Diamonds in the sky
by B.R. Sood
DIAMONDS have for millennia, fascinated human beings because of their glitter, sparkle and lustre. Scientists have also had an attraction for diamonds because of their special physical properties like exceptional hardness and the phenomenon of total internal reflection of light within the diamond.

Satellite based positioning
by Balraj Singh
As long as we live among familiar surroundings, we don’t have to worry about getting lost. However, knowing one’s position becomes extremely important for those gone hiking, to the ocean explorations, deserts, forests or flying over unknown regions etc.

Science Quiz
by J. P. Garg

New products & discoveries

International space station
A new abode in the sky
by D.P. Singh

A symbol of international cooperation, the largest structure ever built in space and the gigantic space project ever undertaken is the International Space Station (ISS). It promises untold discoveries for the next millennium, ones that benefit all mankind.

The ISS is a collaborative project of 16 countries, including the USA, Russia, Canada, Japan, Brazil and 11 European nations. The docking of a Russian module with an American one by astronauts of the space shuttle ‘Endeavour’ in December 1998 marked the beginning of this space station. It will be completed in 2003.

The genesis of the International Space Station (ISS) goes back to the early 1980s. In 1984 announced plans for setting up a giant space station ‘Freedom’ by mid-1990s. But the project could not take off due to successive budget cuts, which seriously curtailed the American space programme.

In 1953, as the Russians were desperately looking for funds to continue their cash-starved Mir mission, the USA decided to cooperate with Russia to build a new space station. Thus the idea of the construction of the ISS took birth.

Until now, Russian built pressurised control module —”Zarya” and US built drum shaped passageway “Unity” have been placed in orbit at 385 kilometres above the Pacific Ocean. During their 6.5 hours of space walk two astronauts have hooked up the electrical connections between the two modules.

The third piece to go up was Russian Service Module. It was launched unpiloted and docked with other end of the Zarya module using automated docking procedures. The service module houses the sleeping areas, kitchen and toilet for the station’s crew.

During the next four and half years, as many as 90 shuttle and Soyuz missions will ferry hundreds of components for the station. Astronauts will undertake several hundred hours of space walk to assemble these components in orbit. It will have large solar panels, which are likely to occupy more than an acre of space area.

On completion, the ISS will have pressurised space-occupying volume equal to two jumbo jets. By then a total of 16 solar panels covering about 4000 square metres will be in place, producing electric power to run this multi-room hotel cum world-class laboratory. The space station will orbiting the earth every 90 minutes.

The ISS will be equipped with the latest state-of-the-art facilities. It will have six laboratory modules, one each from the US, Europe and Japan, two from Russia and one module built in Japan and operated by NASA.

Its permanent crew will be six or seven. With flights to the station becoming routine events, Americans, Russians, Europeans and Japanese astronauts will move in and out of ISS over the coming months and years.

The gravitational force on board the ISS will be only one-millionth of the force felt on earth. Researchers say, without the interference of earth’s gravity many otherwise hidden processes could be revealed in basic science research.

The studies carried out under microgravity could lead to new treatments for diseases, better materials and alloys and even more efficient ways to use fuels.

The ISS will also provide opportunities to study long-term physiological effects of microgravity. The study will help us in designing life-support systems for long space missions, which will be valuable for future manned-missions to planets like Mars.

A symbol of our future and a new abode in the sky, the ISS is expected to provide a unique environment for scientific research leading to untold discoveries benefiting all mankind.

Diamonds in the sky
by B.R. Sood

DIAMONDS have for millennia, fascinated human beings because of their glitter, sparkle and lustre. Scientists have also had an attraction for diamonds because of their special physical properties like exceptional hardness and the phenomenon of total internal reflection of light within the diamond. Later phenomenon is responsible for sparkle in diamonds, Diamond is nothing but a single crystal of carbon atoms. In a single crystal atoms are arranged in an orderly fashion along a set pattern. In a diamond carbon atoms forming tetrahedrons are stacked together to yield a three-dimensional structure. Because of hardness diamonds, for times immemorial, have been used as glass cutters and as industrial abrasives for smoothening and polishing of surfaces.

Diamonds, methane gas and the planet Neptune, on the face of it, do not seem to have anything in common. But recent research has established a close link between the three. Methane molecule (CH4) consists of one carbon atom at the centre of a tetrahedron and four hydrogen atoms at its corners. It is the simplest molecule belonging to a family of widespread molecules known as hydrocarbons. It is an established fact that methane accounts for about 15% mass of Neptune. Other constituents of the planet Neptune are lighter gases hydrogen and helium. Methane, being heavier, forms the inner core of Neptune and hydrogen-helium combination forms its atmosphere covering about 4000 km around the core. Pressure exerted by the atmospheric gases is estimated to be around two lakh times the atmospheric pressure on earth (two lakh atmosphere) at 4000 km below the atmospheric gases increasing to five lakh atmosphere at 7000 km. High pressure forces methane to condense into a fluid. In addition temperature of the methane core is around 2500°C. Such temperature and pressure are far more intense than that exist in the molten core of earth.

