31 Aug

Scientists Create First NonCarbon Material with NearDiamond Hardness

first_imgResearch scientists have created the first non-carbon-based material with a hardness approaching that of diamond. Their work could have a significant impact on technologies and industries that rely on diamond as a cutting and drilling tool and abrasive. Extremely hard yet metallically conductive: Researchers develop novel material with high-tech prospects Explore further Citation: Scientists Create First Non-Carbon Material with Near-Diamond Hardness (2007, March 28) retrieved 18 August 2019 from https://phys.org/news/2007-03-scientists-non-carbon-material-near-diamond-hardness.htmlcenter_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. The material is a boron nitride “nanocomposite.” This means that, rather than consisting of one large continuous crystal, it is made of crystalline boron-nitride grains that are each a few to several nanometers in size. Although research groups have previously reported boron carbonitride materials, claimed to be the second and third hardest materials after diamond, the particular versions, or “phases,” of those materials were unstable at high temperatures. In industry, this is a major drawback.“The real breakthrough would be a bulk material that is hard, tough, and thermally stable, and thus ideal for cutting and drilling. We are the first to synthesize a bulk noncarbon material that fits this description,” said Natalia Dubrovinskaia, a researcher with the University of Heidelberg and the University of Bayreuth, both in Germany, to PhysOrg.com. Dubrovinskaia is the lead author of the paper describing the new material, which appears in the March 8 edition of Applied Physics Letters.For many materials composed of crystalline grains, also referred to as polycrystalline materials, there is a grain size for which the material’s hardness is optimized. This size is often in the nanometer range.Along this line of thought, Dubrovinskaia and her colleagues synthesized and conducted several experiments on a series of polycrystalline and nanocrystalline phases of boron nitride. This characterization included measuring the samples’ “Vickers hardness,” a test that assigns a hardness value to a material based on how readily it is indented by diamond. That value can be expressed in terms of the pressure applied by the diamond – using the pressure unit “pascal” – before it makes an indentation. For very hard materials that usually means billions of pascals (gigapascals, GPa). Single-crystal diamond, the hardest type, has a hardness of about 100 GPa.The boron nitride nanocomposite synthesized by Dubrovinskaia and her group displayed a maximum hardness of 85 GPa at a grain size of about 14 nanometers, and is thermally stable up to 1600 degrees Kelvin (about 2400 degrees Fahrenheit). The material’s hardness arises from two factors: the nanoscale-grain-size effect and each grain’s two-phase composition. That is, each grain has a nanoscale crystalline structure and a sub-nanoscale structure. This complex composition significantly increases the bulk material’s mechanical strength.Prior to this research, the next hardest known material after single-crystal diamond was cubic boron nitride, a single-crystal phase of the material, which has a Vickers hardness of 50 GPa. That leaves a rather large 50 GPa gap.“This gap can be filled by boron nitride nanocomposites, particularly by tuning their grain size and the compositional structure of the grains,” says Dubrovinskaia. “These materials may come to play an important role in industry.”Citation: Natalia Dubrovinskaia, Vladimir L. Solozhenko, Nobuyoshi Miyajima, Vladimir Dmitriev, Oleksandr O. Kurakevych, and Leonid Dubrovinsky, “Superhard nanocomposite of dense polymorphs of boron nitride: Noncarbon material has reach diamond hardness.” Appl. Phys. Lett. 90, 101912 (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.last_img read more

