BuzzSkyline writes: University of Texas physicists have built the world's smallest radiometer. The minuscule radiometer is only 2 millimeters across and operates on the same principles as the common light-driven toy, which consists of spinning black and white vanes in a partially evacuated bulb. The researchers attached a mirror to their tiny radiometer and used it to rapidly scan a laser beam. Their hope is that they will be able to incorporate the radiometer into catheters to drive scanners that produce medical images of the interiors of blood vessels and organs. The devices would replace micromotors in conventional catheter-based scanners, eliminating the need to run potentially risky electrical currents into the body.
BuzzSkyline writes: Researchers in Belgium have developed devices to harvest the waste heat our bodies throw off in order to convert it to electricity to run devices such as a wristband blood oxygen sensor and an electrocardiogram shirt. As a side benefit, the power sources help cool you down and keep you looking cool, all while running sundry micropower devices. In fact, the researchers mention that the energy harvesting head band works so well that it can get uncomfortably cold. In that case, they say, "This problem is solved in exactly the same way as someone solves it on the body level in cold weather: a headgear should be worn on top of the system to limit the heat flow and make it comfortable." But it would be such a shame to cover up the golden heat-harvesting headband with a hat. The research was published last month in the Journal of Renewable and Sustainable Energy.
BuzzSkyline writes: Physicists have found that there is an ultimate limit to the speed of calculations, regardless of any improvements in technology. According to the researchers who found the computation limit, the bound "poses an absolute law of nature, just like the speed of light." While many experts expect technological limits to kick in eventually, engineers always seems to find ways around such roadblocks. If the physicists are right, though, no technology could ever beat the ultimate limit they've calculated. At the current Moore's Law pace, computational speeds will hit the wall in 75 years. A paper describing the analysis, which relies on thermodynamics, quantum mechanics and information theory, appeared in a recent issue of Physical Review Letters.
BuzzSkyline writes: "Last month, math students published a model of a zombie infestation that explained how the disease might spread. A new physics paper offers help for the more immediate problem — how to avoid being eaten. The paper, which recently appeared in the journal Physical Review E, considers where best to hide when being pursued by zombie-like predatory "random walkers." Although the researchers weren't thinking of zombies when they wrote the paper, the abstract describes the research as focusing on "the survival probability of immobile targets annihilated by a population of random walkers." (Sounds like a zombie movie premise to me.) The bottom line is you're better off the more labyrinth-like your hiding place is. So take a lesson from Dawn of the Dead, and hunker down in the mall, not in a farmhouse (as in Night of the Living Dead)."
BuzzSkyline writes: Ukrainian researchers have managed to take pictures of atoms that reveal structure of the electron clouds surrounding carbon nuclei in unprecedented detail. Although the images offer no surprises (they look much like the sketches of electron orbitals included in high school science texts), this is the first time that anyone has directly imaged atoms at this level, rather than inferring the structure of the orbitals from indirect measurements such as electron or x-ray interferometry.
BuzzSkyline writes: "Improvements in helmets have helped modern soldiers survive bullets and blasts that would have killed them in past wars. But increasing numbers of soldiers are suffering long lasting brain damage from explosions, partly as a result of what appears to be a flaw in helmet designs. Although the blast itself may not accelerate the brain inside a soldier's head enough to cause injury, shockwaves that make it through the space between a helmet and a soldier's head can cause the skull to flex, leading to ripples in the skull that can create damaging pressures in the brain. Simulations that relied on "code originally designed to simulate how a detonated weapon rattles a building or tank" could lead to new helmets that reduce the traumatic brain injuries that many soldiers suffer as a result of improvised explosive devices and other moderate-sized blasts. The research is due to be published in Physical Review Letters, but a preprint is currently available on the Physics ArXiv."
