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News Article | March 2, 2017
Site: phys.org

This single finding led to a worldwide investigation that's spanned a century. While it resolved one scientific debate, it created many more. The Department of Energy's Office of Science and its predecessors have spent decades supporting scientists investigating the mystery of why superconductivity occurs under a variety of circumstances. The answer to this question holds major opportunities for scientific and technological development. About six percent of all electricity distributed in the U.S. is lost in transmission and distribution. Because superconductors don't lose current as they conduct electricity, they could enable ultra-efficient power grids and incredibly fast computer chips. Winding them into coils produces magnetic fields that could be used for highly-efficient generators and high-speed magnetic levitation trains. Unfortunately, technical challenges with both traditional and "high temperature" superconductors restrict their use. "To the extent that Tesla and Edison introducing the use of electricity revolutionized our society, ambient superconductivity would revolutionize it once again," said J.C. Séamus Davis, a physicist who works with the Center for Emergent Superconductivity, a DOE Energy Frontier Research Center. The How and Why of Superconductivity Kamerlingh Onnes' discovery set off a flurry of activity. Despite his grand visions, most of what scientists found only reinforced superconductors' limitations. One of the first big breakthroughs came nearly half a century after Kamerlingh Onnes' initial finding. While most researchers thought superconductivity and magnetism couldn't co-exist, Alexei A. Abrikosov proposed "Type II" superconductors that can tolerate magnetic fields in 1952. Abrikosov continued his research at DOE's Argonne National Laboratory (ANL) and later won the Nobel Prize in Physics for his contributions. The next big leap came in 1957, when John Bardeen, Leon Cooper, and John Robert Schrieffer proposed the first theory of why superconductivity occurs. Their theory, made possible by the support of DOE's predecessor, the Atomic Energy Commission, also won them the Nobel Prize in physics. Their theory contrasts how some metals work under normal conditions with how they act at extremely low temperatures. Normally, atoms are packed together in metals, forming regular lattices. Similar to the spokes and rods of Tinkertoys, the metals' positively charged ions are bonded together. In contrast, negatively charged free electrons (electrons not tied to an ion) move independently through the lattice. But at extremely low temperatures, the relationship between the electrons and the surrounding lattice changes. A common view is that the electrons' negative charges weakly attract positive ions. Like someone tugging the middle of a rubber band, this weak attraction slightly pulls positive ions out of place in the lattice. Even though the original electron has already passed by, the now displaced positive ions then slightly attract other electrons. At near absolute zero, attraction from the positive ions causes electrons to follow the path of the ones in front of them. Instead of travelling independently, they couple into pairs. These pairs flow easily through metal without resistance, causing superconductivity. Unfortunately, all of the superconductors that scientists had found only functioned near absolute zero, the coldest theoretically possible temperature. But in 1986, Georg Bednorz and K. Alex Müller at IBM discovered copper-based materials that become superconducting at 35 K (-396 F). Other scientists boosted these materials' superconducting temperature to close to 150 K (-190 F), enabling researchers to use fairly common liquid nitrogen to cool them. In the last decade, researchers in Japan and Germany discovered two more categories of high-temperature superconductors. Iron-based superconductors exist in similar conditions to copper-based ones, while hydrogen-based ones only exist at pressures more than a million times that of Earth's atmosphere. But interactions between the electron pairs and ions in the metal lattice that Bardeen, Cooper, and Schrieffer described couldn't explain what was happening in copper and iron-based high temperature superconductors. "We were thrown into a quandary," said Peter Johnson, a physicist at Brookhaven National Laboratory (BNL) and director of its Center for Emergent Superconductivity. "These new materials challenged all of our existing ideas on where to look for new superconductors." In addition to being scientifically intriguing, this conundrum opened up a new realm of potential applications. Unfortunately, industry can only use "high-temperature" superconductors for highly specialized applications. They are still too complex and expensive to use in everyday situations. However, figuring out what makes them different from traditional ones may be essential to developing superconductors that work at room temperature. Because they wouldn't require cooling equipment and could be easier to work with, room temperature superconductors could be cheaper and more practical than those available today. Several sets of experiments supported by the Office of Science are getting us closer to finding out what, if anything, high-temperature superconductors have in common. Evidence suggests that magnetic interactions between electrons may be essential to why high-temperature superconductivity occurs. All electrons have a spin, creating two magnetic poles. As a result, electrons can act like tiny refrigerator magnets. Under normal conditions, these poles aren't oriented in a particular way and don't interact. However, copper and iron-based superconductors are different. In these materials, the spins on adjacent iron sites have north and south poles that alternate directions – oriented north, south, north, south and so on. One project supported by the Center for Emergent Superconductivity examined how the ordering of these magnetic poles affected their interactions. Scientists theorized that because magnetic poles were already pointing in opposite directions, it would be easier than usual for electrons to pair up. To test this theory, they correlated both the strength of bonds between electrons (the strength of the electron pairs) and the direction of their magnetism. With this technique, they provided significant experimental evidence of the relationship between superconductivity and magnetic interactions. Other experiments at a number of DOE's national laboratories have further reinforced this theory. These observations met scientists' expectations of what should occur if superconductivity and magnetism are connected. Researchers at ANL observed an iron-based superconductor go through multiple phases before reaching a superconducting state. As scientists cooled the material, iron atoms went from a square structure to a rectangular one and then back to a square one. Along the way, there was a major change in the electrons' magnetic poles. While they were originally random, they assumed a specific order right before reaching superconductivity. At DOE's Ames Laboratory, researchers found that adding or removing electrons from an iron-based superconducting material changed the direction in which electricity flowed more easily. Researchers at BNL observed that superconductivity and magnetism not only co-exist, but actually fluctuate together in a regular pattern. Unfortunately, electron interactions' complex nature makes it difficult to pinpoint exactly what role they play in superconductivity. Research at BNL found that as scientists cooled an iron-based material, the electron spins' directions and their relationship with each other changed rapidly. The electrons swapped partners right before the material became superconducting. Similarly, research at ANL has showed that electrons in iron-based superconductors produce "waves" of magnetism. Because some of the magnetic waves cancel each other out, only half of the atoms demonstrate magnetism at any one time. These findings are providing new insight into why superconductors behave the way they do. Research has answered many questions about them, only to bring up new ones. While laboratories have come a long way from Kamerlingh Onnes' hand-blown equipment, scientists continue to debate many aspects of these unique materials. Explore further: Electron spin could be the key to high-temperature superconductivity


