(Left) A cryostat containing the superconducting solenoid magnet used for magnetic levitation experiments. The solenoid is kept at a temperature of 4 Kelvin (-269 Celsius). (Right) Cross-section diagram showing the water droplet levitating inside the bore in the magnet, and the positions of the electrodes used to apply the current used to spin the droplet. Image credit: Hill and Eaves. “Firstly, for us, it’s interesting to observe water – familiar to everyone – in unusual circumstances: here we have a water droplet floating weightless on Earth, and we spin it by passing an electric current through it, effectively turning the droplet into an electric motor,” Hill told PhysOrg.com. “We’re excited about these results because the behavior of a 1-cm-diameter spinning weightless droplet, an object on the ‘human’ scale, can give insights into objects at nuclear length scales and also at astronomical sizes. We hope that by studying a spinning weightless water droplet, something easily observable with the naked eye, we may help other researchers trying to understand much stranger objects such as black holes and atomic nuclei.”Scientists have been intrigued with spinning water droplets going back to 1863, when the Belgian physicist Joseph-Antoine-Ferdinand Plateau suspended a drop of olive oil in a water-alcohol mixture of the same density. He used a rotating shaft to spin the oil droplet and found that the droplet changed shape: it became flattened at the poles, and bulged at the equator (which, incidentally, is similar to the shape of the Earth due to its rotation). More recently, theoretical investigations have revealed that a droplet’s shape should change depending on its rotational velocity, assuming a series of shapes as it spins faster and faster. The reason for this distortion, the scientists explain, is that a droplet seeks the lowest energy state for a given rotational frequency. Specifically, it begins as a sphere when at rest, and then progresses into a two-lobed “peanut” shape.Theory predicts triangular (three-lobed) and square (four-lobed) shapes at higher rotational velocity, but these shapes should be unstable and should decay into the ellipsoid shape. Yet previous experiments on acoustically levitated droplets have shown that it’s possible to stabilize a spinning triangular shape. However, in these experiments, the droplet’s shape oscillates strongly as it spins, so the equilibrium shape is not clearly observed in these demonstrations. Explore further A spinning and levitating 1.5ml water droplet, shown forming a 3-lobed, triangular equilibrium shape. The nine consecutive movie frames are taken 1/50 second apart. Image credit: Hill and Eaves. Researchers Richard Hill and Laurence Eaves of the University of Nottingham in the UK have recently designed an experiment that exploits the possibilities of a spinning water droplet to the fullest. Their technique overcomes previous challenges, such as completely removing the effects of gravity, and minimizing the viscous drag caused by spinning in order to stabilize the droplet. Their study is published in the December 5th issue of Physical Review Letters. Citation: Spinning Water Droplets Could Provide Insights into Black Holes, Atomic Nuclei (2008, December 15) retrieved 18 August 2019 from https://phys.org/news/2008-12-droplets-insights-black-holes-atomic.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. How plague pathogens trick the immune system By magnetically levitating water droplets, and using a “liquid electric motor” technique to spin them, researchers can investigate how the droplets change shape. Rather than being just a curious experiment, the results could provide insights into systems that cannot be controlled in the laboratory, such as black holes and atomic nuclei. In the current study, Hill and Eaves used techniques that, for the first time, allowed them to see the equilibrium three-lobed shape clearly. To do this, they first found an innovative way to create a gravity-free environment, by using diamagnetic levitation. Because water is diamagnetic, the electrons in the water molecules rearrange themselves in the presence of an applied magnetic field, creating small currents. These currents oppose the applied magnetic field by Lenz’s Law, and generate a strong enough magnetic repulsion to balance the force of gravity, so that the droplet levitates. Once the droplet is weightless, the researchers used a novel “liquid electric motor” technique to spin the droplet. They inserted two thin wire electrodes in the droplet, and passed a current through the wires, creating a torque on the droplet that causes it to rotate. By adjusting the current, the researchers could easily control the frequency. More importantly, the flow of water past one of the electrodes sets up small waves on the surface of the droplet, and these side currents can help stabilize the droplet, preventing the many-sided shapes from decaying into an ellipsoid. The researchers found that the behavior of the peanut and triangular shapes agreed well with theoretical predictions.The researchers hope that understanding spinning water droplets could provide insights into other systems that have analogies with fluids. For instance, gravity and the strong nuclear force behave in a similar way to surface tension in that they are all cohesive forces. Understanding the surface tension in a spinning water droplet, then, could help scientists understand how astronomical bodies, as well as atomic nuclei, are held together.