Bioresource and Agricultural Engineering Commons^™

Development Of High-Temperature Ferromagnetism In Sno2 And Paramagnetism In Sno By Fe Doping, A. Punnoose, J. Hays, A. Thurber, M. H. Engelhard, Ravi K. Kukkadapu, C. Wang, V. Shutthanandan, S. Thevuthasan

United States Department of Energy: Publications

We report the development of room-temperature ferromagnetism in chemically synthesized powder samples of Sn_1−xFe_xO₂ (0.005≤ x ≤0.05) and paramagnetic behavior in an identically synthesized set of Sn_1−xFe_xO. The ferromagnetic Sn_0.99Fe_0.01O₂ showed a Curie temperature T_C=850 K, which is among the highest reported for transition-metal-doped semiconductor oxides. With increasing Fe doping, the lattice parameters of SnO₂ decreased and the saturation magnetization increased, suggesting a strong structure-magnetic property relationship. When the Sn_0.95Fe_0.05O₂ was prepared at different temperatures between …

Influence Of Calcite And Dissolved Calcium On Uranium(Vi) Sorption To A Hanford Subsurface Sediment, Wenming Dong, William Ball, Chongxuan Liu, Zheming Wang, Alan Stone, Jing Bai, John M. Zachara

United States Department of Energy: Publications

The influence of calcite and dissolved calcium on U(VI) adsorption was investigated using a calcite-containing sandy silt/clay sediment from the U. S. Department of Energy Hanford site. U(VI) adsorption to sediment, treated sediment, and sediment size fractions was studied in solutions that both had and had not been preequilibrated with calcite, at initial [U(VI)] ) 10^-7-10^-5 mol/L and final pH ) 6.0- 10.0. Kinetic and reversibility studies (pH 8.4) showed rapid sorption (30 min), with reasonable reversibility in the 3-day reaction time. Sorption from solutions equilibrated with calcite showed maximum U(VI) adsorption at pH 8.4 ± 0.1. …

Influence Of Sediment Bioreduction And Reoxidation On Uranium Sorption, Chongxuan Liu, John M. Zachara, Lirong Zhong, Ravi K. Kukkadapu, Jim Szecsody, Dave Kennedy

United States Department of Energy: Publications

The influence of sediment bioreduction and reoxidation on U(VI) sorption was studied using Fe(III) oxide-containing saprolite from the U.S. Department of Energy (DOE) Oak Ridge site. Bioreduced sediments were generated by anoxic incubation with a metal-reducing bacterium, Shewanella putrefaciens strain CN32, supplied with lactate as an electron donor. The reduced sediments were subsequently reoxidized by air contact. U(VI) sorption was studied in Na- NO₃-HCO₃ electrolytes that were both closed and open to atmosphere and where pH, U(VI), and carbonate concentration were varied. Mössbauer spectroscopy and chemical analyses showed that 50% of the Fe(III)- oxides were reduced to …

Fluorescence Spectroscopy Of U(Vi)-Silicates And U(Vi)-Contaminated Hanford Sediment, Zheming Wang, John M. Zachara, Paul Gassman, Chongxuan Liu, Odeta Qafoku, Wassana Yantasee, Jeff Catalano

United States Department of Energy: Publications

Time-resolved U(VI) laser fluorescence spectra (TRLFS) were recorded for a series of natural uranium-silicate minerals including boltwoodite, uranophane, soddyite, kasolite, sklodowskite, cuprosklodowskite, haiweeite, and weeksite, a synthetic boltwoodite, and four U(VI)-contaminated Hanford vadose zone sediments. Lowering the sample temperature from RT to ~5.5 K significantly enhanced the fluorescence intensity and spectral resolution of both the minerals and sediments, offering improved possibilities for identifying uranyl species in environmental samples. At 5.5 K, all of the uranyl silicates showed unique, well-resolved fluorescence spectra. The symmetric O = U = O stretching frequency, as determined from the peak spacing of the vibronic bands …

