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Anti-gravity effect Trends
Methane makers Flowing nano ripples Comet sampler Stent repair Prof Yash
Pal
THIS UNIVERSE |
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Eco-friendly cars Even sparing the ever-increasing cost of fuel, car has no more remained the status symbol of the middle class section of Indian society but has become an integral part of changing lifestyle towards greater immovability. Car is taken as a most comfortable mode of family transportation within manageable distances. No doubt in the last few decades car manufacturing has progressed a lot towards low cost and fuel-efficient designs. At present, car prices (cheapest) are already affordable and in times to come these (prices) will come well within the reach of a general section of the middle class families. Such users will always be looking for a more durable, fuel-efficient and low-price cars, as they will be thinking it as one-time investment. Moreover, with the increasing fuel prices and growing environment consciousness, sustained, environmentally compatible and conservative use of resources is a major factor from the start in developing new car concepts. To make a vehicle fuel-efficient, lighter, strong and cost effective, the automobile industry is seeking a lighter structural material. Steel is the material of choice today because of its strength and low cost. But steel is heavy. So the industry is starting to use lighter materials instead from fiberglass to aluminum. To meet the ultimate goal, one potentially enabling technology is to use carbon-fiber composites. Experts have determined that carbon fiber body-shells or body structures, by reducing fuel consumption to an above-average extent during the use of a vehicle, are able to offer significant benefits in terms of their ecological balance. The superior properties of carbon fiber to steel and other metals meant that the aerospace industry was an obvious market for composite materials. Presently, carbon fibers are used extensively in both military and civil aircraft structures. As the technology of producing composites advanced, other fibers are being developed to supply the market. So far carbon fiber or composite carbon materials have been used mainly for individual components particularly where the material used has to withstand heavy loads whilst keeping weight to a minimum and thus offering supreme stiffness and strength. Designers and construction engineers are now planning to use carbon-fiber-reinforced plastics to an increasing extent. The big advantage of carbon fiber is that it is one-fifth the weight of steel yet just as strong and stiff, which makes it ideal for structural or semi-structural components in automobiles. Replacing even half the ferrous metals in current automobiles could reduce a vehicle's weight by 60 per cent and fuel consumption by 30 per cent, according to some studies. The resulting gains in fuel efficiency, made in part because smaller engines could be used with lighter vehicles, would also reduce greenhouse gas and other emissions by 10 per cent to 20 per cent. All of this would come with no sacrifice in safety, as preliminary results of computer crash simulations show that cars made from carbon fiber would be just as safe - perhaps even safer - than today's automobiles. Today's Formula 1 racers are required by mandate to be made from carbon fiber to meet safety requirements. The problem is that carbon-fiber composites cost at least 20 times as much as steel, and the automobile industry is not interested in using them until the price of carbon fiber drops from Rs 800 to 500 (and preferably about Rs 100-200) per kg. At that price, it would become feasible for automakers to use such composites in the manufacturing of cars. Various automakers are working to lower the cost of carbon fiber composites. If they are successful in developing high-volume renewable sources of carbon fiber then these feedstocks are believed to be on the road to success. Then, the highways of tomorrow might be filled with lighter, cleaner and more fuel-efficient eco-friendly automobiles made in part from recycled plastics, lignin from wood pulp and cellulose. Production of carbon fibers is too expensive and slow. The raw material is typically pitch, or polyacrylonitrile (PAN) precursor. It is converted to carbon fibers using thermal pyrolysis, a slow, energy-consuming process that is combined with stressing to achieve the right properties. The precursor, the energy needed to heat it to make fibers, and the large ovens and other capital equipment required in the process contribute to the high cost. Researchers of several industrial teams are exploring alternative precursors to reduce carbon fiber raw material costs. Progress in developing affordable carbon fiber composites has been steady and researchers are working to optimise raw materials and spinning processes for alternative forms of carbon fiber precursors from renewable sources. Investigators and industrial collaborators have demonstrated that microwave heating of PAN precursor in a plasma instead of using less-energy-efficient thermal processing increases the speed and reduces the cost of producing carbon fibers. The project showed that a properly designed and implemented microwave-assisted plasma energy delivery system might quadruple production speed and reduce energy needs and fiber price by up to 20 per cent. Researchers also are working to develop techniques to allow high-volume cost-effective processing of carbon fiber, hybrid glass-carbon fiber and reinforced thermoplastic material forms. Lightweight means better fuel efficiency, which translates into big savings in the face of rising oil prices. Global demand for carbon fiber is estimated at 25,000 tons per year. Some analysts expect that demand will grow to 40,000 tons by 2010. In the future, the manufacturers expect to extend business to mass-production cars, saying that their next goal is to develop technologies that can produce carbon fiber in large quantities and at low prices. Thus, we can look forward in near future to have eco-friendly family cars made up of carbon fiber from renewable sources with all desired qualities like good looking, light weight, fuel-efficient, strong enough and cost-effective. |
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Scientists funded by the European Space Agency have measured the gravitational equivalent of a magnetic field for the first time in a laboratory. Under certain special conditions the effect is much larger than expected from general relativity and could help physicists to make a significant step towards the long-sought-after quantum theory of gravity. Just as a moving electrical charge creates a magnetic field, so a moving mass generates a gravitomagnetic field. According to Einstein’s Theory of General Relativity, the effect is virtually negligible. However, Martin Tajmar, ARC Seibersdorf Research GmbH, Austria; Clovis de Matos, ESA-HQ, Paris; and colleagues have measured the effect in a laboratory. Their experiment involves a ring of superconducting material rotating up to 6 500 times a minute. Superconductors are special materials that lose all electrical resistance at a certain temperature. Spinning superconductors produce a weak magnetic field, the so-called London moment. The new experiment tests a conjecture by Tajmar and de Matos that explains the difference between high-precision mass measurements of Cooper-pairs (the current carriers in superconductors) and their prediction via quantum theory. They have discovered that this anomaly could be explained by the appearance of a gravitomagnetic field in the spinning superconductor (This effect has been named the Gravitomagnetic London Moment by analogy with its magnetic counterpart). |
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THIS UNIVERSE Since the speed and path of the light is unaltered by the motion of the source, then why don’t we see the light bend, since our own universe is in motion? The theory of relativity does not abolish dynamics or conservation of energy momentum. Speed of light is the same in all frames of reference but other things change to ensure that laws of dynamics are not broken. One does different transformations in going from one frame of reference to another. The direction of light would look different in different frames of reference — also its colour, or the energy of its photons. Light is also bent by gravitation. One of tests proposed for the general theory of relativity was to quantitatively compare the prediction in this regard with observation. This bending is now beginning to be utilised for detecting a host of astronomical phenomenon through gravitational lensing. The point is that any- thing that can bend light in a predictable way can also be used for making a lens which is but a device that can be employed for concentrating (or diverging) light from a source to produce an image. Just to give a common example consider the decay of a neutral pi meson (the pion). In the rest frame of the pion the two photons into which it decays go in opposite direction so that the net momentum remains the same i.e. zero. On the other hand the angle between the two photons in the laboratory frame would depend on the energy of the pion and the angle at which the photons were emitted in the pion rest frame. Indeed the measurement of this angle is used to estimate the energy of the pion in the laboratory frame. I’ve often noticed that when I’m working on my computer and I place a finger between the computer screen and my eyes I see double images of my finger, that are somewhat translucent. How does it happen? The observation arises from the fact that you are blessed with two eyes. Close one of your eyes and you would see only one image and it will not be translucent. When you focus your eyes on the screen the brain takes the two images seen by the two eyes and combines into one picture. But then it cannot simultaneously combine the images from an intermediate object on which it is not focused. So you see two images and they are displaced from each other. The line from your eye to the finger is different for the two eyes because the eyes are separated from each other. The translucence of the images comes from the fact that the light of the screen coming in the direction of one eye is not so obstructed for the other eye. You would also notice that when you close one eye and then the other, the image shifts. This is called parallax. Modern cameras use this to determine the distance to the object and automatically adjust the focus of the lens.
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Trends Analyses of the gases dissolved in water trapped in
ancient minerals suggest that methane-generating microbes have been
around almost 3.5 billion years, more than 700 million years longer
than previous geologic evidence had indicated. Because methane prevents the loss of heat from Earth, the gas generated by those microbes could explain how the planet kept warm during the Archaean era even though the sun then produced less than three-fourths the radiation that it does today. Although methane produced via one method is chemically indistinguishable from that produced by the others, the ratio of carbon isotopes found in a sample of methane provides a clue to its source, says Yuichiro Ueno, a geochemist at the Tokyo Institute of Technology in Yokohama, Japan. Methane from biological sources contains less carbon-13 than does methane from nonbiological sources. Flowing nano ripples Some remarkable geometrical features may appear for instance on a glass surface when it is bombarded with ions, such as triangular patterns and ripples. Scientists study nano ripples and other geometrical features created by bombarding a surface with a beam of ions because of their potential as a template for growing other specific nanostructures. If they want to exploit this potential, they will first need a thorough understanding of the creation and evolution of geometrical features of this kind. Comet sampler The first study of comet dust brought to Earth by a spacecraft has revealed several minerals that could have formed only at the fiery temperatures close to the sun or another star. The findings come as a surprise because comets, frozen relics of the early solar system, were born beyond the orbit of Neptune and spend most of their time there. Don Brownlee of the University of Washington in Seattle and his colleagues base their findings on the first particles they’ve examined from the Stardust craft. Stent repair Small mesh cylinders called stents, which doctors surgically implant to prop open clogged arteries, have a vexing tendency to become blocked soon after they’re inserted. Stents can be cleared, but the only approved treatment for keeping a bare-metal stent from clogging again is the application of radiation directly inside the blood vessel. Two U.S. studies now find that inserting a new, drug-coated stent inside the old one — like a sleeve inside a sleeve — keeps blood flowing better than zapping it with radiation does. |
TU Delft Researchers have shed new light on the formation of nanoscale surface features, such as nano ripples. These features are important because they could be useful as templates for growing other nanostructures. The scientific journal Physical Review Letters published an article last week on the research in Delft.