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Stanford graduate students solve the silent Prius problem

2355512640_5a354fc579.jpgI live in a Prius neighborhood. In the short two-block walk to the local elementary school this morning, I counted six. In general, I think thatâ''s a good thing.

I also live in a â''playborhoodâ'', thatâ''s a new word for a retro idea: a neighborhood in which kids play unorganized pickup games outside, sometimes (OK, a lot of times) in the street. In general, I also think this is a good thing.

But combine these two trends, and, in the eyes of a worried mom, youâ''ve got an accident waiting to happen. The kids are pretty good about listening for a car turning onto our street and scoot to the sidewalks. But a Prius operating in electric mode is virtually silent.

Besides being a threat to kids playing in the street, the silent car is a nightmare for blind pedestrians. Concern about silent car dangers led to the introduction of the so-called â''Bell the Hybridâ'' Act, a.k.a. the Pedestrian Safety Act of 2008, HR 5734, introduced in April which, if it passes, would direct the Secretary of Transportation to establish a motor vehicle standard that would alert pedestrians to a carâ''s approach.

That wouldnâ''t be hard; there are a number of ways one could do this; heck, kids have

been clipping playing cards to make their bicycles buzz for generations. One suggestion is a radio transmitter that sends a signal to some sort of buzzer carried by the blind. Thatâ''s unlikely to fix the kid-in-the-street hazard, however.

Another approach is already in prototype and going on the road this summer to conferences aimed variously at the auto industry or the vision impaired. Called the PANDA system, or â''Pedestrian Awareness Noiseâ''emitting Device and Application,â'' it comes from Enhanced Vehicle Acoustics, a corporate name for two Stanford University graduate students, Bryan Bai, an electrical engineering graduate student, and Everett Meyer, medical student. The PANDA system uses small speakers installed in the front wheel wells and under the back fender; a little box (the prototype sits in front of the gear shift) sends the sound to the speakers. The system designers say the noise isnâ''t audible from inside the car; from the outside, itâ''s just a little quieter than a normal combustion engine. You can hear it for yourself here or below.

Photo credit: auntjojo

High-rate, Directed Assembly of Nanostructures Promises Big Changes in Electronics

One of the problems plaguing the application of nanotechnology into electronics is that it has proven quite difficult to develop a reliable process for high-rate, directed assembly of nanostructures. Processes like ultra-violet nanoimprint lithography have been restricted to very low rate processes.

Now, researchers at the National Science Foundation's Nanoscale Science and Engineering Center for High-rate Nanomanufacturing (CHN) at Northeastern Universityâ''with partners UMass Lowell and University of New Hampshire--are claiming they have developed a process that enables directed assembly of single-walled carbon nanotube (SWNT) networks to create a circuit template that can be transferred from one substrate to another.

The researchers, led by Ahmed Busnaina, are expecting that this approach will make possible the mass production of reliable nanoscale structures, ultimately leading to a host of applications in consumer electronics.

While it appears the research was specifically targeted for industry, I cannot see if the CHN had any industrial partners for this specific project. However, they do note some industrial partners for the overall center. No specific journal was mentioned for where they published their findings, other than the Small Time article I linked to above.

Tribute to computing pioneer Jim Gray to be webcast Saturday

jimgray.gif Jim Gray, one of computingâ''s greats, will be honored by his colleagues and family this Saturday morning (9 a.m. PDT) at a ceremony at the University of California at Berkeleyâ''s Zellerbach Hall and in a live webcast here. Gray, winner of the Association for Computing Machineryâ''s Turing Award in 1998 for his contributions to database and transaction processing, disappeared at sea in January of 2007. His disappearance, during a short solo sailing trip in good weather, remains a mystery, in spite of an exhaustive high tech search, in which countless volunteers examined thousands of satellite images looking for clues. The long hunt ended in May 2007.

