Issue no. 27, 2009
Published: Jul 31, 2009 |
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 MIT discovery brings quantum information network step closer |
| Three-in-one oven could ease energy needs in developing world |
| Wall 'could stop desert spread' |
| Scientists asked to create Earth systems research plan |
| Nanoscale light source can change its colour |
| Glass leaf 'sweats' to generate electricity |
| Measuring emotion in cyberspace |
| Researchers to zero in on lost tomb of Genghis Khan |
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| MIT discovery brings quantum information network step closer |
Scientists at MIT have figured out a key step toward the design of
quantum information networks.
A quantum network - in which memory devices that store quantum states
are interconnected with quantum information processing devices - is a
prototype for designing a quantum internet. One path to making a quantum
network is to map a light pulse onto nodes in a material system.
However, it is difficult to generate a signal that heralds that the
pulse has been successfully caught. Quantum systems follow Heisenberg's
rule that observing an event may destroy it, so the system has to emit
just the right kind of herald pulse so as not to erase the data.
Now, researchers at MIT have demonstrated an atomic quantum memory that
heralds the successful storage of a light beam in a cold atom gas. The
atomic-ensemble memory can receive an arbitrary polarization state of an
incoming photon, called a polarisation qubit, announce successful
storage of the qubit, and later regenerate another photon with the same
polarisation state. The herald signal only announces the fact the pulse
has been captured, not details of the polarisation, so the quantum
information is preserved. |
| ScienceDaily / American Physical Society / Physical Review Letters
Jul 28, 2009 |
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| Three-in-one oven could ease energy needs in developing world |
A combined combustion oven and refrigerator that can also harness
electricity from its vibrations is now undergoing field trials in the UK
and Nepal. The versatile appliance has been developed over the past two
years through a UK research collaboration led by the University of
Nottingham. With its cheap production costs and variety of functions,
the new generator could become an affordable and sustainable energy
technology for communities in the developing world1.
Underpinning the electricity generator is a two-step energy conversion
from heat to sound to electricity, which takes place inside a gas-filled
pipe. A fire at one end of the pipe creates a temperature gradient,
which triggers acoustic waves as gas moves from hot to cold regions -
much like a singing kettle as the water reaches boiling point. These
sound waves can then be harnessed by a linear alternator, which converts
mechanical energy into electrical electricity in the reverse process to
an electric motor.
Some of the pipe's vibrations can also be passed into another
thermoacoustic engine, which works in reverse to generate a cooling
effect. Finally, the heat from the burning wood or other available
biomass can also be used for cooking. These three functions can be run
simultaneously to provide the users with a combined stove, refrigerator
and electricity generator. |
| Physicsworld.com
Jul 29, 2009 |
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| Wall 'could stop desert spread' |
A plan to build a 6,000km-long wall across the Sahara Desert to stop the
spread of the desert has been outlined. The barrier - formed by
solidifying sand dunes - would stretch from Mauritania in the west of
Africa to Djibouti in the east. The plan was put forward by architect
Magnus Larsson at the TED Global conference in Oxford.
North African nations have promoted the idea of planting trees to form a
Great Green Belt to prevent the spread of the sand. A similar proposal -
known as the Green Wall of China - has also been proposed to stop the
spread of the Gobi Desert.
The architect's proposed wall across the desert would be a complement
to, rather than a replacement, of the Great Green Belt proposal, and
provide physical support for the trees. The wall would effectively be
made by 'freezing' the shifting sand dunes, turning them into sandstone.
The sand grains would be bound together using a bacterium called
Bacillus pasteurii commonly found in wetlands, which chemically produces
calcite - a kind of natural cement. |
| BBC News
Jul 24, 2009 |
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| Scientists asked to create Earth systems research plan |
Scientists around the world are being challenged to find the most
pressing research questions linked to global environmental change in the
next decade. Everyone is invited to participate in the online research
project, particularly researchers early in their careers and those with
an interest in Earth sciences and the environment.
The consultation, which is run by the France-based International Council
for Science (ICSU) in cooperation with the International Social Science
Council, has a closing date of 15 August. Participants in the 'Earth
System Visioning' project are asked to identify the most important
research questions and vote on the contributions of others in a bid to
shape the research agenda in Earth systems research.
ICSU hopes to harness the potential of communication technologies to use
'the widest possible net' to capture the opinion of geographically
dispersed scientists across a wide range of disciplines, they add. It
wants as many people as possible to help shape the relevance of the
outcomes, so the results belong to the broader international community. |
| SciDev
Jul 28, 2009 |
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| Nanoscale light source can change its colour |
An international collaboration claims to have made the first tuneable
nanoscale light source that is driven by free electrons.
