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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
181

Aquatic Habitat Mapping within the Obed Wild and Scenic River for Threatened and Endangered Species Habitat Delineation

Candlish, Joseph Ross 01 May 2010 (has links)
There is a need to define a more efficient and accurate approach to aquatic habitat mapping. Traditional approaches have focused on intense biological/non-biological sampling and observation analysis within specific and restrained scales. Therefore, an underwater video mapping system (UVMS) has been developed in efforts to identify federally protected aquatic species’ habitats within the Obed Wild and Scenic River (OBRI). The UVMS kayak apparatus provides georeferenced video footage correlated with GPS (global positioning systems) for GIS (geographic information systems) mapping applications. Based on its fluvial and geomorphological trends, OBRI was dissected quantitatively and integrated into databases for species-specific GIS habitat queries. Substrate type, depth, above water river characteristics (pool/riffle/run), and substrate embeddedness were extracted to access specific habitats. To better pinpoint optimal microhabitat locations, a physical habitat suitability model was developed to rank preferred habitat locales. Rankings were sequentially broken into five categories: optimal, sub-optimal, marginal, sub-marginal, and poor habitat criteria. Habitat suitability findings for the interested species habitats varied tremendously, favoring fish species. Spotfin chub, Erimonax monacha, optimal habitat was found to cover 22.14 km of river length within OBRI (30 % of OBRI’s spatial extent). The blackside dace, Phoxinus cumberlandensis, (38.9 km) and the duskytail darter, Etheostoma percnurum, (50.9 km) met optimal habitat conditions that yielded 51% and 69% of OBRI’s spatial extent, respectively. In general, optimal habitats for the six mussels were sporadically distributed and had low occurrences. Primarily, these mussel species prefer highly embedded areas with very specific depths and pool/riffle/run conditions. Cumberland elktoe, Alasmidonta atropurea, optimal habitat ranges spanned across 4.32 km (6% of OBRI’s spatial extent) with most of the habitat characteristics in OBRI being marginal. The purple bean, Villosa perpurpurea, optimal habitat was identified within 2.61 km of OBRI (3.5% of OBRI’s spatial extent). Most of the physical conditions of OBRI supplied poor to sub-marginal habitat for the purple bean, at least from a thalweg perspective. Only 385 m coincided with optimal habitat for the cumberland bean, Villosa trabalis, (0.5% of OBRI’s spatial extent) with most habitats in long sub-marginal reaches. Optimal habitats for the cumberlandian combshell, Epioblasma brevidens, the tan riffleshell, Epioblasma florentina walkeri, and the littlewing pearlymussel, Pegias fibula, were deficient, only occurring in 484 m, 276 m, and 252 m of OBRI, respectively (0.7%, 0.4%, and 0.3% of OBRI’s spatial extent). Marginal to sub-marginal habitats dominated the park for these three mussel species.
182

Agricultural Efficiency and the End of the Oil Age; Building a Future of Longevity

McHugh, Keith 13 May 2012 (has links)
This thesis uses an efficiency analysis of agricultural systems to assert that, in lieu of rising prices of fossil fuel, people need to come into more direct contact with their food systems. With a switch to smaller, more efficient farms that rely less on fossil fuel and are connected with the communities they supply for, we can avoid an energy crisis turning into a famine. These smaller-scale systems can help create self-contained, carbon-neutral communities.
183

The Study of Variations in the Properties of Biodiesel on Addition of Antioxidants

Kandala, Hiranmayee 01 August 2009 (has links)
This research studies variations in biodiesel upon addition of different concentrations of antioxidant and petrodiesel additives. Oxidation onset temperature, oxidation induction time, oxidative stability, thermal stability, crystallization onset temperature and moisture retention properties of the biodiesel, with and without antioxidants have been studied. Antioxidants like BHT, BHA, PrG, Vit E and Vit C were added to the biodiesel during the study. These samples were analyzed using the PDSC, TGA, DSC and TGA-SA instrumentation. The results of this research show an improvement in the OOT, OIT and Oxidative stability of biodiesel with the addition of antioxidants and by blending the biodiesel with different amounts of Petro-diesel. A significant improvement in oxidative stability of biodiesel has been observed with the addition of antioxidants and petrodiesel. There was no significant change noticed in the thermal stability, crystallization and the moisture retention properties of biodiesel. I hope that this research would help improving the oxidative stability of the biodiesel. The results from the analysis made in this study would also be helpful in designing a better antioxidant and aid in improving the present experimental methods for the OIT and thermal analysis.
184

