A Conoco worker sidesteps environmentally sensitive areas in northwestern New Mexico by using the company's new seismic cabling method.

First, Conoco applied software written by Input/Output Inc. of Houston in order to use many shorter cable segments, at most a quarter-mile in length, and spaced nearly a quarter-mile apart. Three-dimensional geophysical data picked up by the geophones is transmitted by remote radio signals. "We cut in half the total length of cable required for the seismic job," said Peter Eick, the senior geophysicist at Conoco who led the survey design project. "Most important, when we come to an area with endangered plants or animals, or a dangerous cliff or terrain, we can just stop right there, apply our remote radio link, and leapfrog that area before laying the next cable segment on the ground."

In 1998, Conoco used its new cabling method to reduce injuries to workers stringing cable over the steep cliffs in the San Juan natural gas basin of northwestern New Mexico. There were no recordable injuries due to cabling, according to Eick.

The new cabling technique also safeguarded the 34 plant and animal species that live in the 355-square-mile San Juan Basin, protected by state and federal authorities as threatened and endangered. Conoco and its contractor crews from Dawson Geophysical Co. discovered 30 previously unknown sites of rare plants, including Brack's cactus and Aztec gilia, which they avoided by using the new cabling layout method. Conoco employees mapped all the newly discovered sites and shared the information with the Bureau of Land Management in Farmington, N.M.

The mobile radar cross section measurement system at Holloman Air Force Base was designed in response to stealth technology.

The project involved upgrading a fixed-site facility, and providing a mobile system that is almost identical to the fixed system, according to Ted L. Lane, principal scientist for the project at the Research Institute. "The mobile system can be moved around on the range, allowing the Air Force to do bistatic as well as monostatic tests," Lane said.

A monostatic system has the transmitter and receiver in the same location. The reflected, or backscatter, signal must return to the receiver by a direct path. Stealth design includes faceted plates, which deflect the backscatter signal away from its point of origin.

A bistatic system separates the transmitter and receiver. The reflected signal is called forward scatter. It travels from the transmitter, hits the target, and goes to the receiver, forming a bistatic angle.

The upgraded radar includes a stationary unit and a mobile unit. Either unit can be used in the monostatic mode. Or the two units can be used together in a bistatic mode, in which one is used as a transmitter and the other as a receiver. In the bistatic mode, the mobile system can be positioned at different bistatic angles around the target, looking for vulnerabilities.

The new mobile unit—which is 40 feet tall, 66 feet long, 37 feet wide, and weighs 90 tons—was built at the Georgia Tech research facility, disassembled and shipped to the U.S. Air Force's 46th Test Group, Radar Test Scattering Division, where it was reassembled last summer.

The two radar systems are linked together using fiber optics for bistatic measurements, but can also operate independently to provide high-speed, simultaneous measurements. Operating together, the two systems can simultaneously produce bistatic and monostatic data from each radar unit.

Georgia Tech researchers designed and supervised construction of the transportable unit. On the mobile system, eight radar dishes, ranging in diameter from 14 inches to 10 feet, illuminate targets up to 80 feet in length at typical ranges of 5,600 feet. On the fixed system, the mobile dishes are duplicated, along with a 160-foot dish. On both systems, the antenna positions are computer controlled.

Pollak Actuator Products greatly reduced its inspection cycle by switching from mechanical measuring and outsourcing to a CNC coordinate measuring machine.

To speed up the inspection process and to bring it all in-house, the company decided to upgrade to numerically controlled coordinate measuring for pre- and post-inspection. After evaluating several models, the company settled on a Mitutoyo Bright 504 CNC coordinate measuring machine, supplied by MTI Corp. of Aurora, Ill. Factors that tipped the scale in its favor were reverse engineering capability, scope of operating software, and future software upgrades, according to David Capucci, quality systems team leader.

Inspection time of a complex adjunct door lock actuator housing was reduced from weeks to minutes. Shaped like a pistol handle, the part measures 4 x 3 x 0.5 inches, and has 76 features to measure on two sides. Critical features include hole diameters and depths, angles, positions, geometric tolerances, linear distances, straightness, and thickness. Previously, the company outsourced the component for pre-inspection. The outside vendor took two weeks just to set up the program and four weeks to send the inspection results back to Pollak, which now performs the inspection in-house, in just five minutes. The inspectors also have the time to perform higher-level inspection as well as reverse engineering work that wasn't possible before.

It took from six to eight months of training before inspectors felt proficient enough to perform complex measurements. Inspectors now write macros for the part using general-purpose GEOMeasure software, also from MTI Corp. A joystick facilitates component verification and creation of part programs. As the user performs the inspection steps in "learn" mode, the steps are recorded in memory for future play. The inspector calls up the part program and presses the "run" button. The coordinate measuring machine's probe scans the part in a single setup, compares it to the part program, and gives a "pass/fail" result and diagnostics.

