Innovation and Technology Weekly – No. 11, 2011

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Issue 11, 2011

This week's headlines:

Closing old atom plants poses safety challenge: IAEA
March 24, 2011

The closing of aging nuclear reactors is expected to peak in 2020-30, posing a major challenge in terms of safety and the environment. A draft report, submitted to member states of the International Atomic Energy Agency (IAEA) shortly before Japan's nuclear crisis erupted this month, said the global nuclear sector maintained a high level of safety performance in 2010. But, it warned, 'in some cases, plans for nuclear power program development moved faster than the establishment of the necessary regulatory and safety infrastructure and capacity'.

The report did not name any countries. It invited comment from the IAEA's 151 member states by mid-April, before a final version would be issued. The document, Nuclear Safety Review for the Year 2010, may attract wider interest and scrutiny in light of events at Japan's Fukushima nuclear power plant.

Japan's nuclear emergency has sparked debate about the IAEA's role in helping to ensure the safe use of nuclear power and to prevent accidents which can have cross-border effects. IAEA Director General Yukiya Amano this week said international safety standards needed to be strengthened but the agency was not a 'nuclear safety watchdog', stressing safety was the responsibility of individual countries.

The safety report for last year noted that of the 441 reactors now in operation around the world, many were built in the 1970s and 1980s, with an average lifespan of about 35 years. The Fukushima plant also dates back to the 1970s. 'Their decommissioning peak will occur from 2020 to 2030 which will present a major managerial, technological, safety and environmental challenge to those states engaged in nuclear decommissioning,' it said.

Full story: Reuters Back to top

Thorium reactors could rescue nuclear power
March 23, 2011

'It is not difficult to conceive of an entire planet powered by thorium,' wrote Kirk Sorensen on his blog Energy From Thorium in 2006. Some would contest this bold claim, but given the crisis at the Fukushima Daiichi nuclear power plant in Japan, the energy source Sorensen advocates has been thrust into the spotlight.

Sorenson and others propose building reactors that use a naturally occurring element called thorium as the main starting material, instead of uranium or plutonium. Though the technology is far from fully developed and very different to conventional plants based on solid uranium and plutonium fuel, advocates say it would be immune to the problems that have plagued the Fukushima reactors.

At the heart of a liquid fluoride thorium reactor (LFTR) is a chamber filled with thorium dissolved in a molten salt such as lithium fluoride at several hundred degrees Celsius. Thorium itself is barely radioactive, so a small amount of uranium-233 is added to kick-start nuclear reactions. Like U-235, it is radioactive and so fissions, releasing heat as well as neutrons. These hit thorium atoms, transforming them into more U-233 and producing heat in the process. The U-233 in turn fissions to produce more neutrons.

The fuel cools as it passes through a heat exchanger containing more molten salt, and this heated salt can then be used to drive turbines and generate electricity. Without water as a coolant, there is a much lower risk of explosions. A liquid fuel also reduces the volume of radioactive waste. Another advantage is that fluoride salts are not flammable. Moreover, thorium is globally much more abundant than U-235.

Full story: New Scientist Back to top

Making sperm in a Petri dish
March 23, 2011

A sperm is a complex machine. Its whipping tail, the spiralling mitochondria of its midsection, a head specialised to plow through the outer membrane of an egg-all are the product of a long, highly specialised development process in the testes. For nearly a century, researchers have failed to recreate the process in the lab. But now they have come closer than ever before, growing testes in a dish and using the sperm to sire a litter of baby mice. The work, say experts, holds promise for improving in vitro fertilization (IVF) and artificial insemination techniques in humans.

In the new study, researchers at Yokohama City University in Japan removed testes from baby mice that were 2 or 3 days old, ensuring that the rodents did not already have mature sperm. They placed these in a petri dish containing a specialised culture medium that included a component called KSR, which is often used for culturing embryonic stem cells. Then they let the testes grow up.

After about a month, the researchers saw that the testes looked relatively normal and were producing sperm, which had been engineered so that they turned fluorescent green once they were mature. When they extracted the sperm and artificially inseminated female mice, healthy pups were born. The cultured testes kept making sperm for two more months. Using the same method, the researchers were even able to produce sperm from young testes that had been frozen for a month.

Full story: Science Now / Nature Back to top

Mosquito needle helps take sting out of injections
March 24, 2011

A motorised, harpoon-like needle sounds painful, but in fact hurts far less than a regular injection because it resembles a mosquito's mouth parts. Researchers at Kansai University in Osaka, Japan, have developed a needle that mimics a mosquito's proboscis, which is serrated and barely touches the skin so you don't feel the initial bite. A smooth hypodermic, on the other hand, leaves a lot of metal in contact with the skin, stimulating the nerves and causing pain. The team hope their design could help diabetic people who have to take blood samples.

