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Fish-Friendly Turbine * Power Plant on a Chip * Fortunate Timing * Plasma for Textiles * Coal Mining on Display * It's All in the Bubbles

Fish-Friendly Turbine
When hydroelectric power plant officials sought a way to minimize the number of fish killed or injured by generator turbine blades, two Massachusetts companies came to the rescue, according to a report in Engineering Times magazine. With the help of the Department of Energy, the Alden Research Laboratory in Holden and Concepts NREC in Woburn have designed a prototype turbine with only three blades, which are longer than traditional blades and wrapped in corkscrew fashion around a central hub. This geometry results in lower pressure and reduces sudden changes in flow velocity, yielding a safer environment for fish.

With conventional turbines, typically between 5% and 10% of fish passing through a generation facility get killed. Until now, the only way to minimize fish mortality was to divert water around plants, which reduced injury to fish but also reduced energy production. The new turbine's efficiency is predicted to be only a few percentage points lower than conventional turbines, and the cost should be equivalent to other turbines.

Testing of the new turbine is taking place at a specially-designed facility that includes a 24,000-gallon fish collection tank and will be done using many varieties of fish, including rainbow trout, bass, shiner, eel, salmon, shad. sturgeon, and sucker.

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Power Plant on a Chip
Scientists at Lehigh University are developing a tiny generating plant on a silicon chip that they believe can produce enough hydrogen to run portable electronic devices. "About 10 years ago, people starting asking, 'Can we take the same fabrication methods for silicon chips and instead of using them for electronics, use them for something else?'" says Mayuresh Kothare, assistant professor of chemical engineering. Instead of a processing device for electrons, chips will become miniature chemical reactors or power plants, he says. Funding for Kothare's projects comes from the National Science Foundation (NSF), Sandia National Lab, and the Pittsburgh Digital Greenhouse, a consortium of electronics companies.

"At Lehigh our chip-based micro-chemical plant will take a reagent, such as methanol, or a hydrocarbon, like diesel or gasoline, and carry it to a tiny reactor to produce hydrogen," Kothare explains. "We have already produced hydrogen and have been able to get the reagents into the reactor to carry out the necessary reaction." The hydrogen will be collected in a miniature fuel cell that can power an electronic device. A fuel cell creates power through the electrochemical reaction between hydrogen and oxygen.

The chip is the same size as an ordinary electronic chip, about three by three centimeters. The micro-plant would be fueled by small cartridges of methanol or other hydrocarbons fed to a reformer by micro-capillaries or miniature fuel lines. Electricity would heat the reformer, and the reaction would produce hydrogen to be transmitted to the fuel cell via another network of micro capillaries.

While one chip couldn't produce enough power to operate, say, a laptop computer, Kothare says that by wrapping hundreds of the tiny micro-plants together ­ called numbering up ­ enough power could be produced to operate all kinds of electronic devices. In a recent experiment in Germany, a hydrogen micro-fuel cell powered a laptop computer for up to ten hours, whereas the operating time of an ordinary rechargeable laptop battery is typically about two hours.

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Fortunate Timing
When terrorist-hijacked American Airlines Flight 77 slammed into the western face of the Pentagon in Washington, D.C. on September 11, 2001, it penetrated the first and second floors of Wedge 1. Luckily, casualties and damage were minimized by improvements made in the first phase of a building-wide renovation project begun in 1993. The explosion and fireball that resulted were impeded by a recently-installed sprinkler system. And a portion of the building at the point of impact withstood collapse for nearly 35 minutes thanks to new reinforced structural steel and blast-resistant windows, allowing thousands of people in the area to escape.

Although the loss of life was tragic, "the Pentagon performed magnificently. Our building was hit by a Boeing 757 loaded with 20,000 gallons of jet fuel and traveling at 350 miles an hour," says Lee Evey, program manager of the Pentagon Renovation Program. "Yet, only 125 Pentagon personnel of the 2600 people in the vicinity were killed."

Wedge 1 had just undergone a three-year renovation that brought nearly one million square feet of office space to its core and shell, allowing for the abatement of hazardous materials and reconstruction and installation of utilities. Installation of new sprinkler, ventilation, and lighting systems followed. The Pentagon, headquarters for the Department of Defense, had never undergone a major renovation in its 60-year existence.

Installed on the outer ring of Wedge 1, the blast-resistant windows weigh 1600 pounds apiece and have glass an inch-and-a-half thick. They sit within a web matrix of reinforced structural steel bolted to the slabs of each of the five floors. Stretched between the reinforced structure is a Kevlar-like geotechnical mesh designed to keep debris away from personnel inside the building in the event of an exterior explosion. New windows on the third and fourth floors, adjacent to the area that eventually collapsed, remained intact, while old windows in the not-yet-renovated Wedge 2 blew out.

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Plasma for Textiles
Permanent press shirts. Flame retardant sleepwear for children. Stain-resistant furniture fabrics. We take all these products for granted as well as the textile technology that makes them possible. These convenient and safe products come at a price, however. The wet fabric finishing processes used to create them produce polluting effluents and consume large amounts of energy in drying.

