Which design principles unify the diversity of life on earth? To understand how biological designs emerged by natural selection, biomechanics studies organisms by applying engineering science and mechanics. Biomechanics studies life from molecules to ecosystems. Questions range ‘how do cells form tissue’, over ‘what shapes a muscle’ to ‘how do animals fly’ and ‘which mechanical constraints govern body shape and -dynamics when animals increase in size’. Biomechanics is applied not only to extant but also fossil organisms to reconstruct the way of life of extinct plants and animals.
Most biomechanists aim to unravel the building principles of nature by reverse engineering. But they also work in the opposite direction from biomechanical solutions to engineering designs. This field is known as biomimetics, and several examples are discussed in this issue. One famous example is George de Mestral’s invention of Velcro that was inspired by the cockleburs ingenious attachment mechanism. We are only beginning to exploit the rich source of stunning designs found in nature.
How to perform measurements in a hovering animal’s wake: Physical modelling of the vortex wake of the hawkmoth, Manduca sexta” (Tytell, E.D., and Ellington, C.P.)
How difficult is it to estimate forces on the wings of a flying insect or bird by measuring the airflow in its wake? Difficult, but not impossible, according to our study modelling the wake of a flying hawkmoth, and maybe easier on smaller animals. One of the major difficulties in studying animal flight has been that the wings often move too fast to make any useful measurements of the air flow around them. This is a sizeable problem, because insects and some small birds take advantage of a wide array of ‘high lift’ mechanisms that may be useful for future generations of flying machines. Rather than trying to make the difficult measurements around actual moving wings, most researchers have tried to deduce the forces on the wings from the airflow in the wake. While theoretically possible, this type of measurement had a setback in the ‘80s, when two studies on birds measured too little force to keep the animals aloft. Our study examines the feasibility of these measurements by studying the flow behind a highly simplified physical model of a hawkmoth. The trouble, it turns out, is turbulence. Large animals, including all but the smallest birds, produce wakes with substantial turbulence that causes the wake to loose strength rapidly, making it very difficult to back-calculate the forces around the wings. This back-calculation is not impossible, just difficult; but it is probably not feasible in a real experimental setup. Most insects, though, are small enough that their wakes are laminar, with smooth and even flow, which makes the wake strength stay constant for a long time. Our study shows that it is feasible to examine insects’ high lift mechanisms by observing the airflow in the wake behind them because of their laminar wakes.
Cyberkelp: An integrative approach to the modeling of flexible organisms (M. Denny and B. Hale)
Biomechanical models come in a variety of forms: conceptual models, physical models, and mathematical models (both of the sort written down on paper and the sort carried out on computers). There are model structures (such as the muscles that power insect flight muscle the tendons of rats’ tails), model organisms (such as the moth, Manduca sexta), even model systems of organisms (such as the communities that live on wave-swept rocky shores). These different types of models are typically employed separately, but their value often can be enhanced if their insights are combined. In this brief report we explore a particular example of such integration among models, as applied to a flexible marine alga, the giant bull kelp Nereocystis leutkeana. Because of these seaweeds’ large size and wave-swept habitat, it is difficult to make measurements on them directly. But because of their economic and ecological importance, it would be advantageous to understand how they work. A conceptual model (a submerged buoyant ball tethered to the seafloor by a rubbery string) serves as a template for the construction of a mathematical model of this model species of kelp. The validity of this numerical model is then tested in the laboratory using small physical models. The validated mathematical model is then used in conjunction with a computer-controlled testing apparatus to simulate the forces that would be placed on a real, full-size kelp in the ocean. This combination of models (what we call “cyberkelp”) allows us to experiment with a species that would otherwise be beyond our abilities.
Tim Watson | alfa
Cancer diagnosis: no more needles?
25.05.2018 | Christian-Albrechts-Universität zu Kiel
Less is more? Gene switch for healthy aging found
25.05.2018 | Leibniz-Institut für Alternsforschung - Fritz-Lipmann-Institut e.V. (FLI)
The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.
Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...
A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.
The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
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