It's all about technology

E-paper with Photonic Ink

2007-09-06T04:22:00.000-07:00

Photonic crystals are being used by a Toronto startup to create commercial devices that offer better color and resolution than other flexible displays.

By Duncan Graham-Rowe

Crystal light: Photonic crystals made out of silica beads (shown as gray balls) measuring 200 nanometers across are embedded in a spongy electroactive polymer and sandwiched between transparent electrodes. When a voltage is applied, an electrolyte fluid is drawn into the polymer composite, causing it to swell (shown as yellow in the middle image). This alters the spacing of the crystals, affecting which wavelengths of light they reflect. When the spacing is carefully controlled, the pixel can be made to reflect any color in the visible spectrum.
Credit: Nature Photonics

Scientists in Canada have used photonic crystals to create a novel type of flexible electronic-paper display. Unlike other such devices, the photonic-crystal display is the first with pixels that can be individually tuned to any color.

"You get much brighter and more-intense colors," says André Arsenault, a chemist at the University of Toronto and cofounder of Opalux, a Toronto-based company commercializing the photonic-crystal technology, called P-Ink.

Several companies, including MIT startup E Ink and French firm Nemoptic, have begun producing products with e-paper displays. E Ink's technology uses a process in which images are created by electrically controlling the movement of black or white particles within tiny microcapsules. Nemoptic's displays are based on twisting nematic liquid crystals. The benefit of such screens is that compared with traditional displays, they are much easier to view in bright sunlight and yet only use a fraction of the power.

While the quality and contrast of black-and-white e-paper displays were almost on par with real paper, color images were lacking because each pixel was limited to a single primary color. To display a range of colors, pixels must be grouped in trios. In each trio, one pixel is filtered red, another is filtered green, and the third is filtered blue. Varying the intensity of each pixel within the trio generates different colors. But Arsenault says that these old systems lack intensity. For example, if one wants to make the whole screen red, then only one-third of the pixels will actually be red.

With P-Ink, it's a different story. "We can get 100 percent of the area to be red," Arsenault says. This is because each pixel can be tuned to create any color in the visible spectrum. "That's a three-times increase in the brightness of colors," he says. "It makes a huge difference."

P-Ink works by controlling the spacing between photonic crystals, which affects the wavelengths of light they reflect. Photonic crystals are the optical equivalent of semiconductor crystals. While semiconductor crystals influence the motion of electrons, photonic crystals affect the motion of photons.

Although recently there has been a lot of research looking at using photonic crystals for anything from optical fibers to quantum computers, it's actually an ancient phenomenon. For example, photonic crystals are responsible for giving opals their iridescent appearance. "There are many organisms that have coloration that doesn't come from a dye," says Arsenault. "This is the basis of our technology."

With P-Ink, each pixel in a display consists of hundreds of silica spheres. Each of these photonic crystals is about 200 nanometers in diameter and embedded in a spongelike electroactive polymer. These materials are sandwiched between a pair of electrodes along with an electrolyte fluid. When a voltage is applied to the electrodes, the electrolyte is drawn into the polymer, causing it to expand.

The swelling pushes the silica beads apart, changing their refractive index. "As the distance between them becomes greater, the wavelengths reflected increases," says Arsenault. P-Ink is also bistable, meaning that once a pixel has been tuned to a color, it will hold that color for days without having to maintain a power source. "And the material itself is intrinsically flexible," Arsenault says.

The technology was developed with Geoffrey Ozin and Daniel Puzzo, among others, at the University of Toronto and Ian Manners at the University of Bristol, in the UK. The group demonstrated how 0.3-millimeter pixels--about the same size as many LCD displays--can independently generate a range of colors. Their results are published in the August issue of the journal Nature Photonics. "One single material can give all the necessary colors for a display without filters," says Arsenault.

In fact, by making the crystals slightly larger, it's also possible to take them beyond the visible-light range and into infrared, says Arsenault. The effects in this range would be invisible to the human eye but could be used to make smart windows that control the amount of heat that passes through them, he says.

This is a step forward, says Jacques Angele, a cofounder of Nemoptic. "The aim of these color-display technologies is to be comparable with paper. Unfortunately, the brightness of the [other technologies] today is limited to about 30 percent of paper."

"It's a spectacular innovation," says Edzer Huitema, chief technology officer of the Dutch firm Polymer Vision, based in Eindhoven. Even traditional screens, such as cathode-ray tubes, LCDs, and plasma displays, use three or even four differently colored pixels to generate color. "It's a major limitation for all color-display technologies," Huitema says. When the color of each pixel is controlled, not only does the color quality increase, but the resolution should also improve by a factor of three.

There is one display technology, however, that can tune individual pixel color, says Angele. Both Kent Displays, in Ohio, and Japanese electronics firm Fujitsu have been taking this approach, which, in essence, involves placing the three colored pixels on top of each other. But besides being technically difficult and expensive, this approach reduces the brightness of the colors, Angele says. "It's difficult to have an optical stack without optical losses."

Arsenault predicts that Opalux will have the first products on the market within two years, probably in the form of advertising displays. But, he says, it will be a long while before P-Ink will be in a position to completely replace traditional displays. "The caveat is that we are not at video speeds," Arsenault says.

Currently, the P-Ink system can switch pixels in less than a second, which is on par with other e-paper displays. "We're still early in our development, and there's a lot of room for [improving] the material and optimizing its performance," says Arsenault.
Source:http://www.technologyreview.com

A Better Way to Make Hydrogen?

2007-09-06T04:17:00.000-07:00

A Purdue researcher claims aluminum alloys could make fuel-cell vehicles practical.

By Kevin Bullis

Gassing up: This aluminum alloy quickly pulls oxygen from water, in the process forming aluminum oxide and releasing hydrogen gas. The hydrogen could be used in place of gasoline in cars.
Credit: Jerry Woodall, Purdue University

A new process for using aluminum alloys to generate hydrogen from water could make fuel-cell vehicles more practical, says Jerry Woodall, a professor of electrical and computer engineering at Purdue.

Hydrogen fuel cells are attractive because they produce no harmful emissions, but hydrogen gas is hard to transport, and hydrogen vehicles have a limited range because it's difficult to store large amounts of hydrogen onboard. Many researchers are developing methods for storing more hydrogen, including packing it into carbon nanotubes or temporarily storing it in chemical compounds. Woodall's solution is to store hydrogen as water, splitting hydrogen from oxygen only when it's needed to power the vehicle.

Earlier this year, Woodall reported successfully generating significant amounts of hydrogen using a combination of aluminum and gallium. In those experiments, however, the alloy contained mostly gallium, which both limited the hydrogen-generating capacity of the material and kept costs high. At a nanotechnology conference on Friday, Woodall will present new work that shows that the process succeeds with an alloy containing 80 percent aluminum. This could make the system far more practical by reducing the amount of expensive gallium while increasing the amount of active material.

Woodall's process works because of aluminum's strong affinity for oxygen, which causes the metal to break water apart, forming aluminum oxide and releasing hydrogen. This basic chemical process is, of course, well known, but the problem has been that as soon as aluminum is exposed to air, it quickly forms a thin layer of aluminum oxide that seals off the bulk of the aluminum and prevents it from reacting with water. Woodall's insight, says Sunita Satyapal, who heads the Department of Energy's (DOE) hydrogen-storage program, is to use gallium to prevent this layer from completely sealing off the aluminum. Although the molecular mechanisms are still not understood, it's known that the gallium causes gaps in the oxide layer that allow the aluminum to react quickly with the oxygen in water, but not with the oxygen in air.

Woodall envisions a system in which aluminum pellets would be delivered to fueling stations where drivers would load about 50 kilograms of pellets and 20 kilograms of water into separate containers, with the two mixed as needed to generate hydrogen and aluminum oxide. (This would provide the equivalent of about 60 kilograms of gasoline, Woodall says.) The aluminum oxide can be recycled employing the same process used for aluminum cans, and the gallium can be easily separated from the aluminum oxide and used again.

But the electricity needed to recycle the aluminum could be a problem, since it would be a major source of pollution unless it comes from clean sources such as solar or wind. Also, Satyapal says that the energy efficiency of the process falls short of DOE goals.

The DOE, together with oil and car companies, has set goals for the amount of hydrogen that should be stored onboard a vehicle, aiming to provide the same range as gasoline-powered cars without changing vehicle designs or reducing cargo and passenger space. Woodall says that he can meet the goals for cars and other light vehicles, in part by recycling water produced by the fuel cells. The DOE, however, estimates that Woodall's process would take up too much room because, among other reasons, recycling water will likely not be practical, Satyapal says.

Woodall is working with AlGalCo, a startup based in West Lafayette, IN, to commercialize the process. The company's initial products will be fuel-cell generators that run on hydrogen produced with a version of his aluminum alloy.

Source: http://www.technologyreview.com

A New Type of Molecular Switch

2007-09-06T04:13:00.000-07:00

IBM researchers report a potential breakthrough in molecular electronics.

By Duncan Graham-Rowe

Molecular switch: The tip of a scanning tunneling microscope (shown in silver) probes a cross-shaped molecular switch to turn on and off a neighboring molecule. By inducing voltages, the probe causes two hydrogen atoms within the naphthalocyanine molecule to flip from one orientation to another.
Credit: IBM Zurich Research Labs

IBM scientists have created a novel molecular switch that is able to turn on and off without altering its shape. While such a switch is still years from being used in working devices, the scientists suggest that it does show a potential way to link together such molecular switches to form molecular logic gates for future computers.

Researchers during the past decade have been working to use individual molecules as electronic switches in the hope that they will eventually help make electronic devices even smaller and more powerful. (See "Molecular Computing.") But so far, such efforts have involved molecular processes that in some way deform the geometric shape of the molecule, says Peter Liljeroth, a researcher at IBM Zurich Research Laboratory, in Switzerland.

The problem is that changing the molecule's shape makes it difficult to link them together as switches. If a researcher wants to make something more complicated than just a molecular switch, such as a logic gate, then he or she has to be able to couple them together, says Liljeroth. "Having a single molecular switch is not really going to be useful for anything."

Liljeroth and his colleagues exploit atomic changes that take place at the center of a molecular cage, which does not alter the molecule's overall structure. In the latest issue of the journal Science, the group shows how its molecule can be electrically switched on and off. The researchers also demonstrate how three of these molecules can be made to work together when placed next to one another. "Injecting a current in one molecule will switch the state of another," says Liljeroth.

"The report constitutes an outstanding and remarkable piece of fundamental science," says Fraser Stoddart, director of the California Nanosystems Institute at the University of California, Los Angeles, who also works on molecular switching.

The IBM molecule is a naphthalocyanine, a class of compounds used in paints and organic optical electronics because of their intense bluish-purple color. The structure of IBM's molecule forms a cross shape that contains two opposing hydrogen atoms on either side of a central square void.

When the researchers placed the molecule on an ultrathin substrate, these opposing hydrogen atoms were found to flip from the sides of this quadrant to the top and bottom, or vice versa, when a sufficient voltage was applied. Yet regardless of which of these two states it's in, the geometry of the molecule remains constant.

When a lower voltage is applied, it's possible to read the state of the switch by measuring the current flowing through it. "A low voltage does not switch it, so we can read the state of the molecule," says Liljeroth.

"It's beautiful science," says Mark Reed, a physicist at Yale University, in New Haven, CT, who studies molecular devices. "The fact that they have this reversible change of the structure is very nice."

IBM's discovery was made by accident. "What we were actually investigating was the molecular vibration caused by adding electrons to the molecule," says Liljeroth. But in doing so, the researchers noticed this flipping of hydrogen atoms, a molecular reaction known as tautomerization.

To switch the molecule, the group used a scanning tunneling microscope (STM) operating at extremely low temperatures and in a vacuum. However, the reaction is driven electrically, albeit at picoamps, so the STM is not necessary for this reaction to take place, says Liljeroth. But the low temperature could be a major obstacle to making the process practical.

For this particular molecule, the temperature had to be maintained at just five degrees kelvin in order for the reaction to occur in a controlled way. "The reaction still occurs at room temperature," says Liljeroth. "But at room temperature, it would happen spontaneously." Nevertheless, he says, the potential is there to find new molecules that exhibit this behavior at higher temperatures in the hope of eventually building logic devices.

Demonstrating that one molecular switch can be turned on and off by applying a current to a neighboring molecule is a first step toward such logic. "The ability to apply a voltage to one molecule and cause tautomerization of a neighboring one has interesting implications for logic devices," says Stoddart. But, he says, the temperature constraint remains a huge challenge.

Stoddart also rejects the IBM group's dismissal of molecular switches that change shape; he argues that such molecules are at a much more advanced stage and can operate at room temperature. "I find it galling that scientists in the field of molecular electronics continue to be unfairly dismissive of research by others that is much more technologically advanced than their own, and yet also has a very sound theoretical and experimental basis to it."

Yale's Reed is also skeptical about the practical implications of the IBM finding. Any talk of turning this reaction into a device amounts to "excessive hyperbole" at this stage, he says. "It's like saying we have discovered silicon semiconductors, therefore we can make a Pentium."
Source: http://www.technologyreview.com

Craig Venter's Genome

2007-09-06T04:11:00.000-07:00

The genomic pioneer bares his genetic code to the world.

By Emily Singer

Personal genomes: Genomics pioneer Craig Venter (above) has sequenced his entire genome and released it to the world.

Credit: J. Craig Venter Institute

Five years ago, Craig Venter let out a big secret. As president of Celera Genomics, Venter had led the race between his company and a government-funded project to decode the human genome. After leaving Celera in 2002, Venter announced that much of the genome that had been sequenced there was his own. Now Venter and colleagues at the J. Craig Venter Institute have finished the job, filling in the gaps from the initial sequence to publish the first personal genome.

His newly released genome, published today in the journal PLoS Biology, differs from both of the previous versions of the human genome (one from Celera, the other from the Human Genome Project) in that it details all of the DNA inherited from both mother and father. Known as a diploid genome, this allows scientists to better estimate the variability in the genetic code. (In a genome sequence generated from a conglomerate of different individuals, some variations are lost in the averaging.) Within the genome of 2.810 billion base pairs, scientists found 4.1 million variations among the chromosomes; 1.2 million of these were previously unknown. Of the variations, 3.2 million were single nucleotide polymorphisms, or SNPs, the most well-characterized type of variation, while nearly one million were other kinds of variants, including insertions, deletions, and duplications.

Venter's genome will join that of another genomic pioneer, James Watson, codiscoverer of the structure of DNA. (See "The $2 Million Genome.") Announced in June, Watson's genome was sequenced by 454, a company based in Branford, CT, that's developing next-generation sequencing technologies. (For more on 454's technology, see "Sequencing in a Flash.")

Venter's and Watson's genomes are likely just the first in an upcoming wave of personal genomes, a crucial step in the advent of personalized medicine: the ability to tailor medical treatments to an individual's genetic profile. (See "The X Prize's New Frontier: Genomics.") Venter has already explored some of his genome, discovering that he carries genetic variations that put him at increased risk for Alzheimer's disease, heart disease, and macular degeneration. He says that he's been religiously taking statins, cholesterol-lowering drugs, ever since.

Venter talks with Technology Review about what lies ahead for his genome.

Technology Review: Why did you decide to embark on this project?

Craig Venter: The genome we published at Celera was a composite of five people. To put it together, it became clear that we had to make some informatics compromises--we had to leave out some of the genetic variation. We knew the only way to truly understand the genome would be to have the genome of one individual. Rather than starting from scratch, we decided to take what we had from the Celera genome and add more sequence. The goal was to get an accurate reference sequence from a single individual.

TR: How does your genome sequence add to what we know from the Human Genome Project?

CV: The government labs sequenced and assembled a composite haploid genome from several individuals [meaning it included a DNA sequence from only one of each chromosome pair]. There was the assumption back then that having half of the genome was all that was needed to understand human complexity. But it's become clear that we need to see the composite of the sets of chromosomes from both the mother and father to see the variation in the genome.

This genome has all the insertions and deletions and copy-number differences. That gives us a very different view.

TR: What's the most exciting finding so far?

CV: For me, the most exciting finding is that human-to-human variation is substantially higher than was anticipated from versions of the human genome done in 2001. If fact, it might be as much as tenfold higher: rather than being 99.9 percent identical, it's more like 99 percent identical. It's comforting to know we are not near-identical clones, as many people thought seven years ago.

TR: How will scientists use your genome sequence?

CV: It will serve as a reference genome. This is probably the first and last time anyone will spend the time, money, and energy to sequence a diploid genome using highly accurate Sanger sequencing. Future genomes, like those from 454 or George Church's Personal Genome Project, will be layered onto [existing] data, adding to the completeness of this genome. (See "The Personal Genome Project.") [The traditional Sanger sequencing method, used for the Human Genome Project and to generate Venter's sequence, generates longer pieces of DNA than do newer methods, such as that used by 454, making it easier to assemble the overlapping pieces.]

TR: James Watson released a version of his own genome earlier this summer. How is yours different?

CV: There has been nothing published yet on his genome, so we have no idea. But as I understand it, in contrast to really assembling a genome, they sequenced short fragments that are layered onto the sequence assembled at the NIH. So there are a lot of technical differences, but until it's published, we won't really know.

TR: You've had sections of your genome in the public domain for several years now. Any second thoughts about putting the entire high-quality sequence out there?

CV: No. And I applaud Watson for doing this as well. A key part of the message here is that people should not be afraid of their genetic codes or afraid to have other people see them. That's in contrast to the notion that this is dangerous information that should be kept under lock and key. We're not just our genetic code. There is very little from the code that will be 100 percent interpretable or applied.

TR: Have you searched your genome for disease-related mutations?

CV: Yes. I have a book coming out in October called A Life Decoded where I look at many variants and try to put them in context of my life. For example, I have a high statistical probability of having blue eyes, but you can't be 100 percent sure from my genome that I have them. The message is that everything in our genomes will be a statistical uncertainty. We're really just in the first stages of learning that.

Previous published genomes don't represent anyone, so we can't interpret human biology based on these. But now we can start to make human-genome inferences. We'll need tens of thousands to millions of genomes to put together a database that would allow interpretation of multiple rare variants and what they mean. That will take decades.

TR: How much did the project cost?

CV: The goal was not to see how cheaply we could sequence a genome; it was to see how accurately we could do it. It was clearly a multimillion-dollar project over the years.

Source: http://www.technologyreview.com

Mapping Wildfires

2007-09-01T10:14:00.000-07:00

NASA is using a new thermal-imaging sensor to track the fires in Santa Barbara.
By Brittany Sauser

Fire map: NASA engineers have developed a new thermal-imaging sensor that can accurately map a wildfire's behavior and pinpoint hot spots. The picture above is a composite of various images taken of a fire near Zaca Lake in Santa Barbara County, CA, on August 16, 2007. The researchers used Google Earth to visualize the data. The bright areas represent the fire’s hot spots.
Credit: NASA

At the onset of a wildfire, the United States Forest Service must deploy its resources as quickly and efficiently as possible to contain and stop the fire. Part of this process involves flying manned missions over the fire to map its location, hotspots, and the direction in which it's spreading. Now a new thermal-imaging sensor developed by NASA Ames Research Center (ARC) is making it easier for researchers to get an accurate picture of the ongoing fires in Santa Barbara. The system is still in development, but the researchers say that it could ultimately save resources, property, and lives.
The U.S. Forest Service and NASA are in the midst of testing the new technology on a remotely piloted unmanned aerial vehicle (UAV) flying over wildfires in California. The flight missions began on August 16, capturing images of a fire near Zaca Lake in Santa Barbara County, and they will continue once a week through September. The purpose of the missions is not only to test the sensor, but also to demonstrate the benefits of UAVs in wildfire tracking, their ability to handle and process data, and their ability to communicate this in real time, via satellite, to receiving stations on the ground.
The key to fighting wildfires is accurately knowing the positional information of a fire--not just taking an image of the fire, but understanding where the fire is and how it's behaving. "If you have one pixel [in an image] that shows there is a thermal heat source there, you need to know the latitude and longitude of that pixel," says Everett Hinkley, the National Remote Sensing Program manager at the U.S. Forest Service and coprincipal investigator on the project. To do so, the researchers use a scanner with a highly sensitive thermal mapping sensor designed by NASA.
The forest service's current system is similar but much less sophisticated: it only measures two portions of the light spectrum. The lack of data on other parts of the spectrum hinders the system's ability to precisely distinguish temperature gradients. The image files captured by the sensor must then be put on a "thumb drive" and dropped out of the aircraft through a tube as it flies near the command station, or the aircraft must land so that the data can be given to a colleague who performs the analysis.
The new equipment includes a 12-channel spectral sensor that runs from the visible spectrum into the reflected infrared and mid-infrared spectrum. Two of these channels were built specifically for the thermal portion of the spectrum and were highly calibrated to be able to distinguish hot spots. This is what makes it an effective wildfire imaging sensor, says Vince Ambrosia, an engineer at NASA ARC and the principal investigator of the fire missions.
The collection of images taken by the scanner is then processed onboard the aircraft in real time, and the data is automatically sent via satellite to a ground station, where it is incorporated into a geographic information system or map package. For the current fire missions, researchers are using Google Earth as their visualization tool. The data is displayed as an array of colors based on their intensity. The temperature ranges might be displayed as red, green, and blue, for example, with the hottest objects colored red. The system's ability to continuously send images of the fire allows researchers to better predict its next move. This helps fire fighters determine where to deploy resources.
The entire sensor package weighs less than 300 pounds and fits under the wing of an unmanned aircraft called Ikhana. Built by General Atomics Aeronautical Systems, Ikhana was acquired by NASA's Dryden Flight Research Center in November 2006. The Santa Barbara mission was the first for the fire-mapping system, but already the researchers are pushing its limits by demonstrating how the unmanned vehicle can collect data continuously for up to 24 hours. NASA hopes to continue using the system for earth-science and atmospheric-science data-collection missions.
"We are trying to augment current capabilities with unmanned aircraft and put them in situations where we wouldn't normally put a manned aircraft, such as dangerous circumstances or night flights at low altitude," says Hinkley. But he says that it will easily be 8 to 10 years before large UAVs, such as Ikhana, will be able to fly over fires on a regular basis, partly because of cost and man power. Currently the Federal Aviation Administration (FAA) requires that a pilot guide the plane from the ground, even though the plane could be programmed to fly on its own. In addition, the FAA hasn't established rules and regulations as to how such planes would fit in the national airspace.
Small, unmanned, aerial vehicles could very soon be used at local incidents, but the sensor technology has to be scaled down to be used on these planes, says Ambrosia.
For the foreseeable future, the U.S. Forest Service will continue to use manned aircraft. Once testing of the new thermal-imaging technology is complete, which is expected within a year, the U.S. Forest Service plans to put the system on its manned aircraft.

A Better Gauge on Battery Life

2007-09-01T10:11:00.000-07:00

A new battery-gauge chip could make mobile phones more reliable and help them last longer on a single charge.
By Kevin Bullis

Credit: Istockphoto.com

Texas Instruments (TI), based in Dallas, has developed a battery-gauge chip that can tell mobile-phone users down to the minute how much talking or standby time they have left--a degree of accuracy much greater than that provided by existing battery gauges. Such a precise gauge could allow smart-phone developers to squeeze more energy out of the battery, potentially increasing by half or more the amount of time that it lasts between charges.
The new TI gauge is more accurate than today's gauges, which measure a battery's voltage, because it measures a number of electrical properties. Voltage-only-based gauges are erratic and unreliable because voltage doesn't fall steadily as the battery is discharged. What's more, the voltage changes as the battery ages and experiences different temperatures. It also varies with different power demands on the battery.
The TI gauge is more accurate--to within 1 percent of the actual energy left in the battery--because it measures electrical properties besides voltage. Most important, it measures a feature of battery cells that is at the root of the voltage changes that make today's gauges unreliable. This feature, called impedance, is a measure of the opposition to current flow, and it changes with temperature, battery age, and the power demands on a battery.
Knowing the changes in impedance allows the chip to reinterpret voltage changes, keeping it from being fooled by voltage changes caused by these factors. For example, when a person makes a call, the voltage drops as soon as the phone transmits the signal. A conventional gauge would interpret this as a sudden drop in the amount of energy left in the battery, which could engage battery-saving measures in power-management software. The new gauge would recognize that the cell still has plenty of energy. The approach also works with low voltages caused by cell age.
The new gauge chip, which is incorporated either into the circuit boards of a phone or directly into a battery pack, could be particularly useful in smart phones. Some phone users have to assume that after the gauge has reached the halfway point, the battery could die at any moment. What's more, poor battery gauges make it difficult to employ power-management software on phones that could extend battery capacity. Power-management software slows down processors, turns off the camera's flash, and dims the screen to save the battery once it's low. It may also save data and shut down applications just before the battery dies. Such software, however, may engage power-saving measures too soon if it relies on an inaccurate battery gauge, resulting in sluggish device performance while there is still plenty of charge.
The problem gets worse as the battery ages and, as the battery is depleted, voltage drops more quickly. With conventional gauges, this could trigger the phone to shut down when there is still quite a bit of energy left. Indeed, much of the perceived loss in battery life in older phones is actually just a problem with the battery gauge. "You can lose 30 percent of the energy in a battery simply because the device shuts itself down too early," says Richard DelRossi, an engineer at TI. He says that the new, more accurate battery gauge could increase the usable battery capacity by as much as 50 to 100 percent, depending on the power-management strategy.
Other phone and chip makers are also developing better battery gauges. Approaches taken by Motorola, based in Schaumburg, IL, and PowerPrecise, a chip maker based in Herndon, VA, that's funded by Intel, combine voltage data with current measurements to determine how much energy has been used. Subtracting the amount of energy used can give a good idea of how much is left, as long as it's known how much energy was there to start with. But the capacity of the battery, as with the voltage, depends on certain conditions, such as temperature, battery age, and power demand. To adjust for these factors, these systems can refer to models of battery behavior based on earlier tests to guess how these conditions will affect the battery's overall capacity. Such a system gives a much more accurate gauge of battery charge than do voltage measurements alone, says Jerry Hallmark, who heads Motorola's research on energy consumption in mobile devices.

