Month: August 2019

Modified gravity v dark energy

center_img Supercomputer shows ‘Chameleon Theory’ could change how we think about gravity 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.last_img

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Polymer remembers four shapes

first_img © 2010 PhysOrg.com Researchers design shape-memory polymers for biomedical applications Explore further Quadruple-shape memory properties of PFSA. Visual demonstration. Image credit: Nature. More information: Tunable polymer multi-shape memory effect, Tao Xie, Nature, 464, 267-270 (11 March 2010), DOI:10.1038/nature08863 (PhysOrg.com) — A new study by General Motors has found that a polymer used commercially in fuel cell membranes can “memorize” four shapes, each assigned to a different temperature. The material could find applications in fields such as space exploration and biomedical engineering. Xie said that each shape would be assigned to a specific temperature chosen by the manufacturer. As long as there is sufficient difference between the temperatures, the material has been demonstrated to be able to hold four shapes, but Xie said it may be able to hold more. The next step in the research is to investigate shape memory polymers that are more appropriate for bulk processing, and those with UV radiation resistance for use in space, or biocompatibility for use in medical applications such as self-tying sutures, bone implants and blood vessel stents.The paper, by Tao Xie of the General Motors Research and Development Center in Warren, Michigan, is published in the journal Nature. The material, a perfluorosulphonic acid ionomer (PFSA) called Nafion, is a shape memory polymer. These materials can remember shapes set under specific conditions of moisture content, temperature, light, or exposure to a magnetic field. When they are next exposed to the same conditions, they revert to the remembered shape. Shape memory polymers have been known for decades, and have been used in wiring insulation and other industrial applications. Tests have been carried out for medical purposes such as stents for clearing blood vessels of clots, and the US space agency NASA has also considered using shape memory polymers for applications such as unfolding antennas in space. Previous polymers have only been able to remember two or three shapes including the original shape, and Nafion is the first known material that can memorize four.The research team, led by Tao Xie, heated thin films of Nafion, shaped it at a fixed temperature, and then cooled the material. They then repeated the process for other temperatures and shapes. When reheated the polymer reverted to the shape formed previously at that temperature. The shapes are locked in when the material is at its transition temperature, at which its structure changes from a frozen “glass” to a mobile “rubbery” phase. Nafion is able to hold more shapes than other polymers because it has a wide transition temperature range from about 55 to 130°C, leaving more temperature options available. Triple-shape memory properties of PFSA. a. Visual demonstration. b. Quantitative thermal mechanical cycle. Image credit: Nature. Citation: Polymer remembers four shapes (2010, March 15) retrieved 18 August 2019 from https://phys.org/news/2010-03-polymer.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.last_img read more

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Oldest known sponge found in China

center_img More information: Sponge grade body fossil with cellular resolution dating 60 Myr before the Cambrian, PNAS, Zongjun Yin, DOI: 10.1073/pnas.1414577112AbstractAn extraordinarily well preserved, 600-million-year (Myr)-old, three-dimensionally phosphatized fossil displaying multiple independent characters of modern adult sponges has been analyzed by SEM and synchrotron X-ray tomography. The fossilized animal (Eocyathispongia qiania gen. et sp. nov.) is slightly more than 1.2 mm wide and 1.1 mm tall, is composed of hundreds of thousands of cells, and has a gross structure consisting of three adjacent hollow tubes sharing a common base. The main tube is crowned with a large open funnel, and the others end in osculum-like openings to the exterior. The external surface is densely covered with flat tile-like cells closely resembling sponge pinacocytes, and this layer is punctuated with smaller pores. A dense patch of external structures that display the form of a lawn of sponge papillae has also survived. Within the main funnel, an area where features of the inner surface are preserved displays a regular pattern of uniform pits. Many of them are surrounded individually by distinct collars, mounted in a supporting reticulum. The possibility cannot be excluded that these pits are the remains of a field of choanocytes. The character set evinced by this specimen, ranging from general anatomy to cell type, uniquely indicates that this specimen is a fossil of probable poriferan affinity. So far, we have only this single specimen, and although its organized and complex cellular structure precludes any reasonable interpretation that its origin is abiogenic, confirmation that it is indeed a fossilized sponge will clearly require discovery of additional specimens. (Phys.org)—A team of researchers with members from China, the U.S. and France has identified an ancient sponge found in a geologic formation in southern China and have dated it to 600 million years ago. In their paper published in Proceedings of the National Academy of Sciences, the team claims the sponge is the oldest ever found and likely represents a group of descendants that is an ancestor of all sponges. Citation: Oldest known sponge found in China (2015, March 10) retrieved 18 August 2019 from https://phys.org/news/2015-03-oldest-sponge-china.html Journal information: Proceedings of the National Academy of Scienceslast_img read more