31 Aug

Qubits and Branes Share Surprising Features

first_img Citation: Qubits and Branes Share Surprising Features (2008, July 3) retrieved 18 August 2019 from https://phys.org/news/2008-07-qubits-branes-features.html Most recently, Duff and colleagues from Imperial College London and the Institute for Research in Fundamental Sciences in Tehran, Iran, have discovered another correlation. They’ve shown that the “branes” in string theory mathematically correlate to the qubits in quantum information theory. Their study, titled “Wrapped Branes as Qubits,” is published in a recent issue of Physical Review Letters.“These relations between black holes and qubits are still mysterious,” Duff told PhysOrg.com. “The significance of this recent paper is that, by invoking branes wrapping around the extra dimensions, it resolved the puzzle of why black holes should display any kind of two-valuedness: ‘To wrap or not to wrap; that is the qubit.’”In string theory, which requires extra dimensions, branes are theoretical objects that can be used to describe parts of the universe on a quantum scale. For instance, black holes can be described by four D3-branes intersecting at an angle, which can be useful for understanding the microscopic origins of black hole entropy.In the current study, the researchers have shown that four D3-branes can also be wrapped around the six extra dimensions of space (that exist in 10-dimensional string theory) in a way that closely resembles an entangled three-qubit state. As the physicists explained, the way that each D3-brane can wrap one way or the other around dimensions resembles the two states that a qubit can have. The researchers showed that a similar correlation exists between M2-branes, which can wrap in one of three ways around dimensions, and qutrits, which have three possible states.To mathematically demonstrate this connection, the physicists used a well-known fact from quantum information theory: a three-qubit state can be described by five parameters (four real numbers and an angle). They showed how these five parameters correspond to the four D3 branes and the branes’ angle of intersection. The work adds to a growing body of papers published in the past year on correlations between entanglement and black holes (or quantum gravity). As the physicists described, these papers are building a kind of dictionary of translations between phenomena in one language to the phenomena in the other. “When two very different areas of physics share the same mathematics, one can learn new things about each field by borrowing techniques from the other,” Duff said. “This has been a two-way pay-off and we are certain that yet more correlations will be discovered.” However, no one yet knows whether there are any physical reasons underlying these mathematical coincidences. As Duff said, “an underlying physical basis, if it exists, would be an extra bonus.”Still, understanding the mathematical correlations could be enough to lead to some interesting applications in quantum information theory.“The weird kind of numbers known as octonions have fascinated both mathematicians and physicists for decades,” Duff said. “But in their recent books, both Roger Penrose and Ray Streater have written them off as ‘lost causes in physics’ because they have so far failed to find any application. However, we believe that the tripartite entanglement of seven qubits (inspired by stringy black holes) provides a way of testing octonions in the laboratory, and this might find applications in QI, for example, in cryptography.”More information: Borsten, L.; Dahanayake, D.; Duff, M. J.; Ebrahim, H.; and Rubens, W. “Wrapped Branes as Qubits.” Physical Review Letters 100, 251602 (2008).Copyright 2008 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. What do black holes and entangled particles have in common? Until about a year ago, physicists thought that the two entities existed in completely separate worlds. Then, in 2007, physicist Michael Duff from Imperial College London demonstrated a correlation between the entanglement of three qubits and the entropy of a black hole. In the past year, several studies have demonstrated even more connections. 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. (Left) A simulated view of a black hole, and (right) a qubit representation. Credit for black hole: Ute Kraus, physics education group, Theoretische Astrophysik Tübingen, Space Time Travel (http://www.spacetimetravel.org/).last_img read more

