Sökning: "length scale effects"

Visar resultat 16 - 20 av 143 avhandlingar innehållade orden length scale effects.

  1. 16. Upscaling of Flow, Transport, and Stress-effects in Fractured Rock

    Författare :Johan Öhman; Auli Niemi; Ove Stephansson; Robert W Zimmerman; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Hydrology; Upscaling; fractured media; flow; solute transport; thermo-hydro-mechanical processes; hybrid approach; continuum approximation; discrete fracture network; stochastic continuum; Hydrologi; Hydrology; Hydrologi;

    Sammanfattning : One of many applications of geohydraulic modelling is assessing the suitability of a site to host a nuclear waste repository. This modelling task is complicated by scale-dependent heterogeneity and coupled thermo-hydro-mechanical (THM) processes. LÄS MER

  3. 17. Lean NOx reduction over silver-alumina from lab-scale to real conditions - Effects of reducing agent and catalyst composition

    Författare :Fredrik Gunnarsson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; ethanol; Ag Al2O3; Pt-doping; Lean NOx reduction; HC-SCR; low-temperature activity; catalyst ageing; biofuels;

    Sammanfattning : Lean NOx reduction over silver-alumina from lab-scale to real conditions Effects of reducing agent and catalyst compositionFREDRIK GUNNARSSONApplied surface chemistryDepartment of Chemical and Biological EngineeringChalmers University of TechnologyAbstractThe focus of this work is to increase the understanding of lean NOx reduction over silver-alumina catalysts using hydrocarbons as the reducing agent (HC-SCR), in particular by investigating the effect of silver loading, the role of platinum doping, and the effect of the type of reducing agent. In addition, the effects of aging and hydrothermal treatment on the catalytic activity and selectivity, and the influence of real engine exhausts were investigated, with special attention to the low-temperature activity. LÄS MER

  4. 18. Quantum mechanical effects on charge transport in two mesoscopic systems

    Författare :Gustav Sonne; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Nanoelectromechanical systems; NEMS; carbon nanotubes; carbon peapods; excess current; superconducting weak links; suspended carbon nanotubes; non-linear resonances;

    Sammanfattning : Carbon nanotubes are one of the most promising building blocks for the developing field of nanoelectromechanics. Due to their unique electronic and mechanical properties, these all-carbon systems have been suggested for a range of applications where one wishes to utilse the coupling between mechanical and electronic degrees of freedom on the nanometer length scale. LÄS MER

  5. 19. Natural enemies: Functional aspects of local management in agricultural landscapes

    Författare :Helena Hanson; Biodiversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Agricultural intensification; sustainable agriculture; land use; management intensity; landscape scale; ecosystem services; biological control; species trait; pesticides; predatory arthropods; parasitoids; pollen beetles;

    Sammanfattning : Agricultural intensification has raised the global food production but also caused major concerns about environmental and health effects, including contamination by pesticides. Pesticide applications may induce toxicity not only on the target pest species but especially on non-target species. LÄS MER

  7. 20. Effects of boundary conditions and unsteadiness on draft tube flow

    Författare :Michel Cervantes; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Strömningslära; Fluid Mechanics;

    Sammanfattning : The present research focuses on flow properties of the elbow draft tube. This element has a major function in low head turbines, since up to half of the losses may arise there at part load. The use of computational fluid dynamic (CFD) to redisign a draft tube necessitates detailed knowledged of the boundary conditions. LÄS MER