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Advance in high-pressure physics

first_imgNearly a century after it was theorized, Harvard scientists report they have succeeded in creating the rarest material on the planet, which could eventually develop into one of its most valuable.Thomas D. Cabot Professor of the Natural Sciences Isaac Silvera and postdoctoral fellow Ranga Dias have long sought the material, called atomic metallic hydrogen. In addition to helping scientists answer some fundamental questions about the nature of matter, the material is theorized to have a wide range of applications, including as a room-temperature superconductor. Their research is described in a paper published today in Science.“This is the Holy Grail of high-pressure physics,” Silvera said of the quest to find the material. “It’s the first-ever sample of metallic hydrogen on Earth, so when you’re looking at it, you’re looking at something that’s never existed before.”In their experiments, Silvera and Dias squeezed a tiny hydrogen sample at 495 gigapascal (GPa), or more than 71.7 million pounds per square inch, which is greater than the pressure at the center of the Earth. At such extreme pressures, Silvera explained, solid molecular hydrogen, which consists of molecules on the lattice sites of the solid, breaks down, and the tightly bound molecules dissociate to transforms into atomic hydrogen, which is a metal.While the work creates an important window into understanding the general properties of hydrogen, it also offers tantalizing hints at potentially revolutionary new materials.“One prediction that’s very important is metallic hydrogen is predicted to be meta-stable,” Silvera said. “That means if you take the pressure off, it will stay metallic, similar to the way diamonds form from graphite under intense heat and pressure, but remain diamonds when that pressure and heat are removed.”Understanding whether the material is stable is important, Silvera said, because predictions suggest metallic hydrogen could act as a superconductor at room temperatures.“As much as 15 percent of energy is lost to dissipation during transmission,” he said, “so if you could make wires from this material and use them in the electrical grid, it could change that story.”A room temperature superconductor, Dias said, could change our transportation system, making magnetic levitation of high-speed trains possible, as well as making electric cars more efficient and improving the performance of many electronic devices. The material could also provide major improvements in energy production and storage. Because superconductors have zero resistance, superconducting coils could be used to store excess energy, which could then be used whenever it is needed.Metallic hydrogen could also play a key role in helping humans explore the far reaches of space, as a more powerful rocket propellant.Microscopic images of the stages in the creation of atomic molecular hydrogen: Transparent molecular hydrogen (left) at about 200 GPa, which is converted into black molecular hydrogen, and finally reflective atomic metallic hydrogen at 495 GPa. Courtesy of Isaac Silvera“It takes a tremendous amount of energy to make metallic hydrogen,” Silvera explained. “And if you convert it back to molecular hydrogen, all that energy is released, so that would make it the most powerful rocket propellant known to man, and could revolutionize rocketry.”The most powerful fuels in use today are characterized by a “specific impulse” (a measure, in seconds, of how fast a propellant is fired from the back of a rocket) of 450 seconds. The specific impulse for metallic hydrogen, by comparison, is theorized to be 1,700 seconds.“That would easily allow you to explore the outer planets,” Silvera said. “We would be able to put rockets into orbit with only one stage, versus two, and could send up larger payloads, so it could be very important.”In their experiments, Silvera and Dias turned to one of the hardest materials on Earth, diamond. But rather than natural diamond, Silvera and Dias used two small pieces of carefully polished synthetic diamond and treated them to make them even tougher. Then they mounted them opposite each other in a device known as a diamond anvil cell.“Diamonds are polished with diamond powder, and that can gouge out carbon from the surface,” Silvera said. “When we looked at the diamond using atomic force microscopy, we found defects, which could cause it to weaken and break.”The solution, he said, was to use a reactive ion etching process to shave a tiny layer — just five microns thick, or about a tenth the thickness of a human hair — from the diamond’s surface. The diamond was then coated with a thin layer of alumina to prevent the hydrogen from diffusing into the crystal structure and embrittling it.After more than four decades of work on metallic hydrogen, and nearly a century after it was first theorized, it was thrilling to see the results, Silvera said.“It was really exciting,” he said. “Ranga was running the experiment, and we thought we might get there, but when he called me and said, ‘The sample is shining,’ I went running down there, and it was metallic hydrogen.”“I immediately said we have to make the measurements to confirm it, so we rearranged the lab … and that’s what we did.”SaveSaveSavelast_img read more

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Benches clear after a bunt breaks up a no-hitter in the Yard Goats-Thunder game

first_imgWith just two outs to go before finishing the no-hitter, Lipka decided to bunt on the first pitch he saw. It went down the first base line and he was safe at first.MORE: Watch ‘ChangeUp,’ a new MLB live whiparound show on DAZNHere is the bunt that broke up the @GoYardGoats no-hit bid in the 9th. What does Hartford starter Rico Garcia think of it? 👉 https://t.co/JKJTmZDBEb pic.twitter.com/24r6ZHwEj4— Minor League Baseball (@MiLB) June 5, 2019Bunting to break up a no-hitter is an unwritten rule in baseball (even though some agree it’s a stupid rule).So when it happens, feelings get hurt. And that was the case Tuesday night as the benches cleared after the single.Aftermath of a near fight at the end of the @GoYardGoats and @TrentonThunder game at Dunkin’ Donuts Park. 3-0 win for the Goats allowing only one hit as a team. #NoGoatsNoGlory #Pride #NBCCT @NBCConnecticut @GLucivero pic.twitter.com/N1QL5XUWFo— Paul Ross (@RealPaulRoss) June 5, 2019While there was clearly overall frustration by the team, Garcia wasn’t too upset by the act itself. But he certainly wanted to see his team finish the no-hitter.”It is what it is,” Garcia said, via MILB.com. “[Lipka] was doing what he had to do. And we were really passionate about getting the no-hitter. It is what it is. I can’t really speak for what he was trying to do or what he was trying to accomplish. It’s unfortunate we couldn’t get the no-hitter. Emotions were high after.”The Thunder finished with the lone hit and lost the game 3-0 as Bowden safely recorded the next two outs. The Hartford Yard Goats were carrying a no-hitter heading into the ninth inning Tuesday night against the Trenton Thunder, but then things got a little out of hand.Starting pitcher Rico Garcia did most of the damage, pitching six innings and recording 11 strikeouts. Then relievers Jordan Foley and Logan Cozart each pitched one inning without allowing a hit. Ben Bowden came in for the save, and recorded one out before facing Trenton’s Matt Lipka. UPDATE: According to NJ.com’s Mike Rosenstein, Lipka was the victim of online harassment following his decision to bunt.Via NJ.com:According to a source not authorized to speak on behalf of the Thunder organization, the 27-year-old Lipka received death threats on social media following Tuesday’s game. The Thunder are the Double-A affiliate of the New York Yankees. The source says the Yankees have been alerted to the threats and are investigating.It’s worth noting Lipka got on base while the game was still close. If just one other batter had gotten on base after him, then the tying run would have been at the plate.last_img read more

Read More Benches clear after a bunt breaks up a no-hitter in the Yard Goats-Thunder game