Bioresource and Agricultural Engineering Commons^™

Pore Scale Analysis Of The Impact Of Mixing-Induced Reaction Dependent Viscosity Variations, S.M. Davison, H. Yoon, M. J. Martinez

United States Department of Energy: Publications

Expanding interest in enhanced subsurface natural resource recovery and carbon sequestration motivates study of reacting flows in porous media. In this work, we examine the case of reaction products that increase or decrease the viscosity of the fluid. Parallel reactant streams flow through porous media and react transversely along the centerline. We utilize a pore scale, finite element numerical method that couples the reaction with fluid flow through two arrangements of porous media at three Damkohler (Da) numbers and two viscosity conditions. When the product increases the fluid viscosity, the flow velocity is reduced and higher amounts of …

The Fundamental Equation Of Eddy Covariance And Its Application In Flux Measurements, Lianhong Gu, William J. Massman, Ray Leuning, Stephen Pallardy, Tilden Meyers, Paul Hanson, Jeffery Riggs, Kevin Hosman, Bai Yang

United States Department of Energy: Publications

A fundamental equation of eddy covariance (FQEC) is derived that allows the net ecosystem exchange (NEE) N̅s of a specified atmospheric constituent s to be measured with the constraint of conservation of any other atmospheric constituent (e.g. N2, argon, or dry air). It is shown that if the condition │N̅s│ ˃˃ │X̅s│ │N̅co2│is true, the conservation of mass can be applied with the assumption of no net ecosystem source or sink of dry air and the FQEC is reduced to the following equation and its approximation for horizontally homogeneous mass fluxes:

N̅_s = c̅_dw’X’_{s …}

A Non-Premixed Combustion Model Based On Flame Structure Analysis At Supercritical Pressures, Guilhem Lacaze, Joseph Oefelein

United States Department of Energy: Publications

This work presents a study of non-premixed flames at supercritical-pressure conditions. Emphasis is placed on flame stability in liquid rocket engines fueled with liquid oxygen and gaseous hydrogen. The flame structure sensitivity to strain, pressure, temperature and real-fluid effects was investigated in detailed opposed-jet flames calculations. It is shown that the flame is very robust to strain, that the flamelet assumption is valid for the conditions of interest, and that real-fluid phenomena can have a significant impact on flame topology. At high-pressure supercritical conditions, small pressure or temperature variations can induce strong changes of thermodynamic properties across the flame. A …

Field Ion Source Development For Neutron Generators, B. Bargsten Johnson, P. R. Schwoebel, C. E. Holland, P. J. Resnick, K L. Hertz, D L. Chichester

United States Department of Energy: Publications

An ion source based on the principles of electrostatic field desorption is being developed to improve the performance of existing compact neutron generators. The ion source is an array of gated metal tips derived from field electron emitter array micro fabrication technology. A comprehensive summary of development and experimental activities is presented. Many structural modifications to the arrays have been incorporated to achieve higher tip operating fields, while lowering fields at the gate electrode to prevent gate field electron emission which initiates electrical breakdown in the array. The latest focus of fabrication activities has been on rounding the gate electrode …

Numerical Simulation Of Expansion And Charring Of Carbon-Epoxy Laminates In Fire Environments, Matthew Mcgurn, Paul Desjardin, Amanda Dodd

United States Department of Energy: Publications

A thermal model is developed for the response of carbon-epoxy composite laminates in fire environments. The model is based on a porous media description that includes the effects of gas transport within the laminate along with swelling. Model comparisons are conducted against the data from Quintiere et al. [34]. Verifications are conducted for both coupon level and intermediate scale one-sided heating tests. Comparisons of the heat release rate (HRR) and time-to-ignition as well as the final products (mass fractions, volume percentages, porosity, etc.) are conducted. Overall, the agreement between available the data and model is good considering the simplified approximations …

Combined Finite Element And Peridynamic Analyses For Predicting Failure In A Stiffened Composite Curved Panel With A Central Slot, Erkan Oterkus, Erdogan Madenci, Olaf Weckner, Stewart Silling, Philip Bogert, Alexander Tessler

United States Department of Energy: Publications

This study presents an analysis approach based on a merger of the finite element method and the peridynamic theory. Its validity is established through qualitative and quantitative comparisons against the test results for a stiffened composite curved panel with a central slot under combined internal pressure and axial tension. The predicted initial and final failure loads, as well as the final failure modes, are in close agreement with the experimental observations. This approach demonstrates the capability of the PD approach to assess the durability of complex composite structures.

