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Ceramic Tech Today




Three selected for national hypersonic centers

Published on March 31st, 2009 | Edited By: Peter Wray

NASA's Mach 5+ X-43A, first flown on March 27, 2004

NASA’s Aeronautics Research Mission Directorate and the Air Force Research Laboratory’s Office of Scientific Research have tapped the University of Virginia in Charlottesville, Texas A&M University in College Station and Teledyne Scientific & Imaging LLC of Thousand Oaks, Calif. to be the nation’s hypersonic science centers.

The new centers will focus on Mach 5 aircraft using “air-breathing” propulsion. Of special interest to people in the ceramics field is that these centers will be spending a lot of time working on the materials and structures of such aircraft.

“NASA and the Air Force Research Laboratory have made a major commitment to advancing foundational hypersonic research and training the next generation of hypersonic researchers,” said James Pittman, principal investigator for the Hypersonics Project of NASA’s Fundamental Aeronautics Program at NASA’s Langley Research Center in Hampton, Va. “Our joint investment of $30 million over five years will support basic science and applied research that improves our understanding of hypersonic flight.”

Researchers hope to eventually create an engine that could propel aircraft to speeds exceeding 12 times the speed of sound.

Each center will have a different specialty. The UVA center will be the National Center for Hypersonic Combined Cycle Propulsion. Researchers from the University of Pittsburgh, George Washington University, Cornell University, Stanford University, Michigan State University, SUNY Buffalo, North Carolina State University, ATK GASL Inc. (Ronkonkoma, N.Y.), NIST and Boeing will join the UVA effort.

Teledyne Scientific & Imaging will be the National Hypersonic Science Center for Hypersonic Materials and Structures. Team members include researchers from the University of California, University of Colorado in Boulder, the University of Miami, Princeton University, Missouri University of Science and Technology, the University of California, Berkeley and the University of Texas.

Texas A&M’s project, the soon-to-be National Center for Hypersonic Laminar-Turbulent Transition will concentrate in boundary layer control research. It’s partners include researchers from the California Institute of Technology, the University of Arizona, the UCLA and Case Western Reserve University.

In the past, the work by NASA and the AFOSR sometimes overlapped. The announcement about establishing the three centers follows a review of each other’s technology portfolios.

“The Air Force Office of Scientific Research is very excited to continue our partnership with NASA,” said John Schmisseur, manager for the Air Force Office of Scientific Research’s Hypersonics and Turbulence Program. “The centers represent our first effort to sponsor research jointly.”

NASA and the AFOSR will each kick in approximately $15 million to fund the centers at the rate of about $2 million per year per center. The funding can be renewed for up to five years. NASA and AFOSR received more than 60 proposal before selecting UVA, Texas A&M and Teledyne.

Teledyne is clearly pleased with making the cut.

“For over three decades, Teledyne Scientific & Imaging has been a leader in the development of novel materials such as ultra-high performance ceramic composites, polymer composites, and multi-functional materials,” said Robert Mehrabian, chairman, president, and chief executive officer of Teledyne Technologies. “Teledyne is honored by our selection as a National Hypersonic Science Center from an extremely competitive group of respondents. This effort supports Teledyne’s strategy of leadership in areas of fundamental science and technology critical to the U.S. Government.”

According to its abstract, Teledyne says it will lead an effort to “[R]evolutionize the design of hypersonic vehicles by creating a new class of hybrid, hierarchical materials that achieve substantial breakthroughs in oxidation resistance, maximum useable temperature, and maximum supportable heat flux.”

The company says this will cover:

  • Novel routes for combining different materials in tailored morphologies,
  • New experimental methods that will enable the direct visualization of the mechanisms that control a material’s performance,
  • Multi-scale probabilistic model formulations that can simulate mechanisms at all length scales with high fidelity,
  • Novel methods of net-shape processing, and
  • The combination of experiments and multi-scale models into a virtual test system that will transform the way in which materials are designed and qualified.

