Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- Department of Earth and Environmental Sciences (162)
- Environmental Science (32)
- Department of Mechanical and Materials Engineering (30)
- Geophysics (14)
- Geology (12)
-
- Ohio (9)
- Biogeochemistry (8)
- Earth (8)
- Ecology (8)
- Mechanical Engineering (8)
- Sediment (7)
- Methylmercury (6)
- Nitrogen (6)
- Permeability (6)
- Biology (5)
- Environmental Geology (5)
- Geological (5)
- Geophysical (5)
- Limnology (5)
- Paleontology (5)
- Algae (4)
- Denitrification (4)
- Eutrophication (4)
- Geochemistry (4)
- Hydrology (4)
- Mercury (4)
- Nitrate (4)
- Nitrification (4)
- Periphyton (4)
- Phosphorus (4)
Articles 1 - 30 of 192
Full-Text Articles in Physical Sciences and Mathematics
Mercury Methylation In Oxic Sub-Polar Marine Regions Linked With Nitrification, Marissa Collins Despins
Mercury Methylation In Oxic Sub-Polar Marine Regions Linked With Nitrification, Marissa Collins Despins
Browse all Theses and Dissertations
Methylmercury (MeHg) is a neurotoxin that bioaccumulates to potentially harmful concentrations in Arctic marine wildlife and in those that consume them. Monitoring and modeling MeHg bioaccumulation and biogeochemical cycling in the ocean requires understanding of the mechanisms behind net mercury (Hg) methylation. The key functional gene for Hg methylation, hgcAB, is widely distributed throughout ocean basins and spans multiple microbial phyla. While multiple microbially-mediated anaerobic pathways for Hg methylation are known, in the ocean, the majority of hgcA homologs have been found in oxic subsurface waters, in contrast to other ecosystems. In particular, microaerophilic Nitrospina, a genera of nitrite-oxidizing bacteria …
Has Winter Weather In Southwest Ohio Been Affected By The El Niño Southern Oscillation, The North Atlantic Oscillation, The Pacific Decadal Oscillation, And The Atlantic Multidecadal Oscillation?, John A. Blue
Browse all Theses and Dissertations
Winter temperature and precipitation in Southwest Ohio over the last century were examined for anomalies attributable to teleconnections with large-scale atmospheric perturbations caused by the El Niño Southern Oscillation (ENSO), the North Atlantic Oscillation (NAO), the Pacific Decadal Oscillation (PDO), and the Atlantic Multidecadal Oscillation (AMO). The record of temperature gives evidence of a teleconnection with the NAO, ENSO, and PDO, with the strongest link being for phases of the NAO. Most winters during positive NAO phases had mean monthly temperature warmer than the century long mean, and the majority of negative NAO phase winters had colder temperatures. The difference …
Bedrock Anisotropy At Sycamore Farms: An Investigation Using Azimuthal Resistivity And Electromagnetic Induction, Cody M. Kessler
Bedrock Anisotropy At Sycamore Farms: An Investigation Using Azimuthal Resistivity And Electromagnetic Induction, Cody M. Kessler
Browse all Theses and Dissertations
Azimuthal resistivity surveys coupled with an electromagnetic survey were completed at Sycamore Farms with the goal of investigating bedrock fracturing at the site. Previous work on this subject matter was completed at the site using similar geophysical tools, however, this study utilizes a unique method of azimuthal resistivity and higher resolution electromagnetic data. 72 azimuthal surveys were completed, and the electromagnetic survey covered all fields in which azimuthal surveys were completed. The results from the two methods were compared to identify zones of bedrock fracturing. Although correlation between the two data sets was limited it was found that the electromagnetic …
Mercury Concentrations And Mercury Methylation Along The Freshwater To Marine Continuum, Lindsay D. Starr
Mercury Concentrations And Mercury Methylation Along The Freshwater To Marine Continuum, Lindsay D. Starr
Browse all Theses and Dissertations
