Pacific Northwest National Laboratory

About: Pacific Northwest National Laboratory is a facility organization based out in Richland, Washington, United States. It is known for research contribution in the topics: Catalysis & Aerosol. The organization has 11581 authors who have published 27934 publications receiving 1120489 citations. The organization is also known as: PNL & PNNL.

Microbiological and Geochemical Heterogeneity in an in Situ Uranium Bioremediation Field Site

Abstract: The geochemistry and microbiology of a uranium-contaminated subsurface environment that had undergone two seasons of acetate addition to stimulate microbial U(VI) reduction was examined. There were distinct horizontal and vertical geochemical gradients that could be attributed in large part to the manner in which acetate was distributed in the aquifer, with more reduction of Fe(III) and sulfate occurring at greater depths and closer to the point of acetate injection. Clone libraries of 16S rRNA genes derived from sediments and groundwater indicated an enrichment of sulfate-reducing bacteria in the order Desulfobacterales in sediment and groundwater samples. These samples were collected nearest the injection gallery where microbially reducible Fe(III) oxides were highly depleted, groundwater sulfate concentrations were low, and increases in acid volatile sulfide were observed in the sediment. Further down-gradient, metal-reducing conditions were present as indicated by intermediate Fe(II)/Fe(total) ratios, lower acid volatile sulfide values, and increased abundance of 16S rRNA gene sequences belonging to the dissimilatory Fe(III)- and U(VI)-reducing family Geobacteraceae. Maximal Fe(III) and U(VI) reduction correlated with maximal recovery of Geobacteraceae 16S rRNA gene sequences in both groundwater and sediment; however, the sites at which these maxima occurred were spatially separated within the aquifer. The substantial microbial and geochemical heterogeneity at this site demonstrates that attempts should be made to deliver acetate in a more uniform manner and that closely spaced sampling intervals, horizontally and vertically, in both sediment and groundwater are necessary in order to obtain a more in-depth understanding of microbial processes and the relative contribution of attached and planktonic populations to in situ uranium bioremediation.

Motivating Residents to Conserve Energy without Financial Incentives

Abstract: Given the aim to motivate people to conserve energy in homes, we need to understand what drives people’s energy use behavior and how it can be influenced. This article describes applied energy conservation campaigns at two U.S. military installations where residents do not pay their own utility bills. Customized approaches were designed for each installation based on a broad social-psychological model. Before-and-after energy use was measured, and residents were surveyed about end use behaviors. Residents said they were motivated by the desire to do the right thing, set good examples for their children, and have comfortable homes. For sustained change, respondents recommended continued awareness and education, disincentives, and incentives. Findings support some aspects of a social-psychological model, with emphasis on altruistic and egoistic motives for behavioral change. These studies may have implications for situations where residents are not billed for individual energy use, including other governmen...

A Photoelectron Spectroscopic and Theoretical Study of B16− and B162−: An All-Boron Naphthalene

Abstract: The structure and chemical bonding of B16− were studied using ab initio calculations and photoelectron spectroscopy. Its global minimum is found to be a quasi-planar and elongated structure (C2h). Addition of an electron to B16− resulted in a perfectly planar and closed shell B162− (D2h), which is shown to possess 10 π electrons with a π-bonding pattern similar to that of naphthalene and can thus be considered as an “all-boron naphthalene”, a new member in the growing family of hydrocarbon analogues of boron clusters.

Determining the Overpotential for a Molecular Electrocatalyst

Abstract: “The additional potential (beyond the thermodynamic requirement) needed to drive a reaction at a certain rate is called the overpotential.”1 Over the last decade there has been considerable interest in the design and testing of molecular electrocatalysis for the interconversion of renewable energy and chemical fuels.2-5 One of the primary motivations for such research is the replacement of expensive and rare precious metal catalysts, such as platinum, with cheaper, more abundant metals.2,6-8 To become competitive with current electrocatalytic energy conversion technologies, new catalysts must be robust, fast, and energy-efficient. This last feature, the energy-efficiency, is dependent upon the overpotential. For molecular catalysts, the determination and reporting of overpotentials can be complicated by the frequent dependence on assumptions, especially when working in nonaqueous solvents. As overpotentials become lower, the meaningful comparison of molecular catalysts will require improved accuracy and precision. The intended purpose of this viewpoint is to provide a clear and concise description of overpotential and recommendation for its determination in molecular electrocatalysis. This material is based upon work supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences.

Self‐Assembled Fe–N‐Doped Carbon Nanotube Aerogels with Single‐Atom Catalyst Feature as High‐Efficiency Oxygen Reduction Electrocatalysts

Abstract: Self-assembled M-N-doped carbon nanotube aerogels with single-atom catalyst feature are for the first time reported through one-step hydrothermal route and subsequent facile annealing treatment. By taking advantage of the porous nanostructures, 1D nanotubes as well as single-atom catalyst feature, the resultant Fe-N-doped carbon nanotube aerogels exhibit excellent oxygen reduction reaction electrocatalytic performance even better than commercial Pt/C in alkaline solution.