10 and 100 nanometers (small enough to slip through a surgical mask)—challeng- ing researchers because of the difficulty integrating these small spatial scales. However, once Reisner’s team accounted for these “nano-droplets,” they found that the previous structural mischaracteriza- tion of clouds caused a false rendering of temperature conditions. The discovery led to a vital correction to the temperatures in the hurricane’s eye wall, the area in the storm where the most damaging winds and rainfall are located. Reisner’s two developments—proper cloud representation and lightning predic- tive models—together help demystify hurricane intensity, which may lead to more accurate predictions that help the public prepare for potential devastation. v —Kirsten Fox Agricultural Alchemy Susan Hanson wants to convert grass into gold. Stumps or stalks or weeds in a field can be burned to generate energy— emitting harmful byproducts—but Hanson and others in her field have a more elegant solution in mind: turning agricultural and for- estry waste into valuable chemicals and fuel. The sources are abundant, and this form of chemical production would not compete with demands for food, fertilizer, or water since it uses only waste products rather than requiring additional agricultural produc- tion. But the nation’s energy problems are not easily solved, and where the enormous hurdle of efficiently extracting the energy from plant matter has stumped others, this Los Alamos chemist is getting to the root of the matter: the lignin. Plant cellular walls are primarily composed of cellulose, hemicellulose, and lignin. Comprising nearly 30 percent of the biomass on Earth, lignin conducts water in stems, provides the mechanical support for the plant, and strengthens cell walls. One Los Alamos scientists are improving methods to convert agricultural waste into fuels and other valuable chemicals. gram of lignin contains about 2.27 kilojoules of energy—comparable to coal and 30 percent more than cellulose alone. But just as this woody material “glues” the cell wall together to protect plants from pests and pathogens, it protects them from research- ers as well. An efficient method is needed by which researchers can break apart the com- plex polymer’s strong bonds and degrade the plant into energy-rich simple sugars. Most research has focused on pre- treating lignin with environmentally and economically unfriendly solvents, heat, or high pressure to rupture the lignin bonds. But Hanson and Los Alamos colleagues Pete Silks and Ruilian Wu found a “green” catalyst, which enables a desired chemi- cal reaction without being consumed by it, to break down lignin into smaller chemical components. These components could potentially be used to produce alcohols, waxes, surfactants (for detergents and other applications), and fuels. Historically, precious metals such as platinum have been the basis for most catalysts, but Hanson focuses on vanadium. Found in many minerals and marine organ- isms, and often collocated with iron ores and petroleum, vanadium is an earth-abundant metal that is not toxic in the small amounts used in catalysis. The reaction proceeds in air at atmospheric pressure with only mild heat, making vanadium easier to use than most other metals, which are sensitive to air and damaged by oxidation. Hanson’s team designed and synthesized its catalysts by combining vanadium with other components. The Los Alamos work demonstrates that a lignin model compound may be broken down selectively into useful components using a vanadium catalyst. The strong carbon-carbon and carbon-oxygen bonds are cleaved via oxidation that breaks the lig- nin into smaller, usable pieces. And the only byproduct—besides the desirable, energy- rich sugars—is water. v —Kirsten Fox 1663 los alamos science and technology magazine june 2012 21