Exciting new construction materials
by G.S. Dhillon
GEOSYNTHETICS is a "generic term" applied to cover several products such as geotextiles, geomembranes, geocomposites, geogrids etc. which have different roles to play, though they are manufactured from the same raw material.

Science Quiz
by J.P. Garg

New products & discoveries

What the future holds in store

A cure for cancer, colonies on the moon, nuclear power stations in space, the mysteries of human nature laid bare. According to experts interviewed by the Observer News Service , these are just some of the major breakthroughs within man’s grasp.

* Speciality: the human genome

* Predicts: genetic printouts for babies; reduced deaths from diseases

like cancer; reduced medical costs.

"Some time this century, when parents leave hospital with a new baby, they will take with them a genetic print out. It will include computer predictions of high-risk diseases, suggestions about the chemicals and foods in the environment that the child should avoid, and the kind of

lifestyle that will promote their child’s health and longevity.

"At the same time, the parents must be sure that there are laws which prevent the baby’s genetic code from ever being used as a weapon against it-so that the knowledge will only benefit its life. They also need to understand that genes hardly ever predict a disease with absolute certainty; they can only give an indication of risk."

* Speciality: origins of the universe

* Predicts: people on Mars; permanent lunar base; tourism in space

"I am confident that there will be a permanent lunar base and a manned exploration of Mars sometime this century. Whether it’s going to be within 20 years or 50 years is hard to predict. This would depend on whether there’s either political pressure, as was in the case of the Apollo programme to send a man to the moon, or if the techniques are cheap enough to be done by private enterprise or individual adventurers.

"Tourism in space will happen some time this century. But space flight will only be affordable when it adopts the same techniques as supersonic aircraft, and the craft does not have to be rebuilt after every takeoff. Tourist trips into orbit may then become routine for wealthy adventurers. I expect there will be self-sustained groups of people living away from the earth. A lunar colony couldn’t be justified by science alone, but if it were established for other reasons it would offer superb scientific opportunities.

* Speciality: novel energy sources

* Predicts: hydrogen fuel; nuclear waste dumps in outer space; bio-mass generators in the back garden

"I think of the 20th century as the century of the internal combustion engine. The 21st century will be the age of the hydrogen economy. Hydrogen is a very powerful, very clean fuel. If you take a fuel cell - a type of battery which burns hydrogen and air to make electricity - the exhaust is hot, distilled water, without all the pollutants that are discharged from a combustion engine. But at this point there are a number of technical problems which need to be overcome, including safe storage, because hydrogen is highly flammable. The other problem is cost. We are trying to develop cells which are cheap enough to power automobiles.

"We’ve also been working on what is called bio-mass — turning natural materials like wood chips, grass or the residue from agricultural crops into fuels that can be used to power vehicles that are not reliant on petroleum. You would eventually have a bio-refinery that is not unlike today’s oil refinery, but much greener. Ultimately, we will enjoy a more sustainable energy position at the end of this century than at the beginning".

* Speciality: bio-medicine

* Predicts: artificial organs; human nerve cells for sale in chemists’ shops

"In 10 to 20 years’ time, we think we will be able to build new organs artificially and replace an entire organ with something synthetic. So whenever someone’s health is compromised by a specific organ dysfunction, which is 75 to 80 per cent of people, we’ll have the technology to support them. Heart failure, strokes, cirrhosis, loss of kidney function and diabetes could all be treated.

"But this therapeutic organ cloning will not increase our life span because, no matter what you replace, we will all eventually collapse. People who live to 110 will still die in their sleep because so many of their life support systems fail. In three to five years, human clinical trials of cell therapy - using living cells as pills - will begin. We are already making these in the lab and testing on animals.

