You are browsing the archives of 2009 November.

(Either JavaScript is not active or you are using an old version of Adobe Flash Player. Please install the newest Flash Player.)

Charles Vest, president of the National Academy of Engineering and president emeritus of MIT, was the 2009 Frontiers of Science & Technology–Rustum Roy Lecturer at the recent ACerS Annual Meeting and MS&T’09 conference.

“This is the most exciting time for engineering and science in human history. A new generation of engineers will be inspired by the great human challenges of this century. Globalization and the changing nature of science and technology are driving change and opportunity in higher education, R&D and innovation. R&D spending is smeared nearly uniformly around the world, and new players are rapidly emerging. Higher education is globalizing in both planned and unplanned ways, enabled by information technology and driven by economic and social change. Our innovation system may be due for another major transformation. Do our universities have new responsibilities? Can we pull it off?”

Vest earned a B.S. in mechanical engineering from West Virginia University in 1963, and M.S.E. and Ph.D. in mechanical engineering from the University of Michigan in 1964 and 1967, respectively. He joined the faculty of UM as an assistant professor in 1968, where he taught in the areas of heat transfer, thermodynamics and fluid mechanics, and conducted research in heat transfer and engineering applications of laser optics and holography. He became an associate professor in 1972 and a full professor in 1977.

Vest’s administrative duties at UM included associate dean of engineering from 1981 to 1986. He was dean of engineering from 1986 to 1989, when he became provost and vice president for academic affairs. In 1990 he became president of MIT and served in that position until December 2004. He then became professor and president emeritus.

As president of MIT, Vest was active in science, technology and innovation policy; building partnerships among academia, government and industry; and championing the importance of open, global scientific communication, travel and sharing of intellectual resources.

Vest was a director of DuPont for 14 years and of IBM for 13 years, was vice chair of the U.S. Council on Competitiveness for eight years and served on various federal committees and commissions, including the President’s Committee of Advisors on Science and Technology during the Clinton and Bush administrations. He serves on the boards of several nonprofit organizations and foundations devoted to education, science and technology.

In July 2007 he was elected to serve as president of NAE for six years.

Share

The solar cells at top were made on a roll-to-roll printer from an ink consisting of the rod-shaped inorganic semiconducting nanocrystals shown below. The cells were printed on a flexible metal foil and will be topped with a glass plate. Credit: Solexant

Technology Review reported that solar cells made from nanocrystal-based inks have the potential to be as efficient as the conventional inorganic cells currently used in solar panels, but can be printed less expensively.

Solexant, a company in San Jose currently, is hoping that simpler, cheaper printing processes and materials, as well as lower initial capital costs to build its plants, will give them the leading edge. The company expects to sell modules for $1 per watt, with efficiencies above 10 percent.

To bring down the cost of solar cell manufacturing, companies have been developing thin-film solar cells from semiconductors that don’t match crystalline silicon’s performance but are much less expensive to make.

Solexant’s goal is to make cheap thin-film solar cells with relatively high efficiencies.

Technology Review describes the technology as follows:

The Solexant cells are printed on a metal foil as the substrate. Nanocrystal films are simple to print but have poor electrical properties. Electrons tend to get trapped between the small particles. “The trick with these cells is how to deposit the materials on the fly in a way that makes a very conductive surface,” which in turn ensures decent light-to-electricity conversion, says Alivisatos. Solexant begins with nanocrystals because they’re easier to print, and heats them as they’re printed, causing them to fuse together into larger, high-quality microcrystals that don’t have as many places for electrons to lose their way.

The remaining parts of the solar cell, including the electrical contacts and a light-absorbing layer, are also printed on the flexible metal films. This process allows Solexant to print very large areas. When complete, the cells are cut and then topped with a rigid piece of glass.

Solarexant’s first product, which expects to sell for $1 per watt next year, will contain a single layer of the nanocrystals. The company is currently developing other types of nanocrystals that are more responsive to different bands of the solar spectrum in the hopes of boosting its cells’ efficiency.

Share

Small prototype of Ceramate NaSICON-based battery, about the size of a hand. Credit: Ceramatec

Back in September, Ann reported on Ceramatec’s efforts to develop a low-cost home battery/power storage system. Ceramatec said back then that it had developed a new battery that can be scaled up to store 20 kilowatt-hours — enough to power an average home for most of a day.

I missed it at the time, but Gizmag’s Jeff Salton interviewed Grover Coors (yes, of the well known Coors family - Ceramatec is an offshoot of Coors Brewing), principle researcher at Ceramatec, about the company’s battery R&D efforts, and provides some really good background on how Coors/Ceramatec got into this field. Salton has lots of good detail about the company’s sodium super ionic conductor (NaSICON) material.

Last month, Popular Mechanic’s Joe P. Hasler also dove into this development and interviewed Ceramatec CEO Ashok Joshi, and Hasler was able to squeeze out some additional information.

Check these stories out.