Etched from silicon, the needle imitates three of the creature's seven mobile mouthparts: the two serrated maxillae and the tubular labrum. Each of these parts is driven by tiny motors based on lead zirconium titanate (PZT) - a piezoelectric crystal that expands very slightly when you apply an alternating voltage. The vibrations of the crystal can be used as a simple motor to control how the needle enters the skin.

The sections of the needle break the skin in the same sequence as they do with a mosquito, vibrating at about 15 hertz to ease it into the skin - as observed in mosquitoes under high-speed video microscopes. The needle was tested on volunteers, who agree that the pain is much reduced but lasts longer than with a conventional syringe. The researchers think that by mimicking more of the creature's mouthparts they'll be able to reduce that dull pain.

Full story: New Scientist Back to top

Seeing below the surface
March 24, 2011

In recent years, many airplane manufacturers have started building their planes from advanced composite materials, which consist of high-strength fibres, such as carbon or glass, embedded in a plastic or metal matrix. Such materials are stronger and more lightweight than aluminium, but they are also more difficult to inspect for damage, because their surfaces usually don't reveal underlying problems.

Now, researchers at MIT have devised a new way to detect that internal damage, using a simple handheld device and heat-sensitive camera. Their approach also requires engineering the composite materials to include carbon nanotubes, which generate the heat necessary for the test. Their approach could allow airlines to inspect their planes much more quickly, the researchers say.

Advanced composite materials are commonly found not only in aircraft, but also cars, bridges and wind-turbine blades. One method that inspectors now use to reveal damage in advanced composite materials is infrared thermography, which detects infrared radiation emitted when the surface is heated. In an advanced composite material, any cracks or delamination will redirect the flow of heat. That abnormal flow pattern can be seen with a heat-sensitive camera.

This is effective but cumbersome because it requires large heaters to be placed next to the surface. With the new approach, carbon nanotubes are incorporated into the composite material. When a small electric current is applied to the surface, the nanotubes heat up, which eliminates the need for any external heat source. The inspector can see the damage with a thermographic camera or goggles.

Full story: MIT / Nanotechnology Back to top

Stock trades to exploit speed of light, says researcher
March 23, 2011

Financial institutions may soon change what they trade or where they do their trading because of the speed of light. 'High-frequency trading' carried out by computers often depends on differing prices of a financial instrument in two geographically-separated markets. Exactly how far the signals have to go can make a difference in such trades.

Alexander Wissner-Gross of Harvard University told the American Physical Society meeting that financial institutions are looking at ways to exploit the light-speed trick. He said that the latencies - essentially, the time delay for a signal to wing its way from one global financial centre to another - advantaged some locations for some trades and different locations for others.

There is a vast market for ever-faster fibre-optic cables to try to physically 'get there faster' but Dr Wissner-Gross said that the purely technological approach to gaining an advantage was reaching a limit. Trades now travel at nearly 90% of the ultimate speed limit set by physics, the speed of light in the cables.

His first solution considered the various latencies in global fibre-optic links and mapped out where the optimal points for financial transactions to originate - midway between two major financial hubs to maximise the chance of 'buying low' in one place and 'selling high' in another. That of course resulted in a number of ideal locations in all corners of the globe, including the oceans. But wholesale relocation of operations does not immediately appeal to many firms.

Because there is a clear, physical advantage to the approach, Wissner-Gross said that the first firm to try to exploit the effect will be at significant competitive advantage - until more firms follow suit. That means that out-of-the-way places - at high latitudes or mid-ocean island chains - could in time turn into global financial centres.

Full story: BBC News Back to top

Engraved plastic panel casts image in light and shade
March 23, 2011

Shine a light through a wine glass and you will see refracted slivers of brightness overlaying the glass's shadow. It is complex versions of these bright patterns, called caustics, that are now being exploited to reproduce a photographic image.

Tim Weyrich, a researcher at University College London, worked with researchers at Disney Research Zurich, Switzerland, and Princeton University to manufacture Plexiglass slabs that produce caustics in the shape of a predefined image. Each 10-centimetre-square slab contains over 1000 tiny curved patches that act like lenses, shaping the light into fuzzy elliptical patches that together make up the image.

The team determines the exact pattern of patches required by looking at the energy distribution of a greyscale image: brighter regions have more energy, while darker ones have less. They then work out the collection of curved patches that reproduces this energy distribution, and so replicates the image. If that sounds tricky, manufacturing the required surface is even harder. Each curved patch has to be painstakingly carved out by a computer-controlled mill, and producing a single slab can take up to three days. Weyrich hopes this could eventually be speeded up.

The team have also applied the techniques to reflected light by manufacturing metallic surfaces that generate highlights in the shape of a desired image. These could be used as a security feature similar to the holograms now used on credit cards.

Full story: New Scientist Back to top