Ceramic Tech Today




New hydrogen economy book available

Published on March 30th, 2009 | Edited By: Peter Wray


The American Ceramic Society has just published a book on one of the most vibrant areas of energy research and development: Materials Innovations in an Emerging Hydrogen Economy (Ceramic Transactions Volume 202), edited by George Wicks and Jack Simon.

The book is a collection of new papers presented at the 2008 Materials Innovations in an Emerging Hydrogen Economy conference, organized by ACerS and ASM International, and endorsed by The National Hydrogen Association and the Society for Advancement of Material and Process Engineering. It features articles organized into the following five areas:

  • International Overview
  • Storage
  • Production
  • Delivery
  • Leakage Detection/Safety.

This volume is an essential resource for those working on hydrogen-related needs and challenges, including those in academia, government, and industry.

For ordering information, go click here, and the see all of ACerS’ book offerings, check out the Society’s bookstore.

Participants at the 2008 Hydrogen Economy meeting discussed the science and policy issues behind innovations like the emergence of fuel cell-powered vehicles such as this Toyota model that was demonstrated.

Participants at the 2008 Emerging Hydrogen Economy meeting discussed the science and policy issues behind innovations like the emergence of fuel cell-powered vehicles such as this Toyota model that was demonstrated.


Characterization




NIST, University of Colorado discover way to stabilize AFM measurements

Published on March 30th, 2009 | Edited By: Peter Wray

Credit: G.Kuebler/JILA/CU

Credit: G.Kuebler/JILA/CU

NIST and the University of Colorado, operating together as the JILA*, may have just made life a little simpler for those engaged in nano-oriented research by making it easier to use Atomic Force Microscopy.

AFM has become an essential tool in the past two decades because of its ability to build a nanoscale topographic image of a material using a laser and a tiny probe attached to a diving board-like device. Thus far, however, one of the significant downsides to AFM has been its sensitivity to outside “noise” including acoustic noise, vibration and temperature variations. The good news is that the JIAL team believes it has figured out a way to provide “a 100-fold improvement in the stability of the instrument’s measurements under ambient conditions.”

On a practical level, it isn’t surprising that a tool as sensitive as AFM – something that can measure atomic scale physical features and interactions (e.g., bonds) – is also sensitive to the macro conditions within a lab setting. One NIST scientist, Thomas Perkins, put the current situation this way: “At this scale, it’s like trying to hold a pen and draw on a sheet of paper while riding in a jeep.

Until now, this meant that researchers had to invest a lot of time and resources isolating the material and the AFM from outside interference via the use of ultralow temperatures, isolation tables, vacuums, etc. Even these isolation techniques are of no use if the material must be kept in a liquid, as is often the case with biomaterials.

According to a press release, the JILA solution uses a standard AFM probe, but adds two additional laser beams and a precisely marked substrate to sense and respond to the three-dimensional motion of both the test specimen and the probe. The extra beams create a reference system, and any non-material motion of the tip relative to the sample is corrected immediately by compensating for the shift in the substrate.

The method can control the probes position to 40 picometers over 100 seconds, and JILA says it has been able to keep long-term, room temperature drift at 5 picometers per minute, a level they say is a 100-fold improvement over previous ambient-condition AFM measurements.

“This is the same idea as active noise cancellation headphones, but applied to atomic force microscopy,” says Perkins.

An added benefit is that with this reduction in interference, AFM measurements can be performed slower, improving image resolutions by a factor of five.

(* The meaning of “JILA” gets a little confusing and is why I didn’t mention it earlier. It used to stand for Joint Institute for Laboratory Astrophysics, but the joint work between NIST and CU has grown way beyond astrophysics. The term JILA is still used in regard to the joint NIST/CU work, but doesn’t stand for anything anymore.)


Ceramic Tech Today




Ceramics (MEMS) gets fingered

Published on March 26th, 2009 | Edited By: Peter Wray

Apparently ceramics innovations can keep you on your toes – and keep track of your fingers. Florida-based Sonavation Inc. recently announced what they claim to be “the biometrics industry’s thinnest, most durable and highly accurate fingerprint sensor for the wireless and smartcard markets.”

