Technology bulletin 802

Vacuum chamber brings space down to Earth

In space, nobody can hear you scream. Or jiggle a satellite's balky solar panel. Which is why it is a pretty good idea to get all the kinks out while things are still at arm's reach. National Technical Systems (NTS), Saugus, CA, has recently opened its new 1,500 ft³ thermal vacuum chamber for simulating conditions in space. Capable of attaining vacuum levels of 1x10^-6 torr at sustained temperatures of over 125C, the chamber was designed to test full-size satellites and spacecraft components. Extreme temperatures ranging from 350C to -190C can be attained. Plans are under way to achieve temperatures below -205C. Inside diameter of the chamber shroud is 120 inches. In addition, the chamber is equipped with a number of instruments and facilities for studying the effects of vacuum and temperature, including a 100,000 class clean room. An LN²-cooled cold finger is used to trap elements. A Leybold 0-100 a.m.u. residual gas analyzer is available to detect contaminants as well as aid in system conditioning analysis. A large number of electrical and telecom feedthroughs can be accommodated.

For more information, contact Bradley Carlson at (800) 254-4814.

Compressed natural gas may be the alternative fuel of choice

Cosworth Engineering, Northampton, England, a division of Vickers PLC investigating the benefits and costs of alternative fuels for vehicles, has concluded that compressed natural gas (CNG) and alcohol-based fuels have worldwide potential. In particular, Cosworth believes that CNG development will command most interest in the near future among industrialized nations, while demand for alcohol systems is likely to be restricted to countries where politics or natural resources make them attractive. John McClean, Cosworth's manager of powertrain controls, points out that there are already around one million vehicles worldwide using CNG and that he expects this number to double by the year 2000. Italy and Russia lead the way for CNG vehicles in Europe, with 280,000 and 205,000 respectively. There are only 3,000 CNG vehicles in the rest of Europe. By comparison, there were 41,000 CNG vehicles operating in the U.S. in 1994.

For more information, contact Denise Proctor, Cosworth public affairs, at +44(0) 1604 732274.

Morphing is not just for playtime

Morphing is a hot (but rapidly cooling) Hollywood techno-trick where a character's appearance is changed into something else. Michael Jackson did it in video, the evil Terminator did it in T2, and now it's become a common theme during Saturday morning cereal commercials. The University of Buffalo maintains they have developed a new visualization method called "graph morphing" that permits design engineers to alter complex computer models in the face of changing requirements. Christina Bloebaum, associate professor of mechanical and aerospace engineering, says graph morphing will significantly improve the design process in any industry that produces complex products, such as automobiles, aircraft, and even industrial plants. The technique assigns variables to design features in two or three axes. Engineers are then able to pull these features into new shapes either with traditional input devices or with a virtual reality rig. In addition to aesthetics, graph morphing should help demonstrate the engineering impact of design trade-offs. Because the graphics are rendered in VRML, it is possible to link designers into the same model over the World Wide Web, permitting collaborative morphing.

For more information, contact Christina Bloebaum at (716) 645-2626.

Splitting light gets more points across

A multidisciplinary research effort at MIT has resulted in a photonic band gap (PBG) microcavity resonator, a device that may improve the efficiency and information-carrying capacity of fiberoptic communication systems a hundredfold. The materials and manufacturing techniques used to fabricate the devices are common to the integrated circuit industry. Lionel Kimerling, director of MIT's Materials Processing Center, says the PBG resonators can fit into the already existing network of underground fiberoptic cables. The units act as filters for the control of light by separating it into different color bands, each of which may be used to carry different information. MIT's PBG resonators can separate light into over 100 individual color bands, hence the hundredfold increase in performance. Kimerling says optical PBG resonators have implications for other light-emission applications, such as microlasers and microLEDs.

For more information, contact Lionel Kimerling at (617) 253-5383.

Engineering software vendors need to get with the program

A survey by Daratech, Cambridge, MA, finds CAD/CAM, CAE vendors deficient in keeping up with technologies offered by the World Wide Web. According to Daratech's CAD/CAM, CAE: Survey, Review and Byuers' Guide, The functionality of Web-borne and Java-based component technologies is skyrocketing while engineering and manufacturing users are being left behind. The reason? "A technological backwater of large, top-heavy CAD/CAM, CAE systems that, for all their raw power, lack functions that are basic to home consumers of Web services," says Daratech. A key factor in the explosion of Web technologies and services is the rise of talented developers of component software who are capitalizing on the open, extensible architecture of intranet/Web plug-ins. While CAD/CAM, CAE vendors have been vigorously engaged in adapting select intranet/Web functionality for the engineering and manufacturing market, they have been reluctant to embrace the "plug-in" philosophy wholeheartedly. As a result, engineering users are being trapped in an environment of non-standard components that they may find difficult and expensive to shed.

