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| SCIENCE & TECHNOLOGY |
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Boosting optical communication Beep and there’s your ticket!
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Boosting optical communication It was the invention of laser that gave a big push to the growth and popularity of optical communication systems. Similarly the perfection of wavelength data division multiplexing technique with optical amplifiers for amplifying signals in the fibre paved the way for the rapid transmission of dense and huge volume of data. Clearly and apparently, the optical frequencies of light beams moving through the optical fibres are quite high in contrast to the conventional radio waves and microwaves. This implies that a high-speed beam is capable of carrying far more higher volume of data in comparison to radiowaves and microwaves. The efficiency of the third generation fibre optical systems now in use has been boosted by a significant extent through the introduction of optical amplified repeaters. And now researchers and communications engineers are talking of the possibility of developing a hollow optic fibre that would have the potential to carry hundred fold more data than most efficient fibre optic system now in use. In the hollow fibre optic system which is now under experimental phase, infrared wavelength of light will serve as the medium of data transmission. But as things stand now, a lot of ground work would need to be done before such a system becomes a reality. Corning, the pioneer of fibre optic systems, has successfully tested a hollow optic fibre under controlled laboratory conditions. Meanwhile, breakthroughs achieved in developing higher efficiency optical switches and light emitting transistors could lead to the further improvement in the efficiency of the existing fibre optic systems. Researchers at the University of Stanford and Massachussets Institute of Technology have designed a optical switch which is smaller than a micron, requires little power and can be fabricated in any well equipped chip manufacturing facility. This device is made of photonic crystals and uses the elliptical, perpendicular rod as an optical cavity to store light energy for brief spells. This allows the device to act as switch because the stored energy changes the angle of refraction, blocking light from moving through a nearby waveguide. On another front a high efficiency light emitting transistor designed by a team of researchers at the Americans academic institutions is capable of “interconnecting optical and electrical signals for communication purposes”. This light emitting transistor is made of indium gallium phosphide and gallium arsenide. Parallelly, the so-called free space optics also called optical wireless is emerging as an ideal solution for providing last mile connectivity in otherwise difficult-to-reach areas by sending signals through the atmospheric medium by means of laser transmission. This innovative technique which is well suited for bridging the last mile connectivity obviates the need for laying optical fibres in congested urban centres and remote rural locations. As it is, the free space optics which is simple to use and efficient in operation involves the application of directed beam of light radiation between the two end points to transmit the data. This technique has been in use for more than three decades now. Free space optics can be used to provide high speed communications links to remote locations, and disaster hit areas as well as paving the way for rapid metro connectivity. |
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section of the audience at a recent pop concert in Sydney were probably unaware that they were on the cutting edge of computer technology. Around one in five of those in the auditorium listening to Jet had received their tickets over their mobile phones in the form of text message that included a bar code. The ground-breaking Mobi-ticket experiment was run by Australia's Aurora Digital. Rather than collecting the tickets they had paid for over the phone with a credit card number, the Mobi-ticket adopters had the text message scanned at the box office and in they went. The downside to some fans is that, without a ticket, they have no souvenir of their Jet concert. The upside, say Aurora Digital executives, is that Mobi-tickets are cheaper to produce than the real thing and so should bring down the cost of a |
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Why is it cool on hilly areas? LET us start with the earth with an envelope of air we call the atmosphere. The atmosphere has pressure. This pressure can be considered as weight of the air column. At sea level this is a little over a kilogram per centimeter square. As we go higher there is less and less air above. This means that the pressure of the air must decrease with increasing altitude. This would imply that if I take one litre of air from sea level to an altitude where the pressure is reduced to one half that at sea level, the volume occupied by that air would become twice i.e. 2 litres. Air expands when its pressure is reduced. But we also know that when air expands it cools. If you do not know this you can check it easily by confirming that when you press the valve pin of an inflated car tyre the escaping air is cold. Also, you must have noticed that when you are pumping air into your bicycle tube the hand pump gets warmer. The reason for this is because the random energy of the air molecules is reduced when they move further apart from each other; this happens because the molecules have to work against the attractive force between the gas molecules. Thus the natural stable state of the