New spintronics effect could lead to magnetic batteries

first_img(A) Heating one side of a conductive rod causes heated electrons to move to the other end, creating a voltage. (B) Heating one side of a magnetized nickel-iron rod creates a “spin voltage,” with spin-up and spin-down electrons on opposite ends. Image credit: (c)2008 Nature. Citation: New spintronics effect could lead to magnetic batteries (2008, October 10) retrieved 18 August 2019 from https://phys.org/news/2008-10-spintronics-effect-magnetic-batteries.html Physicist Eiji Saitoh of Keio University in Yokohama, Japan, and colleagues from other Japanese institutions have published their results in a recent issue of Nature. As they explain, the term “spin Seebeck effect” comes from the original Seebeck effect, a thermoelectric phenomenon discovered by Thomas Johann Seebeck in the 1800s. In the Seebeck effect, heating one side of a conducting rod causes electrons at that end to heat up and move toward the cooler side, creating a voltage.The spin Seebeck effect is similar, but affects electron spin, which is the quantum physics equivalent of north-south magnetic alignment. When heating a magnetized metal, such as the nickel-iron rod, the researchers found that electrons with up spins (aligned with the rod´s magnetic field) congregated on the warmer side, while electrons with down spins (unaligned) preferred the cooler side. Essentially, this spin-segregated rod now has two electrodes and serves as the basis for a new kind of battery that produces “spin voltage,” or magnetic currents, which have been difficult to produce. With this tool, physicists can work toward developing more kinds of spintronics devices that store information magnetically.Magnetic information storage is inherently more efficient than storing information electronically because there is no waste heat. Unlike electrons that constantly bump into each other, flipping electron spins doesn´t generate heat. Reducing waste heat could lead to computer chip miniaturization, and would also mean lower power consumption and faster operational speeds. “The spin Seebeck effect allows us to pass a pure spin current, a flow of electron spins without electric currents, over a long distance,” the authors wrote in their study. “These innovative capabilities will invigorate spintronics research.”More information: Nature studyvia: Science News 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. Light may increase magnetic memory speeds 1000 times, decrease electricity consumption Explore further (PhysOrg.com) — Physicists have recently discovered that heating one side of a magnetized nickel-iron rod causes electrons to rearrange themselves according to their spins. This so-called “spin Seebeck effect” could lead to batteries that generate magnetic currents, rather than electric currents. A source of magnetic currents could be especially useful for the development of spintronics devices, which use magnetic currents in order to reduce overheating in computer chips, since, unlike electric currents, magnetic currents don´t generate heat. last_img read more

