As we walk along a forest path, the soil beneath our feet seems like a uniform substance. However,
The post A tale of 2 (soil) cities has been published on Technology Org.
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Wednesday, 22 July 2015
Space-eye-view could help stop global wildlife decline
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Conservation scientists need to collaborate with space agencies, such as NASA and the European Space Agency, to identify measures which help track biodiversity declines around the world. Scientists are calling for urgent cooperation.
via Science Daily
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Conservation scientists need to collaborate with space agencies, such as NASA and the European Space Agency, to identify measures which help track biodiversity declines around the world. Scientists are calling for urgent cooperation.
via Science Daily
Zazzle Space Exploration market place
Vintage Astronomy Celestial Copernican Planisphere Poster
Here's a great poster featuring a beautiful image from deep space
tagged with: constellations, retro, vintage, celestial, americana, antique map, nostalgic, atlas, copernicus, star chart, antique celestial
Vintage illustration Renaissance era astronomy and celestial image featuring an antique map with the sun at the center of the universe and planets circling, created in 1660 by Andreas Cellarius. Copernican Planisphere, from The Celestial Atlas, or the Harmony of the Universe. Andreas Cellarius (c.1596-1665) was a Dutch-German cartographer, best known for his Harmonia Macrocosmica of 1660, a major star atlas, published by Johannes Janssonius in Amsterdam.
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Click to customize with size, paper type etc.
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tagged with: constellations, retro, vintage, celestial, americana, antique map, nostalgic, atlas, copernicus, star chart, antique celestial
Vintage illustration Renaissance era astronomy and celestial image featuring an antique map with the sun at the center of the universe and planets circling, created in 1660 by Andreas Cellarius. Copernican Planisphere, from The Celestial Atlas, or the Harmony of the Universe. Andreas Cellarius (c.1596-1665) was a Dutch-German cartographer, best known for his Harmonia Macrocosmica of 1660, a major star atlas, published by Johannes Janssonius in Amsterdam.
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Click to customize with size, paper type etc.
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Researchers make scalable arrays of 'building blocks' for ultrathin electronics
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For the first time, researchers have combined a novel synthesis process with commercial electron-beam lithography techniques to produce arrays of semiconductor junctions in arbitrary patterns within a single, nanometer-thick semiconductor crystal. The process transforms patterned regions of one existing, single-layer crystal into another. The two semiconductor crystals formed sharp junctions, the desired building blocks of electronics.
via Science Daily
For the first time, researchers have combined a novel synthesis process with commercial electron-beam lithography techniques to produce arrays of semiconductor junctions in arbitrary patterns within a single, nanometer-thick semiconductor crystal. The process transforms patterned regions of one existing, single-layer crystal into another. The two semiconductor crystals formed sharp junctions, the desired building blocks of electronics.
via Science Daily
Silicon Valley could save the world from climate change. But we don't want them to.
Science Focus
original post »
Silicon Valley could save the planet. All they need to do is combine their entrepreneurial brilliance with an enormous infusion of cash, and, more importantly, have our society grant them the cultural permission to lead us to a green future.
But we don't want that. And, frankly, that's why we peons annoy the titans of tech so much.
Why won't we hand our environmental challenges to our top technologists to solve? After all, these are among the world's most successful people at identifying unsolved problems and tackling them. And they're loaded with enough money, resources, and cache to get things done.
The reason is simple: We're afraid.
Instead we demand solutions from policymakers — not because we think they're the biggest geniuses, but because we think only the government has the legitimate authority to do big binding things that affect us all, which is what stopping climate change requires.
What's more, many of us think that only government can do the right thing in a divided world. Regardless of our partisanship or our policy preferences, we're increasingly doubtful that big goals can be met except by coercive force. In fact, we suspect that, at bottom, everything is a matter of coercive force.
Consider, for a moment, Jeb Bush. After teasing environmentalists with dreams of a "moderate" Republican — as opposed to yet another "denier" — Bush recently laughed off restrictive policymaking as a solution to our climate challenges, enthusing instead over, well, Silicon Valley.
Innovation and technology, said Bush, are "the source of a lot more solutions than any government-imposed idea and sometimes I sense that we pull back from the embrace of these things." Instead, Americans should "tear down the barriers," allowing new inventions to "accelerate in our lives to find solutions" to our humanity-wide problems.
Speaking for a host of green activists at their wits' end, Salon political writer Simon Maloy called Bush's vision "an impossibly vague nothingburger […] that gives the impression that Jeb cares about climate change as he advocates for the status quo." And indeed, that's one way the story Bush tells could wind up.