Gray earned the first PhD in computer science ever awarded by the Univeristy of California at Berkeley back in 1969; he worked at Bell Labs, IBM, Tandem Computers, Digital Equipment Corp., and Microsoft, convincing the Redmond, Wash., giant to open a research center in San Francisco so he wouldnâ''t have to move. Researchers credit his work with enabling ATMs, ecommerce, online ticketing, and other database intensive services we take for granted today. In recent years, Gray focused on the effort to create a world-wide telescope and in building a digital library of the worldâ''s scientific literature. Read a recent interview in IEEE Distributed Systems Online here.

At the tribute, sponsored by the IEEE Computer Society, the ACM, and UC Berkeley, Mike Olson, vice president of embedded technologies at Oracle, will talk about the search effort, computer science professor Mike Harrison will discuss Grayâ''s impact on Berkeley, and David Vaskevitch and Rich Rashid, Microsoft senior vice presidents, will describe Grayâ''s contributions to the computing industry.

Solar Squabble Amplified by Popular Podcast

Spectrum's April 2008 feature on growing dis-ease within the community of researchers developing plastic solar technology -- "Solar Cell Squabble" -- is itself featured today in a leading podcast on renewable energy. The story laid bare widespread concern over the possible mismeasurement of performance of the potentially cheap and flexible organic photovoltaics. An interview on the story behind the story tops the weekly Inside Renewable Energy podcast published by

Organic PV researchers concerned by the measurement controversy's impact on their field are organizing to keep the issue on the front burner. UCLA organic pv expert Yang Yang and Christoph Brabec, a senior scientist at organic PV developer Konarka Technologies, organized a session on "Accurate Measurement of the Efficiency of Organic Photovoltaic Devices" for the upcoming conference SPIE Optics + Photonics (see Session 5 under the Organic PV track). This annual meeting of the International Society for Optics and Photonics will take place August 10-14 in San Diego.

Yang estimates that the organic PV field has overstated performance by about 30% through inattentive handling of light sources with a different color balance from sunlight. He says testing very small cells has inflated results by another 20-40%. He says it's inevitable that, without change, the field's credibility will be burned. "We need to take care of this issue before it is too late," says Yang. "In fact, it is already late."

Nanowires Produce More Efficient Thin-Film, Polymer-based Photovoltaics

Last month I submitted a blog entry that suggested if there were a third generation of photovoltaics (first-generation solar cells (single-crystal silicon wafers) and second-generation solar cells (thin-film semiconductors)) using quantum dots that could reach or exceed the 32% Shockley-Queisser Limit than the economics of photovoltaics could improve and their adoption accelerated.

To add to this mix has been recent research at the University of California San Diego in which electrical engineers have added nanowires to polymer-based thin-film photovoltaics to create solar cells that increased the forward bias current by six to seven orders of magnitude as compared to their polymer-only control device.

The work was published in American Chemical Societyâ''s NanoLetters.

When one considers how much cheaper thin-film polymer photovoltaics are compared to single-crystal silicon wafers, and then factor in the possibility of thin-film polymer solar cells becoming orders of magnitude more efficient, things start to look pretty rosy.

But hold on, there remains some pretty fundamental problems, most notably that the polymers begin to degrade quite rapidly when exposed to air. However, the researchers point to work going on around the world to improve the properties of organic polymers that could overcome this problem.

In light of the recent series of entries here and here on this site regarding a potential â''Photovoltaics Mooreâ''s Lawâ'' based on ever decreasing price points as opposed to the ever increasing number of transistors per unit of a chip, and the strong reaction to them, it may be worth adding that we may not have to remain bound to the paradigm of silicon wafers and its incremental improvements.

Is Photovoltaic Moore Law Really on Track?

Last week, based on an IEEE photovoltaics conference that had just taken place in San Diego, I reported on some positive developments: a kind of Mooreâ''s law allegedly at work, a better outlook for first-generation silicon cells, and a growing expectation that solar electricity may be commercially competitive in some parts of the world by 2015. It appears that I misstated and overstated the case for a photovoltaic Mooreâ''s law, havingâ''Iâ''m most embarrassed to sayâ''misread one of my own previous blog entries.

