Bioresource and Agricultural Engineering Commons^™

“Strategically Locating Soybean And Biodiesel Processing Facilities In Nebraska”, Lori Luebbe

Industrial Agricultural Products Center: Publications and Information

Is the production of biodiesel feasible in Nebraska? A standard answer depends on the business operating condition. More specifically, a statewide, as opposed to a site specific, study conducted by the Independent Biodiesel Feasibility Group (IBFG) in July 2005 for the Nebraska Soybean Association (NSA) concluded a positive return on equity could be expected. At that time, the return was estimated to be poor for the small scale, 5 million gallons per year (MGPY) scenario analyzed and only modest for the mid, 15 MGPY, and larger scale, 30 MGPY scenarios. For a complete copy of the feasibility study, contact the …

“Strategically Locating Soybean And Biodiesel Processing Facilities In Nebraska”, Lori Luebbe, Milford Hanna, Loren Isom, Robert Weber, Zach Schroeder, Richard Sanne, Mark Harris, Victor Bohuslavsky, Todd Sneller, Brian Wilcox

Industrial Agricultural Products Center: Publications and Information

Is the production of biodiesel feasible in Nebraska? A standard answer depends on the business operating condition. More specifically, a statewide, as opposed to a site specific, study conducted by the Independent Biodiesel Feasibility Group (IBFG) in July 2005 for the Nebraska Soybean Association (NSA) concluded a positive return on equity could be expected. At that time, the return was estimated to be poor for the small scale, 5 million gallons per year (MGPY) scenario analyzed and only modest for the mid, 15 MGPY, and larger scale, 30 MGPY scenarios. For a complete copy of the feasibility study, contact the …

Development Of An Electro-Mechanical System To Identify & Map Adverse Soil Compaction Using Gis&Gps, Santosh Pitla, L. G. Wells

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

A stand-alone electro-mechanical system with a 32-inch disc coulter was developed and tested to identify soil compaction in a 1-acre field located at the University of Kentucky Animal Research Center (UKARC). The system was evaluated by making four passes in the square grid cell. With the aid of hydraulic actuation, the coulter oscillated between depths of 100mm (4-in) and 330mm (13-in) as it moved forward and recorded the vertical impedance force given by the soil continuously. Forty standard soil cone penetrometer measurements along the diagonals to a depth of 400mm (16-in) were taken and the average cone indices (MPa) at …

Risk Of Colon Cancer In Hereditary Non-Polyposis Colorectal Cancer Patients As Predicted By Fuzzy Modeling: Influence Of Smoking, Rhonda M. Brand, David D. Jones, Henry T. Lynch, Randall E. Brand, Patrice Watson, Ramesh Ashwathnayaran, Hemant K. Roy

Department of Agricultural and Biological Systems Engineering: Faculty Publications

AIM: To investigate whether a fuzzy logic model could predict colorectal cancer (CRC) risk engendered by smoking in hereditary non-polyposis colorectal cancer (HNPCC) patients.

METHODS: Three hundred and forty HNPCC mismatch repair (MMR) mutation carriers from the Creighton University Hereditary Cancer Institute Registry were selected for modeling. Age-dependent curves were generated to elucidate the joint effects between gene mutation (hMLH1 or hMSH2), gender, and smoking status on the probability of developing CRC.

RESULTS: Smoking significantly increased CRC risk in male hMSH2 mutation carriers (P < 0.05). hMLH1 mutations augmented CRC risk relative to hMSH2 mutation carriers for males (P < 0.05). Males had a significantly higher risk of CRC than females for hMLH1 non smokers (P < 0.05), hMLH1 smokers (P < 0.1) and hMSH2 smokers (P < 0.1). Smoking promoted CRC in a dose-dependent manner in hMSH2 in males (P < 0.05). Females with hMSH2 mutations and both sexes with the hMLH1 groups only demonstrated a smoking effect after an extensive smoking history (P < 0.05).