Algal Biomass Accrual in Relation to Nutrient Availability along a Longitudinal Gradient in the Upper Green River, Kentucky

Penick, Mary Douglas 01 August 2010 (has links)
Nutrient limitation in aquatic ecosystems results from a deficiency in nitrogen or phosphorus levels relative to cellular growth needs. Nutrient limitation of freshwater systems is a function of biotic and abiotic factors. Biotic factors include vascular and nonvascular plant community composition. Abiotic factors include underlying bedrock and land-use activities (e.g. agriculture, septic systems). Nutrient availability directly affects growth, productivity, and community structure of primary producers. The purpose of this study was two-fold: (1) to assess the relationship between ambient algal biomass. and in-stream nutrient levels along the longitudinal course of a river through a transition from weak to well-developed underlying karst bedrock, and (2) experimentally assess if periphyton was nitrogen or phosphorous limited between weak and well-developed karst sites. Sestonic and filamentous biomass (= chlorophyll-a) levels increased monthly along the longitudinal gradient. In contrast, periphyton biomass levels increased minimally monthly and displayed no longitudinal pattern. Nitrate and soluble reactive phosphorus levels exhibited distinct longitudinal increases, whereas total phosphorous displayed minimal change and ammonia levels decreased in the downstream direction. Total nitrogen (TN) levels increased upstream but decreased sharply in the well-developed downstream karst sites. The nutrient limitation assays revealed that the highest periphyton levels were with N + P treatments at the most upstream sites. Overall, in Kentucky's Green River algal biomass accrual appears to be mainly P-limited but likely also by TN availability during late summer.
185

Development and assessment of environmental indicators for mobile source impacts on emissions, air quality, exposure and health outcomes.

Pachon Quinche, Jorge Eduardo 18 August 2011 (has links)
Environmental indicators were developed and evaluated to assess the impact of mobile sources on emissions, air quality, exposure and health. Different levels of indicators are discussed, from single species to multipollutant indicators. Carbon monoxide (CO), Nitrogen oxides (NOx) and elemental carbon (EC) were chosen as indicators of mobile sources because emissions of these pollutants are largely attributed to mobile sources and ambient concentrations have a close response to the change in mobile source emissions. These pollutants were used in the construction of the integrated mobile source indicators (IMSI). The IMSI have larger spatial representativeness and stronger associations with cardiovascular diseases (CVD) than single pollutants. The use of IMSI in epidemiologic modeling constitutes an alternative approach to assess the health impact of pollutant mixtures and can provide support for the setting of multipollutant air quality standards. The human health benefits of reducing mobile sources emissions were more consistent using multipollutant indicators. Indicator values and uncertainties, in the form of indicator sets, are presented with their associated outcomes and attributes to be useful for policy makers who are interested not only in the value of the indicators, but also in their associated uncertainties and their applicability at other times and other regions.
186

Aquatic Habitat Mapping within the Obed Wild and Scenic River for Threatened and Endangered Species Habitat Delineation

Candlish, Joseph Ross 01 May 2010 (has links)
There is a need to define a more efficient and accurate approach to aquatic habitat mapping. Traditional approaches have focused on intense biological/non-biological sampling and observation analysis within specific and restrained scales. Therefore, an underwater video mapping system (UVMS) has been developed in efforts to identify federally protected aquatic species’ habitats within the Obed Wild and Scenic River (OBRI). The UVMS kayak apparatus provides georeferenced video footage correlated with GPS (global positioning systems) for GIS (geographic information systems) mapping applications. Based on its fluvial and geomorphological trends, OBRI was dissected quantitatively and integrated into databases for species-specific GIS habitat queries. Substrate type, depth, above water river characteristics (pool/riffle/run), and substrate embeddedness were extracted to access specific habitats. To better pinpoint optimal microhabitat locations, a physical habitat suitability model was developed to rank preferred habitat locales. Rankings were sequentially broken into five categories: optimal, sub-optimal, marginal, sub-marginal, and poor habitat criteria. Habitat suitability findings for the interested species habitats varied tremendously, favoring fish species. Spotfin chub, Erimonax monacha, optimal habitat was found to cover 22.14 km of river length within OBRI (30 % of OBRI’s spatial extent). The blackside dace, Phoxinus cumberlandensis, (38.9 km) and the duskytail darter, Etheostoma percnurum, (50.9 km) met optimal habitat conditions that yielded 51% and 69% of OBRI’s spatial extent, respectively. In general, optimal habitats for the six mussels were sporadically distributed and had low occurrences. Primarily, these mussel species prefer highly embedded areas with very specific depths and pool/riffle/run conditions. Cumberland elktoe, Alasmidonta atropurea, optimal habitat ranges spanned across 4.32 km (6% of OBRI’s spatial extent) with most of the habitat characteristics in OBRI being marginal. The purple bean, Villosa perpurpurea, optimal habitat was identified within 2.61 km of OBRI (3.5% of OBRI’s spatial extent). Most of the physical conditions of OBRI supplied poor to sub-marginal habitat for the purple bean, at least from a thalweg perspective. Only 385 m coincided with optimal habitat for the cumberland bean, Villosa trabalis, (0.5% of OBRI’s spatial extent) with most habitats in long sub-marginal reaches. Optimal habitats for the cumberlandian combshell, Epioblasma brevidens, the tan riffleshell, Epioblasma florentina walkeri, and the littlewing pearlymussel, Pegias fibula, were deficient, only occurring in 484 m, 276 m, and 252 m of OBRI, respectively (0.7%, 0.4%, and 0.3% of OBRI’s spatial extent). Marginal to sub-marginal habitats dominated the park for these three mussel species.
187

