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. Citation: Graphene Takes the Heat (2008, February 20) retrieved 18 August 2019 from https://phys.org/news/2008-02-graphene.html A schematic of a graphene sheet placed over a trench in a substrate. Explore further Left out to dry: A more efficient way to harvest algae biomass Researchers from the University of California – Riverside (UCR) discovered that a single layer of carbon atoms arranged in a honeycomb pattern, known as graphene, exhibits far better thermal conductivity than carbon nanotubes. Their results open a new window to graphene applications in electronics, where materials that can manage heat are vital.The group’s results are described in a paper appearing in the February 20, 2008, online edition of Nano Letters.“With the continuously decreasing size of electronic devices, materials that can conduct heat efficiently are rapidly growing in importance,” said the paper’s lead author, UCR electrical engineering professor Alexander Balandin, to PhysOrg.com. “Our work increases the range of graphene applications as the thermal management material in optoelectronics, photonics, and bioengineering.” A material’s thermal conductivity is measured in the units W/m•K, read as “watts per meter per degree Kelvin.” A watt is a unit of power equal to a joule per second and a degree Kelvin is a unit of temperature. The meter is, of course, a unit of distance, since thermal conductivity is normalized to the material’s thickness. Thermal conductivity defines how well a given material conducts heat. For example, the value of thermal conductivity of silicon, the most important electronic material, is around 145 W/m•K if measured at room temperature.Carbon nanotubes have a typical thermal conductivity range of 3000 to 3500 W/m•K. Diamond, another form of carbon, comes in between 1000 and 2200 W/m•K. The single-layer graphene studied by the UCR researchers displayed a thermal conductivity as high as 5300 W/m•K near room temperature. “Graphene is particularly promising as a thermal management material because its superior thermal conductivity is supplemented by plane geometry and good integration with silicon,” added Balandin. The interdisciplinary UCR team, which included research groups of electrical engineering professor Balandin and physics assistant professor Chun Ning Lau, measured the graphene’s thermal conductivity in an unconventional way. The usual contact-based methods for measuring thermal conduction are not appropriate for graphene because it is only a single atom thick. Instead, the group used a noncontact approach: They placed a sheet of graphene onto a substrate with a trench carved out of it, such that part of the graphene sheet was suspended over the trench. They then scattered laser light off the suspended portion and measured the graphene’s vibrational response with a technique called Raman spectroscopy (one of several light-based methods used to learn about material properties).By carefully analyzing the graphene’s Raman spectra – its unique response to the light – and the spectra’s dependence on the laser power, the group was able to extract thermal conductivity data. The entire experimental setup is tiny, with the trench just three micrometers (millionths of a meter) in width.Citation: Nano Lett. ASAP Article, 10.1021/nl0731872Copyright 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. Carbon nanotubes are being touted by many scientists and engineers as the material of the future, with the potential to revolutionize electronic technologies. But a new study shows that nanotubes may not be the only form of carbon with the promise of great things to come.
