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Full-Text Articles in Physical Sciences and Mathematics

Technical Evaluation Of Hardwood Biorefinery Using The "Near-Neutral" Hemicellulose Extraction Process, Haibo Mao Dec 2007

Technical Evaluation Of Hardwood Biorefinery Using The "Near-Neutral" Hemicellulose Extraction Process, Haibo Mao

Electronic Theses and Dissertations

A technical analysis was performed for a new process that produces ethanol and acetic acid from hardwood in addition to bleached hardwood Kraft pulp. The new process, termed the "near neutral" hemicellulose extraction process, involves the extraction of wood hemicellulose using green liquor prior to conventional Kraft pulping. This thesis assumes that the new process is located at an existing kraft pulp mill. Ancillary unit operations in the process include hydrolysis of the extracted carbohydrates using sulfuric acid, filtration of the extract to remove lignin that was extracted with the carbohydrates, liquid-liquid extraction of acetic acid and by-product furfural, liming …


A Computational Chemistry Study Of Spin Traps., Jacob Fosso-Tande Aug 2007

A Computational Chemistry Study Of Spin Traps., Jacob Fosso-Tande

Electronic Theses and Dissertations

Many defects in physiological processes are due to free radical damage: reactive oxygen species, nitric oxide, and hydroxyl radicals have been implicated in the parthenogenesis of cancer, diabetes mellitus, and rheumatoid arthritis. We herein characterize the phenyl-N-ter-butyl nitrone (PBN) type spin traps in conjunction with the most studied dimethyl-1-pyrroline-N-oxide (DMPO) type spin traps using the hydroxyl radical. In this study, theoretical calculations are carried out on the two main types of spin traps (DMPO and PBN) at the density functional theory level (DFT). The energies of the optimized structures, hyperfine calculations in gaseous and aqueous phases of the spin traps …


Kinetics And Mechanism Of Oxygen Delignification, Yun Ji May 2007

Kinetics And Mechanism Of Oxygen Delignification, Yun Ji

Electronic Theses and Dissertations

Considerable research has been conducted into the kinetics and selectivity of the oxygen delignification process to overcome limitation in its use. However most studies were performed in a batch reactor whereby the hydroxide and dissolved oxygen concentrations are changing during the reaction time in an effort to simulate tower performance in pulp mills. This makes it difficult to determine the reaction order of the different reactants in the rate expressions. Also the lignin content and cellulose degradation of the pulp are only established at the end of the experiment when the sample is removed from the batch reactor. To overcome …


Modification Of Semi-Metal Oxide And Metal Oxide Powders By Atomic Layer Deposition Of Thin Films, Mark Q. Snyder May 2007

Modification Of Semi-Metal Oxide And Metal Oxide Powders By Atomic Layer Deposition Of Thin Films, Mark Q. Snyder

Electronic Theses and Dissertations

This work describes two methods of modifying, and the subsequent characterizing of, oxide nanopowders. The first method, atomic layer deposition, or ALD, is a series of surface-limited reactions that are repeated to deposit a thin, inorganic film on the surface of the nanopowder. Deposition of a thin film is a useful method to alter the surface properties of a material while retaining its bulk properties. Part of this thesis concerns the understanding of the growth mechanism of thin film titanium nitride (a material known for thermal and chemical stability as well as electronic conductivity) on silica through the ALD process. …


Remediation Of Heavy Metal Contamination In Sediments: Application Of In Situ Treatment Utilizing Emulsified Liquid Membrane An, Deborah Maxwell Jan 2007

Remediation Of Heavy Metal Contamination In Sediments: Application Of In Situ Treatment Utilizing Emulsified Liquid Membrane An, Deborah Maxwell

