Open Access. Powered by Scholars. Published by Universities.®
- Institution
Articles 1 - 7 of 7
Full-Text Articles in Engineering
Bedload Transport Sampling, Characterization And Modeling On A Southern Appalachian Ridge And Valley Stream, Patrick Lasater Mcmahon
Bedload Transport Sampling, Characterization And Modeling On A Southern Appalachian Ridge And Valley Stream, Patrick Lasater Mcmahon
Doctoral Dissertations
Estimates of bedload transport rates developed from existing transport models are notoriously inaccurate(Wilcock 2001). The gravel bed models addressed in this study include the Meyer-Peter and Muller; Parker, Klingeman, and McLean; and Wilcock two-fraction models. The question of whether or not these models predict bedload transport rates in a Southern Appalachian Ridge and Valley stream is complicated by the fact that these models have only been previously assessed in terms of their agreement with bedload transport rates measured in the Western regions of the U.S. Further, due to the strongly non-linear form of bedload transport models discrete errors and cumulative …
Renovation Of Ammonia Contaminated Produced Water Using Constructed Wetlands, Donald Beebe
Renovation Of Ammonia Contaminated Produced Water Using Constructed Wetlands, Donald Beebe
All Dissertations
Pilot-scale wetland treatment systems were designed and constructed to evaluate renovation of simulated oilfield produced water contaminated with ammonia (20 mg/L ammonia-N). A process-based pilot-scale constructed wetland was designed to meet specific biogeochemical conditions for conversion of ammonia to nitrogen gas through microbial nitrification and denitrification. The process-based constructed wetland treated the simulated produced water to meet stringent discharge requirements (less than 1.2 mg/L ammonia-N). Clinoptilolite, a zeolite mineral, was evaluated for use in constructed wetlands to increase ammonia sorption and nitrification activity. Clinoptilolite increased wetland ammonia sorption capacity and served as a microbial carrier for nitrifying bacteria when ranges …
Using Qual2kw As A Decision Support Tool: Considerations For Data Collection, Calibration, And Numeric Nutrient Criteria, Andrew J. Hobson
Using Qual2kw As A Decision Support Tool: Considerations For Data Collection, Calibration, And Numeric Nutrient Criteria, Andrew J. Hobson
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Surface water quality in the United States is managed by the U.S. Environmental Protection Agency (EPA) under direction of the Clean Water Act. Designated uses are required for all state waters. Numeric or narrative water quality standards provide measures to determine if each waterbody meets the intended use. Narrative standards typically include vague terminology that is difficult to interpret and this has led EPA to encourage states to develop numeric criteria for nutrients in all its streams, rivers, and lakes. These numeric nutrient criteria are intended to stave off the harmful effects of over-growth of aquatic plants which can result …
Effect Of Cement Chemistry And Properties On Activation Energy, Andre J. Bien-Aime
Effect Of Cement Chemistry And Properties On Activation Energy, Andre J. Bien-Aime
USF Tampa Graduate Theses and Dissertations
The objective of this work is to examine the effect of cement chemistry and physical properties on activation energy. Research efforts indicated that time dependent concrete properties such as strength, heat evolution, and thermal cracking are predictable through the concept of activation energy. Equivalent age concept, which uses the activation energy is key to such predictions. Furthermore, research has shown that Portland cement concrete properties are affected by particles size distribution, Blaine fineness, mineralogy and chemical composition. In this study, four Portland cements were used to evaluate different methods of activation energy determination based on strength and heat of hydration …
Investigation Of Mercury Use, Release, Deposition, And Exposures In The Tampa Bay Area, Ryan Algernon Michael
Investigation Of Mercury Use, Release, Deposition, And Exposures In The Tampa Bay Area, Ryan Algernon Michael
USF Tampa Graduate Theses and Dissertations
I investigate the links between mercury use, release, deposition, and population exposure in Tampa Bay, with the focus of identifying levers for reducing population mercury exposures. To achieve this, I investigated the trends in mercury use and release by products and processes in the Tampa Bay area using a Material Flow Analysis. Analysis of USEPA National Emissions Inventory data over time (1999 - 2008) identified relevant air source emission categories, and explored and compared state and regional trends in mercury emissions. To understand source contributions to wet deposited mercury in the Tampa Bay area, I analyzed trends in mercury deposition …
Distribution And Occurrence Of Escherichia Coli In Water And Sediments At Grand Glaize Beach In Lake Of The Ozarks State Park, Jordan Lee Wilson
Distribution And Occurrence Of Escherichia Coli In Water And Sediments At Grand Glaize Beach In Lake Of The Ozarks State Park, Jordan Lee Wilson
Masters Theses
"Public swimming beaches at the Lake of the Ozarks State Park (LOSP) are popular vacationing spots for many Missourians; however, on several occasions Escherichia coli (E. coli) concentrations have exceeded standards set by the Missouri Department of Natural Resources (MDNR). Exceedances lead to beach closures which not only represent a potential public health threat but are also detrimental to the local economy and the public's perception of the lake's general water quality. In a collaborative effort between Missouri S&T, the United States Geological Survey (USGS) and the MDNR, an in-depth, two-summer study was conducted which included collection of …
Effect Of Localized Corrosion Of Steel On Chloride-Induced Concrete Cover Cracking In Reinforced Concrete Structures, Ezeddin Rafaa Busba
Effect Of Localized Corrosion Of Steel On Chloride-Induced Concrete Cover Cracking In Reinforced Concrete Structures, Ezeddin Rafaa Busba
USF Tampa Graduate Theses and Dissertations
Abstract: Concrete cover cracking due to reinforcement corrosion is widely accepted as a limit-state indicator in defining the end of functional service life for existing reinforced concrete (RC) structures undergoing corrosion. Many of the currently available durability prediction models are incapable of providing realistic estimates of remaining service lives of RC structures beyond the corrosion initiation point. Therefore, the need to incorporate the length of the corrosion propagation stage in a comprehensive durability prediction approach has recently received much research attention. Previous research focus however was mostly limited to the case of uniformly corroding reinforcement with only few studies addressing …