Physicists investigate fate of fivedimensional black strings

first_imgThis clip from the video below shows a five-dimensional black string evolving into a thinner string with a cascade of black holes. Eventually, the system will end in a naked singularity and finally become a five-dimensional black hole. Image credit: Frans Pretorius. Einstein equations indicate possibility of black hole formation at the LHC PausePlay% buffered00:0000:00UnmuteMuteDisable captionsEnable captionsSettingsCaptionsDisabledQuality0SpeedNormalCaptionsGo back to previous menuQualityGo back to previous menuSpeedGo back to previous menu0.5×0.75×Normal1.25×1.5×1.75×2×Exit fullscreenEnter fullscreen 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. Copyright 2010 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. More information: Luis Lehner and Frans Pretorius. “Black Strings, Low Viscosity Fluids, and Violation of Cosmic Censorship.” Physical Review Letters 105, 101102 (2010). DOI: 10.1103/PhysRevLett.105.101102 Citation: Physicists investigate fate of five-dimensional black strings (2010, September 10) retrieved 18 August 2019 from https://phys.org/news/2010-09-physicists-fate-five-dimensional-black.htmlcenter_img Explore further The physicists, Luis Lehner from the Perimeter Institute for Theoretical Physics, the University of Guelph (both in Ontario, Canada), and the Canadian Institute for Advanced Research, along with Frans Pretorius from Princeton University, have published their study in a recent issue of Physical Review Letters.The final fate of higher-dimensional black strings has been questioned many times since the early 1990s, when Gregory and Laflamme first realized that these objects are unstable (subject to what is now called the Gregory-Laflamme instability). At that time, Gregory and Laflamme conjectured that unstable black strings might eventually be “pinched off” at periodic intervals, resulting in a sequence of black holes. This idea fits with entropic considerations, since a sequence of black holes has higher entropy than a black string. However, some scientists later proved that black strings could not pinch off in a finite time as measured along the event horizon. This finding cast doubt on the possibility of a pinch-off that could be observed, and many scientists began investigating other possibilities. One of the later conjectures, which was based on a numerical simulation, found that an unstable black string can evolve into a “necklace” of spherical black holes connected by black string segments. Although this evolution involves pinch-offs, it avoids the conclusions of the no-pinch-off proof due to a technical caveat. However, the code that was used for this investigation crashed before scientists could infer a final state.In their new study, Lehner and Pretorius developed a new code that could extend this investigation without crashing. The simulation again showed the black string evolving into black holes connected by thin string segments. Since the string segments are themselves unstable, smaller black holes begin forming on these segments, and the pattern repeats on ever-smaller scales. As the self-similar cascade continues, smaller and smaller black holes form on the string segments and the string segments get thinner, until they are both arbitrarily small. Play This animation shows a black string evolving into black holes connected by thin string segments. Smaller black holes form on the unstable string segments, resulting in a cascade that leads to a naked singularity before ending as a black hole. Credit: Frans Pretorius. If quantum gravity resolves this singularity, several black holes should emerge. Then, small perturbations in the extra dimension would cause these black holes to merge into one black hole, which would be the final state of the black string.The result is especially interesting because it could violate the cosmic censorship hypothesis. Formulated in 1969 by Roger Penrose, the cosmic censorship hypothesis says that there are no naked singularities other than the Big Bang singularity; all other singularities must be isolated from the rest of the universe by some kind of horizon. The purpose of cosmic censorship is to preserve the universe’s causality, since a naked singularity would make causality break down and make it impossible to predict the behavior of future space-time based on the behavior of past space-time.“I would say the thing of most import about our work is it establishes that, at least in five dimensions, there are ‘reasonable’ solutions to Einstein’s field equations, i.e., solutions that don’t have naked singularities and aren’t special in any way, yet they naturally evolve to a nakedly-singular state,” Pretorius told PhysOrg.com. “Whether higher dimensions are key here (or whether they even exist!) is an open question, but at least this shows that the Einstein equations themselves don’t possess some ‘magical’ property that generically would enforce cosmic censorship.” Lehner added that, although the current study deals with five dimensions, the results are likely the same up to 13 dimensions. The study suggests that perhaps four dimensions is somehow “special” in that that is where cosmic censorship seems to hold its ground. To violate cosmic censorship in four dimensions, an unusual mechanism or unnatural energy source is required. In contrast, in five to 13 dimensions, naked singularities appear naturally with no fine-tuning. This finding may also help physicists find a theory of quantum gravity.“Some people expect that a theory of quantum gravity, possibly like string theory, should be able to explain the singularities classical general relativity has but cannot itself explain,” said Pretorius. “In that sense, singularities then aren’t ‘bad,’ we just need a better theory. However, the problem here is we don’t know what the ‘true’ theory of quantum gravity is. Thus, if there are naked singularities in nature, there would be phenomena in the universe we can’t explain by the theories we have. Some people (like Hawking) view this as ‘anathema,’ and think cosmic censorship is needed to prevent such a disaster; others (like Thorne), think it would be great if there were (benign) naked singularities, as this would give us a direct look into the inner workings of quantum gravity. I’m in the latter camp!” (PhysOrg.com) — While black holes in four-dimensional space-time are stable and can persist for a long time, their higher-dimensional analogues are usually unstable. One such theoretical analogue is a five-dimensional black string, which is unstable to perturbations and tends to decay into different forms. But like all unstable “black objects,” it’s difficult to determine what the end state of the perturbed system might be. Using a new computer code, physicists have been able to simulate the evolution of five-dimensional black strings well beyond earlier studies, leading them to predict that the strings eventually turn into five-dimensional black holes. The researchers ran the simulation until they had to stop due to high computational requirements. But the simulations revealed enough to allow the physicists to estimate that the cascade will terminate at a finite time. As they explained, the curvature of the black holes increases as the string radius decreases, which leads to a naked singularity. last_img read more