It was predicted on a theoretical basis that under such extreme conditions methane in the core of Neptune must be crushed to yield its basic constituents, carbon and hydrogen, and further carbon atoms should combine and give rise to crystalline form of carbon i.e. diamond.

Thus there is a strong possibility that the inner core of giant planet Neptune contains millions of tons of diamond subject to the condition that methane under conditions of extremely high pressure and temperature gets converted into diamond as predicted theoretically.

To verify this premise a team of researchers in the USA undertook an experimental study recently. Methane gas was subjected to high pressure of five lakh atmospheres and its temperature was raised to 3000°C. Methane was found to react on expected lines giving rise to two products, one being diamond and the other a polymerised hydrocarbon. Presence of diamond in laboratory experiment simulating conditions existing on Neptune prove that Neptune is a storehouse of diamonds. Pressure at which reaction starts in the laboratory is less by a factor of 10 than theoretically predicted value implying that breakdown of methane in Neptune occurs around 7000 km below atmospheric gases and further down.

Implications of the existence of high pressure chemical reaction are far reaching and add a new dimension to the proper understanding of gaseous planets. So far the accepted picture of these large size planets far away from the sun is that of layers of various gases or of mixtures of gases of fixed compositions. Light shed by high pressure induced chemical reaction has given impetus towards a more realistic dynamic occurrences inside the core of Neptune. Dimonds produced in the process being denser than the surrounding medium from which they are created sink deeper towards the centre under the influence of planet's force of gravity. In this act gravitational potential energy is released in the form of heat. This heat energy churns the interior of the planet. Churning manifests itself in different forms. Churning firstly can boost the magnetic field of the planet and can also account for heat energy radiated away from the planet. Establishment of a link between diamonds, methane and the planet Neptune has definitely added a new dimension to the understanding of the state of affairs within the giant gaseous planets.

Satellite based positioning
by Balraj Singh

As long as we live among familiar surroundings, we don’t have to worry about getting lost. However, knowing one’s position becomes extremely important for those gone hiking, to the ocean explorations, deserts, forests or flying over unknown regions etc. In olden days, magnetic compass, clocks and positions of celestial objects were referred in order to determine one’s course and position. In modern times, however, things have been made a lot easier — thanks due to satellite based positioning systems like GLONASS (Global Navigation Satellite System), Transit and GPS (Global Positioning System). Among these, GPS is the most useful and popular system.

The working principle of GPS can be understood from fig. 1. The satellites transmit two types of data — navigation messages, carrying satellite position data and coarser time divisions; and Gold codes, carrying fine time divisions from their highly synchronised clocks.

Since the satellites are at different distances from the receiver at a given time, there is a slight difference between the received time signals. The GPS receiver calculates these differences against its internal clock. Each difference multiplied by the speed of light, ‘c’ gives distance from a particular satellite.

But since the receiver has an inexpensive crystal clock, each measurement has the same, constant error. This problem can be visualised as a number of spheres with their centres at four satellites and radii equal to their respective calculated distances. Ideally, all these spheres should be intersecting at a common point, where the receiver is located. But, this does not happen because of the constant error in each calculated distance.

This problem can be solved uniquely only if we have a minimum of four such spheres, or for that matter, four satellites, simultaneously above the horizon at any given place. In that case, the errors can be easily rectified through a simple iterative algorithm and the precise position as well as time can be obtained.

In order to ensure that four satellites always remain visible at every point on Earth, GPS employs a constellation of 24 satellites in 6 orbits at 20,000 km height and 55° inclination to equator, as shown in fig 2.

Another interesting thing about GPS is that it provides a platform to study the effects of Special and General Theories of Relativity. The Special Theory of Relativity predicts that the satellite clocks should appear to tick at a slower rate as they are in motion (Time Dilation), while the General Theory predicts that these clocks should tick faster since they are at a lower gravitational potential. This later effect is nearly double in magnitude than the former is case of GPS satellites. Accordingly, they tick about 27 nanoseconds faster every minute. Proportionate changes in the clock speeds were made prior to the launch of satellites.The satellite data is transmitted in two code modulations — C/A (Coarse Acquisition) and P (Precise). C/A can give an accuracy of around 15-25 metres But, in order to ensure that others don’t make the best use of GPS, some error was deliberately introduced into its time signal, which increases the positional error to 100 metres. This error can only be decoded through the P codes, which are secret. However, any country can install a local transmitter of its own at a known place and transmit its own P codes. This is known as differential GPS (DGPS) and gives an accuracy of around five metres.

GPS has many peacetime applications like area mapping, resource planning, path optimisation, aviation and navigation aids, while its military applications include real time tracking of pilot-less crafts, precise target selection, moving men and material to pre-selected positions in unknown regions etc. During Gulf War, GPS had its first and successful military application.