MOU with US National Lab Follows Canadian Government Grant Supporting Amy's EV Battery Recycling Work VANCOUVER, BC / ACCESSWIRE / March 2, 2017 / Larry W. Reaugh, President and Chief Executive Officer of American Manganese Inc. ("American Manganese" or "AMI" or the "Company") (TSX-V: AMY; OTC PINK: AMYZF; Frankfurt: 2AM), is pleased to announce that the Company has entered into a Memorandum of Understanding ("MOU") with Ames Laboratory, a U.S. Department of Energy National Laboratory, operated by Iowa State University. Ames is the lead national laboratory for the Critical Materials Institute, a U.S. Department of Energy Innovation hub established by Congress in 2013. The Agreement allows both parties to share an interest in collaborating in the area of materials science to synergistically augment the scope and expertise of each organization and to enhance the technological development of both organizations; Both parties recognize that the recovery and reclamation of metals and minerals from spent lithium-ion batteries represents a significant source of critical materials; and Both parties share an interest in collaborating in the exploration of electric vehicle (EV) battery materials recycling options from spent electric vehicle lithium ion batteries having cathode chemistries such as: Lithium-Cobalt, Lithium-Cobalt-Nickel-Manganese, and Lithium-Manganese. The MOU with the U.S. Government's Ames Lab follows last month's award to American Manganese from the Canadian Government's National Research Council of Canada Industrial Research Assistance Program (NRC-IRAP) for the continued development of the Company's spent electric vehicle battery cathode materials recycling technology. Ames Laboratory is a U.S. Department of Energy Office of Science national laboratory operated by Iowa State University. Ames Laboratory creates innovative materials, technologies, and energy solutions using its expertise, unique capabilities, and interdisciplinary collaborations to solve global problems. The Critical Materials Institute is a Department of Energy Innovation Hub led by the U.S. Department of Energy's Ames Laboratory. CMI seeks ways to eliminate and reduce reliance on rare-earth metals and other materials critical to the success of clean energy technologies. American Manganese Inc. is a diversified specialty and critical metal company focused on capitalizing on its patented intellectual property through low cost production or recovery of electrolytic manganese products throughout the world, and recycling of spent electric vehicle lithium ion rechargeable batteries. Interest in the Company's patented process has adjusted the focus of American Manganese Inc. toward the examination of applying its patented technology for other purposes and materials. American Manganese Inc. aims to capitalize on its patented technology and proprietary know-how to become an industry leader in the recycling of spent electric vehicle lithium ion batteries having cathode chemistries, such as: Lithium-Cobalt, Lithium-Cobalt-Nickel-Manganese, Lithium-Cobalt-Aluminum, and Lithium-Manganese (Please see the Company's January 19, 2016 press release for further details). On behalf of Management AMERICAN MANGANESE INC. Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release. This news release may contain "forward-looking statements," which are statements about the future based on current expectations or beliefs. For this purpose, statements of historical fact may be deemed to be forward-looking statements. Forward-looking statements by their nature involve risks and uncertainties, and there can be no assurance that such statements will prove to be accurate or true. Investors should not place undue reliance on forward-looking statements. The Company does not undertake any obligation to update forward-looking statements except as required by law.