Mercury (Hg) is a neurotoxin that can have detrimental impacts on the human nervous system and on brain development in infants. Methylmercury (MeHg) is the most toxic form of Hg and can concentrate to potentially harmful levels in higher levels of marine food webs. Production of MeHg in oxic water columns is poorly understood due to lack of knowledge of the mechanisms of formation and distribution. Recent work has reported widespread, putative Hg methylation genes in nitrite oxidizers, but any relationship with nitrifiers is unknown. This work focuses on Hg water column distribution, speciation, and methylation. The aims of this …
Evaluating Energy-Based Trait Shifts And Population Level Impacts Of Big Brown Bats (Eptesicus Fuscus) With Long-Term Exposure To Pseudogymnoascus Destructans, Molly C. Simonis
Evaluating Energy-Based Trait Shifts And Population Level Impacts Of Big Brown Bats (Eptesicus Fuscus) With Long-Term Exposure To Pseudogymnoascus Destructans, Molly C. Simonis
Browse all Theses and Dissertations
Disturbances in environment can lead to a wide range of host physiological responses. These responses can either allow hosts to adjust to new conditions in their environment or can reduce their survival, and can subsequently cause host traits to shift. Small mammals are particularly vulnerable to stochastic disturbances, like a pathogen introduction, because of their high energy demands. Studies examining host responses to pathogens often focus on species highly susceptible to infection that typically have high mortality rates, leading to a gap in understanding the responses of less susceptible species. My dissertation evaluates the energy balance of Eptesicus fuscus (big …
Vertebrate Assemblages Of The Skelley Limestone (Conemaugh Group : Carboniferous, Gzhelian) In Noble And Muskingum Counties, Ohio, Daniel Austin Cline
Vertebrate Assemblages Of The Skelley Limestone (Conemaugh Group : Carboniferous, Gzhelian) In Noble And Muskingum Counties, Ohio, Daniel Austin Cline
Browse all Theses and Dissertations
Three outcrops of the Gzhelian-aged Skelley Limestone (Casselman Formation, Conemaugh Group) were explored for vertebrate macrofossils and vertebrate microremains. The purpose of this exploration was to construct a better ecological history of the marine communities in the Late Pennsylvanian of eastern Ohio. Bulk limestone samples were collected, washed with acid, sieved and the resulting residues produced 21 distinct taxa of near-shore marine vertebrates. Osteichthyans were represented by an unknown palaeonisciform, an unknown platysomid, and an unknown palaeoniscoid. Holocephalians were represented by symmoriforms, helodontiforms, cochliodontiforms, and petalodontiforms. Elasmobranch groups included ctenacanthiforms and euselachians which contained representatives of hybodontiforms, protacrodontiforms, and neoselachians. …
Development Of A Computer Model To Simulate Battery Performance For Use In Renewable Energy Simulations, Arjun Sundararajan
Development Of A Computer Model To Simulate Battery Performance For Use In Renewable Energy Simulations, Arjun Sundararajan
Browse all Theses and Dissertations
Renewable and clean energy has been the driving force behind the booming storage industry. The need for producing energy from clean and quickly replenishable energy sources has never been as high as it is now. However, renewable energy only supplies a little over a quarter of the world’s electricity needs and much less of the world’s total energy requirements. One reason is the intermittent nature of renewable energy. Inexpensive and convenient storage technologies are required to solve this issue. It is believed that batteries offer the most viable solution to conquer the problem of renewable energy intermittency. To aid the …
Analysis Of Amur Honeysuckle Stem Density As A Function Of Spatial Clustering, Horizontal Distance From Streams, Trails, And Elevation In Riparian Forests, Greene County, Ohio, Greg Michael Grierson Jr.
Analysis Of Amur Honeysuckle Stem Density As A Function Of Spatial Clustering, Horizontal Distance From Streams, Trails, And Elevation In Riparian Forests, Greene County, Ohio, Greg Michael Grierson Jr.
