Innovative European lunar probe
by Radhakrishna Rao
THE 14 nation European Space Agency, which has an active and significant space science programme, has initiated a programme called “Euromoon 2000” which would involve the launch of a lightweight lunar orbiting satellite in the year 2000.

Hazards of noise pollution
by Rohit Malik
MODERN life given rise to a new form of pollution i.e. noise pollution. Noise is rapidly becoming the most widespread environmental pollutant. No doubt, noise is a normal phenomenon of life but it is continuously disturbing human peace and tranquillity.

Science Quiz

Saving earth from UV radiations
by Parveen Parkash

HUMAN brain with a capacity of around 1400cc has altered the environment according to his comforts and needs. In doing so, he has endangered the whole life- supporting system. One such glaring example of over- indulgence with the supporting system is consistent depletion of the protective shield which absorbs deadly radiations of the sun - the ozone layer. As a result, today we find ourselves engulfed by the dangers of UV radiations. Some depletion of the ozone layer may also be happening on account of a natural phenomenon.

But the chief manmade cause is the production of deterrent chemicals. These chemicals which endanger the ozone layer today were earlier considered “miraculous” substances, useful to consumers and industry and harmless to human beings and the environment. From their invention in late 1920s, the use of these chemicals became widespread, especially after world war II. In the early 1970s concern began to be expressed that the ozone layer might be vulnerable to these chemicals clubbed under the title of halocarbons, i.e. compounds containing chlorine, fluorine, bromine, carbon and hydrogen. Chlorofluorocarbons (CFCs) are stable and non-toxic, cheap to produce, easy to store and highly verstile. These compounds proved immensely useful for refrigeration, air conditioning, blowing foams, hair and perfume sprays, cleaning computer circuit board and as solvents, sterilates and aerosol propellants.

World production of CFCs remained concentrated largely in the USA and Western Europe, doubled after every five years since 1930s. Chlorofluoro carbons CFC13 and CF2C12 commonly known as “freons” have been used most widely since 1930. As per the estimate of 1986, the world consumption of CFCs and halons works out to be around 1.2 million tonnes per year.

As the scientific knowledge advanced, other families of chemicals have also been identified as ozone depleters. These include: (i) Halons or bromofluorocarbons (BFCs), which are similar to CFCs in structure but contain bromine rather than chlorine. These are mainly used as fire extinguishing agents and are more dangerous to the ozone layer than CFCs. (ii) Hydrochlorofluorocarbons (HCFCs), have been developed as alternatives to CFCs, and are used in refrigerators and aerosol sprays. These are less destructive to ozone layer. (iii) Methylchloroform and carbon tetrachloride are used as solvents mainly for cleaning metals during engineering and manufacturing operations. Methyl bromide is used as an agricultural pesticide fumigant. These compounds also cause depletion of ozone layer and are covered under Montreal protocol.

Ozone hole was first observed in 1979 in Antartica (south pole). The area of this hole is increasing steadily every year and now it covers South Australia and New Zealand too. The record of the Antartic ozone holes of 1992 and 1993 has shown that ozone completely disappeared at altitudes of 14 km to 19 km in the month of October during these years. It is believed that particles from volecanic eruption at Mount Pinatubo in 1991 accelerated ozone destruction. The 1995 ozone hole lasted longest, although it was neither the deepest nor the largest on record. It covered an area greater than 10 million km 2 (roughly equivalent to the surface area of Europe) for 77 days, compared to 63 days in 1993 and just 25 days in 1985. The ozone depletion over India was noticed 10 years ago when it was about 6% and now the level has gone up to 8%. The reports of experts from about 28 countries show that the ozone layer is now depleting at a much faster rate than before. India ranked 12th among the nations causing destruction of ozone layer. The United States contributes about 30% of depletion and ranked first. Japan has ranked second, Britain third and China eighth. Throughout the 1970s scientists began to suspect and then detect an increased thinning of the ozone layer. This thinning has resulted in continuous rise in the amount of UV-B reaching the earth’s surface which in turn has harmful effects on human health, animals, plants, microorganisms, materials and air quality:

UV radiations affect the genetic material, i.e. DNA (Deoxyribonucleic acid). DNA disorders may lead to mutation, genetic defects and even cancer.

In humans, long-term exposure to UV-B is associated with the rist of eye damage: a 1% increase in stratospheric ozone depletion is estimated to result in 0.6%-0.8% rise in the incidence of cataracts, which results in 100,000-150,000 additional cases worldwide.

UV rediations can cause suppression of immune system, which is a potentially serious problem in areas where infectious diseases are common.