Electronic Theses and Dissertations

Heavy metal contamination of soils, sediments and groundwater presents an ongoing source of hazardous and persistent environmental pollution. How best to remediate these contaminants is the impetus of continuing research efforts. Methods include containment, ex situ and in situ techniques. A successful in situ method utilizing a combination of emulsified liquid membranes, ELM, and zero-valent metal, ZVM, and bimetals has demonstrated impressive heavy metal reduction in 100 ppm solutions of Cd, Cu, Ni, Pb, Cr and U. This promising in situ method has been employed by the Industrial Chemistry Laboratory at the University of Central Florida and it has demonstrated …


Synthesis Of Novel Aziridine Derivatives Of Podocarpic Acid, Stephen Rhoden Jan 2007

Synthesis Of Novel Aziridine Derivatives Of Podocarpic Acid, Stephen Rhoden

Electronic Theses and Dissertations

Podocarpic acid (a diterpenoid resin acid extracted from the Podocarpacea specie of plants) has shown cytotoxicity against carcinoma of the nasopharynx. Since this discovery has been made, research has been performed in order to alter the structure of the resin acid so as to increase the anticancer activity. The carboxylic acid and phenol functional groups, which are present in podocarpic acid, make it possible to synthesize new derivatives selectively at the C-15, C-13, and C-7 positions as well as by substitution of the phenol hydroxyl group. Thus numerous derivatives can be prepared, in high yield, for the purpose of investigating …


Analytical Potential Of Polymerized Liposomes Bound To Lanthanide Ions For Qualitative And Quantitative Analysis Of Proteins, Marina Santos Jan 2007

Analytical Potential Of Polymerized Liposomes Bound To Lanthanide Ions For Qualitative And Quantitative Analysis Of Proteins, Marina Santos

Electronic Theses and Dissertations

One of the intriguing features of biological systems is the prevalence of highly selective and often very strong interactions among different cellular components. Such interactions play a variety of organizational, mechanical, and physiological roles at the cellular and organism levels. Antigen-antibody complexes are representative examples of highly selective and potent interactions involving proteins. The marked specificity of protein-antibody complexes have led to a wide range of applications in cellular and molecular biology related research. They have become an integral research tool in the present genomic and proteomic era. Unfortunately, the production of selective tools based on antigen-antibody interactions requires cumbersome …


Analytical Evaluation Of The Fluorescence Characteristics Of Metabolites Of Polycyclic Aromatic Hydrocarbons At Room, Liquid Nitrogen And Liquid Helium Temperatures, Keerthika Vatsavai Jan 2007

Analytical Evaluation Of The Fluorescence Characteristics Of Metabolites Of Polycyclic Aromatic Hydrocarbons At Room, Liquid Nitrogen And Liquid Helium Temperatures, Keerthika Vatsavai

Electronic Theses and Dissertations

Although environmental monitoring of polycyclic aromatic hydrocarbons (PAH) is an essential step to prevent human exposure to contaminated sites, it provides little information on the actual human uptake and subsequent risks. To this end, urine analysis of short-term biomarkers such as PAH metabolites fill an important niche. The general approach follows the sequence of urine hydrolysis, sample clean-up and pre-concentration, chromatographic separation and determination. Whereas chromatographic methods are based on well established laboratory techniques, the development of easy-to-use, cost-effective and large sample throughput techniques is becoming increasingly relevant to investigate adverse PAH effects on large human populations. This thesis compares …


Advances In Fire Debris Analysis, Mary Williams Jan 2007

Advances In Fire Debris Analysis, Mary Williams

Electronic Theses and Dissertations

Fire incidents are a major contributor to the number of deaths and property losses within the United States each year. Fire investigations determine the cause of the fire resulting in an assignment of responsibility. Current methods of fire debris analysis are reviewed including the preservation, extraction, detection and characterization of ignitable liquids from fire debris. Leak rates were calculated for the three most common types of fire debris evidence containers. The consequences of leaking containers on the recovery and characterization of ignitable liquids were demonstrated. The interactions of hydrocarbons with activated carbon during the extraction of ignitable liquids from the …


Singlet Oxygen Generation Using New Fluorene-Based Photosensitizers Under One- And Two-Photon Excitation, Stephen James Andrasik Jan 2007