Browse all Theses and Dissertations
The non-native invasive shrub Amur honeysuckle, Lonicera maackii (Rupr.) Herder (Gorchov and Trisel, 2003), is one of the most prolific invasive plant species across Midwestern and Northeastern landscapes of the United States. The locations of 2,095 individual Amur honeysuckle stems were geolocated using handheld GPS units in the understory of mixed growth forests at two study sites located approximately 5 km apart in northwestern Greene County, OH. Each site has undergone different levels of anthropogenic disturbance through time. The stem position data was used to measure the spatial clumping distribution and the density of Amur honeysuckle. The spatial clumping of …
North American Freshwater Snails As Paleoecologic Proxies In Crystal Lake, Medway, Ohio, Jaclyn R. Manker
North American Freshwater Snails As Paleoecologic Proxies In Crystal Lake, Medway, Ohio, Jaclyn R. Manker
Browse all Theses and Dissertations
This study combines various paleoecological proxies found within a sediment core extracted from Crystal Lake, Medway, Ohio in order to assess the lake’s sensitivity to past climate changes and how that may have affected lake water levels. Crystal Lake is a natural kettle lake formed at the end of the Wisconsin glaciation. It is now surrounded by approximately 500 residential homes and is privately owned by the HOA of Crystal Lake. A sediment core was extracted from Crystal Lake in 2007 and has been carbon dated to 18000 years before present, indicating that it contains a complete sedimentary history from …
Power Scaling Of Ice Floe Sizes In The Weddell Sea, Southern Ocean, Tristan J. Coffey
Power Scaling Of Ice Floe Sizes In The Weddell Sea, Southern Ocean, Tristan J. Coffey
Browse all Theses and Dissertations
The cumulative number versus floe area distribution of seasonal ice floes from four satellite images covering the Summer season (November - February) in the Weddell Sea Antarctica during the summer breakup and melting is fit by two scale-invariant power scaling regimes for the floe areas ranging from 7 to 20 x 108 m2. Scaling exponents, β, for larger floe areas range from -1.5 to -1.7 with an average of -1.6 for floe areas ranging from 6 x 106 to 55 x 107 m2. Scaling exponents, β, for smaller floe areas range from -0.8 to -0.9 with an average of -0.85 …
Effect Of Cloud Cover On Optimum Orientations Of Fixed Solar Panels For Maximum Yearly Energy Collection, Prethew Prasad
Effect Of Cloud Cover On Optimum Orientations Of Fixed Solar Panels For Maximum Yearly Energy Collection, Prethew Prasad
Browse all Theses and Dissertations
The amount of cloud cover present in the sky is a significant factor when determining the solar radiation impinging on a solar panel. The optimum tilt required to achieve maximum energy impingement on a surface is also influenced by the amount of cloud cover. This work presents a method for determining the optimum tilt angle for a fixed solar panel when a set amount of cloud cover is present in the sky. Fixed tilt angles that have the most incident solar energy over the course of a year as a function of cloud cover, latitude, and azimuthal angle orientation are …
Sediment Nutrient Dynamics In Fondriest Agricultural Settling Pond, Marie Grace Bezold
Sediment Nutrient Dynamics In Fondriest Agricultural Settling Pond, Marie Grace Bezold
Browse all Theses and Dissertations
Excess loading of nitrogen (N) and phosphorus (P) is a serious global problem and has numerous negative impacts on water quality of aquatic ecosystems including eutrophication, harmful algal blooms, and hypoxia. Anthropogenic activities (such as the Haber-Bosch process, burning of fossil fuels, sewage treatment, and manure reuse) have led to excess N loading to aquatic systems. Sediment N dynamics were examined from Oct 2019 – Oct 2020 in an agricultural settling pond connected to a constructed wetland adjacent to an agricultural field. Intact sediment cores were amended with 15N for continuous-flow incubations to measure denitrification and N fixation rates, as …
Utilizing Rotational Energy In Wind Turbine Blades With The Flywheel Mechanism And Predicting The Power Output By Neural Networking, Anamika Mishra
Utilizing Rotational Energy In Wind Turbine Blades With The Flywheel Mechanism And Predicting The Power Output By Neural Networking, Anamika Mishra
