A Rebound Effect After Stereotype Threat?

Two studies investigated a potential cognitive mediator for stereotype threat, a phenomenon whereby the mere threat of confirming a negative stereotype results in a performance deficit. It was hypothesized that people attempt to suppress stereotypes in memory during threatening situations, consuming cognitive resources, but that the suppression is released after the threatening situation has ended. This results in a “rebound effect” and a subsequent increase in stereotyped thought. The experiments failed to find a significant stereotype threat effect when examined individually, but when the data from the experiments were aggregated aggregated, a performance deficit was found. However, because of the failure to find a significant performance deficit in any one experiment, the results to not directly bear on any potential rebound effect

A Comparison of Gecko Adhesion on Soft Substrates

Gecko adhesion has been studied for years, and geckos must navigate among a variety of surfaces in their natural environment. Previous work investigating gecko adhesion on soft substrates suggested that geckos cannot stick to soft surfaces, although only one soft material was tested. This study, using tokay geckos (Gekko gecko), explored gecko adhesion on other soft substrates than those previously studied, including natural rubber, neoprene rubber, and nitrile rubber. The study found that geckos can, in fact, adhere to soft surfaces, although they stick to some better than others. To investigate these differences, the tested surfaces were characterized based on their softness and surface chemistry. Interestingly, the surface characterization data was inconclusive about any potential differences between the surfaces that would cause the adhesion variability seen. These results suggest that there are other factors behind variable adhesion forces for the different surfaces other than surface chemistry and softness

Der Modulare Multilevel-Umrichter als dreiphasige Spannungsquelle

Die universelle dreiphasige Spannungsquelle stellt eine galvanisch getrennte Ausgangsspannung mit frei einstellbarer Amplitude und Frequenz sowie bidirektionalem Leistungsfluss dar. Zudem soll diese einen niedrigen Oberschwingungsgehalt, hohe Dynamik und kurze Reaktionszeit der Ausgangsspannung bereitstellen. Anwendbar sind universelle dreiphasige Spannungsquellen beispielsweise zum Testen von elektrischen Betriebsmitteln und zum Prüfen des Verhaltens von Erzeugungseinheiten als Folge von Fehlerfällen im Netz. Ebenfalls denkbar ist der Einsatz in Power Hardware-in-the-Loop-Prüfständen, die zur Nachbildung von elektrischen Netzen und Maschinen dienen. In dieser Arbeit wird ein neues, in der Spannung skalierbares Konzept für eine universelle dreiphasige Spannungsquelle erarbeitet, ausgelegt und aufgebaut. Hierfür wird der Betriebsbereich der Modularen Multilevel-Umrichter erweitert, ein neues Konzept für die galvanische Trennung realisiert sowie ein Verfahren zur aufwandsarmen Erhöhung der Modulationsfrequenz entwickelt. Der Versuchsaufbau wird als Teil eines Power Hardware-in-the-Loop Prüfstands zur Emulation einer hochausgenutzten Synchronmaschine verwendet, um die technische Einsetzbarkeit nachzuweisen

Control Strategy for Modular Multilevel Matrix Converters at High Output Frequencies

This paper presents a new control strategy for Modular Multilevel Matrix converters where the output frequency is higher then the input frequency. In operating points when ω$_{out}$ $\geq \$ ω$_{in}$ the energy pulsation in the converter cells are dominated by the second harmonic of the input frequency. These energy pulsations can be identified and compensated by inducing additional currents. The results are verified by simulation for a laboratory scaled prototype of the Modular Multilevel Matrix Converter