31 Aug

New holographic radar system can track high speed shells

first_img One of the costs associated with training military personnel is in the constant replacement of targets. To get around this problem, the DoD sent out a request for development of a system that would allow for shooting at “off-sets” – positions that are close enough to the target to measure hits versus misses, without damaging the actual target. To achieve good results in such a system, a trainee would need to see not just where the shells he’s firing are landing, but the trajectory they take in getting there. Such information helps in plotting where to send the next rounds so as to move ever closer to the intended target, improving accuracy in the process.To address the problem, engineers from Cambridge Consultants designed an entirely new kind of radar; one that uses 3D technology to create a realistic holographic image in real time that shows the trajectory of rounds fired as well as where they burst in the air or when they hit a target; all of this in a 360° image. More information: www.cambridgeconsultants.com/news_pr304.html Citation: New holographic radar system can track high speed shells (2011, September 23) retrieved 18 August 2019 from https://phys.org/news/2011-09-holographic-radar-track-high-shells.html 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) — The British firm Cambridge Consultants has announced the successful test of its new 3D holographic radar system that can track fired shells traveling up to 1000 miles per hour. The new system called the Land and Surface Target Scorer (LSTS) and developed for the U.S. Department of Defense (DoD), is expected to help lower the cost of training and hopefully defend against small high speed enemies. GPS-Based Fuze Expected To Triple Cannon’s Accuracy The biggest hurdle the team faced was in differentiating the shell it was tracking from surrounding “noise.” In real world environments, everything from moving water to other projectiles to debris fragments can produce radar hits making it difficult to discern what is what. The new system had to have a way of clearing all the other stuff away to allow the person manning the gun to see very clearly where his round was going. And that’s just what the recent demo of the system showed, an ability to track 5 inch shells being fired at a rate of one every three seconds.In addition to saving money on targets, such a system should also lower the cost of ammunition as it appears such a system would reduce training time. The DoD is also hoping to employ the new technology to help in tracking small fast moving targets, such as terrorists in a rubber dingy out to blow up portions of a ship as was done with the USS Cole in 2000. Explore further © 2011 PhysOrg.comlast_img read more

31 Aug

Astronomers discover superEarth planet orbiting nearby star

first_img Explore further Phase folded curve of the planetary signal detected in GJ 625 using the parameters of the MCMC model. Left panel shows the CCF measurements, right panel the TERRA measurements. Grey dots show the measurements after subtracting the detected activity induced signals. Red dots are the same points binned in phase with a bin size of 0.1. The error bar of a given bin is estimated using the weighted standard deviation of binned measurements divided by the square root of the number of measurements included in this bin. Blue line shows the best fit to the data using a Keplerian model. Credit: Mascareño et al., 2017. Scientists discover a nearby superearth 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. “Super-Earths” are planets more massive than Earth but not exceeding the mass of Neptune. Although the term “super-Earth” refers only to the mass of the planet, it is also used by astronomers to describe planets bigger than Earth but smaller than the so-called “mini-Neptunes” (with a radius between two to four Earth-radii).Located only 21 light years away, GJ 625 is an M-dwarf star (spectral type M2) about 1/3 the size and mass of the sun. Such stars offer great potential in the search for alien Earth-like worlds, as low-mass rocky planets appear to be more frequent around M-dwarfs. However, finding an Earth-like planet orbiting low-mass stars is difficult due to their stellar activity. This is because signals induced by the rotation of a star can easily mimic those of planetary origin. Therefore, the signals coming from M-dwarfs tend to be comparable to those of rocky planets close to the habitable zone of their stars.Recently, a team of astronomers led by Alejandro Suarez Mascareño of the Canary Islands Institute of Astrophysics, has completed challenging studies of GJ 625, which began in 2013 and lasted over three and a half years. The observations were conducted with the High Accuracy Radial velocity Planet Searcher for the Northern hemisphere (HARPS-N) spectrograph installed at the Telescopio Nazionale Galileo at the Roque de los Muchachos Observatory on the island of La Palma, Canary Islands, Spain.The researchers analyzed 151 radial-velocity time series from HARPS-N as part of the HArps-n red Dwarf Exoplanet Survey (HADES) radial velocity program, which resulted in the discovery of a new planet.”We report the discovery of a super-Earth orbiting at the inner edge of the habitable zone of the star GJ 625 based on the analysis of the radial-velocity (RV) time series from the HARPS-N spectrograph, consisting in 151 HARPS-N measurements taken over 3.5 yr,” the paper reads.The newly found alien world, designated GJ 625 b, has a minimum mass of 2.8 Earth masses, which makes it the lightest exoplanet found around an M2 star to date. The planet orbits its host every 14.6 days at a distance of approximately 0.08 AU from the star, which is relatively close. By comparison, Mercury orbits the sun at a mean distance of 0.38 AU. The results of radial velocity measurements allowed the team to conclude that GJ 625 b is a small “super-Earth” on the inner edge of the habitable zone and has a mean surface temperature of 350 K that is very dependent on the atmospheric parameters. Moreover, the researchers assume that the newly detected exoworld might potentially host liquid water, but more observations focused on GJ 625 b’s atmosphere are required to confirm this assumption. (Phys.org)—European astronomers report the detection of a new extrasolar world several times more massive than Earth. The newly found exoplanet, classified as a so-called “super-Earth,” is circling a nearby star designated GJ 625. The researchers detailed their finding in a paper published May 18 on arXiv.org. Citation: Astronomers discover ‘super-Earth’ planet orbiting nearby star (2017, May 29) retrieved 18 August 2019 from https://phys.org/news/2017-05-astronomers-super-earth-planet-orbiting-nearby.html More information: HADES RV Programme with HARPS-N at TNG: V. A super-Earth on the inner edge of the habitable zone of the nearby M-dwarf GJ 625, arXiv:1705.06537 [astro-ph.EP] arxiv.org/abs/1705.06537AbstractWe report the discovery of a super-Earth orbiting at the inner edge of the habitable zone of the star GJ 625 based on the analysis of the radial-velocity (RV) time series from the HARPS-N spectrograph, consisting in 151 HARPS-N measurements taken over 3.5 yr. GJ 625 b is a planet with a minimum mass M sin i of 2.82 ± 0.51 M⊕ with an orbital period of 14.628 ± 0.013 days at a distance of 0.078 AU of its parent star. The host star is the quiet M2 V star GJ 625, located at 6.5 pc from the Sun. We find the presence of a second radial velocity signal in the range 74-85 days that we relate to stellar rotation after analysing the time series of Ca II H&K and Hα spectroscopic indicators, the variations of the FWHM of the CCF and and the APT2 photometric light curves. We find no evidence linking the short period radial velocity signal to any activity proxy. © 2017 Phys.orglast_img read more

