Recent News and Breakthrough


Desktop fabricator may kick-start home revolution A cheap self-assembly device capable of fabricating 3D objects has been developed by US researchers. They hope the machine could kick start a revolution in home fabrication – or "rapid prototyping" – just as early computer kits sparked an explosion in home computing.

Rapid prototyping machines are already used by designers, engineers and scientists to create one-off mechanical parts and models. These create objects by depositing layer upon layer of liquid or powdered material. These machines typically cost from $20,000 to $1.5 million, says Hod Lipson from Cornell University, US, who launched the Fab@Home project with PhD student Evan Malone in October 2006.

The standard version of their Freeform fabricator – or "fabber" – is about the size of a microwave oven and can be assembled for around $2400 (£1200). It can generate 3D objects from plastic and various other materials. Full documentation on how to build and operate the machine, along with all the software required, are available on the Fab@Home website, and all designs, documents and software have been released for free.

Many hands

"We are trying to get this technology into as many hands as possible," Malone told New Scientist. "The kit is designed to be as simple as possible." Once the parts have been bought, a normal soldering iron and a few screwdrivers are enough to put it together. "It's probably the cheapest machine of this kind out there," he adds.

The machine connects to a desktop computer running software that controls its operation. It then creates objects layer-by-layer by squeezing material from a mechanically-controlled syringe. A video shows a completed machine constructing a silicone bulb (16MB, wmv format).

Blame for global warming placed firmly on humankind

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Figure 1. The predicted temperature rise by 2100 is between 1.8 and 4.0°C. This is based on models representing a variety of emissions scenarios and an uncertainty of one standard deviation (grey shading). The orange line is a model where greenhouse gas concentrations were held constant at year 2000 values (Graphic: IPCC)Enlarge

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Figure 2. Precipitation is predicted to rise markedly at high latitudes and drop significantly in the tropics. The figure shows the predicted change in precipitation (in percent) in the decade 2090 to 2099, compared to the period 1980 to1999. Precipitation for December to February is on the left and for June to August on the right. In the coloured areas more than 90% of the models agree precipitation will increase or decrease. In the white areas, less than 66% of the models agreed.Enlarge

The 2nd of February 2007 will one day hopefully be remembered as the day the question mark was removed from the debate on whether human activities are driving climate change, said the head of the UN Environment Programme at the launch of the most authoritative scientific report on climate change to date But predictions of sea level rise are one of the most contentious areas of the report - very recent research has suggested that rises of up to 140 cm are possible (see Shorelines may be in greater peril than thought

). The problem is that the understanding of how warming affects Greenland and Antarctic ice sheets remains limited, and they are predicted to be the most important contributors to change. Estimates of the straightforward melting of ice are incorporated in the IPCC report. But warming may also accelerate the movement of ice in glaciers into the ocean, perhaps by meltwater lubricating the undersides of ice streams.

Susan Solomon, one of the report's lead authors, said there was no published research that quantified this effect, and so it was not included. But she added: “If temperatures exceed 1.9°C to 4.6°C above pre-industrial temperatures, and were to be sustained for thousands of years, eventually we would expect the Greenland ice sheet to melt. That would raise sea level by 7 metres.”

Climate change is also expected to affect the frequency and strength of tropical storms and hurricanes. The latest IPCC report says the activity of tropical cyclones is “likely” to increase over the 21st century. It says “likely” indicates a probability of more than 66%. This is a bolder statement than the World Meteorology Organisation issued in January.

Precipitation patterns will change too by 2100, according to IPCC predictions (see figure 2, right). Mid- to high-latitude regions will see up to 20% more rain and snow, while the tropical regions will see less.

Humans to blame

Considering the human role in causing climate change, the IPCC report is damning: "The understanding of [human] influences on climate has improved since the [2001] report, leading to a very high confidence that human activities" are responsible for most of the warming seen since 1950, says the report’s summary for policymakers. “Very high confidence” is described as “at least a 9 out of 10 chance of being correct”.

Before the industrial revolution, human greenhouse gas emissions were small, and the Our galaxy harbours a black hole called SgrA* that weighs nearly 4 million Suns, based on studies of the motion of stars and gas around it. But it does not appear to be gaining any weight at the moment, since it is not flaring up in X-rays, as happens when it sucks matter towards it.