CONCLUSION: CRC promotion by smoking in HNPCC patients is dependent on gene mutation, gender and age. …

Trees And Ice Storms: The Development Of Ice Storm–Resistant Urban Tree Populations (Second Edition), Richard J. Hauer, Jeffrey O. Dawson, Les P. Werner

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

Severe ice storms occur every year in the United States and Canada, particularly in the midwestern and eastern regions of the United States. Along with fires and wind, ice storms are a frequent and major natural disturbance factor in eastern deciduous forests. Likewise ice storms are responsible for deaths and injuries of people and cause dramatic damage and tree loss to urban forests. Ice storms annually result in millions of dollars in loss, and potentially billions of dollars in losses for extreme and widespread ice storms. Damage to electric distribution systems, blocked roadways, and property damage from fallen trees and …

Microscopic Reactive Diffusion Of Uranium In The Contaminated Sediments At Hanford, United States, Chongxuan Liu, John M. Zachara, Wassana Yantasee, Paul D. Majors, James Mckinley

United States Department of Energy: Publications

Microscopic and spectroscopic analyses of uranium-contaminated sediments from select locations at the U.S. Department of Energy (DOE) Hanford site have revealed that sorbed uranium (U) often exists as uranyl precipitates associated with intragrain fractures of granitic clasts. The release of U to contacting fluids appears to be controlled by intragrain ion diffusion coupled with the dissolution kinetics of the precipitates that exist in the form of Na-boltwoodite. Here we present a coupled microscopic reactive diffusion model for the contaminated sediment on the basis of experimental measurements of intragrain diffusivity in the granitic lithic fragments and the dissolution kinetics of synthetic …

Morphology And Tensile Properties Of Multigraft Copolymers With Regularly Spaced Tri-, Tetra-, And Hexafunctional Junction Points, Yuqing Zhu, Engin Burgaz, Samuel P. Gido, Ulrike Staudinger, Roland Weidisch, David Uhrig, Jimmy W. Mays

United States Department of Energy: Publications

The effect of chain architecture on the morphological and tensile properties of series of multigraft copolymers, with regularly spaced tri-, tetra-, and hexafunctional junction points, was investigated using transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS), and tensile testing. The materials were synthesized by coupling difunctional polyisoprene (PI) spacers and living polystyrene (PS) branches, made by anionic polymerization, with chlorosilanes of different functionalities. Since the coupling process is a step-growth polymerization, yielding polydisperse products, fractionation was utilized to separate each material into three fractions (high, middle, and low molecular weight), each of low polydispersity. All three fractions have the same …

Well-Defined Poly(4-Vinylbenzocyclobutene): Synthesis By Living Anionic Polymerization And Characterization, Georgios Sakellariou, Durairaj Baskaran, Nikos Hadjichristidis, Jimmy W. Mays

United States Department of Energy: Publications

Living anionic polymerization of 4-vinylbenzocylobutene was performed in benzene at room temperature using sec-butyllithium as the initiator. Results of the kinetic studies indicated the termination- and transfer-free nature of the polymerization. Homopolymers with predictable molecular weights and narrow molecular weight distributions were produced, excluding the interference of the cyclobutene rings during initiation and propagation. Thermogravimetric analysis of poly(4-vinylbenzocyclobutene) in air showed a small weight gain at ~200 °C, a rapid decomposition at ~455 °C, and a gradual decomposition at ~566 °C. This behavior was attributed to the formation of radicals from the pendent benzocyclobutene functionality through o-quinodimethane intermediates and …

Reductive Biotransformation Of Fe In Shale–Limestone Saprolite Containing Fe(Iii) Oxides And Fe(Ii)/Fe(Iii) Phyllosilicates, Ravi K. Kukkadapu, John M. Zachara, James K. Fredrickson, James P. Mckinley, David W. Kennedy, Steven C. Smith, Hailiang Dong

United States Department of Energy: Publications

A <2.0-mm fraction of a mineralogically complex subsurface sediment containing goethite and Fe(II)/Fe(III) phyllosilicates was incubated with Shewanella putrefaciens (strain CN32) and lactate at circumneutral pH under anoxic conditions to investigate electron acceptor preference and the nature of the resulting biogenic Fe(II) fraction. Anthraquinone-2,6-disulfonate (AQDS), an electron shuttle, was included in select treatments to enhance bioreduction and subsequent biomineralization. The sediment was highly aggregated and contained two distinct clast populations: (i) a highly weathered one with ‘‘sponge-like’’ internal porosity, large mineral crystallites, and Fecontaining micas, and (ii) a dense, compact one with fine-textured Fe-containing illite and nano-sized goethite, as revealed by various forms of electron microscopic analyses. Approximately 10–15% of the Fe(III)_TOT was bioreduced by …

