Technology Bulletin 1315

DN Staff

February 17, 1997

9 Min Read
Technology Bulletin

Space technology spins off knee brace

Engineers at NASA's Marshall Space Flight Center in Huntsville, AL, have leveraged space technology to invent an innovative knee brace for those recovering from strokes and knee injuries. Called the Selectively Lockable Knee Brace, the prototype device could mean quicker, less painful rehabilitation by allowing movement of the knee. Currently available knee braces lock the knee in a rigid, straight-leg position. In the new design, the upper part of the brace attaches around the thigh, with the lower part secured by a stirrup around the shoe. "It works by allowing the knee to bend when weight is not on the heel," explains co-inventor Neill Myers. "Once weight is placed on the heel, the brace locks into position." The device is a spin-off of mechanisms and materials technology used in developing propulsion systems at Marshall. The inventors are working with a private company to test the prototype and verify the design. For details, e-mail Dave Drachlis at [email protected].

Carbon nanotubes contain chemical reaction

A team of researchers from three institutions has carried out a chemical reaction in what may be the world's smallest set of test tubes: carbon nanotubes with inside diameters of less than 10 nanometers and lengths of just one micron. The work could ultimately have important applications in microelectronics and other fields where extremely small conductors and other structures would allow production of new types of nanoscale devices. Scientists from the Georgia Institute of Technology, the Laboratorio Nacional de Luz Sincotron in Brazil, and the Ecole Polytechnique Federale de Lausanne in Switzerland formed the carbon nanotubes, then opened the ends and allowed capillary action to fill them with molten silver nitrate. In the final step, they decomposed the silver nitrate into metallic silver by heating the tubes with a beam from an electron microscope. The process resulted in chains of tiny silver beads within many of the nanotubes, each bead separated by a pocket of gas under pressure as high as 1,300 atmospheres. Next, the team wants to use the process to produce a continuous metallic wire with a graphite sheath around it. The technique could also be used in flat-panel displays and to produce encapsulated compounds. For more information, visit

Diaphragm pacemaker could enable independent breathing

Surgeons at Penn State's Milton S. Hershey Medical Center recently implanted a medical device that may eventually allow the patient--a former high-school athlete--to breathe without a ventilator for the first time since a summer sports injury rendered him a quadriplegic. If the surgery proves successful, the patient's nerves will regenerate enough to use the implanted device--a tiny electrode and radio receiver with an implanted antenna. Doctors performed two nerve grafts during the six-hour surgery. After a few months, the implanted pacemaker's application of repetitive stimulus patterns to the phrenic nerves should result in smooth, rhythmic contractions of the diaphragm, thus allowing air into the lungs. Diaphragm pacing is far less expensive than using a mechanical ventilator. The technology also lets patients live outside of hospitals and nursing homes, eliminating the cost of inpatient care. Added benefits include: more normal breathing and speech, ease of eating and drinking, increased patient mobility, unobtrusiveness of the equipment, and silent operation. E-mail [email protected].

Satellite-based remote sensing to map Earth resources

Within two years, scientists hope to launch satellites that will let them produce the most complete maps of the composition and temperature of the Earth's surface. The data are essential in exploring for natural resources such as minerals and natural-gas deposits, monitoring global warming, or giving early warning of volcanic eruptions. The satellites, making up an Earth Observing System, will use remote sensing to gather data for studying the planet's surface and atmosphere. One of the goals is to make, for the first time, a worldwide map of the thermal radiation emitted from the planet's surface. John Salisbury, a research scientist at the Johns Hopkins Department of Earth and Planetary Sciences, pioneered the technique using an infrared spectrometer to learn what something is made of by analyzing the thermal radiation it emits. He is compiling a library of the spectral signatures of infrared radiation emitted by specific materials. These data will help scientists interpret the satellite data. FAX Johns Hopkins at (410) 516-5251.

Process yields durable, lightweight metal parts

A metals-forming process developed about 25 years ago by MIT scientists is now giving automobile components manufacturers a new way to produce highly durable, lightweight precision parts. The process, known as rheocasting, is taking off mainly because of new automotive industry requirements for long-life, reliable, and lightweight parts that cannot be met by the traditional forming process of die casting. MIT has licensed the process to Alumax Inc., St. Louis, which has used it primarily to make longer-lasting aluminum automotive components for suspensions and air conditioners. Rheocasting was discovered in 1971 by David Spencer, then a doctoral student in the lab of Professor Merton Flemings of MIT's department of materials science and engineering. Spencer found that agitation of a molten metal during solidification made it smooth and creamy when it was partly solid, like ice cream. It was immediately clear to researchers that this flowable semisolid material could be the basis of a wholly new metal-forming process. The original work was supported by the Office of Naval Research and the Army Research Office, subsequent work by the Advanced Research Projects Agency, and current work by the DOE and industry. E-mail Elizabeth Thomson at [email protected].