Source: http://www.technologyreview.com

Advanced Hurricane Forecasting

2007-09-01T10:07:00.000-07:00

With the 2007 hurricane season under way, scientists believe their new forecasting model will make more-accurate predictions, thereby saving lives.
By Brittany Sauser
Forecasting destruction: An image of Hurricane Katrina nearing peak strength was taken on August 28, 2005, by NASA satellites (top). The new hurricane-forecasting model, HWRF, reproduced the life cycle of Hurricane Katrina and was able to more accurately predict its intensity (bottom image).
Credit: NASA (top); NOAA/National Weather Service Environmental Modeling Center (bottom).

Forecasters are predicting yet another very active hurricane season for 2007, but this year meteorologists expect to be able to more accurately predict the path, structure, and intensity of storms. The device that will make this happen is a new hurricane-forecasting model developed by scientists at the National Oceanic and Atmospheric Administration (NOAA) Environmental Modeling Center. It will utilize advanced physics and data collected from environmental-observation equipment to outperform current models and provide scientists with real-time three-dimensional analysis of storm conditions.
The model is able to see the inner core of the hurricane, where the eye wall is located, better and in higher resolution than all other models, says T. N. Krishnamurti, a professor of meteorology at Florida State University. The eye wall is the region around the hurricane eye where the strongest winds and heaviest rains are located, thus the place of the highest storm intensity. "It is a very comprehensive model that is a significant development for hurricane forecasting," says Krishnamurti.
Currently, experts at the National Hurricane Center and the National Weather Service rely mostly on the Geophysical Fluid Dynamics Laboratory (GFDL) model. The model, which has been in use since 1995, forecasts the path and intensity of storms. Until now, it was the only global model that provided specific intensity forecasts of hurricanes. And while it is a very good model, it's limited by the amount of data it's based on. "It has a very crude representation of storms," says Naomi Surgi, the project leader for the new model and a scientist in the Environment Modeling Center. "GFDL is unable to use observations from satellites and aircraft in its analysis of the storm."
Isaac Ginis, a professor of oceanography at the University of Rhode Island (URI) who helped develop the GFDL model, agrees that the old model "has too many limitations" and, while it's able to forecast the path of a storm well, it is not as skillful at forecasting the intensity or power of a storm. Ginis is now a principal investigator for the new model, called the Hurricane Weather Research and Forecast (HWRF) model, which is able to gather a more varied and better set of observations and assimilate that data to produce a more accurate forecast.
This new model will use data collected from satellites, marine data buoys, and hurricane hunter aircraft, which fly directly into a hurricane's inner core and the surrounding atmosphere. The aircraft will be equipped with Doppler radars, which provide three-dimensional descriptions of the storm, most importantly observing the direction of hurricane winds. The aircraft will also be dropping ocean probes to better determine the location of the loop current, a warm ocean current in the Gulf of Mexico made up of little hot spots, known as warm core eddies, that give hurricanes moving over them a "real punch," says Surgi.
The hurricane model will then assimilate the data--wind conditions, temperature, pressure, humidity, and other oceanic and atmospheric factors in and around the storm--and analyze it using mathematics and physics to create a model, explains Surgi. To understand hurricane problems in the tropics, it is imperative to understand the physics of the air-sea interface. "In the last several years, we have learned a lot about the transfer of energy between the upper part of the ocean and the lowest layers of the atmosphere," she says. "And the energy fluxes across that boundary are tremendously important in terms of being able to forecast a hurricane's structure."
Improving the intensity forecast of a storm and being able to precisely analyze a hurricane's structure were scientists' main goals in developing the new model. It can now forecast these aspects from 24 hours out up to five days out with extreme accuracy, says Ginis. The new model was put to the test by running three full hurricane seasons--2004, 2005, and 2006--for storms in both the Atlantic and east Pacific basin, totaling close to 1,800 tests runs. For example, the model was able to reproduce the life cycle of Hurricane Katrina very well, accurately forecasting that it would become a category 5 hurricane over the Gulf of Mexico--something the old model was unable to predict.
Over the next several years, scientists at NOAA will continue to improve upon these initial advancements with further use of ocean observations. They plan to couple the HWRF with a wave model, which will allow scientists to better forecast storm surge, inland flooding, and rainfall. NOAA has, in addition to partnering with URI in 2006, started collaborating with researchers at the University of Southern Alabama to work on coupling the HWRF with a wave model and enhancing its forecasting features.
"This model is enormously important for emergency response and emergency managers, and also the public," says Ginis, "because we not only want to know where the storm is going to make landfall, but also how powerful it is going to be."

Making Colors with Magnets

2007-09-01T10:00:00.000-07:00

A new nanomaterial could lead to novel types of displays.
By Kevin Bullis
Rainbow rust: A solution of nanoscopic iron-oxide particles changes color as a magnet gets closer, causing the particles to rearrange. The color changes from red to blue as the magnetic field’s strength increases.
Credit: Yin laboratory, University of California, Riverside

A material developed by researchers at the University of California, Riverside can take on any color of the rainbow, simply by the scientists changing the distance between the material and a magnet. It could be used in sensors or, encapsulated in microcapsules, in rewritable posters or other large color displays.
The researchers made the material using a high-temperature method to synthesize nanoscale, crystalline particles of magnetite, a form of iron oxide. Each particle was made about 10 nanometers in diameter because, as they get much larger than this, magnetite particles become permanent magnets, and therefore would cluster together and fall out of solution. The 10-nanometer particles group together to form uniformly sized spherical clusters, each about 120 nanometers across; in tests, these clusters have stayed suspended in solution for months.
By coating these clusters with an electrically charged surfactant, the researchers cause the clusters to repel each other. When researchers use a magnet to counteract the repellent forces, the clusters rearrange and move closer together, changing the color of the light they reflect. The stronger the magnetic field, the closer the particles, with the color changing from the red end of the spectrum toward the blue, opposite end, as the magnet gets closer to the material. Moving the magnet away allows the electrostatic charge to force the particles apart again, returning the system to its original condition.
"The beauty of this system is that it is so simple," says Orlin Velev, a chemistry and biomolecular-engineering professor at North Carolina State University. "It can be used over large areas because it's very inexpensive and very easy to make." The work is published in the early online edition of the journal Angewandte Chemie.
A number of other researchers have developed color-changing materials, some of which are also controlled with magnetic forces; others use electrical or mechanical forces. The Riverside researchers, led by Yadong Yin, a professor of chemistry, however, are able to pack far more magnetic material per spherical building block that was previously possible. Sanford Asher, a professor of chemistry and materials science at the University of Pittsburgh who has encapsulated magnetite particles in polymer spheres, says that the new approach increases the amount of magnetic material by fivefold.
As a result, the new materials can be tuned to a larger number of colors than previously made materials. Indeed, North Carolina State's Velev, who works on materials that change color in response to electronic signals, says he knows of no other material capable of taking on such a wide range of colors.
The Riverside researchers found that processing the materials at high temperatures ensured that the 10-nanometer particles formed with a crystalline atomic structure. It also caused the particles to group together to form similarly sized clusters. In contrast, more commonly used room-temperature synthesis results in particles that form irregular agglomerations. The uniformity of the clusters and the crystallinity of the particles seem to improve the magnetic response of the materials, Yin says, although he and his colleagues are still looking into the underlying mechanisms involved.
The materials can switch colors at a rate of twice a second, which is still too slow for use in TVs and computer monitors. Yin hopes to increase switching speeds still more by using smaller amounts of material, perhaps in microscopic capsules. Such small amounts will make it easier to present a uniform magnetic field to the entire sample, potentially aiding the rearrangement of the clusters. Also, such microcapsules could be arranged to form pixels in a display, as is done now with E-Ink, a type of electronic paper used in some electronic book readers and a cell phones. (See "A Good Read.")
But even with faster speeds, Yin doesn't expect the materials to replace current computer-monitor technology. Rather, he has his sights set on larger-scale applications that would take advantage of the low cost of the materials. Examples could include posters that can be rewritten but don't have to change as fast as displays of video.
One significant drawback of the current materials is that they would need a constant power supply to preserve the magnetic field and hold the microcapsules at a set color. Yin's next step is to develop a version of the materials that remains stable after their color is changed--that is, until they're switched to a new color. If this is possible, then a poster could be printed with something like the read-write head on a hard drive, Yin says. It would preserve the image until it's rewritten with another pass of the print head, using no power in between.
"At this stage it's fun to play with," Velev says. "Maybe at later stages it could be used for some decorative purpose, such as paint that changes color, or some new types of labels or display boards. Right now it's a beautiful piece of research."

Source: http://www.technologyreview.com

Storing Light

2007-09-01T09:58:00.000-07:00

A new optical device could make high-speed computing and communications possible.
By Kevin Bullis

A microscopic device for storing light developed by researchers at Cornell University could help free up bottlenecks in optical communications and computing. This could potentially improve computer and communications speeds by an order of magnitude.
The new device relies on an optically controlled "gate" that can be opened and closed to trap and release light. Temporarily storing light pulses could make it possible to control the order in which bits of information are sent, as well as the timing, both of which are essential for routing communications via fiber optics. Today, such routing is done, for the most part, electronically, a slow and inefficient process that requires converting light pulses into electrons and back again. In computers, optical memory could also make possible optical communication between devices on computer chips.
Switching to optical routing has been a challenge because pulses of light, unlike electrons, are difficult to control. One way to slow down the pulses and control their movement would be to temporarily confine them to a small continuous loop. (See "Tiny Device Stores Light.") But the problem with this approach is getting the light in and out of such a trap, since any entry point will also serve as an exit that would allow light to escape. What's needed is a way to close the entryway once the light has entered, and to do so very quickly--in less time than it takes for the light to circle around the loop and escape. Later, when the light pulse is needed, the entryway could be opened again.
The Cornell researchers, led by Michal Lipson, a professor of electrical and computer engineering at the university, use a very fast, 1.5-picosecond pulse of light to open and close the entryway. The Cornell device includes two parallel silicon tracks, each 560 nanometers wide. Between these two tracks, and nearly touching them, are two silicon rings spaced a fraction of the width of a hair apart. To trap the light in these rings, the researchers turned to some of their earlier work, in which they found that the rings can be tuned to detour different colors by shining a brief pulse of light on them.
Light of a certain color passes along the silicon track, takes a detour through one of the rings, and then rejoins the silicon track and continues on its way. However, if the rings are retuned to the same frequency the moment after a light pulse enters a ring, the light pulse will circulate between the rings in a continuous loop rather than rejoin the silicon track and escape. Tuning the rings to different frequencies again, such as by shining another pulse on one of the rings, allows the light to escape this circuit and continue on to its destination.
Work remains to be done before such a device will function in a commercial system. So far, the rings only capture part of a pulse of light. As a result, any information encoded in the shape of the overall pulse is lost. This can be solved by compressing the pulse and using a cascade of rings, says Mehmet Yanik, a professor of electrical engineering and computer science at MIT.
The other issue is that the length of time a light pulse can be stored is relatively short, Lipson says. If the light stays in the ring for too long, it will be too weak to use. Lipson says it might be possible to make up for light losses by amplifying the light signal after it leaves the rings to restore any lost power.
Other schemes for storing light have been demonstrated in the past, but these were impractical, requiring carefully controlled conditions, for example, or a large, complicated system. The new approach is an important step forward because it makes it possible to store light in ambient conditions and in a very small device, says Marin Soljacic, a professor of physics at MIT. Once you've done that, he says, "then it becomes interesting to industry."

Nano Memory

2007-09-01T09:56:00.000-07:00

A nanowire device 100 times as dense as today's memory chips.
By Kevin Bullis

Two layers of 400 nanowires (blue and gray areas) encode data on molecules where they cross. Red lines are electrodes.
Credit: Jonathan E. Green and Habib Ahmad

Researchers at Caltech and the University of California, Los Angeles, have reached a new milestone in the effort to use individual molecules to store data, an approach that could dramatically shrink electronic circuitry. One hundred times as dense as today's memory chips, the Caltech device is the largest-ever array of memory bits made of molecular switches, with 160,000 bits in all. In the device, information is stored in molecules called rotaxanes, each of which has two components. One is barbell shaped; the other is a ring of atoms that moves between two stations on the bar when a voltage is applied. Two perpendicular layers of 400 nanowires deliver the voltage, reading or writing information. It's a big step forward from earlier prototype arrays of just a few thousand bits. "We thought that if we weren't able to make something at this scale, people would say that this is just an academic exercise," says James Heath, professor of chemistry at Caltech and one of the project's researchers. He cautions, however, that "there are problems still. We're not talking about technology that you would expect to come out tomorrow."

Tiny Device Stores Light

2007-09-01T07:37:00.000-07:00

IBM researchers have fabricated a silicon device that's a significant advance in making practical optical interconnects.

By Prachi Patel-Predd
An SEM image of an optical-delay line that has up to 100 microrings, all connected to a common silicon nanowire. The optical buffer can store up to 10 optical bits.
Credit: IBM

By forcing light to circle multiple times through ring-shaped structures carved into silicon, researchers at IBM have been able to delay the flow of light on a microchip. Being able to delay light is crucial for high-performance, ultrafast optical computers of the future that will process information using light and electrical signals.

It's easy to store electronic data in computer memory; light is harder to control. The new silicon device, described in this week's issue of Nature Photonics, is ten times smaller than those made in the past. It also works much better at high data speeds. "This work is approximately a factor of ten over the best achieved with [ring-shaped devices] so far," says Keren Bergman, an electrical-engineering professor at Columbia University.

Storing light on silicon is key for electronic-optical hybrid computers that researchers believe will be available a decade from now. In these computers, devices will compute using electrons but will move data to other devices and components using light--avoiding the use of copper wires or interconnects that tend to heat up at high computer frequencies.

But the optical interconnects would have to be laid out in an intelligent network, just as the copper wires on today's chips are. To transfer data packets efficiently between devices, the copper network on a chip has nodes where many interconnects converge. If a processor is sending data to a logic circuit, the data travels from node to node until it gets to the logic circuit. Each node in the network reads and processes the data packet to route it correctly to the next node. While the node makes a routing decision, it temporarily stores the data in electronic memory. To process and route data at the nodes of an optical-interconnect network, one would need to store, or delay, light so the node can make the routing decision.

Yurii Vlasov and his colleagues at IBM's T.J. Watson Research Center delay light on a silicon microchip by circulating it 60 to 70 times through ring-shaped structures, called resonators. The researchers make these resonators on a thin silicon layer mounted on an insulting silicon-oxide layer. They etch parallel trenches into the silicon that reach down to the oxide. The raised portion between the trenches acts like a silicon wire that shuttles light.

The researchers employ the same silicon wafers and techniques that are used to fabricate microprocessors at IBM. This makes it easy to "think of combining optical circuitry with electrical circuitry on the same chip," Vlasov says.

By connecting many rings, the researchers can build up the delay. With 56 rings connected to a common silicon wire, they get the longest delay: about half a nanosecond--which amounts to storing 10 optical bits--at a data speed of 20 gigabits per second.

Other researchers have made resonators on silicon before. But the smallest resonators so far have been about 100 micrometers wide, and cascading tens of them yields a device that is a few millimeters long--too big to be integrated into an electronic circuit. The IBM researchers make rings that are 12 micrometers in diameter, and they can fit up to 100 ring resonators into an area that is less than one-tenth of a square millimeter.

The size of the device is a major advance, Bergman says: "It is very close to the kinds of densities you would like to have on chip for optical interconnects." Achieving a delay of 10 bits at gigabits-per-second speeds, which would be typical of the data speed that optical interconnects of the future would be handling, is a breakthrough, she says. "This is a major step towards making optical interconnects a reality."

The device loses more light than would be acceptable in practical circuits, and Vlasov says that he and his team are working to reduce these losses. Once they do that, he says, they could put thousands of resonators together to store even more optical bits. For practical optical interconnects, you would need to store hundreds and thousands of bits.

It might take another 10 years before we see optical interconnects in computers, but the IBM research shows that the technology is viable, says Risto Puhakka, president of market-research firm VLSI Research, in Santa Clara, CA. "There are legs on this technology, and it could eventually be integrated with current circuits into chips."

Source: http://www.technologyreview.com

Microsoft's Plan to Map the World in Real Time

2007-09-01T07:34:00.000-07:00

Researchers are working on a system that allows sensors to track information and create up-to-date, searchable online maps.

By Kate Greene

Researchers at Microsoft are working on technology that they hope will someday enable people to browse online maps for up-to-the-minute information about local gas prices, traffic flows, restaurant wait times, and more. Eventually, says Suman Nath, a Microsoft researcher who works on the project, which is called SenseWeb, they would like to incorporate the technology into Windows Live Local (formerly Microsoft Virtual Earth), the company's online mapping platform.

By tracking real-life conditions, which are supplied directly by people or automated sensor equipment, and correlating that data with a searchable map, people could have a better idea of the activities going on in their local areas, says Nath, and make more informed decisions about, for instance, what driving route to take.

[For images from the SenseWeb application click here.]

"The value that you get out of [real-time data mapping] is huge," he says, and the applications can range from finding a parking spot in a cavernous parking garage to checking the traffic flow in different parts of a city.

Other research groups at the University of California at Berkeley, UCLA, Stanford, and MIT are working on similar projects for tracking environmental information. For instance, UCLA has a project in which sensors -- devices that measure physical quantities such as temperature, pressure, and sound -- are integrated with Google Earth, the company's downloadable mapping software. In addition, companies such as Agent Logic and Corda process real-time data and can correlate it with a location, mostly for businesses and governmental organizations.

Moreover, within the past year, Microsoft, Google, and Yahoo have been vying with each other to generate the most useful electronic maps (see "Killer Maps"). For the most part, though, the local information offered by Web-based mapping applications is updated only infrequently. And sites that offer real-time, local updates (about the status of public transportation, for instance), while useful, are designed for a single purpose.

What makes Microsoft's experimental project different from others that track information, Nath says, is that it would allow people to search for different types of real-time data within a user-specified area on a map, and progressively narrow that search. For instance, a person could highlight a region of a city and search for restaurants. SenseWeb would gather information provided by restaurants about their wait times and display it in various ways: the wait at specific establishments, the average wait for all restaurants in the region, or the minimum and maximum waits. If you needed to find a place to eat quickly, says Nath, but you learn that the minimum wait is 30 minutes in a certain part of town, you'd know to look in a different area. "You don't have to take the time to look at each individual restaurant," Nath says.

Additionally, a person could zoom into an area and see newly calculated information, such as maximum, minimum, and average wait times, according to the newly defined geography.

Searching for these types of real-time statistics within different areas on a map is a new take on displaying data on maps, says Phillip Levis, professor of computer science at Stanford University. "It's very different to give the average wait time in the city than it is to scan around the city and see each restaurant's wait time," he says.

SenseWeb is composed of three basic parts: sensors (or data-collecting units), Microsoft's database indexing scheme that sorts through the information, and the online map that lets users interact with the data. The sensors used in the project can vary in form and function, and can include thermometers, light sensors, cameras, and restaurant computers. SenseWeb puts baseline sensor information, such as location and function, into a database that's searchable by location and type of sensor information.

Then, if someone wants to check traffic conditions along a stretch of highway, for instance, the database will direct queries to cameras ("Web cams") located along the route -- and an image of traffic shows up on the map.

In order for people with sensors -- from researchers at universities to a private citizen with a Web cam -- to participate in SenseWeb, Nath says, they would have to be able to upload data to the Internet and provide information to the Microsoft group about their sensor, such as latitude, longitude, and the type of data it provides (for example, gas prices, temperature, or video).

One challenge for the SenseWeb project will be making the different types of information pulled into its database consistent enough to analyze and sort, says Samuel Madden, professor of computer science at MIT. For instance, there would need to be standard units for temperatures. "As soon as you start integrating all this data, you can imagine that weird things will happen," he says. "It's really a challenge to build tools that work with generic data and to come up with a way that anyone can publish their information."

Another, more fundamental hurdle for the SenseWeb project, Nath says, is getting people to register their sensors and sign on to the free program. Gas stations or restaurants may not even know about the project, or may not have an efficient way to pass along their data.

Therefore, in coming months, the Microsoft group will extend SenseWeb to universities that have already deployed sensors for other projects. In addition, the team is talking to a company that has sensors on parking spots, which, if integrated into Live Local, could help people find available parking more easily, he says.

For now, though, SenseWeb and Live Local are separate projects, according to Nath. The Live Local team "really loves this technology," he says, but right now "what's missing is the actual data."

Saving Power in Handhelds

2007-08-30T08:05:00.000-07:00

Taking advantage of human error tolerance could make cell phones more energy efficient.

By Larry Hardesty
Credit: Sándor Kelemen, Istockphoto.com

With the advent of the Apple iPhone and its big, clear screen, the idea of using the morning commute to catch up on missed episodes of Lost became a lot more attractive. But video chews through a handheld's battery much faster than, say, playing MP3s does. In the most recent issue of the Association for Computing Machinery's Transactions on Embedded Computing Systems, researchers at the University of Maryland describe a simple way for multimedia devices to save power. In simulations, the researchers applied their technique to several common digital-signal-processing chores and found that, on average, it would cut power consumption by about two-thirds.

The premise of the technique, says Gang Qu, one of its developers, is that in multimedia applications, "the end user can tolerate some execution failure." Much digital video, for example, plays at a rate of 30 frames per second. But "in the old movie theaters, they played at 24 frames per second," Qu says. "That's about 80 percent. If you can get 80 percent of the frames consistently correct, human beings will not be able to tell you've made mistakes."

Unlike the movies in the old theaters, a digital video isn't stored on reels of wound plastic; it's stored as a sequence of 1s and 0s. That sequence is decoded as the video plays, and the decoding time can vary from one frame to the next. So digital media systems are designed to work rapidly enough that even the hardest-to-decode frames will be ready to be displayed on time.

Qu thinks that's a waste of processing power. If the viewer won't miss the extra six frames of video per second, there's no reason to decode them. Lower decoding standards would mean less work for the video player's processor, and thus lower power consumption.

The straightforward way to ensure a decoding rate of 80 percent would be to decode, say, eight frames in a row and ignore the next two. That approach--which Qu calls the "naive approach"--did introduce power savings in the Maryland researchers' simulations. The problem is that such a system doesn't distinguish frames that are hard to decode from those that are easy: if frame five is the hardest, the decoder will still plow through it; if frame nine is the easiest, the decoder will still skip it.

Qu and his colleagues wrote an algorithm that imposes a series of time limits on the decoding process; if any of the limits is exceeded, the decoding is aborted. "You set certain milestones," Qu says, "and you say, 'Okay, after this time I still haven't reached that first milestone, so it seems this is a hard task. Let me drop this one.'" Using statistics on the durations of particular tasks, the researchers can tune the algorithm to guarantee any desired completion rate.

Raj Rajkumar, director of the Real-Time and Multimedia Systems Laboratory at Carnegie Mellon University, mentions that his colleague John Lehoczky and the University of Wisconsin's Parmesh Ramanathan have investigated approaches similar to Qu's. But he says that Qu's work is "the logical extension of earlier work. I think that what Gang did is very useful." Ramanathan adds that with Qu's approach, "my guess is that there will be considerable savings in power consumption. I think one can save quite a bit."

Indeed, the Maryland researchers' algorithm fared well in simulations, offering a 54 percent energy savings over the naive approach. "If you are using the current approach, which is going to keep on decoding everything," Qu says, "we are going to probably consume only slightly more than one-third of that energy. That means you can probably extend the battery life by three times."

Qu is quick to point out that the researchers' simulations involved signals similar, but not identical, to video signals; real video decoding might not produce such dramatic results. On the other hand, Qu says that more-recent video-coding standards call for frame rates higher than 30 frames per second. That means the decoding rate could drop below 80 percent, saving even more power.

And the tested algorithms do accurately model cell-phone voice decoding. In some handheld devices--notably the iPhone--voice communication is almost as big a battery drain as video playback. Without the handy reference of a near-century of analog movies, however, user tolerance for error in voice is harder to gauge.

Qu says his and his colleagues' power-saving scheme could be implemented in either hardware or software, although in the near term, software would certainly be the cheaper option. He adds that the work has drawn some corporate interest, but that there are no plans to commercialize it at the moment. Nonetheless, "if we got some partners," Qu says, "if they have a top engineer trying to work with us, this could be done in half a year."

Source: http://www.technologyreview.com

"Personalized" Embryonic Stem Cells for Sale

2007-08-30T08:02:00.002-07:00

A company offers to generate and store stem cells from leftover IVF embryos.

