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Ventilanordnung und Verfahren zum Kühlen eines Wärmetauschers eines Fahrzeugs [Offenlegungsschrift]
(2023)
Die Erfindung betrifft eine Ventilanordnung umfassend wenigstens ein durch Gas, insbesondere Luft, durchströmbares Ventilelement (1, 1') mit einer Öffnung, wobei der Öffnung ein Dichtelement zugeordnet ist, mit dem die Öffnung verschließbar und/oder öffenbar ist, wobei das Dichtelement durch einen Dichtflächenbereich eines Plattenelements ausgebildet ist, vorzugsweise eines in zumindest einem möglichen Betriebszustand planen Plattenelements ausgebildet ist, wobei das Dichtelement der Öffnung des wenigstens einen Ventilelements gegenüberliegt und der das Dichtelement bildende Dichtflächenbereich des Plattenelements mittels wenigstens eines Spiralarmes mit einem Randflächenbereich des Plattenelements einstückig und relativ zum Randflächenbereich beweglich verbunden ist und der wenigstens eine Spiralarm von wenigstens einer um den Dichtflächenbereich verlaufenden spiralförmigen und durch Gas durchströmbare Ausnehmung in dem Plattenelement zumindest bereichsweise umgeben ist. Die Erfindung betrifft auch ein Verfahren zum Kühlen eines Wärmetauschers in
einem Fahrzeug.
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.
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.
Flying insects employ elegant optical-flow-based strategies to solve complex tasks such as landing or obstacle avoidance. Roboticists have mimicked these strategies on flying robots with only limited success, because optical flow (1) cannot disentangle distance from velocity and (2) is less informative in the highly important flight direction. Here, we propose a solution to these fundamental shortcomings by having robots learn to estimate distances to objects by their visual appearance. The learning process obtains supervised targets from a stability-based distance estimation approach. We have successfully implemented the process on a small flying robot. For the task of landing, it results in faster, smooth landings. For the task of obstacle avoidance, it results in higher success rates at higher flight speeds. Our results yield improved robotic visual navigation capabilities and lead to a novel hypothesis on insect intelligence: behaviours that were described as optical-flow-based and hardwired actually benefit from learning processes.
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.
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.
BACKGROUND: In cartilage repair, scaffold-assisted single-step techniques are used to improve the cartilage regeneration. Nevertheless, the fixation of cartilage implants represents a challenge in orthopaedics, particularly in the moist conditions that pertain during arthroscopic surgery. Within the animal kingdom a broad range of species has developed working solutions to intermittent adhesion under challenging conditions. Using a top-down approach we identified promising mechanisms for biomimetic transfer OBJECTIVE: The tree-frog adhesive system served as a test case to analyze the adhesion capacity of a polyglycolic acid (PGA) scaffold with and without a structural modification in a bovine articular cartilage defect model. METHODS: To this end, PGA implants were modified with a simplified foot-pad structure and evaluated on femoral articular bovine cartilage lesions. Non-structured PGA scaffolds were used as control. Both implants were pressed on 20 mm × 20 mm full-thickness femoral cartilage defects using a dynamometer. RESULTS: The structured scaffolds showed a higher adhesion capacity on the cartilage defect than the non-structured original scaffolds. CONCLUSIONS: The results suggest that the adhesion ability can be increased by means of biomimetic structured surfaces without the need of additional chemical treatment and thus significantly facilitate primary fixation procedures.
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
Desert ants Cataglyphis spec. monitor inclination and distance covered through force-based sensing in their legs. To transfer this mechanism to legged robots, artificial neural networks are used to determine the inclination angle of an experimental ramp from the motor data of the legs of a commercial hexapod walking robot. It is possible to determine the inclination angle of the ramp based on the motor data of the robot legs read out during a run. The result is independent of the weight and orientation of the robot on the ramp and hence robust enough to serve as an independent odometer.