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!
Astronomers find unexpected, dust-obscured star formation in distant galaxy
24.03.2017 | University of Massachusetts at Amherst
Gravitational wave kicks monster black hole out of galactic core
24.03.2017 | NASA/Goddard Space Flight Center
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
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24.03.2017 | Physics and Astronomy