Innovation and Technology Weekly – No. 32, 2008

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Issue 32, 2008

This week's headlines:

Computer circuit builds itself
October 15, 2008

A team of physicists at Philips Research Laboratories in Eindhoven, the Netherlands has developed an integrated circuit that can build itself. The work is an important step towards its ultimate goal - a self-assembling computer.

To make a circuit that is truly self-assembling, physicists would need to get insulators, conducting electrodes and semiconductor transistors to all link to each other automatically - something that is still a long way away. But the Philips team has made an important step. They took a long organic molecule with mobile electrons, called quinquethiophene, that behaves like a semiconductor and attached it to a long carbon chain with a silicon group at the end, which acts as an anchor.

The researchers then dunked a circuit board with preprinted electrodes into a solution of their new molecules. The molecules hooked on to an insulating layer between the electrodes, forming bridges from one electrode to the next. It took billions to make the connection, but they were tightly packed enough that a current could flow across them.

Full story: Nature Back to top

'Stamp' method brings bendy, transparent solar cells
October 09, 2008

Imagine solar cells that are flexible enough to be rolled up like a sheet of paper or so transparent that they can be hung over a window. Such solar cells are a step closer now that researchers at the University of Illinois and Northwestern University have devised a new method for printing thin wafers of silicon onto many other types of material.

They liken their method to the way a rubber stamp transfers ink from a pad to paper. First they etch a striped pattern onto a wafer of crystalline-silicon (the 'pad') before lifting the resulting segments (the 'ink') with a soft piece of polymer (the 'stamp'). Then they push the polymer onto the desired substrate (the 'paper') to print on the segments. Finally they evaporate metal onto the back of the material and etch it to leave electrodes running down the sides.

The benefit of this stamp method is that a wide variety of substrate materials, including flexible plastics, can be used. In tests, the new cells had a solar-energy conversion efficiency of 7.2% - significantly under commercial devices, which operate at about 18% - though were flexible enough to be rolled around a pencil. Another advantage of the US team's method is that the cells can be printed thinly or in sparse arrays so that they are partially transparent, which means they could, for example, be fixed over windows.

Full story: Physics World / Nature Materials Back to top

Success for plants' pest control
October 07, 2008

Researchers at Lancaster University have developed a potential new method of making plants significantly more resistant to pests. They say their method could greatly reduce pesticide use.

Until now attempts at creating pest- resistant crops involved GM technology. This method uses a chemical that is naturally produced by plants - jasmonic acid. Researchers have found that plants grown from seeds first dipped in the acid are considerably more resistant to pests. The effect is to boost the plant's own defences.

The best results were on tomato plants, where attacks by Red Spider Mites were reduced by 80%, aphid attack was reduced by 60% and caterpillar damage was down by a third. Good results were also obtained on maize, where caterpillar damage was reduced by 38%, sweet pepper where aphid attacks were reduced by 70%, and caterpillar damage to wheat was reduced by 65%.

Full story: BBC News Back to top

Newly discovered fungus strips pollutants from oil
October 08, 2008

A humble fungus could help oil companies clean up their fuel to meet tightening emissions standards. The fungus, recently discovered in Iran, grows naturally in crude oil and removes the sulphur and nitrogen compounds that lead to acid rain and air pollution.

Worldwide, government are imposing increasingly severe limits on how much of those compounds fuels can contain. Oil producers are searching for more efficient ways to strip sulphur and nitrogen from their products. The standard way to 'desulphurise' crude oil involves reacting it with hydrogen at temperatures of 455°C and up to 204 times atmospheric pressure. It achieves less than perfect results.

Micro-organisms able to metabolise sulphur and nitrogen have the potential to achieve the same endpoint under more normal conditions. In recent years a number of researchers have isolated desulphurising bacteria. But researchers at the Sharif University of Technology in Tehran, Iran, have now discovered and isolated a fungus that appears able to remove sulphur from oil with greater efficiency. The Stachybotrys fungus removed 76% of sulphur compounds in just 3 days, a figure only one bacteria could match over the full 6 days.

