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 34 for “"UV absorbance"”.
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Identification and quantification of natural organic matter in the Windhoek operating company water treatment plant in Windhoek, Namibia
… Temperature, pH, organic content, nitrates, UV absorbance at 254 nm (UV254) and specific UV absorbance (SUVA) measurements were performed on the day of sampling. The molecular weight distribution of the organic fractions was determined using high pressure size exclusion chromatography (HPSEC) …
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Evaluation of treatment alternatives for THM-precursor removal from the Po River and Ni River, Virginia
… (TOC), THM-formation potential (THMFP), color, UV-absorbance and pH. Samples were then treated in a manner similar to that ina typical water treatment plant by bench-scale jar tests and reanalyzed for TOC, THMFP, color and UV-absorbance. The results indicate that the THMFPs of both Po and Ni …
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Two - Stage AnMBR for Removal of UV Quenching Organic Carbon from Landfill Leachates: Feasibility and Microbial Community Analyses
… that can absorb large amounts of ultraviolet (UV) light, greatly reducing the UV transmissivity in wastewater plants using UV disinfection as the final treatment step. This interference with UV disinfection is observed even when landfill leachates constitute a very small fraction (of the order …
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Aromatic Rich Natural Organic Matter Increases Growth and Reduces Nickel Toxicity in a Wild Daphnia Hybrid
… Ni mitigation for those isolates with specific UV absorbance below 19.3 cm2mg-1. Incorporating NOM aromatic content into a predictive model improves the relationship between predicted and measured LC50s by 5%. I demonstrate that structural differences between NOM isolates relating to aromatic …
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Evaluation of activated carbon processes for removing trihalomethane precursors from a surface water impoundment
… not as efficient as the GAC and BAC processes. UV absorbance measured at 254 nm and TOC were found to be good surrogates for THMFP in the GAC column, but not in the BAC column.
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Novel Compounds From Methanogens: Characterization of Component B of the Methylreductase System and Mobile Factor
… mol of aldopentose per mol of component B. The UV absorbance spectrum revealed the presence of two absorbance peaks in component B: one at 267 nm and the other at 233 nm. It was concluded that component B contained a nucleotide moiety.
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Process Analytical Technology in biopharmaceutical manufacturing
… PAT system that acquires light scattering and UV absorbance data to control chromatography during large-scale manufacturing are presented as a case study. The case study follows the methodology to show how a system optimized for a laboratory can be scaled for use in biopharmaceutical …
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Effects of Raceway Pond Water and Nutrient Recycling on Microalgae Production and Harvesting
… soluble chemical oxygen demand, and soluble UV absorbance) of potentially inhibitory substances and of nitrogen and phosphorus concentrations, which would have limited growth if they were too low.</p> <p>After 7 months of continuous operation and 50 cycles of water reuse, the algae …
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Using Coagulation to Enhance the Performance of Filtration at the South Truckee Meadows Water Reclamation Facility
… total suspended solids, electrical conductivity, UV absorbance at 254 nm, and total organic carbon. Seasonal variations of pH, temperature, and turbidity of the water withdrawn from the reservoir were also assessed. From July through September 2016, in-situ water quality monitoring at different …
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A directed evolution design of target specificity and kinetic analysis of conformational transitions in the HhaI methyltransferase /
… of these processes by monitoring associated UV absorbance changes in a chemically unperturbed DNA. These studies for the first time demonstrate that the flipping of the target cytosine and the closure of the catalytic loop in the enzyme occur simultaneously, whereas the covalent activation of …
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Kinetics and Speciation of Brominated Disinfection by -Products During Ozonation
… unit mg C, and was correlated to both Specific UV absorbance (SUVA) and specific phenolic content. The apparent second-order rate constants for the reaction between HOBr and NOM ranged from 3 x 105 to 1.0 x 106 M-1 •s-1. Although preozonation tended to reduce it, the fast reaction component …
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Synthesis and characterization of metallic nanoparticles with photoactivated surface chemistries
… nanoparticles at each step including UV-absorbance, zeta potential, and dynamic light scattering. Different generations of oligomers were synthesized to be used as gold nanorods coating, and each coating was tested and characterized using appropriate techniques. Our two-step coating …
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Photochemically produced reactive species generation by extracellular organic matter sensitizers from Chlamydomonas reinhardtii
… transformation of organic micropollutants in UV and visible light irradiated algae suspensions where photogenerated 1O2 and •OH were detected. The photochemistry in EOM matrices is still largely unknown as well as the impacts of reactive species on cultivation including EOM mineralization, …
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Squaramide-Naphthalimide Conjugates as Potential Self-Assembled Materials and as DNA Binders
… involve various techniques including VT-NMR, UV absorbance time studies, extinction coefficient studies and Scanning Electron Microscopy. Chapter 4 discusses the possible DNA binding ability of the novel synthesised compounds using UV-Vis absorbance, fluorescence and Ethidium Bromide Assays. …
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Impact of operating conditions on thermal hydrolysis pre-treated digestion return liquor
… wastewater treatment plant (WWTP) and introduce UV quenching substances to the wastewater stream when recycled. While there are mature technologies in place to handle the inorganic nitrogen produced due to the thermal pretreatment, organic nitrogen remains a parameter of concern for utilities …
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The large scale understanding of natural organic matter : processes and application
… rapid and reliable monitoring. A model of UV absorbance was tested against freshwaters that were biased towards eutrophic conditions. The results demonstrated the weak absorbing components of algal DOM, and new variable model parameters were introduced, which quantified the contribution of …
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Batch foaming of hot melt extruded excipient/disintegrant/API pharmaceutical formulations and the study of the effects of the resulting cellular structures on API dissolution
… concentration of API is determined through an UV absorbance calibration curve. The result strongly indicates that both disintegrants do accelerate the disintegration. In conclusion, the addition of disintegrant in the HME process formulation, which embeds it in the polymer matrix, is a valid …
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Total N-nitrosamine Precursor Adsorption with Carbon Nanotubes: Elucidating Controlling Physiochemical Properties and Developing a Size-Resolved Precursor Surrogate
… of THM and DHAN precursors leverage metrics from UV absorbance and fluorescence spectroscopy, a TONO precursor surrogate has proved elusive. This is important as measurements of TONO formation potential (TONOFP) require large sample volumes and long processing times, which impairs development of …
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Advanced Technologies for Resource Recovery and Contaminants Removal from Landfill Leachate
… of landfill leachate. The removal of leachate UV-quenching substances (humic, fulvic, and hydrophilic acids) using an MFC and a chemical oxidant (i.e., sodium percarbonate) with a focus on energy production and cost efficiency were also studied. BES treatment can reduce leachate organics …
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THE DETERMINATION OF STABILITY CONSTANTS AND COMPLEXING CAPACITIES OF NATURAL ORGANIC MATTER FOR COPPER (2+), COBALT (2+) AND MANGANESE (2+) BY FLUORESCENCE QUENCHING TITRATION
… showed a statistically significant trend between UV absorbance and C(,L) values.</p>
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