The researchers, led by Ramin Golestanian of the University of Sheffield, coated one side of each polystyrene ball with a thin layer of platinum before dropping them into a solution of hydrogen peroxide and water. This metal catalyzes a reaction in which hydrogen peroxide breaks into oxygen and water. Because the reaction spits out three molecules for every two that it consumes, the polystyrene ball is pushed from the platinum side.
Objects as small as these polystyrene balls naturally wander about randomly, a phenomenon caused by jostling about among vibrating atoms and molecules. This "random walk" movement is called Brownian motion. To account for it, the platinum-coated balls were tested against polystyrene balls with no coating.
Over short distances, they found that the half-coated balls moved in a particular direction although their paths meandered over longer distances. Still, the wanderings of the coated balls were distinct from the Brownian motion of the uncoated balls. Their paths were a random walk with step sizes that depended on the concentration of hydrogen peroxide. The larger the hydrogen peroxide concentration, the larger the step.
Physicists have yet to devise a way to keep the balls heading in a particular direction, but chemical reaction catalysis may prove a useful method for propelling microscopic objects in liquids. - KMDiamonds unlikely in gas giants like Uranus
Physicists at the Universtiet van Amsterdam and the FOM Institute for Atomic and Molecular Physics in the Netherlands performed a numerical analysis showing that at the temperatures and pressures in gas giant planets like Uranus, arrangements of carbon atoms would be much more suitable for creating tiny bits of graphite rather than diamond.
In white dwarfs, on the other hand, the simulation shows that the conditions would cause the carbon atoms to line up in configurations that are much more amenable for diamond crystallization. The conclusion is consistent with the 2004 discovery of a cooling white dwarf star that appears to have a solid diamond core 4000 kilometers across.
Although diamond formation in the atmospheres of gas giants is not strictly impossible, the Dutch physicists say that the odds are exceedingly slim that a diamond could have formed under the conditions that exist in Uranus in the entire lifetime of the universe. - JRMiraculous Mosquito Legs
Like flies, mosquito feet are equipped with hooked claws for clinging to skin. Like geckos, they have hairy pads on their feet that stick to nearly any smooth surface with a velcro-like grip. But it's their ability to walk on water that really makes mosquitoes stand out in the animal kingdom.
Both water striders and mosquitoes rely on superhydrophobic (extremely water repelling) legs to allow them to stand on pond surfaces. Water striders' legs do a pretty good job of it, repelling water well enough to support up to 15 times their body weight. Mosquitoes, however, can easily beat that. Experiments now reveal that they repel water so well that each of a mosquito's six legs could support 23 times the insect's weight. The physicists measured the water repellant ability of mosquito legs by attaching an amputated leg to the end of a needle and recording the force as they pushed it down into a container of water.
The secret to mosquito water walking appears to be feathery scales a few microns across that in turn are covered with nanoscopic ribbing, forming what the physicists have dubbed (in an apparent fit of excessive prefixing) a micronanostructure. So the next time a mosquito lands on your arm, take a moment to ponder its impressive and versatile leg adaptations -- then squish it before it sucks your blood. - JR
James Riordon | EurekAlert!
Black hole spin cranks-up radio volume
15.01.2018 | National Institutes of Natural Sciences
The universe up close
15.01.2018 | Georg-August-Universität Göttingen
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.
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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...
Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.
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The oceans are the largest global heat reservoir. As a result of man-made global warming, the temperature in the global climate system increases; around 90% of...
Scientists at Helmholtz Zentrum München have discovered a mechanism that amplifies the autoimmune reaction in an early stage of pancreatic islet autoimmunity prior to the progression to clinical type 1 diabetes. If the researchers blocked the corresponding molecules, the immune system was significantly less active. The study was conducted under the auspices of the German Center for Diabetes Research (DZD) and was published in the journal ‘Science Translational Medicine’.
Type 1 diabetes is the most common metabolic disease in childhood and adolescence. In this disease, the body's own immune system attacks and destroys the...
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