The study conducted in an ozone chamber on hairless mice, commonly used for skin research in the university of California, Berkeley, has concluded that ozone rapidly strips vitamin E from the uppermost layer of skin. Vitamin E is a fat soluble vitamin found in some plant oils and leaves of green vegetables. It protects human skin. The findings of this study have helped in explaining why urban living can aggravate skin ailments such as dermatitis, which results in itchy, red, inflamed and scaly skin.

In light-skinned population, high exposure to UV radiations is the key risk factor in the development of skin cancer: experiments suggest that cases increase by 2% for every 1% reduction in stratospheric ozone.

Marine life is particularly vulnerable to UV-B. This is a matter of serious concern as more than 3% of the world’s animal protein for human consumption comes from sea. UV-B damages the early development stages of fish, shrimp, craband other water life and reduces the productivity of phytoplankton, the foundation of the acquatic food chain. Hence it lowers sea productivity thereby depleting the oxygen concentration of marine water. These primary factors adversely affect the marine flora and fauna.

Plant growth may be reduced by UV-B radiations, which harms crop yields and quality and damages forests. In turn, reductions in the productivity of marine and terrestrial ecosystems can reduce the uptake of carbon dioxide and contribute to global warming.

Synthetic material such as plastic and rubber, and naturally occurring materials such as wood, are affected by excessive exposure to UV-B. The damage ranges from discolouration to lose of mechanical strength which limit the lifetime of these materials.

The temperature of the earth’s surface also tends to increase due to higher UV incidence, resulting in the melting of ice in the high altitude areas and polar caps. This in turn leads to the rising of the level of water in seas and lakes at certain locations further leading to the land getting submerged in water.

Ozone is also found near the earth’s surface in the area known as the troposphere. In this region ozone is a pollutant and is one of the constituents of smog and acid rain. In many areas tropospheric ozone is increasing in concentration as a byproduct of the action of sunlight on emissions from vehicle exhausts, industrial solvents, paints and biomass burning. This causes irritation to lungs and eyes.

Due to the above stated serious damaging effects halocarbons now have been relegated to the environment scrap heap of history along with DDT, leaded petrol and other chemicals. Keeping in view the gravity of the situation, scientists, industrialists and politicians are now taking required steps for checking the menace of these chemicals:

Under a landmark international agreement signed in 1987 the manufacturer of CFCs have been outlawed in America and most developed countries.

A world meet on “ozone depletion substances” organised at Vienna (Austria) in December 95 had reached an agreement for maintaining cuts on the ozone depleting substances.

Chemists at Yale University, USA, have devised a safe, inexpensive and simple process for destroying existing stockpiles of CFCs. It has been reported that passing the CFCs over a bed of sodium oxalate and heating it to about 290°C transform them into harmless carbon, common salt and sodium fluoride.

International Business Machines (IBM) of California, America, largest user of Freon 113, today uses soap and water for cleaning computer circuit boards. Other computer giants like Apple have also followed IBM.

Sustained efforts are being made to curtail the use of airconditioners. It is expected that at the turn of 21st century ice-conditioning, an old method of cooling, will be back with some high-tech modifications.

In order to bring the harmful effects of ozone layer depletion in focus, the United Nations has declared September 16 as the ‘Ozone day’.

For the first time on October, 1995 Noble Prize was awarded for research relating to protection of environment. Dr Rowland, Dr Molina and theorist Dr Paul Crutzen of Germany got Noble Prize in Chemistry for discovering the atmosphere which protects us from UV rays in the sunlight.

The environmentalists are of the opinion that the hole in the ozone layer can be closed by controlling the use of CFCs. Since countries like the USA, Japan and Russia et al are contributing about 95%of anti-ozone emissions, earnest steps for the elimination of CFCs at least in phased manner should come from these giants. It is hoped, in the absence of these deadly chemicals, ozone layer will cure itself, may be in about coming 50 years or so.

Innovative European lunar probe
by Radhakrishna Rao

THE 14 nation European Space Agency (ESA), which has an active and significant space science programme, has initiated a programme called “Euromoon 2000” which would involve the launch of a lightweight lunar orbiting satellite in the year 2000. To be designed and built by 50 young scientists and engineers from across Europe, the 100-kg probe will be launched by means of an Ariane-5 booster from Kourou launch pad in French Guyana. After its launch, it will orbit the moon and map the planned landing area in greater detail in preparation for the Euromoon Lander in 2001. The Lander’s 40-kg payload allocation will accommodate amongst other scientific instrumentation for in-situ investigation of the unique site.

