David Kirkpatrick

April 8, 2010

All nanotech isn’t sexy

Sometimes it’s just about making an existing process a little better. Of course it’s a lot more fun to blog about game-changers and the medical breakthroughs.

The release:

Scientists develop environmentally friendly way to produce propylene oxide using silver nanoclusters

Scientists at the U.S. Department of Energy’s Argonne National Laboratory have identified a new class of silver-based catalysts for the production of the industrially useful chemical propylene oxide that is both environmentally friendly and less expensive.

“The production of propylene oxide has a significant amount of by-products that are harmful to the environment, including chlorinated or peroxycarboxylic waste,” said chemist Stefan Vajda of Argonne’s Materials Science Division and Center for Nanoscale Materials. “We have identified nanoclusters of silver as a catalyst that produce this chemical with few by-products at low temperatures.”

Propylene oxide is commonly used in the creation of plastics and propylene glycols for paints, household detergents and automotive brake fluids.

The study is a result of a highly collaborative team that involved five Argonne Divisions and collaborators from the Fritz-Haber-Institut in Berlin and from the University of Illinois in Chicago, including a collaboration between the experimental effort led by Stefan Vajda and the theoretical analysis led by materials chemist Larry Curtiss and nanoscientist Jeff Greeley.

Large silver particles have been used to produce propylene oxide from propylene, but have suffered from a low selectivity or low conversion to propylene oxide, creating a large amount of carbon dioxide. Vajda discovered that nanoscale clusters of silver, consisting of both three atoms as well as larger clusters of 3.5 nanometers in size, are highly active and selective catalysts for the production of propylene oxide.

Curtiss and Greeley then modeled the underlying mechanism behind why these ultrasmall nanoparticles of silver were so effective in creating propylene oxide. They discovered that the open shell electronic structure of the silver catalysts was the impetus behind the nanoclusters selectivity.

“Propylene oxide is a building block in the creation of several other industrially relevant chemicals, but the current methods of creating it are not efficient,” Curtiss said.

“This is basically a holy grail reaction,” remarked Greeley. “The work opens a new chapter in the field of silver as a catalyst for propene epoxidation,” added Curtiss.


Funding for this project was from the U.S. Department of Energy Office of Science and from the U.S. Air Force Office of Scientific Research. A paper on this work will be published in the April 9 issue of the journal Science.

The Center for Nanoscale Materials at Argonne National Laboratory is one of the five DOE Nanoscale Science Research Centers (NSRCs), premier national user facilities for interdisciplinary research at the nanoscale, supported by the DOE Office of Science. Together the NSRCs comprise a suite of complementary facilities that provide researchers with state-of-the-art capabilities to fabricate, process, characterize and model nanoscale materials, and constitute the largest infrastructure investment of the National Nanotechnology Initiative. The NSRCs are located at DOE’s Argonne, Brookhaven, Lawrence Berkeley, Oak Ridge and Sandia and Los Alamos National Laboratories. For more information about the DOE NSRCs, please visit http://nano.energy.gov.

The U.S. Department of Energy’s Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation’s first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America’s scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science.

Photos are available at http://www.flickr.com/photos/argonne/4502854661/ and http://www.flickr.com/photos/argonne/4503484446/

February 12, 2010

Nanoparticles, optics and electricity

(Number one of two posts on nanotechnology and electricity. Hit this link for part two)

This sounds like a tech with a range of applications.

The release:

Penn material scientists turn light into electrical current using a golden nanoscale system

IMAGE: Material scientists at the Nano/Bio Interface Center of the University of Pennsylvania have demonstrated the transduction of optical radiation to electrical current in a molecular circuit.

Click here for more information.

PHILADELPHIA –- Material scientists at the Nano/Bio Interface Center of the University of Pennsylvania have demonstrated the transduction of optical radiation to electrical current in a molecular circuit. The system, an array of nano-sized molecules of gold, respond to electromagnetic waves by creating surface plasmons that induce and project electrical current across molecules, similar to that of photovoltaic solar cells.

The results may provide a technological approach for higher efficiency energy harvesting with a nano-sized circuit that can power itself, potentially through sunlight. Recently, surface plasmons have been engineered into a variety of light-activated devices such as biosensors.

It is also possible that the system could be used for computer data storage. While the traditional computer processor represents data in binary form, either on or off, a computer that used such photovoltaic circuits could store data corresponding to wavelengths of light.

Because molecular compounds exhibit a wide range of optical and electrical properties, the strategies for fabrication, testing and analysis elucidated in this study can form the basis of a new set of devices in which plasmon-controlled electrical properties of single molecules could be designed with wide implications to plasmonic circuits and optoelectronic and energy-harvesting devices.

Dawn Bonnell, a professor of materials science and the director of the Nano/Bio Interface Center at Penn, and colleagues fabricated an array of light sensitive, gold nanoparticles, linking them on a glass substrate. Minimizing the space between the nanoparticles to an optimal distance, researchers used optical radiation to excite conductive electrons, called plasmons, to ride the surface of the gold nanoparticles and focus light to the junction where the molecules are connected. The plasmon effect increases the efficiency of current production in the molecule by a factor of 400 to 2000 percent, which can then be transported through the network to the outside world.

In the case where the optical radiation excites a surface plasmon and the nanoparticles are optimally coupled, a large electromagnetic field is established between the particles and captured by gold nanoparticles. The particles then couple to one another, forming a percolative path across opposing electrodes. The size, shape and separation can be tailored to engineer the region of focused light. When the size, shape and separation of the particles are optimized to produce a “resonant” optical antennae, enhancement factors of thousands might result.

Furthermore, the team demonstrated that the magnitude of the photoconductivity of the plasmon-coupled nanoparticles can be tuned independently of the optical characteristics of the molecule, a result that has significant implications for future nanoscale optoelectronic devices.

“If the efficiency of the system could be scaled up without any additional, unforeseen limitations, we could conceivably manufacture a one-amp, one-volt sample the diameter of a human hair and an inch long,” Bonnell said.


The study, published in the current issue of the journal ACS Nano, was conducted by Bonnell, David Conklin and Sanjini Nanayakkara of the Department of Materials Science and Engineering in the School of Engineering and Applied Science at Penn; Tae-Hong Park of the Department of Chemistry in the School of Arts and Sceicnes at Penn; Parag Banerjee of the Department of Materials Science and Engineering at the University of Maryland; and Michael J. Therien of the Department of Chemistry at Duke University.

This work was supported by the Nano/Bio Interface Center, National Science Foundation, the John and Maureen Hendricks Energy Fellowship and the U.S. Department of Energy.

February 1, 2010

Clean coal in Texas

Who’d a guessed this

From the link:

Could Texas, whose governor dismisses global warming and opposes climate legislation, deliver the world’s first carbon-neutral coal-fired power plant? That looks increasingly likely thanks to a $1.75 billion project in West Texas that received a signed agreement last week for a $350 million grant from the U.S. Department of Energy.

The project, being developed by Bainbridge Island, WA-based Summit Power Group, combines carbon capture with domestic oil production, giving the plant something that few carbon capture and storage projects enjoy: demand for its greenhouse gas emissions. Summit plans to build a 400-megawatt power plant at its site in Penwell, TX, capture 90 percent of the emissions, and sell the nearly three million tons per year of carbon dioxide to oil fields across the Southwest. Oil and gas operators increasingly inject high-pressure carbon dioxide into their aging oil wells to reduce the oil’s viscosity and thus accelerate production, a process known as enhanced oil recovery (EOR). “If we build this there won’t be any more dirty coal plants built,” says Laura Miller, the former Dallas mayor who leads the project for Summit.