Oxidative Remobilization Of Biogenic Uranium(Iv) Precipitates: Effects Of Iron(Ii) And Ph, Lirong Zhong, Chongxuan Liu, John M. Zachara, David Kennedy, James E. Szecsody, Brian Wood

United States Department of Energy: Publications

The oxidative remobilization of uranium from biogenic U(IV) precipitates was investigated in bioreduced sediment suspensions in contact with atmospheric O2 with an emphasis on the influence of Fe(II) and pH on the rate and extent of U release from the solid to the aqueous phase. The sediment was collected from the U.S. Department of Energy Field Research Center (FRC) site at Oak Ridge, Tennessee. Biogenic U(IV) precipitates and bioreduced sediment were generated through anaerobic incubation with a dissimilatory metal reducing bacterium Shewanella putrefaciens strain CN32. The oxidative remobilization of freshly prepared and 1-yr aged biogenic U(IV) was conducted in 0.1 …

Enzymology Of Electron Transport: Energy Generation With Geochemical Consequences, Thomas J. Dichristina, James K. Fredrickson, John M. Zachara

United States Department of Energy: Publications

Dissimilatory metal-reducing bacteria (DMRB) are important components of the microbial community residing in redox-stratified freshwater and marine environments. DMRB occupy a central position in the biogeochemical cycles of metals, metalloids and radionuclides, and serve as catalysts for a variety of other environmentally important processes including biomineralization, biocorrosion, bioremediation and mediators of ground water quality. DMRB are presented, however, with a unique physiological challenge: they are required to respire anaerobically on terminal electron acceptors which are either highly insoluble (e.g., Fe(III)- and Mn(IV)-oxides) and reduced to soluble end-products or highly soluble (e.g., U(VI) and Tc(VII)) and reduced to insoluble end-products. To …

Photoionization And Electron-Impact Ionization Of Xe3+, E. D. Emmons, A. Aguilar, M. F. Gharaibeh, S. W. J. Scully, R. A. Phaneuf, A. L. D. Kilcoyne, A. S. Schlachter, I. Álvarez, C. Cisneros, G. Hinojosa

United States Department of Energy: Publications

Photoionization and electron-impact ionization of Xe³⁺ ions in the region of 4d inner-shell excitation autoionization have been studied using interacting-beam spectroscopic techniques. Absolute cross sections for photoionization of Xe³⁺ have been obtained and the electron-impact spectrum has been normalized to previously published absolute data. The Xe³⁺ spectra show large contributions from 4d→nf excitation autoionization processes compared to the lower charge states of Xe due to the significant collapse of the nf wave functions into the ion core as the initial charge state of the ion is increased. In addition, a tentative value for …

Chemical Mapping Of Polymer Photoresists By Scanning Transmission X-Ray Microscopy, Ligia Muntean, Romain Planques, A. L. D. Kilcoyne, Stephen R. Leone, Mary Gilles, William D. Hinsberg

United States Department of Energy: Publications

Scanning transmission x-ray microscopy (STXM) is shown to be a powerful imaging technique that provides chemical selectivity and high spatial resolution (~35 nm) for studying chemically amplified photoresists. Samples of poly (4-t-butoxycarbonyloxystyrene) PTBOCST resist, imprinted by deep ultraviolet lithography with a line/space pattern of 1.10 μm/ 0.87 μm followed by a post-exposure bake, are used to demonstrate STXM imaging capabilities to extract photoresist latent images. Chemical contrast is obtained by measuring the x-ray absorption at an energy of 290.5 eV, corresponding to a carbon K shell electronic transition to the unoccupied π^* molecular orbital of the PTBOCST …

Photoionization Of Multiply Charged Ions At The Advanced Light Source, A. S. Schlachter, A. L. D. Kilcoyne, A. Aguilar, M. F. Gharaibeh, E. D. Emmons, S. W. J. Scully, R. A. Phaneuf, A. M. Müller, S. Schippers, I. Alvarez, C. Cisneros, G. Hinojosa, B. M. Mclaughlin

United States Department of Energy: Publications

Photoionization of multiply charged ions is studied using the merged-beams technique at the Advanced Light Source. An ion beam is created using a compact 10-GHz all-permanent-magnet ECR ion source and is accelerated with a small accelerator. The ion beam is merged with a photon beam from an undulator to allow interaction over an extended path. Absolute photoionization cross sections have been measured for a variety of ions along both isoelectronic and isonuclear sequences.

