SCIENCE & TECHNOLOGY
 



 

Desertification threatens one-fifth of humanity
Vishal Sharma
D
esertification sounds too trifling a problem in the world plagued by terrorism, nuclear proliferation, ethnic conflicts, Aids and other monstrosities, but this may prove to be a dangerous oversight as the phenomenon is fast engulfing vast swathes of land across the continents, affecting about a billion people.

Buildings: Repairs and waterproofing
Dr G.S. Dhillon
W
aterproofing of buildings to prevent ingress of water, involve measures which have considerably improved during recent times through research. Compounds are now available which can be used in plaster concrete. In this write-up a review of such measures has been carried out.

Unsung Edisons and Watts of India!
Mitali Mohanty Ghosh
T
heir innovations may not have the steam of a James Watt engine but they do make a difference to a few people’s lives. For Remya Jose, a schoolgirl from Palakkad in Kerala, life was easy-going till her mother fell sick.

Understanding the universe
Prof Yash Palwith Prof Yash Pal
If universe is expanding then where is it expanding?
ONE answer to your question would be that this is one of those questions that have no validity. One cannot define space without the universe. In this sense the universe expands into space that it itself creates! I know this appears confusing.

New products & discoveries

  • Under water to study outer space

  • Surgery in colonial days

  • African asses were first tamed

  • Space clothing

  • Clean power from waste coal

 
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Desertification threatens one-fifth of humanity
Vishal Sharma

Desertification sounds too trifling a problem in the world plagued by terrorism, nuclear proliferation, ethnic conflicts, Aids and other monstrosities, but this may prove to be a dangerous oversight as the phenomenon is fast engulfing vast swathes of land across the continents, affecting about a billion people.

June 17, for the past decade, is being commemorated as the World Day to Combat Desertification by the United Nations. Unfortunately, the day hardly receives any attention in India which faces a serious threat of desertification, according to the UNDP report. The report says about 12 per cent of India, stretching from the arid northwest to a broad semiarid zone from Punjab in the northwest to Tamil Nadu in the south, faces the grave possibility of desertification.

The problem is assuming alarming proportions, with the United Nation’s Food and Agriculture Organisation (FAO) warning that one-fifth of the global population stands to bear the impact of desertification spreading its tentacles across Asia, Africa, the Americas and even parts of southern Europe.

The FAO and other UN agencies estimate that 8000 to 10000 square kilometre of desert is created every year in Central Asia alone, engulfing areas where once cattle grazed and lakes existed.

A study, done by the Arid Forest Research Institute of India, on the desertification in Rajasthan, reveals that the factors responsible for the phenomenon are climatic, biotic and socio-economic. The factors include high temperatures, low rainfall, high wind velocity, overgrazing, intensive cultivation, forest removal for mining and also poverty, traditions and illiteracy of the people of the region.

Vinod Sahni, a research assistant with the AFRI, says: “The main culprit is man. The rampant deforestation and irrational cultivation patterns are intensifying the onslaught of desertification.”

The views are shared by the FAO which adds that though global warming is to be blamed, the prime responsibility remains with the mankind which is indulging into the over-exploitation of the natural resources.

Nearly two billion hectares of land, an area about the combined size of Canada and the US, is affected worldwide by human induced degradation of soils costing about $40 billion a year and affecting one billion people, says the UNDP.

In neighbouring China, sand dunes have advanced to within 100 km of the capital Beijing, forcing the Chinese to launch massive forestation measures. The darker side of the problem is that once desertification has occurred, it is almost an irreversible process.

It is high time the world community devoted its attention to a burgeoning menace which, if left unaddressed, would wreak a havoc. After all, we have only one planet to live.
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Buildings: Repairs and waterproofing
Dr G.S. Dhillon

Waterproofing of buildings to prevent ingress of water, involve measures which have considerably improved during recent times through research. Compounds are now available which can be used in plaster concrete. In this write-up a review of such measures has been carried out.

Most common use of bitumen as waterproofing measure is in the form of “felt” formed by sandwiching jute fibre or fibre glass/polypropylene mats with chemically modified bitumen. Such membranes are laid on the roofs, over a primer. There are two types of membranes in use: i) cold applied and ii) hot applied. In the case of latter, the edges are heated with flame torch, so as to make them stick to the second layer or the
overlap.