An interdisciplinary team of scientists at North Carolina State University is conducting research that could change the way fabrics are processed. Using facilities in the departments of nuclear engineering, textile engineering, and chemistry and science, the team is testing atmospheric plasma for fabric finishing treatments. According to Mohamed Bourham, professor of nuclear engineering, plasma is an ionized state of gas that can be used for a variety of applications. It's easy to generate plasmas under vacuum conditions, but creating them in normal atmosphere proves more difficult, as it requires very high voltage. "Now, using a technique of oscillating electrical fields, atmospheric plasmas can be generated using a reasonable voltage," says Bourham.

Plasma processing has several advantages over traditional wet fabric treatment. Soil resistant, flame retardant, dye, and permanent press treatments can all be accomplished without creating toxic effluents. Atmospheric plasma treatments can be integrated into the production manufacturing process, reducing pollution and energy consumption. Plasma treatment modifies the fiber surface rather than its interior, which allows the fabric to retain strength. According to Marion McCord, assistant professor of textile engineering, chemistry and science, "Surface treatments such as plasma are important because we want to achieve changes in surface properties without degrading the mechanical properties of the material." He adds, "Right now, we can enhance wet chemical processes by pretreatment with plasma. The long-term goal of the project is eventually to replace wet processes with methods such as plasma treatment."

Bourham, McCord, and their colleagues hope to extend the current program into an atmospheric plasma center to take advantage of this expertise at NC State. To this end, they are seeking new alliances with industry. Current funding for the project comes from the National Textile Center, Cotton Incorporated, PPG Industries, and the U.S. Department of Agriculture.

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Coal Mining on Display
A two-year project to process 1000-plus boxes of Coxe Mining Company records is complete, and the collection has officially entered the public domain, says an Associated Press report. In the anthracite region of northeast Pennsylvania, the Coxe family oversaw the largest family-owned coal-mining operation in the country. Mostly during a heyday from 1865 to 1905, the Coxe Mining Company owned 30,000 acres of land along with mining operations, company towns, and even their own railroad, and they once employed 2000 people.

Grants from groups such as the National Historical Publications and Records Commission made it possible to organize, inventory, and store the huge collection of documents, photographs, and maps. Officials say this will prove invaluable to researchers of labor, engineering, business, and northeastern Pennsylvania history.

An engineer with 111 patents to his credit, Eckley Coxe was the best known of the Coxe coal barons. He invented equipment that modernized mining and turned his family's land holdings into a coal empire. In 1879, he founded the Mining and Mechanical Institute (now the MMI Preparatory School) as a night school to teach miners basic math, science, and English. He did this to make technical training available in the U.S., as he often had to go to Europe for the knowledge he needed.

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It's All in the Bubbles
An engineering graduate student at Virginia Tech has made drinking water treatment discoveries that have caught the attention of the treatment industry and may help prevent water-borne diseases. Paolo Scardina, a Ph.D. candidate in the civil and environmental engineering (CEE) department, began his research as an undergraduate on the problem of air bubbles in drinking water. Working with Marc Edwards of the CEE faculty, Scardina has continued his research through his master's and into his doctoral program, and he recently won a $150,000 grant from the American Water Works Association Research Foundation.

Why would ordinary air bubbles, which occur naturally in water, cause concern in drinking water treatment? "When you open a can of soda, bubbles form and rise to the surface," explains Edwards. "The same thing can happen in water from lakes and rivers. When air bubbles are released in a burp during treatment, pathogens and other particles can escape removal." The last treatment barrier in most drinking water treatment plants is filtration, Edwards says, and a burp of bubbles can punch holes in filters-tiny holes, but large enough to let particles and pathogens escape into the water that goes to customers. "Air bubbles in water have never been studied in terms of their ability to affect treatment processes."

In studying why bubbles form and how they punch holes in treatment plant filters, Scardina has discovered that air bubbles can interfere with the first drinking water treatment process-settling-where solid particles from incoming surface water drop to the bottom of treatment tanks. "If bubbles are present at this stage," Scardina notes, "pathogens and other particles can attach to them and float on through the treatment plant."

Last year, the Mendocino District Office of the California Department of Health Services flew Scardina to the west coast to help engineers identify the source of air bubble eruptions occurring at two water treatment plants. "Paolo is doing some very important work," says Guy Schott, associate sanitary engineer for the Mendocino District. "Paolo's research has given us a good understanding of the sources of our problems," Schott notes. "He's the only person I've found in the U.S. who does work in the field of dissolved gases and their impact on treatment."

In the plants Schott and Scardina have investigated, air bubble eruptions have carried solid particles into the filtration process, which leaves the treatment systems open to pathogen contamination. Schott is concerned about the potential for outbreaks of viruses, as well as Giardia and Cryptosporidium, both microscopic parasites that can cause severe gastrointestinal illness (a major water-borne outbreak of Cryptosporidium in Milwaukee in 1993 caused illness in an estimated 403,000 people). These parasites are impervious to chlorine disinfection, so they must be removed through settling or filtration.

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Progressive Engineer
Editor: Tom Gibson
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©2004 Progressive Engineer