TU Dortmund University
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Mathetag - Transformation von der Uni in die Schule
No full textAls Möglichkeit Praxis zu erleben und für den eigenen Unterricht nutzbar zu machen, wurde im Rahmen einer Begleitlehrveranstaltung zum Schulpraktikum Mathematik „Ein Mathetag“ konzipiert. In verschiedenen Stationen wird Studierenden die Bedeutung der Verbindung von fachdidaktischem und fachlichem Wissen für den Unterrichtstransfer verdeutlicht. Eine Lesson Study begleitet den Mathetag, um zu untersuchen, wie er das Verständnis für Theorie-Praxis-Verknüpfungen stärkt und innovative Lehrmethoden für das eigene Lernen sowie den Mathematikunterricht nutzbar macht
Grain Boundary Motion in Magnetic-Pulse-Welded Al-Fe Bimetal Systems: An Atomistic Simulation Study
No full textMagnetic pulse welding (MPW) is an ef ective solid-state welding method of joining
dissimilar metals such as Al/Steel, Al/Ti, Al/Cu et al. In order to understand fully such
important phenomena as atomic dif usion, grain boundary motion, interfacial
non- equilibrium-phase nucleation and growth in MPW, a detailed microscopic description of
the MPW interface is necessary. This study is an extension of our previous work. In the
present work, we extend the simulation investigation to polycrystal aluminium and iron
systems using Molecular dynamic (MD) method. The polycrystal systems allow for the
study of interfacial segregation. Our simulations present structural information on the GBs
in nanocrystalline microstructures. Flat GBs can move when subjected dynamic load
resulting from the high-velocity impact. Plots of the ratio of GB atoms versus time show a
distinctly dif erent GB migration behaviors between loading and unloading conditions. By
contrast with our earlier simulations, it was observed that crystal order and stability are
highly preserved in the loading stage. The transformation of grain boundary structural
change is due to stress-driven GB migration and temperature dependent as well. Grain
rotation mechanism was identified. This work could provide atomistic insights into the
grain refinement during MPW process
Aus dem echten Leben? Untersuchungen zur Authentizität in realitätsbezogenen Testaufgaben
No full textFür den Mathematikunterricht sind Realitätsbezüge von großer Bedeutung. Im Zusammenhang mit realitätsbezogenen Aufgaben wird Authentizität hierbei regelmäßig als zentrales Aufgabenkriterium eingefordert. Ziel der vorliegenden Studie ist es, das Konstrukt der Authentizität besser zu verstehen. Dazu werden realitätsbezogene Testaufgaben aus VERA-8 daraufhin untersucht, inwieweit sie authentische Aspekte enthalten und welche Zusammenhänge zu allgemeinen Merkmalen qualitativ hochwertiger Testaufgaben bestehen
Lifespan and learning perspectives on work design
No full textThis dissertation examines how work design can address the challenges of an aging workforce and increasing learning demands while promoting employee health, informal workplace learning, and occupational future time perspective. From a lifespan perspective, the literature review reveals age-specific differences in the relationships between psychosocial job characteristics and individual health, underscoring the need for age-sensitive work design. From a learning perspective, the conceptual study shows how telework alters opportunities for informal workplace learning and highlights how supervisors can support it by designing work characteristics and learning processes. From an integrated lifespan and learning perspective, the empirical study examines job-related and personal antecedents of occupational future time perspective and the role of job crafting, emphasizing reciprocal and dynamic relationships between work design and self-regulation. Overall, the findings demonstrate that future-oriented work design should be age-sensitive, learning-oriented, and adaptive to support continuous learning and successful aging at work
A Novel Coil Structure for Metal Sheet Magnetic Pulse Welding
No full textMagnetic pulse welding (MPW) of metal sheets is an efficient and environment-friendly
room temperature solid-state welding technology. However, the process involves significant
energy dissipation. Limited by the current coil structure, high energy is required to achieve
metallurgical welding of metal sheets. To address this issue, novel coil principle and
structure has been proposed. The current is simultaneously concentrated into a section of
conductor by a unique circuit design, achieving current summation and amplification,
thereby enhancing energy efficiency. Numerical simulations were performed to explore the
effects of coil parameters on current density, Lorentz force, and flyer sheet motion, revealing
that the coil structure can amplify current by 1.5 to 5.3 times as coil turns increase from 2 to
7. The flyer sheet velocity exceeded the critical welding velocity. Experimental results show
successful welding of 1060 (1.0 mm) / DP450 (1.0 mm) at 6.05 kJ and 5754 (1.0 mm) /
DP600 (1.0 mm) at 9.8 kJ, with all interfaces displaying metallurgical characteristics. These
findings confirm the excellent welding capability of the novel coil at low energy, which
results from a significant current amplification effect. This reduces the stringent
requirements for magnetic pulse discharge equipment, thereby facilitating the further
industrial application of MPW technology
Zusammenhang von sprachlichem und arithmetischem Lernen im Förderschwerpunkt Sprache
No full textDer Vortrag zeigt auf, wie sich die vier linguistischen Ebenen Aussprache, Wortschatz, Grammatik und Kommunikation auf das arithmetische Lernen auswirken können. Dies wird anhand von Beispielen aus einem Projekt zum Beschreiben von Rechenwegen von Lernenden mit Förderschwerpunkt Sprache gezeigt
Problemlösen bewerten – Eine Studie zum Einsatz von Beurteilungsrastern zur Bewertung von Problemlöseprodukten
No full textDie Bewertung von Problemlöseprodukten im Mathematikunterricht ist herausfordernd, da verschiedene Lösungswege und Leistungsniveaus berücksichtigt werden müssen. Beurteilungsraster bieten einen Rahmen, der eine objektive, valide und reliable Bewertung ermöglichen soll. In Bezug auf Beurteilungsraster für das Problemlösen fehlen jedoch noch aussagekräftige empirische Befunde. Mit einem speziell entwickelten Beurteilungsrasters soll untersucht werden, inwieweit dessen Nutzung eine objektive und vergleichbare Beurteilung von Problemlöseprodukten durch unterschiedliche Lehrkräfte ermöglicht
TCAD simulation of stitching for passive CMOS strip detectors
No full textMost of the tracking detectors for high energy particle experiments are filled with silicon detectors since they are radiation hard, they can give very small spatial resolution and they can take advantage of the silicon electronics foundries' developments and production lines. Strip detectors are very useful to cover large areas for tracking purposes, while consuming less power per area compared to pixel sensors. The majority of particle physics experiments use conventional silicon strip detectors fabricated in foundries that do not use stitching, relying on a very small number of foundries worldwide that can provide large amounts of strip detectors. Fabricating strip detectors in a CMOS foundry opens the possibility to use more foundries and to include active elements in the strips for future productions. For the passive CMOS strip detectors project we fabricated strip detectors in a CMOS foundry using two 1 cm2 reticles that are stitched together along the wafer. The fabricated strips stitched the reticles three and five times, and it was shown that the performance of those strips is not affected by the stitching. This paper shows 3D TCAD simulations of the stitching area to investigate the possible effects stitching can have on the performance of the strip detectors, considering different stitching mismatches. We will show that the mismatch of stitched structures up to 1 µm does not impact the performance with TCAD simulations which agrees with the results obtained from the measurements