SCIENCE & TECHNOLOGY

Portable explosives detector
Dr S.S.Verma
With growing terrorist we have to be more vigilant and active towards our safety. Hence, there is need of a portable, easy-to-handle and cheap explosive detector so that it can be acquired and carried by majority of people like present-day mobile revolution. This way it will be easy to detect our surroundings on our own for any threat from explosives and expert people can be informed or some other safe and suitable action can be taken for safe disposal of the explosives before any unwanted incident.

Trends
Livestock extinction
Farm scientists warned on Monday that hardy breeds of livestock vital for world food supplies were dying out across developing countries, especially in Africa, and called for the creation of regional gene banks to save them. In a report to a conference in the Swiss town of Interlaken, the experts said tough and adaptable animals were being ousted by others from richer countries that were more productive in the short-term but posed a longer-term risk for farm output.

Crushed glass on beaches
Picture a beautiful beach spanning miles of coastline, gently lapped by aqua-colored water — and sprinkled with glass.

Turbines out at sea
There is no shortage of wind in the densely-populated Netherlands but there is a shortage of space and in a nation which likes its houses small and its gardens cosy, opposition to wind farms is immense.

Prof Yash Pal
THIS UNIVERSE

Human heart is a pump. When and how does it start working?
I also want to find out when the lungs of a baby start functioning.

Prof Yash Pal

 


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Portable explosives detector
Dr S.S.Verma

With growing terrorist we have to be more vigilant and active towards our safety. Hence, there is need of a portable, easy-to-handle and cheap explosive detector so that it can be acquired and carried by majority of people like present-day mobile revolution. This way it will be easy to detect our surroundings on our own for any threat from explosives and expert people can be informed or some other safe and suitable action can be taken for safe disposal of the explosives before any unwanted incident.

Portable explosive trace detectors with comprehensive explosive detection capabilities are being developed which trace both particulates and vapours, allowing for non-invasive searches of luggage, mail, vehicles, documents and containers etc. Such explosives detectors are highly sensitive, accurate and versatile non-contact screening systems. Some latest advances towards the development of portable explosives detector are summarised here and it is hoped that the day is not far away when such a device with suitable qualities will be within reach of a common man to take care of his own safety from the terrorist attacks.

Many companies with different facilities and costs have introduced an explosives detector based on the principal of “vapour tracer system’’. This equipment can detect all types of explosives, including plastic, chemicals, and bomb-making parts as well as narcotics. Portable and light detector accurately identifies explosives and their intensity. The operation is based on the “ion trap mobility spectrometry” and can provide a detailed analysis of the explosives through the ion signal spectrum technique.

This technology, which has a high sensitivity, helps in determining the nature of the explosive content in detail. Explosives detector actually detect the chemical composition of the items that are in the machine being scanned, so item can be uniquely identified based on its chemical composition as opposed to just a simple density map (used in x-ray machines).

Efforts are being made to develop a single scanning machine that will detect explosives, weapons and drugs hidden in airport luggage. The technology can recognise about ten thousand chemical substances in seconds, as well as plastics in dangerous explosives, in around 10 seconds.

Minuscule silver wires a few nanometers across are proving to be versatile electronic components, as demonstrated recently by University of California, Berkeley, chemists who used silver nanowires as key elements of a sensitive explosives detector. The researchers made about a trillion silver nanowires - essentially nanocopic needles - and packed them tightly together in a thin layer, all needles pointing in the same direction. The layer of ordered nanowires made an ideal site for chemicals to bind for detection by a very sensitive technique called surface-enhanced Raman spectroscopy.

Many companies have come up with a cheap, mass-producible explosives detector that could be as sensitive as an optical spectrometer. This new explosives sensor technology is based on Micro Electro-Mechanical Sensors (MEMS). These microstructures are fabricated in a very similar fashion to mass produced electronic integrated circuits. MEMS can be designed as sensors for a wide diversity of physical, chemical and biological applications.

This detector uses a mechanical device that does not try to distinguish between different forms of explosives but simply warns when it touches anything that is likely to explode. The fundamental advantages of these explosive detection technologies are very low cost, extremely high sensitivity and real-time operation. A proof-of-principle prototype is currently under operation and several agencies have invested in the development of MEMS based sensor technology.

It is expected that in the times to come, portable explosive detector capable of detecting traces of plastic and high-vapour-pressure explosives - giving clear results with alarm, with easy usability and low cost will be available for a common man.

Moreover, these will be equipped with flexible power sources like rechargable DC external battery packs and AC adapter, making it convenient to use in virtually all application environments. They will be able to detect and identify minute traces of most military and commercially available explosives like C-4, TNT, Dynamite, PETN, Semtex, EGDN, DMNB, RDX, Nitroglycerine, ICAO and Taggants (DMNB, EGDN, o-MNT, p-MNT).

Future portable explosive detectors are expected to be self-contained, low-cost, lightweight, ready to use when and where needed with a minimum operation time allowing for non-invasive searches of luggage, mail, vehicles, documents and containers.
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Trends
Livestock extinction

Farm scientists warned on Monday that hardy breeds of livestock vital for world food supplies were dying out across developing countries, especially in Africa, and called for the creation of regional gene banks to save them. In a report to a conference in the Swiss town of Interlaken, the experts said tough and adaptable animals were being ousted by others from richer countries that were more productive in the short-term but posed a longer-term risk for farm output.

“There is a livestock meltdown under way across Africa, Asia and Latin America. Valuable breeds are disappearing at an alarming rate,” Carlos Sere of the International Livestock Research Institute (ILRI) told the week-long gathering. — Reuters

Smashina asbestos

An academic and industrial alliance has announced the development of world’s first device to smash asbestos into harmless pieces.

