Professor proposes theory of unparticle physics

first_img This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Howard Georgi, a physicist at Harvard University, has recently published a paper on so-called unparticle physics, which suggests the existence of “unparticle stuff” that cannot be accounted for by the standard model. Appearing in a recent edition of Physical Review Letters, the paper says that unparticle stuff would be very different than anything seen before. “If all of the stuff that is scale-invariant couples to all the stuff that isn’t in a way that gets weaker and weaker as the energy gets lower, then it could be that, at the energies we can probe today, we just don’t see the unparticle stuff at all,” Georgi explained. “There could be a scale-invariant world separate from our own that is hidden from us at low energies because its interactions with us are so weak.”These particle interactions would appear to have missing energy and momentum distributions. Georgi has calculated the peculiar distributions of missing energy for the decay of a top quark, which would signify the production of unparticle stuff. “The very confusing question of ‘What does unparticle suff look like?’ gets replaced by a simpler question: ‘How does unparticle stuff begin to show up as the energy of our experiments is increased?’” he said.He explained that a good way of understanding unparticle stuff is with neutrinos. Neutrinos have some properties in common with unparticle stuff. For example, neutrinos are nearly massless and therefore nearly scale invariant. They couple very weakly to ordinary matter at low energies, and the effect of the coupling increases as the energy increases. “Very often, in a scattering experiment, we can infer the existence of neutrinos by adding up the energy and momentum of the colliding particles and subtracting the energy and momentum of all the particles we can see to get the energy and momentum of the ‘missing’ (which just means that we don’t see them because they escape our detectors without interacting) neutrinos,” he said. “By doing the scattering many times, we can measure a probability distribution for the missing energy and momentum. And by looking at the distribution, we can tell whether there is one or two or more neutrinos missing in the particular process we are studying. “An interesting result of my analysis is that such a distribution for a process that produces unparticles looks like the distribution for a fractional number of massless particles,” he added. “This is weird, but it follows very simply from the scale invariance of the unparticles. It is the first glimmer of an answer to the question of how unparticles begin to show up.”Because the signatures of unparticle stuff would be very distinct, LHC experiments have the potential to verify the existence of unparticle stuff immediately. Georgi says that, in his opinion, unparticle stuff would be a more striking discovery than supersymmetry or extra dimensions, both of which point to just more new particles. Unparticle stuff, on the other hand, would be a different concept altogether. “I, and a number of other researchers, am now trying to push these ideas harder,” Georgi said. “Other weird properties of unparticles have already emerged. I expect more. It is great fun. Of course, it would be even greater fun if we actually saw stuff like this at the LHC. But even if we don’t, I believe that analyses like this are useful because they can shake us out of preconceptions that could cause us to miss important physics as the energy of our machines grows.”Citation: Georgi, Howard. “Unparticle Physics.” Physical Review Letters 98, 221601 (2007).Copyright 2007 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. Explore further Georgi, a highly regarded physicist well-known for his pioneering work in areas including supersymmetry, quantum chromodynamics, and grand unified theories, explains that the low-energy physics of nontrivial scale-invariance cannot be described in terms of particles. In this initial investigation of the idea, he gives a quantitative scenario of the production of unparticle stuff, and predicts how it could be experimentally detected in the upcoming Large Hadron Collider (LHC), the most powerful particle accelerator that will open in early 2008.In scale-invariant theory—where objects don’t change when their dimensional qualities are multiplied by a rescaling parameter—the concept of particles doesn’t work because most particles have a definite nonzero mass. In quantum mechanics, this isn’t a problem because the standard model does not have scale-invariance. But Georgi suggests that there could be an undiscovered sector of the standard model that is exactly scale-invariant.“I have been having a lot of fun with this,” Georgi told PhysOrg.com. “It is a phenomenon that has been understood mathematically for a long time, in the sense that we know of theories that have the peculiar property of scale-invariance. It is hard to describe this because it is so different from what we are used to. For us it makes a big difference whether we measure masses in grams or kilograms. But in a scale-invariant world, it makes no difference at all.”Georgi explains that photons, which are particles of light, have the property of scale invariance because they have zero mass. Multiplying all the photon energies by a factor of 1000 would make them look exactly the same. “Clever theorists (like Ken Wilson) showed long ago that there were crazier possibilities which do not involve particles with zero mass, but still have the property that energies can be multiplied by any factor to give a physically equivalent theory,” Georgi said. “[But] this is impossible if there are particles with any definite nonzero mass. That is why I called this ‘unparticle’ stuff.”This scale-invariant sector would interact very weakly with the rest of the standard model, making it possible to observe evidence for unparticle stuff, if it exists. The unparticle theory is a high-energy theory that contains both standard model fields and “Banks-Zaks” fields (which has scale-invariance at an infrared point). The two fields can interact through the interactions of ordinary particles under high enough machine energy or a low enough mass scale. center_img Citation: Professor proposes theory of unparticle physics (2007, June 11) retrieved 18 August 2019 from https://phys.org/news/2007-06-professor-theory-unparticle-physics.html Unparticles may provide a new path to superconductivity Unparticles, but not particles, can fit in a theory that has the property of continuous scale-invariance, which is difficult to visualize. A fractal, like this Koch Curve, is an example of discrete scale-invariance because it looks the same if multiplied by a fixed number. Credit: Benoit Mandelbrot, Fractals.last_img read more

