Chandigarh, Thursday, August 19, 1999
Chandigarh, Thursday, August 19, 1999 |
Battery revolution in the offing by Shirish Joshi Dramatic advances in nickel-zinc batteries could lead to new type of electric bikes and scooters and may eventually change the shape and performance of car batteries Ambitious European comet chaser Electronic
voting machine |
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Battery revolution in the offing THE lead-acid battery under an automobile’s hood has not evolved radically since the 1940s. But in coming months, a battery revolution is going to sweep through the transportation sector in the US. In time to come it will come to India. Dramatic advances in nickel-zinc batteries could lead to new type of electric bikes and scooters and may eventually change the shape and performance of car batteries. Even before that happens, auto makers are looking closely at the product that weighs no more than a couple of kilograms, but will replace the standard 18-kg box of lead-acid car battery. Although totally new, this development is already shaking up the lead-acid battery manufacturers. In April, 1999, a small company in the US announced the development of a special class of nickel-zinc batteries that could be recharged 500 times. That’s five times as often as such lead-acid battery in use today. Another company in the US is developing the incredibly shrinking lead-acid batteries. The industry has experimented with nickel-zinc for nearly 50 years. But high material costs and poor performance have kept such batteries out of the mainstream. The chemical compound is more energy-dense and is less toxic than lead-acid. But the batteries tend to drain quickly and expire after being recharged just 50 to 100 times. The new company’s patented solution involves adding calcium to the zinc electrodes to prevent chemical degradation. That boosts the number of charges and lets the company pack more power into a smaller sized battery. The new batteries weigh half as much as lead-acid and run up to three times as long on each charge. Nobody has seriously come to market with an excellent replacement for lead-acid unit now. This one innovation could open up a whole new category that includes electric bikes and scooters. Such vehicles have failed in the past, mainly because the battery of a typical model must be recharged every 40 km. Petrol powered equivalents can travel eight times as far on just a 20-litre tank. The company cannot match that, but the engineers feel that the new batteries will do 80 km per charge — and last two times as long as the lead-acid variety. This is the best chance of developing an improved electric bike or scooter. Such vehicles would be specially appealing in those parts of Asia and Europe where automobiles don’t rule the roads The company has purchased shares in a Chinese industrial unit manufacturing batteries. It expects to announce sale of its new nickel-zinc batteries by the end of the summer. Skeptics say nickel-zinc is too expensive to justify most of the product applications the company has in mind. And there are other problems: The batteries tend to develop chemical growths called dendrites, which cause them to short. The company has solved the problem by adding calcium, and by the sealed construction of the battery. The company is already looking beyond scooters and bikes, to next-generation of battery-powered lawn movers, wheelchairs, and power tools etc. The other company plans to increase the power density of lead-acid batteries by coiling thin sheets of metal into compact cylinders. The result: about five times the power density of other rechargeable batteries. The company’s first entry into the market this winter will be a compact starter for light aircraft. The device is just 33 cm long and weighs about 3 kg. In the next few months, the company will come out with a lighter 25-cm unit for emergency starting of cars when the battery is discharged. It can stay in the trunk for a year without losing all its energy. Car batteries are a logical next step for the other company. A 2.3 Kg battery made by the other company could replace the starting function of an 18-Kg car battery. They are also looking at cordless power tools. Their automated production line is ready to produce four million batteries a year. Another company has found a way to wind battery plates together, thus increasing the energy density and shelf life. Its product, which hit the market in May, also has new safety features that allow it to be placed anywhere in the car. In fact, all three approaches have shortcomings. For example, none is robust enough right now to serve as a primary battery for an electric vehicle. But that won’t stall the momentum that’s building in this long-neglected arena. In a few months, consumers will get a chance to road test some of the new technologies themselves. A battery also called an electric cell is a device that converts chemical energy into electricity. Strictly speaking, a battery consists of two or more cells connected in series or parallel, but the term is also used for single cells. Batteries in which the chemicals can be reconstituted by passing an electric current through them in the direction opposite that of normal cell operation are called secondary cells, rechargeable cells, storage cells, or accumulators. The storage battery was invented in 1859 by the French physicist Gaston Plante. Plante’s cell was a lead-acid battery, the type widely used even today. The lead-acid battery, which consists of three or six cells connected in series, is used in automobiles, trucks, aircraft, and other vehicles. Its chief advantage is that it can deliver a strong current of electricity for starting an engine; however, it runs down quickly. It has a very low power
density or in other words, it weighs far too much for the
amount of electricity it stores. The electrolyte is a
dilute solution of sulphuric acid; the negative electrode
consists of lead, and the positive electrode of lead
dioxide. |