The Agreement allows both parties to share an interest in collaborating in the area of materials science to synergistically augment the scope and expertise of each organization and to enhance the technological development of both organizations; Both parties recognize that the recovery and reclamation of metals and minerals from spent lithium-ion batteries represents a significant source of critical materials; and Both parties share an interest in collaborating in the exploration of electric vehicle (EV) battery materials recycling options from spent electric vehicle lithium ion batteries having cathode chemistries such as: Lithium-Cobalt, Lithium-Cobalt-Nickel-Manganese, and Lithium-Manganese. The MOU with the U.S. Government's Ames Lab follows last month's award to American Manganese from the Canadian Government's National Research Council of Canada Industrial Research Assistance Program (NRC-IRAP) for the continued development of the Company's spent electric vehicle battery cathode materials recycling technology. Ames Laboratory is a U.S. Department of Energy Office of Science national laboratory operated by Iowa State University. Ames Laboratory creates innovative materials, technologies, and energy solutions using its expertise, unique capabilities, and interdisciplinary collaborations to solve global problems. The Critical Materials Institute is a Department of Energy Innovation Hub led by the U.S. Department of Energy's Ames Laboratory. CMI seeks ways to eliminate and reduce reliance on rare-earth metals and other materials critical to the success of clean energy technologies. American Manganese Inc. is a diversified specialty and critical metal company focused on capitalizing on its patented intellectual property through low cost production or recovery of electrolytic manganese products throughout the world, and recycling of spent electric vehicle lithium ion rechargeable batteries. Interest in the Company's patented process has adjusted the focus of American Manganese Inc. toward the examination of applying its patented technology for other purposes and materials. American Manganese Inc. aims to capitalize on its patented technology and proprietary know-how to become an industry leader in the recycling of spent electric vehicle lithium ion batteries having cathode chemistries, such as: Lithium-Cobalt, Lithium-Cobalt-Nickel-Manganese, Lithium-Cobalt-Aluminum, and Lithium-Manganese (Please see the Company's January 19, 2016 press release for further details). On behalf of Management AMERICAN MANGANESE INC. Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release. This news release may contain "forward-looking statements," which are statements about the future based on current expectations or beliefs. For this purpose, statements of historical fact may be deemed to be forward-looking statements. Forward-looking statements by their nature involve risks and uncertainties, and there can be no assurance that such statements will prove to be accurate or true. Investors should not place undue reliance on forward-looking statements. The Company does not undertake any obligation to update forward-looking statements except as required by law.


