© 2017 Phys.org (Phys.org)—A team of researchers affiliated with institutions in the U.S., China and the Kingdom of Saudi Arabia has developed a new type of porous graphene electrode framework that is capable of highly efficient charge delivery. In their paper published in the journal Science, the group describes how they overcame traditional conflicts arising between tradeoffs involving density and speed to produce an electrode capable of facilitating rapid ion transport. Hui-Ming Cheng and Feng Li with the Chinese Academy of Sciences offer a Perspective piece on the work done by the team in the same journal issue, and include some opinions of their own regarding where such work is likely heading. Journal information: Science This visualisation shows layers of graphene used for membranes. Credit: University of Manchester Citation: A holey graphene electrode framework that enables highly efficient charge delivery (2017, May 12) retrieved 18 August 2019 from https://phys.org/news/2017-05-holey-graphene-electrode-framework-enables.html More information: Hongtao Sun et al. Three-dimensional holey-graphene/niobia composite architectures for ultrahigh-rate energy storage, Science (2017). DOI: 10.1126/science.aam5852AbstractNanostructured materials have shown extraordinary promise for electrochemical energy storage but are usually limited to electrodes with rather low mass loading (~1 milligram per square centimeter) because of the increasing ion diffusion limitations in thicker electrodes. We report the design of a three-dimensional (3D) holey-graphene/niobia (Nb2O5) composite for ultrahigh-rate energy storage at practical levels of mass loading (>10 milligrams per square centimeter). The highly interconnected graphene network in the 3D architecture provides excellent electron transport properties, and its hierarchical porous structure facilitates rapid ion transport. By systematically tailoring the porosity in the holey graphene backbone, charge transport in the composite architecture is optimized to deliver high areal capacity and high-rate capability at high mass loading, which represents a critical step forward toward practical applications. In a perfect world, batteries would have unlimited energy storage delivered at speeds high enough to power devices with unlimited needs. The phaser from Star Trek, for example, would require far more power and speed than is possible in today’s devices. While it is unlikely that such technology will ever come about, it does appear possible that batteries of the future will perform much better than today, likely due to nanostructured materials—they have already shown promise when used as electrode material due to their unique properties. Unfortunately, their use has been limited thus far due to the ultrathin nature of the resulting electrodes and their extremely low mass loadings compared to those currently in use. In this new effort, the researchers report on a new way to create an electrode using graphene that overcomes such limitations.The electrode they built is porous, which in this case means that it has holes in it. Those holes, as Cheng and Li note, allow better charge transport while also offering improved capacity retention density. The graphene framework they built, they note, offers a superior means of electron transport and its porous nature allows for a high ion diffusion rate—the holes force the ions to take shortcuts, reducing diffusion.Cheng and Li suggest the new work is likely to inspire similar designs in the search for better electrode materials, which they further suggest appears likely to lead to new electrodes that are not only practical, but have high mass loadings. 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. New graphene framework bridges gap between traditional capacitors, batteries Explore further
In physics, the Marangoni effect describes differences in surface tension between liquids that can lead to seemingly strange behaviors such as “tears” forming in a glass of wine with a lot of alcohol in it. In this new effort, the researchers explored the Marangoni effect as it applies to the bouncing of oil drops in a jar containing a water/ethanol gradient.To set up the experiment, the researchers carefully poured ethanol into a jar of water, avoiding too much mixing, such that a density gradient formed naturally. Then, they introduced a single drop of oil, in this case, anethole, into the container. The drop sunk slowly through the mixture before rapidly rebounding straight back up. The drop does this several times before eventually sinking all the way to the bottom of the container. After careful study of the whole scenario, the researchers discovered what was actually happening.At the onset, the drop falls due to gravity—the researchers found that as it does so, the surface tension on the drop is different on the top and bottom (the Marangoni effect), resulting in an energy buildup. Once it reaches a tipping point, the energy is released, pushing the drop back up toward the surface. But each time it falls and rebounds, the amount of stress that builds up