Physical Sciences and Mathematics Commons^™

Fabrication And Analysis Of Polymeric Nanocomposites From Cellulose Fibrils, Qingzheng Cheng

Doctoral Dissertations

A novel process using high-intensity ultrasonication (HIUS) was developed to isolate fibrils from cellulose fibers. The geometrical characteristics of the fibrils were investigated using polarized light microscopy (PLM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Results show that small fibrils with diameter ranging from about thirty nanometers to several micrometers were peeled from the fibers. The degree of fibrillation of the fibers was significantly increased. The crystallinities or molecular structures of most of the cellulose materials were changed by HIUS treatment.

To evaluate the fibrils degradation by HIUS, a method using AFM was modified and developed to measure …

Parametric And Non-Parametric Regression Tree Models Of The Strength Properties Of Engineered Wood Panels Using Real-Time Industrial Data, Timothy Mark Young

Doctoral Dissertations

The forest products industry is undergoing unprecedented change from international competition, increasing fiber costs, rising energy prices and falling product prices. Competitive businesses have the key ability to adapt quickly to change through improved knowledge. Among adaptations to change are better product development, improved process efficiency and superior product quality. This dissertation is directly related to improving the knowledge of forest products manufacturers by investigating data mining (DM) methods that improve the ability to quantify causality of sources of variation. A contemporary DM method related to decision theory is decision trees (DTs). DTs are designed for heterogeneous data and are …

Bacterial Source Tracking In An Eastern Tennessee Stream Using Bacteroides Host Associated Real-Time Polymerase Chain Reaction Assays, Ryan Michael Ragsdale

Masters Theses

A bacterial source tracking study using Bacteroides host associated real-time PCR assays was performed to determine the sources of fecal contamination in Pond Creek (HUC 06010201013). Pond Creek, located in the Ridge and Valley physiographic region in Eastern Tennessee, is a 303(d) listed stream that fails to meet water quality standards for pathogens. Water samples and discharge were measured monthly at eight locations from November 2005 to November 2006. Grab samples were analyzed for several chemical parameters and for microbial fecal indicator organisms, namely Bacteroides spp., Escherichia coli, and Enterococcus. The objectives of the study were to quantify total, …

Stream Restoration Assessment Of Abrams Creek In The Great Smoky Mountains National Park: Management Implications And Comparison Of Empirical And Analytical Physical Assessment Approaches, Daniel L. Carter

Masters Theses

Natural resource managers in the Great Smoky Mountains National Park requested the assistance of the University of Tennessee Department of Civil and Environmental Engineering to assess Abrams Creek for potential stream restoration needs. A presumed, unstable study reach and a stable reference reach were identified on Abrams Creek in Cades Cove. Chemical, biological and physical assessments were completed on Abrams Creek in order to evaluate ecological health and channel stability of the stream. Water quality and ecological (fish and habitat surveys) data acquired by National Park Service, Tennessee Valley Authority and the University of Tennessee were assessed. The physical assessment …

Effects Of Environmental Stress On Growth, Yield, And Flavonolignan Content In Milk Thistle Silybum Marianum L. Gaertn, Amy Renae Belitz

Masters Theses

Four experiments were performed in a greenhouse or growth chamber to study the quantity and quality of flavonolignans in response to environmental stress in milk thistle (Silybum marianum L., Gaertn.). A preliminary experiment was conducted in spring 2004 to study effects of leaf harvests on growth, development, and flavonolignan content in milk thistle seeds. Taxifolin, a component of silymarin and precursor to flavonolignans, was significantly reduced due to leaf harvest treatments.

The weedy nature (sporadic germination) of Silybum made germinating enough plants for experimentation problematic. Initial germination studies to determine imbibition and pre-chilling requirements were inconclusive due to heavy …

Impact Of Crop Rotations And Winter Cover Crops On Vegetative Cover, Aboveground Biomass, And Soil Organic Matter Under No-Till In Western Tennessee, Nicholas Phillip Ryan

Masters Theses

We investigated, under long-term no-till in western Tennessee, the effects of rotating the low-input crops cotton and soybeans with the high-input crop corn, compared to continuous monocultures of cotton and soybeans, and of using the winter cover crops (WCCs) winter wheat and hairy vetch, compared to winter fallow, on key indicators of soil health concerning vegetative cover and labile SOM. The line-transect method was used to measure percent vegetative cover. Dry weight of surface crop residue and aboveground living plant biomass (WCCs and winter weeds) was obtained. The living plant biomass was analyzed for carbon (C) and nitrogen (N) by …

A Team-Based Approach To Social Learning Research In Natural Resource Management, Jonah Malachai Fogel

