Search for dissertations about: "natural formation"

Showing result 1 - 5 of 2242 swedish dissertations containing the words natural formation.

  1. 1. Polybrominated dibenzo-p-dioxins : Natural formation mechanisms and biota retention, maternal transfer, and effects

    Author : Kristina Arnoldsson; Peter Haglund; Patrik Andersson; Walter Vetter; Umeå universitet; []
    Keywords : NATURAL SCIENCES; NATURVETENSKAP; polybrominated dibenzo-p-dioxins; PBDDs; Baltic Sea; uptake; retention; maternal transfer; metabolism; bioavailability; natural formation; precursor; bromoperoxidase; bromophenol; photochemical transformation; oxidative coupling; hydroxylated polybrominated diphenyl ethers; Chemistry; Kemi; analytisk kemi; Analytical Chemistry;

    Abstract : Polybrominated dibenzo-p-dioxins (PBDD) and dibenzofurans (PBDF) are a group of compounds of emerging interest as potential environmental stressors. Their structures as well as toxic responses are similar to the highly characterized toxicants polychlorinated dibenzo-p-dioxins. READ MORE

  2. 2. Fuel conversion and ash formation interactions : a thermochemical study on lignocellulosic biomass

    Author : Anna Strandberg; Markus Broström; Rainer Backman; Christoffer Boman; Maria Zevenhoven; Umeå universitet; []
    Keywords : ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; NATURAL SCIENCES; ENGINEERING AND TECHNOLOGY; ENGINEERING AND TECHNOLOGY; Char conversion; pyrolysis; devolatilization; ash transformation; biomass; fuel characterization; fuel composition; ash composition; silicate formation; carbonate formation; thermogravimetric analysis; micro-tomography;

    Abstract : Biomass is considered to be CO2 neutral, and to be able to reduce the dependency on fossil fuels the need for expanded and sustainable biomass feedstock is increasing. Ash-related problems are some of the most important aspects of this increasing use of new biomass assortments in thermal energy conversion systems. READ MORE

  3. 3. Dissipative formation of galaxies in hierarchical cosmology

    Author : John Hultman; Uppsala universitet; []
    Keywords : NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Astronomy; merical methods; hydrodynamics; galaxies: formation; galaxies: elliptical; galaxies: structure; star formation; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik; Theoretical Astrophysics; teoretisk astrofysik;

    Abstract : A description and detailed tests of a numerical code for simulations of galaxy formation is presented. The dynamics is followed with fully adaptive and Lagrangian Smooth Particle Hydrodynamics (SPH) combined with a gravitational tree method. The severe numerical problem of sub-resolution clustering is solved by merging of gas particles. READ MORE

  4. 4. Formation of Block Copolymer and Surfactant Vesicles

    Author : Karin Bryskhe; Fysikalisk kemi; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Polymerteknik; Fysikalisk kemi; biopolymers; Polymer technology; nanoparticles; Lipid; triblock copolymer; surfactants; Nonionic; Vesicles; Formation; Physical chemistry;

    Abstract : In this thesis temperature induced vesicle formation in both a block copolymer system and nonionic surfactant system have been investigated. The block copolymer is a triblock copolymer of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO), PEO-PPO-PEO, with the average molecular composition of EO5PO68EO5 and the commercial trade name Pluronic L121 (papers I, II). READ MORE

  5. 5. The Dynamics of Star Cluster Formation

    Author : Juan Pablo Farias Osses; Chalmers University of Technology; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Astronomy Astrophysics; Star Formation; Star Cluster Formation; N-body simulations;

    Abstract : How do star clusters form? We care, since these are the birth sites of most stars, perhaps including our own Sun. There are a great variety of different theoretical models of cluster formation and our main goal in this thesis is to examine the implications of these for the dynamical evolution of a cluster's stellar population, including the ejected stars. READ MORE