Sunday, July 26, 2009

Cheaper Geothermal

Fluid extracts more heat out of low-temperature wells.

By Tyler Hamilton


Researchers at Pacific Northwest National Laboratory in Richland, WA, say they've developed a superior type of heat-extracting fluid that could dramatically improve the economics of producing renewable power from low-temperature geothermal resources.

Tapping geothermal: A molecular representation of a nanomaterial developed at Pacific Northwest National Laboratory that can improve the efficiency of geothermal power plants.
Credit: PNNL

Lab fellow Pete McGrail says the liquid is used to absorb the heat from hot water that's been pumped from underground into a geothermal plant's heat exchanger. The liquid can potentially boost the rate of heat capture by 20 to 30 percent. Researchers engineered proprietary nanomaterials made up of metals linked by organic molecules. They found that adding the nanomaterials to a fluid such as hexane or pentane significantly enhanced the heat-trapping properties of the liquid.

"The hope here is that by improving the efficiency as much as we think we can, a project can become economic at much shallower depths," says McGrail. "You'd be able to deploy in what would now be considered marginal or uneconomic areas."

There's no shortage of geothermal energy under our feet. Drill deep enough and the heat is there. An MIT-led study from 2006 concluded that geothermal power systems have the potential to supply 100 gigawatts of power to the United States by 2050, but only if new drilling and rock-fracturing technologies and advanced plant designs emerge that could lower development costs.

Improved technologies are required because most economical geothermal plants today generate electricity by using steam or hot water directly from naturally formed high-temperature reservoirs, such as the Geysers field in California. The wells are relatively shallow, the water is 360 degrees Fahrenheit or hotter, and the rock is porous enough to sufficiently circulate water. Tapping geothermal resources in less-ideal locations requires drilling deeper and forcing fractures in rock, both of which add immense cost. It also means making the most of lower-temperature heat resources, which is accomplished using binary-cycle plants that extract and repurpose the heat from underground hot water rather than using the hot water directly to spin a turbine.

In these plants, water pumped into an injection well absorbs heat from hot rock and is pumped back up through a separate extraction well at temperatures ranging from 150 degrees Fahrenheit to 300 degrees Fahrenheit. The hot water is then passed through a heat exchanger, along with a fluid with a low boiling point. This fluid, which flows in its own closed loop within the plant, absorbs the heat from the water and flashes into vapor under high pressure. The vapor passes through a turbine, generating power, and is then condensed and recycled back through the loop.

McGrail and his research team stumbled on a way to boost the energy-conversion rate as the two loops pass through a heat exchanger. Initially, they had developed proprietary materials for another project to improve the capture of carbon dioxide emitted from a fossil-fuel plant. They realized that the materials had remarkable thermodynamic qualities when added to an organic fluid. The new fluid has the potential to capture up to 30 percent more heat from a closed water loop, and, because of its rapid expansion and contraction capabilities, it can achieve higher pressures for driving the turbine.

"It's one of those moments in the lab where you look at the data and say, 'Wow!'" says McGrail. His group has received a $1.2 million grant from the Department of Energy's geothermal technologies program to build a benchtop prototype that shows the properties of the fluid in action.

"Hopefully we'll get a test loop system together by the end of the year. We'll put together a complete working unit with heat exchanger, compressor, pumps, and a turbine system so we can see the whole process working," he says.

The lion's share of the cost of geothermal is in drilling and preparing production wells, says Susan Petty, chief technology officer of Seattle-based AltaRock Energy, a developer of enhanced geothermal systems. "If you're going to get a 20 percent or higher improvement in efficiency, that's 20 percent less well," she says. "That is really, really significant."

There are potential showstoppers, however. Ron DiPippo, professor emeritus of mechanical engineering at the University of Massachusetts Dartmouth and a coauthor of the MIT report, warns that the vaporized fluid must pass through the turbine without affecting performance. "You have to really view these things skeptically and do a careful analysis of the properties of these fluids," he says. "You may have a gain on one side and a sacrifice on the other end."

Testing how the nanomaterials pass through the turbine will be a priority once the prototype is developed, says McGrail. "We don't know if it will be an issue yet."


http://www.technologyreview.com/energy/23065/

Big Oil Turns to Algae

ExxonMobil invests $300 million in Synthetic Genomics to develop algae biofuel.

By David Ewing Duncan


Two of Craig Venter's recent passions have been combing the Earth for microbes and other minute critters that reveal the diversity of life, and creating and redesigning life itself through synthetic biology.

Growing green: Synthetic Genomics and ExxonMobil are collaborating on the development of photosynthetic algae to make biofuels.
Credit: Synthetic Genomics

Never thinking small, Venter also has not been shy about blending research and commerce in his quest to finance and further his projects. In the 1990s he created Celera Genomics with over $1 billion in financing to compete with the public project to sequence the human genome.

There comes a point, he once told me, when projects need the king-size resources available in the private sector to scale up and implement. In this case, the goal is to produce a viable alternative fuel to petroleum and--just possibly, he insists--to reduce the fresh carbon spewed in the air when petroleum is burned.

Last week, ExxonMobil announced a commitment to invest $300 million over five to six years in Synthetic Genomics, which Venter founded and now leads as CEO, and to spend an additional $300 million on a complementary internal algae program.

