How a 3D printer could build your next house in 24 hours

WAITING six months for your house to be built? Soon, you will "print" a home in less than a day.
Once the domain of tech geeks, 3D printing is now having a serious impact on the wider world.
First it was prototype shapes for designers.
Then it was models and some moulded medical components.
Now, its lego pieces, guns, games and replaceable mechanical parts.
Next, it's your home.
Professor Behrokh Khoshnevis, from the University of Southern California, has explained how a concrete-style material could be used to "print" structures and walls three times stronger than standard concrete in a process he calls Contour Crafting.

Square walls and windows could quickly become a thing of the past: there is no need for convenient mass-produced flat-pack materials here.
Exotic housing designs will be limited only by the imagination - and gravity, Professor Khoshnevis said.
And he says costly, slow and labour intensive construction processes will become a thing of the past.
"Printing" concrete works in much the same way as household 3D printers print shapes out of plastic: a pool of raw material is layered into shapes by a "print head", allowed to set quickly, then another layer applied.
When building a house, the scale is much larger but the concept much the same.
A huge gantry would be positioned on rails on the construction site, and multiple large "print heads" would build the house from the ground up - one layer at a time.
Even plumbing and electrics can be inserted by the system.
Where to next?
Professor Khoshnevis believes this construction technique can be applied in space - building bases on the moon, Mars and beyond.

Climate sceptic reborn a believer

On ABC Environment last week, we ran an opinion piece by Michael Mann - the guy who compiled the famous 'hockey stick' graph showing global temperatures leaping up in recent years.

Our op-ed provoked a large number of comments doubting the evidence for climate change.
Yet among those who deny that climate change is real, there appears to have been a palpable shift away from a refusal to accept the climate is warming and towards those who doubt the severity of the damage.
It's a subtle but important shift, and suggests that holding the view that climate change is not occurring is intellectually untenable in the long-term.
American physicist Richard Muller is one climate sceptic who has recently changed his mind after reviewing the evidence.
Muller crunched a bunch of numbers to do with global temperatures and announced in the New York Times that he is a "converted sceptic". It was this opinion piece in arguably the world's most influential paper that set tongues wagging about climate change all over again.
Muller had previously been claimed by those unconvinced by the science as one of their own, because he questioned the validity of Mann's 'hockey stick' graph, used by Al Gore in his film An Inconvenient Truth.
The disagreement between Mann and Muller, a rather arcane arm wrestle over data methodology, was used as evidence that the science was not, in fact, settled. It was fuel for thousands of climate sceptic blogs the world over.
Muller had so many concerns over the raw data and the tidied-up data that he just wasn't convinced the world was experiencing unprecedented warming. However, in October last year, Muller announced the findings of his own research in the Wall Street Journal. "Global warming is real," he wrote.
At the time, climate science circles welcomed another scientist into the ranks of those convinced by the evidence. But Muller was still not entirely sure what had caused this warming. "How much of the warming is due to humans and what will be the likely effects? We made no independent assessment of that," he said.
Nearly a year later, he is convinced: "I'm now going a step further: Humans are almost entirely the cause," he wrote in the NYT.
He has now written up his findings and submitted them to the academic Journal of Geophysical Research - Atmospheres.
Bjorn Lomborg is another high-profile climate sceptic who changed his mind after reviewing the evidence. He now believes climate change is real, but that it won't be the calamity predicted by some. Other converts include conservative radio hosts, ex-politicians, current politicians (Tony "absolute crap" Abbott), journalists and publishers. See here and here.
The persuasion of a scientist by evidence that the globe is warming and humans are to blame is not, in itself, particularly remarkable. It is, after all, what scientists do best: look at evidence gathered for a particular hypothesis and try to pick holes in it. Muller, in this case, found that he could not find holes big enough to sink the hypothesis.
The fact that Muller's confession reinvigorated the climate conversation is not remarkable either: those who are convinced by the evidence are frustrated by the sluggish pace of action to combat climate change and therefore keen to re-emphasise the urgency; and those who are unconvinced by the evidence are always keen to hold up action because they view it as unnecessary and potentially damaging to our way of life.
What is interesting is the subtle shift in attitudes to Muller's pronouncement.
There are varied views in relation to climate science. There are those who unquestioningly accept what scientists from reputable organisations say, without looking into the evidence themselves. Most Australians would fall into that category.
Then there are the folks who do a bit of digging and come to the conclusion that the scientists are right.
Then there are the diggers who come to a separate conclusion.
Some of them refuse to believe temperatures are showing increases: the Galileo Movement states this on its website.
Some acknowledge the increase but doubt the role of carbon dioxide: Australian blogger Jo Nova is on the record as doubting the role of CO2.
Some accept the role of CO2 but doubt humans' contribution - Alan Jones is a notable example, frothing to Professor David Karoly that the human contribution of an additional 3 per cent of carbon dioxide can't possibly have an effect.
Some say it's getting warmer, and that CO2 is the cause, and that humans add to the CO2, but they think the predictions of global ecosystem collapse are a bit overblown.
Over time, it seems that the weight of evidence is pushing those who disbelieve climate science further and further towards the view of the majority of researchers working in the area. Few so-called climate sceptics now doubt that humans play a role; fewer still doubt that temperatures are rising.
The roadblocks that have slowed or prevented action to reduce the effects of climate change are being smoothed.
While there will always be hold-outs who cling to their own beliefs despite the evidence, the trend away from complete denial can only be positive news for those on the road to addressing climate change.

http://www.abc.net.au/news/2012-08-15/phillips-climate-sceptic-reborn-a-believer/4199130