Share

Credit: Int'l. Journal of Applied Ceramic Technology

The online version of ACerS’ International Journal of Applied Ceramic Technology has a new story that reveals many of the problems scientists and engineers face when designing the tips of missiles – called domes – used by primarily by the military, and the results of some interesting research on a new dome material. The gist of the paper in ACT is that a group of Saint-Gobain researchers have found that ultra pure α-alumina powder may provide a superior material for making these domes.

Consider, however, the problems that must be addressed in coming up with a dome material. Besides providing an aerodynamic leading surface for air-to-air and air-to-ground missiles, a missile dome shields an array of sensors that control various systems within the missile. Among other things, some of these sensors are used to detect a variety of electromagnetic radiation (e.g., in both visible and infrared ranges).

The best systems must be able to differentiate, for example, between the signature of the exhaust of a jet engine and the signature of decoy flares that a targeted airplane might jettison. Thus the domes have to be functionally transparent in a fairly wide range of the spectrum. Likewise, the shape and thickness of the domes must be such that they don’t distort any of the incoming electromagnetic radiation.

To complicate things even further, the dome must be able to withstand enormous mechanical stresses and thermal shocks. At the start of a missile launch, friction causes the outside leading surface of the front most portion of the dome to heat more rapidly than the rest. This hot front surface expands more than the cooler internal portions of the doom, and soon there is significant stress between the expanded and the unexpanded material. If the stress exceeds the mechanical strength of the material, the dome shatters.

Some materials work well at lower speeds, but new missiles will soon be rocketing at +Mach 4 levels.

Cost and ability to manufacture/machine are factors, too.

A commonly used material for domes is monocrystalline alumina (i.e., sapphire) and polycrystalline magnesium fluoride. Sapphire is costly, difficult to shape and prone to chipping. Large boules of sapphire must be drawn and then machined, which is an art in itself. A sapphire dome that has all of the required properties is typically 4-5 mm thick. The benefit of sapphire is that is a relative transparent material in the 0.25–5 μm range. However, transparency declines significantly at wavelengths higher than 5 μm.

The transparency of MgF₂ is more limited than sapphire, but does very well in the 2–5 μm range, It is much less expensive than sapphire. Unfortunately, MgF₂ isn’t a particularly rugged material.

So, the question is this: Is there some alternative material with good mechanical/thermo-mechanical strength and transparent in the key IR and visible ranges that is easy to work with and cheaper than sapphire, and a thermal shock resistance better than magnesium fluoride will be of use for this kind of application?

Guillaume Bernard-Granger, Christian Guizard and Nathalie Monchalin, from Saint-Gobain’s Laboratoire de Synthèse et Fonctionnalisation des Céramiques, say domes made of a dense and submicronic form α-alumina powder may be a good and relatively inexpensive alternative.

Comparative thermal shock resistance. Credit: Int'l. Journal of Applied Ceramic Technology

In brief, they were able to document that their alumina material has good transparency in the visible and mid-infrared ranges and can be formed using mold-and-sintering processes rather than complex and delicate machining. Just as importantly, a dome can be made with a thickness as low as 1 mm and still survive Mach 4 speeds.

Overall, this is just a great example of how advanced ceramics, using ultrapure feedstock refined at the submicron and nano levels is providing new, customizable solutions to engineering problems. Read the paper for the details.

Share

MemPro CEO John Finley holds a bit of the ceramic fiber that's at the heart of the company's technology.

According to a press release, MemPro was recently awarded another Small Business Technology Transfer grant from the National Science Foundation for $147,000 — bringing the total the company has received from NSF to $847,000.

Typical catalytic converters rely on expensive metals such as platinum, palladium and rhodium, so industry has long looked for a way to get the same level of catalysis using less of those pricey metals. MemPro’s “nCATfiber” ceramic material works essentially like the catalytic material found in a car – but uses a lot less of the rare metals.

MemPro innovation is that it uses flexible nanoscale ceramic fibers that still contain the catalytic material, but in much small amounts. The nanofibers provide more surface area and can more efficiently use the embedded metals. Company head John Finlay claims MemPro’s ceramic catalytic converters reduce materials cost by 75 percent. MemPro also claims its fibers allow operations at much higher temperatures and are completely recyclable.

Nanofibers holding particles of metal catalysts. Credit: University of Akron, Sneha Swaminathan.)

MemPro’s fibers are produced by electrospinning using advanced techniques developed at and licensed from the University of Akron.

The company is currently marketing its product to the makers of small nonroad engines for consumer goods like lawnmowers, snowblowers and weed whackers. Although currently unregulated, these engines will be required to meet a new set of EPA emission standards by 2012. MemPro says the new grant will allow research on systems for “larger engines, biofuel synthesis, new battery technologies, and removal of hydrogen sulfides from natural gas streams.”

In an interview with the Summit (Colorado) Daily News, Finley said the NSF believes MemPro is doing good things from a technical perspective, but that the company also has a good shot at commercializing what they do. “And NSF likes that because they get money from Congress, and they like to point to successes,” Finley said.

In the following video (at about 50 seconds in), Findley is interviewed and claims their is a potential $10 billion market for converters like his. The video also has displays some samples of the material and a few applications. He also boldly claims that this technology can make coal a “clean” energy source.

Share