Kinetics Of Microbial Reduction Of Solid Phase U(Vi), Chongxuan Liu, Byong-Hun Jeon, John M. Zachara, Zheming Wang, Alice Dohnalkova, James K. Fredrickson

United States Department of Energy: Publications

Sodium boltwoodite (NaUO₂SiO₃OH•1.5 H₂O) was used to assess the kinetics of microbial reduction of solid-phase U(VI) by a dissimilatory metal-reducing bacterium (DMRB), Shewanella oneidensis strain MR-1. The bioreduction kinetics was studied with Na-boltwoodite in suspension or within alginate beads in a nongrowth medium with lactate as electron donor at pH 6.8 buffered with PIPES. Concentrations of U(VI)_tot and cell number were varied to evaluate the coupling of U(VI) dissolution, diffusion, and microbial activity. Microscopic and spectroscopic analyses with transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and laser-induced fluorescence spectroscopy (LIFS) collectively indicated …

The Effect Of Calcium On Aqueous Uranium(Vi) Speciation And Adsorption To Ferrihydrite And Quartz, Patricia M. Fox, James A. Davis, John M. Zachara

United States Department of Energy: Publications

Recent studies of uranium (VI) geochemistry have focused on the potentially important role of the aqueous species, CaUO₂(CO₃)₃²⁻ and Ca₂UO₂(CO₃)₃⁰(aq), on inhibition of microbial reduction and uranium(VI) aqueous speciation in contaminated groundwater. However, to our knowledge, there have been no direct studies of the effects of these species on U(VI) adsorption by mineral phases. The sorption of U(VI) on quartz and ferrihydrite was investigated in NaNO₃ solutions equilibrated with either ambient air (430 ppm CO₂) or 2% CO₂ in the presence …

Microscale Controls On The Fate Of Contaminant Uranium In The Vadose Zone, Hanford Site, Washington, James Mckinley, John M. Zachara, Chongxuan Liu, Steven M. Heald, Brenda Prenitzer, Brian W. Kempshall

United States Department of Energy: Publications

An alkaline brine containing uranyl (UO₂²⁺) leaked to the thick unsaturated zone at the Hanford Site. We examined samples from this zone at microscopic scale to determine the mode of uranium occurrence—microprecipitates of uranyl (UO₂²⁺) silicate within lithic-clast microfractures—and constructed a conceptual model for its emplacement, which we tested using a model of reactive diffusion at that scale. The study was driven by the need to understand the heterogeneous distribution of uranium and the chemical processes that controlled it. X-ray and electron microprobe imaging showed that the uranium was associated with a minority …

Isolation Of A High-Affinity Functional Protein Complex Between Omca And Mtrc: Two Outer Membrane Decaheme C-Type Cytochromes Of Shewanella Oneidensis Mr-1, Liang Shi, Baowei Chen, Zheming Wang, Dwayne A. Elias, M. Uljana Mayer, Yuri Gorby, Shuison Ni, Brian Lower, David Kennedy, David S. Wunschel, Heather M. Mottaz, Matthew Marshall, Eric Hill, Alexander Beliaev, John M. Zachara, James K. Fredrickson, Thomas Squier

United States Department of Energy: Publications

Shewanella oneidensis MR-1 is a facultatively anaerobic bacterium capable of using soluble and insoluble forms of manganese [Mn(III/IV)] and iron [Fe(III)] as terminal electron acceptors during anaerobic respiration. To assess the structural association of two outer membrane-associated c-type decaheme cytochromes (i.e., OmcA [SO1779] and MtrC [SO1778]) and their ability to reduce soluble Fe(III)-nitrilotriacetic acid (NTA), we expressed these proteins with a C-terminal tag in wild-type S. oneidensis and a mutant deficient in these genes (i.e., ∆omcA mtrC). Endogenous MtrC copurified with tagged OmcA in wild-type Shewanella, suggesting a direct association. To further evaluate their possible interaction, …