New Indiegogo project KUBI turns tablets into telepresence devices

first_imgThe KUBI (“neck” in Japanese) has two “fingers” in the back that support the tablet automatically. Once installed onto the device, the iPad or Bluetooth enabled Android device can be controlled remotely using a web based directional application or via arrows on a keyboard. Pilots can then cause the device to look left and right (up to 300 degrees) and up or down (up to 90 degrees) allowing them to follow the action occurring at a remote location, or to turn to address different people over a dinner or conference table.One possible problem with the device not discussed on the Indiegogo project page or shown in the promotional video is how much noise the device makes as the turning motion involves two gearing systems. As it’s being promoted as a telepresence conferencing tool, it would seem few would be interested if the gear noise is too distracting. Revolve Robotics is looking for $200,000 seed money to start up a manufacturing and sales process for the KUBI. Explore further © 2012 Phys.org (Phys.org)—San Francisco based Revolve Robotics has launched a project on Indiegogo (similar to Kickstarter) looking for funding for its KUBI telepresence device. What’s unique about their project is the projected cost of the device to consumers – $250 instead of the thousands for others currently available for sale. That price differential is due to the fact that KUBI isn’t a robot that wanders around, it’s a tablet computer stand with gears for allowing remote manipulate of the viewing angle. Citation: New Indiegogo project KUBI turns tablets into telepresence devices (2012, December 7) retrieved 18 August 2019 from https://phys.org/news/2012-12-indiegogo-kubi-tablets-telepresence-devices.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. Suitable Technologies set to market new ‘Beam’ Remote Presence Device Telepresence is the use of technology to simulate the experience of being somewhere else in the real world, in real time. To achieve such an effect, robots have been developed that can be driven by pilots situated at a distant location, via the Internet and WiFi. Such robots can be moved to change their orientation to allow for looking around and interacting with others across large or small distances. They typically come equipped with cameras, microphones and speakers.Noting that including the ability to move around has driven the cost of telepresence devices into the thousands of dollars, Revolve Robotics founders and engineers Marcus Rosenthal and Ilya Polyakov chose to take another approach – they’ve cut out the wheels making their device stationary and use the hardware already built into tablet computers to provide the interaction abilities.last_img read more

Evidence found of ultralowvelocity zone possibly feeding Icelandic plume

first_img(Phys.org)—A pair of researchers with the Berkeley Seismological Laboratory in California has found possible evidence of an ultralow-velocity zone (ULVZ) feeding the Icelandic plume. In their paper published in the journal Science, Kaiqing Yuan and Barbara Romanowicz describe using earthquake data to gain a better perspective on the ULVZ and its possible role in the development of Iceland and parts of Norway and Scotland. Citation: Evidence found of ultralow-velocity zone possibly feeding Icelandic plume (2017, July 28) retrieved 18 August 2019 from https://phys.org/news/2017-07-evidence-ultralow-velocity-zone-possibly-icelandic.html ULVZs were first discovered in 1996, and ever since, then they have been a subject of study by seismologists around the world. While it is still not clear exactly what they are made of, prior research showed that they are “blobs” of material that sit at the top of the border between the core and the mantle. Currently, it is believed that there are somewhere between 10 and 20 of them, and each is composed of different materials—researchers found this out by noting that seismic waves travel through them approximately 30 percent more slowly than other parts of the mantle. Because the ULVZs are approximately 2,800 km beneath the surface, learning more about them is difficult. In this new effort, the researchers focused their attention on one particular ULVZ—the one that sits directly below Iceland.To learn more about the object of their interest, the team used seismic tomography, an imaging technique—it involves measuring the earthquake-generated waves that move through the Earth. By looking at waves moving through the ULVZ at different angles, they determined its size and form—they report it to be roughly cylindrical, approximately 15 km in height, and 880 km in diameter. They also report that the ULVZ is situated directly below the Icelandic plume, which they note offers strong evidence that the plume is fed by the ULVZ.The researchers also suggest their imaging efforts offer a hint that the material that makes up the ULVZ is likely molten (because of its shape) rather than rock, which, they note, would likely be more irregular. They add that they believe pictures of all of the ULVZs will improve over time as more powerful computers are used, which should give more evidence of their actual makeup. Tomographic imaging shows massive five-fingered Icelandic mantle plume 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. © 2017 Phys.orgcenter_img Iceland. Credit: Jeff Schmaltz, MODIS Rapid Response Team, NASA/GSFC Explore further Journal information: Science More information: Kaiqing Yuan et al. Seismic evidence for partial melting at the root of major hot spot plumes, Science (2017). DOI: 10.1126/science.aan0760AbstractUltralow-velocity zones are localized regions of extreme material properties detected seismologically at the base of Earth’s mantle. Their nature and role in mantle dynamics are poorly understood. We used shear waves diffracted at the core-mantle boundary to illuminate the root of the Iceland plume from different directions. Through waveform modeling, we detected a large ultralow-velocity zone and constrained its shape to be axisymmetric to a very good first order. We thus attribute it to partial melting of a locally thickened, denser- and hotter-than-average layer, reflecting dynamics and elevated temperatures within the plume root. Such structures are few and far apart, and they may be characteristic of the roots of some of the broad mantle plumes tomographically imaged within the large low-shear-velocity provinces in the lower mantle.last_img read more