Foraminiferal Assemblages on Sediment and Reef Rubble at Conch Reef, Florida USA

Stephenson, Christy Michelle 01 January 2011 (has links)
ABSTRACT Foraminiferal Assemblages on Sediments and Reef Rubble at Conch Reef, Florida USA Christy Stephenson Benthic foraminiferal assemblages are widely used to interpret responses of the benthic communities to environmental stresses. This study compares epibiotic foraminiferal assemblages, collected from reef rubble, with those from reef sediments. The study site, Conch Reef, is the site of the Aquarius Underwater Habitat research facility and includes protected areas used only for scientific studies. Although a number of studies have enumerated foraminiferal taxa from the Florida reef tract, no projects have focused on the assemblages that occur at Conch Reef. Sediment and reef rubbles samples were collected via SCUBA from a depth range of 13 to 26 m during October 2008. Foraminiferal assemblages were assessed and compared between the two sample types. A total of 117 foraminiferal species, representing 72 genera, 37 families, and 8 orders were identified in 13 sediment samples and 21 rubble samples. In the rubble samples, 70 genera were identified, including 12 symbiont-bearing genera representing 20% of the total assemblage, 12 stress-tolerant genera representing 6%, planktic foraminifers representing 1%, and 46 other smaller foraminiferal genera representing 73% of the total foraminiferal assemblage. The rubble samples were quite homogenous. The mean (+SD) Fisher alpha α diversity of genera in these samples was 12.9 + 1.4. Sediment samples included 60 of the same genera. The 12 symbiont-bearing genera represented 41% of the total assemblage, 10 stress-tolerant genera represented 3%, planktic taxa represented 2%, and 40 other smaller foraminiferal genera represented 54% of the total assemblage. Overall, the taxonomic assemblages were very similar between the sample types, with sediment assemblages clearly representing the local and regional reef foraminiferal assemblage. The mean (+SD) Fisher alpha α for sediment samples was 11.4 + 2.3, which is not significantly different from that found for the rubble samples. A concentration ratio comparing relative abundances in sediment vs. rubble samples revealed that shells of larger, symbiont-bearing taxa were about 2.5-5.5 times more concentrated in the sediment, indicating winnowing of smaller taxa. Shells of Siphonatera, an agglutinated miliolid, and Textularia, an agglutinated textularid, were more abundant in sediments than in rubble, indicating high preservation potential. The concentration ratio provides a new taphonomic index that reflects the size and durability of foraminiferal taxa. The mean FORAM Index (FI) for the sediment samples (5.57 + 0.83) indicates that water quality at Conch Reef is suitable for calcifying symbioses. The most abundant symbiont-bearing genera were Amphistegina, Laevipeneroplis, Asterigerina, and Archaias.
188

Roles and functions of sustainability indicators in river revitalization : a case study of Yuen Long Town Nullah