Ambitious European comet chaser THE 14-nation European Space Agency (ESA) has unveiled an ambitious plan to study the comet Wirtanen from very close quarters using the robotic Rosetta spacecraft. As envisaged now, the Rosetta mission will place a lander on the surface of the comet and chase with an orbiter, the comet for millions of kilometres through space. Comets — among the oldest (4.6 billion years) and last altered objects in the solar system — are regarded as the building blocks from which the planets formed. Thus the Rosetta discoveries will allow the scientists to learn more about the birth and evolution of the planets and about the origin of life on earth. “Rosetta is a mission of major scientific importance”, says Prof. Roger Bonnet, Director of ESA’s science programme. “It will build on the discoveries made by Giotto and confirm ESA’s leading role in the exploration of the solar system and the universe as a whole.” Rosetta is planned to be launched by an Ariana booster from Kourou spaceport in French Guiana in January, 2003. In order to gain sufficient speed to reach the distant comet, Rosetta will require gravity assists from the earth and Mars. After swinging around Mars in May, 2005, Rosetta will return to earth’s vicinity in October, 2005 and October, 2007, before heading away from the sun towards comet Wirtanen. As it bounces round the solar system, Rosetta will also make two excursions into the main asteroid belt where it will obtain the first close-up images and information on two contrasting objects — 4979 Otawara and 140 Siwa. Scientists speculate Otawara is less than 20 km across, whereas Siwa is probably 110 km in diameter, much larger than any asteroid which has so far been studied using spacecraft missions. Rosetta will fly to within 1000-km of Otawara in July, 2006, followed by a similar rendezvous with Siwa two years later. However, the most difficult phase of the mission will be the final rendezvous with the fast moving comet. Thus after a 5.3 billion km space odyssey, Rosetta will make the first contact with Wirtanen. At that particular place, sunlight is 20 times weaker than on earth, and the comet’s nucleus will still be frozen and inactive. Once the navigation teams are able to determine the comet’s exact location from images returned by the spacecraft’s camera a series of braking manoeuvres will allow Rosetta to match speed and direction with its target. After about seven months of edging closer, Rosetta will eventually be within 2 km of Wirtanen’s frozen nucleus. From its close orbit above the tiny nucleus, Rosetta will be able to send back the most detailed images and information ever obtained of a comet. When a suitable landing site has been chosen, about a month after global mapping starts, the orbiter will release a 100-kg lander on to the comet’s solid surface. Touch down must be quite slow-less than one metre per second to allow for the almost negligible gravitational pull of the tiny nucleus. In order to ensure that the lander does not bounce and disappear into space, an anchoring harpoon will be fired into the surface immediately on impact. By this time, the warmth of the sun will probably have begun to vaporise parts of the nucleus, initiating some form of surface organising. For a period of about a month, data from the lander’s eight experiments will be relayed to earth via the orbiter. They will send back unique information on the nature and composition of the nucleus. Meanwhile, as Comet Wirtanen approaches the sun the Rosetta orbiter will fly alongside it, mapping its surface and studying changes in its activity. As its icy nucleus evaporates, 12 experiments on the orbiter will map its surface and study the dust and gas particles it ejects. For the first time, scientists will be able to monitor at close quarters the dramatic changes which take place as a comet plunges to sunwards a speed of 46,000 kmph. By mission’s end in July, 2013, Rosetta will have spent almost two years chasing the comet for millions of kilometres through space. It will also have returned a treasure trove of data, which will enable us to learn more about how the planets formed and where we came from. For centuries, comets have inspired awe and wonder. Many ancient civilisations saw them as portents of death and disaster, omens of great social and political upheavels. Shrouded in thin, luminous veils with tails streaming behind them, these “long haired stars were given the name “comets” by the ancient Greeks. The most popular theory about the nature of comets was put forward by American astronomer Fred Whipple, who believed they were like dirty snowballs — large chunks of water ice and dust mixed with ammonia, methane and carbon dioxide. As they approach the sun, their outer icy surface begins to vaporise, releasing large amounts of dust and gas to form the surrounding coma and wispy tails. Comet Wirtanen, the
target of Rosetta is a chunk of dirty ice less than 1-km
across which orbits the sun once every five and a half
years. Wirtanen was chosen for the mission because it is
much easier to reach than most comets and its path is
predictable. |
Electronic voting machine ELECTRONIC voting machines have given a new dimension to the election process. The machine can be designed around a microprocessor chip. Some of the machines have been made by making use of TTL ICs. The important modules of the voting machine are the control unit and the ballot unit (see figure). The control unit is used by the presiding officer for “enabling” the voting machine. This process is equivalent to the issuance of a ballot paper to a voter after his credentials have been checked. The design of the ballot box unit is done in such a way that it closely resembles the existing ballot paper. The electoral names and symbols are incorporated in rectangular spaces. The desired candidate is selected by pressing a switch. The corresponding light emitting diode (LED) glows confirming to the voter that his choice has been accepted by the machine. The design of the machine is such that multiple voting is not allowed. Once enabled only one vote can be cast. The polling booth in charge can monitor the total number of votes polled during the day. The biggest advantage of
the electronic voting machine is that results can be
obtained immediately at the close of the voting schedule.