A Reaction Progress Variable Modeling Approach For Non-Ideal Multiphase Explosives, K. P. Ruggirello, P. E. Desjardin, M. R. Baer, M. J. Kaneshige, E. S. Hertel

United States Department of Energy: Publications

This study concerns the development of a mixture fraction based reaction progress variable formulation for aluminized explosives. Highlights of the formulation include a fully compressible treatment of both the gas and solid phases (both aluminum and alumina), heterogenous and homogenous reactions, and effects of group combustion. Isolated particle simulations are validated against experimental data and DNS and show good agreement of burn times over a range of pressure and oxygen environments. The new models are implemented in the CTH shock physics code using a fractional step approach to allow for efficient computation of particle dynamics. Comparisons are made to experimental …

An Experimental And Theoretical Study Of Heat And Mass Transfer During The Venting Of Gas From Pressure Vessels, W. S. Winters, G. H. Evans, S. F. Rice, R. Greif

United States Department of Energy: Publications

Non condensing gas flow and heat transfer during venting of vessels are studied using experiments and analysis. A high pressure helium supply vessel is connected to a low pressure receiver via orifice and tubing. A single control volume analysis and a multi-dimensional analysis are used to predict pressure and mass-averaged temperature in the supply. Experiments utilizing transient PVT methods are conducted to obtain transient pressure and mass-averaged temperature data for validating the analysis. Measured transient pressures and mass-averaged temperatures in the supply are reproduced by analysis. Heat transfer is due to natural convection except for the early part of transfer.

A Functional Description Of Cyma, An Electron-Transfer Hub Supporting Anaerobic Respiratory Flexibility In Shewanella, Sophie J. Marritt, Thomas G. Lowe, Jordan Bye, Duncan G. G. Mcmillan, Liang Shi, James K. Fredrickson, John M. Zachara, David J. Richardson, Myles R. Cheesman, Lars J. C. Jeuken, Julea N. Butt

United States Department of Energy: Publications

CymA (tetrahaem cytochrome c) is a member of the NapC/NirT family of quinol dehydrogenases. Essential for the anaerobic respiratory flexibility of shewanellae, CymA transfers electrons from menaquinol to various dedicated systems for the reduction of terminal electron acceptors including fumarate and insoluble minerals of Fe(III). Spectroscopic characterization of CymA from Shewanella oneidensis strain MR-1 identifies three lowspin His/His co-ordinated c-haems and a single high-spin chaem with His/H₂O co-ordination lying adjacent to the quinolbinding site. At pH 7, binding of the menaquinol analogue, 2-heptyl-4-hydroxyquinoline-N-oxide, does not alter the midpoint potentials of the high-spin (approximately −240 mV) …

Exploring The Biochemistry At The Extracellular Redox Frontier Of Bacterial Mineral Fe(Iii) Respiration, David J. Richardson, Marcus J. Edwards, Gaye F. White, Nanakow Baiden, Robert S. Hartshorne, James K. Fredrickson, Liang Shi, John M. Zachara, Andrew J. Gates, University Of East Anglia, Thomas Clarke

United States Department of Energy: Publications

Many species of the bacterial Shewanella genus are notable for their ability to respire in anoxic environments utilizing insoluble minerals of Fe(III) and Mn(IV) as extracellular electron acceptors. In Shewanella oneidensis, the process is dependent on the decahaem electron-transport proteins that lie at the extracellular face of the outer membrane where they can contact the insoluble mineral substrates. These extracellular proteins are charged with electrons provided by an inter-membrane electron-transfer pathway that links the extracellular face of the outer membrane with the inner cytoplasmic membrane and thereby intracellular electron sources. In the present paper, we consider the common structural …

Img: The Integrated Microbial Genomes Database And Comparative Analysis System, Victor M. Markowitz, I-Min A. Chen, Krishna Palaniappan, Ken Chu, Ernest Szeto, Yuri Grechkin, Anna Ratner, Biju Jacob, Jinghua Huang, Peter Williams, Marcel Huntemann, Iain Anderson, Konstantinos Mavromatis, Natalia N. Ivanova, Nikos C. Kyrpides