By Emily Singer
Stem-cell insurance: A company called StemLifeLine offers to generate embryonic stem cells (shown above) from leftover embryos created for in vitro fertilization. The cells could potentially be used for future medical treatments, although no embryonic-stem-cell-based treatments exist yet.
Credit: David Scharf, Science Photo Library

It's a new, rather dicey form of life insurance. A company in California called StemLifeLine has announced that it will offer a service to generate stem cells from excess frozen embryos stored after in vitro fertilization (IVF). The company promises a huge potential payoff: the cells could one day be used to treat disease in the buyers or in their families. But the service is already garnering criticism from some scientists and ethicists who say that without current medical uses for those cells, there's no point in people paying for them.

"I think the company's website overly hypes what may be possible," says Lawrence Goldstein, director of the stem-cell research program at the University of California, San Diego. "They are almost guaranteeing that therapies are around the corner, and now is the time to start banking stem cells, but that strikes me as premature for the field."

The new service is meant to take advantage of a growing interest in the field of regenerative medicine. Stem cells from adult blood or umbilical-cord blood are already used to treat some diseases, including sickle-cell anemia and several forms of leukemia. But these cells are largely limited to treating blood-related disorders and can't be grown in large numbers. Embryonic stem cells, on the other hand, can be coaxed to form virtually any type of cell in the body and can theoretically be replicated indefinitely. Scientists are developing ways to use them to replenish cells lost or damaged in ailments such as diabetes, Parkinson's disease, and heart disease. But as of now, those treatments are limited to the lab: no embryonic stem-cell-based therapies are approved for human use.

Couples who have had children via IVF are often left with extra embryos--and the rather difficult decision of what to do with them. As of 2003, an estimated 400,000 embryos remained in cryopreservation in the United States. Embryos can be donated to research or to other couples, destroyed, or left languishing in frozen storage. According to Ana Krtolica, StemLifeLine's CEO, the inspiration to form the company came from requests from clients at IVF clinics who were donating their embryos to research but wanted to know if they would have access to those cells if they were ever needed. (The answer is no.)

"We had a patient whose husband is a paraplegic," says Russell Foulk, a member of StemLifeLine's advisory board andmedical director of the Centers for Reproductive Medicine, a private clinic with offices in Nevada and Idaho. "They wanted to have a child and were excited about the possibility of creating neural cells from the extra embryos."

The technology to derive these cells is not new. Scientists at StemLifeLine use a similar procedure to that employed by research scientists for almost a decade, although the StemLifeLine scientists have refined it so that the resulting cells are fit for human use. For less than $10,000 (actual price depends on the collaborating IVF clinic), clients can send in their excess embryos and, in return, receive a line of stem cells that have been "quality assured," meaning they have been checked for the molecular markers that signify that the cells can be differentiated into multiple cell types. The company received certification as a tissue bank from the state of California last month, and it's in the process of generating cell lines for its first group of clients.

However, critics say that the service is premature. Extra embryos can remain in frozen storage for years. And in the case of the paraplegic man, no treatments using neural stem cells are yet available. "There is no reason to take your embryos out of cryopreservation and make a line of stem cells and then freeze them again until the technology is available to actually use them," says Eric Chiao, a stem-cell biologist at Stanford's Institute for Stem Cell Biology and Regenerative Medicine, in Palo Alto.

Chiao and others argue that by the time scientists have figured out how to use embryonic stem cells as therapies, they will likely have developed better ways of generating the stem cells themselves, possibly using cloning, in which scientists would generate perfectly matched stem cells from an adult cell of the patient to be treated. "My offspring would be better off if they used cloning to generate stem cells for themselves," says Arthur Caplan, an ethicist at the University of Pennsylvania. "In America, the best thing you can do is take the money you would have used and invest it in an insurance policy to maximize the likelihood that your kid will have health insurance someday."

Krtolica counters that because it takes two to three months to generate the cells, it's better to have them ready before an approved use in case a client needs them immediately.

Stem-cell scientists also say that StemLifeLine's description of its product as "personalized" stem cells is misleading. As with organ transplants, cell transplants require that the immune profile of the transplanted cells match the host as closely as possible. Scientists generally use the term personalized stem cells to refer to a type of stem cell not yet possible to create: those generated through cloning, making them a perfect genetic match to the donor. Cells made from discarded embryos would not be a perfect match to family members, says Doug Melton, codirector of the Harvard Stem Cell Institute, in Cambridge, MA. "This would be like having stem cells from a sibling, so immunosuppression is still an issue."

The prospect of generating stem-cell lines from embryos is likely to ignite new ethical arguments over embryonic stem cells. Critics of embryonic-stem-cell research oppose generating stem cells from embryos for any reason. But this service could spark growth of a practice that some find even more problematic: the creation of embryos solely as a source of cells. For example, some people might want to undergo IVF expressly for the stem cells, not to have a child. Krtolica says that she hasn't yet fielded any such requests but that ultimately, it would be up to the fertility clinics. Foulk, for one, says he would perform IVF under these circumstances.

Source: http://www.technologyreview.com

Intel's New Strategy: Power Efficiency

2007-08-30T08:02:00.001-07:00

Spurred by competitor AMD's rapid success, Intel is shifting its strategy toward more power-efficient microprocessors.

By Kate Greene

Amid increasing competition from Advanced Micro Devices (AMD), Intel is changing its chip-making philosophy: it's paying more attention to the power requirements of its microprocessors.

In July 2006, the chip-making giant will release a new microprocessor, called Core 2 Duo, designed for laptops and desktops. The new chip is based on Intel's current chip architecture, which replaced traditional single-core processing with two processing centers on a single chip. The company says that the Core 2 Duo will perform better than its current dual-core chip, and will be more energy-efficient, which could make laptop batteries last longer and desktop towers run cooler.

Paying attention to power consumption in microprocessors is a relatively new concept for the company, says Steve Pawlowski, a senior fellow at Intel, adding that the move may help Intel regain market share from its rival AMD. Historically, the most important metric in the industry has been processor performance -- the speed at which a processor can complete a task, such as calculating a spreadsheet. "We've always focused on performance at the expense of power [use]," Pawlowski says.

But basic changes have occurred in the PC market, which first led AMD, and now Intel, to rethink microprocessor designs. First, mobile devices have become the primary PC for many consumers -- who don't want a device that quickly drains a battery or gets too hot. Furthermore, as the size of transistors shrink, they're more likely to waste electricity through a physical process called "leakage," says Kevin McGrath, an AMD fellow -- and the more transistors on a chip, the more electricity is wasted.

AMD has been working on more-efficient microprocessors for several years, and now Intel is trying to level the playing field. Both Intel and AMD have tackled part of the problem by converting their chip line-ups to dual-core processors (see "Multicore Mania," December 2005), which turns out to be one way to increase efficiency. "Interestingly, going to multiple cores can be a very power-efficient way of computation," says Milo Martin, professor in the computer and information sciences department at the University of Pennsylvania.

Three aspects of multicore chips make them more efficient. First, when a chip has more than one core, the speed at which each core computes can be slowed down without impeding the speed of the entire chip. By slowing down the clock speed, explains Martin, engineers can decrease the computational rate of a single core by a factor of five, from one gigahertz to 200 megahertz, and the core consumes only one-30th of the power. Then, he says, even if five of those cores are assembled onto a single chip, only one-sixth of the power is consumed, yet the total computational rate of one gigahertz is maintained.

Second, smaller processor sizes reduce power consumption. The number of transistors each core has and the amount of silicon real-estate they take up determines the amount of power the core uses -- smaller processors have fewer transistors and thus use less power than larger processors. In a dual-core chip, the total number of transistors is greater than it is in a single-core chip, but each core has fewer transistors, making it more power efficient.

Third, some of the processor functions, such as controlling memory, can be shared between cores, so that each core consumes less energy by not performing a redundant task.

So transitioning to a multicore architecture is an obvious way to save power, and both Intel and AMD have done so. But they're looking at other ways to create efficiency. As Pawlowski explains, managing processors at the circuit and individual transistor level can also save power. For instance, specific circuits on a transistor are designated to control the manipulation of a photo or to play a DVD. When that circuit needs to be used, the transistors that comprise the circuit are turned on with a certain voltage. In a perfectly efficient chip, those transistors would turn on and off only when they're needed. However, even when a circuit is idle, its transistors are using a small voltage that slowly leaks out of the transistor, says Pawlowski. This leakage produces heat and wastes electricity.

While there is much overlap in the ways that AMD and Intel are approaching this problem of waste and leakage at the circuit level, their solutions are different. Intel is working to solve the problem by designating "sleep transistors" on a chip to micromanage the circuits in each core. These transistors completely turn off the voltage to transistors in circuits that are dormant.

AMD also puts portions of the processor to sleep, explains McGrath; but it does so by having an algorithm instruct the processor to go into various levels of sleep, by shutting down its clock speed so that standby computations aren't carried out as quickly. The algorithm "can ask a part to go into its lowest power state," he says, "there are five or six of these power states that are used depending on the load of the processor."

Intel has announced prices for its new energy-efficient chips -- they're less expensive than AMD's current offerings, which will put pressure on its rival. For Intel, though, the test of whether its power-saving chips can compete well against AMD's offerings won't come until its new processors hit the market.

Frozen Bacteria Repair Own DNA for Millennia

2007-08-30T07:57:00.000-07:00

Mason Inman
from National Geographic News

Bacteria can survive in deep freeze for hundreds of thousands of years by staying just alive enough to keep their DNA in good repair, a new study says.

In earlier work, researchers had found ancient bacteria in permafrost and in deep ice cores from Antarctica.

These bacteria, despite being trapped for millennia, were able to be revived and grown in the lab.

Some researchers had thought that bacteria would have to turn into dormant spores to survive for so long.

But if bacteria merely went dormant, metabolism would stop and various environmental factors would begin damaging their DNA.

Like an ancient scroll that's crumbling apart, the DNA becomes so damaged that it's indecipherable after about a hundred thousand years. Then the cells can't ever reproduce and the bacteria are effectively dead.

"Our results show that the best way to survive for a long time is to keep up metabolic activity," said Eske Willerslev, lead study author and a researcher at the University of Copenhagen in Denmark.

Doing this "allows for continuous DNA repair," Willerslev added.

The work suggests that if bacterial life existed on Mars or on Jupiter's moon Europa, it might still survive locked in icy soils.

The new study appears this week in the online advance edition of the Proceedings of the National Academy of Sciences.

Living, Just Barely

The new study examined DNA from bacteria found in permafrost from Siberia in Russia and Canada. The permafrost dated back to about a half-million years ago.

What the scientists found is that the bacteria appear to have kept up their metabolism.

These barely living bacteria did not seem to be reproducing, but they were still taking in nutrients and giving off carbon dioxide, like humans do when they breathe.

The bacteria were using some of these resources to keep their DNA in good shape, the study authors said.

But the researchers found that bacteria couldn't keep chugging along like this forever.

"You see a large diversity [of bacteria] in the modern samples, and as you get older and older, the diversity declines," Willerslev said.

The amount of carbon dioxide the bacteria gave off also dropped with age.

The limit for life in the permafrost is somewhere around 600,000 years old, the researchers say.

In older permafrost, the team couldn't detect any carbon dioxide emissions or any large pieces of DNA indicative of living bacteria.

By about 750,000 years old, the bacteria trapped in the permafrost seemed to be completely dead.

Soil vs. Ice

Some scientists have claimed to be able to revive far older bacteria preserved in amber or salts, but Willerslev has doubts about these results.

"I've been extremely skeptical about these previous results," Willerslev said.

But in the much colder environments of Mars or Europa, life might be able to survive while frozen for much longer, Willerslev said.

At those lower temperatures, DNA damage would accumulate more slowly.

So the new results "could suggest that if you had similar life on Mars, it could exist for much longer," he said.

Brent Christner of Louisiana State University welcomes the new results, which he finds convincing.

Christner and others have been studying ancient ice from deep in the Antarctic ice sheet and have found live bacteria there that have been frozen in place for perhaps one to two million years.

These ancient bacteria seemed to be repairing themselves, but the team didn't have direct evidence showing how the microbes were surviving so long.

"This study confirms and corroborates everything we've been finding with ancient glacial ice," Christner said.

Still, Willerslev is cautious about making this connection.

Glacial ice, he said, "is a completely different environment from permafrost, which is basically frozen soil" and contains lots of nutrients.

Supersonic "Hail" Seeds Star Systems With Water

2007-08-30T07:53:00.000-07:00

John Roach
from National Geographic News

Evidence of water vapor "raining down" on a newly forming star system is offering the first direct look at how water likely gets incorporated into planets, NASA researchers announced.

(Related: "First Proof of Wet 'Hot Jupiter' Outside Solar System" [July 11, 2007].)

The water—enough to fill Earth's oceans five times over—falls at supersonic speeds in the form of a hail-like substance from the envelope of dust and gas that gave birth to the star.

The hail vaporizes when it smacks into the dusty disk around the embryonic star where planets are thought to take shape, according to models that best explain the observed data.

"This is the first time we've ever seen the process by which the surrounding envelope's material arrives at the disk," said Dan Watson, an astrophysicist at the University of Rochester in New York.

Watson is lead author of a paper describing the discovery in tomorrow's issue of the journal Nature.

"Since the disk is what's eventually going to give rise to the planetary system around the star, what we are seeing is the process by which that disk formed and therefore the initial conditions of planetary formation."

Star Development

The new work is based on observations of an embryonic star system taken with NASA's Spitzer Space Telescope (see images of stellar nurseries captured by Spitzer).

Astronomers observe such protostar systems in the infrared spectrum, because visible light is easily absorbed by the systems' dusty environments, making them invisible to the naked eye.

Water vapor emits a distinctive spectrum in infrared light.

The protostar lies about a thousand light-years from Earth in a cloud gas and dust. The whole system is called NGC 1333-IRAS 4B, or IRAS 4B for short.

The star is a warm, dense blob of material at the core of the cloud. A disk of planet-forming material is believed to circle the blob.

The radius of the disk is just larger than the distance between Pluto and the sun: about 3.6 billion miles (5.8 billion kilometers).

Based on their data, Watson and his colleagues say that the surface of the disk is -153 degrees Fahrenheit (-103 degrees Celsius).

While this seems frigid by Earth standards, Watson explained, the properties of water are different at the atmospheric pressure of the protostar, which is about a billionth of the pressure at sea level on Earth.

In addition, material equal to 23 times the mass of Earth arrives at the disk each year, Watson said.

"That's the material that's heating on arrival and then gradually cooling as it joins the lower parts of the disk," he said.

"This is very wet stuff. The original state is very wet," he added. "There's plenty of water to make a solar system out of."

Right Angle

Of the 30 embryonic star systems observed with Spitzer, only IRAS 4B showed signs of water vapor.

According to Watson, this is most likely because the protostar's axis points almost directly at Earth.

"The other 29 could very well have just as much water emission as IRAS 4B, but they are turned the wrong way and you can't see them," he said.

The team has already identified hundreds more protostar systems like IRAS 4B and plans to observe them with the Spitzer telescope, including more stars that exhibit this rare orientation.

Higher Games

2007-08-29T08:33:00.001-07:00

It's been 10 years since IBM's Deep Blue beat Garry Kasparov in chess. A prominent philosopher asks what the match meant.

By Daniel C. Dennett

World chess champion Garry Kasparov during his sixth and final game against IBM’s Deep Blue in 1997. He lost in 19 moves.
Credit: Stan Honda/AFP/Getty Images

In the popular imagination, chess isn't like a spelling bee or Trivial Pursuit, a competition to see who can hold the most facts in memory and consult them quickly. In chess, as in the arts and sciences, there is plenty of room for beauty, subtlety, and deep originality. Chess requires brilliant thinking, supposedly the one feat that would be--forever--beyond the reach of any computer. But for a decade, human beings have had to live with the fact that one of our species' most celebrated intellectual summits--the title of world chess champion--has to be shared with a machine, Deep Blue, which beat Garry Kasparov in a highly publicized match in 1997. How could this be? What lessons could be gleaned from this shocking upset? Did we learn that machines could actually think as well as the smartest of us, or had chess been exposed as not such a deep game after all?

The following years saw two other human-machine chess matches that stand out: a hard-fought draw between Vladimir Kramnik and Deep Fritz in Bahrain in 2002 and a draw between Kasparov and Deep Junior in New York in 2003, in a series of games that the New York City Sports Commission called "the first World Chess Championship sanctioned by both the Fédération Internationale des Échecs (FIDE), the international governing body of chess, and the International Computer Game Association (ICGA)."

The verdict that computers are the equal of human beings in chess could hardly be more official, which makes the caviling all the more pathetic. The excuses sometimes take this form: "Yes, but machines don't play chess the way human beings play chess!" Or sometimes this: "What the machines do isn't really playing chess at all." Well, then, what would be really playing chess?

This is not a trivial question. The best computer chess is well nigh indistinguishable from the best human chess, except for one thing: computers don't know when to accept a draw. Computers--at least currently existing computers--can't be bored or embarrassed, or anxious about losing the respect of the other players, and these are aspects of life that human competitors always have to contend with, and sometimes even exploit, in their games. Offering or accepting a draw, or resigning, is the one decision that opens the hermetically sealed world of chess to the real world, in which life is short and there are things more important than chess to think about. This boundary crossing can be simulated with an arbitrary rule, or by allowing the computer's handlers to step in. Human players often try to intimidate or embarrass their human opponents, but this is like the covert pushing and shoving that goes on in soccer matches. The imperviousness of computers to this sort of gamesmanship means that if you beat them at all, you have to beat them fair and square--and isn't that just what Kasparov and Kramnik were unable to do?

Yes, but so what? Silicon machines can now play chess better than any protein machines can. Big deal. This calm and reasonable reaction, however, is hard for most people to sustain. They don't like the idea that their brains are protein machines. When Deep Blue beat Kasparov in 1997, many commentators were tempted to insist that its brute-force search methods were entirely unlike the exploratory processes that Kasparov used when he conjured up his chess moves. But that is simply not so. Kasparov's brain is made of organic materials and has an architecture notably unlike that of Deep Blue, but it is still, so far as we know, a massively parallel search engine that has an outstanding array of heuristic pruning techniques that keep it from wasting time on unlikely branches.

True, there's no doubt that investment in research and development has a different profile in the two cases; Kasparov has methods of extracting good design principles from past games, so that he can recognize, and decide to ignore, huge portions of the branching tree of possible game continuations that Deep Blue had to canvass seriatim. Kasparov's reliance on this "insight" meant that the shape of his search trees--all the nodes explicitly evaluated--no doubt differed dramatically from the shape of Deep Blue's, but this did not constitute an entirely different means of choosing a move. Whenever Deep Blue's exhaustive searches closed off a type of avenue that it had some means of recognizing, it could reuse that research whenever appropriate, just like Kasparov. Much of this analytical work had been done for Deep Blue by its designers, but Kasparov had likewise benefited from hundreds of thousands of person-years of chess exploration transmitted to him by players, coaches, and books.

It is interesting in this regard to contemplate the suggestion made by Bobby Fischer, who has proposed to restore the game of chess to its intended rational purity by requiring that the major pieces be randomly placed in the back row at the start of each game (randomly, but in mirror image for black and white, with a white-square bishop and a black-square bishop, and the king between the rooks). Fischer Random Chess would render the mountain of memorized openings almost entirely obsolete, for humans and machines alike, since they would come into play much less than 1 percent of the time. The chess player would be thrown back onto fundamental principles; one would have to do more of the hard design work in real time. It is far from clear whether this change in rules would benefit human beings or computers more. It depends on which type of chess player is relying most heavily on what is, in effect, rote memory.

The fact is that the search space for chess is too big for even Deep Blue to explore exhaustively in real time, so like Kasparov, it prunes its search trees by taking calculated risks, and like Kasparov, it often gets these risks precalculated. Both the man and the computer presumably do massive amounts of "brute force" computation on their very different architectures. After all, what do neurons know about chess? Any work they do must use brute force of one sort or another.

It may seem that I am begging the question by describing the work done by Kasparov's brain in this way, but the work has to be done somehow, and no way of getting it done other than this computational approach has ever been articulated. It won't do to say that Kasparov uses "insight" or "intuition," since that just means that Kasparov himself has no understanding of how the good results come to him. So since nobody knows how Kasparov's brain does it--least of all Kasparov himself--there is not yet any evidence at all that Kasparov's means are so very unlike the means exploited by Deep Blue.

People should remember this when they are tempted to insist that "of course" Kasparov plays chess in a way entirely different from how a computer plays the game. What on earth could provoke someone to go out on a limb like that? Wishful thinking? Fear?

In an editorial written at the time of the Deep Blue match, "Mind over Matter" (May 10, 1997), the New York Times opined:

The real significance of this over-hyped chess match is that it is forcing us to ponder just what, if anything, is uniquely human. We prefer to believe that something sets us apart from the machines we devise. Perhaps it is found in such concepts as creativity, intuition, consciousness, esthetic or moral judgment, courage or even the ability to be intimidated by Deep Blue.

The ability to be intimidated? Is that really one of our prized qualities? Yes, according to the Times:

Nobody knows enough about such characteristics to know if they are truly beyond machines in the very long run, but it is nice to think that they are.

Why is it nice to think this? Why isn't it just as nice--or nicer--to think that we human beings might succeed in designing and building brainchildren that are even more wonderful than our biologically begotten children? The match between Kasparov and Deep Blue didn't settle any great metaphysical issue, but it certainly exposed the weakness in some widespread opinions. Many people still cling, white-knuckled, to a brittle vision of our minds as mysterious immaterial souls, or--just as romantic--as the products of brains composed of wonder tissue engaged in irreducible noncomputational (perhaps alchemical?) processes. They often seem to think that if our brains were in fact just protein machines, we couldn't be responsible, lovable, valuable persons.

Finding that conclusion attractive doesn't show a deep understanding of responsibility, love, and value; it shows a shallow appreciation of the powers of machines with trillions of moving parts.

Daniel Dennett is the codirector of the Center for Cognitive Studies at Tufts University, where he is also a professor of philosophy.

Uninspiring Vista

2007-08-29T08:32:00.000-07:00

How Microsoft's long-awaited operating system disappointed a stubborn fan.

By Erika Jonietz

Vista's Aero visual environment includes the flip 3-D feature, which allows a user to cycle through a stack of open windows to find the desired application, shown above, and translucent window borders. Vista also offers "Gadgets," small programs that recall Mac "Widgets" (far right of screen above).

For most of the last two decades, I have been a Microsoft apologist. I mean, not merely a contented user of the company's operating systems and software, not just a fan, but a champion. I have insisted that MS-DOS wasn't hard to use (once you got used to it), that Windows 3.1 was the greatest innovation in desktop operating systems, that Word was in fact superior to WordPerfect, and that Windows XP was, quite simply, "it."

When I was forced to use Apple's Mac OS (versions 7.6 through 9.2) for a series of jobs, I grumbled, griped, and insisted that Windows was better. Even as I slowly acclimated at work, I bought only Windows PCs for myself and avoided my roommate's recherché new iBook as if it were fugu. I admitted it was pretty, but I just knew that you got more computing power for your buck from an Intel-based Windows machine, and of course there was far more software available for PCs. Yet my adoration wasn't entirely logical; I knew from experience, for example, that Mac crashes were easier to recover from than the infamous Blue Screen of Death. At the heart of it all, I was simply more used to Windows. Even when I finally bought a Mac three years ago, it was solely to meet the computing requirements of some of the publications I worked with. I turned it on only when I had to, sticking to my Windows computer for everyday tasks.

So you might think I would be predisposed to love Vista, Microsoft's newest version of Windows, which was scheduled to be released to consumers at the end of January. And indeed, I leaped at the opportunity to review it. I couldn't wait to finally see and use the long-delayed operating system that I had been reading and writing about for more than three years. Regardless of widespread skepticism, I was confident that Vista would dazzle me, and I looked forward to saying so in print.

Ironically, playing around with Vista for more than a month has done what years of experience and exhortations from Mac-loving friends could not: it has converted me into a Mac fan.

A little context and a caveat: in order to meet print deadlines, I had to review the "RC1" version of Vista Ultimate, which Microsoft released in order to gather feedback from over-eager early adopters. Such post-beta, prerelease testing reveals bugs and deficits that in-house testing misses; debuggers cannot mimic all the various configurations of hardware, software, and peripherals that users will assemble. And Vista RC1 was maddeningly buggy. Although I reminded myself repeatedly that most of the problems I encountered would be fixed in the final version, my opinions about Vista are probably colored by my frustrations.

Still, my very first impression of Vista was positive. Quite simply, it's beautiful. The Aero visual interface provides some cool effects, such as translucent window borders and a way to scroll through a 3-D "stack" of your open windows to find the one you want. Networking computers is virtually automatic, as it was supposed to be but never quite has been with Windows XP. The Photo Gallery is the best built-in organizer I've used to manage digital pictures; it even includes basic photo correction tools.

But many of Vista's "new" features seemed terribly familiar to me--as they will to any user of Apple's OS X Tiger operating system. Live thumbnails that display petite versions of minimized windows, search boxes integrated into every Explorer window, and especially the Sidebar--which contains "Gadgets" such as a weather updater and a headline reader--all mimic OS X features introduced in 2005. The Windows versions are outstanding--they're just not really innovative.

