Innovation and Technology Weekly – No. 27, 2009

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Issue 27, 2009

This week's headlines:

MIT discovery brings quantum information network step closer
July 28, 2009

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.

Full story: ScienceDaily / American Physical Society / Physical Review Letters Back to top

Three-in-one oven could ease energy needs in developing world
July 29, 2009

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.

Full story: Back to top

Wall 'could stop desert spread'
July 24, 2009

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.

Full story: BBC News Back to top

Scientists asked to create Earth systems research plan
July 28, 2009

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.

Full story: SciDev Back to top

Nanoscale light source can change its colour
July 28, 2009

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.

Full story: PhysicsWorld Back to top

Glass leaf 'sweats' to generate electricity
July 30, 2009

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.

Full story: New Scientist / Applied Physics Letters Back to top

Measuring emotion in cyberspace
July 28, 2009

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.

Full story: Scientific American / Journal of Happiness Studies Back to top

Researchers to zero in on lost tomb of Genghis Khan
July 30, 2009

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.

Full story: Daily Galaxy / University of California Back to top