A Kinetic Model for Grain Growth

We provide a well-posedness analysis of a kinetic model for grain growth introduced by Fradkov which is based on the von Neumann-Mullins law. The model consists of an infinite number of transport equations with a tri-diagonal coupling modelling topological changes in the grain configuration. Self-consistency of this kinetic model is achieved by introducing a coupling weight which leads to a nonlinear and nonlocal system of equations. We prove existence of solutions by approximation with finite dimensional systems. Key ingredients in passing to the limit are suitable super-solutions, a bound from below on the total mass, and a tightness estimate which ensures that no mass is transported to infinity in finite time.Comment: 24 page

A comparative approach to technology adoption: Explaining inter-technology variation in behavioral intention to adopt

This article takes a fresh approach to technology adoption, using a detailed comparison between adoption decision-making on a variety of eID technologies to illuminate the theoretical question of how technology’s characteristics influence the antecedent factors of behavioural intention to use. Selecting four characteristics whose relevance is suggested but not really tested by the existing literature, namely the hedonic or utilitarian ways the technology is used, the familiarity of the technology for the user, the level of state intervention in the implementation or regulation of the technology use and the potential privacy intrusion the technology represents, we investigate whether diversity in these characteristics accounts for variation in the technology-adoption model. The model developed and used in this research is an integration of selected elements from TAM and DOI which enables a precise analysis of the technology adoption process. Using hypothesized scenarios in a survey among 3,947 people from 4 EU27 countries, this study provides empirical evidence –through SEM-PLS analysis- of individual decision-making processes, demonstrating that the variables measured in TAM-based models should be taken into account along with the characteristics of the individual technology considered

A Perfect Couple

Henseler, J., Schmidt, H. J., & Redler, J. J. (2023). Design Science and Marketing: A Perfect Couple. Journal of Creating Value. https://doi.org/10.1177/23949643231200703This special issue of the Journal on Creating Value about ‘Creating Value through Design Science’ and the articles therein aim at showcasing how design science research in the field of creating value can look like.publishersversionepub_ahead_of_prin

DYNAMIC DISPERSION MODELLING OF ODOURS AND AEROSOLS

The transmission of dust particles is one of the interesting processes in the dispersion of aerosols. Due to the fact that it is impossible to follow the track of every single particle, a lot of effects and their parameters must be known to simulate the dispersion. At the Harmo 7 conference a dynamic model to simulate the dispersion of odours was presented, before. This model is based on a numerical solution of the Navier-Strokes equation. Building upon this effort the dispersion model was enhanced, so that it is now possible to simulate the dispersion of aerosol particles. Extensive modifications were necessary to consider the aerodynamic and physical characteristics of polydisperse aerosols. Effects as sedimentation, deposition, resuspension and agglomeration of aerosols are or will be integrated into the simulation model. In order to realize a validation of such a complex dispersion model, our research group is developing two independent aerosol tracer systems. Primary attention is paid to the environmental compatibility of the tracer dust. Both procedures are based on fluorescence marked particles, but they differ from each other with regard to their methods of detection. This enables us to practice both procedures at the same time. The dispersion model as well as the validation methods is objects of this paper

Two-dimensional Anderson-Hubbard model in DMFT+Sigma approximation

Density of states, dynamic (optical) conductivity and phase diagram of paramagnetic two-dimensional Anderson-Hubbard model with strong correlations and disorder are analyzed within the generalized dynamical mean-field theory (DMFT+Sigma approximation). Strong correlations are accounted by DMFT, while disorder is taken into account via the appropriate generalization of the self-consistent theory of localization. We consider the two-dimensional system with the rectangular "bare" density of states (DOS). The DMFT effective single impurity problem is solved by numerical renormalization group (NRG). Phases of "correlated metal", Mott insulator and correlated Anderson insulator are identified from the evolution of density of states, optical conductivity and localization length, demonstrating both Mott-Hubbard and Anderson metal-insulator transitions in two-dimensional systems of the finite size, allowing us to construct the complete zero-temperature phase diagram of paramagnetic Anderson-Hubbard model. Localization length in our approximation is practically independent of the strength of Hubbard correlations. However, the divergence of localization length in finite size two-dimensional system at small disorder signifies the existence of an effective Anderson transition.Comment: 10 pages, 10 figures, improve phase diagra

Small Disks and Semiclassical Resonances

We study the effect on quantum spectra of the existence of small circular disks in a billiard system. In the limit where the disk radii vanish there is no effect, however this limit is approached very slowly so that even very small radii have comparatively large effects. We include diffractive orbits which scatter off the small disks in the periodic orbit expansion. This situation is formally similar to edge diffraction except that the disk radii introduce a length scale in the problem such that for wave lengths smaller than the order of the disk radius we recover the usual semi-classical approximation; however, for wave lengths larger than the order of the disk radius there is a qualitatively different behaviour. We test the theory by successfully estimating the positions of scattering resonances in geometries consisting of three and four small disks.Comment: Final published version - some changes in the discussion and the labels on one figure are correcte

Expression of the Three Alternative Forms of the Sphingolipid Activator Protein Precursor in Baby Hamster Kidney Cells and Functional Assays in a Cell Culture System

Sphingolipid activator proteins (SAPs) are non-enzymatic glycoproteins required for lysosomal degradation of various sphingolipids with short oligosaccharide chains by their respective exohydrolases. Four of these (SAP-A to SAP-D or saposins A to D) are derived from a common precursor by proteolytic processing. Alternative splicing of the SAP-precursor gene results in insertion of additional 6 or 9 bases of exon 8' or 8, respectively, into the SAP-B coding region of the transcribed mRNAs. To examine the features of the three different SAP-precursor proteins (prosaposins), the respective cDNAs were stably expressed in baby hamster kidney cells. Pulse-chase experiments with transfected cells and endocytosis studies on human fibroblasts showed that synthesis, transport, and maturation of all SAP-precursor led to formation of the four mature SAPs (SAP-A to SAP-D). In order to determine the biological function of the three different SAP-B isoforms, SAP-precursor-deficient human fibroblasts were loaded with recombinant SAP-precursor proteins with or without 2- and 3-amino acid insertions, respectively, purified from the medium of the baby hamster kidney cells. They were found to stimulate at nanomolar concentrations the turnover of biosynthetically labeled ceramide, glucosylceramide, and lactosylceramide. Since the physiological function of SAP-B is to stimulate the degradation of sulfatide by arylsulfatase A (EC 3.1.6.1) and globotriaosylceramide by beta-galactosidase (EC 3.2.1.23) loading studies with the respective exogenously labeled lipids on SAP-precursor-deficient fibroblasts were performed. Addition of different purified SAP-precursors to the medium of the lipid-loaded fibroblasts showed positive stimulation of the lipid degradation by all three SAP-B isoforms derived from the SAP-precursors. These findings establish that all three forms of the SAP-B can function as sulfatide/globotriaosylceramide activator