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Innovation & Technology
Weekly |
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This is the online version of the latest
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This week's headlines:
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Nanotech 'fuse' for novel battery |
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Shoddy construction beats precision in quantum world |
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Electric signals can propagate through an insulator |
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Nanotube cuff is 'solar cell' for exhaust pipes |
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Italy to host Europe's biggest solar plant |
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Lip reading mobile promises end to noisy phone calls |
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The green revolution sweeps into the bathroom |
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| Nanotech 'fuse' for novel battery |
| Minuscule tubes coated with a chemical fuel can act as a power source
with 100 times more electrical power by weight than conventional
batteries. As these nano-scale 'fuses' burn, they drive an electrical
current along their length at staggering speeds. The never-before-seen
phenomenon could lead to a raft of energy applications.
Researchers at MIT say that unlike normal batteries, the nanotubes never
lose their stored energy if left to sit. The team coated their nanotubes
with a chemical fuel known as cyclotrimethylene trinitramine. They used
a laser or an electric spark to set off the reaction in a bundle of
coated carbon nanotubes, filming the results using a high-speed camera.
But they also found that, through a mechanism that is still poorly
understood, the process creates a useful voltage - a phenomenon they
have dubbed 'thermopower waves'. Their nanotube bundles carry, gram for
gram, up to 100 times as much energy as a standard lithium-ion battery.
Since just a tiny amount of energy is needed to start the reaction
before it becomes self-sustaining, it could be initiated in a small
device with the energy in the push of a finger, according to the
researchers. And unlike standard batteries, the stored energy would not
leak away over time, and requires none of the toxic, non-renewable
metals in many batteries. |
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| Shoddy construction beats precision in quantum world |
| Haphazard construction rarely beats a precision build, but in the
topsy-turvy quantum world it pays to aim for imperfection. Physicists at
the Technical University of Denmark in Lyngby were working on one of the
trickiest of the problems that stand in the way of quantum communication
networks - systems that would carry messages by shuttling photons
'entangled' with atoms from place to place, offering theoretically
unbreakable security.
Creating an information-carrying entangled photon is not simple, because
light and matter don't normally interact. In the past physicists have
set up a quantum cage fight, trapping a photon and a single atom in a
confined space long enough to boost the likelihood that they will become
entangled. They use a nanoscale hall of metallic or semiconducting
mirrors, which confine the photon. When it finally escapes, it carries
the atom's information with it.
Fashioning precise mirrored traps is skilled work, though, which gives
the delicate devices a hefty price tag. But the team has shown that a
cheap gallium arsenide waveguide full of imperfections can trap and hold
photons just as effectively as one painstakingly built with nanoscale
precision.
Diederik Wiersma at the European Laboratory for Non-linear Spectroscopy
in Florence says the result suggests the imperfections that physicists
try so hard to eliminate might be part of the solution rather than the
problem. It constitutes a major step towards entangling photons with
their source in a system that can cope with disturbances caused by
design imperfections, he says. |
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| Electric signals can propagate through an insulator |
| An electric insulator, in the simplest terms, blocks the flow of
electric current. So it would be quite counterintuitive if a current on
one side of an insulator could produce voltage on the other. But that is
precisely what researchers at Tohoku University in Japan have found. The
electric current induces a collective excitation in the magnetic
insulator that can travel relatively long distances before unloading its
momentum to generate a voltage when it reaches an electric conductor.
Although insulators are impervious to the movement of electric current,
an electron is more than a simple charge carrier. It also features a
quantum-mechanical property known as spin, which can be thought of as
describing the pointing of its axis, like that of a spinning top, as
well as the orientation of its magnetic field. A wave of spin can ripple
through a magnetic insulator as a disruption in the ordered pointing of
the material's magnetic moments for relatively long distances.
The researchers laid two platinum conductors on a layer of yttrium iron
garnet, a magnetic insulator in which spin waves can travel centimetres.
