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Issue no. 18, 2009
Published: May 29, 2009 |
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 Scientists invent memory storage good for a billion years | | Breathing batteries could store 10 times the energy | | Data storage enters the 'fifth dimension' | | Sperm-like nanopropeller is smallest swimmer ever | | Drain rice fields to cut methane, say scientists | | New web tool Wolfram Alpha launches | | A Facebook profile can reveal the real you |
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| Scientists invent memory storage good for a billion years |
Scientists are reporting successful tests of a new memory device that
could allow terabytes of data to be stored without corruption for
millions of years.
The device is an iron nanoparticle, 1/50,000 the width of a human hair,
enclosed in a hollow carbon nanotube. The iron can be shuttled back and
forth within the tube as an effective way to store data.
The team says it is achievable to build storage devices capable of
carrying a terabyte of information per square inch, making it more
effective than current techniques. However, the data will also be almost
incorruptible and should remain available for a billion years or more.
Current memory technologies are nowhere near as long lasting.
Conventional flash memory usually fails after around three to five
years. One of researchers behind the invention, notes that the Doomsday
Book written on vellum has so far lasted over 900 years, whereas the
digital version of the book, encoded in 1986, failed in less than 20
years. |
| VNUnet UK / Nano Letters (forthcoming)
May 27, 2009 |
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| Breathing batteries could store 10 times the energy |
The lithium ion batteries used in laptops and cellphones are approaching
their technological limits. But chemists in the UK say that there's a
way to break through the looming energy capacity barrier - let the
batteries 'breathe' oxygen from the air.
A standard lithium ion battery contains a negative electrode of
graphite, a positive electrode of lithium cobalt oxide, and a lithium
salt-containing electrolyte. Lithium ions shuttle between the two
electrodes during charging and discharging, sending electrons around the
external circuit to power a gadget in the process. The problem is that
the lithium cobalt oxide is bulky and heavy.
The new battery has a higher energy density than existing lithium ion
batteries because it no longer contains dense lithium cobalt oxide.
Instead, the positive electrode is made from lightweight porous carbon,
and the lithium ions are packed into the electrolyte which floods into
the spongy material. When the battery is discharged, oxygen from the air
also floods through a membrane into the porous carbon, where it reacts
with lithium ions in the electrolyte and electrons from the external
circuit to form a solid lithium oxide.
The solid lithium oxide gradually fills the pore spaces inside the
carbon electrode as the battery discharges. But when the battery is
recharged the lithium oxide decomposes again, releasing lithium ions
again and freeing up pore space in the carbon. The oxygen is released
back to the atmosphere. The team's prototype device has a
capacity-to-weight ratio of 4000 milliamp hours per gram - eight times
that of a cellphone battery. |
| New Scientist
May 19, 2009 |
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| Data storage enters the 'fifth dimension' |
The first DVD-sized discs with storage capacities well over one terabyte
could be available in as little as five years, according to researchers
in Australia who have invented a new storage technique. The concept,
which the researchers have already demonstrated on test media, uses
layers of gold nanorods to achieve 'five-dimensional recording'.
Optical discs, such as CDs and DVDs, store data as a spiral track of
microscopic pits etched onto their surface. To reach higher capacities,
particularly above 1 Tb per disc, scientists believe they will need to
be able to record in more 'dimensions' than used in today's
three-dimensional storage technique. In recent years there has been
success in adding one extra dimension in the form of sensitivity to
either the polarisation or colour of the laser light, a technique called
multiplexing.
Now, however, researchers from Swinburne University of Technology in
Melbourne have combined both types of multiplexing for five-dimensional
recording. For its recording media the Swinburne group use gold
nanorods, which respond to different colours and polarisations depending
on their apparent size and orientation. When a collection of these
nanorods are irradiated with laser light, only those that are aligned to
the light's polarisation and have an absorption cross-section matching
the light's wavelength will absorb it, melt and change in shape. Because
there are nanorods left unaffected after one recording, more recording
cycles can still take place. |
| PhysicsWorld / Nature
May 20, 2009 |
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| Sperm-like nanopropeller is smallest swimmer ever |
Remote-controlled nano-devices that look like sperm but mimic the
corkscrew motion of flagella may one day deliver drugs to where they are
needed in the body. Flagella are the structures some bacteria use to
swim through water. Because water is syrupy at small scales, ordinary
swimming motions don't work well. Instead, flagella use a corkscrew
motion to drive bacteria through the water.
