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Wünschenswerte Erschwernisse beim Lernen
(2015)
Der Beitrag beleuchtet didaktische Maßnahmen, die unter dem Begriff „Wünschenswerte Erschwernisse“ zusammengefasst werden. Diese Maßnahmen erschweren zwar kurzfristig das Lernen, langfristig aber fördern sie das Behalten und den Transfer des Gelernten. Vier dieser wünschenswerten Erschwernisse sind empirisch besonders gut belegt: 1) Das verteilte Lernen, 2) das verschachtelte Lernen, 3) der Testungseffekt und 4) der Generierungseffekt. Zu jeder dieser wünschenswerten Erschwernisse werden aktuelle Forschungsergebnisse ...
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Girls in detail, boys in shape: Gender differences when drawing cubes in depth
(2013)
The current study tested gender differences in the developmental transition from drawing cubes in two‐ versus three dimensions (3D), and investigated the underlying spatial abilities. Six‐ to nine‐year‐old children (N = 97) drew two occluding model cubes and solved several other spatial tasks. Girls more often unfolded the various sides of the cubes into a layout, also called diagrammatic cube drawing (object design detail). In girls, the best predictor for drawing the cubes was Mental Rotation Test (MRT) accuracy. ...
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Shape But Not Color Facilitates Two-Year-Olds’ Search Performance in a Spatial Rotation Task
(2018)
Children younger than 3 years of age often fail to track hidden objects that are rotated together with identical hiding containers, which might be due to relatively complex paradigms. We examined whether 2-year-olds (N = 28) are already able to track spatial rotations (i.e., by 90° and 180°) if the task is facilitated by increasing the visual discriminability of the hiding containers by means of different shapes and different colors. Children performed above chance level in all conditions except for the condition in ...
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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 ...
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Verbal facilitation effects instead of verbal overshadowing in face memory of 4- to 6-year olds
(2015)
Research on eye witness memory in older children and adults revealed that verbally describing unfamiliar faces impairs later recognition of these faces, known as the “verbal overshadowing effect”. The aim of this study was to investigate whether a verbal overshadowing effect occurs in 4- to 6-year olds, too, and whether visualization (i.e., drawing the seen face) might elicit a visual overshadowing effect. Instead of a verbal overshadowing effect, a verbal facilitation effect was revealed with verbal intelligence ...
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Cyclic degradation of Co49Ni21Ga30 high-temperature shape memory alloy - On the roles of dislocation activity and chemical order
(2015)
Conventional shape memory alloys (SMAs), such as binary Ni-Ti, are typically limited to service temperatures below 100 °C. Recent studies on Co-Ni-Ga high temperature (HT) SMAs revealed the potential that these alloys can be used up to temperatures of about 400 °C. Analysis of the cyclic functional properties showed that degradation in these alloys is mainly triggered by intensive dislocation motion. However, data on the cyclic stress-strain response and the mechanisms leading to functional degradation of Co-Ni-Ga ...
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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 ...
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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, ...
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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 ...