Here's another real possibility: Bush's vision could actually make enormous progress toward soliving our environmental struggles.
Why not trust our technologists to actually tackle the difficulties our scientists warn us about? Why do we put our faith in government not even to compel us to do great things, but to stop us from doing little things that add up, such as emit carbon?
We are setting our sights too low, envisioning a government that just skims some value off the top of our emissions in the form of taxes and fees. This is not nearly enough. And our government is incapable of doing the big things that actually need to be done.
At Vox, David Roberts warns that reversing the trend line of net emissions requires us "to imagine all of human society turning on a dime, beginning in 2030, deploying massive amounts of nuclear, bioenergy, wind, and solar, and doing so every year for decades." That public effort "may not violate the laws of physics," says Roberts, "but it is unlikely, given what we know about human beings, path dependence, and political dysfunction."
It's almost as if the best approach is to set aside our lawmakers' climate policy agendas and focus on rendering our old energy technologies ridiculously obsolete. That would take a ton of work, yes. It would probably take government subsides on a massive scale. But if we really wanted to, we could create an energy-industrial complex every bit as powerful, wealthy, and supreme as the military-industrial complex that grew out of World War II. Just look at what one person, Elon Musk, has been able to achieve with even modest government subsidies.
Humanity has a simple problem: We are not good enough at making and using energy. We're slow, inefficient, fearful, and unserious about how plentiful energy can be.
Why don't we turn Washington into the biggest venture capitalist in the world, and hand Silicon Valley a blank check marked "climate"? Because it makes them masters of the universe. Yes, it's all about our fear again. Even worse than lining their pockets with "public money" we envision going to poor people instead, letting our tech titans lead would make them a civilization apart: plainly higher and better than us, in a way that cuts to the heart of our egalitarian envy and pride.
Unless we get over that resentful queasiness about the new ruling techno-class we're winding up with anyway, we'll just keep choking on climate.
#science
» see original post http://theweek.com/articles/556627/silicon-valley-could-save-world-from-climate-change-but-dont-want
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Can these glasses read your mind? A look at the Wild West of brain gadgets.
Science Focus
original post »
The headset I was wearing was supposed to be reading my brain.
Seated across from its inventor, I slid on the sleek wireless device, called Narbis Neurofeedback Glasses. A five-pronged sensor sat on my head, dark lenses shaded my eyes, and two arms hooked behind my ears. As I read a book, the lenses darkened and cleared, allegedly in sync with the drift of my attention.
Devon Greco, the 29-year-old founder of Narbis, wanted to make a brain-training device to help users focus. And unlike most biofeedback tools, his wireless glasses can be used far from a computer screen. Narbis recently raised \$42,997 for its Neurofeedback Glasses in a Kickstarter campaign, and plans to sell the devices at \$295 apiece. The glasses are being targeted at athletes and clinicians who treat ADHD, among others.
But do they really work?
Brain gadgets are becoming ever more popular, as techniques for stimulating or recording from the brain migrate from labs to the garages of do-it-yourself inventors like Greco. Neurofeedback tools like Narbis are one popular trend; "brain zappers" that use transcranial direct cortical stimulation, or tDCS, are another.
The much-hyped tDCS is a cautionary tale. The technique is supposed to ease everything from depression to hyperactivi ty to back pain by electrically stimulating the brain. But amidst hope and enthusiasm, many scientists and entrepreneurs have confused "claims with reality," as Dr. Vincent Walsh cautioned his colleagues in the journal Brain Stimulation. "We constantly sex up our findings for the press, and the result is an understandably overoptimistic public, because we — no one else — have misled them."
Despite a 2008 Harvard study suggesting that tDCS lessens pain, more recent research paints a different picture. In a recent analysis for Cochrane, a World Health Organization-affiliated NGO, Neil O'Connell and colleagues showed that the evidence that tDCS reduces back pain is overwhelmingly weak.
Jared Horvath, a doctoral candidate at the University of Melbourne, used tDCS to study ADHD at Harvard for two years, without success, before deciding to investigate the tool itself. In a large meta-analysis of the brain zappers, he showed that few of the reported effects survive replication by multiple groups. The few that do are small effects that shrink over time, suggesting that the early positive results were misleading outliers.
As a 2012 paper pointed out, the sensationalization of biomedical devices often starts not with entrepreneurs, but with scientists, who spin reports of new discoveries.
