Search for dissertations about: "Branching diffusion"

Showing result 1 - 5 of 16 swedish dissertations containing the words Branching diffusion.

  2. 1. Small Molecule Diffusion in Spherulitic Polyethylene : Experimental Results and Simulations

    Author : Alessandro Mattozzi; Ulf W. Gedde; Alan H. Windle; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; diffusion; polyethylene; poly ethylene-co-octene ; free volume; morphology; intermediate phase; spherulite; Monte Carlo simulation; Polymer chemistry; Polymerkemi;

    Abstract : The diffusion of small-molecule penetrants in polyethylene is hindered by impenetrable crystals and by the segmental constraints imposed by the crystals on the penetrable phase. Liquid and vapour n-hexane sorption/desorption measurements were performed on metallocene catalyzed homogenous poly(ethylene-co-octene)s. READ MORE

  4. 2. Multi-trait Branching Models with Applications to Species Evolution

    Author : Daniah Tahir; Ingemar Kaj; Martin Lascoux; Asger Hobolth; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Markov models; branching processes; density dependence; discrete traits; species trees; diversification rates; diffusion approximation;

    Abstract : This thesis provides an analysis of the evolution of discrete traits and their effect on the birth and survival of species using the theory of supercritical, continuous time Markov branching processes. We present a branching modeling framework that incorporates multi-trait diversification processes associated with the emergence of new species, death of existing species, and transition of species carrying one type of a trait to another. READ MORE

  5. 3. Stochastic Models in Phylogenetic Comparative Methods: Analytical Properties and Parameter Estimation

    Author : Krzysztof Bartoszek; Göteborgs universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Adaptation; Adaptation; Birth-death process; Branching diffusion; Brownian motions; Conditioned branching process; Evolution; General Linear Model; Hybridization; Macroevolution; Measurement error; Multivariate phylogenetic comparative method; Optimality; Ornstein-Uhlenbeck process; Phyletic gradualism; Phylogenetic inertia; Phylogenetic uncertainty; Punctuated equilibrium; Yule tree; Macroevolution;

    Abstract : Phylogenetic comparative methods are well established tools for using inter-species variation to analyse phenotypic evolution and adaptation. They are generally hampered, however, by predominantly univariate approaches and failure to include uncertainty and measurement error in the phylogeny as well as the measured traits. READ MORE

  6. 4. Diffusion approximation and extinction of almost critical general branching processes

    Author : Torbjörn Jönsson; Göteborgs universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : .... READ MORE

  7. 5. Computational framework for studying charge transport in high-voltage gas-insulated systems

    Author : Shailendra Singh; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; barrier discharge; low temperature plasma; drift diffusion equation; gaseous dielectrics; gas discharge; streamer propagation; high voltage;

    Abstract : Electrical switchgear industry dealing with transmission and distribution of power is strongly affected by the changing dynamics of climate control. Their main contribution to the global warming is through SF6 gas, having a GWP of 23500 (times of CO2). SF6 plays an important role in providing electrical insulation for these high voltage systems. READ MORE