SCIENCE TRIBUNE Thursday, December 27, 2001, Chandigarh, India
 


Magnetic levitation for transportation
S.S. Verma
A
ir flights are and will remain beyond the reach of a major section of society, particularly in India. Moreover there are problems of wastage of time in air traffic delays and growing safety concerns. Trends in increased mobility of large masses with changing lifestyle for more comfort are leading to congestion on roads with automobiles. Besides, increasing pollution levels from automobiles, depleting fuel resources, critical dependence on the fuel import and due to a limited range of mobility of buses and cars the need for fast and reliable transportation is increasing throughout the world.

NEW PRODUCTS & DISCOVERIES
Using steam for cleaning
I
f cleaning things such as the garbage can, the oven or the shower curtain were such a joy, there would be no problem, and all your cleaning would be done easily, and effectively. Steam Buggy is a revolutionary cleaning solution that lets you clean every room in your house with just ordinary water!

  • Cost-saving waste water filtration
  • Pipe joining made quick and easy

SCIENCE QUIZ
J. P. Garg tests your IQ

   
 
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Magnetic levitation for transportation
S.S. Verma

Air flights are and will remain beyond the reach of a major section of society, particularly in India. Moreover there are problems of wastage of time in air traffic delays and growing safety concerns. Trends in increased mobility of large masses with changing lifestyle for more comfort are leading to congestion on roads with automobiles. Besides, increasing pollution levels from automobiles, depleting fuel resources, critical dependence on the fuel import and due to a limited range of mobility of buses and cars the need for fast and reliable transportation is increasing throughout the world. High-speed rail has been the solution for many countries. Trains are fast, comfortable, and energy-efficient and magnetic levitation may be an even better solution.

Further expansion of various transport systems is leading to all sorts of problems. It is believed that conventional railroad technology has reached its peak performance. Though, a few high-speed conventional trains (at speeds up to 300 Km/h) are operating successfully in developed countries but further development and use of such trains in general and in developing and under developed countries in particular is not as promising as they were once thought to be. Therefore, it appears that the future of high-speed ground transportation belongs to magnetically levitated (maglev) vehicles which "fly" just above a guideway (i.e., railway track) making "magnetic flight" a reality. Therefore, in a time of crisis related to the transport systems regarding their role in pollution and wastage of energy sources, there is a great need to develop transportation systems based on magnetic levitation.

Development of magnetic levitated transport systems is under progress in developed countries and it is just a matter of time they make inroads to India as well. Therefore, it will be interesting to know about the science and technology behind mass ground transport system known as "magnetic flight".

In 1907, Robert Goddard, a student, later known as "father of modern rocketry" published a story describing the features of a maglev transportation system. In 1912, a French engineer named Emile Bachlet proposed a magnetically levitated vehicle. Because of the large power consumption involved in the system, however, the proposal of maglev was not taken seriously and the idea lay more or less dormant for half a century. In 1963, J.R. Powell, an American Physicist suggested using supreconducting (superconductor means no resistance or zero electrical resistivity) magnets to levitate a train over a supreconducting guideway. Further developments in science and technology then made possible a system using less expensive conducting guideway at room temperature. Maglev research and development began in Germany and Japan during the early 1970s. The purpose of the initiative was to evaluate possible improvements for intercity transportation with magnetic levitation. The tasks included "planning, analysing, and assessing maglev technology" to make it a viable option for future transportation. Significant effort has been devoted to the understanding of maglev’s technical and market potential.

Magnetic levitation for transportation involves support and guidance (propulsion and braking) of objects or vehicles by the use of magnets. Magnetic levitation is based on the principle that when a magnet moves over a conductor it induces eddy currents in the conductor. According to Lenz’s law these eddy currents flow in a direction that opposes the changing magnetic filed due to the moving magnet. The magnets provide support without contact or friction, allowing for fast, quiet operation. In a typical system, the vehicle, which resembles a railroad car, travels above a guideway. Arrays of magnets of like polarity in both the vehicle and guideway reply each other, producing the lifting force. By continuously changing the polarity in alternate magnets, a series of magnetic attractions and repulsions created that moves the vehicle along the track. The electrical energy required for such a system is great and the use of superconducting materials offers the only realistic potential for this means of transportation.

Magnetic flight can make use of either Electro Magnetic Systems EMSs (based on attractive forces) or Electro Dynamic Systems EDSs (based on reclusive forces) systems or a combination of them to levitate the vehicle. Initially the research and development were directed towards both electromagnetic and electrodynamic systems but in recent years only electromagnetic have seriously been considered. Full scale maglev vehicles have been tested in many developed countries and efforts are going on to make these systems public.

Besides the speed improvements over other methods of transportation, maglev trains have many benefits at slower speeds too. The different advantages being associated with magnetically levitated trains in comparison to conventional trains is as summarized below.

