ORNL Wins Five R&D 100 Awards
ORNL's award-winning magnetic spectral receiver was developed by (from left) Steve Kercel, Robert Rochelle, and Mike Moore. It provides low-cost, highly accurate magnetic field monitoring in facilities where sensitive instruments are used. Photograph by Bill Norris.
ORNL researchers received five R&D 100 Awards in 1995, bringing the Laboratory's total of these awards to 79. The awards are presented annually by R&D magazine in recognition of the year's most significant technological innovations.
Four awards were for research performed exclusively at ORNL, and the fifth was for a joint entry with 3M Company of St. Paul, Minnesota.
The awards were for the following processes or inventions:
To address this problem, ORNL researchers have developed an instrument to detect electromagnetic interference (EMI) caused by magnetic fields. EMI can cause disruptions in some of the high-performance digital control systems in nuclear power plant control rooms and in industries using similar sophisticated instrumentation.
The ORNL device, called the magnetic spectral receiver, provides low-cost, highly accurate monitoring of magnetic fields in diverse facilities where instrumentation is vital to their operation. By knowing the exact levels of EMI present, design engineers can more accurately specify the amount of EMI resistance required to protect sensitive instruments. To be safe, engineers typically call for greater EMI resistance, or "hardness," than is actually needed. Using more shielding than necessary, for example, is extremely costly and wasteful.
"EMI resistance is achieved primarily by adding shielding," says Steve Kercel, principal inventor of the magnetic spectral receiver, which received an R&D 100 Award this year from R&D magazine. "However, other elements affecting EMI hardness are physical layout, proper termination of cables, and the judicious selection of software algorithms.
"The big issue is that all measures intended to improve EMI resistance are expensive, and it is desirable to use the least that you can get away with and still have the system work properly. Experts estimate that proper knowledge of ambient EMI would allow designers to save half the cost of digital instrumentation and controls packaging."
The magnetic spectral receiver, which at 65 pounds is portable, is one of the world's first devices that uses the wavelet transform, a processing system that provides analysis of transient, or very brief, effects that conventional receivers miss. Instead, these receivers treat the transient peaks as an EMI average, which fails to tell the whole story.
"It's similar to driving 100 miles per hour for an hour and then driving 30 miles per hour for an hour," Kercel says. "Your average speed is 65, but that number doesn't really paint an accurate picture."
Another advantage of the magnetic spectral receiver is its low cost. Although conventional EMI receivers cost up to $75,000, the ORNL unit would cost about $8000 when produced in reasonable quantities. One reason that other receivers cost more is that they provide high precision, resolution, and dynamic range. However, these capabilities are not needed for ambient surveys. In addition, the magnetic spectral receiver requires no attendant, considerably reducing labor costs over the typical 3-week monitoring period.
Although the magnetic spectral receiver is primarily intended for nuclear power plant control rooms, Kercel also expects it to be used by the textile and semiconductor fabrication industries. "Both industries suffer seemingly inexplicable failures of digital control equipment and suspect ambient EMI as the culprit," Kercel says. Companies in both industries have expressed interest in the receiver.
The same basic technology used in the magnetic spectral receiver could be modified for use in real-time environmental monitoring, surveillance, detection, and signature identification. In these applications the wavelet processor could be adapted to identify crucial features from the transient components of the signal. For example, Kercel says, by substituting a seismic transducer for the magnetic antenna and replacing a couple of other internal parts, the receiver could be converted into a seismic monitor. The receiver can also be configured as a gunshot detector that would not be susceptible to other noises, such as thunder or vehicle backfires.
Other ORNL researchers who developed the award-winning receiver are William Dress, Robert Rochelle, and Michael Moore.
Calibrator Measures Flow Rate of Corrosive Gases
Normally, measuring flow rates of corrosive and toxic gases takes several days. But anyone using the new calibrator developed by ORNL researchers can complete the task in only a few minutes. Flow rate is measured by weighing corrosive gases accumulating at volume rates as low as a few cubic centimeters per minute.
ORNL's award-winning gravimetric gas flow calibrator, which was developed by Carl Remenyik (shown here), provides for accurate calibration of gas flow meters with corrosive or noncorrosive gases. The calibrator was originally developed for use in the semiconductor industry, but Remenyik expects it to have several other applications. Photograph by Bill Norris.
