Engineering Commons^™

Characterization Of Radiotolerance In Potato And Development Of A Gamma Radiation Phytosensor., Robert Graham Sears

Doctoral Dissertations

As humans pursue space travel and nuclear energy, the risk of harm from ionizing radiation increases. On Earth or in space, plants are essential to our personal and environmental health. Plants serve as sentinels, bioremediators and food sources in areas of high ionizing radiation, therefore it is essential to understand how ionizing radiation affects plant biology. This work aimed to understand plant responses to ionizing radiation in the potato chassis and apply that knowledge to generate novel phenotypes for nuclear energy and space applications. The first gamma radiation phytosensor was developed for monitoring at standoff distances greater than three meters. …

Characterization Of Lignin Structural Variability And The Associated Application In Genome Wide Association Studies, Nathan D. Bryant

Doctoral Dissertations

Poplar (Populus sp.) is a promising biofuel feedstock due to advantageous features such as fast growth, the ability to grow on marginal land, and relatively low lignin content. However, there is tremendous variability associated with the composition of biomass. Understanding this variability, especially in lignin, is crucial to developing and implementing financially viable, integrated biorefineries. Although lignin is typically described as being comprised of three primary monolignols (syringyl, guaiacyl, p-hydroxyphenyl), it is a highly irregular biopolymer that can incorporate non-canonical monolignols. It is also connected by a variety of interunit linkages, adding to its complexity. Secondary cell wall …

Examining The Relationship Between Lignocellulosic Biomass Structural Constituents And Its Flow Behavior, Ekramul Haque Ehite

Doctoral Dissertations

Lignocellulosic biomass material sourced from plants and herbaceous sources is a promising substrate of inexpensive, abundant, and potentially carbon-neutral energy. One of the leading limitations of using lignocellulosic biomass as a feedstock for bioenergy products is the flow issues encountered during biomass conveyance in biorefineries. In the biorefining process, the biomass feedstock undergoes flow through a variety of conveyance systems. The inherent variability of the feedstock materials, as evidenced by their complex microstructural composition and non-uniform morphology, coupled with the varying flow conditions in the conveyance systems, gives rise to flow issues such as bridging, ratholing, and clogging. These issues …

Understanding Lignin’S Fast Pyrolysis Through Examination Of The Thermolysis Mechanisms Of Model Oligomers, Ross Wesley Houston

Doctoral Dissertations

The lignocellulosic biorefinery is a visionary concept that endeavors to provide an alternative to fossil-based refineries by producing biobased fungible fuels and specialty chemicals almost exclusively derived currently from petroleum refineries. This vision of the lignocellulosic biorefinery can only be realized if all fractions of lignocellulosic biomass are efficiently deconstructed and valorized to generate a diverse portfolio of products to sustain it against market vicissitudes. Of the three main structural constituents of lignocellulosic biomass (i.e., cellulose, hemicellulose, and lignin), lignin is underutilized despite being the most abundant renewable source of aromatic platform chemicals, representing a growing 250 billion dollar market. …

Tomato Flower Detection And Three-Dimensional Mapping For Precision Pollination, Kaitlyn Mckensie Nelms

Masters Theses

It is estimated that nearly 75% of major crops have some level of reliance on pollination. Humans are reliant on fruit and vegetable crops for many vital nutrients. With the intensification of agricultural production in response to human demand, native pollinator species are not able to provide sufficient pollination services, and managed bee colonies are in decline due to colony collapse disorder, among other issues. Previous work addresses a few of these issues by designing pollination systems for greenhouse operations or other controlled production systems but fails to address the larger need for development in other agricultural settings with less …

Analysis Of Physicochemical Properties And Terrestrial Dynamics Of Mechanically Formed Micro-Nano Scaled Particles From Agricultural Plastic Mulches, Anton Friedrich Astner

Doctoral Dissertations

Release of microplastics (MPs) and nanoplastics (NPs) into agricultural fields is of great concern due to their reported ecotoxicity to organisms that provide beneficial service to the soil such as earthworms, and the potential ability of MPs and NPs to enter the food chain. Most fundamental studies of the fate and transport of plastic particulates in terrestrial environments employ idealized MP materials as models, such as monodisperse polystyrene spheres. In contrast, plastics that reside in agricultural soils consist of polydisperse fragments resulting from degraded films employed in agriculture. There exists a need for more representative materials in fundamental studies of …

