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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Investigating the Electrochemical Interaction of Microorganisms with MetalSurfaces During Microbiologically Influenced Corrosion

Sadek, Anwar 11 August 2022 (has links)
No description available.
22

Development of Photochemically Initiated Direct and Indirect Luminescence Detection Methods for Liquid Chromatography (LC) and Study of Aromatic Sulfonates and Phospholipids Using Reversed Phase Ion-Pair LC-Mass Spectrometry

Zhang, Wei 13 November 2003 (has links)
No description available.
23

Focused flow during water infiltration into ethanol-contaminated unsaturated porous media

Jazwiec, Alicja N. 06 1900 (has links)
The increasing commercial and industrial use of ethanol, i.e., in biofuel and gasoline, has generated increased incidents of vadose zone contamination by way of ethanol spills and releases. This has increased the interest in better understanding infiltration behaviours of ethanol in unsaturated porous media and the multiphase interactions in the vadose zone. Solute-dependent capillarity-induced focused flow (SCIFF) is a vertical, highly focused flow infiltration behaviour first reported by Smith et al. (2011) in butanol-contaminated sands. Through the use of highly controlled laboratory experiments, this thesis research investigates focused flow (SCIFF) and related behaviours through water infiltration into ethanol-contaminated unsaturated sand. Focused flow behaviours (SCIFF) were demonstrated through the infiltration of water into an ethanol-contaminated unsaturated sand using both constant flux and constant head methodologies. The observation of focused flow behaviours in ethanol-contaminated sand supported the primary hypothesis of this work. The secondary hypothesis was also supported, as focused flow behaviours were not observed, rather stable semicircular infiltration patterns were observed during ethanol infiltration into water-wet sand. Comparisons between constant flux and constant head application methods under similar flow rates and fluid volumes produced similar results. The zone of lower saturation, or the “halo effect” reported in previous literature, was strongly expressed during water infiltration in ethanol-contaminated sand. This halo effect is affected by the maximum (at 40% to 50%) of aqueous concentration of ethanol. This maximum enhances the zone of lower saturation and stabilizes the solute front. The SCIFF focused flow also overcame the effects of minor heterogeneities in the sand. However, additional laboratory and modelling work is required to further understand the extent of SCIFF behaviour. / Thesis / Master of Science (MSc) / Understanding the behaviour and interaction of water and contaminants in soils is important as environmental contamination and spills can have devastating environmental impacts. In recent decades, ethanol spills and accidental releases onto ground surface have increased as the commercial and industrial use of ethanol has increased. The goals of this work were to qualitatively visualize and quantify the unique nature of water infiltration into the ethanol-contaminated soil and understand the complex mechanisms behind water-ethanol interactions. This research showed that water infiltration creates an uncommon vertical, focused pattern when flowing into sand contaminated by ethanol. However, when ethanol is applied to standard water-wet sand, that behaviour is not observed. This work provided greater insight into the nature of ethanol-contaminated soils. These findings furthered the understanding needed to evaluate impacts that ethanol contamination can have on remedial efforts and the rate of migration of contaminants to groundwater.
24

Teststation för industriella UV-celler / Test station for industrial UV-cells

Ahmed, Masud Omar January 2019 (has links)
GE Healthcare Bio-Sciences AB in Umeå produce a variety of chromatography systems. One of the main components in chromatography is the UV module, which measure the light absorption of different wavelengths in the liquid being pumped through a cell. Currently at the Umeå site two types of UV-cells are produced; lab cells and industrial cells. The current test station for the industrial UV-cells is outdated, in disrepair and no longer supported.  GE has developed a test station for the lab cells that evaluates UV and flow properties, the data is stored in GE’s own production database, Prodas. The aim of this work is to design a test station for industrial UV-cells to improve the quality of the cells. The primary goal is a test station that can measure pressure, flow and absorption. The secondary goal is to discover and if possible, implement solutions that will streamline and automate the test station. A prototype of a test station for industrial UV-cells based on that for lab cells has been developed. The solution consists of an adapter that links the light path from the monitor through the UV-cell to the detector. The test station can measure pressure, flow and absorption but can only perform absorption and leakage tests.  Automation and efficiency have been accomplished in the form of scripts used to conduct absorption and leakage tests. The test station requires further development before it can be used in the production line. / GE Healthcare Bio-Sciences AB i Umeå tillverkar ett flertal system, ett av systemen är vätskekromatografen. Vätskekromatografen är en kemisk separationsmetod som använder sig av en UV-monitor, UV-detektor och en UV-cell för att mäta absorptionen av en lösning och framta koncentrationen av det eftersökta ämnet. På anläggningen i Umeå tillverkas två typer av UV-celler; laborationceller och industriceller. För labbcellerna har GE utvecklat en teststation som testar och utvärderar UV och flödesegenskaper samt lagrar data i GE:s egen produktionsdatabas, Prodas. Den befintliga stationen för industriceller är äldre och omodern, en utveckling behövs för att upprätthålla högre kvalité. Syftet med detta projekt är att uppdatera teststationen för industriella UV-celler till samma nivå som stationen för laborationsceller. Det primära målet är att konstruera och designa en teststation för industriella UV-celler som kan mäta tryck, flöde och absorption. Det sekundära målet är att upptäcka och om möjligt verkställa lösningar som kommer effektivisera och automatisera mätningarna. En prototyp av en teststation för industriella UV-celler baserat på den för laborationceller har framtagits, och består av en adapterlösning som används för att sammanlänka ljusbanan från monitorn genom flödescellen till detektorn. Prototypen kan enbart utföra absorption och läckagemätningar. Automatisering och effektivisering har utförts i form av scripts som används för att genomföra absorptions och läckagemätning. Teststationen kräver fortsatt vidareutveckling innan den kan används i produktionslinjen.

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