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Issue no. 23, 2011
Published: Jul 01, 2011 |
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 Scientists use inkjet printing to produce solar cells | | IBM announces computer memory breakthrough | | Aircraft punch 50-kilometre-wide holes in clouds | | Pen with silver ink draws circuits on the fly | | Japan experts design superelastic alloy, may resist quakes | | Shrimp eyes inspire optical technology | | E.coli seen spawning biofuel in five years |
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| Scientists use inkjet printing to produce solar cells |
Solar energy may soon become easier to capture, say researchers who have
developed a novel method to produce solar cells using inkjet printing.
Oregon State University researchers have come up with a technology
similar to that commonly used to print documents and photos. They say
their method is quicker and less expensive than traditional solar cell
manufacturing techniques. It could also reduce raw material waste by
90%, they add.
As people move away from conventional combustion-type technologies, more
attention is paid to renewable energy types, and solar energy is one of
them. It is known as a clean and sustainable form of energy, but this is
offset by the manufacture of solar panels which is an expensive and
complicated process. Finding a balance between costs of production and
efficiency could become key to future manufacture of solar cells, and
many scientists around the world have been concentrating on developing
new materials and methods to do that. The recent inkjet approach is one
of those novel methods.
The team used chalcopyrite - a material composed of copper, indium,
gallium and selenium and also known as CIGS. It has a much greater solar
efficiency than silicon, currently used to manufacture solar panels. The
researchers then printed chalcopyrite onto the surface of the cell,
applying a technique similar to a common inkjet approach, but with a
special type of ink. They managed to produce solar cells of 5%
efficiency - and say that in future, they will aim to increase this
figure to about 12% to make the product commercially viable. |
| BBC News
Jun 30, 2011 |
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| IBM announces computer memory breakthrough |
IBM this week announced a breakthrough in computer memory technology,
which may lead to the development of solid-state chips that can store as
much data as NAND flash technology but with 100 times the performance
and vastly greater lifespan.
Currently, NAND flash memory products, such as solid state drives
(SSDs), have write rates as high as 2Gbit/sec. IBM said it has produced
phase-change memory (PCM) chips that can store two bits of data per cell
without data corruption problems, something that has plagued PCM
development from the start.
Like NAND flash memory PCM is nonvolatile - meaning it retains data
after its power supply is shut down. Unlike NAND flash, PCM memory does
not require that existing data be marked for deletion prior to new data
being written to it - a process known to as an erase-write cycle.
Erase-write cycles slow NAND flash performance and, over time, wear it
out, giving it a lifespan that ranges from 5,000 to 10,000 write cycles
in consumer products and up to 100,000 cycles in enterprise-class
products. PCM can sustain up to 5 million write cycles, says IBM.
Besides applications for enterprises and in the cloud, PCM may also
serve as an extension for DRAM. While DRAM will continue to be used as
the closest memory device to the CPU for the most active data, PCM, with
its greater capacity, can be used for less frequently accessed data. |
| ComputerWorld
Jun 30, 2011 |
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| Aircraft punch 50-kilometre-wide holes in clouds |
Giant circular holes in clouds are caused by aircraft flying through,
but until now no one could explain how they got so big. Researchers at
the National Center for Atmospheric Research in Boulder, Colorado, used
a satellite to track 92 cloud holes over Texas over 4 hours in 2007.
The holes grew substantially within an hour, before slowly shrinking.
The majority of the holes reached a diameter of between 10 and 50 km. It
was clear how the holes got started. The clouds were supercooled,
meaning their water was in liquid form despite being below 0 °C. Water
can stay supercooled for a long time if left alone, but any disturbance
turns it into ice. A plane flying through is more than enough to trigger
freezing, at which point the resulting ice crystals fall away, leaving a
hole. But that should only form a small hole.
The researchers wondered if a side effect of making ice was causing the
holes to grow. When liquid freezes it releases a little heat. This would
cause the warmer air around the ice crystals to rise and the surrounding
air to fall, starting a circulating current. As the falling air moved
into a warmer zone its previously supercooled liquid water would
evaporate. The circulating air would carry this effect outwards,
disrupting more of the cloud and triggering further evaporation. A
cascade would be set off, causing the rapid expansion of the hole.