The push is to take advantage of algae's ability to efficiently transform sunlight into lipids that can be relatively easily converted into diesel, gasoline, and possibly even advanced hydrocarbons used to manufacture plastics, chemicals, and other products.

By the barrel, algae fuel provides three to four units of energy for every unit used to make it--a ratio that approaches petroleum's 5-to-1 level of efficiency. The ratio for making ethanol from corn is a mere 1.2 to 1, according to some studies. Even making ethanol from cellulosic plants like switchgrass, researchers can achieve only a 2.5 to 1 ratio.

Venter's company has been developing strains of bioengineered algae that ramp up the output of lipids and can in some cases produce hydrocarbons directly. However, Venter and Emil Jacobs, senior vice president for R&D at ExxonMobil Research and Engineering, both emphasize that their companies will collaborate to investigate any viable option to push algae into the big time of energy sources.

Since research in algae fuels began in the 1970s at the Department of Energy--as part of President Jimmy Carter's efforts to develop alternative fuels after the oil shocks of that era--several methods have emerged.

First is an open-pond system that grows algae out in the sun. Another is a closed, sunless system that feeds carbon from feed stock such as sugarcane to algae plants in fermentation tanks. A third type is a closed-system bioreactor that uses sunlight.

Synthetic Genomics has favored processes that use sunlight. They also tend toward bioengineered plants, but they will experiment as well with naturally occurring algae that optimize output and other parameters. Researchers have searched all over the planet for candidate species, said Jacobs.

So far, converting algae to fuel has been tried only on a small scale, and whatever process is used will require building massive new infrastructure for water management, feedstock supplies, nutrients, cultivation, and transportation, even if algae oil can be refined at existing facilities.

Algae can be grown on land unsuitable for food crops, but no one yet knows how to optimally produce the vast quantities of algae necessary to supply even a small fraction of the world's appetite for fuel. A study in 2004 at the University of New Hampshire concluded that 30 million acres--a space the size of South Carolina--would be required to grow enough algae to satisfy U.S. transportation needs.

ExxonMobil's investment comes after a mini-boomlet last year of investment in algae as oil prices skyrocketed. Other oil companies such as Chevron, Royal Dutch Shell, and BP have invested in algae. Last year, Bill Gates's Cascade Investment fund invested a reported $50 million in Sapphire Energy, based in San Diego.

The investments slowed down considerably after oil prices fell, though the current collaboration suggests that more investments will be coming. The Department of Energy has just announced that it will invest $85 million in stimulus money on "advanced" biofuels that can be derived from algae and other feedstocks.

If successful, the collaboration between Venter's company and ExxonMobil could mean an investment of billions of dollars, said Jacobs--numbers Craig Venter hasn't seen in a commercial enterprise since the headiest days of Celera back in the late 1990s.

That venture produced exceptional science, but was less successful as a business. Time will tell if this latest high-risk gambit into a new and promising, but untried, technology will create a revolution in business and science or turn out to be just so much pond scum.


http://www.technologyreview.com/energy/23039/

A Superlens That Assembles Itself

Easily made nanolenses can perform superhigh-resolution lithography and imaging.

By Katherine Bourzac


Korean researchers have created nanoscale lenses with superhigh resolution using a novel self-assembly method. So far, they've demonstrated that the tiny lenses can be used for ultraviolet lithography, for imaging objects too tiny for conventional lenses, and for capturing individual photons from a light-emitting nanostructure called a quantum dot.

Self-assembly line: The spherical nanolenses shown in this electron microscope image have separated from the crystalline nanotubes underneath them. The structures spontaneously form when a solution of cup-shaped organic molecules is allowed to evaporate.
Credit: Nature

The limits on the resolution of both light microscopes and the photolithographic instruments used by the semiconductor industry are a consequence of light's fundamental properties. Because of the way light scatters, or diffracts, even a perfect lens cannot distinguish two objects that are closer together than half the wavelength of the light used to image them.

Other researchers are making devices that overcome the diffraction limit using so-called metamaterials, which bend light in unnatural ways, or nanoscale metal gratings, which capture light through surface interactions. The new lenses, developed by researchers at the Pohang University of Science and Technology in Korea, overcome the diffraction limit because of their size. The lenses are flat on one side and spherical on the other and range in diameter from about 50 nanometers to three micrometers.

The size of each lens is on the same length scale as the wavelength of light that it interacts with, meaning that "the usual optics don't hold," says Chee Wei Wong, head of the Optical Nanostructures Laboratory at Columbia University in New York, who helped evaluate the lenses' performance. And it is the first time the properties of a spherical lens this small have been tested, says Kwang Kim, head of the Center for Superfunctional Materials at Pohang University, who led the research. "No ideal nanoscale lens was available in the past," says Kim.

Kim's team makes the tiny spherical lenses by evaporating a solution containing cup-shaped organic molecules. First, the molecules, which are based on carbon rings, are dissolved in an organic solvent; then water is added, and the solution is allowed to slowly evaporate. During the evaporation process, the organic molecules form crystalline nanotubes that form the lenses. By changing the temperature and the evaporation rate, Kim says, it is possible to control the lenses' ultimate size. Once the lenses have formed, they're stable. The work is described in a paper published today in the journal Nature.

"They found a nice way of building a lens," says Nicholas Fang, assistant professor of mechanical science and engineering at the University of Illinois at Urbana-Champaign. Spherical lenses are ordinarily made using multistep lithography to create a mold that is then patterned with polymers and heated, he says. The nanolenses' index of refraction--how the speed of light changes as it moves through them--is also impressive, says Fang.

