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Water Filtration System in a Straw

LifeStraw makes previously contaminated water drinkable by removing bacteria and viruses

 
LIFESTRAW: is a mobile personal filtration system containing filters that make water teaming with typhoid-, cholera- and diarrhea-causing microorganisms drinkable.
Courtesy of The Vestergaard Frandsen Group

Sometimes, it's the simplest technologies that have the greatest potential impact on people's lives. Take the Vestergaard Frandsen Group's mobile personal filtration system, otherwise known as LifeStraw. It is a powder-blue plastic tube—much thicker than an ordinary straw—containing filters that make water teeming with typhoid-, cholera- and diarrhea-causing microorganisms drinkable.

The filters, made up of a halogenated resin, kill nearly 100 percent of bacteria and nearly 99 percent of the viruses that pass through LifeStraw. A University of North Carolina at Chapel Hill evaluation tested the device's performance in water containing Escherichia coli B and Enterococcus faecalis bacteria and the MS2 coliphage virus as well as iodine and silver. The results indicated that LifeStraw filtered out all contaminants to levels where they don't pose a health risk to someone drinking the water.

But the device does not filter heavy metals such as iron or fluoride nor does it remove parasites like cryptosporidium or giardia, although the Switzerland-based company's CEO, Mikkel Vestergaard Frandsen, says there is a version of LifeStraw available to relief groups in Bangladesh and India that can filter arsenic.

At less than 10 inches (25 centimeters) long, the device can filter up to 185 gallons (700 liters) of water, estimated to be about a year's supply for one person. The device is no longer usable when its filters become too clogged to pass water through, typically after a year of hard use.

The success of the personal filtration system led Vestergaard Frandsen to introduce earlier this month its LifeStraw Family device, an instant microbiological purifier that provides about 2.6 gallons (10 liters) of safe drinking water in an hour and about 4,000 gallons (15,000 liters) over its life span for a family of six. LifeStraw Family is designed to sieve dirt, parasites, bacteria and viruses, and will be available starting in May.

The next step is promoting LifeStraw technology so that nongovernmental organizations (NGOs) and aid groups will buy and distribute them. This is no small task, given that the need for clean water is not promoted as heavily as AIDS prevention or literacy training in some developing countries, Frandsen says, adding, "No one is stepping forward to be the rock star of diarrhea [eradication]."

But LifeStraw was recognized by Saatchi & Saatchi's public relations arm as the top "world-changing idea" in a recent competition of technologies impacting medicine, education and aid work. Vestergaard Frandsen Group received $50,000 from Saatchi, plus another $50,000 worth of the PR firm's marketing services.

Saatchi, which is owned by France's Publicis Groupe, SA, chose LifeStraw over a field of competitors that included a reusable controller to improve the distribution of IV fluids, a collapsible wheel that can be folded down for easier storage when not in use on bicycles or wheelchairs, an energy-efficient laptop designed for children in developing countries, a 3-D display that uses special optics and software to project a hologramlike image of patient anatomy for cancer treatment, an inkjet printing system for fabricating tissue scaffolds on which cells can be grown, a visual prosthesis for bypassing a diseased or damaged eye and sending signals directly to the brain, books with embedded sound tracks to help educate illiterate adults on health issues, a phone that provides telecommunications coverage to poor rural populations in developing countries, and a brain-computer interface designed to help paralyzed people communicate via neural signals.

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Energy storage nears its day in the sun

Photo 
Solar panels in a file photo. Energy storage is an unglamorous pillar of an expected revolution to clean up the world's energy supply but will soon vie for investors attention with more alluring sources of energy like solar panels, manufacturers say.

Energy storage is an unglamorous pillar of an expected revolution to clean up the world's energy supply but will soon vie for investors attention with more alluring sources of energy like solar panels, manufacturers say.

"It's been in the background until now. It's not sexy. It's the enabler, not a source of energy," said Tim Hennessy, chief executive of Canadian battery makers VRB Power, speaking on the sidelines of a "CleanEquity" technologies conference in Monaco.

VRB will start mass production this year of a longer-lasting rival to the lead acid battery currently used to store energy for example produced by solar panel, Hennessy said.

Low carbon-emitting renewable energy is in vogue, driven by fears over climate change, spiraling oil prices and fears over energy supply and security.

While the supply of the wind and sun far exceeds humanity's needs it doesn't necessarily match the time when people need it: the sun may not be shining nor the wind blowing when we need to cook dinner or have a shower.

Soaring production of solar panel and wind turbines is now spurring a race to develop the winning energy storage technologies which will drive the electric cars and appliances of the future.

