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| SCIENCE TRIBUNE | Thursday, April 5, 2001, Chandigarh, India |
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Intelligent
sensors New relay to eliminate flat battery problem Spectrograms to measure microquakes |
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Nuclear hazards to electronic systems White rot fungus to deink
wastepapers NEW PRODUCTS & DISCOVERIES
SCIENCE QUIZ
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Mir space station’s deadly
plunge WITH the demise of Mir an era of international cooperation and understanding has come to an end. By providing valuable help in devising ways of minimising the harmful physiological effects in space travellers due to their prolonged exposure to zero gravity, Mir has successfully served its purpose. The possibility of setting up permanently manned orbiting space stations was seen as a logical continuation of mankind’s push into space, especially after the first moonlanding in 1969.The first manned space station was Salyut 1, which was launched by the erstwhile Soviet Union in 1971. Six more Salyut stations, the last of which was abandoned in 1986, followed it. The first American space station, Skylab, was launched in 1973. Four teams of astronauts visited it to carry out various experiments till it was abandoned in 1974. The Salyut and Skylab missions provided space scientists valuable experience to develop the technology to sustain crews in space for long periods. The Soviet Mir station, which was launched in 1986, was much more sophisticated and spacious. It had individual pressurised modules devoted to different purposes. Since its launch, the Mir had been continuously occupied, with periodic replacement of crews. In 1988 two Soviet cosmonauts spent more than a year on board the space station setting a record of sorts of endurance in living in microgravity environment. The Mir experience has provided valuable help in devising ways of minimising the harmful physiological effects of prolonged exposure to zero gravity that earlier astronauts had experienced. In 1993, after the breakup of the Soviet Union, 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. As a part of the programme, American astronauts were sent to the Mir station periodically, not only to learn how to keep fit in the microgravity environment, but also to imbibe the culture of long-duration missions. But more than that, they demonstrated the importance of cooperation in space. The experience with the problem-ridden Mir station, which has seen everything, from a collision and explosion to a big fire on board, has given the builders of the International Space Station (a collaborative project of 16 countries and is likely to be completed in 2003) enough confidence to face the future boldly. The Mir station also provided the scientists with the experience to survive on recycled water and wastes in cramped space stations. Mission Control lost contact with Mir for 20 hours in December, 2000, because of a sudden power loss. Space officials since tried to minimise power consumption by switching off most of the station’s equipment. They also allowed Mir to roll, because keeping it stable would use limited fuel reserves. Thus the famous Mir Station has become a part of history after playing its vital part in man’s quest of conquering the space. |
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Intelligent
sensors A human being with the five senses of taste, smell, sound, sight and touch is the greatest sensor engineered by God. Yes, we talk of sensors invariably in all the fields, be it process industries like chemical, petrochemical or fertilisers and the fields of medical science, agriculture, space and oceanography. Simply put, a sensor is a device which comes in touch with a measurand or variable present in any changes it into a form which can be further conditioned and used for displaying and control. “An Intelligent Sensor” is the hottest topic of conversation in any control room or an engineering department. As the developments in the sensor field took place, the ideal of combining the sensor and electronics in the same package lead to what is an intelligent integrated smart internally and it can be interfaced with a computer for on line application. With the vertical growth of industrial measurement systems, the traditional sensors posed the problems of compensations and signal processing which overloaded the central processing facilities. Moreover, transmission of raw unprocessed data threatened the ability of existing communication system. Furthermore, analog encoding forced the use of traditional star topology, thus raising the cost and complexity of the system. With the vertical growth of industrial measurement systems, the traditional sensors posed the problems of compensation and signal processing which overloaded the central processing facilities. Moreover, transmission of raw unprocessed data threatened the ability of existing communication system. Furthermore, analog encoding forced the use of traditional star topology, thus raising the cost and complexity of the system. With the breakthrough in smart sensor technology, the related processing of the signal is done within or close to the sensor housing in such a way that the potential performance of the sensor is not affected significantly by the presence of extra processing electronics. The silicon based intelligence incorporated at the point of measurement in a smart sensor provides it the ability to react to and manipulate inputs. In addition it can also tailor outputs, interact with control networks and respond to network instructions. These sensors are capable of communicating in a non-analog fashion. Digital communication of the highway addressable to remote transducer (HART) type is the most common protocol used with the smart sensors. The mode of communication in a smart sensor enhances its efficiency and accuracy of information distribution. The advantages of smart sensors include higher performance, better flexibility, less maintenance and more diagnostic capability. Besides their capability to manipulate and send data to personal computers or controllers, smart sensors solve even basic problems. The small size and high power of these micro-machined sensors allow intelligent monitoring of process variables in areas where conventional instrumentation cannot be adapted. Construction of smart sensor or “sensor on the chip” package is resistant to overpressure, shock and vibration. Smart sensors are commonly available in traditional instrumentation packaging and are capable of having better signal-to-noise ration because of on-chip signal conditioning. Smart sensors also provide for improvement of characteristics of sensors like non-linearity, cross-sensitivity, parameter drift etc using on chip feedback systems or look up tables. This allows periodic and automatic calibration of sensor. Smart sensor also has signal conditioning and formatting capabilities such as analog-to-digital conversion and impedance matching. Addressibility
is another important attribute of smart sensor which develops the concept of logical organisation of sensor in a multivariable process. Addressibility employs some form of polling of devices which can also be prioritised in various ways to get to a particular sensor site.
Applications Since chemical hazards pose a great threat to mankind hence chemical sensing is one of the most important areas of sensing. Many basic types of chemical sensors like chemi-resistors, fuel cells, chem-FET’s are available, but all have disadvantages of specificity and susceptibility to poisoning. The intelligent chemical sensor takes care of this as it has many sensing elements, each sensitive to a different gas. Careful processing of responses of these sensing elements gives a reliable measure of gas composition. Fiber optics technology also provides a promising platform for smart sensors. Optical fibers can be used to sense the changes in chemistry and in physical properties such as pressure, temperature, strain and magnetic field strength. The use of light instead of electricity is safer in explosive or hazardous environment. Tactile sensors can be used to determine the shape, size, weight and surface tension of a part by touching it. The main commercial uses of smart sensors are
Today the needs of the industry are tilted towards the requirement for standards. However the need of the day is reliability combined with low-cost technology. Future advancements should be directed towards the design of very sophisticated measurement and control systems. Whatsoever be the developments, it should be borne in mind that the rapid advances in technology should be aimed towards long term commitment. Due attention should be paid to the fundamentals in order to achieve the sole aim of benefitting mankind. |
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New relay to eliminate flat battery problem A
new technology has been developed by which flat car batteries could soon be a thing of the past. The new technology a relay system that ensures the battery voltage is always at a high enough level for the vehicle to start — has been developed by scientists in the UK and is currently undergoing tests. The relay system invented by Jonathan Laker a director in Smartswitch company, has a small printed circuit board that detects when the voltage drops to a pre-set level and automatically shuts down the relay to prevent any further discharge. When the driver tries to restart his car, the relay activates once again. Fitting the relay is easy because the new device simply replaces the vehicle’s existing relay without any modification to electrical
system. Laker invented the relay system after he had received two unrelated appeals in quick succession for jump-lead starts from friends stranded on the motorway, both with flat batteries. In each case, the friends had left their lights on, which had resulted in battery failure. Laker decided there must be a way to stop such problems with an inexpensive device that was easy to install and required no major alternation to vehicle’s wiring.
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Spectrograms to measure microquakes SCIENTISTS are now able to distinguish between natural micro-earthquakes and underground chemical explosions by using “Spectrograms” developed by Bhabha Atomic Research Centre (BARC) in Mumbai. A recent study by BARC at its Gauribidanur Array (GBA), Karnataka, has shown that microearthquakes and chemical explosion like quarry or mine blasts have different source mechanism and could be easily distinguished by “Spectrograms” according to Dr Tapas K Basu of the Seismology Division of BARC. GBA, which continuously records several micro-earthquakes, showed that the “Spectrograms” of seismic signals give a three dimensional representation — time, frequency and amplitude — of seismic wave energy reaching a recording station which in turn provides detailed insight into the source functions and the event signatures. BARC has also developed a rugged, cost-effective and simple multi-channel data acquisition system called “stand alone” for unattended short term and long term recording of seismic data at local and regional instances from seismic sources.
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Nuclear hazards to electronic systems NUCLEAR radiation is a result of both fusion and fission reactions. The explosion of nuclear device causes tremendous havoc. It generates plasma of high temperature and high-pressure gases. The constituents of these gases are the atomic nuclei and the free electrons. The net outcome is the emission of electromagnetic radiations of gamma and X-rays. The X-rays are absorbed in the surrounding air resulting in a luminous fireball which re-radiates energy. The electromagnetic
pulse output of a nuclear device can seriously affect an electronic system. Nuclear radiations due to neutron displacement cause the major damage to electronic systems. Neutrons collide with the lattice atoms of the semiconductor and dislodge them. Further, when X-rays and gamma rays penetrate the innermost electron shell of the atom a large amount of energy is released. The strategic defence electronic systems should be designed in such a way that they are not prone to nuclear radiations. The transistors chosen should be of high gain so that they compensate for the gain loss due to nuclear radiations. The construction of a collector with a thin epitaxial minimises the neutron effect. Virtually all MOS devices are resistant to neutron damage. Other material which can be used is microwave diodes like PIN, IMATT and GUN. Gas devices are also highly resistant to fast neutrons. The electronic devices for the military warfare have to be critically designed so that they can counter the nuclear radiations. Issues pertaining to Nuclear Survivability are the prominent areas of research worldwide. |
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White rot fungus to deink wastepapers SCIENTISTS have found that inoculation of wastepaper like newsprint, writing and printing papers with white-rot fungus results in their deinking — an important step for the recycling of paper. Recycling of wastepaper has become important due to increase in paper price and to overcome the problem of pollution. Deinking of wastepapers is done chemically by the use of detergents. However, application of biotechnology in the pulp and paper industry is gaining popularity as it reduces environmentally hazardous wastes. According to a report in the Journal of Scientific and Industrial Research, scientists in the Cellulose and Paper Department of the National Research Centre in Cairo, Egypt cut the waste newsprint, printing and writing paper into small pieces and immersed them into warm water at about 50 degree celsius for at least three hours. The wastepaper of all three kinds was inoculated with spores of the fungus Phanerochaet chrysosporium separately for one week at about 32 degree celsius under sterilised conditions, the report said. The scientists then prepared handsheets from untreated and deinked paper and determined properties like brightness, opacity, tensile strength and tearing resistance.
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NEW PRODUCTS & DISCOVERIES SO what’s new about a bicycle? Ask the Japanese and they’ll tell you there’s plenty. Because their attention has now been focused on this high-utility elementary contraption used for decades by people around the world. The result is the Suzuki Love 24 bicycle. It is fitted with a high-speed rechargeable battery unit which, when switched on, takes over the controls of the bike. Interestingly, the bicycle remains as lightweight and compact as the original one because the battery pack fits on the slope of the bar and makes pedalling very easy and comfortable. The difference between this bicycle and a moped is that the battery doesn’t drive the bike but only makes pedals very light to operate. It also energises the light, brakes and bell. Needless to say, the power-assisted bike is a big success in Japan and is scheduled to make its debut in other parts of the world shortly. The gadget will go a long way in making even a long drive pleasurable thanks to the feather-touch pedalling system. And also to the fact that it would cost for less than a moped and slightly more than an ordinary bicycle.
NF Removing coins from food pipe A team of doctors in Jaipur have developed a “loop basket” that can remove, without injuring body organs, foreign bodies like coins and seeds swallowed inadvertently. Foreign bodies that are round and larger than the size of the loop basket can also be removed if their major portion comes inside the loop basket, gastroenterologist of SMS Hospital Sandeep Nijhawan told PTI. The endoscopic devices, used traditionally to remove foreign bodies from the food pipe, include grasping forceps, baskets and snares, he said. The loop basket has an advantage over polypectomy snare and grasping basket as the chance of smooth and rounded objects slipping out of the basket during the removal is almost nil, he added. Foreign bodies commonly get lodged in the upper gastrointestinal tract. Though majority of them pass out of the system, about 20 per cent require endoscopic removal.
PTI Warning signal before quake No natural calamity comes without a warning, except and earthquake. But now scientists seem to have found crucial warning signals of an earthquake. The moon and a sudden burst of neutrons may provide key warning signals of a major earthquake. While researchers admit that predicting an earthquake is impossible, a new study has found a novel way to forecast the rumblings from the bowels of the earth a day in advance. In an innovative study, Russian physicists have found that earth gives out warning signals in the form of flashes of neutron radiation just before increase in the earth’s seismic activity. They believe that this phenomenon can be reliably used as an innovative way to predict where and when an earthquake would strike. In the study, the researchers of the Department of Cosmic Radiation of the Research Institute of Nuclear Physics at Moscow State University have also noticed that major quakes occur at new moon and full moon periods. And it is at these periods that there is a sharp increase in the intensity of neutron radiation. This steep signature increase in neutron radiation is found prominently in areas of seismic activity. According to the scientists, the neutron flashes are caused by tidal forces, which, in turn, trigger earthquakes. The scientists believe that the neutron flashes can be used as reliable pre-signs of earthquakes. In a paper published on internet following the Gujarat quake, the physicists said day and night alterations of neutron flows were observed in the Pamir mountains, near Gerino, at a height of 1100 m above the sea level. It was found that neutron flashes have a period of 12 hours. This fact confirmed the link between neutron flashes and the passing of maximum tidal waves through the earth’s crust. At the days of new moon or full moon, when the Sun, the Moon and the Earth are in a line, a total gravitational impact on the earth is maximum. Through the cracks, atomic and nuclear particles and radioactive gases (containing radon isotopes) are ejected. The decay of isotopes at the surface earth layer and in the air produces a lot of alpha-particles — intermediates between radioactive gases and neutrons. The researchers measured flows of alpha particles in the Pamir mountains and found alterations in downs times compared to the average earth level. The Moscow researchers studied the catalogue of earthquakes from 1964 to 1992. They found that most severe earthquakes in the region of the Pacific seismic ring also started at the days of new moon or full moon, or a couple of days earlier or later. In these period flashes of neutron radiation with intensity dozen times higher than background level are observed in the areas of seismic activity, so the scientists suggest using the neutron flows of short-term earthquake forecast.
PTI Bug-propelled
subs Researchers are developing a novel biomotor that can zip round the body delivering drugs and zapping tumours. Researchers from Utah presented their idea of the microscopic submarine powered by bacteria at the Foresight conference on Molecular nanotechnology in Bethesda, Maryland. The team plans to attach swimming bacteria cells to vanes mounted on top of a silicon disc sealed inside a tiny liquid-filled cylinder. Their natural movement would push the disc around, turning a shaft and generating mechanical energy. With bacterial cells as the power source, the motors would only have to be a few tens of micrometers wide. The motor would be ideal for navigating round the human body, says co-designer Eldrid Sequeira, a nanotechnology researcher at Utah State University in Logan. Later, the team hopes to build biomotors using only the bacteria’s flagella and their drive mechanisms. By ditching the unneeded parts of the cells, they could shrink down the biomotors to the 100-nanometre range and run even smaller robots in the future.