To examine the properties of the lenses, the Korean researchers manipulated them using the tip of an atomic-force microscope, placing them on various surfaces for imaging or lithography. To demonstrate imaging beyond the diffraction limit, the lenses were used in conjunction with an optical microscope to resolve the details of a chip patterned with metallic stripes 220 nanometers apart. Without the lenses, this microscope, with a resolution limited to about 320 nanometers, couldn't resolve the same stripes. Further imaging studies showed that the lenses could be used to magnify objects by about 2.5 times. And when the lenses were used to focus ultraviolet light for lithography, they could resolve spots as small as 100 nanometers in the open air (the normal limit is about 192 nanometers).

The lenses also work well for near-infrared light, which is used for telecommunications. Infrared-light detectors generally aren't as sensitive as those for other wavelengths, says Columbia's Wong. To demonstrate the sensitivity of their lenses in this range, the Korean team placed a lens on top of a near-infrared light-emitting nanoparticle called a quantum dot and demonstrated improved detection efficiency.

A limitation of these nanolenses, as for other superlenses, is that they work only in what's known as the near field. That is, they can only focus light onto or gather light from objects in extremely close physical proximity, and must be placed on top of the surface or held just hundreds of nanometers from it. Before the nanolenses can be made into practical devices, this problem will need to be addressed.


http://www.technologyreview.com/computing/23040/

Cuil Tries to Rise Again

Last year's "Google-killer" plans a comeback with social search.

By David Talbot


One year ago, the search engine Cuil exploded on the launchpad. Hyped as a "Google-killer," the site stumbled as its servers crashed and its algorithms spat out irrelevant search results.

Social search: Beyond general search returns (shown in gray), Cuil will provide a subset of results from users' social networks (box, upper right); clicking a face calls up the details (blue box).
Credit: Cuil

Now, the Menlo Park, CA, startup hopes to stage a comeback in part by being the first search engine to pass search queries through users' social networks to generate socially enhanced search results as a companion to regular ones. If, for example, a user searches for the band Green Day--and if she has allowed Cuil to access her Facebook account or any other social networking account--she'll see a special box on the results page, showing those in her network who like Green Day and similar bands. The feature is expected to go live by the end of August.

"We are trying to leverage the information found on users social networks to enhance search results. This is similar to what Amazon or eBay already does: 'People who bought this book, also liked this one,' " says Seval Oz Ozveren, Cuil's vice president of finance and business development. "I think there has been a lot of buzz about this whole idea of social search, but nobody has actually done it to date."

Of course, many social-networking sites already let users search within their networks. And other search engines are trying to expand into social networks. A search company called Worio, for example, offers a Facebook application that generates recommended Web links, akin to search results, based on analyses of the news feeds and other information from a user's social network. If several of your friends live in or are talking about Miami, for example, Worio might provide Miami-centric links. The Cuil foray will be different: it will present the social network search returns aside the general ones.

It's far from clear whether Cuil stands much chance of killing off any competitors with its move into social search, says Dan Weld, a computer scientist and search researcher at the University of Washington. However, he says, it's well established that websites tied to trusted members of people's social networks are more likely to be seen as particularly relevant.

"Statistics show that people, especially young people, are much, much more likely to click on a URL if they see it in a blog or Tweet from someone they trust. This clearly has a big impact on Web marketing and is leading a number of companies to develop tools to track and target these social influencers," he says. "But whether it will really jive with search isn't as clear to me."

Concept mapping: Cuil’s recently added features include a “timeline” and “mapline.”
Credit: Cuil

With $33 million in venture backing, Cuil was founded by Stanford computer scientist Tom Costello and a pair of Google alumni: Anna Patterson and Russell Power. Its core claim is that it searches more pages on the Web than anyone else--three times as many as Google. However, this hasn't yet translated into comparable popularity.

To further distinguish itself, Cuil has recently begun offering other kinds of special categories of search returns along with the main ones. In March it introduced a "timeline"--a box on the right side of the page with search returns expressed by relevant date. A search for "Great Depression," for example, brings up a box listing events of the late 1920s and 1930s--from various acts of Congress to the rise of Nazism--culled from pages that include dates. (Google has a prototype of a timeline search tool that can be customized; it produces temporally arranged links to news stories, from Wikipedia content or other sources.)

In June, Cuil also launched a "mapline"--search returns arranged on a map, and not just for obviously geographical searches like "pizzerias in Palo Alto." For example, the "Great Depression" search produces pins on a world map; mousing over these pins (most of which are in North America) yields links to sites that, for example, describe Depression-era crop failures in Saskatchewan and 1930s public-works projects in Oregon.

But the question remains whether any of this will help resuscitate Cuil. According to the analytical firm Compete, shortly after its launch on July 28, 2008, Cuil had 2 million visitors--a figure that cratered to 130,000 by February and has stayed flat since then. However, Ozveren strongly disputes those numbers. She says Cuil's traffic has been doubling every six weeks since February, though she declined to provide alternative numbers.

Explaining the disparity, Ozveren says that Compete does not accurately track "hover-over" activity--previewing a result without clicking through. Hover-over activity represents a growing share of Cuil's traffic, she says. Also, when Cuil launched, it was the only search engine that didn't track and store the Internet protocol addresses of its users' computers. Ozveren argues that Cuil users may therefore be more privacy-minded than most, and therefore less likely to install Compete's website-tracking toolbar.