The race is heating up as manufacturers with entirely different solutions near the moment of commercial production.

For example, UK-based ITM Power sees the future of energy storage in the explosive gas hydrogen. The company is developing a piece of kit called an electrolyzer which uses solar or wind power to split water into hydrogen and oxygen.

The hydrogen is then stored in a pressurized container until it is needed, whether to drive a car, produce electricity or for cooking.

"With batteries you're taking enormous quantities of basic raw materials," said Chief Executive Jim Heathcote, referring to cadmium in nickel cadmium varieties. His company won an award for research at the Monaco conference, organized by corporate finance advisers Innovator Capital.

"Two things we're confident of is the supply of renewable energy and water," he said.

ITM Power aims to start production later this year of electrolyzers and next year of hydrogen fuel cells which generate electricity.

"The one problem everyone's had is how to store. The ability to take (surplus) renewable energy and make useful fuel out of it is almost priceless," Heathcote said.

RICH

The economic opportunities are highlighted by a third company, U.S.-based EnerDel, which aims to supply batteries for the "Th!nk City" electric vehicle, manufactured by Norway's Think Global.

In the case of electric cars, cheap, lightweight batteries are needed to power motors, and will eliminate carbon emissions if the batteries are charged using renewable power sources.

EnerDel has patented a lithium-ion battery which it says is lighter and cheaper than the nickel metal hydride batteries currently used in hybrid electric cars such as the Toyota Prius.

"I think energy storage is the next frontier," said Charles Gassenheimer, chairman of EnerDel's owners Ener1 Inc.

The "Th!nk" car could be the world's first mass production electric vehicle, starting in earnest in 2009. It will go from 0 to 60 miles an hour in about 8 seconds and have a range of up to 100 miles, said Gassenheimer.

Investors have given their thumbs up to Ener1, which now has a market capitalization of around $700 million, a ten-fold increase over two years ago.

Scientists Tuning Very Large Array Radio Telescope for Deeper Exploration

The NSF's Very Large Array radio telescope is getting a digital makeover that will give it the sensitivity to pick up a cell phone signal on Jupiter, and to probe deeper into outer space

 
SILENT VIGIL: The NSF's Very Large Array (VLA) radio telescope has become the Expanded VLA and will be 10 times more powerful when work is completed in 2012.

 
EYES TO THE SKIES: The NSA is upgrading each antenna so it can collect eight simultaneous data streams at about two GHz, up from the previous capability of four data streams at about 50 MHz.

 
AWESOME ARRAY: Construction on the EVLA began in 2001, at an estimated cost of about $93.8 million.

 
MAKEOVER: The VLA's field of 28, 230-ton dish antennas--each 82 feet (25 meters) in diameter--are being converted to use state-of-the-art digital electronics, including a fiber-optic system replacing the older waveguide system.

 
HIGH AND DRY IN THE ANDES: The Atacama Large Millimeter / submillimeter Array (ALMA) will be installed by 2012 in northern Chile's Atacama Desert, at an altitude of 16,500 feet (5,000 meters).

 
SUPERNOVA: A VLA image of the region surrounding the W30 supernova remnant located in the Milky Way. The image was created to look for new supernova remnants through their nonthermal radio emission.

 
THE SUN: This VLA image shows the full disk of the Sun at a frequency of 4.6 GHz. The brightest features (red) have a temperature of one million degrees and show where very strong magnetic fields exist in the sun's atmosphere.

The National Science Foundation (NSF) is in the process of transforming its Very Large Array radio telescope into the—wait for it—Expanded Very Large Array, thanks to digital technology that will boost the Socorro, N.M., facility's already impressive ability to tune in on black holes, supernovae and the rest of the deep space menagerie.

Half of the Very Large Array's (VLA) 28 dish antennas—each weighing 230 tons—have already been upgraded so it can collect eight simultaneous data streams at about two giga- (billion) hertz, up from the previous capability of four data streams at about 50 mega- (million) hertz. The rest of the 28 antennas—which made their debut on the silver screen in the 1997 movie Contact, starring Jodie Foster and based on the eponymous Carl Sagan sci-fi novel—will go digital by 2012, increasing the facility's power 10-fold. The makeover will also replace original components that had been in operation since it was built in the 1970s.

"Certain objects radiate over a wide range of frequency," says Mark McKinnon, project manager for the Expanded VLA. "Improving the sensitivity of the telescope boils down to its bandwidth."

Completed in 1980 but operational before then, the VLA was behind the discoveries of water ice on Mercury; the complex region surrounding Sagittarius A*, the black hole at the core of the Milky Way galaxy; and it helped astronomers identify a distant galaxy already pumping out stars less than a billion years after the big bang.