lessens, likely due to the mixing of the water and ethanol as the drop moves down and up repeatedly. Eventually, the amount of energy released is not sufficient to propel the drop upward, and it falls to the bottom of the container. The researchers note that the same scenario can be replicated using other types of oil and liquid density gradients. More information: Yanshen Li et al. Bouncing Oil Droplet in a Stratified Liquid and its Sudden Death, Physical Review Letters (2019). DOI: 10.1103/PhysRevLett.122.154502 . On Arxiv: https://arxiv.org/abs/1812.01498 Special surface manipulation forces dropped liquids to spiral when they rebound Citation: Why a drop of oil bounces in a water/ethanol gradient and eventually falls to the bottom of a jar (2019, May 1) retrieved 18 August 2019 from https://phys.org/news/2019-05-oil-waterethanol-gradient-eventually-falls.html
Kolkata: The Kolkata Municipal Corporation (KMC) on Tuesday completed the installation of the foot overbridge opposite Alipore Zoo.The estimated cost of the foot overbridge is Rs 4 crore and has been constructed on a Public-Private Partnership (PPP) model. The KMC’s partner is Karukrit. There will be an escalator and the civic authorities will take a few more months to make it operational. The work has been completed on record time. The Kolkata Police had halted traffic movement along Belvediere Road from Saturday night until Tuesday evening to facilitate the civic authorities to carry on with the work of installation. Also Read – Heavy rain hits traffic, flightsThe fabricated superstructure was brought and the civic engineers installed it on Tuesday morning ahead of the stipulated time.The foot overbridge is likely to ease the traffic movement near Alipore Zoo. During winters, when there is a heavy turnout of visitors at the zoo, sometimes it takes more than half an hour to reach Race Course from Zoo. Throughout the year, there is traffic congestion as besides cars, many Vidyasagar Setu bound trucks from South 24-Parganas enter the city through this route. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killed Besides, the zoo, there is a star hotel, the Alipore campus of Calcutta University and National Library. Also, this is the Chief Minister Mamata Banerjee’s route to Nabanna from her Kalighat residence. It may be mentioned that the Traffic department of Kolkata Police had suggested the KMC to construct foot overbridges at seven important intersections to ease traffic movement. But due to fund constraints, the KMC found it difficult to construct the bridges on its own and decided to construct it a on PPP model.The city police had suggested construction of a foot overbridge at Esplanade to facilitate pedestrians. It also suggested a foot overbridge at the Shyambazar five point crossing.
If you are ill and scheduled for a medical procedure, keep calm as feeling high levels of distress, fear and hostility prior to undergoing a surgery like angioplasty may lead to poor outcome, said a study.“I was surprised by this result. Prior to this study, I did not believe patient mood could have an effect on outcome,” said study author Nadja Kadom, acting associate professor of radiology at Emory University School of Medicine.The team analysed the results of 230 patients, including 120 women and 110 men (mean age 55 years) who underwent interventional radiology procedures including vascular and kidney interventions. Upon arriving for their procedure, patients were asked to complete a questionnaire called the Positive Affect Negative Affect Schedule (PANAS) to assess their mood. Also Read – ‘Playing Jojo was emotionally exhausting’Using a five-point rating scale, the patients reported to what extent they felt strong, alert, determined and other positive feeling states and to what degree they were experiencing negative feelings, such as guilt, nervousness or irritability. Dr Kadom and fellow researchers grouped the patients based on high and low scores for positive affect and high and low scores for negative affect.Those groups were then correlated with the occurrence of adverse events during the procedures, such as a prolonged lack of oxygen, low or high blood pressure, post-operative bleeding or an abnormally slow heart rate. The data revealed that patients with a high negative affect experienced significantly more adverse events than patients with low negative affect. Also Read – Leslie doing new comedy special with NetflixOf the 104 patients with high negative affect, 23 (22 per cent) had an adverse event, compared to 15 (12 per cent) of the 126 patients with low negative affect.“Our study shows that mood matters. You don’t need to have a chipper, cheery attitude prior to your procedure. You just have to overcome negative emotions and get to a neutral level,” noted Dr Elvira V Lang, interventional radiologist in Boston.The health care teams should be trained in resilience and techniques to create their own positive emotional states, as well as coping strategies to help patients modify negative emotions and reframe their mindset prior to undergoing a procedure, the authors noted.
