SCIENCE & TECHNOLOGY


Harnessing of Indian rivers

R.N. Malik
R
IVERS have played a pivotal role in building Indian economy because they provide two basic inputs i.e. irrigation water and very cheap hydro power. Nature has been extremely bountiful in providing good rainfall and big river basins in India. Now it is left to the ingenuity of Indian people to harness these rivers to the hilt and strengthen the economy further.

Alien message “in our DNA’’
F
ORGET waiting for ET to call — the most likely place to find an alien message is in our DNA, according to an expert in Australia.

Secret to seduction
C
ASANOVAS may be born to woo while cavemen cannot control their wandering hands, according to research by a team of American scientists.

Prof Yash Pal

Prof Yash Pal

UNDERSTANDING THE UNIVERSE
WITH PROF YASH PAL
We know that the energy of the sun is due to the fusion of hydrogen nuclei to form helium nuclei, which requires very high temperature. From where did the sun get the energy to attain that temperature initially when fusion started?

New products & discoveries
Nanotube filter

Bridging the gap between the nanoworld and the macroworld, researchers have created a membrane out of carbon nanotubes and demonstrated its potential for filtering petroleum and treating contaminated drinking water.


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Harnessing of Indian rivers
R.N. Malik

RIVERS have played a pivotal role in building Indian economy because they provide two basic inputs i.e. irrigation water and very cheap hydro power. Nature has been extremely bountiful in providing good rainfall and big river basins in India. Now it is left to the ingenuity of Indian people to harness these rivers to the hilt and strengthen the economy further.

Soon after Independence, the country constructed multipurpose storage and hyrdro-power projects e.g. Bhakra, Pong, Nagararjunsagar, Krishnasagar, Rihand, Hirakund, Gandhisagar, Ramganga projects etc. But somehow the attention of the Power Ministry shifted towards construction of super thermal power plants. Therefore, only a few storage dams like Narmada (600 MW), Tehri (1400 MW) and Indrasagar (900 MW) could see the light of the day during the last 40 years. Now the Government is hesitant to take up big projects because of two negative factors i.e. rehabilitation of oustees and resistance of powerful environment lobbies. The result is that 70 per cent of the run-off is still wastefully flowing down the sea and vast tracks of arid land are suffering for want of irrigation water. India has 10 major river basins which drain the run-off to the sea annually.

There are other medium and small basins like Sabarmati, Mahi and Sabaranrekha which carry an annual flow of 25.00 bm3 with a power generation of 3000 MW.

A thorough study of these basins highlights following facts.

* The Brahamputra River carries the maximum annual flow of 510.00 bm3. Good rainfall in the entire basins round the year requires minimum canal irrigation. Minimum flow is as high as 1.5 lakh cusecs and therefore ideal for power development at 80 per cent load factor. Flood control is a big problem as the valley is narrow.

* In case of the Ganga basin, three rivers i.e. Ghagra (102), Gundak(59) and Kosi (59), carry 40 per cent of the total flows and cause heavy floods in eastern U.P. and Bihar. These rivers originate in Nepal territory and no storage project could be taken up so far. The Ganges and Yamuna carry a flow of 150.00 bm3 at Allahabad. Tehri and other projects have a storage of 14.0 bm3 and 100.00 bm3 of water goes to sea unutilised.

* After the Ganga, Mahanadi and Godavari rivers provide the maximum scope for water harvesting. These two rivers have an annual flow of 172.00 bm3. Hirakund and other projects create a storage of 23.00 bm3 and 100.00 bm3 of water still goes to sea unutilised.

* The Krishna river has been harnessed a lot. The total storage created by different dams is 30.00 bm3 and only 18 bm3 goes to sea.

* Mahanadi, Godavari, Krishna and Cavery rivers provide the ideal scope for interlinking through gravity flow along the east coast to provide great relief to arid lands in respective states.

At Present 60 per cent area of Rajasthan, M.P., Chhattisgarh, Andhra Pradesh, Karnataka, Orissa and Tamil Nadu suffers from drought conditions. Therefore we need to construct storage dams across various rivers to withhold rainfall run-off during the rainy season. In case of the Yamuna and Ganga (50 bm3 up to Tajewala and Hardwar), we have to construct big dams (600 feet and above) in Uttaranchal State as valley storage is minimum and big pondage area like Gobindsagar is simply not available. But the hills in M.P., Rajasthan, Jharkhand and Western Ghat are of low height. Number of earthen dams of low height and long base will store the required amount of water and tame 80 per cent of the flow in rivers like the Gomati, Ken, Betwa, Son, Mahi, Tapi, Mahanadi, Godavari, Krishna and Cauvery. The Government of India must frame a time-bound programme to create additional storage of 150 bm3 in next 10 years. Incidentally, this storage will give a power generation of 10000 MW.

