A researcher for Japanese mobile communication giant NTT docomo, wears electro-oculogram (EOG) sensors during a demonstration of the advanced technology in Tokyo. By moving his eyes, he is able to control a digital music player .
Friday, July 25, 2008
Dye coating harvests more sunlight ~~>watch out ~~>>
Magic dyes: The dyes can double the efficiency of solar cells used today.
A simple sheet of glass coated with dye could be enough to cut the costs of solar power. That’s the claim from researchers who have created a ‘solar concentrator’ that harvests photons and funnels them into photovoltaic devices.
The device allows relatively small solar cells to harness rays from a much larger area.
Mirrors that track the Sun are already used to deliver extra light onto solar panels and maximize their electricity output.
But these mirrors can be costly to deploy and maintain, and the solar cell is prone to overheating. In the 1970s, scientists tried to develop alternatives that used light-absorbing dyes.
The alternative
But the research stalled because many of the dyes were unstable in sunlight, or because the photons didn’t get very far through the plastic before being reabsorbed.
Researchers led by Marc Baldo at the Massachusetts Institute of Technology in Cambridge have now come up with an alternative that uses a mixture of dye molecules in a thin film coated onto glass.
Each dye absorbs light of a different wavelength to make the most of sunlight’s spectrum.
By fine-tuning the dye mixture and adding an extra compound controls the re-emission process, ensures that most of the photons get trapped inside the glass.
The team thinks they can boost the power efficiency of a cadmium telluride cell from 9.6 per cent to 11.9 per cent, and a CIGS cell (copper-indium-gallium-selenide) from 13.1 per cent to 14.5 percent. The research is published in the journal Science.
Baldo thinks that the efficiency can still be vastly improved. “We could ultimately double the efficiency of 90 percent of solar cells used today,” he predicts.
Solar cells are very sensitive to defects in the material, but that doesn’t apply for these thin films, says Baldo. That means it could help solar cells to produce electricity at a mere $1 per watt, which is essential if the solar industry is to be economically sustainable.
Lawrence Gasman, principal analyst at NanoMarkets of Glen Allen in Virginia, is impressed that Baldo’s system seems to be so easy to manufacture, and says that commercial interest in innovations such as these is blooming.
But dye-based systems still face stiff competition from conventional concentrators.
In May, IBM claimed to have used mirrors to concentrate 230 watts of the Sun’s power onto 1 square centimetre of solar cell. This is a much higher concentration than would be possible with Baldo’s dyes.
Educating more students, the modern way~~>>the right way to go further !!!
| Videoconferencing increases the number of students who can be educated |
Wide reach: Videoconferencing technology is available and can be cost-shared among multiple institutions.
A week ago, many of us at the L V Prasad Eye Institute took part in an exciting event — a live lecture by the world-renowned glaucoma expert from Johns Hopkins University, Professor Harry Quigley. A clinician-scientist with over three decades of experience, he is also an outstanding speaker.
This was a special event since it was live and interactive. He was at Baltimore in the U.S., talking to us at 8 AM his time and we were all listening to him here in India at our local time of 1830 hours. Plus, it was not just 170 of us at Hyderabad, but also colleagues at our GMRV campus at Vizag and the BEI campus at Bhubaneswar.
Altogether, Quigley lectured to over 250 people across the globe, spread in three cities quite apart from each other. He was occasionally interrupted by the audience for clarifications and questions. And at the end of the fifty-minute lecture, we had a twenty-minute question-answer session.
It was a specialized topic, namely, clinical aspects of the eye disease glaucoma in which he is an acknowledged authority.
Four major points
He distilled his talk around four major points.
One: chase the family. Glaucoma runs in families. Thus if an elderly member is brought to the clinic, check the accompanying family member too — even if he/she has no complaints. Precautionary steps could be started so as to prevent or take early steps. Glaucoma, the second major cause of blindness, is a ‘silent’, progressive killer of eyesight.
Second: Just do not assume that the eye pressure has to rise to 21 units. This is a myth. Intra-ocular pressure is a person-specific number, depending on several factors. It is thus important to check more details — the size of the ‘disc’, the ‘cup to disc’ ratio, corneal thickness so forth.
Third: Make sure that the patient complies with your advice and uses the drug regularly. Given that the glaucoma patient has to use drops and/or pills regularly, daily, chances of his/her getting ‘fatigued’ over this regimen are high. The doctor has to be after the patient to ensure compliance.
