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| SCIENCE TRIBUNE | Thursday, June 8, 2000, Chandigarh, India |
Living in balance with water by Pravin Kumar ON May 18, 2000, Mumbai received 140 mm rainfall, which is nearly three-fourths of what the Thar Desert in Rajasthan receives in a whole year, on an average. Not since 1951 has the city received such a heavy downpour. This only shows how greatly skewed over space and time is the distribution of water, a substance vital for all biological processes. New petrol-electric hybrid cars Science
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Living in balance with water ON May 18, 2000, Mumbai received 140 mm rainfall, which is nearly three-fourths of what the Thar Desert in Rajasthan receives in a whole year, on an average. Not since 1951 has the city received such a heavy downpour. This only shows how greatly skewed over space and time is the distribution of water, a substance vital for all biological processes. The average rainfall in India (1,200 mm annually) is considered fairly heavy, but the bulk of it (70 per cent) is spread over a 100-day span, beginning on or about June 1 and lasting till mid-September. During the rainy season, all the rain falls in about 200 hours, and one-half of it in 20 to 30 hours. Most of the rainfall is in the form of heavy downpours, resulting in floods and soil run-offs. While some areas in Rajasthan receive less than 200 mm rainfall annually, several places in North-East India get as much as 11,000 mm. There is no place which receives less than 100 mm annually, even this is sufficient to meet local drinking water needs, if harvested properly where it falls. A rule of thumb is that the number of hours of rain that a place receives in a year is equal to the quantity of rain, in centimetres, that it receives annually. Thus, Delhi with an annual rainfall of 80 cm receives this in just 80 hours — something which Edward Lutyens evidently did not take into acccount when he planned New Delhi. He probably assumed that the 80 cm rain was spread evenly over 365 days, for the road which connects the old city to New Delhi, dipping below the Minto Bridge, is invariably water-logged after a downpour of 20 to 30 mm. On the face of it, water is a plentiful substance. The total volume of water on earth is some 1,360 million cubic kilometres, enough to cover the globe to a height of 2.7 kilometres, if spread evenly. Of this, more than 97 per cent is seawater, 2 per cent is locked in the icecaps and glaciers, and a large portion of the remaining 1 per cent is underground and unusable. In India, various states have run-ins over the sharing of the river waters. Maharashtra, Karnataka and Andhra Pradesh are haggling over the height of the Almatty dam over the Krishna river. Kerala and Tamil Nadu are deadlocked over the Mulai-Periyar dam at the confluence of the Mullaiyar and the Periyar rivers. In 1991, there were riots in Karnataka over the sharing of the Kaveri waters with Tamil Nadu. According to conflict analysts, disputes over water could increase dramatically during the next century. “The competition between countryside and cities for available water supplies intensifies”, warns Lester Brown, president of the Washington-based World Watch Institute. Metropolitan cities in India are already short of water: Chennai and Bangalore receive water on alternate days. Chennai has yet to receive the promised water from the Krishna river from Andhra Pradesh. A pointer to climate change is the first observable melting of the earth’s ice-cover, including the Himalayas, since record-keeping began — according to a new study by the World Watch Institute, the Washington-based think-tank. This means that the glacier-fed rivers of north India would first swell and then shrink to dangerously low levels. An estimated 50 million people who already live in this region of severe water-scarcity depend on the glacier-fed Indus and Ganga for drinking water and irrigation. Models suggest that India might get more water due to the global warming, but the additional rain could take the form of more intense monsoon. Most of the water would then run off in damaging floods rather than augmenting soil moisture and stable supplies. All this uncertainty makes it difficult for farmers, water utilities and engineers to know how to plan for the future and what kind of investment to make. Thus, as the earth warms up, there is likely to be mismatch between the need for water and the ability to minister to that need. Closely linked to climate change and water scarcity is food production. At the present rate of population growth, India will be short of almost 45 million tonnes of grain to feed her population in 2030. The Green Revolution missed out on the unirrigated areas, which make up 80 per cent of the cropped area and from which increases in food production will have to come. One hope is that the low-per acre yield in India leaves scope for being stepped up. In the 20th century, mega dams became a short-cut to step up farm yields. Irrigation dams permit 40 per cent of the world’s food to be raised on just 16 per cent of the cropped land. All over the world, large hydro-power dams have proved counter-productive. All of India’s dams with a capacity greater than one cubic kilometre are fast filling up with sediment. There is a big question mark over the Narmada project, now stalled by court and environmentalist actions. In the US, there is now a dam decommissioning industry, which is concerned with restoring the free flow of rivers. In India, dams were promoted by the British to maximise the land-revenue collection. Water-guzzling crops like sugarcane, which brought in more revenue, were encouraged. Today, sugarcane occupies 2.5 per cent of the cultivated area in Maharashtra but consumes 60 per cent of the irrigation water. Since India’s Independence, about Rs 50,000 crores have been spent on surface irrigation projects. The cost of large schemes (allowing for inflation) has more than doubled between 1950 and 1980. About 50 per cent of the total irrigation potential is estimated to be still untapped. Eighty per cent of Indian villages still lack a reliable supply of drinking water. “What successive governments have been promoting”, concludes Dying Wisdom, a study by the Centre for Science and Environment, New Delhi, “is a combination of large-scale