Wysocki A.L.,University of Nebraska - Lincoln | Belashchenko K.D.,University of Nebraska - Lincoln | Antropov V.P.,Ames Laboratory
Nature Physics | Year: 2011

The discovery of superconductivity in LaFeAsO introduced ferropnictides as a new class of superconducting compounds with critical temperatures second only to those of the cuprates. Although the presence of iron makes the ferropnictides radically different from the cuprates, antiferromagnetism in the parent compounds suggests that superconductivity and magnetism are interrelated in both of them. However, the character of magnetic interactions and spin fluctuations in ferropnictides is not reasonably described by conventional models of magnetism. Here we show that the most puzzling features can be naturally reconciled within a rather simple effective spin model with a biquadratic interaction, which is consistent with electronic structure calculations. By going beyond the Heisenberg model, our description explains numerous experimental observations, including the peculiarities of the spin-wave spectrum, thin domain walls and crossover from a first- to second-order phase transition under doping. The model also offers insight into the occurrence of the nematic phase above the antiferromagnetic phase transition. © 2011 Macmillan Publishers Limited. All rights reserved.


Kogan V.G.,Ames Laboratory
Physical Review B - Condensed Matter and Materials Physics | Year: 2013

It is argued on the basis of the BCS theory that the zero-T penetration depth satisfies λ-2(0)â̂σTc (σ is the normal state dc conductivity) not only in the extreme dirty limit ξ0/ℓâ‰1, but in a broad range of scattering parameters down to ξ0/ℓ∼1 (ξ0 is the zero-T BCS coherence length and ℓ is the mean free path). Hence, the scaling λ-2(0)â̂σTc, suggested as a new universal property of superconductors, finds a natural explanation within the BCS theory. © 2013 American Physical Society.


King A.H.,Ames Laboratory
Scripta Materialia | Year: 2010

We assess the impact of triple lines in materials preparation and use by considering several examples of materials behavior in which they have identifiable effects. The microstructural roles of triple lines are also considered and some persistent scientific questions are raised. © 2010 Acta Materialia Inc.


Prozorov R.,Ames Laboratory | Prozorov R.,Iowa State University | Kogan V.G.,Ames Laboratory
Reports on Progress in Physics | Year: 2011

Measurements of London penetration depth, a sensitive tool to study multiband superconductivity, have provided several important insights into the behavior of Fe-based superconductors. We first briefly review the 'experimentalist-friendly' self-consistent Eilenberger two-band model that relates the measurable superfluid density and temperature dependences of the superconducting gaps. Then we focus on BaFe2As2-derived materials, for which the results are consistent with (1) two distinct superconducting gaps; (2) development of strong in-plane gap anisotropy with departure from optimal doping; (3) development of gap nodes along the c direction in a highly overdoped regime; (4) significant pair-breaking, presumably due to charge doping; (5) fully gapped intrinsic behavior (exponential at low temperatures) at optimal doping if the scattering is removed (probed in the 'self-doped' stoichiometric LiFeAs); (6) competition between the magnetically ordered state and superconductivity, which do coexist in underdoped compounds. Overall, it appears that while there are common trends in the behavior of Fe-based superconductors, the gap structure is non-universal and is quite sensitive to the doping level. It is plausible that the rich variety of possible gap structures within the general s± framework is responsible for the observed behavior. © 2011 IOP Publishing Ltd.


Grant
Agency: Department of Defense | Branch: Navy | Program: STTR | Phase: Phase II | Award Amount: 741.62K | Year: 2011

Development of an energy harvesting system utilizing the magnetostrictive material, Galfenol, will be completed in this effort. The energy harvesting system will consist of Galfenol plates or sheets, magnetic circuit components, coupling structure, power conditioning electronics, sensor, and wireless transmitter. Lab testing and relevant environment testing through sea-trials will be completed on the system and compared to the predicted performance of FEA and analytical models. In addition, Galfenol wire fabrication efforts will be advanced with the primary goal of developing a Galfenol alloy and process capable of producing wire with the appropriate texture to maximize energy harvesting properties for future 1D devices.


