For statues, stress injuries come from standing in place for hundreds of years. Using a novel technique, researchers have developed a way to predict such fracturing, applying the procedure to Michelangelo's David in an analysis that proved simpler, faster and more accurate than previous methods. Find out more in this news release.
Credit: Members of the Spatial Automation Laboratory, University of Wisconsin-Madison
Materials scientist Ali Dhinojwala first learned about the special toe structure of the gecko lizard when he attended a conference in 2002. Six years later, Dhinojwala and his colleagues were making breakthroughs in the growing field of gecko-inspired engineering. They developed an adhesive tape that sticks four times better than a gecko's foot. Read more in this Discovery.
Credit: Ali Dhinojwala, the University of Akron
Visuals can communicate research results and scientific phenomena in ways that words cannot. NSF and the journal Science sponsor the International Science & Engineering Visualization Challenge to celebrate that grand tradition--and to encourage its continued growth. The spirit of the competition is to recognize works that communicate science, engineering and technology for educational and journalistic purposes. The competition's 2010 winners were recently announced. Check out the winners in this Special Report.
Credit: Seth B. Darling, Argonne National Laboratory, Steven J. Sibener, University of Chicago
The mission of the Division of Materials Research (DMR) of the Directorate for Mathematical and Physical Sciences is to make new discoveries about the behavior of matter and materials; to create new materials and new knowledge about materials phenomena; and to address fundamental materials questions that often transcend traditional scientific and engineering disciplines and may lead to new technologies.
Exploring creative ways to fuse art and science comes naturally for Susan Eriksson, geologist and artist, who is director of education and outreach for a Boulder-based geophysics organization funded by NSF and NASA. Using materials that range from metal to wood to minerals, Eriksson creates unique pieces that are often inspired by the geological world.
April 11, 2011
Nanotechnology keeps the shine on silver
Anyone who's ever polished silver knows that keeping the tarnish at bay is never ending work. But, you may not know that polishing also rubs away some of the precious metal, whether it's your grandmother's silver bowl or a 19th century museum treasure.
"We're always looking for some kind of barrier that will protect the surface so we don't have to keep polishing it," says Terry Drayman-Weisser, director of conservation and technical research at the Walters Art Museum in Baltimore.
Twenty miles from the museum, materials scientist Ray Phaneuf and his team at the University of Maryland are working on a small solution to this big problem. With support from the National Science Foundation (NSF), they're producing and testing a protective coating so thin, you can't see it with the naked eye.
"The method that we use to apply it is called atomic layer deposition. So, literally, we're able to control the thickness of the film at a sub-nanometer level," explains Phaneuf.
Using a special reactor inside a clean room, they apply nanometer thick films of aluminum oxide to a sample silver wafer about the size of a silver dollar. Phaneuf says the films conform to the recesses and protrusions of the silver, creating a protective barrier.
Art conservators say atomic layer deposition, or ALD, will have to pass rigorous testing before they use it to protect irreplaceable treasures.
At the lab, the coating is put through a series of tests. Using a spectrometer the research team measures how light reflects off the surface of a test wafer, and how the ALD coating affects the wafer's color.
Another test measures how quickly sulfur penetrates the coated wafer. Sulfur is what tarnishes silver. The test will help determine how many layers of coating will be needed to keep the silver shiny. In another controlled chamber, the team heats a coated wafer to speed up the tarnishing. Phaneuf says this helps scientists figure out how long a barrier will last.
"Part of the challenge is to determine what the optimal thickness is that keeps sulfur off the silver surface. Eventually, thermodynamics tells us that the sulfur will diffuse through any layer we put down. The denser the layer, the slower the diffusion," explains Phaneuf. "So we'll start with films that may be a few nanometers thick and investigate the efficacy of these films all the way out to maybe a few hundred nanometers. If we can increase the lifetime of these films to a century, you may not need to do this very often."
Art conservators won't give ALD a thumbs-up until they can show that it works better than the lacquers they are using now, which have to be reapplied every decade or two. The conservators also will have to be able to remove the coating without damaging the piece.
"When it comes to art objects, the less treatment the better," says Glenn Gates, a scientist at the Walters Art Museum. "The standard treatments that use lacquers or nitrous cellulose coatings can give off a plastic look. The ALD coating is very, very thin, and orders of magnitude thinner than the wavelength of light; the idea being that it's going to impact the aesthetic presentation of the object much less than a thick organic lacquer coating that we generally apply these days."
If ALD proves a shining success, silver works of art will remain at their best for future generations to enjoy. And for many of us, it may mean never polishing silver again.
Any opinions, findings, conclusions or recommendations presented in this material are only those of the presenter grantee/researcher, author, or agency employee; and do not necessarily reflect the views of the National Science Foundation.