Marc Thielen

The production industry is challenged to become more flexible and efficient while coping with a variety of disruptive events, such as natural disasters, infrastructure blockages, or economic crises. From the individual station on a production line to the global supply chain, everything is connected, making regulation and control a complex task. Biological molecular processes, such as the metabolism of living organisms or the cell cycle, are also extremely complex processes that can be compared to industrial production processes, both of which involve a series of intermediate steps and products. Thanks to (self‐)regulatory mechanisms that have evolved over time, these biological mechanisms are very efficient and robust in the face of perturbations. This article proposes an explanatory representation of these complex processes, considering both biological and technical aspects. The aim is to facilitate biomimetic transfer of biological regulation mechanisms into the technical domain. It presents concepts for biomimetic regulation of production lines and sourcing strategies and introduces a workflow for generating digital twins. This workflow is inspired by the cell cycle checkpoints, which ensure that only perfect copies of DNA are passed on during cell replication. By leveraging this understanding, the production industry can potentially improve its own processes and efficiency.

Tendrils of climbing plants coil along their length, thus forming a striking helical spring and generating tensional forces. It is found that, for tendrils of the passion flower Passiflora caerulea, the generated force lies in the range of 6–140 mN, which is sufficient to lash the plant tightly to its substrate. Further, it is revealed that the generated force strongly correlates with the water status of the plant. Based on a combination of in situ force measurements with anatomical investigations and dehydration‐rehydration experiments on both entire tendril segments and isolated lignified tissues, a two‐phasic mechanism for spring formation is proposed. First, during the free coiling phase, the center of the tendril begins to lignify unilaterally. At this stage, both the generated tension and the stability of the form of the spring still depend on turgor pressure. The unilateral contraction of a bilayer as being the possible driving force for the tendril coiling motion is discussed. Second, in a stabilization phase, the entire center of the coiled tendril lignifies, stiffening the spring and securing its function irrespective of its hydration status.

Extrusion-based 4D-printing, which is an emerging field within additive manufacturing, has enabled the technical transfer of bioinspired self-shaping mechanisms by emulating the functional morphology of motile plant structures (e.g., leaves, petals, capsules). However, restricted by the layer-by-layer extrusion process, much of the resulting works are simplified abstractions of the pinecone scale’s bilayer structure. This paper presents a new method of 4D-printing by rotating the printed axis of the bilayers, which enables the design and fabrication of self-shaping monomaterial systems in cross sections. This research introduces a computational workflow for programming, simulating, and 4D-printing differentiated cross sections with multilayered mechanical properties. Taking inspiration from the large-flowered butterwort (Pinguicula grandiflora), which shows the formation of depressions on its trap leaves upon contact with prey, we investigate the depression formation of bioinspired 4D-printed test structures by varying each depth layer. Cross-sectional 4D-printing expands the design space of bioinspired bilayer mechanisms beyond the XY plane, allows more control in tuning their self-shaping properties, and paves the way toward large-scale 4D-printed structures with high-resolution programmability.

Motile organs have evolved in climbing plants enabling them to find a support and, after secure attachment, to reach for sunlight without investing in a self‐supporting stem. Searching movements, the twining of stems, and the coiling of tendrils are involved in successful plant attachment. Such coiling movements have great potential in robotic applications, especially if they are reversible. Here, the underlying mechanism of tendril movement based on contractile fibers is reported, as illustrated by a function–morphological analysis of tendrils in several liana species and the encoding of such a principle in a core–shell multimaterial fiber (MMF) system. MMFs are composed of a shape‐memory core fiber (SMCF) and an elastic shell. The shape‐memory effect of the core fibers enables the implementation of strain mismatch in the MMF by physical means and provides thermally controlled reversible motion. The produced MMFs show coiling and/or uncoiling behavior, with a high reversible actuation magnitude of ≈400%, which is almost 20 times higher compared with similar stimuli for sensitive soft actuators. The movements in these MMFs rely on the crystallization/melting behavior of oriented macromolecules of SMCF.

