News

Shaving nanoseconds from racing processors

NSF Discoveries - 15 min ago

University of Wisconsin researcher finds hidden efficiencies in computer architecture
More at http://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=130950&WT.mc_id=USNSF_1


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Earth-sized exoplanet discovery

NSF Discoveries - 15 min ago

Gemini confirms Earth-sized planet
More at http://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=131149&WT.mc_id=USNSF_1


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Categories: News

Earth Day in the future: What will it be like?

NSF Discoveries - 15 min ago

Scientists peer into the next decades of environmental change on Planet Earth
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Cosmic slurp

NSF Discoveries - 15 min ago

Georgia Tech researchers use supercomputers to understand and predict signs of black holes swallowing stars
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Crib mattress dangers

NSF Discoveries - 15 min ago

NSF-funded researchers discover harmful chemicals in crib mattresses
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First principles approach to creating new materials

NSF Discoveries - 15 min ago

Solid-state chemistry and theoretical physics combined to help discover new materials with useful properties
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Granite bedrock and sequoia forests 'communicate' in the Sierra Nevada

NSF Discoveries - 15 min ago

Research reveals the coevolution of life and landscapes
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NSF-funded researchers use new models to explore Earth's interior

NSF Discoveries - 15 min ago

New findings from Arizona State University can help explain the geochemistry of lava
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Mapping tool used by Census Bureau has roots in NSF-funded project

NSF Discoveries - 15 min ago

Census Explorer, a new online tool that displays demographic information on maps of states, counties, and neighborhoods, is powered by Social Explorer, a data visualization tool developed by NSF-funded sociologist Andrew Beveridge
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Will the Yellowstone supervolcano erupt in our lifetime?

NSF Discoveries - 15 min ago

Researcher studies the past to predict the future
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Belly up to the bamboo buffet: Pandas vs. horses

NSF Discoveries - 15 min ago

Livestock, particularly horses, have been identified as a significant threat to panda survival
More at http://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=130893&WT.mc_id=USNSF_1


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Snakes Alive! NSF-funded researchers find oldest fossil evidence of modern African venomous snakes

NSF Discoveries - 15 min ago

Seasonal habitats may have given rise to active hunters earlier than previously reported
More at http://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=130818&WT.mc_id=USNSF_1


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Hooked on STEMGenetics

NSF Discoveries - 15 min ago

Genetics curriculum blends teacher-led discussion, online learning and hands-on activities
More at http://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=130811&WT.mc_id=USNSF_1


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Tailoring disease screening programs to individuals

NSF Discoveries - 15 min ago

Researcher developed a customized computer algorithm that provides a better decision support tool
More at http://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=130806&WT.mc_id=USNSF_1


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Catching the Fever

NSF Discoveries - 15 min ago

Particle Fever discovers the human element to physics
More at http://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=130785&WT.mc_id=USNSF_1


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How to make graphene in a kitchen blender

Nature Newsblog - 8 hours 59 min ago

Atomic resolution, scanning transmission electron microscope image of part of a nanosheet of shear exfoliated graphene. Credit: CRANN/SuperSTEM

Don’t try this at home. No really, don’t: it almost certainly won’t work and you won’t be able to use your kitchen blender for food afterwards. But buried in the supplementary information of a research paper published today is a domestic recipe for producing large quantities of clean flakes of graphene.

The carbon sheets are the world’s thinnest, strongest material, both electrically conductive and flexible, and tipped to transform everything from touchscreen displays to water treatment. Many researchers – including Jonathan Coleman at Trinity College Dublin – have been chasing ways to make large amounts of good-quality graphene flakes.

In Nature Materials, a team led by Coleman (and funded by the UK-based firm Thomas Swan) describe how they took a high-power (400 watt) kitchen blender and added half a litre of water, 10 to 25 mls of detergent, and 20 to 50 grams of graphite powder (found in pencil leads). They turned the machine on for 10 to 30 minutes. The result, the team reports: a large number of micrometre-sized flakes of graphene, suspended in the water.

