Vorentwurf eines Systems zur Detektion von atmosphärischem Eis auf Grundlage der Erstarrungswärme

In dieser Arbeit wird ein neues Konzept für die Detektion eines Eisansatzes während des Fluges vorgestellt. Um auch unter Vereisungsbedingungen die notwendige Flugsicherheit zu gewährleis-ten und die aktuelle Flugroute beizubehalten, sind zuverlässige Eisdetektions- sowie Enteisungssysteme notwendig. Das Eiserkennungssystem basiert auf der, bei der Erstarrung von Tropfen frei werdenden, Erstar-rungswärme. Die Sensortemperatur liegt stets unterhalb der Umgebungstemperatur, wobei die benötigte Kälteleistung von einem geregelten Peltier-Element erbracht wird. Als Regler und Soft-ware-Hardware-Schnittstelle fungiert ein sogenannter TEC-Controller. Dazu werden zwei mögliche Ansätze untersucht. Zum einen wird eine konstante Temperaturdifferenz zur Umgebung von -5 K und zum anderen eine konstante elektrische Leistung vorgegeben. Es wird gezeigt, dass durch eine Änderung der elektrischen Leistung bzw. der Sensortemperatur, ein Eisansatz detektiert werden kann. Zusätzlich ist es möglich qualitativ die Eiswachstumsrate durch den gemessenen Temperaturgradienten des Sensors bestimmen zu können. Auf Grundlage von numerischen Simulationen in ANSYS Workbench und thermodynamischen Zusammenhängen, wurde das System in CAD-CATIA ausgelegt und dimensioniert. Ein verein-fachter theoretischer Ansatz zur Beschreibung des zusätzlich eingebrachten Wärmestroms bedingt durch den Eisansatz wird detailliert dargestellt. Zusätzlich wurde ein Prototyp zur Integration in der Flügelvorderkante entworfen und im Eiswindkanal des IAF in Braunschweig unter ver-schiedenen Randbedingungen getestet. Die Vor- und Nachteile des Systems werden schließlich unter den Gesichtspunkten der Zuverläs-sigkeit, Wartbarkeit, Wirtschaftlichkeit und Umsetzbarkeit betrachtet

Energy-efficient coding with discrete stochastic events

We investigate the energy efficiency of signaling mechanisms that transfer information by means of discrete stochastic events, such as the opening or closing of an ion channel. Using a simple model for the generation of graded electrical signals by sodium and potassium channels, we find optimum numbers of channels that maximize energy efficiency. The optima depend on several factors: the relative magnitudes of the signaling cost (current flow through channels), the fixed cost of maintaining the system, the reliability of the input, additional sources of noise, and the relative costs of upstream and downstream mechanisms. We also analyze how the statistics of input signals influence energy efficiency. We find that energy-efficient signal ensembles favor a bimodal distribution of channel activations and contain only a very small fraction of large inputs when energy is scarce. We conclude that when energy use is a significant constraint, trade-offs between information transfer and energy can strongly influence the number of signaling molecules and synapses used by neurons and the manner in which these mechanisms represent information

Fast Object Learning and Dual-arm Coordination for Cluttered Stowing, Picking, and Packing

Robotic picking from cluttered bins is a demanding task, for which Amazon Robotics holds challenges. The 2017 Amazon Robotics Challenge (ARC) required stowing items into a storage system, picking specific items, and packing them into boxes. In this paper, we describe the entry of team NimbRo Picking. Our deep object perception pipeline can be quickly and efficiently adapted to new items using a custom turntable capture system and transfer learning. It produces high-quality item segments, on which grasp poses are found. A planning component coordinates manipulation actions between two robot arms, minimizing execution time. The system has been demonstrated successfully at ARC, where our team reached second places in both the picking task and the final stow-and-pick task. We also evaluate individual components.Comment: In: Proceedings of the International Conference on Robotics and Automation (ICRA) 201

VANTED: A system for advanced data analysis and visualization in the context of biological networks

