Rice University researchers have determined from first-principle calculations that carbyne would be the strongest material yet discovered. The carbon-atom chains would be difficult to make but would be twice as strong as two-dimensional graphene sheets. (Image Credit: Vasilii Artyukhov/Rice University)
Carbyne will be the strongest of a new class of microscopic materials if and when anyone can make it in bulk.
If they do, they’ll find carbyne nanorods or nanoropes have a host of remarkable and useful properties, as described in a new paper by Rice University theoretical physicist Boris Yakobson and his group. The paper appears this week in the American Chemical Society journal ACS Nano.
Carbyne is a chain of carbon atoms held together by either double or alternating single and triple atomic bonds. That makes it a true one-dimensional material, unlike atom-thin sheets of graphene that have a top and a bottom or hollow nanotubes that have an inside and outside.
According to the portrait drawn from calculations by Yakobson and his group:
- Carbyne’s tensile strength – the ability to withstand stretching – surpasses “that of any other known material” and is double that of graphene. (Scientists had already calculated it would take an elephant on a pencil to break through a sheet of graphene.)
- It has twice the tensile stiffness of graphene and carbon nanotubes and nearly three times that of diamond.
- Stretching carbyne as little as 10 percent alters its electronic band gap significantly.
- If outfitted with molecular handles at the ends, it can also be twisted to alter its band gap. With a 90-degree end-to-end rotation, it becomes a magnetic semiconductor.
- Carbyne chains can take on side molecules that may make the chains suitable for energy storage.
- The material is stable at room temperature, largely resisting crosslinks with nearby chains.
That’s a remarkable set of qualities for a simple string of carbon atoms, Yakobson said.
Archive for the ‘Physics’ Category
Posted by Xeno on October 10, 2013
Posted by Xeno on September 28, 2013
In an advance that could dramatically shrink particle accelerators for science and medicine, researchers used a laser to accelerate electrons at a rate 10 times higher than conventional technology in a nanostructured glass chip smaller than a grain of rice.
The achievement was reported today inNature by a team including scientists from the U.S. Department of Energy’s (DOE) SLAC National Accelerator Laboratory and Stanford University.
“We still have a number of challenges before this technology becomes practical for real-world use, but eventually it would substantially reduce the size and cost of future high-energy particle colliders for exploring the world of fundamental particles and forces,” said Joel England, the SLAC physicist who led the experiments. “It could also help enable compact accelerators and X-ray devices for security scanning, medical therapy and imaging, and research in biology and materials science.”
Because it employs commercial lasers and low-cost, mass-production techniques, the researchers believe it will set the stage for new generations of “tabletop” accelerators.
At its full potential, the new “accelerator on a chip” could match the accelerating power of SLAC’s 2-mile-long linear accelerator in just 100 feet, and deliver a million more electron pulses per second.
This initial demonstration achieved an acceleration gradient, or amount of energy gained per length, of 300 million electronvolts per meter. That’s roughly 10 times the acceleration provided by the current SLAC linear accelerator.
Posted by Xeno on September 25, 2013
Working with colleagues at the Harvard-MIT Center for Ultracold Atoms, a group led by Harvard Professor of Physics Mikhail Lukin and MIT Professor of Physics Vladan Vuletic have managed to coax photons into binding together to form molecules – a state of matter that, until recently, had been purely theoretical. The work is described in a September 25 paper in Nature.
The discovery, Lukin said, runs contrary to decades of accepted wisdom about the nature of light. Photons have long been described as massless particles which don’t interact with each other – shine two laser beams at each other, he said, and they simply pass through one another.
“Photonic molecules,” however, behave less like traditional lasers and more like something you might find in science fiction – the light saber.
“Most of the properties of light we know about originate from the fact that photons are massless, and that they do not interact with each other,” Lukin said. “What we have done is create a special type of medium in which photons interact with each other so strongly that they begin to act as though they have mass, and they bind together to form molecules. This type of photonic bound state has been discussed theoretically for quite a while, but until now it hadn’t been observed.
This is a good follow up about the light saber hype.
A team of physicists from MIT and Harvard have created a new form of matter by binding photons into molecules. The team compared the way these new molecules interact to lightsabers, and the Internet went bonkers. Pump the brakes, everyone. They have not created a lightsaber. Here’s what happened.