Power & Cost benefits

* Unlike conventional transportation systems in which a vehicle has to carry the total power needed for the most demanding sections, the power of the maglev motor is dependent on the local conditions such as flat or uphill grades.

* Power is only supplied to sections where a vehicle is currently located. This method conserves energy and prevents safety concerns because all vehicles in a section of track must be travelling at the same speed in the same direction.

* Maglev uses 30% less energy than a high-speed train travelling at the same speed (1/3 more power for the same amount of energy).

* Specific energy consumption is less than all other comparable means of transportation.

* Maglev trains experience much faster acceleration without affecting passenger comfort.

* The operating costs of a maglev system are approximately half that of conventional long-distance railroads.

* Energy consumption is lower per seat than other comparable means of transportation and faster turnaround times mean fewer vehicles and operating staff are required.

* The cost of making the guideway is a high percentage of the total investment for a maglev system. These costs are no higher than those of other high-speed rail system and the comparison looks even better for maglev when the terrain becomes difficult. Many of the tunnels, embankments, and cuttings necessary for roads and railroads are avoided because maglev guideways can be easily adapted to the topography.

Safety benefits

* Research has shown that the maglev is about 20 times safer than airplanes, 250 times safer than conventional railroads, and 700 times safer than automobile travel.

* Despite the speeds up to 500 km/hour, passengers can move about freely in the vehicles at all times.

* Maglev vehicle carries no fuel to increase fire hazard

* The materials used to construct maglev vehicles are non-combustible, poor transmitters of heat, and able to withstand fire penetration.

* In the unlikely event that a fire and power loss occurred simultaneously, the vehicle is automatically slowed down so that it stops at a predefined emergency power station.

* Maglev vehicles cannot be derailed because they surround the guideway.

* A collision between two maglev trains is nearly impossible because the linear induction motors prevent trains running in opposite directions or different speeds within the same power section.

* There is no solution against all vandalism and sabotage. However many precautions have been taken.

Versatile utility

* The guideway, or track, that the maglev trains run on can be raised above the ground or be at ground level. This flexibility plus the ability for substantially sharper turns and steeper grades than railroads allow maglev guideways to be located in many different conditions.

* As with conventional railroads, trains are made up of several individual vehicles coupled together. This enables trains to be constructed depending upon demand and the frequency increased when needed.

* Neither the number of seats per section nor the number of sections comprising a train affects the performance of a maglev train.

* The high speeds of a maglev system make it suitable for transporting urgent goods with container sections. These container sections can form their own trains or be coupled with passenger sections to form "mixed-traffic" trains.

* Maglev research is investigating the possibility of exclusive passenger routes and exclusive freight routes.

* Even with much faster journey times, comfort was a key consideration during maglev development. There are no jolts during acceleration, braking, or passing at any speed.

* Extensive measurements, computer models, and experience from high-speed rail have resulted in an advanced technology for keeping the vehicles pressure-tight.

* A major advantage of conventional rail systems versus other methods of transportation is their ability to operate in almost all weather conditions. Maglev systems are even better prepared for icy conditions because they do not require overhead power lines nor pantographs — parts that are subject to freezing on conventional railroads.

* The guidance and propulsion components are mounted below the guideway where they are protected from ice and driving snow.

* Snow will rarely accumulate on the guideway because of the frequency of trains and the wind. Moreover, the gap between the bottom of the vehicle and the top of the guideway allows operations even if snow builds up on the guideway.

* Because of their advantages, maglev trains are planned for three areas of transportation: local connections such as airport links; medium-distance inter-city connections; and long-distance national and international connections.

* Maglev routes will be grouped with existing transportation wherever possible.

Environmental friendliness

* Maglev trains are more environmentally — friendly than alternative forms of transportation.

* Noise is reduced by the contactless technology used.

* There is no friction because of the contactless technology, resulting in very little mechanical wear.

* Air pollution is reduced because of no emissions of exhaust gasses.

* Less land is required for both the ground-level and elevated guideway and leaves the ground beneath the elevated guideway suitable for other purposes such as agriculture and traffic.

* In areas utilising a ground-level guideway, there is still enough clearance for small animals and microorganisms to pass underneath so there will be little effect on the environment.

* The maglev guideway construction also eliminates animal collisions that frequently occur with roadways.

* Unlike conventional railroads, a maglev guideway does not dissect the landscape. The landscape requires fewer changes and does not have to be free of all natural growth as they do for conventional railroads.

* Maglev trains release no pollution into the ground they run above nor do they affect local water.

* A well-developed construction plan will result in less damaging effects during construction than during that of conventional railroads and roads.

* Maglev releases an extremely low magnetic field. The magnetic field, even inside a passenger compartment, is considerably less than that of a hair dryer, toaster, or electric sewing machine. It will therefore have no negative influence on cardiac pacemakers or magnetic cards such as credit cards.