Anthem for Delhi film fest launched

first_imgA special anthem, Yeh Dilli hai, capturing the essence of the Capital was launched in the city on Wednesday for the first edition of the Delhi International Film Festival (DIFF) 2012, to be held here from 21 December. The song, penned by Rani Malik, and sung and composed by Ravinder Singh, was launched in the presence of veteran actress Sharmila Tagore, who will receive during the fest the lifetime achievement award for her contribution to cinema. Also Read – ‘Playing Jojo was emotionally exhausting’ Yeh Dilli hai is a peppy number, and its video features key areas of the Capital, including Qutub Minar, Jantar Mantar and Lutyen’s Delhi. It also features new facets of the city — the metro and the Buddh International Circuit. ‘We have never had a song for Delhi per se. Through this anthem, we have tried to give a song to our city. It is a very rhythmic number and will make people tap their feet at once,’ Ram Kishore Parcha, president of DIFF, said. Also Read – Leslie doing new comedy special with Netflix Sharmila was impressed with the song too.‘I like the way Parcha was so enthusiastic about the song and when he said, ‘It will make everyone tap their feet’, I thought it was quite an exaggeration. But I liked the song. It shows the passion behind it,’ she said. The video of the song, Sharmila said, was ‘modestly created’. Nevertheless, it was worthy of appreciation, she added.DIFF 2012, which will conclude 27 December, will showcase a mix of 174 films from 32 countries. Centenarian Zoya Sehgal will be conferred the Minar-e-Dilli award at the extravaganza, which is scheduled to host a melange of filmmakers from across the world.last_img read more

One killed one injured after being hit by ambulance

first_imgKolkata: A 33-year-old man was killed in a road accident where he was hit by an ambulance that was driven by a 17-year-old. The incident took place at Lords More near Lake area in South Kolkata at 2 am on Sunday. Police said the victim Tamal Dutta (33) was a resident of Selimpur Road at Garfa. After preliminary investigation, police came to know that the boy was in an inebriated state and he was driving the ambulance in a negligent manner. He couldn’t control the vehicle and hit the victim. Another person, who was standing close to the victim, was also hit. But he received minor injuries. Tamal was first taken to MR Bangur Hospital and later shifted to SSKM Hospital. He succumbed to his injuries on way to the private nursing home.last_img read more

