Fusion scientist revives magnetic mirror machine with cool new idea

first_img This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Citation: Fusion scientist revives magnetic mirror machine with cool new idea (2006, December 13) retrieved 18 August 2019 from https://phys.org/news/2006-12-fusion-scientist-revives-magnetic-mirror.html In the cooling scheme, Fisch uses one-meter-long radio frequency waves to control nuclear fusion by cooling the alpha particle byproduct of fusion. This cooling wave resonates with specific alpha particles, cooling them and reducing their energy so that they diffuse to the periphery and quickly exit the machine. The alphas’ lost energy could possibly even heat the remaining hydrogen ions to repeat the process.Fisch’s magnetic mirror idea would allow the alpha particles to travel both perpendicular and parallel to field lines due to the open geometry of mirror machines. Torus-shaped tokamaks, on the other hand, bend the magnetic field lines back on themselves for confinement, prohibiting axial movement of particles.Fisch explains that implementing alpha particle channeling would require two conditions. Because not all particles will be affected by the radio wave (only those with identical resonances), a connection must exist between high energy particles in the center and low energy particles near the periphery so that the center particles have a path of escape. Second, too much energy gain could cause energy losses (e.g. from collisions), but since high energy particles are pulled to the magnetic axis, a particle’s distance to the axis would limit its energy gain. Fisch also predicts that, by arranging for several regions of radio waves at different frequencies, a full range of particles can be cooled and ushered to exit. He estimates that quickening this ash removal process could increase fusion reactivity in certain designs by almost three times by making more room for hydrogen fuel ions. “Right now what we have is not quite a full-fledged concept, but it is certainly an idea for a concept,” he says. “I like this cooling effect, simply because it is a ‘cool’ effect. It is just very interesting, either for tokamaks or for mirrors, or even more generally than that.” To take the next step and use these ideas in a mirror machine applicable for confining fusion, Fisch cautions that, while there is the potential to improve efficiency using these ideas, the appropriate waves need to be identified in detail. “We’re still a long way from application,” he says. “The largest challenges in controlled fusion will be to make a device that has engineering simplicity, which is where the open confinement concepts have the advantage. The open confinement concepts need to work better as confinement devices, though.”Citation: Fisch, N.J. “Alpha Channeling in Mirror Machines.” Physical Review Letters 97, 225001 (2006).By Lisa Zyga, Copyright 2006 PhysOrg.com Explore further “Now that we know that we can get to the high temperatures need for fusion, we are more concerned with the next engineering steps, like shoveling fuel in and taking the ash and heat out of the machines,” Fisch explains to PhysOrg.com. “In the long run, I would not be surprised if people eventually came back to improved open system concepts for economical fusion energy such as the mirror.”In fusion, light particles (often hydrogen nuclei) fuse into heavier ions (such as helium nuclei, or alpha particles) and release their excess mass as energy. In order to fuse, the particles must reach a very high temperature (e.g. tens of millions of degrees), transforming into the highly conductive plasma phase. Without any control of the energy being produced, though, continuous chain reactions would result in a massive explosion like the hydrogen bomb. Popular in the ‘70s but in little use today, magnetic mirror machines consist of a magnetic field with high strength at the magnetic axis in the center and low strength on the periphery. This set-up enables confinement of charged particles—and now, as Fisch finds, can allow an efficient method for cooling, which is important for controlled fusion. Fisch explains that his cooling method—called an alpha-channeling effect—is similar to an effect that he and his colleague Professor Jean Marcel Rax predicted in 1992 for use in tokamaks, which are arguably the most popular candidate for producing fusion energy today. Like magnetic mirrors, tokamaks also employ magnetic fields to confine the hot plasmas required for fusion.“In the 1980s, there was a big shoot-out between tokamaks and mirrors,” Fisch explains. “The tokamak concept won out because it simply confined heat better, and now the mirror concept is practically gone within the US. But in the 1980s people just wanted to resolve the ‘proof-of-concept’—whether or not you could bring plasma up to thermonuclear temperatures. The tokamak simply had a better shot at this because it had the better seal on heat and particles. “Now that we know that we can get to those temperatures, we are more concerned with the next engineering steps, like shoveling fuel in and taking the ash out,” Fisch continues. “But that means opening up that seal on the tokamak to accomplish these goals. The mirror machine is already ‘open’—that was its problem—so these tasks are easy. In a way, the development path for the mirror was unfortunate, since the problems it solved easily were the engineering issues which were not at the top of the then-list.”last_img read more

