TU Dortmund University
Eldorado - Ressourcen aus und für Lehre, Studium und ForschungNot a member yet
19914 research outputs found
Sort by
Zwanzigeins - Empirische Studie zur Transkodierung zweistelliger Zahlen in inverser und stellenwertgerechter Sprechweise
No full textDeutsche Zahlwörter, wie einundzwanzig, entsprechen nicht der Schreibrichtung der Ziffernzahlen und dem Aufbau des Stellenwertsystems (erst Zehner, dann Einer). 506 Kinder der Schulstufen 1 bis 4 aus 30 österr. Grundschulen absolvierten Diktattests in traditioneller und unverdrehter Sprechweise mit Hilfe der Zwanzigeins-App (kontrolliertes randomisiertes 4-Perioden-Experiment mit balanciertem Crossover). Die Studie belegt hochsignifikante (p<0,00005) und pädagogisch relevante Vorteile einer stellenwertgerechten Sprechweise: Die Bearbeitungsdauer wurde um 10%, die Fehleranzahl um 66% reduziert
Innovation through networking: the single contact points for employers in the German vocational rehabilitation and participation system
No full textIntroduction: The German vocational rehabilitation and participation system is highly complex due to fragmented legal responsibilities and institutional structures. To address this and improve labor market inclusion for people with severe disabilities, Single Contact Points for Employers [Einheitliche Ansprechstellen für Arbeitgeber (EAA)] were established in 2022. The EAA are legally mandated, provider-independent entities that support employers in hiring and retaining employees with disabilities. The article analyzes the network structure of the EAA within the vocational rehabilitation and participation system, how the structure is evaluated, and which partners are most relevant to the EAA.
Methods: A network analysis was conducted through egocentric network maps (N = 20) with EAA consultants, online surveys of EAA consultants (N = 18), and their key network partners (N = 123). Additionally, N = 7 guided expert interviews (5 with employers, 2 with EAA supervisors) and three focus groups of 3–6 people each (1 with EAA consultants, 1 with EAA supervisors, and 1 with network partners) were analyzed using qualitative content analysis to assess the structure and quality of cooperation.
Results: The EAA work closely with policy actors from the vocational rehabilitation and participation system who provide advice and services for participation in work, such as Integration Services, Employment Agencies, and Specialist Agencies. These collaborations are characterized by mutual information exchange and generally positive cooperation. Actors from the economy, civil society, and academic sector are underrepresented in the EAA's overall network. Employers’ associations were rarely named as key partners, and civil society organizations were absent.
Discussion: The EAA's strong integration into policy networks underscores their institutional relevance. However, their limited ties to economic and civil entities suggest a constrained capacity for innovation. This pattern reflects both the strengths of their legal mandate and the challenges of acting independently within a highly structured system. Expanding their relational scope could foster more holistic solutions for inclusive employment
Determination of GISSMO Damage Parameters for High-Speed Blanking of 22MnB5 and EN AW-5754
No full textHigh-speed blanking (HSB) of high-strength materials, such as the steel 22MnB5, is an
established method that delivers high-quality cut surfaces. Due to high shear rates, this
process is associated with the formation of adiabatic shear bands (ASB) in the blanking
zone. For an in-depth analysis of the effects arising in this process and to support the
prototyping of blanking tools, a numerical simulation is required. For this purpose, material
parameters, which are valid at elevated strain rates are necessary. In this study, the
parameter identification for the GISSMO damage model is presented. For the parameter
identification, a series of coupled experimental and numerical investigations were carried
out on 22MnB5 and EN AW-5754 with a sheet thickness of 2 mm. The main objective was to
determine the damage and failure behaviour of the investigated materials under different
loading modes (or triaxialities). The resulting data was used as input for the subsequent
optimisation of the parameters in LS-DYNA and LS-OPT
Effect of crystal symmetry of lead halide perovskites on the optical orientation of excitons
No full textThe great variety of lead halide perovskite semiconductors represents an outstanding platform for studying crystal symmetry effects on the spin-dependent properties. Access to them is granted through the optical orientation of exciton and carrier spins by circularly polarized photons. Here, the exciton spin polarization is investigated at 1.6 K cryogenic temperature in four lead halide perovskite crystals with different symmetries: (almost) cubic in FA0.9Cs0.1PbI2.8Br0.2 and FAPbBr3, and orthorhombic in MAPbI3 and CsPbBr3. Giant optical orientation of 85% is found for the excitons in FA0.9Cs0.1PbI2.8Br0.2, MAPbI3, and CsPbBr3, while it amounts to 20% in FAPbBr3. For all studied crystals, the optical orientation is robust to detuning of the laser photon energy from the exciton resonance, remaining constant for high energy detunings up to 0.3 eV, above which it continuously decreases to zero for detunings exceeding 1 eV. No acceleration of the spin relaxation for excitons with large kinetic energy is found in the cubic and orthorhombic crystals. This evidences the absence of the Dyakonov-Perel spin relaxation mechanism, which is based on the Rashba-Dresselhaus splitting of spin states at finite k-vectors. This indicates that the spatial inversion symmetry is maintained in perovskite crystals, independent of the cubic or orthorhombic phase