surface water systems, planned and managed by unaccountable bureaucracies, and numerous small, privately-managed wells operating within minimum state or community-imposed constraints... The beneficiaries of this ‘policy’ have been, in the case of large surface-systems, irrigation departments, contractors, politicians and large farmers, and, in the case of wells, large farmers and those in charge of subsidy programmes. The losers have been members of community-based organisations...” Losing out to groundwater Canal irrigation is losing out to groundwater irrigation through bore-wells, which are about twice as efficient as the former. However, groundwater has been exploited without giving thought to replenishing the underground aquifers (rock or soil layers bearing water) by means of water and soil conservation measures to hasten the downward percolation of water. In Maharashtra, the Groundwater Regulation Act (1994) remains a dead-letter in the statute book, because when it was sought to be implemented, there were widespread riots in the state. Groundwater is a free-for-all. In Nasik district, the bore-wells dug by rich sugarcane farmers have lowered the water-table so greatly that the surface wells of small farmers go dry in summer. There is no all-India law governing the use of groundwater. Groundwater is a resource only if it is properly husbanded — not merely exploited as it is today in India. It is not a give-away. In nature, it is re-charged by precipitation and run-off, but this balance is upset when the amount of water pumped out exceeds the natural re-charge. Prof. P.R. Pisharoty, one of India’s leading meteorologists, warns that India is mining groundwater which may be about 7,000 years old. In West Bengal and Bangladesh, the excessive use of groundwater contaminated with arsenic for drinking has caused arsenical dermatitis in the population — a disease affecting the hair, nails and skin. Eight districts of West Bengal with a population of 38 million are reported to be thus affected, according to a report in the journal Current Science. In Bangladesh, 95 per cent of he domestic water supply schemes run on underground water; Dhaka is the only city in the world which meets 95 per cent of its water requirements from underground sources. All the indications are that increasing competition for scarce water, along with environmental concerns, will siphon water away from agriculture. Not only will new irrigation projects be harder to build, but some irrigated lands will lose water in order to restore degraded systems and to deliver water to growing cities. As freshwater supplies for agriculture dwindle, farmers will have to grow water-efficient and salt-and drought-resistant crop varieties. Studies reveal that wheat is a good candidate for breeding in greater tolerance to salt, which could allow this important cereal to remain productive on salinised lands. There is no escaping from pricing water more realistically if we want to conserve this limited resource. The global expereince has been that whenever water consumption has been taxed, there has been a fall in tha demand for water. Rural consumers have a marked dislike for paying water tax — even three paise per litre. Water charges are fixed on the basis of the size of farmers’ plots and the crops grown. They are so low (2 to 5 per cent of the harvest) that they have no influence on farmers’ management decisions, which typically are based on the government’s support price policy.
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New petrol-electric hybrid cars Scientists at Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia are developing two new petrol-electric hybrid cars with only half the fuel consumption and ten per cent of the emissions of existing vehicles. Both the cars will use advanced technologies like electric motors, batteries and energy management systems develped by CSIRO and some Australian car component making companies. The cars are expected to be completed by the mid of this year, according to a report in Ascent Technology Magazine. The first will demonstrate parallel hybrid technology which, either automatically or under the driver’s control, switches between the electric motor or the petrol motor to drive the wheels. The second will demonstrate series hybrid technology, whereby only the electric motor directly drives the wheels, with the petrol motor being turned on and off as needed to recharge batteries and super-capacitors. In both the cases the power for acceleration and energy from braking will come from and go to the super-capacitors. The cars would not be funny little vehicles, but medium-sized vehicles with attractive and exciting looks, and would have the same performance as that of current cars, the researchers say. They will, however, be more efficient and much less polluting. They are expected to reduce fuel consumption by half, and emissions by 90 per cent. The electric motor is based on ‘‘reluctance’’ — the tendency of iron to get attracted to a magnetic field. The ‘‘switched reluctance’’ motor works by energising a number of coils, typically 12, around the motor. Electricity is switched to different patterns of coils as the rotor moves. In recent years, advances in computers and power electronics have allowed the switching to be done electronically. The motors are cheap — as low as 100 US dollars in mass production — because they do not require either a winding on the rotor or permanent magnets. They are robust too, have a wide power range (a gearbox is not needed) and can be made into generators by reversing and switching, thus putting power back into the batteries when the brake is applied. While some hybrid cars use expensive nickel metal hydride batteries, CSIRO has beefed up the familiar, and relatively cheap, lead acid battery. Patented improvements developed over the past decade give CSIRO the edge with batteries that are lighter and much quicker to charge, taking only a few minutes, instead of hour. The batteries require little maintenance and last longer. The purer lead moderates problems of hydrogen gassing, making it easier to keep battery cells in sound health’’. Conventional capacitors in radios, electric motors and electric power systems store small amounts of electricity for very short periods of time. By using CSIRO technology, an Australian company. Cap-XX Pty Limited has developed commercial supercapacitors which store thousands of times more energy. The ‘‘supercap’’ delivers the energy in times useful for power hungry devices serving mobile phones, wireless devices, notebook computers hybrid vehicles. The cars can accelerate from 0 to 100 kilometres per hour in 8-10 seconds using 100 chocolate-block-sized supercaps in a suitcase-size package. They can then be recharged more quickly by braking. The interplay between the batteries, supercapacitors, generator, motor and engine will be managed by a sophisticated on-board computer. A unique internal combustion engine, developed by CMC Power Systems in Australia, will provide power for the batteries and supercapacitors through a generator. About 40 per cent smaller and lighter than conventional engines, the CMC engine has extremely low noise and vibration, lower fuel consumption and lower emissions. |
