Issue no. 10, 2009
Published: Mar 13, 2009 |
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 New batteries recharge in seconds |
| Coatings that 'self-heal' in sun |
| Internet at risk from 'wiretapping', says web inventor |
| Society's vital networks prone to 'explosive' changes |
| Device turns pink before you do |
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| New batteries recharge in seconds |
MIT engineers have found a way to make lithium batteries that are
smaller, lighter, longer lasting and capable of recharging in seconds.
The researchers believe the quick-charging batteries could open up new
applications, including better batteries for electric cars. And because
they use older materials in a new way, the batteries could be available
for sale in two to three years.
Current rechargeable lithium batteries can store large amounts of
energy, making them long-running. But they are stingy about releasing
their power, making them discharge energy slowly and require hours to
recharge. Scientists traditionally have blamed slow-moving lithium ions
- which carry charge across the battery - for this sluggishness.
However, about five years ago MIT scientists discovered that lithium
ions in traditional lithium iron phosphate battery material actually
move quite quickly. They found that lithium ions travel through tunnels
accessed from the surface of the material. If a lithium ion at the
surface is directly in front of a tunnel entrance, it can quickly
deliver a charge. But if the ion is not at the entrance, it cannot
easily move there, making it less efficient at delivering a charge.
The team remedied this by revamping the battery recipe. This created
many smooth tunnels in the material that allow the ions to slip in and
out easily. Using their new processing technique, the team made a small
battery that could be fully charged in 10 to 20 seconds. |
| Reuters / Nature
Mar 12, 2009 |
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| Coatings that 'self-heal' in sun |
Scientists at the University of Southern Mississippi have devised a
coating that when scratched heals itself upon exposure to sunlight.
The secret of the material lies in using molecules made from chitosan,
which is derived from the shells of crabs and other crustaceans. In the
event of a scratch, ultraviolet light drives a chemical reaction that
patches the damage.
The researchers designed molecules joining ring-shaped molecules called
oxetane with chitosan. The custom-made molecules were added to a
standard mix of polyurethane, a popular varnishing material that is also
used in products ranging from soft furnishings to swimsuits.
Scratches or damage to the polyurethane coat split the oxetane rings,
revealing loose ends that are highly likely to chemically react. In the
ultraviolet light provided by the sun, the chitosan molecules split in
two, joining to the oxetane's reactive ends. The researchers found their
coatings were able to fully heal themselves in just 30 minutes. |
| BBC News / Science
Mar 12, 2009 |
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| Internet at risk from 'wiretapping', says web inventor |
The ever-increasing power of computers that is helping the internet to
grow is also threatening its future. That was the warning delivered by
Tim Berners-Lee, the web's inventor, and online security specialists at
the Houses of Parliament in London this week. Their concerns are centred
on deep packet inspection (DPI), a technique that makes it possible to
peer inside packets of data transmitted across the internet.
DPI is already being used for commercial gain, without the consent of
users. Companies try to sell DPI-acquired data to firms that can use it
- for example, to target online adverts. DPI is also used by the Chinese
government to enforce its web censorship programme, sometimes called the
Great Firewall of China.
Berners-Lee has no issue with targeted adverts, which he said offered
online users an improved service, but is uncomfortable with using DPI to
provide them. He likened DPI to wiretapping, and pointed out that
companies could use it to learn a huge amount about our 'lives, hates
and fears'. One example he gave was that the web is often the first
point of call for people with health concerns.
DPI has become possible thanks to improvements in computing power, which
allows internet servers to relay data and simultaneously snoop inside
data packets. Until recently that was beyond the capabilities of the
available technology. |
| New Scientist
Mar 11, 2009 |
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| Society's vital networks prone to 'explosive' changes |
Computer scientists at the University of California have found that
random networks - the mathematical description for networks we
experience everyday in forms such as the internet and global flight
connections - have the potential for extreme behaviour never seen
before. Their findings might lead to improved understanding of how to
control such networks - for example, to halt the spread of epidemics or
improve the efficiency of delivery networks.
The researchers have been playing a Buckaroo-style game, adding more and
more connections between nodes in a network to see what happens.
Networks that grow randomly - such as the internet - usually rapidly and
smoothly gain a central backbone of connections that make it simple to
travel between any two points in a fully connected structure. The team
has used simulations to find a way to grow a network randomly, but
significantly delay the emergence of that backbone. But rather like the
mule in Buckaroo, when the network does become fully connected it is
with an explosive kick rather than a gradual change.
Random networks are usually grown by selecting two nodes at random to
become connected. Instead the team pick two pairs of random nodes, but
only connect one of them - the pair with the fewest pre-existing
connections to other nodes. The result is that for a long time the
network grows, but does not become fully connected. Instead it contains
a large number of unconnected chunks. Eventually, the addition of just
one link triggers an instantaneous phase change and the network becomes
fully connected. |
| New Scientist / Science
Mar 13, 2009 |
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| Device turns pink before you do |
Researchers at the University of Strathclyde, UK, have developed an
indicator that turns an appropriate shade of pink to alert wearers of
sunburn. The thin film device could be worn as a wrist band to warn
wearers they risk receiving a potentially harmful dose of UV rays.
UV rays drive a chemical reaction in the indicator, releasing an acid
into a dye, and causing it to change colour. Other indicators are
already available that detect and measure UV. But what is special about
the new one is that it can be adjusted to give an instant signal at the
point when sun exposure is about to cause damage, according to its
inventors.
The researchers have made a prototype of the film, combining a dye that
gradually changes colour from yellow to blue, and a central strip of dye
that turns pink. The device could also be adapted to different skin
types; adding an alkali to the dye would increase the delay before the
colour change. |
| BBC News / Chemical Communications
Mar 12, 2009 |
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