The Airborne Internet is a vision of a large-scale multihop wireless mesh network consisting of commercial passenger aircraft connected via long-range highly directional air-to-air radio links. We propose a geographic load sharing strategy to fully exploit the total air-to-ground capacity available at any given time. When forwarding packets for a given destination, a node considers not one but a set of next-hop candidates and spreads traffic among them based on queue dynamics. In addition, load balancing is performed among Internet Gateways by using a congestion-aware handover strategy. Our simulations using realistic North Atlantic air traffic demonstrate the ability of such a load sharing mechanism to approach the maximum theoretical throughput in the network.

Sensing mechanical tissue deformation in vivo can provide detailed information on organ functionality and tissue states. To bridge the huge mechanical mismatch between conventional electronics and biological tissues, stretchable electronic systems have recently been developed for interfacing tissues in healthcare applications. A major challenge for wireless electronic implants is that they typically require microchips, which adds complexity and may compromise long‐term stability. Here, a chipless wireless strain sensor technology based on a novel soft conductor with high cyclic stability is reported. The composite material consists of gold‐coated titanium dioxide nanowires embedded in a soft silicone elastomer. The implantable strain sensor is based on an resonant circuit which consists of a stretchable plate capacitor and a coil for inductive readout of its resonance frequency. Successful continuous wireless readout during 50% strain cycles is demonstrated. The sensor element has a Young's modulus of 260 kPa, similar to that of the bladder in order to not impair physiological bladder expansion. A proof‐of‐principle measurement on an ex vivo porcine bladder is presented, which shows the feasibility of the presented materials and devices for continuous, wireless strain monitoring of various tissues and organs in vivo.

The 2014 Iquique‐Pisagua Mw 8.1 earthquake ruptured only parts of the 1877 Northern Chile‐Southern Peru seismic gap. Here we present a comprehensive analysis of 152 continuous and campaign Global Positioning System time series that captured more than a decade of interseismic loading prior to the event and 2 years of afterslip. In high spatiotemporal resolution, our data document upper plate response not only at the coseismically affected latitudes but also at the adjacent Loa plate segment to the south. Using a combination of elastic and viscoelastic half‐space models of different stages of the seismic cycle, we found that the highly coupled, former seismic gap contains a narrow low coupling zone at 21°S latitude. Just after the 2014 earthquake, this zone acts as a barrier impeding afterslip to continue southward. Possible reasons for this impediment could involve crustal heterogeneities or coupling discontinuities at the plate interface. After 2 years, afterslip cumulates to a maximum of ~89 cm and becomes negligible. Global Positioning System observations south of the inferred seismotectonic barrier reveal a deformation rate increase in the second year after the event. Our slip models suggest that this could be caused by a downdip coupling increase, perhaps bringing the highly coupled southern Loa segment closer to failure. Taken together, our results reveal (1) the interaction between different areas undergoing stress release and stress buildup in a major seismic gap, (2) constraints for the temporal variation of coupling degree in different stages of the seismic cycle, and (3) the influence of large earthquakes at adjacent segments.

In this work, the quadruple active bridge dc-dc converter (QAB) is proposed to be used as a building block to implement the dc-dc stage of a Smart Transformer (ST). Different configurations (symmetrical, asymmetrical, rated for voltage/power) for this converter are considered for investigation. Four different architectures of ST, including one based on the Dual Active Bridge (DAB) converter as a benchmark and three based on the QAB converter, are presented and compared in terms of cost, efficiency, reliability and implementation complexity. As an additional contribution, different semiconductors technologies (silicon IGBT and silicon carbide MOSFETs) are evaluated in order to verify their impact on ST application. The design for each architecture is described and the results are compared. In order to validate the theoretical analysis developed in the paper, a 20 kW prototype was built and experimented.Index Terms-Dc-dc converter, multiple active bridge converter, multiwinding transformer, smart Transformer.

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Kurzfassung Der grundlegende Ansatz, den Verzug von Bauteilen als eine Systemeigenschaft aufzufassen, setzt sich im wissenschaftlichen, aber auch im industriellen Kontext immer mehr durch. Der im Jahr 2001 eingerichtete Sonderforschungsbereich „Distortion Engineering – Verzugsbeherrschung in der Fertigung“ hat diesen Ansatz aufgegriffen und beschäftigt sich mit der Bestimmung signifikanter Einflussgrößen und Wechselwirkungen über die gesamte Fertigungskette von ausgewählten Bauteilen, um die wesentlichen Mechanismen der Verzugsentstehung zu identifizieren. In diesem Zusammenhang kommt der bauteilspezifischen Beschreibung des Verzuges für eine erfolgreiche Lösung der Verzugsproblematik eine wesentliche Bedeutung zu. Im Bereich der Wälzlagertechnik ist eine entscheidende Kenngröße die Rundheitsabweichung der Laufbahnen. Zur Analyse der Verzüge ist diese Größe allerdings nur bedingt geeignet, da sie keine Informationen zur Form des Verzuges liefert. Deshalb wird in der Literatur zur Verzugsbeschreibung die Fourieranalyse eingesetzt, die es ermöglicht, die Rundheitsabweichungen in ihre jeweilige Erscheinungsform, wie z.B. Ovalität oder Dreieckigkeit, aufzuschlüsseln. Zudem ist es über diese Analyse möglich, den Verzug zusätzlich zur Angabe eines Betrages noch mit einer Richtung in den verschiedenen Erscheinungsformen zu beschreiben. In diesem Beitrag sollen die Möglichkeiten der Fourieranalyse zur Verzugsbeschreibung am Beispiel eines Kegelrollenlageraußenringes vorgestellt werden. Neben den grundsätzlichen Aspekten der Fourieranalyse wird eine neue Darstellungsform zur Verzugsanalyse in der komplexen Zahlenebene eingeführt, die sowohl den Betrag als auch die Richtung des Verzuges veranschaulicht.