For more information, contact Bruce Jenkins, Daratech vice president, at (617) 354-2339.

New coating technology sputters along

Engelhard-CLAL, Carteret, NJ, has developed an enhanced SCX sputter coating process for wire, ribbon, and discrete parts. The coating technology enables co-deposition of alloys or compounds that cannot be mechanically worked by other techniques. Noble precious and non-precious metal coatings can be applied. The SCX sputtering process is conducted at low temperatures, permitting deposition on temperature-sensitive materials. The process takes place in an inert gas environment (typically Argon) at low pressure to minimize gaseous entrapments. By substituting a reactive gas, such as hydrogen, nitrogen, or oxygen, it is possible to engineer coatings consisting of metallic compounds. Typical deposition coating thicknesses range from 1/2 micron to over 6 microns.

For more information, contact Donald Toenshoff, sales/marketing manager, at (908) 205-5772.

Composite patch keeps 'em flying

The Federal Aviation Administration (FAA) has certified a process developed at Sandia National Labs, Albuquerque, NM, to patch Lockheed-Martin L-1011 passenger jets. The "bonded composite doubler" patch reinforces a corner of the aircraft's right mid-section access door. The new technique makes use of a flexible, fiber-reinforced composite material that can be adhered to the aircraft's surface. Produced as a thin tape, the material comprises strong parallel boron fibers enmeshed in epoxy. "The advantage of the composite doubler is its flexibility," says Dennis Roach of Sandia's airworthiness assurance department. "With the riveted plates widely in use, stress load transfer occurs exclusively at the doubler's edges. With a composite doubler, stress load transfer occurs gradually by shear through the adhesive layer, creating a more uniform stress field." Also, because each layer of tape is strongest in one direction--parallel to the boron fibers--a composite doubler can be applied in successive plies with directional strength optimized for a particular point. Composite doublers are corrosion-resistant, lightweight, and can be formed into complex shapes without machining, making them easy to apply. A Delta L-1011 receiving the patch is now flying the trans-Atlantic route. Sandia is working on FAA certification for the patch for other types of aircraft, including the 727, 737, and DC-9.

For more information, contact Dennis Roach at (505) 844-6078.

Measuring the wind, from a distance

A prototype non-Doppler optical sensor developed by the Georgia Institute of Technology, Atlanta, accurately measures wind speed over long distances. Test results of the single-ended, long-path laser wind sensor show its measurements of higher wind speed are more accurate than mechanical anemometers, says Mikhail Belen'kii of the Georgia Tech Research Institute. "With some modification the sensor can measure both horizontal and vertical wind speeds," he adds. The sensor consists of a helium neon laser that projects a beam of light onto a reflective target about 100 ft away. A telescope collects the reflected light and two horizontally separated detectors measure the degree of degradation. Originally developed for measuring airborne chemical concentrations in chemical plants, the sensor also holds promise for aviation safety and meteorology.

For more information, contact Mikhail Belen'kii at (404) 894-0140.

Advanced imaging technology taps terahertz bands

A detector capable of receiving terahertz signals has been used to create images in real-time. Researchers at Rensselaer Polytechnic Institute, Troy, NY, have developed the real-time electro-optic terahertz sensor to make use of the extremely large portion of the electromagnetic spectrum between infrared and microwave bands. According to Xi-Chen Zhang, the associate professor of physics who led the development team, the technology may make it possible to image diseased tissue, electric fields, concealed explosives, and other hard-to-view items. The unique detector features a zinc telluride crystal onto which the terahertz radiation is focused after flowing through the target material. Simultaneously, a laser "readout" beam is directed into the system in order to convert the spatial and spectral distributions into visible. The Rensselaer technology has been licensed exclusively to Molecular OptoElectronics Corp. (MOEC) of Watervliet, NY for development into commercial imaging systems.

For more information, contact Michael Shimatzu, MOEC, at (518) 270-8203.