IMPROVED "VISION USING SOUND" SYSTEM WINS R&D 100 HONOR.An inexpensive acoustic wave transducer transducer, device that accepts an input of energy in one form and produces an output of energy in some other form, with a known, fixed relationship between the input and output. developed by NIST (National Institute of Standards & Technology, Washington, DC, www.nist.gov) The standards-defining agency of the U.S. government, formerly the National Bureau of Standards. It is one of three agencies that fall under the Technology Administration (www.technology. mechanical engineers has been selected as one of the top 100 technologies for the year 2000 by Research and Development Magazine. The device, known as the lensless line-focus broadband transducer, helps acoustic microscopes perform ultrasonic ultrasonic /ul·tra·son·ic/ (-son´ik) beyond the upper limit of perception by the human ear; relating to sound waves having a frequency of more than 20,000 Hz. ul·tra·son·ic adj. 1. examinations of alloys, ceramics, crystals, composites and other industrially important materials simply, cheaply and with easier interpretation of the data. The transducer sends a pulsed sound wave through a test sample that is submerged in water. The speed of the reflected wave provides a measure of the material's elasticity (its ability to flex under stress), while the direction of the reflected wave provides details about crystal planes or defects within the material. Current acoustic microscopes use lenses to focus the ultrasonic beam and may cost hundreds of thousands of dollars. The NIST transducer costs less than $500, can be used with conventional ultrasonic systems costing about $20 000 and yields equivalent or better quality data on materials properties This is a list of materials properties. A materials property is an intensive, often quantitative property of a material, usually with a unit that may be used as a metric of value to compare the benefits of one material versus another to aid in materials selection. . The cost savings result from NIST's use of an inexpensive piezoelectric The property of certain crystals that causes them to produce voltage when a mechanical pressure is applied to them such as sound vibrations. This technique is used to build crystal microphones, phonograph cartridges and strain gauges, all of which turn mechanical movement into voltage. , plastic film for the curved transducer. Electrical signals cause the film to emit relatively low-frequency, pulsed sound waves. The curvature of the film focuses the sound waves in the same way that curved mirrors A curved mirror is a mirror with a curved reflective surface, which may be either convex (bulging outward) or concave (bulging inward). Most curved mirrors have surfaces that are shaped like part of a sphere, but other shapes are sometimes used in optical devices. are used in telescopes to focus light from distant stars. The transducer is positioned above the sample and then scanned or rotated through different angles to get a full picture of the material's elastic properties. For technical information on the NIST transducer, contact Gerry Blessing, (301) 975-6627, gblessing@nist.gov. |
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