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Target luxury

first_imgWalter Knoll, a luxury German furniture brand, further strengthens its presence in India by announcing Alpana Kirloskar, renowned architect and interior designer, as its Brand Ambassador for the Indian Market. The announcement was made by Markus Benz, CEO and Partner, Walter Knoll on 28 September at Taj Mahal Hotel in the Capital. Kirloskar commented, ‘It is an honour to be associated with the brand and I relate to its 150 year old legacy and core values and beliefs. As an architect I respect the excellence for high quality, timeless design, skilled craftsmanship and attention to detail. I am proud to be the brand ambassador of Walter Knoll and strengthen its presence amongst the discerning Indians.’   Also Read – ‘Playing Jojo was emotionally exhausting’Markus Ben said, ‘India is a country with a modern understanding of architecture and design. Increasing wealth, the presence of international premium brands, and appreciation of quality and design, marks India as a growth market. We want to further strengthen the brand Walter Knoll in India.’Other guests present at the event were – Raseel Gujral, Mohit Gujral, Jyothi Rath, and Sunita Kohli, among others. Industrialists like Priya Paul, Nakuland Timsy Anand, Dipika Jindal, Alok Modi, Sushil Ansal, Sheetal Ansal, Sanjay Chandra, Archana and Vipin Luthra were also present.last_img read more

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South Bengal districts parts of city receive moderate rain

first_imgKolkata: Rains, along with squally winds, lashed some of the South Bengal districts of Bengal and the northern fringes of the city on Sunday afternoon, creating inconvenience for people. Slow traffic movement was reported in some parts, including suburban areas, following the rain. The districts that have received the maximum rainfall, are North 24-Parganas, South 24-Parganas, Howrah and Hooghly. Some other districts have also received rainfall. Rain was moderate in the northern parts of the city and its outskirts. Also Read – Heavy rain hits traffic, flightsThe regional meteorological centre has predicted that a wind measuring around 50-60 km per hour may sweep through some of the South Bengal districts, along with moderate rainfall in the next 24 hours. Various parts of the city and the districts remained overcast from Sunday morning. According to the weather office, a low pressure trough has formed, bringing rainfall in the city. Sunday’s rainfall has brought down the temperature in the city and its adjoining areas by a few notches. This has given relief to the people, who were facing sultry and uncomfortable weather for the past couple of days. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedIt may be mentioned that an alert has been issued to East Midnapore district administration, saying that there may be a high tide in Digha. The fishermen in the area have been alerted not to venture out, due to rough sea. A thunderstorm, along with rainfall, had lashed the city on last Tuesday, killing 18 persons across the state.The meteorological office in Alipore predicted that similar conditions may prevail for the next 24 hours. Apart from the city, the coastal districts will also receive light to moderate rainfall, along with a strong wind which will also sweep through South Bengal. The sky will remain cloudy in some parts of the state.last_img read more

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Kate Moss husband to exhibit her nude photos

first_imgSupermodel Kate Moss’ husband Jamie Hince is planning an exhibition of his wife’s naked photographs. His debut exhibition opened last June in New York.The model is thought to be excited about becoming the centre of attention in the display.“Jamie is compiling a series of iconic nude photographs of his wife around their home for his second exhibition,” a source told dailystar.co.uk.last_img

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AAP MLAs demand gazetted holiday on Ambedkar Jayanti

first_imgAAP’s Kondli MLA Manoj Kumar said that Ambedkar Jayanti falls under restricted holidays, as announced by the government. However, former Delhi Minister Raj Kumar Chauhan had said that Ambedkar’s birth anniversary has always been celebrated as a holiday. The government of India has maintained Ambedkar’s Jayanti under the observance holiday category, while Vaisakhi has been kept as restricted holiday on same date. Kumar said that every year, the city government announces a holiday on this day, around 10-12 days before the jayanti. “We met the CM and demanded him to announce a holiday for Ambedkar’s birth anniversary,” Kumar said.last_img read more

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Aroop Biswas to hold meeting today to end Tollywood tussle

first_imgKolkata: The stalemate in the shooting of television serials in Tollywood may be resolved, as the state Youth affairs minister Aroop Biswas will convene a high level meeting with the representatives of Artistes’ Forum and Federation of Cine Technicians on Thursday.It is assumed that the technicians may arrive at a negotiation with the producers. There had been a ceasework by the Artistes’ Forum, with a demand to regularise pay.The producers’ association said it was ready for talks with no pre-condition, while the artistes body maintained that dialogue would start only after getting a formal letter from the other side. Also Read – Rain batters Kolkata, cripples normal lifeThe talks between the forum and the Welfare Association of Television Producers (WATP) had yielded no results. Federation of Cine Technicians and Workers of Eastern India had issued a Press release on Tuesday, saying that the artistes have agreed to join work the moment WATP agrees to implement the MoU signed between the producers and artistes.The forum had also specified that any artiste working for more than 10 hours should be paid on an hourly basis, after the expiry of the scheduled time. But the decision had not been honoured by a section of producers. The minister will hold the meeting so that a solution can be arrived at.It may be mentioned that the stand-off between theTollywood artistes andproducers has entered its fifth day on Thursday. Due to the resulting disruption of the shooting schedule, thechannels were forced to go for repeat telecast of the episodes aired earlier.last_img read more

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