SCIENCE & TECHNOLOGY

Hydrogen storage technology
K.S. Parthasarathy
Hydrogen is a perfect fuel. It contains three times more energy than petrol. It is clean and most environmental friendly as it turns into water, after reacting with oxygen to produce energy. Hydrogen fuelled cars will not emit a cocktail of toxic fumes. They release water vapour!

Global warming evidence
Alister Doyle
Evidence that humans are to blame for global warming is rising but governments are doing too little to counter the threat, the head of the United Nations climate panel says. Rajendra Pachauri, chairman of the Intergovernmental Panel on Climate Change, also said that costs of braking climate change in coming decades might be less than forecast in the IPCC’s last report in 2001.


THIS UNIVERSE
I want to know how a proto star is formed and what are the processes that change it into a star?
The current wisdom about the formation of a star goes something like this. First you need a lot of matter, containing various elements, mostly hydrogen, along with a lot of dust that might be the result of earlier happenings in space.

Trends
Sunspot forecast
The next sunspot cycle will be 30 to 50 per cent stronger than the last one, and begin as much as a year late, according to a breakthrough forecast using a computer model of solar dynamics developed by scientists at the National Centre for Atmospheric Research in Boulder, Colo.

  • Working when resting

  • Flexible nanoskins

  • Dental implants

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Hydrogen storage technology
K.S. Parthasarathy

Hydrogen is a perfect fuel. It contains three times more energy than petrol. It is clean and most environmental friendly as it turns into water, after reacting with oxygen to produce energy. Hydrogen fuelled cars will not emit a cocktail of toxic fumes. They release water vapour!

But hydrogen is difficult to contain. It should be stored safely and efficiently and it should be easy to use. The storage methods include metal hydride storage tanks, compressed or liquid hydrogen tanks, storage in chemical compounds, carbon nanotubes, glass micro-sphere etc.

Certain combinations of metallic alloys absorb hydrogen and release it later at room temperature or at higher temperature. The total amount of hydrogen released by it is about 1-2 per cent of the weight of the tank; US Department of Energy (DOE) stipulates that to use hydrogen as an automobile fuel, the storage material should hold 6.5 per cent of their weight in hydrogen.

In May 2003, the Technology Research News (TRN) reported that researchers from the University of California at Santa Barbara, the University of Michigan, and Arizona State University identified certain relatively inexpensive organic-metal frame works which may reach the DOE prescribed goal of 6.5 per cent. They may be in the market in the next three years.

Some metal hydrides can hold hydrogen up to 5 to 7 per cent of their own weight, but at temperatures of 250 degrees or more.

According to TRN, Prof Omar Yaghi of the University of Michigan claimed that it is easy to store and retrieve hydrogen using metal-organic frame work materials. Through this process, we can insert hydrogen in to the material and then remove it reversibly with no change to the storage medium.

Hydrogen adsorption is essentially a physical process. We can stuff more hydrogen molecules in a small area. For this, you do not need low temperatures or high pressures. Prof Yaghi revealed that metal-organic frame work is unbelievably porous, with surface areas of more than 3000 square metres per gram. We can make them at high yield with cheap materials such as zinc oxide and terephthalate.

In 2005, Drs Santanu Chaudhuri and James Muckerman from the Brookhaven National Laboratory (BNL) found how titanium atoms help hydrogen atoms attach to an aluminium surface. They used titanium as a catalyst to trap hydrogen within a particular class of hydrogen storage materials.

Dr Chaudhuri conceded that their technology is at least 10 years away from being marketed as a part of hydrogen fueled cars or other mobile applications. He identified borohydrides, simple metal hydrides and carbon nanotubes-based structures as competing systems.

Do you think that their system can compete with nanofibre technology? I asked. “The sad fact is the motivation of carbon nanotubes-community to justify funding nanotubes research from many different directions. I don’t think hydrogen storage is one of the applications of nanotubes,” he asserted in an e-mail reply.

The recent US Senate Energy Bill authorises an expenditure of $ 3.7 billion over five years for hydrogen and fuel cell research to support hydrogen powered cars. The Bill quotes the claim of the US Fuel Cell Council that if just 20 percent of cars used fuel cell technology, US may cut oil imports by 1.5 million barrels daily.

Over 70 projects at universities and federal laboratories in the US receive funding to conduct basic research in the field. Sixteen nations and the European Commission along with US formed the International Partnership for the Hydrogen Economy to work together on hydrogen research. Research in the field continues to be purposeful and focused.  

— Dr K.S. Parthasarathy is former Secretary, Atomic Energy Regulatory Board

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Global warming evidence
Alister Doyle

Evidence that humans are to blame for global warming is rising but governments are doing too little to counter the threat, the head of the United Nations climate panel says.

