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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.
1

Baseline survey and habitat analysis of aquatic salamanders in the Pigeon River, North Carolina

Maxwell, Nikki J 01 December 2009 (has links)
The Pigeon River was severely impacted beginning in the early 1900s by a paper mill located in Canton, North Carolina. The mill discharged chemical byproducts into the Pigeon River until 1992 when the paper mill modified their processes. As a result, water quality improved but the status of salamander species in the Pigeon River was unknown. Worldwide amphibian declines over the last 20 years have drawn attention to the need for more research and a better understanding of species-specific habitat relationships. There is concern about amphibian population declines because amphibians are critical to the balance of ecosystems and are considered exceptional indicators of environmental health. The objectives of this study were: 1) to conduct a baseline survey of salamander species composition in the Pigeon River watershed, 2) to determine if salamander populations differ above and below the Canton paper mill, and 3) to attempt to explain variance in salamander abundance, richness and diversity by comparing water quality and substrate characteristics among streams. Eight stations were examined on the Pigeon River, with four stations located above the paper mill and four stations below. We also chose three stations on each of four tributaries, Big Creek, Fines Creek, Jonathan Creek and Richland Creek. Snorkel surveys were completed in the summer of 2009. Five of eight species of stream salamanders were found that historically existed in Haywood County, NC: Eastern hellbender, Blue Ridge two-lined salamander, shovel-nosed salamander, black-bellied salamander and spring salamander. No salamanders were found in the main channel of the Pigeon River below the mill. Eastern hellbenders and Blue Ridge two-lined salamanders preferred substrates consisting of rubble and avoided bedrock. Percent rubble was the only variable retained in substrate models and was positively related to salamander abundance, richness and diversity. Conductivity, salinity, and water temperature were higher in the Pigeon River below the mill than at all other sites. Salamander abundance was explained by dissolved oxygen, pH, and stream width in water quality models. The results of this study suggest salamander abundance was negatively associated with the Pigeon River below the mill because of poor water quality and not habitat availability.
2

Baseline survey and habitat analysis of aquatic salamanders in the Pigeon River, North Carolina

Maxwell, Nikki J 01 December 2009 (has links)
The Pigeon River was severely impacted beginning in the early 1900s by a paper mill located in Canton, North Carolina. The mill discharged chemical byproducts into the Pigeon River until 1992 when the paper mill modified their processes. As a result, water quality improved but the status of salamander species in the Pigeon River was unknown. Worldwide amphibian declines over the last 20 years have drawn attention to the need for more research and a better understanding of species-specific habitat relationships. There is concern about amphibian population declines because amphibians are critical to the balance of ecosystems and are considered exceptional indicators of environmental health.The objectives of this study were: 1) to conduct a baseline survey of salamander species composition in the Pigeon River watershed, 2) to determine if salamander populations differ above and below the Canton paper mill, and 3) to attempt to explain variance in salamander abundance, richness and diversity by comparing water quality and substrate characteristics among streams. Eight stations were examined on the Pigeon River, with four stations located above the paper mill and four stations below. We also chose three stations on each of four tributaries, Big Creek, Fines Creek, Jonathan Creek and Richland Creek. Snorkel surveys were completed in the summer of 2009. Five of eight species of stream salamanders were found that historically existed in Haywood County, NC: Eastern hellbender, Blue Ridge two-lined salamander, shovel-nosed salamander, black-bellied salamander and spring salamander. No salamanders were found in the main channel of the Pigeon River below the mill. Eastern hellbenders and Blue Ridge two-lined salamanders preferred substrates consisting of rubble and avoided bedrock. Percent rubble was the only variable retained in substrate models and was positively related to salamander abundance, richness and diversity. Conductivity, salinity, and water temperature were higher in the Pigeon River below the mill than at all other sites. Salamander abundance was explained by dissolved oxygen, pH, and stream width in water quality models. The results of this study suggest salamander abundance was negatively associated with the Pigeon River below the mill because of poor water quality and not habitat availability.
3

Energy Management System in Naval Submarines

January 2020 (has links)
abstract: An optimal energy scheduling procedure is essential in an isolated environment such as naval submarines. Conventional naval submarines include diesel-electric propulsion systems, which utilize diesel generators along with batteries and fuel cells. Submarines can charge the batteries by running diesel-electric generators only at the surface or at snorkeling depth. This is the most dangerous time for submarines to be detectable by acoustic and non-acoustic sensors of enemy assets. Optimizing the energy resources while reducing the need for snorkeling is the main factor to enhance underwater endurance. This thesis introduces an energy management system (EMS) as a supervisory tool for the officers onboard to plan energy schedules in order to complete various missions. The EMS for a 4,000-ton class conventional submarine is developed to minimize snorkeling and satisfy various conditions of practically designed missions by optimizing the energy resources, such as Lithium-ion batteries, Proton-exchange membrane fuel cells, and diesel-electric generators. Eventually, the optimized energy schedules with the minimum snorkeling hours are produced for five mission scenarios. More importantly, this EMS performs deterministic and stochastic operational scheduling processes to provide secured optimal schedules which contains outages in the power generation and storage systems. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2020
4

Cyberbullying Detection Using Weakly Supervised and Fully Supervised Learning

Abhishek, Abhinav 22 September 2022 (has links)
No description available.

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