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Physicists Investigate Controversy over RoomTemperature Ice

first_img Citation: Physicists Investigate Controversy over Room-Temperature Ice (2008, August 5) retrieved 18 August 2019 from https://phys.org/news/2008-08-physicists-controversy-room-temperature-ice.html (PhysOrg.com) — By confining water in nano-sized spaces, physicists from Leiden University in the Netherlands have turned water into ice at room temperature. While it’s not the first time scientists have created room-temperature ice, Dutch physicists K. B. Jinesh and Joost Frenken hope that their findings will put the controversial subject of water under nanoscale confinement in a new light. Explore further “The ice that forms in the confinement is normal ice; most probably, ice with a hexagonal lattice, which is the form of the most common crystalline ice seen in nature,” Jinesh said. The physicists also observed a few other ice formation traits. They found that, at higher humidities, ice appeared only to form under lower tip-scanning speeds compared to at lower humidities. This difference may be because high humidity causes the water film to be thicker, so that the molecules require more time for ordering, and need to be confined under the tip for a longer time.The researchers also observed evidence for static friction between the tip and the substrate, due to the ice formation. When the tip briefly paused, the ice had more time to become completely ordered, which made the tip “stick” more at that point in its stick-slip motion. “It is difficult to foresee an application at this level of invention,” Jinesh said. “The foreseeable difficulty is that in MEMS and NEMS, where the contact areas are shrinking in dimensions, ice formation could be a big problem that causes immediate failure of the devices. On the other hand, to increase friction wherever necessary, this technique could be employed, but it is so far a fiction, I would say!”More information: Jinesh, K.B. and Frenken, J.W.M. “Experimental Evidence for Ice Formation at Room Temperature.” Physical Review Letters 101, 036101 (2008).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 This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. 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. Compared with other liquids, water behaves in strange ways. When under extreme confinement – such as when squeezed between two surfaces in an area of less than 10 molecular diameters (or 1 nm) – most liquid molecules become highly ordered, acquiring a solid-like structure. But in the case of water, several factors theoretically oppose the molecular ordering under confinement. For one thing, water is the only liquid that expands when it freezes, making it difficult for water to turn into ice when confined to a small space. Some physicists have proposed that water’s unique characteristics cause it to remain a liquid under confinement, while others argue that water solidifies under confinement, with each water molecule sharing hydrogen bonds with its neighbors. “Some simulations and even experiments have shown that water retains its liquid state and bulk viscosity even under extreme confinement, down to 0.1 nm,” Jinesh told PhysOrg.com. “At the same time, some other experiments have shown that the viscosity of water changes under confinement. This experimental controversy is the difficulty existing in literature to explain how water would behave as a lubricant under various situations.”In their recent study published in Physical Review Letters, Jinesh and Frenken have demonstrated direct experimental evidence for water transforming into ice at room temperature when confined between two objects. By scanning the tungsten tip of a high-res friction force microscope over a graphite surface, the physicists showed that the water trapped in between due to capillary condensation rapidly transforms into ice due to confinement. The current study builds on the team’s initial demonstration of ice formation under confinement in 2006, but with more solid information about the structure of the ice formed. “Our experiment undoubtedly demonstrates that water crystallizes at room temperature, under confinement,” Jinesh said. “This is a strong step towards resolving the existing controversy of whether or not water would change its bulk property due to confinement.”Here, the physicists investigated how scanning speeds and changes in relative humidity affected the tungsten tip’s scanning motion, as measured by a friction-sensitive Tribolever cantilever on the tip. At low scanning speeds and modest humidity, the tungsten tip exhibited stick-slip motion, alternately stopping and sliding. The physicists explained that this motion occurs because of the subsequent breaking and resolidification of the ice that is firmly attached to the tip and to the graphite. Only the molecules between the tip and graphite are solid ice, while everywhere else the molecules remain in a liquid water state. Dust storms swirl at the north pole of Marslast_img read more

KMC to charge money from owners for not cleaning garbage

first_imgKolkata: The Kolkata Municipal Corporation (KMC) will charge money from owners of private houses, bodies of housing complexes and authorities looking after government properties for not cleaning garbage from their premises.This was decided at a high-level meeting held in the office of Borough XI on Wednesday.Representatives of Boroughs X and XII also attended the meeting. Atin Ghosh, Mayor-in-Council (Health), KMC Commissioner, Director Generals of building, solid waste management also attended the meeting. The Councilors of the Wards under the Boroughs were also present. Also Read – Rain batters Kolkata, cripples normal lifeA similar meeting will be held on September 22 in the office of Borough XIV. The senior officials of Boroughs XIII, XIV, XV and XVI will attend the meeting.The meetings are being held as a part of the drives against dengue.It was decided that the KMC will issue notices under Section 496A of the KMC Act to the owners who fail to clear garbage from their premises. The workers of the solid waste management department of the KMC will clear garbage from the premises and in the case of individual houses, the charges will be added to the property tax. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedIn case of government properties, the KMC will send the bill to the authorities looking after the buildings.In case the owners fail to pay the money, the KMC will file cases against them in the MunicipalCourt.In case of individual buildingswhere the civic authorities will fail to spot the owners or that are kept under lock and key for years together, the civic authorities in presence of local police will break open the lock and clean the premises. Senior KMC officials said that unless the individual house owners, authorities and bodies looking after the government buildings and housing complexes clean garbage from the premises, it is impossible for KMC to clean garbage from each and every premise which is the responsibility of the owners.They further added that to make the anti-dengue drive successful, cooperation from the owners of houses and authorities of institutional buildings is required.It may be mentioned that the civic authorities are engaging the Durga Puja committees to create awareness against dengue in their respective areas and the best Puja committee will be given cash award.”It is a collective drive and we seek cooperation from people representing all walks of life,” said Atin Ghosh, member, Mayor-in-Council (Health).last_img read more