Biomass Conversion To Bio-Derived Materials And Their Applications, Luna Liang

Doctoral Dissertations

Nowadays, fossil fuels still serve as the primary global energy resource. Replacing fossil fuels with renewable sources of energy and developing efficient energy storage technology is an urgent problem to solve. Lignocellulosic biomass has been investigated as a promising alternative for the production of biofuels, chemicals, and materials. In this dissertation, we studied the thermochemical biomass conversion strategies via different pretreatments strategies (e.g. dilute acid, ethanol, tetrahydrofuran, gamma-valerolactone) and genetic modification to overcome the biomass recalcitrance and achieve efficient conversion process. The biomass component structure of lignin and cellulose after thermal treatments were characterized and analyzed.

To further explore the …

Co2 Adsorption Using Mg-Mof-74/Activated Biochar Composites Produced From The Pyrolysis Of Lignocellulosic Biomass, Conner Brosdan Pope

Masters Theses

Adsorption is a promising carbon capture and storage (CCS) technology with porous solids like activated biochar (AB), graphene oxides (GO), and metal-organic frameworks (MOF) exhibiting different advantages related to separating carbon dioxide (CO₂) from gas mixtures. Accordingly, the synthesis of MOF/GO composites demonstrates synergism between CO₂ adsorption-driving physicochemical characteristics of MOFs and GOs. However, the synthesis of MOF/AB composites has not been explored in the literature to date even though AB shares many physical and chemical similarities with GO. This research project aimed to synthesize MOF/AB composites with appropriate physicochemical characteristics and CO₂ adsorption capacities for …

Approaches To Studying Bacterial Biofilms In The Bioeconomy With Nanofabrication Techniques And Engineered Platforms., Michelle Caroline Halsted

Doctoral Dissertations

Studies that estimate more than 90% of bacteria subsist in a biofilm state to survive environmental stressors. These biofilms persist on man-made and natural surfaces, and examples of the rich biofilm diversity extends from the roots of bioenergy crops to electroactive biofilms in bioelectrochemical reactors. Efforts to optimize microbial systems in the bioeconomy will benefit from an improved fundamental understanding of bacterial biofilms. An understanding of these microbial systems shows promise to increase crop yields with precision agriculture (e.g. biosynthetic fertilizer, microbial pesticides, and soil remediation) and increase commodity production yields in bioreactors. Yet conventional laboratory methods investigate these micron-scale …

Phylogenetics And Association Analyses Illustrate Substantial Cryptic Diversity Of A Newly Isolated Collection Of Cenococcum Geophilum, Jessica Velez

Doctoral Dissertations

The ectomycorrhizal fungus Cenococcum geophilum is distributed worldwide across multiple climates and soil types and is known to positively associate with a multitude of plant genera, possibly contributing to plant ability to tolerate inorganic contaminants in a soil environment. New C. geophilum isolates are easily cultured from soils in a laboratory setting, making this an ideal candidate for a model species with which to study multiple plant-fungal effects across a collection of novel isolates. However, C. geophilum is also genetically complex and, at 178Mbp, features one of the largest fungal genomes, necessitating the use of the novel restriction-associated DNA sequencing …

An Investigation Of Surface Water Sediment Source Tracking Using Bacterial Metagenomics And Elemental Fingerprinting, Yanchong Huangfu

Doctoral Dissertations

Excess suspended sediment in river systems commonly degrades surface water quality. A sediment source tracking approach is necessary to target management practices that will reduce significant sources of sediment in rainfall runoff and restore water quality. Sediment source tracking utilizes the biogeochemical characteristics of sediment, often paired with a mathematical model, to link eroding source materials and in-stream suspended sediment. However, there are still many questions left unanswered in using this approach, including simultaneously identifying fecal contamination sources, quantifying the reliability of sediment tracers, and methods to assess the accuracy of sediment source identification. The research herein utilized the microbial …

Natural Ventilation Models And Production Management In An Experimental High Tunnel, Muzi Zheng