Still, the numbers are far worse than the hype suggested was possible just one year ago. The foray into social search is one way Cuil is trying to recover.


http://www.technologyreview.com/web/23038/


A Reporter's Moon Trip

The rewards of reporting an epic journey of man are more than the excitement of the moment. The audience shares new perspectives on another world.

By Victor K. McElheny


This article was first published in Technology Review's October/November 1969 issue. It is being published online in celebration of Apollo's 40th Anniversary.

". . . Voyages to the end of man's experience and into the beginning of space are . . . the physical embodiment of the modern age of mental exploration--the age of science . . . in a land where minds and ships can roam beyond the reach of authority, tyrannical forms cannot endure."
Credit: NASA

I cannot remember just when I became convinced that men would land on the moon someday, just as I am now convinced that men will go on and land on other bodies in the solar system.

When I was a child, I gave no special thought to a lunar landing, because Flash Gordon and Buck Rogers (of the 25th century) already were making much longer journeys to imaginary planets. To be sure, the little books from the Hayden Planetarium said that one would be able to leap about remarkably on the moon, but they also told what your weight would be on Mars or Jupiter or Saturn.

A moon-trip definitely was real for me before President Kennedy in 1961 announced the national goal of a lunar landing in this decade (I remember asking myself then whether the nation was so self-doubting, so sick, that it needed such a tonic). When I visited Antarctica as a science reporter in November, 1960, it struck me that the glimpse I was getting of icy emptiness was the closest I would ever come to the feeling of walking on the lunar surface.

Often since then I have rolled that thought around in my mind, as a way of expressing the sense of the extreme which Antarctica gives. But I never was prepared for the familiarity of the view when the ghostly dots and lines from the little television camera on the moon spread across a screen in the large auditorium of the Manned Spacecraft Center near-Houston, Texas, the night of July 20,1969.

The Benignity of an Age of Science
It is to be present at events like the televising of the moon-walk and to write about them that I became a science reporter almost as soon as I graduated from college in 1957. I believe that events in science and en­gineering are the keys to the world in which I exist.

The first science story which truly excited me was medical. In Charlotte, N.C., where I was working at the time, I happened to see a closed-circuit television broadcast of an open-heart operation, in 1957 still an experimental procedure. A surgeon in Philadelphia, whose voice could be heard along with a kibitzing panel of leading heart surgeons, cut open the patient's chest to reveal a beating heart, throbbing about wildly in the open air. I reflected then that until open heart surgery had become practical, the largest number of such operations had occurred on top of a pyramid in the Aztec capital, Tenochtitlan, as religious sacrifices. But here a modern physician, with the confidence born of scientific knowledge, was operating on the heart to heal it, not tear it out. To do this, he stopped the beating with a drug and turned over the heart's functions to a heart-lung machine while he scraped out the coronary artery (a number of the panel thought the operation rather unlikely to be useful for long).

There it was, the spirit of experimental investigation linked to the desire to heal. I have never been cured of that image of the essential benignity of an age of science.

Sensing the Quality of Exploration
Despite the fact that a whirlwind of interest in space, set moving by Sputnik, also led to my finding a market for science reporting, I never saw a rocket-firing of any size until November 9, 1967, when the first U.S. Saturn V lifted off from Cape Kennedy, Fla., on a flawless first test of the moon booster.

It was only my third visit to Cape Kennedy. The first had been a brief Air Force Reserve trip aboard a DC-3 in 1962, just before John Glenn's three-orbit flight. (This was less than a year after Yuri Gagarin's one-orbit inaugural of the era of manned space flight--Will the Russians get a man to the moon as quickly after Apollo 11?)

A second visit to Cape Kennedy came on January 28, 1967, just a month after I joined the Boston Globe after three years' reporting abroad for Science magazine. It was the day after three astronauts had suffered an almost-instant death by suffocation in the cabin of an Apollo spacecraft intended for launch the next month. The atmosphere at Cape Kennedy was incongruous. In brilliant midwinter sunshine, a horde of reporters wan­dered around, searching for insights into what had happened. Many of them, like me, knew so little that they had nothing to contribute to the story. I had no en­gineer friends from whom I could obtain even frag­mentary information. I hated the leaden, grief-filled atmosphere of rumor.

My only function, I decided, could be to resist rumors and remind readers that a huge system for going to the moon had been constructed, that such a system could not be perfect, and that its momentum would be slowed but not stopped by the deaths of three astronauts, Virgil Grissom, Edward White and Roger Chaffee. I was helped to make this point when Richard Lyons, then of the New York Daily News and now of the New York Times, showed me an account of remarks made the previous month by Joseph Shea, then Apollo Spacecraft Manager in Houston, in which he noted that some 20,000 failures had showed up during the preparation of the first Apollo spacecraft and that at some point a space engineer, like any other, had to decide when things were good enough.

The weekend thus gave me my first taste of the im­mense difficulty of covering the moon-flight program-- or even of achieving much sense of the quality of what was going on. The program was too huge and too im­portant for me to grasp its many operations easily, or to permit of easy access to important places or people.

