Digital Commons Network^™

Constrained Multi-Group Project Allocation Using Mahalanobis Distance, Abdulaziz Saud Alkabaa

Doctoral Dissertations

Optimal allocation is one of the most active research areas in operation research using binary integer variables. The allocation of multi constrained projects among several options available along a given planning horizon is an especially significant problem in the general area of item classification. The main goal of this dissertation is to develop an analytical approach for selecting projects that would be most attractive from an economic point of view to be developed or allocated among several options, such as in-house engineers and private contractors (in transportation projects). A relevant limiting resource in addition to the availability of funds is …

Ecology Of Organohalide-Respiring Dehalococcoides Mccartyi: Corrinoid Cofactor-Related Community Interactions And Controls Over Strain Selection, Burcu Şimşir

Doctoral Dissertations

Organohalides such as tetrachloroethene (PCE) and trichloroethene (TCE) are among the most prevalent toxic groundwater contaminants. Remediation of organohalide-contaminated sites has high priority, and efficient and cost-effective remedies are needed to prevent environment and human exposure through contaminated water. Bacterial organohalide-respiration plays a major role in organohalide detoxification. Dehalococcoides mccartyi (Dhc) are key mediators in bioremediation, since only Dhc strains have been documented in complete detoxification of chlorinated ethenes to benign ethene. Dhc depends on other microorganisms in the environment for essential growth requirements (e.g., hydrogen and vitamins). For successful implementation of the reductive dechlorination to remediate contaminated …

Bioremediation Of Chlorinated Ethenes: Ph Effects, Novel Dechlorinators And Decision-Making Tools, Yi Yang

Doctoral Dissertations

Chlorinated solvents have been widely used in different areas of modern society. Usage of these chlorinated solvents was not necessarily accompanied with proper handling and disposal of these hazardous compounds, which caused a variety of environmental problems and continues to affect human health. Remediation of chlorinated ethenes contaminated sites has high priority for state regulators and site owners. Among the available treatment technologies, bioremediation shows great promise as a cost-effective corrective strategy for a variety of environmental pollutants. Prerequisites are that the microbiology involved in contaminant degradation and geochemical factors, such as pH, are understood, so that bioremediation technologies can …

Potential Emissions And Exposures Of Toxic Organics From Storage Tanks For Chemical Additions In Hydraulic Fracturing: A Modeling Approach, Huan Chen

Doctoral Dissertations

Hydraulic fracturing has promoted the exploitation of natural gas in the United States (U.S.). However, the storing and emptying of chemical additives in hydraulic fracturing wells may pose adverse effects through inhalation exposures. Based on the information about hydraulic fracturing fluids, this study investigated: 1) water volumes used to mix chemical additives for making up the hydraulic fracturing fluids; 2) chemical species, concentrations and their degradability in the hydraulic fracturing fluids; 3) emissions of organics from chemical storage tanks; and 4) the occupational inhalation exposures by toxic and organic vapors.

Results shows for 80,047 wells fractured between 2008 and 2014 …

Exploring The Influence Of Urban Watershed Characteristics And Antecedent Climate On In-Stream Pollutant Dynamics, Laurel Elizabeth Christian

Masters Theses

Understanding pollutant fate and transport in urban watersheds is a challenging endeavor, as heterogeneity of land use, precipitation patterns, and pollutant loadings add complexity to the system. As a result, many currently utilized water quality models exhibit poor performance. One main challenge in urban system modeling is the lack of quality data sets for model development, calibration, and testing, resulting in the need for high quality data collection. Although recent studies have begun to investigate pollutant transport in urban watersheds to aid these models, these studies have focused primarily on the end-of-pipe as the point of interest (i.e. prior to …

Lattice Boltzmann Methods For Wind Energy Analysis, Stephen Lloyd Wood

Doctoral Dissertations

An estimate of the United States wind potential conducted in 2011 found that the energy available at an altitude of 80 meters is approximately triple the wind energy available 50 meters above ground. In 2012, 43% of all new electricity generation installed in the U.S. (13.1 GW) came from wind power. The majority of this power, 79%, comes from large utility scale turbines that are being manufactured at unprecedented sizes. Existing wind plants operate with a capacity factor of only approximately 30%. Measurements have shown that the turbulent wake of a turbine persists for many rotor diameters, inducing increased vibration …

3d Multi-Scale Behavior Of Granular Materials Using Experimental And Numerical Techniques, Andrew Michael Druckrey