Explore further (PhysOrg.com) — By greatly amplifying one photon from an entangled photon pair, physicists have theoretically shown that human eyes can be used as detectors to observe quantum effects. Usually, detecting quantum phenomena requires sensitive photon detectors or similar technology, keeping the quantum world far removed from our everyday experience. By showing that it’s possible to perform quantum optics experiments with human eyes as detectors, the physicists can bring quantum phenomena closer to the macroscopic level and to everyday life. The group of physicists is from the University of Geneva, and includes Pavel Sekatski, Nicolas Brunner (also from the University of Bristol), Cyril Branciard, Nicolas Gisin, and Christoph Simon. In their study published in a recent issue of Physical Review Letters, the scientists theoretically show how human eyes can be used to detect a large Bell inequality violation, which proves the existence of quantum entanglement.As the physicists explain, the key to achieving human-eye detection of quantum effects is to use the process of quantum cloning by stimulated emission. Recently, using quantum cloning, researchers in Rome have experimentally created tens of thousands of clones starting from a single-photon. Then, by amplifying one photon of an entangled pair, the researchers managed to demonstrate entanglement. In order to do this, specific detectors are required, which can distinguish two orthogonal amplified states with a high success rate. Now, what Sekatski and co-workers have shown is that the human eye performs extremely well at the task of distinguishing between orthogonal amplified states. This is a consequence of the eye’s main characteristic, namely as a detection threshold. Below a certain threshold number of incoming photons, the eye remains blind (no light is seen), whereas above the threshold the efficiency (i.e. the probability of seeing) is close to one. In their calculations, the authors also considered the influence of experimental imperfections, such as photon losses, which are inevitable in a real experiment. They found that the setup is surprisingly robust. A strong Bell violation can be obtained even in case of high losses, demonstrating the presence of entanglement. This is a very astonishing feature since entanglement is generally an extremely fragile property, highly sensitive to experimental imperfections such as losses. To solve this apparent paradox, the scientists uncovered a loophole in the system. They showed that a specific multi-photon state could actually behave exactly as the entangled state. Therefore, the high Bell violation actually witnesses the entanglement of the original photon pair, i.e. before the amplification occurs, but not the entanglement between the amplified state and the single photon. Still, the authors show that the amplified state and the single photon are nevertheless entangled, but revealing this entanglement would require more sophisticated measurements. This subtle issue provides a much better understanding of the quantum nature of amplified states, which were recently the subject of a controversy among the scientific community.As the researchers finally note, using human eyes as detectors in actual quantum experiments will face significant technical challenges. However, the possibility of observing quantum effects directly with our own eyes is fascinating. Naked eye observation would bring the observer one step closer to the quantum world.“From our theoretical study, the experimental perspectives appear very promising,” Brunner told PhysOrg.com. He added that, although there will be many technical challenges, Nicolas Gisin’s research group in Geneva has already started working on experiments.More information: Pavel Sekatski, Nicolas Brunner, Cyril Branciard, Nicolas Gisin, and Christoph Simon. “Towards Quantum Experiments with Human Eyes as Detectors Based on Cloning via Stimulated Emission.” Physical Review Letters 103, 113601 (2009).Copyright 2009 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. 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. How human eyes could detect quantum entanglement: A single-photon qubit is amplified through cloning via stimulated emission in a nonlinear crystal (red box). The clones are split into two orthogonal polarization modes, with the polarization basis varied with the help of a wave plate (green box). Each mode is then detected by a naked human eye. Image credit: Pavel Sekatski, et al. Entanglement Swapping: A New Quantum Trick Citation: Physicists Explain How Human Eyes Can Detect Quantum Effects (2009, September 29) retrieved 18 August 2019 from https://phys.org/news/2009-09-physicists-human-eyes-quantum-effects.html
