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Ameisen der Gattung Cataglyphis sind in der Lage, auf Basis propriozeptiver Signale zu navigieren. Dabei werden Odometrie und der Neigungswinkel des Untergrunds über die Beinbewegung ermittelt. Das System ist robust und funktioniert mit geringem rechnerischen Aufwand. Dadurch eignet es sich als Vorbild für die Navigation von Laufrobotern in schwierigem Gelände. Ziel ist die Entwicklung eines breit anwendbaren generischen Systems, das über ein bionisch inspiriertes Odometer verfügt. Im Speziellen wird untersucht, ob die charakterisierende Größe in der Neigungsbestimmung die in den Beinen wirkenden Kräfte sind. Die Positionierung der Kraftsensoren im Ameisenbein legt eine weitere Vereinfachung auf die in den Gelenken auftretenden Drehmomente nahe. Die Implementierung des Odometers wird in einer Simulation sowie an einer robotischen Einzelbeinplattform validiert. Vorteile dieses Systems sind die kostengünstige und kompakte Implementierung, die im besten Fall keine zusätzlichen Sensoren benötigt und eine Positionsbestimmung in Echtzeit ohne externe Infrastruktur ermöglicht
Adhesive organs enable insects to reversibly adhere to substrates even during rapid locomotion. In this process a very fast but reliable change of adhesion and detachment is realised. The stick insect Carausius morosus detaches its adhesive organs by peeling them off the substrate, meaning little areas of the adhesive organs are detached one after another. For such a detachment mechanism low pulling forces are needed. A detachment mechanism as peeling seems also for artificial adhesion devices to be the easiest and the most effortless mechanism for detachment. However, artificial adhesion devices mostly exhibit a solid backing layer preventing effortless peeling. To lift up and detach a small area at the corner of an adhesion device the backing layer has to be tilted, resulting in a deformation of the whole adhesion device, which requires high forces. Subdividing the backing layer into small subunits allows a detachment of a small area at the corner of the adhesion device without deforming the rest of the adhesion device. Thereby, less force is needed to initiate and to complete detachment. To realise an easy detachment of artificial adhesion devices we constructed a holder, which gradually detaches an adhesion device from two sides off the substrate. During normal loading the subunits of the holder interlock with each other so that the pulling force is equally distributed over the whole contact area of the adhesion device ensuring maximal adhesion force. In addition, the holder can be used to increase adhesion during application of the adhesion device. When brought into contact with the substrate with lifted sides, which are lowered subsequently, air trapping is prevented and hence the area of contact can be maximised.
Die Anwendung des "FullControll GCode Designer" vereinfacht den 3D-Druckprozess, indem er die 3D-Modellierung und den Einsatz eines Slicer-Programms überspringt und stattdessen direkt den G-Code erstellt. Die vorgefertigte Excel-Anwendung ermöglicht es, Objekte durch Angabe der Start- und Zielkoordinaten effizient Linie für Linie mit minimalem Eingabeaufwand zu programmieren, wobei verschiedene Druckparameter angepasst werden können, um unterschiedliche Effekte zu erzielen. In diesem Werk werden die Möglichkeiten und Grenzen des Designers erarbeitet.
Earwig wings are highly foldable structures that lack internal muscles. The behaviour and shape changes of the wings during flight are yet unknown. We assume that they meet a great structural challenge to control the occurring deformations and prevent the wing from collapsing. At the folding structures especially, the wing could easily yield to the pressure. Detailed microscopy studies reveal adaptions in the structure and material which are not relevant for folding purposes. The wing is parted into two structurally different areas with, for example, a different trend or stiffness of the wing veins. The storage of stiff or more flexible material shows critical areas which undergo great changes or stress during flight. We verified this with high-speed video recordings. These reveal the extent of the occurring deformations and their locations, and support our assumptions. The video recordings reveal a dynamical change of a concave flexion line. In the static unfolded state, this flexion line blocks a folding line, so that the wing stays unfolded. However, during flight it extends and blocks a second critical folding line and prevents the wing from collapsing. With these results, more insight in passive wing control, especially within high foldable structures, is gained.
The conventional quantitative method for the analysis of inorganic elements in polymer matrices is a complex and time consuming process that presents a significant risk for error. Typically, polymers are digested in a microwave oven or other devices under high temperature and pressure for several hours while employing different mixtures of high purity acids. In many cases, particularly when high concentrations of doped elements are present, the digestion is often incomplete and therefore the reproducibility depends strongly on the type of polymer and additives used. A promising alternative technology that allows for the direct analysis of these polymers without digestion is laser ablation ICP-MS. Due to a lack of available reference materials and the presence of matrix dependent effects, a precise calibration cannot be obtained. In order to compensate for the matrix dependent effects the use of internal standardization is necessary. In this study the correlation between the carbon released during the ablation process and the 13C signal detected by ICP-MS and its use as an internal standard are investigated. For this purpose, twenty-one virgin polymer materials are ablated; the released carbon is determined and correlated with the corresponding integrated 13C signal. The correlation resulted in a direct relationship between the ablated carbon and 13C signal demonstrating the potential ability to neglect at least some of the matrix dependent and transport effects which occur during the laser ablation of virgin polymers.
We investigated the formation of Artemia franciscana swarms of freshly hatched instar I nauplii larvae. Nauplii were released into light gradients but then interrupted by light-direction changes, small obstacles, or long barriers. All experiments were carried out horizontally. Each experiment used independent replicates. Freshly produced Artemia broods were harvested from independent incubators thus providing true replicate cohorts of Artemia subjected as replicates to the experimental treatments.
We discovered that Artemia nauplii swarms can: 1. repeatedly react to non-obstructed light gradients that undergo repeated direction-changes and do so in a consistent way, 2. find their way to a light source within maze-like arrangements made from small transparent obstacles, 3. move as a swarm around extended transparent barriers, following a light gradient. This paper focuses on the recognition of whole-swarm behaviors, the description thereof and the recognition of differences in whole-swarm movements comparing non-obstructed swarming with swarms encountering obstacles. Investigations of the within-swarm behaviors of individual Artemia nauplii and their interactions with neighboring nauplii are in progress, e.g. in order to discover the underlying swarming algorithms and differences
thereof comparing non-obstructed vs. obstructed pathways.
Mikrostrukturen auf Oberflächen bestimmen häufig deren physikalische Eigenschaften. Die üblichen Methoden zur Herstellung von mikrostrukturierten Oberflächen wie Fotolithografie sind aber teuer und aufwändig. Daher wird schon lange die schnelle und günstige Methode der Abformung genutzt, um Gegenstände mit Mikrostrukturen herzustellen
[1,2]. Zur Nutzung als Positiv für die Abformung können Oberflächen zum Beispiel mit Fotolithografie hergestellt werden, oder es können mikrostrukturierte Objekte aus der Natur verwenden werden. Mittels Fotolithografie können aber keine gewölbten Oberflächen mit Mikrostrukturen versehen werden und mikrostrukturierte Oberflächen aus der Natur sind meist eher klein. In dieser Arbeit wurde daher nach sehr kleinen mikrostrukturierten Objekten gesucht, die nebeneinander auf eine (auch gewölbte) Oberfläche aufgebracht werden können, um diese anschließend abzuformen. Die besten Resultate ergaben mit Bärlappsporen beschichtete Oberflächen als Positive. Replikate dieser Oberflächen zeigen einen um 30° höheren Kontaktwinkel als das unstrukturierte Material.

