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Tuesday, September 23, 2008

World's Thinnest Balloon Created: Just One Atom Thick


Graphene membrane one-atom thick can stretch like a balloon. The membrane is ultra-strong, leak-proof and impermeable to even nimble helium atoms. (Credit: MIT, Jonathan Alden, Brian K. Ireley)

Using a lump of graphite, a piece of Scotch tape and a silicon wafer, Cornell researchers have created a balloonlike membrane that is just one atom thick -- but strong enough to contain gases under several atmospheres of pressure without popping.

And unlike your average party balloon -- or even a thick, sturdy glass container -- the membrane is ultra-strong, leak-proof and impermeable to even nimble helium atoms.

The research, by former Cornell graduate student Scott Bunch (now an assistant professor at the University of Colorado), Cornell professor of physics Paul McEuen and Cornell colleagues, could lead to a variety of new technologies -- from novel ways to image biological materials in solution to techniques for studying the movement of atoms or ions through microscopic holes.

The work was conducted at the National Science Foundation-supported Cornell Center for Materials Research.

Graphene, a form of carbon atoms in a plane one atom thick, is the strongest material in the world, with tight covalent bonds in two dimensions that hold it together even as the thinnest possible membrane. It's also a semimetal, meaning it conducts electricity but changes conductivity with changes in its electrostatic environment.

Scientists discovered several years ago that isolating graphene sheets is as simple as sticking Scotch tape to pure graphite, then peeling it back and re-sticking it to a silicone dioxide wafer. Peeled back from the wafer, the tape leaves a residue of graphite anywhere from one to a dozen layers thick -- and from there researchers can easily identify areas of single-layer-thick graphene.

To test the material's elasticity, the Cornell team deposited graphene on a wafer etched with holes, trapping gas inside graphene-sealed microchambers. They then created a pressure differential between the gas inside and outside the microchamber. With a tapping atomic force microscope, which measures the amount of deflecting force a tiny cantilever experiences as it scans nanometers over the membrane's surface, the researchers watched the graphene as it bulged in or out in response to pressure changes up to several atmospheres without breaking.

They also turned the membrane into a tiny drum, measuring its oscillation frequency at different pressures. They found that helium, the second-smallest element (and the smallest testable gas, since hydrogen atoms pair up as a gas), stays trapped behind a wall of graphene -- again, even under several atmospheres of pressure.

"When you work the numbers, you would expect that nothing would go through, so it's not a scientific surprise," said McEuen. "But it does tell you that the membrane is perfect" -- since even an atom-sized hole would allow the helium to escape easily.

Such a membrane could have all kinds of uses, he added. It could form a barrier in an aquarium-like setup, for example, allowing scientists to image biological materials in solution through a nearly invisible wall without subjecting the microscope to the wet environment. Or, researchers could poke atomic-sized holes in the membrane and use the system to study how single atoms or ions pass through the opening.

"This could serve as sort of an artificial analog of an ion channel in biology," McEuen said -- or as a way to measure the properties of an atom by observing its effect on the membrane.

"You're tying a macroscopic system to the properties of a single atom," he said, "and that gives opportunities for all kinds of single atom sensors."

The paper's co-authors are Cornell physics graduate students Arend van der Zande and Jonathan Alden; postdoctoral researcher Scott Verbridge; and professors Jeevak Parpia and Harold Craighead.

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New ocean sparks questions about changing maps, textbooks

By Randi Weiner

Shortly after school started this year, Thiells Elementary School teacher Amy Becker was working with her fourth-grade students on their map skills when one child asked why she wasn't mentioning the fifth ocean.

Fifth ocean? All the maps, the globe and the textbooks mention four oceans: the Atlantic, Pacific, Indian and Arctic.


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"So we researched it," Becker said. "There really is a fifth ocean. They pulled it up on the Internet. We're not actively teaching it in our curriculum, so it was really cool for the children to learn about this."

In the spring of 2000, the International Hydrographic Organization, based in Monaco, designated all the water below 60 degrees south latitude the Southern Ocean. The ocean surrounds Antarctica wholly, and used to be shown as the place where the Pacific, Atlantic and Indian oceans met at the bottom of the world.

Since then, cartographers and others, including the National Geographic Society and the U.S. Geological Survey, have debated whether the Southern Ocean should, in fact, become part of the lexicon.

Some European countries don't recognize it, and the most recent query to the U.S. Board on Geographic Names doesn't specify whether the new ocean has been accepted. The board's approval is necessary before the National Oceanic and Atmospheric Administration places the name on its charts. So far, the name isn't there.

And they're not the only ones unsure.

"We went back and forth on it," said Terry Donovan, a cartographer with Replogle Globes, which about two years ago began adding the Southern Ocean - in parentheses to designate its optional status - to the more detailed globes it manufactures.

