Development of a Cu-Sn based brazing system with a low brazing and a high remelting temperature

Objective of the project presented is the development of a joining process for hot working steel components at low brazing temperatures leading to a bond with a much higher remelting temperature. This basically is achieved by the use of a Cu-Sn melt spinning foil combined with a pure Cu foil. During brazing, the Sn content of the foil is decreased by diffusion of Sn into the additional Cu resulting in a homogenious joint with a increased remelting temperature of the filler metal. Within this project specimens were brazed and diffusion annealed in a vacuum furnace at 850 °C varying the processing times (0 - 10 h). The samples prepared were studied metallographically and diffusion profiles of Sn were recorded using EDX line scans. The results are discussed in view of further investigations and envisaged applications.German Ministry of Economic Affairs and EnergyIGF/IGF 18.706 N/DV

Take It to the Curb: Scalable Communication Between Autonomous Cars and Vulnerable Road Users Through Curbstone Displays

Automated driving will require new approaches to the communication between vehicles and vulnerable road users (VRUs) such as pedestrians, e.g., through external human-machine interfaces (eHMIs). However, the majority of eHMI concepts are neither scalable (i.e., take into account complex traffic scenarios with multiple vehicles and VRUs), nor do they optimize traffic flow. Speculating on the upgrade of traffic infrastructure in the automated city, we propose Smart Curbs, a scalable communication concept integrated into the curbstone. Using a combination of immersive and non-immersive prototypes, we evaluated the suitability of our concept for complex urban environments in a user study (N = 18). Comparing the approach to a projection-based eHMI, our findings reveal that Smart Curbs are safer to use, as our participants spent less time on the road when crossing. Based on our findings, we discuss the potential of Smart Curbs to mitigate the scalability problem in AV-pedestrian communication and simultaneously enhance traffic flow

Preparing drivers for planned control transitions in automated cars

In the near future we expect automated driving to be available for specific segments of a journey, e.g., when driving on the highway. At the end of such a route segment, a (planned) control transition from system to driver occurs. While immediate (unpredictable) take-over situations are heavily investigated, there is still a gap in understanding how to present planned take-over requests, especially while drivers might be involved in non-driving-related activities (NDRAs). We investigated the effect of three different visual representations to indicate planned take-over requests (TOR) on usability, comfort, and driving quality. Additionally, we explored the influences of different NDRAs and the device used for this activity. The results of our simulator study (N=24) indicate that (1) upcoming take-over requests should be displayed dynamically, (2) preferred devices depend on the performed task and (3) take-over requests should be presented with auditory, visual, and tactile cues. Based on our findings, we contribute design recommendations to support the development of safe and comfortable planned control transitions

Preparing drivers for planned control transitions in automated cars

In the near future we expect automated driving to be available for specific segments of a journey, e.g., when driving on the highway. At the end of such a route segment, a (planned) control transition from system to driver occurs. While immediate (unpredictable) take-over situations are heavily investigated, there is still a gap in understanding how to present planned take-over requests, especially while drivers might be involved in non-driving-related activities (NDRAs). We investigated the effect of three different visual representations to indicate planned take-over requests (TOR) on usability, comfort, and driving quality. Additionally, we explored the influences of different NDRAs and the device used for this activity. The results of our simulator study (N=24) indicate that (1) upcoming take-over requests should be displayed dynamically, (2) preferred devices depend on the performed task and (3) take-over requests should be presented with auditory, visual, and tactile cues. Based on our findings, we contribute design recommendations to support the development of safe and comfortable planned control transitions

Lure the Drones - Falconry Inspired HDI

International audienceThe following paper proposes a concept regarding Human Drone Interaction (HDI) based on the traditional profession of falconry. For more then 2500 years humans already practice the interaction with flying agents for hunting and caretaking tasks. Based on the metaphor of the falconer we propose the following system which enables gaze control of drones utilizing a wearable eye-tracker. By taking the "looking at the watch"-pose, which is reminiscent of the "falconer luring its bird"-pose, the eye tracker gets implicitly positioned in front of the user's face. A combination of body posture and eye gaze allows for GUI-free interaction in the field and during physically demanding tasks

Survival after pathogen exposure in group-living insects: don't forget the stress of social isolation!

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Entwicklung einer korrosions- und verschleißbeständigen Eisenbasisschicht

Gegenstand der dargestellten Arbeit war die Entwicklung eines neuen Beschichtungswerkstoffs für den Verschleiß- und Korrosionsschutz von Stahlkomponenten insbesondere für Anwendungen in der Ölbohrtechnik. Die Arbeit konzentrierte sich hierbei auf eine kostengünstige Beschichtungslösung für großvolumige Komponenten, mit dem Ziel, in Zukunft die bislang hierfür verwendeten, teuren hochlegierten Stahlgüten beispielsweise für Borgestänge oder Futterrohre gegen kostengünstige Stahlwerkstoffe ersetzen zu können. Für diesen Zweck wurde eine pulverförmige Eisenbasislegierung aus dem System Fe-Cr-Al-B-Si entwickelt, die für thermische Beschichtungsprozesse wie das thermische Spritzen oder das Auftraglöten geeignet ist. Es wurden hiermit Beschichtungsversuche mittels atmosphärischen Plasmaspritzens (APS) und Hochgeschwindigkeitsflammspritzens (HVOF) durchgeführt und die aufgespritzten Schichten zur Verbesserung der Haftfestigkeit in einem Ofenprozess umgeschmolzen und gesintert. Die metallurgischen Schichteigenschaften wurden metallographisch und rasterelektronenmikroskopisch analysiert. Zudem wurden ortsaufgelöste Härtemessungen und elektrochemische Korrosionsmessungen an den Schichten durchgeführt, die erfolgversprechende Erkenntnisse über die zu erwartende Verschleiß- und Korrosionsbeständigkeit des Schichtsystems lieferten

Mechanismen der Oberflächendesoxidation während des Vakuumlötens von Edelstählen

Das Vakuumlöten von korrosions- und hitzebeständigen Edelstählen ist eine wichtige-Fügetechnik, die unter anderem in der Produktion von Abgaskomponenten für Kraftfahrzeuge eingesetzt wird. Die physikalischen und chemischen Vorgänge, die während des Lötprozesses an den Grenzflächen stattfinden, sind kaum untersucht. Mit dem Ziel, aus dem Verständnis dieser Prozesse heraus die Lötbarkeit von Hochleistungsstählen zu verbessern, wird ein Vergleich zwischen einem aluminiumhaltigen ferritischen Edelstahl und einem aluminiumfreien austenitischen Edelstahl gezogen. Anschließend wird ein Ansatz zur Verbesserung der Lötfähigkeit von Edelstählen in silandotiertem Argon-Grobvakuum vorgestellt