The researchers showed that at the interface between the magnetic
insulator and the conductor, the two materials can exchange angular
momentum from spin. The spin of conduction electrons in platinum sets
off a lateral spin wave in the yttrium iron garnet below, which then
transfers spin into the other platinum film a millimetre away. |
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| Nanotube cuff is 'solar cell' for exhaust pipes |
| The hot gases passing through a vehicle's exhaust could be tapped to
generate power, using 'cuffs' made from a new carbon-nanotube-based
material. The 'thermocell', created at the University of Texas, produces
electricity at a similar cost per watt as commercial solar cells.
Each thermocell contains two electrodes, positioned at either end of a
temperature gradient: for example, one right next to a hot pipe and the
other closer to the surrounding cooler air. In between is a chemical
mix, in which the heat encourages chemical reactions that push electrons
around an external circuit. Ions in the mix shed electrons at the hotter
electrode and pick up electrons at the cooler one to complete the
circuit.
One of the team's thermocell designs is intended to be wrapped around a
hot pipe, inspired by the fact that heat leaks out from such structures
in many situations, such as chemical factories and power plants. The
'hot' electrode wrapped around the pipe is surrounded by a
heat-resistant layer, which is itself encased in a 'cold' electrode. An
aqueous solution can move through pores in the heat-resistant layer,
allowing ions to circulate between the reactions at the two electrodes. |
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| Italy to host Europe's biggest solar plant |
| Europe's most powerful solar power plant is set to start operations in
Italy later this year. The plant in Rovigo near Venice will take up
850,000 square metres and produce 72 megawatts, US company SunEdison
said in a statement announcing the start of construction.
The current biggest plant in Europe, located in Spain, produces 60
megawatts and the second biggest, in Germany, 50 megawatts.
Energy production will begin in the second half of 2010 and the plant
will be fully operational by the end of the year, said SunEdison, which
is working on the project in conjunction with Spanish banking giant
Santander.
During its first year of operations, the plant will cover the
electricity needs of 17,000 households and will prevent the emission of
41,000 tonnes of CO2 into the atmosphere. |
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| Lip reading mobile promises end to noisy phone calls |
| Technology that could see an end to the bane of many commuters - people
talking loudly on their mobile phones - has been shown off by
researchers. The prototype device, developed at Karlsruhe Institute of
Technology, could allow people to conduct silent phone conversations.
The technology measures the tiny electrical signals produced by muscles
used when someone speaks. The device can record these pulses even when a
person does not audibly utter any words and use them to generate
synthesised speech in another handset.
The device, on show at the Cebit electronics fair in Germany, relies on
a technique called electromyography which detects the electrical signals
from muscles. It is commonly used to diagnose certain diseases,
including those that involve nerve damage.
The prototype that is on display in Germany uses nine electrodes that
are stuck to a user's face. The electrical pulses are then passed to a
device which records and amplifies them before transmitting the signal
via Bluetooth to a laptop. There, software translates the signals into
text, which can then be spoken by a synthesiser. In the future the
technology could be packed in a mobile phone for instantaneous
communication. |
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| The green revolution sweeps into the bathroom |
| Environmentally-friendly 'NoMix' toilets that separate urine and faeces
could help to reduce pollution and save water. And support is growing
for the adoption of the techno-toilets.
NoMix toilets collect urine at the front and faeces at the back.
Separating urine before it reaches sewage treatment plants could reduce
the amount of nitrogen and phosphorus nutrients entering rivers and
triggering algal blooms, according to a paper in Environmental Science
and Technology. The collected urine could also be recycled as
agricultural fertiliser, conserving water.
Researchers at the Swiss Federal Institute of Aquatic Science and
Technology reviewed surveys of 2700 people across Europe, and found 80
per cent supported the idea of the toilets. What's more, three-quarters
of those surveyed said they found the comfort, smell and cleanliness of
the new loos equalled that of conventional toilets. |
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