Doctoral Dissertations

High tunnels (HTs) help producers to be more profitable through crop protection and extension of growing season. Proper ventilation and heat managements inside HTs are crucial for adjusting inner microclimates and future obtaining marketable crop production. This study first analyzed daytime ventilation rates that responds to the changes of external weather conditions in a Gothic-type HT located in eastern Tennessee. A mathematical energy balance model and instrumental measurement serve as validation data were developed with a good agreement for ventilation rates (R²>0.70). The coupling of energy balance model and air-flux calculation based on external weather parameters can be …

Phototherapy Mounting System For Inpatient Rehabilitation, Kelsey Henderson, Elizabeth Fortunato, Jacob Dixon

Chancellor’s Honors Program Projects

No abstract provided.

Rural School Wastewater Treatment System, Parker J. Dulin, Payton M. Smith, James W. Swart

Chancellor’s Honors Program Projects

No abstract provided.

Yield Measurement System For Seed Corn: Improving Dynamic Weight Accuracy And Harvest Area Determination, Fatima Ellyn Murillo

Masters Theses

A prototype weight-based yield mapping system for seed corn production was developed at the University of Tennessee (UTK) and field tested in Iowa. The first chapter of the following study focuses on assessing the accuracy of this yield mapping system which employs a novel yield prediction and analysis software called Yield Analyzer. Yield Analyzer was designed using a rule-based system for producing yield maps with minimal user input by automatically determining acceptable ranges for known dependent variables that contribute to dynamic weight measurement errors.

The second chapter of this thesis covers the development of a non-intrusive, machine vision technique to …

An Economic Evaluation Of A Biofuel Supply Chain Utilizing Multiple Feedstocks, Huaqi Zhang

Masters Theses

Biomass is considered as one potential feedstock for biofuel production. However, the high cost of biomass-to-biofuel supply chain, attributed to biomass’s low bulk density and resulting harvest, storage, and transportation challenges, has been a major hindrance to the success of biomass-based biofuel industry. In addition, the issue of dry matter losses during storage for a feedstock has affected biomass quantity and quality if the feedstock is stored for several months after a single harvest in a year. One potential way to improve the economics of biomass supply chain is to reduce storage need and enhance the utilization of harvest equipment …

The Impacts Of Biopolymer-Ionic Liquid Interactions On The Utilization Of Lignocellulosic Biomass, Jing Wang

Doctoral Dissertations

In the bioenergy field, the recalcitrance of lignocellulosic biomass has been mainly attributed to lignin. Many ionic liquid (IL) pretreatments were performed to maximize the removal of lignin. However, those methods seriously degraded lignin and hemicellulose, and could generate lignin or hemicellulose for developing an integrated biorefinery that utilizes efficiently the whole biomass. To fulfill the requirements of the integrated biorefineries, this dissertation explored the interactions between biopolymers and IL for a better utilization of lignocellulosic biomass as feedstock. By removing a large portion of hemicellulose, through an autohydrolysis, this physical and chemical barrier for IL diffusion was dismantled and …

Influence Of Application Technology On Foliar Fungicide Efficacy On Cercospora Sojina Infected Soybean, Shawn Alan Butler

Masters Theses

Due to the constant concern with off-target contamination and application technology requirements associated with future herbicide-tolerant crops, the use of drift-reduction nozzle technology (DRT) may increase. The primary objective of this research was to evaluate the effects of coarse droplets generated by drift-reduction nozzles on foliar fungicide efficacy and residual in soybean infected by frogeye leaf spot caused by Cercospora sojina. No differences in disease control, soybean yield, spray retention, and residual when applying Quadris Top SB, a premix of azoxystrobin and difenoconazole, using nozzles that produce either a medium or ultra coarse droplet spectrum were determined.

