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Soil 14CO2 Source Apportionment for Biodegradation in Contaminated Soils in Permafrost Climates: A Novel Technique for Rapid Sample Collection by Barium Carbonate PrecipitationReynolds, Lindsay 01 May 2019 (has links)
The rate of biodegradation of hydrocarbon contaminated soils can be studied using the radiocarbon (14C) content of CO2 efflux from the ground surface over an impacted area.14C is used as a tracer to distinguish modern 14C CO2 from natural respiration processes and 14C depleted CO2 derived from petroleum degradation. Studies have shown that this analysis provides reliable, quantifiable data and an effective means of correcting for background CO2 which may present some natural depletion from older subsurface organics. The study area for this project is a remote community in Northern Yukon where organic rich sediments overlying continuous permafrost are contaminated by diesel oil. An objective of this study was to evaluate the use of 14C to quantify background CO2 in permafrost soils with abundant, older labile organics. A second objective was to test a new sampling technique to facilitate sample shipment from remote sites, which traps soil CO2 in small sealed exetainers as a solid barium carbonate. Data obtained from established radiocarbon sampling procedures and this new novel approach were shown to be comparable and reproducible. This technique facilitated both sample collection and shipment as well as analysis by accelerator mass spectrometry (AMS), allowing for rapid, efficient sampling techniques to be deployed in remote areas. Results of this study show the carbonate method to be an economical and effective sampling method, and used at the Old Crow site, demonstrated that under current climate conditions, older organics in the subsurface do not confound the use of 14CO2 for source zone biodegradation assessment at this hydrocarbon impacted permafrost site.
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Vliv oxidu barnatého na tvorbu a vlastnosti portlandského slínku / The influence of barium oxide on the formation and properties of portland clinkerZezulová, Anežka January 2014 (has links)
Portland clinker is thanks to its large-scale production a continuously studied topic. Clinker, or Portland cement, is used for construction purposes, or for insulation and special applications. One of these special applications could be shielding of different types of radiation by making use of the content of barium ions. The present master’s thesis examines the influence of barium oxide on the formation and properties of Portland clinker, which could be, by incorporation of barium ions into the system, used as a binder for buildings resistant to various types of radiation. Barium sulfate and barium carbonate were added to the raw meal in order to prepare clinkers with different content of barium oxide. The effect of barium on the formation of clinker phases was studied (by XRD – Rietveld analysis and by the microscopic point integration), as well as the effects on the variations of temperature of the phase formation (TG-DTA) and the rate of alite formation under isothermal conditions. Furthermore, the ability of barium to become a part of clinker minerals was studied by SEM with EDS, and the solubility of barium phases by ICP-OES. The hydration of clinker minerals containing barium was studied by isothermal calorimetry.
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