Absolute Photoionization Cross Sections For Xe4+, Xe5+, And Xe6+ Near 13.5 Nm: Experiment And Theory, A. Aguilar, J. D. Gillaspy, G. F. Gribakin, R. A. Phaneuf, M. F. Gharaibeh, M. G. Kozlov, J. D. Bozek, A. L. D. Kilcoyne

United States Department of Energy: Publications

Absolute photoionization cross-section measurements for a mixture of ground and metastable states of Xe⁴⁺, Xe⁵⁺, and Xe⁶⁺ are reported in the photon energy range of 4d→nf transitions, which occur within or adjacent to the 13.5 nm window for extreme ultraviolet lithography light source development. The reported values allow the quantification of opacity effects in xenon plasmas due to these 4d→nf autoionizing states. The oscillator strengths for the 4d→4f and 4d→5f transitions in Xe^q+ (q=1–6) ions are calculated using nonrelativistic Hartree-Fock …

Resonant Soft X-Ray Scattering From Structured Polymer Nanoparticles, Tohru Araki, Harald Ade, Jeffrey M. Stubbs, Donald C. Sundberg, Gary E. Mitchell, Jeffrey B. Kortright, A. L. D. Kilcoyne

United States Department of Energy: Publications

The application of resonant soft x-ray scattering to chemically heterogeneous soft condensed matter materials is presented. Two structured styrene-acrylic polymer composite latex particles ~230 nm in diameter were utilized to delineate the potential utility of this technique. Angular scans at photon energies corresponding to strong scattering contrast between specific chemical moieties made it possible to infer the effective radii that correspond to the two polymer phases in the nanoparticles. The results show that resonant soft x-ray scattering should be a powerful complementary tool to neutron and hard x-ray scattering for the characterization of structured soft condensed matter nanomaterials.

Synchronous Photoinjection Using A Frequency-Doubled Gain-Switched Fiber-Coupled Seed Laser And Eryb-Doped Fiber Amplifier, J. Hansknecht, M. Poelker

United States Department of Energy: Publications

Light at 1560 nm from a gain-switched fiber-coupled diode laser and ErYb-doped fiber amplifier was frequency doubled to obtain over 2 Waverage power at 780 nm with ~40 ps pulses and pulse repetition rate of 499 MHz. This light was used to drive the 100 kV DC high voltage GaAs photoemission gun at the Continuous Electron Beam Accelerator Facility at Jefferson Laboratory to produce a high average current beam (100 μA) of highly spin-polarized electrons ( > 80%). This new drive-laser system represents a significant advance over laser systems used previously, providing significantly higher power and enhanced reliability.

Photoionization And Electron-Impact Ionization Of Kr5+, M. Lu, M. F. Gharaibeh, G. Alna’Washi, R. A. Phaneuf, A. L. D. Kilcoyne, E. Levenson, A. S. Schlachter, A. M. Müller, S. Schippers, J. Jacobi, S. W. J. Scully, C. Cisneros

United States Department of Energy: Publications

Absolute photoionization cross sections for Kr⁵⁺ were measured in the photon energy range 74–175 eV using synchrotron radiation. For comparison, a detailed energy scan of the electron-impact ionization cross section was made in the same energy range and normalized to previously published absolute measurements. The Flexible Atomic Code and Cowan atomic structure code were used to calculate energy levels, excitation energies, and oscillator strengths for 3d→np, 3d→nf, and 4s→np autoionizing transitions from the ground and metastable states. Within the experimental uncertainty, oscillator strengths determined from the photoionization measurements are …

Photoionization And Electron-Impact Ionization Of Kr3+, M. Lu, G. Alna’Washi, M. Habibi, M. F. Gharaibeh, R. A. Phaneuf, A. L. D. Kilcoyne, E. Levenson, A. S. Schlachter, C. Cisneros, G. Hinojosa

