0000000000681773
AUTHOR
Stefan Kurz
Functional a posteriori error estimates for boundary element methods
Functional error estimates are well-established tools for a posteriori error estimation and related adaptive mesh-refinement for the finite element method (FEM). The present work proposes a first functional error estimate for the boundary element method (BEM). One key feature is that the derived error estimates are independent of the BEM discretization and provide guaranteed lower and upper bounds for the unknown error. In particular, our analysis covers Galerkin BEM and the collocation method, what makes the approach of particular interest for scientific computations and engineering applications. Numerical experiments for the Laplace problem confirm the theoretical results.
Dextran-sulfate-adsorption of atherosclerotic lipoproteins from whole blood or separated plasma for lipid-apheresis--comparison of performance characteristics with DALI and Lipidfiltration.
For many years dextran sulfate adsorption (DSA) treatment of separated plasma has been an established technology for low-density lipoprotein (LDL)-elimination. Recently a system for the treatment of whole blood based on DSA was introduced into clinical practice. To further characterize DSA treatment of whole blood, the performance characteristics of both DSA modalities were compared at two investigational sites with two alternative LDL apheresis systems being already in routine clinical use. In prospective cross-over design, DSA whole blood treatment was compared with a whole blood polyacrylate LDL adsorption system (DALI) in one study group. DSA for plasma treatment was compared with Lipid…
BEM-Based Magnetic Field Reconstruction by Ensemble Kálmán Filtering
Abstract Magnetic fields generated by normal or superconducting electromagnets are used to guide and focus particle beams in storage rings, synchrotron light sources, mass spectrometers, and beamlines for radiotherapy. The accurate determination of the magnetic field by measurement is critical for the prediction of the particle beam trajectory and hence the design of the accelerator complex. In this context, state-of-the-art numerical field computation makes use of boundary-element methods (BEM) to express the magnetic field. This enables the accurate computation of higher-order partial derivatives and local expansions of magnetic potentials used in efficient numerical codes for particle tr…
Formulierung der Elektrodynamik mit Differentialformen
In diesem Kapitel werden die Maxwell’schen Gleichungen mit Hilfe von Differentialformen ausgedruckt. Dabei werden die Operatoren Gradient, Rotation und Divergenz durch einen einzigen Operator der auseren Ableitung ersetzt. Ebenso werden die Integralsatze von Gaus und Stokes durch einen einzigen Integralsatz ersetzt. Ferner wird klar, dass die Maxwell’schen Gleichungen topologische Gleichungen sind, die sich in der Formulierung mit Differentialformen unter Beibehaltung ihrer Form in beliebige Koordinatensysteme transformieren lassen. Die metrische Information steckt in den Materialbeziehungen und kann mit Hilfe sogenannter Hodge-Operatoren ausgedruckt werden. Neben der damit einhergehenden u…