Tse, Wing-wah, 謝穎華 January 2014 (has links)
Sustainable development has been an emerging trend in worldwide projects for securing the assets available to future generations, yet, there are often disputes over the sustainability of a project. Sustainability indicators are therefore suggested to serve as a quantitative tool to analyze the changes and measure progress of a sustainable development. By engaging the public for identification of such indicators, their opinions of a development can be documented and then conveyed to the decision makers at the planning stage. It is anticipated that the actual needs of the local communities can be reflected in and communicated by these sustainability indicators. In this Study, Yuen Long Town Nullah was picked to be a pilot study to demonstrate the role and function of sustainability indicators. It is a part of the oldest drainage systems in Hong Kong and was constructed in the early 1960’s to alleviate flooding. Like many other nullahs, it was originated from natural watercourses and has then been straightened and provided with concrete bed and walls. Over the years, it has been complained of eyesore problem, foul smell, and accumulation of refuse. In order to address these urban problems in parallel with the lack of open space, revitalization of the Nullah has been opted for re-establishing riverscapes and providing valuable recreational space by turning the Nullah into community assets. In total, 202 sets of questionnaires were collected for gathering the general perception and identification of local sustainability indicators of Yuen Long Town Nullah. 4 interviews with various stakeholders were also conducted for giving comments on sustainability indicators, government’s policy towards sustainable development, recommendations on monitoring the sustainability progress and the sustainability indicators for developing Yuen Long Town Nullah based on their experiences. In general, the local communities concerned the environmental aspect the most but economic aspect the least. A sustainability indicator framework was proposed at the last part of this Study to conclude the findings from the questionnaire survey and the interviews. / published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
189

Monitoring the Influence of Acid Deposition on Soil and Implications to Forest Health in the Daniel Boone National Forest

Sanderson, Tyler M 01 January 2014 (has links)
Combustion of fossil fuels has contributed to many environmental problems including acid deposition. The Clean Air Act (CAA) was created to reduce ecological problems by cutting emissions of sulfur and nitrogen. Reduced emissions and rainfall concentrations of acidic ions have been observed since the enactment of the CAA, but soils continue to receive some acid inputs. Soils sensitive to acid deposition have been found to have low pH, a loss of base cations and a shift in the mineral phase controlling the activity of Al3+ and/or SO42-. If inputs continue, soil may be depleted of base cations and saturated with Al and could cause low forest productivity. Soil solutions from lysimeters were taken in the Daniel Boone National Forest to evaluate potential impacts of acid deposition. In addition, tree-ring growth and chemical analysis created a timeline of forest health and ion accumulation. Physicochemical characteristics of the soils revealed that sites were very low in base saturation and pH and high in exchangeable acidity. Soil solution data indicated that sites periodically received high acid inputs leading to saturation of Al in soils and the formation of Al-hydroxy-sulfate minerals. Given these conditions, long-term changes in soil chemistry from acid deposition are acknowledged.
190

The Hydrology of the Carroll Cave-Toronto Springs System: Identifying and Examining Source Mixing through Dye Tracing, Geochemical Monitoring, Seepage Runs, and Statistical Methods

Miller, Benjamin Verlinden 01 December 2010 (has links)
In karst areas relationships between activities occurring on the surface and the overall health of the subsurface environment are often highly interconnected. However, the complex nature of karst flow systems can often make identification of these connections difficult. Carroll Cave, a large stream cave system located in the central Missouri Ozarks, is known for its biological and speleological significance. A dye tracing project to delineate a Carroll Cave recharge area through dye tracing has identified an area of 18.5 km2 which contributes water to the cave. The water from Thunder River within Carroll Cave was positively traced to eight springs of the thirteen springs at a distributary spring system known as Toronto Springs. Through examination of the geochemistry of the individual springs, differences in water chemistry between the various outlets has become evident. Additional work with YSI Sonde dataloggers and consideration of carbonate chemistry relationships has sought to further define the variations in hydrochemical behavior, thus aiding in the discrimination potential spring sources. Primary sources thought to contribute water to the spring system include Carroll Cave and Wet Glaize Creek, with some minor influence from other losing streams in the vicinity. Seepage runs along Wet Glaize Creek have also identified major losing reaches, in close proximity to structural features, which may contribute water to Toronto Springs. Examination of the measured parameters and derived have identified that Carroll Cave and Wet Glaize Creek are the primary end members for Ca2+, Mg2+, HCO3-, specific conductance, and temperature. Using these parameters a two end member mixing model has been developed which describes the mixing zone setting at Toronto Springs and calculates the average proportions of flow contributions by the end members. By using a multi-proxy approach of dye tracing, seepage runs, and geochemistry for the individual springs, the source waters and pathways for the springs at Toronto Springs have been identified.

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