"It's gaining more acceptance," he said.

In the classroom, the Southern (sometimes Antarctic) Ocean is a hit-or-miss proposition. Steven Forman, an assistant principal at Ramapo High School and a former social studies teacher, said the textbooks don't mention it but a map he looked at did.

"It's discussed in our environmental science classes, where they talk about the ecosystem that's down there," he said.

Forman said he thought the IHO decided to rename the water around the Antarctic continent as a way to better describe the area when discussing international fishing and hunting treaties. Scientists have been spending more time studying the bottom of the world because of global warming worries, he said. They found the currents, fish and plant life there seem to be part of a separate ecosystem from that of the Pacific, Atlantic and Indian oceans, which would argue for a separate ocean designation.

Ed Martin, chief of the customer affairs branch of the National Services Division of the Office of Coast Survey, a division of the NOAA, said information about the Southern Ocean appears to be available online for those who know to look for it, but it's been slow to trickle onto the printed page.

"People think nowadays that putting something up on the Internet means it gets to everybody, but that's not true," he said. "How do you get it to the books and students? That's a good question."

Becker said her class researched everything they could find on the Southern Ocean and ended up linking map reading, Internet research, discussion and writing to explain what it was.

"When I go to my social studies curriculum meeting, I'll bring all my research with me and we can start including it in our curriculum," she said. "Everything has to be updated."

Reach Randi Weiner at rcweiner@lohud.com or 845-578-2468.

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End of the world postponed as broken Hadron Collider out of commission for two months

The £3.6bn Large Hadron Collider will be out of action for around two months after magnets over-heated, a spokesman for the project said today.

The European Organisation for Nuclear Research (Cern) said damage to the huge project below Switzerland, discovered yesterday, was worse than it first thought.

The collider, which was designed to send particles around a 16 mile circuit in a bid to unravel some of the secrets of the universe, was shut down to allow an investigation to take place.

Spokesman James Gillies said early indications were that there was a fault in an 'electrical inter-connection' between two magnets.

Big Bang machine

Scientists work on part of the Large Hadron Collider which some feared would threaten the end of the world. The machine is now out of order for two months

The fault led to a leak of helium into the tunnel and the team's in-house fire brigade turned out.

'That was standard procedure,' Mr Gillies said.

He played down the fault, which happened nine days after the machine was started.

'These kind of teething problems happen with particle colliders,' he said.

'It will take a couple of months to fix it because we operate at a very low temperature and we will have to warm the magnets up to room temperature, fix the fault, then cool them back down again.

Big Bang machine

The huge magnets of the world's most powerful particle accelerator over heated to put it out of action for two months

'The warm-up and cool-down will each take a couple of weeks.'

The cost of the damage caused was not yet known.

'An investigation is underway and as soon as we have the full details, we will release them," added Mr Gillies.

The collider requires temperatures just above absolute zero to allow particles to be steered around the circuit.

But as a result of the fault, the temperature of the magnets rose by around 100C.

Before it was started up last week, some scientists expressed fears that colliding particles could cause black holes to appear, though those concerns were strongly refuted.

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650 Million Year-Old Reef Discovered in Australia’s Outback

Trouble in the LHC: fried wiring and leaking helium to blame

By Tim De Chant

The Large Hadron Collider (LHC) that straddles the Switzerland-France border was beset by an unfortunate equipment failure Friday, September 19—just nine short days after it first hurled particles around its 16.6 mile (27km) track. Scientists with the European Center for Nuclear Research, popularly known as CERN, acknowledged the severity of the damage will delay research at the particle accelerator for a minimum of two months.

LHC operators were putting the most recently installed electrical circuits through their final paces late Friday morning when they noticed a helium leak between the Alice and CMS detectors. Liquid helium supercools the accelerator's magnets to 1.9 degrees Kelvin, a temperature just above absolute zero. Lacking coolant, about 100 magnets warmed by 100 K, prompting scientists to shut down the LHC. The leak also compromised the vacuum within the collider's tubes. The costly damage may also prevent scientists from completing any high-energy collisions this year as the facility shuts down for the winter to save power.

Physicists hope the LHC will help them find the Higgs boson, a particle thought to give mass to matter. They see the Higgs as a missing link, the only particle predicted by the Standard Model that has not been discovered.

Repairs to the damaged sector are still a ways off, as scientists will have to warm the equipment well above operating temperatures—a controlled process that will take weeks. Likewise, after the damage is mended, the affected sector has to be cooled over many weeks.

CERN says faulty wiring is likely the cause of the damage. The tremendous current normally used by the accelerator likely melted a bad connection between two magnets, sparking subsequent failures.

This isn’t the LHC's first setback. Over the weekend of September 13 and 14, workers replaced a malfunctioning 30-ton electrical transformer. To perform the transplant, scientists warmed the tunnel, and then spent most of the following week cooling it down again.

