Asian haze: threat to world climate
S. K. Bal and J. Mukherjee
FUELLED by growing population, globalisation and the Information Technology revolution, the impressive economic development has resulted in higher demands for energy, mobility and communications. The scope and magnitude of the environmental consequences of these demands are far reaching, especially with respect to air pollution in local and regional levels.

Challenges to Einstein theory
RECENT observations by scientists that the universe is accelerating and expanding all the time and that some of the supposedly fundamental constants of nature are slowly varying with time now pose challenges to the accepted general theories, including the Relativity Theory of Einstein.

EARTHQUAKE TIPS
Vertical layout of buildings
THE earthquake forces developed at different floor levels in a building need to be brought down along the height to the ground by the shortest path; any deviation or discontinuity in this load transfer path results in poor performance of the building. Buildings with vertical setbacks (like the hotel buildings with a few storeys wider than the rest) cause a sudden jump in earthquake forces at the level of discontinuity.

Flexible  subs
TEXAS A&M’s prototype unmanned underwater vehicle, being developed for the US Navy, propels itself by wiggling like a fish. Metal muscles made of alloys that remember shapes are connected to evenly spaced vertebrae and shrink and expand as much as 8 per cent as they’re alternately heated and cooled, causing the 3-foot sub’s sectional hull to bend and flex.

• A digital library

SCIENCE & TECHNOLOGY CROSSWORD

Asian haze: threat to world climate
S. K. Bal and J. Mukherjee

FUELLED by growing population, globalisation and the Information Technology revolution, the impressive economic development has resulted in higher demands for energy, mobility and communications. The scope and magnitude of the environmental consequences of these demands are far reaching, especially with respect to air pollution in local and regional levels. In most cases unsustainable development practices are being blamed for a number of environmental disasters, including extreme drought condition in Africa, flooding in Czech republic and unprecedented melting of polar ice. This phenomenon can be linked to infamous London smog of the past caused by coal burning and the petrochemical smog of Los Angeles.

This discovery of the so-called Asian haze by INDOEX (Indian Ocean Experiment) scientists is a clear evidence of the magnitude of the problem. As though we did not have enough to worry about the weather, what with global warming, the ozone hole, and the new El Nino season, UN scientists have now identified this new threat to the world climate. This report by UNEP (United Nations Environment Project) about the haze has created a lot of hue and cry in this subcontinent. Though a lot of controversy has arisen regarding the haze, residents in cities know by their stinging eyes and itchy noses that pollution has been building up for several years.

This haze is a vast cloud of smog, a 3-km thick brownish layer, hovering over most of the tropical Indian Ocean, south, southeast and east Asia - a soup of industrial pollutants; carbon monoxide from vehicles exhaust and particles from burning forests and millions of rural cooking fires. The haze consists of sulphates, nitrates, organics, black carbon, and flyash amongst several other damaging airborne pollutants. A large part of the aerosol clouds come from the inefficient cookers, where fuels such as cowdung and kerosene are used to cook food in rural areas. Air pollution near cities would be even much larger with contributions both from biomass burning and fossil fuel combustion. With accelerating urbanisation and high population growth rate, mega city air pollution is assured to become a major problem of the future in the Asia Pacific region.

• Significant reduction in the solar radiation reaching the surface. Pollutants scatter and absorb incoming solar radiation and thus reduce up to 10% of solar energy reaching the ocean and 10-20% over land surface thus cooling the land and water while adding significant heating to the atmosphere. It will also increase the solar heating of the lower atmosphere by 50-100% and decrease the temperature of the land surface.

• The reduction in radiation could result in alterations of spatial gradients of atmospheric temperatures ultimately shifting the monsoon precipitation system, drying out the northern and northwest sector of South Asia while increasing rainfall over the oceans. This phenomenon appears to have altered the region’s monsoon rainfall pattern - increasing rainfall and flooding in Bangladesh, Nepal and N-E India while cutting back needed seasonal precipitation in Pakistan and N-W India.

• The haze could have potential impacts on agriculture by impeding plant growth and vitality due to ozone and deposition of pollutants, decrease in surface irradiance availability for photosynthesis and alteration of winter monsoon hydrological cycle. During the entire wheat season in India, the available rainfall is between 25-150 mm and can be affected due to changes in regional hydrological cycle caused by aerosols. Thus wheat crop yield in this part of the earth could be vulnerable to the haze. The pollution may also cut India’s winter rice production by 10%.