Unfortunately, Vista RC1 contained bugs that rendered some promising features, such as the new version of Windows Media Center, unusable for me (an acquaintance who acquired a final copy of Vista ahead of release assures me that all that has been fixed).

My efforts to get Media Center working highlighted two big problems with Vista. First, it's a memory hog. The hundreds of new features jammed into it have made it a prime example of software bloat, perhaps the quintessence of programmer Niklaus Wirth's law that software gets slower faster than hardware gets faster (for more on the problems with software design that lead to bloat, see "Anything You Can Do, I Can Do Meta"). Although my computer meets the minimum requirements of a "Vista Premium Ready PC," with one gigabyte of RAM, I could run only a few simple programs, such as a Web browser and word processor, without running out of memory. I couldn't even watch a movie: Windows Media Player could read the contents of the DVD, but there wasn't enough memory to actually play it. In short, you need a hell of a computer just to run this OS.

Second, users choosing to install the 64-bit version of Vista on computers they already own will have a hard time finding drivers, the software needed to control hardware subsystems and peripherals such as video cards, modems, or printers. Microsoft's Windows Vista Upgrade Advisor program, which I ran before installing Vista, assured me that my laptop was fully compatible with the 64-bit version. But once I installed it, my speakers would not work. It seems that none of the companies concerned had written a driver for my sound card; it took more than 10 hours of effort to find a workaround. Nor do drivers exist for my modem, printer, or several other things I rely on. For some of the newer components, like the modem, manufacturers will probably have released 64-bit drivers by the time this review appears. But companies have no incentive to write complicated new drivers for older peripherals like my printer. And because rules written into the 64-bit version of Vista limit the installation of some independently written drivers, users will be virtually forced to buy new peripherals if they want to run it.

Struggling to get my computer to do the most basic things reminded me forcefully of similar battles with previous versions of Windows--for instance, the time an MIT electrical engineer had to help me figure out how to get my computer to display anything on my monitor after I upgraded to Windows 98. Playing with OS X Tiger in order to make accurate comparisons for this review, I had a personal epiphany: Windows is complicated. Macs are simple.

This may seem extraordinarily obvious; after all, Apple has built an entire advertising campaign around the concept. But I am obstinate, and I have loved Windows for a long time. Now, however, simplicity is increasingly important to me. I just want things to work, and with my Mac, they do. Though my Mac barely exceeds the processor and memory requirements for OS X Tiger, every bundled program runs perfectly. The five-year-old printer that doesn't work at all with Vista performs beautifully with OS X, not because the manufacturer bothered to write a new Mac driver for my aging standby, but because Apple included a third-party, open-source driver designed to support older printers in Tiger. Instead of facing the planned obsolescence of my printer, I can stick with it as long as I like.

And my deepest-seated reasons for preferring Windows PCs--more computing power for the money and greater software availability--have evaporated in the last year. Apple's decision to use the same Intel chips found in Windows machines has changed everything. Users can now run OS X and Windows on the same computer; with third-party software such as Parallels Desktop, you don't even need to reboot to switch back and forth. The chip swap also makes it possible to compare prices directly. I recently used the Apple and Dell websites to price comparable desktops and laptops; they were $100 apart or less in each case. The difference is that Apple doesn't offer any lower-end processors, so its cheapest computers cost quite a bit more than the least-expensive PCs. As Vista penetrates the market, however, the slower processors are likely to become obsolete--minimizing any cost differences between PCs and Macs.

I may need Windows for a long time to come; many electronic gadgets such as PDAs and MP3 players can only be synched with a computer running Windows, and some software is still not available for Macs. But the long-predicted migration of software from the desktop to the Internet is finally happening. Organizations now routinely access crucial programs from commercial Web servers, and consumers use Google's services to compose, edit, and store their e-mail, calendars, and even documents and spreadsheets (see "Homo Conexus," July/August 2006). As this shift accelerates, finding software that works with a particular operating system will be less of a concern. People will be able to base decisions about which OS to use strictly on merit, and on personal preference. For me, if the choice is between struggling to configure every feature and being able to boot up and get to work, at long last I choose the Mac.

Erika Jonietz is a Technology Review senior editor.

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Electric Fields Kill Tumors

2007-08-29T08:30:00.000-07:00

A promising device uses electric fields to destroy cancer cells in the brain.

By Katherine Bourzac

Zapping tumors: Brain-cancer patients in a trial for a portable device that sends a weak electric field into the brain must wear electrodes almost constantly. One patient in a pilot clinical trial for the device, who still had cancer after radiation, chemotherapy, and surgery, experienced a complete recovery. The MRI at top shows a tumor on the left side of this patient’s brain before treatment. The MRI at bottom, taken after eight months of treatment, shows no tumor.
Credit: Yoram Palti, NovoCure (top image); Proceedings of the National Academy of Sciences (bottom MRIs)

An Israeli company is conducting human tests for a device that uses weak electric fields to kill cancer cells but has no effect on normal cells. The device is in late-stage clinical trials in the United States and Europe for glioblastoma, a deadly brain cancer. It is also being tested in Europe for its effectiveness against breast cancer. In the lab and in animal testing, treatment with electric fields has killed cancer cells of every type tested.

The electric-field therapy was developed by Yoram Palti, a physiologist at the Technion-Israel Institute of Technology, in Haifa, who founded the company NovoCure to commercialize the treatment. Palti's electric fields cause dividing cancer cells to explode while having no significant impact on normal tissues. The range of electric fields generated by the device harms only dividing cells. And since normal cells divide at a much slower rate than cancer cells, the electric fields target cancer cells. "An Achilles' heel of cancer cells is that they have to divide," says Herbert Engelhard, chief of neuro-oncology in the department of neurosurgery at the University of Illinois, Chicago.

Even after chemotherapy, radiation therapy, and surgery, about 85 to 90 percent of glioblastoma patients' cancer still progresses, and their survival rates are low, says Engelhard. He has about 10 glioblastoma patients enrolled in the trial, which is testing the unusual treatment in patients for whom all other approaches have failed. Engelhard says that the results are encouraging but that it's too early to comment on the treatment's efficacy.

The electric fields' different effects on normal and dividing cells mostly have to do with geometry. A dividing cell has what Palti calls "an hourglass shape rather than a round shape." The electric field generated by the NovoCure device passes around and through round cells in a uniform fashion. But the narrow neck that pinches in at the center of a dividing cell acts like a lens, concentrating the electric field at this point. This non-uniform electric field wreaks havoc on dividing cells. The electric field tears apart important biological molecules, such as DNA and the structural proteins that pull the chromosomes into place during cell division. Dividing cells simply "disintegrate," says Palti.

Palti, who for years has been studying the effect of electric fields on cancer and normal cells, says that he has verified this mechanism in computer models and experiments in the lab. "The physics are solid," says David Cohen, associate professor of radiology at Harvard Medical School.

Patients in the glioblastoma clinical trial wear the device almost constantly, carrying necessary components in a briefcase. A wire emerging from the briefcase connects to adhesive electrodes covering the skull. Alternating electric fields pass through the scalp, into the skull, and on to the brain. The Food and Drug Administration approved the device for late-stage clinical trials for glioblastoma following promising results from a pilot study in 10 patients, one of whom had a complete recovery.

One exciting result from his studies, says Palti, is that there is "excellent synergy between electric-field treatment and chemotherapy." In an unpublished lab study of several types of cancer, he says, adding electric-field treatment makes several chemotherapeutics more effective at lower doses. NovoCure is now conducting a pilot trial in Europe in which patients begin electric-field treatment in conjunction with chemotherapy when they are first diagnosed with glioblastoma. The results are preliminary, but, Palti says, "I strongly believe that the combination treatment will ... enable one to reduce the chemo doses to levels where their side effects will be significantly reduced."

Palti says that after more than 200 cumulative months of electric-field treatment in several patients, there have been no side effects beyond irritation of the scalp. "So far, toxicity seems to be low," says Engelhard. This stands in stark contrast to chemotherapy and radiation, which cause many side effects, including nausea, hair loss, and fatigue.

One worry is that the electric-field treatment could affect healthy cells that are dividing. The electric fields emerging from the electrodes can't be focused, says Cohen, and although they are primarily concentrated in the brain in the glioblastoma trial, they may also reach other parts of the body where cells are dividing. Cells in the bone marrow, for example, multiply at a great rate to create red blood cells and immune cells. But Palti says that the electric fields have no effect on blood-cell counts. The bone and muscle surrounding the marrow appear to protect the cells..

It's unclear how long patients will need to wear the device. "We're hesitant to stop treatment, because the consequences could be severe," says Palti, although one patient whose cancer has disappeared has stopped wearing the device. Patients must go to the clinic twice a week to have their heads shaved so that their hair doesn't interrupt contact between the scalp and the electrodes. The device itself costs only about $1,000 to manufacture, but replacing the electrodes twice a week is expensive.

Engelhard says that he got involved with the NovoCure clinical trial because the electric-field treatment is "radically different" from all existing cancer treatments. For patients with recurrent glioblastoma and other deadly forms of cancer, there are few options. "Researching and testing new therapies for this type of patient is very important," says Engelhard.

Nanowire LEDs

2007-08-29T08:29:00.000-07:00

Infrared light-emitting nanowires could lead to optical communications on microchips.

By Kevin Bullis

Microscopic LED: A thin indium-nitride nanowire spans two electrodes. When a current is applied, it emits infrared light.
Credit: IBM Research

Researchers at IBM Research in Yorktown Heights, NY, have demonstrated a new way to convert electricity into light in nanowire-based light-emitting devices (LEDs). The nanowire LEDs could eventually be used for telecommunications and for faster communications between devices on microchips. The approach could also pave the way for a new type of bright, efficient display.

The researchers built an LED resembling a transistor that consists of an indium-nitride nanowire stretched between two electrodes on top of a silicon substrate. The nanowire is about 100 nanometers wide and spans a distance of less than 10 micrometers. When the researchers apply a current to the nanowire, it emits light. While nanowires that emit light have been made before, the new devices rely on different physical mechanisms that are simpler; as a result, the nanowire LED could be more efficient and have improved performance. What's more, the device succeeds in emitting infrared light, which has been particularly difficult for nanowires to do, says Phaedon Avouris, one of the IBM researchers.

Typically, light in LEDs is produced by injecting both electrons and their positive counterparts, holes, into an active material, where they combine and emit light. With the new devices, the researchers only have to inject electrons; these cause electrons and holes to form locally, inside the nanowires. The mechanism could be more efficient because a single electron can be used to generate more than one electron-hole pair. What's more, the researchers have demonstrated that the nanowires can produce more intense light emission than other LEDs.

The nanowires' small size and compatibility with silicon make them attractive for integration on chips, says Eugene Fitzgerald, a professor of materials science and engineering at MIT. The nanowires also emit infrared light, which makes them ideal for fiber-optic telecommunications and for optical communications between devices on microchips that could help dramatically speed up computers.

The nanowire LEDs extend the range of colors that can be emitted from nitride-based materials, Fitzgerald says. Nitride materials are the basis of the blue lasers in high-definition DVD players, he says, and they have also been useful for emitting green light. If the nanowires can be tuned to emit red light, as seems likely, then red, green, and blue LEDs could all be created with variations of the same material, making it practical to manufacture them all on the same substrate. Eventually, it may be possible to arrange such LEDs into the pixels of full-color displays that are brighter, more efficient, and better looking than today's flat-panel LCD displays, Fitzgerald says.

Not only did the wires emit infrared light, but they also showed a peculiar ability to emit more intense light as temperatures rose; ordinarily, at high temperatures light emission dims or stops. This could lead to LEDs that can withstand high temperatures, a property that could be useful for certain military applications, Avouris says.

The novel physical mechanisms underlying the indium-nitride nanowires' ability to emit light might have wider implications for nanowire research. If the mechanism used here works in other materials, it could expand the number of materials that might be used to create LEDs, Fitzgerald says. That could make LEDs cheaper and give researchers far greater versatility in creating devices with improved performance.

Ultrastrong Paper from Graphene

2007-08-29T08:27:00.001-07:00

A new paperlike material could lead to novel types of light and flexible materials.

By Prachi Patel-Predd

The right stuff: Researchers at Northwestern University have reassembled one-atom-thick graphene sheets that make up soft and flaky graphite crystals in order to create a tough, flexible, paperlike material.
Credit: Dmitriy Dikin

Using graphite--the black flaky stuff employed in pencils--researchers at Northwestern University have created a strong, flexible, and lightweight paperlike material. It could be used as electrolytes or hydrogen storage materials in fuel cells, electrodes in supercapacitors and batteries, and super-thin chemical filters. It could also be mixed with polymers or metals to make materials for use in aircraft fuselages, cars, and buildings.

The new material is made of overlapping layers of graphene, one-atom-thick sheets of carbon atoms arranged in honeycomb-like hexagons. In contrast, graphite, which becomes powdery under pressure, is made of graphene sheets stacked one on top of the other.

Rodney Ruoff, a Northwestern nanoengineering professor who led the work, published in Nature this week, says that the methods behind making the novel graphene paper could lead to even stronger versions. Right now, water molecules hold together the individual 10-nanometer-thick graphene flakes to create the micrometers-thick graphene paper. By using other chemicals as glues, the researchers could make ultrastrong paperlike materials with various properties. "The future is particularly bright because the system is very flexible ... The chemistry is almost infinite," Ruoff says.

Individual sheets of graphene were not known to exist until three years ago, when Andre Geim, a professor of physics at the University of Manchester, in the UK, used adhesive tape to get a few flakes of graphene from a graphite crystal. Researchers still don't understand all of graphene's properties, but they know that it can conduct electrons extremely well and is known to be exceptionally strong. "Graphene is the toughest material in the world--tougher than diamond," Geim says. But in graphite, the graphene sheets are assembled in such a way that they do not bind strongly to each other. So they simply flake off under friction, creating a pencil's black marks.

Ruoff's idea was to "disassemble graphite into individual layers and reassemble them in a different way than they are in graphite." The goal was to find a way to glue the graphene platelets together while reassembling them, which would create a tough and flexible material.

Since it's hard to separate the graphene sheets in graphite, the researchers first used an acid to oxidize graphite and make graphite oxide. Then they put the graphite oxide in water. Individual graphene-oxide sheets easily separated in water.

When the researchers filtered the suspension, the graphene-oxide flakes settled down on the filter, randomly overlapping with each other. Water glued the flakes together; its hydrogen atoms bonded with the carbon atoms in adjacent flakes. The result was a dark-brown, thin, flexible graphene-oxide paper. By adjusting the concentration of graphite oxide in the water, the researchers changed the thickness of the paper, ranging from 1 to 100 micrometers.

In an effort to develop superstrong lightweight materials, others have used carbon nanotubes. And the new graphene-oxide paper is not as strong as carbon-nanotube films, Geim says. "The advantage of materials made from carbon nanotubes is they're much tougher, because they entangle like spaghetti," he says. "When you're dealing with flat sheets, they entangle very little and are breakable."

But the graphene-oxide paper has other key advantages. Graphite is a cheap raw material, and the filtration method is simple and leads to lots of graphene. Most important, the Northwestern researchers' work opens up a way to manipulate graphene sheets and make paperlike materials with different properties.

When Ruoff and his colleagues oxidize graphene into graphene oxide, for instance, the carbon-based material goes from being an electrical conductor to being an insulator. Ruoff says that he can alter graphene's chemistry in other ways to change its electrical properties and make it an insulator, a conductor, or even a semiconductor.

That electrical versatility combines with an ultrastrong material has some observers excited. "They haven't used any tough glue between the [graphene platelets]," Geim says. "I expect very, very tough materials if a proper glue between graphene is used."

Self-Assembling Nanostructures

2007-08-29T08:24:00.001-07:00

Researchers find an easy route to complex nanomaterials.

By Kevin Bullis

No assembly required: Nanorods of cadmium sulfide with silver-sulfide quantum dots (dark spots) form automatically when researchers mix together the right starting chemicals.
Credit: Paul Alivisatos/University of California, Berkeley

Researchers at the University of California, Berkeley, have found an easy way to make a complex nanostructure that consists of tiny rods studded with nanocrystals. The new self-assembly synthesis method could lead to intricate nanomaterials for more-efficient solar cells and less expensive devices for directly converting heat into electricity.

In the structures, the quantum dots are all about the same size and are spaced evenly along the rods--a feat that in the past required special conditions such as a vacuum, with researchers carefully controlling the size and spacing of different materials, says Paul Alivisatos, the professor of chemistry and materials science at Berkeley who led the work. In contrast, Alivisatos simply mixes together the appropriate starting materials in a solution; these materials then arrange themselves into the orderly structure.

Such solution-processing techniques can lead to manufacturing methods in which materials, such as those used in solar cells, are printed on continuous sheets, driving down costs compared with other methods. "Anytime you make something in solution, rather than in a vacuum, it becomes a lot easier and cheaper," says Moungi Bawendi, a chemistry professor at MIT who was not involved in this work.

To make the rods, Alivisatos mixes a combination of methanol and a silver salt into a solution that already contains cadmium-sulfide nanorods. Cadmium ions have a strong affinity for methanol. As a result, when the materials are mixed, the methanol draws cadmium out of the nanorods. Silver ions then fill in the vacant spots left by the cadmium, forming areas of silver sulfide within the rod. At the same time, differences in the crystalline structures of the cadmiun-sulfide rods and the silver-sulfide quantum dots regulate the dots' size and spacing. This is the first time such differences have been used to control the self-assembly of materials in solution.

The nanocrystal-studded rods could prove useful for solar cells and thermoelectric devices that convert heat directly into electricity. For example, in conventional solar cells, each photon only generates a single electron. But certain kinds of quantum dots convert single photons into multiple electrons, which could more than double the efficiency of solar cells. (See "Silicon and Sun.") The problem has been capturing those electrons to create an electrical current. Embedding quantum dots inside rods of another material could help with this problem, says Alivisatos. The quantum dots would absorb the light, while the other material would capture the electrons that the dots generate.

A similar configuration is promising for thermoelectrics, devices that directly convert heat into electricity. The alternating crystal structures in the nanorods could block the transfer of heat while allowing electrons to pass--two key features of such devices.

Having demonstrated the new method for making the structures, Alivisatos and his colleagues are beginning to study the potential photoelectric and thermoelectric properties of the materials. They will likely need to turn to different compounds, such as copper sulfide and cadmium sulfide--a combination that has been used for solar cells in the past, Alivisatos says. There's no guarantee, however, that these materials will form the same orderly structures, or indeed that the structures will perform as the researchers hope they will.

Even if these particular structures do not prove to be the key to low-cost, high-efficiency solar cells, the new self-assembly method for making nanostructures could inspire new materials that are. And Bawendi highlights the need to continue basic research like this to solve today's energy problems. "We don't know what the solution is going to be," he says. But if we create high-quality, carefully described materials as Alivisatos has done, "some of them may be the answer," Bawendi says.

Self-Assembling Nanostructures

2007-08-29T08:24:00.000-07:00

Researchers find an easy route to complex nanomaterials.

By Kevin Bullis

Global 'sunscreen' has likely thinned

2007-08-29T08:15:00.003-07:00

A new NASA study has found that an important counter-balance to the warming of our planet by greenhouse gases sunlight blocked by dust, pollution and other aerosol particles appears to have lost ground.

The thinning of Earths "sunscreen" of aerosols since the early 1990s could have given an extra push to the rise in global surface temperatures. The finding, published recently in the journal Science, may lead to an improved understanding of recent climate change. In a related study published last week, scientists found that the opposing forces of global warming and the cooling from aerosol-induced "global dimming" can occur at the same time.

"When more sunlight can get through the atmosphere and warm Earth's surface, you're going to have an effect on climate and temperature," said lead author Michael Mishchenko of NASA's Goddard Institute for Space Studies (GISS), New York. "Knowing what aerosols are doing globally gives us an important missing piece of the big picture of the forces at work on climate".

The study uses the longest uninterrupted satellite record of aerosols in the lower atmosphere, a unique set of global estimates funded by NASA. Scientists at GISS created the Global Aerosol Climatology Project by extracting a clear aerosol signal from satellite measurements originally designed to observe clouds and weather systems that date back to 1978. The resulting data show large, short-lived spikes in global aerosols caused by major volcanic eruptions in 1982 and 1991, but a gradual decline since about 1990. By 2005, global aerosols had dropped as much as 20 percent from the relatively stable level between 1986 and 1991.

The NASA study also sheds light on the puzzling observations by other scientists that the amount of sunlight reaching Earth's surface, which had been steadily declining in recent decades, suddenly started to rebound around 1990. This switch from a "global dimming" trend to a "brightening" trend happened just as global aerosol levels started to decline, Mishchenko said.

While the Science paper does not prove that aerosols are behind the recent dimming and brightening trends changes in cloud cover have not been ruled out another new research result supports that conclusion In a paper published March 8 in the American Geophysical Union's Geophysical Research Letters, a research team led by Anastasia Romanou of Columbia University's Department of Applied Physics and Mathematics, New York, also showed that the apparently opposing forces of global warming and global dimming can occur at the same time.

The GISS research team conducted the most comprehensive experiment to date using computer simulations of Earth's 20th-century climate to investigate the dimming trend. The combined results from nine state-of-the-art climate models, including three from GISS, showed that due to increasing greenhouse gases and aerosols, the planet warmed at the same time that direct solar radiation reaching the surface decreased. The dimming in the simulations closely matched actual measurements of sunlight declines recorded from the 1960s to 1990.

Further simulations using one of the Goddard climate models revealed that aerosols blocking sunlight or trapping some of the sun's heat high in the atmosphere were the major driver in 20th-century global dimming. "Much of the dimming trend over the Northern Hemisphere stems from these direct aerosol effects," Romanou said. "Aerosols have other effects that contribute to dimming, such as making clouds more reflective and longer-lasting. These effects were found to be almost as important as the direct effects".

The combined effect of global dimming and warming may account for why one of the major impacts of a warmer climate the spinning up of the water cycle of evaporation, more cloud formation and more rainfall has not yet been observed. "Less sunlight reaching the surface counteracts the effect of warmer air temperatures, so evaporation does not change very much," said Gavin Schmidt of GISS, a co-author of the paper. "Increased aerosols probably slowed the expected change in the hydrological cycle".

Whether the recent decline in global aerosols will continue is an open question. A major complicating factor is that aerosols are not uniformly distributed across the world and come from many different sources, some natural and some produced by humans. While global estimates of total aerosols are improving and being extended with new observations by NASA's latest generation of Earth-observing satellites, finding out whether the recent rise and fall of aerosols is due to human activity or natural changes will have to await the planned launch of NASA's Glory Mission in 2008.

"One of Glory's two instruments, the Aerosol Polarimetry Sensor, will have the unique ability to measure globally the properties of natural and human-made aerosols to unprecedented levels of accuracy," said Mishchenko, who is project scientist on the mission.

Posted by: Brooke Source

Sound Waves to Ignite Sun's Ring of Fire

2007-08-29T08:15:00.001-07:00

Researchers have found that the sun's magnetic field allows the release of wave energy from its interior, permitting sound waves to travel through thin fountains, or "spicules", upward and into the chromosphere. The chromosphere is the region of the sun that looks like a red ring of fire during an eclipse.
Credit: Zina Deretsky, National Science Foundation

Sound waves escaping the sun's interior create fountains of hot gas that shape and power a thin region of the sun's atmosphere which appears as a ruby red "ring of fire" around the moon during a total solar eclipse, as per research funded by the National Science Foundation (NSF) and NASA.

The results are presented today at the American Astronomical Society's Solar Physics Division meeting in Hawaii.

This region, called the chromosphere because of its color, is largely responsible for the deep ultraviolet radiation that bathes the Earth, producing the atmosphere's ozone layer.

It also has the strongest solar connection to climate variability.

"The sun's interior vibrates with the peal of millions of bells, but the bells are all on the inside of the building," said Scott McIntosh of the Southwest Research Institute in Boulder, Colo., lead member of the research team. "We've been able to show how the sound can escape the building and travel a long way using the magnetic field as a guide".

The new result also helps explain a mystery that's existed since the middle of the last century -- why the sun's chromosphere (and the corona above) is much hotter than the visible surface of the star. "It's getting warmer as you move away from the fire instead of cooler, certainly not what you would expect," said McIntosh.

"Researchers have long realized that observations of solar magnetic fields are the keys that will unlock the secrets of the sun's interior," said Paul Bellaire, program director in NSF's division of atmospheric sciences, which funded the research. "These scientists have found an ingenious way of using magnetic keys to pick those locks".

Using spacecraft, ground-based telescopes, and computer simulations, the results show that the sun's magnetic field allows the release of wave energy from its interior, permitting the sound waves to travel through thin fountains upward and into the solar chromosphere. The magnetic fountains form the mold for the chromosphere.

Scientists say that it's like standing in Yellowstone National Park and being surrounded by musical geysers that pop up at random, sending out shrill sound waves and hot water shooting high into the air.

"This work finds the missing piece of the puzzle that has fascinated a number of generations of solar astronomers," said Alexei Pevtsov, program scientist at NASA. "If you fit this piece into place, the whole picture of chromosphere heating becomes more clear".