Why Are Pygmies Short

first_img Explore further Squid could thrive under climate change Citation: Why Are Pygmies Short? (2007, December 21) retrieved 18 August 2019 from https://phys.org/news/2007-12-pygmies-short.html A Baka pygmy dance group pictured with US Ambassador R. Niels Marquardt in Lobeke National Park, Cameroon, in 2006. Source: US Federal Government. The question is controversial. Traditional explanations attribute pygmies’ small stature to minimizing caloric requirements and walking in dense forests. However, a new study by researchers at the University of Cambridge suggests that there are some problems with this explanation, and offers an alternative hypothesis.last_img read more

New research shows ants able to discern difference between threat levels

first_img(PhysOrg.com) — In an interesting study designed to determine how well ants are able to gauge a threat, Inon Scharf and his colleagues at Johannes Gutenberg University in Mainz, Germany, have shown that even simple ants are able to clearly distinguish between serious threats and those that aren’t so dire. In their paper, published on Ethology, the team found that a species of forest ant, Temnothorax longispinosus, are able to tell on sight if an invader is a serious threat, or just a mild one, and to react more stringently when the stakes are higher. To find out just how good ants are at distinguishing between threats, Scharf and his team assembled four different types of ants in their lab. The first was another species of ant unknown to T. longispinosus, the second were ants of the same species but from another nest; the third were ants from a different but familiar species, and the fourth were so-called slave-making ants; a very serious threat due to their tendency to kill off the queen and steal the young to enslave them as workers in their own nests.Temnothorax longispinosus, a forest dwelling ant specific to the American Northeast, generally have two forms of defense; they either bite and sting intruders or try to drag them out of the nest. In the study, the researchers found that upon discovering a slavemaker ant in the nest, T. longispinosus, came at the intruder with spread mandibles and began biting and stinging for all they were worth. When discovering any of the other ants in their nest, though, they instead opted for dragging, with different degrees of effort, based on the apparent degree of threat. The competitor ants were immediately dragged out, while the efforts to do the same with the familiar but different species ants were less urgent, and the species unknown to the ants were rarely attacked at all.From the study it appears that the ants have adapted to defending their nest in ways that are the most efficient; they only go full out when the threat is so severe that the survival of the nest is at stake. Dragging an intruder out involves fewer ants and doesn’t interfere with ongoing food retrieval activities. Common house ants form supercolonies, prosper in urban settings © 2010 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. Temnothorax longispinosus. Image credit: Antweb.org More information: Differential Response of Ant Colonies to Intruders: Attack Strategies Correlate With Potential Threat, Ethology, DOI:10.1111/j.1439-0310.2011.01926.xAbstractAnimals are often threatened by predators, parasites, or competitors, and attacks against these enemies are a common response, which can help to remove the danger. The costs of defense are complex and involve the risk of injury, the loss of energy/time, and the erroneous identification of a friend as a foe. Our goal was to study the specificity of defense strategies. We analyzed the aggressive responses of ant colonies by confronting them with workers of an unfamiliar congeneric species, a non-nestmate conspecific, a co-occurring congeneric competitor species, and a social parasite—a slave-making ant. As expected, the latter species, which can inflict dramatic fitness losses to the colony, was treated with most aggression. A co-occurring competitor was also attacked, but the ants used different behaviors in their responses to both enemies. While the slavemaker was attacked by biting and stinging and was approached with spread mandibles, the competitor was dragged, a behavioral strategy only possible if the defending ant is similar in size and strength to the opponent. Non-nestmate conspecifics were treated aggressively as well, but less than the slavemaker and the co-occurring competitor, presumably because they are less easily recognized as enemies. An unfamiliar congeneric species was rarely attacked. This first detailed study comparing the aggressive responses of ant colonies toward slave-making ants to other species posing different threats indicates that the responses of ant colonies are adjusted to the risk each opponent poses to the colony.via BBC Citation: New research shows ants able to discern difference between threat levels (2011, July 5) retrieved 18 August 2019 from https://phys.org/news/2011-07-ants-discern-difference-threat.html Explore furtherlast_img read more

Researchers find correlation between face shape and procreation rates and rank in

