In work that may help solar panels become a more viable source of mainstream power, a research group has created a dye-based solar cell with a high efficiency and high stability, and that lacks the volatile chemicals used in similar cells. This is a combination so far lacking in the newest solar-cell prototypes. The group, including researchers from the Changchun Institute of Applied Chemistry at the Chinese Academy of Sciences (CAS) and the Swiss Federal Institute of Technology, was studying a new type of solar cell that is being widely researched across the globe, one made of bendy, low-cost, lightweight organic materials rather than rigid, pricey, and often heavy inorganic materials. “We have uncovered new findings on old solar-cell materials and created high-performance cells,” said Peng Wang, a researcher in the Changchun Institute of Applied Chemistry and the study’s corresponding scientist, to PhysOrg.com.The type of organic solar cell Wang and his colleagues improved contains three key parts. The first two components are a semiconductor, such as silicon, and an electrolytic liquid—a conducting solution commonly formed by dissolving a salt in a solvent liquid, such as water. The semiconductor and electrolyte work in tandem to split the closely-bound electron-hole pairs produced when sunlight hits the cell, called excitons (holes are positively charged electron vacancies).The third component is the source of these photo-induced charge carriers, a photosensitive dye that gives the solar cells their name: “dye-sensitized,” with the most common dye being iodide. In addition, a nanomaterial is also often used to hold the dye molecules in place like a scaffold.The highest efficiency solar cell ever made is dye-sensitized, with an efficiency of 11 percent, meaning 11 percent of the solar energy is converted to electrical energy (compared to 8.2 percent achieved by Wang and his group). But the highest efficiency dye-sensitized cells also contain volatile solvents in their electrolytes that can permeate across plastic (i.e. organic compounds) and also present problems for sealing the cells. Cells that contain these solvents are therefore unattractive for outdoor use due to potential environmental hazards. So while they perform well, they have serious drawbacks.Researchers have developed solar cells that use solvent-free electrolytes, but the cell efficiencies are too low.The cell developed by Wang and his group avoids these issues using a “formulation” they developed. To create their electrolyte, they took three solid salts and mixed them to form a “fascinating” liquid, says Wang. The resulting electrolyte has an impressive conductivity as well as the favorable stability properties of all three salts.”The performance of our solar cell now matches that of cells that use volatile solvents,” said Wang. “This is an important step toward the production of large-scale outdoor dye-sensitized solar cells.”Citation: Yu Bai, Yiming Cao, Jing Zhang, Mingkui Wang, Renzhi Li, Peng Wang, Shaik M. Zakeeruddin and Michael Grätzel 29 June 2008 Nature advance online publication, DOI:10.1038/nmat2224Copyright 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. 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 further Citation: Researchers Produce Best-Yet Dye-Based Solar Cells (2008, July 31) retrieved 18 August 2019 from https://phys.org/news/2008-07-best-yet-dye-based-solar-cells.html 2-D perovskite materials found to have unique, conductive edge states
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. © 2011 PhysOrg.com Citation: Study finds European starlings flocking patterns similar to metals being magnetized (2012, March 14) retrieved 18 August 2019 from https://phys.org/news/2012-03-european-starlings-flocking-patterns-similar.html Prior research by the same team regarding the velocity of the birds in a flock showed that if just a single bird changed its speed, that change would propagate out to all the other birds in the flock. In this new research, the team focused on orientation. They wanted to know how individual movements of birds in the flock caused changes in the direction of the flock as a whole.To find out, they set up multiple cameras around Rome, where the huge size of starling flocks is legendary. They took both video and stereometric stills which produce 3D imagery to allow them to capture the positions of birds in a flock as well as to project where they were going and how fast.In so doing, they discovered two things. The first is that a change in path by one bird impacts exactly seven birds surrounding it, regardless of the size of the flock. The second is that changes in flight path for the flock as a whole happens very similarly to the way single electron spins within a metal line up when a magnetic field is created.The first finding demonstrates that birds having neighbors is what is important to the flock, not how close they are. The seven birds that are impacted by the movement of one bird, then cause a change in the seven birds around each of them and so on until the entire flock has changed its alignment.The second finding demonstrates that at least some of the ways birds move in a flock can be defined mathematically, which means other models may be found as well. If so, they may lead to predicting how a flock will respond in various scenarios, which when combined with the way the birds impact their neighbors, may