SCIENCE & TECHNOLOGY

Life-saving roundabouts
H. Kishie Singh
There was a news item recently that was disturbing. Motorists in Chandigarh were bashing into the numerous roundabouts and the repair carried out on them was "making a dent in M.C. funds". Little thought had been given to the number of lives lost because of the same roundabouts.

Bendable computer screens on the way
U.S. researchers have developed a new type of semiconductor ink that brings companies a step closer to making bendable computer screens or inexpensive sensor tags to help retailers keep track of their inventory.


Prof Yash Pal
Prof Yash Pal

THIS UNIVERSE 
PROF YASH PAL

How do we arrive at the conclusion that the sun is at present in the middle of its life span and that its fuel supply will last for further 4.5 billion years ? How do we estimate the amount of remaining hydrogen present ?


 


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Life-saving roundabouts
H. Kishie Singh

Michael Schumacher hits the tyre barrier at 300 kmph and survives.
Michael Schumacher hits the tyre barrier at 300 kmph and survives.
A common scene at Chandigarh roundabouts
A common scene at Chandigarh roundabouts.

There was a news item recently that was disturbing. Motorists in Chandigarh were bashing into the numerous roundabouts and the repair carried out on them was "making a dent in M.C. funds". Little thought had been given to the number of lives lost because of the same roundabouts.

A roundabout was bashed and the City M.C came and repaired it. It was entirely possible that the same roundabout got bashed again – and again !

The Japanese have a word for addressing such a problem. "Kaizen", or "the constant improvement of the existing ability". Following this concept will lead to saving time, labour and cost, and in the case of concrete roundabouts, lives. A most precious commodity.

So why can't we have tyre walls at Chandigarhs roundabouts instead of concrete walls?

The tyres should be placed three deep in an ascending pattern and filled with mud. They will form a step of one tyre in the first step, two in the second and three in the last step. The tyres will be grouted into the tarmac. This configuration of tyres in steps and filled with mud will achieve two important functions. A car hitting the first tyre will slow the car. Should there still be a speed and momentum, the car will have to contend with a two two-tyre-high wall, and then a three-tyre high wall. This should be enough to stop the car.
Tyres of various sizes, fitted together to make a circle which should serve as a roundabout. The tyres will be grouted to the road so that they are immovable. The tyres will be filled with mud and small bushes, plants and flowers can be planted in them, but no cactus. The rubber of the tyres and the mud will act as energy absorbers and should stop a car that runs into this specially designed roundabout. Maximum damage will be to the under-carriage suspension, steering and sump. The passengers will be safe
Tyres of various sizes, fitted together to make a circle which should serve as a roundabout. The tyres will be grouted to the road so that they are immovable. The tyres will be filled with mud and small bushes, plants and flowers can be planted in them, but no cactus. The rubber of the tyres and the mud will act as energy absorbers and should stop a car that runs into this specially designed roundabout. Maximum damage will be to the under-carriage suspension, steering and sump. The passengers will be safe.
ELEVATION

Both the tyres, rubber, filled with mud are impact absorbing. Damage to the car will be minimal. Any damage will be to the undercarriage, the suspension, steering, tyres, rims and whatever is on the underside. The impact will not seep into the cabin. Even if it does most cars have air bags and every one should be wearing seat belts.

 What will have been accomplished is that the car has been brought to a halt. The occupants would be battered and bruised, but alive.

Now if the car did manage to climb over the last step of the three-step tyres, the landscaping should be conical shaped so the car has an uphill climb. More braking will be provided.

The landscaping must include small bushes which will grab the cars underside and bring it to a halt. They will grip the car and prevent it from flipping over.

Suppose the car does flip over, it will be onto small leafy shrubs and bushes. In the worst case scenario, the car lands on its roof. It will be a "soft landing". Speed has been arrested and considerably reduced. The bushes and shrubs will have to be selected with the utmost care.

The only downside to this whole exercise will be that the trees, stones and thorny cactus from the existing roundabouts will have to go. A very small price for saving lives.

In case the trees are in the centre of the roundabout, maybe they can be saved . Cut tyres in half and make a necklace of gaily painted tyres at the base of the tree. They will protect the tree and more important the car and its occupants.

Lives will be saved.