There are signs that it has had larger meals in the past, however. Astronomers can infer the black hole's dietary history by looking for signs of its X-ray flares reaching and heating up gas clouds nearby. By measuring their distances from the black hole, they can tell how long it took for the X-rays to get there and thus when the flares occurred.

Several studies have shown evidence of past outbursts, including one in 2005 suggesting that SgrA* ate a large meal 350 yeas ago that made it a million times brighter than it is now (see Violent past of Milky Way's black hole revealed).

Now, a study employing the same technique suggests the black hole had another outburst that would have been visible just 60 years ago, had there been any X-ray observatories around to watch it.

Steady rain

Michael Muno of Caltech in Pasadena, US, and colleagues made the discovery, using Chandra to monitor gas clouds near the black hole that glow in X-rays. Until now, no one was sure whether the glow was due to a previous SgrA* outburst or simply a steady rain of charged particles called cosmic rays hitting the clouds.

Muno's team found that the brightness and shape of the glow associated with the clouds changed between 2003 and 2005. Such rapid changes are not consistent with a steady rain of cosmic rays, the researchers say.

Instead, they argue that 60 years ago, SgrA* brightened by a factor of 100,000 when it swallowed something - probably a cloud of gas and dust - of about Mercury's mass. (Because of the time it takes light to travel to Earth from the galactic centre, the event actually occurred about 26,000 years ago, but it would not have been visible from Earth until 60 years ago.)

Wolf down

Inventor Matthew Jarman gives some examples. If the programme uses the words "serial killer", the system could block a programme altogether. The same could go for anything that promises an appearance by Pamela Anderson.
The word "damn" could be acceptable on the Discovery Channel, but muted on all movie channels. And the word "bitch" might only be permitted during a programme about pets, and never if preceded by "you". Of course, parents could override everything with a password.

Radio tyre warnings

Checking tires for tread wear is a dirty job, and not easy to do accurately. But drivers need to know when a tyre tread has worn down to 3 millimetres or less, at which point road holding starts to suffer. IBM has a neat way for a car to monitor itself and display a warning on the dashboard when its tyres need changing.
Passive RFID tags are moulded into the tire tread, or stuck into the grooves. While the tags are still in place they reply to a trigger signal continually beamed from an antenna mounted beneath the car. But, as the tread wears out some of the tags are shed and stop responding. So the car automatically "knows" when its tires are getting dangerously thin.
A vehicle could also tell which tire is needs changing because the radio antenna is mounted off centre and thus at unequal distances from all four wheels. So the reply signals received from each tyre has a slightly different delay. The same system could work with trucks and aircraft tires too, IBM says.
Deep fried detector

Here’s an idea for anyone who's felt sick after eating greasy fried food. Honeywell, based in New Jersey, US, has come up with an acoustic wave sensor that fits inside a deep fryer and constantly monitors the quality of cooking oil.

Fatty acids build up as oil is used in a fryer and eventually becomes deposited on food cooked in this way. Ultimately, this can cause indigestion for those who eat deep fried foods, Honeywell warns. Its acoustic sensor could detect this build up and warn a chef that the oil needs changing

While bringing new results to topology, Perelman’s work brought new techniques to geometry. It cemented the central role of geometric evolution equations, powerful machinery for transforming hard-to-work-with spaces into more-manageable ones. Earlier studies of such equations always ran into “singularities” at which the equations break down. Perelman dynamited that roadblock.
In fact, Perelman was already well on his way to a solution. In 1995, the 29-year-old St. Petersburg native had returned to Russia after a 3-year sojourn in the United States, where he had met Hamilton and learned about Ricci flow. For the next 7 years, he remained mostly incommunicado. Then, in November 2002, Perelman posted on the Internet the first of three preprints outlining a proposed proof of the geometrization conjecture. To experts, it was immediately clear that Perelman had made a major breakthrough.