Over the past twenty years, researchers have studied energetic sound waves as probes of the Sun's interior because the waves are largely trapped by the sun's visible surface -- the photosphere. The research observed that some of these waves can escape the photosphere into the chromosphere and corona.

To make the discovery, the team used observations from the SOHO and TRACE spacecraft combined with those from the Magneto-Optical filters at Two Heights, or MOTH, instrument in Antarctica, and the Swedish 1-meter Solar Telescope on the Canary Islands.

The observations gave detailed insights into how some of the trapped waves and their pent-up energy manage to leak out through magnetic "cracks" in the photosphere, sending mass and energy shooting upwards into the atmosphere above.

By analyzing motions of the solar atmosphere in detail, the researchers found that where there are strong knots in the Sun's magnetic field, sound waves from the interior can leak out and propagate upward into its atmosphere.

"The constantly evolving magnetic field above the solar surface acts like a doorman opening and closing the door for the waves that are constantly passing by," said Bart De Pontieu, a scientist at the Lockheed Martin Solar and Astrophysics Laboratory in Palo Alto, Calif.

These results were confirmed by state-of-the-art computer simulations that show how the leaking waves propel fountains of hot gas upward into the sun's atmosphere, and fall back to its surface a few minutes later.

Other research team members are Stuart Jeffries of the University of Hawaii and Viggo Hansteen of the University of Oslo and the Lockheed Martin Solar and Astrophysics Laboratory.

Posted by: Brooke Source

New View of Doomed Star

2007-08-29T08:14:00.001-07:00

Credit: X-ray: NASA/CXC/GSFC/M.Corcoran et al.; Optical: NASA/STScI

Eta Carinae is a mysterious, extremely bright and unstable star located a mere stone's throw - astronomically speaking - from Earth at a distance of only about 7,500 light years. The star is believed to be consuming its nuclear fuel at an incredible rate, while quickly drawing closer to its ultimate explosive demise. When Eta Carinae does explode, it will be a spectacular fireworks display seen from Earth, perhaps rivaling the moon in brilliance. Its fate has been foreshadowed by the recent discovery of SN2006gy, a supernova in a nearby galaxy that was the brightest stellar explosion ever seen. The erratic behavior of the star that later exploded as SN2006gy suggests that Eta Carinae may explode at any time.

Eta Carinae, a star between 100 and 150 times more massive than the Sun, is near a point of unstable equilibrium where the star's gravity is almost balanced by the outward pressure of the intense radiation generated in the nuclear furnace. This means that slight perturbations of the star might cause enormous ejections of matter from its surface. In the 1840s, Eta Carinae had a massive eruption by ejecting more than 10 times the mass of the sun, to briefly become the second brightest star in the sky. This explosion would have torn most other stars to pieces but somehow Eta Carinae survived.

The latest composite image shows the remnants of that titanic event with new data from NASA's Chandra X-ray Observatory and the Hubble Space Telescope. The blue regions show the cool optical emission, detected by Hubble, from the dust and gas thrown off the star. This debris forms a bipolar shell around the star, which lies near the brightest point of the optical emission. This bipolar shell is itself surrounded by a ragged cloud of fainter material. An unusual jet points from the star to the upper left.

Chandra's data, depicted in orange and yellow, shows the X-ray emission produced as material thrown off Eta Carinae rams into nearby gas and dust, heating gas to temperatures in excess of a million degrees. Animation of Massive Star Explosion This hot shroud extends far beyond the cooler, optical nebula and represents the outer edge of the interaction region. The X-ray observations show that the ejected outer material is enriched by complex atoms, particularly nitrogen, cooked inside the star's nuclear furnace and dredged up onto the stellar surface. The Chandra observations also show that the inner optical nebula glows faintly due to X-ray reflection. The X-rays reflected by the optical nebula come from very close to the star itself; these X-rays are generated by the high-speed collision of wind flowing from Eta Carinae's surface (moving at about 1 million miles per hour) with the wind of the companion star (which is about five times faster).

The companion is not directly visible in these images, but variability in X-rays in the regions close to the star signals the star's presence. Astronomers don't know exactly what role the companion has played in the evolution of Eta Carinae, or what role it will play in its future.

Posted by: Brooke Source

Ready for NASA climate change, ozone mission in tropics

2007-08-29T08:13:00.002-07:00

The NASA WB-57 plane will fly into clouds at 60,000 feet during the TC4 mission in Costa Rica, sampling cloud particles and chemistry.

A high-flying NASA mission over Costa Rica and Panama in July and August should help researchers better understand how tropical storms influence global warming and stratospheric ozone depletion, says a University of Colorado at Boulder professor who is one of two mission researchers for the massive field campaign.

Brian Toon, chair of CU-Boulder's atmospheric and oceanic sciences department, said the $12 million effort will mobilize in San Jose, Costa Rica, and involve about 400 scientists, students and support staff operating three NASA aircraft, seven satellites and a suite of other instruments. The team is targeting the gases and particles that flow out of the top of the vigorous storm systems that form over the warm tropical ocean, said Toon.

The warm summer waters of the Pacific Ocean in Central and South America are a breeding ground for heat-driven convective storms targeted by the mission, said NASA officials. Such tropical systems are the major mechanism for Earth's system to loft air into the upper troposphere and stratosphere and are characterized primarily by cumulus clouds with large dense anvils and wispy cirrus clouds.

Known as the Tropical Composition, Cloud and Climate Coupling mission, or TC4, The expedition runs from July 16 through Aug. 8 and is NASA's largest field campaign in several years. The tropical storm systems under study pump air more than 40,000 feet above the surface, where they can influence the make-up of the stratosphere, home of Earth's protective ozone layer.

"This is a very little-studied region of the atmosphere, but it is crucial to understanding global climate change and changes in stratospheric ozone," Toon said.

One mission goal is to understand how transport of chemical compounds - both natural and man-made - occurs from the surface to the lower stratosphere, which is roughly 10 miles in altitude. Another goal is to understand the properties of high-altitude clouds and how they impact Earth' s radiation budget, Toon said.

As a TC4 mission scientist, Toon will be coordinating daily flights of three NASA aircraft filled with scientific instruments that will collect data in concert with NASA satellites. The aircraft include the ER-2 -- NASA's modern version of the Air Force U2-S reconnaissance aircraft -- which can reach an altitude of 70,000 feet and which will fly above the clouds and act as a "surrogate satellite," he said.

The mission also includes a broad-winged WB-57 research plane that will fly into the cirrus clouds at 60,000 feet and sample cloud particles and the make-up of chemicals flowing from massive tropical storm systems. The third plane, a converted DC-8, will fly at about 35,000 feet to probe the region between Earth' s troposphere and stratosphere and sample cloud particles and air chemistry.

"The critical lever in greenhouse warming is water in the upper troposphere," said Toon. "Added water, or more extensive clouds as a result of global warming, would significantly amplify the greenhouse effect from human made pollutants such as carbon dioxide." On the other hand, more extensive convection due to rising sea-surface temperatures could lead to more precipitation and less cloud cover, acting to "retard" greenhouse warming, he said.

Toon and his graduate students will be studying the size and role of ice particles in clouds to better understand how Earth might respond to warming temperatures. "We'd really like to understand the processes that control water as it is going into the stratosphere, which should help improve climate models," he said.

Toon, who spent several years helping to design the NASA mission and chaired the committee that organized the effort, also will be working with CU-Boulder graduate student Charles Bardeen in San Jose on daily weather forecasts, which will help dictate when planes can safely sample in targeted atmospheric regions.

Other participants from CU's oceanic and atmospheric sciences department, or ATOC, include Associate Professor Linnea Avallone, who will work with graduate students to sample water condensed in clouds. Associate Professor Peter Pilewskie and his students will study reflected sunlight from bright clouds to better understand Earth's energy budget in relation to climate change, while Research Associate Frank Evans will study ice cloud properties using radiometry.

Researchers from CU-Boulder's Cooperative Institute for Research in Environmental Sciences -- a joint venture of CU-Boulder and the National Oceanic and Atmospheric Administration -- also will participate in the mission. CIRES and NOAA have 14 scientists involved in the TC4 mission from Boulder.

Observations from a suite of NASA satellites flying in formation, known as the "A-Train," will complement the aircraft measurements. The satellites will measure ozone, water vapor, carbon monoxide and map clouds, charting the aerosol particles inside that affect their formation.

"The potential economic repercussions of global warming are almost unimaginable," said Toon. "We could lose large fractions of entire states over the next century or so if there are significant increases in sea level. "This mission will help us understand Earth's systems and what happens when we modify the planet".

Toon said NASA has a made a huge investment in its satellite fleet over the years and in finally implementing the TC4 mission. "NASA has a commitment to better understand these complex issues," he said. "And our graduate students will probably be writing theses on data from the TC4 mission for the next decade".

Posted by: Tyler Source

Search for 'weird' life

2007-08-29T08:13:00.001-07:00

A new report from the National Research Council, examines the search for life elsewhere in the universe and whether the fundamental requirements for life as we generally know it are the only ways phenomena recognized as "life" could be supported beyond our planet.

Whether "weird" life, as researchers sometimes refer to life with a different biochemical structure than life here, should be considered in the search for extraterrestrial life is looked at in the report.

Posted by: Brooke Source

Life elsewhere in Solar System

2007-08-29T08:12:00.001-07:00

The search for life elsewhere in the solar system and beyond should include efforts to detect what researchers sometimes refer to as "weird" life -- that is, life with an alternative biochemistry to that of life on Earth -- says a new report from the National Research Council. The committee that wrote the report observed that the fundamental requirements for life as we generally know it -- a liquid water biosolvent, carbon-based metabolism, molecular system capable of evolution, and the ability to exchange energy with the environment -- are not the only ways to support phenomena recognized as life. "Our investigation made clear that life is possible in forms different than those on Earth," said committee chair John Baross, professor of oceanography at the University of Washington, Seattle.

The report emphasizes that "no discovery that we can make in our exploration of the solar system would have greater impact on our view of our position in the cosmos, or be more inspiring, than the discovery of an alien life form, even a primitive one. At the same time, it is clear that nothing would be more tragic in the American exploration of space than to encounter alien life without recognizing it".

The tacit assumption that alien life would utilize the same biochemical architecture as life on Earth does means that researchers have artificially limited the scope of their thinking as to where extraterrestrial life might be found, the report says. The assumption that life requires water, for example, has limited thinking about likely habitats on Mars to those places where liquid water is believed to be present or have once flowed, such as the deep subsurface. However, as per the committee, liquids such as ammonia or formamide could also work as biosolvents -- liquids that dissolve substances within an organism -- albeit through a different biochemistry. The recent evidence that liquid water-ammonia mixtures may exist in the interior of Saturn's moon Titan suggests that increased priority be given to a follow-on mission to probe Titan, a locale the committee considers the solar system's most likely home for weird life.

"It is critical to know what to look for in the search for life in the solar system," said Baross. "The search so far has focused on Earth-like life because that's all we know, but life that may have originated elsewhere could be unrecognizable compared with life here. Advances throughout the last decade in biology and biochemistry show that the basic requirements for life might not be as concrete as we thought".

Besides the possibility of alternative biosolvents, studies show that variations on some of the other basic tenets for life also might be able to support weird life. DNA on Earth works through the pairing of four chemical compounds called nucleotides, but experiments in synthetic biology have created structures with six or more nucleotides that can also encode genetic information and, potentially, support Darwinian evolution. Additionally, studies in chemistry show that an organism could utilize energy from alternative sources, such as through a reaction of sodium hydroxide and hydrochloric acid, meaning that such an organism could have an entirely non-carbon-based metabolism.

Scientists need to further explore variations of the requirements for life with particular emphasis on origin-of-life studies, which will help determine if life can exist without water or in environments where water is only present under extreme conditions, the report says. Most planets and moons in this solar system fall into one of these categories. Research should also focus on how organisms break down key elements, as even non-carbon-based life would need elements for energy, structure, and chemical reactions.

The report also stresses that the future search for alien life should not exclude additional research into terrestrial life. Through examination of extreme environments, such as deserts and deep under the oceans, studies have determined that life exists essentially anywhere water and a source of energy are found together on Earth. Field scientists should therefore seek out organisms with novel biochemistries and those that exist in areas where vital resources are scarce to better understand how life on Earth truly operates, the committee said. This improved understanding will contribute greatly toward seeking Earth-like life where the conditions necessary for its existence might be met, as in the case of subsurface Mars.

Space missions will need adjustment to increase the breadth of their search for life. Planned Mars missions, for example, should include instruments that detect components of light elements -- particularly carbon, hydrogen, oxygen, phosphorous, and sulfur -- as well as simple organic functional groups and organic carbon. Recent evidence indicates that another moon of Saturn, Enceladus, has active water geysers, raising the prospect that habitable environments may exist there and greatly increasing the priority of additional studies of this body.

Posted by: Jaison Source

The Planet, the Galaxy and the Laser

2007-08-29T08:11:00.001-07:00

On the night of 21 July, ESO astronomer Yuri Beletsky took images of the night sky above Paranal, the 2600m high mountain in the Chilean Atacama Desert home to ESO's Very Large Telescope. The amazing images bear witness to the unique quality of the sky, revealing not only the Milky Way in all its splendour but also the planet Jupiter and the laser beam used at Yepun, one of the 8.2-m telescopes that make up this extraordinary facility.

"The images are not composite", emphasises Yuri Beletsky. "The camera was being tracked on the stars, which can be easily noticed if you look at the telescope domes on the image (they look a little fuzzy). The colour of the laser beam on the first image actually looks pretty close to what one can see on the sky with the unaided eye."

Most striking in the images is the wide band of stars called the Milky Way. Spanning more than 100 degrees in the first of these images, it shows the dust and stars that are part of our own Galaxy, a spiral galaxy containing about 100 billion stars.

In the middle of this image, two bright objects are also seen. The brighter of the two is the planet Jupiter. The other is the bright star Antares. Another bright star, Alpha Centauri, one of the closest stellar neighbours to the Sun, is visible at the middle-left edge of the image.

Three of the four domes that shelter the 8.2-m VLT's Unit Telescopes are visible on the first image. Streaming out of Yepun, Unit Telescope number 4, is the laser beam used to create an artificial star above Paranal, aiming directly at the centre of our own Galaxy.

At the time the pictures were taken, astronomers were indeed using the SINFONI instrument (see ESO 21/04) to study the Galactic Centre, having a close look at the supermassive black hole that lurks in there.

With so a number of stars visible from the exceptional site of Paranal, one may wonder why it is necessary to create another, artificial, star? The answer lies in the very sophisticated instruments that are used on ESO's VLT. Some of them, such as NACO and SINFONI, make use of adaptive optics, a technique that allows astronomers to overcome the blurring effect of the atmosphere. This means that astronomers obtain images almost as good as if the whole telescope was placed in space, above Earth's atmosphere.

Adaptive optics, however, requires a nearby reference star that has to be relatively bright, thereby limiting the area of the sky that can be surveyed. To surmount this limitation, astronomers now use at Paranal a powerful laser that creates an artificial star, where and when they need it (see ESO 07/06 and 27/07).

Launching such a powerful laser from a telescope is state-of-the-art technology, whose set-up and operation is a continuous challenge. As seen from the images, this is, however, a technology that is now well mastered on Paranal.

The images were obtained with a digital camera and 10-mm optics, mounted on a small equatorial mount, and are each the result of a single 5 minute exposure.

Posted by: Brooke Source

Silicon Lasers Get Up to Speed

2007-08-29T08:02:00.001-07:00

A new silicon-based laser emits the short, high-frequency light pulses that are necessary for today's telecommunications networks.

By Kate Greene
Scintillating silicon: This image illustrates the design for a new hybrid silicon laser. The gray and orange base consists of two layers of silicon sandwiching a layer of silicon dioxide. Indium phosphide, the light-emitting material, is bonded to the top of the silicon with a thin layer of glass glue. Emitted photons bounce back and forth in a channel etched into the top layer of silicon, until they emerge as laser light.
Credit: Peter Allen, University of California, Santa Barbara

Researchers at the University of California, Santa Barbara (UCSB), have designed a silicon-based laser that emits ultrashort pulses of light at high frequencies--two characteristics that are crucial if silicon-based lasers are to become practical. Eventually, the researchers hope that the new laser could replace other, more expensive lasers in optical communication networks. It could even lead to faster computers that shuttle data around using light instead of electricity.

Modern telecommunications networks use three distinct gadgets--lasers, modulators, and detectors--to produce, encode, and detect light. Currently, all three are made of nonsilicon semiconductors, such as indium phosphide, that are difficult to mass-produce; as a consequence, they tend to be expensive and bulky. But if they could instead be made from silicon, they could be integrated on individual chips, says John Bowers, professor of electrical and computer engineering at UCSB. Devices that currently cost hundreds of dollars each could then be made in bulk for pennies, and the cost of bandwidth would plummet. The one snag in the plan is that it's hard to make silicon produce light.

In September 2006, however, the UCSB team and Intel announced a new hybrid laser that, although it still used indium phosphide, was built on a silicon base. (See "Bringing Light to Silicon.") The manufacture of the device began with a wafer that consisted of a layer of silicon dioxide sandwiched between two layers of silicon. In the top layer of silicon, the researchers etched a channel, called a waveguide, within which light bounced back and forth. To the top of the wafer, they bonded strips of indium phosphide, using a layer of glass glue only 25 atoms thick. Adding this additional layer, says Bowers, isn't much different from adding layers of other materials to silicon, something that's regularly done in today's manufacturing process.

To turn the laser on, the researchers applied electrical current to metal contacts on top of the indium phosphide. Indium phosphide is a naturally light-emitting material, so the strips of it on top of the wafer produced photons that got trapped in the channel below, bouncing back and forth along the length of the silicon waveguide. In certain materials, that bouncing is enough to amplify normal light into laser light, but not in silicon. So the device was designed to let a small amount of light, called the evanescent tail, sneak back into the indium phosphide, where it was amplified. The benefit of this design is that it avoids the costly fabrication of an indium-phosphide waveguide.

For the new laser, which is described in a recent issue of Optics Express, the researchers made their design slightly more complex. "We needed to turn it into a device with multiple sections," explains Alexander Fang, a graduate student who worked on the project. He says that he had to make sure the lengths of the cavities were precise, and that regions that amplified light and absorbed light were electrically isolated from each other.

The result is a laser that emits picosecond pulses of light at a frequency of 40 gigahertz. "This thing puts out short pulses of light, which is what you need for high-speed communication," says Bowers. "If you pulse at 40 gigahertz and combine that with a modulator [which puts information onto the light], then you have a light source."

The work "represents some nice progress toward proving a laser source on a silicon wafer," says Ivan Kaminow, professor of electrical engineering and computer science at the University of California, Berkeley, but he cautions that silicon photonics still has a long way to go. "Silicon is not an optimum photonic material," he says. "The hybrid approach is a compromise and, as such, is far from optimum performance." For instance, the hybrid laser can't operate at the same high temperatures that silicon circuits do.

Bowers agrees that there is still work to be done, and improving the device's temperature threshold is on the list. "This is pretty far-out research," he says. "Our goal last year was just to make a good laser on silicon, and now we're expanding that not just to do lasers, but photonic integrated-circuit technology." He suspects that silicon photonic devices based on his group's approach could appear in products as early as 2012.

Networking the Hudson River

2007-08-29T08:01:00.001-07:00

The Hudson could become the world's largest environmental-monitoring system.

By Brittany Sauser
Modeling the Hudson: A new data acquisition and analysis system from IBM will receive data from a network of sensors distributed throughout the Hudson River. The system will examine the data and prioritize it, learning to recognize patterns and trends and automatically focusing resources on areas of interest. The system also includes visualization technologies that, fed with mapping data, can synthesize a virtual river, as shown above. This 3-D model will let researchers observe what is happening in the river in real time and track changes in the ecosystem.
Credit: The Beacon Institute

IBM and the Beacon Institute, a nonprofit scientific-research organization in Beacon, NY, have announced a collaboration with several other research institutions to create an environmental-monitoring system for New York's Hudson River. Their plan is to turn all 315 miles of the river into a distributed network of sensors that will collect biological, physical, and chemical information and transmit it to a central location, where it will be analyzed by IBM's new data acquisition and analysis system. According to John Cronin, CEO of the Beacon Institute, the project is now in its "design phase," which should be complete within a year and a half to two years.

The network's sensors will be deployed in a variety of ways. Some will be mounted on a new robotic underwater vehicle developed by Rensselaer Polytechnic Institute (RPI) and the Woods Hole Oceanographic Institute, both collaborators on the project; the vehicle will be powered by solar cells and can operate either autonomously or under human remote control. Other sensors will be suspended from buoys or fixed in place along the riverbed.

"In terms of having an integrated network of sensors, and given the magnitude of it for the Hudson River, this project is without a doubt a huge advancement and on a much larger scale than anything that has been done before," says Sandra Nierzwicki-Bauer, director of the Darrin Fresh Water Institute at RPI and a member of the science-research committee at the Beacon Institute.

The scale of the network and the variety of its sensors will demand a massive new data-analysis system, which IBM will provide. Comprising both distributed-processing hardware and analytical software, the system is designed to take heterogeneous data from a variety of sources and make sense of it in real time. The software learns to recognize data patterns and trends and prioritizes useful data. If some data stream begins to exhibit even minor variations, the system automatically redirects resources toward it. The system will also be equipped with IBM's visualization technologies; fed with mapping data, they can create a virtual model of the river and simulate its ecosystem in real time.

The IBM system "enables us to do a great deal of work in the area of data integration and data management for very large values and different types of data," says Harry Kolar, Global Alliance executive at IBM. "Another reason we are working in this sensor area is that we can actually build end-to-end solutions, meaning from the smallest device to a large back-end system."

Sensor networks to monitor everything from sewage systems to battlefields have been under development for many years, at companies like Intel, Sun, and Siemens and at academic institutions like the University of California, Los Angeles. But what the "research community has not had is the making-meaning part," says David Culler, a professor of computer science at the University of California, Berkeley. That's what the IBM system is intended to provide.

"A lot of what the research community has been focused on is getting sensors and delivering them through reliable, energy-efficient networks to the computing infrastructure," says Culler. "But once you have the data, what do you do with it, and how do you sort it?"

Much of the data the IBM system will be called upon to sort will be sensor reports on temperature, pressure, salinity, dissolved oxygen content, and pH levels, which will indicate whether pollutants have entered the river. Other sensors will be directed toward sea life, says Nierzwicki-Bauer, and will be used to study species and determine how communities of microscopic organisms change over time.

The exact number of sensors, their types, and their specific locations along the river have not yet been determined. But Cronin says that the sensors will easily number in the many hundreds, and the collaborators plan to develop new sensors along the way. IBM is also working to interconnect the sensors. According to Kolar, fiber-optic cables will be used in some cases and wireless connections in others, depending on Beacon's research requirements. And since the Hudson River flows into the Atlantic Ocean, the river network will be designed with the idea of connecting it to oceanic observatory networks as well.

For Beacon, the project is an opportunity to extract new information from the ecosystem of the river and estuary in order to resolve environmental and policy issues. And what makes the Hudson an unusual subject for environmental monitoring--as well as a challenge to network--is that it is host to lots of human activity, says Cronin. The river is used by tankers, tugboats, barges, recreational vessels, and fishermen, and it's a source of drinking water for six communities. It is also an energy source for sewage treatment plants and industries along the river--in addition to being a home for marine life.

Once the monitoring system is in place, Beacon hopes to extend its efforts globally to create the same type of 24-hour monitoring system in developing countries where rivers are vital to local communities. IBM sees this as a unique opportunity to test and refine some of its advanced hardware and software, as well as develop new technologies for this particular application.

Culler is excited to see IBM involved in an environmental project. "I expect that you are now going to see quite a significant second wave of this [sensor network] technology. We were all really excited about it in 2003, and now in 2007 it is really mature enough that vision can come to reality."

Harvesting Power from the Ocean

2007-08-29T07:59:00.001-07:00

A new technology could generate electricity from waves.

By Kevin Bullis

Wave power: A buoy that generates electricity from the motion of waves. The clear cylinder in the middle of the buoy (see bottom image) contains a roll of rubberlike material that stretches and contracts as the buoy bobs up and down, separating and bringing together electrodes.
Credit: SRI International

Researchers from SRI International, based in Menlo Park, CA, recently completed the first ocean tests of a system that uses a so-called artificial muscle to generate power from the motion of a buoy riding up and down on the waves. Although the prototype produces very little electricity, the researchers say that wave farms based on the technology could eventually rival wind turbines in power output, providing a significant source of clean energy.

Technology for harnessing the ocean's energy already exists, but it has not been widely adopted, largely because it has trouble withstanding the pounding of the waves. The new system could prove both cheaper and more reliable, the researchers say.

Earlier systems used more-conventional electromagnetic devices, such as dynamos with complex transmissions, hydraulic pistons, and turbines. The gears of a transmission, in particular, are vulnerable to wear and tear from the erratic surging of ocean waves.

In contrast, the SRI system is not much more than a sheet of rubber attached to a weight. It has "the mechanical complexity of a rubber band," says SRI senior researcher Roy Kornbluh. As a consequence, it is better able to absorb the shock of waves, says Yoseph Bar-Cohen, a senior research scientist at NASA's Jet Propulsion Laboratory, in Pasadena, CA. What's more, Bar-Cohen adds, the materials that the system is made from are cheap, which could help it compete in price with other sources of electricity.