Browse all Theses and Dissertations
As we expand and innovate for better and safer living, there will always be a need for new energy sources. By replacing fossil fuels, renewable energy is becoming a viable option for primary power generation. That is why researchers are turning their attention to renewable energy sources and ways of making the most of them. WIND ENERGY is a promising renewable and clean energy source harvested from the wind which is plentiful on the planet. We already have the technology to harvest it, but the efficiency and power output are not optimal. In this thesis, to enhance the energy harvesting …
Pre-Stack Seismic Inversion And Amplitude Variation With Offset (Avo) Attributes As Hydrocarbon Indicators In Carbonate Rocks: A Case Study From The Illinois Basin, Jacob T. Murchek
Browse all Theses and Dissertations
Amplitude anomalies in pre-stack seismic data have widely been used in the oil and gas industry as a risk analysis tool when exploring for hydrocarbons. AVO analysis is most often applied to poorly consolidated Tertiary rocks due to the compressibility of these strata when natural gas and porosity are present. In contrast, well-lithified carbonate rocks are less prone to producing a pre-stack amplitude response due to the rigidity of their frame. Pre-stack seismic data of a 2-D seismic profile were conditioned and interpreted to identify amplitude variation with offset (AVO) attributes corresponding to the presence of hydrocarbons within the North …
Computer Modeling Of Solar Thermal System With Underground Storage Tank For Space Heating, Mohammad Yousef Mousa Naser
Computer Modeling Of Solar Thermal System With Underground Storage Tank For Space Heating, Mohammad Yousef Mousa Naser
Browse all Theses and Dissertations
Space heating is required in almost every dwelling across the country for different periods of time. The thermal energy needed to meet a heating demand can be supplied using different conventional and/or renewable technologies. Solar energy is one example of a renewable resource that can be used for supplying heating needs. It can be utilized either by using photovoltaic panels to generate electricity, that in turn can be used to operate heaters, or by using solar thermal panels. Solar thermal panels obtain higher operating efficiencies than photovoltaic panels, but solar energy for heating purposes suffers from a mismatch between supply …
Diversity And Function Of Algal Biofilms In The Laurentian Great Lakes, Leon R. Katona
Diversity And Function Of Algal Biofilms In The Laurentian Great Lakes, Leon R. Katona
Browse all Theses and Dissertations
Attached algae are ubiquitous components of lake benthic habitats wherever sufficient light reaches submerged surfaces. Attached algae interact with heterotrophic bacteria and fungi to form complex biofilms (“periphyton”) that provide a nutritious food source for consumers and influence biogeochemical cycling by regulating redox potential at the sediment-water interface. Despite their ecological importance, there are limited data on the role of periphyton in the Laurentian Great Lakes. I quantified wave exposure and light availability in rocky nearshore habitats in Lake Erie and Lake Huron. Periphyton biomass and productivity in nearshore Lake Erie was very high while algal biomass and productivity in …
Sediment-Water Fluxes Of Phosphorus And Trace Metals In The Maumee River, Northwest Ohio, Emily L. Holliday
Sediment-Water Fluxes Of Phosphorus And Trace Metals In The Maumee River, Northwest Ohio, Emily L. Holliday
Browse all Theses and Dissertations
Excess phosphorus (P) and nitrogen (N) in the western basin of Lake Erie drive annual cyanobacteria blooms and associated hypoxia events. The Maumee River inputs ~5% of the water load into the western basin and ~50% of annual P loadings. I quantified seasonal variability of net P and metals fluxes from sediments in the Maumee River at four stations from Defiance, Ohio, to Maumee Bay. Upriver sediments were, on average, a total and filtered P sink throughout the year (−19 ± 7 and −6 ± 3, respectively; all fluxes represent `net flux’ reported in µmol m−2 h−1). At the river …
Internal Loading Of Nitrogen (N) And Phosphorus (P), Reduced N Forms, And Periodic Mixing Support Cyanobacterial Harmful Algal Blooms (Habs) In Shallow, Eutrophic Honeoye Lake (New York, Usa), Justin Adam Myers
