UNT Theses and Dissertations - 155 Matching Results

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On-Road Remote Sensing of Motor Vehicle Emissions: Associations between Exhaust Pollutant Levels and Vehicle Parameters for Arizona, California, Colorado, Illinois, Texas, and Utah

Description: On-road remote sensing has the ability to operate in real-time, and under real world conditions, making it an ideal candidate for detecting gross polluters on major freeways and thoroughfares. In this study, remote sensing was employed to detect carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxide (NO). On-road remote sensing data taken from measurements performed in six states, (Arizona, California, Colorado, Illinois, Texas, and Utah) were cleaned and analyzed. Data mining and explorat… more
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Date: May 2003
Creator: Dohanich, Francis Albert
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Organic carbon dynamics of the Neches River and its floodplain.

Description: A large river system typically derives the majority of its biomass from production within the floodplain. The Neches River in the Big Thicket National Preserve is a large blackwater river that has an extensive forested floodplain. Organic carbon was analyzed within the floodplain waters and the river (upstream and downstream of the floodplain) to determine the amount of organic carbon from the floodplain that is contributing to the nutrient dynamics in the river. Dissolved organic carbon was… more
Date: December 2007
Creator: Stamatis, Allison Davis
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Geology as a Georegional Influence on Quercus Fagaceae Distribution in Denton and Coke Counties of Central and North Central Texas and Choctaw County of Southeastern Oklahoma, Using GIS as an Analytical Tool.

Description: This study elucidates the underlying relationships for the distribution of oak landcover on bedrock and soil orders in two counties in Texas and one in Oklahoma. ESRI's ArcGis and ArcMap was used to create surface maps for Denton and Coke Counties, Texas and Choctaw County, Oklahoma. Attribute tables generated in GIS were exported into a spreadsheet software program and frequency tables were created for every formation and soil order in the tri-county research area. The results were both a vis… more
Date: December 2007
Creator: Maxey, George F.
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Analysis of the One-Horned Rhinoceros (Rhinoceros Unicornis) Habitat in the Royal Chitwan National Park, Nepal.

Description: This study analyzes the remaining suitable habitat of the one-horned rhinoceros, Rhinoceros unicornis, in Royal Chitwan National Park of Nepal. An April 2003 Landsat image was classified into eight land cover types: wetland, sand, water, mixed forest, sal forest, agriculture, settlement, and grassland. This image was converted into habitat suitability maps using cover, food, and water. The rhinoceros prefers grassland habitat with oxbow lakes and closed canopy during the monsoon season. Nomina… more
Date: December 2005
Creator: Thapa, Vivek
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Rainfall-runoff changes due to urbanization: a comparison of different spatial resolutions for lumped surface water hydrology models using HEC-HMS.

Description: Hydrologic models were used to examine the effects of land cover change on the flow regime of a watershed located in North-Central Texas. Additionally, the effect of spatial resolution was examined by conducting the simulations using sub-watersheds of different sizes to account for the watershed. Using the Army Corps of Engineers, Hydrologic Engineering Center Hydrologic Modeling System (HEC-HMS), two different modeling methods were evaluated at the different sub-watershed resolutions for four … more
Date: December 2005
Creator: Redfearn, Howard Daniel
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Simulation of physical and chemical processes in reservoirs: Two case studies.

Description: Managing water quality aspects requires the use of integrative tools that allow a holistic approach to this problem. Water quality models coupled to hydrodynamic models are these tools. This study presents the application of the water quality model WASP coupled to the hydrodynamic model DYNHYD for two distinct reservoirs: Lake Texoma and Tocoma Reservoir. Modeling the former included simulations of water velocities, water level, and four chemical and physical compounds: chlorides, dissolved oxy… more
Date: December 2005
Creator: García Iturbe, Selma L.
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Effects on Survival, Reproduction and Growth of Ceriodaphnia dubia following Single Episodic Exposure to Copper or Cadmium

Description: Effects of episodic exposures have gained attention as the regulatory focus of the Clean Water Act has shifted away from continuous-flow effluents. Standardized laboratory toxicity tests require that exposure be held constant. However, this approach may not accurately predict organism responses in the field following episodic exposures such as those associated with rain-driven runoff events or accidental pollutant discharge. Using a modified version of the 7-day short-term chronic test recomme… more
Date: August 2005
Creator: Turner, Philip K.
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A geospatial tool for assessing potential wildland fire risk in central Texas.

