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Passion for solo flight Climate change worse than deforestation Trends Prof Yash
Pal THIS UNIVERSE |
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Passion for solo flight The growing attitude toward air travel in the 21st century is to strap on one’s own jet pack or rocket belt and fly over independently to any destination in order to avoid hassles and jostles of air booking, rush hour traffic to reach airport, waiting, security check and cancellations of flights. Owning a personal flying machine — of whatever type —sounds like the ultimate in freedom and mobility. Surprisingly enough, the personal flying machine has been in use successfully for over 40 years. The Hiller Flying Platform was a unique VTOL (Vertical Takeoff and Landing) machine developed back in the 1950s by Hiller Helicopter. It was a circular ducted fan unit that utilised two counter-rotating propellers. A pilot would stand on top of the unit and by leaning and shifting his body weight he could cause the platform to fly in any direction. Much of flying jetpack and rocket belt technologies development with different advantages and disadvantages was based on this unit. The most appreciable jet-pack is roughly 100” wide and 48” tall. It is powered by two 36” ducted, four-blade fans. The engine is a Rotax 503 and the fuel is premium unleaded gasoline. The maximum speed is 50 mph and its range is about 50 miles. Maximum altitude is approximately 7,000ft above sea level. It consumes three gallons of fuel per hour (it’s maximum amount of fuel you can store in it). The empty weight is about 150lbs. and its useful payload is about 205 lbs. The prototype unit is currently being redesigned and is still under development. Flight-testing will begin soon. Pricing has not yet been determined. Rocket belts/packs technology is another candidate as hydrogen peroxide rocket motors are quite simple as far as rockets go. The two shiny tanks on the backpack are both filled with Hydrogen Peroxide propellant. When the throttle is opened, high-pressure nitrogen gas (stored in the hidden middle rear tank) pushes the hydrogen peroxide propellant out and into the catalyst pack (at the very top). The propellant reacts violently with the catalyst (many tightly packed samarium nitrate coated silver screens) and instantly turns into high-pressure superheated steam at 1,370 degrees Fahrenheit. During the 35 years since the original Bell rocket belts flew, scientists and engineers have made continuous improvements in the strength-to-weight of the old standby materials; all new super strong composite materials; and materials with ever higher temperature capabilities. These innovations enabled them to create a lighter belt that could in turn carry more propellant and still be reasonably comfortable and safe for the pilot to carry on his back. This is expected to fly 50 per cent longer than the 1960s technology belts and will be fulfilling the dream of a real flying though for short air distances. One hopes that one day these technologies will allow people to fulfil their passion for solo flight in order to swoop and dive at distances comparable to a small airplane. |
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Climate change worse than deforestation
Climate change could become as big a threat to the planet’s biodiversity as deforestation by the end of the century, warn researchers. In a study published in Conservation Biology on April 11, they say a doubling in atmospheric carbondioxide could strip biodiversity-rich “hotspots” of thousands, or even tens of thousands, of species. The most vulnerable species are likely to be those living in confined geographical areas, such as mountain ranges, because of the difficulty of dispersing from these areas. “Species will be stranded with nowhere to go,” says lead researcher Jay Malcolm of the University of Toronto, Canada. “Although we usually think of the Arctic as being vulnerable, the study shows that other places where species have limited ranges — such as islands, mountains, and continent tips — are also vulnerable.” The researchers used computer simulations of future climate and vegetation to estimate the changes in habitat and associated species extinctions that would occur if carbon dioxide levels doubled over the next 100 years. Malcolm told SciDev.Net that some regions could lose up to 75 per cent of their species. The study predicts up to 9,400 extinctions from the tropical Andes, 5,750 from the Mediterranean Basin, 3,395 from the Caribbean, and 3,865 from South Africa’s Cape region. Bob Scholes, an ecologist at South Africa’s Council for Scientific and Industrial Research, says the main cause of biodiversity loss is usually assumed to be habitat loss. But, he explains, what has been missing is the understanding that climate change and habitat loss interact. “It is much harder for species to adapt to climate change by migration if the landscape is fragmented,” he says. SciDev.Net |
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Cosmic triumph THE most detailed portrait ever taken of the radiation left over from the Big Bang provides fresh evidence that the universe began with a tremendous growth spurt, expanding from subatomic scales to the size of a grapefruit in less than a trillionth of a second. In that instant, according to the theory known as inflation, microscopic fluctuations in the density of the cosmos were greatly amplified. That blueprint ultimately developed into the rich tapestry of stars and galaxies that fill the universe today. Although inflation has explained a multitude of features about the universe, before the new evidence, many details had yet to be scrutinised. Galaxy
