451 research outputs found

    Bewerbung um den Landeslehrpreis 2005 für das Seminar "Erstellung psychologischer Lehrfilme"

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    In dieser Bewerbung um den Landeslehrpreis 2005 wird die didaktische Konzeption eines Seminars zur "Erstellung psychologischer Lehrfilme" dargestellt. In diesem projektorientierten Seminar zur Vermittlung psychologischer und mediengestalterischer Kompetenzen wird der "Perspektivenwechsel" als zentrales Element eingesetzt. Die Studierenden und ihre Dozenten setzen sich wissenschaftlich, filmend, schauspielernd und medienproduzierend mit ihren Fragestellungen auseinander. Diese didaktische Konzeption ist nicht nur im Bereich Psychologie umsetzbar, sondern ebenso in anderen Lehrgebieten

    Multistable setups combining magnetic shape memory alloys with reluctance counterforces

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    Systems with the ability to hold a given position without consumption of energy, i.e. multistability, can be employed in a variety of applications. Apart from the most commonly frictionbased systems, smart materials are an option to create multistability. Here, the ability to create a multistable system from magnetic shape memory alloy (MSM) in a magnetic field, combined with a reluctance counterforce is discussed. For the approach the necessary design process is described, as well as the experimental characterization of a demonstrator system. With the multistable range of the stroke at 0.82 mm and an average resistance to disturbance of ±10 N, two key parameters of the multistable properties are determined. As an outlook, potential applications in the design of adaptable interfaces is discussed

    The first conformal Dirac eigenvalue on 2-dimensional tori

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    Let M be a compact manifold with a spin structure \chi and a Riemannian metric g. Let \lambda_g^2 be the smallest eigenvalue of the square of the Dirac operator with respect to g and \chi. The \tau-invariant is defined as \tau(M,\chi):= sup inf \sqrt{\lambda_g^2} Vol(M,g)^{1/n} where the supremum runs over the set of all conformal classes on M, and where the infimum runs over all metrics in the given class. We show that \tau(T^2,\chi)=2\sqrt{\pi} if \chi is ``the'' non-trivial spin structure on T^2. In order to calculate this invariant, we study the infimum as a function on the spin-conformal moduli space and we show that the infimum converges to 2\sqrt{\pi} at one end of the spin-conformal moduli space.Comment: published version (typos removed, bibliography updated

    Chondrosarcoma of the Pelvis: Oncologic and Functional Outcome

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    Purpose. Chondrosarcoma (CS) most commonly involves the pelvis. The factors that influence local and systemic control of pelvic CS and the functional outcome should be evaluated

    Fast and robust detection of solar modules in electroluminescence images

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    Fast, non-destructive and on-site quality control tools, mainly high sensitive imaging techniques, are important to assess the reliability of photovoltaic plants. To minimize the risk of further damages and electrical yield losses, electroluminescence (EL) imaging is used to detect local defects in an early stage, which might cause future electric losses. For an automated defect recognition on EL measurements, a robust detection and rectification of modules, as well as an optional segmentation into cells is required. This paper introduces a method to detect solar modules and crossing points between solar cells in EL images. We only require 1-D image statistics for the detection, resulting in an approach that is computationally efficient. In addition, the method is able to detect the modules under perspective distortion and in scenarios, where multiple modules are visible in the image. We compare our method to the state of the art and show that it is superior in presence of perspective distortion while the performance on images, where the module is roughly coplanar to the detector, is similar to the reference method. Finally, we show that we greatly improve in terms of computational time in comparison to the reference method

    High Strain Rate and Stress-State-Dependent Martensite Transformation in AISI 304 at Low Temperatures

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    Deformation-induced martensitic transformation as the basis of a hardening process is dependent, among others, on the stress state. In applications such as cryogenic cutting, where a hardened martensitic subsurface can be produced in metastable austenitic steels, different stress states exist. Furthermore, cutting typically occurs at high strain rates greater than 103s−1. In order to gain a deeper insight into the behavior of a metastable austenitic steel (AISI 304) upon cryogenic cutting, the influence of high strain rates under different loading conditions was analyzed. It was observed that higher strain rates lead to a decrease in the α′-martensite content if exposed to tensile loads due to generated adiabatic heat. Furthermore, a lath-like α′-martensite was induced. Under shear stress, no suppression of α′-martensite formation by higher strain rates was found. A lath α′-martensite was formed, too. In the specimens that were subjected exclusively to compressive loading, almost no α′-martensite was present. The martensitic surface generated by cutting experiments showed deformation lines in which α′-martensite was formed in a wave-like shape. As for the shear specimens, more α′-martensite was formed with increasing strain rate, i.e., force. Additionally, magnetic etching proved to be an effective method to verify the transformation of ferromagnetic α′-martensite
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