The German firm Tacke Windtechnik, for example, built the first of what is believed to be the world's largest wind turbine, capable of generating 1,500 kilowatts each, near Emden, Germany. The turbine's blades are 105 feet long and measure 6.5 feet wide at their base, but weigh only 3,000 kilograms each because they are made of a composite carbon fiber molded by the French company ATV at its Douai factory. The composite was originally developed to reduce the weight of aircraft parts, and is only half the weight of wood, polyester, or glass fiber used to make wind-turbine blades.

A second 1,500-kilowatt Windtechnik turbine is being constructed at the port of Dunkerque in northern France, with a 200-foot mast. Nearby, a field of nine 300-kilowatt wind turbines is being erected. The turbines' 72-foot masts are made of folded steel to provide strength and electroplated with zinc to protect them from salt-air corrosion. The masts were made by Petitjean, a manufacturer in Troyes, France, that specializes in fabricating tall masts and pylons for the utility industry.

A key component of the Dunkerque wind turbines is the speed gear that transmits the power from the rotor to the generator, stepping it up from 40 rpm to 1,500. These gears were made by CMD Engrenages et Reducteurs in Cambrai, France, based on the company's armaments work.

Construction Electrique de Beaucourt, a major electrical parts manufacturer based in Beaucourt, France, designed and built the electrical generators for the wind turbines using its technique for shielding the motor windings from vibration. This technique involves impregnating the windings with resin, then coating them with epoxy.

The steel and aluminum robot arm enables its operator to lift a weapon of up to 5,000 pounds but feel a weight of just 10 pounds, according to Francois G. Pin, a senior research scientist at the Oak Ridge National Laboratory in Oak Ridge, Tenn., where the handler was developed. The hydraulic system can then position the payload using very precise submillimeter incremental accuracy.

The operator moves a handle on the arm's end effector to control direction; the robot itself coordinates joint motion so obstacles are avoided. The arm also feeds forces that act on the weapons gripper back to the operator, who would then feel the bomb payload contacting a wall, for example, and cease further motion.

The major control behind operation is known as man amplification, which multiplies the forces from the operator by up to a 1:500 ratio into the strength required for a task. Many of the handler's control technologies, such as a new control theory for hydraulic actuators, are still waiting for patents, Pin said. "It uses the same principles as exoskeletons," he added, "except here the robot doesn't surround the operator's body but is next to the body."

Propelled by a 70-horsepower diesel engine, the munitions handler sits atop a completely omnidirectional wheeled platform that can move in all directions and rotate simultaneously. Speeds of up to 1 foot per second, which is fast for this type of device, are possible with the platform.

Once in operation--tests should end sometime this summer, Pin noted--the robot will reduce loading crews from three members each to two, saving approximately $40 million per year. Eventually, the munitions handler may be adapted for other tasks in the private sector that involve heavy payloads and precise positioning, such as in automotive assembly.

A miniature pump that can be implanted into the human body will be able to monitor and control the flow of a drug entering the system to ensure a patient's health as it saves expensive medicine.

Developed at Case Western Reserve University in Cleveland, the drug pump is a microelectromechanical system (MEMS) that merges actuators, sensors, electronics, and a power supply on a silicon wafer approximately three times the width of a watch's nickel-cadmium battery. MEMS technology will keep the closed-loop system small enough to eventually be placed in a patient's body through a minimally invasive surgical procedure, and batch fabrication will be able to produce the pump at a lower cost than is possible with today's delivery systems.

According to Michael Huff, a professor at Case Western who helped develop the device, the pump will be able to check flow more accurately than previous systems, which is very important with today's more-powerful--and more-expensive--drugs. Huff added that, with patients leaving hospitals sooner, delivery systems are "moving toward ambulatory applications or implantable systems, but they must be safe and smart. MEMS enables us to develop that."

Most actuators for a pump this small--1.4 square centimeters and 2 to 3 millimeters thick--cannot generate enough force or displacement to maintain fluid flow, Huff said. In the new design, a titanium-nickel shape-memory alloy, which changes shape when heated to 60¡F and returns to normal when cooled, provides 10 to 100 times more force than bimetallic and other MEMS actuators.

The pump's spring is a silicon cylinder surrounded by two layers of the alloy. The layers are heated alternately, thus changing shape to create cyclical motion in the pump. Joule heating requires just 0.25 watt; eventually, that can be reduced to 2.5 milliwatts, Huff said. Polyimide check valves control flow direction and enable the pump to move up to 60 microliters of fluid per minute.

