Technology bulletin 1209Technology bulletin
July 21, 1997
Chest imaging system uses energy subtraction
A combination of advanced data visualization techniques and precision mechanism design has resulted in a breakthrough medical imaging system. The Fuji FCR 9501ES upright reader, developed by Fuji Medical Systems, U.S.A., produces images of the human chest cavity of unparalleled clarity. The device uses high-energy and low-energy signals in tandem to capture snap-shots of soft tissue and bones on separate imaging plates. Through a push-button process of energy subtraction, physicians are able to view either tissue or bone. David Armstrong, director of Fuji's electronic imaging group, said the system is particularly valuable for examining the chest because tissue abnormalities can be hidden behind the ribs. The practicality of energy subtraction traditionally has been limited by the difficulty in precisely aligning separate sheets of film by hand. The Fuji 9501ES incorporates a mechanism that automatically aligns the film. In addition, the imaging plates and copper filter are integrated into the reader, with no cassette handling required. The reader has the capacity to process 120 image plates per hour. For more information, call (203) 353-0300.
Motor control sans sensors
By many accounts, the induction motor is the most commonly-used electric motor in the world. A Swedish company has adapted its patented natural field orientation (NFO) technology as a cost-effective way to control electric motor speeds without the need for on-board speed sensors. NFO Drives' NFO Controller is primarily designed for induction motors operating in the 1-20 kW range. According to controller designer Ragnar Lund, the application area is currently industrial frequency converters, but NFO Controllers for consumer products, such as washing machines, are in the immediate future. "The circuit functions like a preprogrammed ASIC but lets designers choose their own co-processor," Lund says. "With the NFO Controller, small- and medium-sized manufacturers will have access to an economical solution." The hardware consists of a standard Intel microprocessor preprogrammed with NFO algorithms. The price for a complete circuit is US$22 for quantities of a thousand. For more information, call Ragnar Jonsson, NFO Drives AB, at +46 46 16 8500.
Mechanical process key to YAG laser precision
Developed by the French Atomic Energy Agency, yttrium-aluminum-garnet (YAG) microchip lasers are now in production for use in infrared telemetry applications. The lasers offer peak power output of only a few kilowatts and a divergence of about one milliradian, making them very precise. Sfim ODS was granted an exclusive license to commercialize the YAG laser in 1995. The company's production process starts with a single-crystal rod of yttrium-aluminum-garnet, developed by Grenoble-based Crismatec, measuring approximately 25 mm in diameter. The crystal bar is cut into fine slices one mm thick, each of which is doped with quadrivalent chrome by liquid-phase epitaxy. The rear face of the crystal is polished to eliminate the deposit. "This mechanical operation enables us to adjust the thickness of the layer of saturable absorbent in line with the specifications of the laser," says Jean-Pierre Herriau, sales manager at Sfim ODS. Mirrors are applied directly to the crystal by thermal evaporation or physical vapor deposition. The crystal is then cut up into units of one cubic millimeter using a microsaw: Each disk can yield between 200 and 300 YAG microlasers. For more information, call Jean-Pierre Herriau at +33 1 34 63 39 37.
OnStar is watching you
Motorola has teamed up with General Motors' Vauxhall and the Automobile Association (AA) of the United Kingdom to develop an "intelligent car" communication system. The so-called Vauxhall OnStar system will provide drivers with emergency response, roadside assistance, and other services via a 24-hour Vauxhall information center. The system incorporates Global Positioning System (GPS) receivers along with a custom-fitted cellular phone that operates through the car's audio system. In an emergency, the AA will be able to pinpoint a vehicle broadcasting GPS data over the cell phone. On-line access to traffic and navigation data and digital maps enable Vauxhall operators to provide drivers with recommended route or real-time traffic information. The information can be sent verbally or as a short text message on the phone's screen. OnStar is scheduled to be up and running this fall. The service is expected to expand to include telephone directories and a hotel reservation service. Vauxhall's sister company, Opel, is developing an OnStar system for Germany. For more information, call Jeff Weingard, Motorola, at (312) 372-6045.
