Explore further © 2010 PhysOrg.com Citation: New charging method could greatly reduce battery recharge time (2010, March 11) retrieved 18 August 2019 from https://phys.org/news/2010-03-method-greatly-battery-recharge.html This figure shows the fraction of non-intercalated lithium ions per time, with the different colors representing different amplitudes of the applied oscillating field (A = 5 kCal/mol). The denominator in the exponential is the average intercalation time in nanoseconds, showing that a larger amplitude field speeds up ion intercalation. Credit: Hamad, et al. Increasing Electric Car Battery Performance More information: Ibrahim Abou Hamad, M. A. Novotny, D. Wipf, and P. A. Rikvold. “A new battery-charging method suggested by molecular dynamics simulations.” Available at arxiv.org. Doi: 10.1039/b920970k.via: Technology Review (PhysOrg.com) — Part of the headache of having to constantly recharge batteries is not just how often they need to be charged, but also the time it takes to charge them. In a new study, researchers have proposed a charging method that could greatly reduce the charging time of lithium-ion batteries, which are used in everything from electronic devices to electric vehicles. The new method uses an additional oscillating electric field (besides the charging field) that should be capable of charging a lithium-ion battery in a fraction of the time compared with traditional methods. Researchers Ibrahim Abou Hamad from Mississippi State University and coauthors have developed the new charging method thanks to revolutionary developments in molecular dynamics simulations. In their study, the researchers simulated the lithium-ion battery-charging process by simulating the intercalation (i.e. “insertion”) of lithium ions into the battery’s graphite anode. Although intercalation is just one part of the charging process (along with diffusion), it dominates the charging time.In the charging process, lithium ions first diffuse within the battery’s electrolyte until they reach the graphite anode. At this interface, ions must overcome an energy barrier in order to be intercalated into the anode. In their simulations, Hamad and his team found that an additional oscillating electric field can lower this energy barrier, enabling lithium ions to intercalate more quickly into the anode. The oscillating field also increases the diffusion rate, which helps further reduce the overall charging time, albeit to a lesser extent.Specifically, when the scientists applied an oscillating square-wave field with a frequency of 25 GHz and an amplitude of 5 kCal/mol to the graphite sheets in the anode, the lithium ions intercalated into the graphite sheets within an average time of about 50 nanoseconds. By changing the amplitude of the oscillating wave, the researchers found that they could further improve charging time by lowering the energy barrier and speeding up intercalation. Their simulations showed that the dependence of the intercalation time on the amplitude is exponential, meaning that a small increase in amplitude leads to a large increase the intercalation speed, which offers the potential for very fast charging times. In the future, the researchers plan to further investigate the new method, including analyzing how changing the frequency of the oscillating field effects the charging time. They noted that the new method might provide an increase in battery power densities, as well. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
The researchers, Parthiban Santhanam and coauthors from MIT, have published their study in a recent issue of Physical Review Letters.As the researchers explain in their study, the key to achieving a power conversion efficiency above 100%, i.e., “unity efficiency,” is to greatly decrease the applied voltage. According to their calculations, as the voltage is halved, the input power is decreased by a factor of 4, while the emitted light power scales linearly with voltage so that it’s also only halved. In other words, an LED’s efficiency increases as its output power decreases. (The inverse of this relationship – that LED efficiency decreases as its output power increases – is one of the biggest hurdles in designing bright, efficient LED lights.)In their experiments, the researchers reduced the LED’s input power to just 30 picowatts and measured an output of 69 picowatts of light – an efficiency of 230%. The physical mechanisms worked the same as with any LED: when excited by the applied voltage, electrons and holes have a certain probability of generating photons. The researchers didn’t try to increase this probability, as some previous research has focused on, but instead took advantage of small amounts of excess heat to emit more power than consumed. This heat arises from vibrations in the device’s atomic lattice, which occur due to entropy.This light-emitting process cools the LED slightly, making it operate similar to a thermoelectric cooler. Although the cooling is insufficient to provide practical cooling at room temperature, it could potentially be used for designing lights that don’t generate heat. When used as a heat pump, the device might be useful for solid-state cooling applications or even power generation.Theoretically, this low-voltage strategy allows for an arbitrarily efficient generation of photons at low voltages. For this reason, the researchers hope that the technique could offer a new way to test the limits of energy-efficiency electromagnetic communication. Explore further Citation: LED’s efficiency exceeds 100% (2012, March 5) retrieved 18 August 2019 from https://phys.org/news/2012-03-efficiency.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.