Modems go cordless

Operating on the same principle as cordless telephones, new cordless modem technology jointly developed by IBM and Panasonic allows users to go on-line without physically connecting to a phone jack. Instead, the data are transmitted directly between the PC and a small device connected to the jack. Because the technology requires no software, driver, or operating-system changes to PCs, it literally offers users "plug-and-play" convenience. Based on patent-pending technology originally developed at IBM Research, the cordless modem technology delivers V.34 connections at speeds up to 28.8 kbps using a modified radio architecture similar to that used in current 900-MHz cordless phones. By basing the technology on existing protocols, the two companies each anticipate developing products this year that support high-speed analog modem data rates at an affordable cost. E-mail [email protected] or [email protected].

Plans afoot to convert natural gas to diesel fuel

Exxon Corp. may build the oil industry's first plant to cost-effectively convert natural gas into liquid fuels such as diesel. The firm is in talks with Qatar's state-owned oil company to build such a plant--using Exxon's technology--supplied by oil fields too remote for natural-gas pipelines. Such liquid fuels are more easily transportable and are cleaner, too: Natural gas-produced diesel is of a higher quality than that produced from crude oil, and has no sulfur. When burned, it produces less carbon monoxide and hydrocarbon emissions. Tulsa, OK-based Syntroleum Corp. is working on a similar project. Visit

Prosthetic foot promises better balance

ATufts University bioengineer has developed a prosthetic foot that he says better mimics how a biological foot works. Besides helping amputees maintain their balance and stand, walk, or run more naturally, the new design decreases the pressure that can cause painful and dangerous wounds to the area where the prosthesis attaches to the leg. Current prosthetic feet are fairly good at shock absorption and propulsion, or "push off," says inventor Mark R. Pitkin, research assistant professor of bioengineering at Tufts School of Medicine. But a natural foot also provides balance and gait control using 33 complex joints, 26 bones, and more than 100 ligaments, muscles, and tendons. Pitkin analyzed the electrical impulses in biological feet and lower leg muscles during a stance--the part of a stride when all or part of the foot is on the ground. Using that data, he pinpointed and measured the moments of resistance in the ankle joint produced by muscle and tendon contractions. Pitkin noticed that the pattern of resistance was nonlinear and concave, with resistance almost nonexistent in the first part of the stance as the body leans forward and weight shifts from the heel to the ball of the foot. He then mapped the resistance patterns of the most popular prosthetic feet and discovered that they didn't match the physical reality of the gait. Pitkin's device, called a rolling-joint foot, allows for a progressive buildup of resistance in each stance. "The idea is the foot rolls along, producing resistance in a certain pattern," he says. For more information, e-mail [email protected].

Light-duty, long-range natural gas vehicle debuts

The nation's first long-range natural gas vehicle has hit the road. The "LongRanger" van, a working prototype developed by Long Beach, CA-based NGV/USA Inc., is a modified Chrysler Dodge Ram 350 van that achieves extended range by using a Multi-Fuel Storage Chassis. This chassis design incorporates cavities into the structure of the frame that allow natural gas cylinders to reside there, rather than attaching the cylinders as an afterthought. Two 62 x 14.8-inch cylinders are attached with steel hoop rings and brackets lengthwise within storage cavities located in the modified frame rails. The two existing smaller tanks remain perpendicular to them in the rear of the frame between the rear axle and bumper. The overall dimensions, suspension, and drive train of the Chrysler remain unaltered. Together, the cylinders hold 27 gasoline-gallons equivalent of compressed natural gas--enough for the vehicle to travel up to 340 miles before refueling. Previously, natural gas vehicles had been limited to a 150-mile range. Preliminary research indicates that when mass-produced, this adaptation can be cost effective and modified to accommodate other alternative fuels, such as propane, hydrogen, and even electricity. Interest in natural gas vehicles has increased over the last seven years due to governmental mandates and heightened concern for the environment--natural gas is about 30% cheaper and burns twice as clean as gasoline. FAX NCV/USA at (310) 595-0446

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