Latest developments on steel front
by Jagvir Goyal
THE advent of thermo mechanically treated steel bars and corrosion resistance steel has heralded a new era of economy in the construction industry in India.

Latest developments on steel front
by Jagvir Goyal

THE advent of thermo mechanically treated (TMT) steel bars and corrosion resistance steel (CRS) has heralded a new era of economy in the construction industry in India. Round plain steel ruled over this industry up to sixties while Tor steel took over the scene in seventies and maintained its supremacy till nineties. 1997 and 1998 has now seen an extensive use of TMT steel and corrosion resistance steel thereby ushering in greater economy and longer life for RCC structures.

Reinforced cement concrete (RCC) today has become an integral part of every structure, be it a multi-storeyed building, a tunnel, a flyover, a TV tower, a bridge, a nuclear reactor, an industrial unit or a residential apartment. With RCC so much coming under use, the engineers are constantly striving to devise ways and means to reduce its cost and bring economy in construction. Among its constituent materials, RCC has steel as the costliest material. Therefore, the focus has been more on steel than on any other constituent material.

Steel alone accounts for 30 to 40% of the cost of RCC. It can be in the form of mild steel, medium tensile steel, high tensile steel, deformed bars, high tensile steel wires, hard-drawn steel wire fabric, twisted steel fabric and so on but the mild steel and the deformed bars have remained under most common use.

Initially, conventional mild steel used to be put as reinforcement in RCC works. In 1967, tor steel (trade name for deformed bars) was introduced in India and due to its advantageous properties, it completely replaced the mild steel except a few situations where acute bending was required in higher diameters of steel bars. Tor steel, called grade Tor-40, with its characteristic strength of 415N/sq mm proved to be much economical than the conventional mild steel having a strength of 250 N/sq. mm only. While there has been a very small difference in their price-range, Tor steel is almost 65% stronger than mild steel and thus directly affects economy in RCC works.

Since 1967, about 40 million tonnes of steel has been saved in India only because of replacement of mild steel by the Tor-40 steel. This occurred because the quantity of Tor-40 steel used to be almost 40 per cent lesser than that of mild steel for the same structure. At the present cost of steel, the saving amounts to Rs 50,000 crore. Working out the figures for the whole of the world is a mind — boggling exercise.

Research and development continued even after the discovery of Tor-40 steel. Aim has been to discover still better quality of steel without ignoring the fact that steel for reinforcement has to be basically a low-carbon steel and an alloy of iron and carbon. Higher the yield strength of steel, lower will be the steel requirement and thus lower will be the cost of steel and RCC. Efforts in this direction have borne fruit. Recently, more superior grades of steel have been discovered.

Superior grades of steel thus developed are known as Tor-50 and Tor-55. These grades with their characteristic strengths of 500 N/sq mm and 550 N/sq mm, respectively are much stronger than Tor 40 grade steel and mild steel. Use of Tor-50 and Tor-55 steel permits a larger spacing among bars avoiding congestion as these bars possess a higher yield strength and a lesser number of them is required.

While Tor-40 steel brings a saving of 35% cost when used in place of round steel, Tor-50 and Tor-55 grades can bring an additional saving of 10% and 14%, respectively. For a four storeyed building, the saving that can be made by using superior grades of steel is shown in table.

Thermo mechanically treated steel known as TMT steel can be described as a new-generation-high-strength steel having superior properties such as weldability, strength, ductility and bendability meeting highest quality standards at international level. Under thermo mechanical treatment of bars, the steel bars are made to pass through a specially designed water cooling system where these are kept for such a period that outer surface of bars becomes colder while the core remains hot. This creates a temperature gradient in the bars. When the bars are taken out of the cooling system, the heat flows from the core to the outer surface causing further tempering of steel bars thereby helping them in attaining higher yield strength of steel.

To decide the percentage of carbon content in steel has been a major challenge for the engineers. While a certain minimum carbon content in steel is essential to achieve the required strength, an excess of carbon content threatens its property of weldability. In TMT bars, this problem has been eliminated. In these bars, the carbon content can be restricted to 0.2% to attain weldability and at the same time no strength is lost on this account. The joints can be welded by ordinary electrodes and no extra precautions are required. SAIL and RINL (Rastriya Ispat Nigam Limited) are doing a good job in producing TMT bars.

Another advantage of TMT bars is their tough surface providing high yield strength and a soft core providing excellent ductility. Strength, weldability and ductility are such properties which declare TMT steel highly economical and safe for use. An additional advantage of TMT steel is that a twisting operation is included in Tor steel, which subjects the bars to torsional stresses making them less corrosion resistant while TMT bars are free of such stresses thus having superior corrosion resistance.

