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Deuterium-tritium fusion diagram.
Source: Wikipedia
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Issue no. 4, 2010 Published: Jan 29, 2010 |
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Giant laser reaches key milestone for fusion | Using light to disinfect water | Venus Flytrap material captures radioactive waste | Bacteria rebuilt to make oil | Safety in numbers - a cloud-based immune system for computers | 'Superman' vision penetrates opaque glass | Shoes may have changed how we run | IPad? That's so 2002, Fujitsu says |
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| Giant laser reaches key milestone for fusion |
The world's largest laser is approaching the long-sought goal of
igniting a fusion reaction that produces more energy than the laser
delivers. Lasers are intended to do this by super-heating a fusion fuel
pellet until it implodes, heating and compressing its central core to
the temperatures and pressures needed for nuclear fusion.
Past experiments have been plagued by irregular implosions that wasted
most of the input energy. But now researchers at Lawrence Livermore
National Laboratory in California have managed to squeeze targets of
material into spheres rather than pancakes or more lopsided shapes,
paving the way for future attempts at fusion. The work was performed at
Livermore's 192-laser beam National Ignition Facility (NIF).
The team used targets that did not contain the key ingredients for
fusion - two isotopes of hydrogen known as deuterium and tritium. But
the symmetrical implosion of the targets suggests that NIF should be
able to ignite fusion with laser pulses of 1.2 to 1.3 megajoules - well
below its full 1.8-megajoule capacity.
Researchers spent last year slowly cranking up the output of the laser,
ultimately reaching a total energy of more than 1 megajoules. Now
they're pausing to mount new instruments on the 10-centimetre-thick
aluminium target chamber and to install giant concrete doors to contain
neutrons they expect to produce in future fusion experiments. In a few
months, they will begin testing a series of new targets designed to
assess beam interactions and compression. If all goes well, they could
try for fusion ignition by the end of the year. |
| New Scientist
Jan 28, 2010 |
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| Using light to disinfect water |
Getting access to clean drinking water is an ongoing problem for people
in developing countries. And even cities that have good water-treatment
systems are looking for better ways to deliver safer, cleaner water. Now
an international research team has developed a photocatalyst that
promises quick, effective water disinfection using sunlight or
artificial light. What's more, the photocatalyst keeps working after the
light is turned off, disinfecting water even in the dark.
It has long been known that irradiating water with high-intensity
ultraviolet light kills bacteria. The new photocatalyst, developed by
researchers at the University of Illinois, improves on that by using
light in the visible spectrum. It consists of fibres of titanium oxide
doped with nitrogen to make it absorb visible light. The researchers
added nanoparticles of palladium to the surface of the fibres, greatly
increasing the efficiency of the disinfection.
The researchers placed the photocatalist it in a solution containing a
high concentration of E. coli bacteria and then shone a halogen desk
lamp on the solution for varying lengths of time. After an hour, the
concentration of bacteria dropped from 10 million cells per litre to
just one cell per 10,000 litres. The researchers also shone light on the
fibres for 10 hours to simulate exposure to daylight and then stored
them in the dark for various times. Even after 24 hours, the
photocatalyst still killed bacteria. |
| Technology Review / Journal of Materials Chemistry
Jan 27, 2010 |
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| Venus Flytrap material captures radioactive waste |
Of all the radioactive isotopes left over from nuclear weapons testing
and nuclear power plants, cesium-137 is among the most dangerous. The
metal has a half-life of 30 years, enters the body quickly, and can
trigger cancer even decades after exposure. Removing cesium-137 from the
environment has proven difficult, but researchers say they have a
promising new way to clean it up: a flexible, porous solid that grabs
caesium ions much like a Venus flytrap ensnares its prey.
The new material is part of a class of materials made of spongelike
frameworks of inorganic elements. Researchers from Northwestern
University were working to create one of these inorganic frameworks,
possibly one that could be used to capture environmental contaminants.
The researchers made their framework from a mixture of gallium, tin, and
sulphur, which formed sheets with holes. They also added dimethylammonium
(DMA) ions. The sheets stacked atop one another with the holes running
up and down through the material and with the DMA ions sitting in
between the layers. The researchers thought that cesium-137 ions might
be able to wiggle through the holes into the heart of the solid and
trade places with the DMA, which exactly happened. But when they
attempted to flush out the caesium with other charged ions, such as
lithium and sodium, the caesium didn't exchange places as expected and
instead remained locked in the solid.
An x-ray snapshot of the material revealed that when the caesium enters,
it not only displaces DMA, it also binds to a sulphur atom in the
lattice. This tugs on the framework and pulls the holes closed, thereby
trapping the caesium inside, like a molecular Venus flytrap. |
| ScienceNow / Nature
Jan 26, 2010 |
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| Bacteria rebuilt to make oil |
Researchers from the US Department of Energy's Joint BioEnergy Institute
(JBEI) have engineered a common type of bacteria to produce biodiesel
from plants. The bioengineered E. coli bacteria could provide an
affordable path to greater energy independence.