Full story: New Scientist / Industrial & Engineering Chemistry Research Back to top

Gecko-like glue is said to be stickiest yet
October 09, 2008

A new type of dry glue designed to mimic gecko feet is 10 times stickier than the gravity-defying lizards, and three times stickier than other gecko-inspired glues, according to researchers at the University of Dayton.

A 2.5-cm square of the adhesive can support the weight of a 100-kg man climbing up a vertical surface, but it can be easily lifted and reapplied. Aside from helping people walk up walls, the glue could be used in electrical components without the need for soldering. And because it is dry, it could be used at very low temperatures as in space, where more conventional glues lose their grip.

Like other gecko-inspired glues, the new glue uses a carpet of carbon nanotubes, thin filaments of carbon molecules. But attached to the ends of these filaments are curly strands of carbon that expand the surface area of the glue's gripping action. This design matches the structure of real gecko feet, which have microscopic hairs that branch off in different directions.

Full story: Reuters / Science Back to top

Giant lens could clean up dusty moon sites
October 15, 2008

When it comes to keeping moon dust at bay, nothing beats a little sunshine. So says a NASA team studying methods to protect a future moon base from the fine powder on the lunar surface. The dust is easily disturbed and highly abrasive. It could damage equipment and, if it gets into inhabited areas, astronauts' lungs.

The answer, says study leader Paul Hintze of the Kennedy Space Center in Florida, is a 1-metre-wide lens that focuses sunlight to melt and fuse the dust. In tests on Earth, a solar concentrator heated the soil to 1350 °C, forming a solid crust 6 millimetres deep within 3 minutes.

The team say the technique could be used to create landing and launch pads for spacecraft as well as roads for lunar vehicles, to cut down the amount of dust kicked up.

Full story: New Scientist Back to top

Monkeys move paralysed muscles with their minds
October 15, 2008

A monkey's paralysed wrist can be moved and controlled by electrical signals artificially routed from its brain, according to scientists who say that their experiment is a step towards helping paralysed people to regain the use of their limbs.

Previously, scientists have been able to train monkeys to move robotic arms using signals routed from electrodes in their brains. This involved decoding the activity of tens of neurons at a time to replicate actions such as grasping, and required considerable computing power. Now, researchers at the University of Washington have used similar signals to deliver direct electrical stimulation from just one neuron to a paralysed muscle.

They first implanted a number of electrodes in the motor cortex of two macaque monkeys. Each electrode picked up signals from a single neuron, and those signals routed through an external circuit to a computer. The neuronal signals controlled a cursor on a screen, and the monkeys were trained to move the cursor using only their brain activity. The scientists then temporarily paralysed the monkeys' wrist muscles using a local anaesthetic. They re-routed the signals from the electrodes to deliver electrical stimulation to the wrist muscles, and found that the monkeys could control their previously paralysed limbs using the same brain activity. The monkeys learnt to do this in less than an hour.

Full story: Nature Back to top

'Transparent cockpit' removes car blind spots
October 08, 2008

No matter how clean your car's windshield, the view from the driver's seat is less than perfect. Solid features such as dashboard and doors can conceal road hazards such as other vehicles and pedestrians.

Now a team of engineers at the University of Tokyo has come up with a way to make those solid features 'disappear', at least from the driver's point of view, without modifying them in any way. A pair of stereo cameras mounted on the passenger-side wing mirror capture scenery hidden from the driver by the dashboard and the solid parts of doors.

A headset worn by the driver projects the cameras' output onto the solid features, displaying a clear view of what hides behind them as if they were transparent. To make the car appear transparent to the driver, video output from the headset is projected onto a retro-reflective surface covering the opaque parts of the interior. This surface directs any light that hits it straight back along its path and produces vivid video images.

To enhance the illusion of transparency, the projected images must be scaled correctly. The system does this by using stereo cameras to judge the distance to objects in view, much the way humans do. The head position of the driver is also taken into account, using movement sensors mounted on the headset projector. The result is a true-to-life view of the outside, as if the opaque parts of the car weren't there.

Full story: New Scientist Back to top