Startup company aims to harness the full potential of producing electricity from

first_img This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. (PhysOrg.com) — Matt Scullin co-founded Alphabet Energy just one year ago, but already the CEO has ambitions of turning the San Francisco-based start-up company into the “Intel of waste heat.” By harnessing the waste heat emitted by power plants, industrial furnaces, and cars, Alphabet Energy envisions that it could provide inexpensive electricity to the US grid by recycling waste heat on a much larger scale than currently exists. More information: Alphabet Energyvia: National Geographic Explore further Citation: Start-up company aims to harness the full potential of producing electricity from waste heat (2010, September 2) retrieved 18 August 2019 from https://phys.org/news/2010-09-start-up-company-aims-harness-full.html © 2010 PhysOrg.com Currently, more than two-thirds of the fuel used to generate power in the United States is lost as heat, according to a 2008 report from the Oak Ridge National Laboratory. The goal of cogeneration technology is to convert this waste heat into electric and thermal power. Although the idea has been around for more than a century, the US produces only about 9% of its power from cogeneration systems. In comparison, many European countries use cogeneration systems for a significantly larger portion of their electricity production, with Denmark producing more than 50% of its power using waste heat recovery systems. In the US, the Department of Energy has a goal for recycled waste heat to account for 20% of US electricity production by 2030.Alphabet Energy’s strength lies in its recent development of a thermoelectric chip that can be inserted into a wide variety of exhaust flues, engines, or other heat-producing devices to convert the waste heat into electricity. As heat essentially pushes electrons through the material, the device can be connected to the grid to feed in the electricity in real time. As the company explains, the device’s key advantage is the novel material – a relatively abundant, low-cost material that has been modified by researchers at the Lawrence Berkeley National Laboratory to lower its thermal conductivity and increase its electricity output using a smaller amount of heat. Another advantage is that the thermoelectric chip is produced using similar methods used for producing the microchips used in electronic devices, which should lower production costs.These improvements may allow Alphabet Energy to lower the cost of installing the system to less than half that of current systems, to under $1 per watt. At this cost, and depending on the properties of the heat generation system, the system could deliver a payback time of two to four years. In addition, since electricity generated from waste heat is 100% clean energy, Alphabet estimates that its technology will be able to offset more than 500 million tonnes of carbon annually.Alphabet Energy plans on performing a pilot test at an industrial facility next year, and may start commercialization in 2012. One of the challenges the company faces is that waste heat is one of the few power sources that the US government does not currently subsidize. However, recently a bipartisan group of lawmakers led by Democratic Representative Paul Tonko of New York have introduced a bill that would offer a 30% tax credit for installing waste heat recovery systems in industrial environments. Alphabet Energy estimates that the technology for waste heat recovery systems could comprise a $200 billion global market. Other US companies are also working on waste heat recovery techniques, from small start-ups to corporations including General Motors and General Electric. Besides heat from factories and power plants, future systems could also harness the heat from laptop computers and cell phones, although that technology is still in development. A greener way to power cars A coal power plant in Datteln, Germany, that transforms chemical energy into 36%-48% electricity and the remaining 52%-64% into waste heat. Image credit: Arnold Paul. Wikimedia Commons.last_img read more