The “result enable” switch is sealed to
maintain secrecy during the voting period. Only the
presiding officer of the constituency has access to the
switch. Thus, these machines shall help in making the
election process more efficient and transparent. |
Science Quiz 1. “The scientist does not study nature because it is useful to do so. He studies it because he takes pleasure in it, and he takes pleasure in it because it is beautiful. If nature were not beautiful, it would not be worth knowing and life would not be worth living”. Name the great French mathematician, theoretical physicist and philosopher who said this about a century ago. 2. Indian and US scientists have recently launched a joint project to develop an ultra-clean fuel called DME, which will be very suitable not only for transport but also for power generation and domestic products. What is the full name of DME? 3. Artificial satellites can gather and record various types of information about the surface of the earth and oceans from a distance without actual contact with the area under investigation. What is this process called? 4. If you had an atom of antihydrogen, what would it consist of? 5. Which is the lightest metal? Who discovered it and in which year? 6. Ultrasound is a very important tool for diagnosis in medical science. To produce these waves, an alternating voltage of suitable frequency is applied to a crystal and the crystal vibrates with this frequency. What is this effect called? 7. What is the heat produced by complete burning of a unit mass of a fuel called? Name the instrument generally used to measure this heat. 8. This small animal sucks the blood of other animals for feeding itself by releasing an anticoagulant, called hirudin, at the site of bite. Name this animal that also accelerates blood circulation in the body of the host on biting and is therefore used by some people for curing certain ailments related to blood circulation. 9. The collisions between molecules in the upper atmosphere and charged particles coming from the sun cause intense beautiful displays of coloured lights mostly seen in polar regions in winter. What are these lights called? 10. A planet of our solar system and its only satellite have identical periods of rotation. Thus the position of the satellite over its planet remains fixed. Can you name the planet and its satellite? Answers |
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Satyam launches
NetVision The user can log on to Satyam Online, the Internet service from Satyam Infoway, register his account and start accessing the Net, thus eliminating the need for a personal computer (PC) completely. A 25-hour pack of NetVision is available free with the “EyeNet” settop box manufactured by the Hyderabad based Kayz Disktech (P) Ltd. EyeNet is available with a built-in modem and comes with an infra-red keyboard and a mouse function attached to it. It is priced at a little over Rs 13,000. NetVision through the EyeNet settop box would be available in Mumbai, New Delhi, Hyderabad and Ludhiana. Games management
software The integrated information management system will facilitate real time information dissemination to various bodies such as the organising committee, sports federation, media and spectators as well as facilitate the planning and allocation of resources by administrative support panel. Data recovery
software The user friendly version 7.0 is a major improvement from the previous versions, which include the power of “heuristic mode”, where the user does not have to search manually different directories and files. Added to this is support for the FAT 32 File System thereby enabling it to recover data from a very large capacity disk also. Stellar 7.0 also supports query based search operations to quickly locate data on disk. The features of the software include recovery of data from disks with corrupted/damaged partion table, boot sector, FAT and directory area; supports Windows ’98 FAT 32 File system and long file names; advanced recovery mode to perform fine tuning operations; built in file search for numerous file types; variety of different display modes and track zero bad sector. The software priced at Rs 3990 would perform in MS-DOS, Windows 95/98, Windows NT FAT based platforms. Cincom
outsourced call centres The “call centre” will establish itself as the customer relationship centre, which will also provide telephone-commerce (T-commerce) and facilitate integration of multiple information sources like phone, fax, e-mail and the web. — R.
Suryamurthy and Gaurav Choudhury |
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