Coleman adds, hastily, that the recipe involves a delicate balance of surfactant and graphite, which he has not yet disclosed (a barrier that dissuaded me from trying it out; he is preparing a detailed kitchen recipe for later publication). And in his laboratory, centrifuges, electron microscopes, and spectrometers were also used to separate out the graphene and test the outcome. In fact, the kitchen-blender recipe was added late in the study as a bit of a gimmick – the main work was done first with an industrial blender (pictured).

Five litres of suspended graphene (in an industrial blender). Credit: CRANN.

Still, he says, the example shows just how simple is his new method for making graphene in industrial quantities. Thomas Swan has scaled the (patented) process up into a pilot plant and, says commercial director Andy Goodwin, hopes to be making a kilogram of graphene a day by the end of this year, sold as a dried powder and as a liquid dispersion from which it may be sprayed onto other materials.

“It is a significant step forward towards cheap and scalable mass production,” says Andrea Ferrari, an expert on graphene at the University of Cambridge, UK. “The material is of a quality close to the best in the literature, but with production rates apparently hundreds of times higher.”

The flakes are not as high-quality as those that the winners of the 2010 Nobel Prize in Chemistry, Andre Geim and Kostya Novoselov from Manchester University, famously isolated by using Scotch Tape to peel off single sheets from graphite. Nor are they as large as the metre-scale graphene sheets that firms today grow atom by atom from a vapour.  But outside of high-end electronics applications, smaller flakes suffice: the real question is how to make lots of them.

Though hundreds of tons of graphene are already being produced each year — and you can easily buy some online — their quality is variable. Many of the flakes in store are full of defects or smothered with chemicals, affecting their conductivity and other properties, and are tens or hundreds of layers thick. “Most of the companies are selling stuff that I wouldn’t even call graphene,” says Coleman.

The blender technique produces small flakes some four or five layers thick on average, but apparently without defects – meaning high electrical conductivity. Coleman thinks the blender induces shear forces in the liquid sufficient to prise off sheets of carbon atoms from the graphite chunks (“as if sliding cards from a deck”, he explains).

Kitchen blenders aren’t the only way to produce reasonably high-quality flakes of graphene. Ferrari still thinks that using ultrasound to rip graphite apart could give better materials in some cases. And Xinliang Feng, from the Max Planck Institute for Polymer Research in Mainz, Germany, says that his recent publication, in the Journal of the American Chemical Society, reports a way to produce higher-quality, fewer-layer graphene at higher rates by electrochemical means. (Coleman points out that Thomas Swan have taken the technique far beyond what is reported in the paper).

As for applications: “the graphene market isn’t one size fits all,” says Coleman, but the researchers report testing it as the electrode materials in solar cells and batteries. He suggests that the flakes could also be added as a filler into plastic drinks bottles – where their added strength reduces the amount of plastic needed, and their ability to block the passage of gas molecules such as oxygen and carbon dioxide maintains the drink’s shelf life.

In another application altogether, a small amount added to rubber produces a band whose conductivity changes as it stretches – in other words, a sensitive strain sensor. Thomas Swan’s commercial manager, Andy Goodwin, mentions flexible, low-cost electronic displays; graphene flakes have also been suggested for use in desalination plants, and even condoms.

In each case, it’s yet to be proven that the carbon flakes really outperform other options – but the new discoveries for mass-scale production mean that we should soon find out. At the moment, an array of firms is competing for different market niches, but Coleman predicts a thinning-out as a few production techniques dominate. “There are many companies making and selling graphene now: there will be many fewer in 5 years’ time,” he says.

Categories: General, News

Another way to look at the "EDGE effect": "Evolutionarily Distinct and Globally...

Ernst Mayr Library Facebook - Sat, 2014-04-19 17:48
Another way to look at the "EDGE effect": "Evolutionarily Distinct and Globally Endangered", a new conservation program.
http://news.mongabay.com/2014/0410-hance-edge-birds.html?fbfnpg


Giant ibis, little dodo, and the kakapo: meet the 100 weirdest and most endangered birds
news.mongabay.com
The comic dodo, the stately great auk, the passenger pigeon blotting out the skies: human kind has wiped out nearly 200 species of birds in the last five hundred years. Now, if we don't act soon we'll add many new ones to the list: birds such as the giant ibis, the plains-wanderer, and the crow hone…
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