This does not mean that the program of the National Aeronautics and Space Administration is some sort of deep dark secret. To be sure, the agency has hundreds of public relations people, under the overall manage­ment of Julian Scheer, who has the rank of Assistant Administrator for Public Affairs. But it is not the job of these people to keep N.A.S.A.'s name out of the papers. Quite the reverse.

The justifications of N.A.S.A.'s program are unusual-- some would say shaky. It may be that going to the moon is inevitable, but many people argue against the urgency of doing it this decade, or even this century. The existence of a large "constituency" for N.A.S.A. in states like Florida, Louisiana, Texas and California where there are big agency installations or contractors' factories is not sufficient shield. The pathway to con­tinued popular support that has evolved is an outpouring of news releases and briefings and tours that is simply stupefying. There is danger of drowning in the thou­sands of pages of releases and the dozens of hours of briefings.

Such an outpouring is not merely "news management." It could not have continued for a decade unless some­body out there--a sizeable fraction of the people of the world--were interested.

This view of Mission Control at the Manned Spacecraft Center in Houston during the Apollo 11 flight suggests the multiplicity of information which is available to the technical direction of the mission. Much of that information--a veritable Niagara, says Mr. McElheny--is also available to the press in the adjoining press room.
Credit: NASA

Information and Insulation
It is this Niagara of information--making the U.S. space program so public that it turns out to be a secret, hidden like the vital piece of paper in Poe's "The Gold Bug" by being displayed in the open--that is the real problem of covering trips to the moon, not N.A.S.A.'s occasional attempts to conceal possible political implications in the award of a large contract or to play down the serious­ness of a rebuke to such a contractor for sloppy work.

But during an Apollo mission, the flood of information is vitally useful. With trifling exceptions, the entire volume of chatter between the astronauts and their controllers on the ground is made available, at first "live" over loudspeakers (or wires into stereo headsets) and then in the form of mimeographed transcripts made available within two hours of the time of the actual transmission.

At least twice a day, the flight controllers for one of three eight-hour shifts in Mission Control meet the press for questions about events during their shift. A reporter can attend such a briefing and ask his own questions; he can listen in from his desk in the nearby newsroom while looking at closed-circuit television; or he can tune in to the briefing over a local FM station which breaks into its running music program with all important Apollo mission transmissions, including briefings. If the re­porter is trying to catch a meal or possibly some sleep, depending on his own deadlines and the sleep-work schedule of the astronauts, he can always fall back on the mimeographed transcript of the briefing.

As a further check on the accuracy of his own ear and also that of the relays of secretaries who make the transcript (there is a tendency for the secretaries to launder the text a bit, despite repeated injunctions from the press), the reporter can either record the transmis­sions himself on his own portable tape recorder or go into N.A.S.A.'s news office and listen to its tape of the proceedings.

All of this means that a reporter covering a moon flight is rather insulated from the quality of the event; and unless he takes care, he may easily fall out of sympathy with the environment and thus allow his copy to go stale. A great deal of time must be spent chained to a work table listening to current transmissions while studying the transcript of past transmissions and brief­ings; going to briefings; and returning to the work table to write stories which are either dictated to the home office over a telephone specially installed at the table for the duration or over nearby pay telephones (often in short supply) or, page by page, over teletypewriter cir­cuits.

After all this, the reporters retire to nearby restaurants and bars in small clannish groups to interview and tease each other according to an elaborate code that is too amorphous to describe.

In such an environment, glimpses of real-live space men, or even of the moon up above, are fleeting.

One means of penetrating a little deeper into things is to use the little telephone on the work table to call up space officials you know and ask them questions. Another is to go see them, either by making a formal request to do so or by direct arrangement. Still another is to take somebody out to dinner at a restaurant well away from the space centers. Better still is to try to arrange interviews with key people at quiet moments when they are not too busy. But most of the time, re­porters with deadlines to meet must be content with a hurried personal question asked immediately after a briefing.

With all this to do, reporters also find themselves in fairly continuous contact with their home offices, which want to know what stories the reporter plans to write, what their leading points are, and why the reporter hasn't included a particularly sensational point already available from the wire services. I think it's fair to say that the people who receive the largest number of phone calls are the reporters from the New York Times, and it is certain that the phone calls are not always ap­preciated.

"Sometimes You Can Push Too Far!"
In such a fevered climate, there isn't much room for spontaneity. I am reminded of how the same issue sur­faced in 1959 on the Iowa farm of Roswell Garst when a horde of several hundred reporters, Harrison Salis­bury in the lead, chased Nikita Khrushchev and Garst across the cornfields.

There is the story that Garst was so annoyed at the ten­sion and the crush that he found time to kick Salisbury in the shin. Somehow, that sort of thing sticks out in an affair as managed as a Soviet leader's visit--or a moon flight--must be. The equivalent event during Apollo 11 came early on the morning of July 21, just after the moon walk, when Julian Scheer angrily ordered a tele­vision camera which was focusing straight at a bunch of sweating reporters frantically beating at their type­writers to be removed from the newsroom. When the camera would not move, the Assistant Administrator for Public Affairs angrily shoved a technician out of the way and began moving the camera, which was still on.