Algae bloom fouls Florida Keys © 2010 PhysOrg.com (PhysOrg.com) — The hot energy news for this week comes in the form of a small box called the Bloom box, whose inventor hopes that it will be in almost every US home in the next five to 10 years. K.R. Sridhar, founder of the Silicon Valley start-up called Bloom Energy, unveiled the device on “60 Minutes” to CBS reporter Leslie Stahl on Sunday evening. Although Sridhar made some impressive claims on the show, he left many of the details a secret. This Wednesday, the company will hold a “special event” in eBay’s town hall, with a countdown clock on its website suggesting it will be a momentous occasion – or at least generating hype. Explore further Sridhar explained that the fuel cells inside the Bloom boxes are made from sand turned into thin ceramic squares, each side coated with a green or black “ink.” A single cell can power about one light bulb, but a stack of 64 of the cells could be “big enough to power a Starbucks,” Sridhar said. In between each disk there’s a metal plate, but the Bloom box supposedly uses a cheap metal alloy instead of expensive platinum. One of Bloom Energy’s early critics, Michael Kanellos of Green Tech Media, noted that researchers have been working with fuel cells since the 1830s. On “60 Minutes,” he told Stahl that, if Sridhar succeeds in making the technology affordable and efficient, there will likely be others that can, too.“The problem is then G.E. and Siemens and other conglomerates probably can do the same thing,” he said. “They have fuel cell patents; they have research teams that have looked at this,” Kanellos said.”What do you think the chances are that in ten-plus years you and I will each have a Bloom box in our basements?” Stahl asked Kanellos.”Twenty percent,” he said. “But it’s going to say ‘G.E.'”Further details on the Bloom box – its efficiency; the materials it’s made of; how much carbon dioxide, water, heat, and other emissions it produces – are still secret. In a blog post Monday afternoon, Kanellos said that he had found a US patent filed by Bloom in 2006 and granted in 2009 that mentions the material “yttria stabilized zirconia” as well as electrodes made of metals in the platinum family – although this doesn’t necessarily mean anything. More information may be revealed at Wednesday’s event, which will feature John Doerr, partner in the venture capital firm Kleiner Perkins, which has provided financial assistance to the company. (Sridhar told Stahl that an estimate of $400 million raised by Bloom so far is “in the ballpark.”) Former Secretary of State Colin Powell, a member of Bloom Energy’s board, is also scheduled to be in attendance.• Join PhysOrg.com on Facebook!• Follow PhysOrg.com on Twitter! More information: CBS As Sridhar explained to Stahl, the Bloom box is a new kind of fuel cell that produces electricity by combining oxygen in the air with any fuel source, such as natural gas, bio-gas, and solar energy. Sridhar said the chemical reaction is efficient and clean, creating energy without burning or combustion. He said that two Bloom boxes – each the size of a grapefruit – could wirelessly power a US home, fully replacing the power grid; one box could power a European home, and two or three Asian homes could share a single box. Although currently a commercial unit costs $700,000-$800,000 each, Sridhar hopes to manufacture home units that cost less than $3,000 in five to 10 years. He said he got the idea after designing a device for NASA that would generate oxygen on Mars, for a mission that was later canceled. The Bloom box works in the opposite way as the Mars box: instead of generating oxygen, it uses oxygen as one of the inputs.Video: The Bloom box on “60 Minutes.”Although Sunday was the first time Bloom Energy came public with the Bloom box (there’s not even a sign on the company’s building), several devices are already being used by about 20 well-known companies. Google, FedEx, Walmart, eBay, Staples, and others have taken advantage of tax credits to purchase the Bloom boxes, and they’re seeing cost savings in their energy bills. For example, four refrigerator-sized units have been powering a Google datacenter for the past 18 months, using about half as much natural gas as would be required to generate the same amount of energy at a traditional power plant. And at eBay, five units running on bio-gas made from landfill waste that were installed nine months ago have saved the company more than $100,000 in electricity costs, said eBay CEO John Donahoe on “60 Minutes.” Donahoe added that, on a weekly basis, the Bloom boxes generate five times as much power than the 3,000 solar cells that are installed on the roofs of the company’s buildings. Citation: Will Bloom box replace power grid? Details on Wednesday (w/ Video) (2010, February 23) retrieved 18 August 2019 from https://phys.org/news/2010-02-bloom-power-grid-wednesday-video.html K.R. Sridhar holds two Bloom boxes, which together he says could power a US home. Credit: CBS. 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.