Photons don’t interact with each other. If you shine two lasers at one another, the beams can pass through one another completely unaffected. If you try to pass two lightsabers through one another, well, you get Star Wars. The “blades” of the lightsabers do interact by clashing together. They are essentially solid light.
The “photonic molecules” created by the team at the Harvard-MIT Center of Ultracold Atoms interact in a similar way. They don’t simply pass through each other like typical photons. They bump up against each other and clash in a way that can fairly be described as lightsaber-esque if that were a word.
It’s incredible that there’s a new form of matter, and from what we’ve read comparing the interaction of these molecules to lightsabers doesn’t seem like a bad description. Then we saw the headlines that resulted:
No, they didn’t. They created a new form of matter that behaves like a LIGHTSABER.
They have not. Although the photonic molecules interact in a way that compares to lightsabers, that doesn’t mean the molecules are themselves the stuff of lightsabers, or that, even if they were, there is a way to scale that up into an actual working prototype.
Et tu, Wired?
We’d all love to see lightsabers become a reality so we can have our dads chop our hands off and get robot hands, but it’s an unfounded jump to say that photonic molecules equal lightsabers, so please stop doing it. Instead, let’s all focus on the exciting prospects photonic molecules have for quantum computing. …
Posted by Xeno on September 20, 2013
It might be called a shock finding. Coating plastic or rubber materials with antioxidants such as vitamin E stops static charge from building up on the polymer’s surface, chemists report today. The discovery could prove a cheap solution to problems such as dust clinging to plastic, static electric shocks, or the sparks that damage television circuits and fry computer motherboards.
Children can have fun with static electricity – when they rub balloons on their hair, the rubber and hair stick together because of the attraction between transferred charged particles. But static charge that builds up on industrial components, such as plastic fuel filters on cars or inside semiconductor parts, can lead to potentially dangerous electric sparks and a build-up of dust.
The puzzle with static electricity, explains Bartosz Grzybowski, a physical chemist at Northwestern University in Evanston, Illinois, is that although charged particles should repel each other when they land on an insulating surface, making them spread evenly across a material and leak back into the air, they actually form stable, long-lived clumps. This leads to the build-up of large amounts of tightly confined static charge, enough to abruptly discharge when a conductive path becomes available: for example, shooting through a human body to a metal railing, or sparking through air like a miniature lightning bolt.
I find this interesting due to claims that grounding (for example by going barefoot) can reduce oxidative stress and heal disease.
Posted by Xeno on September 19, 2013
Via Alex Tabarrok,Quanta magazine reports on a decades-long effort that has recently produced a radically simplified way of calculating quantum interactions. Instead of adding up millions or billions of terms, you simply sum the volumes of the pieces of a multi-dimensional object called a “positive Grassmannian.” Its inventors call this object an amplituhedron:
The amplituhedron is not built out of space-time and probabilities; these properties merely arise as consequences of the jewel’s geometry….Encoded in its volume are the most basic features of reality that can be calculated, “scattering amplitudes,” which represent the likelihood that a certain set of particles will turn into certain other particles upon colliding.
….The 60-year-old method for calculating scattering amplitudes – a major innovation at the time – was pioneered by the Nobel Prize-winning physicist Richard Feynman….”The number of Feynman diagrams is so explosively large that even computations of really simple processes weren’t done until the age of computers,” Bourjaily said….In 1986, it became apparent that Feynman’s apparatus was a Rube Goldberg machine.
….Arkani-Hamed and Trnka discovered that the scattering amplitude equals the volume of a brand-new mathematical object – the amplituhedron. The details of a particular scattering process dictate the dimensionality and facets of the corresponding amplituhedron. The pieces of the positive Grassmannian that were being calculated with twistor diagrams and then added together by hand were building blocks that fit together inside this jewel, just as triangles fit together to form a polygon.
….”They are very powerful calculational techniques, but they are also incredibly suggestive,” Skinner said. “They suggest that thinking in terms of space-time was not the right way of going about this.”
…Aside from making calculations easier, it’s possible that the nature of the amplituhedron will provide new insights into what the fundamental laws of the universe really are. Or it might turn out to be a red herring. Who knows?…http://www.motherjones.com/kevin-drum/2013/09/space-time-illusion-amplituhedron
The amplituhedron is my space-time ship.
