mercurial
MyBB Legend
1 Super-vision
Who could ever pass up the chance to try on a pair of real X-ray specs? You may not always like what comes into view, but endowed with Superman-like vision, you would be able to see through solid walls, peer in at your neighbours or keep a watchful eye on your kids upstairs. Unfortunately, they still don't exist, despite what those ads at the back of children's comics suggest. Yet there are some technological tricks that can give you the next best thing.
Unlike visible light, radio waves can pass through solid materials. In 2006, engineers at Cambridge Consultants in the UK announced they had built a briefcase-sized system called the Prism 200 which can detect people through a brick wall by firing off pulses of ultrawide-band radar and listening for returning echoes.
According to the company, these pulses can pass through building materials over 40 centimetres thick, and spot activity over a range of up to 15 metres. The device could be used to track people in hostage situations, the company suggests, but it has a crucial weakness. To avoid being blinded by walls and other fixed structures, it is designed to only register objects that generate rapidly varying echoes. In other words, it can only detect people when they move.
Even human statues would be hard pressed to avoid detection by Erwin Biebl's radar sensor, however. Biebl's team at the Technical University of Munich in Germany has built a device that can pick up tiny motions like breathing, or even a beating heart, through a closed door.
His team found that radio waves at between 433 megahertz and 24 gigahertz can pass through skin and bone but are partly reflected by the fatty layer surrounding muscles such as the heart. The team has exploited this by using the Doppler effect to pick up sub-centimetre changes in movement caused by a beating heart or the motion of the lungs.
2 Disappearing act
Few dreams have flipped from science fiction to fact as quickly as "invisibility cloaks". The first, which worked only for microwaves, was unveiled in 2006. Since then the field has been inundated with attempts to make cloaks to rival Harry Potter's.
Cloaking makes an object disappear by steering electromagnetic waves around it - as if the waves had simply passed through. So far, the only way to do this is with "metamaterials", which are made of electronic components designed to interact with light and direct it in a controllable fashion. The goal is to create a cloak that works for a broad spectrum of visible frequencies. Making these components isn't easy. They have to be tiny - smaller than the wavelength of light they are designed to interact with.
Last year, a group at the University of California, Berkeley, constructed a material that was able to bend - rather than reflect - visible light backwards for the first time. Ulf Leonhardt at the University of St Andrews, UK, has shown how metamaterials could work over a range of frequencies.
Even more mind-boggling, a team from The Hong Kong University of Science and Technology in China has worked out how to cloak objects at a distance. They suggest using "complementary materials" which have optical properties that cancel each other out. A wave polarised on a single plane passing through one material will become distorted, but this distortion is cancelled out as the wave passes through the complementary material, making it look as if neither material is there.
3 Hands-free healing
Modern cellphones may do more than a Star Trek "communicator" can, but Doctor "Bones" McCoy's portable medical scanner, which revealed internal injuries in an instant, is taking longer to appear in the real world. When it does, it may go a step further: engineers are developing a portable scanner to not only spot internal injuries like torn arteries, but also heal them in a flash.
The secret of this device is high-frequency sound waves. Medics already use these ultrasound beams to examine babies in the womb. But turn up the intensity and focus the beam into a spot and it can generate enough heat to cook tissue.
Lawrence Crum at the University of Washington in Seattle has shown that high-intensity ultrasound can cauterise bleeding arteries. His company, Ultrasound Technology, has developed a hand-held device that allows surgeons to cut through blood-rich organs and cauterise the cut at the same time. Crum hopes to test it in humans this year.
Weak ultrasound beams can also be used to spot the fast flow of blood characteristic of a bleeding artery. The US government's Defense Advanced Research Projects Agency (DARPA) is funding a project to combine the two ideas, which will result in the Deep Bleeder Acoustic Coagulation system - a portable device that uses ultrasound to both spot and seal bleeding blood vessels.
The device will consist of an array of ultrasound transceivers built into a cuff that can be wrapped round an injured limb. Transceivers emitting low power ultrasound will scan for reflections from damaged arteries. If they spot a leaking blood vessel, the transceivers zap it. To avoid damage to healthy tissue, several beams are carefully focused to meet inside the body where their combined heat will seal the tear.
4 Spider vs gecko
Peter Parker makes it look easy, but replicating his rooftop antics is so difficult it has had researchers climbing the walls for years. The problem is clear: the gloves and shoes of any Spider-Man suit must be able to support the weight of an average person while dangling from the side of a skyscraper. And of course hands and feet must also peel off easily when required - superglue is not an option.
For inspiration, researchers have turned to geckos rather than spiders. In 2003, Andre Geim at the University of Manchester, UK, designed a material with microscopic hairs that mimic those found on geckos' feet. Intermolecular van der Waals forces, which take effect on tiny scales, encourage each hair to stick to the wall and, because a gecko's feet are coated with millions of these hairs, the result is a powerful force of attraction. Geim's material has hairs made from a substance called kapton, and 1-centimetre-square of it, if pressed hard against a vertical surface, can support 1 kilogram.
But there may be problems scaling the materials up to a useful size. For example, the hairs need to be longer to provide a large enough surface area to support a person, and long hairs tend to tangle. Nicola Pugno at the Polytechnic University of Turin in Italy might have the answer. In 2007, he came up with a fir tree-like design, with long carbon nanotubes forming a trunk while shorter nanotubes branched off sideways. He has now made gloves that can support around 10 kilograms each.
Nature still has the upper hand, however. Dirt among the artificial hairs would compromise sticking ability. Geckos feet are self-cleaning, a trick way beyond current designs.
5 You power
Your cellphone is a marvel of the modern age. Yet no matter how sophisticated it is, it's useless the moment it runs out of juice. But what if you could dispense with batteries and simply gather all the energy your gadget needs from the world around you?
For a start, you could plug it into your shirt. In 2008, Zhong Lin Wang at the Georgia Institute of Technology in Atlanta wove a fabric made from zinc-oxide nanowires grown on strands of Kevlar. Each time the material is bent or squeezed, it generates a tiny current. Wang and his team found they could harvest it by coating each fibre with a film of metal.
Gadgets implanted inside your body, such as pacemakers, could be powered by you. David Tran's team at Stanford University, California, have devised a heart-powered electricity generator. The gadget produces electricity by forcing a small magnet back and forth through a tiny wire coil. The magnet is housed in a liquid-filled silicone tube with a balloon attached to each end, and the whole device is placed within the heart. As the heart beats, the balloons are squeezed in turn, forcing the liquid - and the magnet - back and forwards through the tube.
Adam Heller at the University of Texas, Austin, has built a fuel cell that can be implanted in an artery and which uses glucose in the blood as fuel.
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