“Cosmologists believe that the event horizon of a black hole behaves as if it possesses surface tension, like a droplet,” Hill explained. “The stability of the shapes of a spinning droplet could tell us some new things about the stability of the event horizon of a spinning black hole.“The shapes of other more familiar astronomical objects such as planets and asteroids, which are held together by their own gravity, rather than by surface tension, also follow a similar pattern to that of the droplet,” he continued. “For example, recent observations of asteroids in the Kuiper belt beyond Neptune have revealed objects with an ellipsoidal shape, probably due to their rapid spin, similar to that observed in our experiments.”The scientists added that, in the liquid drop model of the atomic nucleus, recent work has been done investigating the stability of very rapidly spinning atomic nuclei. Researchers can use the behavior of a liquid droplet to gain insights into this problem, as well.In the future, the scientists plan to further investigate the possibilities of magnetic levitation.”We’re investigating whether magnetic levitation can be used to explore what happens to biological organisms, such as plants, in a weightless environment like that of space,” Hill said. “We can keep objects levitating for months using our magnet – the information we get from long-term experiments could be extremely useful for future missions to the Moon or Mars. However, like Plateau, studying floating oil droplets in 1863, we may have to wait several decades before this work finds applications!”Watch videos of the spinning water droplet as it changes shape at netserver.aip.org/cgi-bin/epap … =E-PRLTAO-101-065848 (Supplementary movies.zip).More information: Hill, R.J.A. and Eaves, L. “Nonaxisymmetric Shapes of a Magnetically Levitated and Spinning Water Droplet.” Physical Review Letters 101, 234501 (2008).Cardoso V. “The many shapes of spinning drops.” Physics 1, 38 (2008) physics.aps.org/articles/v1/38 Copyright 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.
One of the first reaction mechanisms students learn in undergraduate organic chemistry is the SN2 reaction. Named because it involves the collision of two molecules, its energy barrier is related to the nucleophile, the solvent, and the leaving group. Exactly how the leaving group influences what is going on at the molecular level, however, remains elusive. © 2015 Phys.org Study reveals peculiar mechanism of radical addition-elimination Using reaction cross-beam scattering and velocity map imaging combined with simulation studies a gas-phase SN2 reaction, F- + CH3Cl-, and comparing it to prior studies of F- + CH3I, Martin Stei, Eduardo Carrascosa, Martin A. Kainz, Aditya H. Kelkar, Jennifer Meyer, Istvan Szabo, Gabor Czako, and Roland Wester from the Institute for Ion Physics and Applied Physics, Universitat Innsbruck in Austria, the Institute of Chemistry, Eotvos University in Hungary, and the University of Szeged in Hungary have determined that the leaving group has a strong influence on reaction dynamics by influencing the orientation of the reactants. Specifically, they found that while both the chlorine and iodine reactions form a hydrogen bonding complex at the entrance channel, key differences cause one to be a direct rebound mechanism while the other is an indirect mechanism. Their work is reported in Nature Chemistry.Reaction dynamics is the study of individual molecular collisions. While kinetic theory describes a mechanism based on aggregate behavior, reaction dynamics looks at individual particles. Reaction dynamics answers questions such as “Do the reactants need to collide in a certain way in order for a reaction to occur?” To answer questions about particular collisions, reaction dynamics studies must be conducted in the gas phase. This particular study looked at collisions using ion beams to control reactant velocity and TOF-MS to measure product velocity. In the SN2 reaction F- + CH3Cl- à CH3F + Cl-, fluorine serves as the nucleophile, which engages in a “nucleophilic attack” on CH3Cl, and chlorine serves as the leaving group. This reaction occurs through an orchestrated process that, on the molecular level, shows that fluorine must collide directly with the electrophilic carbon, rather than the chlorine or hydrogens. Lower velocities did indicate an indirect complex-mediated mechanism, but for most velocities, this reaction undergoes a direct rebound mechanism. This is evidenced from scattering data that shows the chlorine leaving scattering in the backward direction. Lower velocities showed isotropic scattering. Even though there is evidence of a hydrogen bonding complex at the entrance channel, this reaction is not a slow, complex-dependent mechanism. The hydrogen complex, however, may affect reactant orientation. This is not the case for the analogous reaction with iodine as a leaving group: F- + CH3I- à CH3F + I-. Prior studies showed that while this reaction does display some backscattering, it seems to have a greater isotropic distribution and higher internal energy at most velocities, indicating an indirect complex-mediated mechanism. For this reaction, the collinear entrance channel plays a more important role in lowering the reaction energy barrier than forming a hydrogen complex. In other words, the reactants may impact