finally solve the age old mystery of how they fly in flocks the way they do. Explore further More information: The study will be published in PNAS at DOI:10.1073/pnas.1118633109 (not available at this moment yet). Image: Wikipedia. (PhysOrg.com) — Scientists and amateur enthusiasts alike have long been fascinated by the abilities of some groups of animals to move in lockstep with one another, most specifically with schools of fish and flocks of birds. Now, new research by a team of researchers studying the flocking abilities of European starlings has shown that some of their abilities might be mathematically defined, and that the ability of the birds to change directions almost simultaneously follows the same model as metal when it becomes magnetized. The team is set to publish the results of their study in the Proceedings of the National Academy of Sciences. Journal information: Proceedings of the National Academy of Sciences Starling flocks fly like a single entity (w/ Video)
More information: Stabilizing Rabi oscillations in a superconducting qubit using quantum feedback, Nature, 490, 77–80 (04 October 2012) doi:10.1038/nature11505AbstractThe act of measurement bridges the quantum and classical worlds by projecting a superposition of possible states into a single (probabilistic) outcome. The timescale of this ‘instantaneous’ process can be stretched using weak measurements, such that it takes the form of a gradual random walk towards a final state. Remarkably, the interim measurement record is sufficient to continuously track and steer the quantum state using feedback. Here we implement quantum feedback control in a solid-state system, namely a superconducting quantum bit (qubit) coupled to a microwave cavity. A weak measurement of the qubit is implemented by probing the cavity with microwave photons, maintaining its average occupation at less than one photon. These photons are then directed to a high-bandwidth, quantum-noise-limited amplifier, which allows real-time monitoring of the state of the cavity (and, hence, that of the qubit) with high fidelity. We demonstrate quantum feedback control by inhibiting the decay of Rabi oscillations, allowing them to persist indefinitely. Such an ability permits the active suppression of decoherence and enables a method of quantum error correction based on weak continuous measurements. Other applications include quantum state stabilization, entanglement generation using measurement, state purification and adaptive measurements. Explore further 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. Journal information: Nature Physicists seek to quantify macroscopic quantum states Rabi oscillations and feedback. Credit: Nature, 490, 77–80 (04 October 2012) doi:10.1038/nature11505 (Phys.org)—As understood in the field of quantum mechanics, objects are able to exist in more than one state at a time, a property known as superposition. Measuring such states is a challenge however, as doing so causes the superposition property to be destroyed, at least according to classical theory. Now, physicists working at the University of California have found a way to cheat the system, so to speak. They have, as they describe in their paper published in the journal Nature, found a way to take a quick peek at the oscillation of a qubit, without destroying its superposition property. Citation: Researchers devise a means to ‘gently’ measure qubit without destroying superposition (2012, October 4) retrieved 18 August 2019 from https://phys.org/news/2012-10-gently-cubit-superposition.html © 2012 Phys.org The whole idea behind superposition was famously explained by Erwin Schrödinger, who suggested it could be thought of as a cat in a box that also contained a radioactive atom . The decay of the atom could not be known without opening the box and checking—an act that would change its state. From a perspective outside the box, the cat was apparently both dead and alive at the same time. In this new work, the researchers suggest that only partially opening the box gives them some insight into the box’s inner conditions without disturbing its contents. To make that happen, the team employed a feedback control mechanism whereby a superconducting qubit was coupled to a microwave cavity. It was then pushed into a superposition state by cycling its state back and forth between 0 and 1, repeatedly hitting all possible mixtures. Once there, they measured its oscillation frequency. This measurement was too weak to destroy the oscillation but strong enough to cause slight change. Using the measurement taken, the team very quickly calculated, and then created, an exact opposite charge which they injected back into the system, causing the oscillation to return to its former frequency: they had managed to measure a tiny part of the system without destroying the superposition state, a feat never before achieved in the lab. In order to carry out this experiment, the team had to first develop an amplifier that would allow them to inject the charge back into the system without making other changes—no small thing. This development led to the first instance of a qubit being measured, if only partially, without changing its state. The researchers suggest their technique might be used as a means of error control in a quantum system, i.e. computer, by allowing qubits to exist in a superposition state for longer periods of time.
