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What high-rise buildings
need
When mushrooms go wild
Genetic “barcode” for all species
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What high-rise buildings
need
While the department is busy in preparing new and attractive plans that may add to the beauty and utility of the city, there are certain essential features that must be kept in view during the design of these buildings to make them safe and workable. These features are discussed below: 1. Earthquake Resistant Design: It is obvious that the more is the height of a building, the more prone it is to earthquake forces. The buildings are, therefore, needed to be made earthquake resistant by adopting framed structure design, by following the latest BIS code stipulations and by designing them through "Shear Wall concept". Chandigarh falls in Seismic Zone IV and these days, buildings are designed for one zone up. In case Soft Storeys (for parking purpose) are planned in these buildings, design criteria for soft storey and extreme soft storey also needs to be kept in view. 2. Fire safety: Fire safety is another important factor to be kept in mind. The city has not to give birth to "Towering Infernos". Safe exit routes and escape stairs should be planned in the buildings. The electrical equipment and installations provided in the buildings must be of high standard as shortcircuits are the most common cause behind breakout of fires. The buildings should be designed to carry an emergency power supply in addition to the main supply which should automatically switch off in case of fire. The emergency supply should turn on to run ventilation fans. Sufficient area around each building should be kept open and unoccupied for free movement of fire-tenders. Shafts for electric cables should be run separate and not common with those for water supply and telephone lines. These should be provided with fire resistance seals. Provision of smoke detectors, automatic fire sensing systems and sprinkler systems should be made to the possible extent. 3. Transportation system: Having a fast and efficient vertical transport system is another factor that must be counted while planning the high-rise buildings. A "Traffic study" involving accurate assessment of building users may be made. Peak demand hours should be identified. Elevators should be located in the central core of the buildings. All cars (elevators) should be fitted with overload devices and automatic rescue devices (ARD) which send the cars to nearest floors in case of power failures and even open the doors. 4. Essential services: Provision of proper water supply, sewerage and drainage facilities is essential for successful and trouble-free use pf buildings. Water pressure on the upper floors should be same as that at lower levels. Sewerage and drainage must be adequate, efficient and having easy access for repairs and replacement of pipes and joints. 5. Parking facilities: The buildings must be provided with sufficient parking space. Underground parking system has its disadvantages. If enough ground space is not available, a common multi-storeyed parking lot for a cluster of buildings can prove attractive as well as practical. 6. Construction features: In order to ensure proper quality and safety in construction, the building plan drawings themselves should specify use of ready-mixed concrete in construction. Any good company will readily agree to set up a RMC plant if the quantum of work is sufficient. Use of super plasticisers and sophisticated form work should also be specified. Accidents should be declared intolerable and safety assigned top priority. Let us hope that not a single worker loses his life during construction of these high-rise buildings. With the availability of user-friendly design software packages, sophisticated and versatile equipment and good quality ISI marked materials, it is not difficult to add the above features to the buildings. — The writer has penned several books
on high-rise construction |
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When mushrooms go wild
This is the dark, mysterious and surprisingly violent world of fungi. These organisms spend their lives searching for new sources of food, and, when two fungi come across the same piece of dead wood or pile of leaves, a battle for supremacy can ensue. At Cardiff University, Prof Lynne Boddy has been studying fungus wars for more than 20 years. Boddy’s motivation is to try to develop a fuller understanding of these interactions, of the role fungi play in the wider ecosystem of the woodland, and of the 3.9 billion hectares of the earth that is covered by forest. “After all,” she says of her work, “before we can save the planet we need to know how it works.” Fungi are supreme waste-recyclers. They release nutrients locked up in dead tissues and make them available again. Because of this, the ecology of the fungus is crucial to the wider ecology and health of the woodland. Professor Boddy has set up conflicts between different species of fungus and watched as one defeated the other. “We have arranged fights between scores of different fungi and have a sort of league table,” Boddy says. “Some are much better fighters than others. But just because one fungus is top of the table it doesn’t mean it’s going to win every time. Just like sports teams, some fungi have their bogey opponents who they simply can’t beat.” When we think of a fungus we usually envisage a mushroom or toadstool,
or occasionally a bracket fungus clinging to the side of a tree. But these external manifestations are merely the fruiting bodies — the structures that produce the spores. —
By arrangement with The Independent, London |
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Genetic “barcode” for all species An ambitious project to take a genetic “barcode” of every animal and plant has began in an attempt to identify and label the 10 million species living on earth. Biologists say that the plan to give every species its own barcode — made from a stretch DNA unique to each lifeform — will help them to understand the bewildering diversity of life. The DNA barcode will represent a segment of a gene that differs from one species to the next but is almost identical to all members of the same species. DNA barcodes look superficially like supermarket barcodes and will work in much the same way in helping field biologists to carry out an audit of life by distinguishing between closely related species. Less than a fifth of the estimated 10 million species of plants and animals have been formally named and classified and many experts fear that thousands are at risk of becoming extinct before they are even identified. Scientists hope to name the rest of the unknown species by 2010 as part of the international Barcoding of Life project, said Richard Lane, director of science at the Natural History Museum in London. “There is no consensus about the rate at which we are losing species,” Dr Lane says. —
By arrangement with The Independent, London. |
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This Universe Q. Why are some objects transparent and others opaque?