Due to …

Removal Of Trace Organic Compounds In Domestic Wastewater Using Recirculating Packed-Bed Media Filters, Brittani Nikole Perez

Masters Theses

Pharmaceuticals and personal care products (PPCPs) are commonly detected in the environment resulting from their survival from conventional wastewater treatment systems. More information is needed about the fate and transfer of these trace organic compounds in domestic wastewater and their associated risks so that efficient strategies for their removal can be developed for both large/small scale treatment systems. This study aimed to determine whether onsite wastewater treatment systems were capable of providing PPCP removal, in addition to quantifying different forms of removal (biodegradation/sorption). A column study was constructed to determine the removal efficiencies of 3 target PPCPs, endocrine disrupting compound …

Modeling Water Quality For Switchgrass Crop Production: Implications For Bioenergy Sustainability In East Tennessee, Zachariah Tzvi Seiden

Masters Theses

With passing of the US Energy Independence and Security Act (EISA) of 2007, there has been considerable research conducted on the sustainability of bioenergy crop production in the United States; switchgrass has shown particular potential for bioenergy production in East Tennessee. Many studies evaluating the environmental impact switchgrass has on runoff and water quality use the Soil and Water Assessment Tool (SWAT) for watershed modeling. Because SWAT is a lumped watershed model, it evaluates the result of hydrological processes for each hydrologic response unit (HRU), without accounting for the physical interactions between these HRUs. The Water Erosion Prediction Project (WEPP) …

Evaluation Of Multiple Disinfection Methods To Mitigate Contaminated Irrigation Water, Tianju Chang

Masters Theses

Outbreak of foodborne pathogens associated with fresh produce is a concern to produce growers. Irrigation water is one of the pathways of produce contamination. The U.S. Food and Drug Administration (FDA) proposed a set of guidelines for irrigation water that includes a maximum generic E.coli count lower than 126MPN/100mL. Irrigation is typically a continuous-flow process: water is withdrawn from a source and applied to a crop. In order to disinfect irrigation water, a process must be developed to provide treatment while the water is in the hydraulic network. However, studies related to the continuous flow irrigation water disinfection (CFIWD) system …

Estimating Streambank Erosion Using Gps-Based Watershed-Scale Video Mapping And Usepa Bancs For The Development Of Sediment Tmdls, Kelsey Jo Hensley

Masters Theses

According to the United States Environmental Protection Agency (USEPA), sediment is one of the most common water pollutants in the nation’s rivers. Consequently, the identification of streambank locations with high erosion potential is important in reducing sediment input via management and monitoring practices. Furthermore, the estimation of erosion rates and sediment loads can assist in the development of Total Maximum Daily Loads (TMDLs). The objective of this study was to integrate two USEPA-recommended approaches with the Streambank Video Mapping System (SVMS) in order to predict site-specific Total Daily Sediment Loads (TDSLs) and calculate sediment TMDLs for streambank erosion over several …

Biodegradation And Photodegradation Of Polylactic Acid And Polylactic Acid/ Polyhydroxyalkanoate Blends Nonwoven Agricultural Mulches In Ambient Soil Conditions, Sathiskumar Dharmalingam

Doctoral Dissertations

Agricultural mulch films, typically made of petroleum-based polyethylene, improve crop productivity by controlling weeds and providing microclimate. Extreme fragmentation of films imposes labor and disposal costs, not to mention environmental problems during and after service life. Although mulches made of biodegradable polymers such as cellulose, (nonbiobased) poly (butylene adipate-co-terephthalate) and polybutylene succinate are employed in the field, the fate of biodegradation of additives in mulches is still questionable in addition to service life until the harvesting. Nonwovens, made of biobased polymers such as poly (lactic acid) (PLA) and PLA-polyhydroxy alkanoate (PHA) blends, have been developed using nonwovens textile technology to …

A Hydrological Analysis Of Switchgrass Land Cover In East Tennessee, Jordan Avery Hayes

Masters Theses

Energy needs and the recent installation of a cellulosic biofuel plant in Vonore, TN have created a demand for switchgrass in East Tennessee. Switchgrass has many strengths such as erosion protection, nutrient removal, and runoff mitigation. The Soil and Water Assessment Tool (SWAT) was selected to model the impact of transitioning traditional crops into switchgrass land cover. Field data was needed to properly calibrate the SWAT model for East Tennessee. The National Resources Conservation Service (NRCS) curve number (CN) was needed for runoff calibrations. This value was determined by both standard NRCS methods as well as an asymptotic method. The …

Defining And Modeling Parameters Associated With Double-Planted Areas In Row Crop Production Fields, Brandon Michael Jernigan

Masters Theses

Automatic Section Control (ASC) utilizes current Global Positioning System (GPS) location of a planter and previously planted coverage maps to control individual planter row units, or sections of planter row units, depending on accuracy desired by equipment operators. ASC eliminates double-planting in areas of agricultural fields where planter overlap is unavoidable, such as end rows, point rows, and around internal field obstacles. Due to costs associated with purchasing ASC, farm managers are interested in rate of return on investment, which depends on several factors such as field boundary irregularity, operator response time, and crop yield response to double-planting.