The gravimetric gas flow calibrator is a new type of gas flow calibration device that measures how fast any type and quantity of gas flows through gas flow meters, according to Carl Remenyik, the ORNL researcher who developed the device. By measuring the flow of gas in a minute, scientists can ensure that the gases, no matter how small an amount, are being discharged in precise doses during semiconductor manufacturing processes.
"The calibrator is significantly more accurate than other volumetric devices, many of which can operate only with nonreactive gases," says Remenyik, an engineer in the Instrumentation and Controls Division. "Strongly reactive gases eat away at most metals, but the calibrator is made of a stainless steel that will resist attacks. It will operate with almost any type of gas or vapor, and its accuracy is not affected by chemical reactions, condensation, or adsorption taking place inside."
Accurately weighing small quantities of flowing gas is difficult, says Remenyik. Most methods determine the weight of gas by measuring it on a balance that requires a long time to collect samples or by deriving it from equations relating temperature, volume, and pressure. Measuring temperature, volume, and pressure are indirect mass measurement methods that will have some errors that accumulate in the calculations.
"Because this calibrator does not depend on calculation of the gas density from pressure and temperature measurements," Remenyik says, "it is fundamentally more accurate than volumetric devices."
Also, balances that can measure 50- to 100-pound objects, the weight range of most gas containers, cannot accurately measure a few tenths of an ounce of gas inside the container. Scientists usually must spend hours or days collecting gas heavy enough to be weighed. Chemical reactions and adsorption significantly reduce the accuracy of indirect methods that derive the gas weight.
In the semiconductor industry, high-quality wafer chips require accuracy in the control of gas flow. Dozens of gases in small doses are used to manufacture semiconductor chips. The chips, which may be as small as the tip of a finger, are used in electronic devices, such as televisions, radios, and computers.
The ORNL calibrator, which won an R&D 100Award from R&D magazine this year, uses a patented technique to measure the weight of gas. From a load cell balance, scientists suspend an empty vessel submerged in water to balance its weight by buoyancy. While submerged, the 50-pound steel container feels no heavier than one-tenth of an ounce. The container seems lighter because water pushes against objects, causing them to float like a log in a river. With a lighter calibration container, scientists can use a load cell sensitive enough to measure fractions of one-thousandth of an ounce. The flow rate is then determined by subtracting the weight of the empty, submerged calibration container from the weight of a calibrator filled with gas for 1 minute.
"The key to accuracy is the type of balance used to measure weight," Remenyik says. "Balances are made for a particular range of weight. A balance for weighing hundreds of pounds will not accurately weigh a few ten-thousandths of an ounce of a gas. This is why our technique is important. Because water takes away the bulk of weight, we can use the best balance available for accurate small measurements."
The calibration process begins and ends with the push of a button. In the first push, a valve seals off the normal path and reroutes the gas to an empty calibrator for a specific time interval, usually 1 minute. With the second push, the valve closes again and the gas continues to flow through the regular path. The test sample is then measured by the load cell. In the final push, the test sample is moved to an incinerator, where it is burned to harmless waste.
In addition to the semiconductor industry, gas flow calibrators can be used in standard laboratories and in other branches of the industry where gas flow controllers and meters are used. Funding for the gas flow calibrator was provided by ORNL's Metrology Program and the semiconductor industry.
Restructuring a Mountain: Nature vs Human Intervention
Some of the land devastated by the May 18, 1980, volcanic eruption of Mount St. Helens is turning into a vast tree plantation. In other areas, native grasses and legumes are beginning to flourish. Fifteen years after the mountain blew, killing 85 persons and destroying property and natural ecosystems, it is taking on a life of its own.
Birds perch on dead, fully stripped tree trunks standing tall like telephone poles. Around the trees lie their fallen neighbors, strewn on the ground like pickup sticks by Nature's "blast from the past" method of instant logging. But nearby are newly planted Douglas fir trees and Pacific silver fir trees. Thanks to these fast-growing native trees and the return of grasses, wildflowers, and other natural species in other areas, tourists are now witnessing the "greening" of the once barren land around the mountain.