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Science
Quiz 1. The British chemist Sir Humphry Davy is credited for his invention of miner’s safety lamp. But while Davy was still experimenting, another British inventor and engineer designed and made an equally good version of this type of lamp. When ultimately Davy built and publicised his lamp, there was a fierce controversy as to who deserved credit for the invention. Can you name the scientist who missed the credit? 2. Continuing on the subject, can you name the invention for which this British engineer was given credit officially? Can you also name his son who further developed his father’s work? 3. This nitro compound is prepared by the nitration of phenol and was used as an explosive in World War I. Now it is normally used in the manufacture of dyes and pigments, and as an antiseptic in the treatment of burns. Which is this acid? 4. Name the instrument which is generally used in ships, tanks and submarines to view over or around an obstacle. Which type of simple optical devices are used in this instrument? 5. This vitamin, having chemical name biotin, is needed for healthy skin and circulatory system. What is the alphabetical name of this vitamin which is made in the body by bacteria? Who discovered it and in which year? 6. Name the process which is the basis of physical growth in plants and animals and in which the quality and number of chromosomes remain unchanged. 7. If we look at the stars in the sky throughout the night, the positions of the stars appear to change with the passage of time. What is the cause for this apparent shift in the positions of the stars? 8. PSZ is a high-tech ceramic used for making fire bricks, crucibles, high-speed machancial components, automobile engine parts, etc. What does PSZ stand for? 9. We know that iodine is added to salt to ensure normal working of the thyroid gland. Which compound of iodine is generally used for this purpose? 10. OFSMS is a new system of monitoring the strains within materials and has wide applications in medical technology, civil engineering, study of structures of aircrafts and ships, etc. What is the full form of OFSMS in which optical fibres can be embedded within the structure to make such a study? Answers 1. George Stephenson 2. Locomotive (railways); Robert Stephenson 3. Picric acid 4. Periscope; mirrors/prisms 5. Vitamin H; Hungarian biochemist Albert-Szent Gyorgi and US biochemist Vincent Du Vigneaued in 1940 6. Mitosis 7. Rotation of the earth about its axis 8. Partially stabilised zirconia 9. Potassium iodate 10. Optical Fibre Strain Monitoring System. |
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New products & discoveries ‘‘Here I Am’’ card The card announces locations by playing a tune when exposed to light. The 83mm long, 53mm wide, 3mm thick card features an integrated circuit, light sensor and a battery with a life span of 2 to 3 years. The Here I Am card is easily stuck onto a wallet, passport, credit card or other article to keep labs on its location. A tune, chosen from a selection of over 20 songs ranging from ‘‘Ave Maria’’ to ‘‘Yankee Doodle’’, begins to play when the sensor is exposed to light and stops when replaced in the darkness of a pocket, briefcase or whatever. The invention is extremely valuable if a wallet falls, or is taken by theft, from a pocket, as the music sounds immediately. Company President Hiroshi Majima of the Tokyo-based Majima Company, says he hit on this idea when a friend lost his passport during a trip to China. Three ‘‘Here I Am’’ cards are seen here being displayed; one stuck to the front cover of an airline ticket, one inserted into a man’s wallet, and a third being held in the hand itself. Nortel Networks
solutions As part of this relationship, IBM will establish a global consulting practice dedicated to deploying Nortel Networks Clarify e-business application, including Clarify e-Front Office, the first fully integrated CRM and e-Business suite that empowers customers to interact with companies on their own terms via the medium of their choice. Citrix internet
solution MySAP.com is the internet solution that connects employees, customers, suppliers and business partners as if all were one company. Citrix MetaFrame can be used to provide access to any Window-based application from mySAP.com workplace. Videocom video
on the net Video-on-the-net accelerates business access to state-of-the-art web-based videoconferencing, eliminating the barrier-to-entry requirement for investment in expensive hardware and software. The service enables companies to host multi-user videoconferences using high-speed IP networks. The ASP service empowers organisation to harness applications that take full advantage of the broadband IP revolution. It also provides a wide range of IP-based interactive communication solution, including live multi-point videoconferencing, video-streaming and broadcasts, video-on-demand, data-sharing, voice-over-IP and access to corporate Intranets. Organisation will be able to book, schedule and deliver a robust range of interactive solutions using a browser. BSE trading
network With this new network, the BSE has a sophisticated platform for introducing new trading services and products. The Network supports emerging web and other high speed technologies and allows the BSE to implement a comprehensive disaster recovery plan. Cisco core
service — R. Suryamurthy and |
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