first_img This is not the first study to look for a correlation between male face shape and aggressive behavior. In 2008, Canadian researchers Justin Carré and Cheryl McCormick compared face shape and aggression in male hockey players—they found wider-faced men on average spent more time in the penalty box.In this new effort, the researchers relied on books commemorating Finnish soldiers who served in WWII. Photographs showing the soldiers’ faces were displayed along with personal data such as information marital status, number of children, rank achieved, etc. Also listed was information about where they had served and if they had survived the war.Loehr and O’Hara scanned the faces of 795 of the soldiers (from three regiments) and then used a simple algorithm that gave a ratio of face height to width to come up with a fWHR for each one of them. Personal data given for each soldier was entered into a database along with the fWHR. Graphing software was then used to reveal trends.In analyzing the graphs the researchers found that wide-faced men tended to have more children than those men with narrow faces. They also found that narrow-faced men tended to move up in rank more often than wide-faced men did. Face shape did not, however, appear to be connected to soldier survival rates in war. The researchers theorize that this is more likely due to modern warfare techniques and practices than aggressiveness in soldiers—when a shell lands in a foxhole, they note, everyone dies. They propose that wide-faced soldiers in more distant wars might have done better than their narrow-faced peers did if they were indeed more aggressive, as the Canadian study suggests. The thinking here is that aggressiveness would be an advantage in wars where soldiers had to rely on their own skills to survive, rather than sophisticated weapons. © 2013 Phys.org. All rights reserved. Finnish troops who participated in the Winter War 1939–1940 and the distribution of (a) scaled fWHR, (b) predicted probability of surviving the Winter War (adjusted so the posterior mode at mean face width is 0.85). Figure contains all 795 individuals. (c) Total number of children for fallen soldiers and (d) probability of attaining a rank depending on fWHR. Facial width increases with values. Dark shaded area represents 50% highest posterior density region and light shaded area represents 95% highest posterior density region. Credit: Biology Letters, doi:10.1098/rsbl.2013.0049 More information: Facial morphology predicts male fitness and rank but not survival in Second World War Finnish soldiers, Published 8 May 2013 doi: 10.1098/rsbl.2013.0049AbstractWe investigated fitness, military rank and survival of facial phenotypes in large-scale warfare using 795 Finnish soldiers who fought in the Winter War (1939–1940). We measured facial width-to-height ratio—a trait known to predict aggressive behaviour in males—and assessed whether facial morphology could predict survival, lifetime reproductive success (LRS) and social status. We found no difference in survival along the phenotypic gradient, however, wider-faced individuals had greater LRS, but achieved a lower military rank. 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. Explore furthercenter_img (Phys.org) —Researchers in Finland, using photographs of soldiers marked with associated personal data have found that facial width to height ratio (fWHR) played a role in how many children they had and their rank. In their paper published in the journal Biology Letters, researchers John Loehr and Robert O’Hara describe how they measured the faces of men found in a war tribute book and compared them with personal data. Their study was part of an effort to see if they could find any correlations between wide-faced men and survival rates in war (possibly connected to aggressiveness). In so doing, they discovered some clear associations between wide faced-men and the number of children they had. They also found that narrow-faced men tended to rank higher than wide-faced men did. Citation: Researchers find correlation between face shape and procreation rates and rank in male soldiers (2013, May 9) retrieved 18 August 2019 from https://phys.org/news/2013-05-procreation-male-soldiers.html Journal information: Biology Letters Having a short wide face may indicate sporting potential, study showslast_img read more

