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Visar resultat 1 - 5 av 9 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Experimental and Modelling Studies on the Spreading of Non-Aqueous Phase Liquids in Heterogeneous Media

   Författare :Fritjof Fagerlund; Auli Niemi; Tissa Illangasekare; Karsten Jensen; Uppsala universitet; []
   Nyckelord :Hydrology; NAPL; Multi-phase flow; Modelling; Experiment design; Heterogeneity; Constitutive relations; Multi-constituent contaminants; Capillary pressure; Relative permeability; Hysteresis; Hydrologi;

   Sammanfattning : Non-Aqueous Phase Liquids (NAPLs) include commonly occurring organic contaminants such as gasoline, diesel fuel and chlorinated solvents. When released to subsurface environments their spreading is a complex process of multi-component, multi-phase flow. LÄS MER

3. 2. Numerical Methods for Darcy Flow Problems with Rough and Uncertain Data

   Författare :Fredrik Hellman; Axel Målqvist; Auli Niemi; Fritjof Fagerlund; Robert Scheichl; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; numerical homogenization; multiscale methods; rough coefficients; high contrast coefficients; mixed finite elements; cdf estimation; multilevel Monte Carlo methods; Darcy flow problems; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

   Sammanfattning : We address two computational challenges for numerical simulations of Darcy flow problems: rough and uncertain data. The rapidly varying and possibly high contrast permeability coefficient for the pressure equation in Darcy flow problems generally leads to irregular solutions, which in turn make standard solution techniques perform poorly. LÄS MER

4. 3. Virus Fate and Transport in Groundwater : Organic matter, uncertainty, and cold climate

   Författare :Jean-Marc Mayotte; Keven Bishop; Stephan Köhler; Fritjof Fagerlund; Sven Halldin; Constantinos V. Chrysikopoulos; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; managed aquifer recharge; organic matter; virus; numerical modeling; uncertainty; Hydrology; Hydrologi; Mikrobiologi; Microbiology;

   Sammanfattning : Water managers must balance the need for clean and safe drinking water with ever-increasing amounts of waste-water. A technique for treating and storing surface water called “managed aquifer recharge” (MAR) is frequently used to help maintain this balance. LÄS MER

5. 4. Remediation of per- and polyfluoroalkyl substance-contaminated soil and groundwater, using electrokinetic and stabilisation methods

   Författare :Georgios Niarchos; Fritjof Fagerlund; Anett Georgi; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; PFAS; contamination; emerging contaminants; forever chemicals; pollution; soil; groundwater; remediation; electrokinetic; stabilisation; activated carbon;

   Sammanfattning : Per- and polyfluoroalkyl substances, commonly known as PFAS, are emerging contaminants with a worldwide environmental distribution and a concerning (eco)toxicological profile. The omnipresence of PFAS in various environmental media poses risks to the quality of our drinking water sources. LÄS MER

7. 5. Biogeochemical Processes in Denitrifying Woodchip Bioreactors and their Application in the Mining Industry

   Författare :Albin Nordström; Roger Herbert; Fritjof Fagerlund; Gunno Renman; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; water treatment; mine drainage; nitrate; nitrous oxide; DNRA; fermentation; syntrophy; temperature; kväverening; gruvvatten; nitrat; lustgas; DNRA; fermentation; syntrofi; temperatur; Hydrology; Hydrologi;

   Sammanfattning : This thesis evaluates passive denitrifying woodchip bioreactors (DWBs) for the removal of nitrate (NO3-) in neutral pH mine drainage, where water is passed through a carbon-rich porous matrix (e.g. woodchips) for the reduction of NO3- to nitrogen gas. LÄS MER