Catalyst improves prospects for fuel cells

Chemistry WorldJon Cartwright

Published in Chemistry World, 23 Sep 2010

Chemists in the US have developed a new catalyst that could help in a key reaction used to generate hydrogen for fuel cells.

The so-called water-gas shift (WGS) reaction is often used in industry to help purify the hydrogen that is generated as a by-product in the reforming of natural gas. In the reaction, residual carbon monoxide in the hydrogen is combined with steam in the presence of a catalyst to produce hydrogen and carbon dioxide. The process purifies the hydrogen gas to a level where it can be used in fuel cells. […]

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Picture this

ProspectJon Cartwright

Published in Prospect, 25 Aug 2010

Never let it be said that rubbish collectors aren’t some of the bravest people on Earth. I don’t mean the nice people who empty your bin, but the experts who scour the forgotten fields of past conflicts, first with sniffer dogs, then metal detectors, and finally with long-bladed knives, stretched out on their stomachs while nervously probing the ground ahead.

Their usual name is minesweepers, but their profession would be more accurately categorised as waste removal. The latest UN figures estimate that there are more than 100m landmines in the world, which kill some 5,000 people every year. Yet minesweepers spend 90 per cent of their time digging up pieces of harmless junk on the off-chance it could cause an explosion. “You get a signal from your metal detector, and you don’t know what it is,” says Phil Halford, who works for the Mines Advisory Group (MAG). He has spent his working life clearing explosives everywhere from Afghanistan to Sudan. “It could be a piece of tin, a piece of scrap, whatever. The biggest problem is false-positive detection.”

But now an international group of scientists has come up with a solution. Called RASCAN, their device uses radar to not only spot a buried object, but to pick out a rough image. It could help minesweepers across the world skip over rubbish and focus on their real job. Colin Windsor, a retired British nuclear physicist working on the project, estimates that this could at least double the detection rate. […]

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Photons meet with three-way split

NatureJon Cartwright

Published in Nature, 28 Jul 2010

A single photon can now be split into three, thanks to the work of an international team of physicists. The achievement could open up new avenues in the field of quantum information.

The ability to split photons may not sound as extraordinary as other achievements in quantum physics, but for decades it has proved crucial to the success of many experiments. Often researchers need to know that photons are emitted at precisely the same time and are in phase with each other, and this is almost impossible if the photons come from separate sources. […]

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Quantum mechanics flummoxes physicists again

NatureJon Cartwright

Published in Nature, 22 Jul 2010

If you ever want to get your head around the riddle that is quantum mechanics, look no further than the double-slit experiment. This shows, with perfect simplicity, how just watching a wave or a particle can change its behaviour. The idea is so unpalatable to physicists that they have spent decades trying to find new ways to test it. The latest such attempt, by physicists in Europe and Canada, used a three-slit version — but quantum mechanics won out again.

In the standard double-slit experiment, a wide screen is shielded from an electron gun by a wall containing two separated slits. If the electron gun is fired with one slit closed, a mound of electrons forms on the screen beyond the open slit, trailing off to the left and right — the sort of behaviour expected for particles. If the gun is fired when both slits are open, however, electrons stack along the screen in comb-like divisions. This illustrates the electrons interfering with each other — the hallmark of wave behaviour. […]

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The scourge of inequality

VenueJon Cartwright

Published in Venue, 21 Jul 2010

All things being equal really does make all things better, says Jon Cartwright

Few would argue against having a longer life. But here’s a quick test of your mortal knowledge: at which periods in the twentieth century has British life expectancy risen fastest? Perhaps after the surge of vaccine discoveries in the 1920s? Or perhaps after the introduction of the National Health Service in 1948?

Wrong. In fact, life expectancy rose fastest — for civilians, at least — during the two world wars. No, I’m not kidding. The reason why people started to live longer is simple: society became far more equal. Almost everyone was employed and fuelled by a sense of camaraderie. Thanks to the government, incomes of the poorest shot up by some 10 per cent, while incomes of the middle class fell by almost as much. You can rave about medical breakthroughs all you like, but in developed countries income equality is the surest route to a longer life. (more…)

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Fibres form all-in-one speaker and microphone

Physics WorldJon Cartwright

Published in Physics World, 16 Jul 2010

Researchers at the Massachusetts Institute of Technology (MIT) in the US have created a new generation of fibres that, they claim, can both detect and produce sound. The fibres, which contain a tree-ring structure of piezoelectrics, electrodes and polymers, could have a range of applications that include medical imagers and microphones weaved into clothing.

Conventional fibre optics, which transmit light across their length through a process of total internal reflection, have become crucial for modern industry. Without them, we would have none of the long-distance, high-bandwidth communications that we take for granted today. […]

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Inquiry relights tensions in South African astronomy

Physics WorldJon Cartwright

Published in Physics World, 15 Jun 2010

A new inquiry into the management of one of South Africa’s biggest science facilities is to be held by the science and technology committee of the country’s parliament. The inquiry will look into the South African Large Telescope (SALT), although there is confusion over the specific allegations and who has levelled them.

This year has been a turbulent time for the South African Astronomical Observatory (SAAO), which operates SALT. In March, the director of the SAAO, Phil Charles, was reinstated to his post after having been cleared of allegations by the National Research Foundation (NRF) of leaking confidential information on telescope and management proposals. […]

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Imaging technique sees conversion of biomass to sugar

Chemistry WorldJon Cartwright

Published in Chemistry World, 5 Jul 2010

Researchers in the US have demonstrated an imaging technique for studying the conversion of biomass into fuel-friendly sugars. The technique, called stimulated Raman scattering (SRS) microscopy, is better than others because it can give quantitative readings of the species present.

Biomass is often cited as a renewable source of energy that could reduce our dependence on fossil fuels. Its two most important species are lignins and polysaccharides, which can be broken down into simple sugars for fermentation into ethanol. However, with many different types of chemical bonds, and with very complex structures, lignins don’t take to decomposition easily. Scientists try to do it with enzymes, but to understand the most effective methods they need analytical tools to study the process. […]

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Carbon nanotubes boost battery power

Chemistry WorldJon Cartwright

Published in Chemistry World, 20 Jun 2010

Researchers in the US claim to have created electrodes from carbon nanotubes that can make lithium-ion batteries some ten times more powerful than conventional models. Such batteries, they say, could one day be used for power-hungry applications, such as hybrid vehicles and renewable energy sources.

One challenge in the field of energy storage is to create devices that combine the high capacity of batteries with the high power delivery of capacitors. If batteries are the starting point, the trick is to improve the speed at which ions flow into electrodes. During the discharge of a battery, ions flow from within the anode to the electrolyte and into the cathode, thereby generating the current – so speeding this process up is key to creating high power delivery. […]

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‘Dark pulse laser’ could improve telecoms

Physics WorldJon Cartwright

Published in Physics World, 16 Jun 2010

A new type of laser that emits “dark” pulses could provide better signals for telecommunications, according to physicists in the US who have created the device. The dark pulses, which consist of intensity dips in an otherwise continuous beam of laser light, are effectively the opposite of the bright bursts in a normal pulsed laser.

“The laser emits a brief pulse of darkness, if you will,” explains one of the researchers Richard Mirin, who is at the National Institute of Standards and Technology (NIST) in Boulder, Colorado. “And so you can think of it as a continuous-wave laser that has a really fast shutter in front of it.” […]

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