Indian Solo Arts at its best

first_imgMonsoons are always special for Kolkata because apart from the culinary delight, the city reaches its cultural crescendo with Monologues, India’s only solo arts festival.Presented by Phreedom 4 Ever, a leading marketing communication company (founded by Chaity Ghosh), Monologues began in 2012 and have hosted legendary artists like Chapal Bhaduri, Saoli Mitra, Bijoylakshmi Barman, Mahabanoo Modi Kotwal, Mita Vashist and many others. It is conceptualized and curated by popular arts personality Sujoy Prasad Chatterjee.  Also Read – ‘Playing Jojo was emotionally exhausting’He said, “This is a multi-disciplinary approach to blend different forms of talent in one single festival. The journey has been inspiring to say the least and this solo arts fiesta has truly achieved national acclaim.” Monologues is a pioneer in the Indian arts scene in many ways. One that remains striking is a segment dedicated to youth called The Solo Room, which is usually an off-proscenium act comprising stand-up, poetry slams, music solos and even instrumental singles. Also Read – Leslie doing new comedy special with NetflixMonologues 2015 shall kick-start on July 25 at Uttam Mancha. Legendary theatre personality Rudra Prasad Sengupta shall flag off the festival with a solo play-reading. A playwright, an actor, and founder of Nandikar, a leading theatre society in the cultural kaleidoscope of the country, Sengupta shall enthrall the audience with his energy and dramatic overtones. The Park shall feature actor Riddhi Sen in a theatre act, acclaimed musician Shubhayu Sen Majumder in an Esraj solo followed by Chandrabindoo frontman and filmmaker Anindya in a solo vocal. The closing act happens on July 27th at Gyan Manch with a solo called Untitled, presented by Lushin Dubey, internationally reputed theatre personality from Delhi.  This act is a perfect tribute to gender emancipation—a power-packed closure to the three-day arts ensemble. “This festival is the perfect way to celebrate the singular power in arts, and what can be more delightful than having two stalwarts of theatre open and close the ensemble. As an artist, this is my repayment to my passion and profession”, says Sujoy Prasad Chatterjee, artistic director of the festival. “Monologues is one of the most preferred art mediums to showcase brand and artistic synergy—culture cuts across commerce to lead customer delight and the corporate enhances its message of communication. We at Phreedom 4 Ever believe that Monologues is our tribute to artists in a unique way—the right integration of brand communication,” says Chaity Ghosh, Chief Mentor, Phreedom 4 Ever.last_img read more

Beware Antioxidants can cause cancer to spread faster

first_imgAntioxidants double the rate of metastasis, the spread of cancer from one part of the body to another, in malignant melanoma, the most perilous type of skin cancer, warns a new study.Found in many nutritional supplements, antioxidants are widely marketed as a means of preventing cancer.The results of this study suggest that people with cancer or an elevated risk of developing the disease should avoid nutritional supplements that contain antioxidants. “We have demonstrated that antioxidants promote the progression of cancer,” said one of the researchers Martin Bergo from Sahlgrenska Academy at University of Gothenburg in Sweden. Also Read – ‘Playing Jojo was emotionally exhausting’Antioxidants protect healthy cells from free radicals that can turn them into malignancies but may also protect a tumour once it has developed, the findings showed. Researchers at Sahlgrenska Academy demonstrated in January 2014 that antioxidants hastened and aggravated the progression of lung cancer. Mice that were given antioxidants developed additional and more aggressive tumours.Experiments on human lung cancer cells confirmed the results. Given well-established evidence that free radicals can cause cancer, the research community had simply assumed that antioxidants, which destroy them, provide protection against the disease.  Also Read – Leslie doing new comedy special with NetflixBut because the lung cancer studies called the collective wisdom into question, they attracted a great deal of attention. The follow-up studies at Sahlgrenska Academy have now found that antioxidants double the rate of metastasis in malignant melanoma in mice. “The antioxidant boosted the ability of the tumour cells to metastasise, an even more serious problem because metastasis is the cause of death in the case of melanoma. The primary tumour is not dangerous per se and is usually removed,” Bergo noted.Experiments on cell cultures from patients with malignant melanoma confirmed the new results. The findings appeared in the journal Science Translational Medicine.last_img read more

