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Full-Text Articles in Physical Sciences and Mathematics
Toward Understanding The Thermodynamics And Mechanisms Of Actinide Sorption Reactions, Shanna Estes
Toward Understanding The Thermodynamics And Mechanisms Of Actinide Sorption Reactions, Shanna Estes
All Dissertations
The environmental fate of actinides is greatly influenced by interfacial reactions, including sorption onto solid surfaces. Because changes in the primary hydration sphere of the actinide are expected to greatly influence the thermodynamics (i.e., reaction enthalpy and entropy) of these reactions, examining actinide sorption thermodynamics may provide insight into actinide sorption mechanisms. Additionally, examining actinide sorption thermodynamics may enhance the ability to model or predict these reactions in environmental or engineered systems where variable or elevated temperatures are expected. However, few researchers have studied actinide sorption thermodynamics. Therefore, this research examined the thermodynamics of Eu(III) (a trivalent actinide analog), Th(IV), …
Experimental Evidence For Colloid-Facilitated Transport Of Plutonium, Hilary Emerson
Experimental Evidence For Colloid-Facilitated Transport Of Plutonium, Hilary Emerson
All Dissertations
Colloid-facilitated transport of the actinides has been observed previously in the field on the kilometer scale. The objective of this work is to investigate the mechanisms of colloid-facilitated transport with controlled settings and conditions. The experimental work in this dissertation investigates transport of a ternary complex with iron oxide colloids, organic ligands and actinides in the presence of quartz or a natural sandy soil as well as simplified systems building up to the ternary complexes. The first three papers investigate the following: (1) unsaturated transport of iron oxide colloids in a natural sandy soil lysimeter with and without natural organic …
Fast Fission Neutron Detection Using The Cherenkov Effect, Matthew Millard
Fast Fission Neutron Detection Using The Cherenkov Effect, Matthew Millard
All Theses
The Cherenkov effect in optically clear media of varying indices of refraction and composition was investigated for quantification of fast neutrons. The ultimate application of the proposed detection system is criticality monitoring. The optically clear medium, composed of select target nuclei, was coupled to a photomultiplier tube. Neutron reaction products of the target nuclei contained within the optical medium emit beta particles and gamma rays that produce Cherenkov photons within the medium which can be detected. Assessed media include quartz (SiO2), sapphire (Al2O3), spinel (MgAl2O4), and zinc sulfide (ZnS), which were irradiated with un-moderated 252Cf. Monte Carlo N-Particle (MCNP) code …
Anaerobic And Aerobic Biodegradation Of The Oil Dispersant Components 1,2-Propanediol And 2-Butoxyethanol In Seawater, Benjamin Rhiner
Anaerobic And Aerobic Biodegradation Of The Oil Dispersant Components 1,2-Propanediol And 2-Butoxyethanol In Seawater, Benjamin Rhiner
All Theses
Oil spills are a recurring issue associated with fossil fuel consumption. The largest accidental oil spill in the history of the petroleum industry was the Deepwater Horizon explosion and seafloor well blowout, where the Deepwater Horizon oil rig exploded and sank, allowing the well to gush uncontrolled from April 20, 2010, until it was capped on July 15, 2010, releasing an estimated 210,000,000 gallons of oil. Oil dispersants were used in unprecedented quantities during the cleanup response to the spill with a total of 1,840,000 gallons of the dispersant COREXIT being applied. The goal of this research was to evaluate …
An Examination Of Radionuclide Transport In The Vadose Zone Using Field Lysimeters, Michael Witmer
An Examination Of Radionuclide Transport In The Vadose Zone Using Field Lysimeters, Michael Witmer
All Theses
Understanding how radionuclides interact in the subsurface is important for the remediation of contaminated sites, assessment of risk due to radioactive waste disposal, and designing new radioactive waste management strategies. The current understanding of the geochemical behavior of radionuclides in the subsurface and more specifically the vadose zone has been developed through reactive transport modeling supplemented by laboratory experiments. Interactions between radionuclides with the mineral particles and organic matter in the vadose zone can be very complex and while laboratory experiments produce valuable data, few controlled, intermediate scale transport studies have been performed. In order to accurately predict vadose zone …
Adsorption Of Synthetic Organic Chemicals: A Comparison Of Superfine Powdered Activated Carbon With Powdered Activated Carbon, Semra Bakkaloglu
Adsorption Of Synthetic Organic Chemicals: A Comparison Of Superfine Powdered Activated Carbon With Powdered Activated Carbon, Semra Bakkaloglu
All Theses
In literature, manufacturer-supplied powdered activated carbon has been ground to produce submicron particles with mean diameter lower than 1µm for use as an adsorbent during water treatment. Superfine powdered activated carbon (SPAC) can be used for removal of natural organic matter as well as synthetic organic chemicals (SOCs) from water. It has been suggested that SPAC has higher adsorption capacity than powdered activated carbon (PAC) due to larger external surface area and mesopore volume. Another advantage of SPAC over PAC is the faster uptake rate for both NOM and SOC during adsorption owing to small particle size. Therefore, understanding SPAC …