Browse all Theses and Dissertations
Cyanobacteria are important primary producers, but large cyanobacterial harmful algal blooms (HABs) have many negative ecological and health impacts and are becoming increasingly common. Honeoye Lake (New York, USA) is a shallow, eutrophic lake characterized by increasingly frequent HABs. Nitrogen (N) and phosphorus (P) loads often drive HABs in lakes, and sediment processes can contribute to N removal (e.g., denitrification) or loading (e.g., N fixation, remineralization). Sediment cores and lake water were collected during May–October (2016–2018) at two sites and incubated with no amendments (controls) or 15N stable isotopes to measure sediment nutrient fluxes and N cycling dynamics in Honeoye …
Grain-Size And Permeability Of Sediments Within The Hyporheic Zone At The Theis Environmental Monitoring And Modeling Site, Great Miami River And Buried Valley Aquifer, Southwest Ohio, Usa, Timothy Wayne Cornett
Grain-Size And Permeability Of Sediments Within The Hyporheic Zone At The Theis Environmental Monitoring And Modeling Site, Great Miami River And Buried Valley Aquifer, Southwest Ohio, Usa, Timothy Wayne Cornett
Browse all Theses and Dissertations
The Theis Environmental Monitoring and Modeling Site is a field research facility, located on the Great Miami River in southwest Ohio, dedicated to the study of hyporheic zone processes. The site is underlain by an aquifer on the order of 21 meters thick, comprised of fluvial deposits. The permeability of the aquifer sediments was quantified both from one large scale hydraulic test (~100 m radial distance) and from grain-size analysis of 119 small-scale core samples (~20 cm length each). The permeability determined from the large-scale hydraulic test is 98.9 Darcies. The test also gave a value for specific yield of …
Utilizing Rotational Energy In Wind Turbine Blades With The Flywheel Mechanism And Predicting The Power Output By Neural Networking, Anamika Mishra
Utilizing Rotational Energy In Wind Turbine Blades With The Flywheel Mechanism And Predicting The Power Output By Neural Networking, Anamika Mishra
Browse all Theses and Dissertations
As we expand and innovate for better and safer living, there will always be a need for new energy sources. By replacing fossil fuels, renewable energy is becoming a viable option for primary power generation. That is why researchers are turning their attention to renewable energy sources and ways of making the most of them. WIND ENERGY is a promising renewable and clean energy source harvested from the wind which is plentiful on the planet. We already have the technology to harvest it, but the efficiency and power output are not optimal. In this thesis, to enhance the energy harvesting …
Grain-Size And Permeability Of Sediments Within The Hyporheic Zone At The Theis Environmental Monitoring And Modeling Site, Great Miami River And Buried Valley Aquifer, Southwest Ohio, Usa, Timothy Wayne Cornett
Grain-Size And Permeability Of Sediments Within The Hyporheic Zone At The Theis Environmental Monitoring And Modeling Site, Great Miami River And Buried Valley Aquifer, Southwest Ohio, Usa, Timothy Wayne Cornett
Browse all Theses and Dissertations
The Theis Environmental Monitoring and Modeling Site is a field research facility, located on the Great Miami River in southwest Ohio, dedicated to the study of hyporheic zone processes. The site is underlain by an aquifer on the order of 21 meters thick, comprised of fluvial deposits. The permeability of the aquifer sediments was quantified both from one large scale hydraulic test (~100 m radial distance) and from grain-size analysis of 119 small-scale core samples (~20 cm length each). The permeability determined from the large-scale hydraulic test is 98.9 Darcies. The test also gave a value for specific yield of …
Anthrax Event Detection: Analysis Of Public Opinion Using Twitter During Anthrax Scares, The Mueller Investigation, And North Korean Threats, Michele E. Miller
Anthrax Event Detection: Analysis Of Public Opinion Using Twitter During Anthrax Scares, The Mueller Investigation, And North Korean Threats, Michele E. Miller
Browse all Theses and Dissertations