Moon. Photo courtesy of NASA Journal information: Nature Geoscience More information: The proto-Earth as a significant source of lunar material, Nature Geoscience (2012) doi:10.1038/ngeo1429AbstractA giant impact between the proto-Earth and a Mars-sized impactor named Theia is the favoured scenario for the formation of the Moon. Oxygen isotopic compositions have been found to be identical between terrestrial and lunar samples, which is inconsistent with numerical models estimating that more than 40% of the Moon-forming disk material was derived from Theia. However, it remains uncertain whether more refractory elements, such as titanium, show the same degree of isotope homogeneity as oxygen in the Earth–Moon system. Here we present 50Ti/47Ti ratios in lunar samples measured by mass spectrometry. After correcting for secondary effects associated with cosmic-ray exposure at the lunar surface using samarium and gadolinium isotope systematics, we find that the 50Ti/47Ti ratio of the Moon is identical to that of the Earth within about four parts per million, which is only 1/150 of the isotopic range documented in meteorites. The isotopic homogeneity of this highly refractory element suggests that lunar material was derived from the proto-Earth mantle, an origin that could be explained by efficient impact ejection, by an exchange of material between the Earth’s magma ocean and the protolunar disk, or by fission from a rapidly rotating post-impact Earth.Press release (PhysOrg.com) — It’s beguiled watchers since before records were kept, and today still, it fills poets with pensive musings, and scientists with enchanting questions. Where did the moon come from, and how did it get there? The prevailing view is that a planet named Theia entered out solar system and banged into our planet with sufficient force to push some of the molten material from our planet into orbit. Over time, that material coalesced to form the moon. Now, new research from geophysical scientist Junjun Zhang and colleagues, suggests that such thinking might be wrong. In their paper published in Nature Geoscience, they find that in comparing titanium isotopes from both the moon and the Earth, that the match is too close to support the theory that the moon could have been made partly of material from another planet. Earth’s makeup found to be more diverse than previously thought © 2012 PhysOrg.com Scientists had already found that oxygen isotopes from the Earth’s mantle and the moon were nearly identical, but that wasn’t enough to put a dent in the theory that a collision with Theia had created the moon because oxygen isotopes from the Earth could have mixed with isotopes from the mass of molten material circling the planet after impact. Now, though, because titanium isotopes are not nearly so easily exchanged, it’s difficult to theorize that the same sort of mixing could have occurred.Most scientists agree that if a planet had smacked into Earth and the moon came about as a result, than the moon ought to be made of some of that other planet as well. Some say the laws of physics suggest it would be somewhere in the neighborhood of forty percent. If that’s the case, why don’t studies of rocks brought back by the Apollo missions show evidence of this other planet?Some suggest the moon didn’t come about as a result of an impact at all, but from parts of the Earth being flung into orbit due to a faster spin than we now have. Unfortunately, there is no evidence thus far to support the notion that the Earth ever spun that fast. Others suggest that perhaps it wasn’t a planet that struck the Earth but an object made of ice, which would have evaporated leaving no evidence behind that it caused a huge chunk of the Earth to be knocked into orbit.And some, despite the new evidence, still cling to the belief that it could have been Theia, if Theia were made of nearly the exact same stuff as the Earth, meaning the isotopes would be the same. The odds for that are pretty slim, but not impossible. Hopefully new research will one day provide us with a definitive answer. Until that day though, it seems we will all have to just keep on musing. Explore further Citation: New research provokes more questions about the origin of the moon (2012, March 26) retrieved 18 August 2019 from https://phys.org/news/2012-03-provokes-moon.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.
After exploring different realms of music for about 25 years, Indo-rock fusion band Indian Ocean senses a refreshing wave of change with Bollywood embracing alternative music. Rahul Ram, the band’s bass guitarist and lead vocalist, points out that the world of Bollywood may seem to be calm from outside, but deep down, it is turbulent, making it a ‘demanding place’ for indie artistes.“One of the changes that I have witnessed is that indie (independent) artistes are entering Bollywood. Directors have grown up listening to indie music and they want to include such kind of music in their movies. Bollywood is opening up to alternative music,” Ram told IANS in an interview here.