At many points during the flight, it was the custom of television newsmen at Houston to use the busy back­ground of the newsroom during brief newscasts from the Manned Spacecraft Center. But this particular camera had been in a main aisle on an unusually crowded and tense evening for a long time. Immediately under the lights was a group from the French news­paper Le Figaro (which very kindly printed an essay about Apollo 11 which I wrote for the Globe but which it did not have space for). The French reporters, led by the capable Ann Thinesse, uttered not a word of protest. Ann continued to work on one of her sober, stylish dis­patches in longhand. But meanwhile, a technician was telling Mark Bloom of the New York Daily News to bend down out of the way of the camera and when he wasn't quick enough about it the technician said, "Sometimes you can push too far, buddy." Mark thought so, too. He hit the ceiling and went off screaming, something he almost never does, to Scheer. Scheer then acted, to the inexpressible delight of the writer-journalists looking on One "big eye" flickered shut, if only briefly.

Affirming the Events
There is, unavoidably, a good deal of jealousy among writer-journalists toward television, the medium upon which they depend to witness such key events of a flight to the moon as the walk on the surface or the splashdown in the Pacific. A great many reporters, and many of their managers back in the home office, are convinced that more and more people are relying on television, that few people are reading much of the vast number of words they are writing and printing.

Certain it is that most people's view of an event such as Apollo 11 is shaped by what they saw of it on television, no matter how much better informed the best of the writer-journalists are than even the most enthusiastic television commentator, Walter Cronkite (who, quite frankly, makes a good many minor errors that nobody notices because he conveys a sense of personal involve ment in space flights). But it is also certain that people are reading more, not less, about a particular event be­cause they saw it on television; and they are reading with more care, because they feel, with some justice, that they know something on their own.

The more important point is that television not only is evanescent; it also is overwhelming. Too much happens too fast. Television thrusts raw events at people, and they may wish to make more considered judgments. The immediacy of television must be strengthened by analysis and reflection. Only then, a day or a month later, can fleeting impressions be converted into a permanent mental image. For this--and for a significanl proportion of the public--a writer is needed.

"Nowhere are the penalties of an estrangement from nature more apparent than in a place like the moon. . . . In such an extreme environment, many of the definitions of ordinary life must give way. . . . Man must be in sympathy with the surroundings--like Captain Nemo--or they will kill him."
Credit: NASA

It is the writer who reminds the televiewer that Arm­strong not only said, "One small step for a man, one giant leap for mankind," but also, "Isn't this fun?" and that Aldrin's first description of the moon was, "Mag­nificent desolation."

It is the writer who stays up late at night to watch the $50,000 party that President Nixon threw the Apollo 11 astronauts after they emerged from their multi-million-dollar quarantine quarters in Houston on August 13, and to remind television-sated Easterners who hadn't stayed tuned that astronaut Neil Armstrong, in brief remarks near the end of the dinner around 2 a.m. E.D.T., recalled a sign he had seen during the ticker-tape parade that morning in New York. The sign read, "Through you, we touched the moon."

It is the writer who watches a nationally televised press conference with the astronauts on August 12, in which the astronauts said the moon seemed friendly despite its barrenness; who notes that they had apparently come close to being unable to land because they had nearly exhausted their fuel margins; and who puts two and two together and reports the next day that Armstrong was so determined to land that he might have disregarded a warning from Houston not to touch down.

Armstrong made it clear that fuel margins which seemed small were in fact large in view of the circumstances; and that, if he had lost contact with Houston, he would have pressed on to a landing if the trajectory was safe. Armstrong was quietly making clear that the astronaut in charge of a lunar landing vehicle, the apex of a huge technological pyramid, was not a supine passenger.

The Social Power of Exploration
The writer is the special extension of his readers' sensitivities. In the second row of the darkened auditorium in Houston on July 20, I was sitting next to Walter Sulli­van, the Science Editor of the New York Times. He, like me, had opted to watch the moon-walk uninterrupted, in contrast to many other morning-paper reporters in an immense, echoing press room nearby. They were watch­ing the event out of the corner of one eye in a glaringly-lit room, listening to the moon-talk over stereophonic headphones, and clacking away at typewriters.

As it happens, Sullivan is the author of the best general history of Antarctic exploration (Quest for a Continent New York: McGraw-Hill Book Co., 1957). We were both struck by how closely the barren ground of Tranquillity Base, viewed at the low sun angle of a lunar morning, resembled the blue and white snowscape at the South Pole during Antarctic summer.

Of course the resemblance was superficial, an accident of the medium--black and white television--by which most residents of the world's rich nations could bear wit­ness to an event in a way that had never been possible before in the history of exploration. The astronauts themselves said that their surroundings in the Sea of Tranquillity, fancifully named by a 17th-century Italian astronomer, reminded them of a desert in the American southwest. As they spoke through the little two-way radios fitted into their back-pack life-support units, the astronauts were seeing the tawny colors of the moon's surface, of which they brought back ample evidence in many color photographs.

But if the colors were different, there were many other similarities between the moon, whose exploration has just begun, and Antarctica, whose exploration began only 70 years ago, just before the invention of the air­plane.

Like the moon, Antarctica is a remote waste never in­habited by men until an age of scientific exploration. There is no trade with Antarctica and no military use for an expanse of 5.5 million square miles of ice at the southern extremity of the earth, dominating a hemi­sphere which is nearly all water and in which only 10 per cent of the world's people live. A rocket base makes as little sense in Antarctica as it does on the moon. If one is to have rocket bases at all, there are cheaper places closer to home to put them, places where the guardians of the rockets can live with their families, take correspondence courses and quickly replace the rocket's warheads when a better design comes along.

