Sökning: "effective diffusion coefficient"

Visar resultat 1 - 5 av 26 avhandlingar innehållade orden effective diffusion coefficient.

1. 1. Modeling of Hindered Diffusion in Gels

   Författare :Jan Gutenwik; Avdelningen för kemiteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; effective diffusion coefficient; pore size distribution; obstruction; immobilization; modeling; adsorption kinetics; hindered diffusion; simulation program; proteins; Chemical technology and engineering; Kemiteknik och kemisk teknologi;

   Sammanfattning : Hindered diffusion occurs in the most different processes, as has been described in this thesis. It is very important to have an understanding of the influence of hindered diffusion on the mass transfer rate, especially when competing rate processes are acting simultaneously. LÄS MER

3. 2. Heterogeneous Materials - Diffusion, Laplace spectrum and NMR

   Författare :Matias Nordin; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; perturbation; nmr; diffusion; laplace operator; spectrum; heterogeneous materials;

   Sammanfattning : Relations to the effective diffusion constant and the relaxation rate of the time-dependent diffusion coefficient for porous systems are derived from the Laplace operator spectrum. The Padé approximation is then explained in terms of the Laplace operator spectrum. LÄS MER

4. 3. Diffusion of large molecules in steam-exploded wood

   Författare :Patric Kvist; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Wood; Large Molecules; Diffusion; LBM; Steam Explosion; FRAP;

   Sammanfattning : The diffusion of large molecules in wood pre-treated with steam explosion is important to understand in the context of the materials biorefinery. Steam explosion is a pretreatment method used to both open up the internal structure of wood and increase the accessibility of the cell walls of the wood with the use of high-pressure steam, and it is considered an energy-efficient method. LÄS MER

5. 4. Heterogeneous Materials - Diffusion, Laplace Spectrum, and Nuclear Magnetic Resonance

   Författare :Matias Nordin; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; eigenfunctions; eigenvalues; propagator; diffusion; Laplace operator; Nuclear Magnetic Resonance;

   Sammanfattning : In this thesis diffusion in heterogeneous materials is studied using spectral analysisof the Laplace operator. Relations to the effective diffusion constant and therelaxation rate of the time-dependent diffusion coefficient for porous systems arederived from the Laplace operator’s spectrum. LÄS MER

7. 5. On the Growth of Bone through Stress Driven Diffusion and Bone Generation Processes

   Författare :Gustav Lindberg; Hållfasthetslära; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; bone growth; Osteogenesis; Diffusion in bone; stress enhanced diffusion; Ginzburg-Landau; phase-field; diffusion experiment; Conductivity; Kalman filter; finite element method; Fourier series; Fick’s law; Osteology;

   Sammanfattning : In order to prevent or modify bone degeneration due to rest or due to diseases such as osteopenia and osteoporosis, the modeling and remodeling of bone tissue must be better understood. In this thesis it is assumed that the primary condition leading to bone growth is a change of the chemical environment caused by transport of matter resulting from stress driven diffusion. LÄS MER