DN Staff

December 2, 1997

8 Min Read
Technology bulletin

Physicists cook up new recipe for chips

They do their baking at temperatures that would melt steel, and use ingredients that would corrode the best cookware. However, physicists Glen Slack and Leo Schowalter at Rensselaer Polytechnic Institute have found a way to serve up aluminum nitride crystals big enough to slice into semiconductor substrates. No one else has been able to do this successfully. Aluminum nitride is an excellent substrate for creating wide band-gap semiconductors for wireless communications and power-industry applications, Schowalter notes. And because aluminum nitride withstands very high temperatures, this substrate material can be used for microelectronic devices on jet engines. Such substrates also would improve the production of blue and UV lasers that could be used to squeeze a full-length movie onto a CD. "Slack demonstrated that you can grow these crystals in a tungsten crucible at 2,300C," Schowalter explains. "At that temperature, the aluminum attacks the grain boundaries in the tungsten. Unfortunately, the crucible doesn't survive very long." The two have solved the problem, but won't give away their trade secret. Instead, they have created their own company, Crystal IS Inc., with the help of a $60,000 Small Business Grant. FAX (518) 276-6091.


Tagging technology to help companies battle piracy

Buyers of compact discs, computer software, recorded movies, and designer clothing can rest assured they got what they paid for--if Tracer Detection Technology Corp. hits the market with its new counterfeit-deterrence system. The technology, developed at Oak Ridge National Laboratory (ORNL), employs a non-chemical tagging agent that is difficult to duplicate, but easy to scan using a simple optical scanner. Tracer, based on Long Island, NY, recently signed an agreement giving it sole commercial rights to ORNL's Fluorescent Dichroic Fiber tagging technique. The lab's Mike Ramsey and Leon Klatt, working for the U.S. Bureau of Engraving and Printing, developed the technology. The dichroic feature means the fibers have different absorption properties for light of the same color, but polarized in different directions. The fibers can be colored or colorless, and exhibit fluorescence only if illuminated by light of the proper polarization. FAX Ron Walli at (423) 574-0595.


'Revolutionary' process provides alternative to open-molding

Molded Fiber Class Co. (Union City, PA) has introduced a patented molding process that Pete Emrich, vice-president of technology, calls revolutionary. Named VACRIMTM, "this unique process will provide a value-added alternative to conventional open-molding processes," adds Jim Graham, president-general manager of MFG/Union City. "The benefits are just enormous." Being a closed molding process, the VACRIM system virtually eliminates all stryrene emissions into the atmosphere. In addition, glass fibers are contained within the molding area, making for a cleaner, healthier workplace. As an added benefit to customers, according to Emrich, the process allows greater flexibility in the size of parts molded, lower part costs, lower overall tooling costs, and greater latitude in material selection and specification. The system creates a finished surface on both sides of the molded part. FAX (814) 438-2284.


Chemistry yields compounds that solve attacks by oils

A new class of thermoplastics elastomer (TPEs) is said to provide exceptional oil resistance and very rubber-like properties--a combination previously available only in TPEs costing 25 to 50% more per pound. That's the word from Teknor Apex (Pawtucket, RI) in introducing its Flexalloy(R) OR (oil resistant) TPEs. The PVC/elastomer blends exhibit softness, elasticity, and tactile properties comparable to other TPEs in the same price range, notes Phil Morin, Teknor Apex industry manager. He adds: "Formulating and compounding advances have eliminated swelling, shrinkage, or disintegration after prolonged exposure to oils." The blends are based on "new resin and stabilization technology, as well as advanced polymeric modifiers," explains Dexi Weng, the company's polymer development chemist. Expected applications include: automotive, wire and cable, and other products exposed to hydrocarbon-based oils, animal fat, automotive fluids, and other aggressive substances. FAX (401) 725-8095.


Process puts composites in a 'common man' use category

A new process developed by Applied Sciences Inc. (Cedarville, OH) could significantly reduce the cost of certain polymeric and carbon-fiber-matrix composite materials. The new fibers, called Pyrograf IIITM, measure 150 times smaller in diameter, but in finished form exhibit similar strength, stiffness, thermal conductivity, and lightweight properties as conventional carbon-fiber components, says Applied Science President Max Lake. The discontinuous fibers are produced directly from a hydrocarbon in the presence of a catalyst. ASI worked with the Air Force's Wright Laboratories in Dayton, OH, to advance the technology. The advance could mean wider use of composites in aerospace and consumer applications, with the cost for conventional carbon fiber dropping as low as $3 per lb compared with an average of about $20 per lb now. FAX (937) 766-5886.