"The scientist and the innovative entrepreneur have similar motivations," says O'Connell, a lecturer in physiotherapy at Brunel University in England. "They all want to discover something. Whether your vested interest is academic or entrepreneurial, there is an emphasis on discovery, but not on confirmation, not on rigorous replication."
Narbis' neurofeedback technology is based on work by Devon Greco's father, the late Domenic Greco. Domenic developed a patented brain-feedback device based on a NASA prototype that he used in psychotherapy with ADHD patients. A review of such neuro-feedback technology published last year in the journal Biological Psychology confirmed that the technique may work to reduce inattention, hyperactivity, and impulsiveness, but noted the small sample size and lack of placebo in many studies.
The review also addressed the "theta-beta ratio" on which Narbis' software is based, the measure of attention-related brainwaves developed by pioneering neurofeedback scientist Dr. Joel Lubar. According to research, this variable only affects 20 to 30 percent of ADHD children. So how the gadgets work remains unclear.
Narbis' marketing material, like that of many brain devices, makes claims both broad and specific. "By doing just two short training sessions a week, you can improve the overall performance of the brain," the website says. The company's promotional video adds, "Narbis can help you focus, sleep well, manage stress, and think clearly."
These claims are, of course, "falsifiable," as scientists say: testable hypotheses. But no such studies on the Narbis glasses have yet been done. The assertions are based on prior studies done by outside labs with similar setups, but not on the device the company is selling. The claims are, for now, more wishful marketing-speak than fact.
And while the FDA has approved commercial neurofeedback devices as safe (as long as they are not marketed to treat diseases), they don't have to meet any standard of effectiveness.
None of this means the device doesn't work, just that there is no way yet for consumers to know.
The problem, according to Brunel's O'Connell, starts with the bias toward positive results in science, along with hyperbolic terminology like "neuro-enhancement" and "brain boosting." New discoveries are published far more often than failures to reproduce previous results. These negative results, just as informative as successes, rarely see the light of day. Companies like Narbis have even less motivation to publish negative results.
"The things less incentivized are perhaps most important," O'Connell says. "When we [scientists] don't pay sufficient attention to the uncomfortable questions — low sample size, highly selected sample, loose exploratory statistics — then it isn't just the media who are responsible for hype."
"Of course, the idea of neurofeedback is incredibly intuitive and exciting, so it's no surprise that everyone wants to capitalize on it," says Todd Braver, an expert on cognitive control and a professor of psychology, neuroscience, and radiology at Washington University in St. Louis. "But we should be very wary of placebo effects — probably the most effective neurofeedback device there is: our belief system."
But that doesn't mean we should discourage companies like Narbis.
"I'm very happy for people to keep taking a crack at neurofeedback," says Braver. "That's what science is about anyway. What seem like crazy hare-brained ideas might actually work. But the main tenet of science is also: Show me the evidence. And we know what the history is with these 'neuroscience-inspired' products, software, gadgets: lots of claims and overblown arguments for support without really any direct evidence."
#science
» see original post http://theweek.com/articles/555637/glasses-read-mind-look-wild-west-brain-gadgets
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Saving fuel with software
Science Focus
original post »Energy efficiency isn't just a good idea from an environmental perspective; it makes business sense as well. But once companies commit to large hardware—say an aircraft or heavy machinery—there's often not a lot that can be done to improve the equipment's use of fuel. The primary option is to use the hardware as efficiently as possible.
That's gotten a lot easier over the last several years, primarily because of developments in electronics. Aircraft and trains now come equipped with GPS receivers that provide precise positional information, and these vehicles have processors sufficient to run sophisticated software if necessary. That software can then be used to control certain aspects of their operations to provide a more efficient trip.
We recently talked to Lucas Malta, who leads a team that helps develop transportation software for GE. He described two projects the group is working on, both focused on this exact problem—improving the use of fuel by large equipment.
Read 10 remaining paragraphs | Comments
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» see original post http://feeds.arstechnica.com/~r/arstechnica/science/~3/TTjahiK-bTI/
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Carina Nebula - Breathtaking Universe Square Sticker
Here's a great sheet of stickers featuring a beautiful image from deep space
tagged with: stlrnrsry, star clusters, galaxies, awesome astronomy pictures, constellation puppis, the stern, star nurseries, nebulae, outer space exploration, universe photographs, starfields, european southern observatory, eso, vista
The image, looking like a colourful cosmic ghost or a gigantic celestial Mandrill, contains the open clusters Haffner 18 (centre) and Haffner 19 (middle right: it is located inside the smaller pink region - the lower eye of the Mandrill), as well as vast areas of ionised gas.