Scientists shatter world record: Thinnest ever sheet of glass created at just ONE molecule thick … and all because of an accidental discovery
Posted by Xeno on September 13, 2013
An accidental discovery has led to the creation of the world’s thinnest sheet of glass – at just one molecule thick.
The ‘pane’ of glass is so impossibly thin that its individual silicon and oxygen atoms are clearly visible using a microscope.
The discovery may someday lead to a defect-free, ultra-thin material that could improve the performance of processors in computers and smartphones.
The glass was identified by chance in the lab of David Muller, professor of applied and engineering physics at Cornell University.
Professor Muller had been making graphene, a two-dimensional sheet of carbon atoms, in a chicken wire crystal formation.
He noticed some ‘muck’ on the graphene, and when he took a closer look, found it to be made up of the elements of everyday glass; silicon and oxygen.
‘When the first images came up on the computer screen we were just blown away,’ he told MailOnline.
‘The mystery atoms were the elements of everyday glass, silicon and oxygen.
‘But more amazing, their arrangement looked exactly like the cartoons proposed 81 years ago as to how atoms in a glass might be arranged so that it would be stable.
‘And here, for the first time, we were actually seeing that.’
It took the research team another year to understand how the glass might have grown.
They concluded that an air leak had caused the copper to react with the quartz, also made of silicon and oxygen.
Posted by Xeno on August 28, 2013
A popcorn kernel is a cereal grain seed. It is made up of four major physical structures:
1 The Pericarp seed coat or outer hull: a hard outer thin covering.
2 The Endosperm: starchy part that forms the bulk of the kernel and consists almost entirely of starch along with smaller amounts of protein, fat, minerals and water. This water plays an important role in the popping process of popcorn.
3 The Germ embryo: The rudimentary partially developed plantlet within the seed. This is the structure that develops and grows into a new plant when it is planted.
4 Tip Cap: the part where the kernel joins attaches to the cob.
When the kernel is heated to about 400 degrees Fahrenheit the small amount of water 13-14% stored inside the starchy endosperm turns into vapor steam causing it to expand about 40 or 50 times its original size. As the water steam expands it puts pressure against the hard starch in the endosperm causing it to become inflated. Eventually, this causes the pericarp of the kernel to give way to the pressure from the built up steam causing it to explode pop as it flips inside out allowing the steam to escape and expose the soft white fluffy starch known as popcorn.
However, in order for popcorn to pop successfully, there must be certain ideal factors: The amount of moisture water in the kernel must be between 13 to 14 percent. Although popcorn are usually harvested when the moisture content is between 16-19% by mass, they are carefully cured or dried until the ideal moisture content is reached. Too little moisture and there would not be enough steam to carry out the popping process and if there is too much moisture, the popcorn will crack prematurely exposing a dense sphere with the starch not properly cooked rather than the ideal soft white fluffy popcorn. The pericarp of the kernel must have high mechanical strength. That is, it must be very strong tough. This is necessary to withstand retain the steam pressure buildup until it reaches the ideal pressure where the starch is cooked and it is strong enough to burst the strong pericarp wall of the kernel at the right time exposing the soft, white and fluffy popcorn. The pericarp must not contain any cracks or any damage. If it does, then the steam will escape when it is heated preventing the build up of steam pressure that is needed to burst the pericarp of the kernel properly. The temperature must be above 300 degrees F for the popcorn to pop. Popcorn has to be at a certain temperature about 400 degrees F so that it is possible for the steam pressure inside the kernel to buildup to the point where starch is properly cooked and it can pop burst the strong outer casing pericarp of the kernel.
Posted by Xeno on August 27, 2013
Researchers confirm the existence of this synthetic element in a new accelerator study. Will it be enough to give ununpentium official recognition and a new name?At the bottom right corner of the periodic table of elements, there are a handful of boxes that illustrators often color gray. The International Union of Pure and Applied Chemistry leaves out those boxes altogether, so that their periodic table looks a bit gap-toothed. The boxes are for elements that the IUPAC hasn’t yet confirmed actually exist.