The Lander will aim for the “Peak of Eternal Light” on the rim of the 20-km diameter, 3-km deep Shackleton South Pole crater — a site ideally suited for establishing a future manned outpost. This location enjoys almost continuous sunlight so much so that missions can rely on solar power instead of bulky batteries or costly and potentially hazardous nuclear power packs. As a consequence of the undulating South Pole terrain, there are also permanently shadowed areas — amongst the coldest in the solar system — resulting in conditions highly favourable for the formation of frozen volatiles as suggested by the Clementine mission in 1994.

Some time back, the National Aeronautics and Space Administration (NASA) of USA launched its Lunar Prospector satellite which is currently performing polar lunar orbits surveying area of the moon’s surface rarely documented in previous missions. The date now being received back from prospector strongly suggest the presence of water ice in certain parts of lunar surface. Understandably, the presence of billions-of-year-old frozen water in proximity to Euromoon’s planned landing site would provide a tremendous boost for the implementation of the European project. The in-situ analysis of such rare substances will provide an invaluable scientific window back in time. The water’s constituent elements of hydrogen and oxygen have also the possibility of offering an essentially free supply of rocket propellant and oxygen for exploitation during future activities. European is the only mission being studied that can investigate this ice in situ while the US satellite will remain in a orbit.

The mission is particularly challenging because of the required landing precision in terrain varying between 6 km and 5 km in altitude. Achieving the required pinpoint touch-down capability would allow the future exploitation of other interesting sites. One such site is the 6-km high Malapart Mountain, 120-km from the pole from which the earth can always be seen thus allowing continuous communications with the home planet for any future outpost in the region. The “Peak of Eternal Light” is in direct view of Malapart, the twin peaks offer the tantalising possibility of both uninterrupted power and communication.

Euromoon can be seen as the initial stepup in founding the first extraterrestrial outpost, creating an infrastructure for “robotic village” controlled by a “virtual community” of earth based operators using telescience. This would indeed mark the beginning of an expansion of the human domain beyond earth without the risk or cost of manned space travel.

Plastic optical fibres
by Dipesh Satapathy

GOOD news for telecommunication companies who have for long faced bandwidth problems in fibre optic networks, especially in the last 100 meters of the fibre that goes directly to the computer, making it difficult to send and receive voluminous audio and visual data.

The use of plastic optical fibres promises to sort out the problem by increasing existing bandwidth for videos and other bandwidth-intensive applications.

The industry currently relies on copper cables to tackle the problem, but at high bandwidths it becomes unsteady resulting in loss of multimedia data transmitted.

Copper and glass fibres have been traditionally used to send data, but their inherent limitations have gradually given way to the use of plastic optical fibres.

Plastic optical fibre (POF) is a low-cost, easy-to-use fibre optic solution for short distance applications like local area networks (LANs) and provides high-speed access to Internet, according to a report in Optics and Photonics News.

Its development and acceptance has been accelerated by the growing bandwidth problems, the unsuitability of copper for high-speed data transmission because of its susceptibility to interference, and the installation cost of glass due to its fragility.

POF has a diameter of around one millimetre (mm), which is far larger than those of glass fibres (ranging from 50 micrometers to 62.5 micrometers), that makes it easier to connect critical alignments.

Copper cables are expensive and difficult to manufacture. They require use of specially designed apparatus and are very difficult to terminate.

In addition, copper is susceptible to electromagnetic interference (EMI) and electromagnetic radiation (EMR), two physical phenomenon which can impair signal transfer and disturb passage of critical data through the network.

POF is more secure than copper cables and allows for multiasking and multimedia applications that can be supported by copper cables at slower and less productive speeds.

Though high-bandwidth glass fibre is highly used in underground and vertical backbone implementations, its fragile and brittle nature leaves it vulnerable to breakages at connections making it unsuitable for horizontal systems.

Moreover, short-to-medium distance applications seldom use glass fibre because of its small diameter which make terminations very difficult and time-consuming.

A typical termination using glass fibre can take up to 45 minutes while a POF termination can take as little as two minutes. Losses due to dirt and contamination are also less in case of POF.

On the other hand, the base material in POF is polymethylmethacyclate (PMMA), a common acrylic that makes POF durable and flexible than glass fibre but limits its use to about 100 metres.

Specific characteristics of POF makes it suitable for a variety of short-haul applications.

Apart from sorting out the bandwidth problem in networks, POF can connect appliances, computers, and entertainment and security systems to create a “smart-home” network.

Because of its flexibility and immunisation to interference by factory floor noise, rugged and robust POF networks have been used successfully to provide communication links free from EMI in tough industrial manufacturing environment whereas EMI can cripple copper networks.