The bright star at the centre of the largest pink region on the bottom of the image is HD 64315, a massive young star that is helping shaping the structure of the whole nebular region.
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Image code: stlrnrsry
ESO/J. Emerson/VISTA www.eso.org
Reproduced under the Creative Commons Attribution 3.0 Unported license.
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tagged with: stlrnrsry, star clusters, galaxies, awesome astronomy pictures, constellation puppis, the stern, star nurseries, nebulae, outer space exploration, universe photographs, starfields, european southern observatory, eso, vista
Galaxies, Stars and Nebulae series
A gorgeous set of oval stickers showing the area surrounding the stellar cluster NGC 2467, located in the southern constellation of Puppis ("The Stern"). With an age of a few million years at most, it is a very active stellar nursery, where new stars are born continuously from large clouds of dust and gas.The image, looking like a colourful cosmic ghost or a gigantic celestial Mandrill, contains the open clusters Haffner 18 (centre) and Haffner 19 (middle right: it is located inside the smaller pink region - the lower eye of the Mandrill), as well as vast areas of ionised gas.
The bright star at the centre of the largest pink region on the bottom of the image is HD 64315, a massive young star that is helping shaping the structure of the whole nebular region.
more items with this image
more items in the Galaxies, Stars and Nebulae series
Image code: stlrnrsry
ESO/J. Emerson/VISTA www.eso.org
Reproduced under the Creative Commons Attribution 3.0 Unported license.
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It's not all about aliens – listening project may unveil other secrets of the universe
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The Search for Extraterrestrial Intelligence (SETI) project got a $100 million boost this week from Russian billionaire Yuri Milner. While this may seem like a lot of money to spend on a nearly impossible task, many astronomers welcome the investment. The cash will go some way to help save some observatories from closure and allow astronomers to continue to use the facilities for astrophysics research alongside SETI.
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The Search for Extraterrestrial Intelligence (SETI) project got a $100 million boost this week from Russian billionaire Yuri Milner. While this may seem like a lot of money to spend on a nearly impossible task, many astronomers welcome the investment. The cash will go some way to help save some observatories from closure and allow astronomers to continue to use the facilities for astrophysics research alongside SETI.
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Gamma-ray Rain from 3C 279
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If gamma-rays were raindrops a flare from a supermassive black hole might look like this. Not so gently falling on the Fermi Gamma-ray Space Telescope from June 14 to June 16 the gamma-ray photons, with energies up to 50 billion electron volts, originated in active galaxy 3C 279 some 5 billion light-years away. Each gamma-ray "drop" is an expanding circle in the timelapse visualization, the color and maximum size determined by the gamma-ray's measured energy. Starting with a background drizzle, the sudden downpour that then trails off is the intense, high energy flare. The creative and calming presentation of the historically bright flare covers a 5 degree wide region of the gamma-ray sky centered on 3C 279.
Zazzle Space Gifts for young and old
Zazzle Space Gifts for young and old
Carina Nebula Hubble Space Wall Stickers
Here's a great wall decal featuring a beautiful image from deep space
tagged with: carina nebula, nebula, astronomy, stars, nasa, mystic mountain, outer space, deep space, nature, cool astronomy, star formation, milky way, hh 901, hh 902, esa, universe, hubble telescope, hubble space telescope, hubble photo, cosmos, astronomical, cosmology, space, natural, science, space picture, space image, nebula picture, cool astronomy photo, cool space photo, nebula photo, nebula image
Hubble telescope photograph of the Carina Nebula
This photo of the Carina Nebula was taken by the Hubble Space Telescope. It is reminiscent of a sci-fi/fantasy illustration, and shows an enormous mountainous pillar of dust and gas in rich orange tones, against a starlit deep blue background.
Credit: NASA, ESA, M. Livio and the Hubble 20th Anniversary Team (STScI)
You can personalise the design further if you'd prefer, such as by adding your name or other text, or adjusting the image - just click 'Customize it' to see all the options. IMPORTANT: If you choose a different sized version of the product, it's important to click Customize and check the image in the Design view to ensure it fills the area to the edge of the product, otherwise white edges may be visible.