Linux and Intel 386 processors will part ways

first_img “This tree removes ancient 386 CPU support and thus zaps quite a bit of complexity, which has plagued us with extra work whenever we wanted to change SMP primitives, for years,” Molnar wrote in a message to Linux kernel creator Torvalds. He spoke of the “nostalgic cost being that “your old original 386 DX33 system from early 1991 won’t be able to boot modern Linux kernels anymore.” Torvalds replied, I’m not sentimental. Good riddance.”Intel’s 32-bit 386 processor was first introduced in 1985 and production continued until 2007. In May 2006, Intel announced that 80386 production would stop at the end of September 2007. The Linux kernel was released in 1991 and was eventually ported to a number of computer hardware platforms. The general reaction among technology bloggers is that Torvalds’ decision to make the 386 processors history for Linux is not expected to bother most Linux users except for those who choose to still build on very old rigs. As for Linux moving forward, Linux 3.7 was launched on December 10. Torvalds wrote”It’s been a somewhat drawn out release despite the 3.7 merge window having otherwise appeared pretty straightforward, and none of the rc’s were all that big either. But we’re done, and this means that the merge window will close on Christmas eve.Or rather, I’ll probably close it a couple of days early. For obvious reasons. It’s the main commercial holiday of the year, after all.”Part of the news about this release is support for the ARM 64-bit architecture, with ARM support to boot into different systems using the same kernel, which translates into portability across different hardware setups. There is also support for the Intel “supervisor mode access prevention” (SMAP) security feature. The release carries new drivers and fixes too. Citation: Linux and Intel 386 processors will part ways (2012, December 14) retrieved 18 August 2019 from https://phys.org/news/2012-12-linux-intel-processors-ways.html Explore further Ubuntu 7.04 to Arrive April 19 This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. (Phys.org)—Earlier this week Linus Torvalds took away support for 386 CPUs from the Linux kernel. He agreed with the position of Red Hat engineer and Linux kernel developer Ingo Molnar to drop support for Intel’s old 386 microprocessors. For Linux users, the world is not coming to a halt. All it means is that the 386 DX33 chip will not be able to run in future versions of Linux, just in existing versions of the kernel. Intel 386-DX owners, for whatever hobbyist or other reasons, will not be able to enjoy the new Linux versions starting with 3.8. Molnár explained that the extra work involved in continuing support was greater than the returns in benefits. © 2012 Phys.orglast_img read more

Researchers discover nanoparticles can be fabricated using Leidenfrost drops w Video