Of course that last statement gives me a lot of pause on the entire endeavor. Laura Miller was the worst Dallas mayor in living memory by quite a long shot.

January 20, 2010

Solar shingles are about to become a market reality

Filed under: Business, Science — Tags: , , , , — David Kirkpatrick @ 2:14 am

Courtesy of Dow Chemical. Solar power has a lot of implementation issues, not the least of which is just getting solar panels installed. This looks like a big step in the right direction. These aren’t going to be cheap right off the bat, but they are going to remove a lot of installation issues from going solar on a building.

From the link:

Dow Chemical is moving full speed ahead to develop roof shingles embedded with photovoltaic cells. To facilitate the move, the U.S. Department of Energy has backed Dow’s efforts with a $17.8 million tax credit that will help the company launch an initial market test of the product later this year.

In October 2009, the chemical giant unveiled its product, which can be nailed to a roof like ordinary shingles by roofers without the help of specially trained solar installers or electricians. The solar shingles will cost 30 to 40 percent less than other solar-embedded building materials and 10 percent less than the combined costs of conventional roofing materials and rack-mounted solar panels, according to company officials.

Sunny future: Dow Chemical hopes to transform the solar power industry by integrating solar cells with conventional roofing shingles .

Credit: Dow Chemical

April 9, 2009

Nanotech and wireless communication

Number two of the release dump. Nanotechnology improving wireless communication.

The release:

Nano changes rise to macro importance in a key electronics material

By combining the results of a number of powerful techniques for studying material structure at the nanoscale, a team of researchers from the National Institute of Standards and Technology (NIST), working with colleagues in other federal labs and abroad, believe they have settled a long-standing debate over the source of the unique electronic properties of a material with potentially great importance for wireless communications.

The new study* of silver niobate not only opens the door to engineering improved electronic components for smaller, higher performance wireless devices, but also serves as an example of understanding how subtle nanoscale features of a material can give rise to major changes in its physical properties.

Silver niobate is a ceramic dielectric, a class of materials used to make capacitors, filters and other basic components of wireless communications equipment and other high-frequency electronic devices. A useful dielectric needs to have a large dielectric constant—roughly, a measure of the material’s ability to hold an electric charge—that is stable in the operating temperature range. The material also should have low dielectric losses—which means that it does not waste energy as heat and preserves much of its intended signal strength. In the important gigahertz range of the radio spectrum—used for a wide variety of wireless applications—silver niobate-based ceramics are the only materials known that combine a high, temperature-stable dielectric constant with sufficiently low dielectric losses.

It’s been known for some time that silver niobate’s unique dielectric properties are temperature dependent—the dielectric constant peaks in a broad range near room temperature in these ceramics, which makes them suitable for practical applications. Earlier studies were unable to identify the structural basis of the unusual dielectric response because no accompanying changes in the overall crystal structure could be observed. “The crystal symmetry doesn’t seem to change at those temperatures,” explains NIST materials scientist Igor Levin, “but that’s because people were using standard techniques that tell you the average structure. The important changes happen at the nanoscale and are lost in averages.”

Only in recent years, says Levin, have the specialized instruments and analytic techniques been available to probe nanoscale structural changes in crystals. Even so, he says, “these subtle deviations from the average are so small that any single measurement gives only partial information on the structure. You need to combine several complementary techniques that look at different angles of the problem.” Working at different facilities** the team combined results from several high-resolution probes using X-rays, neutrons and electrons—tools that are sensitive to both the local and average crystal structure— to understand silver niobate’s dielectric properties. The results revealed an intricate interplay between the oxygen atoms, arranged in an octahedral pattern that defines the compound’s crystal structure, and the niobium atoms at the centers of the octahedra.

At high temperatures, the niobium atoms are slightly displaced, but their average position remains in the center—so the shift isn’t seen in averaging measurements. As the compound cools, the oxygen atoms cooperate by moving a little, causing the octahedral structure to rotate slightly. This movement generates strain which “locks” the niobium atoms into off-centered positions—but not completely. The resulting partial disorder of the niobium atoms gives rise to the dielectric properties. The results, the researchers say, point to potential avenues for engineering similar properties in other compounds.




The work was supported in part by the U.S. Department of Energy and the U.K. Science and Technology Facilities Council.

* I. Levin, V. Krayzman, J.C. Woicik, J. Karapetrova, T. Proffen, M.G. Tucker and I.M. Reaney. Structural changes underlying the diffuse dielectric response in AgNbO3. Phys. Rev. B 79, 104113, posted online March 26, 2009.

** The study required measurements at the Advanced Photon Source at Argonne National Laboratory, the Lujan Neutron Center at Los Alamos National Laboratory and the ISIS Pulsed Neutron and Muon Source at Rutherford Appleton Laboratory (United Kingdom). In addition to NIST, researchers from Argonne, Los Alamos, ISIS and the University of Sheffield contributed to the paper.

March 11, 2009

NASA’s Fermi Telescope and the gamma-ray sky

Cool and interesting release from NASA on its Fermi Telescope and mapping gamma rays.

The release from today:

NASA’s Fermi Telescope Reveals Best-Ever View of the Gamma-Ray Sky

GREENBELT, Md., March 11 /PRNewswire-USNewswire/ — A new map combining nearly three months of data from NASA’s Fermi Gamma-ray Space Telescope is giving astronomers an unprecedented look at the high-energy cosmos. To Fermi’s eyes, the universe is ablaze with gamma rays from sources ranging from within the solar system to galaxies billions of light-years away.

(Logo: http://www.newscom.com/cgi-bin/prnh/20081007/38461LOGO)

“Fermi has given us a deeper and better-resolved view of the gamma-ray sky than any previous space mission,” said Peter Michelson, the lead scientist for the spacecraft’s Large Area Telescope (LAT) at Stanford University, Calif. “We’re watching flares from supermassive black holes in distant galaxies and seeing pulsars, high-mass binary systems, and even a globular cluster in our own.”

A paper describing the 205 brightest sources the LAT sees has been submitted to The Astrophysical Journal Supplement. “This is the mission’s first major science product, and it’s a big step toward producing our first source catalog later this year,” said David Thompson, a Fermi deputy project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md.

The LAT scans the entire sky every three hours when operating in survey mode, which is occupying most of the telescope’s observing time during Fermi’s first year of operations. These snapshots let scientists monitor rapidly changing sources.

The all-sky image released today shows us how the cosmos would look if our eyes could detect radiation 150 million times more energetic than visible light. The view merges LAT observations spanning 87 days, from August 4 to October 30, 2008.

The map includes one object familiar to everyone: the sun. “Because the sun appears to move against the background sky, it produces a faint arc across the upper right of the map,” Michelson explained. During the next few years, as solar activity increases, scientists expect the sun to produce growing numbers of high-energy flares. “No other instrument will be able to observe solar flares in the LAT’s energy range,” he said.

To better show individual sources, the new map was processed to suppress emissions from gas in the plane of our galaxy, the Milky Way. As a way of underscoring the variety of the objects the LAT is seeing, the Fermi team created a “top ten” list comprising five sources within the Milky Way and five beyond our galaxy.

