Nancy J. Hess

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The structural behavior of (11)B-, (2)H-enriched ammonia borane, ND(3)(11)BD(3), over the temperature range from 15 to 340 K was investigated using a combination of neutron powder diffraction and ab initio molecular dynamics simulations. In the low temperature orthorhombic phase, the progressive displacement of the borane group under the amine group was(More)
Dissolved organic matter (DOM) in the oceans is one of the largest pools of reduced carbon on Earth, comparable in size to the atmospheric CO2 reservoir. A vast number of compounds are present in DOM, and they play important roles in all major element cycles, contribute to the storage of atmospheric CO2 in the ocean, support marine ecosystems, and(More)
Pu L(3) X-ray near edge absorption spectra for Pu(0-VII) are reported for more than 60 chalcogenides, chlorides, hydrates, hydroxides, nitrates, carbonates, oxy-hydroxides, and other compounds both as solids and in solution, and substituted in zirconolite, perovskite, and borosilicate glass. This large database extends the known correlations between the(More)
Pu L(3) X-ray absorption fine structure spectra from 24 samples of PuO(2+x) (and two related Pu-substituted oxides), prepared by a variety of methods, demonstrate that (1) although the Pu sublattice remains the ordered part of the Pu distribution, the nearest-neighbor O atoms even at x = 0 are found in a multisite distribution with Pu-O distances consistent(More)
Soil organic matter (SOM), a complex, heterogeneous mixture of above and belowground plant litter and animal and microbial residues at various degrees of decomposition, is a key reservoir for carbon (C) and nutrient biogeochemical cycling in soil based ecosystems. A limited understanding of the molecular composition of SOM limits the ability to routinely(More)
A microfluidic pore structure etched into a silicon wafer was used as a two-dimensional model subsurface sedimentary system (i.e., micromodel) to study mineral precipitation and permeability reduction relevant to groundwater remediation and geological carbon sequestration. Solutions containing CaCl(2) and Na(2)CO(3) at four different saturation states (Ω =(More)
The cyber environment has rapidly evolved from a curiosity to an essential component of the contemporary world. As the cyber environment has expanded and become more complex, so have the nature of adversaries and styles of attacks. Today, cyber incidents are an expected part of life. As a result, cybersecurity research emerged to address adversarial attacks(More)
The number of microbial operational taxonomic units (OTUs) within a community is akin to species richness within plant/animal ("macrobial") systems. A large literature documents OTU richness patterns, drawing comparisons to macrobial theory. There is, however, an unrecognized fundamental disconnect between OTU richness and macrobial theory: OTU richness is(More)
A vast number of organic compounds are present in soil organic matter (SOM) and play an important role in the terrestrial carbon cycle, facilitate interactions between organisms, and represent a sink for atmospheric CO2. The diversity of different SOM compounds and their molecular characteristics is a function of the organic source material and(More)