A dynamical core for topological directed graphs

A topological graph, or quiver, is a directed graph where the edge and vertex spaces are topological spaces. The C*-algebra associated with the graph is a Cuntz-Pimsner algebra of an associated C*-correspondence over an abelian C*-algebra. For a given graph satisfying a properness hypothesis we construct and abstractly characterize a subgraph containing the iterative dynamical core of the original graph. The C*-algebra of this subgraph is a quotient of the C*-algebra of the graph, and under some additional assumptions is a crossed product C*-algebra by a shift endomorphism. This is accomplished using a composition product of topological graphs

Compact κ\kappa-deformation and spectral triples

We construct discrete versions of $\kappa$-Minkowski space related to a certain compactness of the time coordinate. We show that these models fit into the framework of noncommutative geometry in the sense of spectral triples. The dynamical system of the underlying discrete groups (which include some Baumslag--Solitar groups) is heavily used in order to construct \emph{finitely summable} spectral triples. This allows to bypass an obstruction to finite-summability appearing when using the common regular representation. The dimension of these spectral triples is unrelated to the number of coordinates defining the $\kappa$-deformed Minkowski spaces.Comment: 30 page

Advances in modeling transport phenomena in material-extrusion additivemanufacturing: Coupling momentum, heat, and mass transfer

Material-extrusion (MatEx) additive manufacturing involves layer-by-layer assembly ofextruded material onto a printer bed and has found applications in rapid prototyping.Both material and machining limitations lead to poor mechanical properties of printedparts. Such problems may be addressed via an improved understanding of thecomplex transport processes and multiphysics associated with the MatEx process.Thereby, this review paper describes the current (last 5 years) state of the art modelingapproaches based on momentum, heat and mass transfer that are employed in aneffort to achieve this understanding. We describe how specific details regardingpolymer chain orientation, viscoelastic behavior and crystallization are often neglectedand demonstrate that there is a key need to couple the transport phenomena. Such acombined modeling approach can expand MatEx applicability to broader applicationspace, thus we present prospective avenues to provide more comprehensive modelingand therefore new insights into enhancing MatEx performanc

Hecke Algebras and Semigroup Crossed Product C*-Algebras

For an almost normal subgroup Gamma0 of a discrete group Gamma, conditions are given which allow one to define..

Schlagwettergeschuetzte Fernseheinrichtung zur Aufnahme der Floeze und ihres Nebengesteins sowie tektonischer Flaechen in Bohrloechern unter Tage Schlussbericht

With 27 figs., 7 tabs., 12 refs.SIGLECopy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman