SCIENCE & TECHNOLOGY



Metal fuel
S.S.Verma

C
heap
and constant availability of fuel is a major concern of present-day civilisation. Different efforts are being directed in this direction with a rising concern about environmental degradation also. Rocketing fuel prices, pollution-choked streets and global warming could change the relationship between transportation and mankind in coming times.

Dino discoveries galore
I
t
has been a wonderful season for dinosaur enthusiasts. New discoveries as far apart as China, South Africa and Spain have put some meaningful flesh on the fossilised bones of the biggest-ever beasts to walk the land. With each new discovery, dinosaurs are becoming a little less mysterious than they once seemed.

THIS UNIVERSE 
PROF YASH PAL

Prof Yash Pal

Prof Yash Pal



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Metal fuel
S.S.Verma

Cheap and constant availability of fuel is a major concern of present-day civilisation. Different efforts are being directed in this direction with a rising concern about environmental degradation also. Rocketing fuel prices, pollution-choked streets and global warming could change the relationship between transportation and mankind in coming times.

People have already experienced importance of concentrates in items like soap, paste, washing powder etc. and it will be of great importance if such concentrates become available in terms of fuels that fulfill qualities like production of more energy with small amount, cost-effective, easy availability and environmental friendly and will prove to be the fuel of the future. Metal nano-particles are the promising candidates in this direction.

Researcher at Oak Ridge National Laboratory in Tennessee (USA), have come up with a plan to transform the way we fuel engines. Chunks of metal such as iron, aluminium or boron are the thing, they believe can be used as fuels by turning them into powder with grains just nanometres across and the stuff becomes highly reactive. On ignitition it will release copious quantities of energy.

With a modified engine and a tankful of metal, they predict that an average saloon car could travel three times as far as the equivalent petrol-powered vehicle. Better still, because of the way that this metal nano-fuel burns, it is almost completely non-polluting. That means no carbon dioxide, no dust, no soot and no nitrogen oxides.

Whatís more, this fuel is fully rechargeable as spent nanoparticles can be treated with a little hydrogen or something else and the stuff can be burnt again and again. It could spell the start of a new fuel age. All kinds of engines, from domestic heating units to the turbines in power stations, could be adapted to burn metal.

Burning a heap of powdered metal (e.g. iron) releases almost twice as much energy as the same volume of petrol, and replacing iron with boron gives five times as much. When granules of metals such as iron and aluminium come into contact with air, they become coated with a layer of oxide that must be removed before the metal can ignite. To kick off combustion in most metals, we need a heat source with a temperature of at least 2000oC, which is high enough to vaporise the oxide layer and expose the bare, reactive metal beneath. That might be fine for a rocket but itís not so simple for an automobile engine.

Another problem is that once the vapourised metal oxide starts to cool, it solidifies and forms ash. High temperatures and clouds of ash present no problems in a oneshot rocket but they create a serious mess for anyone trying to burn metal powder in an internal combustion engine.

The writer is from the Department of Physics, S.L.I.E.T., Longowal
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Dino discoveries galore

It has been a wonderful season for dinosaur enthusiasts. New discoveries as far apart as China, South Africa and Spain have put some meaningful flesh on the fossilised bones of the biggest-ever beasts to walk the land. With each new discovery, dinosaurs are becoming a little less mysterious than they once seemed.

Chinese scientists have led the way with a series of stunning finds, such as the discovery of a giant bird-like creature that walked on two legs, weighed more than a ton and was armed with dagger-like claws and a bone-crushingly large beak.

Twice as tall as a man, Gigantoraptor was the stuff of nightmares. Its fearsome head and parrot-like beak sat on a muscular, elongated neck. Its body was also covered in feathers, underscoring the growing realisation that modern birds are almost certainly the living descendants of dinosaurs.

The announcement of Gigantoraptorís discovery in the Gobi desert of inner Mongolia came just a day after another team of researchers said that they had identified the remains of a new species of mini-dinosaur found in South Africa. It turned out that creature was related to two of the lumbering vegetarians of the dinosaur world ó Stegosaurus and Triceratops ó which are famous for their armour-plated skin and horny protective ruffs.

ó The Independent, London
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THIS UNIVERSE 
PROF YASH PAL

After dark matter, please tell us about dark energy

I find the letters from young enthusiastic readers keep challenging me beyond my capability and understanding. I often have the temptation to be utterly truthful and give up after confessing my ignorance. I happened to be present at a lecture when evidence for existence of such a diabolic thing like dark energy was unveiled. Some supernovae at the edge of the universe seemed to be moving away much faster than the rate of expansion of the universe.

One of the methods used for determining the rate of expansion of the universe is to explore the relation between the red shift of astronomical objects and their distance. It is clear that we would have a handle on the distance of a distant object if it were assumed to be a standard candle and its brightness was measured. The rate at which it is receding from us would be know from the red shift of its lines. A class of supernovae has been used to provide the standard candles in this regard. It has been observed that some of the supernovae with large red shifts appear to be too dim to be at the distance indicated by their red shifts if use the standard value of the hubble constant. This has been interpreted as indicating the the universe has started to expand much faster than expected; this then is taken as an indicator of a large repulsive force embedded in the underlying fabric of the universe. The energy associated with this force is the so-called dark energy!

I cannot help being a little skeptical. Do we have enough confidence that the few supernovae we have used are truly standard light sources? Are we sure that the dimness of the sources is not due to absorption of their light by intervening dust clouds? Perhaps these doubts would be removed in time.

However one is still left with a feeling that parameters are being chosen, somewhat arbitrarily, to make the universe completely consistent with the dominant model of big bang cosmology.

We might end up getting a good parametric fit without a solid physical foundation. That would be, at best, some tentative progress, not a proper understanding.

You also asked me whether dark matter and dark energy have anything to do with each other. I am sure that at some deep level, which would perhaps appear as a rudimentary obvious level when we have understood it all, they must be connected.

They are both connected with gravitation and the general fabric of the universe. Universe cannot be a hotchpotch of stuff thrown in by unthinking nature. Is has to be the only possible universe. If so dark matter and dark energy would naturally require each other, as would all the other things, including curious children and old scientists struggling to answer their questions.
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