| Issue no. 28, 2009
Published: Aug 28, 2009
| Engineers call for 'artificial trees' to reduce CO2|
| New device will help ESA to monitor the Earth|
| How to turn seawater into jet fuel|
| Moon rock can be processed directly to produce oxygen|
| Bacteria make nanomagnets for navigating the oceans|
| Researchers crack WPA encryption in 60 seconds|
| Images reveal 'lost' Roman city|
|Engineers call for 'artificial trees' to reduce CO2
|Constructing a forest of 'artificial trees' is one of the most promising
technologies to remove CO2 from the atmosphere, according to a report
published by the Institution of Mechanical Engineers in the UK.
Most attempts to deal with climate change involve reducing emissions of
CO2. Yet even a global agreement to cut CO2 emission by 50% by 2050 may
not be enough to stop the planet's average temperature rising by 2 °C by
the end of the century. Geoengineering offers an alternative approach. A
new British report, 'Geoengineering – Giving us Time to Act?', looks at
different geoengineering options for tackling climate change.
The authors found that constructing fly-swat-shaped 'artificial trees'
is the most promising approach to reducing CO2. Such a tree would work
by letting air pass through into the structure and then catching the CO2
via a 'sorbant' material, such as sodium hydroxide. The CO2 is then
removed and buried underground in a similar manner to conventional
carbon capture and storage.
According to the report, constructing 100,000 such 'trees' would require
600 hectares of land but would be enough to remove the CO2 from the UK's
homes and transport system. The report also recommends coating buildings
with algae, which would absorb CO2 via photosynthesis. The authors state
that the algae can then be periodically harvested from building surfaces
and used as biofuel. The third recommendation is to make building
surfaces more reflective.
Aug 27, 2009
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|New device will help ESA to monitor the Earth
|Researchers at Queen's University in Northern Ireland have built an
instrument that could significantly improve the imaging of clouds from
space, leading to more accurate weather forecasts and climate models.
The electronic device will give meteorologists and climate scientists
access to previously undetectable thermal emissions from clouds, which
could reveal valuable information concerning the formation of rainfall
and the Earth's energy budget. The device will be used by the European
Space Agency (ESA) in a number of upcoming missions.
With the uncertainty surrounding the effect of clouds in climate models,
satellite instruments are playing an increasingly important role in
climate science. Space-borne remote sensing instruments, however, have
been limited by the fact that they can only detect either vertically or
horizontally polarized components of thermal emissions from gases in the
Earth's atmosphere – but not both at the same time.
The researchers have overcome this problem by designing an electronic
filter that can detect thermal emissions up to a very high frequency,
regardless of how they are polarized. The instrument, called a
dual-polarized Frequency Selective Surface Filter (SSF) is designed to
operate in the 250–360 GHz range but the researchers are also developing
an SSF to operate at 664 GHz – the highest dual-polarization detector
ever produced. One of the main advantages of SSF over alternative
detectors is that it is freestanding, which means that it can be
transferred between instruments in a range of different missions.
Aug 20, 2009
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|How to turn seawater into jet fuel
|Faced with global warming and potential oil shortages, the US navy is
experimenting with making jet fuel from seawater. Navy chemists have
processed seawater into unsaturated short-chain hydrocarbons that with
further refining could be made into kerosene-based jet fuel. But they
will have to find a clean energy source to power the reactions if the
end product is to be carbon neutral.
The process involves extracting CO2 dissolved in the water and combining
it with hydrogen (H) – obtained by splitting water molecules using
electricity – to make a hydrocarbon fuel. It uses a variant of a
chemical reaction called the Fischer-Tropsch process, which is used
commercially to produce a gasoline-like hydrocarbon fuel from syngas, a
mixture of carbon monoxide and hydrogen often derived from coal.
The navy team have been experimenting to find out how to steer the
CO2-producing process away from producing unwanted methane to produce
more of the hydrocarbons wanted. In the conventional Fischer-Tropsch
process, CO2 and H are heated in the presence of a catalyst to initiate
a complex chain of reactions that produce a mixture of methane, waxes
and liquid fuel compounds.
The researchers found that using the usual cobalt-based catalyst on
seawater-derived CO2 produced almost entirely methane gas. Switching to
an iron catalyst resulted in only 30% methane being produced, with the
remainder short-chain hydrocarbons that could be refined into jet fuel.
| New Scientist
Aug 18, 2009
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|Moon rock can be processed directly to produce oxygen
|British scientists have developed a reactor that can make oxygen from
Moon rock — a vital technology if plans to create a lunar base are to
take off. Ferrying oxygen to the Moon would be extremely expensive so
researchers are examining potentially cheaper ways to produce oxygen on
the Moon itself.