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tagged with: carina nebula, nebula, astronomy, stars, nasa, mystic mountain, outer space, deep space, nature, cool astronomy, star formation, milky way, hh 901, hh 902, esa, universe, hubble telescope, hubble space telescope, hubble photo, cosmos, astronomical, cosmology, space, natural, science, space picture, space image, nebula picture, cool astronomy photo, cool space photo, nebula photo, nebula image
Hubble telescope photograph of the Carina Nebula
This photo of the Carina Nebula was taken by the Hubble Space Telescope. It is reminiscent of a sci-fi/fantasy illustration, and shows an enormous mountainous pillar of dust and gas in rich orange tones, against a starlit deep blue background.
Credit: NASA, ESA, M. Livio and the Hubble 20th Anniversary Team (STScI)
You can personalise the design further if you'd prefer, such as by adding your name or other text, or adjusting the image - just click 'Customize it' to see all the options. IMPORTANT: If you choose a different sized version of the product, it's important to click Customize and check the image in the Design view to ensure it fills the area to the edge of the product, otherwise white edges may be visible.
See more in my shop
If you like this product, you can find more like it in my store:
Click here to view all the other items with this design.
Click here to see a wide range of other astronomy & space designs.
»visit the AstronomyGiftShop store for more designs and products like this
Click to customize.
via Zazzle Astronomy market place
Star birth in Carina Nebula from Hubble's WFC3 det iPad Cases
Here's a great iPad case from Zazzle featuring a Hubble-related design. Maybe you'd like to see your name on it? Click to personalize and see what it's like!
tagged with: argo navis, astronomy, carina, celestial bodies, exploration, milky way, natural sciences, natural world, nebula, ngc 3372, nobody, outer space, physical science, sciences, space exploration and research, stars
ImageID: 42-23286264 / STScI / NASA/Corbis / Star birth in Carina Nebula from Hubble's WFC3 detector
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The Zazzle Promise: We promise 100% satisfaction. If you don't absolutely love it, we'll take it back!
tagged with: argo navis, astronomy, carina, celestial bodies, exploration, milky way, natural sciences, natural world, nebula, ngc 3372, nobody, outer space, physical science, sciences, space exploration and research, stars
ImageID: 42-23286264 / STScI / NASA/Corbis / Star birth in Carina Nebula from Hubble's WFC3 detector
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The Zazzle Promise: We promise 100% satisfaction. If you don't absolutely love it, we'll take it back!
Keeping the smells of onions, garlic and other stinky foods under wraps
original post »
#materials
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Some of the world’s most popular foods and seasonings can also be the smelliest — think garlic, onions,
The post Keeping the smells of onions, garlic and other stinky foods under wraps has been published on Technology Org.
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What makes fireflies glow?
original post »
#materials
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As fireflies are delighting children across the country with their nighttime displays, scientists are closing in on a
The post What makes fireflies glow? has been published on Technology Org.
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Sandia tamper-detecting seal is tough to fool
original post »
#materials
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A critical area of security is ensuring that something inside a container stays there. Sandia National Laboratories has
The post Sandia tamper-detecting seal is tough to fool has been published on Technology Org.
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Graphene oxide for Lithium-Sulfur batteries
more »
In the mid-term, lithium sulfur (Li-S) will be the most likely successor to LIBs. At the moment, Li-S batteries suffer from poor cycle stability and low rates, withholding a revolution in battery technology. In this respect, graphene oxide (GO) has arisen as an interesting addition to sulfur cathodes, substantially improving the performance of Li-S batteries. Here we review the technology of using GO in Li-S batteries and the advantages that it offers.
Principle of operation of Li-S batteries
Li-S cells typically consist of a lithium anode and a carbon-sulfur cathode, separated by an electrolyte. During discharge, lithium ions from the anode flow through the electrolyte to the cathode, there reacting with sulfur to form polysulfides. Energy is released during the lithium-sulfur reaction. During charging, the reverse occurs, replacing lithium ions in the anode and sulfur in the cathode.
The problem with first-generation Li-S batteries is that the polysulfide drifts away from the cathode and dissolves in the electrolyte, leading to irreversible loss of the active sulfur and a consequent reduction in cycle stability. Cycle stability over at least 1,000 cycles is imperative for commercial batteries. The polysulfides that reach the anode react with the lithium, coating the anode with a passive layer of Li2S, which inhibits anode performance. Graphene-based cathodes emerge as an excellent solution to these challenges and have resulted in tremendous performance improvements.
Graphene-based cathodes
There are numerous ways in which graphene has been applied as a cathode material in Li-S batteries.