Tendrils of climbing plants coil along their length and thus form a striking helical spring and generate tensional forces. We have found that, for tendrils of the passion flower Passiflora caerulea , the generated force lies in the range of 6-140 mN, which is sufficient to lash the plant tightly to its substrate. Further, we revealed that the generated force strongly correlates with the water status of the plant. By combining force measurements with anatomical investigations and dehydration-rehydration experiments on both entire tendril segments and isolated lignified tissues, we are able to propose a two-phasic principle of spring formation: First, during the free coiling phase, the tendril coiling is based on the active contraction of a fiber ribbon in interaction with the surrounding parenchyma as resistance layer. Second, in a stabilization phase, the entire center of the coiled tendril lignifies, stiffening the spring and securing its function independent of hydration status.

Because plants are considered immobile, they remain underrepresented as concept generators for soft robots and soft machines. However, plants show a great variety of movements exclusively based on elastic deformation of regions within their moving organs. The absence of gliding parts, as found in the joints of vertebrates and insects, prevents stress concentration and attrition. Since plants have no central control unit (brain), stimulus-sensing, decision-making and reaction usually take place noncentrally in the hierarchically structured materials systems of the moving organs, in what can be regarded as an example of physical intelligence. These characteristics make plants interesting models for a new group of soft robots and soft machines that differ fundamentally from those inspired by animals. The potential of such plant-inspired soft robots and machines is shown in six examples and is illustrated by examples applied in architecture and medicine. Graphical

Im Lichte des Ausbaus der beruflichen Orientierung an Schulen und sozialer Ungleichheiten am Zugang zur beruflichen Bildung befasst sich der Beitrag mit der Gestaltung von Berufsorientierung an Einzelschulen. Hierzu wird das heuristische Konzept der Übergangskultur diskutiert, das theoretische Prämissen der reflexiven Übergangsforschung der Erziehungswissenschaft mit der Schulkulturforschung verknüpft und unterschiedliche Modi der Gestaltung von Übergängen aus der Sekundarstufe I analysierbar macht. Dies konkretisiert der Beitrag an einer qualitativen Mehrebenenanalyse, mittels derer exemplarisch die Übergangskulturen von zwei nichtgymnasialen Sekundarschulen sowie die mit ihnen einhergehenden Differenz- und Ungleichheitsdynamiken rekonstruiert und kontrastiert werden. Die Befunde verweisen auf die hohe Relevanz einzelschulischer Kontexte, die in den Debatten zur Reproduktion von sozialer Ungleichheit in der Berufsorientierung bislang erst wenig Aufmerksamkeit erfährt.

The development of enhanced processes for filtration is one solution for stopping the increasing freshwater and sea pollution caused by microplastic and microfibers. Major contributors to micro-X pollution are domestic devices such as washing machines, which also hold a high technical potential for separating problematic soils from waste water during cleaning cycles. The focus of the present paper are the biomimetic development of a novel concept for filtration and removal of particles such as microfibers in conventional washing machines. To this goal, a TRIZ analysis yielded viable solutions for the major key issues. In a next step, measurements were made with various filters with and without ribbed structures. The results are promising for the incorporation in a filter concept that is easy to operate and cost-effective.

This study analyzes the impact behavior of lemon peel (Citrus × limon) and investigates its functional morphology compared with the anatomy of pomelo peel (Citrusmaxima). Both fruit peels consist mainly of parenchyma structured by a density gradient. In order to characterize the lemon peel, both energy dissipation and transmitted force are determined by conducting drop weight tests at different impact strengths (0.15–0.74 J). Fresh and freeze-dried samples were used to investigate the influence on the mechanics of peel tissue’s water content. The samples of lemon peel dissipate significantly more kinetic energy in the freeze-dried state than in the fresh state. Fresh lemon samples experience a higher impulse than freeze-dried samples at the same momentum. Drop weight tests results show that fresh lemon samples have a significantly longer impact duration and lower transmitted force than freeze-dried samples. With higher impact energy (0.74 J) the impact behavior becomes more plastic, and a greater fraction of the kinetic energy is dissipated. Lemon peel has pronounced energy dissipation properties, even though the peel is relatively thin and lemon fruits are comparably light. The cell arrangement of citrus peel tissue can serve as a model for bio-inspired, functional graded materials in technical foams with high energy dissipation.