In 2005 NASA has offered a USD 250,000 prize to the first team to come
up with a piece of kit that could extract five kilograms of oxygen in
eight hours from some simulated Moon rock. Despite raising the value of
the prize pot to USD 1m in 2008 the prize remains unclaimed.
Now, researchers the University of Cambridge, UK have come up with a
potential solution by modifying an electrochemical process they invented
in 2000 to get metals and alloys from metal oxides. The process uses the
oxides — also found in Moon rocks — as a cathode, together with an anode
made of carbon.
In their tests, the researchers used a simulated lunar rock developed by
NASA. They anticipate that three reactors, each a metre high, would be
enough to generate a tonne of oxygen per year on the Moon. Three tonnes
of rock are needed to produce each tonne of oxygen, and in tests the
team saw almost 100% recovery of oxygen. To heat the reactor would need
just a small amount of power and the reactor itself can be thermally
insulated to lock heat in.
Aug 10, 2009
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|Bacteria make nanomagnets for navigating the oceans
|The genetic code for nano-sized biological magnets called 'magnetosomes'
has been cracked. Magnetosomes are created by oxygen-hating bacteria to
allow them to steer by the Earth's magnetic field, often to deep regions
of the ocean where there is less oxygen.
Now that the genes have been identified, they can be transferred to
other organisms or altered to produce customised magnetic particles for
practical applications. Already the particles have been extracted from
bacteria and injected into mice to improve imaging of cancers by MRI
scanners. They've also been used as nanomagnets in tests to detect
biological molecules such as the sugar-regulating hormone insulin.
Tadashi Matsunaga of the Tokyo University of Agriculture and Technology
in Japan discovered the core genes by comparing the genes of well-known
magnetic bacteria with those of a much more distant species called
Desulfovibrio magneticus strain RS-1. He identified three groups of
genes that seemed to be essential for making magnetosomes. The most
important cluster, called the 'magnetosome island', contains nine genes
instrumental in building the structures.
| New Scientist / Genome Research
Aug 12, 2009
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|Researchers crack WPA encryption in 60 seconds
|Japanese researchers say they have found a way to break the Wi-Fi
Protected Access (WPA) encryption system used in wireless routers, in
just 60 seconds. Toshihiro Ohigashi of Hiroshima University and Masakatu
Morii of Kobe University plan to explain their method at a technical
conference on 25 September in Hiroshima.
The attack potentially gives hackers a way to read encrypted traffic
sent between computers and certain types of routers that use the WPA
encryption system. The fact that WPA could be broken has been known for
some months, but the researchers have exploited a theoretical attack and
made it practical.
An earlier technique, developed by researchers Martin Beck and Erik
Tews, worked on a smaller range of WPA devices and took between 12 and
15 minutes. Both attacks work on WPA systems that use the Temporal Key
Integrity Protocol (TKIP) algorithm.
The WPA standard was originally designed as an interim encryption method
as Wi-Fi security was developing, and has long since been superseded by
WPA2. However, a fair bit of WPA with TKIP kit is still in use. Newer
WPA2 devices that use the stronger Advanced Encryption Standard
algorithm remain safe for now.
| VNUnet UK
Aug 27, 2009
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|Images reveal 'lost' Roman city
|Aerial photographs have revealed the streetplan of a lost Roman city
called Altinum, which some scholars regard as a forerunner of Venice.
The images reveal the remains of city walls, the street network,
dwellings, theatres and other structures. They also show a complex
network of rivers and canals, revealing how the people mastered the
marshy environment in what is now the lagoon of Venice.
Researchers at Padua University, Italy, made the first detailed
reconstruction of the city's topography and environmental setting. This
was assembled using visible and near-infrared aerial photographs of the
farmlands that currently cover the region, along with a computer model
of the local terrain.
The photos were taken during a severe drought in 2007, which made it
possible to pick up the presence of stones, bricks and other solid
structures beneath the surface. The authors note that Altinum is the
only large Roman city in northern Italy - and one of the few in Europe -
that has not been buried by medieval and modern cities.
The results show that the city was surrounded by rivers and canals,
including a large canal that cut through the centre of Altinum,
connecting it to the lagoon. Two gates or bridges were built into the
walls encircling the city, providing further evidence of how the city's
residents adapted to their marshy surroundings. The researchers were
also able to see harbour structures at the edge of the lagoon.
| BBC New / Science
Jul 31, 2009
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