each other in various ways.Simulation studies confirmed the experimental results of the chlorine reaction. Additional simulation studies showed that mass differences do not play a role in the differences between these reactions mechanisms, and impact parameter measurements indicate that reactant orientation is much more efficient in the case of the chlorine reaction compared to the iodine reaction. This is likely due to CH3Cl having a larger dipole moment compared to CH3I, which causes the fluorine ion to preferentially impact CH3Cl in a direct rebound orientation.This study shows that given by comparing seemingly analogous gas-phase SN2 reactions, at the molecular level, their reaction dynamics are distinctly different. These differences are due to properties of the leaving group that are beyond differences in mass, and likely have to do with molecular orientation upon impact. Journal information: Nature Chemistry Citation: Study clarifies the role of the leaving group in gas-phase bimolecular reaction (2015, December 18) retrieved 18 August 2019 from https://phys.org/news/2015-12-role-group-gas-phase-bimolecular-reaction.html Explore further More information: Martin Stei et al, Influence of the leaving group on the dynamics of a gas-phase SN2 reaction, Nature Chemistry (2015). DOI: 10.1038/NCHEM.2400 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.
If you’re like me, even the simplest decisions can make your pulse race. And when it comes to big, life-altering choices, the need to get it right (because life is short!), combined with ever-looming F.O.B.O. (fear of better options), can cause a state of near paralysis. Should you order tacos or tikka masala? Stay at the hotel with the free breakfast or the one with all the succulents? Melt into the couch or drag yourself to happy hour? While this abundance of choice is a result of incredible privilege — not everyone has the freedom to select where they work or live, or how to spend their time or money — it can still be overwhelming. As Barry Schwartz, the author of “The Paradox of Choice,” said, “I’m reasonably confident we’re operating with far, far more options in most parts of our life than we need and that serve us.” Here are five strategies for spending less time agonizing over decisions and more time appreciating the results: Read the whole story: The New York Times
‘Of course I want to settle down with someone once again. Why wouldn’t I? You see, all these years I’ve single-mindedly focussed on my sons Azaan and Zahaan. Their well-being and happiness are all that mattered to me while they were growing up. ‘Now that they have matured and have a life of their own. I can begin to think about my own life once again,’ says Zeenat.Initially, Zeenat worked round the clock to become one of the most sought-after actresses in the 1970s. Her marriage to Mazhar Khan in 1985 considerably slackened her work-pace. ‘I hold no grudges against anyone. I believe there are good people out there. And I believe there is always room for love and companionship,’ she added.
In the painting, Kendra Within, the birds, represent thoughts, white symbolises good thoughts, black evil and blue, which dominates the centre, stands for enlightenment.It seeks to emphasise that great destinations are found within, at the centre of the self and that this eternal inner destination can be accessed through yoga.An ongoing exhibition, Yoga Chakra-Tradition and Modernity at Sangeet Natak Akademi, seeks to go beyond the conventional belief of yoga being a solely physical exercise and focus on it as something that is “good for mind body and soul.” Also Read – ‘Playing Jojo was emotionally exhausting'”People, today, are talking about yoga as a kind of physical exercise, which it is, but in addition to that the synergy between mind and body is very important,” said Sushma Bahl, the curator of the exhibition.”To establish this synergy, we have juxtaposed classical and historic art pieces against very contemporary ones,” she added.It was inaugurated last evening by the Culture Minister Mahesh Sharma. “The fact that the International Yoga Day was celebrated across the world today is a matter of great pride for India. Yoga is a part of our culture and our ancient culture has found a place worldwide with the celebration of Yoga Day today,” said the minister. Also Read – Leslie doing new comedy special with NetflixComprising of about 389 artworks by 150
Kolkata: A civic volunteer was arrested on Sunday for allegedly beating his mother to death in West Bengal’s Hoogly district, police said. “Rabin Kundu, a resident of Hoogly district’s Arambag was arrested for allegedly beating his septuagenarian mother to death today morning. He will be produced before the court tomorrow (Monday),” an officer from Arambag Police Station said. Kundu allegedly attacked his mother with a wooden stick after the woman had an altercation with one of their relatives, police said. Also Read – Rain batters Kolkata, cripples normal life According to eye witnesses, Kundu’s mother had a verbal spat with his aunt over some family issues, which irritated the youth. After his aunt left, he attacked his mother with a stick, beating her repeatedly and the old woman became senseless, a neighbour said. The injured woman was then taken to Arambag sub-divisional hospital where she was declared brought dead. “It was a shocking incident. We handed him over to the police,” the neighbour said.