The top sources within our galaxy include the sun; a star system known as LSI +61 303, which pairs a massive normal star with a superdense neutron star; PSR J1836+5925, which is one of many new pulsars, a type of spinning neutron star that emits gamma-ray beams; and the globular cluster 47 Tucanae, a sphere of ancient stars 15,000 light-years away.

Top extragalactic sources include NGC 1275, a galaxy that lies 225 million light-years away and is known for intense radio emissions; the dramatically flaring active galaxies 3C 454.3 and PKS 1502+106, both more than 6 billion light-years away; and PKS 0727-115, which is thought to be a type of active galaxy called a quasar.

The Fermi top ten also includes two sources — one within the Milky Way plane and one beyond it — that researchers have yet to identify. More than 30 of the brightest gamma-ray sources have no obvious counterparts at other wavelengths. “That’s good news. It means we’re seeing new objects,” Michelson said. “It also means that we have lots of work to do.”

NASA’s Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership mission, developed in collaboration with the U.S. Department of Energy and important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden, and the U.S.

For images related to this release and the top ten LAT sources, please visit:


For more information about the Fermi Gamma-ray Space Telescope, please visit:


Photo:  http://www.newscom.com/cgi-bin/prnh/20081007/38461LOGO
AP Archive:  http://photoarchive.ap.org/
PRN Photo Desk photodesk@prnewswire.com
Source: NASA

Web Site:  http://www.nasa.gov/

March 9, 2009

Highest surface area ever

For a porous material, this particular is a nanoporous product.

The release:

New nanoporous material has highest surface area yet

ANN ARBOR, Mich.—University of Michigan researchers have developed a nanoporous material with a surface area significantly higher than that of any other porous material reported to date.

The work, by a team led by associate professor of chemistry Adam Matzger, is described in a paper published online March 6 in the Journal of the American Chemical Society.

“Surface area is an important, intrinsic property that can affect the behavior of materials in processes ranging from the activity of catalysts to water detoxification to purification of hydrocarbons,” Matzger said.

Until a few years ago, the upper limit for surface area of porous materials was thought to be around 3,000 square meters per gram. Then in 2004, a U-M team that included Matzger reported development of a material known as MOF-177 that set a new record. MOF-177 belonged to a new class of materials known as metal-organic frameworks—scaffold-like structures made up of metal hubs linked together with struts composed of organic compounds. Just one gram of MOF-177 has the surface area of a football field.

“Pushing beyond that point has been difficult,” Matzger said, but his group achieved the feat with the new material, UMCM-2 (University of Michigan Crystalline Material-2), which has a record-breaking surface area of more than 5,000 square meters per gram.

The researchers used a technique called coordination copolymerization to produce the new material. Previously, they used the same method to create a similar material, UMCM-1, which was made up of six, microporous cage-like structures surrounding a large, hexagonal channel. By using a slightly different combination of ingredients, Matzger’s group came up with UMCM-2, which is composed of fused cages of various sizes and does not have the channel found in UMCM-1.

“The new structure is a bit surprising and shows how the coordination copolymerization method has real potential for new materials discovery,” Matzger said.

In the quest for new materials capable of compactly storing large amounts of hydrogen, researchers have assumed that increasing the surface area of porous materials will result in greater storage capacity. Interestingly, the hydrogen-holding ability of UMCM-2, while high, is no greater than that of existing materials in the same family, suggesting that surface area alone is not the key to hydrogen uptake. Even so, UMCM-2 is useful for helping define future research directions, Matzger said. “I think we needed this compound to demonstrate that high surface area alone is not enough for hydrogen storage.”




Matzger’s coauthors on the paper are postdoctoral researcher Kyoungmoo Koh and research scientist Antek Wong-Foy. The researchers received funding from the U.S. Department of Energy.

For more information: Adam Matzger: http://www.ns.umich.edu/htdocs/public/experts/ExpDisplay.php?ExpID=1264

Journal of the American Chemical Society: http://pubs.acs.org/doi/abs/10.1021/ja809985t

February 12, 2009

February 2009 media tips from Oak Ridge National Laboratory

The release:

February 2009 Story Tips

(Story Tips Archive)

Story ideas from the Department of Energy’s Oak Ridge National Laboratory. To arrange for an interview with a researcher, please contact the Communications and External Relations staff member identified at the end of each tip.

MICROSCOPY—-STEM in liquid . . . . . .

Researchers at ORNL and Vanderbilt University have unveiled a new technique for imaging whole cells in liquid using a scanning transmission electron microscope. Electron microscopy is the most important tool for imaging objects at the nano-scale–the size of molecules and objects in cells. But electron microscopy requires a high vacuum, which has prevented imaging of samples in liquid, such as biological cells.” The new technique – liquid STEM – uses a micro-fluidic device with electron transparent windows to enable the imaging of cells in liquid. A team led by Niels de Jonge imaged individual molecules in a cell, with significantly improved resolution and speed compared with existing imaging methods. “Liquid STEM has the potential to become a versatile tool for imaging cellular processes on the nanometer scale,” said de Jonge. “It will potentially be of great relevance for the development of molecular probes and for the understanding of the interaction of viruses with cells.” The work was recently described in the on-line Proceedings of the National Academy of Sciences.

BIOLOGY—-Time-saving tool . . . . . .

Scientists studying human health, agriculture and the environment have a powerful new tool to help them better understand microbial processes and how they relate to ecosystems. The GeoChip consolidates into one analysis something that using traditional methods would require dozens of tests and take possibly years to complete, according to co-developer Chris Schadt of ORNL’s Biosciences Division. This lab on a chip features more than 24,000 gene probes that target more than 150 functional gene groups involved in biochemical, ecological and environmental processes. The GeoChip is especially useful for bioremediation of sediments and soils, determining the role of microbes in soil and learning how microbial processes are connected to ecosystem responses to human-induced environmental changes such as temperature, moisture and carbon dioxide. This research was funded by the Department of Energy’s Office of Biological and Environmental Research.


CYBERSPACE—-Thwarting threats . . . . . .

Colonies of cyber robots with unique missions can in near real time detect network intruders on computers that support U.S. infrastructure. These “cybots” created for an ORNL software program called UNTAME (Ubiquitous Network Transient Autonomous Mission Entities) may be especially useful for helping government agencies deter, defend, protect against and defeat cyber-attacks. “What scares us the most isn’t what we can see, but rather what we can’t see,” said Joe Trien of the lab’s Computational Sciences & Engineering Division. “A coordinated cyber attack could disrupt one or more of U.S. critical infrastructures, and these attacks can reach across the world at the speed of light.” Trien led a team of researchers that developed UNTAME.


COMPUTING—-First petascale projects . . . . . .

The National Center for Computational Sciences at Oak Ridge National Laboratory has granted early access to a number of projects to test Jaguar, which has peak performance of 1.6 petaflops and is the most powerful computer in the world for open science. The “Petascale Early Science” period will run approximately 6 months and consist initially of 20 projects, said NCCS Director of Science Doug Kothe. The early phase period seeks to deliver high-impact science results and advancements; harden the system for production; and embrace a broad user community to use the system, Kothe said. Proposals include: modeling to better understand climate change; energy storage and battery technology; cellulose conversion to ethanol; combustion research for more efficient automobile engines; and high-temperature superconductors for more efficient transmission of electricity. Fusion, nuclear energy, materials science, nuclear physics, astrophysics, and carbon sequestration also will be explored. “These early simulations on Jaguar will also help us harden the system for a broader collection of projects later in the year,” said Kothe.