Doctoral Dissertations

This thesis responds to the need to quantify social learning and its outcomes as it relates to natural resource management. Social learning enables individuals engaging in collective action to understand each other’s perspectives, encourages integration of diverse knowledge bases, and the creation of new knowledge (Keen, Brown, & Dyball, 2005). However, the concept currently lacks a clear operational definition in natural resource management. The lack of an operational definition for social learning has stymied attempts to validate its espoused ability to improve civic discourse and, ultimately, resource governance (Pahl-Wostl & Hare, 2004). This report is composed of three papers that …

Characterizing Episodic Stream Acidity During Stormflow In The Great Smoky Mountains National Park, Edwin Bradley Deyton

Masters Theses

Episodic stream acidification occurs as storm events temporarily reduce acid neutralizing capacity (ANC) and pH. Stream acidification is suspected to have damaging effects on the health of aquatic ecosystems and biota. The objectives of this research are to 1) characterize stream baseflow and stormflow chemistries in three watersheds in the Great Smoky Mountains National Park (GRSM), 2) understand potential mechanisms responsible for episodic acidification, and 3) understand the relationship between storm event magnitude, antecedent soil moisture condition, and the stream’s pH response. Three remote, forested, high-elevation streams (Middle Prong, Ramsey Prong, and Eagle Rocks Prong) were selected in the Middle …

Measuring The Value Of Air Quality: Application Of The Spatial-Hedonic Model, Seung Gyu Kim

Masters Theses

The value of air quality improvement following the 1990 Clean Air Act Amendments is estimated at the county level in the lower 48 United States. This study applies a hedonic model to assess the economic benefits of air quality improvement using an instrumental variable approach that combines geographically weighted and spatial autoregression methods to account for spatial heterogeneity and spatial autocorrelation. Positive amenity values of improved air quality are found in five major clusters of areas across Eastern Kentucky and most of Georgia around Southern Appalachian area, the State of Illinois, on the border of Oklahoma and Kansas, on the …

Golden-Winged Warbler (Vermivora Chrysoptera) Demographics And Habitat Use And The Potential Effects Of Land Use Change On Golden-Winged And Cerulean Warblers (Dendroica Cerulea) In The Cumberland Mountains Of Tennessee, Lesley Penfield Bulluck

Doctoral Dissertations

The golden-winged warbler (Vermivora chrysoptera) is an early successional Nearctic-Neotropical migrant songbird undergoing population declines range-wide. The Cumberland Mountains contain one of the southernmost populations where goldenwingeds occur in relatively high densities on old reclaimed surface mines. The three objectives of this research were to (1) describe the basic demography and habitat use of this population, (2) compare the demography of the Cumberland population to a population in Ontario, and (3) to model alternative land use scenarios and the impacts on both the golden-winged warbler and the cerulean warbler (Dendroica cerulean), another declining Nearctic-Neotropical migrant that …

Ecological Indicator Development, Integration And Knowledge Mapping, Aaron Dean Peacock

Doctoral Dissertations

The overall goals of this project were: (1) to develop a microbiological ecological indicator that would describe military land disturbance, (2) integrate previously collected ecological indicator data from five separate research teams, and (3) produce knowledge maps with the resulting information that illustrates how the selected indicators are involved in ecosystem processes. To address goal one, soil samples were obtained from four levels of military traffic (reference, light, moderate, and heavy) with an additional set of samples taken from previously damaged areas. Using the soil microbial biomass and community composition as ecological indicators, reproducible changes showed increasing traffic disturbance decreases …

Evaluation Of Forest Management To Improve Breeding Habitat For Songbirds In Oak-Hickory Forests At Tennessee National Wildlife Refuge, Benjamin Stephen Thatcher

Doctoral Dissertations

Partners in Flight (PIF) recommends using silviculture to improve breeding habitat conditions for migrant landbirds. Alternative thinning treatments may benefit priority landbird species by increasing structural complexity in second-growth forests. However, the effects of thinning on landbird populations in oak (Quercus spp.)-hickory (Carya spp.) forests have not been experimentally demonstrated. I used a randomized and replicated large-scale manipulative experiment to evaluate the effects of thinning (i.e., crown-release and gap creation) on forest habitat characteristics and avian populations at the Tennessee National Wildlife Refuge. I collected data during 2001 (pre-treatment) and from 2002 to 2005 (1 to 4 years …

Seasonal Variations In Fish Assemblages Of Small Warmwater Streams In Four Southeastern National Parks, Joseph Carl Zimmerman

Masters Theses

Small warm-water streams in the southeastern United States experience significant differences in temperature, as well as changes in physical parameters due to seasonal fluctuations. It has been generally thought that fish assemblage patterns change as a direct result of these seasonal variations. This study was designed to determine the effects of variable flow regimes on fish species composition, diversity, and abundance. Eight small warm-water streams in four national parks (Chickamauga and Chattanooga National Military Park, Fort Donelson National Battlefield, Abraham Lincoln Birthplace National Historic Site, and Russell Cave National Monument) were sampled May-June 2005 for the summer trials, October-November 2005 …