* Speciality: smart materials

* Predicts: aerial vehicles; self-repairing cars; treating inoperable

cancers

"It is possible that within 50 to 80 years, families will not have a car but an aerial vehicle. Owners would wheel it out of the garage and take off vertically. Most would fly below 3,000ft, but there is no engineering reason why they couldn’t fly at altitudes of up to 80,000ft. A two-seater aerial vehicle would be saucer-shaped, 15-20ft in diameter, and travel at speeds up to 320kph. An in-built computer would link the aerial vehicle to air traffic control systems, and if propulsion failed, they would be able to glide to earth, just as some helicopters are already able to.

"One of the building blocks for the development of aerial vehicles is adaptive materials, which we are working on at Auburn. These structures are capable of changing their shape when applied with heat, electrical signals or magnetic fluids. The materials would be able to repair themselves and adapt in shape, to operate in much the same way that muscles act in birds and insects.

* Speciality: neuroscience

* Predicts: hundreds more mental diseases; an understanding of human nature "I think the next big scientific frontier is the brain and mind. Human beings are driven by a curiosity to understand cosmology, the universe, physics, biology, genetics, but we still don’t know ourselves. What is human nature? That’s the ultimate question and that’s going to answered this century.

"By advances in brain imaging [which allow us to investigate what real brains are up to in the real world-as opposed to studying dead brains-through a process of placing them in a static magnetic field and observing oxygen flow], we are going to find many more transmitters and receptors in the brain than was previously believed. How these affect our attitudes, emotions or sexuality, for instance, will be established.

Exciting new construction materials
by G.S. Dhillon

GEOSYNTHETICS is a "generic term" applied to cover several products such as geotextiles, geomembranes, geocomposites, geogrids etc. which have different roles to play, though they are manufactured from the same raw material.

These products can be used to perform several functions on the civil engineering front and can be used to replace some of the natural mineral products like sands, gravels, aggregates etc. The geosynthetics can be called upon to perform one or more of the following functions:

(i) Separator to keep apart two types of soils or materials.

(ii) Filter.

(iii) Erosion control and interface protection.

(iv) Tensioned membrane to impart strength to weak foundation soil.

The most commonly used synthetic fibres in the manufacture of geosynthetics are: polypropylene, polyester, polyethylene, and poly-amide (nylon). For high strength products polyesters are used.

Non-woven (needle punched) fabric is being currently manufactured by number of units located at Delhi, Vadodra, Bangalore, Mumbai etc. The woven products are also available in the market. These are made from long-chain polymeric filaments composed of polypropylene oriented in a stable network. Such a material is inert to soil and chemicals and the fabrics are sufficiently strong and durable even in the most hostile environments, such as those possessing pH ranging between 3 and 11. The material is lightweight (350 gms/sq. mtr).

The first use of "woven synthetic fibre" as erosion control measure, was made in 1958. In 1969 the use of non-woven fabric was made to increase the bearing capacity of soil. In 1972, the use was made of geo-grids as separator of ballast from soil. In 1970s the US Army Corps evolved design methods for use of geosynthetics as "filter elements" in earth dams. By the year 1978 several dams had been built using such material as filter in place of sand and gravel used earlier.

Use of thick non-woven geotextiles as drain sheets has been made for ensuring escape of trapped gases or for ventilation of the surfaces and also the role as filters, as an alternative to aggregate filters, to permit free-flow of water without significant loss of soil particles and head of water.

* RDSO (Lucknow) has used both woven and non-woven materials under rail-tracks for keeping loss of ballast to bare minimum, at the same time ensuring good riding quality for fast track trains (speeds up to 150 kmph) and high traffic density.

* CRRI (New Delhi) had undertaken field studies using geosynthetics as road-base materials in black cotton areas, where roads undergo rapid deterioration due to high moisture levels. Trials covered a length of 13 km of trial roads.

* The Ministry of Surface Transport (New Delhi) has used geogrids for slope-protection and erosion control at several locations with good results.

* CBRI (Roorkee) has used geogrids for reinforcing the soil behind retaining walls at several locations, where land slips had occurred earlier. Similar use was made by IIT (Mumbai).

