Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 26 for “"photochemical processes"”.
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Effects of silver nanoparticles on photochemical processes focusing on luminol chemiluminescence
… Their effects on enhancing or quenching the photochemical processes of tryptophan fluorescence, a ruthenium complex decay constant and chemiluminescence of luminol and ferricyanide, were studied. The tryptophan fluorescence was slightly enhanced by smaller nanoparticles and showed slight …
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Tracking and Exploiting Charge Carrier Movement and Photochemical Processes in Light-Harvesting Energy Materials
… yet a fundamental understanding of degradation processes, including the specific sites at which failure mechanisms occur, is lacking. Here, multimodal microscopy techniques are utilised to show that nanoscale defect clusters, which are associated with phase impurities, are sites at which …
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Photochemical processes in engineered aquatic systems for remediation of per- and polyfluoroalkyl substances and algae cultivation
Photochemical processes drive many important reactions in environmental engineering applications, ranging from engineered treatment processes (e.g., micropollutant removal) to natural biogeochemical processes (e.g., nutrient cycling). This thesis investigates (1) the application of a UV-sulfite …
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The ground and excited state molecular structure of model systems undergoing photochemical processes and the characterization of active agents by means of vibrational spectroscopy and theoretical calculations
… investigations on model systems undergoing photochemical processes and pharmaceutically active compounds, respectively. Infrared (IR) and Raman spectroscopy were applied for the characterization of the ground state molecular structure. Moreover, resonance Raman (RR) spectra contain …
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Quantum chemical investigation of electron delocalization patterns during photoexcitation in Fischer carbene complexes: a theoretical study
… understanding of various photophysical and photochemical processes, including those that occur during light-harvesting in various solar energy devices. This work presents the novel application of a recently developed quantum chemical theory, the Fragment, Atomic, Localized, Delocalized and …
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Photochemical transformation of particulate organic carbon and its impact on mercury cycling in aqueous systems
… australis ("common reed"), and examined how photochemical processes impact Hg adsorption through chemical alteration of POM. Mercury adsorption to irradiated and non-irradiated POM was examined through performing isotherm experiments, using an environmentally-relevant range of Hg …
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I. Luminescence Spectroelectrochemistry in Thin Layer Cells. Ii. Kinetics of Mediated Oxidation at a Polymer Modified Electrode
… n and E('o)', despite the intrusion of photochemical processes in the test system. In addition, the luminescence mode experiment was found to be a useful probe of quenching behavior.
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Observations of Aromatic Oxidation Products in Southeast Asia
… concentrations based on precursor emissions, photochemical processes, and highlights the significant role of aromatic hydrocarbons in the formation of secondary pollutants like PANs and VOCs. The study also presents the first atmospheric detection of C₈-PAN, attributed to the oxidation of …
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Direct and indirect photoreactions of chromophoric dissolved organic matter : roles of reactive oxygen species and iron
Photochemical transformations of chromophoric dissolved organic matter (CDOM) are one of the principal processes controlling its fate in coastal waters. The photochemical decomposition of CDOM leads to the formation of a variety of biologically available carbon substrates. Photomineralization of …
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Tropospheric composition of organohalogens and alkyl nitrates: tropical and temperate case studies
… data are presented from the Oxidant and Particle Photochemical Processes (OP3) project, conducted in Borneo, 2008. Controlled experiments of temperate vegetation were also conducted to assess the emission of methyl halides from crop plants. Methyl halide results from OP3 contradict current …
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Development, Validation, and Application of Methods for High Time-Response Measurement of Gaseous Atmospheric Chlorinated Species
… in the high irradiance days indicated two photochemical processes; (1) morning time photolysis of Cl precursors, and (2) midday formation of nitric acid followed by acid displacement onto chloride (Cl) containing aerosols. A box model used measured HCl to estimate nitryl chloride mixing …
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Tropospheric composition of organohalogens and alkyl nitrates: tropical and temperate case studies
… data are presented from the Oxidant and Particle Photochemical Processes (OP3) project, conducted in Borneo, 2008. Controlled experiments of temperate vegetation were also conducted to assess the emission of methyl halides from crop plants. Methyl halide results from OP3 contradict current …
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Mechanistic, sensitivity, and uncertainty studies of the atmospheric oxidation of dimethylsulfide
… from multiple uncertain chemical and non-photochemical processes. The DMS oxidation mechanism is quantitatively assessed using a one-dimensional column model constrained by high-frequency aircraft measurements from the
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Functional studies on the extrinsic proteins of Photosystem II
… protein efficiently complemented all of the photochemical defects observed in the psbo1 mutant. Additionally, this study established a new method to isolate PS II core complex in higher plants which can be used for biochemical and biophysical analysis. The psbR mutant was screened and …
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Photoinitiated Dynamics of Cluster Anions via Photoelectron Imaging and Photofragment Mass Spectrometry
… of the solvent in controlling the outcomes of photochemical processes. Interaction of light with cluster anions can potentially lead to cluster photodissociation in addition to photodetachment. We investigate these competing processes by means of photoelectron imaging spectroscopy combined with …
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Control of Network Topology in Photopolymer Networks for Additive Manufacturing
… as well as the material systems and photochemical processes that enable additive manufacturing. An emphasis is placed on work done to regulate free radical polymerization via addition-fragmentation chain transfer (AFCT) and reversible addition-fragmentation chain transfer (RAFT), and …
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Cycling of Iron and Manganese (Oxyhydr)oxides in the Presence of Organic Matter
… to improve our understanding of microbial and photochemical processes governing Fe/Mn cycling and how the specific mineralogy of Fe/Mn oxides influences these processes. In Chapter 1, we determine the influence of iron oxide mineralogy on methanogenesis using sediment from Upper Mystic Lake …
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Fundamentals of Excess Electron Transport in Biologically Relevant Systems
… is governed by both direct and indirect photochemical processes. The Rokita lab previously determined that charge transport from surrounding DNA sequences affect the accumulation of UV-induced thymine dimers in DNA. This dissertation focuses on the variable efficiency of both direct and …
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Hydrogen peroxide in the Halls Brook Holding Area, a small meromictic lake
A study of hydrogen peroxide and the processes that control its concentration was carried out at the Halls Brook Holding Area (HBHA) between May 1997 and June 1998. HBHA is a small meromictic lake that receives groundwater contaminated by an adjacent Superfund site. Inflow and outflow rates and …
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Investigating the impacts of entrainment on nucleation scavenging of black carbon particles through particle-resolved simulations
… of semi-volatile substances, coagulation, and photochemical processes, termed aging, the mixing state of the particles change can further change. During the aging processes, initially hydrophobic black carbon become hydophilic, and can then act as cloud condensation nuclei. Under a high …
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