Rajendra Pachauri, chairman of the Intergovernmental Panel on Climate Change (IPCC), also said that costs of braking climate change in coming decades might be less than forecast in the IPCC’s last report in 2001.

“If one looks at just the scientific evidence that’s been collected it’s certainly becoming far more compelling. There is no question about it,” he told Reuters of research since 2001 into a link between human emissions of greenhouse gases and rising temperatures.

Pachauri was more forthright than at the last U N climate meeting in Montreal, Canada, in December, when he declined to say whether there was clearer scientific evidence that human activities were to blame.

The last IPCC report in 2001 said there was “new and stronger evidence” that gases released by burning fossil fuels in power plants, factories and cars were warming the planet.

Warming may herald catastrophic climate changes such as more heatwaves, droughts, floods and rising sea levels.

The IPCC, grouping research by about 2,000 scientists, will present its next report to the United Nations in 2007. The report is the mainstay for environmental policy-making.

Still, Pachauri said it was too early to draw exact conclusions.

A BBC report last week said the IPCC would say in 2007 that “only” greenhouse gas emissions can explain freak weather patterns. “That’s premature because the report is still nowhere near completion,” he said. — Reuters
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THIS UNIVERSE
PROF YASH PAL

I want to know how a proto star is formed and what are the processes that change it into a star?

The current wisdom about the formation of a star goes something like this. First you need a lot of matter, containing various elements, mostly hydrogen, along with a lot of dust that might be the result of earlier happenings in space.

Large clouds of such matter are visible in many parts of our galaxy and in other galaxies in the universe. These clouds roam around, sometimes with turbulent motion, rotating and interacting with other clouds and stars. All particles in the cloud interact with each other with the force of gravity.

Fluctuations might lead to situation where the concentration of mass is greater at some point as compared to its neighborhood. This would lead to more and more particles being drawn towards that point of concentration. The big one continues to become bigger. As the particles fall in together the process accelerates.

While this is happening we have also to remember that the cloud was originally rotating, howsoever slowly. The particles that come from the direction of the axis of rotation can fall straight in towards the centre while those along the equator have to contend with the centrifugal force. Therefore, the concentration does not lead to a ball but to a disc-like shape.

All this might take millions of years. In later stages the particles falling in begin to collide with each other rather frequently and their energy becomes the chaotic energy of heat. Thus the gravitational energy being converted to heat concentrated near the centre of attraction.

This heat can already be sensed through infrared emissions. If the cloud is large enough the process can proceed towards stardom of the cloud.

Before it gets there you can call the child only a proto star. The star phase of the life begins when the interior temperature rises to several million degrees or more. At those temperatures the kinetic energies of protons and light chemical elements are high enough for thermonuclear reactions to occur; the energies of particles can overcome the electrostatic repulsion of nuclei.

Fusion of four protons to form a helium nucleus and a couple of positrons and some neutrinos can produce more energy per mass unit than any other fuel. This is the energy that ultimately enables the proto star to shine, and continue to shine till the fuel inside is exhausted. Depending on the mass of the stars that might take a few million years to many billions of years. The heavier ones shine brighter and die earlier. Our sun will still give us light and heat for several billion years.

Incidentally, let us not forget the matter around the edges of the accreting disc. It is believed that Planets are coagulated in those regions. In this picture the formation of a star has a built-in mechanism for emergence of planets around the star.

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Trends
Sunspot forecast

The next sunspot cycle will be 30 to 50 per cent stronger than the last one, and begin as much as a year late, according to a breakthrough forecast using a computer model of solar dynamics developed by scientists at the National Centre for Atmospheric Research (NCAR) in Boulder, Colo. The research results, funded by the National Science Foundation (NSF) and NASA, were published on-line on March 3 in the American Geophysical Union journal Geophysical Research Letters.

Working when resting

Physicists have long known that quantum computers have the potential to race through calculations trillions of times as fast as ordinary computers do. Now, it seems that those machines may not have to calculate at all to deliver answers.

That seemingly absurd possibility, which was advanced as a theory several years ago, has now received experimental verification. What’s more, although previous calculations indicated that such an approach would work only half the time at best, the new study suggests that it could become completely reliable.

Onur Hosten and his colleagues at the University of Illinois at Urbana-Champaign present their findings in the Feb. 23 Nature.

Flexible nanoskins

Rensselaer Polytechnic Institute scientists in Troy, N.Y., have developed a new process to make flexible, conducting “nanoskins.”

The nanoskins combine the strength and conductivity of carbon nanotubes with the flexibility of traditional polymers for a variety of applications, from electronic paper to sensors for detecting chemical and biological agents.

Dental implants

Nearly four in every 10 Indians have at least one or two of their teeth missing, necessitating an artificial tooth. But despite the latest implant techniques available in the country, most people still go in for age-old replacement techniques. Lack of trained cosmetic dentists and quacks dominating the area of dentistry have led to such a situation, specialists say.
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