on fire Where there’s smoke, there’s fire — even in outer space. A new infrared image from NASA’s Spitzer Space Telescope shows a burning hot galaxy whose fiery stars appear to be blowing out giant billows of smoky dust. The galaxy, called Messier 82, or the “Cigar galaxy,” was previously known to host a hotbed of young, massive stars. The new Spitzer image reveals, for the first time, the “smoke” surrounding those stellar fires. Unseen eruptions With a flash and a bang, a pellet of explosive detonates in a cavernous laboratory on the outskirts of the Pennsylvania State University campus. The explosive, triacetone triperoxide (TATP), is the one that terrorists reportedly used in their attack on the London subway in July 2005. Minutes after the lab explosion, engineers — some with bulky ear-protection gear still in place — stare at a laptop screen as they scan frame after frame of high-speed images. Beyond the flame and flying debris, the scientists focus on the ephemeral supersonic shock waves that emanate from the blast. The waves appear in the pictures as rings, ripples, or streaks. A recurrent Nova On February 12, 2006, amateur astronomers reported that a faint star in the constellation of Ophiuchus had suddenly become clearly visible in the night sky without the aid of a telescope. Speaking recently at the RAS National Astronomy Meeting at Leicester, Prof. Mike Bode of Liverpool John Moores University and Dr Tim O’Brien of Jodrell Bank Observatory presented the latest results which are shedding new light on what happens when stars explode. Records show that this so-called recurrent nova, RS Ophiuchi (RS Oph), has previously reached this level of brightness five times in the last 108 years, most recently in 1985. The latest explosion has been observed in unprecedented detail by an armada of space and ground-based telescopes. RS Oph is just over 5,000 light years away from earth. It consists of a white dwarf star (the super-dense core of a star, about the size of the earth, which has reached the end of its main hydrogen-burning phase of evolution and shed its outer layers) in close orbit with a much larger red giant star. |
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THIS UNIVERSE A new element has been found in the soil of the moon. It is said that it can be used for generating energy. What is it and how it can be used? I think you are referring to expected abundance of an isotope of helium referred to as He3 This is a form of helium that has a nucleus made up of two protons and one neutron. The abundant isotope of helium (He4) has two protons and two neutrons. He3 is not a new element. It is known but its natural abundance is very low. The abundant form of helium is obtained largely through the decay of radioactive elements and is normally recovered from gas and oil wells; most of the helium-3 on the other hand is produced by nuclear reactions using accelerators and reactors. Our sun gives us light and heat. In addition it also throws out as hot plasma a sample of ionised elements present in the photosphere. This plasma travels out at varying speeds of hundreds of kilometres per second. This is generally known as the solar wind. Like other elements on the solar surface, He3 nuclei also form a component of this wind. When the earth and the moon intercept this wind its materials can get deposited on their surface. The earth crust has been transformed radically since it was formed and the surface material has all mixed up in great volumes of material through dynamic processes involving volcanism and recycling of material. Lot of mixing has happened on the moon also because of meteorite bombardment but mixing is probably confined to a rather thin layer. It is because of arguments like this that one expects that the He3 atoms stuck in the soil of the moon might be still recoverable. While there are lot of questions about the economics of recovering close to a few megatons of He3 deposited on it during the last 4.5 billion years one has also to ask for the reason for dreaming up such an impossible task. Let us assume that we get a few megaton of He3 here on earth or even in a big box on the moon. What would we do with this? To answer this question we have to dream some more. We have to dream that we have mastered the technology of making fusion reactors. Enormous amount of work is going on in that direction and it is not inconceivable that in a few decades we might have success. A fusion reactor mimics the interacting environment going on at the centre of our sun and other stars wherein high-energy nuclei of light elements combine (fuse together) to form heavier elements; in such reactions an enormous amount of energy is released through conversion of mass into energy. (We already know how to do it when we make and test hydrogen bombs, but a bomb is not a reactor we can use for supplying energy to homes and factories). The dreamers dream that we might be able to make fusion reactors in which the nuclei that would fuse together would be He3 and deuterons. Deuterons are available in plenty. (They are the nuclei of heavy hydrogen whose nucleus contains one proton and a neutron. Abundance of heavy water in the oceans of the world is 1 part in 5000. There are a lot of deuterons on the earth). He3 and deuteron fusion is a beautiful, peaceful and non-polluting reaction in which the deuteron hands over its neutron to He3 to become a proton while He3 becomes He4, the normally abundant helium. And the process results in producing a large amount of clean energy. I hope you realise the beauty and technical challenge of this dream. It is true though that this process would also utilise the non-renewable resource of He3. |
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MAN’S passion to travel on the land and to swim in the water independently is fulfilled but he also wishes to travel independently in the air like birds. Aeroplane travel is not the real flying as that’s being carried through the air in a machine. Similarly flying with gliders and hot air balloon is also not considered as flying. 