Description: Wildland fires in the United States are not always confined to wilderness areas. The growth of population centers and housing developments in wilderness areas has blurred the boundaries between rural and urban. This merger of human development and natural landscape is known in the wildland fire community as the wildland urban interface or WUI, and it is within this interface that many wildland fires increasingly occur. As wildland fire intrusions in the WUI increase so too does the need for too… more
Date: August 2005
Creator: Hunter, Bruce Allan
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Assessing Outcomes of a Recycling Education and Service Program within an Elementary School

Description: During the spring 2004 a pilot school recycling program was implemented within Robert E. Lee Elementary. The primary goal of the program was to determine how recycling education in the school would affect curbside recycling rates within the surrounding community. The program was a cooperative effort between the University of North Texas, City of Denton Solid Waste Department and Keep Denton Beautiful. Throughout the first months of the study during the spring 2004, an increase in curbside rec… more
Date: August 2005
Creator: Cunningham-Scott, Carey Beth
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Determination of Habitat Preferences of Pronghorn (Antilocapra americana) on the Rolling Plains of Texas Using GIS and Remote Sensing

Description: The Rocker b Ranch on the southern Rolling Plains has one of the last sizeable populations of pronghorn (Antilocapra americana) in Texas. To investigate habitat utilization on the ranch, pronghorn were fitted with GPS/VHF collars and were released into pastures surrounded by a variety of fences to determine how fence types affected habitat selection. Habitat parameters chosen for analysis were vegetation, elevation, slope, aspect, and distances to water, roads, and oil wells. Results showed … more
Date: May 2005
Creator: Aiken, Robin A.
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Solid phase microextraction of amino-dinitrotoluenes in tissue.

Description: TNT (2,4,6-trinitrotoluene) readily and predominantly transforms to 2ADNT (2-amino-4,6-dinitrotoluene) and 4ADNT (4-amino-2,6-dinitrotoluene) in environmental matrixes and tissues. Solid phase microextraction (SPME) was used to extract ADNTs (amino-dinitrotoluenes) from tissue as a potential method to investigate the recalcitrance of metabolically-generated ADNTs versus absorbed ADNTs. Tubifex tubifex was allowed to metabolize TNT into ADNTs in 24-hr static non-renewal exposure test followed b… more
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Date: December 2004
Creator: Tsui-Bowen, Alethea
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Revisiting Aldo Leopold's "Perfect" Land Health: Conservation and Development in Mexico's Rio Gavilan

Description: The Rio Gavilan watershed, located in Mexico 's northern Sierra Madre Occidental , has significance in conservation history. Upon visiting the remote, largely un­developed watershed during two hunting trips in the 1930s, renowned conservationist Aldo Leopold thought it was the best picture of land health he had seen. His main indicators of healthy land were slow water runoff rates regulating erosion and historical predator-prey relationships. The visits confirmed Leopold's concept of land h… more
Date: December 2004
Creator: Forbes, William
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Concentrations of Triclosan in the City of Denton Wastewater Treatment Plant, Pecan Creek, and the Influent and Effluent of an Experimental Constructed Wetland

Description: The Pecan Creek Waste Reclamation Plant in Denton, Texas, an activated sludge WWTP, was sampled monthly for ten months to determine seasonal and site variation in concentrations of triclosan (5-chloro-2-(2,4-dichlorophenoxy)phenol), an antibacterial additive. SNK separation after the highly significant ANOVA on ranked data were: summer = fall > winter = spring and influent > downstream = effluent = wetland inflow > wetland outflow (a=0.05). After the plant converted to ultraviolet disinfection… more
Date: August 2004
Creator: Waltman, Elise Lyn
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Green Improvements: A Consumer's Guide to Environmentally and Economically Responsible Home Repairs and Improvements for the North Central Texas Region

Description: The Consumer's Guide is designed to help consumers by providing guidelines for the purchase of specific energy-efficient household appliances- water heaters, air conditioning and heating systems, windows, dishwashers, refrigerators, clothes washers, and dryers. This serves two major purposes: to decrease the environmental impact of those products and to save consumers money over the lifetime of the products. The seven major appliances covered in this work are things that consumers tend to purch… more
Date: August 2004
Creator: Dickason, Deborah
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Surface Water and Groundwater Hydrology of Borrow-Pit Wetlands and Surrounding Areas of the Lewisville Lake Environmental Learning Area, Lewisville, Texas

Description: The focus of this study was to characterize the surface water and groundwater hydrology of borrow-pit wetlands located within the borders of the Lewisville Lake Environmental Learning Area (LLELA), east of the Elm Fork of the Trinity River. The wetlands were excavated into alluvial deposits downstream of the Lewisville Lake Dam. Both surface water and groundwater contribute to the hydro-period of the borrow-pit wetlands. Nearby marshes exhibit characteristics of groundwater discharge. Salinity … more
Date: August 2004
Creator: Dodd-Williams, Lynde L.
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Evaluation of the Economic, Social, and Biological Feasibility of Bioconverting Food Wastes with the Black Soldier Fly (Hermetia illucens)

