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Aufsatz
CuCrZr processed by laser powder bed fusion — Processability and influence of heat treatment on electrical conductivity, microstructure and mechanical properties
(2021-06-16)
CuCrZr parts were fabricated by laser beam powder bed fusion (LB-PBF) technique and subjected to different heat treatments. As a result, four different conditions were considered for further investigations, that is, the as-built condition, conditions of maximum hardness (MH) and maximum electrical conductivity (MC), and a condition representing a compromise between hardness and conductivity (H&C). Microstructural evolution and performance under monotonic and cyclic loading were studied. Fracture surfaces revealed ...
Aufsatz
Characterization of Mechanical Properties, Macroscopic Deformation Behavior, and Microstructure of Functionally Graded 22MnB5 Steel
(2021-03-24)
The focus of this study is on the characterization of the local plastic deformation and failure of functionally graded 22MnB5 plates after hot stamping using an in situ approach. Various forming strategies at elevated temperatures are performed using differentially tempered forming tools to locally tailor the microstructure. By controlling the cooling rate, graded as well as martensitic and ferritic–pearlitic microstructures are obtained. Experimental analysis includes evaluation of the material- and geometry-dependent ...
Aufsatz
On the Microstructural and Cyclic Mechanical Properties of Pure Iron Processed by Electron Beam Melting
(2021-03-10)
Additive manufacturing (AM) processes such as electron beam melting (EBM) are characterized by unprecedented design freedom. Topology optimization and design of the microstructure of metallic materials are enabled by rapid progress in this field. The latter is of highest importance as many applications demand appropriate mechanical as well as functional material properties. For instance, biodegradable implants have to meet mechanical properties of human bone and at the same time guarantee adequate cytocompatibility ...
Aufsatz
On the Influence of Microstructure on the Corrosion Behavior of Fe–Mn–Al–Ni Shape Memory Alloy in 5.0 wt% NaCl Solution
(2020-10-03)
Herein the corrosion behavior of Fe–Mn–Al–Ni shape memory alloys characterized by different microstructures in a 5.0 wt% NaCl solution is investigated. Open circuit potential and potentiodynamic polarisation tests are conducted. Generally, Fe–Mn–Al–Ni shows corrosion properties being similar to pure iron. However, the polarization curves of single crystals indicate the presence of an unstable passive system. The corrosion damage is analyzed by means of optical microscopy and electron microscopy. It is revealed that ...
Aufsatz
Thermal Stability of Residual Stresses in Differently Deep Rolled Surface Layers of Steel SAE 1045
(2021-05-07)
The stability of compressive residual stresses generated by deep rolling plays a decisive role on the fatigue behavior of specimens and components, respectively. In this regard, deep rolling at elevated temperature has proven to be very effective in stabilizing residual stresses when fatigue analysis is conducted at ambient temperature. However, since residual stresses can be affected not only by plastic deformation but also when thermal energy is provided, it is necessary to analyze the influence of temperature and ...
Dissertation
Existence and Asymptotic Behavior of Solutions to the Time-Periodic Navier-Stokes Equations in a Layer Domain with Nonhomogeneous Boundary Data
(2024)
This dissertation is dedicated to the analysis of the Navier-Stokes equations in a timeperiodic framework in the so-called layer domain Π = R2 × (0, 1), described by:
∂tu − νΔu + (u · ∇)u + ∇p = f in [0, T] × Π,
div u = 0 in [0, T] × Π,
u|∂Π = a for all t ∈ [0, T] ,
u|t=0 = u|t=T in Π.
The velocity field u and the pressure p are unknowns, while the external force f is prescribed. Challenges arise due to unboundedness of the layer Π and from introduction of a nonhomogeneous boundary condition a. The investigated ...
Teil eines Buches
Jenseits des Horizonts
(Schwabe Verlag, 2022)
Im Folgenden ist deshalb zu überlegen, was diesseits und was jenseits des kartografischen Horizonts damaliger Menschen lag, wie sich die Relationen zwischen beiden Zonen in Abhängigkeit von Zeit, visualisiertem Raum und vorhandenem Wissen verschoben und welche Relevanz dem jenseitig Gelegenen dabei zukam. Es ist also nach den Dynamiken am Horizont zu fragen, dem Suchen und Überschreiten, den Akten des Stabilisierens und Flexibilisierens, den erkenntnistheoretischen Voraussetzungen und den kulturellen Praktiken, die ...
Aufsatz
Consumers ’ perception of sustainable packaging in the food industry: An online experiment
(2022-01)
Consumers evaluate products and make purchasing decisions based on packaging and its sustainable aspects. This research investigated how different packages and their quality, eco-friendliness, expensiveness, and convenience affected consumers’ intentions to purchase. Our sample comprised 299 French consumers of muesli cereals. We conducted an online choice experiment to analyze and measure consumers’ perception of sustainable packaging, comparing three distinct experimental groups. Findings revealed that quality and ...
Aufsatz
Geschichtswissenschaft
(2021-07-15)
Die mittelalterliche Geschichte ist derzeit noch relativ fester Bestandteil des allgemeinen Geschichtsunterrichts, obwohl die zeitliche Differenzierung durch die Kompetenzorientierung in den Lehrplänen immer weiter zurückgedrängt wird. Anders als rein chronologisch-inhaltliche Lehrpläne bietet die Kompetenzorientierung jedoch grundsätzlich gute Möglichkeiten, ‚mittelalterliches‘ Material einzubauen. In den meisten geisteswissenschaftlichen Fakultäten existiert in der Regel – mit einigen Ausnahmen – eine eigene ...
Rezension
[Rezension zu:] Yossef Rapoport, Emilie Savage-Smith, Lost Maps of the Caliphs. Drawing the World in Eleventh-Century Cairo, Chicago (The University of Chicago Press) 2018, 368 p., ISBN 978-0-226-54088-7, USD 59,00.
(2022-12-21)
Rezension von Ingrid Baumgärtner zu: Yossef Rapoport, Emilie Savage-Smith, Lost Maps of the Caliphs. Drawing the World in Eleventh-Century Cairo, Chicago (The University of Chicago Press) 2018, 368 p., ISBN 978-0-226-54088-7, USD 59,00.