Closed-loop control is achieved by a sensor that measures how a drug is flowing into the body. That information is sent to the microelectronics that direct power output to coordinate dosages. A similar concept could enable diabetics to measure and maintain the levels of insulin in their bloodstreams. Instead of a flow sensor, Huff said, optical systems would be used to detect how fast glucose is absorbed in tissue. The Food and Drug Administration is currently evaluating this type of technology.

The prototype drug pump is being bench-tested to optimize thermal response and to fully understand the alloy's fatigue properties. "We've taken it up to 100,000 cycles, about a few months of pumping," Huff said, "but we need to take it to millions to solve fatigue questions conclusively."

General Motors Corp. in Detroit is planning to build a prototype series-hybrid electric vehicle that will include a small turbine engine.

In a series hybrid, the conventional powertrain is replaced with an electric motor powered by batteries, coupled with an auxiliary power unit (APU) powered by hydrocarbon fuel. Because a series hybrid can function solely as an electric car for a limited range, the vehicle can have zero emissions. The series-hybrid approach also addresses the limited cruise range of current electric cars because it can operate on both electric and fuel-generated power.

The car maker is working with Williams International in Walled Lake, Mich., to develop the turbine auxiliary power unit, which GM chairman John F. Smith, Jr., said is "the smallest, lightest, most fuel-efficient APU of its kind ever built." The new turbine has the potential to provide anywhere from a 50-percent boost in fuel economy to even greater levels, depending on how it is used in daily application.

The turbine APU, which will power a generator, will run only when required. "The turbine APU can run on just about anything that burns," said G. Richard Wagoner, Jr., president of GM's North American Operations. The power plant features a heat-recovery unit that increases efficiency and acts as a "muffler" to reduce noise.

SatCon Technology Corp. in Cambridge, Mass., is developing a power controller for the hybrid electric prototype. The controller will start the turbine engine and control the power transfer from the turbine to the battery.

"The goal is to perfect this technology by early in the next century," Wagoner said.

The smaller system will consist of the IImorrow Global Positioning System and a receiver set at 1,090 megahertz to capture the GPS squitter signals transmitted by other aircraft in flight to identify their positions. An AlliedSignal Mode S transponder will receive and decode the traffic-information-system uplink data transmitted by ground radar stations. A computer will combine the data from both sources to display the bearings and range of nearby aircraft, their relative velocity, and the relative altitude rate on a screen mounted in the cockpit.

While relying on standard equipment, the Michigan Technological engineers are customizing hardware and software for this application. "We are modifying the transponder to communicate with the anticollision system's computer," said project leader Jeff Burl, assistant professor of electrical engineering at the university. "We are also upgrading the receiver's decoder logic by putting it on a single chip, making the unit more compact." Burl and his colleagues are using Kalman tracking filters to develop software that will enable the system computer to track targets, calculate the possibility of collision, and retrieve information.

"We expect to lab-demonstrate a prototype by November, and we will have it in an airplane for tests by next spring," Burl said. Each system costs about $100,000, but he added that they are working on a version that will cost about $3,000, within the reach of small-plane owners. The project is being funded by a two-year, $90,000 grant from the Federal Aviation Administration.

The U.S. Department of Energy (DOE) and the Office of Science and Technology announced a new technology deployment initiative (TDI) to help DOE sites deploy technologies that can accelerate site cleanup, reduce remediation costs, and be used at multiple sites. DOE has issued a call for technology proposals for the TDI, which is being managed by the department's Idaho Operations Office. n A new scale of measuring force has been achieved by scientists from Stanford University in Stanford, Calif., and the IBM Almaden Research Center in San Jose, Calif., using an ultrasensitive cantilever they are developing. This device is 1,000 times as fine as a human hair and is designed to measure atto-newton forces, which are barely enough to lift a single protein molecule. The cantilever will be incorporated in a magnetic-resonance-force microscope, also under development, to permit the study electronic materials on the atomic level.

Engineers at the Southwest Research Institute (SWRI) in San Antonio, Tex., have launched two cooperative research programs to reduce automotive emissions. A one-year project will examine the effect of the higher vibration and higher temperatures catalytic converters are subject to because they are mounted closer to auto engines. SWRI has also started a five-year effort to develop technology for an equivalent zero-emission vehicle using a conventional engine and powertrain, rather than the conventional approach of electric batteries.

AstroPower Inc. in Newark, Del., has developed a 16.6-percent-efficient silicon-film solar cell, breaking the previously established record of 14.6 percent, as part of a U.S. Department of Energy program to reduce the cost of photovoltaic systems. AstroPower credits an increase in short-circuit current for the new solar cell's improved performance.

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© 1997 by The American Society of Mechanical Engineers