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!
A two-atom quantum duet
12.11.2018 | Institute for Basic Science
Improving understanding of how the Solar System is formed
12.11.2018 | Goethe-Universität Frankfurt am Main
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
Physicists at ETH Zurich demonstrate how errors that occur during the manipulation of quantum system can be monitored and corrected on the fly
The field of quantum computation has seen tremendous progress in recent years. Bit by bit, quantum devices start to challenge conventional computers, at least...
Scientists developed specially coated nanometer-sized vehicles that can be actively moved through dense tissue like the vitreous of the eye. So far, the transport of nano-vehicles has only been demonstrated in model systems or biological fluids, but not in real tissue. The work was published in the journal Science Advances and constitutes one step further towards nanorobots becoming minimally-invasive tools for precisely delivering medicine to where it is needed.
Researchers of the “Micro, Nano and Molecular Systems” Lab at the Max Planck Institute for Intelligent Systems in Stuttgart, together with an international...
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