Source: Science, 22 December, 2006



 

Unlike commercial equipment, the Fab@Home machine is also designed to be used with more than one material. So far it has been tested with silicone, plaster, play-doh and even chocolate and icing. Different materials can also be used to make a single object – the control software prompts the user when to load new material into the machine. Malone and Lipson hope Fab@Home will grow into a community of enthusiasts who share designs for 3D objects and even modify the machines for themselves. This will prompt the emergence of widespread personal fabrication, Lipson hopes. "We think it's a similar story to computers," he explains. "Mainframes had existed for years, but personal computing only took off in the late seventies." A cheap self-assembly computer called the Altair 8800, launched in 1975, sparked the rapid development of personal computing, he notes: "We hope Fab@Home can do the same for rapid prototyping."

Copy cat

Adrian Bowyer, who is also working on rapid prototyping machines at Bath University, in the UK, agrees that the technology could have mass appeal once the equipment is cheap enough. One of his own machines can even make some of its own parts (see

3D printer to churn out copies of itself
).

"Fab@Home is an interesting idea; it should be easy for anyone in the world to build," Bowyer says. "Once you've used one you never want to go back, it's liberating and enormously fun." Bowyer believes the technology could one day even replace traditional models of manufacturing.Bowyer adds that the Fab@Home machine could probably already be used to make many cheap injection-moulded products already on the market: "I can imagine people swapping plans of things to make online, or paying to download them instead of going to the shop. Source:http://www.newscientisttech.com/article/dn10922?DCMP=NLC-nletter&nsref = The new Intergovernmental Panel on Climate Change report says there is 90% certainty that the burning of fossil fuels and other human activities are driving climate change. Read the global reaction to the report here.

“The word unequivocal is the key message of this report,” said Achim Steiner, executive director of UNEP, adding that those who have doubts about the role of humans in driving the climate “can no longer ignore the evidence”.

The IPCC report says the rise in global temperatures could be as high as 6.4°C by 2100. The report also predicts sea level rises and increases in the intensity of hurricanes. It is the work of 1200 climate experts from 40 countries, who have spent six years reviewing all the available climate research. It was released in Paris, France, on Friday (read the 21-page summary here, pdf format). Listen to audio from today's press conference.

The last IPCC report, issued in 2001, predicted that temperatures would rise by 1.4°C to 5.8°C by 2100, relative to 1990 temperatures.

But the new report says temperature rises by 2100 could, in the most extreme scenarios, range from 1.1°C and 6.4°C. The most likely range is 1.8°C to 4.0°C (see figure 1, right), with the report predicting that 4°C is most likely if the world continues to burn fossil-fuels at the same rate (read the The impacts of rising global temperatures).

Melting, moving ice

Rises in sea levels are predicted by the new report, threatening low-lying areas of land around the world. As the oceans warm, their waters expand, while rising temperatures also increase the melting of the ice sheets that cover Greenland and Antarctica. In 2001, the IPCC predicted that sea levels would rise by between 9 and 88 centimetres by 2100, relative to 1990 levels. The new report says rises could range from 18 cm to 59 cm. The top end of the range corresponds to a fossil-fuel intensive future (see A1F1 scenario in Modelling the future climate: the baseline scenarios

. Rises in sea levels are predicted by the new report, threatening low-lying areas of land around the world. As the oceans warm, their waters expand, while rising temperatures also increase the melting of the ice sheets that cover Greenland and Antarctica.

In 2001, the IPCC predicted that sea levels would rise by between 9 and 88 centimetres by 2100, relative to 1990 levels. The new report says rises could range from 18 cm to 59 cm. The top end of the range corresponds to a fossil-fuel intensive future (see A1F1 scenario in Modelling the future climate: the baseline scenarios). atmospheric concentration of carbon dioxide – the main greenhouse gas – was about 280 parts per million (ppm).
Thanks largely to the burning of fossil fuels and changes in land use, such as agricultural exploitation and deforestation, the atmospheric concentration of carbon dioxide reached 379 ppm in 2005, says the IPCC.
Gold standard

The IPCC draws together the world's leading climate experts to review and assess all available research, under the auspices of UN Environment Programme and the World Meteorology Organization.

The result of their assessment, which is done every five to six years, establishes what is considered the gold standard of consensus on climate change science.

