Bauhaus University, Weimar

About: Bauhaus University, Weimar is a education organization based out in Weimar, Thüringen, Germany. It is known for research contribution in the topics: Finite element method & Isogeometric analysis. The organization has 1421 authors who have published 2998 publications receiving 104454 citations. The organization is also known as: Bauhaus-Universität Weimar & Hochschule für Architektur und Bauwesen.

A new technique for measuring broadband dielectric spectra of undisturbed soil samples

Abstract: A new coaxial line cell for the determination of dielectric spectra of undisturbed soil samples was developed based on a 1.625-inch - 50 Ω coaxial system. Undisturbed soil samples were collected from a soil profile of the Taunus region (Germany) and capillary saturated followed by a step-by-step de-watering in a pressure plate apparatus as well as oven-drying at 40°C. The resultant water contents of the soil samples varied from saturation to air-dry. Permittivity measurements were performed within a frequency range from 1 MHz to 10 GHz with a vector network analyser technique. Complex effective relative permittivity or electrical conductivity was obtained by combining quasi-analytical and numerical inversion algorithms as well as the parameterizing of measured full set S-parameters simultaneously under consideration of a generalized fractional dielectric relaxation model (GDR). The measurement of standard materials shows that the technique provides reliable dielectric spectra up to a restricted upper frequency of 5 GHz. For the soil samples investigated, the real part of complex effective relative permittivity ɛ′r,eff and the real part of complex effective electrical conductivity σ′eff decreased with increasing matric potential or decreasing water contents. Soil texture and porosity affect the dielectric behaviour at frequencies below 1 GHz. For frequencies above 1 GHz minor texture effects were found. The presence of organic matter decreases ɛ′r,eff and σ′eff. At 1 GHz, the empirical model of Topp et al. (1980) is in close agreement with the experimentally determined real part of the effective permittivity with RMSEs ranging from 1.21 for the basal periglacial slope deposit and 1.29 for bedrock to 3.93 for the upper periglacial slope deposit (Ah). The comparison of the experimental results with a semi-empirical dielectric mixing model shows that data, especially for the organic-free soils, tend to be under-estimated below 1 GHz. The main advantage of the new method compared with conventional impedance and coaxial methods is the preservation of the natural in-situ structure and properties such as bulk density of the investigated soil samples.

Effects of the dispersion of polymer wrapped two neighbouring single walled carbon nanotubes (SWNTs) on nanoengineering load transfer

Abstract: German Federation of Materials Science and Engineering (BV MatWerk); German Research Foundation (DFG); National Natural Science Foundation of China (Microscale grinding and micromilling-grinding compound machining process) [52075064]

Finger and hand detection for multi-touch interfaces based on maximally stable extremal regions

Abstract: We propose a new approach for touch detection on optical multi-touch devices that exploits the fact that the camera images reveal not only the actual touch points, but also objects above the screen such as the hand or arm of a user. Our touch processing relies on the Maximally Stable Extremal Regions algorithm for finding the users' fingertips in the camera image. The hierarchical structure of the generated extremal regions serves as a starting point for agglomerative clustering of the fingertips into hands. Furthermore, we suggest a heuristic supporting the identification of individual fingers as well as the distinction between left hands and right hands if all five fingers of a hand are in contact with the touch surface.Our evaluation confirmed that the system is robust against detection errors resulting from non-uniform illumination and reliably assigns touch points to individual hands based on the implicitly tracked context information. The efficient multithreaded implementation handles two-handed input from multiple users in real-time.