CWL

Telescope Laser Creates an Artificial Star

What do you get when you combine one of the world’s most powerful telescopes with a powerful laser? An artificial star.

Monitoring fluctuations in brightness of a genuine bright star can indicate how the Earth’s atmosphere is changing, but many times no bright star exists in the direction where atmospheric information is needed.

Therefore, astronomers have developed the ability to create an artificial star where they need it — with a laser. Subsequent observations of the artificial laser guide star can reveal information so detailed about the blurring effects of the Earth’s atmosphere that much of this blurring can be removed by rapidly flexing the mirror.

Such adaptive optic techniques allow high-resolution ground-based observations of real stars, planets, nebulae, and the early universe. Above, a laser beam shoots out of the Keck II 10-meter telescope on Mauna Kea in Hawaii in 2002, creating an artificial star.

scinerd:

Artificial Leaf Moves Two Steps Closer to Reality

In the first, researchers led by Daniel Nocera, a chemist at the Massachusetts Institute of Technology in Cambridge, report that they’ve created an “artificial leaf” from cheap, abundant materials that splits water into molecular hydrogen (H2) and oxygen (O2), somewhat similar to the way plants carry out the first step in photosynthesis. The leaf consists of a thin, flat, three-layered silicon solar cell with catalysts bonded to both faces of the silicon. When placed in a beaker of water and exposed to sunlight, silicon absorbs photons of sunlight, generating electrons with enough energy to conduct through the silicon.

In the second study, a team led by chemists Richard Masel of Dioxide Materials in Champaign, Illinois, and Paul Kenis of the University of Illinois Urbana-Champaign, report that they’ve come up with a more energy-efficient approach to converting carbon dioxide (CO2) into carbon monoxide (CO), the first step to making a hydrocarbon fuel. Other researchers have worked for decades to devise catalysts and the right reaction conditions to carry out this conversion. But converting CO2 to CO has always required applying large electrical voltages to CO2 to make the change. That excess voltage is an energy loss, meaning it takes far more energy to make the CO than it can store in its chemical bonds.

“These papers are nice advances,” says Daniel DuBois, a chemist at Pacific Northwest National Laboratory in Richland, Washington, who works on catalysts for both splitting water and re-energizing CO2. But he cautions that neither solves all of their respective issues. The oxygen-forming catalyst in the artificial leaf, for example, remains slow, DuBois says. And the efficiency of the overall leaf is only 4.7% at most, and just 2.3% in its most simplest design. The catalyst in the CO2 system is even slower. But DuBois says that because other researchers in the field now have a good examples of systems that work, they can now focus on designing improved catalysts to speed them up.

jtotheizzoe:

You’ve seen it on TV a thousand times. When those little heart monitor machines stop going “bleep bleep” and draws a flat line, the person’s dead. Having a pulse is one of those unarguable criteria of being alive. It’s just the rules. I dare you to challenge them.

Well those rules may be about to change. Physicians at the Texas Heart Institute have created a next-generation artificial heart with no pulse. Instead of mocking the heart’s natural mechanism, this heart uses constantly spinning pump rotors to drive blood through your body.

It’s been tested in cows extensively, and now they are moving in the direction of putting it into clinical trials in humans. Just think how many love songs we’ll have to rewrite after this comes out …

(via Discover Magazine)

First practical “artificial leaf” revealed.

Scientists today claimed one of the milestones in the drive for sustainable energy — development of the first practical artificial leaf. The system is an advanced solar cell the size of a poker card that mimics photosynthesis, the process green plants use to convert sunlight and water into energy.

“A practical artificial leaf has been one of the Holy Grails of science for decades,” said Daniel Nocera, Ph.D., who led the research team. “We believe we have done it. The artificial leaf shows particular promise as an inexpensive source of electricity for homes of the poor in developing countries. Our goal is to make each home its own power station,” he said. “One can envision villages in India and Africa not long from now purchasing an affordable basic power system based on this technology.”

About the shape of a poker card but thinner, the device is fashioned from silicon, electronics and catalysts, substances that accelerate chemical reactions that otherwise would not occur, or would run slowly. Placed in a single gallon of water in a bright sunlight, the device could produce enough electricity to supply a house in a developing country with electricity for a day, Nocera said. It does so by splitting water into its two components, hydrogen and oxygen.
 
The hydrogen and oxygen gases would be stored in a fuel cell, which uses those two materials to produce electricity, located either on top of the house or beside it.