Now, a new set of experiments backs up the discovery of one of those elements. An international team of physicists has synthesized an element with 115 protons in the GSI accelerator in Germany. This isn’t the first time a research group has synthesized the element, which has the temporary name of ununpentium (Latin for one-one-five, plus “-ium.”) A team of Russian and U.S. scientists first made ununpentium in the early 2000s and published a paper about it in 2006. However, at the time, the IUPAC didn’t consider that enough evidence to officially recognize-or name-ununpentium. The new GSI studies are another step toward official recognition.
Why do we say that people “synthesized” or “made” ununpentium, instead of saying people “found” it? Well, like other super-heavy elements, ununpentium can only exist when people perform experiments to create it. It’s an entirely synthetic element (ununpentium : elements :: polyester : fabrics?). You can’t just cook it up in any lab, either. The creation of elements heavier than uranium, which is the heaviest element to occur naturally on Earth and contains 92 protons, requires fusion reactions, nuclear reactions, or other highly specialized chemistry. Before ununpentium, the GSI accelerator had created six synthetic elements with more protons than uranium.
To make ununpentium, the team of physicists working at GSI bombarded a thin film of americium-another synthetic element, with 95 protons-with calcium ions, which have 20 protons each. The bombardment fuses the nuclei of the americium atoms with the nuclei of the calcium atoms to make a new, single, 115-proton nucleus. (See the very educational GIF on GSI’s “new elements” webpage.) Like all super-heavy, synthetic elements, ununpentium decays quickly. Atoms of ununpentium that researchers made for the 2006 announcement lasted just 30 to 80 milliseconds.
According to Lund University in Sweden, IUPAC members will now review the new confirmation of the 2006 work and decide whether it’s enough to merit official recognition for ununpentium. Lund researchers led the recent ununpentium experiments done at GSI. Meanwhile, the Lund team has published its findings in the journalPhysical Review Letters.
Besides confirming cool theories in chemistry, work on synthetic elements helps researchers learn more about the process of fission in general, according to the U.S.” Lawrence Livermore National Laboratory. You’re unlikely to see ununpentium in even the most advanced gizmos of the future, however. So far, scientists have found practical applications only for synthetic elements with 100 or so protons or fewer. …
This is particularly interesting to UFO buffs since 115 is the element that was said to have anti-gravity properties.
Element 115, the key to understanding how the ultra-secret “Black World” has created aircraft capable of manipulating gravity and space/time, has been identified … The reactor found in the alien craft at S4, as widely mentioned by physicist Robert Lazar is primarily based on a superheavy element with an atomic number of 115. Element 115 will be designated as “Ununpentium” according to IUPAC guidelines.
Bob Lazar stated that the “Sport Model” Flying Disc amplified the “Strong Nuclear Force” of Element 115 (UnUnPentium or UUP) to generate the gravity field for “Space-Time Compression.” Bob also stated that the U.S. Government had 500 pounds of Element 115 in their possession. The raw Element 115 was given to the U.S. Goverment at S4 by the Reticulan EBEs in the form of discs. …
Bob Lazar stated that the … fuel and gravity source in the “Sport Model” Flying Disc was stable. On February 2, 2004, scientists at the Lawrence Livermore National Laboratory, in collaboration with researchers from the Joint Institute for Nuclear Research in Russia (JINR), announced that they discovered two new super-heavy elements, Element 113 and Element 115. The Isotope of Element 115, produced by bombarding an Americium-243 (95Am243) nucleus with a Calcium-48 (20Ca48) nucleus, rapidly decayed to Element 113. then continued to decay until a meta-stable isotope was obtained. …
The following reactions are the actual reactions that took place in the laboratory by bombarding Americium-243 with Calcium-48, which resulted in the two Isotopes of Element 115, indicated below, being identified.
95Am243 + 20Ca48 → 115UUP288 + 30n1 115UUP288 → 113UUT284 + 2He4 → …
95Am243 + 20Ca48 → 115UUP287 + 40n1 115UUP287 → 113UUT283 + 2He4 → …
The maximum theoretical atomic mass isotope of Element 115 that could be produced in the reaction, above, 115UUP291, would only have 176 neutrons in its nucleus. This isotope of Element 115 is shy 8 neutrons from containing the magic number of 184 neutrons. The two actual isotopes of Element 115 produced by this reaction, 115UUP288 and 115UUP287 contain 173 neutrons, shy 11 neutrons from the magic number of 184, and 172 neutrons, shy 12 neutrons from the magic number of 184, respectively.
