Christoph Lohmann – författare

Radical Passion examines eighty essays and reports on the United States (1852-1865) by the German-American journalist Ottilie Assing (1819-1884) along with twenty-seven extant letters from Assing to Frederick Douglass during the years 1870-1879. A keen and critical observer of the American scene before and during the Civil War, Assing was passionately committed to her personal freedom and to political and social equality for African Americans. She believed in radical social movements, backed the German Revolution of 1848, and became an enthusiastic supporter of radical abolitionism, women's emancipation, and civil rights for black Americans. For almost three decades, she and Frederick Douglass were close intellectual collaborators and lovers. The reports and essays, originally written in German, are presented in their first English translation; an introduction provides biographical background and historical context.

ChristophLohmann beschäftigt sich mit numerischen Verfahren für die Fokker-Planck-Gleichung.Ausgehend von einer Fourierapproximation leitet er notwendige Bedingungen fürdie Nichtnegativität der Wahrscheinlichkeitsdichte und positive Semidefinitheitzugehöriger Orientierungstensoren her. Unter Verwendung dieser Bedingungen entwickeltder Autor neuartige Korrekturtechniken für die Fourierkoeffizienten, die zueiner genauen und physikkonformen Approximation der Orientierungstensorenführen.

Christoph Lohmann introduces a very general framework for the analysis and design of bound-preserving finite element methods. The results of his in-depth theoretical investigations lead to promising new extensions and modifications of existing algebraic flux correction schemes. The main focus is on new limiting techniques designed to control the range of solution values for advected scalar quantities or the eigenvalue range of symmetric tensors. The author performs a detailed case study for the Folgar-Tucker model of fiber orientation dynamics. Using eigenvalue range preserving limiters and admissible closure approximations, he develops a physics-compatible numerical algorithm for this model.