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Bendable computer screens on the way

U.S. researchers have developed a new type of semiconductor ink that brings companies a step closer to making bendable computer screens or inexpensive sensor tags to help retailers keep track of their inventory.

The discovery lies in the new material — a soluble semiconductor ink capable of carrying a negative electrical charge, said Philippe Inagaki, chief executive officer of Polyera Corp, a specialty chemicals company in Skokie, Illinois, that makes materials for flexible and printed electronics.

In the traditional silicon world there are two fundamental types of semiconductors: P-type, which carry a positive charge, and N-type, which carry a negative charge.

So far, most semiconductor inks, such as one developed by a team at Xerox Corp in 2004, have only been capable of carrying a positive charge, they said. The new ink — developed by researchers at Polyera and BASF SE unit BASF Future Business GmbH and described in the journal Nature — is an N-type.

"When you have both you make chips and circuits that are faster and more reliable and more energy-efficient. And that's a pretty big deal," Inagaki said in a telephone interview.

He said the new semiconductor ink can be printed onto flexible materials, such as a thin film of plastic or even paper, using a modified ink-jet printer. — Reuters


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THIS UNIVERSE 
PROF YASH PAL

How do we arrive at the conclusion that the sun is at present in the middle of its life span and that its fuel supply will last for further 4.5 billion years ? How do we estimate the amount of remaining hydrogen present ?

How is it possible that the sun is consuming its hydrogen at a constant rate? Is there any regulatory mechanism. Isn't it possible that all of a sudden the entire hydrogen gets fused onto helium in a very short time span and in the process, shortening its life.

I will try to answer these questions without getting into details of astronomy and astrophysics. I will pick various parts of the question in a random way starting with aspects on which there seems to be a consensus.

Firstly, there is a general acceptance of the fact that hydrogen is the dominant element in the sun, as it is in the universe at large. Hydrogen fusion, to make helium as a first step, is the primary mechanism for energy production in the sun.

How, in the present phase of solar evolution, is the rate of energy production kept in control? In other words who or what is the controlling officer to keep the solar furnace working at a constant level for such a long time? This is understood in the following manner.

The rate of hydrogen fusion is very sensitive to the energy of particles that come into collision.

The temperature at the centre of the sun determines this energy. An increase of temperature results in excessive production of energy and a consequent rise in internal pressure that balances the inward gravitational force. The excess outward force expands the sun a little, causing some cooling and combating the temperature rise and energy of the interacting particles.

The rate of energy production comes back to normal. The reverse happens when there is a decrease of the rate of fusion.

This then is the built-in feedback mechanism for control of the rate of energy production system. No supernatural power is required or considered more efficient. Indeed such natural feedback control loops are necessary in most efficient technological, and even social, systems. Because of the mechanism explained above there is no danger of the system becoming profligate and using up the fuel in excess.

Let us now turn to the question of the time period for which the marvellous solar furnace has been operating. In other word what is the present age of the sun. Here we invoke a very plausible hypothesis.

This says that the whole of the solar system must have a single origin, allowing for a spread of a few million years. We could not have had the earth and other planets without the sun. Therefore, one way of finding how long the sun has been around is to find a way of determining the age of the earth and other members of the solar system.

Fortunately we do have some reliable methods for doing that. For this we use our knowledge of life times and decay modes of some radioactive elements such as Uranium-238 (decaying into the final stable element Lead) and other radioactive isotopes such as K-40 (potassium-40). Knowing the half-life of these radionuclides, and using appropriate sites, including several meteorites, age of the solar nebula has been determined to be a little over 4.5 billion years.

This must be close to the age of the sun.

Now we come to the question about the remaining life of the sun. This is estimated by comparing the position of the sun on a diagram giving the relation between surface temperature and intrinsic luminosity of thousands of stars.

This depicts the manner in which stars evolve.

The sun seems to be right in the middle of the so-called main sequence of this diagram. It gives confidence that the sun will remain in the hydrogen burning stage for several billion years still.

After that will come the stage of a collapse followed by helium burning in the core and hydrogen burning in the outer layers.

The sun will become a red giant.

We can rest assured that one fine morning we will not wake up with an extinguished sun. There is still a lot of juice left there

Readers wanting to ask Prof Yash Pal a question can e-mail him at @@palyash.pal@gmail.com
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