* IIT (Kanpur) and the Indian Institute of Sciences (Bangalore) have undertaken work for evolving design procedures for strengthening weak foundations through use of geogrids.

* In Punjab, on the Hoshiarpur-Dasuya Road, geogrid has been used for imparting strength to embankments of approach roads of 600 ft span bridge. The geosynthetic material used in this case was to play an effective role as erosion control measure in addition to imparting strength to the sandy foundation soil.

The use of geosynthetics in the water resources projects are as follows: i) For land reclamation with hydraulic fills, ii) geomembranes-geotextiles composites in the rock — fill and earth dams, iii) Canal Lining, iv) Break-waters, jetties and erosion control measures. The various uses to which the geotextile can be put to is shown in Figure 1.

Canal Lining: The IPRI (Amritsar) has evolved a composite type lining in which low density polythene (LDPE) of thickness varying between 250 microns and 1000 microns is used in the bed of the canal and provided with one foot thick soil cover and rigid type (brick masonry or tile) lining on the sides.

Erosion Control Measures: Geotextiles have been successfully used to perform the role earlier assigned to the graded filters of natural aggregates, but care is needed to safeguard against the geotextile getting punctured by sharp stones of "rip-rap".

Role as Filters: The most cases of failure of earth dams is due to internal erosion of core materials, particularly when the clay used happens to have dispersive character. Non-woven geotextile when used as filter will have much smaller thickness compared to the conventional graded filters.

Experience has shown that in case of woven geotextiles, the filteration efficiency would depend upon the "mesh size" and the mesh-size to be selected would depend upon the size of soil to be protected. In the case of the non-woven geotextiles, the filteration properties depend upon the size of hole or punch mark made during "punching process". The material can have permeability comparable with sand or gravel materials.

Use of Geosynthetics as Drains: There has been a phenomenal increase in the use of non-woven geosynthetics materials for serving the drainage function. A composite system comprising fabrics and mineral aggregate in geo-composites, has been found to be cost-effective when the fabrics are used to perform the task of filteration and drainage.

Science Quiz
by J.P. Garg

1. When the Indian mathematician Srinivasa Ramanujan was travelling in a cab with the British mathematician G.H. Hardy, the Englishman commented that the number of cab in front, 1729, was a dull number. “No”, replied Ramanujan, “it is a very interesting number. It is the smallest number expressible as a sum of two cubes in two different ways”. Can you show how?

2. Indian and US astronomers have recently discovered jointly a new type of galaxy which is millions of light years away from our own galaxy Milky Way. Can you name this galaxy which will help obtain information about very distant constellations?

3. It is possible that within a few years, our devices, appliances, clothes and probably everything else we possess may have computer capability. What name has been given by the experts to such a situation?

4. This region located at the base of the brain contains centres which regulate the body’s temperature, hunger, thirst, sleep, sexual activity, etc. Can you name this gland which is also involved in the body’s emotional and nervous activity?

5. For what purpose are benzoic acid, potassium metasulphite and sodium metasulphite generally used in our homes and how do they serve this purpose?

6. This study includes the evolution, classification, structure, function, distribution, reproduction, migration and behaviour of birds. What is this study called?

7. Plants are sometimes propagated by using shoots that arise from the underground parts of the plant. What are these shots called?

8. The boiling point of water decreases with increase in height above the sea level. An instrument based on this principle is used to measure height above sea level. Can you name this instrument?

9. What is the process of slow heating and cooling of a metal, alloy or glass called so as to remove any imperfections within the material?

10. Name the first American astronaut to walk in space in June 3,1965, who spent 14 minutes outside the spacecraft Gemini 4.

Answers

1. 1729=1³+12³ and 9³+10³ 2. Hybrid Morphology Radio Sources 3. Pervasive computing 4. Hypothalamus 5. For preserving fruit juices, squashes, jams, pickles, etc; they inhibit the growth of micro-organisms that spoil these materials 6. Ornithology 7. Suckers 8. Hypsometer 9. Annealing 10. Major Edward White.