The circling of Antarctica by the ships of Captain Cook in the 1770's, the discovery of Antarctic coasts in the 1840's by Dumont d'Urville, James Clarke Ross and Charles Wilkes, and the attainment of the South Pole on foot by parties under Roald Amundsen and Robert Fal­con Scott in 1911-12--all are landmarks in a living history of human exploration.

This history has reached another of its greatest cli­maxes with the first visit to the moon.

To those who ponder the values of such human achieve­ments, let me simply proclaim that rigid intellectual forms, matching rigid social structures, cannot last in the face of a surprising new fact. It was possible to contest Copernicus' ideas of a group of planets re­volving around the sun until Galileo's use of the tele­scope in studying the moon, and the moons of Jupiter, gave the theories of Copernicus unchallengeable em­pirical support. The work of Galileo, so intimately linked with the mountains of the moon, is a good candidate (among many) for the decisive event which launched the age culminating in a landing on the moon.

The immediate effect of such discoveries may be vanishingly small, even in the Apollo case when hundreds of millions watched it. A moon voyage may seem to count for no more than the fall of Icarus did to the painter Breughel, who depicted a very tiny splash in the midst of an immense landscape. Yet the splash oc­curred. The fact cannot be denied, and the exploration will continue--at however jerky a pace.

It is easy for an artist to mock the strivings of an Icarus. Explorers do not have an easy time giving words to their compulsion for searching out regions where nature shows its face in some extreme way, throwing light on the history and character of the planet on which we exist. Just why explorers, by their wanderings, should go on asking the question, "What is a Planet?" is not clear.

Antarctica, where few things exist except mosses, lichens, a few breeds of insects, seals, gulls and pen­guins, is one such region. The moon is another: lifeless, airless, waterless, lacking a magnetic field, of a different density from Earth, and now known to be covered with a layer of rather glassy dust. Neither Antarctica nor the moon have failed to produce their quota of surprises.

In such an extreme environment, many of the definitions of ordinary life must give way. Only an exceptional few can ever go to such a place. To live in a region of ex­tremes means insulation from the natural environment; human contact with the surroundings must be restricted, remote. Yet, in order to design the protective equipment, someone must know enough about the surroundings to imagine their effect. Man must be in sympathy with the surroundings--like Captain Nemo--or they will kill him. Nowhere are the penalties of an estrangement from nature more apparent than in a place like the moon.

Such voyages to the end of man's experience and into the beginning of space are only the physical embodi­ment of the modern age of mental exploration--the age of science. In such an age, a science like astronomy, which has modest practical importance for navigators, can open men's eyes to the existence of another world. And in a land where minds and ships can roam beyond the reach of authority, tyrannical forms cannot endure.

Victor K. McElheny returned from his assignment in Britain as European Editor of Science in 1967 to become Science Editor of the Boston Globe at least in part so as to have first-hand experience with what he has called man's "majestic" effort to reach the moon and outer space. Since his retirement in 1998 McElheny has published two books, Insisting on the Impossible: The Life of Edwin Land and Watson and DNA: Making a Scientific Revolution. He is currently working on a book about the Human Genome Project.

http://www.technologyreview.com/computing/23041/

Silicon Chip Spots Blood Proteins

A microfluidic chip that integrates a light sensor detects blood proteins.

By Katherine Bourzac


By measuring telltale molecules in the blood, doctors can determine patients' cancer risk, monitor chronic diseases, and estimate the best time to perform in vitro fertilization. But current methods for detecting these molecules are time-consuming and relatively expensive, and they must be done in the lab rather than at a patient's bedside. In hopes of providing a rapid, cheap alternative, a European consortium is developing a device for bedside diagnostics that integrates sensitive optical detectors with sample-handling microfluidics on the same chip. The device is being evaluated on clinical blood samples used to monitor hormone levels prior to in vitro fertilization treatments.

Simple chip: Microfluidic channels carved into a silicon chip are visible in this image as long rectangles. The channels hold waveguides, visible as pink lines, that converge on a single light sensor also integrated on the chip.
Credit: Nemoslab

Other groups are also attempting to make such all-in-one diagnostic chips, using optical methods like the European group or using methods that rely on changes in electrical resistance. Optical methods are inherently more sensitive. However, measuring optical signals usually requires expensive, complex instruments. The European device does not. It features readout instrumentation integrated right on the chip, which makes the device simpler than other optical biomolecule detectors that must be read using something resembling a simplified fluorescence microscope. The European chip can be read out using an on-chip sensor that converts the optical signal into an electrical signal.

"The idea was to develop a small chip that can be read out with simple electronics and detect a number of biomolecules at the same time," says Konstantinos Misiakos, head of the Nemoslab project at Greece's National Center for Scientific Research. The project is being funded by the European Union and a consortium including electronics companies ST Microelectronics (headquartered in Geneva, Switzerland) and Technobiochip (of Naples, Italy).

The sensors are housed in a microfluidic channel carved into a silicon chip. The channel has nine bends, each of which is lined with a distinct silicon nitride waveguide that pipes light across the chip from each of nine light-emitting diodes to a single light-detector. Each waveguide is patterned with a different binding molecule, either an antibody or a strand of DNA selected for its ability to bind to a particular blood biomolecule such as a hormone.