A new development on steel front is production of corrosion resistant steel, called CRS. Carbon content in this steel is restricted to 0.18%, Mangnese is absent, silicon is 0.45% and the percentage of corrosion resistant elements such as chromium is as high as 1.5%. The smaller is the diameter of steel, the greater are the chances of its getting corroded. Corrosion of steel occurs mostly due to chloride ion effect or carbonation. Instead of conventional method of providing metallic coatings to steel, a change in the metallurgy of steel itself is finding its way now. SAIL and TISCO have taken great strides in this direction.

Further research towards production of fusion bound epoxy coated reinforcement steel and corrosion resistant low alloy steel is under way. To meet with the increasing demand of electrical industry SAIL has intensified its efforts to produce sophisticated silicon steel. Interesting results in this direction are expected soon.

Learn Urdu online

THE reach and advantages of the Internet are being gradually comprehended more and more in India and put to good use. One of the unlikely results of this modern-day medium is its application in popularisation of Urdu. That the language is one of the sweetest is beyond question. It is just that it is not the in-fashion language as far as the urge to learn it is concerned.

One website that is doing a good job in popularisation of Urdu is www.urdustan.com. It has been in existence for two years now and gives the lovers of Urdu much that they love. Every month it selects a nazm and posts in on the Net. This month’s nazm is “Asli Insani Zewar” from the book Bahishti Zewar by Maulana Ashraf Ali Thanwi. The previous nazms have been Ghalib, Prem Chand, Meer and Akbar Allahabadi.

One section teaches you to learn Urdu online. Another tests your knowledge of Urdu. The third one tells you the history of Urdu poetry while yet another one is on interactive Urdu.

But perhaps the most useful of them all is “Talaash”, an Urdu search engine. The votes of many of you may go instead to the online dictionary section, which tells you the meaning of a lot of words.

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NASA website had gained tremendous popularity when a spacecraft had landed on the Mars. It had virtually the whole world clicking to see the photographs of the buggy moving slowly but steadily. It is not quite so hot these days but a visit to http://station.nasa.gov always yields worthwhile results. These days the focus is on the first steps by STS-88 scientists in the orbital construction of the international space station. The photos that it stores are stunning.

You also get the astronaut’s voice recordings. Visitors can send their comments to NASA’s news section curator Sudha V. Chudamani.

The website takes pains to ensure that it does not end up being too technical. That is why it even poses simple questions, such as “how fast a spaceship has to be to leave the earth”. (In case you do not know, it is 17,500 miles per hour for orbiting the earth and 25,000 miles per hour to escape the orbit.)

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If satellite images fascinate you, try out http://terraserver.microsoft. com. All the tales that you have been hearing about the spy in the sky being able to snoop on you come true. A pity that photographs of very few areas of India are available but for the rest of the world, there is a treasure trove available. (Mind you, these are in black and white.) The astrodome at Houston, the Brandenburg Gate in Berlin, the Grand Canyon … they are all there. My personal favourite is the satellite image of the B-52 aircraft parked in Tucson (Arizona). How Oh how did the satellites missed the Pokhran blasts?

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And to see the images of the Indian famous spots and to read about them, you will have to go to www.greatbuildings.com. Most of the buildings are from Europe and America again but there are quite a few Indian ones as well. The Taj Mahal and the Qutub Minar are of course there. The surprising part is that so are lesser known ones like the Asian Games village, Fatehpur Sikri, even the Assembly Hall at Chandigarh.

However, I did not succeed in downloading the 3-D models of these architectural marvels.

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India is indeed coming on its own. If you do not have the all-India yellowpages, you can make do with www.indiayellowpages.com. All the information that you can get from the directory can then be had on the Internet. The only problem is that the text takes ages to load and the search at times yields funny results. I tried out the Indian Airlines and could get a lot of info on everything under the Indian sun except the airlines.

1. Tathagat Avtar Tulsi of Bihar has broken yet another record by graduating in physics at the age of 11 years and 2 months. Whom did he surpass in this achievement?

2. Continuing on the subject, name the mathematical wizard from Bihar who was awarded the graduate degree by Patna University while he was still in first year and who orally did some calculations at Nasa faster than a computer could do.

3. An eco-friendly biodegradable plastic has been recently developed at an Indian institute. Which is this institute? Name the engineer who has made this plastic that will degrade in just six months, whereas normal plastic takes about a hundred years to degrade.

4. Children are generally administered a combined vaccine MMR before five years of age. Which three diseases does this vaccine prevent?

5. Some US researchers have found that during physical exercise, the human heart releases a protein that can protect cardiac muscles from damage in the event of a heart attack. What is this protein called?

6. The glass top of the box of a solar cooker allows the heat from sun’s rays enter inside but does not allow most of the heat to escape out. What is this effect called?

7. India successfully won the patents dispute against the USA in case of turmeric but it has failed to do so in case of basmati rice. By which name has this quality rice been patented by the US firm Rice Tec?