Light is created by directing a beam of electrons through a tiny
aperture that has been drilled into a stack of alternating gold and
silicon-dioxide layers. Interaction between the electron beam and the
alternating layers generates visible and infrared light emission. The
device resembles a free-electron laser in which a beam of electrons
passes through an alternating magnetic field - causing the electrons to
'wiggle' and emit light.
The invention could lead to an on-chip light source for nanophotonic
circuits, according to the partnership, which involves researchers at
the University of Southampton, UK, National Taiwan University and
theorists at CSIC in Madrid, Spain. Next-generation displays could also
benefit from a tuneable light source. Switching to this type of device
could eliminate the need for separate pixels that deliver different
colours of light such as red, green and blue. |
| PhysicsWorld
Jul 28, 2009 |
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| Glass leaf 'sweats' to generate electricity |
Artificial photosynthesis has yet to be cracked, but electrical
engineers from the University of California, the University of Michigan
and MIT think that synthetic leaves could be used to generate
electricity in a different way - by sweating.
Natural leaves constantly lose water through transpiration, which draws
water from the roots to the very top of even the tallest trees. The new
synthetic leaves also lose water through evaporation to create that
mechanical water pump effect, and use it to generate power. The
researchers built their leaves from glass wafers shot through with a
branching network of tiny water-filled channels arranged like the veins
of a leaf. The smaller channels extend to the edge of the plate and have
open ends that allow water to evaporate, drawing fluid along the leaf's
central stem at a rate of 1.5 centimetres per second.
The researchers added metal plates to the walls of the central stem and
connected them to a circuit. The charged plates and the water within the
stem create a sandwich of two conducting layers separated by an
insulating layer - in effect, a capacitor. The leaf is transformed into
a source of power by periodically interrupting the water flowing into
the leaf with air bubbles. Thanks to the different electrical properties
of air and water, every time a bubble passes between the plates the
capacitance of the device changes and a small electric current is
generated, which passes to an external circuit where it's used to pump
up the voltage on a storage capacitor. |
| New Scientist / Applied Physics Letters
Jul 30, 2009 |
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| Measuring emotion in cyberspace |
The mood of cyberspace has been probed by researchers who have found
that US Election Day, Nov. 4, 2008, was the happiest day in the past
four years among bloggers, while the day Michael Jackson died was one of
their unhappiest. Insights into whether individuals are happy, sad,
proud or mad are becoming increasingly available on the internet. And
the blog can be read as the new diary. This growing public dataset is a
treasure trove for researchers struggling to find a better way to
measure happiness, according to scientist at the University of Vermont.
By analyzing the content of writers' blogs the researchers could observe
people in a more natural environment than previous happiness studies,
which typically involved questionnaires filled with self-reported
feelings that can be misrepresented or recalled inaccurately. While blog
writers tend to be younger and more educated than the general
population, previous studies have shown that they split gender evenly
and span the races.
The researchers analysed the words in nearly 10 million first-person
sentences that contained the word 'feel'-all posted over the last four
years in 2.3 million worldwide blogs. An overall score ranging from 1 to
9 was applied to each sentence, based on a weighted average of the
perceived happiness of each key word. The researchers have also applied
their methods to song lyrics, speeches and Twitter messages. The latter
provides a more immediate measure of happiness patterns, they say. |
| Scientific American / Journal of Happiness Studies
Jul 28, 2009 |
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| Researchers to zero in on lost tomb of Genghis Khan |
Eight hundred years after the death of Genghis Khan, ruler of the Mongol
Empire, the largest contiguous empire in history, scientists are
searching to locate his lost tomb using advanced visualization
technologies.
After his death in 1227, Genghis Khan's body was returned to Mongolia to
his birthplace in Khentii Aimag, where many assume he is buried
somewhere close to the Onon River and the Burkhan Khaldun mountain
range. According to legend, the funeral escort executed anyone crossing
their path to conceal his burial place, and that a river was diverted
over his grave to make it impossible to find. The area around his tomb
was deemed forbidden by the emperor's guards.
Now researchers are hoping to use advanced visualization and analytical
technologies available at the California Institute for
Telecommunications and Information Technology to pinpoint Khan's tomb
and conduct a non-invasive archaeological analysis of the area where he
is believed to be buried. |
| Daily Galaxy / University of California
Jul 30, 2009 |
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