POF enables quick, two-way, clear and secure transfer of high-resolution multimedia data over internet with interoperability across different operating systems.

It can smoothen videoconferencing and other data-intensive applications like interactive multimedia and transmission of medical images.

The automobile industry can use lightweight and durable POF networks to link computerised sensor systems inside vehicles to increase performance and efficiency. It can also be used to incorporate accessories such as video, mini-computers, navigational equipments and fax machines inside a vehicle.

As POF is capable of delivering large amount of secure information at high speeds, it is being integrated into fighter aircraft, helicopters and ships.

High-tech uniforms are another possible application where soldiers could be equipped with lightweight, water-resistant and computing smart suits that can be plugged into computers to download and store, as well as send and receive mission-critical data allowing users to see the information on their heads-up-display.

Under the high-speed plastic network (HSPN) programme, established by the USA in the early 90’s to develop this technology, companies like Boeing, Honeywell, Packard Hughes and Boston Optical Fiber (BOF) worked for three years to bring this technology to the market.

Success of HSPN paved the way for another programme called Optical Micro Networks (OMNET) which commenced last year to incorporate fluoropolymer materials into POF and to develop new fibre designs for varied applications.

As the technology is relatively new land the material is produced by only five companies worldwide —one in the USA and four in Japan — further research is underway to overcome the existing problems in the technology so that it could be wholeheartedly accepted by the industry, the report says. (PTI)

Hazards of noise pollution
by Rohit Malik

MODERN life given rise to a new form of pollution i.e. noise pollution. Noise is rapidly becoming the most widespread environmental pollutant. No doubt, noise is a normal phenomenon of life but it is continuously disturbing human peace and tranquillity. Especially noisy are cities and factories, where many of us live and work. So congested are many cities that the quiet, traffic-free period has shrunk to only a few hours.

Necessity compels many people to accept — at least to tolerate — noisy condition both at work and at home. Urban areas in general, are more noisy than suburban or rural, and industrialised areas more than residential.

Noise pollution is the unwanted sound dumped into the environment without regard to the adverse effect it may have. Sound is called noise when it becomes loud or disagreeable particularly when it results in physiological or psychological harm. The relative loudness is expressed numerically using the decibel (dB) scale.

The menace of noise pollution growing throughout the world day by day due to population explosion, rapid industrialisation and urbanisation. The possible sources of noise pollution fall into the major categories of transportation, industrial, household and military. Of great concern are noise from off-road vehicles, construction, air traffic, home appliances, and surface transportation.

The ubiquity of noise had made many people apprehensive about its possible adverse effects on health. Human ear can take sound up to about 60 dB without damage or hearing loss. Any sound above 80 dB is potentially dangerous. Noise causes hearing loss, interferes with our sleep, and is an annoyance in our everyday life. It interferes with conversation, concentration, relaxation, and leisure. Since noise is an unfavourable factor in living environment, it is a subject of interest from the standpoint of public health.

The loss of hearing from anthropogenic noise is called sociocusis. Men generally suffer a greater loss of hearing with age than women. The continuous long-term exposure to noise level as low as 55 dB can permanently damage hearing. Noise of this level is common in many factories and jobs, especially construction and mining.

Noise can prevent us from falling asleep as soon as desired, can keep us from sleeping at all or wake us during the night. Noise affect the amount of time we spend in various stages of sleep. For example, the noisy environments increase the time we spend in light sleep and decrease deep sleep. This decreases the duration of recharging the body and mind. Such shift can have serious consequences. The physiological tension caused by lack of rest and sleep is a serious consequence in comfort of everyday life. It can lead to social friction between persons and among groups, to absenteeism from work and school.

Noise increase the heart rate, dilates the pupils, and cause muscle contraction. Evidence exists that prolonged exposure to high levels of noise causes a permanent constriction of blood vessels, which can increase the blood pressure, thereby leading to heart diseases and other physiological effects associated with noise pollution include migraine headaches, nausea, dizziness, and gastric ulcers.

Obviously, noise pollution can be reduced by producing less noise. It, is, however, impossible to have a total elimination of annoying sounds. It can certainly be minimised by taking some factors into account such as reduction of noise at source, reduction of population explosion, duration of noise exposure, etc.

Science Quiz
by J. P. Garg

1. Name the Indian scientist who not only made pioneering contribution in the field of space research but also established institutions which helped in modernisation of textile industry and development of management skills in India.

2. The USA used the photos taken by an Indian satellite in December, 1998, to estimate the destruction caused by the US and British bombers after bombing the city of Baghdad in Iraq. Name this satellite the imagery of which finds a ready international market.