Interpreting the malady that is Jhumpa Lahiri

first_imgIt’s always exciting when an Indian author is considered for a prestigious award abroad. Even if that author is Jhumpa Lahiri, who would have spent little more than a few holidays in the country of her parents’ birth. But my relationship with Lahiri has been a difficult one – both as a reader and a journalist. And so it was with mixed feelings that I received the news of her having been long-listed for the Booker Prize for her yet to be released novel The Lowland. Also Read – ‘Playing Jojo was emotionally exhausting’I was in college when Lahiri’s first collection of short stories, The Interpreter of Maladies, was released and won the Pulitzer award. It became something of a necessity to celebrate her work, much as a doting parent celebrates the first recitation or painting by a favourite child. My literature professor certainly believed I should like the book. And I still considered myself too young to be a sound critic of literature and confess what I really thought of it. Oh it’s not as if I didn’t think it was beautifully written. But I had a problem of principle with the subjects, or rather her representation of the Indian community, abroad and in India. It was, I felt, too stereotypical, too forced. I could tell her that you didn’t have to grow up in the US to know little of Indian history.  Also Read – Leslie doing new comedy special with NetflixEven students studying in one part of India, have little clue about the history and culture of another part. I could tell her of cousins who have grown up abroad and seemed totally rooted there, and no we didn’t make them repeat the names of their American classmates as part of any game played in candle light as one of Shoba’s relatives does in one of the stories. I could tell her that children born in the eighties and nineties in India, would as often shy away from watching their parents snap endless number of green chilies with their rice and dal meal and go for a pizza themselves, much like their counterparts in the West.  And if you studied in a good English medium school in India, you had no trouble understanding Hollywood movies… the list of things I could tell her was endless.And herein lies my second peeve point – this time as a journalist, which is the wall that she builds around herself. I have repeatedly heard a senior colleague’s account of Lahiri’s closely guarded wedding in Calcutta in 2001. The family had done its best to respect Lahiri’s wish that it be a private affair, even going to the extent of setting dogs at the paparazzi members gathered outside the venue. But the venue, menu and all details of the wedding were an open secret with some friend or family member eager enough to inform, albeit, on condition of anonymity. I had a first hand feel of it, when the author returned to Calcutta for her daughter’s first rice ceremony. This time it was an eager aunt who was ready to spill the beans, even though the author and her family remained elusive. Of this I was certain, however, that it was not shyness that held back Lahiri from interacting with the media, from being more open, as her family had claimed during her wedding. The distance she maintained was calculated and by making herself inaccessible in general, she kept alive an interest about her, that ensured more than normal coverage on those rare occasions when she did subject herself to be interviewed – during the promotion of the movie Namesake, based on her novel of the same name or before the release of her second collection of short stories Unaccustomed Earth. Perhaps it was necessary. As a later day author explained to me, ‘To write a good book is not enough, you have to sell it.’ Some might go on a publicity spree, some price their books a certain way. Lahiri, chose distance. And I can’t say it’s not a classy way of selling yourself.Meanwhile, somewhere down the years, the reader in me had lost interest in her work. I had read The Namesake and again been troubled by the recurring theme of discomfort with one’s identity, of not being able to either accept or let go of one’s roots. I didn’t read Unaccustomed Earth. And it was with mixed feelings that I picked up The Interpreter of Maladies again after learning that Lahiri is being considered for the Booker. Imagine my surprise therefore, when I could identify with the screaming silence between the estranged couple in A Temporary Matter, empathise with Miranda’s aching desires in Sexy, understand Mrs Das’s need to unburden herself to a tour guide in The Interpreter of Maladies… Perhaps over the years, I have matured enough to tune out the forced Indianness of the stories and learnt to appreciate the play of emotions and relationships. I am now looking forward to reading Unaccustomed Earthand The Lowland. My only wish, as a now sincere reader, is that she would set her characters free, relieve them of their burden of assumed identity and let them be global citizens with universal feelings.last_img read more

Scrapping of iconic Indian warship INS Vikrant begins

first_img‘We began the process of breaking INS Vikrant yesterday and it will take at least seven to eight months to complete the job,’ Abdul Zaka of ship breaking company IB Commercial (IBC), which had won the bid for the decommissioned ship for Rs 60 crore, told . Zaka said after the Supreme Court in August rejected the PIL to convert the ship into a maritime museum, IBC obtained mandatory permissions from different government authorities for dismantling it at ship breaking yard at Darukana in south Mumbai. Around 200 men have been engaged for the job. Also Read – Need to understand why law graduate’s natural choice is not legal profession: CJIBefore the Supreme Court’s verdict, the Maharashtra government had expressed its inability to maintain the vessel inducted into the Navy in 1961 and decommissioned in January 1997. In January 2014, during the hearing of a Public Interest Litigation that opposed the plan to scrap the ship, the defence ministry had told the Bombay high court that it had completed its operational life.Responding to the demand for converting it into a museum, Maharashtra government had expressed its inability to preserve it as a museum, citing financially troubles. The majestic-class aircraft carrier, purchased from Britain in 1957, played a key role in enforcing the naval blockade of East Pakistan during the Indo-Pakistan war of 1971.last_img read more

Keeping up to the Delhi spirit

first_imgWith an aim to promote cultural tourism in the city, Delhi Tourism has been hosting a series of cultural events under the banner of Dilli Haat Utsav. This festival started on September 13, 2014 and will continue till March 31, 2015. In a bid to boost international as well as local tourism in Delhi, the festival will be on for nearly 6 months. Dilli Haat Utsav offers evenings full of cultural performances every weekend at all three Dilli Haats, at INA, Janak Puri and Pitampura. The festival is being held in collaboration with Department of Art, Culture and Languages (Govt. of Delhi) and gives a promising platform to new artistes to perform in the city. Also Read – ‘Playing Jojo was emotionally exhausting’This weekend also witnessed some enthralling performances. Dilli Haat INA witnessed Usha Chabra who charmed the visitors with her mastered story-telling skills on Saturday and Dushyant Ahuja’s Sindhi Folk Musical Group from Sindhi Academy presented light music on Sunday.Dilli Haat Pitam Pura saw Santanu Chakraborty and group from Sahitya Kala Parishad showcasing Bharatnatyam dance performance on Saturday, while Natras Cultural Group from the same academy enthralled the visitors with folk dance on Sunday.Dilli Haat Janak Puri hosted National Bamboo Expo Mart (Baans Bazar) from 28-30 November. It was organised by National Bamboo Mission.last_img read more