You are browsing the archives of glass fiber.

According to an ORNL press release, by adapting conventional glass fiber drawing technology to process carbon nanotubes into multichannel assemblies, researchers believe they have the potential to mimic the human nervous system.

“Our goal is to use our discovery to mimic nature’s design using artificial sensors to effectively restore a person’s ability to sense objects and temperatures,” says Ilia Ivanov, a researcher in the Center for Nanophase Materials Sciences Division.

The ultimate goal is to duplicate the function of a living system by combining the existing technology of glass fiber drawing with the multifunctionality of submicron (0.4 micron) scale carbon nanotubes, according to Ivanov, who described the process.

“We make this material in a way similar to what you may have done in high school when making a glass capillary over a Bunsen burner,” Ivanovsays . “There, you would take the glass tube, heat it up and pull, or draw, as soon as the glass became soft.”

Ivanov and John Simpson of the Measurement Science and Systems Engineering Division are doing something similar except they use thousands of glass tubes filled with carbon nanotube powder. After several draw cycles, they demonstrated that they could make fibers just four times thicker than a human hair containing 19,600 submicron channels with each channel filled with conducting carbon. Each carbon nanotube-containing channel is electrically insulated from its neighbors by glass so it can be used as an individual communication channel.

This multichannel composite has many other potential uses, including in aeronautics and space applications, where low weight of conducting wires is important. The next steps are to make these channels highly conductive and then show sensor communication through individual channels.

Share

Credit: University of Maine AEWC

The New York Times has a report on a candidate for the ‘bridge of the future” title: the Neal Bridge in Pittsfield, Maine, that has a foundation of 23 hollow carbon- and glass-fiber fabric arches, filled with concrete. These are 12-inch-diameter tubes that have been inflated, bent to the proper shape and stiffened with a plastic resin. They are then installed side-by-side and stuffed with concrete, “like giant manicotti.” Covered with composite decking and compacted soil, the arches support a standard gravel-and-asphalt roadway.

Fiber-reinforced plastic strips and sheets have been used in the past to repair concrete or steel on existing bridges, or to strengthen structures against earthquakes. Glass-fiber rods have replaced steel in some reinforced concrete work, because corrosion of steel rebar from road de-icing chemicals destroys concrete.

Others have been demonstrated that use a “hybrid composite beam” technology that looks somewhat similar to traditional bridge girders.

John Hillman, an engineer and president of HC Bridge Company in Wilmette, Ill., has developed straight beams that combine polymers with concrete and steel. The basic beam consists of a rectangular FRP tube with an arch-shaped conduit formed inside it. The conduit is filled with concrete, which provides compressive strength, and steel rods along the bottom of the tube provide tensile strength. The beams have been used on a test railroad bridge in Colorado and several road bridges in Illinois and New Jersey.

“Everything about the beam is designed to be compatible with conventional means of construction,” said Mr. Hillman, who has been working on the design for 14 years. “We’re very close right now to parity with concrete and steel on an installed-cost basis.”

The Neal Bridge design, however, is a departure from these hybrid girder construction and uses little of the relatively costly-FRP material. The FRP it does use serves largely as a shell for the less-expensive concrete. The tubes help protect the concrete from de-icing chemicals, potentially reducing maintenance costs. Also, no internal rebar is needed.

The technology behind the tube-bridge structure is a product of the University of Maine’s Advanced Engineered Wood Composite Center. A spinoff comany, Advanced Infrastructure Technologies, is working to develop and commercialize applications for what has been dubbed “bridge-in-a-backpack” technology.

In an interview earlier this year with the Bangor Daily News, AEWC director Habib Dagher said, “This is a milestone because of how exciting this technology is. It has the potential to change everything in terms of bridge construction. It can change the way bridges are built in the future.”

AIT plans to continue to work with HC Bridge, and Maine officials said the endeavor could create about 100 new jobs and lead to at least six new bridges in Maine over the next several years.

The bridge in Maine has been standing for nearly one year, and cost less than $600,000 to build.

Share