Return of priceless artefacts

first_imgMarking the safe return of three stone sculptures from Australia to India, National Museum, Janpath has organised an exhibition titled, “Return of the Three Stone Sculptures from Australia to India.” The sculptures of Seated Buddha; Worshippers of Buddha; and Goddess Pratyangira were purchased by National Gallery of Australia from the Nancy Wiener, New York in 2007 and Art of the Past, New York, 2005. Minister of State for Culture and Tourism, Dr Mahesh Sharma inaugurated the exhibition on May 23. He attended a special event at National Gallery of Australia (NGA) in Canberra, Australia in which Senator Mitch Fifield formally handed over three ancient artefacts stolen and smuggled out of India and inadvertently acquired by National Gallery of Australia. Earlier, during the visit of Australian Prime Minister to India in September, 2014, the Australian government had also returned sculpture of ‘Dancing Shiva’. This exhibition is important as it celebrates the return of rare heritage sculptures that were stolen from the country. Also Read – Add new books to your shelfThe statue of worshippers of the Buddha: The panel depicts the worship of some of the Buddhist symbol (possibly chakrastambha or Bodhi tree but it is not visible as the piece is damaged at the top) kept on a throne, below which the Buddha-pada are visible. On both the sides, male worshippers are represented first followed by the female worshippers. The most probable offering objects held in their hands are vases with flower or garlands. This sculpture was unearthed in 1970s during the excavation of a Buddhist stupa at Chandavaram (District, Prakasham) in Andhra Pradesh. Also Read – Over 2 hours screen time daily will make your kids impulsiveSeated Buddha with large halo: (Kushan, 2nd century CE, Maholi, Mathura, Uttar Pradesh Spotted Red sand stone). This sculpture represents the Buddha seated cross legged (Padmasana) wearing ekansika sanghati (drapery covering one shoulder and arrayed with additional pleats). The transparent effect of the cloth is apparent through the conspicuous marking of the navel. The sculpture indicates that the right hand was raised in the abhaya mudra (protection pose) and the left rests on the thigh. He is shown with an urna, pralamba karna (elongated ear-lobes), ushnisha and with a filing contemplation on his face.Standing Pratyangira: (Chola, 13th Century CE, Tamil Nadu, South India Grey coloured granite stone). In order to carry out his supreme task of preservation, Lord Vishnu took incarnation in the form of Narasimha in which he is represented by a human body and a lion’s head, who destroyed the demon kind Hiranykashipu, the personification of evil. The deity represented here is a tantric deity who is the female aspect of God Narasimha also known as Narasimhi. She is standing in pralambapadita pose, the face of a roaring and furious lion while the body is of a female. Flames are coming out of her head. However, the attributes tridents (trisula) and drum (damaru) in her right hands suggest her to be Pratyangira, a form of Bhairavi as per Saivite cult. The image was under worship in Vriddhachalam temple near Chennai before its theft.last_img read more

Google Updates an App That Allows You to Search With the Swipe

first_img Google has rolled out an update to a mobile app that you might have never heard of but might find surprisingly useful. An app called Gesture Search can now understand swiped queries in more than 40 languages, Google announced over Google+ this week. For those of us who aren’t familiar with Gesture Search, the free app allows users of Android devices to simply draw a letter or number on the screen with the tip of a finger to access contacts, apps, music, documents and whatever else they might have stored on their Android-powered device. For instance, if you swipe the letter C, search results can turn up apps on your device such as the camera, clock of the Google Chrome browser.Gesture Search can be an alternative to the sometimes laborious task of typing on a small screen and can be far less disruptive to others than using voice control.Related: A Look at Google’s 200 Search Ranking Factors (Infographic)The app tailors itself to individual users based on their previous searches. It refines its results with each gesture the user makes. The updated app also supports transliteration, allowing users to write the way a word in another language sounds with their own alphabet.One drawback: Gesture Search only allows users to enter the first character in a search, forcing users to revert to a more traditional scrolling approach after their initial swipe.Many Android devices come preloaded with another gestural keyboard app called Swype, which allows users to compose messages in the same manner. For iOS users, there is a similar app free app called TouchPal, which also allows users to swipe their finger to compose messages instead of typing them out.This is the first significant update to Gesture Search since it was introduced as an experimental Google Labs project in 2010. Only available in the U.S., this update could foreshadow the app’s availability to a wider user base abroad.Related: Apple’s iOS 7 Includes New Design, Improved Usability   Growing a business sometimes requires thinking outside the box. Opinions expressed by Entrepreneur contributors are their own. June 13, 2013 Register Now » Free Webinar | Sept. 9: The Entrepreneur’s Playbook for Going Global 2 min readlast_img read more