The polymer-based system at the heart of the new generator is a variation on an artificial muscle--a device developed as an alternative to electric motors in applications such as robots. An artificial muscle will expand or contract when a voltage is applied to it, but the same process can work in reverse: if the muscle is stretched by an outside force, it can generate electricity. A few years ago, SRI developed a small device that, embedded in the heel of a shoe, enabled the wearer to charge a cell phone simply by walking. The wave-harvesting system is basically a larger version of the same technology.

The SRI researchers built their generator by sandwiching a commercially available rubbery material between two electrodes, which are themselves made of a greasy polymer containing conductive materials. The rubber sheet and electrodes are then rolled up, like a scroll, to form a hollow tube. When the tube is pulled by an outside force, the rubber layer is stretched thin, narrowing the gap between the electrodes. Initially, a small battery applies a voltage across the electrodes; when the rubber springs back into its original shape, it forces the electrodes apart, increasing the voltage between them. This excess energy can be siphoned off to generate a current. Part of that current feeds back into the system, so the battery is used only for the first cycle.

The researchers recently tested the system off the coast of Florida. A couple of square meters of rubber rolled into the shape of a hollow tube were attached to a weight and mounted at the center of a buoy. As the buoy bobs in the water, it causes the weight to rise and fall, repeatedly stretching the rubber and allowing it to rebound, generating electricity.

So far, this prototype produces only about five watts of power--enough for a small light bulb. But because the rubber is thin--about 0.1 millimeters thick--it's possible to roll up much more of it and still fit it into the same buoy. A bundle of rubber about a meter long and half a meter thick, with optimized electronics and an improved buoy design, could generate a kilowatt of electricity, Kornbluh says. A string of buoys or larger floating structures could then generate appreciable amounts of electricity. (A thousand buoys could power about 750 houses.) An alternative design could involve submerged sheets of rubber that generate power as the force of currents or tides makes them flap back and forth. Such a system might prove more resilient than the turbines recently used in the East River in New York: their mechanical parts proved unable to withstand tidal forces.

The SRI system produces high voltages, in the range of a kilovolt. That was a problem for the shoe generator, which required a transformer to decrease the voltage enough that it wouldn't fry cell phones and other devices but still had to fit in a shoe. But for the buoy application, high voltage is an advantage, since it makes it more efficient to transmit electricity back to shore along underwater cables. The main challenge moving forward, the researchers say, is to develop a reliable manufacturing process. Their recent tests of the system also underscored the importance of designing new buoys that respond to waves in the best way for generating power. And they'll need to design electronics that, by varying the voltage across the polymer, can modify the stiffness of the system to adapt to different weather conditions.

The system's first commercial applications will likely be in systems for powering navigation, communications, and sensor buoys, and these could come within two years, Kornbluh estimates. But it could be five to ten years before the system can be ramped up for large-scale electricity generation.

"It's very exciting," says Ray Baughman, a professor of chemistry at the University of Texas at Dallas. "It's a promising direction for harvesting energy, not only for remote devices in the ocean but also perhaps for larger-scale energy harvesting."

Silicon Nanocrystals for Superefficient Solar Cells

2007-08-29T07:57:00.000-07:00

Research shows that silicon can wring two electrons from each photon of incoming light.

By Kevin Bullis
Souped-up silicon: A micrograph of a seven-nanometer chunk of crystalline silicon, called a nanocrystal or quantum dot. Such structures could dramatically increase the efficiency of solar cells.
Credit: Arthur Nozik, National Renewable Energy Laboratory

A typical solar cell generates only one electron per photon of incoming sunlight. Some exotic materials are thought to produce multiple electrons per photon, but for the first time, the same effect has been seen in silicon. Researchers at the National Renewable Energy Laboratory (NREL), in Golden, CO, showed that silicon nanocrystals can produce two or three electrons per photon of high-energy sunlight. The effect, they say, could lead to a new type of solar cell that is both cheap and more than twice as efficient as today's typical photovoltaics.

As in earlier work with other materials, the extra electrons come from photons of blue and ultraviolet light, which have much more energy than those from the rest of the solar spectrum, especially red and infrared light. In most solar cells, the extra energy in blue and ultraviolet light is wasted as heat. But the small size of nanoscale crystals, also called quantum dots, leads to novel quantum-mechanical effects that convert this energy into electrons instead.

By generating multiple electrons from high-energy photons, solar cells made of silicon nanocrystals could theoretically convert more than 40 percent of the energy in light into electrical power, says Arthur Nozik, a senior research fellow at NREL. In contrast, today's flat rooftop solar panels are at best just over 20 percent efficient and are theoretically limited to about 30 percent efficiency. Concentrating sunlight with mirrors or lenses could raise that figure to about 40 percent, but the same approach could boost the efficiency of a silicon-nanocrystal solar cell to well over 60 percent, Nozik says.

What's more, solar cells made of silicon nanocrystals could prove to be cheap, giving them a significant advantage over other approaches to high-efficiency solar cells. For example, advanced "multijunction" cells have shown efficiencies of more than 40 percent. But these require complicated manufacturing processes that combine expensive semiconductors optimized for different parts of the solar spectrum. Silicon nanocrystals, in contrast, are relatively easy to make, even compared with the material in conventional solar cells, the best of which are made of very large, single crystals of silicon.

Silicon nanocrystals also have marked advantages over the other nanocrystal materials that have shown the multielectron effect. Some of these materials contain toxic elements such as lead or cadmium, and others rely on elements such as indium that are in limited supply. But silicon is both safe and abundant. It's also well studied, says Christiana Honsberg, professor of electrical and computer engineering at the University of Delaware, so engineers know how to work with it to make solar cells. Indeed, for many of the same reasons, silicon is by far the most common material in solar cells today, and it's attractive as the basis for broader deployment of photovoltaics in the future.

Before the NREL work, researchers had believed that silicon crystals small enough to produce the multielectron effect would be impractical as a photovoltaic material. At the nanoscale, the optical properties of silicon change so that it converts less light from the red end of the spectrum into electrons. As a result, any gains from more efficiently converting blue and ultraviolet light would be offset. Nozik and his colleagues found that the nanocrystals did not have to be as small as was previously thought, skirting this problem.

To be sure, the NREL work is only a first step. Making solar cells that take advantage of multielectron generation is a challenge. That's because the extra electrons are very short-lived, making it difficult to extract them from the nanocrystals to generate an electrical current. Indeed, this has proved so difficult that evidence of the effect has come from indirect methods such as spectroscopy rather than from current generated by a solar cell. The use of the indirect measures has led some prominent experts to question whether the extra electrons are actually being produced, although Nozik says that the effect has been confirmed using multiple techniques. Nozik and his colleagues are now working to make solar cells out of silicon nanocrystals--they're exploring a number of novel designs--and he says they've recently made direct measurements indicating that their cells are releasing multiple electrons per photon absorbed. (Their results have yet to be published.)

Honsberg is cautiously optimistic, calling the finding of the multiple-electron effect in silicon nanocrystals a breakthrough, but only "one breakthrough out of maybe three or four" needed to produce cheap, superefficient solar cells.

A Wirelessly Powered Lightbulb

2007-08-29T07:55:00.000-07:00

Researchers at MIT have created a revolutionary device that could remotely charge batteries and power household appliances.

By Kate Greene
Cutting the cord: MIT researchers have shown that it’s possible to wirelessly power a 60-watt lightbulb from two meters away. Above, a coil (background) creates a magnetic field that is able to pass through an obstruction. The foreground coil resonates at the frequency of the magnetic field, picking up its energy to power the bulb.
Credit: Science

Researchers at MIT have shown that it's possible to wirelessly power a 60-watt lightbulb sitting about two meters away from a power source. Using a remarkably simple setup--basically consisting of two metal coils--they have demonstrated, for the first time, that it is feasible to efficiently send that much power over such a distance. The experiment paves the way for wirelessly charging batteries in laptops, mobile phones, and music players, as well as cutting the electric cords on household appliances, says Marin SoljaÄiÄ‡, professor of physics at MIT, who led the team with physics professor John Joannopoulos.

The research, published in the June 7 edition of Science Express (the online publication of Science magazine), is the experimental demonstration of a theory outlined last November by the MIT team. (See "Charging Batteries without Wires.") "We had strong confidence in the theory," says SoljaÄiÄ‡. "And experiment indeed confirmed that this worked as predicted."

The setup is straightforward, explains Andre Kurs, an MIT graduate student and the lead author of the paper. Two copper helices, with diameters of 60 centimeters, are separated from each other by a distance of about two meters. One is connected to a power source--effectively plugged into a wall--and the other is connected to a lightbulb waiting to be turned on. When the power from the wall is turned on, electricity from the first metal coil creates a magnetic field around that coil. The coil attached to the lightbulb picks up the magnetic field, which in turn creates a current within the second coil, turning on the bulb.

This type of energy transfer is similar to a well-known phenomenon called magnetic inductive coupling, used in power transformers. However, the MIT scheme is somewhat different because it's based on something called resonant coupling. Transformer coils can only transfer power when they are centimeters apart--any farther, and the magnetic fields don't affect each other in the same way. In order for the MIT researchers to achieve the range of two meters, explains SoljaÄiÄ‡, they used coils that resonate at a frequency of 10 megahertz. When the electrical current flows through the first coil, it produces a 10-megahertz magnetic field; since the second coil resonates at this same frequency, it's able to pick up on the field, even from relatively far away. If the second coil resonated at a different frequency, the energy from the first coil would have been ignored.

The researchers' approach, says SoljaÄiÄ‡, also makes the energy transfer efficient. If they were to emit power from an antenna in the same way that information is wirelessly transmitted, most of the power would be wasted as it radiates away in all directions. Indeed, with the method used to transfer information, it would be difficult to send enough energy to be useful for powering gadgets. In contrast, the researchers use what's known as nonradiative energy that is bound up near the coils. In this first demonstration, they showed that the scheme can transfer power with an efficiency of 45 percent.

Wireless power transfer is an idea that's more than 100 years old. In the 1890s, physicist and electrical engineer Nikola Tesla proposed beaming electricity through the air. However, soon thereafter, power cables became the commonly accepted means of transporting electricity across distances. But with the widespread adoption of small, portable devices with batteries in need of constant recharging, people's attention is again turning to wireless power. In fact, the startup Powercast, based in Ligonier, PA, has, using a different approach from that of the MIT team, developed a wireless power system that can transmit low wattages across a distance of about a meter. To start, the company is targeting devices with low power consumption, such as sensors, but it's hoping to ramp up to more power-hungry gadgets in the future.

One concern that people might have, says Sir John Pendry, professor of physics at Imperial College in London, is health effects. "There will be safety issues, real or imagined," he says. "After all, the power has to pass through space in some form or other, and pass through any bodies lying in its path. The [MIT] team has minimized this problem by making sure that the power is mainly in the form of a magnetic field, a form of energy to which the body is almost entirely insensitive."

Based on calculations, SoljaÄiÄ‡ believes that the scheme is safe, even for people with implanted medical devices, such as pacemakers. Although the researchers have not made a detailed study to test how the system interferes with pacemakers, SoljaÄiÄ‡ says that they don't expect it to interact strongly with objects that don't resonate at the same frequencies used to transfer power.

At this point, the team has applied for a number of patents and is planning to commercialize the technology, although the researchers expect that it could take a few years before devices with such wireless power systems will make it to consumers. In the meantime, the team is exploring different materials and alternate coil geometries to try to extend the range and ramp up the power.

Wireless Power

2007-08-29T07:54:00.000-07:00

New physics theory could cut the cord on power chargers for gadgets.

By Kate Greene

One night in 2002, MIT physicist Marin SoljacË‡icÂ´ heard the chirps of his cell phone letting him know that its battery was losing the last of its juice. Annoyed, he began to wonder if there were any physics principles that would allow the phone's battery to be charged in a more convenient way. Over the next three years, SoljacË‡icÂ´, graduate student Aristeidis Karalis, and physics professor John Joannopoulos worked on and off to devise a theoretical scheme for charging gadgets wirelessly.

"We are very good at transmitting information wirelessly," says SoljacË‡icÂ´. But it's been much more difficult to transmit power in the same way, because the radiation spreads out, and most of it is lost in the environment. SoljacË‡icÂ´ and his team propose developing a power "base station" that would plug into a wall, much like a Wi-Fi base station; but it would emit great energy at close range. Theoretically, when devices such as mobile phones or laptops came within range of the power base station, they would pick up its energy.

In the 1890s, before power cables commonly transported electricity over great distances, physicist and electrical engineer Nikola Tesla proposed beaming it through the air. Today, a form of wireless energy transfer called inductive coupling is used to charge electric toothbrushes. Electricity flowing through the wires in a toothbrush's base station produces a magnetic field; that field induces a current in the wires of a nearby toothbrush handle, charging the toothbrush's battery. This technique has limited range, however.

In his wireless energy system, explains SoljacË‡icÂ´, the base station would fill a space with a low-Âfrequency electromagnetic field in the range of a few megahertz. A gadget would be equipped with a receiver, like the power-Âharvesting circuits used in RFID tags to collect ambient energy. SoljacË‡icÂ´'s circuit would be designed to resonate at the same frequency as the radiation emitted by the power station. When the device came within a couple of meters of the station, circuitry would absorb the energy, charging the device's battery. The system could even power household electronics like televisions and toasters.

Most of the radiation emitted from the base station would stay in the viÂcinity, in a surrounding sphere with a radius of only a couple of meters. SoljacË‡icÂ´ says his calculations, and the known health effects of the proposed radio waves, suggest that his wireless power scheme poses no threat to people or other living things.

While the work is still in the realm of theory, SoljacË‡icÂ´ has applied for patents, and the group is working on an experimental demonstration. SoljacË‡icÂ´ says that he envisions houses with power hubs on the ceiling of each room. Then, as long as a mobile phone is inside, it will be charging, not chirping, through the night.

Charging Batteries without Wires

2007-08-29T07:52:00.000-07:00

New MIT research reveals a way to send wireless energy to mobile phones and laptops.

By Kate Greene

Small, battery-powered gadgets make powerful computing portable. Unfortunately, there's still a continual need to recharge the batteries of phones, laptops, cameras, and MP3 players by hooking them up to a tangle of wires. Now researchers at MIT have proposed a way to cut the cords by wirelessly supplying power to devices.

"We are very good at transmitting information wirelessly," says Marin SoljaÄiÄ‡, professor of physics at MIT. But, he says, historically, it's been much more difficult to transmit energy to power devices in the same way. SoljaÄiÄ‡, who was a 2006 TR35 winner (see "2006 Young Innovator"), and MIT colleagues Aristeidis Karalis and John Joannopoulos have worked out a theoretical scheme for a wireless-energy transfer that could charge or power devices within a couple of meters of a small power "base station" plugged into an electrical outlet. They presented the approach on Tuesday at the American Institute of Physics's Industrial Physics Forum, in San Francisco.

The idea of beaming power through the air has been around for nearly two centuries, and it is used to some extent today to power some types of radio-frequency identification (RFID) tags. The phenomenon behind this sort of wireless-energy transfer is called inductive coupling, and it occurs when an electric current passes through wires in, for instance, an RFID reader. When the current flows, it produces a magnetic field around the wires; the magnetic field in turn induces a current in a nearby wire in, for example, an RFID tag. This technique has limited range, however, and because of this, it wouldn't be well suited for powering a roomful of gadgets.

To create a mid-range wireless-energy solution, the researchers propose an entirely new scheme. In it, a power base station would be plugged into an electrical outlet and emit low-frequency electromagnetic radiation in the range of 4 to 10 megahertz, explains SoljaÄiÄ‡. A receiver within a gadget--such as a power-harvesting circuit--can be designed to resonate at the same frequency emitted by the power station. When it comes within a couple of meters of the station, it absorbs the energy. But to a nonresonant device, the radiation is undetectable.

Importantly, the energy that's accessed by the device is nonradiative--that is, it doesn't propagate over great distances. This is due to the low frequency of the radio waves, says John Pendry, professor of physics at Imperial College, in London. Electromagnetic radiation comes in two flavors: near-field and far-field. The intensity of low-frequency radiation drops quickly as a person moves farther away from the base station. In other words, the far-field radiation that propagates out in all directions isn't very strong at low frequencies, hence is essentially useless. (Wi-Fi signals, in comparison, are able to remain strong for tens of meters because they operate at a higher frequency of 2.4 gigahertz.)

However, the near-field radiation, which stays close to the base station, contains quite a bit of energy. "If you don't do anything with it, it just sits there," says Pendry. "It doesn't leak away." This bound-up energy, which extends for a couple of meters, is extracted when a resonant receiver on a gadget comes within range.

At this point, the work is still theoretical, but the researchers have filed patents and are working to build a prototype system that might be ready within a year. Even without a prototype, though, the physics behind the concept is sound, says Freeman Dyson, professor of physics at the Institute for Advanced Study, in Princeton, NJ. "It's a nice idea and I have no reason to believe that it won't work."

Pendry suspects that people might be squeamish about the idea of wireless energy radiating throughout the air. "Whenever there's powerful energy sources, people worry about safety," he says. Depending on the application, he says, either the electric or the magnetic portion of the near-field radiation could be handy. Using the electric field would pose a health risk, and would be better employed in applications in which people aren't nearby, he says. Conversely, using the magnetic field would be much safer and could be implemented just as easily. "I can't think of any reason to worry [about health concerns]," he says, "but people will."

SoljaÄiÄ‡ also suspects that the wireless power systems would be safe, based on his calculations and on the known health effects of low-frequency radio waves.

Ideally, says SoljaÄiÄ‡, the system would be about 50 percent as efficient as plugging into an outlet, which would mean that charging a device might take longer. But the vision for this sort of wireless-energy setup, he says, is to place power hubs on the ceiling of each room in the house so that a phone or laptop can be constantly charging from any location in a home.

A More Efficient Engine

2007-08-28T10:47:00.000-07:00

A new type of engine could be relatively inexpensive.

By Kevin Bullis

A new version of the internal combustion engine, which could significantly cut gas consumption, might be surprisingly practical and easy to deploy, according to recent findings by researchers at MIT. Tests on a prototype based on the technology, which allows engines to switch between conventional technology and the new gas-saving type of combustion, show that it does not require a special fuel, and engines using the technology can be cheaply made out of conventional auto parts.

The gas-saving technology, called homogeneous charge compression ignition, or HCCI, uses a form of combustion that is much more efficient than conventional spark ignition. Under some conditions, it can reduce fuel consumption by 25 percent, says William Green, a professor of chemical engineering at MIT who was coauthor of the new study. That's very similar to the efficiency of a diesel engine, which also achieves combustion by compression rather than a spark. But unlike diesel engines, HCCI results in a more uniform combustion and is thus much cleaner. A system that combines HCCI with conventional combustion could improve fuel economy by a few miles per gallon on average, Green says.

Several research groups are working on the new type of combustion. Volvo, for example, has built a hybrid system that can switch between conventional spark ignition and HCCI. Some experts, however, had expected that the new type of engine would require special fuel.

The MIT research shows that an HCCI engine can operate with any of the varieties of gasoline sold in North America, making a special fuel unnecessary. The researchers tested a range of different gasolines made at different refineries. They found that the HCCI engine "was less sensitive to the fuel than people had feared," says Green.

While the HCCI has several performance limitations, these can be addressed using a hybrid approach, in which an engine could switch between HCCI and conventional spark ignition. Using already mass-produced parts could make it relatively inexpensive to build such a hybrid, Green says.

In conventional gasoline engines, a spark ignites a mixture of fuel and air in a combustion chamber, creating an explosion that drives a piston. While this happens very efficiently when the engine is working hard, it's less efficient at lower loads, such as during cruising, when less gasoline is being pumped into the combustion chamber. At these times, to keep the ratio of fuel to oxygen optimized, a partial vacuum is created in the chamber. It takes extra energy to make this vacuum, which decreases the engine's efficiency.

The HCCI technology avoids the use of an energy-wasting vacuum. Instead, hot gases from a previous combustion cycle remain in the chamber; the engine uses a combination of heat from these hot gases and heat generated by compressing the mixture to raise temperatures high enough that the mixture explodes.

But if the engine's temperature is too low, such as when it's being started or being operated under very low loads, the mixture doesn't get hot enough to combust. And at high loads, when the temperature is high, the mixture can combust too early, out of sync with the cycling of the engine, causing a potentially damaging phenomenon called knock. Differences in fuels can also affect precisely when the mixture combusts.

The hybrid system switches between the two forms of combustion. To do this requires changing the way the engine deals with combusted gases. During spark combustion, the gases are forced out through an open valve. In HCCI, the timing of the opening of that valve is changed so that it closes before the gases completely escape, trapping them inside.

John Heywood, a professor of mechanical engineering at MIT who was not involved with this work, says that HCCI could eventually provide even greater benefits as researchers find ways to adapt the engine so that they can use it for a wider range of loads. What's more, it could be used in combination with other gas-saving technologies already available on many vehicles. The extent to which HCCI can be combined with other approaches could determine how widely it's adopted, suggests Heywood.

More Efficient Solar Cells

2007-08-28T10:38:00.000-07:00

Researchers are using layers of silicon quantum dots to create ultra-efficient silicon solar cells.

By Kate Greene

Scientists who work with solar cells are constantly looking for ever-more-efficient materials and engineering approaches that are better able to convert sunlight into electricity. Now, researchers at the University of New South Wales, in Sydney, Australia, have completed the preliminary steps in making an all-silicon structure that can, in theory, eke out nearly twice the electricity that traditional silicon solar cells--the industry's mainstay--can.

To maximize efficiency, Martin Green, lead researcher on the project and professor of photovoltaic- and renewable-energy engineering, and his team are developing a multilayered silicon system that converts varying wavelengths of sunlight into electricity. Each layer is tuned to collect light at a certain wavelength, says Green.

Multilayered systems--commonly used by NASA to power satellites--have been studied for years. Currently, these systems can operate at an efficiency of about 30 percent. By comparison, the best single-layer silicon cells in research labs have an efficiency of 25 percent. However, the multilayer cells are often made from stacks of exotic semiconductor materials composed of gallium, indium, phosphorous, and arsenic. These materials, Green notes, are expensive and not practical to mass-produce on the scale that's necessary for solar power to compete with other sources of power generation.

So, Green and his team turned to silicon--inexpensive and abundant, but traditionally bypassed when making multilayered solar cells--to see if they could control the material's electronic and optical properties so that it could absorb different wavelengths of light. They used a method that mixes small amounts of silicon with silicon dioxide, silicon carbide, or silicon nitride. When heated, the silicon precipitated out into quantum dots--tiny crystals that absorb different wavelengths of light, depending on their size. The researchers then showed that they could make the silicon quantum dots, which are sandwiched within the layers, in different sizes, depending on the thickness of the layer.

The researchers tuned the dots to absorb light at wavelengths from about 1,100 nanometers (infrared light) to roughly 600 nanometers (red light). For the complete solar cell to work, the layers of quantum dots would need to be stacked according to their size. The top layer would contain the smallest dots, which absorb the shortest wavelength. The rest of the light passes through to the layers below, which would contain subsequently larger dots. Green's proposed scheme contains three of these quantum-dot layers.

There is still much work to be done, however, to turn the results and underlying concept into a viable solar cell. When light is absorbed by the quantum dots, electrons are generated, but the researchers still can't control how those electrons travel through the layers. The team is working on modifying the system so that the electrons can be transported from the quantum dots to metal contacts to generate electricity. The team expects to have worked out the majority of the remaining challenges and to have a working cell within two years.

The "all-silicon approach" is more amenable to large-scale manufacturing than is using the more exotic materials for multilayered cells, says Ryne Raffaelle, professor of physics and director of the NanoPower Research Labs at the Rochester Institute of Technology, in NY. For many years, Raffaelle adds, researchers who have been looking toward the future of solar technology have been exploring inexpensive thin films and new materials. But, he says, if Green is successful, "silicon may rise once again to the pinnacle of [solar-cell] conversion efficiency."

In an arena of technology that is filled with new approaches, solar-cell experts are taking a wait-and-see attitude about whether the initial optical experimental results will hold up in an actual device. "It will take a lot of work to realize the predicted high efficiencies" of the multilayered silicon quantum-dot cell, says Arthur Nozik, senior research fellow at the U.S. DOE National Renewable Energy Laboratory. But, he says, the concept is promising, and it's a "very worthwhile research effort."

Source: http://www.technologyreview.com

The Invisible Hearing Aid

2007-08-28T10:34:00.001-07:00

A fully implantable device is poised to change the world of hearing loss--but is it worth the risks that are associated with the required surgery?

By Michael Chorost

Listen in: Otologics’s fully implantable hearing aid is countersunk into the skull so that it lies flush along the surface underneath the skin and muscle.
Credit: Otologics

Hearing aids help millions of people, but many resist them because they think wearing one carries a social stigma. Hearing aids also have serious lifestyle limitations: the hearing impaired can't wear them while showering or swimming, and most models are hard to wear while sleeping. Now, a new kind of hearing aid that aims to overcome these problems is in clinical trials. It's invisible and waterproof because all of its circuitry--including its battery and microphone--is in the user's head.

