ubc Anomalous diffusion and random walks on random fractals 2010-03-08 [Electronic ed.] prv Universitätsbibliothek Chemnitz Universitätsbibliothek Chemnitz, Chemnitz Fakultät für Naturwissenschaften male Hanoi, Vietnam male male male male male The purpose of this research is to investigate properties of diffusion processes in porous media. Porous media are modelled by random Sierpinski carpets, each carpet is constructed by mixing two different generators with the same linear size. Diffusion on porous media is studied by performing random walks on random Sierpinski carpets and is characterized by the random walk dimension $d_w$. In the first part of this work we study $d_w$ as a function of the ratio of constituents in a mixture. The simulation results show that the resulting $d_w$ can be the same as, higher or lower than $d_w$ of carpets made by a single constituent generator. In the second part, we discuss the influence of static external fields on the behavior of diffusion. The biased random walk is used to model these phenomena and we report on many simulations with different field strengths and field directions. The results show that one structural feature of Sierpinski carpets called traps can have a strong influence on the observed diffusion properties. In the third part, we investigate the effect of diffusion under the influence of external fields which change direction back and forth after a certain duration. The results show a strong dependence on the period of oscillation, the field strength and structural properties of the carpet. 500 Fraktal Stochastischer Prozess Anomalous diffusion Complex Monte Carlo Methods urn:nbn:de:bsz:ch1-201000205 Technische Universität Chemnitz dgg Technische Universität Chemnitz, Chemnitz Do Hoang Ngoc Anh 1979-08-16 aut Karl Heinz Hoffmann Prof. Dr. dgs rev Guenter Radons Prof. Dr. dgs rev eng 2010-02-05 2010-02-05 born digital qucosa:19268Anomalous diffusion and random walks on random fractals doctoral_thesis