Brushless motor keeps guided missiles on-target
Control Techniques Dynamics Ltd. has developed a brushless permanent magnet motor with integral gearbox for incorporation into a High Pressure Pure Air Generator (HPPAG) built by Ultra Electronics Weapon Systems. The HPPAG 320 replaces rechargeable gas bottles used to cool infrared guidance systems on missiles and IR sensor packages carried by combat aircraft. Losing the bottles simplifies logistical support and maintenance and provides life-cycle cost savings. The motors' rare-earth magnets drive the gearbox, which in turn drives the compressor that produces the pure air. The generator can support a single sensor at high altitude or multiple sensors at low altitude. Control Techniques' motor meets UK aerospace and environmental qualifications and has been certified by the U.S. Navy. For more information, call Gill Mears, Wessex Public Relations, +44 1202 601050.
Getting powertrain design tools in a row
Siemens Automotive, Regensburg, Germany, has partnered with Hewlett-Packard Co. to develop the former's powertrain design software into a standardized, integrated toolkit. The understanding, which is expected to evolve into a firm agreement over the next year-and-a-half, will leave HP with exclusive marketing rights for the products in Europe. "Over the past decade, application tools for automotive electronic control systems have become an integral part of the automotive manufacturing process," says Michael Reinfrank, general manager of Siemens' application tools business. "Engine and transmission-control systems cannot be brought into production without a highly sophisticated development platform." According to HP, standardization of these same tools will enable engineers to focus on design challenges rather than tool development. For more information, call Gustav Mayert, Siemens, +49 913-174-6489.
Medical material blocks and breathes
Medical applications often have need of materials that are at once barriers to water, bacteria, and blood and permeable to water vapor. These seemingly incompatible requirements have been met by the Arnitel polyester-based thermoplastic elastomer developed by DSM Engineering Plastics, The Netherlands. Unlike microporous films, Arnitel film does not contain pores that can become blocked over time. The film is chemically inert and resists a variety of common chemicals, including mineral acids, solvents, and oils. It passes the ESZI blood breakthrough and ES22 bacteria impermeability tests. In addition, Arnitel's low modulus provides medical garments produced with it with the desired "silky" feel and drapability. Arnitel can be cast or blown into films between 15 and 30 mum thick. For more information, call Consultek 2 at +31 0 73-521 5592.
Wormgears help hollow out solid aluminum
Engineers at Holroyd Machine Tools, Milnrow, England have developed a set of bespoke wormgears for a machining center manufactured by Marwin Production Systems, Wolverhampton. The Automax machining center is destined for Philadelphia, USA, where it will be used by Boeing to produce long, thin-walled aircraft structural members from solid aluminum. Holroyd has invested in a single-flank error testing machine that performs transmission, lead, and pitch error tests with the worm and the wheel in mesh. Such equipment is important, company officials say, for delivering wormgears with high orders of efficiency. Holroyd claims a world record for wormgear efficiency, a 4:1 ratio set tested at the UK's National Physics Lab that returned a 98.2% efficiency under loads up to 64hp. For more information, Richard Bird, Fairfax Marketing, +44 1274 510304.
Low friction wire is environmentally safe
The manufacture of wire coils typically requires an oil-based lubricant be applied to the surface of the wire to reduce friction. Otherwise, scratches can lead to uneven temperature distribution. Such lubricants must be cleaned off using trichlorethylene, which can be harmful to the environment. Kanthal AB of Sweden has developed a new wire with a modified surface structure that reduces friction to the point where no lubricant is needed during coiling and other forming operations. The new material provides uniform production quality with fewer steps than conventional coiling. Furthermore, wires made from the low-friction material have corrosion and oxidation properties identical to those of standard alloys. In high-temperature applications, where a very clean surface is required, the low-friction wire can be cleaned with water. For more information, call Richard Fareham, Kanthal UK, +44 1782-22-48-00.
Studies address safety issues of rocket propellants
Sandia National Labs, Albuquerque, NM, USA, has initiated studies to explore the safety of certain rocket propellants. Of particular interest are the thermal decomposition properties of ammonium perchlorate (AP) and AP-based composite propellants. Such fuels are commonly used for military tactical and strategic rockets. Researchers Richard Behrens and Leanna Minier developed predictive models of how the propellants respond to fire using thermogravimetric modulated beam mass spectrometry. The technique produces gas, and the buildup of gas pressure causes chemical reactions in propellant and binding agents. The studies examined gas formation rates and the effects on propellants at three different temperature regions. The work, supported by the U.S. Department of defense and Department of Energy, is intended to develop new safety procedures for handling and storing rocket fuels. For information, call Lisbette Cox, Combustion Research Facility, at (510) 294-2322.
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