The motion of flagella inspired researchers at Harvard University to
create their nanopropellers. Made of glass, each has a spherical head
200 to 300 nanometres across and a corkscrew-shaped tail 1 to 2
micrometres long - less than one-tenth the length of a human sperm. To
make their propellers, the team covered a silicon wafer with glass
beads, before depositing a vapour of silicon dioxide onto them. While
doing so they spun the wafer, causing the silicon dioxide to form
corkscrew-shaped tails on each bead. Finally, once the silicon dioxide
had solidified they covered one side of the nanopropellers with cobalt.
Cobalt is magnetic, so when an external magnetic field is applied the
propellers line up with the field. By making the field rotate, the
researchers were able to make the propellers rotate with it,
corkscrewing through the water at up to 40 micrometres per second. By
changing the magnetic field in three dimensions the propellers can be
precisely steered. Another benefit to using an external magnetic field
to move the propellers is that the swimmers aren't limited by internal
energy sources. It also means that the nanopropeller has no moving
parts, unlike microbots. |
| New Scientist / Nano Letters
May 27, 2009 |
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| Drain rice fields to cut methane, say scientists |
Global methane emissions from rice paddies could be cut by 30 per cent
if fields are drained at least once during the growing season and rice
crop waste is applied off-season, according to a study by the Chinese
Academy of Sciences.
Methane is a significant contributor to global warming and is produced
by certain types of bacteria in oxygen-deprived environments - such as
those feeding on the organic waste in water-covered rice paddies.
The team says that if draining is combined with applying rice straw -
the stem and leaves left behind after harvesting - methane emissions
could be reduced by 7.6 million tonnes a year, representing around 30
per cent of global emissions from rice fields.
Rice straw is traditionally either burned between growing seasons or
ploughed back into the soil as a source or nutrients for the next
season's crop. When the field is reflooded, microorganisms feeding on
the rice straw generate methane. But if the straw is left to decompose
in the open air of a drained field during the fallow season, methane
emissions would be reduced, say the researchers, and the rice straw
could still supply some nutrients to the soil. |
| SciDev / Global Biogeochemical Cycles
May 20, 2009 |
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| New web tool Wolfram Alpha launches |
The much-heralded Wolfram Alpha computational knowledge engine has
finally launched. Feedback about the site is largely positive, although
some users have expressed frustration with persistent deficiencies.
The site differs from a regular search engine in that it processes
queries to return the actual answers, instead of returning a list of web
pages that may contain the result.
Wolfram Alpha's creator, British-born Stephen Wolfram, has claimed that,
thanks to 'algorithms and heuristics, lots of linguistic discovery and
linguistic curation, and some serious theoretical breakthroughs', the
tool is able to understand even complex human language to provide the
correct answer.
Feedback on the Wolfram Alpha blog appears positive in the main, and
many are heralding the site as the 'future of search'. The new web tool
can be accessed at http://www.wolframalpha.com. |
| VNU net UK
May 18, 2009 |
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| A Facebook profile can reveal the real you |
Judging a book by its cover may be unwise, but online profiles are fair
game, new research suggests. University students considered likeable by
people that met them in real life have been found to make a similar
impression on people who view their Facebook profiles.
For the study, psychologists at Tufts University in Medford,
Massachusetts recruited 37 university students, 18 of them women, to
come to the lab for a one-on-one chat with another study participant.
the team told the two to get to know one another by asking questions for
several minutes. However, one of each pair was actually a researcher
masquerading as a student. Afterwards the role-playing researchers, none
of whom were members of the team, rated each participant's likeability,
based on their tone of voice, how much they smiled, how much they
revealed about themselves, and other verbal and nonverbal factors.
Immediately afterward, the researchers downloaded the Facebook profile
of the volunteer and asked a panel of 10 students from another
university to rate the likeability of its owner. The Facebook pages that
earned the highest likeability rating were the most expressive, loaded
with pictures and wall posts, the researchers found. And these people
also tended to be rated as the most affable volunteers in person, being
assessed by the undercover researcher as being very animated and with
expressive body language. |
| New Scientist / Journal of Experimental Social Psychology
May 26, 2009 |
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