first_img This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Journal information: Nature Communications French team demonstrates paramagnetic properties of liquid oxygen drops (Phys.org) —A team of researchers from several research institutions in Germany has found that certain types of nanoparticles can be created using levitated drops of heated water—Leidenfrost drops. In their paper published in the journal Nature Communications, the team describes how they created metal polymer hybrid foams and other nanoparticles using nothing more than water on a heated substrate. Play Gold nanoparticles synthesis in the Leidenfrost drop reactor: Transformation of Leidenfrost drop from yellow gold salts to plasmonic red colour of gold nanoparticles during the levitation. Credit: Nature Communications 4, Article number: 2400 doi:10.1038/ncomms3400 PausePlay% buffered00:0000:00UnmuteMuteDisable captionsEnable captionsSettingsCaptionsDisabledQuality0SpeedNormalCaptionsGo back to previous menuQualityGo back to previous menuSpeedGo back to previous menu0.5×0.75×Normal1.25×1.5×1.75×2×Exit fullscreenEnter fullscreen Play 3D synthesis and coating in the Leidenfrost drop: 3D coating of TEM grid. A rotary motion of Leidenfrost drop holds the TEM grid inside the drop during the coating. Credit: Nature Communications 4, Article number: 2400 doi:10.1038/ncomms3400 PausePlay% buffered00:0000:00UnmuteMuteDisable captionsEnable captionsSettingsCaptionsDisabledQuality0SpeedNormalCaptionsGo back to previous menuQualityGo back to previous menuSpeedGo back to previous menu0.5×0.75×Normal1.25×1.5×1.75×2×Exit fullscreenEnter fullscreencenter_img © 2013 Phys.org Plasmonic gold nanoparticles using a levitating drop reactor. Credit: Nature Communications 4, Article number: 2400 doi:10.1038/ncomms3400 Citation: Researchers discover nanoparticles can be fabricated using Leidenfrost drops (w/ Video) (2013, October 31) retrieved 18 August 2019 from https://phys.org/news/2013-10-nanoparticles-fabricated-leidenfrost-video.html Most everyone has seen Leidenfrost drops in action, they occur when dumping a small amount of water into an already heated pan—the drops that form slide around as if there is no friction due to the steam that builds up beneath them. In this new effort, the researchers noted that not only does water turn to steam in Leidenfrost drops but it appears that positive ions gather in that steam leaving negative ions to collect in the liquid above. If melted metal is added to the mix, its positive ions are attracted to the negative ions in the liquid where they react and solidify into certain types of nanoparticles.Using this technique the team found they were able to create nanoporous black gold as well as different types of nanoparticle based foams and also nanoparticle coatings that adhere to a three-dimensional substrate—all without using any toxic chemicals. Researchers have been searching for a way to create such materials in new ways that don’t result in toxic byproducts. Conventional methods rely on the use of a variety of toxic chemicals to cause the desired reactions to come about. That in turn leads to environmental problems as well as concern about the toxicity of the nanomaterials themselves. The process using Leidenfrost drops, on the other hand, is as clean as it gets, the researchers report, with no need for reducing agents—the reactions occur in the heated drops without any other mixing either—leading the researchers to describe the technique as “green chemistry.” The end result is a much cleaner way to make nanoparticles, which is good news as scientists have been discovering new uses for them in a large variety of products. The researchers believe the nanoparticles they have created thus far might one day be used in medical or electrical components. Explore further More information: Green chemistry and nanofabrication in a levitated Leidenfrost drop, Nature Communications 4, Article number: 2400 DOI: 10.1038/ncomms3400AbstractGreen nanotechnology focuses on the development of new and sustainable methods of creating nanoparticles, their localized assembly and integration into useful systems and devices in a cost-effective, simple and eco-friendly manner. Here we present our experimental findings on the use of the Leidenfrost drop as an overheated and charged green chemical reactor. Employing a droplet of aqueous solution on hot substrates, this method is capable of fabricating nanoparticles, creating nanoscale coatings on complex objects and designing porous metal in suspension and foam form, all in a levitated Leidenfrost drop. As examples of the potential applications of the Leidenfrost drop, fabrication of nanoporous black gold as a plasmonic wideband superabsorber, and synthesis of superhydrophilic and thermal resistive metal–polymer hybrid foams are demonstrated. We believe that the presented nanofabrication method may be a promising strategy towards the sustainable production of functional nanomaterials.last_img read more

Researchers create stable goldIII catalysts via oxidative addition of a carbon–carbon bond

first_img More information: Stable gold(III) catalysts by oxidative addition of a carbon–carbon bond, Nature 517, 449–454 (22 January 2015) DOI: 10.1038/nature14104AbstractLow-valent late transition-metal catalysis has become indispensable to chemical synthesis, but homogeneous high-valent transition-metal catalysis is underdeveloped, mainly owing to the reactivity of high-valent transition-metal complexes and the challenges associated with synthesizing them. Here we report a carbon–carbon bond cleavage at ambient conditions by a Au(I) complex that generates a stable Au(III) cationic complex. In contrast to the well-established soft and carbophilic Au(I) catalyst, this Au(III) complex exhibits hard, oxophilic Lewis acidity. For example, we observed catalytic activation of α,β-unsaturated aldehydes towards selective conjugate additions as well as activation of an unsaturated aldehyde-allene for a [2 + 2] cycloaddition reaction. The origin of the regioselectivity and catalytic activity was elucidated by X-ray crystallographic analysis of an isolated Au(III)-activated cinnamaldehyde intermediate. The concepts revealed suggest a strategy for accessing high-valent transition-metal catalysis from readily available precursors. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. As Kourra and Cramer note, a major challenge for chemists in the organic field is to synthesize structurally complex target molecules selectively, allowing for the development of pharmaceuticals and other valuable materials. One way to do so is via catalysis, which has proven successful in a number of ways. There still remains one area that has met with little success, however, catalysis with transition metals which exist in high oxidation states—Au(III) is one. In this new effort, the researchers have found a way to overcome the two main obstacles (poor stability and the difficulty of getting to the oxidation state via so-called “mild” techniques) researchers have faced in the past.The team’s technique consisted of inserting an existing Au(I) catalyst (biphenylene) into a carbon-carbon bond, without using any strong oxidants. The results was an Au(III) catalyst which had a biphenylene ligand. They note that the reaction occurred at room temperature, making the process relatively simple and inexpensive. Next, the group converted their catalyst into a precursor (stable) compound for storage until a reaction is needed. The researchers then put the ligand to good use—to guide oxygen atoms on substrates into groups that would bind to the metal, offering in effect, a protective shield of sorts against complementary reactions.The researchers tested their catalyst in six different types of reactions and report good product yields, which meant that their technique represents a major breakthrough in the field. They noted also that it opens the door to using Au(I) and Au(III) together, offering the benefits of both, which had not been done before. They next plan see how well their technique works with other compounds. Citation: Researchers create stable gold(III) catalysts via oxidative addition of a carbon–carbon bond (2015, January 22) retrieved 18 August 2019 from https://phys.org/news/2015-01-stable-goldiii-catalysts-oxidative-addition.html Explore further Transformations of diazo compounds catalyzed by environmentally benign iron complexescenter_img (Phys.org)—A team of researchers working at the University of California, has found a way to create stable gold(III) catalysts using oxidative addition of a carbon–carbon bond. In their paper published in the journal Nature, the team describe how they developed a technique that allowed for a carbon–carbon bond split at room temperature by an Au(I) complex that generated a stable Au(III) cationic complex. Christopher Kourra and Nicolai Cramer with École Polytechnique Fédérale de Lausanne offer a News & Views piece in the same journal issue describing the work by the team at UC. Journal information: Nature © 2015 Phys.org Routes to high-valent metal complexes. Credit: Nature 517, 449–454 (22 January 2015) doi:10.1038/nature14104last_img read more

