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| SCIENCE & TECHNOLOGY |
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Wearing the electronics Harnessing
the sunlight Trends Prof Yash
Pal
THIS UNIVERSE |
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Wearing the electronics Textiles Intelligence has identified a wide range of smart fabric technologies like wearable electronics, heat conductive textiles, textile switches and shock absorbing fabrics. The fabrics could be velvet, denim or nice chintz — whatever you want and you can have your mobile phone keypad in the sleeve of your jacket.” People were initially reluctant to have wires and hard plastic cases in their dresses due to its hard look and uncomforting to the body. But now, electronic circuits can be built entirely out of textiles and are able to distribute data and power, and perform touch sensing. The U.K. component developer Eleksen Ltd has developed a technique that weaves wires into clothes to turn them into something called clever clothes, thus, making the gadgets wearable and washable. The technique has been used for the fabrication of jacket phone and palmtop computer trousers. Several circuits such as busses to connect various digital devices, microcontroller systems to sense proximity and touch, and all-fabric keyboards and touch pads have already been built either on fabric or with fabric. ElekTex, the core product of Eleksen Ltd, is an electrically conductive fabric, which bends and flexes, just like normal clothing fibre, and is rugged enough to wear. It can be washed in washing machine without any damage. Among the first applications of ElekTex is a rolled-up cloth keyboard. The fabric is printed with an alphanumeric keyboard, but with another software interface, the same fabric can act as a digital drawing pad. Eleksen Ltd. has supplied touch-sensitive fabric controls to O’Neill, a wetsuit and sports gear maker, for the products like ski jackets with integrated, machine-washable controls for audio players. These fabric controls are made up of a multilayered fabric having three electro-active layers. Two outer conductive layers surround an inner resistive layer that separates the conductive layers until someone presses them together. The fabric is basically an open circuit until someone presses it. When pressed, there is voltage drop at various points on the surfaces; the measurement of voltage drop determines where and how hard someone has pressed the fabric. The keyboards make use of a single layer of fabric and are based on capacitive sensing. Here, an array of embroidered or silk-screened electrodes makes up the points of contact. A finger’s contact with an electrode results in the increase of electrode’s total capacitance. These capacitive sensing arrays can also be used to tell how well the clothes fit the wearer, because the signal varies with pressure. Such a keypad is flexible, durable, and responsive to even mild touch. In a test application, 50 denim jackets were embroidered in this pattern. The results of the keyboard to touch and timing were found to be excellent. Pressing of the cloth deforms the wires, thus, changing their conductivity. Just like a computer screen, the fabric can have different resolutions by weaving more or less conductive wires into the cloth. |
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Smart fabrics aren’t only about sensing but they can also be used for generating electrical power based on the technology developed by Konarka. Daniel McGahn, Konarka’s, executive vice president says that everything you think about when you hear ‘solar’ is rigid. The company’s multi-layer coatings on the fabrics can function as photovoltaic cells. These multi-layered coatings contain an active layer in which a variety of organic polymers and nano-scale additives work together to absorb the light photons and photo-electrons are generated. Usually, the active layer is sandwiched between two outer layers that serve as electrodes. The coating can be tailored to act as photo detectors and be tuned to a broad spectrum of light or to narrow bands. It can be a UV sensor or near infrared. There are coatings, which have the ability to reflect a given color spectrum. And this ability opens up many opportunities to use the coatings to create graphics, patterns, or logos into fabric products. The company has worked out two ways of harnessing power from fabrics. The first is the “Powerplastic” solar materials, in which the photo-active coating goes on thin, flexible sheets of plastic. These sheets can easily be incorporated into a variety of fabric structures. The second way is to apply the coatings directly to fabric fibers, a technology called Powercloth. Both the approaches offer design advantage for those used to working with rigid photovoltaics. More than 70 per cent of the surfaces we daily interact with are textiles. This available surface area can harvest the sun’s energy as opposed to finding room for a solar array. Another potential advantage relates to its ability to generate power in low light conditions. At half the sun’s intensity, these flexible solar substrates generate 3-6 times more power than a rigid photovoltaic cell. Further, the technology is also capable of generating some power from artificial light or from sunlight filtered through windows. Presently, the smart fabrics industry is a $340 million industry and growing at a rate of 19% annually. Although it is still in its infancy, but the potential for rapid growth in military, medical and sporting equipment is high. Particularly, due to increased health awareness, smart fabrics are being integrated into sport and medical equipment, as well as implantable systems for monitoring heart rate, body temperature and other biophysical characteristics. The health and medical industries will be large markets in future, the biggest market initially may be the military where liquid armor, electrical signal currents, light energy and wireless multimedia devices imbedded in clothing are being developed. Clothing in future will be designed with built-in switches or joysticks to control equipment for electronic entertainment, particularly iPods. The key components are smart textiles which, are sensitive to pressure and can be stitched, stapled or glued. Gloves made up of a special conductive yarn would be used for controlling computers, games consoles, machines and other electronic devices remotely. These textiles can help in building flexible sensing systems, detect chemicals, generate mobile power and perform other tasks. — P.S. |
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Trends If made into a shirt, the fabric could harness power from its wearer simply walking around or even from a slight breeze, they reported Wednesday in the journal Nature. “The fiber-based nanogenerator would be a simple and economical way to harvest energy from the physical movement,” Zhong Lin Wang of the Georgia Institute of Technology, who led the study, said in a statement.