Ames Laboratory scientists Pat Thiel and Michael Tringides are explorers on that frontier, discovering the unique properties of two-dimensional (2-D) materials and metals grown on graphene, graphite, and other carbon coated surfaces. "Our work is somewhat of a miracle, if scientists can talk about miracles," said Tringides, who is also a professor of physics at Iowa State University. "Only a few decades ago, no one would have believed that we could see individual atoms, but our capabilities now not only allow us to see them, but manipulate them, like a child building with Lego bricks. We're able to create these materials from the bottom up, ones that could never happen in nature." They're created in a controlled laboratory setting, in an ultra-high vacuum environment, and investigated with the aid of scanning tunneling microscopy. After heating the substrate to high temperature all impurities and defects are removed. The substrate is cooled and atoms of interest are deposited one by one from specially designed sources. By tuning the temperature and deposition rate, the researchers search for the Goldilocks-like condition: atoms move not too fast and not too slow, so a truly 2-D material forms. While their research groups create a variety of surface materials in their work, the fabrications methods all have one thing in common: attempting to confine the assembly of the atoms to the 2-D plane. That's difficult, because it's counter to what atoms naturally want to do under most conditions, to assemble in three dimensions. "Atoms are chaotic by nature; we are fighting this randomness in everything we do," said Tringides. "In our work, atoms are precisely arranged on a highly reactive surface in a vacuum. Every aspect of the environment is controlled. Our work is to fabricate very small, very clean, and very perfect. Working on materials in the nanoscale demands it." Learning how these materials behave is paramount. Because 2-D materials are all surface with no bulk, a host of unique nanoscale properties—chemical, magnetic, electronic, optical, and thermal—can be attributed to them. "There's a rule book for the properties of bulk, or three-dimensional materials, and it contains big chunks that are universally understood and accepted," said Thiel, a physical chemist, materials scientist, and Distinguished Professor at Iowa State University. "But the rule book for 2-D materials is largely unwritten. There are lots of things we don't know. We get lots of surprises, and then we must explain them." Writing the rule book to the behavior of these materials is only the first step in a larger goal; creating tunable materials that could be potentially useful in a host of tech applications, including ultrafast microelectronics, catalysis, and spintronics. It's the reason that Thiel's and Tringides' research has focused upon growing metals on 2-D substrates over the last four years, turning it into a major strength of Ames Laboratory's materials research. Graphene has gained much enthusiastic attention in both scientific research and the tech industry because electrons travel very fast along its surface, explained Tringides. But to create functional devices, it necessitates patterns of nanoscale-size metal contacts on its surface, designed specifically for a desired function. "Whatever material we are trying to create, uniformity of the surface is the key to a functional device, and that is where our 'perfect' research comes in. That perfection makes us slow, but it's a trade-off," said Tringides. "If we can gain a thorough understanding of how these contacts can be produced under ideal conditions in a controlled environment, then these methods can be optimized eventually for commercial production and use." Thiel and Tringides' most recent success is the intercalation of dysprosium onto graphite layers. Intercalation is the introduction of a material into compounds with layered structures. That's a real challenge with graphite, since its purely 2-D surface results in "slick" layers with no good way to form bonds between them. "It's like a stack of blankets on a bed," said Thiel. "The blankets themselves are structurally sound, but two blankets stacked on top of each other slide around, slip off the bed, and are easily peeled off in layers." But the team has recently discovered the conditions under which they can create different types of intercalated metal-and-graphite systems, bonding those sliding blankets of material together two-dimensionally. It's a promising new way to form a thin coating of a metal protected by a carbon skin, and could lead the way to materials with unique magnetic or catalytic properties. With such a narrowly focused and highly controlled experimental focus in basic science, it could be tempting to assume that their research, like their experiments, occurs in a vacuum. But Thiel credits the success of surface science at Ames Laboratory to the close collaboration of varied research groups. "Ames Laboratory is a fertile environment for surface science experiments because we have the opportunity to collaborate directly with many scientists in diverse areas of expertise addressing the same problem from a different viewpoint," said Thiel, including specialists in photonic band gap materials, optical physics, theory, and materials fabrication. "While that collaboration model has been adopted by other institutions and is the norm now, Ames Lab's intimate size and community culture really started it all, and our achievements in surface science have benefited greatly from it." Explore further: 'Explosive' atom movement is new window into growing metal nanostructures