Georeferenced planting …

Fate And Transport Of 17beta-Estradiol Beneath Animal Waste Holding Ponds, Lori A. Gibson

Masters Theses

Steroidal hormones, such as 17beta-estradiol (E2) and its primary metabolite, estrone (E1), are prevalent in animal waste and are a common subject of study due to potential soil, stream, and groundwater contamination. These particular hormones are labeled as Endocrine Disrupting Chemicals (EDCs) because of their developmental effects in reptiles and amphibians. Dairy waste at concentrated animal feeding operations (CAFOs) is typically stored in a waste pond. Even though these waste ponds are regulated to include a soil liner with a minimal hydraulic conductivity to limit leaching, previous studies have traced stream and groundwater contamination from waste ponds. This research included …

Gis-Based Streambank Video Mapping To Determine Erosion Susceptible Areas, Brett Allen Connell

Masters Theses

According to the U.S. Environmental Protection Agency, excess sediment is a significant cause of water quality impairment for rivers (USEPA, 2009). Therefore, determining the areas of river where streambank erosion is the highest should provide valuable information. Considering the amount of funds being spent on river restoration and storm flow retention, there needs to be a more efficient method to document annual conditions, on a watershed scale. Traditional streambank survey methods are limited in total characterized area, time consuming, environmentally intrusive, and expensive. This project describes the development of a Bank Erosion Susceptibility Index (BESI) to map landscape scale, streambank …

The Effects Of Biochar Amendment To Soil On Bioenergy Crop Yield And Biomass Composition, Charles Warren Edmunds

Masters Theses

This thesis research aims to improve the understanding of how pyrolysis of native feedstocks and biochar application to soil can be utilized to improve soil fertility, crop yield, and sequester carbon in the Southeastern U.S. An emphasis was placed on understanding how the pyrolysis conditions and feedstock material influence biochar characteristics and what effects biochar amendment has on soil and plant growth and composition.

Biochars were produced from switchgrass and pine wood feedstocks via fast pyrolysis at 450, 600, and 800 ˚C with a continuous auger pyrolysis system. Switchgrass-derived biochars had higher ash content, and as observed by elemental analysis, …

Analysis Of Georeferenced Sonar-Based Thalweg And Cross-Sectional River Depth Profile Measurements, Kenneth Wray Swinson

Masters Theses

Depth is a physical river characteristic that is important for habitat classification, river health analysis, and hydrologic/hydraulic modeling. Recent studies have shown that sonar can be an accurate way of measuring river depth, when compared to traditional techniques, but more study is necessary. The main objective of this research was to evaluate the utility of the CruzPro ATU120S and the Lowrance LMS-350A sonar depth units as tools for collecting river depth measurements along longitudinal (thalweg) and cross-sectional profiles. This included analyzing and evaluating the georeferenced commercially available sonar units for accuracy, precision, and response time under controlled lab and river …

A Gps-Based Mobility Power Model For Military Vehicle Applications, George William Bozdech

Masters Theses

In recent years, military vehicles have been equipped with hybrid, diesel-electric drives to improve fuel efficiency and stealth capabilities. These vehicles require an accurate estimate of the power duty cycles during distinct operating conditions. To meet this demand, a GPS-based mobility power and duty cycle analysis is one approach to predict the power requirements of on-road and off-road vehicles. The dynamic vehicle parameters needed to estimate the forces developed during locomotion are determined from the GPS tracking data, and these forces include the following: the motion resistance, gravitational, linear inertia, rotational inertia, and aerodynamic drag. The motion resistance force generated …