Most simply, the conducting graphene electrode can be coated with elemental sulfur, for example by mechanical mixing. A more stable electrode is obtained with a chemical method which starts from GO. Li-S batteries with such cathodes perform better because the graphene electrode conducts better than traditional graphite ones, but the sulfur at the cathode surface is still exposed to the electrolyte and can drift away.
A second approach is to embed sulfur into the graphene electrode, by mixing it with thermally exfoliated graphene. The sulfur then sits in a graphene matrix, which is additionally stabilized by coating with reduced GO (rGO). Coating the matrix with rGO was shown to increase discharge capacity retention by 50%.
Another interesting approach is to coat sulfur microparticles with graphene. After the reaction, the graphene “blanket” prevents polysulfides from detaching from the cathode and flowing to the electrolyte. This approach, which also starts from GO, improves Li-S battery cycle stability to 86% after 60 cycles, more than any other method.
Finally, embedding sulfur particles in a graphene hydrogel and directly using synthesized graphene/sulfur paper electrodes have also resulted in Li-S batteries superior to current technology.
Conclusions
Graphene, and in particular graphene oxide, has shown to be a valuable material for solving the hardest challenges presented in lithium-sulfur batteries. Graphenea has continuously expanded its GO product line, now featuring volumes ranging from just 250 ml up to 2,5 l. The company's catalog also holds reduced graphene oxide in powder form and graphene oxide films obtained with vacuum filtration, all ready to be tested in novel cathode designs or mass-produced for the applications described above. Last month, Graphenea was awarded €2.5 million for construction of a production plant, which will expand production capacity by 200 times. The funding was approved by the European Commission, as part of the Horizon 2020 program “SME Instrument”. The new production plant should be finished by the end of 2017, accelerating the growth of Graphenea and strengthening its position as a global leader in graphene materials.
References:
J. Mater. Chem. A, 2015,3, 7241-7247
J. Mater. Chem. A, 2014, 2, 33–47
via Graphenea
This article was first published at IDTechEx.
Rapid development of mobile communication devices, electric vehicles, and other energy-hungry machines detached from landlines is stretching the capabilities of current battery technology. Lithium ion batteries (LIBs) are today’s dominant technology due to their excellent cycle stability and good charge/discharge rates. However, the energy density packed in LIBs has reached its peak and is becoming a limiting factor for widespread use of mobile energy consumers. Energy density translates into charging speed, which is highly sought after by consumers.
Potential replacements for LIBs are a hot area of research, with energy density and cost the main gauging parameters. The chart below depicts the state of the art (in blue), with LIB leading current technology with energy density equivalent to 160 km (100 mile) electric vehicle independence. At the theoretical maximum, LIBs could give 200 km (130 miles) of independence to EVs, before the need for recharging. In the order of increasing energy density, battery technologies that are being considered as successors of LIBs are zinc-air, lithium-sulfur (Li-S), and lithium-air.
In the mid-term, lithium sulfur (Li-S) will be the most likely successor to LIBs. At the moment, Li-S batteries suffer from poor cycle stability and low rates, withholding a revolution in battery technology. In this respect, graphene oxide (GO) has arisen as an interesting addition to sulfur cathodes, substantially improving the performance of Li-S batteries. Here we review the technology of using GO in Li-S batteries and the advantages that it offers.
Principle of operation of Li-S batteries
Li-S cells typically consist of a lithium anode and a carbon-sulfur cathode, separated by an electrolyte. During discharge, lithium ions from the anode flow through the electrolyte to the cathode, there reacting with sulfur to form polysulfides. Energy is released during the lithium-sulfur reaction. During charging, the reverse occurs, replacing lithium ions in the anode and sulfur in the cathode.
The problem with first-generation Li-S batteries is that the polysulfide drifts away from the cathode and dissolves in the electrolyte, leading to irreversible loss of the active sulfur and a consequent reduction in cycle stability. Cycle stability over at least 1,000 cycles is imperative for commercial batteries. The polysulfides that reach the anode react with the lithium, coating the anode with a passive layer of Li2S, which inhibits anode performance. Graphene-based cathodes emerge as an excellent solution to these challenges and have resulted in tremendous performance improvements.
Graphene-based cathodes
There are numerous ways in which graphene has been applied as a cathode material in Li-S batteries.
Most simply, the conducting graphene electrode can be coated with elemental sulfur, for example by mechanical mixing. A more stable electrode is obtained with a chemical method which starts from GO. Li-S batteries with such cathodes perform better because the graphene electrode conducts better than traditional graphite ones, but the sulfur at the cathode surface is still exposed to the electrolyte and can drift away.
