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Issue no. 39, 2009
Published: Nov 27, 2009 |
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 Groundbreaking power plant generates electricity from water | | New hydrogen-storage method discovered | | Device spells doom for superbugs | | Paper-thin batteries made from algae | | Japan sets sights on solar power from space | | Superconductors can come in from the cold |
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| Groundbreaking power plant generates electricity from water |
The world's first osmotic power plant opened in Norway on Tuesday. The
plant uses a combination of freshwater, seawater and a special membrane
to generate electricity. The test plant, which currently only produces
enough electricity to power a coffee maker, is a test run of the
technology and will be used to develop larger, more efficient versions.
Osmotic power can be established anywhere clean freshwater runs into the
sea. Since it is not affected by weather fluctuations like wind or solar
energy, it is seen as a more reliable alternative energy source.
The prototype plant, built and operated by federally-owned utility
company Statkraft, uses osmosis to draw freshwater across a membrane and
toward the seawater side, creating pressure that drives a turbine and
produces electricity.
The utility hopes to improve the efficiency of the membrane from its
current 1 watt per square meter now to about 5 watts, which should make
osmotic power costs comparable to those from other renewable sources.
Statkraft estimates that osmotic power in Norway will eventually be able
to generate 10% of the country's power needs. The company plans to begin
building commercial osmotic power plants by 2015. |
| Statkraft / Reuters / Circle of Blue
Nov 25, 2009 |
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| New hydrogen-storage method discovered |
Scientists at the Carnegie Institution have found for the first time
that high pressure can be used to make a unique hydrogen-storage
material. The discovery paves the way for an entirely new way to
approach the hydrogen-storage problem.
The researchers found that the normally unreactive, noble gas xenon
combines with molecular hydrogen (H2) under pressure to form a
previously unknown solid with unusual bonding chemistry. The experiments
are the first time these elements have been combined to form a stable
compound. The discovery debuts a new family of materials, which could
boost new hydrogen technologies.
Xenon has some intriguing properties, including its use as an
anaesthesia, its ability to preserve biological tissues, and its
employment in lighting. Xenon is a noble gas, which means that it does
not typically react with other elements.
The researchers imaged the compound at varying pressures using X-ray
diffraction, infrared and Raman spectroscopy. When they looked at the
xenon part of the structure, they realised that the interaction of xenon
with the surrounding hydrogen was responsible for the unusual stability
and the continuous change in xenon-xenon distances as pressure was
adjusted from 41,000 to 255,000 atmospheres. |
| Science Daily / Nature Chemistry
Nov 25, 2009 |
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| Device spells doom for superbugs |
Researchers at the Max Planck Institute for Extraterrestrial Physics
have demonstrated a prototype device that can rid hands, feet, or even
underarms of bacteria, including the hospital superbug MRSA. The device
works by creating a plasma, which produces a cocktail of chemicals in
air that kill bacteria but are harmless to skin.
Plasmas are known as the fourth state of matter, after solid, liquid,
and gas. They are a soup of atoms that have had their electrons stripped
off by, for example, a high voltage. Plasmas are common elsewhere in the
cosmos, where high-energy processes produce them, and they are even
posited as a potential source of fusion energy.
But the new research focuses on so-called cold atmospheric plasmas.
Rather than turning a whole group of atoms into plasma, a more delicate
approach strips the electrons off just a few, sending them flying.
Collisions with nearby, unchanged atoms slows down the electrons and
charged atoms or ions they leave behind.
It has been known for some time that the resulting plasma is harmful to
bacteria, viruses, and fungi. The researchers have worked out the
precise details of the plasma production that effectively kills off such
bugs without doing harm to skin, and demonstrated a number of prototype
devices that do the job efficiently. |
| BBC News / New Journal of Physics
Nov 26, 2009 |
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| Paper-thin batteries made from algae |
Scientists worldwide are striving to develop thin, flexible,
lightweight, inexpensive, environmentally friendly batteries made
entirely from nonmetal parts. Among the most promising materials for
these batteries are conducting polymers. However, until now these have
impractical for use in batteries - for instance, their ability to hold a
charge often degrades over use.
The key to a new battery, developed by scientists at Uppsala University
in Sweden, turned out to be a green algae known as Cladophora. This
algae makes an unusual kind of cellulose typified by a very large
surface area, 100 times that of the cellulose found in paper. This
allowed researchers to dramatically increase the amount of conducting
polymer available for use in the new device, enabling it to better
recharge, hold and discharge electricity.
The new battery can hold 50 to 200% more charge than similar conducting
polymer batteries, and once better optimised, it might even be
competitive with commercial lithium batteries, the researchers say. It
also recharges much faster than a conventional rechargeable battery. The
new battery also shows a dramatic boost in the ability to hold a charge
over use. |
| MSNBC / LiveScience.com
Nov 25, 2009 |
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| Japan sets sights on solar power from space |
Japanese scientists are once again eyeing an off-world approach to
alternative energy - collecting solar energy from satellites in orbit
and beaming it down to Earth.
A space-based solar-power satellite - which could gather energy without
having to worry about clouds or night-time - has been a dream for
decades in both the US and Japan. But the costs of developing it has
meant that support has waxed and waned over the years. Now, however,
Japan has a new sense of mission. In June, it released a national space
plan calling for a programme to 'lead the world in space-based solar
power'. And earlier this month, scientists, engineers and policy-makers
met at Kyoto University to lay out development plans.
Few doubt that the project is technically possible. The well-understood
process starts with collecting solar energy with photovoltaic cells,
transferring that energy to antennas that transmit microwaves, then
receiving those microwaves with a 'rectifying antenna' that converts
them to electricity.
Researchers are hoping to launch a full-scale system by 2030, but costs
need to come down dramatically for it to be economically viable. |
| Nature
Nov 25, 2009 |
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| Superconductors can come in from the cold |
Superconducting wires allow electricity to flow with zero resistance, as
long as their temperature is below at least -123 °C. That is a major
obstacle, but does the whole of the wire have to be that cold? The
answer may be no, according to researchers at the University of
California, San Diego. They have calculated that provided some points
along the wire's length stay below the threshold temperature, the
material will superconduct.
For this to work, the wire's surface must be extremely clean, allowing
electrons to move freely and spread along the wire to create a uniform
temperature. A material with a critical temperature of -193 °C could
superconduct at room temperature, provided some sections were kept to
-253 °C, they found. In principle, the colder these refrigeration points
are, the fewer you need, according to the researchers.
The researchers are reluctant to proclaim the finding as the long-sought
solution to room-temperature superconductors, since refrigeration points
just 20 °C above absolute zero will be tricky to achieve. Still, the
theory could be tested with available technology. |
| New Scientist / Physical Review B
Nov 26, 2009 |
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