Kolkata: The state Disaster Management and Civil Defence department has decided to give satellite phones to district authorities, to ensure uninterrupted communication even during natural calamities and other emergency situations.According to a senior official of the state Disaster Management and Civil Defence department, it has often been found that mobile phones lose network connection when there is a natural calamity.In a bid to ensure that inter-district communication and communication with the state government headquarters stay uninterrupted at the time of an emergency, the district authorities will be provided with satellite phones. Also Read – Heavy rain hits traffic, flightsSources said that initially, 16 satellite phones will be distributed among the districts and gradually, connectivity using satellite phones will be established with all the districts.The officials from districts have also been provided with all sorts of training necessary to operate satellite phones. It will ensure uninterrupted connectivity with the districts, even during an emergency.It may be mentioned that the state Disaster Management and Civil Defence department has also planned to set up Quick Response Teams (QRT) for each district, to ensure better help to people during an emergency situation. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedThe decision to set up QRTs was taken after a District Disaster Management Authority (DDMA) came into existence in each district.Civil Defence Volunteers will be part of the QRTs and the number of volunteers in each team will be depending on the number of sub-divisions in the district. There will be around 25 volunteers for each sub-division. This comes at the time when the department has become immensely successful in reducing the number of deaths due to lightning, by introducing a system in which people get alerted at least 45 minutes before lightning strikes an area. It is helping people to reach a safe place in the time they are getting after receiving the alert.
Kolkata: After filmmaker-actor-singer Farhan Akhtar pointed out a “glaring error” made in a West Bengal school book which depicted him as legendary athlete Milkha Singh, Trinamool Congress MP Derek O’Brien on Monday said the book was not part of government schools’ curriculum. “Thanks Farhan. Ref the wrong pic of Milkha Singh. Checked with education minister of state. He tells me it isn’t a textbook for government schools. Nor is it published by government,” he said in a tweet. Also Read – Rain batters Kolkata, cripples normal life “Trying to track the private publishing company. They ought to correct the mistake in future editions,” the MP added. Farhan, who played the title role in the Indian track and field legend Milkha Singh’s biopic “Bhaag Milkha Bhaag”, replied: “Appreciate your response. Tagged you since you take education very seriously.” On Sunday, Farhan had tweeted, “To the Minister of School Education, West Bengal. There is a glaring error with the image used in one of the school text books to depict Milkha Singhji. Could you please request the publisher to recall and replace this book? Sincerely”. Among his many achievements, Mikha Singh was the first Indian to clinch an individual athletics gold medal at the Commonwealth Games in 1958.
The Embassy of the Republic of Korea, New Delhi supported by the Korean Consulate in Kolkata hosted “Tasty Korea – a Korean Musical Night” at G D Birla Sabhaghar, Kolkata. The event was graced by senior diplomats from the Korean Embassy in New Delhi, the Honorary Consul General of Korea in Kolkata, the diplomatic and consulate community and also professors and students from various universities and schools in Kolkata.This musical night showcased the spectacular new brand of “BIBAP” which is an upgraded musical called “CHEF”. “BIBAP” has been a tremendous draw for the past six years since its premiere in 2011. One can experience 100 % live beat-box and rediscover the art of B-Boying and Acapella with no special effects or recording. This dynamic B-Boying showcases the process of food-making. The upgraded musical “CHEF” is a fun packed show with rich sounds and vivid visualizations. Every facial expression and movement of the performers is thoroughly calculated, naturally incorporating slapstick comedy in the show. Also, ‘CHEF’ presents a legacy of non-verbal performances and is also interactive as it encourages participation from audience members, which in turn generates unexpected hilarity. Also Read – Add new books to your shelfAccording to a representative from the Korean Embassy, “This musical event will boost the ‘nation brand’ in the cultural capital of India which is Kolkata. “Hallyu” or “Korean Wave” is fast becoming a buzz word globally. The term basically refers to various facets of Korean Culture, including Korean music, dance, dramas, movies, food, fashion and cosmetics that are becoming popular across Asia and other parts of the world.”The Korean musical night ended with a raffle where everyone was given a chance to win attractive prizes. The event also promoted the “XXIII Olympic Winter Games – The Pyeong Chang 2018 Olympic and Paralympics.Regardless of one’s prior knowledge about Korea, this Musical Opera brought unique opportunities that made one discover new interests in Korean culture.
Kolkata: The Wildlife Wing of the state Forest department seized 20 birds of three scheduled species of parakeets from Galif Street on Sunday.No one could be arrested as offenders probably had sensed danger and abandoned the cages full of birds to save themselves. According to sources, acting on a sources information sleuths from Forest department conducted a special raid on Sunday morning at Galif Street. Forest department officials posed as prospected buyers of pets and was taking a round of the pet market for possible catch. After almost an hours, some of them noticed few cages covered with pieces of cloth which were abandoned. Suspecting something fishy, sleuths started keeping strong vigil on the cages. But after waiting for a long time no one came to pick up those cages. Also Read – Rs 13,000 crore investment to provide 2 lakh jobs: MamataLater, forest officials removed the cloth pieces and found three species of birds identified as rose ringed parakeets, alexandrine parakeets and grey headed starling. Immediately, the birds were seized and it was found there are 20 birds from the schedule of forest department regulations which are banned for trade. Later, the birds were taken to the wild life rehabilitation centre in Salt Lake. A case has been lodged. A forest officials said they are continuously trying to inform people not to buy any scheduled birds as it is illegal. The aim is to save and conserve wildlife by awareness of common people. Earlier this month, state Forest department and Wildlife Crime Control Bureau (WCCB) jointly carried out a raid at Galif Street, after the officials got a tip off that several endangered species of birds were being sold by a few persons. A large number of birds were recovered during the raid and nine persons are arrested by the officials of forest department and WCCB.