More information: Three Classes of Newtonian Three-Body Planar Periodic Orbits, Phys. Rev. Lett. 110, 114301 (2013) DOI:10.1103/PhysRevLett.110.114301 (on ArXiv)AbstractWe present the results of a numerical search for periodic orbits of three equal masses moving in a plane under the influence of Newtonian gravity, with zero angular momentum. A topological method is used to classify periodic three-body orbits into families, which fall into four classes, with all three previously known families belonging to one class. The classes are defined by the orbits’ geometric and algebraic symmetries. In each class we present a few orbits’ initial conditions, 15 in all; 13 of these correspond to distinct orbits. Journal information: Physical Review Letters The (translucent) shape-space sphere, with its back side also visible here. Three two-body collision points (bold red circles) – punctures in the sphere – lie on the equator. Credit: Milovan Suvakov, V. Dmitrasinovic / arxiv.org/abs/1303.0181 New horseshoe orbit Earth-companion asteroid discovered Explore further (Phys.org) —Physicists Milovan Šuvakov and V. Dmitrašinović of the Institute of Physics, Belgrade in Serbia have discovered using computer simulations, 13 new solutions to the three-body problem—predicting patterns that describe how three bodies will orbit around each other in space in a repeating pattern. The two describe how they came up with their solutions using computer simulations in their paper published in Physical Review Letters. Citation: Physics duo discover 13 new solutions to Newtonian three-body orbit problem (2013, March 15) retrieved 18 August 2019 from https://phys.org/news/2013-03-physics-duo-solutions-newtonian-three-body.html © 2013 Phys.org 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. When two bodies in space orbit one another, such as a planet and a star, their paths can be easily described by Newton’s laws of gravity—they are elliptical. When another body is introduced, however, things become so complex that scientists have not been able to find a way to predict the sorts of patterns that are possible for a stable system (where they don’t run into one another eventually) to come about. Until now, just three families have been identified: The Lagrange-Euler, the Broucke-Hénon, and the figure-eight.To discover a repeating pattern that describes how three bodies will orbit one another in stable fashion requires some degree of luck, the Lagrange-Euler family for example was discovered by the mathematicians for whom it is named and is demonstrated by the way the sun, Jupiter and the asteroid Trojan orbit one another. Another way requires some degree of brute force—that’s the approach taken in this new effort. The two researchers started with a known solution then changed some of the parameters in their computer simulations and ran the results to see what would happen. As it turned out, their way resulted in the discovery of 13 new families of patterns—stable orbits that eventually lead to all three bodies existing in the same place as they were when the simulation started.Because they found so many new solutions, the two came up with a way to classify them using what they call a shape-sphere to graphically show what the orbits look like and then gave each a name, based on what they thought they resembled: yarn, butterfly, goggles, etc.Thus far, the 13 new families haven’t been tested thoroughly enough to verify that their orbits would remain stable over long periods of time (which would mean holding their pattern despite slight perturbations), however—the researchers plan to do just that as part of their next effort. If it turns out some or all of them can withstand the test of time, then scientists can begin looking for instances of them in real systems and perhaps learning more about those systems as a result.
Some of India’s music industry’s biggest names came forward to raise awareness as well as funds for the Assam floods, at a concert in the Capital, this Sunday evening. The event, spearheaded by composer -singer Vishal Dadlani and Singer Papon, was hosted at the Blue Frog. Apart from Papon and m Vishal Shekhar, singers Arijit Singh, Benny Dayal, Shilpa Rao, Harshdeep Kaur, Neeti Mohan and the Band Indian Ocean came together for the concert called, #ForAssam. Also Read – ‘Playing Jojo was emotionally exhausting’It was a jampacked concert as more than six hundred people turned up for it. The concert was was touted as one of the best singers’ line up for any indoor event in Delhi. The tickets were sold out in just eight hours. ‘The line-up is fantastic and what can be better than listening to your favorite singers on stage while donating for a cause like this? Personally I came here to see Arijit Singh live’, says Amadeep Singh Kalra, a software Engineer. Also Read – Leslie doing new comedy special with NetflixVishal and Papon came up with the idea while talking on twitter a few days back. According to Vishal, ‘All it took was a bunch of phone calls to the best of the best artistes in the country and here they are, for Assam. We think that the catastrophe in Assam wasn’t given as much importance in the media and we are here to raise funds and more importantly, raise voices for Assam.’Papon who hails from Assam said, ‘I couldn’t help much financially, so my medium to help them is Music. Money doesn’t matter, what matters is that people should know of the situation there. North East is a corner and people feel neglected there. People there should know that when they need help, help will come.’ Performing numbers like Allah ke Bande and Roday, Rahul Ram, from the Indian Ocean band said, ‘Since Delhi has more people from the North East, I wish we could have done it on a bigger scale. This is our way of giving back to the people for all the love we have received’.The evening was packed with singers performing back to back to some of the biggest numbers of Bollywood. While some songs made the crowd go crazy, swaying and dancing; some soulful numbers reminded them of the greater cause of why the concert was held. All funds of the concert went to the Chief Minister’s fund and none of the organisers or their partners, claim to have taken any money for the event.
