abstract
MATERIALS SCIENCE
J E F F F I T LO W, I M U S H
Nanotube Forests Drink Water From Arid Air
If you don’t want to die of thirst in the desert, be like the beetle. Or have a nanotube cup handy. New research by scientists at Rice demonstrated that forests of carbon nanotubes can be made to harvest water molecules from arid desert air and store them for future use. Researchers in the lab of Rice materials scientist Pulickel Ajayan found a way to mimic the Stenocara beetle, which survives in the desert by stretching its wings to capture and drink water molecules from the early morning fog. They modified carbon nanotube forests grown through a process created at Rice, giving the nanotubes a superhydrophobic (water-repelling) bottom and a hydrophilic (water-loving) top. The forest attracts water molecules from the air and, because the sides are naturally hydrophobic, traps them inside. “It doesn’t require any external energy, and it keeps water inside the forest,” said graduate student and first author Sehmus Ozden. “You can squeeze the forest to take the water out and use the material again.” The forests grown via water-assisted chemical vapor deposition consist of nanotubes that measure only a few nanometers (billionths of a meter) across and about a centimeter long. If it becomes possible to grow nanotube forests on a large scale, the invention could become an efficient, effective water-collection device because it does not require an external energy source, the researchers said. Ajayan is Rice’s Benjamin M. and Mary Greenwood Anderson Professor in Engineering, professor of chemistry, and chair of the Department of Materials Science and NanoEngineering. The U.S. Department of Defense and the Air Force Office of Scientific Research Multidisciplinary Research Program of the University Research Initiative supported the research. Read more: ricemagazine.info/230 —Mike Williams
Rice graduate student Sehmus Ozden holds a carbon nanotube forest. Ozden treated nanotube arrays to harvest water in the same way beetles do in the desert, by combining hydrophilic and hydrophobic surfaces.
EARTH SCIENCE
Massive ‘Ultrasound’ of Mount St. Helens
Rice geophysicist Alan Levander led one of 2014’s largest scientific field experiments in July — a massive effort by more than 75 researchers to perform what amounted to a combined ultrasound and CAT scan of Mount St. Helens’ internal plumbing. The ambitious project, a joint undertaking by earth scientists at Rice, the University of Washington, the University of Texas at El Paso and other institutions, required placing more than 3,500 active seismological sensors and 23 seismic charges around the volcano over just a few days. Levander hopes to publish initial findings in 2015.
Approximate layout of shot points and seismic lines for the Mount St. Helens active seismic experiment.
The “active seismic” experiment took place July 23, 24 and 31. The tests followed two years of detailed planning and are part of a four-year project called Imaging Magma Under St. Helens (iMUSH), which could bring improvements in volcanic monitoring and advance warning systems at Mount St. Helens and other volcanoes. “Mount St. Helens and other volcanoes in the Cascade Range threaten urban centers from Vancouver to Portland, and we’d like to better understand their inner workings in order to better predict when they may erupt and how severe those eruptions are likely to be,” said Levander. Levander, Rice’s Carey Croneis Professor of Earth Science, said the instruments measured seismic waves generated by the detonation of charges in the boreholes that are each about 80 feet deep. The detonations produced vibrations that approximated a magnitude–2 earthquake, which typically cannot be felt. The National Science Foundation funded the research. Other institutions involved include Oregon State University, the Lamont-Doherty Earth Observatory, Eidgenössische Technische Hochschule Zurich and the U.S. Geological Survey. Read more about the iMUSH collaborative research project: ricemagazine.info/231 —Jade Boyd
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