United States Department of Energy: Publications

Absolute photoionization cross sections for Kr³⁺ were measured in the energy range 39.05–143.2 eV for single ionization and 120.6–137.7 eV for double ionization. For comparison, an electron-impact singleionization measurement was made in the energy range 43.1–179.1 eV and normalized to previously published absolute measurements. The Flexible Atomic Code and Cowan atomic structure codes were used to calculate energy levels, excitation energies and oscillator strengths for 3d→np, 3d→nf, and 4s→np autoionizing transitions from the ground and metastable states. From the single-photoionization measurements, ionization thresholds of the ²P^{o …}

Differences Between Tethered Polyelectrolyte Chains On Bare Mica And Hydrophobically Modified Mica, Marc Balastre, Phillip Schorr, J.-F. Argillier, Jinchuan Yang, Jimmy W. Mays, Matthew Tirrell

United States Department of Energy: Publications

This study investigates the structures of layers of amphiphilic diblock copolymers of poly(t-butyl styrene)-poly- (styrene sulfonate) (PtBS-PSS) adsorbed on both the bare mica surface (hydrophilic) and an octadecyltriethoxysilane (OTE)-modified mica surface (hydrophobic). When the surface is rendered hydrophobic, the nonsoluble block exhibits stronger interaction with the surface and higher adsorbed masses are achieved. Interaction forces between two such adsorbed layers on both substrates were measured using the surface forces apparatus. The effect of salt concentration (Cs) and molecular weight (N) on the height of the self-assembled layers (L₀) was examined in each case. The resulting scaling relationship is …

Changes In Uranium Speciation Through A Depth Sequence Of Contaminated Hanford Sediments, Jeffrey Catalano, James Mckinley, John M. Zachara, Steve Heald, Steven Smith, Gordon Brown Jr.

United States Department of Energy: Publications

The disposal of basic sodium aluminate and acidic U(VI)-Cu(II) wastes in the now-dry North and South 300 A Process Ponds at the Hanford site resulted in a groundwater plume of U(VI). To gain insight into the geochemical processes that occurred during waste disposal and those affecting the current and future fate and transport of this uranium plume, the solid-phase speciation of uranium in a depth sequence of sediments from the base of the North Process Pond through the vadose zone to groundwater was investigated using standard chemical and mineralogical analyses, electron and X-ray microprobe measurements, and X-ray absorption fine structure …

Modeling Selected Properties Of Extruded Rice Flour And Rice Starch By Neural Networks And Statistics, G. Ganjyal, Milford A. Hanna, P. Supprung, A. Noomhorm, David D. Jones

Industrial Agricultural Products Center: Publications and Information

Rice flour and rice starch were single-screw extruded and selected product properties were determined. Neural network (NN) models were developed for prediction of individual product properties, which performed better than the regression models. Multiple input and multiple output (MIMO) models were developed to simultaneously predict five product properties or three product properties from three input parameters; they were extremely efficient in predictions with values of R² > 0.95. All models were feed-forward backpropagation NN with three-layered networks with logistic activation function for the hidden layer and the output layers. Also, model parameters were very similar except for the number of …

Photoionization Of Xenon Clusters, John D. Bozek, Bruce S. Rude, A. L. D. Kilcoyne

United States Department of Energy: Publications

High resolution photoelectron spectra of xenon clusters of about 100 atoms, measured with photon energies of 20 to 60 eV are reported. Peaks due to the clusters are observed at lower binding energies than the corresponding atomic lines and exhibit different behaviors. The peak associated with the Xe 5p_1/2 state at higher binding energy is relatively unchanged with photon energy whereas the Xe 5p_3/2 peak changes its shape with increasing photon energy. The change is attributed to differences in the escape depth of the electrons at different kinetic energies and the bulk and surface components of the cluster.

Solution Properties Of 1,3-Cyclohexadiene Polymers By Laser Light Scattering And Small-Angle Neutron Scattering, Seok I. Yun, Ken Terao, Kunlun Hong, Yuri B. Melnichenko, George D. Wignall, Jimmy W. Mays, Phillip F. Britt

United States Department of Energy: Publications

1,3-Cyclohexdiene polymers (PCHD) and their derivatives are of interest due to the six-member rings in the main chain, which are expected to impart higher mechanical strength and better thermal and chemical stability, as compared to common vinyl polymers. For example, hydrogenated PCHD has the highest glass transition temperature (t_g ~ 231 °C) of all hydrocarbon polymers, and it also shows good heat, weather, impact, abrasion, and chemical resistance as well as low water absorption. In addition, PCHD has unique photochemical properties, such as excellent transparency, due to the isolated double bonds in the main chain. Also, block copolymers …

