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 …

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 …

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 …