Kolkata: Two persons were arrested for allegedly blackmailing a senior citizen from Salt Lake.Police found that a woman along with her son used to blackmail people and demand random amount from them. Both of them were arrested on Saturday. According to the complaint, one Girdhari Lal Singhal, a resident of GC block in Salt Lake received a phone call on his mobile phone on November 15 evening from one Soumyak Majumdar. But he rejected the call as he couldn’t identify any called Soumyak as it appeared on the Truecaller app. Also Read – Rain batters Kolkata, cripples normal lifeAgain on November 21 he got a call from the same number. When Singhal answered the call Soumyak handed over the phone to his mother Anjana. It was alleged that she ordered Singhal to meet Soumyak soon. She threatened Singhal with dire consequences if he did not abide by her instructions. Singhal immediately disconnected the call and put the number on the block list. Later, he received several calls from the same number — 8961920096 but got automatically rejected as it was on the block list. On November 22, he received some pictures of his wife from another mobile number on WhatsApp. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedSinghal alleged that Soumyak and Anjana managed to download pictures and get details of his family members from Facebook. The details included his daughter and two sons. In due course of time, several messages were sent to Singhal saying several girls would go to his home to malign his image and social status. The pictures of his wife and daughter would be circulated for the same intention. In the next step, the duo demanded Rs 2 lakh from Singhal and said they would discontinue to harass him if he agrees to pay. On November 23 evening, Singhal lodged a complaint with Bidhannagar South police station reagarding the matter. On receiving the complaint police asked Singhal to fix an appointment with Anjana pretending to give her the money demanded. Singhal was also asked to tell Anjana that he would bring a friend along with him. As Anjana did not suspect it to be a trap, she agreed. On Saturday evening, Anjana came to Vivekananda Yuba Bharati Krirangan area in Salt Lake to collect the money. Singhal was waiting with a police officer from Bidhannagar South police station who posed as his friend. Other police personnel including ladies were in plain cloth waiting for Anjana. After arriving she demanded Rs 5 lakh. But Singhal asked her to finish the matter with Rs 2 lakh to which she refused. In the meantime, police personnel surrounded them. Anjana was arrested and taken to the police station. Later, police called Soumyak through Anjana at night and arrested him. Both of them were produced before Bidhannagar court on Sunday and were remanded to 4-day police custody. It was found that Soumyak was previously arrested by Jadavpur police station for allegedly molesting a girl in the year 2013.
The ability to get inspired by your surroundings and to be able to see depth and beauty in everything is what true art is about. Thus, art has the power to transform, to illuminate, to educate, inspire and motivate. And it is only an artist who sees beauty that constitutes the romantic character in art. “Somewhere over the rainbow” by self taught artist Keerti Raj is one such exhibition that shows the beauty in the mundane. A pediatrician and mother of two, Keerti Raj says, “In youth being a doctor, a mother, a wife and then a house maker, time flew for me and created a vacuum in my life. The period of bringing up both my daughters had taken up all my time. But now the free time I had craved for then had started weighing heavily on my hands and mind. My growth as an artist has been possible only due to the constant encouragement and mentoring by Mr Jitendra Padam Jain, who has been my guiding light. I now feel and know a sense of purpose and direction in my life. Self-expression – which had been dormant for the better part of my life has finally found an outlet. My confidence grows with each new canvas and I have a new identity – an artist.” Also Read – Add new books to your shelfReferring to her work Keerti Raj says, “My world is a land of exquisite beauty, blazing warmth, vibrant nature and myriad hues. As you walk among the exhibits, different shades will immerse your senses and leave you gratified by the end. An artist is a receptacle of emotions that he/she has absorbed with the passage of time. Elements like the sky, the earth, living beings, a single scrap of paper, an ephemeral shape or the dance of waves contribute to accomplish the right balance. There are no fixed rules to follow. The artist’s horizon is limitless.” Also Read – Over 2 hours screen time daily will make your kids impulsive”Somewhere over over the Rainbow” is being presented by Gallery Sree Arts founder and Managing Director Jitendra Padam Jain from January 20 to 25 at India Habitat Centre in New Delhi. He is assisted by Annkush B Sharma. The exhibition will also see the inauguration of the annual calendar of Gallery Sree Arts showcasing the artworks of Keerti Raj.
Kolkata: Tension ran high at Jalpaiguri Superspecialty Hospital on Wednesday morning following the death of a woman whose family members have brought the charges of negligence against the hospital.The family members of the victim staged a demonstration inside the hospital campus accusing doctors of glaring medical negligence that have led to the death of the woman. A large contingent of police rushed to the spot to bring the situation under control with hospital authorities ordering a probe into the incident. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedJarina Khatun (30), a resident of Sardarpara area under Rajgunj block in the district, was admitted to the hospital on Tuesday morning with severe chest pain. On Wednesday morning, the family members of the victim were told that Khatun had died. As soon as the news spread, some of the family members and locals staged a protest demonstration alleging that the woman died due to the negligence. They also alleged that no treatment was provided to her. The incident triggered chaos in the area. Also Read – Bose & Gandhi: More similar than apart, says Sugata BoseThe victim’s family members demanded stern action against the responsible doctor. Had she been given proper treatment, the patient would have survived, her family members claimed. They later lodged a complaint with the hospital authorities and a probe has been initiated. The hospital authorities have assured the family that justice would be delivered. Locals alleged that patients visiting the Outdoor departments of the hospital are often kept waiting resulting in inconvenience. They also urged the hospital authorities to take steps in this regard.