first_imgThe Michigan team compared how the self-cleaning property would perform on a lotus leaf with both micro- and nano-structures or with only micro-structures to a lotus leaf. They also compared water drops on a piece of waxed cast smooth on glass. The scientists annealed (a process of heating and slow cooling) a sample of the leaves to melt the nano-scale hair structure while retaining the wax composition without chemical change. The team measured a significantly lower contact angle for the leaf with only micro-structures (126 degrees) and even lower for the smooth wax (74 degrees), compared with the contact angle of the two-structured leaf (142 degrees).“The presence of the nano-scale hair-like structure is responsible for the additional increase of 16 degrees in contact angle,” the scientists report. “The two-level roughness, in particular, the nano-scale hairs, amplifies the apparent contact angle and is responsible for the rolling behavior of the drops.”This study marks the first time that the effect of the nano-hairs has been isolated from the microstructure and chemical composition of the leaf. The results verify the importance of the nano-structure on the lotus leaf’s self-cleaning ability – an essential understanding for inventors designing self-cleaning products in the future.Reference: Cheng, Y T, Rodak, D E, Wong, C A and Hayden C A. “Effects of micro- and nano-structures on the self-cleaning behaviour of lotus leaves.” Nanotechnology 17 (2006) 1359-1362.By Lisa Zyga, Copyright 2006 PhysOrg.com Today, thousands of buildings boast self-cleaning paint and self-cleaning roofs; self-cleaning textiles, glass windows and sprays have already sprung onto the market. German botanist Wilhelm Barthlott has even owned a patent, copyright and trademark on this self-cleaning phenomenon since 1997. But despite the development of these practical applications, scientists still have a lot to learn about the specific mechanisms behind self-cleaning – or the so-called “Lotus Effect.” 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 lotus – a type of water lily native to Asia – has had its praises sung for thousands of years. In religious symbolism, Buddha often sits on a lotus leaf. Hindus view the lotus blossom as a symbol of divine beauty, associating the unfolding of the petals with the expansion of the soul. More recently, botany and nanotechnology have united to explore not only the beauty and cleanliness of the leaf, but also its lack of contamination and bacteria, despite its dwelling in dirty ponds. In recent years, scientists have developed theoretical models of the underlying mechanisms of the lotus leaf’s self-cleaning properties. Basically, the lotus leaf has two levels of structure affecting this behavior – micro-scale bumps and nano-scale hair-like structures – coupled with the leaf’s waxy chemical composition. However, research has not included a systematic, experimental investigation isolating structural and compositional effects, until now. “What are the mechanisms giving rise to the lotus effect?” asked scientists from Michigan (Y. T. Cheng et al) who published a paper in Nanotechnology on February 10. “We are able to separate the effects of nanometer features from micrometer roughness… [which] may help design self-cleaning surfaces and improve our understanding of wetting mechanisms.” The self-cleaning property of the lotus leaf – and applications derived from nature’s model – requires the surface to have roughness on two scales. When a raindrop falls on a lotus leaf, it forms a high contact angle (greater than 90 degrees), which means that it beads up rather than spreads out, as a liquid with a low contact angle (less than 90 degrees) would. A lotus leaf can have a contact angle close to 170 degrees, making it extremely hydrophobic. (For reference, human skin is slightly hydrophobic with about a 90-degree contact angle.) In fact, as little as 2-3% of the raindrop actually contacts the surface of a lotus leaf due to the waxy composition of the leaf, and to the air trapped between the raindrop and the leaf’s micro- and nano-structures. With such a small amount of contact between water and leaf, the raindrop rolls – rather than slides – down the leaf with little friction. The drop collects dirt and bacteria on its way, and in effect cleans itself. center_img These images from a scanning electron microscope compare (a) an untreated lotus leaf, with micro- and nano-scale structures, with (b) an annealed lotus leaf, where the nano-hairs have been melted away. The annealed leaf restricts the rolling, self-cleaning ability of raindrops. Image source: Cheng, Y. T. et al. Due in part to the micro- and nano-scale structures of the lotus leaf and the air trapped in between, only 2-3% of a raindrop actually contacts the leaf surface, and then rolls off. Image source: Wolf Friedmann. Citation: Scientists confirm role of nano-hairs in self-cleaning lotus leaf (2006, February 17) retrieved 18 August 2019 from https://phys.org/news/2006-02-scientists-role-nano-hairs-self-cleaning-lotus.htmllast_img read more

