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Auswahl der Herniennetze nach der “effektiven Porosität” - warum das Gewicht weniger wichtig ist
(2012)
Use of textile structures for reinforcement of pelvic floor structures has to consider mechanical forces to the implant, which are quite different to the tension free conditions of the abdominal wall. Thus, biomechanical analysis of textile devices has to include the impact of strain on stretchability and effective porosity. Prolift® and Prolift + M®, developed for tension free conditions, were tested by measuring stretchability and effective porosity applying mechanical strain. For comparison, we used Dynamesh-PR4®, which was designed for pelvic floor repair to withstand mechanical strain. Prolift® at rest showed moderate porosity with little stretchability but complete loss of effective porosity at strain of 4.9 N/cm. Prolift + M® revealed an increased porosity at rest, but at strain showed high stretchability, with subsequent loss of effective porosity at strain of 2.5 N/cm. Dynamesh PR4® preserved its high porosity even under strain, but as consequence of limited stretchability. Though in tension free conditions Prolift® and Prolift + M® can be considered as large pore class I meshes, application of mechanical strain rapidly lead to collapse of pores. The loss of porosity at mechanical stress can be prevented by constructions with high structural stability. Assessment of porosity under strain was found helpful to define requirements for pelvic floor devices. Clinical studies have to prove whether devices with high porosity as well as high structural stability can improve the patients' outcome.
ε-Fe3N has been investigated by time-of-flight neutron diffraction (temperature range 4.2–618 K) and SQUID magnetometry (2–700 K, B≤5 T). A ferromagnetic spin structure is observed with magnetic moments oriented perpendicular to the c-axis of the hexagonal nuclear structure. The magnetic saturation moment of iron is 2.2 μB at 4.2 K from neutron diffraction and 2.0 μB from magnetic measurements and decreases in a Brillouin-like manner on heating to TC=575 K. Above 450 K an increasing but reversible disorder of the nitrogen partial structure is observed.
The integration of sensors is one of the major tasks in embedded, control and “internet of things” (IoT) applications. For the integration mainly digital interfaces are used, starting from rather simple pulse-width modulation (PWM) interface to more complex interfaces like CAN (Controller Area Network). Even though these interfaces are tethered by definition, a wireless realization is highly welcome in many applications to reduce cable and connector cost, increase the flexibility and realize new emerging applications like wireless control systems. Currently used wireless solutions like Bluetooth, WirelessHART or IO-Link Wireless use dedicated communication standards and corresponding higher protocol layers to realize the wireless communication. Due to the complexity of the communication and the protocol handling, additional latency and jitter are introduced to the data communication that can meet the requirements for many applications. Even though tunnelling of other bus data like CAN data is generally also possible the latency and jitter prevent the tunnelling from being transparent for the bus system. Therefore a new basic technology based on dual-mode radio is used to realize a wireless communication on the physical layer only, enabling a reliable and real-time data transfer. As this system operates on the physical layer it is independent of any higher layers of the OSI (open systems interconnection) model. Hence it can be used for several different communication systems to replace the tethered physical layer. A prototype is developed and tested for real-time wireless PWM, SENT (single-edge nibble transmission) and CAN data transfer with very low latency and jitter.
Wireless CAN
(2018)
In modernen elektronischen und mechatronischen Systemen, z. B. im industriellen oder automobil Bereich, kommunizieren eingebettete Steuergeräte und Sensoren vielfach über Bussysteme wie CAN oder LIN. Die Kommunikation findet in der Regel drahtgebunden statt, so dass der Kabelbaum für die Kommunikation sehr groß werden kann. Daher ist es naheliegend, Leitungen und dazugehörige Stecker, z. B. für nicht-sicherheitskritische Komfortsysteme, einzusparen und diese durch gerichtete Funkstrecken für kurze Entfernungen zu ersetzen. Somit könnten Komponenten wie ECUs oder Sensoren kabel- und steckerlos in ein Bussystem integriert werden. Zudem ist eine einfache galvanische und mechanische Trennung zu erreichen. Funkübertragung wird bei diesen Bussystemen derzeit nicht eingesetzt, da insbesondere die Echtzeitfähigkeit und die Robustheit der vorhandenen Funksysteme nicht den Anforderungen der Anwendungen entspricht. Zudem sind bestehende Funksysteme wie WLAN oder Bluetooth im Vergleich zur konventionellen Verkabelung teuer und es besteht hierbei die Möglichkeit, dass sie ausspioniert werden können und so sensible Daten entwendet werden können. In dieser Arbeit wird eine alternative Realisierung zu den bestehenden Funksystemen vorgestellt, die aus wenigen Komponenten aufzubauen ist. Es ist eine protokolllose, echtzeitfähige Übertragung möglich und somit die transparente Integration in ein Bussystem wie CAN.