APS Shankar Vihar clinches top spot in Army Day Quiz

first_imgThe Army Day Quiz Competition was held at Zorawar Auditorium, Manekshaw Centre on Thursday as part of the 68th Army Day 2016 Celebrations. The event received overwhelming response from the school children with 98 teams from 68 schools taking part in the event including schools from Digboi, Assam and Lucknow.Namita Suhag, President Army Wives Welfare Association was the chief guest at the event, which was attended by other senior dignitaries and ladies from the Army establishment. Aditya Nath Mubayi, renowned Quiz Master conducted the entire event and ensured involvement and participation of the entire audience.  Also Read – ‘Playing Jojo was emotionally exhausting’The event was conducted with a preliminary test, after which six teams reached the final stage of the uiz. The entire Quiz was keenly contested and witnessed a very high standard of participation from all the teams. The team from Army Public School, Shankar Vihar (Delhi Cantonment) were the winners of the competition and Army Public School, Hisar was the runner up of the competition who were both awarded with trophies, medals and cash prizes.The Quiz was educative, knowledgeable and an interesting experience for the audience. The event was conducted as a prelude to the Army Day Celebrations this year and went a long way to etch an impression in the minds of the future generations of the country on the Indian Army’s legacy of Courage, Valour and Sacrifice.last_img read more

Mamata invites German biz honchos to invest in Bengal

first_imgKolkata: Chief Minister Mamata Banerjee invited German investors and business leaders to come and attend the Bengal Global Business Summit scheduled to be held in 2019 amid discussions during a meeting, jointly organised by IHK, Frankfurt, Indo-German Chamber of Commerce, FICCI and the government of West Bengal in Frankfurt, Germany.Top business leaders from Germany along with a delegation of nearly 50 business and industry leaders from Bengal took part in the meeting. Also Read – Rain batters Kolkata, cripples normal lifeExtensive deliberations were held on the prospects of doing business in Bengal with particular focus on possible investments from Germany in the state in sectors like industrial infrastructure and logistics hub, engineering and foundry hub, petrochemical and polytechnic hub, urban development, IT and ITeS, financial technology, agro and food processing, textiles and tools, leather, transport, power, tourism and social infrastructure projects.Possibilities of investment in Micro, Small and Medium Enterprises, which is a key economic activity in Germany, was also extensively discussed. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedThe welcome address was delivered by Mukta Dutta Tomar, Ambassador of India, to the Federal Republic of Germany.Addressing the meet, Mamata Banerjee said Bengal is the ideal destination for investment. “It is the gateway to the North-eastern states, Bhutan, Nepal and Bangladesh. It takes less than an hour to reach Nepal, Bhutan and Bangladesh by air. Also, Singapore, Bangkok and Myanmar can be reached easily from the state. So position wise, it is the ideal destination — easily accessible, facilitated by proper transportation,” she maintained. Banerjee said the state government is ready to provide all the privileges and provisions to the investors. “We have land bank, land-use policy and the government is ready to provide all possible assistance.” She said there is no dearth of talent in Bengal. “Go anywhere in the world and you will find talented people from Bengal. Come to Bengal and use them,” she urged the industrialists.Banerjee maintained that in skill development, Bengal is the number 1 state in India. The state government provides scholarships to lakhs of students. In e-governance, the state has done remarkably well. Bengal’s Kanyashree scheme has already gained worldwide appreciation.Recollecting Bengal’s long association with Germany, she said Swami Vivekananda, Rabindranath Tagore and Netaji Subhas Chandra Bose had visited Germany and Netaji even married a German lady. “Like the Germans, the people from Bengal are huge football fans. We respect the German football teams and several players are highly respected in Bengal and also have a large fan-following.”Earlier, in the day she stated that she had come to Germany to acquire investments in engineering and while in Italy her main target would be to establish business with the leather industry. “Many leather industries from Kanpur are planning to shift to Bengal and this will give job opportunities to lakhs of youths.”The discussion on Opportunities in West Bengal and Industry Experiences was presided over by state Finance minister Amit Mitra. Among the participants were Jurgen Ratzinger, Managing Director, International Business IHK Frankfurt. Dirk Matter, director IGCC Dusseldork; Oliver Wack, area manager; Foreign Trade Department East and South Asia trade policy.Industrialists from Bengal included Purnendu Chatterjee, Rudra Chatterjee, Tarun Jhunjhunwala, Sanjay Puri, K K Bangur and Mayank Jalan who shared their experiences of doing business in Bengal.last_img read more