The Guardian: NASA’s Curiosity rover used x-ray diffraction to analyze its first Martian soil sample. Primarily composed of feldspar, pyroxene, and olivine, the sample appeared to be very similar to the basaltic soils in Earth’s volcanic regions. About half of the material was noncrystalline and appears to have been produced by the weathering of rocks. The weathering could have occurred through chemical interactions with water or oxygen, or through impacts from sandstorms or meteorites. Although x-ray diffraction has been used for examining crystals on Earth for more than 100 years, this is the first time it has been used by a spacecraft. The shoebox-sized version of traditionally refrigerator-sized equipment is also being used in the mining industry, and the Food and Drug Administration is evaluating its value for detecting counterfeit drugs.
WMD Junction: Thorium reactors are often promoted as being an alternative form of nuclear power that limits nuclear weapon proliferation risks. Unfortunately, that isn’t true. Thorium reactors begin with thorium-232, a nonfissionable material. Irradiating the thorium with neutrons (typically from a “seed” source such as uranium 235) creates protactinium-233, a highly radioactive isotope with a half-life of 27 days, which decays into uranium-233. In molten salt thorium reactors, highly pure uranium-233 is obtained by removing the protactinium-233 while it decays in order to prevent it from absorbing further neutrons (and producing protactinium-234 as a result). That makes obtaining fissionable material a relatively easy process. Although uranium-235 is the preferred source of fissionable material for weapons, enriching it is an intensely industrial process that is easily detectable. And a US test in 1955 showed that uranium-233 can be used in a nuclear weapon, albeit with a lower-than-expected yield. However, advances in industry and technology suggest that the yield could easily be adjusted upward.
BBC: Although concrete is the world’s most widely used building material, it is prone to cracking. To make the material more durable, researchers at the Delft University of Technology in the Netherlands are experimenting with adding to the concrete mix a healing agent composed of calcium lactate and alkaline-resistant bacterial spores, which remain dormant in the concrete until rainwater works its way into the cracks. As the water activates the spores, they eat the calcium lactate and produce limestone. Although the process adds considerably to the initial cost of the concrete, the researchers expect it will actually save money in the long run.
New York Times: After a federal review concluded that the $800 000 spent by one of its agencies to hold its annual regional meeting was excessive and wasteful, the Obama administration has imposed new guidelines on the amount of money that can be spent on such events. The budget cuts have provoked objections from members of several science and technology organizations, who claim that they limit the ability of the scientific community to share research and collaborate. They can also have far-reaching effects. As an example, a follow-up letter to the editor notes that such cuts can affect US troops abroad because fewer Department of Defense scientists are going to be able to attend the upcoming meeting of the American Society of Tropical Medicine and Hygiene (ASTMH). According to the letter writer, Karen Goraleski, executive director of the ASTMH, “The participation of these highly trained professionals in scientific meetings like ours is not a travel perk. They play a unique role in efforts to tackle diseases like malaria.”