In case of flat RCC roofs, the use of felts is not so popular, firstly on account of their unaccepted black appearance. Secondly, the felts lack “breathing” capability and develop “boils” or “blisters” on account of released water vapours. Also, the use of felts prohibits the use of rooftop as terrace for social purposes.

Perhaps the most accepted use of bitumen in buildings is in the DPC (damp-proof course).

POLYURETHENE BASED TREATMENT: In this mode two liquid compounds are made use of. The base compound is polyol, which reacts with isocyanide, resulting in formation of “latex” material, which can be applied with brush to the surface to be protected to impart water-tightness. The only drawback of this mode is that when the protected surface is exposed to sunlight, the protective layer loses its strength or becomes brittle after short service life due to action of UV rays.

Epoxy resins have found many applications in civil engineering structures. The epoxy compounds have properties of rapid curing at ambient temperature, from liquid state to solid material with high strength, having good bond with normal structural materials.

The epoxy layers have low shrinkage, high resistance to chemicals, both acidic or alkaline in nature. The most significant property is that it provides high impermeability and corrosion resistance.

ACRYLIC REPAIR AGENTS: Most commonly used agent is TAPE 151 (Polysulfide) sealant which is available both for “horizontal puring” and for pressure grouting.

Perm Bond AR agent is available in the form of slurry which is applied with a brush to a cleaned and prepared surface which is to be waterproofed. While the applied material is still green and tacky, a layer of modified mortar is laid with a trowel to obtain a smooth surface which after proper curing provides an impermeable layer.

Cement grouting (pressure 3-4 kg /cm2 , slurry one cement to five parts water) has been successfully adopted for tackling leaky basements.

If repairs and waterproofing operations are carried out carefully, then it is possible to restore the structure to its original capability.
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Unsung Edisons and Watts of India!
Mitali Mohanty Ghosh

Their innovations may not have the steam of a James Watt engine but they do make a difference to a few people’s lives.

For Remya Jose, a schoolgirl from Palakkad in Kerala, life was easy-going till her mother fell sick. Apart from her studies, she now had to take up the responsibility of household chores.

A washing machine, she felt, would ease some of the burden, but was beyond the family’s means. So she designed one herself. It is a box with a rotating strainer drum and two pedals. The drum rotates as one moves the pedals, like in a bicycle. All at a cost of just Rs 1500! What’s more, it can be used to trim yourself too.

Far away in Assam, Dodhi Pathak too pedals a unique creation—a bamboo cycle!

With his family barely managing to make ends meet, a bicycle was way beyond his reach. But that did not dissuade him from aspiring to own one.

Through painstaking efforts, he put together a bicycle made of bamboo, abundantly available in his state. Barring the tyres and tubes, each part of his cycle — the valve, piston etc — was made of bamboo.

A tiny hamlet in Chikmaglur district of Karnataka tells the story of how it went from being virtually ‘’powerless’’ to becoming a village buzzing with mixer-grinders, fans, pumpsets and television sets, all thanks to a villager, G K Rathnakar. He hit upon the idea of devising a turbine light. His hydro-turbine machine generates electricity by making use of the available water and caters to the local needs.

These are unique innovations by faceless heroes, who maybe unlettered or school dropouts, unaware of their own talents, but who have made their daily lives and that of their neighbours a little better.

There are several such people ‘’but it is difficult to locate these innovators, who may have achieved their feat overcoming a lot of hurdles. Our society initially scoffs at them. They have to face financial problems too,’’ National Innovation Foundation National Coordinator (Information Technology and Dissemination), Sandeep Sharma told UNI here.

The Foundation is doing its bit to help these grassroots innovators by documenting, adding value and protecting their intellectual property rights. ‘’The NIF enables these innovators to build linkages with formal science, technological experts, convert the innovations to enterprises and pursue intellectual property rights protection,’’ said Mr Sharma.

The NIF set up by the Government of India four years ago under the chairpersonship of Dr R A Mashelkar, Director General, CSIR, helps these unsung heroes find a platform to showcase their knowledge.

With the help of its partners, the Honey Bee Networks, a voluntary organisation, and the Indian Institute of Management, Ahmedabad and various local NGOs, NIF scout for such innovations and traditional knowledge. — UNI
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Understanding the universe
with Prof Yash Pal

If universe is expanding then where is it expanding?

ONE answer to your question would be that this is one of those questions that have no validity. One cannot define space without the universe. In this sense the universe expands into space that it itself creates! I know this appears confusing. But I do not know how else to answer this. Part of the problem stems from the fact that we cannot get away from images of a three dimensional non-relativistic space.

