118 years of trust
Chandigarh, Thursday, September 24, 1998
 

Landslides in Himalayan region
By Shirish Joshi
SOME news items appear regularly in certain months of the year. For example, floods in the months of July and August, cyclones along the West coast in May and June and along the East coast in October and November. Landslides in Himalayan hills in monsoon months are also one of them.

Turbocharging an engine
By Manjeet Singh
THE most efficient method of measuring the power of an engine is by supercharging i.e. increasing the flow of air into the engine to enable more fuel to be burnt.

Severe quakes after 2030
Part of North-east India will witness high-magnitude earthquakes between 2030 and 2040, says a study.

Biodegradable plastics
SCIENTISTS have used a combination of distillery waste and microorganisms to make way for a low cost method of producing biodegradable plastics.


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Landslides in Himalayan region
By Shirish Joshi

SOME news items appear regularly in certain months of the year. For example, floods in the months of July and August, cyclones along the West coast in May and June and along the East coast in October and November. Landslides in Himalayan hills in monsoon months are also one of them.

However, this year the loss of human lives due to landslides was rather heavy. One landslide in July near Rudraprayag in Uttar Pradesh took the lives of 69 tourists. This was followed by landslides near Malpa village along the Kailash Mansarovar route. The number of pilgrims and villagers who lost their lives is not known accurately but may run in a few hundreds.

What is a landslide? A landslide in Himalayas looks like an avalanche of debris. The mass of earth starts flowing down like a slurry all of a sudden under the influence of gravity, and buries the houses and people who happen to be along the route.

According to the scientists working at the landslide control division of the Wadia Institute of Himalayan Geology (WIHG), landslides are generally caused by the weight of a mass of soil that moves along a sliding surface. Heavy rainfall or a cloudburst as it occurred in the current monsoons provides the lubricating material to the top soil and force of gravity does the rest.

Why do the occur most in Himalayas? Himalayan region is more prone to landslides because of its geological conditions. According to geologists Himalayas are very young, only about 45 million years old. Compared to them, the mountains in South India are very old.

The theory of plate tectonics believes that the continents as well as the seas and oceans which form the crust of Earth are in continuous but very slow motion. The top crust is not a single shell of granite and basalt, but a mosaic of several rigid segments, called plates. These plates with an average thickness of 100 km float on the denser fluid mantle below called Asthenosphere.

When the supercontinent of Pangaea broke up some 250 million years ago, the Indo-Australian Plate on which India lies began to drift northwards. It moved quickly in geological time scale and about 45 million years ago, hit the larger and heavier Eurasian Plate, giving rise to Himalayas. The floor of the ancient Tethys Ocean which had separated the two plates was forced upwards and created the Himalayan range of mountains which extends from northern Assam in the east to Nanga Parbat in the west.

Movement along the plate boundary is still going on resulting in minor and major earthquakes. Over the last 1.5 million years, Himalayas have grown 1370 m higher. Eventually the two plates will become one by fusing together. But today they are still moving, and continue to push the Himalayas even higher. Mount Everest is growing in height by a few millimetres a year. Nowhere on earth are there peaks like Himalayas. Nine of the world’s 14 highest peaks, more than 8 km in height, including Everest, lie there.

A convincing proof is provided by fossil of fish and other marine life found in Himalayas. They are a strong evidence of the fact that the rocks that comprise them originated as marine deposits between 65 million and 570 million years ago, when they formed the floor of the ancient Tethys Ocean.

Landslides are a serious problem in Himalayas and a lesser problem in other areas of India. They block roads, silt up rivers and ravage vast stretches of agriculture land along the slopes of hills. When they occur at night they destroy villages and bury alive hundreds of people sleeping in the homes.

Massive debris from landslides sometime block the river flow to create temporary lakes. When the water manages to burst through the blockade, it unleashes highly destructive floods, wiping out villages on river banks in the lower region.

