North Carolina State University News Services Campus Box 7504 Raleigh, NC 27695 (919) 515-3470
November 13, 1997
NC State News Tips A roundup of NC State University research and outreach activities. For use by the media as briefs or as background for stories.
Media Contact: Tim Lucas, News Services, 919/515-3470 or [email protected]
A Smarter Way to Kill Weeds -- Each year, crews spray millions of gallons of herbicide along roads and power lines to kill weeds. But dense groundcover or rough terrain can cause spotty coverage, and chemical runoff can harm the environment. Now, NC State scientists have come up with a better way. Drs. Jim Burton and Walter Skroch have made an herbicide applicator that can be attached to weed mowers. It applies a thin film of chemicals directly to plant stems as they're cut. Tests show that up to 90 percent of the herbicide applied this way is directly absorbed into the plants. None ends up on the ground, reducing the risk of runoff. And since the chemical is never sprayed into the air, it's safer for workers, too. Burton and Skroch worked with Burch Inc. of Wilkesboro, N.C., to create the applicator. A model for use on home lawnmowers is being developed.
Software Offers An ëAnimated' Guide to the Internet -- Schools today are expected to teach K-12 students about computers and the Internet. But many lack the resources to give kids the one-on-one instruction needed to master the technology. "Cosmo the Internet Adviser," a new interactive software program developed at NC State, can help. Part computer game, part personal tutorial, it combines eye-popping animation with artificial intelligence to take kids on a fantastic voyage into the guts of a computer and onto the Internet.
"With Cosmo, students can have a virtual tutor -- an intelligent, animated character who gives personalized lessons about the Internet on demand," says Dr. James Lester, an NC State computer scientist. The program's artificial intelligence lets it react to and remember students' answers, and adjust the "game" to their skill levels. "Students learn at their own pace," says program designer Patrick FitzGerald. "And because it's fun, they end up learning more."
Closing in on a Fish Killer -- Since 1991, Pfiesteria piscicida has killed millions of fish and been linked to human illnesses in Mid-Atlantic waters. Efforts to control the organism have been hampered by scientists' inability to identify its toxins. Now, they're closing in. In August, scientists from NC State, the National Institute of Environmental Health Sciences and the National Marines Fisheries Service, successfully isolated Pfiesteria's main toxin. Next up: Identifying its chemical structure.
"Knowing the structure will let us devise tests to detect the toxin and find treatments for it," says NC State's Dr. JoAnn Burkholder, author of 17 scientific papers on Pfiesteria. Her most recent findings suggest there's no time to waste: In purified form, Pfiesteria's toxin can be heated to 170 degrees Fahrenheit for two hours without losing potency, and it can kill fish in three minutes.
The Disappearing Shore -- Thousands of homes and structures each year are lost to coastal erosion. NC State geologist Dr. Tom Drake can't stop the erosion. But, using data from a monthlong underwater experiment, he hopes to give coastal communities something almost as good: A way to predict where and when erosion will most likely take place.
Drake is making sidescan sonar readings of the nearshore ocean floor at Duck, N.C. The sonar images he collects will offer scientists the most detailed picture yet of the nearshore sea floor, showing the complex patterns of underwater dunes, sand bars and other features found there. By charting the movements of these features -- which help protect beaches from erosion -- and by identifying recurring patterns of movement, Drake hopes to devise a way to predict the probability of erosion occuring at any given site. "That information could be used by authorities to decide how close to the beachfront they allow development," he says.
Clean and Green -- Most dry cleaners use a toxic solvent called perchloroethylene, or "perc," to clean clothes. Now, they and their customers have a better choice. NC State chemical engineer Dr. Joseph DeSimone has developed the world's first nontoxic, recyclable, carbon-dioxide-compatible dry cleaning detergents. Unlike perc, which has been linked to human and environmental health problems, DeSimone's detergents are ecologically sound and give off no toxic fumes. Tests show they clean many fabrics -- including leather and suede -- better than perc.
The detergents are marketed by MiCell Technologies Inc., a startup company located at NC State. Similar detergents are being developed for industrial uses, such as cleaning machinery and precision parts. "Our aim is to make ëgreen' detergents to replace the more than 30 billion pounds of noxious solvents used each year as cleaning agents," says DeSimone.
New Electronic Nose is Nothing to Sniff at -- Engineers at NC State have developed an electronic nose capable of detecting and analyzing a wide array of smells, from the acrid odor given off by livestock waste, to subtle scents associated with food and beverages.
Lead researcher Dr. Troy Nagle says the device -- officially called a "gas sensor array test bed" -- is patterned after the odor-sensing capabilities of the human body. A pump, acting like the lungs, sucks in air from a small plastic bag containing a paper filter saturated with an odor. The smell is conducted by a plastic tube to the noselike electronic sensors, which send information about the properties of the odor to the device's computer "brain." The computer displays each odor's unique pattern on a colorful bar chart -- allowing human interpreters to diagnose what the specific odor is. The device could be used for monitoring air quality near large livestock farms or in industries where noxious or toxic gasses are a problem.