• In the biggest ever study of the phenomenon scientists warned that the haze is responsible for hundred of thousands of death a year from for respiratory diseases and appears to be increasing along with the pollution in densely populated South Asia.

• Not only the haze cuts sunlight, heating the atmosphere, but also creates acid rain, a serious threat to crops and trees, as well as contaminating water resources and hurting agriculture.

• It is unclear what the haze’s relationship is to global warning, which most scientists believe is caused by emission of greenhouse gases that trap the earth’s heat.

• Increase in the frequency and strength of thermal inversion that traps more pollution, which will aggravate the situation in future.

• Some studies reveal that this haze is transferred far beyond the source region, particularly during dry season. While many scientists once thought that only lighter greenhouse gases (GHG), such as carbon dioxide; could travel across the earth, they now say that aerosols can too.

The scientists of the USA and Europe have termed this haze as "Asian Brown Cloud" which is not appropriate. The scourge of pollution is by no means restricted to the Asian region. Man-made aerosol pollutants are rampant in Europe and the USA. "Biomass burning" from forest fires, vegetation clearing and fossil fuel was just as much to blame for the shrouding haze as dirty industries from Asia’s great cities. A lot of blame is laid at our continent. Instead of blaming developing countries for the pollution of the planet, everybody should work towards advocating international agreements to control pollution.

Constructive interaction between science and policy makers at the working level is the need of the time for the better management of the environment, as for ensuring the sustainability of the economic development of the region without a serious threat of environment degradation.

Action must include phasing out fossil fuels and replacing them with clean renewable energy and tough laws to protect world’s forest.

As far as agriculture is concerned scientists should look at possible genetic remedies, taking advantage of CO2 increase but hardy to atmospheric pollution and drought.

Great improvement had been made in developed countries either by strict emission controls or by switching from coal to natural gas, and similar steps would have to be taken in developing countries to prevent the pollution getting out of hand.

It is too early to draw definite conclusions about the impact of the cloud, and of similar hazes over some parts of Asia. More research is needed, but the initial findings by some scientists clearly indicate that this growing cocktail of soot, particles, aerosols and other pollutants are becoming a major environmental hazard for Asia. Scientists and policy makers should avoid making premature final assessments but should start trying to cut pollution by introducing more efficient heating stoves in developing countries and turning to solar power and other clean sources of energy. The Brown cloud does not recognise borders, and it indiscriminately hurts people, in their health and in their livelihood, wherever they live. If we want to address issues of agriculture, health and water, then we have to address energy. We simply have no other choice but to shift to energy sources that will not harm our air, but allows pursuing economic growth.

The writers are from the Department of Agronomy and Agrometeorology Punjab Agricultural University, Ludhiana.

Challenges to Einstein theory

RECENT observations by scientists that the universe is accelerating and expanding all the time and that some of the supposedly fundamental constants of nature are slowly varying with time now pose challenges to the accepted general theories, including the Relativity Theory of Einstein.

These challenges could lead to dramatic rethinking and reformulation of the theories of universe and elementary particles, according to Dr B. G. Sidharth, Director-General of the Hyderabad-based B. M. Birla Science Centre.

He says that when Einstein proposed his general theory of relativity some 85 years ago, the accepted picture of the universe was one where all major constituents were stationery. This, he said, had puzzled Einstein because the gravitational pull of these constituents should make the universe collapse.

So Einstein introduced his famous cosmological constant, essentially a repulsive force that would counterbalance the attractive gravitational force, he added.

Shortly thereafter, according to Dr Sidharth, there were two dramatic discoveries which completely altered that picture.

The first was due to astronomer Edwin Hubble, who discovered that the basic constituents or building blocks of the universe are not stars, but rather huge conglomeration of stars called galaxies and the second discovery was the fact that these galaxies are rushing away from each other.

There was no need for counterbalancing cosmic repulsion any more and Einstein dismissed this as his greatest blunder.

Dr Sidharth said over the next 40 odd years, these observations evolved into the Big Bang theory according to which all the matter in the universe possibly some 15 billion years ago was concentrated in a speck at the birth of the universe which was characterised by an inconceivable explosion or bang. This led to the matter being flung onwards, and that has what kept the galaxies rushing outwards even today.

In the mid 1960’s confirmation for the Big Bang mode of the universe came from the detection of a cosmic footprint. The energy of the initial Big Bang would still today be available in the form of cosmic microwaves, which accidentally were discovered.