The increased sensitivity and improved resolution of the EVLA will let scientists peer deep into star-forming clouds and spy on protoplanetary disks of dense gas surrounding young stars as well as track supernovae, fast-moving neutron stars and black holes, McKinnon says. The EVLA's receiving system will be sensitive enough to detect the weak radio transmission from a cell phone at the distance of Jupiter—half a billion miles away—at a projected cost of $94 million.

Data gathered by all 28 of the 82-foot- (25-meter-) diameter dish antennas are brought to a correlator—a central, special-purpose computer—which merges the input into a form that allows scientists to produce detailed, high-quality images of the astronomical objects under investigation. A new fiber-optic system replaces the older waveguide system for taking data collected by the receivers to the central control building and increases the amount of data that can be delivered from the antenna to the new $17-million correlator being built by Canadian scientists and engineers to handle the increased data flow.

In addition to its work for the NSF, the VLA site is also playing an important role in the development of another radio telescope, the Atacama Large Millimeter / submillimeter Array (ALMA). Started in 2003 and scheduled to be completed by 2012 in northern Chile's Atacama Desert at 16,500 feet (5,000 meters) above sea level, the facility employs more than 64 40-foot (12-meter) antennas. Scientists have been using the VLA site to test the performance of the dishes before they are installed at ALMA.

"The observations we make with the EVLA will be complementary with what they do at ALMA and at other radio telescopes," McKinnon adds. "Trying to understand astrophysical phenomena requires a multiwavelength approach."

Is China's Great Wall Visible from Space?

Though it stretches for some 4,500 miles, the ancient Chinese fortification is not as visible from orbit as modern desert roads

 

Choose a legend: The Great Wall of China is the one of the few man-made structures visible from orbit. Or, more remarkably, it's the only human artifact on Earth visible from the moon. Both are false, say astronauts and remote-sensing specialists. Although the Great Wall spans some 4,500 miles (7,200 kilometers), it's constructed from materials that make it difficult to discern from space.

The unglamorous truth is that the wall is only visible from low orbit under a specific set of weather and lighting conditions. And many other structures that are less spectacular from an earthly vantage point—desert roads, for example—appear more prominent from an orbital perspective.

Misinformation about the barrier's visibility dates back decades. A 1932 Ripley's Believe It or Not! cartoon claimed that the wall is "the mightiest work of man, the only one that would be visible to the human eye from the moon." The belief persisted into the Space Age. Since Neil Armstrong returned from the moon in 1969, he has been repeatedly asked whether he could see it.

His answer was relayed in a recent NASA Johnson Space Center oral history: He saw continents, lakes and splotches of white on blue. But he could not make out any man-made structures from the lunar surface, which averages a distance of 230,000 miles (370,000 kilometers) from Earth.

So just how visible is the Great Wall from low Earth orbit, at an altitude that begins around 100 miles (160 kilometers) up? Not very. Although sections near Beijing, China's capital, have been restored for tourists, in many areas the structure is crumbling. Where it still stands, the wall's mixture of stone and clay blends into the surrounding land.

"I have spent a lot of time looking at the Earth from space, including numerous flights over China, and I never saw the wall," asserts former NASA astronaut Jeffrey Hoffman, who flew on five space shuttle missions from 1985 to 1996. "The problem is that the human eye is most sensitive to contrast, and the color of the wall is not that different from the ground on either side of it."

Hoffman, now an aerospace engineering professor at the Massachusetts Institute of Technology, failed to make out the Egyptian pyramids for the same reason. But he could identify roads, airport runways and irrigation ditches simply because they stood out in their environments.

Some U.S. astronauts, notably Eugene Cernan and Ed Lu, have said they've seen the wall from low orbit. But it tends to show up only in certain lighting conditions. When the sun is low on the horizon, for example, the wall casts extended shadows that make it possible to discern its silhouette.

In 2004 American astronaut Leroy Chiao snapped a photo from the International Space Station of a swath of Inner Mongolia, around 200 miles (320 kilometers) north of Beijing, while the sun's angle was favorable. NASA experts later confirmed that the photo appears to show the wall. But Chiao admitted that he wasn't sure what he was seeing from space.

Machines can do a better job. Low-orbit satellites have sensors that can penetrate through haze and clouds, making it easier for them to produce clear images. But, as with the naked eye, identifying the wall is hardly a guarantee.