January 23, 2009

Nanoscale lasers and whispering galleries

Big breakthrough in tiny lasers — the apps here include lightening quick communications and data handling (photonics) and optical microchips.

The release:

Plasmonic whispering gallery microcavity paves the way to future nanolasers

The principle behind whispering galleries – where words spoken softly beneath a domed ceiling or in a vault can be clearly heard on the opposite side of the chamber – has been used to achieve what could prove to be a significant breakthrough in the miniaturization of lasers. Ultrasmall lasers, i.e., nanoscale, promise a wide variety of intriguing applications, including superfast communications and data handling (photonics), and optical microchips for instant and detailed chemical analyses.


Researchers with the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and the California Institute of Technology have developed a “whispering gallery microcavity” based on plasmons – electromagnetic waves that race across the surfaces of metals. Such a plasmon wave has very small wavelength compared with the light, enabling the scaling down optical devices beyond diffraction limit of the light. Cavities are the confined spaces in lasers where light amplification takes place and this new micro-sized metallic cavity for plasmons improves on the quality of current plasmonic cavities by better than an order of magnitude.

“We have shown for the first time that metallic microcavities based on surface plasmons can have a large quality factor and can thereby enable ultra-small device fabrication and strong enhancement of the light,” said Xiang Zhang, a mechanical engineer who holds a joint appointment with Berkeley Lab’s Materials Sciences Division and the University of California (UC) Berkeley where he directs the NSF Nano-scale Science and Engineering Center.

“Plasmonic microcavities have uniquely different physical properties when compared to dielectric cavities and can extend microcavity research in entirely new ways, particularly at nanoscale dimensions,” said Kerry Vahala, a physics professor at Cal Tech and authority on photonic devices. “Our work shows that the full potential of this new class of device can be realized with careful design and material control.”

Zhang and Vahala led this collaborative research which is reported in the January 22, 2009 edition of the journal Nature. The paper is entitled: “High-Q surface-plasmon-polariton whispering-gallery microcavity.” In addition to Zhang and Vahala, other authors of the paper were Bumki Min, Eric Ostby, Volker Sorger, Erick Ulin-Avila and Lan Yang.


Surface Plasmons and Whispering Galleries

Just as the energy in waves of light is carried through space in discrete or quantized particle-like units called photons, so, too, is the energy in waves of charged gas (plasma) carried in quantized particle-like packets called plasmons, as they travel along metallic surfaces. When photons excite the collective electron oscillations at the interfaces between metal and dielectric (insulator) materials, they can form yet another quasi-particle called a surface plasmon polariton(SPP). Such polaritons play an important role in the optical properties of metals and can be used to manipulate light on a nanoscale.

“Metal-dielectric materials, also known as plasmonics, can be used to confine an optical field to a very small scale, much smaller than conventional insulators,” said Min, lead author on the Nature paper and former postdoctoral researcher in Zhang’s Lab, now an assistant professor at the Korea Advanced Institute of Science and Technology (KAIST). “This capability, often termed as breaking the light diffraction, is unobtainable with dielectric materials alone.”

The main obstacle to working with plasmonic materials for creating nanoscale lasers has been a low quality or “Q” factor, which is a measure of power loss in the lasing cavity – a laser cavity with a high-Q factor has a low power loss. Enter the whispering gallery phenomenon, which Cal Tech’s Vahala has used to boost the Q factor of dielectric microcavities. Whispering galleries are found in circular or elliptically shaped buildings, such as St. Paul’s Cathedral in London, where the phenomenon was first made famous, or Statuary Hall in the U.S. Capitol building.

The prevailing theory behind why whispering galleries work (first proposed in 1871 by British astronomer George Airy to explain St. Paul’s cathedral) is that sound originating at one point along the circumference of an enclosed sphere is reflected to another point along the circumference opposite the source. Vahala and his group applied this idea to dielectric microcavities, and Zhang and Min along with Ostby, Sorger and Ulin-Avila applied the idea to plasmonic microcavities.


“In these sphere-shaped microcavities, optical waves propagate in a similar way that sound waves propagate in a whispering gallery,” said Zhang. “They continue to circle around the edge of the cavity sphere and smoothness of the edge enhances or boosts the cavity’s Q factor.”

In this study, Zhang and his collaborators created a high-Q SPP whispering gallery microcavity by coating the surface of a high-Q silica microcavity with a thin layer of silver.


Explained Zhang, “Whenever light propagates in a metal it experiences some loss of power and this obviously reduces the performance of a device. Silver is the metal with the lowest loss, that is available.”


Whereas previous plasmonic microcavities achieved a best Q factor below 100, the whispering gallery plasmonic microcavity allows Q factors of 1,376 in the near infrared for SPP modes at room temperature.


“This nearly ideal value, which is close to the theoretical metal-loss-limited Q factor, is attributed to the suppression and minimization of radiation and scattering losses that are made possible by the geometrical structure and the fabrication method,” said Min, who believes that there is still room for plasmonic Q-factor improvement by geometrical and material optimizations.

Min said one of the first applications of the whispering gallery plasmonic microcavity is likely to be the development of a plasmonic nanolaser.

“To build a working laser, it is essential to have both the laser cavity (or resonator) and the gain media,” Min said.  “Therefore, we need a good, high-Q plasmonic microcavity to make a plasmonic nanolaser. Our work paves the way to accomplish the demonstration of a real plasmonic nanolaser.  In addition, fundamental research can also be pursued with this plasmonic cavity, such as the interaction of a single light emitter with plasmons.”

This work was supported by the U.S. Air Force Office of Scientific Research MURI program, and by the NSF Nanoscale Science and Engineering Center.


Berkeley Lab is a U.S. Department of Energy national laboratory located in Berkeley, California. It conducts unclassified scientific research and is managed by the University of California. Visit our website at http://www.lbl.gov.

December 6, 2008

Super ceramic

Lots of great applications for this material.

The release:

December 05, 2008

Scientists Create Tough Ceramic That Mimics Mother of Pearl

Biomimicry – technological innovation inspired by nature – is one of the hottest ideas in science but has yet to yield many practical advances. Time for a change. Scientists with the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) have mimicked the structure of mother of pearl to create what may well be the toughest ceramic ever produced.

The roughness of the alumina/PMMA hybrid ceramic controls the strength of the interfaces, which is critical in determining the material’s overall toughness as it affects the sliding process in the polymeric "mortar" layers.

The roughness of the alumina/PMMA hybrid ceramic controls the strength of the interfaces, which is critical in determining the material’s overall toughness as it affects the sliding process in the polymeric “mortar” layers.

Through the controlled freezing of suspensions in water of an aluminum oxide (alumina) and the addition of a well known polymer, polymethylmethacrylate (PMMA), a team of researchers has produced ceramics that are 300 times tougher than their constituent components. The team was led by Robert Ritchie, who holds joint appointments with Berkeley Lab’s Materials Sciences Division and the Materials Science and Engineering Department at the University of California, Berkeley.

“We have emulated nature’s toughening mechanisms to make ice-templated alumina hybrids that are comparable in specific strength and toughness to aluminum alloys,” says Ritchie. “We believe these model materials can be used to identify key microstructural features that should guide the future synthesis of bio-inspired, yet non-biological, light-weight structural materials with unique strength and toughness.”