The researchers modified the bacteria's genome to insert the coding for
producing an enzyme known as hemicellulase. That enzyme can break down
one of the ingredients of cellulosic feedstock, hemicellulose, into
smaller sugar molecules. E. coli bacteria are naturally programmed to
turn those sugars into fatty acids for building cell membranes - but
normally, each bacterium produces only as much of the fatty acids as it
needs. Researchers fiddled with that part of the genetic code, too,
turning the bacteria into little biodiesel factories.
The bacteria expelled droplets of oil into the fermentation vats, which
made extraction of the fuel relatively easy. The process could be
tweaked to produce other chemical products as well, ranging from jet
fuel to solvents and lubricants. |
| MSNBC / Nature
Jan 27, 2010 |
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| Safety in numbers - a cloud-based immune system for computers |
A new approach for managing bugs in computer software has been developed
developed by the Dependable Systems Lab at Ecole Polytechnique Fédérale
de Lausanne in Switzerland. The latest version of Dimmunix, available
for free download, enables entire networks of computers to cooperate in
order to collectively avoid the manifestations of bugs in software.
The approach, termed 'failure immunity', starts working the first time a
bug occurs - it saves a signature of the bug, then observes how the
computer reacts, and records a trace. When the bug is about to manifest
again, Dimmunix uses these traces to recognize the bug and automatically
alters the execution so the program continues to run smoothly. With
Dimmunix, a webbrowser learns how to avoid freezing a second time when
bugs associated with, for example, plug-ins occur. Going a step further,
the latest version uses cloud computing technology to take advantage of
networks and thereby inoculating entire communities of computers.
Dimmunix could be compared to a human immune system. Once the body is
infected, its immune system develops antibodies. Subsequently, when the
immune system encounters the same pathogen once again, the body
recognizes it and knows how to effectively fight the illness, according
to the developers. |
| PhysOrg / Ecole Polytechnique Fédérale de Lausanne
Jan 27, 2010 |
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| 'Superman' vision penetrates opaque glass |
Some things we consider opaque are slightly translucent, meaning some
light does in fact make it through. However, it is scattered so much by
bouncing around such materials' lattice of atoms that physicists thought
it was beyond practical use for seeing what is on the other side it.
By reverse engineering the scattering process, researchers at École
Supérieure de Physique et de Chimie Industrielles in Paris, France, were
able to reconstruct an image from light that had passed through the
opaque paint layer. That scattering is complex, but it's also regular:
the same light wave will always be scattered in the same way. The way a
particular object scatters light is known as its transmission matrix.
The team worked out the transmission matrix for their painted glass
slide by hitting it with a weak laser beam more than 1000 times,
changing the shape of the beam each time using a spatial light modulator
- the same device used to control the light emerging from a video
projector. A digital camera on the other side of the glass detected the
different scattering patterns produced each time. Comparing what it saw
with what had been done to the laser beam made it possible to measure
the paint's complete transmission matrix.
When a simple 256-pixel image was then projected onto the paint, a
person simply looking at the paint would see only an even glow. But the
team used knowledge of the transmission matrix to decode the faint,
noisy trace that reached the digital camera and reconstruct the image. |
| New Scientist / Physics Arxiv
Jan 28, 2010 |
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| Shoes may have changed how we run |
Wearing cushioned running shoes may have changed the way in which many
of us run, new research suggests. Using slow-motion footage, scientists
have discovered that experienced barefoot runners land very differently
from runners who wear shoes. The researchers showed that runners who
have trained barefoot tend to strike the ground with their forefoot or
mid-foot, rather than their heel.
The question of how best to support and protect a runner's feet is
something that has intrigued both scientists and sports shoe designers.
This analysis, the researchers said, took an evolutionary approach to
that question. The team used a combination of highly sensitive scales,
high speed cameras, and 3-D motion analysis to compare barefoot runners
to those wearing running shoes. Their results showed that 'shod' runners
tended to strike the ground with their heel first.
But experienced barefoot runners appear to have developed a different
way to prevent the pain, striking the ground with the forefoot or
mid-foot. The style adopted by barefoot runners may, in some respects,
be less damaging, according to the researchers. The footage also
demonstrated the specialised anatomy of the human foot, and caused the
team to propose that modern sports footwear may have altered how people
run. |
| BBC News / Nature
Jan 27, 2010 |
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| IPad? That's so 2002, Fujitsu says |
It's sleek. It's mobile. It has a touchscreen. It's Fujitsu's iPad from
2002. Sold mainly in the US, the multifunctional device helps shop
clerks verify prices, check real-time inventory data and close sales on
the go. Fujitsu, which applied for an iPad trademark in 2003, is
claiming first dibs, setting up a fight with Apple over the name of the
new tablet device that Apple plans to sell starting in March.
Fujitsu's application to trademark the iPad name stalled because of an
earlier filing by Mag-Tech, an information technology security company,
for a handheld number-encrypting device. The US Patent and Trademark
Office listed Fujitsu's application as abandoned in early 2009, but the
company revived its application in June. The following month, Apple used
a proxy to apply for an international trademark for the iPad. Apple has
until Feb 28 to say whether it will oppose Fujitsu's claims to the name.
While the dispute between Fujitsu and Apple centres on the US, there are
other iPads around the world. The German conglomerate Siemens uses the
name for engines and motors, while a Canadian lingerie company, Coconut
Grove Pads, has the right to market iPad padded bras. |
| New York Times
Jan 28, 2010 |
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