News Article | February 13, 2017
Site: www.cemag.us

Two-dimensional materials are a bit of a mind-bending concept. Humans live in a three-dimensional world, after all, where everything observed in our natural world has height, width, and depth. And yet when graphene — a carbon material unique in its truly flat, one-atom-deep dimension — was first produced in 2004, the mind-bending concept became reality and an unexplored frontier in materials science. Ames Laboratory scientists Pat Thiel and Michael Tringides are explorers on that frontier, discovering the unique properties of two-dimensional (2D) materials and metals grown on graphene, graphite, and other carbon coated surfaces. “Our work is somewhat of a miracle, if scientists can talk about miracles,” says Tringides, who is also a professor of physics at Iowa State University. “Only a few decades ago, no one would have believed that we could see individual atoms, but our capabilities now not only allow us to see them, but manipulate them, like a child building with Lego bricks. We’re able to create these materials from the bottom up, ones that could never happen in nature.” They’re created in a controlled laboratory setting, in an ultra-high vacuum environment, and investigated with the aid of scanning tunneling microscopy. After heating the substrate to high temperature all impurities and defects are removed. The substrate is cooled and atoms of interest are deposited one by one from specially designed sources. By tuning the temperature and deposition rate, the researchers search for the Goldilocks-like condition: atoms move not too fast and not too slow, so a truly 2D material forms. While their research groups create a variety of surface materials in their work, the fabrications methods all have one thing in common: attempting to confine the assembly of the atoms to the 2D plane. That’s difficult, because it’s counter to what atoms naturally want to do under most conditions, to assemble in three dimensions. “Atoms are chaotic by nature; we are fighting this randomness in everything we do,” says Tringides. “In our work, atoms are precisely arranged on a highly reactive surface in a vacuum. Every aspect of the environment is controlled. Our work is to fabricate very small, very clean, and very perfect. Working on materials in the nanoscale demands it.” Learning how these materials behave is paramount. Because 2D materials are all surface with no bulk, a host of unique nanoscale properties — chemical, magnetic, electronic, optical, and thermal — can be attributed to them. “There’s a rule book for the properties of bulk, or three-dimensional materials, and it contains big chunks that are universally understood and accepted,” says Thiel, a physical chemist, materials scientist, and Distinguished Professor at Iowa State University. “But the rule book for 2D materials is largely unwritten. There are lots of things we don’t know. We get lots of surprises, and then we must explain them.” Writing the rule book to the behavior of these materials is only the first step in a larger goal; creating tunable materials that could be potentially useful in a host of tech applications, including ultrafast microelectronics, catalysis, and spintronics. It’s the reason that Thiel’s and Tringides’ research has focused upon growing metals on 2D substrates over the last four years, turning it into a major strength of Ames Laboratory’s materials research. Graphene has gained much enthusiastic attention in both scientific research and the tech industry because electrons travel very fast along its surface, explains Tringides. But to create functional devices, it necessitates patterns of nanoscale-size metal contacts on its surface, designed specifically for a desired function. “Whatever material we are trying to create, uniformity of the surface is the key to a functional device, and that is where our ‘perfect’ research comes in. That perfection makes us slow, but it’s a trade-off,” says Tringides. “If we can gain a thorough understanding of how these contacts can be produced under ideal conditions in a controlled environment, then these methods can be optimized eventually for commercial production and use.” Thiel and Tringides’ most recent success is the intercalation of dysprosium onto graphite layers. Intercalation is the introduction of a material into compounds with layered structures. That’s a real challenge with graphite, since its purely 2D surface results in “slick” layers with no good way to form bonds between them. “It’s like a stack of blankets on a bed,” says Thiel. “The blankets themselves are structurally sound, but two blankets stacked on top of each other slide around, slip off the bed, and are easily peeled off in layers.” But the team has recently discovered the conditions under which they can create different types of intercalated metal-and-graphite systems, bonding those sliding blankets of material together two-dimensionally. It’s a promising new way to form a thin coating of a metal protected by a carbon skin, and could lead the way to materials with unique magnetic or catalytic properties. With such a narrowly focused and highly controlled experimental focus in basic science, it could be tempting to assume that their research, like their experiments, occurs in a vacuum. But Thiel credits the success of surface science at Ames Laboratory to the close collaboration of varied research groups. “Ames Laboratory is a fertile environment for surface science experiments because we have the opportunity to collaborate directly with many scientists in diverse areas of expertise addressing the same problem from a different viewpoint,” says Thiel, including specialists in photonic band gap materials, optical physics, theory, and materials fabrication. “While that collaboration model has been adopted by other institutions and is the norm now, Ames Lab’s intimate size and community culture really started it all, and our achievements in surface science have benefited greatly from it.”

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