Can we prevent landslides by taking protective measures? The Central Soil and Water Conservation Research and Training Institute at Dehradun in Uttar Pradesh has developed a technique to show that even the worst landslide-prone areas can be made harmless. The technique has been demonstrated in a chronic landslide prone area on the Dehradun-Mussoorie road.

The flash flow of torrential rain carrying debris from steep slopes has been checked by a judicious combination of engineering and forestry measures. But to carry out such measures in Himalayas requires Himalayan effort and vast resources.

There is a need to evolve a multi-disciplinary approach to tackle the problem. To start with landslide inventory maps should be prepared with the help of remote sensing technology to study in depth the mechanism of landslides. Areas most prone to landslides and the circumstances which trigger the landslides in particular spots should be studied in depth and identified.

Based on the above data a landslide warning system can be evolved on the basis of bed rock formation, geological characteristics, hydrological conditions and water content in the soil. The loss of human life and property could be thus averted to a great extent. Developmental activities like constructing roads and building houses should be undertaken in harmony with environment and only in areas declared safe by geologists and engineers. People should be kept away from the areas falling under sites most prone to landslides.

Can they occur elsewhere in India? Landslides are not very common along the Western Ghats, which are made of basaltic rocks. With an average height of only 1,200 m, they are about 1,600 km long and run along the western border of the Deccan Plateau. With a large rock becomes loose due to washing away of the binding soil due to erosion caused by torrential rains, it falls down causing a rock to fall. Rock falls block roads and destroy every thing along their route.

Are human beings responsible for landslides? Yes, to a great extent. Environmentalists like Sundarlal Bahuguna well-known for his opposition to Tehri dam and Chandi Prasad Bhatt of Chipko movement attribute the increasing menace of landslides in Himalayas to heavy soil erosion caused by the loss of forest cover in the Himalayas. Unless the wide-scale unchecked deforestation in the area is stopped and vegetation in the hills is protected, the number of landslides that occur every year will continue to increase.

They also suggested that earth-binding plants could help limit landslides. A change in the pattern of land use and construction activities is necessary. In the words of Dr V.C. Thakur, Director of WIHG, “Unless these measures are taken on a war footing, the situation would continue to remain grim.”

The world’s worst landslide occurred in Gansu province of China on December 16, 1920. The landslide triggered by a single earthquake killed an estimated 180,000 people. This is about 25,000 more than the people killed at Hiroshima on August 6, 1945, where the first nuclear weapon was used.Top


 

Turbocharging an engine
By Manjeet Singh

THE most efficient method of measuring the power of an engine is by supercharging i.e. increasing the flow of air into the engine to enable more fuel to be burnt. It can be done by compressing the air charge prior to admission to the cylinder to a pressure higher than atmospheric, thus increasing the wt. of air in the cylinder for the combustion of the fuel. The compressor thus needed is either directly driven by the engine or by the otherwise waste exhaust gas energy.

The former involving a reduction in useful power output of the engine alongwith additional manufacturing complications, servicing and repair. The use of exhaust gas energy to drive a turbine which in turn is mounted on a compressor is a more constructive approach. The compressed air is thus delivered to the cylinder. Hence a higher power output can be delivered from a same sized engine or the size and weight of engine can be reduced for the same power output.

The specific fuel consumption (SFC) decreases considerably. This unit constituting of the turbine, turbine housing, shaft, shaft housing, compressor and the compressor housing is called “turbocharger” and the method is called “turbocharging”.

Now a days the turbocharger is finding wide applications in combine harvesters, tractors and other similar internal combustion (IC) engines in India. Now engines have a turbocharger fitted as original equipment or many retrofit kits are also available. In turbocharged engines the inlet and exhaust valve timings are made to overlap at idle top dead centre, probably by about 120 so that an appreciable proportion of charge air passes straight to exhaust where it serves to cool the exhaust valve and reduce the temperature of the gases reaching the turbine, normally limited by the manufacturer to about 650C.