Fourth: Do not depend overly on the new, fancy equipment and technologies. They focus on one or two particular features or parameters. Depend more on your ‘gut feeling’. The latter comes out of the experience of having treated many patients, each an individual in his/her own right.
Cost involved
When I checked the cost involved in putting up this video-conferencing facility, with access to the four sites mentioned above, I was given the number of about two crore rupees at today’s price. Each one of us remembers a teacher or two from our school and college days, who were so good that they even changed the career we chose later.
It was my chemistry teacher at Pilani, Mr Raja Rao, who made the subject come so alive and exciting that I chose chemistry as my career.
How exciting it would be to recall many of these great teachers, request them to teach through this video-access mode on a live, interactive basis, to a large number of students!
The Quigley example
It is not just these. As the Quigley example shows, the best teachers from anywhere can be requested to teach in this mode. And if there is one thing that a good teacher loves, it is to teach and teach more — and just for the asking.
A good teacher gets as much “high” when he teaches, just as some of his more receptive students do. And they love to teach under graduates and high school students.
Long years of teaching and research make them better and better with time. Nobel Prize winners Linus Pauling of Chemistry, Richard Feynman of Physics and Salvador Luria of Biology, always wanted to teach undergraduates and did so until they reached heaven at ripe ages.
Our own Professor C.N.R. Rao loves to teach college and high school students, and they love it too.
India is set to open 8 more IITs and 16 more national universities. These are in addition to the expansion of existing ones, and about an equal number in the private sector. One major problem they face is the lack of teachers, and a dearth of good and inspiring ones at that.
The solution
What is the solution? Use technology: identify outstanding, experienced teachers who have retired from service because they turned 58/60/62 or 65, but are available and willing, and request them to teach in the video-conferencing mode.
Cost-shared
The technology is available, can be cost-shared among multiple institutions, each of which will have access to the facility. Each lecture can thus be heard by several hundred or even thousand students, who can interact with the teacher in real time, ask questions, clear doubts and benefit. As my primary school English teacher told us: Where there is a will, there is a way. And to the cell phone company’s question: “how many students can a teacher educate?” The answer is: Technology expands the limit.
China quake: topography can reveal tectonic activity~~>lets see ~~>>
| Changes in river channel steepness were seen in the area where the quake had struck |
Terrain Tales: The May 12 quake provides compelling evidence that landscapes can encode information about the rates and patterns of tectonic activity.
The May 12 earthquake that struck the Sichuan Province in China appears to indicate that topography, or more specifically, changes in landscape gradients can be used to reveal seismic hazards of a region. Geophysical methods have traditionally been used to study tectonic activity and earthquakes.
When two continental plates push against each other, as in the case of the Indian and Eurasian plates, the crust crumples, resulting in the formation of mountain ranges.
Sudden steepness
But even in such rugged mountainous regions, there can be places where the ranges suddenly become hundreds of metres steep. Tectonic geomorphology, as it is called, is based on the premise that such sudden change in gradients reflects the underlying tectonic activity.
This is particularly derived by studying the relief and elevation of bedrock-based river channel network.
Dr. Eric Kirby, in a paper published online in the Nature Geosciences journal, reported systematic changes in river channel steepness and topographic relief in the area where the quake had struck.
The anomalous steepness of the river-channel profile “coincides almost exactly with the surface trace of the Yingxiu-Beichuan fault” that ruptured on May 12, reports the paper.
Dr. Kirby is from the Department of Geosciences, Penn State University, Pennsylvania, U.S., and is the first author of the paper.
The May 12 quake provides the “most compelling evidence to date that the landscape itself encodes information about the rates and patterns of tectonic activity,” the paper states.
First observed in 2003
The sudden change in topography in the Sichuan Basin was seen by Dr. Kirby and others way back in 2003. Their findings, published in the Journal of Geophysical Research, in 2003 noted that the Yingziu-Beichuan fault was more active than the surrounding faults.
Despite reservations by those relying on traditional methods in interpreting topography to understand tectonics, the researchers insist that the May 12 event “makes clear that landscape analysis can help with initial identification of active structure.”
Global positioning system (GPS) is one of the tools used for understanding the rate at which two plates move towards each other.