Such mishaps, CERN says, are part-and-parcel of firing up the largest particle accelerator in the world. The LHC is seven times more powerful than the reigning champion, Fermilab's Tevatron outside Chicago. While the first tests at the LHC were low power loops, scientists had planned on completing high-energy collisions as early as October of this year. This most recent incident may push the first exciting experiments into next year.

Yet while the LHC is down, physicists at Fermilab will have more time to continue their quest for information about the Higgs boson particle. Even though the Tevatron is likely not powerful enough to find the Higgs, the Fermilab accelerator is still in the race, with physicists looking to end its storied career with a bang before its 2010 decommissioning.

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It’s Twins!: Evolution and Climate Change Deniers


Photo by Mike Baird bairdphotos.com

Photo by Mike Baird bairdphotos.com

This past summer we saw yet another hot story reverberate around the Denialosphere. Supposedly the ships logs of Lord Nelson and Captain Cook cast doubt upon the truth of anthropogenic climate change (eg “Captain Cook and Lord Nelson’s logs indicate 1730’s global warming wasn’t man made“, “Lord Nelson and Captain Cook’s shiplogs question climate change theories“).

Total nonsense of course, as has been explained at DeSmogBlog “UK Scientist Dismayed by Media Misrepresentation” and Bad Science “Don’t let the facts spoil a good story“. Just another example how the Deniers lie and distort to further their agenda. But there are two interesting things about this and earlier examples of Denier spin.

In the first place, it is spin. Some small kernal of fact is distorted and mutated until it emerges appearing to say the opposite of what it originally said. Rarely do the Deniers seem to make things up out of thin air. Whether this is so that they can argue that their’s is a plausible interpretation of the facts or a subconscious attempt to retain some small shred of integrity by pretending that what they do is not lying cannot be known.

The second interesting thing is how the strategy and tactics of the Climate Change Deniers is identical to those of the Evolution Deniers. This excellent little video by potholer54Creationist Junk Debunked #1 - Introduction

could just as easily be talking about Climate Deniers. It is well worth watching for understanding both Evolution and Climate Change Denier methods, and because it is fun.

One reason for the similar approach is that in at least some cases it is the same people (eg Roy Spencer). Of far greater concern is that this approach actually works, and you need something when you have no facts or evidence.

Advocates of so-called Intelligent Design (Evolution Denial) have been gaining ground pushing their anti-science nonsense into science classrooms. This summer Louisiana passed a law that effectively puts it on the curriculum. Other States are considering doing so as well.

So while some may laugh when they see the Denier nonsense being posted around the internet, the fact is that it must be taken seriously because it is dangerous. The Deniers continue to enjoy too much success in confusing the public about climate science and that is a threat to every living thing on the planet.

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A New Kind of Ocean Pollutant: Noise

Ransom Riggs
by Ransom Riggs

destroyer_2.jpgSleeping with the fishes is getting a lot harder these days. And not because the FBI finally has the mob on the run, either — rather, because noise levels in the world’s oceans are lately reaching staggering levels, in some areas doubling each decade. Whales, dolphins and other marine mammals are finding their feeding and mating patterns disrupted, and some of the noise — like that produced by high-energy military sonar systems — have been linked to outright death in some species of whales.

It’s not so much that the noise we humans produce underwater is greater than what we produce on land, but that creatures of the sea are so much more sensitive to it. Baleen whales emit low-frequency calls that can travel a thousand miles in water — an essential kind of long-distance calling plan for an animal whose kind are far more sparsely distributed than before commercial whaling took hold. Other kinds of whales and dolphins use high-frequency clicks to locate prey, and sound is important to all marine mammals “in ways that are clearly important to their survival, though not completely understood,” according to the BBC.

And it’s not just high-energy sonar from naval operations that’s drowning them out — the engines and propellers of large ships, whose movements across the open ocean are mostly unrestricted, can be a major problem, as well as the seismic blasts associated with offshore drilling operations (drill, Willy, drill!).

Some companies and the Navy have voluntarily turned down the noise (after pressure from the International Fund for Animal Welfare), but the IFAW says it’s not enough: “Humanity is literally drowning out marine mammals,” says its director, Robbie Marsland. “While nobody knows the precise consequences for specific animals, unless the international community takes preventive measures we are likely to discover only too late the terrible damage we’re causing.”