Photoexcitation Of A Volume Plasmon In C60 Ions, S. W. J. Scully, E. D. Emmons, M. F. Gharaibeh, R. A. Phaneuf, A. L. D. Kilcoyne, A. S. Schlachter, S. Schippers, A. M. Müller, H. S. Chakraborty, M. E. Madjet, J. M. Rost

United States Department of Energy: Publications

Neutral C₆₀ is well known to exhibit a giant resonance in its photon absorption spectrum near 20 eV. This is associated with a surface plasmon, where delocalized electrons oscillate as a whole relative to the ionic cage. Absolute photoionization cross-section measurements for C⁺₆₀, C²⁺₆₀, and C³⁺₆₀ ions in the 17– 75 eV energy range show an additional resonance near 40 eV. Time-dependent density functional calculations confirm the collective nature of this feature, which is characterized as a dipole-excited volume plasmon made possible by the special fullerene geometry.

Potential Of Multivariate Quantitative Methods For Delineation And Visualization Of Ecoregions, William Hargrove, Forrest Hoffman

United States Department of Energy: Publications

Multivariate clustering based on fine spatial resolution maps of elevation, temperature, precipitation, soil characteristics, and solar inputs has been used at several specified levels of division to produce a spectrum of quantitative ecoregion maps for the conterminous United States. The coarse ecoregion divisions accurately capture intuitively-understood regional environmental differences, whereas the finer divisions highlight local condition gradients, ecotones, and clines. Such statistically generated ecoregions can be produced based on user-selected continuous variables, allowing customized regions to be delineated for any specific problem. By creating an objective ecoregion classification, the ecoregion concept is removed from the limitations of human subjectivity, making …

Carbon Nanotubes With Covalently Linked Porphyrin Antennae: Photoinduced Electron Transfer, Durairaj Baskaran, Jimmy W. Mays, X. Peter Zhang, Matthew S. Bratcher

United States Department of Energy: Publications

Functionalization of carbon nanotubes through surface modification has attracted significant interest recently. Covalent and noncovalent functionalization strategies involving reactions of organic or polymeric molecules onto carbon nanotubes have primarily focused on dispersion or dissolution properties. Incorporation of light absorbing antenna chromophores through a covalent linkage with the extended π electrons of a carbon nanotube would constitute an ideal supramolecular nanoassembly for generating singlet excited energy and its conversion to chemical energy. Porphyrins are one such class of molecules used in assemblies of donor-acceptor materials in molecular electronics and photovoltaic devices.

Several fullerene-based molecular systems with covalently linked porphyrins and metalloporphyrins …

Noncovalent And Nonspecific Molecular Interactions Of Polymers With Multiwalled Carbon Nanotubes, Durairaj Baskaran, Jimmy W. Mays, Matthew S. Bratcher

United States Department of Energy: Publications

Polymer composites containing variable amounts of multiwalled carbon nanotubes (MWNTs) have been prepared using solution dispersion and melt-shear mixing. Various polymer composites with 1 wt % MWNTs have been found to dissolve homogeneously in organic solvents. The amount of polymer coated or wrapped MWNTs dissolved in the solution was quantified using UV-vis absorbance at 500 nm and the concentration ratio of [MWNTs]_solution/[MWNTs]_composite was close to 1. A nonspecific polymer adsorption through multiple-weak molecular interactions of CH groups with MWNTs in the composites has been identified through FTIR spectroscopy. The composites of polybutadiene with different wt % of …