Germany is the furthest into their development efforts and closet to beginning construction of a commercial maglev route. The German maglev train is expected to begin operation over the 292-km route in 2005. While America appears to be many years from the first maglev demonstration, the practical form of high-speed transportation will soon be a reality in Germany and Japan, which will set the stage for new maglev development projects around the world.
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NEW PRODUCTS & DISCOVERIES
Using steam for cleaning

If cleaning things such as the garbage can, the oven or the shower curtain were such a joy, there would be no problem, and all your cleaning would be done easily, and effectively. Steam Buggy is a revolutionary cleaning solution that lets you clean every room in your house with just ordinary water!

You can use the Steam Buggy to clean and sanitise kitchen counter tops, sinks and even loosen the most stubborn burnt on, greasy mess in your oven with ease. With no fumes, no chemicals and no scrubbing, cleaning has never been easier. Lightweight and portable, the Steam Buggy allows you to steam away mold and mildew on bathroom tiles, soap scum from faucets and even all those hard to reach areas. And it’s so easy to use! Simply fill with water, turn it on and point the nozzle at the area you want to clean. Then wipe the area clean. There are no costly professionals to pay, and with the handy floor attachment, you can use the steam to penetrate deep into carpet, loosening and dissolving dirt and stains. The pressurised steam also eliminates harmful allergens and bacteria below the surface. The Steam Buggy can clean virtually any mess you can create, claim the manufacturers.

For varying degrees of cleaning power there’s the high pressure steam jet nozzle that can be used on grills and even the wheels of your car to blast away dirt and grime. It also comes with an upholstery brush, a floor attachment for your carpet or rugs, a window cleaner to clean your windows with just one swipe, terry cloth cover and a measuring cup. Retails for about $ 150.

Cost-saving waste water filtration

Researchers have developed rotating membrane filters for waste water filtration as alternatives to presently used pumps that are powered by electricity, thus promising a reduction in costs.

In the present system, the waste water in sewage plants passes horizontally over the filter, so that the sludge deposited on the filter can only reach a certain depth and any further solids are swept away by the current.

From time to time the filter has to be cleaned. Besides, the system has another drawback — the pressure causing the liquid to flow at the required rate is generated by pumps which consume expensive electricity. Thus, more the waste water, higher are the costs.

But a promising new development — rotating membrane filters developed by scientists at the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB is Stuttgart — can reduce cost by between 80 and 90 per cent, a report in Fraunhofer Gesellschaft said. PTI

Pipe joining made quick and easy

An innovative pipe-joining technology with huge international commercial potential has been developed by researchers and has simplified conventional pipe-fitting processes across the industry.

Oyster Converter — developed by Osytertec Plc, a small United Kingdom Company — allows the joining of two pipes without the need for soldering, gluing, welding, screwing or compression.

Moreover, the process takes up to 70 per cent less time to complete using only a spanner and a pair of modified pliers, a report in British Commercial News said. PTI
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SCIENCE QUIZ
J. P. Garg tests your IQ

1. Born in 1836, this British lady became a legend by being the first woman doctor licenced to practice in Britain, when medicine for women was a taboo. Can you name this courageous physician who cured thousands of poor and ailing women and children at that time?

2. The fastest growing plant is bamboo. How high can it grow in 24 hours?

3. Previously only humans and apes were known to recognise their own reflections in a mirror. Now scientists have found that a water animal also spends time in looking at its own image in a mirror. Which is this animal?

4. These beautiful birds are sometimes mistaken for nightingales because of the songs they often sing at night. Both males and females of the species sing. They build their nests quickly and almost anywhere and are known for being aggressive defenders of their territories. Which are these birds that are associated with Christmas due to their red breasts?

5. Zoologists of a college in Bikaner have recently been successful in regenerating the lens of eyes in mammals like tadpoles, mice and guinea pigs. In your view, which vitamin can be helpful for such regeneration, which can result in far reaching benefits for lakhs of blind in our country?

6. Which constellation contains "Jewel Box" that looks like a beautiful showpiece but actually is an open cluster of a variety of different - coloured stars?

7. It has been observed that there is loss of bone material among astronauts while they are weightless in space. Can you think of the possible reason for this phenomenon?

8. What is the study called in which the various forces acting on bodies and their consequent motion is taken into consideration?

9. In one type of photosynthesis reaction, called light reaction, solar energy is absorbed by chlorophyll and converted into chemical energy. What is the other type of photosynthesis reaction called and what happens in this reaction?

10. The Delhi centre of CEERI has recently designed a wheel chair the movements of which can be easily controlled by the user by speaking. What is the full name of CEERI and where are its headquarters?

Answers
1. Alizabeth Garret Anderson 2. About one metre 3. Dolphin 4. Robins 5. Vitamin A 6. Crux, also called Southern cross 7. Without strength building activity, bones cannot absorb calcium from the diet 8. Dynamics 9. Dark reaction, in which carbon dioxide is converted into glucose 10. Central Electronics Engineering Research Institute, Pilani (Rajasthan).
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