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Issue no. 12, 2009
Published: Mar 27, 2009 |
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 Neutron tracks revive hopes for cold fusion | | China experiments with solar-thermal power | | Artificial cartilage performs better than the real thing | | Robotic fish designed to fight pollution | | Ice that burns could be a green fossil fuel | | Microwaves 'improve fog landings' | | Scientists build a brain on a chip |
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| Neutron tracks revive hopes for cold fusion |
Twenty years to the day that two electrochemists ignited controversy by
announcing signs of cold fusion at an infamous press conference in Utah,
a separate team has made a similar claim in the same US state. But this
time, the evidence is being taken more seriously.
Researchers at Space and Naval Warfare Systems Command (SPAWAR) in San
Diego, California, are claiming to have made a 'significant' discovery -
clear evidence of the products of cold fusion. Using a similar setup as
in the 1989 experiment, the researchers found the 'tracks' left behind
by high-energy neutrons, which, they suggest, emerge from the fusion of
a deuterium and tritium atom.
The team used a low-tech particle detector: a plastic called CR-39 that
is otherwise used for spectacle lenses. When CR-39 is bombarded with
subatomic charged particles, a small pit forms in the material with each
impact. The researchers placed a sample of CR-39 in contact with a gold
or nickel cathode in an electrochemical cell filled with a mixture of
palladium chloride, lithium chloride and deuterium oxide (D2O),
so-called 'heavy water'. When a current was passed through the cell,
palladium and deuterium became deposited on the cathode.
After two to three weeks, the team found a small number of 'triple
tracks' in the plastic - three 8-micrometre-wide pits radiating from a
point. The team says such a pattern occurs when a high-energy neutron
strikes a carbon atom inside the plastic and shatters it into three
charged alpha particles that rip through the plastic leaving tracks. No
such tracks were seen if the experiment was repeated using normal rather
than heavy water. |
| New Scientist / Naturwissenschaft
Mar 23, 2009 |
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| China experiments with solar-thermal power |
Construction is due to start later this month on an experimental
solar-thermal power plant in the shadow of China's Great Wall that will
bring clean energy to 30,000 households by 2010. Built on the outskirts
of Beijing, the 1.5 MW Dahan plant will cover an area the size of 10
football pitches, and will serve as a platform for experiments on
different solar-power technologies.
Unlike photovoltaic solar panels, which produce electricity directly
from sunlight, solar-thermal power is based on an array of mirrors that
focus the Sun's rays onto a receiver. Several solar-thermal plants are
already operating elsewhere in the world but the Dahan facility will be
the first of its kind in Asia.
The Chinese design relies on 100 curved 'heliostat' mirrors that track
the Sun's movement across the sky and redirect light onto a receiver
atop a 100m-high central tower. Water flowing through the receiver is
transformed into superheated steam, which can then drive electricity
generating turbines as in a conventional power plant. Surplus energy is
stored as heat, with a tank of synthetic oil serving as a reservoir for
the high temperature heat needed to produce superheated steam, and a
second system 'downstream' to store heat at lower temperatures. |
| Physics World
Mar 26, 2009 |
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| Artificial cartilage performs better than the real thing |
The smooth cartilage that covers the ends of long bones provides a level
of lubrication that artificial alternatives haven't been able to rival -
until now. Researchers at the Weizmann Institute of Science in Rehovot,
Israel, say their lubricating layers of 'molecular brushes' can
outperform nature under the highest pressures encountered within joints,
with potentially important implications for joint replacement surgery.
While it is possible to match cartilage's slick properties at low
pressure, at the high pressures found in joints synthetic alternatives
'seize up'. The researchers developed molecular brushes that slide past
each other with friction coefficients that match those of cartilage. In
some respects, they perform even better: the brushes remain highly
effective even at pressures of 7.5 megapascals. Cartilage performs well
only up to around 5 megapascals.
Each 60-nanometre-long brush filament has a polymer backbone from which
small molecular groups stick out. Those synthetic groups are very
similar to the lipids found in cell membranes, although they're neutral
overall, they are positively charged at one end and negatively charged
at the other. In a watery environment, each of these molecular groups
attracts up to 25 water molecules through electrostatic forces, so the
filament as a whole develops a slick watery sheath. These sheathes
ensure that the brushes are lubricated as they rub past each other, even
when firmly pressed together to mimic the pressures at bone joints. |
| New Scientist / Science
Mar 26, 2009 |
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| Robotic fish designed to fight pollution |
Robotic fish 1.5 meters long - roughly the size of a seal - and able to
navigate independently without any human interaction have been developed
by British scientists at engineering company BMT Group and Essex
University to detect pollution. If next year's trial of the first five
carp-shaped robots in the Spanish port of Gijon is successful, the team
hopes they will be used in rivers, lakes and seas across the world.