8. Name the unmanned spacecrafts launched by the USA towards Mars on December 12, 1998, and January 3, 1999, to probe the planet’s atmosphere and landscape for signs of water. When will these spacecrafts reach Mars?

9. This predatory dinosaur had no teeth, its head was birdlike and its three-fingered hands were quite adept in lifting and holding the eggs which it stole from the nests of other dinosaurs. Name this dinosaur.

Visvesvwrarya Industrial and Technological Museum and Birla Industrial and Technological Museum are two unique science museums in India. In which cities are these located?

Answers

1. Jay Luo of the USA who graduated in science at a little over 12 years of age 2. Vishva Narain Singh 3. Central Tuber Crops Research Institute, Thiruvanthapuram; S.K. Nanda 4. Measles, mumps, rubella 5. Heart Shock Protein 6. Greenhouse effect 7. “Texmati” 8. Mars Climate Orbiter and Mars Polar Lander; In September and December, 1999, respectively 9. Oviraptor also known as “Egg Thief” 10. Bangalore and Calcutta.

Fabrication technology

Scientists at IBM’s Zurich Research Laboratory in Switzerland have developed a tiny “light stamp” to each fine structures — as fine as 100 nanometres (one nanometre is one millionth part of a millimetre) on thin silicon wafers.

The new micro-fabrication technology may well herald a new era in fabricating micro-circuits required for miniaturised electronic devices, reports the Industrial Physicist.

Today’s microelectronic devices are made with several layers of circuits and connecting wires. Each layer is formed by repeating the conventional photolithographic process, which requires dozens of steps that must be precisely aligned with one another.

But IBM researchers have used a pliable light-coupling mask, called “light-stamp”, which can be placed directly on a silicon surface. Protruding features on the light stamp form the pattern which is to be transferred to the silicon wafer.

Landmarc to detect landmines

By combining radar and imaging technologies U.S. researchers are developing a new landmine detection system to increase accuracy in detecting all kinds of landmines. Being developed by researchers at Lawrence Livemore National Laboratory (LANL) the system called landmine Detection Advanced Radar Concept (LANDMARC), is being designed to perform better than existing systems and can detect small plastic antipersonnel mines which were earlier difficult to detect, according to a report in the journal IEEE Potentials.

Antitank mines can be easily detected by detectors and ground-penetrating radars but antipersonnel mines made of plastic pose a difficult problem. Moreover, all existing devices frequently record false alarms from cluttered sources.

Space-age tech to stop crooks

In an effort to apply the tools of space exploration to a broader array of applications, some NASA technologies may be showing up at crime scenes.

These new technologies have been dubbed teleforensics. Logistics in a big reason for law enforcement’s interest in the project.

Using this technology, forensics experts could gather and digitise evidences at the crime scene and enter it into an on-site computer. Then, using satellite communication, the data could be beamed to crime lab for swift analysis, reports Mechanical Engineering.

Each instrument in the system compacts the data and sends them to a Central Processing Unit (CPU) in the spacecraft. The information is then transmitted back to earth and unpacked to permit rapid determination of quality analysis.

The analytic technology can greatly help criminal investigators: allowing crime lab staffs to participate remotely in the proper collection of data securing an area of evidence and maintaining the chain of evidence to keep it form being corrupted before a trial.

Magnetic tracks for vehicles

US researchers have come up with a magnetic track for trains and other vehicles based on the principle of magnetic levitation or maglev in which a special arrangement of permanent magnets is used to make vehicles rise and move in air.

Though Earnshaw’s theorem, published in 1839, stated that no combination of attracting or repelling magnets can stably leviate another magnet held in their magnetic fields, Klaus Halbach of the Lawrence Berkeley National Laboratory came out with a special arrangement of permanent magnets called “Halbach arrays” that sidestep the restrictions of Earnshaw’s theorem.

Richard F Post and J Ray Smith of Lawrence Livermore National Laboratory (LLNL) have developed a version of the Halbach array that provides an ideal track for trains and vehicles to levitate.

A train operating on the new maglev system called Inductrack needs wheels to support it at rest and while it acclerates to levitation speeds, reports Industrial Physicist.

Power-flow controller

A new device to control the flow of electricity around the U.S. national power grid in a highly flexible way has been developed by researchers.

Developed by American Electric Power (AEP) i n Colombus, Ohio, the system called Unified Power Flow Controller (UPFC) which makes it possible for transmission operators to instantaneously and continuously control the flow of alternating current power on grids, reports Mechanical Engineering.

Transmission voltage and power can be independently controlled using the 138-kilovolt system which offers a cost-effective way to increase the amount of power that can be transferred.

Past attempts to control power flow through the transmission network were impeded by mechanical devices that were too slow, too inflexible, and insufficiently durable.