It all started with a thought – How would one know about those missing links of artist’s personal views and ideas, thoughts that have never sprung-up on the surface, at a social gathering or a public viewing. In December 2013, Exhibit 320 had a critically effective launch of this project and now they leap onto the second chapter of Artchiving; an artists’ perspective. A project cum exhibit theorized by Ranjita Chaney. Participating Artists will be MuktinathMondal, Pooja Iranna, Probir Gupta, Remen Chopra, VibhaGalhotra. Also Read – ‘Playing Jojo was emotionally exhausting’Artchiving; an artist’s perspective focuses on thoughts and opinions about an artist’s current state of mind, documented over a period of time, seeing them evolve addressing to same issues and ideas. To express largely, this is an effort of presenting art and practice to a broader audience through personal interaction. By documenting, not artists’ works and beliefs alone but their personal and private thoughts in their naked studios and individual places. Also Read – Leslie doing new comedy special with NetflixThe main aim is to create an archive of artist’s practice and their beliefs, attempting at a resourceful exchange of dialogues between artists’ practices and influences in their ongoing journey. Seeing finished works on display from every artist, interviews about their practice and thesis on their work style, is not sufficient. The basic question is ‘How is it done’, ‘what is the artist thinking when making or working on a piece and many more?’ Hence, an attempt to collect imagery along with words and information for our archives from this artistic journal.Where : Exhibit320, When: 22 November to 15 January
Kolkata: The British Council Summer School has come back to the city once again. The school has a lot to offer to children aged between 7-14 years, enhancing communication, creativity and confidence.After coaching 650 students in Kolkata in 2017 through engaging methodologies, the Summer School aims to make learning a fun process for children this year as well.Children aged between 7-14 years can spend their summer holidays discovering their inner creativity in fun and engaging ways, through a mixture of games, projects, drama and communicative activities at the British Council Summer School. The programme also encourages students to interact in pairs, small groups and whole class situations, improving their English fluency and confidence. Also Read – Heavy rain hits traffic, flightsThis year will see British Council run two themes during the Summer School: Explorers (through a virtual trip around the world, children will travel to one country each day, learn about different cultures, develop language skills and build confidence) and Media Magic (children will explore communication channels such as the radio, television and the internet. They will learn how to write blogs, create an advertisement and newspaper report).Debanjan Chakrabarti, Director, East and Northeast, British Council, said, “Our English language teaching centre in Kolkata is an exciting hub of activity all summer. The year 2018 marks the 70th anniversary of the British Council’s presence in India.”
The Right to Information Act allows for a public authority to disclose records which are otherwise exempt from disclosure if public interest outweighs the harm protected.Activist Subhash Agrawal had sought from the Prime Minister’s Office the records related to the freedom fighter and leader of the Indian National Army to clarify the mystery surrounding his alleged death in a plane crash 70 years back.Agrawal had also asked for information of the steps taken by the top office to make such records public and the action taken on requests seeking such documents. Also Read – Need to understand why law graduate’s natural choice is not legal profession: CJIBut toeing the line of the UPA government, the PMO had cited an exemption clause in the RTI Act which allows withholdnig of information that could prejudicially affect relations with a foreign country. The PMO, however, did not even give the names of the countries with which the relations may get affected once the said information is made public.When the first appeal was filed before a higher officer in the top office, the Appellate Authority, Krishan Kumar, had rejected the argument that public interest would be served through the disclosure of the documents related to Bose’s death.Home Minister Rajnath Singh, while campaigning for polls, had claimed that there was a larger public interest involved in the disclosure of the documents, but the PMO under Modi does not seem to be in agreement.