Singlet Oxygen Generation Using New Fluorene-Based Photosensitizers Under One- And Two-Photon Excitation, Stephen James Andrasik

Electronic Theses and Dissertations

Molecular oxygen in its lowest electronically excited state plays an important roll in the field of chemistry. This excited state is often referred to as singlet oxygen and can be generated in a photosensitized process under one- or two-photon excitation of a photosensitizer. It is particularly useful in the field of photodynamic cancer therapy (PDT) where singlet oxygen formation can be used to destroy cancerous tumors. The use of two-photon activated photosensitizers possesses great potential in the field of PDT since near-IR light is used to activate the sensitizer, resulting in deeper penetration of light into biological tissue, less photobleaching …


Analysis Of Mitochondrial Dna Coding Region Snps By Pyrosequencing, Kyle Robert Carl Parker Jan 2007

Analysis Of Mitochondrial Dna Coding Region Snps By Pyrosequencing, Kyle Robert Carl Parker

Electronic Theses and Dissertations

To date, the use of mitochondrial DNA in forensic analysis has relied on the presence of variations in the control region to differentiate between samples. One problem that this analysis has shown is the occurrence of common Haplogroup H haplotypes or identical sequences. Thus, there is a need to enhance the distinguishing power of this type of analysis. One option has been to investigate the mitochondrial coding region for polymorphisms that could differentiate between samples with identical control region haplotypes. The goal of this study has been to identify polymorphic coding region sites for development in a Pyrosequencing assay that …


Discrimination Of Forensic Trace Evidence Using Laser Induced Breakdown Spectroscopy, Candice Bridge Jan 2007

Discrimination Of Forensic Trace Evidence Using Laser Induced Breakdown Spectroscopy, Candice Bridge

Electronic Theses and Dissertations

Elemental analysis in forensic laboratories can be tedious and many trace evidence items are not analyzed to determine their elemental composition. Presently, scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDS) is the primary analytical tool for determining the elemental composition of trace evidence items. However, due to the time it takes to obtain the required vacuum and the limited number of samples that can be analyzed at any one time, SEM-EDS can be impractical for a high volume of evidence items. An alternative instrument that can be used for this type of analysis is laser ablation inductively coupled plasma mass spectrometry …


Two-Photon 3d Optical Data Storage Via Fluorescence Modulation Of Fluorene Dyes By Photochromic Diarylethenes, Claudia Corredor Jan 2007

Two-Photon 3d Optical Data Storage Via Fluorescence Modulation Of Fluorene Dyes By Photochromic Diarylethenes, Claudia Corredor

Electronic Theses and Dissertations

Three-dimensional (3D) optical data storage based on two-photon processes provides highly confined excitation in a recording medium and a mechanism for writing and reading data with less cross talk between multiple memory layers, due to the quadratic dependence of two photon absorption (2PA) on the incident light intensity. The capacity for highly confined excitation and intrinsic 3D resolution affords immense information storage capacity (up to 1012 bits/cm3). Recently, the use of photochromic materials for 3D memory has received intense interest because of several major advantages over current optical systems, including their erasable/rewritable capability, high resolution, and high sensitivity. This work …


Forensic Analysis Of C-4 And Commercial Blasting Agents For Possible Discrimination, Katie Steele Jan 2007

Forensic Analysis Of C-4 And Commercial Blasting Agents For Possible Discrimination, Katie Steele

Electronic Theses and Dissertations

The criminal use of explosives has increased in recent years. Political instability and the wide spread access to the internet, filled with "homemade recipes," are two conjectures for the increase. C-4 is a plastic bonded explosive (PBX) comprised of 91% of the high explosive RDX, 1.6% processing oils, 5.3% plasticizer, and 2.1% polyisobutylene (PIB). C-4 is most commonly used for military purposes, but also has found use in commercial industry as well. Current methods for the forensic analysis of C-4 are limited to identification of the explosive; however, recent publications have suggested the plausibility of discrimination between C-4 samples based …