PTI Happy helpers of electronics A modular hardware and software platform, which can be used to equip a whole family of service robots is all set to revolutionise development of robots, aimed at reducing the human work load. This platform concept, developed by Christopher Schaeffer at the Fraunhofer Institute for Manufacturing Engineering and Automation IPA in Stuttgart, has enabled the long-envisaged development of marketable robot systems. The versions completed are a museum robot, the CARE robot, a cleaning robot, a climbing robot and a robot firefighter, a Fraunhofer Gesellschaft release said. The decentralised hardware structure of firefighter networked mechanical components was designed by Till May, Schaeffer explains. “And of crucial importance too, is the innovative software architecture developed by Andreas Traub. These modular and easily reconfigured software components allow even highly complex control systems for mobile robots to be put together rapidly and reliably.” The development will go a long way in designing robots to make life easier. Robots which can take over the monotonous job like dusting, vacuum cleaning and coffee-making are long-dreamt of gadgets. What everybody dreams of is a robot with no or limited human intervention.
PTI Search for the ‘soma’ plant A team of Indian scientists has contested the widely accepted research of a US scientist which says that a mushroom, Amanita muscaria, is the sacred Vedic plant ‘Soma’, and has called for more research in the area. According to Vedic literature, juice of the Soma plant (Soma rasa) was considered to be a divine drink with medical efficacy. It acted as a restorative for natural health, Dr S.N. Padhy from the Department of Botany of Orissa’s Government Science College, said. Padhy, who is heading a team which is searching the actual Soma plant, said the plant was neither hallucinogenic nor intoxicating but kept its consumer awakened and alert. It has remained an enigma for botanists as it has not been identified with definite perfection. US scientists R.E. Schultes and A. Hoffman had proposed the mushroom, Amanita muscaria, as the Soma plant in their book ‘Plant of Gods’ in 1979, he said, adding the acceptance of this proposal is so high that Ethnobotanical Society’s emblem has this mushroom marked as Soma plant. “Our argument is based on the fact that this mushroom, in contrast to the Vedic Soma, produces hallucinogenic and intoxicating drug,” he said. “Somaras” was neither hallucinogenic nor intoxicating.
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SCIENCE QUIZ 1. This American physicist had nothing to do with science, either at school or at college. But he had to teach elementary physics in a school under forced circumstances and never looked back. Later he was awarded the 1923 Nobel Prize for physics for his measurement of the electronic charge and his work on photoelectric effect. Name this physicist who also found the precise value of Planck’s constant. 2. Scientists at the Indian Institute of Science, Bangalore, have recently developed a new type of solar cell, called CIGS, for converting light into electricity. Being more efficient and cheaper than the silicon cell, the new film cell is likely to revolutionise the solar photovoltaic industry within a few years. What is the complete name of CIGS, by developing which India has taken a lead over countries like the USA, Germany and Japan? 3. The latest achievement in genetic engineering is the creation of the first primate born with alien genes. Name this primate. Which foreign gene does it carry? 4. In this Japanese technique, seeds of huge trees are sown in pots and instead of big trees, small ornamental plants are made to develop. What is this technique/these type of plants called? 5. If you were a student of petrology, what would you be mainly studying and researching? 6. Methanol, ethanol, ethene, benzene and toluene are some of the organic compounds prepared from the hydrocarbons obtained from petroleum or natural gas. What general name is given to such compounds? 7. Above a certain temperature, a ferromagnetic (a substance strongly attracted by a magnet) becomes a paramagnetic (a substance feebly attracted by a magnet). What is this temperature called? 8. A star produces light by the process of nuclear fusion of hydrogen into helium. How does a “shooting star” produce light? 9. In this process, a powdered substance is heated to just below its melting points and the particles form a solid mass. What is this process called which is mainly used in case of glass, ceramics, etc? 10. The Russian space station Mir was finally brought down and plunged into the Pacific Ocean on March 23, 2001. On which date was it launched? (In last week’s quiz, question No.5 should have read: “We all assume Newton’s laws of motion to be normally valid. Under what condition do these laws no longer remain valid?) Answers 1. Robert Andrews Millikan |
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