Looped Polymer Brushes Formed By Self-Assembly Of Poly(2-Vinylpyridine)-Polystyrene-Poly(2-Vinylpyridine) Triblock Copolymers At The Solid-Fluid Interface. Kinetics Of Preferential Adsorption, Jose Alonzo, Zhenyu Huang, Ming Liu, Jimmy W. Mays, Ryan G. Toomey, Mark D. Dadmun, S. Michael Kilbey, Ii

United States Department of Energy: Publications

The kinetics of assembly of a series of poly(2-vinylpyridine)-polystyrene-poly(2-vinylpyridine) (PVP-b-PS-b-PVP) triblock copolymers from the selective solvent toluene onto a silicon surface has been studied using phase-modulated ellipsometry. The adsorbed amount and thickness have been determined independently as functions of time. Even though the adsorbed amount as a function of time follows the traditional two-step process that is typical of the self-assembly of diblock copolymerssthere is an initial fast adsorption followed by a slow buildup of the layer (brush regime) - the thickness shows an “overshoot” that corresponds to the brush regime. We attribute this phenomenon, not …

Microbial Reduction Of Fe(Iii) In The Fithian And Muloorina Illites: Contrasting Extents And Rates Of Bioreduction, Jennifer L. Seabaugh, Hailiang Dong, Ravi K. Kukkadapu, Dennis D. Eberl, John P. Morton, Jinwook Kim

United States Department of Energy: Publications

Shewanella putrefaciens CN32 reduces Fe(III) within two illites which have different properties: the Fithian bulk fraction and the <0.2 mm fraction of Muloorina. The Fithian illite contained 4.6% (w/w) total Fe, 81% of which was Fe(III). It was dominated by illite with some jarosite (~32% of the total Fe(III)) and goethite (11% of the total Fe(III)). The Muloorina illite was pure and contained 9.2% Fe, 93% of which was Fe(III). Illite suspensions were buffered at pH 7 and were inoculated with CN32 cells with lactate as the electron donor. Select treatments included anthraquinone-2,6-disulfonate (AQDS) as an electron shuttle. Bioproduction of Fe(II) was determined by ferrozine analysis. The unreduced and bioreduced solids were characterized by Mossbauer spectroscopy, X-ray diffraction and transmission electron microscopy. The extent of Fe(III) reduction in the bulk Fithian illite was enhanced by the presence of AQDS (73%) with complete reduction of jarosite and goethite and partial reduction of illite. Mossbauer spectroscopy and chemical extraction determined that 21ÿ25% of illite-associated Fe(III) was bioreduced. The extent of bioreduction was less in the absence of AQDS (63%) and only jarosite was completely reduced with partial reduction of goethite and illite. The XRD and TEM data revealed no significant illite dissolution or biogenic minerals, suggesting that illite was reduced in the solid state and biogenic Fe(II) from jarosite and goethite was either released to aqueous solution or adsorbed onto residual solid surfaces. In contrast, only 1% of the structural Fe(III) in Muloorina illite was bioreduced. The difference in the extent and rate of bioreduction between the two illites was probably due to the difference in layer charge and the total structural Fe content between the Fithian illite (0.56 per formula) and Muloorina illite (0.87). There may be other factors contributing to the observed differences, such as expandability, surface area and the arrangements of Fe in the octahedral sheets. The results of this study have important implications for predicting microbe-induced physical and chemical changes of clay minerals in soils and sediments.

