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
Rutgers scientists discover 'Legos of life'
23.01.2018 | Rutgers University
Researchers identify a protein that keeps metastatic breast cancer cells dormant
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Physicists have developed a technique based on optical microscopy that can be used to create images of atoms on the nanoscale. In particular, the new method allows the imaging of quantum dots in a semiconductor chip. Together with colleagues from the University of Bochum, scientists from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute reported the findings in the journal Nature Photonics.
Microscopes allow us to see structures that are otherwise invisible to the human eye. However, conventional optical microscopes cannot be used to image...
On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.
We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...
What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...
For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.
Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...
At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.
No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...
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