A second approach is to embed sulfur into the graphene electrode, by mixing it with thermally exfoliated graphene. The sulfur then sits in a graphene matrix, which is additionally stabilized by coating with reduced GO (rGO). Coating the matrix with rGO was shown to increase discharge capacity retention by 50%.
Another interesting approach is to coat sulfur microparticles with graphene. After the reaction, the graphene “blanket” prevents polysulfides from detaching from the cathode and flowing to the electrolyte. This approach, which also starts from GO, improves Li-S battery cycle stability to 86% after 60 cycles, more than any other method.
Finally, embedding sulfur particles in a graphene hydrogel and directly using synthesized graphene/sulfur paper electrodes have also resulted in Li-S batteries superior to current technology.
Conclusions
Graphene, and in particular graphene oxide, has shown to be a valuable material for solving the hardest challenges presented in lithium-sulfur batteries. Graphenea has continuously expanded its GO product line, now featuring volumes ranging from just 250 ml up to 2,5 l. The company's catalog also holds reduced graphene oxide in powder form and graphene oxide films obtained with vacuum filtration, all ready to be tested in novel cathode designs or mass-produced for the applications described above. Last month, Graphenea was awarded €2.5 million for construction of a production plant, which will expand production capacity by 200 times. The funding was approved by the European Commission, as part of the Horizon 2020 program “SME Instrument”. The new production plant should be finished by the end of 2017, accelerating the growth of Graphenea and strengthening its position as a global leader in graphene materials.
References:
J. Mater. Chem. A, 2015,3, 7241-7247
J. Mater. Chem. A, 2014, 2, 33–47
via Graphenea
New Horizons captures two of Pluto's smaller moons
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Pluto's moon Nix, imaged by the New Horizons Ralph instrument, has a reddish spot that has attracted the interest of mission scientists. Pluto's small, irregularly shaped moon Hydra is revealed in another image. Features as small as 0.7 miles (1.2 kilometers) are visible on Hydra, which measures 34 miles (55 kilometers) in length.
via Science Daily
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Pluto's moon Nix, imaged by the New Horizons Ralph instrument, has a reddish spot that has attracted the interest of mission scientists. Pluto's small, irregularly shaped moon Hydra is revealed in another image. Features as small as 0.7 miles (1.2 kilometers) are visible on Hydra, which measures 34 miles (55 kilometers) in length.
via Science Daily
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NASA's New Horizons finds second mountain range in Pluto's 'heart'
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A newly discovered mountain range lies near the southwestern margin of Pluto's Tombaugh Regio (Tombaugh Region), situated between bright, icy plains and dark, heavily-cratered terrain.
via Science Daily
Zazzle Space Exploration market place
A newly discovered mountain range lies near the southwestern margin of Pluto's Tombaugh Regio (Tombaugh Region), situated between bright, icy plains and dark, heavily-cratered terrain.
via Science Daily
Zazzle Space Exploration market place
Vintage Astronomy, Celestial Planisphere Star Map Poster
Here's a great poster featuring a beautiful image from deep space
tagged with: antique, constellations, retro, planisphere, americana, nostalgia, nostalgic, vintage illustration, celestial map, star chart, antique celestial
Vintage illustration astronomy and celestial star chart map by Carel Allard (1648-1709), a 17th century Dutch cartographer. This antique planisphere features constellations in the night sky including some signs of the zodiac and other creatues and figures in mythology, the sun, moon and earth, as well as other planets (Mars, Mercury, Venus, Jupiter and Saturn), 1706. Planisphaerii coelestis hemisphaerium meridionale.
»visit the YesterdayCafe store for more designs and products like this
Click to customize with size, paper type etc.
via Zazzle Astronomy market place
tagged with: antique, constellations, retro, planisphere, americana, nostalgia, nostalgic, vintage illustration, celestial map, star chart, antique celestial
Vintage illustration astronomy and celestial star chart map by Carel Allard (1648-1709), a 17th century Dutch cartographer. This antique planisphere features constellations in the night sky including some signs of the zodiac and other creatues and figures in mythology, the sun, moon and earth, as well as other planets (Mars, Mercury, Venus, Jupiter and Saturn), 1706. Planisphaerii coelestis hemisphaerium meridionale.