I said last week that PV costs per watt had dropped from about $7 in 2004 to $4-5 in 2007, but â''Halâ'' pointed out in a comment posted May 22 that my previous blog in fact cited 2007 PV costs of $7.6 or $6.2 (depending on whose numbers you believe). That would be tantamount to a cost reduction of 15 percent at most, and perhaps none at allâ''not the 40 percent reduction I thought I had discerned, consistent with the â''photovoltaic Mooreâ''s lawâ'' that postulates a 20 percent reduction with every doubling of cumulative production capacity.

In recent years, total capacity has been doubling about every 18 months, but longer term the rate has been more like 30 months, according to John Benner of the National Renewable Energy Laboratory, who takes some credit for originating the PV Mooreâ''s law postulate. Benner says the three years from 2004 to 2007 were anomalous because of a run-up in silicon prices and, perhaps too, the deteriorating value of the dollar.

Even so, relative to wind, photovoltaic costs do indeed appear to have improved rather dramatically between 2004 and 2007, from 7:1 to 4:1 or 5:1, close to 40 percent. Thatâ''s significant, as distributed PV only needs to be about half as costly as central wind to be competitive. But PVâ''s better standing owes as much to an escalation in windâ''s costsâ''connected with booming global demand for turbines and the general run-up in power plant costs, most likelyâ''as to any cost reductions of its own.

The solar-wind comparison is a reminder that the photovoltaic Mooreâ''s law is subject to market forces in a way that the real Mooreâ''s law is not, as comments on my May 17 blog emphasized. Even the semiconductor Mooreâ''s law is of course not a law in the normal sense; itâ''s a prediction that happens to have been born out, so far, by reality. But it at least is stated strictly in terms of physical parameters (how many transistors per unit area of chip). The PV Moore law is stated in terms of costs, making it subject to extraneous market forces.

â''It used to be an axiom that solar power grew steadily cheaper as time passed,â'' The Economist magazine noted last April. â''After all, it had done so reliably for the previous 40 years.â'' But in the last years, Germanyâ''s extravagant solar subsidies have driven up global prices for silicon, from $25 per kilogram in 2003 to around $400/kg now. â''We didnâ''t have a silicon shortage, we had an over-stimulated market,â'' comments Benner.

Even if the consternation the higher silicon prices have aroused among solar boosters is somewhat misplacedâ''after all, just about every other energy cost is sky-rocketing tooâ''the situation has prompted arguments that solar subsidies should be eliminated in favor of R&D support.

Is there an optimal rate of PV growth? If we try to give the industry too much of a kick can that backfire, disrupting the learning curve thatâ''s supposed to yield â''grid parityâ'' by middle of the next decade? Should research and production incentives be targeted or technology-neutral, and what is the right mix? Who provides the better model, Germany or Japan? Those were just the questions under discussion at the San Diego PV Accelerator Forum, and which will continue to be discussed by all who have the future of solar electricity and renewable energy at heart.

Meanwhile, I apologize to my readers for having overly accentuated the positive. I hope I read your writing more meticulously than I sometimes reread my own.

The Long and Short of Carbon Nanotubesâ¿¿ Similarity to Asbestos

A recently published paper in Nature Nanotechnology submitted by researchers at Edinburgh University led by Ken Donaldson has provided evidence that some carbon nanotubesâ''specifically multi-walled carbon nanotubes (MWNT) that are longer than 20 µmâ''have the same pathogenic effects as asbestos.

Like asbestos, the MWNTâ''s toxicity is not due to their chemical composition but their physical characteristics, namely their length.

The pathogenic quality of both MWNTs of a certain length and asbestos occurs when the bodyâ''s phagocytes attempt to engulf the fiber, and when unable to get around the entire length of the fiber, the phagocytes try to kill the fiber with toxic products. The attempt fails to kill the fiber but succeeds in damaging the surrounding tissue.