The sensor, dubbed the SonicSlide STS3000 (not to be confused with the infamous MST3000) is based on a ceramic MEMS piezoelectric transducer array. According to Sonavation, the 3 mm array is formed by pillars, “each one-tenth the thickness of a human hair. The pillars have a unique set of properties that enable them to mechanically oscillate when an electric field is applied. The oscillations then register in 256 shades of gray to form the images of ridges and valleys of the fingerprint.”

The entire set of components has been reduced to a single unit 35 mm in length by 14.5 mm wide with a thickness of only 0.25 mm

The company says that a big advantage of their system is that since it’s not a semiconductor, there are no problems associated with electrostatic discharge that have reportedly impaired the use of semiconductor-based sensors in personal electronics such as laptops and mobile phones.

According to its manufacturer, the STS3000 is capable of withstanding more than 10 million swipes and uses less power than comparable system, and uses an ultrasound system that supposedly provides greater accuracy of fingerprint images than available through DC or RF capacitive silicon sensors


Ceramic Tech Today




Video of the week – Electrospinning

Published on March 25th, 2009 | Edited By: Peter Wray

In light of the previous post on the creation of platinum nanowires (as a low-cost fuel cell catalyst) via electrospinning, we stitched together an animation and several demonstrations of electrospinning tiny and nanoscale fibers.

The Flash animation comes to us via Patricia Heiden of Michigan Tech University. The videos come from Michael Boyer at Drexel University, Spinrati (The Electrospinning Gateway) and the IonSource and its video channel on YouTube.

Please note that most of these clips have no audio.


[flashvideo filename=wp-content/video/electrospinning.flv image=wp-content/video/video-static-test.jpg /]


Ceramic Tech Today




Fuel cells: Will a nanowire net cut catalyst costs?

Published on March 25th, 2009 | Edited By: Peter Wray

Platinum nanowires with (left) and without problematic "beads." Credit: Univ. of Rochester

Platinum nanowire net with (left) and without problematic "beads." Credit: Univ. of Rochester

One of the big divides the world of proton exchange fuel cell research is between those who are looking for an alternative to platinum (such as the University of Dayton’s Liming Dai) and those who are sticking with a platinum catalyst.

The pro-platinum group, populated by realists, are quick to acknowledge that ordinary catalyst systems are prohibitively expensive because the cost of the precious metal makes fuel cells containing them unaffordable except for military uses, space applications and specialized research centers. For them, the trick now is to find a way to use the least amount of platinum possible without reducing a fuel cell’s power output. Not surprisingly, they think the platinum Holy Grail can be found in nanotechnology.

Along these lines, one research team from the University of Rochester thinks they may have found the solution: long platinum nanowires.

According to a paper in Nano Letters, the concept is to use wires only 10 nanometers wide but several centimeters long to create a catalytic web of platinum. Lead author James C. M. Li, a professor of mechanical engineering at the university, and graduate student Jianglan Shui says they learned how to produce the long wires using electrospinning techniques.

The platinum nanowires produced by Li are roughly ten nanometers in diameter and also centimeters in length-long enough to create the first self-supporting “web” of pure platinum that can serve as an electrode in a fuel cell.

Much shorter nanowires have already been used in a variety of technologies, such as nanocomputers and nanoscale sensors. But the duo turned to a process known as electrospinning, a relatively old, noninvasive technique that uses an electrical charge to draw very fine (typically on the micro or nano scale) fibers from a liquid or molten material.

It’s easy to understand the attractiveness of electrospinning in this application. The technique is known for producing high surface-to-volume ratios, strong (approaching theoretical maximum strength) and defect-free structures. Li and Shui apparently are able to use this method to create platinum nanowires that are thousands of times longer than any previous such wires.