The results of this research were reported in the December 5, 2008 issue of the journal Science, in a paper entitled:“Tough, bio-inspired hybrid materials.” Co-authoring the paper with Ritchie were Etienne Munch, Max Launey, Daan Hein Alsem, Eduardo Saiz and Antoni Tomsia.


Naturally Tough

Mother of pearl, or nacre, the inner lining of the shells of abalone, mussels and certain other mollusks, is renowned for both its iridescent beauty and its amazing toughness. Nacre is 95-percent aragonite, a hard but brittle calcium carbonate mineral, with the rest of it made up of soft organic molecules. Yet nacre can be 3,000 times (in energy terms) more resistant to fracture than aragonite. No human-synthesized composite outperforms its constituent materials by such a wide margin. The problem has been that nacre’s remarkable strength is derived from a structural architecture that varies over lengths of scale ranging from nanometers to micrometers. Human engineering has not been able to replicate these length scale variances.

brick and mortar structure of alumina/PMMA hybrid

In the “brick-and-mortar” phase of the alumina/PMMA hybrid, aragonite “bricks” slide past each other to dissipate strain energy while the polymer “mortar” acts as a lubricant.

Two years ago, however, Berkeley Lab researchers Tomsia and Saiz found a way to improve the strength of bone substitutes through a processing technique that involved the freezing of seawater. This process yielded a ceramic that was four times stronger than artificial bone. When seawater freezes, ice crystals form a scaffolding of thin layers. These layers are pure ice because during their formation impurities, such as salt and microorganisms, are expelled and entrapped in the space between the layers. The resulting architecture roughly resembles that of nacre.

“Since seawater can freeze like a layered material, we allowed nature to guide the process by which we were able to freeze-cast ceramics that mimicked nacre,” said Tomsia when this research was reported.

Engineered to be Tough

In this latest research, Ritchie, working with Tomsia and Saiz, refined the freeze-casting technique and applied it to alumina/PMMA hybrid materials to create large porous ceramic scaffolds that much more closely mirrored the complex hierarchical microstructure of nacre. To do this, they first employed directional freezing to promote the formation of thin layers (lamellae) of ice that served as templates for the creation of the layered alumina scaffolds. After the ice was removed, spaces between the alumina lamellae were filled with polymer.

Robert Ritchie (seated) led a research effort in which the microstructure of mother of pearl was mimicked to create what may well be the toughest ceramic ever produced. Collaborating with Ritchie were (from left) Maximilien Launey, Daan Hein Alsem, Eduardo Saiz and Antoni Tomsia.

Robert Ritchie (seated) led a research effort in which the microstructure of mother of pearl was mimicked to create what may well be the toughest ceramic ever produced. Collaborating with Ritchie were (from left) Maximilien Launey, Daan Hein Alsem, Eduardo Saiz and Antoni Tomsia.

“The key to material toughness is the ability to dissipate strain energy,” says Ritchie. “Infiltrating the spaces between the alumina layers with polymer allows the hard alumina layers to slide (by a small amount) over one another when load is applied, thereby dissipating strain energy. The polymer acts as a lubricant, like the oil in an automobile engine.”

In addition to making the lamellar scaffolds, the team was also able to fabricate nacre-like “brick-and-mortar” structures with very high alumina content. They did this by collapsing the scaffolds in a perpendicular direction to the layers then sintering the resulting alumina “bricks” to promote brick densification and the formation of ceramic bridges between individual bricks.

Says Saiz, “Using such techniques, we have made complex hierarchical architectures where we can refine the lamellae thickness, control their macroscopic orientation, manipulate the chemistry and roughness of the inter-lamellae interfaces, and generate a given density of inorganic bridges, all over a range of size-scales.”

Next Step

For ceramic materials that are even tougher in the future, Ritchie says he and his colleagues need to improve the proportion of ceramic to polymer in their composites. The alumina/PMMA hybrid was only 85-percent alumina. They want to boost ceramic content and thin the layers even further. They also want to replace the PMMA with a better polymer and eventually replace the polymer content altogether with metal.

Says Ritchie, “The polymer is only capable of allowing things to slide past one another, not bear any load. Infiltrating the ceramic layers with metals would give us a lubricant that can also bear some of the load. This would improve strength as well as toughness of the composite.”

Such future composite materials would be lightweight and strong as well as tough, he says, and could find important applications in energy and transportation.

This research was supported by DOE’s Office of Science, through the Division of Materials Sciences and Engineering in the Basic Energy Sciences office.

Berkeley Lab is a U.S. Department of Energy national laboratory located in Berkeley, California. It conducts unclassified scientific research and is managed by the University of California. Visit our Website at http://www.lbl.gov/

November 18, 2008

Nanocoating improve industrial energy efficiency

The release from today:


Ames Laboratory project seeks to reduce friction and extend tool life

AMES, Iowa – Friction is the bane of any machine.  When moving parts are subject to friction, it takes more energy to move them, the machine doesn’t operate as efficiently, and the parts have a tendency to wear out over time.

But if you could manufacture parts that had tough, “slippery” surfaces, there’d be less friction, requiring less input energy and the parts would last longer.  Researchers at the U.S. Department of Energy’s Ames Laboratory are collaborating with other research labs, universities, and industrial partners to develop just such a coating.

“If you consider a pump, like a water pump or a hydraulic pump, it has a turbine that moves the fluid,” said Bruce Cook, an Ames Laboratory scientist and co-principal investigator on the four-year, $3 million project. “When the rotor spins, there’s friction generated at the contacting surface between the vanes and the housing, or stator.  This friction translates into additional torque needed to operate the pump, particularly at start-up.  In addition, the friction results in a degradation of the surfaces, which reduces efficiency and the life of the pump.  It takes extra energy to get the pump started, and you can’t run it at its optimum (higher speed) efficiency because it would wear out more quickly.”

Applying a coating to the blades that would reduce friction and increase wear resistance could have a significant effect in boosting the efficiency of pumps, which are used in all kinds of industrial and commercial applications. According to Cook, government calculations show that a modest increase in pump efficiency resulting from use of these nanocoatings could reduce U.S. industrial energy usage by 31 trillion BTUs annually by 2030, or a savings of $179 million a year.

The coating Cook is investigating is a boron-aluminum-magnesium ceramic alloy he discovered with fellow Ames Laboratory researcher and Iowa State University professor of Materials Science and Engineering Alan Russell about eight years ago. Nicknamed BAM, the material exhibited exceptional hardness, and the research has expanded to include titanium-diboride alloys as well.

In many applications it is far more cost effective to apply the wear-resistant materials as a coating than to manufacture an entire part out of the ceramic.  Fortunately, the BAM material is amenable to application as a hard, wear-resistant coating.  Working with ISU materials scientist Alan Constant, the team is using a technique called pulsed laser deposition to deposit a thin layer of the alloy on hydraulic pump vanes and tungsten carbide cutting tools. Cook is working with Eaton Corporation, a leading manufacturer of fluid power equipment, using another, more commercial-scale technique known as magnetron sputtering to lay down a wear-resistant coating.

Pumps aren’t the only applications for the boride nanocoatings. The group is also working with Greenleaf Corporation, a leading industrial cutting tool maker, to put a longer lasting coating on cutting tools.  If a tool cuts with reduced friction, less applied force is needed, which directly translates to a reduction in the energy required for the machining operation.

