Technology Bulletin 211

Innovative technique fingerprints corrosion

Scientists have developed some amazing techniques to fingerprint everything from DNA found in blood at crime scenes to magnetic particles in credit cards. Now, chemical engineers at Washington University in St. Louis have added another fingerprinting technique: corrosion detection. Using a multifaceted signal-processing procedure call wavelets, the researchers can detect two different types of corrosion in metallic equipment, while a monitoring sensor tells process-control engineers where corrosion is taking place in a pipe, vessel, or machinery. It also advises when to replace the part before corrosion reaches a certain level. Current monitoring devices in the oil industry and at power and chemical-refining plants fail to detect corrosion at least 50% of the time, say the researchers. Fax Susan M. Killenberg at (314) 935-4259.

'Smart' material promises safer air travel

Researchers from the Aeroelasticity Branch of NASA and MIT have tested a new technology that could significantly affect the future of air travel. The concept uses piezoelectric "smart" material actuators developed by Active Control experts, and electronic feedback control. The object: to inhibit unwanted vibrations in an aircraft wing. In the test, a flexible composite wing used sensors to detect vibrations, and piezoelectric actuators to oppose vibrational forces. The NASA Langley/MIT team developed a computer control system, using active feedback algorithms, to manage the sensors and actuators and suppress the flutter. Preliminary test results of the wing in a wind tunnel showed a 6% increase in the speed at which the model can safely fly, without encountering such flutter. The technology, say the researchers, could also reduce the transmission of aerodynamic disturbances to an aircraft's fuselage for improved passenger comfort. Fax Adam Bogue at (617) 577-0656.

Aircraft inspection process found reliable

Eddy current inspection, a common way to detect cracks in aircraft, has been shown to be reliable in spotting damage before it becomes severe. So report Sandia National Laboratories researchers who evaluated inspectors for a Federal Aviation Administration study. More than half the inspectors observed at nine major commercial airlines and maintenance facilities achieved detection rates that exceeded 95% for cracks that measure 0.1 inch, the target minimum length for routine detection. With larger cracks, the probability of detection proved even higher. "Many of the inspectors overcame less-than-optimum field inspection conditions, while achieving reliabilities near those obtained under laboratory conditions," adds Floyd Spencer, the report's author. Fax (505) 844-8066.

Green the theme for these red signals

Philadelphia taxpayers are getting relief from higher electric bills. Credit the city "going in the red"-red traffic lights, that is. Chief Engineer John M. O'Connell has underway a program to convert the red lights from energy-hungry incandescent bulbs to light-emitting diodes (LEDs) supplied by R&M Deese, Inc, Anaheim, CA. The switch results in savings of $25 to $50 per light. With 28,000 lights on the streets, eventual savings could reach $1 million or more a year. Moreover, the lamps no longer will need replacing. Once green LEDs make the scene (they still lack the needed light output and cost benefits of their red counterparts), the city could reap another $1 million or more in savings. And, says R&M Deese President Ray E. Deese, "As the range of these LEDs expands, we may see them used in huge billboards." Fax Deese at (714) 666-1459.

Polymers produce electricity from sea power

Ocean Power Technologies, Inc. plans to convert the power of ocean waves into electricity through piezoelectric polymers. When physically strained, these materials have already been used to produce energy in microsensors. Now, Ocean Power will laminate many of its hydropiezoelectric sheets and hang them from rafts anchored to the ocean floor. Strain from the wave action will send electricity to attached electrodes, with special components used to convert the power into dc current. AMP, Inc., a producer of piezoelectric film, likes the concept so much that it has invested in the project. Ocean Power plans to make 1- to 100-kW systems for small coastal communities and offshore oil rigs. Multimegawatt systems loom in the future. Fax Charles Carroll at (609) 924-7220.

World record claimed for solar electricity

A low-cost solar energy technology has set a new commercial-scale energy conversion record. The system, called Integrated High-Concentration Photovoltaics (IHCPV), achieved a solar conversion efficiency greater than 20% in a 2,000W testbed array at the Shenandoah Environment & Education Center of the Georgia Power Co. The system, built by AMONIX, Inc., Torrance, CA, consists of low-cost plastic concentrating lenses to track and focus the sun's rays onto small-area solar cells. By concentrating sunlight 200-500 times, such systems can substantially reduce the cost of silicon cell material needed to generate a given amount of electricity. Fax Dave Roubideaux at (310) 325-0771.