Proposing critical realism and second-generation environmental justice for advancing sacrifice zone analysis
No full textThis article addresses the complex social-ecological challenges faced by sacrifice zones—territories subjected to severe environmental degradation and social injustices. Traditional environmental justice research, with its emphasis on distributive justice, often fails to capture the intricate dynamics of these often not-recognized areas. In light of these limitations, this article proposes a second-generation environmental justice approach, employing a critical realist paradigm, to identify sacrifice zones and explore their deeper causal mechanisms. This approach, which transcends the distributional focus of traditional research, reveals mechanisms commonly observed in these zones. These mechanisms enable and sustain environmental degradation and social injustices through dynamics such as economic exploitation, policy failures, and power imbalances. Intertwined within social-ecological systems, these dynamics create cycles of poverty, health disparities, and ecological harm. Moreover, the article offers a methodological reflection on the theoretical proposal and planning practices toward environmental justice. It concludes with recommendations for future research, emphasizing the importance of systemic change and inclusive policy-making to achieve environmental justice and sustainability
Portfolio als Prüfungsform für mathematisches Modellieren mit digitalen Werkzeugen
No full textMathematisches Modellieren mit digitalgestützten Aufgaben kann in klassischen Prüfungsformaten wie Klassenarbeiten nur schwer überprüft werden. In einer qualitativen Interviewstudie wurde das Portfolio als alternatives Prüfungsformat untersucht. Dazu wurde ein Unterrichtsvorhaben in der 9. Klasse durchgeführt, bei dem Schüler*innen Modellierungstätigkeiten in einem Portfolio dokumentierten. Sie nahmen sowohl Vorteile (z.B. Zeit, Kooperation, weniger Leistungsdruck) als auch Herausforderungen (z.B. Aufwand, Kooperation, Zeit, Schwierigkeiten beim Modellieren) bei der Prüfungsform wahr
Science PR
No full textIn the competition for reputation and resources, public relations (PR) has become increasingly important for scientific institutions. This article examines the legitimation function of science PR for universities and research institutions in Germany against the background of a controversial case of science PR. It illuminates the underlying reasons for the conflictual nature of science PR, proposes potential guidelines for its conduct, and delineates the boundaries to science journalism. Finally, it argues for placing trusting relationships at the heart of science PR
Professionalisierung für nachhaltigen Verständnisaufbau: Sequenzierung von Aktivitäten in asynchronen Fortbildungen
No full textIn der vorgestellten asynchronen Fortbildung kombinieren wir beide Formate in Moodle-Aktivitäten miteinander und in dem Beitrag wird folgende Forschungsfrage untersucht: Wie kann die Sequenzierung von unterschiedlichen Moodle-Aktivitäten zur Lehrkräfteprofessionalisierung aussehen, die den Verständnisaufbau im Blick hat? In dem Beitrag wird gezeigt, wie eigene Denkmomente beispielsweise in Freitextfeldern mit der geschlossenen Auseinandersetzung mit gegebenen Praktiken kombiniert werden können
Analysis of Shear Localization in High-Speed Blanking of Press-Hardened 22MnB5 Steel
No full textHigh-speed blanking induces a shear localization in high-strength steels, improving the
quality of the blanked edge in terms of geometrical shape, separation surface roughness,
and shear-influenced zone close to the cut edge. High-speed blanking experiments with a
20 mm punch diameter and 8 m/s velocity of 2 mm thick 22MnB5-sheets (ultimate tensile
strength of 1550 MPa) utilizing a relative clearance of 2.5 % are carried out. Two types of
shear bands are observed in the post-process: A 'deformation shear band,' characterized by
elongated grains in shear direction, is distinguished from a ‘transformation shear band’
with a change in microstructure appearing as a white layer in optical microscopy. Previous
investigations by transmission electron microscopy showed that this white layer consists of
nanosized grains in 22MnB5 material. Light microscopic images show that the transfor mation
shear band width varies over the sheet thickness. Independent of the occurrence of a
transformation shear band, a localization with a width of less than 20 µm is observed along
the blanked edge. Fractographic analysis by scanning electron microscopy shows no evi dence
of brittle fracture. Characteristic areas of the separation surfaces coincide with the
observed two types of shear bands at the blanked edg
Verstärkt der Einsatz digitaler Tools die Wirkung von gutem Unterricht? – Eine Analyse zur Mathematikleistung in der Sekundarstufe
No full textMetaanalysen berichten meist von positiven Effekten digitaler Tools auf Mathematikleistungen, basierend auf experimentellen Studien in kontrollierten Settings. Doch wie wirken sie im normalen Unterrichtsalltag, in dem Lehrkräfte die Tools eigenständig auswählen – und wie hängt dies mit der Unterrichtsqualität zusammen? Längsschnittdaten aus 83 Klassen (8. Jgst.) zeigen: Der Einsatz digitaler Tools geht mit einem signifikant niedrigeren Lernerfolg einher, der nur durch hohe Klassenführung und Schülerunterstützung kompensiert werden kann. Auch die kognitive Aktivierung wird näher beleuchtet