Musical notes resonated at the India Habitat Centre when the IHC ‘Morning Ragas’ concert was held on Sunday. The soulful morning was a lovely musical journey towards Uttarayan which is to be held in January. The artist for the morning concert was Kalapini Komkali, daughter and disciple of legendary Pandit Kumar Gandharva.She opened her recital with Raga Bilaskhani Todi in which she presented three compositions, the last being Pt Kumar Gandharva’s composition. Also Read – ‘Playing Jojo was emotionally exhausting’Next she presented the rarely heard Shukla Bilawal in which she sang two compositions before moving on to the more popular Alhaiya Bilawal. Kalapini’s next presentation was a Meera bhajan in her inimitable style. She ended the morning recital with a Kabir doha in Raga Bhairavi with the trademark Kumar Gandharva genre of singing. She was accompanied on the tabla by the young Ramendra Singh Solanki and on the Harmonium by Vinay Mishra.
During the final arguments in 2G spectrum allocation case, special public prosecutor Anand Grover said that Raja had not evolved any procedure, which was to be followed while dealing with pending applications for dual technology, despite the Telecom Regulatory Authority of India (TRAI) and Telecom Commission insisting on it.“No procedure was evolved to allocate dual technology licence. A Raja subverted the procedures. Everybody else was saying that evolve a procedure, but Raja deliberately ignored them,” Grover told Special CBI Judge OP Saini. Also Read – Punjab on alert after release of excess water from Bhakra dam“Without evolving any procedure, Raja gave approval to grant dual technology,” he said, asking that “a minister can approve it, but where was the procedure”.He further argued that “the entire process has to be fair. It was the government, so the process must be fair. There was no public announcement about it. Raja approved it arbitrarily to favour certain applicants.” Grover said that STPL was “ultimately favoured” in the entire process.“No procedure was evolved by the Department of Telecommunications (DoT). Everybody, from TRAI to Telecom Commission, was saying that a procedure should be evolved. There was no public announcement,” he said. “Without making it public, you are parting with the property of the state. This was done to favour certain people,” he said during the arguments, which would continue on Tuesday. Also Read – Union Min doubts ‘vote count’ in Bareilly, seeks probeIn its charge-sheet, the agency has alleged that Tata Tele Services Ltd and Spice Communications, which were having priority over STPL in terms of the dual technology approvals, were “unreasonably deprived” of the allocation of spectrum for Delhi circle.Raja, STPL and its promoters Shahid Usman Balwa and Vinod Goenka and 13 others are facing trial in the case. Raja and other co-accused have denied the allegations levelled against them by the CBI. Besides Raja, Balwa and Goenka, DMK MP Kanimozhi, former Telecom Secretary Siddharth Behura, Raja’s erstwhile private secretary RK Chandolia, Unitech Ltd MD Sanjay Chandra and three top executives of Reliance ADAG – Gautam Doshi, Surendra Pipara and Hari Nair – are facing trial in the case.Directors of Kusegaon Fruits and Vegetables Pvt Ltd Asif Balwa and Rajiv Agarwal, Kalaignar TV Director Sharad Kumar and Bollywood producer Karim Morani are also accused in the case, besides three telecom companies –Reliance Telecom Ltd, STPL and Unitech Wireless (Tamil Nadu) Ltd.In its charge sheet, CBI had alleged a loss of Rs 30,984 crore to the exchequer in allocation of 122 licences for 2G spectrum, which was scrapped by the Supreme Court on February 2, 2012. All the accused have denied the allegations levelled against them by the probe agency.