This latest scientific breakthrough, however, provides significant credibility to Bob Lazar’s claims rather than discrediting his claims. Bob Lazar’s Element 115 discs used to make the wedge for the “Sport Model” Flying Disc Anti-Matter Reactor would have to have been the isotope of Element 115 containing the magic number of 184 neutrons, therefore, having an atomic mass of 299. The nuclear configuration of this isotope of Element 115 would be identical to the nuclear configuration of the only known stable isotope of Element 83, Bismuth, 83Bi209, containing the magic number of 126 neutrons, except that the Element 115 isotope would have one more energy level completely filled with protons and neutrons. 82 protons and 114 protons are magic numbers for protons because 82 protons completely fill 6 proton energy levels and 114 protons completely fill 7 proton energy levels. The 83rd proton for Bismuth is a lone proton in the 7th proton energy level and the 115th proton for Element 115 is the lone proton in the 8th proton energy level. 126 neutrons completely fill 7 neutron energy levels and 184 neutrons completely fill 8 neutron energy levels. Refer to the Nucleon Energy Level Table for Bismuth and Element 115, below, for the nuclear configurations of Bismuth and Element 115. This stable isotope of Bismuth, Element 83, has very unique gravitational characteristics. Refer to the Henry William Wallace Patent: U.S. Patent 3,626,605, “Method and Apparatus for Generating a Secondary Gravitational Force Field.”
How do you weigh 500 lbs of a material with anti-gravity properties?
Posted by Xeno on August 14, 2013
… Every now and again, cosmologists decide that the universe needs a rethink. For example, for the past century, they have likened it to an inflating balloon, decorated with galaxies. Now one theoretical physicist has pricked this textbook idea by coming up with an heretical suggestion – namely, that the universe is not expanding at all.
The idea that the universe is unchanging – a constant backdrop that alters only with our parochial view of the heavens – was long ago consigned to the dustbin, thanks to the work of astronomers such as Edwin Hubble in the 1920s.
Hubble was based at Mount Wilson in Los Angeles County, where the 100-inch Hooker Telescope, then the most powerful in the world, had just been completed. He used it to analyse the light that the constituent atoms of galaxies emitted or absorbed, which comes in characteristic colours, or frequencies. He knew these frequencies would appear shifted towards the red end of the spectrum if the galaxies were moving away from us, just as we hear the pitch of a police siren drop as it zooms past.
Sure enough, the telescope revealed that most galaxies exhibit such a “red shift” – and, moreover, that the extent of the red shift became greater as the galaxies became more distant. The only conclusion was that the universe was expanding. From the point of view of the inhabitants of any one of its galaxies, it looked as if your neighbours were rushing away from you.
This idea might sound humdrum. But it marked the dawn of a revolutionary new view of the nature, origin, and fate of the universe, suggesting that billions of years ago, the universe must have been far denser than it is now, and that it started in a Big Bang.
Now that conventional thinking has been turned on its head in a paper by Prof Christof Wetterich at the University of Heidelberg in Germany. He points out that the tell-tale light emitted by atoms is also governed by the masses of their constituent particles, notably their electrons. The way these absorb and emit light would shift towards the blue part of the spectrum if atoms were to grow in mass, and to the red if they lost it.
Because the frequency or “pitch” of light increases with mass, Prof Wetterich argues that masses could have been lower long ago. If they had been constantly increasing, the colours of old galaxies would look red-shifted – and the degree of red shift would depend on how far away they were from Earth. “None of my colleagues has so far found any fault [with this],” he says.
Although his research has yet to be published in a peer-reviewed publication, Nature reports that the idea that the universe is not expanding at all – or even contracting – is being taken seriously by some experts, such as Dr HongSheng Zhao, a cosmologist at the University of St Andrews who has worked on an alternative theory of gravity.