Adsorption Of Uranyl On Gibbsite: A Time-Resolved Laser-Induced Fluorescence Spectroscopy Study, Hyun-Shik Chang, Gregory Korshin, Zheming Wang, John M. Zachara

United States Department of Energy: Publications

Uranyl adsorbed on gibbsite at pH 4.0-8.0 and ionic strengths (ISs) 0.001-0.4 M (NaClO₄) in the absence of carbonate was studied using time-resolved laser-induced fluorescence spectroscopy (TRLIFS) under cryogenic conditions. TRLIFS data showed the presence of several distinct emission components. Their contributions were determined using the evolving factor analysis approach. Four components denoted as species A, B, C, and D were discerned. Each of them was characterized by a characteristic response to pH and IS changes and also by a unique combination of the values of the fundamental transition energyE_0,0, vibronic spacing ∆E, and half-width …

The Dissolution Of Synthetic Na-Boltwoodite In Sodium Carbonate Solutions, Eugene S. Ilton, Chongxuan Liu, Wassana Yantasee, Zheming Wang, Dean A. Moore, Andrew R. Felmy, John M. Zachara

United States Department of Energy: Publications

Uranyl silicates such as uranophane and Na-boltwoodite appear to control the solubility of uranium in certain contaminated sediments at the US Department of Energy Hanford site [Liu, C., Zachara, J.M., Qafoku, O., McKinley, J.P., Heald, S.M., Wang, Z. 2004. Dissolution of uranyl microprecipitates in subsurface sediments at Hanford Site, USA. Geochim. Cosmochim. Acta 68, 4519– 4537.]. Consequently, the solubility of synthetic Na-boltwoodite, Na(UO₂)(SiO₃OH) • 1.5H₂O, was determined over a wide range of bicarbonate concentrations, from circumneutral to alkaline pH, that are representative of porewater and groundwater compositions at the Hanford site and …

C-Type Cytochrome-Dependent Formation Of U(Iv) Nanoparticles By Shewanella Oneidensis, Matthew J. Marshall, Alexander Beliaev, Alice Dohnalkova, David Kennedy, Liang Shi, Zheming Wang, Maxim Boyanov, Barry Lai, Kenneth M. Kemner, Jeffrey Mclean, Samantha Reed, David Culley, Vanessa L. Bailey, Cody Simonson, Daad A. Saffarini, Margaret Romine, John M. Zachara, James K. Fredrickson

United States Department of Energy: Publications

Modern approaches for bioremediation of radionuclide contaminated environments are based on the ability of microorganisms to effectively catalyze changes in the oxidation states of metals that in turn influence their solubility. Although microbial metal reduction has been identified as an effective means for immobilizing highly-soluble uranium(VI) complexes in situ, the biomolecular mechanisms of U(VI) reduction are not well understood. Here, we show that c-type cytochromes of a dissimilatory metal-reducing bacterium, Shewanella oneidensis MR-1, are essential for the reduction of U(VI) and formation of extracelluar UO₂ nanoparticles. In particular, the outer membrane (OM) decaheme cytochrome MtrC (metal reduction), previously implicated …

Speciation And Quantitative Mapping Of Metal Species In Microbial Biofilms Using Scanning Transmission X-Ray Microscopy, James J. Dynes, Tolek Tyliszczak, Tohru Araki, John R. Lawrence, George D. W. Swerhone, Gary G. Leppard, Adam P. Hitchcock

United States Department of Energy: Publications

A scanning transmission X-ray microscope illuminated with synchrotron light was used to investigate the speciation and spatial distributions of metals in a microbial biofilm cultivated from river water. Metal 2p absorption edge signals were used to provide metal speciation (through shapes of the absorption spectra) and quantitative spatial distributions of the metal species. This paper presents sample data and describes methods for extracting quantitative maps of metal species from image sequences recorded in the region of the metal 2p edges. Comparisons were made with biochemical characterization of the same region using images recorded at the C 1s and O 1s …

Nonintrusive Mapping Of Near-Surface Preferential Flow, R. S. Freeland, Lameck O. Odhiambo, J. S. Tyner, J. T. Ammons, W. C. Wright

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A unique survey protocol has been developed that maps near-subsurface preferential flow using integrated ground-penetrating radar (GPR) and a differential geographical positioning system (DGPS). The survey protocol consists of a mobile GPR system that spirals outward along a prescribed course, continuously gathering subsurface data for an extended period. Metered water is applied to a centrally located water-ponding ring, after first capturing the initial dry-state pattern signatures. The water radiates outward beneath the surface as it follows preferential flow pathways, which the GPR instrumentation spiraling above highlights. After data are collected, pre- and post-water time-elapsed images profiles are segmented by pattern …