BACKGROUND: Recent advances with high-throughput methods in life-science research have increased the need for automatized data analysis and visual exploration techniques. Sophisticated bioinformatics tools are essential to deduct biologically meaningful interpretations from the large amount of experimental data, and help to understand biological processes. RESULTS: We present VANTED, a tool for the visualization and analysis of networks with related experimental data. Data from large-scale biochemical experiments is uploaded into the software via a Microsoft Excel-based form. Then it can be mapped on a network that is either drawn with the tool itself, downloaded from the KEGG Pathway database, or imported using standard network exchange formats. Transcript, enzyme, and metabolite data can be presented in the context of their underlying networks, e. g. metabolic pathways or classification hierarchies. Visualization and navigation methods support the visual exploration of the data-enriched networks. Statistical methods allow analysis and comparison of multiple data sets such as different developmental stages or genetically different lines. Correlation networks can be automatically generated from the data and substances can be clustered according to similar behavior over time. As examples, metabolite profiling and enzyme activity data sets have been visualized in different metabolic maps, correlation networks have been generated and similar time patterns detected. Some relationships between different metabolites were discovered which are in close accordance with the literature. CONCLUSION: VANTED greatly helps researchers in the analysis and interpretation of biochemical data, and thus is a useful tool for modern biological research. VANTED as a Java Web Start Application including a user guide and example data sets is available free of charge at

Mac John Leuthe - in Wien weltbekannt

Max Johann Leuthe (1879 – 1945) war einer der ersten Wiener, die in der Anfangszeit des Wiener Fußballs dem neuen englischen Ballsport nachgingen. Nach seiner aktiven Karriere als Spieler sollte der mittlerweile zu „Mac John“ gewandelte Leuthe die Mediatisierung des Sportes mitgestalten. Als Journalist und Karikaturist half er den Fußballsport gesellschaftsfähig zu machen. Obendrein schien Max Leuthe für Weltoffenheit zu stehen und pflegte gerne seine Kontakte zur jüdischen Szene Wiens bzw. zu seinen englischen Freunden. All diese Stationen machten ihn zu einer bekannten Persönlichkeit in Wien. Stellt sich die Frage, warum heute nicht mehr an diesen Fußballpionier erinnert wird? Welche Geschichten gibt es zu Mac John Leuthe, wie wird mit seiner Person umgegangen? Anhand von Quellenanalysen, der Aufarbeitung seines Nachlasses und qualitativer Interviews soll versucht werden diese ersten Fragen zu beantworten. Zusätzlich soll eine ausführliche Selbstreflektion den persönlichen Zugang transparent machen und Probleme, die im Forschungsprozess entstanden sind, aufzeigen

Tribological mechanisms of slurry abrasive wear

Abrasive wear mechanisms—including two-body and three-body abrasion—dominate the performance and lifespan of tribological systems in many engineering fields, even of those operating in lubricated conditions. Bearing steel (100Cr6) pins and discs in a flat-on-flat contact were utilized in experiments together with 5 and 13 µm Al$_{2}$O$_{3}$-based slurries as interfacial media to shed light on the acting mechanisms. The results indicate that a speed-induced hydrodynamic effect occurred and significantly altered the systems’ frictional behavior in tests that were performed using the 5 µm slurry. Further experiments revealed that a speed-dependent hydrodynamic effect can lead to a 14% increase in film thickness and a decrease in friction of around 2/3, accompanied by a transition from two-body abrasion to three-body abrasion and a change in wear mechanism from microcutting and microploughing to fatigue wear. Surprisingly, no correlation could be found between the total amount of wear and the operating state of the system during the experiment; however, the wear distribution over pin and disc was observed to change significantly. This paper studies the influence of the hydrodynamic effect on the tribological mechanism of lubricated abrasive wear and also highlights the importance to not only consider a tribological systems’ global amount of wear

Temporally Resolved Intensity Contouring (TRIC) for characterization of the absolute spatio-temporal intensity distribution of a relativistic, femtosecond laser pulse

Today's high-power laser systems are capable of reaching photon intensities up to $10^{22}$ W/cm^2, generating plasmas when interacting with material. The high intensity and ultrashort laser pulse duration (fs) make direct observation of plasma dynamics a challenging task. In the field of laser-plasma physics and especially for the acceleration of ions, the spatio-temporal intensity distribution is one of the most critical aspects. We describe a novel method based on a single-shot (i.e. single laser pulse) chirped probing scheme, taking nine sequential frames at framerates up to THz. This technique, to which we refer as temporally resolved intensity contouring (TRIC) enables single-shot measurement of laser-plasma dynamics. Using TRIC, we demonstrate the reconstruction of the complete spatio-temporal intensity distribution of a high-power laser pulse in the focal plane at full pulse energy with sub picosecond resolution.Comment: Daniel Haffa, Jianhui Bin and Martin Speicher are corresponding author