What happens when protons and anti-protons are allowed to collide?

There was a useful imagery suggested by Paul Dirac when he gave the theory of the electron way back in 1930. It was suggested that when an electron is created a hole is left in the vacuum. This hole would behave like an antiparticle of electron. It would have a positive charge. Thus was born the concept of particles and antiparticles. Incidentally the positive electrons, later called positrons, were discovered after Dirac did his work.

Thus, given enough energy a proton and antiproton pair can also be created from vacuum. And the reverse, that when a proton and an antiproton meet their rest mass energy would be released in the form of particles of lower energy, including electromagnetic energy. Thus a proton can annihilate an antiproton producing a burst of energy. The energy released in a quiet handshake of the two would be given by the Einstein equation E = Mc^2, where M is twice the mass of a proton and c the velocity of light. All this has been completely established experimentally.

Why is it cool on hilly areas?

Let us start with the earth with an envelope of air we call the atmosphere. The atmosphere has pressure. This pressure can be considered as weight of the air column. At sea level this is a little over a kilogram per centimetre square. As we go higher there is less and less air above. This means that the pressure of the air must decrease with increasing altitude. This would imply that if I take one litre of air from sea level to an altitude where the pressure is reduced to one half that at sea level, the volume occupied by that air will become twice i.e. 2 litres. Air expands when its pressure is reduced. But we also know that when air expands it cools. If you do not know this you can check it easily by confirming that when you press the valve pin of an inflated car tyre the escaping air is cold. Also, you must have noticed that when you are pumping air into your bicycle tube the hand pump gets warmer. The reason for this is because the random energy of the air molecules is reduced when they move further apart from each other; this happens because the molecules have to work against the attractive force between the gas molecules. Thus the natural stable state of the atmosphere is one in which the temperature decreases as the pressure decreases — in other words as the altitude increases. That is why it is cold on mountains. You must also remember that air is heated primarily through contact with the ground and infrared radiation coming up from the earth surface. Little sunlight is absorbed by the atmosphere on its way down to the earth.
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New products & discoveries

Under water to study outer space

FOUR NASA crewmembers are in the deep seas to help prepare for journeys into deep space. They use an undersea laboratory to study what it may be like to live and work in other extreme environments, such as the moon and Mars.

Astronaut John Herrington lead the crew in an undersea mission July 12-21 to field-test equipment and technology for the International Space Station as part of the NASA Extreme Environment Mission Operations (NEEMO) project. Astronauts Doug Wheelock and Nick Patrick have joined Herrington, a veteran space flier and spacewalker, and biomedical engineer Tara Ruttley in the Aquarius Underwater Laboratory off the coast of Key Largo, Fla., for the mission.

Surgery in colonial days

Archaeologists combing through a dig at historic Jamestown said they have unearthed a human skull fragment that shows markings that could bear evidence of the earliest known attempts at surgery in Colonial North America.

Two marks from a saw run along the curved top edge of the 4-by-6 inch fragment, which appears to be from bone at the back and base of the skull. Three small circular markings also seem to suggest attempts were made to drill through the bone.

African asses were first tamed

African wild asses were probably tamed not once but twice in locations far apart to become the willing donkeys that carry loads the world over, an international team of researchers reported last week.

Their study of donkey DNA suggests that two separate female wild asses are the ancestors of today’s domesticated donkeys.

Space clothing

Space clothing is not so drab as it appears to be in photographs showing the “robot-like” getup of astronauts as those on the space odyssey are given a catalogue to choose their clothes, a Russian report says.

Space suits are worn only during the launch, docking, undocking and landing while rest of the time during missions, astronauts wear simple clothes, Russian news bulletin RIA Novosti SciTech Bulletin’ (the News and Technology) reports.

The report says the presence of women on space missions has made their male counterparts more careful in the selection of clothes. “Sergei Treshchev, a cosmonaut, asked for new sports shorts .... he would feel awkward wearing boxer shorts in presence of a woman,” it says.

Clean power from waste coal

A new process using methane gas and waste coal could significantly reduce greenhouse gas emissions.

This new technology being developed in Queensland (Australia) has the potential to reduce the nation’s greenhouse emissions by more than 3 per cent.

The process will provide Australian coal mines with a way to dispose of waste coal that is better for the environment and will also increase the profitability of underground mining.

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