To test this idea, the team ran a detailed computer model of the
internal workings of a cloud. They introduced a line of ice crystals
such as that produced by an aircraft and watched as a hole grew to a
diameter of 4.4 kilometres in 90 minutes. But when they turned off the
heating effect of making ice, the hole only grew slowly. If they also
removed the effects of evaporation, the hole didn't grow at all. The
holes could help to explain why some clouds produce rain but others
don't. The key may be a few ice crystals, which 'suck up' water from
their surroundings and create droplets large enough to fall. |
| New Scientist / Science
Jun 30, 2011 |
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| Pen with silver ink draws circuits on the fly |
Putting pen to paper is all it took for engineers at the University of
Illinois to create a flexible array of interconnected LEDs. Their pen
dispenses a silver solution that allows the user to draw functioning
electrical circuits on a wide variety of surfaces. A flexible array of
LEDs was mounted on paper, and then interconnected by hand-drawn silver
ink lines.
Metallic inks have previously been used in inkjet printers to print
electronic circuits, but the pen is much more mobile and can be used
instantly on wide variety of surfaces at a much lower cost. The ink also
maintains conductivity when folded, opening up applications in art and
fashion, disposable electronics and folded, three-dimensional devices.
'Pen-based printing allows one to construct electronic devices
on-the-fly, using very low cost, ubiquitous printing tools,' said
Jennifer Lewis, one of the lead researchers and director of the
Frederick Seitz Materials Research Laboratory at the University of
Illinois. |
| New Scientist
Jun 29, 2011 |
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| Japan experts design superelastic alloy, may resist quakes |
Researchers in Japan have developed a superelastic alloy, which can
spring back to its original form in extreme temperatures. They hope it
may be used in buildings to absorb shocks from earthquakes.
The researchers from Tohoku University added a small amount of nickel to
an iron-based alloy, and found that the new material can recover its
original shape at any temperature from -196 to 240 degrees Celsius. The
new material was far more elastic than other superelastic alloys, which
cannot revert to their original form outside the -20 to 80 degrees
Celsius range.
The material may be used in environments that are constantly exposed to
extreme temperatures, such as joints and controls in cars, planes and
spacecraft. It may also help buildings cushion stress and violent
movement in earthquakes, according to the researchers. |
| Reuters / Science
Jun 30, 2011 |
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| Shrimp eyes inspire optical technology |
The future of CD and DVD technology may be found in the eyes of peacock
mantis shrimp, an international team of engineers recently reported. The
shrimp are one of the few animals in the world that are able to see
circularly polarised light, the type of light used to make 3-D movies.
Scientists believe this ability is related to sexual signalling.
The researchers looked at these eyes in a bid to build a better
waveplate. Waveplates are optical devices that alter the polarisation
state of light that travel through them. These devices are typically
made from minerals such as quartz, calcite, or birefringent polymers. In
some cases, to create the range and transparency required, two different
materials are stacked or joined. Sometimes, though, this type of
construction delaminates - it comes apart at the seams.
The method pioneered by the team mimics the lens construction of peacock
mantis shrimp. These multilayered materials are suitable for waveplates
in the visible light spectrum and cannot delaminate because they are
manufactured as one piece. The waveplate consists of two layers of
nanorods; each layer deposited using different methods. One method
produces a layer of needle-like nanorods that are parallel to each other
and all slanted in the same direction. The second method produces
parallel nanorods that are upright. These layers are stacked together to
make a waveplate. Eventually, this technology could lead to improved
data storage devices and even higher high definition movies.
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| MSNBC
Jun 27, 2011 |
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| E.coli seen spawning biofuel in five years |
The bacteria behind food poisoning worldwide, the mighty E.coli, could
be turned into a commercially available biofuel in five years, a US
scientist told technology industry and government leaders. Several
companies are working on the technology, which has been proven in
laboratories but is not yet yielding enough fuel to be commercially
viable, scientist Jay Keasling told the Aspen Ideas Festival on Tuesday.
Keasling, chief executive officer of the US Department of Energy's Joint
BioEnergy Institute, has pioneered research in biofuels based on
substances ranging from yeast to E.coli and expects E.coli fuel
production to improve. Already, a similar technology is using E.coli
bacteria to make plastics that are finding their way to stores in
products including carpets. Although there is nothing dangerous in
E.coli plastic, companies usually don't mention the unusual origins to
consumers, he said.
When ingested by humans, E.coli can be dangerous, even fatal. Earlier
this year, an outbreak in Germany caused widespread illness and panic,
and led to more than 30 deaths. While biofuels eventually have enormous
potential for reducing fossil-fuel consumption, 'it's going to be a long
time before biofuels are a serious challenge to petroleum,' he said.
Reaching critical mass was likely to take at least two decades, he said. |
| Reuters
Jun 29, 2011 |
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