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Aufsatz
Electron beam welding of Fe–Mn–Al–Ni shape memory alloy: Microstructure evolution and shape memory response
(2017-07-03)
The present study reports on the impact of abnormal grain growth (AGG) on the microstructural evolution following electron beam (EB) welding of Fe–Mn–Al–Ni shape memory alloy (SMA). Polycrystalline sheet-like material was EB-welded and a cyclic heat treatment, studied in previous work, was conducted for inducing AGG and a bamboo-like microstructure, respectively. Optical and electron microscopy were carried out to characterize the prevailing microstructure upon cyclic heat treatment. For characterization of the ...
Aufsatz
Time-of-Flight Three Dimensional Neutron Diffraction in Transmission Mode for Mapping Crystal Grain Structures
(2017-08-25)
The physical properties of polycrystalline materials depend on their microstructure, which is the nano- to centimeter scale arrangement of phases and defects in their interior. Such microstructure depends on the shape, crystallographic phase and orientation, and interfacing of the grains constituting the material. This article presents a new non-destructive 3D technique to study centimeter-sized bulk samples with a spatial resolution of hundred micrometers: time-of-flight three-dimensional neutron diffraction (ToF ...
Aufsatz
Aphyllophoroid fungi in insular woodlands of eastern Ukraine
(2017-12-22)
Background
Fungi play crucial roles in ecosystems and are among the species-richest organism groups on Earth. However, knowledge on their occurrence lags behind the data for animals and plants. Recent analyses of fungal occurrence data from Western, Central and Northern Europe provided important insights into response of fungi to global warming. The consequences of the global changes for biodiversity on a larger geographical scale are not yet understood. Landscapes of Eastern Europe and particularly of eastern ...
Aufsatz
Index-based agricultural insurance products: challenges, opportunities and prospects for uptake in sub-Sahara Africa
(Kassel University Press, 2017-07-25)
Agricultural insurance products have been piloted in Sub-Saharan Africa (SSA) to address climate related risks faced by farmers. However, these products in general face low rates of adoption in SSA. Factors and challenges that may explain the low uptake of index-based insurance products in SSA are reviewed in this paper with the objective of assessing and documenting (i) the insurance products available to farmers, (ii) factors influencing farmers to purchase insurance products, (iii) challenges limiting farmers ...
Aufsatz
Global Peasants Rights: International Congress 2017
(Department of Organic Food Quality and Food Culture at the University of Kassel, Germany and Federation of German Scientists (VDW), 2017-06)
“Reaffirming that all human rights are universal, indivisible, interrelated, interdependent and mutually reinforcing and must be treated in a fair and equal manner, on the same footing and with the same emphasis, and recalling that the promotion and protection of one category of rights should never exempt States from the promotion and protection of the other rights, recognizing the special relationship and interaction between peasants and other people working in rural areas, and the land, water, nature and territory ...
Aufsatz
Let’s twist again! Embodiment effects in spatial judgments on human figures rotated along a vertical axis
(2017)
We investigated whether individuals used mental rotation and embodiment for arm laterality judgments of human figures that were stepwise rotated from back view to front view along a vertical axis. In Experiment 1, figures’ heads were always shown in profile, while only the bodies were rotated. Judgments were faster and more correct when figures were presented in back view compared to front view, but the relation between reaction times (RTs) and rotation angles was not strictly linear. In addition, judgments on figures ...
Aufsatz
Energy Resolved Residual Stress Analysis with Laboratory X-Ray Sources
(2017-04-17)
It is well known that existing residual stress fields play an important role for strength and lifetime of components. Consequently there is a great interest in the availability of fast, reliable and possibly nondestructive methods for their determination. In this context, X-ray diffraction methods play an important role in technical practice as well as in scientific research. They are based on the determination of lattice strains from which residual stresses are determined applying Hooke's law with appropriate elastic ...
Aufsatz
Prozessintegration von induktiver Wärmebehandlung und Festwalzen – sichere und zuverlässige Komponenten mit hoher Schwingfestigkeit
(2017-02-08)
Mechanische Oberflächenbehandlungen, beispielsweise das Festwalzen, spielen in der technischen Praxis eine bedeutende Rolle und tragen wesentlich zur Steigerung der Zuverlässigkeit hochbeanspruchter Komponenten bei. In einer Reihe von Fällen wurde gezeigt, dass eine Erhöhung der Prozesstemperatur die Wirksamkeit der Verfahren noch steigert, weil dies zu einer besseren Stabilisierung der eingebrachten Druckeigenspannungen führt. Eine wesentliche Voraussetzung zur Einführung dieser Verfahren in die Praxis ist allerdings, ...
Aufsatz
Bend Straightening of a Carbonitrided Gear Shaft – Consequences on Residual Stresses and Retained Austenite near the Surface
(2017-06-20)
Carbonitriding of shafts in drive technology is strongly connected with distortion. Bend straightening is an important process step in order to eliminate distortion without removing the hardened surface layer. As shown in several investigations, even for simple part geometries, bending induced stresses and plastic deformations have a strong impact not only on the residual stress state but also on the microstructure after straightening. As gear shafts become increasingly filigree and complex in their geometry, the ...
Aufsatz
Investigations on Tightness of Polymer-Metal Hybrids in Environments with Thermal, Media, and Mechanical Loads
(2017-07-31)
With polymer-metal hybrids becoming more commonly used as structural components it was investigated how they perform in complex environments with combined thermal, media, and mechanical loads. Special attention was put on media tightness under said loads. This paper sums up the activities of the polymer technology research group of the University of Kassel on hybrids produced by overmolding metal inserts. Investigations concerning joint strength and influence of (cyclic) temperature loads and chemical corrosion on ...