If you donâ''t have a subscription to Nature, I suggest reading Richard Jones blog entry at Soft Machines, which gives a pretty thorough review of the findings and what it all means.

As Jones notes, â''not all carbon nanotubes are equal when it comes to their toxicity. Long nanotubes produce an asbestos-like response, while short nanotubes, and particulate graphene-like materials donâ''t produce this response.â''

Jones further emphasizes, â''the experiments do not say anything about issues of dose and exposure.â''

While Jones did not initially know what percentage of the carbon nanotubes on the market fit the description of those that were used in the tests, the International Council on Nanotechnology (ICON) provided a backgrounder that provides some information in this area.

The MWNTs that might fit this description, Jones notes, are integrated into a material matrix, which leaves the threats of exposure in two areas: workers who are working with the MWNTs before they are integrated into a material matrix and what happens in the life cycle of the products, especially after disposal.

Phoenix Landing on Mars Makes History

This time it all went perfectly. After a voyage of 422 million miles lasting 10 months, NASA's Phoenix Mars Lander came to a rest on a spot on the Martian Arctic yesterday at 7:38 pm EDST. The long-awaited journey's end had its handlers shouting in triumph, savoring the success of one of the most complicated interplanetary missions in history. The last time the U.S. space agency attempted to send a big exploration platform to an ice cap on the Red Planet, with the 1999 flight of the Mars Polar Lander, it ended in failure during the critical landing sequence, which astronautic engineers call the "seven minutes of terror" (see video below).

Those seven minutes, this time, rolled by with every item on the technical checklist kicking in nearly as programmed by scientists many months ago. A minor glitch caused the Phoenix's parachute to open seven seconds later than scheduled, sending the research craft several miles downrange of its target on a stretch of northern plains dubbed Green Valley by mission planners. Nonetheless, yesterday's operation resulted in a historic milestone in space exploration, the first successful mission to a Martian polar region, where subsurface ice is believed to exist.

Due to the great distance its radio signals had to travel, confirmation of touchdown did not reach Earth, at NASA's Goldstone Space Communications Station in California's Mojave Desert, for about 15 minutes, where the result was instantly relayed to the Jet Propulsion Laboratory, in Pasadena, Calif. The JPL team, in charge of the flight portion of the mission, immediately broke out in boisterous applause at the confirmation (see video below): "Touchdown signal detected."

Led by JPL Project Manager Barry Goldstein, the flight team shouted, "It's down, baby, it's down!"

The Phoenix's perilous descent saw it decelerating from some 12 000 miles per hour at the edge of the Martian atmosphere to about 5 mph as it approached the surface using eight pulsed retro-rockets to gently coast it to a landing. The US $420 million spacecraft then released its remaining helium fuel and, after waiting for dust to settle, began deploying its twin solar-power arrays.

"It was better than we could have imagined. Everything just worked like a charm," said Goldstein. "The hardest part is over," he added.

Photo: NASA

FLOATING TO MARS: A spectacular image captured by the Mars Reconnaissance Orbiter's HiRISE camera showed the Phoenix with its parachute deployed high above the polar plains.

About two hours after touchdown, according to an update from NASA last night, the Phoenix's cameras began to transmit the first images of the northern polar landing zone, including this colorized photo of the ground around the settled vehicle.

"We see the lack of rocks that we expected, we see the polygons that we saw from space, we don't see ice on the surface, but we think we will see it beneath the surface," said Peter Smith of the University of Arizona at Tucson, principal investigator for the Phoenix mission. "It looks great to me."

"Seeing these images after a successful landing reaffirmed the thorough work over the past five years by a great team," Goldstein commented yesterday (the 47th anniversary of Pres. John Kennedy's call to to send a man to the moon).

Now, the real work of interplanetary science begins for Phoenix: scooping the Martian "permafrost" soil for evidence of frozen water.

We'll continue to keep you posted on the progress of Phoenix. In the meantime, for more on the mission's background and implications, please review this account, "Martian Cliffhanger Resolved at Last", at MSNBC by our Spectrum Online contributor (and mentor) Jim Oberg.