Best of Last Week – Dark matter maybe not so dark chance

first_img Also disappointingly, a team at NASA’s WISE orbiting observatory conducted a search for advanced civilizations beyond Earth and found nothing obvious in 100,000 galaxies. There was also an update by the researchers trying to figure out what the two bright spots are on “Dwarf planet” Ceres—they report it is a giant mystery—the two spots were originally assumed to be similar, but new evidence from NASA’s Dawn space probe showed one is colder than the surrounding surface, but the other is not. They are also wondering why there are so few craters on the surface.In other news, a team of scientists developed a mesh that captures oil—but lets water through—a possible new tool for cleaning up oil spills in the future. Another team of researchers announced they had created a world-record electric motor for aircraft—it’s small, yet delivers a reported five times more power than comparable drive systems. Also a team in Senegal reported that they had observed chimps fashioning spears for hunting—the first observation of a species other than man using tools to hunt large animals. A team of researchers at the University of California also reported that brain development suffers from lack of fish oil fatty acids—in developing frogs. There was also news from the team working on The Green Brain Project—they used a bee brain simulation to pilot a drone.And finally, for those people who take statins to reduce their chances of heart attack or stroke, a new study conducted in Finland has found that the drugs also increase the risk of developing diabetes by 46%—patients will apparently have to decide for themselves whether they are worth the risk. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. © 2015 Phys.org Explore further Potential signs of ‘interacting’ dark matter suggest it is not completely dark after allcenter_img A false-color image of the mid-infrared emission from the Great Galaxy in Andromeda, as seen by Nasa’s WISE space telescope. The orange color represents emission from the heat of stars forming in the galaxy’s spiral arms. The G-HAT team used images such as these to search 100,000 nearby galaxies for unusually large amounts of this mid-infrared emission that might arise from alien civilizations. Credit: NASA/JPL-Caltech/WISE Team Citation: Best of Last Week – Dark matter maybe not so dark, chance of asteroid strike and statins increasing diabetes risk (2015, April 20) retrieved 18 August 2019 from https://phys.org/news/2015-04-week-dark-chance-asteroid-statins.html (Phys.org)—It was an interesting week for physics as a multinational team of researchers found potential signs of “interacting” dark matter that suggested the mysterious material is not completely dark after all—observations of a group of four galaxies colliding indicated one dark matter clump that appeared to be lagging behind the others, suggesting something other than gravity was at work. In other news from space, astronomers (and many others) wondered if asteroid 2012 TC4 will hit the Earth in October 2017—it came close enough back in 2012 to make a strike a possibility the next time around.last_img read more