The electrospinning wasn’t without problems. Initial attempts at it left Li and Shui with platinum beads projecting the platinum nanowires. The beads block the surface of the wires, and if enough are present, large amounts of catalytic surface are effectively inaccessible. “With platinum being so costly, it’s quite important that none of it goes to waste when making a fuel cell,” says Li. “We studied five variables that affect bead formation and we finally got it – nanowires that are almost bead free.

Li and Shui say their approach avoids some of the pitfalls that other researchers have run into when using nanoscale amounts of platinum, such as the tendency of nanoparticles of the metal to merge through surface diffusion, and to become dislodged by oxidation of the support material.

Li says he understands why few have used his long-wire method. “The reason people have not come to nanowires before is that it’s very hard to make them. The parameters affecting the morphology of the wires are complex. And when they are not sufficiently long, they behave the same as nanoparticles,” says Li.
Li and Shui are now working on methods to make the wires longer, more uniform and with even fewer beads. “After that, we’re going to make a fuel cell and demonstrate this technology,” says Li.


Ceramic Tech Today




Birdair to show aerogel membrane roofing systems

Published on March 24th, 2009 | Edited By: Peter Wray

Although there is a tendency to associate aerogel with more exotic applications, one of the frustrations has been finding ways to incorporate the temperamental material into common large-scale manufacturing and applications, such as insulation.

Some enterprises, however, are plugging away at the problems and are succeeding in making greater use of aerogel. One example is the teamwork between Birdair Inc., an Amherst, New York, based contractor that specializes in lightweight long-span roofing systems and tensile structures, Cabot Corp., a Boston based provider of specialty chemicals and high performance materials, and Geiger Engineers.

With the help of Geiger, Birdair developed an architectural fabric membrane that incorporates what the company calls Tensotherm, a composite made with Nanogel, an aerogel product manufactured by Cabot. Sandwiched between layers of Teflon, the membrane is less than a half-inch thick.

The beauty of a roofing system like this is that it is strong, extremely light weight and dampens sound. It also allows for what Birdair calls “daylight harvesting” – letting a large amount of diffuse sunlight to pass through.

Birdair is going to exhibit its roofing systems at the American Institute of Architects (AIA) National Convention and Design Exposition April 30–May 2 at The Moscone Center in San Francisco, CA.

Nanogel is actually Cabot’s trade name for a whole family of silica aerogels. Cabot says it has been producing Nanogel aerogel since 2003 at a plant in Frankfurt, Germany, and claims to be “the only company to develop a commercialized process that allows continuous production of the material under ambient conditions.” Cabot says it is able to manipulate the aerogel’s porosity, pore size and distribution, and bypasses normal drying methods. Beside architectural and building uses, Cabot is marketing its aerogel for use with oil and gas pipelines, coatings, cryogenic materials handling, outdoor apparel and personal care products.

Birdair, Geiger and Cabot announced their first roofing installation using the Tensotherm Nanogel last May at the Dedmon Athletic Center at Radford University in Radford, VA. Donald Geiger, founder of the engineering company, invented a roofing system that is low profile, cable-restrained and air-supported.


Ceramic Tech Today




Solyndra snags big solar loan guarantee offer

Published on March 23rd, 2009 | Edited By: Peter Wray

The DOE promised to act fast in distributing its stimulus monies and it is. It’s been announced that one of the first offers is going to Solyndra, a Fremont, Calif., company with a maverick technology I profiled back in October. A $535 million guarantee will allow the company to obtain lower-than-market financing to expand its production of photovoltaic “panels” by opening a second production plant in California. “Fab 2,” as the new plant is called, is expected to have an annual manufacturing capacity of 500 megawatts per year.