New products & discoveries

Instant energy in a bottle
THE 0.5 litre rechargeable high pressure gas bottle attached to a thermal imaging camera by means of a quick release valve and self-sealing connector, supplies pure air for the efficient operation of the camera. This is an example of a British company’s technique for providing vital pure air for aerospace, defence and industrial applications.

Officially called pneumatic energy stores, the bottles can be tailor-made in a variety of shapes and sizes to fill whatever space remains on a designer’s drawing.

The British company has developed special techniques for storage of gases at very high pressure up to 1,150 bar [17,000psi]. These techniques provide a “single shot” rechargeable power source of high energy density available for instant use at any time over a period of more than 10 years. The bottles are machined from high grade stainless steel to ensure strength and freedom from impurities and are then electron bean welded to make them leak tight, and inspected to ensure their safety.

In addition to manufacturing the bottle, the company has also developed lightweight air compressors for cleaning and recharging them. It has also developed a range of rapid inflation systems for airborne, surface and underwater use.

Few rats can trigger plague: scientists
PLAGUE can re-emerge, vaccination is useless and mass killing of rats is really not a solution for eradication of the disease, according to British scientists who have warned that towns with more than 3000 rats per square kilometer are potentially vulnerable for plague outbreaks.

Plague eradication is difficult, say M J Keeling and C A Gilligan of the University of Cambridge who have developed a mathematical model for predicting the conditions under which plague outbreaks can occur that would help authorities take precautions. Their report is published in a recent issue of the journal Nature.

“Plague is primarily a disease of rodents that is spread by fleas and only occasionally infects humans,” the scientists say. “When the infected rat dies its fleas leave to search for new host rodents. When the density of the rats is low, the fleas are forced to feed on alternative hosts like humans and a human epidemic occurs,” their report says.

The British scientists have formulated an “animal-based” disease model for the rat and flea population and by coupling this with a standard epidemic human disease model are able to identity epidemic patterns and the circumstances in which the disease causes a large number of human cases.

Safe-handling hydrogen generator
A SAFE, portable, hydrogen gas generator has been developed which makes high-purity hydrogen gas by combining cobalt, ruthenium or other transition metal catalysts with an aqueous alkaline solution of sodium borohydride (NABH4).

The generator has been developed by scientists at Millennium Cell LLC of Eatontown, New Jersey.

According to Steven Amendola, vice president of research and development, “These non-flammable sodium borohydride (NABH4) solutions are aimstable and can be kept in open beakers at room temperature”.

“When these solution contact the high surface area of the catalyst, a rapid hydrolysis reaction starts generating hydrogen gas; withdraw the catalyst and the reaction stops”, he said.

The difference between Millennium Cell’s hydrogen-generating method and hydrogen-reforming methods is one of exothermic versus endothermic reactions, Amendola said.

Detecting cracks in airliners
ENGINEERS in the USA have found a new method for detecting tiny cracks in aging aircraft parts before they reach the catastrophic stage.

The new method, developed by combining two technologies — laser heating and ultrasonic inspection — improved detection of fatigue cracks by a factor of ten over previously known methods.

University of Cincinnati Graduate Zhongvu Yan and associate professor of aeroscape engineering Peter Nagy tested their method using a series of aluminium and titanium specimens with cracks ranging from 0.5 to 1 mm in length and specimens with no cracks in them.

The results indicated that the method not only finds the cracks but also measures the difference in the severity of the cracking.

The material degrades on the microscopic level and one cannot really see the cracks, Navy said adding that cracks move through older aircraft parts much faster than cracks in newer ones.

Nagy’s previous work focused solely on aluminium alloys, material typically used in the aircraft fuselage while the current project expands that work to titanium alloys used in the engine parts.