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Visar resultat 1 - 5 av 43 avhandlingar som matchar ovanstående sökkriterier.

1. 1. On finite element schemes for Vlasov-Maxwell system and Schrödinger equation

   Författare :Christoffer Standar; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Nonlinear Schrödinger equation; Nitsche scheme; Streamline diffusion; Vlasov-Maxwell; a posteriori error analysis; a priori error analysis; hp-scheme; a posteriori error analysis;

   Sammanfattning : This thesis treats finite element schemes for two kind of problems, the Valsov-Maxwellsystem and the nonlinear Schrödinger equation. We study streamline diffusion schemes applied for numerical solution of the one and one-half dimensional relativistic Vlasov-Maxwell system. The study is made both in a priori and a posteriori settings. LÄS MER

3. 2. A moving boundary problem for capturing the penetration of diffusant concentration into rubbers : Modeling, simulation and analysis

   Författare :Surendra Nepal; Adrian Muntean; Yosief Wondmagegne; Magnus Ögren; Karlstads universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Moving boundary problem; finite element method; a priori error estimate; a posteriori error estimate; order of convergence; diffusion of chemicals into rubber; swelling; Matematik; Mathematics;

   Sammanfattning : We propose a moving-boundary scenario to model the penetration of diffusants into rubbers. Immobilizing the moving boundary by using the well-known Landau transformation transforms the original governing equations into new equations posed in a fixed domain. LÄS MER

4. 3. Mathematical analysis and approximation of a multiscale elliptic-parabolic system

   Författare :Omar Richardson; Adrian Muntean; Alfred Schmidt; Karlstads universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Two-scale modelling; two-scale Galerkin approximation; inverse Robin estimates; elliptic-parabolic system; a priori analysis; a posteriori error estimators; Matematik; Mathematics;

   Sammanfattning : We study a two-scale coupled system consisting of a macroscopic elliptic equation and a microscopic parabolic equation. This system models the interplay between a gas and liquid close to equilibrium within a porous medium with distributed microstructures. We use formal homogenization arguments to derive the target system. LÄS MER

5. 4. Models for capturing the penetration of a diffusant concentration into rubber : Numerical analysis and simulation

   Författare :Surendra Nepal; Adrian Muntean; Nadja Ray; Karlstads universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; transport of diffusants; moving-boundary problem; finite element method; a priori and a posteriori error estimates; random walk method; two-scale coupled system; Matematik; Mathematics;

   Sammanfattning : Understanding the transport of diffusants into rubber plays an important role in forecasting the material's durability. In this regard, we study different models, conduct numerical analysis, and present simulation results that predict the evolution of the penetration front of diffusants. LÄS MER

7. 5. Parameter identification in constitutive models with a posteriori error control and sensitivity assessment

   Författare :Håkan Johansson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Sensitivity analysis; Goal-oriented error estimate; Calibration; Parameter identification;

   Sammanfattning : In this thesis a framework for the calibration of constitutive models is presented. The framework involves theformulation of an optimization problem which is solved usingstrategies based on, essentially, Newton's method. LÄS MER