New Technology for Cheaper, More Efficient Solar Cells !!

The sun provides more than enough energy for all our needs, if only we could harness it cheaply and efficiently. Solar energy could provide a clean alternative to fossil fuels, but the high cost of solar cells has been a major barrier to their widespread use.

Stanford researchers have found that adding a single layer of organic molecules to a solar cell can increase its efficiency three-fold and could lead to cheaper, more efficient solar panels. Their results were published online in ACS Nano on Feb. 7.

Professor of chemical engineering Stacey Bent first became interested in a new kind of solar technology two years ago. These solar cells used tiny particles of semiconductors called "quantum dots." Quantum dot solar cells are cheaper to produce than traditional ones, as they can be made using simple chemical reactions. But despite their promise, they lagged well behind existing solar cells in efficiency.

"I wondered if we could use our knowledge of chemistry to improve their efficiency," Bent said. If she could do that, the reduced cost of these solar cells could lead to mass adoption of the technology.

Bent discussed her research on Feb. 20, at the annual meeting of the American Association for the Advancement of Science in Washington, D.C.

In principle, quantum dot cells can reach much higher efficiency, Bent said, because of a fundamental limitation of traditional solar cells.

Solar cells work by using energy from the sun to excite electrons. The excited electrons jump from a lower energy level to a higher one, leaving behind a "hole" where the electron used to be. Solar cells use a semiconductor to pull an electron in one direction, and another material to pull the hole in the other direction. This flow of electron and hole in different directions leads to an electric current.

But it takes a certain minimum energy to fully separate the electron and the hole. The amount of energy required is specific to different materials and affects what color, or wavelength, of light the material best absorbs. Silicon is commonly used to make solar cells because the energy required to excite its electrons corresponds closely to the wavelength of visible light.

But solar cells made of a single material have a maximum efficiency of about 31 percent, a limitation of the fixed energy level they can absorb.

Quantum dot solar cells do not share this limitation and can in theory be far more efficient. The energy levels of electrons in quantum dot semiconductors depends on their size -- the smaller the quantum dot, the larger the energy needed to excite electrons to the next level.

So quantum dots can be tuned to absorb a certain wavelength of light just by changing their size. And they can be used to build more complex solar cells that have more than one size of quantum dot, allowing them to absorb multiple wavelengths of light.

Because of these advantages, Bent and her students have been investigating ways to improve the efficiency of quantum dot solar cells, along with associate Professor Michael McGehee of the department of Materials Science and Engineering.

Read More: New Technology for Cheaper, More Efficient Solar Cells

Out of Mind, out of Sight: Blinking Eyes Indicate Mind Wandering

Cognitive neuroscientist Daniel Smilek, of the University of Waterloo, studies how people pay attention -- and don't. For this study, he was inspired by brain research that shows, when the mind wanders, the parts of the brain that process external goings-on are less active. "And we thought, OK, if that's the case, maybe we'd see that the body would start to do things to prevent the brain from receiving external information," Smilek says. "The simplest thing that might happen is you might close your eyes more."

So, Smilek and his colleagues, Jonathan S.A. Carriere and J. Allan Cheyne, also of the University of Waterloo, set out to look at how often people blink when their mind wanders.

Fifteen volunteers read a passage from a book on a computer. While they read, a sensor tracked their eye movements, including blinks and what word they were looking at. At random intervals, the computer beeped and the subjects reported whether they'd been paying attention to what they were reading or whether their minds were wandering -- which included thinking about earlier parts of the text.
Source Out of Mind, out of Sight: Blinking Eyes Indicate Mind Wandering

Astronomers Release the Largest Color Image of the Sky Ever Made !!

This image provides opportunities for many new scientific discoveries in the years to come," exclaims Bob Nichol, a professor at the University of Portsmouth and Scientific Spokesperson for the SDSS-III collaboration.