Description: Food waste in the waste stream is becoming an important aspect of integrated waste management systems. Current efforts are composting and animal feeding. However, these food waste disposal practices rely on slow thermodynamic processes of composting or finding farmers with domestic animals capable of consuming the food wastes. Bioconversion, a potential alternative, is a waste management practice that converts food waste to insect larval biomass and organic residue. This project uses a native a… more
Date: August 2004
Creator: Barry, Tami
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Culturing Vallisneria americana for Restoration Efforts

Description: Robust Vallisneria americana was cultured for restoration purposes. Preliminary studies, with various iron treatments, were conducted to ascertain the amount of phosphorous release into the water column from sediments. There was a significant difference in the amount of phosphorous released if commercial sediment was used with a low iron amendment or without an iron amendment. The second study consisted of planting V. americana on two different sediment types while supplying half of the pla… more
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Date: May 2004
Creator: Tanski, Erin M.
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City of Denton Municipal Solid Waste Characterization and Management Strategies

Description: Due to concern about diminishing landfill space, the City of Denton contracted a municipal solid waste characterization study in 1999 that would identify materials for diversion. This paper describes the results of 5 1-week waste sorting events, a scale-house analysis, a recycling participation study, a recycler profile and a similar city study. The results of the characterization studies suggest that at least 50% of each waste stream is recyclable or divertible though paper products accounted … more
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Date: May 2004
Creator: Brady, Patricia D.
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Simulation of local watershed nutrient and sediment delivery to Lake Texoma.

Description: A hydrologic model and watershed export model was used to estimate the loading of nutrients and total suspended solids from un-gaged local watersheds associated with Lake Texoma. Discharge to the reservoir from local watersheds was predicted using a modification of the curve number method in HEC Hydrologic Modeling System (HEC-HMS). Event mean concentrations were applied to land use to estimate loadings of nutrients and TSS. Total discharge from the local watersheds was estimated to be 3.02 x 1… more
Date: May 2004
Creator: Upton, Alexandra C.
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Comparative Bioavailability of Dietary and Dissolved Cadmium to Freshwater Aquatic Snails

Description: Heavy metal bioaccumulation in aquatic organisms may occur through direct or indirect uptake routes. Research indicates that the significance of uptake route varies with contaminant and organism exposed. The relative importance of different metal sources in aquatic systems was investigated by exposing freshwater snails to dietary or dissolved sources of cadmium. Snails were exposed to control, contaminated food only, contaminated water only, and contaminated food and water treatments. During… more
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Date: December 2003
Creator: White, Jessica C.
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Modeling of Land Use Change Effects on Storm Water Quantity and Quality in the City of Carrollton and the North Texas Area

Description: Development and population are rapidly increasing in urbanizing areas of North Texas and so is the need to understand changes in storm water runoff flow and its contamination by nutrients, sediment, pesticides and other toxicants. This study contributes to this understanding and has two primary components: first, development of a graphical user interface for a geographic information system and storm water management database, and second, performing a two-scale hydrological modeling approach (th… more
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Date: December 2003
Creator: Duncan, Phillip Brent
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Management Tools for Prescribed Burning for Tallgrass Prairie Restoration at the Lewisville Lake Environmental Learning Area

Description: The Lewisville Lake Environmental Learning Area (LLELA) is a wildlife management area with tallgrass prairie, an endangered ecosystem. Essential ecosystem processes, especially fire, are part of restoration. To support fire management efforts at LLELA and surrounding areas, this project evaluated and developed tools for fire restoration. The four primary prairie grasses respond favorably to burning. Fuel loads and fuel models vary by scale and survey method. One- and 10-hour fuel moisture can b… more
Date: December 2003
Creator: Moreno, Maria C.
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Laboratory and field studies of cadmium effects on Hyalella azteca in effluent dominated systems.

Description: Laboratory single-species toxicity tests are used to assess the effects of contaminants on aquatic biota. Questions remain as to how accurately these controlled toxicity tests predict sitespecific bioavailability and effects of metals. Concurrent 42-day Hyalella azteca exposures were performed with cadmium and final treated municipal effluent in the laboratory and at the University of North Texas Stream Research Facility. Further laboratory testing in reconstituted hard water was also conduct… more
Date: August 2003
Creator: Stanley, Jacob K.
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Storm Water System Monitoring for the Small Municipality Under Phase II of the National Pollutant Discharge Elimination System

Description: Storm water quality can have a significant impact on receiving water bodies. The chief recipients of these impacts are aquatic life in the receiving water body and downstream water users. Over the last few decades, legislation, regulations, institutions and facilities have evolved to recognize the impact of urban storm water on receiving streams. This increased emphasis has caused contaminants in storm water to be identified as a major concern. This developing concern has generated an increased… more
Date: August 2003
Creator: Peacock, Steven
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