Doctoral Dissertations

Constitutive modeling of granular material behavior has generally been based on global response of laboratory-size specimens or larger models with little understanding of the fundamental mechanics that drive the global response. Many studies have acknowledged the importance of micro-scale and meso-scale mechanics on the constitutive behavior of granular materials. However, much knowledge is still missing to develop and improve robust micromechanical constitutive models. The research in this dissertation contributes to this knowledge gap for many potential applications using novel experimental techniques to investigate the three-dimensional (3D) behavior of granular materials. Critical micromechanics measurements at multiple scales are investigated by combining …

The Use Of Sodium Persulfate In Hydraulic Fracturing Fluids: A Degradation Study Based On Furfural, Katherine Elizabeth Manz

Masters Theses

Hydraulic fracturing has allowed natural gas to become a viable energy source via extraction of unconventional shale reserves, but this process requires an enormous amount of water. To ensure a productive fracture, a proprietary blend of chemical additives is added to the water. In this research, a hydraulic fracturing chemical additive – an enzyme breaking agent – is analyzed for organic components using gas chromatography mass spectrometry. The chemical changes that occur over the course of a fracture are also investigated using one model chemical found in the additive, furfural, in order to help assess the environmental risk that hydraulic …

Bridge Deck Research At The University Of Tennessee: A Summary Thesis, Lindsey Brooke Phelps

Masters Theses

Currently, there has been no compilation of all the research the University of Tennessee has completed on chloride ion penetration in concrete bridge decks. The following thesis is a brief summary of the work that has been completed under Dr. Edwin Burdette’s direction over the last six years along with some additional literature review. The testing consisted of Surface Resistivity and Rapid Chloride Ion Penetration testing. This testing showed that there is, in fact a correlation between the two test methods, though SR testing is much easier to conduct. Considerable testing was completed on bridge decks throughout the state of …

Long-Term Health Risk Of Climate Change Associated Surface Pm2.5 Concentration Variation: Multiple Accmip Model Data Under Different Emission Scenarios (Rcp26, 45, 60, 85) And Population Scenarios (Ssp1, Ssp2, Ssp3), Xiufen Zhu

Masters Theses

In this study, multiple models from Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) are utilized to derive the global burden of disease of chronic obstructive pulmonary disease (COPD), lung cancer (LNC), and lower respiratory infection (LRI) derived from surface PM_2.5 elevation. Various Representative Concentration Pathways and Shared Socio-economic Pathways scenarios are compared as well as various models to deduct the impact from various scenarios. The time series variation and seasonal variation are also illustrated in this study. Multi-model ensemble was conducted to reduce the deviation in model projection output.

Projection shows increase in the population normalized relative risk …

Extraction And Recovery Of 2-Butoxyethanol From Aqueous Phases Containing High Saline Concentration, Katherine E. Manz, Kimberly E. Carter

Faculty Publications and Other Works -- Civil & Environmental Engineering

Ethylene glycol monobutyl ether (EGBE), also known as 2-butoxyethanol (2-BE), has been identified as a contaminant in hydraulic fracturing fluids. In order to determine the presence of 2-BE in hydraulic fracturing chemical additives, a reliable method for recovering 2-BE from aqueous phases by liquid-liquid extraction combined with gas chromatography/mass spectrometry (GC/MS) was established. The liquid-liquid extraction method was applied to samples matrices containing various amounts of salt. Using methylene chloride for liquid-liquid extraction in a sample to solvent ratio of 1:3, ≥99% 2-BE recovery may be achieved with less than 5% standard error. The limit of detection was determined to …

Model Development Of Dust Emission And Heterogeneous Chemistry Within The Community Multiscale Air Quality Modeling System And Its Application Over East Asia, Xinyi Dong, Joshua S. Fu, Kan Huang, Daniel Tong, Guoshun Zhuang

Faculty Publications and Other Works -- Civil & Environmental Engineering

The Community Multiscale Air Quality (CMAQ) model has been further developed in terms of simulating natural wind-blown dust in this study, with a series of modifications aimed at improving the model's capability to predict the emission, transport, and chemical reactions of dust. The default parameterization of initial threshold friction velocity constants are revised to correct the double counting of the impact of soil moisture in CMAQ by the reanalysis of field experiment data; source-dependent speciation profiles for dust emission are derived based on local measurements for the Gobi and Taklamakan deserts in East Asia; and dust heterogeneous chemistry is also …