Here’s a sad little video about the effect of sonar on whales:

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Meet Dave, the Man Who Never Takes Out the Trash

By Bryan Walsh

Dave Chameides shows some of his collection of six months' worth of trash in the basement of his home in Los Angeles on July 1

David Chameides is not your average American. For one thing, the TV cameraman owns two Emmy awards — how many do you have? But more importantly, while the average American throws out around 1,700 lbs. of trash annually, for the past year Chameides has thrown out absolutely nothing. A deep green by nature — he also runs a website called Sustainable Dave — beginning in December Chameides decides he would keep all the garbage he created, at home and on the road, in his house. "We have the concept of throwing something away, but in reality, we're just tossing it over our shoulder and forgetting about it," says Chameides. "It wouldn't be so funny if it was really just in your backyard." (Hear Chameides talk about his trash habits on this week's Greencast.)

Essentially, that's what Chameides has been doing. All of his non-recyclable trash — including organic waste like food — is stacked neatly in the basement of his Los Angeles house. He uses a tin box to hold bags of waste paper, and cans of garbage to hold the rest. For organic waste, he put in a worm composter that breaks down leftover food. Beyond that, he didn't create a master plan for his year of no trash. "I didn't really think this through — which is probably for the best," says Chameides. His wife and kids are exempted from the challenge, but not from the neighbors' scoffs. "My wife's friends do make fun of me."

Not only does Chameides carefully pack away any waste he creates at home, he also lugs back trash he may have produced outside the home. Sometimes far outside: On a recent vacation to Mexico with his wife, Chameides dutifully tagged and bagged all the things he would have thrown out, and brought them back with him to the U.S. When he encountered security officials at the airport in Mexico, they were understandably confused. "The woman in the security line opened up my bag and saw all the trash," says Chameides. "She said, 'Que esto?' [What is this?] I told her, 'Basura' — garbage. They just laughed and zipped up the bag."

It didn't take long for Chameides to figure out that the best way to reduce the amount of trash he wasn't throwing away was to simply cut back on the amount of stuff he consumed in the first place. Given that his nickname is Sustainable Dave, that wasn't too hard. "I'm a non-consumer to begin with," says Chameides. "After a month or two I became aware of just how little I was consuming." Through about eight months, Chameides reckons he's kept a little more than 30 lbs. of trash — most of which dates back to the first couple months of the year, before he got the hang of not taking out the trash. The average American, by contrast, would have passed 1,000 lbs by now. (You can keep track of the trash that Chameides is not throwing out on his blog.) "It turned out that it's not that hard," he says. "I'm a pretty normal guy — I just keep my garbage in my basement."

It's easy to mock Chameides's earnest habits, but his quest does highlight an environmental threat that rarely gets attention. Most Americans have now come to believe that littering on the street is wrong, but as Chameides says, just because you throw something out in a proper trashcan doesn't mean it simply disappears. Though America's landfills are in no danger of filling up any time soon, taking out the trash is increasingly costly, with major cities like New York now having to truck their garbage hundreds of miles to reach an open dumping space. That means energy and carbon emissions. Chameides decided to begin his year of no trash after he visited his community's landfill. "It's nearly 40 miles away, and they have 13,000 tons of trash coming in every day," he says. "It's going to close in seven years, and then they'll have to ship the trash all the way to Arizona."

Government and industry can play their part in reducing the trash stream by cutting back on unnecessary waste — especially packaging, which makes up a surprising amount of our garbage. That's a symptom of the sort of culture we've become, one that's disposable, that runs on unthinking convenience. Chameides shows that what we really need to do is simply slow down and think about the waste we're creating, and the easy ways to reduce it, before we end up knee deep in our own garbage. "People ask me, 'Why are you doing this?'" he says. "It's because I want to know more about what my waste footprint is. I don't want to be part of the problem, but part of the solution." That's a sentiment that even average Americans should be able to agree with.

Original here


Rubber ducks help scientists understand global warming

By Jessica Salter

There's a reward for the return of the Nasa ducks Photo: Imagesource

Nasa researchers have dropped 90 ducks into holes in Greenland's fastest moving glacier, the Jakobshavn Glacier in Baffin Bay, between Greenland and Canada.

The toys have each been labelled with the words "science experiment" and "reward" in three languages, along with an e-mail address.

If they are found scientists will be able to track how the water moves through the ice and provide information about the movement of glaciers. Scientists are still unsure about why glaciers speed up in summer and head towards the sea.

One theory is that the summer sun melts ice on top of the glacier's surface, creating pools that flow into tubular holes in the glacier called moulins.

These moulins carry some water to the bottom of the glacier, where it acts as a lubricant to speed the movement of ice toward the coast.

The Jakobshavn Glacier is believed to be the source of the iceberg that sank the Titanic in 1912 and is important to researchers because it discharges nearly 7 per cent of all the ice coming off Greenland.

Alberto Behar of Nasa's Jet Propulsion Laboratory in California said none of the ducks had been reported yet.

"We haven't heard back but it may take some time until somebody actually finds it and decides to send us an e-mail that they have found it," he said.

"These are places that are quite remote so there aren't people walking around."

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