United States Department of Energy: Publications

The Integrated Microbial Genomes (IMG) system serves as a community resource for comparative analysis of publicly available genomes in a comprehensive integrated context. IMG integrates publicly available draft and complete genomes from all three domains of life with a large number of plasmids and viruses. IMG provides tools and viewers for analyzing and reviewing the annotations of genes and genomes in a comparative context. IMG’s data content and analytical capabilities have been continuously extended through regular updates since its first release in March 2005. IMG is available at http://img.jgi.doe.gov. Companion IMG systems provide support for expert review of genome annotations …

Complete Genome Sequence Of Thauera Aminoaromatica Strain Mz1t, Ke Jiang, John Sanseverino, Archana Chauhan, Susan Lucas, Alex Copeland, Alla Lapidus, Tijana Glavina Del Rio, Eileen Dalin, Hope Tice, David Bruce, Lynne Goodwin, Sam Pitluck, David Sims, Thomas Brettin, John C. Detter, Cliff Han, Y.J. Chang, Frank Larimer, Miriam Land, Loren Hauser, Nikos C. Kyrpides, Natalia Mikhailova, Scott Moser, Patricia Jegier, Dan Close, Jennifer M. Debruyn, Ying Wang, Alice C. Layton, Michael S. Allen, Gary S. Sayler

United States Department of Energy: Publications

Thauera aminoaromatica strain MZ1T, an isolate belonging to genus Thauera, of the family Rhodocyclaceae and the class the Betaproteobacteria, has been characterized for its ability to produce abundant exopolysaccharide and degrade various aromatic compounds with nitrate as an electron acceptor. These properties, if fully understood at the genome-sequence level, can aid in environmental processing of organic matter in anaerobic cycles by short-circuiting a central anaerobic metabolite, acetate, from microbiological conversion to methane, a critical greenhouse gas. Strain MZ1T is the first strain from the genus Thauera with a completely sequenced genome. The 4,496,212 bp chromosome and 78,374 bp plasmid …

The Crystal Structure Of The Extracellular 11-Heme Cytochromeundareveals A Conserved 10-Heme Motif And Defined Binding Site For Soluble Iron Chelates, Marcus J. Edwards, Andrea Hall, Liang Shi, James K. Fredrickson, John M. Zachara, Julea N. Butt, David J. Richardson, Thomas A. Clarke

United States Department of Energy: Publications

Members of the genus Shewanella translocate decaor undeca-heme cytochromes to the external cell surface thus enabling respiration using extracellular minerals and polynuclear Fe(III) chelates. The high resolution structure of the first undeca-heme outer membrane cytochrome, UndA, reveals a crossed heme chain with four potential electron ingress/ egress sites arranged within four domains. Sequence and structural alignment of UndA and the deca-heme MtrF reveals the extra heme of UndA is inserted between MtrF hemes 6 and 7. The remaining UndA hemes can be superposed over the heme chain of the decaheme MtrF, suggesting that a ten heme core is conserved between …

Three-Dimensional Bayesian Geostatistical Aquifer Characterization At The Hanford 300 Area Using Tracer Test Data, Xingyuan Chen, Haruko Murakami, Melanie S. Hahn, Glenn E. Hammond, Mark Rockhold, John M. Zachara, Yoram Rubin

United States Department of Energy: Publications

Tracer tests performed under natural or forced gradient flow conditions can provide useful information for characterizing subsurface properties, through monitoring, modeling, and interpretation of the tracer plume migration in an aquifer. Nonreactive tracer experiments were conducted at the Hanford 300 Area, along with constant-rate injection tests and electromagnetic borehole flow meter tests. A Bayesian data assimilation technique, the method of anchored distributions (MAD) (Rubin et al., 2010), was applied to assimilate the experimental tracer test data with the other types of data and to infer the three-dimensional heterogeneous structure of the hydraulic conductivity in the saturated zone of the Hanford …

Analysis Of Phase Separation In High Performance Pbte–Pbs Thermoelectric Materials, Steven N. Girard, Klaus Schmidt-Rohr, Thomas C. Chasapis, Euripides Hatzikraniotis, B. Njegic, E. M. Levin, A. Rawal, Konstantinos M. Paraskevopoulos, Mercouri G. Kanatzidis

United States Department of Energy: Publications

Phase immiscibility in PbTe–based thermoelectric materials is an effective means of top-down synthesis of nanostructured composites exhibiting low lattice thermal conductivities. PbTe_{1− x} S_x thermoelectric materials can be synthesized as metastable solid solution alloys through rapid quenching. Subsequent post-annealing induces phase separation at the nanometer scale, producing nanostructures that increase phonon scattering and reduce lattice thermal conductivity. However, there has yet to be any study investigating in detail the local chemical structure of both the solid solution and nanostructured variants of this material system. Herein, quenched and annealed (i.e., solid solution and phase-separated) samples of PbTe–PbS are analyzed …