31 Aug

The Surprising Boost You Get From Strangers

first_img“People feel more connected when they talk to strangers, like they are part of something bigger,” says Gillian Sandstrom, a psychologist and senior lecturer in the Department of Psychology at the University of Essex, in Colchester, England, who studies interactions between strangers. In research studies, Dr. Sandstrom has shown that people’s moods improve after they have a conversation with a Starbucks barista or a volunteer at the Tate Modern art museum in London. She’s also found that people are happier on days when they have more interactions with acquaintances they don’t know well and that students enjoy class more when they interact with their classmates. Sometimes a stranger—not a friend or a loved one—can significantly improve our day. A pleasant encounter with someone we don’t know, even a nonverbal one, can soothe us when no one else is around. It may get us out of our own head—a proven mood booster—and help broaden our perspective. They’re typically wrong. Dr. Sandstrom’s research shows people underestimate how much another person will like them when they talk for the first time. And in a study in which she asked participants to talk to at least one stranger a day for five days, 99% said they found at least one of the conversations pleasantly surprising, 82% said they learned something from one of the strangers, 43% exchanged contact information, and 40% had communicated with one of the strangers again, an indication they might be making friends. Read the whole story: The Wall Street Journal Sue took my hand in both of hers, patted it, and held on tight. We were five minutes into the worst turbulence I’d ever experienced—approaching Boston’s Logan International Airport in a severe winter storm—when I turned to the woman next to me and said: “Hey, would you mind chatting with me for a few minutes? I’m really nervous.” We hadn’t spoken much during the flight, other than the usual pleasantries. But my seatmate seemed friendly. And I suddenly felt desperate for a human connection. “Sure, my name is Sue,” the woman replied, smiling warmly. “What brings you to Boston?” I started to explain that I was on a business trip. Then the plane lurched violently, and I blurted out: “I might need to hold your hand, too.” And yet most people resist talking to strangers, she says. They fret about the mechanics of the conversation—how to start, maintain or stop it. They think they will blather on and disclose too much—or not talk enough. They worry they will bore the other person.last_img read more