Normally, when we talk of objects being transparent or opaque, we describe whether or not visible light can pass through them without too much attenuation. What is transparent in that narrow band of frequencies we call the visible region of the spectrum might be opaque at other frequencies. For example, our atmosphere is transparent to visible light and radio waves but it is opaque at a rather large band of wavelengths in the infrared region, and to ultraviolet, x-rays and gamma rays. Transparency depends on the fact that the medium has no energy levels that could be excited by the photons of the light in question. An interesting case much in the news today is that of ozone. Ozone consists of molecules made of three atoms of oxygen. The ozone molecule has just the right energy levels to absorb lower ultraviolet radiation, and therefore protects us from its harmful effects. A small amount of ozone in the upper atmosphere can do what a large amount of air below cannot. The same ultraviolet cannot find an energy level in nitrogen or oxygen of air that would resonantly absorb it and stop it from coming down to ground level; it can scatter its way down to the earth. This is the reason we are so worried about ozone depletion. Take another example. Long wave radio works because the ionosphere does not allow such waves to escape out into space, but reflects them back. Short wave or television signals pass through the ionosphere almost unhindered. Therefore, we need satellites high up in space to retransmit these signals back to earth to provide global television and short wave radio. Transparency will result if there are few energy levels in the medium that can help in absorbing the signal. This is true of glass in the optical region of the spectrum. The same glass is not so transparent in the infrared. That is why in summer a closed car sitting out in the sun becomes so hot inside. When you come back after some shopping and open the door of the car it feels like an oven. The heat radiation inside has a hard time getting out through the glass widows and windshields. The incoming energy gets shifted to wavelengths that get imprisoned by the very same windows and windshield that are optically transparent. The much talked of the possibility of global warming, resulting from increasing concentration of carbon dioxide, is a similar effect. Q. Why do light bulbs immediately begin to glow as the current is turned on, and tubelights require a few seconds?
The filament in the light bulb is made of a high resistance wire. The heat capacity of this wire is low. Therefore, it is quickly raised to a temperature high enough to balance the energy emitted as light and heat and that produced through Ohmic loss by the current flowing through the filament. That is why the light bulb begins to glow quickly. When you switch on a tubelight, the current cannot pass unless a plasma discharge is started by delivering a high voltage pulse. You would remember that the starters of ordinary tubelights contain ballast and a condenser. The ballast is essentially a high impedance choke. The condenser reduces the electromagnetic interference. The heating of the electrodes at both ends of the tube leads to emission of electrons, which are the initial carriers of the current for the discharge. The current for heating the electrodes is cut off after the discharge begins, because the electrode temperature is then kept high by the impinging ions. The high voltage to initiate the discharge is produced by interrupting the current in the ballast. The initial heating time of the electrodes and building in the required sequencing takes a little time. This is the reason why ordinary tube lights require a few moments before they begin emitting light.
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E-gatekeeper outsmarted
A team of computer scientists has unravelled the codes of tiny radio devices that protect cars from theft and prevent fraudulent petrol purchases. The exercise in reverse engineering by researchers at Johns Hopkins University in Baltimore and RSA Laboratories in Bedford, Mass., shows that “an attacker with modest resources — just a few hundred dollars” of off-the-shelf equipment — can crack the codes of millions of car keys and the stubby wands that trigger the pumps at ExxonMobil gas stations, the team reports in a draft article.. “There is a practical risk here,” says team member Ari Juels of RSA, the company that created an encryption technique used throughout the Internet. The team has withheld from its article critical code-breaking details that could abet would-be hackers. The makers of products that rely on the security technology say that without those key specifics, criminals are unlikely to achieve what the Johns Hopkins-RSA team has.
A mini solar system
Moons circle planets, and planets circle stars. Now, astronomers have learned that planets may also circle celestial bodies almost as small as planets. NASA’s Spitzer Space Telescope has spotted a dusty disk of The brown dwarf, called OTS 44, is only 15 times the mass of Jupiter. Previously, the smallest brown dwarf known to host a planet-forming disk was 25 to 30 times more massive than Jupiter. The finding will ultimately help astronomers better understand how and where planets — including rocky ones resembling our own — form. “There may be a host of miniature solar systems out there, in which planets orbit brown dwarfs,” said Dr. Kevin Luhman, lead author of the new study from the Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass. “This leads to all sorts of new questions, like ‘Could life exist on such planets?’ or ‘What do you call a planet circling a planet-sized body? A moon or a planet?’”  |
On January 03, 2005,
the Punjab Governor gave the green signal for a change of Chandigarh
skyline when, during a presentation by the Architectural Department,
he exhorted the architects and planners to come up with new ideas and
plan high-rise buildings in the city by making practical and judicious
use of land in the periphery. This landmark decision is in tune with
the present times when the development arrow has shifted its direction
from horizontal to vertical and there is no alternative to vertical
expansion if the burgeoning population of the city is to be provided
with homes and the slogan ‘Shelter for all’ is to be converted
into a workable policy.
A
quiet stroll in the woods can be the perfect antidote to a noisy, fume-filled, jostling urban jungle. But while on the surface everything may appear calm and tranquil, beneath the feet, in the rotting leaves and in the dead branches, silent battles are being fought with a terrible ferocity. 