To test the coatings, the project team includes Peter J. Blau and Jun Qu at one of the nation’s leading friction and wear research facilities at DOE’s Oak Ridge National Laboratory, or ORNL, in Tennessee.  Initial tests show a decrease in friction relative to an uncoated surface of at least an order of magnitude with the AlMgB14-based coating.  In preliminary tests, the coating also appears to outperform other coatings such as diamond-like carbon and TiB2.

In a separate, but somewhat related project, Cook is working with researchers from ORNL, Missouri University of Science and Technology, the University of Alberta, and private companies to develop coatings in high-pressure water jet cutting tools and severe service valves where parts are subject to abrasives and other extreme conditions.

“This is a great example of developing advanced materials with a direct correlation to saving energy,” Cook said. “Though the original discovery wasn’t by design, we’ve done a great deal of basic research in trying to figure out the molecular structure of these materials, what gives them these properties and how we can use this information to develop other, similar materials.”

Funding for both projects is provided by the DOE’s Office of Energy Efficiency and Renewable Energy.  BAM is licensed to Newtech Ceramics, an Iowa based startup company located in Des Moines. The ISU Research Foundation provided nearly $60,000 in funding for development of material samples for marketing as part of the startup effort.

Ames Laboratory is a U.S. Department of Energy Office of Science laboratory operated for the DOE by Iowa State University.  Ames Laboratory creates innovative materials, technologies and energy solutions. We use our expertise, unique capabilities and interdisciplinary collaborations to solve global challenges.


A photograph of an AlMgB14 coating on a steel substrate.  The substrate is the mottled structure on the left-hand side of the photo and the coating is the thin, darker strip running along the edge of the steel.  (The blemishes on the steel are carbide inclusions)  The coating has a thickness of approximately 2 to 3 microns (about 1 ten thousandths of an inch)

A photograph of an AlMgB14 coating on a steel substrate. The substrate is the mottled structure on the left-hand side of the photo and the coating is the thin, darker strip running along the edge of the steel. (The blemishes on the steel are carbide inclusions) The coating has a thickness of approximately 2 to 3 microns (about 1 ten thousandths of an inch)

November 14, 2008

First images of new multi-planet solar system

The release:

Astronomers capture first images of
newly-discovered solar system

LIVERMORE, Calif. — Astronomers for the first time have taken snapshots of a multi-planet solar system, much like ours, orbiting another star.

The new solar system orbits a dusty young star named HR8799, which is 140 light years away and about 1.5 times the size of our sun. Three planets, roughly 10, 10 and 7 times the mass of Jupiter, orbit the star. The size of the planets decreases with distance from the parent star, much like the giant planets do in our system.

And there may be more planets out there, but scientists say they just haven’t seen them yet.

“Every extrasolar planet detected so far has been a wobble on a graph. These are the first pictures of an entire system,” said Bruce Macintosh, an astrophysicist from Lawrence Livermore National Laboratory and one of the key authors of a paper appearing in the Nov. 13 issue of Science Express.We’ve been trying image planets for eight years with no luck and now we have pictures of three planets at once.”

Using high-contrast, near-infrared adaptive optics observations with the Keck and Gemini telescopes, the team of researchers from Livermore, the NRC Herzberg Institute of Astrophysics in Canada, Lowell Observatory, University of California Los Angeles, and several other institutions were able to see three orbiting planetary companions to HR8799.

Astronomers have known for a decade through indirect techniques that the sun was not the only star with orbiting planets.

“But we finally have an actual image of an entire system,” Macintosh said. “This is a milestone in the search and characterization of planetary systems around stars.”

During the past 10 years, various planet detection techniques have been used to find more than 200 exoplanets. But these methods all have limitations. Most infer the existence of a planet through its influence on the star that it orbits, but don’t actually tell scientists anything about the planet other than its mass and orbit. Second, the techniques are all limited to small to moderate planet-star separation, usually less than about 5 astronomical units (one AU is the average distance from the sun to Earth).

In the new findings, the planets are 24, 37 and 67 times the Earth-sun separation from the host star. The furthest planet in the new system orbits just inside a disk of dusty debris, similar to that produced by the comets of the Kuiper belt of our solar system (just beyond the orbit of Neptune at 30 times Earth-sun distance).

“HR8799’s dust disk stands out as one of the most massive in orbit around any star within 300 light years of Earth” said UCLA’s Ben Zuckerman.

In some ways, this planetary system seems to be a scaled-up version of our solar system orbiting a larger and brighter star, Macintosch said.

The host star is known as a bright, blue A-type star. These types of stars are usually ignored in ground and space-based direct imaging surveys since they offer a less favorable contrast between a bright star and a faint planet. But they do have an advantage over our sun: Early in their life, they can retain heavy disks of planet-making material and therefore form more massive planets at wider separations that are easier to detect. In the recent study, the star also is young – less than 100 million years old – which means its planets are still glowing with heat from their formation.

“Seeing these planets directly – separating their light from the star – lets us study them as individuals, and use spectroscopy to study their properties, like temperature or composition,” Macintosh said.

“Detailed comparison with theoretical model atmospheres confirms that all three planets possess complex atmospheres with dusty clouds partially trapping and re-radiating the escaping heat” said Lowell Observatory astronomer Travis Barman.

The planets have been extensively studied using adaptive optics on the giant Keck and Gemini telescopes on Mauna Kea, Hawaii. Adaptive optics enables astronomers to minimize the blurring effects of the Earth’s atmosphere, producing images with unprecedented detail and resolution. LLNL helped build the original adaptive optics system for Keck, the world’s largest optical telescope. Christian Marois, a former LLNL postdoctoral researcher and the primary author of the paper who now works at NRC, developed an advanced computer processing technique that helps to extract the planets from the vastly brighter light of the star.

A team led by Macintosh is constructing a much more advanced adaptive optics system designed from the beginning to block the light of bright stars and reveal even fainter planets. Known as the Gemini Planet Imager (http://gpi.berkeley.edu), this new system will be up to 100 times more sensitive than current instruments and able to image planets similar to our own Jupiter around nearby stars.

“I think there’s a very high probability that there are more planets in the system that we can’t detect yet,” Macintosh said. “One of the things that distinguishes this system from most of the extrasolar planets that are already known is that HR8799 has its giant planets in the outer parts – like our solar system does – and so has ‘room’ for smaller terrestrial planets – far beyond our current ability to see – in the inner parts.”

Founded in 1952, Lawrence Livermore National Laboratory is a national security laboratory, with a mission to ensure national security and apply science and technology to the important issues of our time. Lawrence Livermore National Laboratory is managed by Lawrence Livermore National Security, LLC for the U.S. Department of Energy’s National Nuclear Security Administration.

Near-infrared false-color image taken with the W.M. Keck II telescope and adaptive optics. The three planets are labelled b, c, and d. The colored speckles in the center are the remains of the bright light from their parent star after image processing.

Near-infrared false-color image taken with the W.M. Keck II telescope and adaptive optics. The three planets are labelled b, c, and d. The colored speckles in the center are the remains of the bright light from their parent star after image processing.

Oak Ridge National Laboratory media tips for November

The release:

Story tips — Oak Ridge National Laboratory November 2008

ENERGY — Powering the Big Apple . . .