Kolkata: Following the incident of misbehaviour by an app-cab driver on Saturday, another app-cab driver has been detained by the Baguiati police station on Sunday night for misbehaving with a girl and her friends.However, police did not arrest the driver as no FIR was filed. Only a general diary was recorded but the driver has been prosecuted accordingly.According to the complainant, she, along with three of her friends booked an app-cab from Mukundapur. Their destination was Madhyamgram. Following the arrival of the cab, all four of them sat inside the car. As per the system, the driver was given the OTP to start the trip. Also Read – Rain batters Kolkata, cripples normal lifeHowever, seeing the destination on the app, the driver instantly refused to go. According to the complainant, during conversation the driver became agitated and denied to start the trip, saying: “my quota of trips has completed. I will not go.” On asking why he did not turn off his device as his trip quota completed, he became furious and started misbehaving.Later he told his passengers that he would drop them at airport gate number 1. He also advised the girl to book another cab from there. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedHearing the plan, the girl told him that if the total fare till Madhyamgram becomes same as per the booking, then they will pay him the fare up to airport. Otherwise the extra amount would be deducted from his quota. But the driver refused to accept.After this, all of a sudden the driver stopped the car beside the Eastern Metropolitan Bypass and allegedly forced all of them to get out of the car.Seeing no other way, the girl approached a traffic sergeant nearby for help. “When the sergeant arrived, driver still rigidly kept saying the same words. Following the intervention by police, the driver unwillingly agreed to take us. But the situation turned the same after a few moments.”While driving, the driver allegedly uttered some teasing words pointed towards us,” said the girl. Though all of them protested, he did not stop. Later, he even started using abusive language.Near Dum Dum Park on VIP Road, the girl called the police and asked for help.Near Baguiati, the cab was intercepted by the traffic police and the driver was laterhanded over to Baguiati police station.
The menu, available from Monday to Saturday, has an extensive variety of dishes available for each palate as fresh ingredients adds to its charm.As the summer heat has its most disastrous effect on one’s appetite, salads become an absolute necessity and one’s sheer delight. The Summer Special has a wide range of salads for both vegetarians and non-vegetarians. The ‘California Salad’, being referred to as ‘Californication’ by Chef Abhishek Singh, brings California to the plate. All the ingredients, including chicken, strawberry, pineapple and others, are imported from California. The freshness of the ingredients and the juiciness of the fruits topped with some basic spices is quite energizing. Also Read – ‘Playing Jojo was emotionally exhausting’‘The Duck Liver salad’ would be a treat for non-vegetarians. The creamy and earthy texture of the duck liver along with the sweet and crunchy apples create a blast of flavours. One of the most striking salads in the menu is the ‘Balsamic marinated vegetables’. Despite its simple taste, its presentation is elegant, as the rolled up zucchini dressed in balsamic vinegar, is beautiful to look at. The most prominent addition to the lavish buffet is the ‘ham and Cheese’ counter where all the required items are laid out for gourmets to attack on. With all the ingredients at bay, one could prepare the dish according to their personal taste and flavour requirement. Also Read – Leslie doing new comedy special with NetflixThe menu has the three most famous tikkas, namely ‘Paneer tikka’, ‘Chicken tikka’ and ‘Fish tikka’. While the ‘Paneer tikka’ felt soft and had apt spices, the ‘Chicken tikka’ was roasted to perfection. Only the ‘fish tikka’ could have been better had it been lightly roasted. The most exciting part of a meal comes at last. Rightly said, last but not the least, desserts are everyone’s dream. The Hyatt Café Summer Special had all sorts of desserts from Indian sweets like Gulab Jamun and Rasgulla to ‘Apple berry tart’ and Chocolate and mango swiss rolls. The Gulab Jamun would melt in the mouth, with the first bite allowing a burst of the right amount of sweetness. The ‘Banana Split’ had vanilla and butterscotch ice cream on top of the banana pieces. While the ice creams felt heavenly, the banana felt a little sour.The Summer Special menu is truly special as its comprehensive incorporation of various salads fulfills the job of letting one forget the heat outside and enjoy the coolness that meets the mouth.