Most of the stories coming from the Gulf Coast in the aftermath of the 2005 hurricane season have centered around human and economic tragedy, which is as it should be. People lost their lives, their homes, and their livelihoods. An entire city may have lost its identity. But there are also stories that lie beneath the surface, like the mold that’s proliferating in New Orleans.

An October 2005 report issued by the Mold Work Group of the Center for Disease Control and Prevention stated, “The duration and extent of flooding and the number of structures flooded as a result of Hurricanes Katrina and Rita make the likelihood of massive mold contamination in buildings a certainty.” This wasn’t news to Jennifer R. Woertz, assistant professor of civil engineering and geological sciences. She had already submitted a proposal and been awarded a grant from the Small Grants for Exploratory Research program of the National Science Foundation in September 2005.

At that time Woertz, in collaboration with Wilasa Vichit-Vadakan, the Clare Boothe Luce Assistant Professor of Civil Engineering and Geological Sciences, and Dustin Poppendieck, assistant professor of environmental resources engineering at Humboldt State University in Arcata, Calif., were finalizing plans to study eight homes in the Orleans Parish over a three-month period in order to determine the type and extent of mold growing in the homes, as well as establish a guide for safe reconstruction efforts in the area.

In addition to monitoring the moisture content of the materials in the homes, the team monitored the levels of mold in the ambient air. “Mold is hydrophobic,” says Woertz. “It’s very difficult for spores, which are two to five microns in diameter, to infest a material when the material is saturated. So we didn’t expect to record a lot of mold until the drying out process began.”

The spores the team found, mostly penicillium and aspergillus, are two types of molds that can cause respiratory problems, triggering allergies or exacerbating asthma. They can also cause skin infections in people with weaker immune systems. “We’re expecting to see a variety of health problems arise in the months to come — affecting the evacuees returning to live as well as workers attempting reconstruction,” says Woertz. “Proper respirators will be vital for construction workers. But it is especially important that people whose immune systems are compromised, such as the elderly or small children, not return to contaminated homes.”

Woertz’s concern is that unlike asbestos and lead, which are controlled by strict Environmental Protection Agency guidelines, no clear cut ties exist between increased respiratory problems, such as asthma, and mold contamination. For this reason, there are no standards or threshold limits as to the amount of mold that is acceptable in a home. There are also no governmental certifications given to companies who claim they remove mold.

Another concern that the study addressed is the structural integrity of the buildings. Although it does not grow quickly, mold eats whatever it is growing on to survive. It is also very difficult to remove. Because it is everywhere, it is impossible to completely remove. Contractors in New Orleans will need to work under negative pressure, venting the air, and the airborne spores released by the demolition process, outside. The next step should involve a HEPA vacuum or filtration process, to make sure as many of the spores have been removed as possible. According to Vichit-Vadakan, should the mold attached to surfaces not be removed, it could cause dry rot and destroy the structural integrity of a building.

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New Class of Materials Discovered

“No one has seen anything like these materials,” says Peter C. Burns, the Henry J. Massman Jr. Chair of the Department of Civil Engineering and Geological Sciences. He’s speaking of the actinyl peroxide compounds that he and Lynda Soderholm, a chemist at Argonne National Laboratory, discovered. These nano-sized compounds, which represent a new class of materials, are believed to be important in environmental systems because of the way they could impact the transport of heavy metals and radionuclides in geologic fluids.

Burns and Soderholm believe that these nanospheres most likely form in alkaline mixtures of nuclear waste, such as in nuclear waste tanks. They encountered the materials during studies conducted in conjunction with the Environmental Molecular Science Institute at Notre Dame. As the research continued, the project was moved to Argonne because its facilities enabled safe interaction with neptunium. Argonne’s Advanced Photon Source was also used during the studies.

Formed from uranium and neptunium peroxide solutions, actinyl peroxide compounds self-assemble into nano-sized shells that may prove useful in a variety of applications. For example, if these nanostructures could be harnessed and manufactured, industry could use them as catalysts, computer chips, solar cells, flexible batteries, or data storage devices.

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Feasibility of Permanent Moon Base Questioned

Clive R. Neal, associate professor of civil engineering and geological sciences, is one of a 15-member team of planetary geologists examining moonquakes and the effect they may have on a future permanent moon base. Using data from seismometers placed at lunar landing sites between 1969 and 1972 and collected through 1977, the team discovered four different types of moonquakes, which could impact any structure constructed on the surface of the moon.

The types of quakes identified from the more than 12,000 events recorded, include quakes generated by meteorite strikes; deep moonquakes, which occur approximately 700 kilometers below the surface; thermal moonquakes, which occur close to the surface as a result of temperature fluctuations at dawn when the sun hits the surface of the moon; and shallow moonquakes, which occur only 20 to 30 kilometers below the surface.

Although classified as “shallow,” these types of quakes are the most powerful and long-lasting. According to Neal, a few of the shallow quakes measured up to 5.5 on the Richter scale. “Most earthquakes last a minute or two,” says Neal. “Shallow moonquakes can last up to 10 minutes.” Because the seismometers were placed in a relatively small region of the moon, the data is inconclusive, but it does suggest that additional analysis is needed before constructing a permanent lunar base.

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Project Confirms Skyscraper Design

The initial results of the Chicago Full-scale Monitoring Project as reported in the November 2005 issue of Engineering News Record show that U.S. design assumptions are generally valid in predicting building sway. The three skyscrapers featured in the study have been performing as previously predicted, although they have not yet faced a severe storm.

Ahsan Kareem, the Robert Moran Professor of Civil Engineering and Geological Sciences and director of the Natural Hazards Laboratory (NatHaz), led the study in collaboration with Tracy Kijewski-Correa, the Rooney Family Assistant Professor of Civil Engineering and Geological Sciences. They worked in conjunction with Skidmore, Owings & Merrill (SOM), a leading architecture firm, and Canada’s Boundary Layer Wind Tunnel Laboratory. The team was funded by the National Science Foundation and is currently seeking more funding to expand the study.

The project involved fitting three Chicago buildings with accelerometers, which were able to detect each skyscraper’s motion along perpendicular axes, as well as any twisting movement. Data from the instruments were transmitted to a communication hub in Chicago’s SOM building and then relayed to Notre Dame. Results indicated that the buildings have been responding in accordance with their design, even though they were built when scale-model testing and computer modeling techniques were not as advanced as they are today.

NatHaz, which coordinated the study at the University of Notre Dame, was created in 2000 to quantify the load effects caused by natural hazards on structures, such as winds, waves, and earthquakes. Researchers in the lab also seek to develop innovative strategies to mitigate and manage the effects of these hazards.

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