31 Aug

A fashion form reinvented

first_imgHere’s to things of the past that deserve to be brought back with all there culture, heritage and splendor. Designer Niki Mahajan is presently working to revive the almost extinct craft of Lucknow – Badla. Badla is an old Lucknow embroidery where the metal is first stretched for long to get very thin, paper kind density. The strip of metal is then passed through flames to get different colours and then cut into very fine wires. These metal wires are then inserted in the fabric and beaten with a tinny hammers for hours and then embroidered. Considering the amount of time that goes into it, there are just a handful of Badla craftsmen left. To revive the glory of this beautiful metal embroidery, Mahajan has set up a unit in Lucknow where she has employed people associated with this craft and has been successful in revival of this art.last_img read more

31 Aug

France gets a framed taste of religious India

first_imgPoignant photos capturing the essence of Udaipur, its beautiful heritage buildings, natural beauty and particularly the expressions of religion by people of different faiths, are currently on display in Strasbourg, France.Clicked by French photographer Albert Huber, the photos are part of a month-long exhibition of pictures that showcases the sacred in the cities of Udaipur and Strasbourg.Titled ‘Seeking the Sacred’, the exhibition is the outcome of an exchange pact inked between the two cities. Also Read – ‘Playing Jojo was emotionally exhausting’‘In the historical Udaipur, I am the happy photographer. I photographed the narrow streets and living and the baroque palaces in their bountiful natural beauty,’ says Huber.The photographer who was in Udaipur in April this year says, ‘I photographed the extraordinary royal palace, the  women in a temple, the Protestants celebrating Good Friday in church and Muslims offering prayers at a mosque.’ Juxtaposing Huber’s pictures are those by Anuradha Sarup who photographed the sacred rituals of people in Strasbourg. Also Read – Leslie doing new comedy special with Netflix‘The city is one of France’s most vibrant and culturally rich cities. I captured on film the Pre-Easter ceremonies. I also shot the mosque there, which is the second largest mosque in France,’ says Sarup.The lenswoman who spent 10 days in the French city says it was a challenge for her to capture the ‘sacred’ through the historical cultural and religious identities of its people.‘Like Udaipur Strasbourg, an ancient European settlement has a living heritage. The city and its people have adapted beautifully to changing times,’ says Sarup. The photo exhibition is an activity under the Joint Co-operation Programme (JCP) signed between Indian Heritage Cities Network Foundation, UNESCO, the Udaipur Municipal Council, the city of Strasbourg and Maharana of Mewar Charitable Foundation (MMCF), Udaipur for three years from 2011.The pact aims to strengthen Udaipur’s knowledge base, develop a framework and undertake activities to preserve its heritage and develop international collaboration and partnerships for heritage-based projects in the Rajasthan city.‘The exhibition will open new avenues of understanding between people and provide access to various artists of different faiths. It will inspire creativity and stimulate international research digital knowledge exchange,’ says Mayank Gupta, Deputy Secretary, MMCF.The photo exhibition is part of a festival, which celebrated sacred music from over the world. The three-day ‘Sacred Days of Strasbourg’ inaugurated on May 23 with Hindu and Buddhist chants saw performances from 10 countries.After the exhibition closes on June 18 in Strasbourg it is scheduled to travel to Udaipur later this year and be showcased at the City Palace Museum there.Meanwhile, French photographer Huber says, ‘There is a lot I received in Udaipur and a lot more calls me back.’last_img read more