Mole Drainage For Increased Productivity In The South West Irrigation Area, D L. Bennett, Richard George, Bill Russell

Bulletins 4000 -

Heavy soils, with low rates of soil-water movement, such as those found in the South-West Irrigation Area (SWIA), require closely spaced (2-6 m apart) subsoil drainage systems to provide sufficient water movement to control the effects of salt-waterlogging on pastures. Such close spacing using traditional buried pipe or tile drainage systems is impractical. As a result, mole drainage systems, used in other parts of the world for over 50 years, have gained popularity in the SWIA in recent years.

This Bulletin Farmnote reports the current ‘best-bet’ mole draining technique for SWIA conditions gathered from observations over a number of years …

Evaluation Of A Mechanical System For Reconstructing Soil On Surface Mined Land, John P. Fulton, Larry G. Wells

Biosystems and Agricultural Engineering Faculty Publications

The existence of excessive soil compaction has hindered the surface mining industry from returning land to pre−mining productivity after reclamation, especially on prime farmland soils. Heavy earthmoving equipment used during reclamation tends to generate root−limiting bulk densities that adversely affect plant growth thereby decreasing yields. Therefore, the purpose of this study was to evaluate a mechanism, called the ‘Soil Regenerator,’ which reconstructs soil media at minimum bulk density during surface mine reclamation. The prototype soil forming mechanism was mounted on the front of a conventional bulldozer. Soil was placed in long narrow windrows by a scraper or bulldozer. As the …

Optimal Spacings For Two Common Landscape Irrigation Sprinklers, Kody L. Karschnik

The Journal of Undergraduate Research

A simple irrigation system providing sufficient watering needed to make a plant grow is not very difficult. However, to set up a system which provides uniform distribution of water is more difficult. Uniformity coefficients such as Distribution Uniformity and Christiansen coefficient of Uniformity can be used to compare systems and layouts. After measuring the distribution of water from a single sprinkler, a densogram is created with software. The densogram is a numerical and graphical representation of the overlap pattern that the sprinklers create on a given area of surface that is being irrigated. By varying the distance between the sprinklers …

Effects Of Atomic Hydrogen And Deuterium Exposure On High Polarization Gaas Photocathodes, M. Baylac, P. Adderley, J. Brittian, J. Clark, T. Day, J. Grames, J. Hansknecht, M. Poelker, M. Stutzman, A. T. Wu, A. S. Terekhov

United States Department of Energy: Publications

Strained-layer GaAs and strained-superlattice GaAs photocathodes are used at Jefferson Laboratory to create high average current beams of highly spin-polarized electrons. High electron yield, or quantum efficiency (QE), is obtained only when the photocathode surface is atomically clean. For years, exposure to atomic hydrogen or deuterium has been the photocathode cleaning technique employed at Jefferson Laboratory. This work demonstrates that atomic hydrogen cleaning is not necessary when precautions are taken to ensure that clean photocathode material from the vendor is not inadvertently dirtied while samples are prepared for installation inside photoemission guns. Moreover, this work demonstrates that QE and beam …

Radius Of Gyration Of Polystyrene Combs And Centipedes In A Θ Solvent, Ken Terao, Brandon S. Farmer, Yo Nakamura, Hermis Iatrou, Kunlun Hong, Jimmy W. Mays

United States Department of Energy: Publications

The molecular weight dependence of the radii of gyration R_g in a Θ solvent (trans-decalin) of one regular branched comb and three regular centipede polystyrenes was studied using a gel permeation chromatography system equipped with a two-angle light scattering detector and a refractive index detector. R_g in trans-decalin for each sample of particular molecular weight was about 25% smaller than that in a good solvent (tetrahydrofuran, THF). On the other hand, they are 20-40% larger than the theoretical values from the Gaussian chain model. This difference can be explained with the worm-like comb model developed by Nakamura et …