Two incidents in the recent past have brought back the spectre of extra-judicial killings. The first incident refers to the alleged encounter killing of a Delhi-based businessman by officers of the Delhi Police Special Cell. The second incident refers to an earlier encounter killing of 20 red sandalwood smugglers near Tirupati in Andhra Pradesh by officers from the Andhra Police. Since both incidents are currently under judicial scrutiny, it would be unwise to arrive at judgements surrounding their culpability. However, rising evidence against the versions presented by both sets of police forces has left numerous observers, from both the political class to civil society, rather disturbed. Also Read – Working on improving tiesIn the first case, reports have emerged that 10 days before the Delhi-based businessman was gunned down in an alleged encounter, the Delhi Police Special Cell had told a local court that neither an FIR nor a complaint was received against him. This discovery flies in the face of the Special Cell’s claim that the slain businessman was wanted in several cases and had been on the run from the law. With reference to the encounter killing of 20 red sandalwood smugglers, news reports have emerged that the many of the slain were possibly tortured before being murdered. According to the police, these 20 labourers had attacked them with sickles, axes and stones and the police had gunned them down in self-defence. This claim is perplexing on many levels. Also Read – Political parties and our RepublicThe police was not involved in a skirmish with highly trained and heavily armed militants; they were dealing with a group of underpaid minimum wage labourers. If it was indeed in self-defence as they claim, where are the injuries of the task force members? Reportedly, only two members of the task-force were injured. Further disheartening is the inefficacy of our legal system in resolving encounter killings. According to government figures, out of 555 recorded encounter killings between 2009 and 2013, only 144 cases were been resolved. Irrespective of a final judgement on both incidents, one cannot rationalise extra-judicial killings, without going down a very slippery moral slope. Once the State and its police go down the path of extra-judicial killings, it is likely to make its way towards tyranny. It is impossible to condone summary executions, especially if they are conducted by those who consider themselves to be the guardians of the law. Instead of summary executions, the State, especially its police, must follow the due process of law and subject the suspect to a trial process. Even Ajmal Kasab, one the perpetrators behind the heinous terror attack in Mumbai, was subjected to a trial process. According to respected political commentator Praful Bidwai, “Civil liberties are too valuable to be subordinated to reasons of state without undermining democracy”. The truth behind both these murky incidents, therefore, must come through soon.
Kolkata: Three persons were killed and two others injured when a car hit a road side tree near Golsi Chowmatha area in East Burdwan on Friday.The injured persons are stated to be serious. They have been undergoing treatment in Burdwan Medical College and Hospital. The police are yet to confirm the identity of the deceased persons. According to the preliminary investigation, police said the accident occurred because a tyre of the vehicle had burst. As the car was at a high speed, the driver could not control the vehicle. Also Read – Rain batters Kolkata, cripples normal lifeThe incident triggered traffic congestion in the area for nearly one hour. According to the police, the vehicle was carrying five passengers including the driver. They said the victims were returning to Burdwan from Joyrampur at around 11 am when the persons met with the accident. The vehicle was headed towards Galsi Chowmatha area when it rammed into a roadside tree. Locals heard a loud thud and rushed to the spot. They found the frontal portion of the vehicle completely damaged and the victims were trapped inside the mangled car. Some of the locals managed to rescue three victims who were sitting on the back seat. One of the three passen gers succumbed to his injuries in the hospital, while the driver and another person on the front seat died on the spot. Police removed the two bodies from the car with help of a gas cutter. Police are investing other possible angles which might have led to the incident. The investigating officers collected samples from the damaged car for investigation. According to sources in Burdwan Medical College and Hospital, the two persons admitted have multiple injuries on their bodies. They have been kept under close monitoring. One of the injured victims also received head injuries in the accident. Various medical tests have been performed on the victims on Friday.Police suspect that the car was running at a speed of anything between 100-120 km per hour. They have started a detailed probe in this regard. The situation was brought under control by seniorpolice officers.