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 19 of 19 for “"dissolution-precipitation"”.
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Extraction of Additives from Polystyrene and Subsequent Analysis
… is demonstrated and compared to traditional dissolution/precipitation extractions. The purpose of the study was twofold: 1) the development of a high performance liquid chromatography (HPLC) method(s) for the additives and 2) the determination of the viability of supercritical fluid …
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Computer modelling of the chemical speciation in seawater
… insight into the chemical processes controlling dissolution, precipitation, redox levels and coordinative interactions in surface seawater. In order to accomplish this task a relatively extensive database consisting of about 580 complexation equilibria arising from 32 inorganic and 10 organic …
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Chemical and physical effects of interaction between oilfield chemicals and formation rocks and integration with sand failure prediction models.
… prediction models. Results clearly show that a dissolution/precipitation reaction took place, weakening the reservoir grain fabrics and reducing the geomechanical strength, which in turn causes sand failure/production. This work has established that volume fraction and porosity change are …
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Hydrogen Interactions in the Subsurface Geological Formations: Molecular and Biogeochemical Perspectives
… for the determination of hydrogen loss, mineral dissolution-precipitation, pH variations, mineral saturation changes, and growth of bacteria under an abiotic environment with specified geological conditions. To enhance predictive capabilities and support future assessments, machine learning, …
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Experimental and theoretical studies of reactive transport processes in soluble porous rocks
… processes involve fluid flow and reactions (dissolution, precipitation, and pressure solution) driving the evolution of the rock-fluid systems, which may result in favorable processes such as increased oil production by reservoir acid stimulation, or undesired processes such as caves and …
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Carbon Cycling Dynamics Inferred from Carbon Isotope Sourcing in a Mid-Latitude Karst-Influenced River
… dissolving carbonate bedrock and carbonate dissolution/precipitation reactions contributed 31% and 11%, respectively. The more carbonate-dominated downstream catchment also was influenced greatly by soil respiration (35%). Due to the more pronounced levels of carbonate bedrock, carbonate …
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In Situ Liquid Cell Transmission Electron Microscopy Studies of Pathological Biomineralization
… pathways that govern stability, growth, and dissolution during crystallization. In-situ GLC-TEM provides an excellent model for confinement during biomineralization and is supported by graphene’s unique properties that enable imaging at the nanoscale. The findings highlight the complexity of …
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Quantitative Analysis of Additives in Low Density Polyethylene Using On-line Supercritical Fluid Extraction /Supercritical Fluid Chromatography
… extraction methods, which involve dissolution/precipitation, are time-consuming, uneconomical, and the recoveries are significantly lower than 90%. In recent years, analysis with supercritical fluids (SFs) has emerged as an alternative analytical technique because SFs afford higher …
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Quantitative Analysis of Antioxidants from High Density Polyethylene (HDPE) by off-line Supercritical Fluid Extraction Coupled High Performance Liquid Chromatography
… for polymer additive(s), such as, Soxhlet or dissolution / precipitation are labor intensive, time consuming, expensive, and the optimal recovery is significantly less than 90 percent. In addition, a large amount of solvent , such as toluene or decalin, must be eliminated in order to …
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The aqueous aragonite to calcite transformation: rate, mechanisms, and its role in the development of neomorphic fabrics
… transformation regimes, macroscale (passive dissolution), mesoscale (chalk zone), and microscale (thin film) dissolution-precipitation, are proposed to explain the variability in observed diagenetic calcite textures. These are differentiated by the surface area/solution ratio in the reaction …
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Kinetics of phase transformations in lithium-sulfur batteries
… rate capability resulting in part from a complex dissolution-precipitation mechanism which produces electronically insulating end members S₈ and Li₂S. Few studies have heretofore been performed on rate-limiting mechanisms in Li-S batteries, which must be elucidated in order to inform rational …
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Effect Of Source Water Blending On Copper Release In Pipe Distribution System: Thermodynamic And Empirical Models
… (Cu(OH)2) on the top surface. In terms of dissolution/precipitation mechanism controlling the copper concentration in bulk solution, cupric hydroxide thermodynamic model was developed. (2) Theoretical thermodynamic models were developed to predict the copper release level quantitatively …
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Experimental investigation of the fluid driven carbonation of serpentinites and spinel-peridotites: implications for the carbon and trace element cycle in the forearc region of the mantle wedge
… which likely occurs via an interface coupled dissolution precipitation mechanisms. Carbonation occurs as soon as the COH-fluid is in contact with primary silicates. Carbonation is fast and completed within <1 h of the experiments using powdered serpentinite and within <96 h using serpentinite …
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Experimental investigation of the fluid driven carbonation of serpentinites and spinel-peridotites: implications for the carbon and trace element cycle in the forearc region of the mantle wedge
… which likely occurs via an interface coupled dissolution precipitation mechanisms. Carbonation occurs as soon as the COH-fluid is in contact with primary silicates. Carbonation is fast and completed within <1 h of the experiments using powdered serpentinite and within <96 h using serpentinite …
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Mineral, fluid and thermal evolution in veins from late orogenic coal basins of the Cantabrian Zone (Variscan, NW Spain)
… dolomite precipitated. Materials for mineral precipitation were derived locally from the detrital fraction within the Stephanian rocks,and transported into solution by advection of large volumes of gas (CH4 -CO2) and water formed in response to progressive maturation of the coal. Stage 2 also …
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The reactivity of ferric (hydr)oxides towards dissolved sulphide
… as iron sulphide. During the reductive dissolution adsorbed species like arsenic may be released from the oxide surfaces to solution. Furthermore, the generation of ferrous iron in ground water systems, their transport through the groundwater-surface water interface, and subsequent iron …
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PCO2 EFFECTS ON THE PRODUCTION OF PELAGIC BIOGENIC CARBONATE AND OCEAN CHEMISTRY: A CASE HISTORY FROM THE CRETACEOUS.
… between OJP volcanism, weathering, carbonate dissolution/precipitation and organic matter burial. Moreover, O stable isotopes concurred in the reconstruction of paleotemperatures. Ocean changes prior to, during and at the end of OAE1a comprise: deep-water acidification, calcite-lysocline and …
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The effect of radiation damage by fission fragments on the structural stability and dissolution of the UO2 fuel matrix
… damage on the structural integrity and matrix dissolution of uranium dioxide in water. Radiation damage similar to fission damage was created by irradiating bulk undoped and doped ‘SIMFUEL’ disks of UO2, undoped bulk CeO2 and thin films of UO2 and CeO2 with high energy Xe and U ions. The UO2 …
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The design and development of hydrogen isotope extraction technologies for a limit-style liquid lithium loop
… a plasma environment, meaning enhanced hydrogen dissolution was not witnessed at ion energies relevant to these experiments. The presence of a plasma, however, did appear to enhance absorption rates above and beyond what was capable with hydrogen gas alone. During these tests, hydrogen evolution …