Sökning: "transport and reaction rates"

Visar resultat 1 - 5 av 41 avhandlingar innehållade orden transport and reaction rates.

1. 1. Long-term development, modeling and management of nutrient loading to inland and coastal waters

   Författare :Amelie Darracq; Georgia Destouni; Andrea Rinaldo; Stockholms universitet; []
   Nyckelord :Nutrients; catchments; environmental management; climate change; population and lifestyle development; subsurface-surface water interactions; long-term simulations; nutrient retention; modeling; hydrology; transport processes; biogeochemistry; scaling; transport and reaction rates; Physical Geography; geografi med naturgeografisk inriktning;

   Sammanfattning : Environmental and water system protection and restoration require accurate knowledge and quantification of waterborne pollutant transport, retention-release and transformation processes taking place in the subsurface, river, lake and sea water systems, and at the interfaces between these systems. This thesis investigates the importance of spatial model resolution for such quantification and the possible long-term nutrient load development under different human perturbations and nutrient source management scenarios in the Swedish Norrström drainage basin, based on simulations with the GIS-based dynamic nutrient transport-attenuation model POLFLOW. LÄS MER

3. 2. Modified oxygen and hydrogen transport in Zr-based oxides

   Författare :Clara Anghel; Gunnar Hultquist; Magnus Limbäck; Truls Norby; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Zirconia; Zirconium; Zircaloy; hydrogen and oxygen diffusion; SPP; oxygen dissociating elements; oxidation; dissociation; hydration; CO adsorption; molecular transport; porosity.; Materials science; Teknisk materialvetenskap;

   Sammanfattning : Most metals and alloys in the presence of oxygen and moisture will instantaneously react and form a thin (2-5 nm) surface oxide layer. For further reaction to occur, oxygen ions and/or metal cations often diffuse through the already formed oxide layer. LÄS MER

4. 3. Homogenization of pseudoparabolic reaction-diffusion-mechanics systems : Multiscale modeling, well-posedness and convergence rates

   Författare :Arthur J. Vromans; Adrian Muntean; Claudia Timofte; Karlstads universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Reaction-diffusion-mechanics system; parameter delimitation; parabolic-pseudoparabolic equations; weak solvability; Rothe method; periodic homogenization; corrector estimates; vanishing thin domains; Matematik; Mathematics;

   Sammanfattning : In this dissertation, parabolic-pseudoparabolic equations are proposed to couple chemical reactions, diffusion, flow and mechanics in heterogeneous materials using the framework of mixture theory. The weak solvability is obtained in a one dimensional setting for the full system posed in a homogeneous domain - a formulation which we have obtained using the classical mixture theory. LÄS MER

5. 4. Automatic Analysis and Reduction of Reaction Mechanisms for Complex Fuel Combustion

   Författare :Daniel Nilsson; Förbränningsfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; hydraulik; Complex fuel combustion; Reduced kinetic models; skeletal mechanism; QSSA; hydraulics; Mechanical engineering; vacuum technology; Maskinteknik; vibration and acoustic engineering; vakuumteknik; vibrationer; akustik; Physics; Fysik; Chemistry; Kemi; Fysicumarkivet A:2001:Nilsson;

   Sammanfattning : This work concentrates on automatic procedures for simplifying chemical models for realistic fuels using skeletal mechanism construction and Quasi Steady-State Approximation (QSSA) applied to detailed reaction mechanisms. To automate the selection of species for removal or approximation, different indices for species ranking have thus been proposed. LÄS MER

7. 5. Chemical transport and reaction rates during fluid-rock interaction

   Författare :Fredrik Arghe; Stockholms universitet; []
   Nyckelord :;

   Sammanfattning : .... LÄS MER