BuzzSkyline writes: "Despite fire codes that require emergency exits be clear of obstacles, some types of obstacles actually speed evacuation. The counterintuitive conclusion resulted from a series of experiments performed at a TV studio in Japan. Researchers from the University of Tokyo asked 50 volunteers to exit the studio through a narrow door. Video tapes of the experiments show that that people made it out quickest when a pole was placed about 30 degrees to one side of the exit. The lead researcher believes an obstacle reduces jamming and friction among people in crowds by decreasing conflicts as the crowd presses toward the exit. A paper describing the researcher is schedule to appear in the journal Physical Review E in September, but a preprint is available on the Physics Arxiv."
BuzzSkyline writes: "Some email rumors and hoaxes spread like wildfire and then peter out quickly. Others spread slowly but keep making the rounds for years. So what's the difference? According to an experiment conducted by researchers at the University Carlos III of Madrid working together with IBM's European e-marketing division, it depends on whether the rumor crosses the gossip tipping point. The experiment, which is being reported in Physical Review Letters, consisted of a marketing campaign that awarded a raffle ticket for a laptop to people who referred friends to a newsletter subscription. The researchers found that as long as the number of hyper-connected users who pass on emails immediately exceeded a critical value (i.e. the tipping point), the campaign message goes viral. Otherwise, the message ends up as a slow moving, long-lasting rumor that is primarily spread by people who let messages sit in their inboxes for a long time before passing them on. The experiment is unusual for this sort of research — most papers dealing with information diffusion in social networks are purely theoretical."
BuzzSkyline writes: "Traffic jams are minimized if a significant fraction of drivers break the rules by doing things like passing on the wrong side or changing lanes too close to an intersection. The insight comes from a cellular automata study published this month in the journal Physical Review E. In effect, people who disregard the rules help to break up the groups that form as rule-followers clump together. The risk of jamming is lower if all people obey the rules than if they all disobey them, according to the analysis, but jamming risk is lowest when about 40 percent of people drive like jerks."
BuzzSkyline writes: "It's possible to produce energy by simply mixing fresh and salty water. Although chemists and physicists have long known about the untapped energy available where fresh water rivers pour into salty oceans, the technology for exploiting the effect has been lacking. An Italian physicist seems to have solved the problem with the experimental demonstration of a "salination cell" that creates power given nothing more than input sources of salty and fresh water. Apparently the renewable, environmentally friendly energy source is comparable to "each river in the world ending at its mouth in a waterfall 225 meters [739 feet] high." A paper describing the technology is due to be published in an upcoming issue of the journal Physical Review Letters."
BuzzSkyline writes: "The same folks who brought us the tsunami invisibility cloak last year have come up with an earthquake invisibility cloak. They show that a platform made of just the right configuration of elastic rings could make a structure invisible to earthquakes by effectively steering a quake around the structure. It doesn't work well for compression waves, but the researchers claim it could hide buildings from the slower-moving, more destructive shear earthquake waves. The research is due to be published soon in the journal Physical Review Letters."
BuzzSkyline writes: "Physics Buzz is reporting on the 7th International Human-Powered Submarine Races, held all last week at Carderock Naval Surface Warfare Center in Maryland. Contestants crawled inside homemade fiberglass submarines to pedal for glory down a 100-meter underwater course. The biennial contest, staged in a 3000-foot-long test pool, draws university and high school students from across the US as well as the UK, Mexico, Canada, and Venezuela. (Florida's Springstead High School and their sub, Sublime, FTW!)"
BuzzSkyline writes: "Physicists have been working to develop metamaterial-based invisibility technology for years, but now a group of researchers in Hong Kong has published a paper in the journal Physical Review Letters that offers even more imaginative applications. According to one of the Phys. Rev. editors, the researchers "describe how a particular object could be optically transformed into another: a spoon may appear to be a cup, or one may see a peephole where there is really a solid wall. Rendering an object invisible then becomes one case out of many possible illusions." Oddly enough, Sirius Black is not listed as one of the authors."
BuzzSkyline writes: "Sure, he's officially the US Energy Secretary now, but Steven Chu still has enough physicist in him to have a paper published in this week's issue of Physical Review Letters. He and his coauthors have developed a new and improved atom interferometer, which could be used to aid aircraft navigation, detect gravitational waves from supernovas and colliding black holes, or perform various other super-sensitive measurements."