Over the next three decades and more, the Big Bang theory was refined further and further. An important question was whether the universe would continue to expand for ever, though slowing down, or whether the expansion would halt one day and the universe collapse back again.

Much depended on the material content or density of the universe. If there was enough matter, the expansion would halt and reverse. If not the universe would expand for ever.

However, the observed material content of the universe appeared to be insufficient to halt the expansion. This and a few other intriguing observations led astronomers to invoke dark matter, that is matter which is present in the universe, but which nevertheless is not being detected.

With this thrown in, it appeared that the universe had sufficient matter to halt the expansion.

Dr Sidharth said there still were several subtler problems to be addressed. One was the famous horizon problem. To put it simply the Big Bang was an uncontrolled or random event and so different parts of the universe in different directions need not be the same, just as people in different parts of the world need not wear the same type of dress.

Observations, however, showed that the universe was by and large uniform, like people in different countries wearing the same dress. UNI

EARTHQUAKE TIPS
Vertical layout of buildings

THE earthquake forces developed at different floor levels in a building need to be brought down along the height to the ground by the shortest path; any deviation or discontinuity in this load transfer path results in poor performance of the building. Buildings with vertical setbacks (like the hotel buildings with a few storeys wider than the rest) cause a sudden jump in earthquake forces at the level of discontinuity (Figure 3a). Buildings that have fewer columns or walls in a particular storey or with unusually tall storey (Figure 3b), tend to damage or collapse which is initiated in that storey. Many buildings with an open ground storey intended for parking collapsed or were severely damaged in Gujarat during the 2001 Bhuj earthquake.

Buildings on sloppy ground have unequal height columns along the slope, which causes ill effects like twisting and damage in shorter columns (Figure 3c). Buildings with columns that hang or float on beams at an intermediate storey and do not go all the way to the foundation, have discontinuities in the load transfer path (Figure 3d). Some buildings have reinforced concrete walls to carry the earthquake loads to the foundation. Buildings, in which these walls do not go all the way to the ground but stop at an upper level, are liable to get severely damaged during earthquakes.

Adjacency of Buildings

When two buildings are too close to each other, they may pound on each other during strong shaking. With increase in building height, this collision can be a greater problem. When building heights do not match (Figure 4), the roof of the shorter building may pound at the mid-height of the column of the taller one; this can be very dangerous.

Figure 4: Pounding can occur between adjoining buildings due to horizontal vibrations of the two buildings.

Flexible subs

TEXAS A&M’s prototype unmanned underwater vehicle, being developed for the US Navy, propels itself by wiggling like a fish. Metal muscles made of alloys that remember shapes are connected to evenly spaced vertebrae and shrink and expand as much as 8 per cent as they’re alternately heated and cooled, causing the 3-foot sub’s sectional hull to bend and flex. The result: No ripple evidence on the surface of the sub’s presence, making it much quieter then today’s vessels.

A production version of the sub, at least three years off, could be as long as 13 feet and would be used for underwater reconnaissance (such as explosives detection) or exploration (ocean mapping). Popular Science

A digital library

The Massachusetts Institute of Technology is adding to its online offerings an electronic library for the already vast and mounting catalogue of scholarly materials born in digital form.

The digital library, called dspace, initially will be managed by a federation of eight universities, including MIT. It will be available on the world wide web and enable data to be stored not just in text but in video and other formats.

The system runs on “open source” software that was developed in conjunction with Hewlett Packard Company. That means other institutions can use or adapt the program royalty-free to create digital libraries of their own that could easily be linked to the dspace consortium.

“The average lifespan of a digital document is only a few years,” said Ann Wolpert, director of MIT’s libraries. “So the goal here is to create the capability, the persistence in works that are born digitally.”

Over the next few months, the seven other universities will come online, officials said. They include England’s Cambridge as well as Columbia, Cornell, Ohio State, and the universities of Rochester, Toronto and Washington state.

After an initial testing period of about a year, it is hoped the number of universities involved would expand.

MIT is also working to make the system interconnect with the university of California’s eScholarship program, a digital library launched in July 2000 that holds more than 1,200 titles, including books and articles.

The system was built to be almost indefinitely expandable, Wolpert said. AP

SCIENCE & TECHNOLOGY CROSSWORD

23. Dwarf breed of dog with broad flat nose and wrinkled face.

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