When people allow fear to drive their decision making, they often make decisions that do more harm than good. Examples of this include stocking up on ciprofloxacin, flooding doctors’ offices and buying black market antibiotics after the anthrax attacks of 2001. Therefore, it is important to be able to address what people are saying when another anthrax attack occurs. Supervised and unsupervised machine learning methodologies can be utilized to detect an event, classify the tweets by event, and to determine the main topics of discussion. Over the period of data collection, twenty events were detected. Three of these events concerned …
The Fate Of Anthropogenic Nitrogen Along Hydrologic Continuums: Patterns Of Transformation And Recycling In A Eutrophic Lake And Coastal Marine Sediments, Daniel K. Hoffman
The Fate Of Anthropogenic Nitrogen Along Hydrologic Continuums: Patterns Of Transformation And Recycling In A Eutrophic Lake And Coastal Marine Sediments, Daniel K. Hoffman
Browse all Theses and Dissertations
Eutrophication of aquatic systems can have cascading effects along hydrological continua from watersheds to coasts that result in impaired ecosystem health. In freshwater systems, blooms of toxic, non-nitrogen (N) fixing cyanobacteria (cyanoHABs), such as Microcystis, proliferate due to external loading of chemically reduced forms of N (e.g., ammonium (NH4+) and urea), which promote growth and toxin production. In coastal marine systems, nutrient loading can promote harmful algae blooms and threaten vulnerable, native vegetation, such as seagrasses, which provide valuable ecosystem services but are under threat globally from anthropogenic stressors. This dissertation focuses on NH4+ cycling in the water column of …
Genetic Analysis Of Snow Leopard Population Employing Next Generation Sequencing For Its Improved Conservation And Management, Safia Janjua
Genetic Analysis Of Snow Leopard Population Employing Next Generation Sequencing For Its Improved Conservation And Management, Safia Janjua
Browse all Theses and Dissertations
Snow leopards (Panthera uncia) are an enigmatic, high-altitude species whose challenging habitat, low population densities and patchy distribution have presented challenges for scientists studying its biology, population structure, and genetics. To address these important ecological, conservation, and evolutionary questions, scientists are tailoring laboratory and computational methods to better extract the information from non-invasive samples, only available source of DNA for this species. These samples with very low quantity and quality of DNA, present unique methodological challenges. ddRAD-seq, one of next generation sequencing method is used here to develop reference sequence library for snow leopard using five blood samples from Mongolian …
The Hydrostatics And Hydrodynamics Of Prominent Heteromorph Ammonoid Morphotypes And The Functional Morphology Of Ammonitic Septa, David Joseph Peterman
The Hydrostatics And Hydrodynamics Of Prominent Heteromorph Ammonoid Morphotypes And The Functional Morphology Of Ammonitic Septa, David Joseph Peterman
Browse all Theses and Dissertations
Ammonoid cephalopods have chambered shells that regulated buoyancy. The morphology of their shells strongly influenced the physical properties acting on these animals during life. Heteromorph ammonoids, which undergo changes in coiling throughout ontogeny, are the focus of this dissertation. The biomechanics of these cephalopods are investigated in a framework involving functional morphology, paleoecology, and possible modes of life. Constructional constraints were investigated for the marginally-corrugated septal walls within the chambered ammonoid shell. These constraints governed the positive relationship between septal complexity and terminal size. Furthermore, increased septal complexity facilitated liquid retention via surface tension. More complex septa would have increased …
Quantifying Contributions To The Variance Of Permeability And Porosity Within The Western Belt Sandstones Of The Cypress Formation, Illinois Basin, Nathaniel Frederick Dulaney
Quantifying Contributions To The Variance Of Permeability And Porosity Within The Western Belt Sandstones Of The Cypress Formation, Illinois Basin, Nathaniel Frederick Dulaney
Browse all Theses and Dissertations