Nanoscale Structure And Structural Relaxation In Zr50cu45al5 Bulk Metallic Glass, Jinwoo Hwang, Z. H. Melgarejo, Y. E. Kalay, I. Kalay, Matthew J. Kramer, D. S. Stone, P. M. Voyles

United States Department of Energy: Publications

Hybrid reverse Monte Carlo simulations of the structure of Zr₅₀Cu₄₅Al₅ bulk metallic glass incorporating medium-range structure from fluctuation electron microscopy data and short-range structure from an embedded atom potential produce structures with significant fractions of icosahedral- and crystal-like atomic clusters. Similar clusters group together into nanometer-scale regions, and relaxation transforms crystal-like clusters into icosahedral clusters. A model refined against only the potential does not agree with the fluctuation microscopy data and contains few crystal-like clusters.

Enhancement Of Thermopower Of Tags-85 High-Performance Thermoelectric Material By Doping With The Rare Earth Dy, E. M. Levin, S. L. Bud’Ko, K. Schmidt-Rohr

United States Department of Energy: Publications

Enhancement of thermopower is achieved by doping the narrow-band semiconductor Ag_6.52Sb_6.52Ge_36.96Te₅₀ (acronym TAGS-85), one of the best p -type thermoelectric materials, with 1 or 2% of the rare earth dysprosium (Dy). Evidence for the incorporation of Dy into the lattice is provided by X-ray diffraction and increased orientation-dependent local fields detected by ¹²⁵Te NMR spectroscopy. Since Dy has a stable electronic configuration, the enhancement cannot be attributed to 4f -electron states formed near the Fermi level. It is likely that the enhancement is due to a small reduction in the carrier …

Incorporating A Completely Renormalized Coupled Cluster Approach Into A Composite Method For Thermodynamic Properties And Reaction Paths, Sean A. Nedd, Nathan J. Deyonker, Angela K. Wilson, Mark S. Gordon, Piotr Piecuch

United States Department of Energy: Publications

The correlation consistent composite approach (ccCA), using the S4 complete basis set two-point extrapolation scheme (ccCA-S4), has been modified to incorporate the left-eigenstate completely renormalized coupled cluster method, including singles, doubles, and non-iterative triples (CR-CC(2,3)) as the highest level component. The new ccCA-CC(2,3) method predicts thermodynamic properties with an accuracy that is similar to that of the original ccCA-S4 method. At the same time, the inclusion of the single-reference CR-CC(2,3) approach provides a ccCA scheme that can correctly treat reaction pathways that contain certain classes of multi-reference species such as diradicals, which would normally need to be treated by more …

Experimental And Theoretical Electronic Structure Of Eurh2as2, A. D. Palczewski, R. S. Dhaka, Y. Lee, Yogesh Singh, D. C. Johnston, B. N. Harmon, Adam Kaminski

United States Department of Energy: Publications

The Fermi surfaces (FS’s) and band dispersions of EuRh₂As₂ have been investigated using angle-resolved photoemission spectroscopy. The results in the high-temperature paramagnetic state are in good agreement with the full-potential linearized augmented-plane-wave calculations, especially in the context of the shape of the two-dimensional FS’s and band dispersion around the Γ (0,0) and X (π,π) points. Interesting changes in band folding are predicted by the theoretical calculations below the magnetic transition temperature T_N ≈ 47 K. However, by comparing the FS’s measured at 60 and 40 K, we did not observe any signature of this transition at …

Magnetic And Structural Transitions In The Iron-Chalcogenide High-Tc Superconductor: K0.8fe1.76se2.00, W. N. Rowan-Weetaluktuk, D. H. Ryan, J. M. Cadogan, R. Hu, S. L. Bud’Ko, Paul C. Canfield

United States Department of Energy: Publications

⁵⁷Fe Mössbauer spectroscopy was used to study single-crystals of K_0.8Fe_1.76Se_2.00 from 6K to 673 K. At 6 K, the hyperfine field (B_hf) is canted away from the c-axis by 18±3°. The temperature dependence of B_hf follows a spin wave model with a spin excitation gap of 9±1 meV. A sudden increase in the line width and a corresponding drop in (1/2)eQV_zz at T_N = 532 K are indications of strong coupling between the magnetic and structural transitions.