Coating promises improved detection of dangerous materials

Sandia National Laboratories and the University of New Mexico have jointly developed a coating that allows miniature sensors to detect dangerous, even lethal, air- or water-borne molecules much more quickly. The film-like coating--less than one micron thick--barely increases the size of the sensor, says Sandia principal investigator Jeff Brinker. However, the material's extreme porosity increases the sensor's surface area, and therefore its sensitivity--by a factor of about 500. The material, honeycombed by tiny tunnels of precise size, acts as a membrane to separate molecules of differing dimensions. It functions similarly to zeolites--porous crystalline pebbles used by the oil industry to separate out molecules of different sizes. Unlike some zeolites, the Sandia coating, a lightweight gel, must be created artificially. Still, because the gel's molecules self-arrange themselves into a kind of molecular rug, no machinery is need to assemble them. E-mail [email protected].


Acoustic device inspects insulated or uninsulated pipes

Engineers at Pennsylvania State University have developed a new inspection device that uses sound waves to detect and measure corrosion and wall thinning in insulated or noninsulated pipes. The system works on anything from the Alaskan pipeline to a home's water, gas, or sewer lines. The device, which is being patented, can inspect 40 ft of pipe or more at one time, without being moved. It offers 100% cross-sectional coverage, according to Joseph L. Rose, the Paul Morrow Professor in Design and Manufacturing at PSU's College of Engineering. The devise is based on a probe designed to inspect small-bore tubing in nuclear and fossil-fuel steam generators. Both the probe and the device work on the reality that pipes tapped at one location will carry or guide the sound wave so that the tapping can be heard at other locations along its length. E-mail [email protected].


Air-polluting ozone has an honorable clean-up occupation

Though news reports have focused on ozone as an air pollutant, this oxygen variant has a good, lesser-known side. When generated artificially and applied under controlled conditions, ozone can solve a number of pressing environmental problems. The "good-guy" results are based on research findings sponsored by the Electric Power Research Institute (EPRI). The research explored ozone's effectiveness as a disinfectant for drinking water, a bleach and detergent substitute in large-scale laundry facilities, and as a way to treat several kinds of industrial waste. One of the most dramatic EPRI-initiated achievements on the ozone front is an expert panel's recent affirmation of "generally recognized as safe" status for ozone as a sanitizer or disinfectant for foods. Delivered to the FDA, the affirmation clears the way for ozone's use in the $430 billion food processing industry. E-mail [email protected].


Robot responds instantly to long-distance Internet commands

Over the past five years, the Internet has blossomed to become the most recognizable line on the touted Information Superhighway. Now, engineers at Washington University in St. Louis have blazed a new trail that makes the Internet the "Action" Superhighway. T.J. Tarn, professor of systems science and mathematics in the School of Engineering and Applied Science, and doctoral student Kevin Brady, controlled the motions of a robot in Tarn's lab using a joystick located 1,000 miles away in Albuquerque, NM. The three-minute experiment, conducted live before hundreds of engineers who watched on a video monitor at the IEEE Robotics and Automation Society Flagship Conference, involved the Puma robot avoiding a box in its path to perform a manufacturing task. Tarn used sophisticated algorithms for the project that took into consideration the several-second lapse through cyberspace between Albuquerque and St. Louis to avoid any time delay between command and performance. As a result of the accomplishment, Tarn envisions long-distance learning and research opportunities where engineers and scientists, linked to a national lab, could electronically experiment with robots. E-mail [email protected].


Quasi-prepolymers expand low-cost elastomeric applications

New polyurethane elastomers research from Bayer Corporation's Polymers Division and Bayer AG may keep the in-line skating industry rolling along with improved wheel production. The technology also has potential applications in the industrial and transportation industries, as well as other sports and leisure products. The diphenylmethane diisocyanate (MDI) quasi-prepolymers have shown superior physical and dynamic properties, such as high resiliency, low abrasion, and good tear resistance. The materials also offer cost/performance benefits, according to Sanjeev Madan, a development scientist in Bayer Corporation's Polyurethane Specialty Elastomers Group. They can be processed with standard one-shot processing equipment, he explains, "while offering greater control over segregation, reactivities, and homogeneity of casting." E-mail [email protected].

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