— Reuters Rare bird found in Myanmar The discovery in early February comes only months after Russian researchers reported that numbers of the tiny birds — with speckled brow feathers and a distinctive spoon-shaped bill — had dropped 70 per cent in the past few years in their breeding sites in Siberia and none had been seen this year in their traditional wintering sites in Bangladesh, Britain-based conservation group BirdLife International said. The World Conservation Union lists the bird as endangered with only 200 to 300 pairs left in the wild.
— AP Dino that ate like sharks Fossils from two newly discovered meat-eating dinosaurs that lived in the Sahara Desert 110 million years ago paint a fearsome picture of life in Africa’s Cretaceous period, which appears to have been teeming with unusual carnivores. University of Chicago paleontologist Paul Sereno unearthed Kryptops palaios, a short-snouted, hyena-like beast, and Eocarcharia dinops, a shark-toothed, bony-browed killer in a 2000 expedition. Both were about 25 feet in length — and on the prowl for meat.
— Reuters Bats could fly before “radar” A fossil found in Wyoming has apparently resolved a long-standing question about when bats gained their radar-like ability to navigate and locate airborne insects at night.
The answer: after they started flying. The discovery revealed the most primitive bat known, from a previously unrecognised species that lived about 52 million years ago. Its skeleton shows it could fly, but that it lacked a series of bony features associated with “echolocation,” the ability to emit high-pitched sounds and then hear them bounce back from objects and prey, researchers said.
— AP |
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THIS UNIVERSE Couldn’t God have made an earth that had no earthquakes, volcanoes or Tsunamis?
I do not know, but I very much doubt. Firstly it is wrong to think that the earth was specially designed to suit the taste of a species that would make its appearance billions of years after the planet was put together! That would be much too arrogant for us to assume. We just happened to evolve and I am glad that we did, even if we were not in the original drawings or blueprint. More seriously, a planet without earthquakes, volcanoes or Tsunamis would have had several fundamental design deficiencies, mostly related to the fact that its interior would not have been hot and filled with molten rocks and metal. That would be impossible. Gravitational energy released during compaction of the scattered material from which the planet is formed cannot be avoided. This would be released as heat that would be most intense at the centre. Heat loss through the top layers would create a thermal gradient. Therefore convection currents in the molten core are inevitable. Rising hot material will cool at the top and would have to descend. The crust of the earth on top would break up and plate tectonics would be inevitable. Continents would drift around, join with each other and collide. At the boundaries of these plates there would be zones of upwelling through which lava would flow out to make a fresh ocean floor; and there would be subduction zones where the crustal material would be sucked in. All this activity would result in earthquakes and sometimes Tsunamis. New mountain ranges would be born along collision areas of plates and the earth would like to take a morphological character similar to what our planet has. Just imagine if all these happenings were not allowed to take place by heavenly subvention we would end up with a world without mountains and valleys. It could be completely round and, horror of horrors not a square metre of land to stand on. In fact an ocean nearly four kilometres deep would cover the whole planet. That could still support some forms of life, but not us. Incidentally, another design defect would soon become apparent. Since the earth would not have a conducting interior, the planetary rotation will not create a magnetic field — the earth will not act like a magnet. This would have been a big disadvantage for early explorers and navigators who would have had to live without their compasses. We would not have had the beautiful spectacle of auroras in the Polar Regions. But the greatest threat would have come from the fact that we would not have been shielded from cosmic rays. Therefore we have to accept that we live in the best possible world, in spite of all the earthquakes, Tsunamis and volcanoes. |
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Clothes are worn not only for enhancing the look of the body and but also to protect it from the vagaries of the nature. In recent years, the progress in chip technology has gifted many gadgets to bring comfort to human life. The traditional clothes know-how has been blended with digital technology and it is now possible to wear the electronics. This wearable electronics is the next generation of clothes called “smart fabrics”. 
U.S. scientists have developed a microfiber fabric that generates its own electricity, making enough current to recharge a cell phone or ensure that a small MP3 music player never runs out of power.
Eighty-four spoon-billed sandpipers have been discovered in a coastal stretch of Myanmar, offering hope for saving the endangered birds, a conservation group said Thursday.