atmosphere is one in which the temperature decreases as the pressure decreases — in other words as the altitude increases. That is why it is cold on mountains. You must also remember that air is heated primarily through contact with the ground and infrared radiation coming up from the earth surface. Little sunlight is absorbed by the atmosphere on its way down to the earth. In spite of the tremendous repulsion between positive charges, how can so many protons reside in the atomic nucleus? We know that helium2 (He2) does not exist. In other words we cannot have a nucleus with only two protons. But He3 does exist. The nucleus of He3 has a neutron in addition to two protons. The reason is that there is strong short-range nuclear force between all nucleons — protons and neutrons — alike. The character of this short-range force, called the Strong Force, is different from that of the electrical force. Thus inside the nucleus we have two opposing forces — repulsion between positively charged protons and attraction between protons and neutrons. With increasing atomic numbers, the number of neutrons is significantly greater than the number of protons. Thus the abundant form of Uranium has a total of 146 neutrons and only 92 protons. What
happens if protons and anti-protons are allowed to hit each other? There was a useful imagery suggested by Paul Dirac when he gave the theory of the electron way back in 1930. It was suggested that when an electron is created a hole is left in the vacuum. This hole would behave like an anti particle of electron. It would have a positive charge. Thus was born the concept of particles and antiparticles. Incidentally the positive electrons, later called positrons, were discovered after Dirac did his work. Thus, given enough energy a proton and antiproton pair can also be created from vacuum. And the reverse, that when a proton and an antiproton meet their rest mass energy would be released in the form of particles of lower energy, including electromagnetic energy. Thus a proton can annihilate an antiproton producing a burst of energy. The energy released in a quiet handshake of the two would be given by the Einstein equation E = Mc^2, where M is twice the mass of a proton and c the velocity of light. All this has been completely established experimentally. |
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‘Teleportation’ breakthrough SCIENTISTS in Austria and the United States say they have “teleported” the properties of one atom to another, an achievement that brings closer the dream of super-fast quantum computers. Far from being the teleportation of “Star Trek” in which Captain Kirk, Spock and Bones get beamed from the starship Enterprise to a distant planet, the experiment is rather more prosaic. It entails transferring the key signatures of one atom to another nearby, in closely controlled lab conditions. Is champagne the real thing? Spanish scientists have developed a test that can prove whether champagne is the real thing or just another sparkling wine. The test recognises a characteristic mix of trace metals from soil around France’s Champagne region where the grapes for the real thing are grown. Mystery of rock carvings Records and examples of over 950 prehistoric rock art panels exist in Northumberland, which are of the traditional 'cup and ring' variety, with a typical specimen featuring a series of cups and concentric circles pecked into sandstone outcrops and boulders. However, archaeologists at the University of Newcastle upon Tyne, who are studying prehistoric rock carvings, are baffled by three unusual markings found carved into rocks at separate locations. They consist of a small heart shape and a stylised carving of a human face, both found near prehistoric rock carvings close to Rothbury, and one discovered near Wark, which is such an unusual combination of lines and circles that it is impossible to say what it depicts. The usual 'cup and ring' marks are thought to have been made thousands of years ago by Neolithic and Early Bronze Age people. However, experts think the newly-discovered mystery marks could be much younger, with the heart and the face shapes potentially as little as 100-250 years old. Darwin’s theory and F1 cars Charles Darwin’s theory of evolution could be used to ‘’breed’’ a new generation of enhanced Formula One racing cars, British computer scientists said. Researchers at University College London have demonstrated in simulations that it was possible to knock crucial tenths of a second off a lap time by tailoring a car’s setup to whatever conditions are faced on the track. Scientists applied genetic algorithms — software that mimics evolution’s drive for fitness — to breed the best tuning configurations for racing cars. Biological clock
speed Scientists have developed a method that aims to predict how fast a woman’s biological clock is ticking and when she is likely to go through menopause. By measuring the volume of ovaries with ultrasound, researchers in Scotland said they can predict the reproductive age of a woman aged 25 to 51, or how many eggs she may have left, which could dramatically change fertility treatments. |
BECAUSE of its efficiency, speed and high bandwidth the optical communication systems are fast becoming popular around the world. As it is, the optical communication systems have drastically reduced the cost of long-distance data communications. In fact, a burgeoning need for the transmission of a variety of data has given big boost to the widespread use of fibre optics communication systems.
Archaeologists have found a trio of extraordinary stone carvings while charting the phenomenon of prehistoric rock markings in Northumberland, close to the Scottish border in the United Kingdom.