extensive melting and resurfacing of ancient (> 3 Ga) Mars, thereby influencing the early evolution of the Martian crust. However, information about how impact melting has altered Mars’ crustal petrology is limited. Evidence from some of the largest impact structures on Earth, such as Sudbury and Manicouagan, suggests that some impact melt sheets experience chemical differentiation. If these processes occur on Mars, we expect to observe differentiated igneous materials in some exhumed rock samples. Some rocks observed in Gale crater are enriched in alkalis (up to 14 wt% Na2O + K2O) and …