When a blood sample flows into the channel, it passes over the waveguides, and the binding molecules pull their target out of the sample. When the biomolecules stick to the treated surface of the waveguide, the speed of light moving through the waveguide changes, creating a detectable change in the signal that's picked up at the light sensor, which turns it into an electrical signal that can be read out. The prototype device can detect nine biomolecules at a time in blood serum.

"This approach has impressive potential," says Michael McAlpine, assistant professor of mechanical and aerospace engineering and chemisty at Princeton University. However, the European device in its current form doesn't match the sensitivity of other biomolecule sensors that can detect single molecules.

Misiakos says his group is evaluating ways to improve the device's sensitivity, including increasing the length of the waveguides to amplify the optical signal. He expects that the chips would cost less than a dollar each to make in a silicon foundry.


http://www.technologyreview.com/biomedicine/23029/

Light Repels Light

The repulsive side of an optical force could lead to ultra-fast telecommunications.

By Anne-Marie Corley


Demonstrating a fundamentally new optical phenomenon, researchers at Yale University have shown the second half of an optical force that could make silicon photonics devices--such as those used in high-speed communications, network cards, even video and TV cables--faster and more capable.

Optical highway: Yale researchers generated repulsive optical forces by splitting a single beam of light so that each half traveled through a different length of waveguide. Because one half of the beam traveled farther than the other, they arrived in the center region out of phase, causing the two waveguides to repel each other. When the light beams were in phase, they attracted each other. The two triangular shapes at the bottom are the optical input and output ports.
Credit: Mo Li

Results like these showing novel ways to control light "don't come along very often," says Oskar Painter, a microphotonics researcher at Caltech who was not involved in the work. "There's a push to do more with optical components," Painter adds, and the Yale group's results are "totally new."

Scientists theorized in 2005 that tiny beams of light confined on a silicon chip could attract or repel each other when placed in close proximity, similar to the electromagnetic forces between positive and negative charges. Last year a group led by Yale University professor Hong Tang first demonstrated the "attractive" side of this optical force. Now the group has demonstrated the second side of the force, repulsion, which makes its effects reversible.

Previously, says Mo Li, the lead author of the paper published in Nature Photonics, they could "pull" with the force, but they couldn't "push." Now the researchers can do both. The accomplishment opens the possibility of using light to manipulate light in microphotonic devices, rather than using mechanical elements like microheaters or power-hungry optical crystals.

Though the force is too weak to use on larger scales--two laser pointers couldn't attract or repel each other, for example--the optical force operates strongly on the microscale, making it ideal for ultrahigh-speed, all-optical control of nanomechanical devices, according to MIT applied-mathematics professor Steven Johnson. In particular, Johnson points to the importance of being able to switch between attractive and repulsive optical forces, something that has not been experimentally demonstrated before.

Harnessing the optical force should enable faster data transfer in applications like fiber-optic telecommunications, where information can be encoded on multiple wavelengths of light and sped through a single fiber-optic cable in a process called wavelength division multiplexing. This process currently requires converting optical signals to electrical signals for modulation or amplification, and then converting them back to optical signals and sending them on their way. Using light to manipulate the optical signal could eliminate the need for electrical rest stops along the fiber-optic highway. "If you can directly transfer light to light," says Li, "it will be cheaper and faster."

Another problem with current optical multiplexing is that the devices that make the process work are relatively large--taking up prime real estate on silicon wafers--and they have to be engineered with strategically placed microheaters, which use changes in temperature to tune each wavelength of light just right. Such devices are slow and can cause cross-talk. Other light-manipulation techniques use special crystal materials that respond to high-intensity light to change the material properties of photonic devices.

Suspended animation: The researchers suspended two waveguides (the horizontal blue cables) to allow them to move freely under the influence of attractive and repulsive optical forces. The vertical blue structures are photonic crystal waveguide supports.
Credit: Mo Li

The Yale group's approach demonstrates the possibility of manipulating one beam of light with another, right on the chip, without the need for slow, bulky heaters or external crystals. And because of their ability to harness both positive and negative forces, they can now effectively double the range of control over photonics circuitry.

The group used two identical waveguides--the optical equivalents of electronic wires, encasing the light beams moving through them--and suspended them in a central coupling region to allow them to move freely under the influence of the optical force. Then the researchers sent in a beam of laser light, split it in half, and forced one half through a longer path than the other. When the two halves of light recombined, they were out of phase because of having traveled different path lengths. The researchers found that when the light beams were out of phase, their waveguides repelled each other, but when the light was in phase, the waveguides pulled closer together. Because they could change the phase difference between the beams just by tweaking the wavelength of the input laser light, the researchers ended up with a new "knob" to control the optical force in a very simple step.

Though they weren't transferring information or even turning switches on and off, the group successfully demonstrated the existence of--and easy flipping between--both sides of the force. Their next steps, says Tang, will be to build more complex circuits and improve the efficiency of their technique. They'll also try to make the force stronger. "The bigger the force, the better," Tang says.

The benefit of the Yale work, according to Caltech's Painter, is that the researchers demonstrated the forces used for switching, but they also did it in a silicon system. That shows promise for future integration with microelectronics structures that are already processed on silicon chips. With the flexibility to control the forces right on the chip, key functionality would be added to the silicon microphotonics toolkit. The ultimate goal would be all-optical switches and devices, such as an optical bus that transfers information through a CPU with no electronic parts at all.


http://www.technologyreview.com/communications/23024/