3. When a charged particle passes through a suitable medium at a speed greater than the speed of light in that medium, light radiation is emitted from the particle. What is the specific name of this radiation? Why is it so named?

4. Amosite, tremolite, actinolite etc. are fibrous minerals widely used in protective clothing and for other purposes because of their chemical inertness and high resistance to heat. What is the common commercial name of these minerals?

5. Inorganic benzene has physical properties almost similar to those of organic benzene made of carbon and hydrogen. Of which elements is inorganic benzene made?

6. The term SHE has been quite popular during recent years in connection with the discovery of new elements. What does SHE stand for?

7. The process of synthesis of complex molecules from simpler ones by living things is called anabolism. What is the process of breaking down of complex molecules by living things called?

8. What and where is “Sea of Serenity”?

9. Name the animal whose genetic structure is about 98% similar to that of man.

10. This lake in Orissa, the largest wetland of its kind in Asia, is a winter home to lakhs of migratory birds but thousands of these birds are killed every year by poachers for their meat. Which is this lake?

ANSWERS
1. Vikram Ambalal Sarabhai 2. IRS-IC 3. Cerenkov radiation, named after the Russian physicist P.A. Cerenkov who discovered this effect 4. Asbestos 5. Boron, nitrogen and hydrogen 6. Super heavy elements 7. Catabolism 8. A crater on moon 9. Chimpanzee 10. Chilika lake.

‘Stealth virus” to deliver genes

IN order to develop an ideal genetic delivery vehicle, American researchers have modified a common virus so that it can carry corrective genes to defective cells without stimulating an immune response.

The result, published in the journal Human Gene Therapy, showed that adenovirus, a common cold virus, can be used successfully as the delivery vehicle to introduce genes for therapeutic purpose.

“In our set of experiments, we were not only able to deliver for more than two months,” said Dr Andrea Amalfitano, paediatric geneticist at Duke University Medical Centre, who led the team.

Scientists have long recognised that adenovirus offers many advantages as a “vector” for gene therapy. It can carry practically genes of any size, can infect virtually all cells in the body, and can be easily mass-produced.

However until now, within two to three weeks of the virus’s introduction into the body, the immune system of recipients easily recognised the virus and its gene payload as foreign and cleared it from the body, as well as the cells the virus had infected.

As a result of their findings, the Duke scientists propose a “two-hit hypothesis to explain why other adenovirus vectors usually failed.

The first immune-system “hit after an adenovirus infection comes when the animal’s immune system recognises the virus as foreign and attacks it. The second “hit” comes when the immune system recognises the introduced gene, called a transgene, as foreign and attacks it. Only after both hits occur does the immune system clear the virus from the body, along with the infected cells and the transgene.

Amalfitano and his colleagues designed their “stealth” adenovirus to evade the first hit altogether. As in previous attempts to use the adenovirus as a vector, they first deleted from the virus the “E1” gene — which is they first in a series of genes the virus needs to copy itself. However, they also detected a second, similar gene father down the same pathway.

“This double deletion makes the virus ‘quieter’ to the immune system, and allows it to deliver the transgene unnoticed,’ Amalfitano said.

Guide to yoga, meditation

Magic Software is a company known for bringing out CD-ROMs devoted to Indian topics. Its previous offerings include India Mystica, a multimedia encyclopaedia on Indian culture, traditions and beliefs; the Mahabharata, an animated storybook; and India Festiva, a step-by-step guide to the ceremonies connected with various festivals like the Lohri, Id, Ramanavami and Mahavir Jayanti.

It has now released "Yoga and Meditation, a Mantra for Better Living", an interactive encyclopaedia on the history and application of the age-old philosophy of yoga. There are five sections through which a modern-day user can access relevant information about the holistic system of conditioning both the mind and the body. "What is Yoga" provides basic orientation to the philosophy of yoga and its origins, the various branches of yoga, and the eight-fold yogic path. This section also gives an overview of the influence of yoga on the west, and its present-day status.

In a section called Postures, the concept of warming up is explained and warm-up exercises are suggested. Then the main postures are delineated, with text, "how-to" photographs and full-screen video clips with narrated instructions. A sub-section deals with the curative and beneficial aspects of each posture. For the initiated, advanced postures are also included.

Another section called Breathing deals with the various aspects of this seminal function of our bodies. A complete section tells the user about meditation techniques. Another section, A Way of life, teaches the user the relationship between various foods and personality types, and the effects of different foods on the mind and the body. Preventive measures as well as eating habits and diets that actually work to cure the body are suggested.

Throughout the title, the user is presented with lively animations and hand-drawn illustrations. The original music score is soothing.