The performance in harnessing of Indian rivers for power development is equally depressing. Storage dam of big reservoir capacity of 7- 9 bm3 are constructed near the foothills as wide storage space is available there only. In higher reaches it is difficult to get live storage capacity of even 1 bm3 with a dam height of 200 metres. Hence power projects in the upper reaches have to be set up in a cascading manner to run as run- off-the-river schemes. Such projects run at full capacity only during the monsoon season and 25 per cent capacity during the remaining nine months of the year. The power load factor is therefore only 45 per cent. The cost of construction of such projects is Rs 6 crore per MW while the equivalent cost at 100 per cent load factor comes to Rs 13.0 crore per MW (more than solar energy development project). The only way to increase the power load factor of successive downstream projects is to build one big storage project in the uppermost regions whose live storage capacity is at least 1bm3 capacity. This mother dam will retain the silt at the source and protect the downstream projects from this chronic problem.

The writer is a retired Engineer-in-Chief

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Alien message “in our DNA’’ 

FORGET waiting for ET to call — the most likely place to find an alien message is in our DNA, according to an expert in Australia.

Professor Paul Davies, from the Australian Centre for Astrobiology at Macquarie University in Sydney, believes a cosmic greeting card could have been left in every human cell.

The coded message would only be discovered once the human race had the technology to read and understand it.

Writing in New Scientist magazine, Davies said the idea should be considered seriously.

For more than 40 years astronomers have been sweeping the skies with radio telescopes hoping to catch a signal from an alien civilisation.

So far the search has been in vain. But Davies believes it is wrong to assume that extraterrestrials who may be hundreds of millions of years ahead of us technologically will have chosen to communicate by radio. Leaving artefacts for humans to find once they are sufficiently evolved — like the obelisk in the movie ‘’2001: A Space Odyssey’’ — might be a more attractive strategy, he said.

But ensuring the survival of such an artefact over possibly millions of years would be difficult. A better solution would be to incorporate information into the human genome, allowing it to be copied and maintained over immense periods of time. — DPA

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Secret to seduction

CASANOVAS may be born to woo while cavemen cannot control their wandering hands, according to research by a team of American scientists.

Which one you are may depend on a ‘’courtship circuit’’ in the brain that scientists have identified in fruit flies.

They believe a similar mechanism might influence the basic process of seduction in humans.

The male fruit fly goes through a complex ritual when trying to attract a mate. In strict order, he senses and follows the female, taps her with his foreleg, ‘’sings’’ by vibrating his wings, and finally touches her genitalia with his proboscis.

Only after this sequence is copulation attempted.

But scientists found that the five steps to fruit fly heaven go out of the window when 60 specific nerve cells in the insect’s brain are not working properly. Prof Bruce Baker, from Stanford University in California, said: ‘’When we interfere with the functioning of those 60 cells, the male essentially skips the tapping step and attempts to do everything else at once.

‘’He tries to copulate, lick her genitalia and play her a love song simultaneously. So what normally takes a total of four minutes is reduced to just 10 seconds - and that doesn’t work very well. ‘’The clumsy efforts of male fruit flies behaving badly sound all too familiar.

And it might be no coincidence. Baker pointed out: ‘’The fruit fly is a model organism whose basic cellular functions are very similar to what they are in people. — DPA

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UNDERSTANDING THE UNIVERSE
WITH PROF YASH PAL

We know that the energy of the sun is due to the fusion of hydrogen nuclei to form helium nuclei, which requires very high temperature. From where did the sun get the energy to attain that temperature initially when fusion started?

You are right in saying that the energy of sun is produced through fusion. Fusion can occur only if the colliding nuclei have enough energy to overcome the electrical repulsion between like charges. This energy can be provided through thermal energy of nuclei at high temperature. Your curiosity is about the mechanism through which this high temperature is obtained in the first instance. The argument goes as follows:

Stars are formed through condensation of large clouds of gas and dust. This condensation is due to mutual gravitational attraction. What you require is a small in non-homogeneous region that has more than the average density. This results in a greater attraction to that region. That which is slightly bigger keeps on getting bigger — very much like the rich getting richer. There is a deep consequence. In falling together gravitational energy gets converted to kinetic energy of particles. These particles collide with other particles that are falling in. Motions get chaotic. That is heat; therefore the temperature rises. If the mass that accretes together is large enough, like that of our sun or other stars, the release of energy can raise the internal temperature to millions of degrees. Higher the accreting mass, greater is the release of gravitational energy and higher the internal temperature. Higher the internal temperature greater is the rate at which the fusion of hydrogen takes place and hotter the star. There is a paradoxical consequence of this phenomenon. Larger stars consume their fuel in such a profligate manner that they might live only for a few million years, while our sun will continue for at least another five billion years. The big ones do not last long. They die earlier than the smaller ones. But let me step back a little to illuminate this discussion further.