It's the stuff history is made of.

Out of Africa: Ultralow power PCs

Africa's electricity shortages are getting the attention of some very clever desktop computer designers in San Francisco -- at an innnovative technology and development organization called Inveneo.

I first encountered Inveneo's marvelous low-power PC in a dusty, poor village in Rwanda, the country made infamous by the 1994 ethnic genocide and then famous by the Hollywood blockbuster film, "Hotel Rwanda.". Late one afternoon, I visited an Internet cafe -- a small shop where people pay about a dollar an hour to send emails and search the Web. Instead of a normal bulky, power-hungry computer, I found a small, simple and energy-efficient one.

Indeed, the electricity footprint of this PC was unbelievable small: a mere six to eight watts, many times less than a normal computer.

The power requirement is so low that a simple solar device, costing less than $500, can drive this computer for eight hours -- day after day.

More than a year passed before I met the talented people who devised this computer. The other day, I went to the offices of Inveneo, whose staff hang out in a scruffy building in the trendy but still-funky "South of Market" neighborhood. There I met Robert Marsh, Inveneo's engineering guru, and the group's charismatic chairwoman, Kristin Peterson.

In the 1970s, Marsh was a founding member of the legendary Homebrew Computing Club, a font of creativity for what became the PC industry in Silicon Valley. Marsh designed the Inveneo PC using off-the-shelf parts. they are cheaper of course. He chose an ultra-low-power AMD chip-set and a low-power flat-panel monitor. "I tested a ton of them," Marsh recalls, "until I got it right."

Inveneo sells the PC for $469. First released about a year ago, the computer is usually purchased by foreign donors, supporting one of the dozens of African partners that Inveneo works with to expand technology expertise in the region. To date, about one thousand of these PCs are being used in Africa.

"The benefits are various," says Peterson, who travels often to the region. "These computers work in areas where electricity is undependable, or maybe there is no electricity."

Even in African cities, "there is heat, dust and humidity," she adds. "These are punishing environments for computers."

By going against the grain of the computer industry -- where ample electricity is taken for granted -- Marsh was able to conceive of a novelty -- that makes perfect sense in the sub-Saharan.

Today, Inveneo's PCs are assembled in the U.S., so the obvious next challenge is to bring assembly closer to Africans. That will require more training and resources in the places using these computers. And that reminds Peterson of a central insight that animates her work in human development: "Technology alone isn't enough."

[For more about Inveneo, watch this clip from CNN]

Japan Experiences a Flight from Science

According to a recent article in The New York Times, Japan is running out of engineers and scientists.

After decades of eminence in the fields that made it a world leader in technology, Japan now finds itself worrying over its future, as its young people flock to professions in other areas. Japanese educators have even given the trend a name: rikei banare (or "flight from science").

By one estimate from the nation's ministry of internal affairs, there is a shortfall of almost half a million engineers available to Japan's industrial infrastructure.

Much like American youngsters, Japanese students increasingly are choosing career paths in more lucrative or glamorous sectors such as finance or the arts. The drop-off in those studying math, science, and engineering has become so severe, the Times reports, that Japanese industrial firms have begun advertising campaigns designed to make these pursuits "look sexy and cool."

More pragmatically perhaps, Japanese business planners have initiated programs to invite young engineers and scientists to their shores to fill in the looming gaps--as well as to send high-tech assignments overseas to where the talent pool is potentially deeper, such as India and Malaysia.

So far, these efforts have failed to turn the tide in terms of meeting the country's enormous future needs for brain power, according to the Times.

"Japan is sitting on a demographic time bomb," Kazuhiro Asakawa, a professor of business at Keio University, told the U.S. newspaper. "An explosion is going to take place. They see it coming, but no one is doing enough about it."

If it sounds like a familiar refrain to many in Western industrial nations, it's because Japan is hardly alone. The more prosperous a nation becomes, the more it tends to squander the very source of its own prosperity.


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