first_img(PhysOrg.com) — Today the Wall Street Journal changed a few things in its Verizon iPhone story from yesterday. Unnamed sources are now stating that Verizon Wireless will be selling a CDMA version of the Apple iPhone next year. WSJ has stated that Apple’s plans are to start mass production of the new CDMA version iPhone by the end of this year and making the phone available sometime in the first quarter of 2011. According to WSJ sources, the device will be built by Pegatron Technology Corp., a division of ASUSTeK in Taiwan.It has also been stated in the WSJ article that Verizon has been meeting with Apple and adding network capacity in preparation for the iPhone launch. At a press conference yesterday, Verizon Communications president Lowell McAdam had the following to say while referring to Apple: “At some point our business interests are going to align. I fully expect it, but I don’t have anything to say.”Industry speculation has it that Apple will also be preparing an iPhone that will support Verizon’s LTE network but would not be announced until June of 2011. Verizon LTE will have a 38 city presence by Q4 and is not expected to have an anticipated large presence until the middle of next year. WSJ undisclosed sources have also mentioned that Apple is preparing an iPhone with a new form factor hinting that it will be for Verizon’s LTE. © 2010 PhysOrg.com Citation: Verizon iPhone in Q1 not a rumor any longer (2010, October 7) retrieved 18 August 2019 from https://phys.org/news/2010-10-verizon-iphone-q1-rumor-longer.html Explore further Verizon says fast 4G wireless coming to 38 cities 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

first_img (c) 2012 Phys.org Rainbow Trout (Oncorhynchus mykiss). Image: Knepp, Timothy – U.S. Fish and Wildlife Service More information: Magnetic characterization of isolated candidate vertebrate magnetoreceptor cells. S.H.K. Eder, H. Cadiou, A. Muhamad, P. A. McNaughton, J. L. Kirschvink, M. Winklhofer. www.pnas.org/cgi/doi/10.1073/pnas.1205653109AbstractOver the past 50 y, behavioral experiments have produced a large body of evidence for the existence of a magnetic sense in a wide range of animals. However, the underlying sensory physiology remains poorly understood due to the elusiveness of the magnetosensory structures. Here we present an effective method for isolating and characterizing potential magnetite-based magnetoreceptor cells. In essence, a rotating magnetic field is employed to visually identify, within a dissociated tissue preparation, cells that contain magnetic material by their rotational behavior. As a tissue of choice, we selected trout olfactory epithelium that has been previously suggested to host candidate magnetoreceptor cells. We were able to reproducibly detect magnetic cells and to determine their magnetic dipole moment. The obtained values (4 to 100 fAm2) greatly exceed previous estimates (0.5 fAm2). The magnetism of the cells is due to a μm-sized intracellular structure of iron-rich crystals, most likely single-domain magnetite. In confocal reflectance imaging, these produce bright reflective spots close to the cell membrane. The magnetic inclusions are found to be firmly coupled to the cell membrane, enabling a direct transduction of mechanical stress produced by magnetic torque acting on the cellular dipole in situ. Our results show that the magnetically identified cells clearly meet the physical requirements for a magnetoreceptor capable of rapidly detecting small changes in the external magnetic field. This would also explain interference of ac powerline magnetic fields with magnetoreception, as reported in cattle.Press release Finding the parts of the body that are able to sense a magnetic field, called magnetoreception, has been difficult because of the nature of magnetism. Like sound or light, it strikes the entire body, but unlike the other two stimuli, it can also penetrate the skin and keep on going, meaning receptors could reside virtually anywhere in an organism. Logically though, such receptors would be more likely to reside in the head somewhere, in close proximity to the brain. In migrating fish, the suspicion has been that a good place for such cells would be inside the nose, as fish seem to follow it as they swim.To find out if this is the case with rainbow trout, the team took a sample of olfactory epithelium from the snout of one such specimen and placed it inside a ring of rotating magnets. Then they looked at the specimen under a microscope and found individual cells that spun around on their axis following the artificially induced magnetic field. Upon closer inspection of the cells, the team found iron-rich crystals, most likely single-domain magnetite sitting at just one end of the cell, very near the membrane; which makes sense. To cause a spin, the magnetite would need to be at the tip of a cell just as it is on the tip of a needle in a compass. Only a few of the cells were found, leading the researchers to estimate that the tissue likely holds just one such cell out of ten thousand capable of responding to a magnetic field.Of course the finding doesn’t actually prove that the cells are responsible for the fish’s ability to navigate long distances, but it does seem likely to be the case. The trick now will be to show how cells that move in response to a magnetic field are able to convey a message to the brain. Citation: Researchers find cells that move in response to Earth’s magnetic field (2012, July 10) retrieved 18 August 2019 from https://phys.org/news/2012-07-cells-response-earth-magnetic-field.html Explore furtherlast_img read more

first_img News of their findings appears in the IEEE Spectrum, discussing flash memory’s limitations and the Taiwan company’s solution. Macronix is a manufacturer in the Non-Volatile Memory (NVM) market, with a NOR Flash, NAND Flash, and ROM products. Before their solution announcement, though, many engineers inside and outside of Macronix were aware of a life-giving workaround: heat. The snag is that applying heat was not found to be practical. As the Macronix team put it, the “long baking time is impractical for real time operation.” Although subjecting the cells to high heat could return memory, the process was problematic; the entire memory chip would need heating for hours at around 250 °C.