This rebirth amid death and destruction that marks the 15-year recovery of the Mount St. Helens ecosystem is of interest to scientists as well as tourists. Virginia Dale, a mathematical ecologist and associate director of ORNL's Environmental Sciences Division, has been studying plant recovery in the Mount St. Helens area since the eruption. She presented a paper on her findings on July 31, 1995, at the annual meeting of The Ecological Society of America in Snowbird, Utah.
Dale studied the devastation soon after the eruption and has since conducted a series of periodic surveys and analyses of the recovery. This year she completed work on her sixth survey of the region.
"Although it will take at least a century for the area to fully return to preeruption conditions," she says, "the data from the first 15 years show a strong and steady recovery.
The 1980 eruption, Dale says, created seven types of disturbances. They were the development of the crater, the flow of hot gases, the largest avalanche in history, a zone in which most trees were blown over, an area where needles were burned off the trees but the trees remained standing, ash deposits, and mud flows.
"My work is on the debris avalanche, which was one of the most heavily devastated areas," Dale says. "The recovery in each of the areas is unique."
View of a forest near Mount St.Helens 15 years after destruction by the volcano's eruption.
A native grass flourishes on the debris avalanche created by the 1980 eruption of Mount St. Helens (in the background).
The Mount St. Helens National Monument was created in 1983 to protect 110,000 acres of the devastated area, which includes a pumice plain (pumice is lightweight volcanic glass full of cavities). This area is now left to recover in a natural manner.
"The rest of the devastated area--about 136,000 acres--is owned by the U.S. Forest Service, the state of Washington, or private owners," Dale says. "It is being actively managed largely for forestry. Plantations of two native species, Douglas fir and Pacific silver fir, will be harvested in about 60 years."
Dale notes that the area she studies is recovering from the eruption but still has a long way to go. In September 1980, the total number of plant species found in an area that suffered some of the worst devastation, the avalanche zone, was only 20. Her 1994 survey found 156 species of plants in the same area, much closer to the original 256 species found in the area before the eruption.
Her studies suggest that human efforts to help the recovery have probably done more harm than good. An immediate concern after the eruption was the possibility of massive erosion. To prevent it, the U.S. Soil Conservation Service, now known as the Natural Resources Conservation Service, planted nonnative, or exotic, grass and legume seeds (including bird's foot trefoil) in selected areas despite scientists' objections.
The concerns of these scientists were justified according to Dale's research. In the areas where these exotic seeds were spread, the nonnative plants thrived, slowing the return of the native species. However, Dale's recent surveys show that the tide has turned: the native species are surviving and growing even in the presence of the exotic ones.
For example, between 1983 and 1989, several species of trees, including the Douglas fir, declined in density in areas that had a large concentration of nonnative plants. But, between 1989 and 1994, the native trees in these areas are surviving and growing along with the exotic species.
"A dramatic effect of the exotic plants can be seen," Dale says, "but over time the native plants have done quite well at regaining their territory." Partly because of this experience, the Natural Resources Conservation Service now stocks its field stations with a variety of seeds native to each area.
Although the area still has a long way to go to achieve full plant recovery, Dale is encouraged by the progress she sees.
"In the absence of humans doing anything," she notes, "succession is occurring. And where humans did intervene, succession is also occurring, but just a bit more slowly."
Food Dye May Raise Risk of Breast Cancer
Eating foods containing a commonly used synthetic dye may raise a woman's risk of developing breast cancer, according to research conducted at ORNL and recently reported in the journal Cancer Letters. Synthetic food dyes are added to many foods and beverages to improve their appearance.
"Food dyes, pesticides such as DDT, and pollutants may be responsible for the increasing breast cancer rate among American women because they mimic the effects of the hormone estrogen," says Craig Dees, head of the Molecular Toxicology Group in ORNL's Health Sciences Research Division. "Some researchers have suggested that these so-called environmental estrogens may be helping to cause the worldwide decrease in human sperm counts and are the cause of reproductive abnormalities in animals. They also have natural estrogen's ability to attach to breast cells and order them to rapidly reproduce, a process that is required to cause cancer."
Using a new highly sensitive and specific test, ORNL researchers have found that Red Dye No. 3 is a "complete carcinogen" because it carries out the two actions that together cause cancer. First, it damages the DNA, or genetic material, in breast cells. Second, it gives cells the order to grow out of controlthat is, divide more rapidly than normal. This second finding suggests that the synthetic food dye is an environmental estrogen. The research was supported by the Laboratory Directed Research and Development fund supported by DOE.