Kinetic Desorption And Sorption Of U(Vi) During Reactive Transport In A Contaminated Hanford Sediment, Nikolla P. Qafoku, John M. Zachara, Chongxuan Liu, Paul Gassman, Odeta Qafoku, Steve Smith

United States Department of Energy: Publications

Column experiments were conducted to investigate U(VI) desorption and sorption kinetics in a sand-textured, U(VI)- contaminated (22.7 µmol kg^-1) capillary fringe sediment from the U.S. Department of Energy (DOE) Hanford site. Saturated column experiments were performed under mildly alkaline conditions representative of the Hanford site where uranyl-carbonate and calcium-uranyl-carbonate complexes dominate aqueous speciation. A U(VI)-free solution was used to study contaminant U(VI) desorption in columns where different flow rates were applied. Sorbed, contaminant U(VI) was partially labile (11.8%), and extended leaching times and water volumes were required for complete desorption of the labile fraction. Uranium- (VI) sorption was …

Cryogenic Laser Induced U(Vi) Fluorescence Studies Of A U(Vi) Substituted Natural Calcite: Implications To U(Vi) Speciation In Contaminated Hanford Sediments, Zheming Wang, John M. Zachara, James Mckinley, Steven Smith

United States Department of Energy: Publications

Time-resolved laser-induced fluorescence spectroscopy (TRLFS) and imaging spectromicroscopy (TRLFISM) were used to examine the chemical speciation of uranyl in contaminated subsurface sediments from the U.S. Department of Energy (U.S. DOE) Hanford Site, Washington. Spectroscopic measurements for contaminant U(VI) were compared to those from a natural, uranyl-bearing calcite (NUC) that had been found via X-ray absorption spectroscopy (XAS) to include uranyl in the same coordination environment as calcium. Spectral deconvolution of TRLFS measurements on the NUC revealed the unexpected presence of two distinct chemical environments consistent with published spectra of U(VI)-substituted synthetic calcite and aragonite. Apparently, some U(VI) substitution sites in …

Impact Of Highly Basic Solutions On Sorption Of Cs+ To Subsurface Sediments From The Hanford Site, Usa, C.C. Ainsworth, John M. Zachara, K. Wagnon, S. Mckinley, Chongxuan Liu, Steven Smith, H.T. Schaef, Paul Gassman

United States Department of Energy: Publications

The effect of caustic NaNO₃ solutions on the sorption of ¹³⁷Cs to a Hanford site micaceous subsurface sediment was investigated as a function of base exposure time (up to 168 d), temperature (10°C or 50°C), and NaOH concentration (0.1 mol/L to 3 mol/L). At 10°C and 0.1 M NaOH, the slow evolution of [Al]_aq was in stark contrast to the rapid increase and subsequent loss of [Al]_aq observed at 50°C (regardless of base concentration). Exposure to 0.1 M NaOH at 10°C for up to 168 d exhibited little if any measurable effect on sediment mineralogy, Cs …

Aeration Strategies And Fan Cost Comparisons For Wheat In Mid-South Production Regions, Thomas C. Bridges, Michael D. Montross, Samuel G. Mcneill

Biosystems and Agricultural Engineering Faculty Publications

Numerous factors influence the sizing of aeration fans for summer-harvested crops. Thirty years of weather data for Lexington, Kentucky, were analyzed and the cost of aeration was compared for two axial fans (afan1, afan2) and one centrifugal fan (cfan1). Aeration costs were defined as the sum of the following components: the cost of owning the fan, the cost of electricity for operating the fan, a cost for wheat shrinkage during aeration, and a cost for dry matter loss (DML). The fans were selected to deliver airflow rates of approximately one, two, and three times the recommended aeration rate of 0.11 …

Streambank Erosion Associated With Grazing Practices In The Humid Region, Carmen T. Agouridis, Dwayne R. Edwards, Stephen R. Workman, José R. Bicudo, Benjamin K. Koostra, Eric S. Vanzant, Joseph L. Taraba