The question of stability of the stellar furnace has to be understood. How does our sun continue shining with the same intensity? There is no computer control, nor any operator. The reason is simple and elegant. The start of fusion reactions in a collapsing cloud produces energy and increases the internal pressure. When this pressure equals the gravitational pressure of contraction the star becomes stable. Any decrease in the rate of energy production would decrease the internal temperature and hence the pressure. This would lead to a contraction of the star and hence an increase in temperature and pressure to restore stability. Similarly an increase in temperature would increase internal pressure, leading to an expansion of the star and hence internal cooling. Sometimes it is said that Jupiter is a star that did not quite make it because it was not big enough. It still produces more energy than it receives from the sun! This energy comes, perhaps, from continuous descent of helium under the force of gravity inside the core of Jupiter. Gravity is a very weak force as compared to the electrical and nuclear forces. However, its influence dominates because it has the same sign for all forms of matter and energy.

If there is an explosion some distance away from a building why the broken glass from the windows is usually found outside the building and not inside?

Even though I have not seen any buildings destroyed by explosions I tend to agree with the observation. I do not know why. I have gone through literature and there is a mention of the effect of a nuclear explosion far away in which a large plate glass window of a department store had fallen outside the building. There was a case of a newly built multistory skyscraper in Boston; the building swayed due to strong winds and the large window glasses started to rain outside the building. They had to find a clever way of fitting the building with a large pendulum inside to reduce the swaying and the problem was corrected. What does all this tell me about the reason for the observation - presumably correct - you have made? I am no expert but I will make some guesses. When the pressure wave of the explosion strikes a building, the whole building shakes. The pressure impact is not confined to the glass surface. When strong plate glass windows are fixed in the openings of the building it is quite possible that slightest relative bending or twisting of the building would snap the mounting system and the heavy glass plate would fall down. The forward movement of the window and the building is partly in unison. In other words the inside of the building is also moving inside-ward, along with the glass.

Another thought might have a bearing. A thick and large glass plate can also bend a little on impact of a pressure wave. This bending might also cause a separation of the window fasteners, resulting a separation of the window and the building. I confess that what I have said might be plausible and yet wrong. The analysis is complicated and I have not gone through it.

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New products & discoveries
Nanotube filter

Bridging the gap between the nanoworld and the macroworld, researchers have created a membrane out of carbon nanotubes and demonstrated its potential for filtering petroleum and treating contaminated drinking water.

Scientists have long valued carbon nanotubes for their high strength and thermal properties, yet it’s been a challenge to assemble nanotubes into useful materials large enough for people to hold in their hands.

Researchers at Rensselaer Polytechnic Institute in Troy, N.Y., and Banaras Hindu University in Varanasi, have now devised a method for making such large-scale structures and found an application for them.

Intelligent glass

Soaring airconditioning bills or suffering in the sweltering heat could soon be a thing of the past, thanks to University College London chemists.

Reporting in the Journal of Materials Chemistry, researchers reveal they have developed an intelligent window coating that, when applied to the glass of buildings or cars, reflects the sun’s heat so you don’t get too hot under the collar.

While conventional tints block both heat and light the coating, which is made from a derivative of vanadium dioxide, allows visible wavelengths of light through at all times but reflects infrared light when temperature rise over 29 degrees Celsius. Wavelengths of light in this region of the spectrum cause heating so blocking infrared reduces unwanted rays from the sun.

The coating’s ability to switch between absorbing and reflecting light means occupants benefit from the sun’s heat in cooler conditions but when temperatures soar room heating is reduced by up to 50 per cent.

No, backpacks do not hurt

Backpacks have gotten a bad rap. For years, specialists have urged school children to lighten their loads, wear their backpacks on both shoulders and avoid lugging around those heavy school bags whenever possible. But new research from a University of Michigan Health System physiatrist indicates backpacks don’t cause the stress and strain on young backs that they’ve been linked to.

“There is no good scientific evidence to support the claim that schoolbag load is a contributing factor to the development of low back pain in growing children,” says Andrew Haig, M.D., medical director of the U-M Spine Program and associate professor of Physical Medicine and Rehabilitation and of Surgery at the U-M Medical School.

Designer mice

By tweaking a gene in the mouse genome, scientists are creating animal models of Huntington’s disease that mimic human Huntington’s and may lead to effective treatments for this killer illness.

“I am heartened by this research, because when I started out in this area maybe 25 years ago, we really didn’t have any agents to try in patients. Now, if you look down the list, we have 15 to 20 different agents that we can eventually test in humans,” said Dr M. Flint Beal, The Anne Parrish Titzell Professor of Neurology and Chairman of Neurology and Neuroscience at Weill Cornell Medical College, in New York City. Dr. Beal is also Neurologist-in-Chief at NewYork-Presbyterian Hospital/Weill Cornell Medical Center.

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