Developed by Otologics, of Boulder, CO, the device picks up sound with a microphone implanted underneath the skin behind the user's ear. The signal is processed by electronics and sent to a tiny vibrating piston implanted against the small bones in the middle ear. The bones transmit the vibrations to the inner ear, which encodes them as nerve impulses and sends the information to the brain.

"You can have a more normal life," says Otologics's CEO José Bedoya. "You can be exposed to environments in which hearing aids have difficulty operating properly." He also suggests that implantation creates a psychological bond with the device that is life enhancing. "Individuals implanted with the system have said that it becomes a part of you--there's a greater sense of security."

The device is powered by a battery that is recharged when the user places a small radio transmitter against his or her head for 60 to 90 minutes. The transmitter is held to the skin by a magnet in the implant. An inductive coil in the implant converts the radio energy to electricity and recharges the battery with it. The battery can stay inside the body for at least five years, according to the company, before it needs to be replaced. The implanted components are hermetically sealed together to protect against leaks, so the electronics, microphone, and inductive coil are replaced as well. However, the piston in the middle ear remains in place.

The results of a phase I clinical trial of the hearing aid were reported in the August 2007 issue of Otolaryngology--Head and Neck Surgery. Twenty subjects with moderate to severe hearing loss were implanted in one ear. (Seventeen of the subjects had worn conventional hearing aids prior to the study.) The subjects did somewhat worse than with the hearing aid they had previously worn: their ability to hear a range of single-frequency tones dropped between 5 and 12 decibels, and mean word-recognition scores dropped from the low 80 percent range to the high 60 percent range.

On the other hand, a satisfaction survey found that the subjects felt that the device not only improved their hearing, but also sounded more natural than their old hearing aid. The authors of the study speculated that new processing algorithms would improve the test results. Otologics has indicated that it is already working on this.

A key challenge in developing a fully implantable hearing aid is designing a microphone that will work effectively under the skin. Bedoya notes that the properties of human skin change throughout the day with the user's hydration levels and other factors, and he hinted that the company is developing technology to detect those changes and adjust to them. He also points out that the location of the microphone behind the ear is an important factor that can be fine-tuned.

Outside experts see significant progress being made in implantable microphone design. Joseph Roberson, an ear surgeon and the CEO of the California Ear Institute, in Palo Alto, CA, says, "I listened to a good-fidelity musical signal received by an implantable microphone positioned under half an inch of raw steak." The functional outcome of the Otologics device, he says, is "roughly equivalent to existing visible external technology."

But critics question whether Otologics can match the performance of conventional hearing aids, and they ask whether the new device is worth the surgical risk and the cost ($19,000 in Europe, excluding the cost of the surgery, versus $6,000 for a high-end conventional aid; the device is available in Europe but still in clinical trials in the United States). Gerald Loeb, a professor of biomedical engineering at the University of Southern California, argues that implanted hearing aids should outperform conventional ones before they can be considered worth the extra cost and risk. He also questions the emphasis on making an invisible device: "How big an issue is it to have a little appliance on your ear when the whole world is walking around with cell-phone headsets and iPod earpieces?"

Nonetheless, the phase I study concluded that the Otologics device "serves as a viable treatment alternative for moderate to severe sensorineural hearing loss." Bedoya says that the company is addressing the problems found by the study and preparing for phase II trials, in which 90 subjects will be tested with a revised device.

Roberson suggests that the device may be most suitable for "alpha adopters ... who are motivated to keep their use of a hearing device a private matter, or those who are intolerant of standard hearing-aid technology." Silicon Valley executives, he thinks, may be first in line.

Michael Chorost is the author of Rebuilt: How Becoming Part Computer Made Me More Human.

Source: http://www.technologyreview.com

Puke-inducing Flashlight

2007-08-28T10:32:00.000-07:00

Aug 08, 2007

This flashlight will surely help you to protect your house from robbers or it can help police arrest criminals. This cool gadget has been developed by Intelligent Optical Systems and it blinds its target temporarily when you flash the target person with its strong beam.

Blind person becomes disoriented and very dizzy which can make him puke. A disoriented person will be an easy target for police officers and they will be able to take them in custody.

Blinding a person temporarily is a very good way to make him weak. However, how that happens? The whole process happens thanks to very bright LEDs. They pulse and flash while changing its colors. This process is very fast so your eyes do not know what happens and this light blinds you for some time.

The only way to protect yourself from this flashlight's beam is to ether look away or to close your eyes. However, it is hard to run away when your eyes are closed. Just make sure you don’t have a good meal just before you attempt to break into a home.

Source: www.Gadgets-reviews.com

Emergency Phone Charger for Real Optimists

2007-08-28T10:28:00.000-07:00

Aug 08, 2007

Murphy's Law is an adage in Western culture that broadly states that things will go wrong in any given situation, if you give them a chance. The book " Murphy's law " issued in 1977 had stunning success. I think that the reason for that is that the world is full of such pessimistic people, as the man, whose name this gloomy law inherited. Serving at Air Force Base, the captain Edward Murphy, investigated the reasons why the planes crash. He came to pessimistic conclusion that if there was only one way to do something wrong, the technologists would find it.

One more of Murphy's laws asserts that if four reasons of possible troubles are eliminated beforehand, there will always be fifth. Certainly, these laws are basically created for pessimists. But I hope you would agree that when you get in a trouble, and you can's find a way out no matter how hard you try, you start to believe that Murphy was somehow right.

I do not offer you to join a special club for pessimists. I just hope it is still possible to avoid such situation, when your telephone with its death breaks your connection with the world right at that moment when you need it the most. Such small portable gadget like Emergency Phone Charger gives you an opportunity to charge the telephone for 2 hours of extra talking time. Thus, if your telephone ran out of charge and interrupted an important conversation when you find yourself far from home, using a single AA battery, you can return it to life and continue the talk.

Different things happen and every day we have to face a lot of difficult situations. After some unpleasant incidents it is difficult to be sure that everything will finally be fine. Still you may use the chance and carry with you Emergency Phone Charger which size is approximately 7cm (H) x 2cm (W) x 2cm (D). It is necessary to be always on the check! It is better to believe in good, and then the laws of Murphy will be left behind!

Contents:

1x Emergency Phone Charger

4x Phone adapter leads

Features:

Highly portable, instant phone charger.
A powerful charging with a single AA battery gives you up to 2 hrs extra talking time.
The charge time is the same as for your mains-pluggable charger and may vary depending on your handset.

To charge your mobile:

Load a single AA battery into the charger.
Connect your phone to the charger using the compatible plug.
Connect the charger's plug with your mobile phone.
Your phone should be showing now the "charging" status

Buy Emergency Phone Charger

www.Gadgets-reviews.com

ISIS! Unlock the mystery and find the hidden treasure!

2007-08-28T10:25:00.000-07:00

The Egyptian pyramids found on the list of 7 miracles of the world are surrounded by a great deal of secrets and legends. Some unknown forces protect these huge structures and do not allow anyone to penetrate into the heart of the history and culture of the ancient Egyptians, or break silence of great kings' tombs. May be, these are the powerful Egyptian gods, may be the art of placing traps perfectly mastered by wise priests.

Nobody knows for sure how long the pyramids will remain riddles for mankind, but it is known that Andrew Reeves, inspired by the pyramids and an Egyptian goddess, managed to create a fascinating and very complicated game - riddle. The game is named in honor of the Egyptian goddess of the sky and nature - Isis. Andrew Reeves, the father of Isis puzzle, invested over 3 years and more than 200,000 pounds in the development of the game. Andrew created surely the most difficult puzzle of all time that is almost impossible to crack!

The Isis puzzle is an interactive mind game created for players who have to open a metal ball which is constructed in layers and covered with Egyptian symbols. The task is to break the code and reveal a special key inside by moving details of the ball. The key has a number stamped on it. It must be used to open one of the ISIS golden pyramids.

These pyramids are located throughout the UK, each of them contains a gold coin, if you are the first who finds it and a silver one for the next finders. It is really interesting that every Isis puzzle is hand-crafted in the UK, and the latest engineering technologies are used to ensure a high level of quality and precision.

The final role in design of the Ball is played by a solid wooden box with a high polish finish, in which the ball is placed. The designers of the ISIS are so confident of its supreme difficulty that they've put cash prizes for those who manage to break the ISIS code. And, that is what the creator himself says about his brainchild, 'The ISIS appeared as the result of continuous research and development . There are about millions of combinations. The game challenges the most intellectual of minds. The game may become a real obsession and you get restless until you crack the code.... '

And what about you? Do you think it is possible? Would you like to break open the code, check up yourself and your opportunities?

Source: www.Gadgets-reviews.com

Whether a CD player can be much smaller than a disk?

2007-08-28T10:22:00.000-07:00

Involve the imagination! How should look a CD player and whether it can be much smaller than a disk? It is incredible, but fact! Thanking designer Yong-Seong Kim to our attention has appeared the most improbable gadget, using which is possible to listen not only MP3, but also CD files. This musical player reminds me, as to the girl, wings of the butterfly sitting on a flower, and the men name this player "butterfly knife ".

Concerning other CD players it weighs as a butterfly and occupies as much space as a butterfly would. So it can be conveniently clipped on your jeans or placed in the pocket.

Extending the “butterfly’s wings” of the Bufferly Knife-Style MP3/CD Player, put in your CD and expect music, surprised sights and even gazes. Be stylish with extremely cool gadget.

Buy CD Player now

Source: www.Gadgets-reviews.com

Gaping "Hole" in the Sky Found, Experts Say

2007-08-26T21:49:00.000-07:00

Mason Inman
for National Geographic News
August 24, 2007

There is a yawning gap of sky nearly a billion light-years across that contains no matter, a new study suggests.

But some researchers aren't buying it, in part because it would be a monumental surprise to find a void that large.

When seen on the scale of tens of millions of light-years, the universe has a foamy structure, with galaxies arranged as if on strings or sheets, with little matter in between them.

This arrangement applies to both visible matter that pumps out light, such as stars, and the mysterious dark matter, whose existence can be inferred only indirectly from how it holds galaxies together.

(Related: "'Cosmic Train Wreck' May Derail Theories of Dark Matter" [August 22, 2007].)

But at much larger scales, about 150 million light-years and beyond, researchers had expected the universe would be more uniform—so finding a void nearly a billion light-years across was a shock.

"Not only has no one ever found a void this big, but we never even expected to find one this size," said study lead author Lawrence Rudnick of the University of Minnesota in Minneapolis.

Rudnick and colleagues Shea Brown and Liliya Williams report their findings in a paper accepted for publication in the Astrophysical Journal.

Unusual Spot of Sky

The researchers began looking at this particular spot in the sky because it already showed a strange feature.

There the cosmic microwave background radiation—low-level light left over from the birth of our universe that bathes all of space—is especially dim.

This dark patch—where the sky appears "cooler"—is known as the "WMAP cold spot," named after the Wilkinson Microwave Anisotropy Probe satellite that mapped the radiation in 2003.

The cold spot was surprising, because background radiation is remarkably uniform across the whole sky, interrupted only by small bumps and dips.

So Rudnick looked across the sky at galaxies that emit radio waves. He also tracked what the radio signals were like in the region of the WMAP cold spot to find a reason for the radiation dip.

Possible explanations included that the dip is a holdover from the beginnings of the universe or that a cosmic cloud is soaking up the radiation before it could reach Earth. (Related: "Proof of Big Bang Seen by Space Probe, Scientists Say" [March 17, 2006].)

But Rudnick found that in this region of the sky, there are also far fewer sources of radio waves.

The research team interpreted this as a huge void empty of both regular and dark matter that's nearly a billion light-years across.

"Although our surprising results need independent confirmation, the slightly lower temperature of the [radiation] in this region appears to be caused by a huge hole devoid of nearly all matter," Rudnick said. This hole is estimated to be about six to ten billion light-years away from Earth.

Open to Interpretation?

But some other researchers aren't convinced by this interpretation.

"The claims ... are interesting and important if correct," said Margaret Geller of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts. "But the argument for such a large completely empty void in the universe is not thoroughly convincing.

"Even the smaller voids detected in a wide variety of surveys are not completely empty," Geller added. "It is also odd that there are no other solid indications of structures approaching this scale."

"For this surprising finding to be taken seriously, more objects of comparable size should be found, something that is certainly not to be expected according to the standard model [of cosmology]," said Pablo Fosalba of the Autonomous University of Barcelona in Spain.

Yet the debate could be resolved soon.

The Planck satellite, due to launch in 2008, will produce "very clean extragalactic maps that will greatly help in resolving this puzzle," Fosalba said.

Global Warming Video

2007-08-26T21:35:00.000-07:00

Global Warming
July 2006
Scientists speak out about the threat and how to deal with it.
(6min 10sec)

Source: http://www.technologyreview.com/

Mining the Moon

2007-08-26T21:28:00.000-07:00

Lab experiments suggest that future fusion reactors could use helium-3 gathered from the moon.
By Mark Williams

Hot gases: Researchers at the University of Wisconsin-Madison’s Fusion Technology Institute are testing this fusion reactor, shown with a view of the grid in which interial electrostatic confinement takes place. Credit: Fusion Technology Institute-University of Wisconsin-Madison

At the 21st century's start, few would have predicted that by 2007, a second race for the moon would be under way. Yet the signs are that this is now the case. Furthermore, in today's moon race, unlike the one that took place between the United States and the U.S.S.R. in the 1960s, a full roster of 21st-century global powers, including China and India, are competing.
Even more surprising is that one reason for much of the interest appears to be plans to mine helium-3--purportedly an ideal fuel for fusion reactors but almost unavailable on Earth--from the moon's surface. NASA's Vision for Space Exploration has U.S. astronauts scheduled to be back on the moon in 2020 and permanently staffing a base there by 2024. While the U.S. space agency has neither announced nor denied any desire to mine helium-3, it has nevertheless placed advocates of mining He3 in influential positions. For its part, Russia claims that the aim of any lunar program of its own--for what it's worth, the rocket corporation Energia recently started blustering, Soviet-style, that it will build a permanent moon base by 2015-2020--will be extracting He3.
The Chinese, too, apparently believe that helium-3 from the moon can enable fusion plants on Earth. This fall, the People's Republic expects to orbit a satellite around the moon and then land an unmanned vehicle there in 2011.
Nor does India intend to be left out. (See "India's Space Ambitions Soar.") This past spring, its president, A.P.J. Kalam, and its prime minister, Manmohan Singh, made major speeches asserting that, besides constructing giant solar collectors in orbit and on the moon, the world's largest democracy likewise intends to mine He3 from the lunar surface. India's probe, Chandrayaan-1, will take off next year, and ISRO, the Indian Space Research Organization, is talking about sending Chandrayaan-2, a surface rover, in 2010 or 2011. Simultaneously, Japan and Germany are also making noises about launching their own moon missions at around that time, and talking up the possibility of mining He3 and bringing it back to fuel fusion-based nuclear reactors on Earth.
Could He3 from the moon truly be a feasible solution to our power needs on Earth? Practical nuclear fusion is nowadays projected to be five decades off--the same prediction that was made at the 1958 Atoms for Peace conference in Brussels. If fusion power's arrival date has remained constantly 50 years away since 1958, why would helium-3 suddenly make fusion power more feasible?
Advocates of He3-based fusion point to the fact that current efforts to develop fusion-based power generation, like the ITER megaproject, use the deuterium-tritium fuel cycle, which is problematical. (See "International Fusion Research.") Deuterium and tritium are both hydrogen isotopes, and when they're fused in a superheated plasma, two nuclei come together to create a helium nucleus--consisting of two protons and two neutrons--and a high-energy neutron. A deuterium-tritium fusion reaction releases 80 percent of its energy in a stream of high-energy neutrons, which are highly destructive for anything they hit, including a reactor's containment vessel. Since tritium is highly radioactive, that makes containment a big problem as structures weaken and need to be replaced. Thus, whatever materials are used in a deuterium-tritium fusion power plant will have to endure serious punishment. And if that's achievable, when that fusion reactor is eventually decommissioned, there will still be a lot of radioactive waste.
Helium-3 advocates claim that it, conversely, would be nonradioactive, obviating all those problems. But a serious critic has charged that in reality, He3-based fusion isn't even a feasible option. In the August issue of Physics World, theoretical physicist Frank Close, at Oxford in the UK, has published an article called "Fears Over Factoids" in which, among other things, he summarizes some claims of the "helium aficionados," then dismisses those claims as essentially fantasy.
Close points out that in a tokamak--a machine that generates a doughnut-shaped magnetic field to confine the superheated plasmas necessary for fusion--deuterium reacts up to 100 times more slowly with helium-3 than it does with tritium. In a plasma contained in a tokamak, Close stresses, all the nuclei in the fuel get mixed together, so what's most probable is that two deuterium nuclei will rapidly fuse and produce a tritium nucleus and proton. That tritium, in turn, will likely fuse with deuterium and finally yield one helium-4 atom and a neutron. In short, Close says, if helium-3 is mined from the moon and brought to Earth, in a standard tokamak the final result will still be deuterium-tritium fusion.
Second, Close rejects the claim that two helium-3 nuclei could realistically be made to fuse with each other to produce deuterium, an alpha particle and energy. That reaction occurs even more slowly than deuterium-tritium fusion, and the fuel would have to be heated to impractically high temperatures--six times the heat of the sun's interior, by some calculations--that would be beyond the reach of any tokamak. Hence, Close concludes, "the lunar-helium-3 story is, to my mind, moonshine."
So, is He3-based fusion untenable? In fact, Close is correct in his claims about how impracticable both deuterium-helium-3 fusion and pure helium-3 fusion in tokamak-based reactors would be. But there might be alternatives. For example, Gerald Kulcinski, a professor of nuclear engineering at the University of Wisconsin-Madison, has maintained the only helium-3 fusion reactor in the world on an annual budget that's barely into six figures.
Kulcinski's He3-based fusion reactor, located in the Fusion Technology Institute at the University of Wisconsin, is very small. When running, it contains a spherical plasma roughly 10 centimeters in diameter that can produce sustained fusion with 200 million reactions per second. To produce a milliwatt of power, unfortunately, the reactor consumes a kilowatt. Close's response is, therefore, valid enough: "When practical fusion occurs with a demonstrated net power output, I--and the world's fusion community--can take note."
Still, that critique applies equally to ITER and the tokamak-based reactor effort, which also haven't yet achieved breakeven (the point at which a fusion reactor produces as much energy as it consumes). What's significant about the reactor in Wisconsin is that, as Kulcinski says, "We are doing both deuterium-He3 and He3-He3 reactions. We run deuterium-He3 fusion reactions daily, so we are very familiar with that reaction. We are also doing He3-He3 because if we can control that, it will have immense potential."
The reactor at the Fusion Technology Institute uses a technology called inertial electrostatic confinement (IEC). Kulcinski explains: "If we used a tokamak to do deuterium-helium-3, it would need to be bigger than the ITER device, which already is stretching the bounds of credibility. Our IEC devices, on the other hand, are tabletop-sized, and during our deuterium-He3 runs, we do get some neutrons produced by side reaction with deuterium." Nevertheless, Kulcinski continues, when side reactions occur that involve two deuterium nuclei fusing to produce a tritium nucleus and proton, the tritium produced is at such a higher energy level than the confinement system that it immediately escapes. "Consequently, the radioactivity in our deuterium-He3 system is only 2 percent of the radioactivity in a deuterium-tritium system."
More significant is the He3-He3 fusion reaction that Kulcinski and his assistants produce with their IEC-based reactor. In Kulcinski's reactor, two helium-3 nuclei, each with two protons and one neutron, instead fuse to produce one helium-4 nucleus, consisting of two protons and two neutrons, and two highly energetic protons.
"He3-He3 is not an easy reaction to promote," Kulcinski says. "But He3-He3 fusion has the greatest potential." That's because helium-3, unlike tritium, is nonradioactive, which, first, means that Kulcinski's reactor doesn't need the massive containment vessel that deuterium-tritium fusion requires. Second, the protons it produces--unlike the neutrons produced by deuterium-tritium reactions--possess charges and can be contained using electric and magnetic fields, which in turn results in direct electricity generation. Kulcinski says that one of his graduate assistants at the Fusion Technology Institute is working on a solid-state device to capture the protons and convert their energy directly into electricity.
Still, Kulcinski's reactor proves only the theoretical feasibility and advantages of He3-He3 fusion, with commercial viability lying decades in the future. "Currently," he says, "the Department of Energy will tell us, 'We'll make fusion work. But you're never going to go back to the moon, and that's the only way you'll get massive amounts of helium-3. So forget it.' Meanwhile, the NASA folks tell us, 'We can get the helium-3. But you'll never get fusion to work.' So DOE doesn't think NASA can do its job, NASA doesn't think that DOE can do its job, and we're in between trying to get the two to work together." Right now, Kulcinski's funding comes from two wealthy individuals who are, he says, only interested in the research and without expectation of financial profit.
Overall, then, helium-3 is not the low-hanging fruit among potential fuels to create practical fusion power, and it's one that we will have to reach the moon to pluck. That said, if pure He3-based fusion power is realizable, it would have immense advantages.
Source: http://www.technologyreview.com

Apple's iPhone

2007-08-26T21:07:00.000-07:00

An inside look at a sensation.
By Daniel Turner

Credit: Photography by Christopher Harting

Apple's latest offering proves that revolutionary tech products don't have to be that revolutionary. Upon the iPhone's release, enthusiasts around the world rushed to tear it apart, eager to see something new. Instead, they found that Apple had relied mostly on tried-and-true components--with one big exception: a truly stunning multitouch screen that allows users to manipulate data and images in entirely unprecedented ways.
Two BoardsOne of the iPhone's two circuit boards includes the CPU, the flash memory, and other system memory chips that allow the phone to run its stripped-down version of Apple's OS X operating system and serve as a media device. The other board hosts the elements that enable communications: chips from Infineon that provide connectivity over GSM (global system for mobile) and EDGE (enhanced data rates for GSM evolution) mobile-phone networks, as well as an 802.11b/g chip from Marvell. Howard Curtis, the VP of global services at Portelligent, which analyzes electronic products, says this design leaves Apple with options. "You could isolate changes to one board and swap it out," he says--say, to provide support for CDMA, another popular mobile-phone standard.
Communications CenterThe chips that make the iPhone a phone "seem to be pretty standard," says Kyle Wiens of iFixit, an online Apple parts retailer. Portelligent's Howard Curtis agrees: "They're plain vanilla." A standard Infineon Technologies processor supplies the EDGE wireless-data capabilities and supports the camera and the movie playback system. There's also a transceiver for quad-band GSM connectivity. Marvell's chip is accompanied by a Cambridge Silicon Radio chip that offers Bluetooth 2.0. Critics scorn the iPhone for not working with AT&T's 3G network, but Apple has said that incorporating 3G hardware would add heat and reduce battery life. Wiens says the real issue is that 3G "is practically nonexistent outside large cities." Still, he adds, Apple will need to address this issue if it wants to sell the iPhone in Europe.
NAND Flash MemoryThe iPhone comes in two models, the only difference being storage capacity: one has four gigabytes, the other eight. Both use flash memory chips from Samsung that are "very, very similar to, if not the same as, the ones in iPods," says Kyle Wiens.
Move slider to take apart the iPhone and see its parts. Credit: Alastair Halliday
CPU The phone's brain is a custom-for-Apple CPU built by Samsung and based on a 32-bit, 620-megahertz core from ARM, which makes dedicated systems for use in cars, handheld games, smart cards, and other applications where power is at a premium. Howard Curtis says that working with ARM, a company prominent in the "embedded" market, could be significant for Apple. "OS X is now in the embedded space," he says, even as Microsoft keeps trying to build a desirable version of Windows for the same market.
BatteryThough the iPhone's lithium-ion battery is nothing new technically--"it's just like the battery in an iPod, but big, very big," says Wiens--it has gotten a lot of attention. That's because unlike the batteries in other cell phones, the iPhone's is soldered on and not (easily) replaceable by the user. (Apple will change a dead battery for $79 plus shipping.) At least one consumer has filed suit against Apple for its battery policy. Apple executives say that even after 400 complete depletion-and-recharge cycles, the battery will retain 80 percent of its charge capacity, which should be good for well over six hours of talk time.
Multitouch DisplayApple has had problems with the plastic screens on its iPods, which tend to show scratches, but the iPhone's screen is made of optical-quality glass. That's all the more critical because the screen is the interface. Instead of buttons or a keyboard, the iPhone uses a combination of new software and a unique multitouch screen manufactured by the German company Balda. Users tap "soft" buttons directly on the screen and zoom in or out of images or Web pages with two-fingered gestures (zoom out is a pinch, zoom in is a spread). This new control scheme abandons the WiMP (window, icon, menu, pointer) system that has dominated graphical interfaces on computers for decades.
AccelerometersLike Nintendo's Wii game console (see Hack, July/August 2007), the iPhone uses miniaturized accelerometers that measure its movement. These sensors detect whether the user is holding the iPhone in its "portrait" or "landscape" orientation; the operating system rotates the display accordingly.

The Rise of the Netjockey

2007-08-26T20:39:00.000-07:00

New software lets anyone create live talk shows for the Internet.
By Erica Naone

Live on camera: An Operator 11 netjockey, above, hosts his show from his home computer. Audience members can be guests on the show, or participate in the accompanying chat. This particular host decided to blur his face with a video effects filter.