Childhood stress may have a bigger influence on weight gain by women than stress during adulthood, says a study.Interestingly, the study that appeared online in the journal Social Science & Medicine found that neither childhood nor adult stress was associated with weight gain for men. “These findings add to our understanding of how childhood stress is a more important driver of
KOLKATA/Darjeeling: A ten member Chinese delegation visited Headquarter Eastern Command, Kolkata, on Thursday. The delegation was led by Lt Gen Liu Xiaowu, Deputy Commander of Western Theatre Command of PLA. Before arriving at Kolkata, the team has visited New Delhi, Agra and Sukna.The visit is a positive step towards enhancing the bilateral defence cooperation mechanism between the two countries, which would help in maintaining peace and stability along the LAC. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedThe delegation visited Headquarters, Eastern Command (HQ EC) at Fort William, where they interacted with Lt Gen Sunil Srivastava, Chief of Staff, EC and other officers. The delegation was conducted around in Fort William and later taken on a visit to Victoria Memorial, prior to their departure from Kolkata.The PLA delegation had departed for Kolkata from Sukna earlier on Thursday.They had arrived at Sukna on July 3. On arrival at the headquarters of the 33 Corps, Lt Gen Xiaowu had a meeting with Lt Gen. Pradeep M Bali, GOC, 33 Corps. This was followed by a delegation level meeting on Wednesday. Also Read – Naihati: 10 councillors return to TMC from BJPThe meetings had ended on a positive note and both the Chinese and the Indian sides had expressed satisfaction at the outcome of the interactions. “The interactions will contribute towards maintaining peace and tranquility on the borders” stated a release. A cultural show and a banquet had been held in Sukna in honour of the visiting Chinese delegation. The visit of the PLA delegation is being seen as of great importance to the armies of the two nations, with the objective of enhancing bilateral defence cooperation, increasing interactions at military commander’s level and implementation of various agreements to maintain peace and tranquility at the borders. Incidentally, the Sukna meet is being seen as the result of meetings between Indian Prime Minister Narendra Modi and Chinese President Xi Jinping at Wuhan and Qingdao in the recent past. In both the meetings, the two heads had resolved to strengthen bilateral ties between the nations.The last delegation level meeting had taken place at the Headquarters of the Eastern Command at Kolkata in February 2017.Defence Observers opine that the meetings between the two armies are of immense importance, especially after the Doklam standoff.
Kolkata: Three iron rods pierced the body of a mason after he fell from the roof of an under-construction building at Champahati area of Baruipur in the South 24-Parganas district on Wednesday morning.The victim, identified as Uday Sardar, was immediately taken to the Baruipur Super-Specialty Hospital by the local people. The doctors in the hospital did not want to take any risk as the patient still had the three iron rods that had gone through the right side of his abdomen. Also Read – Rain batters Kolkata, cripples normal lifeThe victim was then taken to Calcutta National Medical College and Hospital (CNMCH), where a digital x-ray was performed on the patient. It was not easy for the technicians to carry out the x-ray as he had to be kept in a seated posture.The doctors at CNMCH successfully removed the three rods from his body, following a critical surgery that lasted for hours. The patient, however, is still stated to be in a critical condition due to the severe nature of his injuries. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedAfter examining the reports, the doctors at the hospital found that one rod was located near his kidney, while another was close to his intestine. The third one was below his liver.The hospital authorities felt the need of an emergency surgery but there were many challenges before them.A medical board has been formed, comprising 7 doctors including the head of the department of general surgery and the heads of the Orthopedic department, Cardiothorasic department, Neuro surgery and Urology department of the hospital. The medical board was in a fix as the iron rods were nearly 3 feet long. The main concern for the doctors was removing the rods as it could make the patient bleed to death.Senior PWD engineers were asked to rush to the hospital and see if they could make the rods shorter in length by cutting them from both ends, as it would have been extremely difficult for the doctors to remove the rods otherwise.The PWD engineers, however, told the doctors that cutting the rods which had already pierced his body, might damage the organs due to the vibration which will be created.The medical board later started the operation on Wednesday evening, with the PWD engineers inside the OT. A huge quantity of blood was arranged by the hospital authorities before starting the operation.A senior official of the hospital said that the iron rods have been removed successfully.