»visit the YesterdayCafe store for more designs and products like this
Click to customize with size, paper type etc.
via Zazzle Astronomy market place
Trifid Nebula, Messier 16 Square Sticker
Here's a great sheet of stickers featuring a beautiful image from deep space
tagged with: breathtaking astronomy images, star forming nebulae, trfdnbl, star nurseries, galaxies, nebulae, star factory, trifid nebula, european southern observatory, clusters of stars, factories for stars, eso, vista
Galaxies, Stars and Nebulae series A fantastic picture from our universe featuring the massive star factory known as the Trifid Nebula.
It was captured in all its glory with the Wide-Field Imager camera attached to the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in northern Chile.
So named for the dark dust bands that trisect its glowing heart, the Trifid Nebula is a rare combination of three nebulae types that reveal the fury of freshly formed stars and point to more star birth in the future. The field of view of the image is approximately 13 x 17 arcminutes.
It's an awe-inspiring, breathtaking image that reveals some of the wonder that is our universe.
more items with this image
more items in the Galaxies, Stars and Nebulae series
image code: trfdnbl
ESO/J. Emerson/VISTA www.eso.org
Reproduced under the Creative Commons Attribution 3.0 Unported license.
»visit the HightonRidley store for more designs and products like this
Click to customize.
via Zazzle Astronomy market place
tagged with: breathtaking astronomy images, star forming nebulae, trfdnbl, star nurseries, galaxies, nebulae, star factory, trifid nebula, european southern observatory, clusters of stars, factories for stars, eso, vista
Galaxies, Stars and Nebulae series A fantastic picture from our universe featuring the massive star factory known as the Trifid Nebula.
It was captured in all its glory with the Wide-Field Imager camera attached to the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in northern Chile.
So named for the dark dust bands that trisect its glowing heart, the Trifid Nebula is a rare combination of three nebulae types that reveal the fury of freshly formed stars and point to more star birth in the future. The field of view of the image is approximately 13 x 17 arcminutes.
It's an awe-inspiring, breathtaking image that reveals some of the wonder that is our universe.
more items with this image
more items in the Galaxies, Stars and Nebulae series
image code: trfdnbl
ESO/J. Emerson/VISTA www.eso.org
Reproduced under the Creative Commons Attribution 3.0 Unported license.
»visit the HightonRidley store for more designs and products like this
Click to customize.
via Zazzle Astronomy market place
Why we live on Earth and not Venus
more »
Compared to its celestial neighbors Venus and Mars, Earth is a pretty habitable place. So how did we get so lucky? A new study sheds light on the improbable evolutionary path that enabled Earth to sustain life.
via Science Daily
Zazzle Space Exploration market place
Compared to its celestial neighbors Venus and Mars, Earth is a pretty habitable place. So how did we get so lucky? A new study sheds light on the improbable evolutionary path that enabled Earth to sustain life.
via Science Daily
Zazzle Space Exploration market place
Simulations lead to design of near-frictionless material
more »
Scientists used the Mira supercomputer to identify and improve a new mechanism for eliminating friction, which fed into the development of a hybrid material that exhibited superlubricity at the macroscale for the first time. Researchers helped enable the groundbreaking simulations by overcoming a performance bottleneck that doubled the speed of the team's code.
via Science Daily
Scientists used the Mira supercomputer to identify and improve a new mechanism for eliminating friction, which fed into the development of a hybrid material that exhibited superlubricity at the macroscale for the first time. Researchers helped enable the groundbreaking simulations by overcoming a performance bottleneck that doubled the speed of the team's code.
via Science Daily
Star birth in Carina Nebula from Hubble's WFC3 det iPad Folio Case
Here's a great iPad case from Zazzle featuring a Hubble-related design. Maybe you'd like to see your name on it? Click to personalize and see what it's like!
tagged with: argo navis, astronomy, carina, celestial bodies, exploration, milky way, natural sciences, natural world, nebula, ngc 3372, nobody, outer space, physical science, sciences, space exploration and research, stars
ImageID: 42-23286264 / STScI / NASA/Corbis / Star birth in Carina Nebula from Hubble's WFC3 detector
»visit the corbisimages store for more designs and products like this
The Zazzle Promise: We promise 100% satisfaction. If you don't absolutely love it, we'll take it back!
tagged with: argo navis, astronomy, carina, celestial bodies, exploration, milky way, natural sciences, natural world, nebula, ngc 3372, nobody, outer space, physical science, sciences, space exploration and research, stars
ImageID: 42-23286264 / STScI / NASA/Corbis / Star birth in Carina Nebula from Hubble's WFC3 detector
»visit the corbisimages store for more designs and products like this
The Zazzle Promise: We promise 100% satisfaction. If you don't absolutely love it, we'll take it back!
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