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Visar resultat 1 - 5 av 24 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Geometry of numbers, class group statistics and free path lengths

    Författare :Samuel Holmin; Pär Kurlberg; Yiannis Petridis; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; geometry of numbers; lattices; class numbers; class groups; free path lengths; Mathematics; Matematik;

    Sammanfattning : This thesis contains four papers, where the first two are in the area of geometry of numbers, the third is about class group statistics and the fourth is about free path lengths. A general theme throughout the thesis is lattice points and convex bodies. LÄS MER

  3. 2. The role of the hydrological cycle in forest ecosystems : flow path, nutrient cycling and water-carbon interaction

    Författare :Yanzi Yan; MERGE: ModElling the Regional and Global Earth system; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; flow path; DOC concentration; groundwater; photosynthesis; Amazon rainforest; catchment geomorphology;

    Sammanfattning : Forest ecosystems, covering over a third of land on the Earth, play a significant role in the global hydrological cycle, and influence soil erosion and climate change. However, the distribution, movements, quality of water, and hydrological processes in forested ecosystems are not well understood yet. LÄS MER

  4. 3. Structural Uncertainties of Rock Fractures and their Effect on Flow and Tracer Transport

    Författare :Martin Stigsson; Vladimir Cvetkovic; Ki-Bok Min; KTH; []
    Nyckelord :Fracture; Flow; Transport; Orientation uncertainty; Roughness; Self-affine; Fractal; Shear; Aperture distribution.; Land and Water Resources Engineering; Mark- och vattenteknik;

    Sammanfattning : Att förstå flöde och transport av lösta ämnen genom sprickorna i berggrunden är viktigt för den långsiktiga säkerheten av ett geologiskt slutförvar av farligt avfall. I en diskret spricknätverksmodell byggs flödesvägarna upp av kedjor av flödesvägar genom de enskilda sprickorna i bergmassan. LÄS MER

  5. 4. On Directed Random Graphs and Greedy Walks on Point Processes

    Författare :Katja Gabrysch; Svante Janson; Takis Konstantopoulos; Thomas Mountford; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Directed random graphs; Tracy-Widom distribution; Poisson-weighted infinite tree; Greedy walk; Point processes;

    Sammanfattning : This thesis consists of an introduction and five papers, of which two contribute to the theory of directed random graphs and three to the theory of greedy walks on point processes.          We consider a directed random graph on a partially ordered vertex set, with an edge between any two comparable vertices present with probability p, independently of all other edges, and each edge is directed from the vertex with smaller label to the vertex with larger label. LÄS MER

  7. 5. Modeling framework for ageing of low alloy steel

    Författare :Magnus Boåsen; Pål Efsing; Jonas Faleskog; Carl F. O. Dahlberg; Christian Niordson; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Low alloy steel; length scale effects; size effects; plasticity; cleavage fracture; brittle fracture; weakest link; ageing; weld metal; Hållfasthetslära; Solid Mechanics;

    Sammanfattning : Ageing of low alloy steel in nuclear applications commonly takes the form as a hardening and an embrittlement of the material. This is due to the evolution of the microstructure during irradiation and at purely thermal conditions, as a combination or separate. LÄS MER