Relief from long-trip seat fatigue on the way

Long-term exposure to vibrations can result in serious health problems for bus and truck drivers. Farid M.L. Amirouche, a mechanical engineering professor at the University of Illinois at Chicago, thinks he has a solution-an active suspension design for a driver's seat. A sensor on the side of the seat, already used in other seat suspension systems, will pick up motions in different vehicle components caused by the road, then send them to a microprocessor. There, a mathematical model that incorporates data on body movement would calculate the force needed to minimize transmission of energy from the vehicle to the driver. The seat would automatically adjust itself before the driver feels a bump. Fax Carolyn Arden at (312) 996-3754.

Eye-drop applicator wards off blindness

Steve Morgan must apply eye drops more than 200 times a day or his eyes would shrivel up and he would go blind. So, when Morgan heard about Tufts University engineer Van Toi Vo's invention of special eyeglasses that automatically eject a tiny amount of medication into the eyes, he wanted to try it. The glasses are outfitted with tiny nozzles aimed at the inner corners of the eyes. Tubes run from the nozzles along the glasses' frame to a cigarette pack-sized box that can be worn in a shirt pocket or on a belt. Inside the box, a tiny motorized pump ejects droplets at programmable intervals or at the push of a button. A microcomputer monitors the system. Morgan tried a prototype device at the Tufts campus with promising results. Vo hopes to land some venture capital to bring the device to market. Fax Vo at (617) 627-3220.

Ceramic composite takes the heat and punishment

Silicon carbide has a history of excellent performance in high-temperature applications. However, few safe, affordable ways exist to fabricate the ceramic into non-brittle composite materials. Rensselaer Polytechnic Institute chemist Leonard Interrante took up the challenge and successfully developed an economical way to produce the illusive materials. It involves placing commercial silicon carbide fibers in a vacuum chamber and infiltrating them with a liquid pre-ceramic polymer known as hydridopolycarbosilane or HPCS. The infiltrated fiber preform is placed in a mold and heated in a two-step procedure that reaches 1,000C. The process is repeated until the composite becomes a solid, armor-hard silicon carbide component. Using Leonard's proprietary process, Walter Sherwood and Christopher Whitmarsh have formed Starfire Systems to produce the material. Sherwood claims the composite is three times lighter than steel and can withstand temperatures that would melt most metals. The firm has already produced armor plate, burner tubes, and hot gas filters under an Army contract. Fax (518) 276-3069.

Research targets improved laser welding

The Big Three automakers and Argonne National Laboratory have joined forces in an attempt to tweak the precision and efficiency of laser-beam welding. The two-year, $920,000 project will focus on developing a system to monitor and control laser-beam welding of steel and stainless-steel auto parts on the shop floor. Plans call for building and testing a prototype system at Argonne, according to scientist Keng Leong. Based on the test result, an advanced version will be developed. Fax Dave Baurac at (708) 252-5274.

Pyrotechnics replace hydraulics for rescue gear

Firefighters and other emergency personnel have access to a new generation of rescue equipment that weighs 70% less and is 70% cheaper than devices currently on the market. The Lifeshear cutter, produced by High-Shear Technology, Torrance, CA, incorporates NASA-developed pyrotechnical technology used in actuated thrusters, explosive bolts, and other items designed for space missions. The unit weighs just 11.5 lbs and uses a 9-gram power unit, making it transportable to even remote areas. Moreover, the device takes only 30 seconds to set up, and requires no pumps or motors to operate. Fax Walt Smith at (310) 325-5354.

Largest hypersonic engine survives key test

The National Aero-Space Plane National Contractor Team has completed testing of its largest scramjet engine, the Concept Demonstration Engine or CDE. Pratt & Whitney, a member of the team, led the test activities at the NASA-Langley Research Center. A scramjet engine operates at hypersonic speeds using supersonic combustion of either hydrogen or hydrocarbon fuel. Most recent tests, 24 in all, included runs at Mach 6.8 and 6.2. More than 1,000 instrumentation sensors monitored the CDE to verify overall performance. "It exceeded all performance expectations," says Ted Langston, P&W's progam manager for the NASP. Fax Patrick W. Lauden at (407) 796-7258.