Dees says there is evidence that other food dyes may also damage DNA. But ORNL studies show that Red Dye No. 3 is more likely to cause breast cancer because it also issues an order for these cells to grow.
Americans' exposure to pesticides has dropped in recent years, according to a study by Curtis Travis, director of ORNL's Center for Risk Management. However, Dees says that today Americans eat food that may contain levels of synthetic food dyes that are at least 10 million times higher than the level of pesticides. Since 1979, he adds, the production of synthetic dyes for the food industry has increased 5% per year.
"The health risk of dyes may be rising because our diet is increasingly made up of processed foods that are more likely to contain food dyes," Dees says. "These foods include lunch meats, hots dogs, snack foods, and candies. Beverages also contain food dyes. Synthetic food colorants, like Red Dye No. 3, are less expensive than natural dyes, so use of these colorants is increasing."
One of eight women in the United States develops breast cancer, which annually kills almost 50,000 American women. Dees says a woman's risk of getting breast cancer may be linked to increased body fat, poor exercise habits, and a diet high in fat, and in perhaps 5% of the cases, to an inherited genetic defect. But he believes that environmental estrogens in food may play the most important role in the development of breast cancer.
"American women are approximately 5 times more likely to develop breast cancer than are women in less developed countries," Dees says. "Diet and lifestyle may explain this difference. When women from less developed countries adopt a westernized diet and lifestyle, their cancer risks equal those of women in the United States."
Red Dye No. 3, which is ingested by American women in large amounts, is capable of binding to the estrogen receptor and mimicking the natural hormone along with other environmental estrogens such as the pesticide DDT.
Dees and associate Don Henley determined that Red Dye No. 3 is a complete carcinogen by using a highly sensitive and specific technique called a gel mobility shifter assay. In one test, Henley extracted a naturally produced tumor suppressor protein (called p53) from breast cells exposed to Red Dye No. 3 as well as from breast cells exposed to other dyes and to DDT. Before it was extracted, the p53 protein had "sensed" that DNA in the cells exposed to Red Dye No. 3 had been damaged. Its response was to grab the DNA in a certain region to tell the cell to stop growing so that repairs could be made before the cell reproduced.
The extracted protein instead grabbed a radioactively labeled double strand of synthetic genetic material as part of the gel mobility shift test. This strand is identical to the genetic region to which the p53 protein normally binds within a cell. The strength or amount of the grabbing by the p53 protein caused the radioactive DNA to move very slowly and collect in one place in a gel subjected to an electric field (gel electrophoresis). This effect was revealed as a thick dark band on X-ray film laid over the gel, because the film is sensitive to radioactivity.
"The increased binding of p53 proteins to the synthetic genetic material was at least as high for cells exposed to Red Dye No. 3 as for cells treated with other DNA-damaging chemicals or exposed to radiation," Dees says. "We believe that the p53 proteins are trying to stop the breast cells from duplicating themselves after they are exposed to the red dye so that abnormal genetic material is not copied. If the p53 proteins are prevented from doing their job, then cells eventually grow out of control, leading to cancer."
Using another gel shifter technique, Dees' associate Scott Garrett studied a synthetic DNA fragment that binds an estrogen receptor from a human breast cell. An estrogen receptor is a protein that is assembled in a breast cell after binding to an estrogen. Once a receptor is assembled in response to exposure to an estrogen or estrogenlike substance, it then attaches to specific sites in the DNA that tell the cell's nucleus to reproduce. Exposure to estrogen or Red Dye No. 3 could tell breast cells containing damaged DNA to proliferate.
For the gel mobility test, Garrett introduced a synthetic version of this DNA along with estrogen receptors produced in breast cells by exposure to Red Dye No. 3. The test showed that the newly formed estrogen receptors extracted from breast cells bind strongly to the synthetic DNA fragment in the gel. Thus, in addition to damaging DNA, Red Dye No. 3 is acting like an environmental estrogen by binding to estrogen receptors just like DDT.
"By binding the estrogen receptor, the dye is telling the cells to reproduce rapidly," Dees said. "This result suggests that exposure to Red Dye No. 3 could significantly increase the risk that breast cells become cancerous."
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