Kudzu Meets Its Match -- When the vine kudzu was brought to America from Japan more than 50 years ago, horticulturists envisioned it as a low-maintenance groundcover for steep slopes. Today, the rampant pest, which can grow up to a foot a day, covers 7 million acres of land in the South. Nothing short of massive, repeated doses of nonselective herbicides, which kill every plant in the treated area, has been shown to slow its inexorable march.
But NC State entomologist Dr. David Orr has found an environmentally sound way to curb the vine's spread. He uses a common bug -- actually two bugs eating in tandem -- to defoliate and kill it. "We take soybean looper caterpillar larvae and inject them with the larvae of stingless wasps," he explains. "The caterpillars eat the kudzu. Then the wasps inside the caterpillars hatch and eat the caterpillars from within, killing them before they can pupate into moths and eat nearby crops." As a bonus, Orr has found that caterpillars injected with wasp larvae eat nearly twice as much as normal, "which is good for us," he says, "but terrible for the kudzu."
Putting the Brakes on Pathfinder -- When NASA's Pathfinder spacecraft landed on Mars earlier this year, it used a technology called aerobraking -- literally, using the air as a brake -- developed in part at NC State's Mars Mission Research Center. For several years, aerospace engineer Dr. Ndaona Chokani and his colleagues at the center have used wind tunnels and computer simulations to learn how aerobraking works. Their research data helped NASA design a heat shield for Pathfinder that struck the right balance between drag and aerodynamics. "Too much drag and the craft would have burned to a crisp; too little air resistance and it would have crashed violently into the planet," Chokani says.
Previously, NASA spacecraft had relied on their jet engines to decelerate and land, a process that ate up huge quantities of precious fuel. "With aerobraking, you need to carry less fuel, so you can design spacecraft that is lighter, faster and more maneuverable," Chokani says. "Those are important qualities when you're traveling to Mars or beyond."
Birth Control, Before ëThe Pill' -- The desire for effective family planning is as old as Eve herself, says NC State historian Dr. John Riddle. "From the earliest times, women sipped herbal teas and potions made from rue, pennyroyal or Queen Anne's lace to prevent or terminate pregnancies," Riddle says. In his newest book, Eve's Herbs: A History of Contraception and Abortion in the West, he explores the history of such garden-variety methods and explores the reasons why they've largely been lost to Western women today.
"Folk medicine persists, but only in scattered pockets and out-of-the-way valleys, where women are still apt to know the secret recipes," Riddle says. Due to medical bias and religious and legal pressures, modern women no longer have access to these oral controceptives that for centuries provided their foremothers with viable, safe and effective means of regulating reproductive rates, he says.
A Lesson From Songbirds -- The high-lonesome trills of migratory songbirds are being heard less these days in unprotected parts of the southern Appalachians, as their breeding grounds fall prey to forest fragmentation, logging and development. But an ongoing study by NC State zoologist Dr. Ted Simons suggests the decline is far from irreversible.
Using hidden cameras, decoy eggs and a legion of nest spotters, Simons has studied wood thrush breeding in the Great Smoky Mountains National Park for five years. He's found that due to the protective cover of its unbroken forests, the 500,000-acre park is an irreplaceable breeding ground, producing nearly 10,000 surplus wood thrushes a year. Many of the surplus birds disperse to nonprotected lands outside the park, offsetting local population losses there, Simons says. The lesson in all this? "We need to make the park our model for regional forest management," he says. "Having few but larger preserves is more beneficial than having myriad small ones."
A ëShocking' Discovery About Plants -- A study coauthored by NC State botanist Dr. Eric Davies shows for the first time that electrical signals can stimulate rapid gene expression in plants. The study, published in the European science journal Planta, shows when an electric stimulus is used to wound a tomato leaf, bioelectrical signals are rapidly transmitted from the injured cells to other cells throughout the plant. These signals, known as action potentials, alert the cells to increase their production of naturally occurring pesticides called proteinase inhibitors, which boost the plant's resistance to insect feeding. Scientists have long known that plants possess such a defense mechanism, but until recently, most plant physiologists believed the intercellular warning signals were chemical, not electrical, in nature.
"Proving that a genuine electrical signal can turn on genes is important," says Davies, "because it raises the possibility that we may be able to use electrical stimulation as an environmentally sound means for increasing crop resistance to pests."
Concrete Images -- When NC State civil engineer Dr. Neven Krstulovic-Opara talks to people about concrete, he flashes images of the earthquake in Kobe, Japan, on the projection screen -- gloomy slides of cars crushed beneath cement rubble. "My goal is to make these images things of the past," he says. To do that, he's developed a new type of concrete called High-Performance Fiber-Reinforced Concrete (HPFRC) that's superstrong, durable and -- most importantly -- won't break apart and fall off in chunks during earthquakes. "HPFRC is designed to withstand much higher loads and deformations than traditional concrete," he says. "If failure does occur, the concrete pieces of the structure will remain stuck together, held in place by steel fibers." HPFRC also is more resistant to deterioration and cracking due to weather. Conventional concrete can develop large, connected cracks that allow water seepage and, over time, can compromise the integrity of the structure. HPRFC, in con! trast, develops disconnected cracks so fine they are barely visible, reducing the possibility of water seepage.
-- lucas --
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