The latest IPCC report was written by hundreds of experts and reviewed by hundreds more, from 113 countries. It is being released in stages during 2007. The first chapter, released on Friday, deals with the scientific basis for climate change.

The next two parts of the IPCC's 2007 assessment, plus a synthesis, will be released throughout the year. Part 2, dealing with the impacts of climate change and our vulnerability to those impacts, will be released in April. Part 3, to be released in May, deals with how we might mitigate these impacts.

Source:http://environment.newscientist.com/article/dn11088-blame-for-global-warming-placed-firmly-on-humankind.html

For Milky Way's black hole, it's feast or famine

The giant black hole at our galaxy's centre ate something about as massive as Mercury 60 years ago, new results from the Chandra X-ray Observatory suggest. The finding adds to previous evidence that the black hole, which is currently starved, does in fact devour things from time to time.

As this short blast of X-rays expands from the vicinity of the black hole, it hits different parts of the surrounding gas clouds. This causes the changes in the shape and brightness of the X-ray glow seen by Chandra, they say.

Combined with earlier results, the new findings are helping to piece together a picture of SgrA*'s feeding habits. "We have evidence that maybe every 100 years, the black hole gets bright," Muno says.

This suggests it wolfs down clumps of matter from time to time, rather than just steadily feeding on the wind from nearby stars, as was once believed, he says. Watch an animation of a black hole feeding frenzy.

Although scientists would be excited to see a new outburst of this size from SgrA*, it is safer to observe the echoes from past ones. A directly observed outburst would be very bright. "We wouldn't really want to look at it with Chandra because it might damage the detector unless we took some special precautions," Muno says.

The results were presented on Wednesday at a meeting of the American Astronomical Society in Seattle, Washington, US.

Source:http://space.newscientist.com/article/dn10935?DCMP=NLC-nletter&nsref=dn10935 Invention: Personal TV censor

Personal TV censor

Worried about your kids watching the wrong stuff on TV? Don't trust the off icial suitability ratings either? An inventor in Salt Lake City, Utah, thinks he has the answer.

A computer connected to a TV set or Personal Video Recorder (PVR) simply monitors electronic programme guides along with the closed captioning text that accompanies programmes for hard of hearing viewers. Software then searches for dubious key words and the computer decides – based on the user's preferences – whether to block the entire programme or simply mute the sound for a short while.
The system consists of an antenna that generates acoustic waves and a transducer made from a piezoelectric component, which picks up the acoustic wave and converts it into an electrical signal. The sensor is coated with material that reacts with fatty acids.
The acoustic waveform is damped and modified as fatty acids attach. A connected computer analyses this waveform signal and issues a warning to change the oil when it builds up too much.
Source:http://www.newscientisttech.com/article/dn11054?DCMP=NLC-nletter&nsref=dn11054 Breakthrough of the Year: The Poincare Conjecture Proved

Previous year’s Breakthrough salutes the work of a lone, publicity-shy Russian mathxxxxxxiiiiiiitytyematician named Grigori Perelman, who was at the Steklov Institute of Mathematics of the Russian Academy of Sciences until 2005. The work is very technical but has received unusual public attention because Perelman appears to have proven the Poincaré Conjecture, a problem in topology whose solution will earn a $1 million prize from the Clay Mathematics Institute.

Grigori Perelman’s proof of the Poincaré conjecture qualifies at least as the Breakthrough of the Decade. But it has taken them a good part of that decade to convince themselves that it was for real. In 2006, nearly 4 years after the Russian mathematician released the first of three papers outlining the proof, researchers finally reached a consensus that Perelman had solved one of the subject’s most venerable problems. But the solution touched off a storm of controversy and drama that threatened to overshadow the brilliant work.

Perelman’s proof has fundamentally altered two distinct branches of mathematics. First, it solved a problem that for more than a century was the indigestible seed at the core of topology, the mathematical study of abstract shape. Most mathematicians expect that the work will lead to a much broader result, a proof of the geometrization conjecture: essentially, a “periodic table” that brings clarity to the study of three-dimensional spaces, much as Mendeleev’s table did for chemistry.



 

 

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