Study shows increase in concurrent droughts and heat waves in US

first_img Explore further New index measures the magnitude of heat waves This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Long heat waves can not only cause damage to crops, they can cause cooling bills to skyrocket stressing budgets and sometimes leading to area wide economic problems. When combined with droughts, as the researchers note, they can lead to significant damage to both society and the environment. As the research pair also note, the second period of time they looked at occurred during what has been called a hiatus of rising global temperatures (which some have suggested is due to heat being sequestered in the oceans) a period when they were not able to spot any increase in frequency of droughts or heat waves—but they were able to see very clearly that the frequency of droughts coinciding with heat waves increased dramatically. They noted also that the greatest increases were associated with the longest and most severe heat waves.To come to these conclusions, the researchers studied heat and drought records over the past half century and then assigned certain definitions to conditions to allow for conducting a statistical analysis—a drought for example, was defined as a period of time during which the likelihood of precipitation was approximately 80 percent below the median precipitation level for a given area for a given time. Their analysis shows that most parts of the country experienced more concurrent droughts, but they were most prominent in the South, South West and some of the West. Notably, the reverse was found to be true for some parts of the Midwest and Northern parts of the country.The researchers conclude by suggesting their study and others like it may help officials, farmers and other people better plan for future meteorological events, perhaps helping to mitigate the damage that is caused by long concurrent heat wave and drought events. More information: Substantial increase in concurrent droughts and heatwaves in the United States www.pnas.org/cgi/doi/10.1073/pnas.1422945112AbstractA combination of climate events (e.g., low precipitation and high temperatures) may cause a significant impact on the ecosystem and society, although individual events involved may not be severe extremes themselves. Analyzing historical changes in concurrent climate extremes is critical to preparing for and mitigating the negative effects of climatic change and variability. This study focuses on the changes in concurrences of heatwaves and meteorological droughts from 1960 to 2010. Despite an apparent hiatus in rising temperature and no significant trend in droughts, we show a substantial increase in concurrent droughts and heatwaves across most parts of the United States, and a statistically significant shift in the distribution of concurrent extremes. Although commonly used trend analysis methods do not show any trend in concurrent droughts and heatwaves, a unique statistical approach discussed in this study exhibits a statistically significant change in the distribution of the data.Press release © 2015 Phys.orgcenter_img Heatwaves place substantial stress on natural and man-made environments. The impact is exacerbated when heatwaves and droughts occur simultaneously. Credit: Jennie Brewton (University of California, Irvine, CA). Citation: Study shows increase in concurrent droughts and heat waves in US (2015, September 1) retrieved 18 August 2019 from https://phys.org/news/2015-09-concurrent-droughts.html Journal information: Proceedings of the National Academy of Sciences (Phys.org)—A pair of researchers with the University of California has found that heat waves and droughts overlapping occurred more frequently during a twenty year span between 1990 and 2010 than occurred during the twenty year span 1960 to 1980. In their paper published in Proceedings of the National Academy of Sciences, Omid Mazdiyasni and Amir AghaKouchak describe their study and suggest their results indicate a statistically significant shift in concurrent extremes.last_img read more

Selfhealing catalysts make it easier to store solar energy with water

first_img(Phys.org)—Currently one of the most efficient ways to store solar energy is to transfer the energy to catalysts that split water into hydrogen and oxygen. Then the hydrogen can either be used as a fuel or later recombined with oxygen to produce water and release electricity when needed. Explore further However, one of the problems with using water to store solar energy is that the catalysts are made of earth-abundant elements (such as manganese, cobalt, and nickel) that corrode in water with a neutral pH. To address this problem, researchers have designed self-healing catalysts that can regenerate themselves in the presence of other elements, such as negatively charged phosphate or borate ions. One of the remarkable features of the self-healing catalysts is that, as long as they are operating, there is no limit to the number of times that they can heal themselves.Now in a new paper published in the Proceedings of the National Academy of Sciences, two of the researchers who have developed the self-healing catalyst, Cyrille Costentin at Paris Diderot University and Daniel G. Nocera at Harvard University, have investigated how this process works at a more detailed level.”This paper provides a quantitative model for self-healing,” Nocera told Phys.org. “It actually extends beyond energy and provides a roadmap for the design of any self-healing catalyst. The rule set is self-assembly and catalysis. If the energy input for operation of the catalyst is greater than that for self-assembly, then the catalyst should be self-healing. So the principles developed in this paper are general.”As the researchers show in their work, a catalyst can self-heal if the self-healing process requires less energy than that needed for normal catalyst operation. A simple way to control the self-healing process is to adjust the pH of the solution, since the amount of energy required for these two processes depends on the pH. The researchers show that there is a critical pH “zone of self-healing” that depends on various factors, in particular the geometry of the water-splitting cell and the phosphate or borate buffer concentration. Fortunately for practical applications, the researchers show that self-healing can occur over a wide range of pH values, including at a neutral pH for typical cell geometries and buffer concentrations, which allows for most natural water sources to be used to store solar energy. Since much of the future demand for renewable energy is expected to come from low-income, developing countries, the ability to use local natural water sources instead of pure water for storing solar energy will offer a big advantage for implementing the technology cost-effectively and on a large scale. The researchers plan to work toward this goal in the future.”The next stage is prototyping,” Nocera said. “We are using this catalyst in conjunction with CO2 and N2 fixing bacteria (papers from our group in Science in 2016 and PNAS in 2017) to make liquid fuels and fertilizer, renewably (using only air, water, and sunlight as inputs). These prototypes are currently being developed in India at this time.” , Science More information: Cyrille Costentin and Daniel G. Nocera. “Self-healing catalysis in water.” Proceedings of the National Academy of Sciences. DOI: 10.1073/pnas.1711836114 Scientists produce robust catalyst to split water into hydrogen, oxygen Citation: Self-healing catalysts make it easier to store solar energy with water (2017, September 19) retrieved 18 August 2019 from https://phys.org/news/2017-09-self-healing-catalysts-easier-solar-energy.html The self-assembly pathway used for self-healing catalysts. Credit: Costentin et al. ©2017 PNAS © 2017 Phys.org Journal information: Proceedings of the National Academy of Sciences This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