Colwellia Psychrerythraea Strains From Distant Deep Sea Basins Show Adaptation To Local Conditions, Stephen M. Techtmann, Kathleen S. Fitzgerald, Savannah C. Stelling, Dominique C. Joyner, Sagar M. Uttukar, Austin P. Harris, Noor K. Alshibli, Steven D. Brown, Terry C. Hazen

Faculty Publications and Other Works -- Civil & Environmental Engineering

Many studies have shown that microbes, which share nearly identical 16S rRNA genes, can have highly divergent genomes. Microbes from distinct parts of the ocean also exhibit biogeographic patterning. Here we seek to better understand how certain microbes from the same species have adapted for growth under local conditions. The phenotypic and genomic heterogeneity of three strains of Colwellia psychrerythraeawas investigated in order to understand adaptions to local environments. Colwellia are psychrophilic heterotrophic marine bacteria ubiquitous in cold marine ecosystems. We have recently isolated two Colwellia strains: ND2E from the Eastern Mediterranean and GAB14E from the Great Australian Bight. …

Response Of Microbial Community Structure To Clay Flocculation Of Harmful Algal Blooms, Chunyi Chen

Doctoral Dissertations

Harmful algal blooms are cosmopolitan and can produce extremely dangerous toxins that can sicken or kill people and animals, and create dead zones in the water. The U.S. economic loss caused by algal blooms is $82 million every year. Clay-based flocculation techniques have been developed to mitigate algal blooms; however, the potential impacts on the microbial community are poorly understood. This dissertation includes multi-scale experiments (Jar, field, microcosms) to study the response of microbial community structure and function to clay flocculation of algal blooms.

Jar tests of removal of Microcystis aeruginosa by chitosan and two types of commercially available clays …

Second Creek Monitoring, Haley Whitaker, Aaron Young, Ryan Wagner, Saajid Haque, Benjamin Parrott, Richard Fagan

Chancellor’s Honors Program Projects

No abstract provided.

Sidewalk Infrastructure Improvements Design For Calhoun, Tn, Bailee Young, Mark Nichols, Trenton Smith, Brian Walker, Liam Weaver, Marquise Webb

Chancellor’s Honors Program Projects

No abstract provided.

Sidewalk Infrastructure Improvements Design For Calhoun, Tn, Liam Marten Weaver, Bailee Young, Brian Walker, Mark Nichols, Marquise Webb, Trenton Smith

Chancellor’s Honors Program Projects

No abstract provided.

Nickajack Industrial Park Development Plan, Kristina N. King, Catherine Lowe, Seth E. Gilliland, Brooklynn Isom, Jaylyn Johnson, Andrew Fulkerson, Christopher Royer

Chancellor’s Honors Program Projects

No abstract provided.

Isolation And Characterization Of Microbial Communities From Hydraulic Fracturing Fluids, Sheridan S. Brewer 6284984

Chancellor’s Honors Program Projects

No abstract provided.

Denso Eco Park Infrastructure Beautification Project, Brandy N. Manka

Chancellor’s Honors Program Projects

No abstract provided.

Kinematic Behavior Of Sheared Sand With Emphasis On Particle To Particle Interaction Using Computed Tomography, Maha Fawaz Jarrar

Masters Theses

Granular materials are a three-phase mixture of solid, liquid, and gas that exhibit complex engineering properties. They have a heterogeneous composition in nature and consist of many discrete particles with complex interactions. Granular materials are commonly used in many civil engineering construction projects, therefore, a better understanding of behavior of granular materials may result in safe and economical design. This thesis is a compilation of two related topics. A 3D systematic experimental study that investigates the influence of particle morphology, confining pressure, and specimen density on the failure mode of sheared sand is presented. Three uniform sand specimens with different …

A Mobile Canoe-Mounted, Geo-Referenced, 3-D Water Quality Analyzer, Alex Shpik, Alysse Ness, Ryan Vernich

EURēCA: Exhibition of Undergraduate Research and Creative Achievement

Water quality analysis is vital to ensure the health of water sources, as well as identifying pollutants and modeling how they affect a river system. Current methods of collecting water samples consist of stationary samplers that measure changes in water quality at only one location over time. We have designed a mobile, canoe-mounted, water quality analyzing system that will enable researchers to efficiently collect a large number of water quality samples with an associated GPS location and depth for each data point. While the canoe travels in parallel swaths bank to bank, the unit will alternately collect samples from 3 …