As for the economic stimulus part of the deal, Solyndra says in a press release that, “[C]onstruction of this complex will employ approximately 3,000 people, the operation of the facility will create over 1,000 jobs, and hundreds of additional jobs will be created for the installation of Solyndra PV systems, in the U.S.” Actually, Solyndra’s units are markedly different than other PV units, with a tubular shape that allows each cylinder to collect sunlight from any angle. A coating within the tubes contains the light-sensitive material. By painting a surrounding roof white, the cylinders are capable of capturing reflected sunlight from their “down” side. The tubes also are more tolerant than PV panels when it comes to installation arrangements. Flat panels must be precisely angled with devices that add cost and time, and they must be anchored by ballast or “rooftop penetration” to meet wind-loading requirements. In contrast, Solyndra’s solar tubes can be laid beside each other in straight lines across a roof with minimal rooftop anchoring.

The company says installation costs can be cut in half. Solyndra tubes are made from a less expensive thin-film of semiconductor material. This material – comprised of copper, indium, gallium and selenium – is deposited on a glass tube, which is nested inside another glass tube. The outer tube concentrates sunlight and protects the solar film on the inside tube. See this post for a video of Solyndra’s manufacturing techniques. Under the previous administration, the loan guarantee program got stuck in a horrendous bureaucracy that was so FUBARed that proposals had been sitting for years. New DOE Secretary Chu promised to cut the application approval process to months and cut the application, itself, to less than 50 pages. Chu deserves a nod to sticking to his promise, and so does the DOE for taking a risk with a firm leveraging nontraditional but proven PV technology (and I don’t mean to imply that there is anything wrong with providing loan guarantees to traditional PV panel makers, either).


Characterization




Major efficiency leap possible in sintering [updated]

Published on March 23rd, 2009 | Edited By: Peter Wray

Jingzhe Pan’s predictive sintering technique starts with a model of green compacted ceramic (left) and then projects an anticipated post-sintering dimensions (mesh, right) in comparison to pre-sintering cross section (outside shape). The distortion is caused by heterogeneous density in the green body. The figure shows two predictions, one made by Pan’s technique (solid line) which requires only the densification data. The other (dashed line) used a constitutive law which is difficult and expensive to obtain experimentally. Credit: Univ. of Leicester.

[This post has drawn a lot of attention, and we have updated it with the assistance of Professor Pan] A group of engineers at the University of Leicester in the United Kingdom, led by ACerS member Jingzhe Pan, believe they’ve made a critical breakthrough for improving sintering processes. The group describes their new approach as one that “removes trial and error” in the manufacture of ceramics, and achieves significant time and money savings by using new modeling techniques. Pan describes current sintering approaches as being too inefficient:

“Manufacturing advanced ceramics, even in this era of ‘precision’ techniques, is still very much a ‘trial and error’ process . . . [During sintering], materials are essentially re-packed more closely, such that overall volume decreases, whilst the density increases. Ceramics are intrinsically brittle making post-production alterations in dimensions very difficult. Failure to accurately estimate the final dimensions of ceramic parts, therefore, leads to a waste of materials, time and money.”

Pan notes that predicting change in dimension during sintering using the traditional finite element method requires extensive data on the materials being use, but getting this data can be difficult and expensive. He explains to the Bulletin that,

“Before our work, people thought that a ‘constitutive law’ is always needed to predict sintering deformation. The constitutive law is difficult, time consuming and expensive to obtain experimentally because the measurement requires applying force to the sample during sintering. This is why computer modeling has not been widely used by the ceramic industry.”

His group, instead, discovered that the constitutive law is not always necessary.

“We developed a method to use only the densification data – density as function of time – to predict the sintering deformation. Such data can be obtained by free sintering of small samples with no need to apply force. “[Using this data,] our computer software can predict changes in dimensions, even before production begins. This method does not depend on the physical properties of any one ceramic material. Direct comparison between our predictions with experimental measurements independently obtained by Bouvard’s group at Grenoble and Blanchart’s group at Limoges shows that the method works for both high purity alumina and low purity clays. Our method simply uses densification data from the small sample of the material and extrapolates the data, such that it can be applied to larger quantities used in manufacturing. It can thus, be applied to a wide range of ceramics,” he says.