The life-like creatures, which will mimic the undulating movement of
real fish, will be equipped with tiny chemical sensors to find the
source of potentially hazardous pollutants in the water, such as leaks
from vessels in the port or underwater pipelines.
The fish will communicate with each other using ultrasonics and
information will be transmitted to the port's control centre via WiFi
from the "charging hub' where the fish can charge their batteries. This
will enable the authorities to map in real time the source and scale of
the pollution.
Unlike previous robotic fish that work with remote controls, these will
have autonomous navigation capabilities, enabling them to swim
independently around the port without any human interaction. This will
also enable them to return automatically to their hub to be recharged
when battery life is low. |
| Daily Galaxy / BMT Group
Mar 24, 2009 |
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| Ice that burns could be a green fossil fuel |
Natural gas locked up in water crystals could be a source of enormous
amounts of energy - and if a new technology delivers what scientists are
claiming, then it could even be emissions-free too.
Clathrate hydrate looks like regular ice. However, the water molecules
are organised into 'cages', which trap individual molecules of methane
inside them. Compared to other fossil fuels, methane releases less CO2
per unit of energy generated. Nevertheless, burning it still releases
CO2 and thus drives climate change.
However, according to research by the United States Geological Survey, a
new method of extracting the methane could effectively make it a
carbon-neutral fossil fuel. Due to their physical structure, clathrate
hydrate cages 'prefer' to have CO2 at their cores, so if CO2 is pumped
into the hydrate, it spontaneously takes the methane's place. As a
result, it should be possible to simultaneously extract methane and
store CO2.
The exchange process has been shown to work in the lab. The US
Department of Energy is now working with the oil company ConocoPhillips
on a trial in Alaska, to test whether the technique can be scaled up. |
| New Scientist / National meeting of the American Chemical Society
Mar 26, 2009 |
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| Microwaves 'improve fog landings' |
Passengers flying into UK's Heathrow airport in fog or poor visibility
will be guided in using a new system. The new Microwave Landing System
(MLS) is less prone to interference, meaning aircraft can now land at a
faster rate. Initially, the system will be used by British Airways'
Airbus 320s, although other airlines are expected to follow.
On a clear day, about 44 planes an hour land at Heathrow. However, if
the visibility drops and aircraft have to use the existing
Instrument Landing System (ILS) to land on full autopilot, that figure
falls to 24 aircraft an hour. This is because the radio transmitter at
the end of the runway needs good line of sight to the approaching
aircraft, but because it is at the far end of the runway, planes have to
land and taxi clear before a full signal is restored. The new MLS allows
an extra six aircraft an hour to land.
Designed in the 1940s, the ILS system uses two radio signals - one
transmitted at the far end of the runway and the other at the side on
two separate frequencies - to guide the aircraft down on an approach
making a horizontal angle of three degrees with the runway. MLS, on the
other hand, uses a single frequency in a band far removed from that of
the ILS system to broadcast the horizontal and vertical angle data to
the aircraft. It will not be implementing so-called curved approaches.
Rather than the three degree approach in line with the runway, aircraft
could - in theory - approach the airport from up to 40-degrees off the
end of the runway, lining up with it a mile or so before touchdown. |
| BBC News
Mar 25, 2009 |
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| Scientists build a brain on a chip |
German scientists have perfected a new chip design which they claim can
function like a human brain, but much faster.
The chip is built using 200,000 neurons linked by 50 million synaptic
connections to mimic the way that data is transferred biologically.
While it is much less powerful than the human brain at present, there
are no technical limitations to scaling the size of the design.
It was developed by a team at Heidelberg University, as part of the Fast
Analog Computing with Emergent Transient States project. The chip does
not act as a brain per se, but simulates the parallel data handling that
the brain displays.
Much of the previous research into parallel data handling was done using
software simulations, but this requires a lot of computing power.
Designing a physical chip is more efficient, and up to 100,000 times
faster. according to the researchers. The team now plans to scale the
design up to a superchip with a total of a billion neurons. |
| VNUnet UK
Mar 26, 2009 |
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