One of the strategies for reducing the emission of the greenhouse gas carbon dioxide (CO2) and mitigating its accumulation into the Earth’s atmosphere is geologic sequestration (GSCO2). This process might be paired with enhanced oil recovery (EOR) within depleted oil reservoirs to provide an economic incentive for GSCO2. Heterogeneity within reservoirs (e.g. spatial differences in entry pressure, permeability, and porosity) can exert significant influence on the dynamics of fluid flow during EOR and GSCO2, and thus on the ultimate success of GSCO2-EOR. The Western Belt sandstones of the Cypress Formation in the Illinois Basin are candidate reservoirs for GSCO2-EOR. Heterogeneity …
Optimization Study Of A Combined Wind-Solar Farm For A Specified Demand, Venkat Siddhartha Rama
Optimization Study Of A Combined Wind-Solar Farm For A Specified Demand, Venkat Siddhartha Rama
Browse all Theses and Dissertations
At the present time, using wind and solar energy for producing electricity in the United States is becoming cost competitive. According to Lazard’s 2019 [36] levelized cost of energy (LCOE) analysis of a number of energy sources used for producing electricity in the United States, wind and solar are cheaper than natural gas and coal. While capital, maintenance, operation, and fuel costs are included in LCOE numbers, energy source intermittency is not. Intermittency is an important issue with wind and solar energy sources, but not with natural gas or coal energy sources. Combining wind and solar energy sources into one …
Computational Assessment Of Aortic Valve Function And Mechanics Under Hypertension, Saurav Kadel
Computational Assessment Of Aortic Valve Function And Mechanics Under Hypertension, Saurav Kadel
Browse all Theses and Dissertations
Calcific aortic valve disease (CAVD), the most common valvular heart disorder, is associated with complications such as stroke, heart attack, aortic aneurysm, left ventricular hypertrophy, and ultimately death. While hypertension has been identified as a major risk factor for CAVD, the mechanisms by which it may promote calcification are still unknown. Given the sensitivity of valvular tissue to mechanical stress alterations, the hemodynamic abnormalities linked to hypertension may play a role in the development of CAVD. Further, the effects of hypertension on the left ventricular functionality and coronary flow resistance remain largely uninvestigated. Hence, the objectives of this thesis were …
Degradation Of Trichloroethene By Radicals Produced By Oxygenation Of Various Reduced Iron Minerals, Jonathon Michael Deeter
Degradation Of Trichloroethene By Radicals Produced By Oxygenation Of Various Reduced Iron Minerals, Jonathon Michael Deeter
Browse all Theses and Dissertations
Fe(II)-containing minerals (often as oxides and sulfides) are commonly present in the shallow subsurface and aquifers. Recent studies have shown that Fe(II) can generate reactive oxygen species upon oxygenation. This bench-scale investigation examined the generation of radical species from [Fe(II)]-containing mineral phases when exposed to oxygen. The Fe(II)-minerals in this study were chemically-reduced hydrous ferric oxide (HFO) and goethite, magnetite, and mackinawite (FeS). This research demonstrated that trichloroethene (TCE) can rapidly degrade by radicals produced from Fe(II)-containing oxides if gaseous oxygen is introduced in reactors. In contrast, there was little or no TCE degradation from oxygenation of freshly-prepared ferrous sulfide …
Marine Vertebrate Communities From The Cisuralian Epoch (Permian Period) Of Central North America, Ryan C. Shell
Marine Vertebrate Communities From The Cisuralian Epoch (Permian Period) Of Central North America, Ryan C. Shell
Browse all Theses and Dissertations
Marine vertebrates from the Cisuralian Epoch early Permian Period) are rare in the global fossil record. In particular, species-rich faunas from individual localities are poorly represented, with single occurrence localities that do not fully capture faunal tends in marine vertebrate ecology across this interval. This dissertation helps to close this gap by reporting marine vertebrate fossils from five localities across central North America, containing four to 15 unequivocal vertebrate taxa, as well as a new single occurrence locality near the Carboniferous-Permian boundary. This survey includes representatives from the first three of the four Cisuralian faunal stages, and is the result …