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[Rezension zu:] Alfred Hiatt, Dislocations. Maps, Classical Tradition, and Spatial Play in the European Middle Ages (Studies and Texts 218). Toronto, Pontifical Institute of Mediaeval Studies. Turnhout, Brepols 2020. XII, 347 S. 42 farb. Abb.
(2023-07-06)
Rezension von Ingrid Baumgärtner zu: Alfred Hiatt, Dislocations. Maps, Classical Tradition, and Spatial Play in the European Middle Ages (Studies and Texts 218). Toronto, Pontifical Institute of Mediaeval Studies. Turnhout, Brepols 2020. XII, 347 S. 42 farb. Abb.
Masterarbeit
Analysis and Method Selection of a Measure-Correlate-Predict Methodology for a Digital Wind Buoy
(2022)
The determination of the site-specific wind conditions has a significant influence on the development and use of offshore wind energy. Lower uncertainties of wind potential result in cost-effective project financing. Floating lidar systems (FLS) or wind lidar buoys have become increasingly common in recent years as a measuring technology for the determination of offshore wind resource. However, due to harsh offshore environmental conditions, offshore measurements with FLS are prone to reliability issues which might ...
Aufsatz
On the Influence of Surface Hardening Treatments on Microstructure Evolution and Residual Stress in Microalloyed Medium Carbon Steel
(2020-06-09)
Tailoring surface properties is a key to superior performance of components subjected to fatigue loadings in application. Process–microstructure–property relationships have to be established to allow for optimization of techniques employed for surface treatments such as deep rolling and induction hardening. Although both techniques are employed widely in industrial application, studies examining microstructure evolution and residual stress states for a single material in a comparative manner are missing. Amongst ...
Aufsatz
Cooling rate as a process parameter in advanced roll forming to tailor microstructure,mechanical and corrosion properties of EN AW 7075 tubes
(2022-12-14)
The effects of solution heat treatment parameters and quench media as a processing tool for tailoring microstructure, mechanical and corrosion properties in roll forming of EN AW 7075 alloy were studied. The highest yield stress and ultimate tensile strength were obtained for the specimens quenched in water, while the air-cooled specimens exhibited inferior mechanical properties. Microstructural analysis of specimens showed that except water-quenched specimens, the parts cooled/quenched in oil, in direct contact with ...
Aufsatz
Influence of Microstructure and Defects on Mechanical Properties of AISI H13 Manufactured by Electron Beam Powder Bed Fusion
(2021-08-04)
Electron beam powder bed fusion (E-PBF) is a well-known additive manufacturing process. Components are realized based on layer-by-layer melting of metal powder. Due to the high degree of design freedom, additive manufacturing came into focus of tooling industry, especially for tools with sophisticated internal cooling channels. The present work focuses on the relationships between processing, microstructure evolution, chemical composition and mechanical properties of a high alloyed tool steel AISI H13 (1.2344, ...
Aufsatz
Evaluation of extremely steep residual stress gradients based on a combined approach using laboratory-scale equipment
(2021-11-30)
Surface treatments characterized by rapid heating and cooling (e.g. laser hardening) can induce very steep residual stress gradients in the direct vicinity of the area being treated. These gradients cannot be characterized with sufficient accuracy by means of the classical sin2Ψ approach applying angle-dispersive X-ray diffraction. This can be mainly attributed to limitations of the material removal method. In order to resolve residual stress gradients in these regions without affecting the residual stress equilibrium, ...
Aufsatz
On the Impact of Build Envelope Sizes on E-PBF Processed Pure Iron
(2021-11-17)
In additive manufacturing, the thermal history of a part determines its final microstructural and mechanical properties. The factors leading to a specific temperature profile are diverse. For the integrity of a parameter setting established, periphery variations must also be considered. In the present study, iron was processed by electron beam powder bed fusion. Parts realized by two process runs featuring different build plate sizes were analyzed. It is shown that the process temperature differs significantly, ...
Aufsatz
A Novel Thermo-Mechanical Processing Route Exploiting Abnormal Grain Growth in Heusler-Type Co–Ni–Ga Shape Memory Alloys
(2022-10-04)
Heusler-type Co–Ni–Ga shape memory alloys attracted significant scientific attention owing to excellent superelasticity in single-crystalline state. However, due to pronounced anisotropy, polycrystalline Co–Ni–Ga suffers from transformation-induced constraints at grain boundaries and, thus, premature failure upon thermo-mechanical loading. The present study reports on a novel thermo-mechanical processing route. Hot rolling followed by solution-annealing promotes abnormal grain growth, eventually leading to high-performance ...
Working paper
Mathematical Management
(2023-07-14)
Der Aufstieg des Fachgebietes Operations Research, das mathematische Modelle zur Steuerung von Wirtschaftsunternehmen bereitstellt, in der politischen Wissenskultur von Cold War Science der USA nach 1945 wird aufgezeigt und dann übergeleitet zur Institutionalisierung von Operations Research in den Universitäten von Europa und der Bundesrepublik Deutschland. Die Vorläuferorganisationen zur Deutschen Gesellschaft für Operations Research werden dargestellt und das Zusammenspiel der Jahrestagung dieser Gesellschaft mit ...
Working paper
One Way Logistics in Freight Transport
(2022)
The European railroad companies founded the International Container Bureau in Paris in 1933. The Swiss company Hupac successfully developed container transport with transalpine freight transport by rail between Germany and Italy. In the 1930s, Europe and the U.S. had agreed on a common ISO standard for 20 foot containers and 40 foot containers, so that empty containers could be exchanged between the various shipping companies in the global supply chains. But this standard is not compatible with the metric system of ...