Women have come a long way after battling against all odds but still there are women, who are yet to take their first step. Le Meridien, in association with Joining Hands (a non-profit organisation), has come up with a new initiative that will train underprivileged women from economically weaker sections in the national Capital, to become a part of hospitality sector. The women will be trained in various sections within the hospitality sector, which would enhance their chance of acquiring jobs for a better livelihood. Also Read – ‘Playing Jojo was emotionally exhausting’The training will take place for six months where 25 women will learn the intricacies of different departments under the operational section of the hospitality sector. The sole aim is to help them transform into confident women, who can face all the challenges of life.Nidhi Bhasin, trustee of Joining Hands said: “We are very excited about this initiative- the hospitality industry offers huge opportunities for employment. The sector is manpower intensive and people also good exposure to health, hygiene and general grooming. The women participating in this initiative will inspire other women in their communities and will be drivers of change towards cleaner and healthier communities.” Also Read – Leslie doing new comedy special with NetflixShe added that these women will take back home the lessons taught in this profession and it will instill confidence in them to achieve their goals. Meneka Gandhi, Union minister for Women and Child Development was present at the launch and she emphasised on the need for encouragement. She said: “The craftsmen of this country carry legacy of unique artworks that are very well known but they don’t know how to adapt to change. This is where we have to step in to help them improve their livelihood.” The course has been designed in such a manner that it will provide a hands-on experience to the women. The students will work in the hotel for experience and be later employed if they’re good at it. For others there will be a placement drive, which will give them opportunities to work in other hotels. When Millennium Post asked about the fee structure, Nidhi Bhasin said: “We’re charging a nominal fee of Rs 300 per month so that the women, who’ve joined the course, do not take this lightly.”Some of the students were present at the launch and they happily spoke about it. “I am excited about this course. Till now we have learnt the basics as the course started in January. We are being taught the basics of English language as well such as the usage of ‘has’ and ‘have,” said Samikhsha, a student of the pilot batch.Talking more about the potential that this sector has, Meena Bhatia, vice president, Marketing and Operations, Le Meridien New Delhi said: “There is a growing need to include women in the organised sector and the hospitality industry offers great opportunities for women to join the work force. In my experience, women do exceedingly well in the key areas of housekeeping, food and beverage service, food and beverage production and the front office.
Darjeeling: The unique festival of “Tiwar” commenced with “Kak Tiwar” on Monday in Darjeeling and Kalimpong.Dipawali is celebrated in a unique way in Darjeeling. The 5 days of “Tiwar” or “Yamapanchak,” is commemorated in the honour of “Yamraj” — the mythological Lord of Death. The first day of Tiwar is Kak Tiwar, dedicated to the crows, believed to be the bird associated with Yamraj. On this day food is left on rooftops and open spaces for the crows. Also Read – Rain batters Kolkata, cripples normal lifeThe next day is Kukur Tiwar. On this day marigold garlands are put on dogs with vermillion being applied on the forehead of dogs. The dog is offered a sumptuous meal. Even stray dogs are not left out on this day and people offer food to them as well. The third day of Tiwar, which falls on the day of Dipawali, is commemorated as Gai Tiwar. Early in the morning, the cows which symbolise goddess Lakshmi are worshipped. The houses are painted and marigold garlands are put on doors to welcome Goddess Lakshmi. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedIn the evening after Lakshmi Puja, tika is annointed on the forehead of seven small girls as they are worshipped as the forms of Lakshmi. Diya or lamp is lit in the main altar of the house. Along with the diyas, copper vase called Gagri is kept filled with water and decorated with flowers. Several groups of girls dressed in traditional Gunue Cholo sit outside the main entrance of houses and sing the traditional “Bhailo.” The next day of Gai Tiwar or Laxmi Puja is the Goru Tiwar — the day dedicated to the ox. In the evening “Deushi” is sung by groups of boys wearing traditional “Daura Suruwal” and playing traditional musical instruments, madal, chyabrung and jhyamta. The five-day Tiwar concludes with “Bhai-Tika.” Both Bhailo and Deushi are forms of folk culture. Both have got a common mythological background. According to mythology, during the Satya Yug, Lord Vishnu in the form of a dwarf had asked for alms from King Bali. King Bali was renowned for his charitable nature. Keeping his word, King Bali gave away his kingdom to Lord Vishnu. The girls of his kingdom fearing destruction, in groups, prayed to Goddess Lakshmi to bestow the kingdom with riches so that its lost glory could be regained. “I do not usually return home during Dussehra but try my best to get leaves for Tiwar. The festival is fun-filled and I love playing Deusi with my friends. It’s also about a sumptuous traditional spread including “Sel Roti” (traditional sweet bread) and different types of “Aachar”, stated Avisekh Bagdas who works in Delhi.