Science Quiz
by J. P. Garg

1. This Russian physiologist is known for his pioneering research about the digestive process, his theory of conditioned reflex’ about animal behaviour and extension of this theory to human psychology and the treatment of mental illness. Name this winner of 1904 Nobel Prize for physiology or medicine.

2. The number of human organs available for transplantation in the world is far short of the number of patients requiring this treatment. In order to cover this shortage, animal organs may be transplanted into humans in future. What is this type of transplantation called? Which animal has been recently cloned by a British biopharmaceutical company with this purpose in view?

3. An Indian scientist working in Britain and his colleague there have recently discovered the possibility of development of tamper-proof computers. Their theory is based on a new law of quantum mechanics called “quantum no-deleting”. What name has been given to these computers?

4. Name the first transuranic element. Who produced it first of all and in which year?

5. ‘Pyrene’ is a fire extinguisher. When sprinkled over a burning object, it changes into non-flammable vapours which surround the fire and consequently cut off air supply to the burning object. What is pyrene chemically?

6. If you hold a pen vertically at a distance from your eyes and look at it first with one eye and then with the other, it appears to move relative to other distant objects. What name has been given to this apparent shift in the position of an object? In which physical quantity is this shift measured?

7. Which is the heaviest planet of our solar system? About how many times is it heavier than the earth?

8. Genetic engineering is a technique of altering the genetic makeup of an organism and finds many applications in various fields. Suggest another name for this technique.

9. ‘Balata’ is a rubber like material. Which type of playing balls are normally made from it?

10. A mineral found in the moon rocks has been named by combining the surnames of three astronauts: Armstrong, Aldrin and Collins. Can you name this mineral?

Answers

1. Ivan Petrovich Pavlov 2. Xenotransplantation; Pig 3. Quantum Computers 4. Neptunium; US Physical chemists Edwin McMilan and Philip Abelson in 1940 5. Carbon tetrachloride 6. Parallax; as an angle 7. Jupiter; 318 times 8. Recombinant DNA technology 9. Golf balls 10. Armalcolite.

New products & discoveries

Conic clocks with witty remarks
For those who are ever chasing deadlines, getting their blood pressures up and becoming robots with each passing day, here’s little bit of fun. From the crucible of ceramic artist Fred Babb who stays in San Fransisco, comes a collection of whacky clocks.

These are no ordinary clocks but ones that will make you smile as you go through the motions of workaday life. Babb has designed all his clocks mostly on faces of cats, each with a witty remark. You have a happy looking cat telling you, “Let’s go to lunch” as the watch strikes twelve. Then there is a particularly smug looking cat which says “later” and is described as “The procrastinator”. Or the one which reminds you to take time out for yourself. With so much to get worked about, Babb sure has found a way that can humour people.

Art work that really works
A “working sculpture” will restore canal navigation linking Glasgow and Edinburgh, Scotland, by 2001.

The 35-metre-diameter Falkirk Wheel is rotating boat-lift that will reopen the link between the Forth/Clyde and Union canals by replacing a flight of 16 locks that closed in the 1930s.

Designed by Butterley Engineering and Edinburgh’s RMJM, the 1,300-tonne wheel costing £ 78 million will move boats up and down the 24-metre rise from the Forth/Clyde to the union canal in 15 minutes.

The project also includes the construction of a new section of canal at Wester Hailes near Edinburgh, two aqueducts, three locks, a tunnel, railway bridge and canal basin. (LPS)

Biosensor for food safety
A new bacterial sensing device that can detect at least six micro-organisms in food items has been developed by US researchers.

The biosensor was developed at the Georgia Tech Research Institute (GTRI). It can simultaneously identify species and determine concentrations of multiple pathogens — including the deadly E. coli 0157:H7 and Salmonella — in food products in less than two hours while in operation on a processing plant floor.

“The most significant advantage of the biosensor is the time reduction in assessing the presence of contamination,” says Nile Hartman, a senior research engineer at GTRI.

Tests for bacterial pathogens in meat are currently costly and slow — sometimes not even yielding results for 48 to 72 hours. The delay requires that food products remain stored in warehouses for longer periods.

“The biosensor will help in overall quality control in food processing plants.” says collaborator Paul Edmonds, a professor of biology at Georgia Tech. “It would minimise the chance of the final product being contaminated.”

Tractor to detect landmines
A British company has developed a new armoured tractor that can detect anti-personnel mines in harsh terrains.

The demining tractor, developed by researchers of Pearson Engineering Limited in New Castle, can be fitted with a range of implements that enables it to operate effectively in minefields.

The simple, robust, easy-to-operate and highly flexible tractor can replace the time-consuming and painstaking manual methods of locating anti-personnel mines, reports Spectrum.

It runs on large-diameter open-frame steel wheels and weighs nearly ten tonnes.

Options for the tractor’s fittings include a segmented roller with individually floating discs to detonate surface anti-personnel mines, and a heavy vegetation cutter that slashes down branches and small saplings.