News & Current Affairs

September 10, 2008

Fusion power seeks super steels

Fusion power seeks super steels

Jet (EFDA)

The JET lab has helped pioneer fusion

Scientists say an understanding of how the Twin Towers collapsed will help them develop the materials needed to build fusion reactors.

New research shows how steel will fail at high temperatures because of the magnetic properties of the metal.

The New York buildings fell when their steel backbones lost strength in the fires that followed the plane impacts.

Dr Sergei Dudarev told the British Association Science Festival that improved steels were now being sought.

The principal scientist at the United Kingdom Atomic Energy Authority (UKAEA) said one of the first applications for these better performing metals would be in the wall linings of fusion reactors where temperatures would be in a similar range to those experienced in the Twin Towers’ fires.

‘Not melting’

The key advance is the understanding that, at high temperatures, tiny irregularities in a steel’s structure can disrupt its internal magnetic fields, making the rigid metal soft.

“Steels melt at about 1,150C (2,102F), but lose strength at much lower temperatures,” explained Dr Sergei Dudarev, principal scientist at the United Kingdom Atomic Energy Authority (UKAEA).

Atoms in steel (UKAEA)

Iron atoms in steel: Black balls show irregularities that disrupt magnetic fields, weakening steel

At room temperature, the magnetic fields between iron atoms remain regular, but when heated, these fields are altered allowing the atoms to slide past each other, weakening the steel.

“[The steel] becomes very soft. It is not melting but the effect is the same,” said Dr Dudarev.

He said blacksmiths had exploited this property for hundreds of years – it allows iron to become pliable at temperatures much lower than its melting point.

The peak in this pliability is at 911.5C, but begins at much lower temperatures, at around 500C (932F) – a temperature often reached during building fires.

The steel backbone of the Twin Towers was probably exposed to temperatures close to this, when insulating panels – meant to protect the buildings’ structural frame – were dislodged by the impacts of the hijacked planes.

The roaring fire mid-way up the building heated the steel struts, and once temperatures rose above 500C the structure became elastic, and collapsed under the force of the floors above.

Tuning up

The interest of Dr Dudarev and the UKAEA is to find steels that can withstand the intense heat of being inside a a fusion reactor.

UKAEA has helped pioneer fusion power – deriving energy by forcing together atomic nuclei – at Europe’s JET lab in Oxfordshire; and is now assisting the development work on the world first large-scale experimental reactor known as Iter.

The extended periods over which Iter will run means the reactor must have robust materials built into the vessel where the fusion reactions will occur.

Dr Dudarev said it should be possible to tune the properties of suitable new steels by adding a mix of other elements.

“We need to look at the magnetic properties of steel, [and] vary their chemical composition in a systematic way in order to get rid of this behaviour,” he suggests.

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September 9, 2008

Hugging benefits fractious chimps

Hugging benefits fractious chimps

Chimps at Chester Zoo (Orlaith Fraser)

The consoling arm of a good friend

If you have just had a big falling out with a colleague, there is nothing better than the comforting and consoling arm of a good friend.

Chimps, it seems, feel the same way, according to a study at Chester Zoo.

The research is said to provide the first evidence that consolation in primates, such as hugging and stroking, can reduce stress levels after a fight.

The behavior could indicate some level of empathy, Dr Orlaith Fraser told the British Association Science Festival.

“We can’t actually say what’s going on in a chimpanzee’s mind; we can only deduce from their behavior what’s going on,” the Liverpool John Moores University researcher said.

“Because this behavior is actually reducing stress levels and it’s being offered by a valuable partner, it seems likely that this is an expression of empathy.”

A bit of sympathy

Dr Fraser and colleagues spent 18 months observing 22 adult chimps at Chester Zoo.

They watched closely what happened immediately after the animals had a scrap – perhaps a fight over food, a mate or simply where to sit.

In about 50% of cases, the victim in the fight would be consoled by another member of the group. The soothing was always done by a valuable – or best – friend, a chimp with whom the victim would routinely play or share food.

Chimps at Chester Zoo (S.P.Hill)

Feeling better after a kiss

The consolation usually took the form of a kiss or embrace, a grooming session or even play.

The scientists could see that this activity had the effect of reducing stress levels, indicated by the return to the animals’ normal activities of self-scratching and self-grooming.

“Sympathetic concern” has also been observed in gorillas, bonobos, dogs and even rooks – but it is the calming effect that it had on the Chester Zoo chimps which is said to be a new observation.

“If these chimpanzees are actually motivated by empathy to console victims of aggression, they must first of all be able to recognize that the victim is distressed and then they must know what to do in order to act appropriately to respond to this distress,” said Dr Fraser.

“This is something often thought to be a unique trait to humans, so understanding the link between consolation and stress reduction in chimpanzees is an important step towards understanding whether or not chimpanzees are capable of this level of empathy.”

The results of the Chester Zoo study were recently published in the journal Proceedings of the National Academy of Sciences.

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