High temperature superconductor (HTS) technology developed at Oak Ridge National Laboratory is being used in a $39 million project to boost and secure Manhattan’s power grid. Project HYDRA, partially funded by the U.S. Department of Homeland Security Science and Technology Directorate, seeks to install and field test HTS cable in New York City’s electrical power grid by 2010. ORNL helps design and test the cable which will boost power delivery 30 percent; increase reliability and security; and limit fault currents caused by tree branches, lightning, and other interruptions that hamper the nation’s electric grid. Industrial partners include American Superconductor Corp., which has shipped more than 56,000 feet of wire for the project; Consolidated Edison Co., which operates Manhattan’s power delivery network; and cable manufacturer Ultera, a joint venture between Southwire Co. and nkt cables.

ENERGY — A DST bonus . . .

Extending Daylight Saving Time by four weeks last year reduced U.S. energy consumption by 17 trillion British thermal units, or the equivalent of enough energy to power 100,000 households for a year. That’s according to a report to Congress from the U.S. Department of Energy by researchers at Oak Ridge National Laboratory, Pacific Northwest National Laboratory and National Renewable Energy Laboratory. Researchers sought to quantify the savings resulting from the Energy Policy Act of 2005, which extended the duration of Daylight Saving Time. The extension went into effect in March 2007. The study found that electricity consumption in 2007 decreased by an average of 0.5 percent per day during the extra four weeks, which adds up to 1.3 billion kilowatt hours. Savings in northern regions were greater than in the south, which may be attributable to increased air-conditioning usage. The work is funded by DOE’s Office of Energy Efficiency and Renewable Energy. See the report at: http://www.eere.energy.gov/ba/pba/pdfs/epact_sec_110_edst_report_to_congress_2008.pdf

CLIMATE — Mapping change . . .

Maps showing possible regional impacts of climate change in the Dominican Republic could play a role in setting policy there and beyond. The maps, generated by a group of researchers at Oak Ridge National Laboratory, will be used for climate change policy discussions and published in a future issue of Foreign Policy, a publication widely read by international policy makers. Projected increased temperatures are just one of the extreme regional stresses considered in the comprehensive ORNL study captured in a series of maps that focus on resource scarcity, extreme events and other impacts of climate and population change. The overall study was led by Auroop Ganguly while the maps for the Dominican Republic were primarily generated by Esther Parish with help from Karsten Steinhaeuser, all of the Geographical Information Science and Technology Group. The research was funded by a grant to ORNL from the Institute for a Secure and Sustainable Environment at the University of Tennessee. Foreign Policy magazine is a non-partisan publication recently acquired by the Washington Post Co. from the Carnegie Endowment for International Peace.

SENSORS — Right on target . . .

Keeping track of weapons at nuclear facilities and other installations could get a lot easier with a technology developed by researchers at Oak Ridge National Laboratory and Visible Assets of New Hampshire. The technology, which uses low-frequency magnetic waves to transmit signals from tags installed in a pistol’s grips, solves a huge problem caused by human error during the inventory process. Future system enhancements will make it possible to count the number of shots fired, eliminating any guesswork about when a weapon needs to be serviced or replaced. A team led by Chris Pickett of ORNL’s Global Nuclear Security Technology Division developed the system software and completed the system integration. The team also conducted operational tests and is working with DOE armorers to complete rigorous tests to evaluate the sensor’s performance, durability and security. Those tests will soon be complete, which will clear the path for Department of Energy facilities to purchase the equipment from Sig Sauer, which licensed the technology. Funding was provided by DOE’s Office of Health, Safety and Security.

November 12, 2008

Amex hoping for the dole, GM sinking and oil back in fifties

Here’s a little buffet of economic news —

The latest hopeful for corporate socialism? American Express after reorganizing as a bank holding company.

From the link:

American Express Co. is seeking $3.5 billion in funds under the government’s plan to directly invest in financial firms, according to a Wednesday report in The Wall Street Journal citing unnamed sources.

Earlier this week, American Express received approval from the Federal Reserve to become a bank holding company, which is a similar structure to traditional commercial banks. The credit card company now has access to financing from the Fed and the ability to grow a large deposit base.

The increased funding opportunities through government programs, including the potential $3.5 billion investment, could be a huge boost to American Express as one of its primary sources of funding has nearly disappeared amid the ongoing credit crisis.

Crude has dropped below $56 a barrel.

From the link:

The Energy Department said it expects U.S. consumption of petroleum to drop more severely than any time since 1980 next year, with gasoline use dropping by another 3 percent. Its Energy Information Administration on Wednesday said 2009 petroleum consumption is projected to sink by a further 250,000 barrels per day, or 1.3 percent, more twice that projected in its previous outlook.

Also on Wednesday, the International Energy Agency said more than a trillion dollars in annual investments to find new fossil fuels will be needed for the next two decades to avoid an energy crisis that could choke the global economy.

Light, sweet crude for December delivery fell nearly 6 percent, or $3.50 to settle $56.16 a barrel on the New York Mercantile Exchange, the lowest closing price since January 2007. Oil prices have plunged more than 60 percent in four months from record highs near $150 in July.

And last, but certainly not least, among debate on whether to bail out the Big Three US automakers, General Motors stock closed at its lowest point since 1946 — yes, that’s not a typo nineteen FORTY six.

From that link:

Shares of General Motors plunged another 13% on Tuesday to a 65-year low, closing below the $3 mark for the first time since 1946.

The stock closed Tuesday down 44 cents to $2.92, its lowest close since April 1943.

The Dow Jones industrial average component has lost nearly 40% of its value since Thursday. Shares began their slide on Friday when GM warned that it could run out of cash and posted a $4.2 billion loss.

On Tuesday, the battered automaker unveiled plans to idle nearly 2,000 hourly workers who build engines, transmission systems and body panels, during the first quarter of 2009, according to company spokesman Tony Sapienza. That reduction follows the news, disclosed Friday, that GM will idle another 3,600 hourly workers.

Making matters more complicated, GM will have to keep most of these hourly workers on the payroll during the current labor contract, which runs through September 2011.

September 30, 2008

Most efficient solar cells to date

From KurzweilAI.net — This is yet another in a long string of solar breakthroughs. The most efficient photovoltaic cells yet, converting almost 50% of harvested light into electricity. Kudos to the US Department of Energy’s National Renewable Energy Laboratory.

NREL Solar Cell Sets World Efficiency Record at 40.8 Percent
ElectricalEngineer.com, Sep. 29, 2008Scientists at the U.S. Department of Energy‘s National Renewable EnergyLaboratory (NREL) have set a world record in solar cell efficiency with a photovoltaic device that converts 40.8 percent of the light that hits it into electricity.

The new design uses compositions of gallium indium phosphide and gallium indium arsenide to split the solar spectrum into three equal parts that are absorbed by each of the cell‘s three junctions for higher potential efficiencies.

Read Original Article>>

August 13, 2008

Nanotech and biofuels

Gasification is a biofuel tech that nanotechnology is provided catalysts to create Ethanol from all sorts of biomass. This process is being researched by the U.S. Department of Energy’s Ames Laboratory and Iowa State University.

From the link:

Gasification is a process that turns carbon-based feedstocks under high temperature and pressure in an oxygen-controlled atmosphere into synthesis gas, or syngas. Syngas is made up primarily of carbon monoxide and hydrogen (more than 85 percent by volume) and smaller quantities of carbon dioxide and methane.

It’s basically the same technique that was used to extract the gas from coal that fueled gas light fixtures prior to the advent of the electric light bulb. The advantage of gasification compared to fermentation technologies is that it can be used in a variety of applications, including process heat, electric power generation, and synthesis of commodity chemicals and fuels.

