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Heterogeneous Oxidation Of Multi-Component Aqueous Organic Aerosols: The Effect Of Transport Phenomena And Reaction Compartment On Reaction Kinetics., Tadini Wenyika Masaya

Graduate Theses, Dissertations, and Problem Reports (ETD)

The surface-bulk partitioning of small organic molecules in aqueous droplets was investigated using molecular dynamics. The air-particle interface was modeled using a 80-Å cubic water box containing series of organic molecules and surrounded by gaseous OH radicals. The properties of the organic solutes within the interface and the water-bulk were examined at a molecular-level using density profiles and radial pair distribution functions. Molecules containing only polar functional groups such as urea and glucose are found predominantly in the water bulk, forming an exclusion layer near the water surface. Substitution of a single polar group by an alkyl group in sugars …

Lignocellulosic Biomass Derived Activated Carbon For Energy Storage And Adsorption, Changle Jiang

Graduate Theses, Dissertations, and Problem Reports (ETD)

Lignocellulosic biomass has been converted to hierarchical porous carbon materials which possess macro-, meso- and micro-pores. The natural structure of porous lignocellulosic structure was preserved during activation with further developed porosity by the activation. The activated carbon can be well applied to electrochemical double layer capacitor for transportation storage of ions as well as adsorbent materials for metal ion removal from wastewater.

The first chapter of this dissertation presents an introduction of biomass derived carbon and its applications. In the second chapter, both direct and indirect activation methods using carbon dioxide were adopted in this study. The results show that …

A Fluid Inclusion Study Of Acidity In Bedded Halite Of The Larne Halite Member, Triassic Mercia Mudstone Group From The Carnduff 2 Core, County Antrim, Northern Ireland, Lynnette Ann Eichenlaub

Graduate Theses, Dissertations, and Problem Reports (ETD)

The Carnduff 2 core, drilled in 2014 by the Gaelectric Storage Limited Energy Company in County Antrim, Northern Ireland contains Triassic red mudstones and evaporites of the Mercia Mudstone Group. These rocks have been poorly studied in Northern Ireland. However, recent work suggests that they were deposited in an ancient perennial saline lake system. This thesis describes a 591.6 meter core with 92.7% recovery. Fluid inclusion petrography, microthermometry, and laser Raman spectroscopy were conducted on 12 halite beds of the Larne Halite Member to characterize Triassic lake waters.;Chevron and cumulate halite crystals contain abundant unaltered primary fluid inclusions. Most primary …

Developing High Performance And Stable Hetero-Structured Cathodes And Fundamental Understanding Of Oxygen Reduction And Reaction Behavior, Xinxin Zhang

Graduate Theses, Dissertations, and Problem Reports (ETD)

New hetero-structured La2NiO4+delta (LNO)/ (La0.6Sr0.4)0.95Co0.2Fe0.8O3-delta (LSCF) SOFC cathodes have been successfully fabricated by the infiltration technique for long-term stability and oxygen reduction reaction (ORR) kinetic consideration. The current comparative study of LSCF and LNO-infiltrated LSCF shows a significant reduction in polarization resistance by one order of magnitude and a 67% increase in maximum power density by using LNO-infiltrated LSCF cathodes at 750°C in air. The electronic conductivity relaxation (ECR) results demonstrate that the remarkable improved oxygen exchange properties of LNO/LSCF hetero-structured cathodes are attributed to not only the increase of surface reaction area, but also the introduction of LNO surface …

Asymmetric Synthesis Of Sl0101, Cyclitol And Jadomycin, Mingde Shan

Graduate Theses, Dissertations, and Problem Reports (ETD)

The carbohydrate portion of natural products plays a crucial role in biology, such as target binding, solubility, tissue targeting, and membrane transportation. The O'Doherty group has developed a de novo methodology to build the desired functionality and stereochemistry within each sugar, in contrast to the traditional approach using known carbohydrates as starting materials. This methodology relies on a highly diastereoselective palladium(0)-catalyzed glycosylation reaction to control the stereochemistry at the anomeric center and post-glycosylation transformation to introduce the corresponding functionality in the sugar moiety.;Continuing our investigations on the utility of this strategy, we turned our attention to the syntheses of the …

De Novo Asymmetric Synthesis Of Mannopeptimycin-E, Novobiocin And Methymycin Analogues, Sanjeeva Rao Guppi