A technician oversees the refining of ingots in the smaller electron beam furnace used for research purposes by Reading Alloys.

The two furnaces at Reading Alloys operate independently. The main furnace is a 400-kW hearth melt installation that can cast ingots up to 10 inches in diameter and 4 feet in length from solid or loose feedstock. This output is aimed at powdered metal or electronic components.

The second, smaller furnace is a 120-kW unit with both hearth melt and drip cast capabilities that can cast ingots from 1 to 4 inches in diameter, up to 18 inches long. Reading Alloys will use the smaller furnace for research and development purposes, such as evaluating new alloy combinations, and devising process improvements for larger ingot production in the main electron beam furnace for commercial applications.

Scientists in a lab at Georgia Institute of Technology in Atlanta have been studying carbon tubes with diameters measured in nanometers. Studies of these nanotubes have shown that electrical voltage can be used to induce electrostatic deflection and vibrational resonance in individual carbon nanotubes. This ability to selectively deflect or induce resonance in individual nanotubes opens new potential micromechanical applications.

The researchers studied the behavior of multiwalled nanotubes using a transmission electron microscope with a sample holder designed and built by Philippe Poncharal, a Georgia Tech professor. The holder allowed researchers to rotate specimens, apply electrical voltage, and observe many fundamental effects. The U.S. National Science Foundation and the U.S. Army Research Office helped fund the project.

"We can bend a nanotube almost 90 degrees, and it will still recover and straighten out," said Z.L. Wang, a professor at Georgia Tech's School of Materials Science and Engineering. "You can keep on bending them and they will not break. This shows that although nanotubes are very rigid, they have an extremely high elastic limit. Very few materials can do this without damage."

Each nanotube resonates at a specific frequency that depends on its length, diameter, density, and elastic properties. "You can select which one you want to examine and make it resonate," Poncharal explained. "Then you turn up the frequency and another one will resonate."

The resonance occurs in a very narrow range, allowing the researchers to measure the damping properties of the nanotubes. "These resonances were very narrow, so finding them was like tuning for an unknown radio station. You just keep looking," said Walter de Heer, a professor at Georgia Tech's School of Physics.

Using a particularly strong electron microscope, Daniel Ugarte of the Laboratorio National de Luz Sincotron in Brazil observed a rippling on the surface of thick nanotubes as they deflected. This confirms that bending in these tubes is different.

"The elastic constant varies as a function of its diameter, which is unexpected for a general material. This elastic constant should be an intrinsic property of the tubes, rather than depending on its geometry or size," explained Wang.

Using the tiny tubes as a nanobalance depends on the ability to calculate changes in the resonant frequency that occur with placement of an object onto a nanotube.

"This is comparable to putting an object on the end of a spring and oscillating it," said de Heer. "By knowing the properties of the spring, you can measure the mass of the object. We can use the nanotube like a standard calibrated spring."

Applying this technique, the researchers were able to find that a graphite particle attached to the end of a resonating nanotube had a mass of about 22 x 1015 grams. "There is no other way to accurately weigh something that small," he noted.

Foster Wheeler Energia Oy, the Finnish subsidiary of Foster Wheeler Corp., headquartered in Clinton, N.J., will design and manufacture a circulating fluidized-bed boiler for the Taiwan Cogeneration Corp. plant in Taipei. The 138-MW boiler will be fueled primarily by coal, but will also burn scrapped automobile tires and sludge to reduce wastes on the island nation. The nearly $13 million project is scheduled for completion by the end of 2000.

Raytheon Engineers & Constructors in Cambridge, Mass., has received a $52 million contract to design and install a coal pulverization plant to fuel Bethlehem Steel Corp.'s facility in Sparrows Point, Md. The pulverized coal injection system is expected to lower fuel costs and reduce the use of metallurgical grade coke in the production of iron at the 10,000-ton-per-day plant.

Florence, Italy-based GE-Nuovo Pignone will supply 17 turbocompressors for a new, 1,900-mile pipeline that will carry natural gas from western Canada to Chicago for distribution throughout North America. The compressors will transport an initial volume of 1.3 billion cubic feet of natural gas per day to meet the growing demand for the fuel.

American Superconductor Corp. has shipped its power quality equipment implementing superconducting wire to a paper mill in South Africa and to an Austrian electric utility.

Advanced Refractory Technologies Inc., the Buffalo, N.Y., nonoxide ceramic materials manufacturer, has opened satellite offices in Warren, Mich., Washington, and Phoenix.

home | features | news update | marketplace | departments | about ME | back issues | ASME | site search

© 1999 by The American Society of Mechanical Engineers