 They redesigned a flash memory chip to include onboard heaters to anneal small groups of memory cells. Applying a brief jolt of heat to a very restricted area within the chip (800 degrees C) returns the cell to a “good” state. They said that the process does not have to be run all that often. According to project member Hang‑Ting Lue, the annealing can be done infrequently and on one sector at a time while the device is inactive but still connected to the power source. It would not drain a cellphone battery, he added.
 Macronix estimates that the flash memory cells could beat the 10,000 cycle limit by lasting for as much as for 100 million cycles but a commercial product is not imminent. Instead, Macronix will present their approach—very high temperature in a very short time— this month at the IEEE International Electron Devices Meeting (IEDM) from December 10 to 12 in San Francisco. This is the forum for presenting breakthroughs in semiconductor and electronic device technology. Lue observed that in coming up with the approach, his team would not be able to lay claim to any new physics principle. “We could have done this ten years ago.” He said it took merely a leap of imagination into a different “regime.”For their upcoming IEEE presentation, they said they propose and demonstrate a novel self-healing flash, where a high temperature (>800°C), and short time annealing are generated by a built-in heater. “We discover that a BE-SONOS charge-trapping NAND Flash device can be quickly annealed within a few milliseconds,” they said. Their presentation is titled “Radically Extending the Cycling Endurance of Flash Memory (to > 100M Cycles) by Using Built-in Thermal Annealing to Self-heal the Stress-Induced Damage.” The authors are H.-T. Lue, P.-Y. Du, C.-P. Chen, W.-C. Chen, C.-C. Hsieh, Y.-H. Hsiao, Y.-H. Shih, and C.-Y. Lu. © 2012 Phys.org 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. Explore further More information: m.spectrum.ieee.org/semiconduc … s-100-million-cycleswww.his.com/~iedm/program/sessions/s9.html Citation: Taiwan engineers defeat limits of flash memory (2012, December 2) retrieved 18 August 2019 from https://phys.org/news/2012-12-taiwan-defeat-limits-memory.html (Phys.org)—Taiwan-based Macronix has found a solution for a weakness in flash memory fadeout. A limitation of flash memory is simply that eventually it cannot be used; the more cells in the memory chips are erased, the less useful to store data. The write-erase cycles degrade insulation; eventually the cell fails. “Flash wears out after being programmed and erased about 10,000 times,” said the IEEE Spectrum. Engineers at Macronix have a solution that moves flash memory over to a new life. They propose a “self-healing” NAND flash memory solution that can survive over 100 million cycles. Credit: MemoTrek Samsung Samples First 50-nanometer 16Gb NAND Flash for Solid State Diskslast_img read more

first_img 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. Captive mice and native mice don’t care to breed together, study finds Credit: CC0 Public Domain A team of researchers from the University of Wollongong and the University of New South Wales has found that some wild animals undergo internal physical changes when bred in captivity. In their paper published in the journal Royal Society Open Science, the group describes experiments they conducted on captive mice and what they found. Journal information: Royal Society Open Science Citation: Animals bred in captivity found to undergo internal physical changes (2018, May 9) retrieved 18 August 2019 from https://phys.org/news/2018-05-animals-bred-captivity-internal-physical.htmlcenter_img As scientists and animal management teams seek to save dying species from extinction, they often look for ways to save them. In addition to restoring natural habitats, some have taken to capturing specimens in the wild in the hopes of breeding them in captivity. The offspring (or generations of offspring) are then released back into the wild. For a variety of reasons, such efforts are not always successful. One of those, the researchers with this new effort have found, is there might be morphological changes that impede ability to survive.The researchers note that few studies have been done surrounding the morphological impact on wild animals bred in captivity. Also, relatively unknown is the impact that captivity has on animals after multiple generations have been bred.To learn more about how captivity might impact wild animals, the researchers compared the internal and external morphology of wild and captive house mice. They report that after just one generation, the mice showed no visible external changes. They also report that sexual dimorphism was maintained. But, they did find an internal change. The captive mice had lighter combined kidney and spleen masses. The change, the team notes, was not due to a difference in diet, but to the conditions under which the mice lived. Easy meals, they note, put less demand on those organs. Nature responded by making them smaller. The team notes that shrinking organs or other internal