But the precision of GPS is highly dependent on the nature of the measurement and the length of time that an instrument occupies a position.
Campaign mode
Though the Sichuan Province has more than 20 GPS stations that were installed in the early 1990s, the measurements were not taken continuously.
“Measurements were all conducted on a campaign mode,” Dr. Kirby noted in his email communication to this Correspondent. In a campaign mode, a marker is installed in the ground, and is measured by GPS for 24-72 hours to obtain a precise position. It is then remeasured several years later, to see how that position has changed.
Dr. Kirby notes that measurements were taken 3-4 times after they were installed in the 1990s. “As far as I am aware, there are no continuous stations in this region,” he pointed out.
The GPS had recorded that the plate convergence was occurring at a slow rate of 2 mm per year. When the lateral movement of the plates is small, the vertical motion of the crust is even smaller.
Though GPS can detect both lateral and vertical movement, it becomes challenging to detect very small movements, particularly the vertical component.
Uncertainties magnified
“It is simply difficult [for the GPS] to detect rates of vertical motion of the crust that are less than 1 mm/year,” noted Dr Kirby. And when done on a campaign mode the uncertainties become larger, and the vertical uncertainties are in the order of many centimetres.
And because GPS is not able to resolve differential vertical motions of the crust (because of large uncertainties), the geomorphic analysis provides a clue to where this is happening.
Unlike GPS that provides very precise estimates of the position at a single point where the GPS station is located, digital elevation models provide an estimate of the topography across an entire region. And this helps in identifying the seismic hazard areas.
PFBR: main vessel to be installed soon
The main vessel of the 500 MW Prototype Fast Breeder Reactor that is being constructed at Kalpakkam will be installed anytime during the second half of September, according to Dr. Baldev Raj, Director of the Indira Gandhi Centre for Atomic Research (IGCAR).
The main vessel will house some of the main components of the reactor, like the grid plate (on which the subassemblies containing the fuel will be placed), core support structure, and the primary pipes that will bring the coolant to the grid plate.
Fast breeder reactors have three vessels — the innermost is the inner vessel where the sodium coolant is present, followed by the main vessel and finally the safety vessel. The safety vessel is the outermost vessel. The safety vessel is to contain the sodium coolant in case of any leak in the main vessel.
The main vessel is about 13 metres in diameter, 13 metres in height and about 25 mm in thickness. The small thickness is sufficient because it has to only bear the weight of the coolant (1150 tonnes) and other structures (about 700 tonnes). Also, the pressure inside the main vessel will be low.
This is because the fast breeder reactor uses liquid sodium as a coolant. Sodium becomes liquid at about 100 degree C, and being a metal, the heat transfer property is very good.
Robots for checking
The PFBR reactor is designed to have a gap of 30 cm between the main vessel and safety vessel. “This gap is required for checking the health of the main and safety vessels,” said Dr. Raj.
Highly mechanised robots will be used to check the vessels for any signs of a crack in the vessels through which the sodium can leak. The robots will not be a permanent part of the reactor but will be lowered as and when required. “These must be one of the high tech robots developed in the country,” he said.
Scientists to explore Russia’s Lake Baikal
Russian scientists recently outlined plans for a submarine expedition this month that will for the first time probe the depths of Lake Baikal, a unique ecosystem and the deepest lake in the world.
The expedition is being organised by Artur Chilingarov, a pro-Kremlin member of parliament and an Arctic explorer who led the team of scientists that planted a flag at the bottom of the North Pole in August last year.
“It’s technically very complex,” Chilingarov told reporters in Moscow, explaining that the bottom of Lake Baikal at 1,600 metres (5,249 feet) has never been explored, with previous missions only going down hundreds of metres.
Scientists will collect samples at different depths and hope to document the effects of global warming on the lake, as well as drawing the attention of the Russian government to the need for greater environmental protection.
The mission to Lake Baikal — a UN World Heritage site — will begin on July 29 and will carry out dozens of dives by the Mir-1 and Mir-2 mini-submarines. The mission is being funded by environmental organisations.
Lake Baikal contains around a fifth of the world’s freshwater reserves.
Extraordinary finding of fossilised animals
Extraordinary finding of fossilised animals
Fossilized jaw of a crocodile is displayed at the Smithsonian Research Institute in Panama City. More than 500 fossils of various animals that lived before a land bridge linked North and South America were uncovered recently.
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