Pan

He warns that his method is invalid for pressure assisted sintering, such as sinter forging or hot isostatic pressing. Pan acknowledges that his system is not quite ready for prime time, and the human interfaces needs to be simplified and redesigned before it can be marketed and installed in manufacturing settings. The group is also working on getting the system to apply to a broader range of industrial products.

Computer model (left) in comparison with experiment (right). High purity alumina powder compact – comparison between predicted (dashed line) and measured (solid line) profiles. The outer frame shows the initial shape of the section. The experimental measurement was done by H.G. Kim, O. Gilla, P. Doremus and D. Bouvard at the Institut National Polytechnique De Grenoble, France.

Computer model (left) in comparison with experiment (right). Low purity clay compact – comparison between predicted (dashed line) and measured (solid line) profiles. The outer frame shows the initial shape of the section. The experimental measurement was done by Magali Barriere and Philippe Blanchart at Ecole Nationale Supérieure de Céramique Industrielle, France.


Career




Family matters: Parenting, not ability, affects women in math-related careers

Published on March 22nd, 2009 | Edited By: Peter Wray

The under-representation of women in science careers in the United States has been reported before, but a new Cornell University report provides more – but not necessarily startling – details about why this under representation occurs. The Cornell researchers’ conclusion explains the situation along fairly commonsensical lines: The choice to have and raise children unfortunately coincides with difficult career periods.

A good starting point on this issue is a study published last July by the Center for Work-Life Policy. It reported that 52 percent of women in private-sector science and technology jobs drop out without returning. The study also revealed that there was a specific age range, 35-44, where the attrition peaked. This is dropout pattern exists despite evidence that gender differences in science study are starting to level out. According to the National Science Foundation, nearly half of the students pursuing graduate degrees in science, technology, engineering and math are female. In the biological sciences, women dominate at the graduate level, making up 56 percent of the student population.

The Cornell study was actually framed to answer the question of why women tend to choose non-math-intensive fields for their careers. The answer they found indicated that it that the choice had little to do with mathematical ability and a lot to do with wanting the flexibility to engage in parenting and caregiving. “A major reason explaining why women are underrepresented not only in math-intensive fields but also in senior leadership positions in most fields is that many women choose to have children, and the timing of child rearing coincides with the most demanding periods of their career, such as trying to get tenure or working exorbitant hours to get promoted,” said lead author Stephen J. Ceci, professor of human development at Cornell. “These are choices that all women, but almost no men, are forced to make,” said co-author Wendy M. Williams, Cornell professor of human development.

The Cornell study is published in the March issue of the American Psychological Association’s Psychological Bulletin (135:2). It integrated 35 years of research on sex differences in math. The researchers acknowledge that sexism may still be a factor, but as only one of several. “Institutional barriers and discrimination exist, these influences still cannot explain why women are not entering or staying in STEM careers,” said Ceci. “The evidence did not show that removal of these barriers would equalize the sexes in these fields, especially given that women’s career preferences and lifestyle choices tilt them toward other careers such as medicine and biology over mathematics, computer science, physics and engineering.” “Women would comprise 33 percent of the professorships in math-intensive fields if it was based solely on being in the top 1 percent of math ability, but they currently comprise less than 10 percent,” Ceci said.

Policy decisions can lessen the consequences of women who face difficult career-family choices. The authors have drafted several recommendations for new options for women. Their suggestions include delayed or deferred entry to tenure-track positions, part-time-to-full-time transitions in tenure-track work and more frequent use of “courtesy” appointments that would provide enough financial and technical support for women to continue their research from home. P.S. There are many resources about and for women in science. One of the newer ones is “Under the Microscope,” a website developed in 2008 by the Feminist Press and IBM with funding from the National Science Foundation. Besides insightful blog posts, you find links to books such as Base Ten (“I’d recommend this book to anyone, male or female, working in a scientific field and attempting to organize a healthy family life.”) and the Smithsonian’s flickr page of historical photos of women in the sciences.


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