Moderate-resolution satellites, like the U.S. Geological Survey's (USGS) two operating Landsat land observation satellites that orbit 438 miles (705 kilometers) above Earth's surface, can typically only pick up the structure under specific weather conditions, says Ronald Beck, program information specialist with the USGS's Land Remote Sensing Program. "We have satellite images where snow covers the fields near the wall and snow has been cleared on the wall, and that allows us to see the wall," Beck says. "The key is contrast."

Often, identifying the rampart in satellite images requires a degree of sleuth work. In populated areas, Beck says, USGS scientists pinpoint sections of the wall by looking for parking lots and pathways. In more remote areas, they may scan for breaks in the vegetation surrounding the structure. But those techniques are hardly foolproof; at many points, the vegetation grows up and over the wall.

For the Chinese, the wall's visibility from space has long been a point of pride. When "taikonaut" Yang Liwei, China's first man in space, returned from the 14-orbit Shenzhou 5 mission in 2003 and admitted to reporters that he had not seen the Great Wall, online forums exploded with disappointment. The Ministry of Education even moved to revise its elementary school textbooks, which had long claimed the ancient barricade was visible.

Since then, a debate has raged in China, with scholars grasping at evidence that might settle the question of how great the wall really is. Chinese Academy of the Sciences Institute of Remote Sensing Application professor Wei Chengjie, who appeared on a national television special devoted to the issue in 2006, says more research is needed. "We need to carry out more tests and improve astronaut training. Some astronauts have said that they didn't see it, but that doesn't mean it isn't there. A shuttle passes by so quickly."

In the meantime, however, China's search for clarity is coming up against a modern complication. As the country industrializes and its factories belch out noxious gases, the wall further fades from view. "The biggest problem nowadays is the pall of pollution which exists over much of China," Hoffman says. "It effectively makes it impossible to see almost anything."

Dark Side of Solar Cells Brightens

A life cycle analysis proves that solar cells are cleaner than conventional fossil fuel power generation

solar-photovoltaic-array 
SUNNY DAY: Even accounting for all the energy--and pollution--involved in the manufacture of photovoltaic cells, they still produce less pollution over their lifecycle than other alternatives.

It takes power to make power—even with a solar grand plan. From the mining of quartz sand to the coating with ethylene-vinyl acetate, manufacturing a photovoltaic (PV) solar cell requires energy—most often derived from the burning of fossil fuels. But a new analysis finds that even accounting for all the energy and waste involved, PV power would cut air pollution—including the greenhouse gases that cause climate change—by nearly 90 percent if it replaced fossil fuels.

Environmental engineer Vasilis Fthenakis, a senior scientist at Brookhaven National Laboratory in Upton, N.Y., and his colleagues examined the four most common types of PV cells: multicrystalline silicon, monocrystalline silicon, ribbon silicon and thin-film. (Other contenders, such as amorphous silicon or
superefficient multijunction cells were excluded for lack of data or lack of widespread application to date.) Even taking into account the low efficiency of thin-film solar cells or the energy needed to purify silicon for the other types of PV, all proved to entail significantly fewer emissions in their entire life cycle than the fossil fuels needed to produce an equivalent amount of electricity.

In fact, most of their dirty side derived from the indirect emissions of the
coal-burning power plants or other fossil fuels used to generate the electricity for PV manufacturing facilities.

These four types of solar cells pay back the energy involved in their manufacture in one to three years, according to an earlier analysis by the same team. And even the most energy-intensive to produce—monocrystalline silicate cells with the highest energy conversion efficiency of 14 percent—emit just 55 grams (1.9 ounces) of globe warming pollution per kilowatt-hour—a fraction of the near one kilogram (2.2 pounds) of greenhouse gases emitted by a coal-fired power plant per kilowatt-hour.

Even though thin-film solar PVs employ heavy metals such as cadmium recovered from mining slimes, the overall toxic emissions are "90 to 300 times lower than those from coal power plants," the researchers write in Environmental Science & Technology.

The energy benefits of solar photovoltaics will only improve as the technology continues to
boost its efficiency at converting sunlight to electricity or proves to last longer than the 30 years anticipated by manufacturers. "There is no reason for this not to last a lot more than 30 years," Fthenakis says.

If
solar energy begins to power its own production—a so-called PV breeder cycle, in which PV-generated electricity goes to produce more PV cells—the outlook is even sunnier. "I think 30 percent of the energy consumption in the [manufacturing] facilities is easily met from the land they have available [on] the roof and in the parking lot," Fthenakis says.

And, as Fthenakis and colleagues argued in a
recent article in Scientific American, if storage technologies such as compressed air improve, then PV could provide the majority of electricity needs in the U.S. "With storage," Fthenakis says, "it is feasible to go to 100 percent."

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