[1] Data returned from the gamma-ray spectrometer onboard the Mercury Surface, Space Environment, Geochemistry, and Ranging (MESSENGER) spacecraft have been interpreted to say that Mercury is a volatile-rich planet (elevated K/Th and K/U), which is important given its heliocentric distance. The MESSENGER X-ray spectrometer provided chemical information from the surface of Mercury which we used to calculate an average surface composition for the regions analyzed. The high S abundance and low FeO abundance of the surface indicates that the oxygen fugacity of the Mercurian interior is very reducing (À6.3 to À2.6 log f O2 units below the iron-wüstite buffer). At these low oxygen fugacities, elements that are typically considered lithophile can become more siderophile or chalcophile. We review available metal/silicate partitioning data for K and U to show that Mercury's volatile inventory is still an open question, and additional experiments investigating metal/silicate partitioning at the conditions of Mercury's core formation are needed.
Metallic nickel is known to be an active, but not a selective hydrogenation catalyst for conversion of alkynes to alkenes. On the other hand, nickel oxide is not active. Recently, we have demonstrated that nickel doped into ceria provides an inexpensive catalyst for selective hydrogenation of acetylene in the presence of ethylene. Here, we evaluate various synthesis methods to achieve optimal selective hydrogenation performance. We examined incipient wetness impregnation, coprecipitation, solution combustion, and sol-gel synthesis to study how the method of preparation affects catalytic structure and behavior. Sol-gel synthesis, coprecipitation, and solution combustion synthesis methods favor nickel incorporation into the ceria lattice, while incipient wetness impregnation creates segregated nickel species on the ceria surface. For hydrogenation of acetylene, these nickel surface species lead to poor ethylene selectivity due to ethane and oligomer formation. However, when nickel is incorporated into the ceria lattice, ethane formation is prevented even while achieving 100 % conversion of acetylene. Coke formation is also significantly reduced on these catalysts compared to conventional nanoparticle counterparts. We conclude that sol-gel synthesis provides the optimal method for creating a uniform dopant distribution within the high surface area ceria.
The carbon isotope compositions (δ 13 C values) of 23 hard ciders obtainable in the United States were analyzed to detect adjuncts, specifically added C 4 sugars (i.e., corn syrup and cane sugar). In contrast, the main ingredient of hard ciders is fruit, mostly apple, juice which is derived from C 3 plants. The labeled ingredients of ciders were found to be inconsistent with the carbon isotope ratios. A higher proportion of imported ciders studied had no isotopic evidence of added C 4 -based sweetener, while most domestic ciders had elevated δ 13 C values, indicative of C 4 -based sugar additives. European ciders could contain beet sugar, a common sweetener used in that region, which would not be detected as an additive because it is a C 3based sweetener. The δ 13 C values of the ciders were found to have no correlation with the amount of sugar in the cider, as reported on the nutritional information label, likely reflecting varying fermentation times. An increase in the amount of added C 4 sugars did not correspond to a decrease in price, in contrast to what is found in beers.
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