“I see no fault in [Prof Wetterich’s] mathematical treatment,” he says. “There were rudimentary versions of this idea two decades ago, and I think it is fascinating to explore this alternative representation of the cosmic expansion, where the evolution of the universe is like a piano keyboard played out from low to high pitch.”
Prof Wetterich takes the detached, even playful, view that his work marks a change in perspective, with two different views of reality: either the distances between galaxies grow, as in the traditional balloon picture, or the size of atoms shrinks, increasing their mass. Or it’s a complex blend of the two. One benefit of this idea is that he is able to rid physics of the singularity at the start of time, a nasty infinity where the laws of physics break down. Instead, the Big Bang is smeared over the distant past: the first note of the ”cosmic piano’’ was long and low-pitched.
Harry Cliff, a physicist working at CERN who is the Science Museum’s fellow of modern science, thinks it striking that a universe where particles are getting heavier could look identical to one where space/time is expanding. “Finding two different ways of thinking about the same problem often leads to new insights,” he says. “String theory, for instance, is full of ‘dualities’ like this, which allow theorists to pick whichever view makes their calculations simpler.”
If this idea turns out to be right – and that is a very big if – it could pave the way for new ways to think about our universe. …
Posted by Xeno on August 1, 2013
The NSA has made hush-hush payments of at least $150 million to Britain’s GCHQ spying agency over the past three years to influence British intelligence gathering operations. The payouts were revealed in new Snowden leaks published by The Guardian.
The documents illustrate that the NSA expects the UK’s Government Communications Headquarters, known as GCHQ, to act in its interest, expecting a return on the investment, The Guardian saidThursday.
Redevelopments at GCHQ’s site at Bude in southwest England, which alone cost over $20 million, were paid for by the US National Security Agency. The facility intercepts information from transatlantic cables carrying Internet and communications information.
The revelations appear to contradict previous denials from British government ministers that GCHQ does the NSA’s “dirty work.” In addition, the latest Snowden dossier details how British surveillance operations could be a “selling point” for the US.
A document from 2010 cited by The Guardian reveals the nature of the relationship between the two organizations, stating that the US “raised a number of issues with regards to meeting NSA’s minimum expectations” attesting that GCHQ “still remains short of the full NSA ask.”
The documents declare GCHQ’s intent and the extent to which it wants to harvest phone data and Internet traffic, aiming to “exploit any phone, anywhere, any time.”
The daily also reveals the sheer volume of data Britain has increasingly gained access to. Over the past five years, the quantity of available Internet and mobile traffic has increased by 7,000 percent. However 60 percent of UK refined intelligence is still provided by the NSA.
In the course of providing the documents, Snowden repeatedly told the paper that “It’s not just a US problem” and that GCHQ is “worse than the US.”
RAF Menwith Hill base, which provides communications and intelligence support services to the United Kingdom and the U.S. is pictured near Harrogate, northern England (Reuters)
Apparently, the British spy agency blamed Russia and China for the overwhelming majority of cyberattacks against the UK and is set on developing new technologies alongside the NSA with the aim of increasing their cyberwarfare capability, according to the report.
Documents detail how the NSA provided GCHQ with $34.8 million in 2009 and $60 million in 2010, with the 2010 sum including $6 million in GCHQ support for NATO forces in Afghanistan. In 2011/12 the NSA paid a further $52.8 to GCHQ.
The leaks show that Britain fears that “US perceptions of the… partnership [could] diminish, leading to loss of access, and/or reduction in investment… to the UK.”
Snowden’s leaks informed the public in June that British spy agency GCHQ has tapped into the global network of communications, storing calls, Facebook posts and internet histories. He detailed how it shares the data with the NSA.
The documents showed that alongside managing 600m phone “events” a day, GCHQ had tapped into over 200 fiber-optic cables and had the capacity to analyze data from over 46 of them at a time. The operation, codenamed “Tempora,” had been going on for around 18 months at the time of the documents’ release.
The cables have the capacity to carry data at 10 gigabits per second, which in theory, means they could deliver up to 21petabytes of information per day. The program is continuing to develop on a daily basis.
Edward Snowden finally left Moscow’s Sheremetyevo airport on Thursday, having been granted temporary asylum in Russia after arriving –initially just in transit – in Moscow on June 23. Snowden’s departure took place some 30 minutes before his new refugee status was officially announced.