31 Aug

Missing Delhi resident found murdered in Sonipat

first_imgA 23-year-old youth and resident of New Delhi, who had gone missing since April 15 was found murdered in the agricultural fields of Dhundpur village of Rai sub-division, Sonipat on Saturday evening.The victim was identified as Chintan Saini, a resident of Rohini. His highly decomposed body was recovered from the wheat fields of the village. Inspector Savit Kumar, SHO of the Rai police station said that farm labourers spotted the dead body at around 5.30pm. “The body had injury marks on the face. This could have been done to mislead the police about the identity of the deceased. On searching through his clothes, we found his driving license issued from New Delhi. On enquiries, it was revealed that the victim had gone missing from New Delhi and an abduction case has also been registered,” the SHO said.After initiating preliminary investigation, the body has been sent to the civil hospital for autopsy.The victim was jobless and had got married five months ago, the SHO added.Post the filing of report, a police party from Rohini police station of New Delhi headed by an inspector had reached Sonipat. The kins of the deceased too had reached Sonipat to initiate the inquest proceedings.last_img read more

31 Aug

Believe it We are wired to be lazy

first_imgWhile you burn calories at the gym or while running in the neighbourhood park, our brain constantly works the opposite, looking for shortest route or choose to sit rather than stand, researchers report.A team from Simon Fraser University in Canada found that our nervous systems are remarkably adept in changing the way we move so as to expend the least amount of energy possible. In other words, humans are wired for laziness. Also Read – ‘Playing Jojo was emotionally exhausting’“We found that people readily change the way they walk — including characteristics of their gait that have been established with millions of steps over the course of their lifetime — to save quite small amounts of energy,” explained lead researcher Max Donelan. This is completely consistent with the sense that most of us have that we prefer to do things in the least effortful way, like when we choose the shortest walking path or choose to sit rather than stand. Also Read – Leslie doing new comedy special with Netflix“Even within a well-rehearsed movement like walking, the nervous system subconsciously monitors energy use and continuously re-optimises movement patterns in a constant quest to move as cheaply as possible,” Bonelan informed.To reach this conclusion, the researchers asked people to walk while they wore a robotic exoskeleton. This contraption allowed the researchers to discourage people from walking in their usual way by making it more costly to walk normally than to walk some other way. More specifically, the researchers made it more difficult for participants to swing their legs by putting resistance on the knee during normal walking, whereas the researchers eased this resistance for other ways of walking. This allowed the researchers to test whether people can sense and optimise the cost associated with their movements in real time.The experiment revealed that people adapt their step frequency to converge on a new energetic optimum very quickly — within minutes.What’s more, people do this even when the energy savings is quite small: less than 5 per cent. There is a bright side to this.“Sensing and optimising energy use that quickly and accurately is an impressive feat on the part of the nervous system. You have to be smart to be that lazy!” noted lead author Jessica Selinger.The findings, which were made by studying the energetic costs of walking, apply to most of our movements.The paper appeared in the Cell Press journal Current Biology.last_img read more

31 Aug

Flossing may do more harm than good

first_imgFlossing is supposedly done to get rid of pieces of food and plaque from between your teeth, which if left to fester, can cause inflammation and disease. But flossing requires a high level of dexterity and if wrongly done, will do more harm than good, according to Robin Seymour, emeritus professor of dental sciences at Newcastle University, the Daily Mail reported.Instead of removing plaque, most people end up pushing the plaque between their teeth down underneath the gums and leaving it there. Another common error is using a sawing action to drag the floss back and forth.  Also Read – ‘Playing Jojo was emotionally exhausting’This does not remove plaque effectively but it can traumatise the gums. Antiseptic mouthwashes have been shown to be particularly beneficial. Look for a mouthwash which contains cetylpyridinium chloride or CPC. It binds to proteins in the mouth and creates a protective lining which can continue working for up to 12 hours.There are around 500 different types of bacteria in the mouth and some are more sensitive to certain antibacterial agents, so a mouthwash which contains both CPC and essential oils, like the Dentyl Active range, is ideal.last_img read more