The new image is at the heart of new data being released by the SDSS-III collaboration at 217th American Astronomical Society meeting in Seattle. This new SDSS-III data release, along with the previous data releases that it builds upon, gives astronomers the most comprehensive view of the night sky ever made. SDSS data have already been used to discover nearly half a billion astronomical objects, including asteroids, stars, galaxies and distant quasars. The latest, most precise positions, colors and shapes for all these objects are also being released.This is one of the biggest bounties in the history of science," says Professor Mike Blanton from New York University, who is leading the data archive work in SDSS-III. Blanton and many other scientists have been working for months preparing the release of all this data. This data will be a legacy for the ages, explains Blanton, as previous ambitious sky surveys like the Palomar Sky Survey of the 1950s are still being used today. We expect the SDSS data to have that sort of shelf life," comments Blanton. The image was started in 1998 using what was then the worlds largest digital camera a 138-megapixel imaging detector on the back of a dedicated 2.5-meter telescope at the Apache Point Observatory in New Mexico, USA. Over the last decade, the Sloan Digital Sky Survey has scanned a third of the whole sky. Now, this imaging camera is being retired, and will be part of the permanent collection at the Smithsonian in recognition of its contributions to Astronomy.

Source Astronomers Release the Largest Color Image of the Sky Ever Made

Happy New Year 2011

Happy New Year 2011

Canada is most Web-addicted nation: study

Maybe it's all those Justin Bieber fans: Canadians log more time on the Web and social media, including Facebook and YouTube, than any other nation.

The measurement company comScore reported Canada has the highest penetration of Internet access, with around 68% of Canadians routinely surfing online, against 62% in France and Britain. Close behind is 60% of Germans going online and, south of the border, 59% of Americans.

The laggards are Italians, where only 36% of the population goes online, according to comScore.

Web-addicted Canadians now spend an average 42 hours a month surfing the Web, up from 40 hours in 2009, and view an average 147 videos a month on YouTube and other online video websites.

And around 17 million Canadians, or 51% of the population, have Facebook accounts. Canada has a vibrant Twitterverse, with an estimated 5% of the traffic routinely following the world domination of homegrown pop idol Justin Bieber.

Despite Canada's broadband connectivity, Canadians still lag Americans in their embrace of so-called "smart TV." Netflix is only a recent entrant into the Canadian market, while Google TV and Apple TV have yet to break through north of the border.

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Soon, a pill may extend your life by 10 years !!

A Harvard Medical School professor believes that the day is not far when just popping a pill could make you live longer and healthier. Associate professor of Pathology David Sinclair said his work to activate the sirtuin genes, which control ageing "could expand lifespan by five to 10 healthy years."

It wouldn't stop you getting old, he said, but instead would push back the point at which you become impaired before "hopefully, (you) immediately drop dead," reports The Sydney Morning Herald. He suggested that activating the sirtuins increases memory and endurance but also slow ageing and alleviate the impact of a high-fat diet.

"If the animal studies are borne out in humans, you would have a pill for arthritis that would prevent Alzheimer's , cardiac arrest, would slow down heart disease and even protect you against cataracts," Sinclair said.

Read More: Soon, a pill may extend your life by 10 years

Birth of 'mini star' on Earth could solve energy crisis !!

In a bid to solve Earth's energy woes, scientists are contemplating building the world's first "sustainable fusion" reactor by creating what they claim is a miniature star on our planet.

Fusion is the process by which atoms combine releasing large amounts of energy – it can produce the equivalent energy of 300 gallons petrol from just a gallon of seawater and fuel equivalent of two tons of coal from 50 cups of water.

Following a series of key experiments over the last few weeks, the 2.2-billion-pound project has inched a little closer to its goal of igniting a workable fusion reaction by 2012, the 'Daily Mail' said. A team at the National Ignition Facility in Livermore, California, has fired up the 192 lasers beams at the centre of the reactor and aimed them at glass target containing tritium and deuterium gas.

The resulting release of energy was of a magnitude of 1.3 million mega joules, which was a world record and the peak radiation temperature measure at the core was approximately six million degrees Fahrenheit, say the scientists.

For a direct comparison, the temperature at the centre of the sun is 27 million degrees Fahrenheit. The scientists estimate that a prototype power station version of the fusion reactor could be operational by 2020 and that by 2050, almost a quarter of the US energy could well be supplied by fusion power.

"The results of all of these experiments are extremely encouraging . They give us great confidence that we will be able to achieve ignition conditions in deuterium-tritium fusion targets," NIF Director Ed Moses said.

Added a spokesperson for the facility : "Fusion energy is very promising as a long-term future energy source, as the fuels required to generate it are relatively abundant on Earth and the creation of energy is safe and environment friendly. A fusion power plant would be carbon free, as well as produce considerably lower amounts and less difficult-tostore radioactive byproducts than current nuclear power plants."


Read more: Birth of 'mini star' on Earth could solve energy crisis