The scavenge air naturally cools the exhaust valve but plays little or no part in cooling either the piston or the cylinder head during the passage from inlet to exhaust. Under supercharged conditions the cooling of both these components is critical. The volume of fuel injected must be increased to gain significant power increases as a result by installing a turbocharger but a saving in SFC usually results due to better stochiometric ratios (since the compressed and denser air contains up to 50% more oxygen). This leads to improved combustion efficiencies.

Axial flow and radial type turbochargers are mostly used for the IC engines. The turbocharger units appear simple but are manufactured to very fine engineering tolerances. They attain high speeds of revolution (typically 20,000-40,000 rpm) with rotor blade tip travelling at around 60 m/s. Adequate lubrication is essential at the bearing surface. Lack of lubricant most commonly occurs when starting or stopping the engine, which can lead to bearing failure, seal damage etc.

Idling for at least 30 seconds when starting up is normally recommended to enable oil flow to be fully established before increasing engine speed. Since the engine lubricating oil is subjected to high temperature as it passes through the turbocharger the correct oil must be used as specified for turbocharger engines.

Turbocharger engine provides many advantages over the naturally aspirated engine like large increase of power output from an engine of existing cylinder swept volume, reduction of fuel consumption at the levels due to improved efficiency, reduction in engine length by approx 20 to 40% reduced maintenance costs due to the fact that it is easier to maintain the smaller turbocharger engine than the larger naturally aspirated engine.

The writer is Assistant Professor, Agricultural Engineering, PAU, Ludhiana.
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Severe quakes after 2030

Part of North-east India will witness high-magnitude earthquakes between 2030 and 2040, says a study.

Using an artificial neural network (ANN) to analyse the statistics on the seismicity of the region for the last 200 years, researchers from the University of Roorkee say the Arakan Yoma and Naga thrust belt in North-east India will experience quakes of high magnitude after 2030.

The area, lying between 20 degrees N and 27.5 degrees N latitude and 93 degrees E and 98 degrees E longitude, will be less affected by high-magnitude quakes till 2025 when it will be in an energy accumulation state. After that quake activity will start showing till 2030, with release of energy, the researchers report in the journal Current Science.

The third stage, called the “intense release of energy state” will start from 2030 and continue for 10 years when the area, which is part of the Indo-Burmese seismic region, will witness high magnitude earthquakes, they have found.

The seismic activity of this region is a consequence of collision tectionics in the Himalayas and the subduction tectonics (plunging of one plate under another) below the Burmese plate and is associated with a few major geological units, the report says. (PTI)Top


 

Biodegradable plastics

SCIENTISTS have used a combination of distillery waste and microorganisms to make way for a low cost method of producing biodegradable plastics.

The simple technology, which is awaiting transfer to industries, can easily substitute petrochemical-based industrial polymers whose non-degradable property makes their disposal difficult, says National Environmental Engineering Research Institute (NEER) in Nagpur which developed it.

While earlier technologies for producing ecofriendly polymers like polyhydroxybutyrate copolyhydroxyvalerate (PHB/PHBV) were hindered by the high cost of production, the new technology offered by NEERI scientists is a viable option.

The properties of PHBs are comparable to commonly used bulk plastics like polypropylene in terms of water resistance, flexibility, toughness and can be easily moulded into films, fibres and sheets, the report said.

By using cheap sources like distillery wastes and whey as substrates, the cost of production can be scaled down from Rs 950 per kilogram to Rs 140 per kg, it said.

The NEERI scientists screened 25 different microorganisms which were capable of producing PHBs, and came up with three most promising ones — Methylobacterium, Azotobacter and Alcaligens.

The chemical process perfected by scientists yields product that is 97 per cent pure, the report added. (PTI).
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Science Quiz
By J.P. Garg

1. Which rare animal, now an endangered species, does China plan to clone using technology much more complex than that used by other countries till now?

