Could a neutron beam help stop train derailments?

Scientists are using neutron radiation to look inside solid steel and analyse the stresses within rail tracks. This research will ultimately improve the safety and operational and repair efficiency of heavy-haul railways.

The wheels of heavily laden trains place considerable rolling-contact loading on rail tracks. The heavy loads can change the material properties near the running surface and within the railhead—causing “fatigue”. A number of serious incidents, including derailments, have been attributed to rail failures resulting from rolling-contact fatigue and accumulated residual stress.

Bragg Institute instrument scientist Dr Vladimir Luzin is looking at fatigue in insulated rail joints (IRJs) within a research project initiated by the Cooperative Research Centre for Rail Innovation. IRJs are an integral part of rail track systems, but they are also weak points, and their replacement is the single largest track maintenance cost in New South Wales, apart from ballast work.

“When a rail comes out of a factory it has already some residual stress,” explains Vladimir. “Now we are looking at the atomic level to see how these stresses develop through the life of the rail joints.”

Vladimir uses neutron diffraction to see how residual stresses evolve through different production steps and during service. The beauty of neutrons is that they can penetrate steel—unlike X-rays—and they can be used to map the stresses inside the rail components non-destructively.

Manufacturers and operators want to control and minimise these stresses. This research, backed by modellers and metallurgists, will help industry partners cut costs, modify production methods and develop rails of a quality and strength that can handle increasing loads.

Bragg Institute, Australian Nuclear Science and Technology Organisation, Vladimir Luzin, Tel: +61 2 9717 7262, vladimir.luzin@ansto.gov.au,  www.ansto.gov.au

Animals contribute to greenhouse gases

Smoke-belching coal-fired power stations and factories and fossil fuel-guzzling motor vehicles may be seen as the big villains of the global climate change debate, but they aren’t the only ones contributing to the greenhouse effect.

Australia’s hundreds of millions of cattle, sheep, pigs and other agricultural animals – not to mention our native fauna – also release significant amounts of methane and other gases into the atmosphere.

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Dating the hobbit

When Australian and Indonesian scientists revealed their “Hobbit” discovery in 2004, it created a sensation. Homo floresiensis was a previously undiscovered branch of the human family tree, raising images of a lost world of “little people” living on a remote island in eastern Indonesia.

What really excited scientists about the discovery of the one-metre tall adult skeleton in a cave on Flores was the realisation this species had co-existed with Homo sapiens until just 12,000 years ago.

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Reading the hidden clock in a grain of sand

Zenobia Jacobs, University of Wollongong. Credit: timothyburgess.net
Zenobia Jacobs, University of Wollongong. Credit: timothyburgess.net

Dr Zenobia Jacobs wants to know where we came from, and how we got here. When did our distant ancestors leave Africa and spread across the world? Why? And when was Australia first settled?

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How did we get here?

Zenobia Jacobs

University of Wollongong

Zenobia Jacobs wants to know where we came from, and how we got here. When did our distant ancestors leave Africa and spread across the world? Why? And when was Australia first settled?

Zenobia Jacobs, University of Wollongong (photo credit: timothyburgess.net)

These are difficult and controversial questions. But Zenobia has a deep understanding of time and how to measure it. She has developed a way of accurately dating when individual grains of sand were buried with human artefacts. And that technique is transforming our understanding of human evolution.

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