Credit: Operator 11

Now anyone can become the host of a live internet talk show with software from the Hollywood-based startup company Operator 11. Using a home computer fitted with a webcam and headset, hosts, called netjockeys, use Operator 11's web software to produce, mix, and broadcast shows. In a new twist on the online video model, netjockeys can patch in live video of audience members, who thus become guest stars on the show without having to share a studio with the host. The software further encourages social interaction by running a chat room in conjunction with each show, where people can make comments without appearing on camera.
Operator 11 CEO Josh Harris says he sees the company as a video version of MySpace. While some shows have themes -- comedy, music and video games are popular subjects -- people are primarily using it for video chat. (Operator 11 does host some off-color chats, but Harris says all shows are monitored for content the company deems inappropriate.) On a particularly busy night this month, 130 shows were created.
The band Killola, for example, uses its Operator 11 shows to stay in touch with fans, sometimes hosting shows from their laptops while on the road. "We've been doing ... chats for a while," drummer Dan Grody says, "but never had this kind of platform to use." Fans can watch the shows live via the Operator 11 Web site or the band's MySpace page, and can appear in them if they have Operator 11 accounts.
Though the site's platform puts a lot of control in the hands of the users, Harris says this is currently a blessing and a curse. "We're asking too much of the audience at this point," he says. "...You've got to have the webcam, the right computer, the will to do it, and the ability to get over a little bit of a hump in using web software." Would-be users have to learn, for example, how to use the Operator 11 interface to mix feeds from different participants. Though project manager Guillermo Platas has been streamlining and improving the user interface, he says it's still difficult at first for most newcomers. Harris says users typically start by watching shows and participating in chat, before becoming full-fledged producers. "On the third day," he says, "you can see they've discovered lighting, makeup, and hair, and have figured out how to produce their own shows."
The software is still in the early stages of development and kinks still need to be worked out -- both for users learning to operate the system and for the technology. Many producers -- even those who work for the company -- still have trouble finding the right audio levels, for example, and there are sometimes slight delays between feeds. There can also be a wide range of video quality during a single show, since the Operator 11 software adjusts the quality of the video feed from one participant to another depending on the speed of their Internet connection. Platas says another challenge will be scalability: All the switching is handled on the server side, and, with increased participation, the load could get heavy.
"To do this right, you want adequate capacity and adequate quality of service," says Jon Peha, a professor in the department of electrical and computer engineering at Carnegie Mellon University. Interactive video is more demanding than other forms of streaming media, he says. Good video requires a much higher data rate than streaming audio, and is less tolerant of data loss. Unlike video sites such as YouTube, which download a video before showing it, Operator 11's model can't tolerate significant delays without destroying the flow of a show.
The company, however, seems committed to overcoming all the potential difficulties. In addition to addressing the technical issues, they are working on producing sample shows to act as guides for fledgling producers.
Meanwhile, Platas says, the company plans to release an updated version of the Operator 11 player and studio applications within the next few weeks. Harris hopes that, eventually, targeted advertising will make the site profitable.

Source: http://www.technologyreview.com

Rewritable Holographic Memory

2007-08-26T20:35:00.000-07:00

A genetically engineered microbial protein could mean better data storage.
By Amitabh Avasthi
By using lasers to etch data onto microbial proteins, researchers at the University of Connecticut may have demonstrated a way to produce rewritable holographic memory. Holographic memory stores data in three dimensions instead of two and could make data retrieval hundreds of times faster. The first holographic-memory systems have recently come to market, but they do not yet feature discs rewritable in real time.
Researchers at the University of Connecticut, Storrs, led by Jeffrey Stuart, head of the Nanobionics Research Center at the university's Institute of Materials Science, based their holographic storage system on reengineered versions of proteins produced by bacteria-like organisms commonly found in salt marshes. Simply shining blue light on the proteins erases any data stored in them.
The technology exploits an evolutionary adaptation of the microbe Halobacterium salinarum, which produces a light-sensitive membrane protein when concentrations of oxygen get too low. The protein, known as bacteriorhodopsin, helps the organism convert sunlight into energy. After the protein absorbs light, it cycles through a series of chemical states, releases a proton, and finally resets itself.
When the protein is in some of these states, its ability to absorb light allows it to form holograms. In the natural environment, each of the states lasts only briefly: the whole cycle takes just 10 to 20 milliseconds. But prior research has shown that shining red light on the protein as it nears the end of its chemical cycle can force it into a useful state--known as the "Q state"--that can last for years.
The problem is that the Q state is difficult to produce in the naturally occurring protein. So molecular biologists at UConn, led by Robert Birge of the chemistry department, are genetically manipulating Halobacterium salinarum so that it can produce a protein that enters the Q state more easily.
To serve as part of a holographic system, the protein is suspended in a polymer gel. A green laser beam is split in two, and one beam is encoded with data. The beams are then recombined in the gel, imprinting the proteins with an interference pattern that stores the data. To read the data, the system sends a single, lower-power, red laser beam back through the interference pattern. A blue laser erases the data.
Tim Harvey, CEO of Starzent, a Fairfax, VA, company that is funded by the U.S. Defense Advanced Research Projects Agency and is developing a miniature holographic data storage drive, says "Protein-based holographic media has the potential for low-cost removable media rewritable up to 10 million times." The protein is extremely robust, he adds, and if the researchers find the right genetic variant, current advances in biotechnology could help quickly produce large amounts of the protein at a low cost.
Holographic storage devices in general, Harvey notes, could bridge a growing gap between the capacity of storage devices and the speed with which they access data. As an example, he points out that transferring a 30-gigabyte file comprising a full-length high-definition movie to a computer's hard drive may take 30 to 45 minutes using current technology. Holographic devices have the potential to reduce that time to less than 10 seconds.
Among the people interested in the new development is Liz Murphy, vice president of marketing at InPhase Technologies in Longmont, CO, which has demonstrated a holographic device with a storage density of 500 gigabytes per square inch and has several products in the pipeline. "At least one potential advantage is that it is erasable and rewritable, which is rare among currently available media," Murphy says of the UConn researchers' device. "However, a drawback is that recording is in the red, and blue light is used to erase the recordings."
That's a limitation because "storage density typically increases with shorter wavelengths," she notes, pointing to the progression from CD to Blue-ray/HD-DVD technology. "So limiting use of the bacterial media to red wavelengths will make it less attractive to use for high-density data-storage applications."
Source: http://www.technologyreview.com/

Searching for Humans

2007-08-25T23:32:00.000-07:00

Various websites are trying to make it easier to find friends and colleagues online.
By Erica Naone
Jaideep Singh, cofounder of the new people-search engine Spock, says he wants to build a profile for every person in the world. To do this, he plans to combine the power of search algorithms with online social networks.
Singh says he got the idea for Spock while looking for people with specific areas of expertise among his contacts in Microsoft Outlook. Although he has two or three thousand people listed, he could only find people he was already thinking about.
Spock is designed to solve that problem by allowing users to search for tags--such as "saxophonist" or "venture capitalist"--and then view a list of people associated with those tags. Singh could have manually entered tags for each of his contacts into Microsoft Outlook, but capturing every interest of each particular individual would be time-consuming. Spock uses a combination of human and machine intelligence to automatically come up with the tags: search algorithms identify possible tags, and users can vote on their relevance or add new tags. Registered users can add private tags to another person's profile to organize their contacts based on information that they don't want to share. For example, a contentious associate might be privately labeled as such.
The social-network component of the website introduces an element of crowd commentary into the search process. George W. Bush is tagged "miserable failure," with a vote of 87 to 31 in favor of the tag's relevance as of this writing. Users aren't allowed to vote anonymously, and the tag links to the profiles of people who voted.
Singh hopes social networks will also help with one of the main problems in people search: teaching the system to recognize that two separate entries refer to a single person--a problem called entity resolution. For example, a single person might have a MySpace page, a Linked In profile, and a write-up on a company website. Steven Whang, an entity-resolution researcher at Stanford University, says that there are several aspects to the problem: getting the system to compare two entries and decide whether they are related, merging related entries without repetition, and comparing information from a myriad of possible sources online. Finally, Whang says, there is a risk of merging two entries that should not be merged, as in the case of a name like Robin, which is used by both men and women.
Many of the people-search engines try to get around these problems by encouraging people to claim and manage their own profiles, although Whang notes that this is a labor-intensive approach. Although there are many sites where people could claim their profiles, Singh says he thinks one engine will eventually dominate, and people will make the effort to claim profiles there. Bryan Burdick, chief operating officer of the business-search site Zoominfo, says that 10,000 people a week claim their profiles on Zoom, in spite of having to provide their credit-card numbers to do so.
Singh has also introduced the Spock Challenge, a competition to design a better entity-resolution algorithm. He says that 1,400 researchers have already downloaded the data set, and they will compete for a $50,000 prize, which will be awarded in November.
But although Spock and Zoominfo both stress the importance of being able to search by job title or other keywords, Michael Tanne, CEO of people-search engine Wink, says that isn't the most common need in people search. "That's not how 90 percent of searches are done," he says. "When you search for the iPhone, you want to see what's out there about the iPhone. But when you search for a person, you have a specific result in mind." While his site does allow users to search by tags, Tanne says that the tags are more commonly used to narrow down a search. Wink is able to search by variables such as location with more focus than the simple word recognition Google uses, Tanne says. For example, he notes, Wink would recognize that Framingham is close to Boston, and it would include both when a user enters "Boston" as a search term. (A spokesperson for Google says the search-engine giant currently has no plans to develop special features to improve people search.)
Singh says that Spock has indexed more than 100 million profiles so far--a reasonable start on the way to indexing every person in the world. But some people have raised privacy concerns. The people-search engines spider business sites and public Linked In profiles, but also social-networking sites such as MySpace. (Facebook information is kept private.) Business and personal information can appear on the same page, although Zoominfo attempts to index only the former. The sites' spokespeople all agree that the burden falls on the user to watch out for what's available online. "Whether you're managing it or not, you have a digital persona," Burdick says. Wink will remove profiles upon request, although not all people-search engines share that policy.
"The ability to see what you've put out there is an eye-opener to most people," Tanne says.

Credit: Spock
Crowd commentary: People-search engine Spock uses a combination of algorithms and user input to rank results and tag people with relevant keywords. The results can be quirky, as above: a search for "saxophonist" returns Bill Clinton as the top result, above jazz giants John Coltrane and Charlie Parker.

Talk to the Phone

2007-08-25T23:26:00.000-07:00

Speech-recognition software from Vlingo could make the mobile Web easier to use.
By David Talbot

Voice-recognition correction: Using Vlingo’s voice-recognition interface, a user can speak a sentence into a cell phone, see that sentence (in this case the text message “Hey Andy how’s it going”) appear on a screen, and use simple editing tools to replace words that may have been misinterpreted by voice-recognition technology. The interface helps users avoid manual entry of text messages, search terms, and e-mails.

Credit: Vlingo

Mobile phones can do lots of things: search the Web, download music, send e‑mail. But the vast majority of the 233 million Americans who own them never use them for more than calls and short text messages. One reason is that other features often require users to enter sentences or long search terms, a tedious task.
Speech-recognition interfaces could make such features easier to use. Vlingo, a startup in Cambridge, MA, is coming to market with a simple user interface that provides speech recognition across mobile-phone applications. "We are not developing the core speech-recognition engine," says cofounder Michael Phillips, a former MIT research scientist and founder of SpeechWorks, which developed call-center speech interfaces for clients including Amtrak. "We don't need to do that again." Instead, Vlingo takes speech, turns it into text, and provides a simple way to correct errors using the phone's navigation keys, helping the system "learn." The user's spoken words travel over a mobile Internet connection for analysis on Vlingo's server, sparing the phone the heavy computational work; the transcription appears less than two seconds later.
As a test, I asked the phone for "Schumann Piano Concerto." Vlingo came back quickly with "Sean Piano Concerto." When I hovered the cursor over the word "Sean," the system offered alternatives like "shine" and "sign." If one of them had been right, I could have clicked to insert it as a replacement. But since the right word didn't appear, I typed it in manually.
My correction upped the chances of better results in the future. I had taught the system that the next time I use a word that sounds like Schumann, "Schumann" should be one of my optional transcriptions. I also taught it that other people conducting music searches might use the word "Schumann"--so it might start popping up for them, too.
"Small platforms need speech, and search is a powerful way to find information," says James Glass, head of the spoken-language systems group at MIT's Computer Science and Artificial Intelligence Laboratory. "The combination of the two is very powerful," he says, adding that Vlingo is working at that frontier.
Vlingo wants mobile-phone carriers to bundle its interface with other offerings. "Carriers may be happy to give it away, because they will generate revenue as people actually use navigation systems or surf the Web," says CEO David Grannan.
Mazin Gilbert, executive director of natural-language processing at AT&T Labs in Florham Park, NJ, says others, including AT&T, are also developing speech interfaces for mobile phones; he thinks one problem will be "providing the right user experience in a cost-effective, scalable way." Vlingo thinks a simple, adaptable interface is one way to make growth easy.

Source: http://www.technologyreview.com

Cooling Chips with an Ion Breeze

2007-08-25T23:18:00.000-07:00

By using an electric charge to put molecules in motion, a new device can make a computer's fans more efficient.
By Prachi Patel-Predd

Cool breeze: Infrared images of a microchip’s surface show one of the two electrodes that generate a cooling breeze of ionized air in a new device developed at Purdue University. In the top image (red), fans keep the chip’s surface temperature at 60 ºC. In the bottom image (blue), activating the electrodes brings the temperature down to 35 ºC.

Credit: Birck Nanotechnology Center

Electrodes that send a flow of ionized air over the surface of a silicon chip could make the cooling fans in computers and laptops much more effective. Researchers at Purdue University and Intel found that a device that generates an ionic breeze keeps computer chips 25 ºC cooler than fans alone. By enabling the use of smaller fans, the device could lead to more-compact laptops.
As microchips get crowded with more and more components, today's cooling methods will no longer be adequate. Currently, heat is drawn away from chips by metal heat sinks--panels attached to arrays of fins or prongs that maximize heat-dissipating surface area. The fans in a computer cool the heat sinks and blow out the hot air. But air cooling "has been stretched to the limit in its capacity for heat removal," says Suresh Garimella, a mechanical-engineering professor at Purdue. And besides, fans can be bulky and noisy.
The new device is small and can be integrated directly into a computer chip. By placing it at specific "hot spots" on a chip, engineers could enhance the cooling fan's effectiveness in those areas. This could lead to smaller fans that work just as well as current fans, says Garimella, and thus to thinner, smaller laptops. The eventual goal is to develop cooling technologies for small notebooks and handheld computers, says Rajiv Mongia, an Intel research engineer who worked with the Purdue researchers on the new device.
Garimella and his colleagues built their experimental cooling system on a mock computer chip. The system consists of two electrodes--a stainless-steel wire that acts as the positively charged anode, and a copper tape that serves as the cathode--that are separated by a few millimeters.
Applying a voltage across the electrodes makes electrons in the air collide with oxygen and nitrogen molecules, stripping them of electrons and creating positively charged ions. The ions move toward the negatively charged cathode, dragging surrounding air molecules with them and creating a breeze. The researchers found that while a fan blowing over a heat sink cooled the surface of their chip to about 60 ºC, adding the ion breeze cooled it down to 35 ºC.
Garimella says that because the device uses strips of metal as electrodes, as opposed to sharper tips, the ion breeze sweeps a larger portion of the chip--although it does not generate enough air pressure to cool the chip without the aid of a fan.
The ion breeze faces stiff competition from other experimental chip-cooling techniques. Computer makers have recently started to explore liquid cooling, in which a pump pushes water or another liquid through pipes. (Apple's Mac Pro computers use this system.) But most liquid-cooling systems are complicated and increase manufacturing costs; the Purdue device could provide a cheaper alternative. "Our invention allows us to extend the performance of air cooling without having to switch to more aggressive and expensive methods such as liquid cooling," Garimella says. "At the same time, we do not add any extra volume."
A lower-volume approach to liquid cooling, however, may be forthcoming from Cooligy, based in Mountain View, CA. The company is developing a microchannel-based cooling technology licensed from Stanford University. The technology is a smaller, on-chip version of the pump-and-pipe method of circulating liquids. In Cooligy's device, cooling liquid circulates through tiny channels carved into a silicon layer that sits on top of a computer chip.
Girish Upadhya, director of applications engineering at Cooligy, has cautious praise for ion-breeze cooling, which he calls "a unique approach which may have specific applications in spot cooling." But he suspects that the Purdue device could prove difficult to incorporate into computer chips. "The hard part is to come up with a specific product using such an approach," Upadhya says.
Intel, which collaborated with the Purdue researchers, is keeping its options open. The company has also worked on a similar ion-pump approach with researchers at the University of Washington, in Seattle. (See "Tiny Pump Cools Chips.")
But Garimella is confident that the Purdue device will yield practical applications. First, however, the researchers will have to make it smaller and more rugged. "The device is at the millimeter scale, and we are working on reducing it to the scale of tens of micrometers," Garimella says. A smaller device, he says, can achieve the same cooling effect with lower voltages. And that, he adds, "would make the technology commercially viable."

Source: http://www.technologyreview.com/

Two-Sided Touch Screen

2007-08-25T23:10:00.000-07:00

A pseudo-transparent screen from Microsoft and Mitsubishi lets people enter data from both sides of a handheld device.

By Kate Greene

Transparent touch: Top: An illustration of a future multisurface, multitouch device. Bottom: A portable-device application that rotates, translates, and zooms in on a digital map. Superimposed on the map is an image of the user’s fingers, which are touching the back of the device. Credit: Microsoft

Researchers at Microsoft and Mitsubishi are developing a new touch-screen system that lets people type text, click hyperlinks, and navigate maps from both the front and back of a portable device. A semitransparent image of the fingers touching the back of the device is superimposed on the front so that users can see what they're touching.
Multitouch screens, popularized by gadgets such as PDAs and Apple's iPhone, are proving to be more versatile input devices than keypads. But the more people touch their screens, says Patrick Baudisch, a Microsoft researcher involved in the touch-screen project, the more content they cover up. "Touch has certain promise but certain problems," he says. "The smaller the touch screen gets, the bigger your fingers are in proportion ... Multitouch multiplies the promise and multiplies the problems. You can have a whole hand over your PDA screen, and that's a no go."
The current prototype, which illustrates a concept that the researchers call LucidTouch, is "hacked together" from existing products, says Daniel Wigdor, a researcher at Mitsubishi Electric Research Lab and a PhD candidate at the University of Toronto. The team started with a seven-inch, commercial, single-input touch screen. To the back of the screen, they glued a touch pad capable of detecting multiple inputs. "This allowed us to have a screen on the front and a gesture pad [on the back] that could have multiple points," says Wigdor. "But what that didn't give us was the ability to see the hands." So, he says, the researchers added a boom with a Web camera to the back of the gadget.
The image from the Web camera and the touch information from the gesture pad are processed by software running on a desktop computer, to which the prototype is connected. The software subtracts the background from the image of the hands, Wigdor explains, and flips it around so that the superimposed image is in the same position as the user's hands. Additionally, pointers are added to the fingers so that a user can precisely select targets on the touch pad that might be smaller than her finger. In October, a paper describing the research will be presented at the User Interface Software and Technology symposium in Rhode Island.
Admittedly, this prototype has several limitations. Most glaringly, it's impractical to attach a boom and camera to the back of a handheld device. In their paper, the researchers suggest a number of different approaches for more-compact LucidTouch prototypes. The gesture pad on the back could actually provide an image of the user's fingers as well as touch information, explains Wigdor. The pad uses an array of capacitors, devices that store electrical charge. Fingers create a tiny electrical field that changes the capacitance of the array, depending on their distance from it. This distance can be tuned, says Wigdor, so that the pad can register the entire finger, and not just the fingertip touching it. Another approach, he says, would be to use an array of tiny, single-pixel light sensors that could map fingers' locations. Or the device could use an array of flashing, infrared-light-emitting diodes; sensors would then detect the light's reflection off of a hand, Wigdor explains.
As touch screens shrink, says Scott Klemmer, a professor of computer science at Stanford University, one of the biggest problems users face is inadvertently covering up content with their fingers. LucidTouch, he says, "distinguishes itself in two ways: first, it provides better feedback about where you are ... and the other distinction is that it's multitouch."
Even with their prototype's cumbersome design, the researchers were able to write applications for it and gather user responses from a small group. Depending on the application, users found that touching the back of the screen could be useful. For instance, most preferred to type on a Qwerty keypad using the front of the screen. But when the keypad was split down the middle, and one half was placed vertically along each side of the screen, most preferred to type on the back of the device. Half of the participants preferred using the back of the device for tasks such as dragging objects and navigating maps. The users were also divided on whether the superimposed images of their fingers were helpful. Two-thirds of the participants preferred the superimposed images when using the keyboard and dragging objects, and half preferred them while using the map.
These results suggest that a user's preference for LucidTouch and pseudo-transparency depends on the application. Baudisch suspects that one of the first places that this technology could appear is in portable gaming, where specific games could be written for the technology. But importantly, it could enable people to start thinking differently about the potential of multitouch screens on handhelds.
"I think--zooming out for a moment--what's really exciting about this time is that for so many years, we've seen the dominance of the mouse," says Stanford's Klemmer. "I think that hegemonic situation is now over. What this points to for me is the idea that we're going to see this increased diversity of devices that adapt to different situations."

Source : http://www.technologyreview.com

A New Design for Computer Chips

2007-08-25T11:18:00.000-07:00

An MIT spinoff introduces the first commercial chip with a mesh architecture.

By Kate Greene

Multicore mesh: This chip, which measures about 40 millimeters square, contains 64 processors--or “cores”--connected to each other in a mesh network, a new chip architecture. The processor is currently shipping to companies that make videoconferencing technology and network routers.
Credit: Tilera

Today, MIT spinoff Tilera announced that it's shipping a computer chip with 64 separate processors whose design differs drastically from that of the chips found in today's computers. The new chip, called Tile64, avoids some of the speed bottlenecks inherent in today's chip architecture, and it can operate at much lower power, says Anant Agarwal, founder and chief technology officer of Tilera, based in Santa Clara, CA. Initially, Tile64 will be used in video applications such as videoconferencing systems, and in network hardware that monitors traffic to reduce e-mail spam and viruses.

Chips with multiple processing units, or "cores," are nothing new. But by allowing the cores to communicate directly with each other, Tilera has addressed a widespread concern about the viability of adding more cores to microprocessors. "Every processor in the market today is a multicore," says Agarwal. "The hope of the industry is to double the number of cores every 18 months. My prediction is, by 2014, we will have 1,000-core architectures. But the problem is, [current] architectures don't scale."

In existing multicore chips, each core communicates with the others via a set of wires called a bus. Performance doesn't necessarily suffer when two or four cores share a bus, but when 16 or more cores try to use it simultaneously, data can get backed up. Agarwal explains that Tilera's chip has no central bus. Instead, each core is connected to all the others. Also on each core is a full-featured processor, which can run an operating system, and memory caches, which hold data that needs to be quickly accessed.

In effect, the Tile64 has a mesh structure that's similar to that of the Internet, a network in which there are many decentralized nodes. One reason the Internet is able to pass around data so quickly is that packets of information are sent through a vast network and can avoid traffic jams. If everyone's e-mail had to go through a central server, there would undoubtedly be delays. Tilera's microprocessor, says Agarwal, "is very much like the Internet on a chip." And like the Internet, Tilera's chip can be scaled up gracefully; it doesn't need to be redesigned each time new cores are added.

The idea of using mesh architecture for multicore chips has been explored for at least a decade, in research labs at MIT, Stanford, and the University of Texas, Austin. And recently, Intel announced a prototype 80-core chip based on a mesh. But Tilera is the first company to offer a product that uses the new architecture.

"Having a lot of cores is good, but they must be able to communicate with each other at high data rates," says Jerry Bautista, codirector of Intel's terascale-computing research program. "There are advantages to using a mesh ... You can deal with traffic jams pretty easily." Bautista says that Intel researchers are trying to find the best way to implement mesh architectures--among other experimental designs--in future chips. But he also cautions that making massively multicore systems work efficiently isn't as simple as redesigning the hardware.

"We believe that to really get the most use out of these many-core systems, there's going to be quite a significant modification to the way people program today," Bautista says. The cores can handle many different instructions at once, he says, and software engineers will have to learn new programming techniques to take full advantage of the added computational capacity.

Tilera's Agarwal says that his company has addressed that concern by providing a software environment that helps customers gradually upgrade, debug, and optimize their applications to work on the 64-core system--even applications designed to run on a single core.

The company's technology is being presented this week at the Hot Chips symposium at Stanford, in Palo Alto. Nathan Brookwood, founder of Insight64, an analysis firm, says that many people at the conference are excited about Tilera's work, mainly because it could have immediate applications, such as expanding the capacity of videoconferencing systems and analyzing network traffic in routers. "I think they have a potential winner here," says Brookwood.

Intel's Bautista says the marketplace may be ready for a chip with more computing power, but it would need to be low power and easily programmed. He says that Intel will keep an eye on Tilera, as it does on many startups that are first to market with new technologies, to see how customers respond and which aspects of the technology could be improved. "We use companies like this to help us test the waters," he says.

Source: www.technologyreview.com