Meet Vikram Seth the artist

Art is a natural extension of novelist-poet Vikram Seth’s literature. The writer says he likes to paint­­­— both in words and colours — to create organic shapes with distinct calligraphic identities and poetic sensibilities.The author of A Suitable Boy, who went public with his mastery over the intricate art of Chinese, Arabic and Devnagari calligraphy in his anthology of poetry, The Rivered Earth last year, unveiled three word paintings for Absolut Vodka’s creative art brand in the capital.The acrylic paintings with multi-dimensional surface textures in basic earth colours of orange, green, blue, gold and black, were conceived around the impressionist motifs of Absolut Vodka bottles framed by calligraphy for a new-media text-art effect. Below each canvas were etched two lines of Seth’s poetry to capture the essence of the visuals.‘I have studied Chinese calligraphy for 15 years from my master Zhao Yizhou. When I was in China [early in his career], I used to write calligraphy with a ball pen. That is how it happened,’ Seth recalled during the unveiling of his paintings.Green is the theme of Seth’s Pyasa Pyala [The Thirsty Cup] that takes off on Harivansh Rai Bachchan’s Madhushala in Devnagari calligraphy. ‘The canvas represents the shringar rasa [love],’ the writer said.The third canvas, Na Main, Na Mai in Urdu and Nastaleeq script, painted in a palette of blue and gold, is ‘shanta [peace] rasa’.‘In Blue and Gold, I watch the evening sky/Darken, till neither remains nor I,’ Seth says of the canvas in a rush of nostalgia. It was Arab Spring when Seth was painting the canvas and his teacher, Nasser Mansour in Jordan, had to vet the writer’s calligraphy before he decided to exhibit it, the author recalled.The writer shifted home to England after buying a country home, the old Rectory in Salisbury owned by maverick 17th century metaphysical poet George Herbert, in 2003.Currently the writer is waiting for A Suitable Girl [sequel to A Suitable Boy] to emerge ‘as and when she chooses to’. read more

Welcome the faithful

first_imgSharadotsav, a three-day Maha Raas Leela festival is being organised in the Capital that opens on 6 October. The festival presents the Nritya Natika – in Kathak and Brindaban Braj Raas style on the auspicious occasion of Sharad Purnima.This venture is based on 10th chapter of Shrimad Bhagwad Gita and inspired Late Kamla Devi Chattopadhyay. The production is the culmination of extensive research and authentic imbibing of the Brindaban Braj Raas under expert gurus in the art. It’s been 37 years this dance ballet came into being. Uma Sharma, the renowned Kathak exponent has done pioneering research work on the Raas dance and drama of Brindaban. Over a decade ago she studied the technique under the guidance of Pt Ladli Sharan Sharma the octogenarian authority on the style. She has now evolved a fine blend of Kathak and Raas Leela for her annual presentation of Maha Raas at Sharad Utsav.last_img read more