Graduate Theses, Dissertations, and Problem Reports (ETD)

The carbohydrate portion of the natural products plays a crucial role in biology, such as target binding, solubility, tissue targeting, and membrane transportation. The O'Doherty group use a de novo methodology to build the desired functionality and stereochemistry within each sugar, in contrast to the traditional approach using known sugar isomers as starting materials. Recently, we have developed a practical and highly diastereoselective palladium catalyzed glycosylation reaction to control the stereochemistry at the anomeric center. Continuing, our investigations on the utility of this strategy, we turned our attention to the syntheses of the bioactive carbohydrate-based natural product analogues. The targets …

Influence Of A Thermal Denuder On Diesel Exhaust Particle Size Distributions, Bobby John

Graduate Theses, Dissertations, and Problem Reports (ETD)

Particle size distributions in diesel exhaust were studied using a thermal desorption technique to determine the volatile and non-volatile fractions. A thermal denuder was designed and characterized for optimal operating parameters and its influence on the exhaust chemistries studied using diesel engine exhaust. The study was conducted on a 1992 DDC Series 60 engine mounted on a heavy-duty direct current dynamometer and exercised over steady state and transient cycles. The particle size distributions were recorded upstream and downstream of the denuder maintained at different temperatures to determine the behavior of the volatile fraction. The volatilization technique was also applied to …

Seawater Proteomics: The Recovery, Separation, And Characterization Of Dissolved Proteins In Seawater., Matthew Jacob Powell

Graduate Theses, Dissertations, and Problem Reports (ETD)

Dissolved proteins are important components of high molecular weight marine dissolved organic matter (DOM). Little is known about the sources, transformations, and pathways of marine DOM, and <30% has been characterized at the molecular-level. Advances in proteomics technology have improved our ability to sequence proteins, making dissolved proteins a suitable target for molecular-level characterization. Dissolved proteins are important biomarkers in the oceans, and molecular-level analysis can provide valuable insight into their chemical characteristics, structural modifications, and potential sources. Molecular-level characterization of dissolved proteins in seawater requires a reproducible recovery method with efficient recovery yields and minimal sample losses. The use of surface blocking agents (SBA) to saturate sites of non-specific interactions reduced adsorptive sample losses during recovery of dissolved proteins from artificial seawater by tangential flow ultrafiltration. The SBA pre-treatment resulted in more reproducible recovery yields (∼55–60%) and enhanced initial recovery by 46%. Dissolved proteins recovered from deep and surface seawater samples were separated by gel electrophoresis, revealing the presence of a small number of discrete bands and significant amounts of unresolved background. A proteinase K assay determined that the bands and unresolved background were proteinaceous in nature. Enzymatic digests of the dissolved proteins were analyzed by reversed phase chromatography coupled on-line to a linear trapping quadrupole Fourier transform mass spectrometer (LTQ-FTMS). The peptide MS/MS spectra were searched against non-redundant databases by correlation algorithms, but no positive identifications were made. The peptide tandem mass spectra were directly interpreted by de novo sequencing to generate peptide tags that were used in database searches to develop protein homologue information. The similarity search results revealed two trends for specific classes of proteins observed (membrane/envelope proteins and enzymes) and identified conserved sequences for several multi-species protein homologues. These results demonstrate that there are several different classes of refractory proteins represented in the DOM pool and provide evidence for the presence of dissolved proteins other than bacterial outer membrane proteins. Additionally, an intact protein was extracted from a gel band and analyzed by direct infusion ESI FTMS. The resultant high resolution protein spectrum was deconvoluted to determine the accurate molecular weight of the protein.

Sulfur Chemistry: Structure And Reactivity Of Substituted Thioureas And Aminothiols Of Physiological Importance., Claudius Mundoma

Graduate Theses, Dissertations, and Problem Reports (ETD)

Complex mechanisms of oxidation of selected sulfur compounds by various oxidants are studied. Chapter 1 is an overall introduction to the field of sulfur chemistry with emphasis on chemical reaction dynamics and the biological significance of aminothiols and substituted thioureas. The rest of the dissertation can be divided into 3 parts based on the type of information obtained from the reaction systems studied. Chapters 2 gives an overview of most of the experimental methods used to come up with a reasonable answer to a given kinetics problem. Chapters 3 and 4 form the basis of the first part in which …