2. GPS is a satellite based radio navigation system which guides a person/vehicle about the shortest distance and direction of location where the person/vehicle wants to reach but has lost the track. What does GPS stand for?

3. Carbohydrates are essential ingredients of our food. Which chemical elements are contained in carbohydrates?

4. What is the approximate length of blood veins in human body?

5. Which acid is there in our stomach?

6. Which trees representing the Hindu Trinity of Brahma, Vishnu and Mahesh give out oxygen during night time unlike other trees which give out carbondioxide during night?

7. How many galaxies are roughly there in the whole universe? On the average, how many stars are estimated in a galaxy?

8. These low-cost conducting materials have the properties of both metals (like electrical conductivity) and those of plastics (like light weight, resistance to chemical changes). What are these materials commonly known as?

9. Name the first satellite launched by India. What was its date of launching? Which rocket carried it in space?

ANSWERS

1. Giant Panda 2. Global positioning System 3. Carbon, hydrogen and oxygen 4. About 10,000 kilometre 5. Hydrochloric acid 6. Bargad ‘pipal’ and ‘gular’ 7. 100 billion (one kharab); 100 billion (one kharab) 8 Synthetic metals 9. Aryabhata; April 19, 1975, USSR Intercosmos rocket.

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  NEW PRODUCTS & DISCOVERIES

 

Voyager goes on and on

On February 15, Voyager 1 became the most distant human-made object in the solar system. Launched on September 5, 1977, the spacecraft flew by and snapped images of Jupiter and Saturn.

Voyager 1 is now carrying out its secondary task, the Voyager Interstellar Mission, surpassing even the distance record of Pioneer 10, which is five years older. Voyager 1 will continue to push toward the heliopause, the invisible boundary that separates our solar system from interstellar space and represents the outermost edge of the sun’s magnetic field. With five major scientific instruments still collecting data, scientists will continue to receive information not only about the heliopause, but also about interplanetary magnetic fields and the speed of charged particles in the solar wind. With the spacecraft so far away, however, radioed data takes more than nine hours to reach earth.

By the year 2003, Voyager 1 will pass through “termination shock” on its way to the edge of the solar system. Scientists are hopeful that the spacecraft will reach the actual heliopause — thought to be about three or four times as far away as Pluto — before the year 2020, when the craft’s electric power runs out. (Popular Science)

For a better detergent

After more than 20 years of endeavour, a new starch derivative is set to make its way into detergent formulations worldwide.

The new chemical, a derivative of maltidextrin, will replace the existing detergent co-builderzeolite polycarboxylate combination.

Co-builders are required to soften water and to sequester dirt and grease from the fabric.

The advantages of the new starch-based cobuilder over synthetic polycarboxylates are its naturalness, degradability and low environmental impact, reports Manufacturing Chemist.

Although polycarboxylates have excellent properties, the major disadvantage of these cobuilders is non-biodegradabilitly. But the new material, developed by scientists from the pharma and chemical division of Cerester Application Centre, Belgium, is able to meet the green demand.

Washing trials have proved that the maltodextrin derivatives achieve the adequate detergency performance. Biodegradability and a number of toxicological tests, including acqueous toxicity, oral toxicity and irritation potential were also performed. Results show that the starch cobuilder meets the industrial standards and consumer health requirements.

New microbe to clear oil fields

Scientists at the Institute of Microbial Technology (IMTECH) in Chandigarh have identified a new microbe which converts hazardous hydrocarbons into harmless substances.

The microbe, originally found in the oilfields of Gujarat, is capable of degrading polycyclic aromatic hydrocarbons (PAHs) like napthalene and phenanthracene since it uses these hazardous compounds as its source of carbon and energy, according to the IMTECH’s latest annual report.

In a four-year project the IMTECH team led by Rakesh Jain identified and characterised the new microbial strain called Moraxella species.

PAHs like napthalene and phenanthracene are known to cause cancer and are enlisted by the US Environmental Protection Agency (EPA) as priority pollutants.Top


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