“The process is simpler and less costly than the widely practised thermal treatment method,” says the research group of the Institute of Multidisciplinary Research for Advance Materials at Tohoku University, the Redical Planet Research Institute and Sumitomo Heavy Industries Techno-Fort Company.

The airtight device is 3.8 by 3.8 by 4 metres and contains 100 iron balls each 10 centimetres across and weighing 4 kilograms.

When asbestos is put into the container, the iron balls spin around at high speed and smash the crystals of the material into decrystallised pieces.

The widely adopted method of melting asbestos in furnaces requires labour and high maintenance costs. — Kyodo

Ancient beehives

Archaeologists digging in northern Israel have discovered evidence of a 3,000-year-old beekeeping industry, including remnants of ancient honeycombs, beeswax and what they believe are the oldest intact beehives ever found.

The findings in the ruins of the city of Rehov this summer include 30 intact hives dating to around 900 B.C., archaeologist Amihai Mazar of Jerusalem’s Hebrew University told The Associated Press. He said it offers unique evidence that an advanced honey industry existed in the Holy Land at the time of the Bible.

Beekeeping was widely practiced in the ancient world, where honey was used for medicinal and religious purposes. — AP
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Crushed glass on beaches

Picture a beautiful beach spanning miles of coastline, gently lapped by aqua-colored water — and sprinkled with glass.

Ouch? Think again. It feels just like sand, but with granules that sparkle in the sunlight.

Faced with the constant erosion of Florida’s beaches, Broward County officials are exploring using recycled glass-crushed into tiny grains and mixed with regular sand — to help fill gaps.

It’s only natural, backers of the idea say, since sand is the main ingredient in glass.

“Basically, what we’re doing is taking the material and returning it back to its natural state,” said Phil Bresee, Broward’s recycling manager.

The county would become the first in the nation to combine disposal of recycled glass with bolstering beach sand reserves, Bresee said.

“You reduce waste stream that goes to our landfills and you generate materials that could be available for our beaches,” said Paden Woodruff of the state Department of Environmental Protection.

Sand is a valuable commodity in South Florida, where beach-related business generates more than $1 billion a year for Broward alone.

Sand to replenish eroded beaches is typically dredged from the ocean floor and piped to shore - about 13 million tons of it since 1970 in Broward. That’s enough sand to fill the Empire State Building more than 12 times over. — AP
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Turbines out at sea

There is no shortage of wind in the densely-populated Netherlands but there is a shortage of space and in a nation which likes its houses small and its gardens cosy, opposition to wind farms is immense.

That is why a new Dutch wind farm is being built so far out to sea it is barely visible on the horizon, reducing the visual impact of its 60 turbines to virtually nil whilst at the same time harnessing higher offshore wind speeds.

Offshore wind farms are likely to appear more and more frequently off European coastlines as governments seek to increase their use of renewable energy without angering their citizens by placing giant turbines on their doorsteps.

The 383 million euro ($522.3 million) Q7 wind park development, 14 miles from the Dutch North Sea coast, is the farthest offshore wind park anywhere in the world, and its developers Econcern and Eneco Energie say a further five to 10 such wind parks will likely follow in the next few years.

“Q7 will contribute enough electricity for 125,000 households, but it is also a learning process. We are learning how to build these wind farms, how to organise the supply chain, and how to manage and operate them,” said Bernard van Hemert, one of the wind farm’s engineering directors.

“Most campaigns against turbines are based around the noise and the visual impact, and these have been reduced by going offshore. It is more expensive to do it here than to do it on land, but we have all agreed we don’t have enough space on land,” said van Hemert.

Blessed with shallow sandy soils around their coastline, Dutch engineers say the foundations for the turbines can be hammered 82 feet into the ground in just a matter of hours, although there are myriad other challenges.

The proportions are breathtaking. The turbines extend about 320 feet from the ocean, with three sharp narrow blades, each 130 feet long. — Reuters
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THIS UNIVERSE 

Human heart is a pump. When and how does it start working?

I also want to find out when the lungs of a baby start functioning.

As you say the heart is a pump used to circulate the human blood. The blood carries nutrients and oxygen. It is necessary therefore that something like a heart should start functioning when the embryo begins to grow. The heartbeat starts very early in life; its beating heralds the beginning. It is true that the baby itself constitutes the blood that flows in embryo’s veins, but the mother provides the nutrients and oxygenation across porous membranes.

It is clear that the baby cannot breathe in the womb. One could say that its lungs might be built but they do not perform the function that they do for us after birth. That function begins with the first dramatic cry of the baby immediately after birth. It is not only the shock due to change of environment that makes the baby cry out but also its desperate attempt to gulp in some oxygen through its first breath. From then on the lungs are on permanent duty.

Coming back to the startup of heart and its function. Stopping of the heartbeat leads to death. This does happen for grownup men and women. Sometimes this is due to malfunction of the well-timed electrical impulses that control the rhythm of its beat. Here restarting can sometimes be done through electrical stimulation or shock. But if the passageways are badly blocked or the valves are badly deteriorated, such restarting attempts might fail.

Air contains 79% Nitrogen, 20% Oxygen and 1% other gases. What is the composition of gases in an air-conditioned room?

Amongst “other gases” that you have mentioned, some of the important components are carbon dioxide and water vapour. In a closed air-conditioned and inhabited room the abundance of these two is likely to change. Carbon dioxide would increase because we humans breathe and exhale. Water vapour would be less if the room were sparsely inhabited. The reason for this is that the vapour in the air we exhale would not be able to compensate for the water vapour removed by the air-conditioner. I think there will not be any other change in the relative abundance of other gases. A crowded room, on the other hand, would not be very healthy because of increase of carbon dioxide and water vapour both.


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