“There was some interest in converting syngas into ethanol during the first oil crisis back in the 70s,” said Ames Lab chemist and Chemical and Biological Science Program Director Victor Lin. “The problem was that catalysis technology at that time didn’t allow selectivity in the byproducts. They could produce ethanol, but you’d also get methane, aldehydes and a number of other undesirable products.”

A catalyst is a material that facilitates and speeds up a chemical reaction without chemically changing the catalyst itself. In studying the chemical reactions in syngas conversion, Lin found that the carbon monoxide molecules that yielded ethanol could be “activated” in the presence of a catalyst with a unique structural feature.

In this transmission electron micrograph of the mesoporous nanospheres, the nano-scale catalyst particles show up as the dark spots. Using particles this small (~ 3nm) increases the overall surface area of the catalyst by roughly 100 times.

In this transmission electron micrograph of the mesoporous nanospheres, the nano-scale catalyst particles show up as the dark spots. Using particles this small (~ 3nm) increases the overall surface area of the catalyst by roughly 100 times.

In this transmission electron micrograph of the mesoporous nanospheres, the nano-scale catalyst particles show up as the dark spots. Using particles this small (~ 3nm) increases the overall surface area of the catalyst by roughly 100 times.


Major solar breakthrough at NREL

This is exciting news for alternative energy.

From the PhysOrg.com link:

Scientists at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) have set a world record in solar cell efficiency with a photovoltaic device that converts 40.8 percent of the light that hits it into electricity. This is the highest confirmed efficiency of any photovoltaic device to date.

The inverted metamorphic triple-junction solar cell was designed, fabricated and independently measured at NREL. The 40.8 percent efficiency was measured under concentrated light of 326 suns. One sun is about the amount of light that typically hits Earth on a sunny day. The new cell is a natural candidate for the space satellite market and for terrestrial concentrated photovoltaic arrays, which use lenses or mirrors to focus sunlight onto the solar cells.

July 15, 2008

Nanotech improves hydrogen generation

Filed under: Science, Technology — Tags: , , , , , — David Kirkpatrick @ 10:28 pm

A more green method of creating hydrogen is outlined in this press release from Penn State:

Researchers generate hydrogen without the carbon footprint

A greener, less expensive method to produce hydrogen for fuel may eventually be possible with the help of water, solar energy and nanotube diodes that use the entire spectrum of the sun’s energy, according to Penn State researchers.

“Other researchers have developed ways to produce hydrogen with mind-boggling efficiency, but their approaches are very high cost,” says Craig A. Grimes, professor of electrical engineering. “We are working toward something that is cost effective.”

Currently, the steam reforming of natural gas produces most of our hydrogen. As a fuel source, this produces two problems. The process uses natural gas and so does not reduce reliance on fossil fuels; and, because one byproduct is carbon dioxide, the process contributes to the carbon dioxide in the atmosphere, the carbon footprint.

Grimes’ process splits water into its two components, hydrogen and oxygen, and collects the products separately using commonly available titanium and copper. Splitting water for hydrogen production is an old and proven method, but in its conventional form, it requires previously generated electricity. Photolysis of water solar splitting of water has also been explored, but is not a commercial method yet.

Grimes and his team produce hydrogen from solar energy, using two different groups of nanotubes in a photoelectrochemical diode. They report in the July issue of Nano Lettersthat using incident sunlight, “such photocorrosion-stable diodes generate a photocurrent of approximately 0.25 milliampere per centimeter square, at a photoconversion efficiency of 0.30 percent.”

“It seems that nanotube geometry is the best geometry for production of hydrogen from photolysis of water,” says Grimes

In Grimes’ photoelectrochemical diode, one side is a nanotube array of electron donor material – n-type material – titanium dioxide, and the other is a nanotube array that has holes that accept electrons – p-type material – cuprous oxide titanium dioxide mixture. P and n-type materials are common in the semiconductor industry. Grimes has been making n-type nanotube arrays from titanium by sputtering titanium onto a surface, anodizing the titanium with electricity to form titanium dioxide and then annealing the material to form the nanotubes used in other solar applications. He makes the cuprous oxide titanium dioxide nanotube array in the same way and can alter the proportions of each metal.

While titanium dioxide is very absorbing in the ultraviolet portion of the sun’s spectrum, many p-type materials are unstable in sunlight and damaged by ultraviolet light, they photo-corrode. To solve this problem, the researchers made the titanium dioxide side of the diode transparent to visible light by adding iron and exposed this side of the diode to natural sunlight. The titanium dioxide nanotubes soak up the ultraviolet between 300 and 400 nanometers. The light then passes to the copper titanium side of the diode where visible light from 400 to 885 nanometers is used, covering the light spectrum.

The photoelectrochemical diodes function the same way that green leaves do, only not quite as well. They convert the energy from the sun into electrical energy that then breaks up water molecules. The titanium dioxide side of the diode produces oxygen and the copper titanium side produces hydrogen.

Although 0.30 percent efficiency is low, Grimes notes that this is just a first go and that the device can be readily optimized.

“These devices are inexpensive and because they are photo-stable could last for years,” says Grimes. “I believe that efficiencies of 5 to 10 percent are reasonable.”

Grimes is now working with an electroplating method of manufacturing the nanotubes, which will be faster and easier.



Working with Grimes are Gopal K. Mor, Oomman K. Varghese and Karthik Shankar, research associates; Rudeger H. T. Wilke and Sanjeev Sharma, Ph.D. candidates; Thomas J. Latempa, graduate student, all at Penn State; and Kyoung-Shin Choi, associate professor of chemistry, Purdue University.

The U.S. Department of Energy supported this research.

July 11, 2008

A whole slew of nanotechnology news

In a departure from the usual format, here’s a roundup of nanotech news from the last two days of KurzweilAI.net’s e-newsletter. There’s so much here these bits are taken straight from the email.

Controlling the Size of
Nanoclusters: First Step in Making
New Catalysts
KurzweilAI.net July 10, 2008
Researchers from the U.S.
Department of Energy’s (DOE)
Brookhaven National Laboratory and
Stony Brook University have
developed a new instrument that
allows them to control the size of
nanoclusters — groups of 10 to 100
atoms — with atomic precision. The
device could allow for making
nanoclusters with predetermined
size, structure and…

Nanotubes Hold Promise for
Next-Generation Computing
Wired July 9, 2008
Two groups of researchers have
recently published papers
demonstrating advances in creating,
sorting and organizing carbon
nanotubes so they can be used in
electronics. Stanford electrical
engineers addressed the problem of
getting nanotubes straightened out
so they could be put to work in
chips, by growing the nanotubes on
crystalline quartz,…

Assembling Nanotubes
Technology Review July 10, 2008
Stanford University and Samsung
Advanced Institute of Technology
researchers have developed a new
method for sorting single-walled
carbon nanotubes by electronic type
and arranging them over a large
area; it could be useful for
manufacturing high-performance
displays and other electronic
devices. (Melburne LeMieux /
Stanford University)…

Nanotubes bring artificial
photosynthesis a step nearer
New Scientist news service July 11, 2008
Carbon nanotubes are the crucial
chemical ingredient that could make
artificial photosynthesis possible,
say Chinese researchers. Artificial
photosynthesis could efficiently
produce hydrogen that could be used
as a clean fuel and also mop up
carbon dioxide from the atmosphere.
By covalently bonding a large number
of phthalocyanine molecules…