morphological changes could make it difficult for animals to survive once they are released into the wild. That would make the whole endeavor moot.The researchers note that theirs was just a single case, but believe that their findings are revealing. They suggest that it is likely that other wild animals bred in captivity could have the same or other changes. This means that many more studies are required before breeding programs are instituted. © 2018 Phys.org Explore further More information: Stephanie K. Courtney Jones et al. Effect of captivity on morphology: negligible changes in external morphology mask significant changes in internal morphology, Royal Society Open Science (2018). DOI: 10.1098/rsos.172470AbstractCaptive breeding programmes are increasingly relied upon for threatened species management. Changes in morphology can occur in captivity, often with unknown consequences for reintroductions. Few studies have examined the morphological changes that occur in captive animals compared with wild animals. Further, the effect of multiple generations being maintained in captivity, and the potential effects of captivity on sexual dimorphism remain poorly understood. We compared external and internal morphology of captive and wild animals using house mouse (Mus musculus) as a model species. In addition, we looked at morphology across two captive generations, and compared morphology between sexes. We found no statistically significant differences in external morphology, but after one generation in captivity there was evidence for a shift in the internal morphology of captive-reared mice; captive-reared mice (two generations bred) had lighter combined kidney and spleen masses compared with wild-caught mice. Sexual dimorphism was maintained in captivity. Our findings demonstrate that captive breeding can alter internal morphology. Given that these morphological changes may impact organismal functioning and viability following release, further investigation is warranted. If the morphological change is shown to be maladaptive, these changes would have significant implications for captive-source populations that are used for reintroduction, including reduced survivorship.last_img read more

first_imgGo green, save the environment – has been a constant concern put across by people from all walks of life. Raising the issue and lending their contribution are the two young environmental architects- Alankrita Soni and Smita Dixit Mehra.The duo have designed Dreamatix, an exhibition consisting of pieces of art, sculpture and lifestyle products that are contemporary, trendy, fashionable and yet sustainable and most importantly – environment friendly. Also Read – ‘Playing Jojo was emotionally exhausting’The underlying theme of the 20 products on display is to address issues related to environmental degradation, global warming and climate change in a very unique way through art and life style products divided in four categories – The Marine Life, The Plant Life, The Animal Life and the Change in Climate.Some of their exhibits are, Sangmungia- The Coral Clock-Mirror and the Table where they have used waste PVC pipes from construction sites to create it. Suryamukhi – The Sunflower Chair is a beautiful well-crafted chair which takes its inspiration from a Sunflower and is made out of waste tyres. Also Read – Leslie doing new comedy special with Netflix‘As an environmentally conscious and nature loving architects we always wanted to bring style in living through green ways and to help establish a new fashion that appreciates nature. Each product that we create is a shadow of our underlying design philosophy. We believe in re-using and re-creating before recycling – Upcycling is the way forward,’ said the duo.DETAILAt: Open Palm Court, India Habitat Center On Till: 25 March Timings: 10 am – 7 pmlast_img read more

first_imgArt is the most intense mode of individualism that the world has known. And with that thought in mind head over to artist DP Sibal’s exhibition on display in the Capital. Titled Nature, Space and Beyond and on display at The Gallery on MG, the exhibition invites the art connoisseurs to witness the artists’ spectrum of creativity and his abiding love for painting.An artist of diverse talents, DP Sibal is a life fellow of the International Institute of Arts and Letter for his outstanding creativity. He has been a recipient of many prestigious awards like the Aadharshila, Indo-French Friendship Association Award and National Award of Avantika.  Also Read – ‘Playing Jojo was emotionally exhausting’He also represents Aotearoa New Zealand Guild of Artists Trust – (Supporting member Asia Pacific Cultural Center for UNESCO) and Janacia Trust Associates (United Nations nongovernmental movement of artists working for environment and world peace) and has also been honored by AIFACS.His work has been presented and displayed across the world including in the collection of NGMA, LKA, UNDP, IFFCO, Bharat Bhavan, University of Peace, Costa Rica and several important private collections in India and abroad. A must for the art lovers – head over!last_img read more