Biosystems and Agricultural Engineering Faculty Publications

The effects of cattle grazing on stream stability have been well documented for the western portion of the U.S., but are lacking for the east. Stream and riparian damage resulting from grazing can include alterations in watershed hydrology, changes to stream morphology, soil compaction and erosion, destruction of vegetation, and water quality impairments. However, few studies have examined the successes of best management practices (BMPs) for mitigating these effects. The objective of this project was to assess the ability of two common BMPs to reduce streambank erosion along a central Kentucky stream. The project site consisted of two replications of …

Evaluation Of Toxic Agent Effects On Lung Cells By Fiber Evanescent Wave Spectroscopy, Pierre Lucas, David Lee Coq, Christophe Juncker, Jayne Collier, Dianne E. Boesewetter, Catherine Boussard-Pledel, Bruno Bureau, Mark R. Riley

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Biochemical changes in living cells are detected using a fiber probe system composed of a single chalcogenide fiber acting as both the sensor and transmission line for infrared optical signals. The signal is collected via evanescent wave absorption along the tapered sensing zone of the fiber. We spectroscopically monitored the effects of the surfactant Triton X-lOO, which serves as a toxic agent simulant on a transformed human lung carcinoma type II epithelial cell line (A549). We observe spectral changes between 2800-3000 cm-1 in four absorptions bands, which are assigned to hydrocarbon vibrations of methylene and methyl groups in membrane lipids. …

Evaluation Of Methods For Estimating Daily Reference Crop Evapotranspiration At A Site In The Humid Southeast United States, R. E. Yoder, Lameck O. Odhiambo, Wesley C. Wright

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Estimated daily reference crop evapotranspiration (ET_o) is normally used to determine the water requirement of crops using the crop factor method. Many ET_o estimation methods have been developed for different types of climatic data, and the accuracy of these methods varies with climatic conditions. In this study, pair−wise comparisons were made between daily ET_o estimated from eight different ET_o equations and ET_o measured by lysimeter to provide information helpful in selecting an appropriate ET_o equation for the Cumberland Plateau located in the humid Southeast United States. Based on the standard error of the …

Remote Estimation Of Canopy Chlorophyll Content In Crops, Anatoly A. Gitelson, Andrés Viña, Veronica Ciganda, Donald Rundquist, Timothy J. Arkebauer

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Accurate estimation of spatially distributed chlorophyll content (Chl) in crops is of great importance for regional and global studies of carbon balance and responses to fertilizer (e.g., nitrogen) application. In this paper a recently developed conceptual model was applied for remotely estimating Chl in maize and soybean canopies. We tuned the spectral regions to be included in the model, according to the optical characteristics of the crops studied, and showed that the developed technique allowed accurate estimation of total Chl in both crops, explaining more than 92% of Chl variation. This new technique shows great potential for remotely tracking the …

Modeling Sediment Trapping In A Vegetative Filter Accounting For Converging Overland Flow, M. J. Helmers, D. E. Eisenhauer, Thomas G. Franti, Michael G. Dosskey

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Vegetative filters (VF) are used to remove sediment and other pollutants from overland flow. When modeling the hydrology of VF, it is often assumed that overland flow is planar, but our research indicates that it can be two-dimensional with converging and diverging pathways. Our hypothesis is that flow convergence will negatively influence the sediment trapping capability of VF. The objectives were to develop a two-dimensional modeling approach for estimating sediment trapping in VF and to investigate the impact of converging overland flow on sediment trapping by VF. In this study, the performance of a VF that has field-scale flow path …

Beneficial Reuse And Sustainability: The Fate Of Organic Compounds In The Land-Applied Waste, M. R. Overcash, Ronald C. Sims, J. L. Sims, K. C. Nieman

Biological Engineering Faculty Publications

Land application systems, also referred to as beneficial reuse systems, are engineered systems that have defined and permitted application areas based on site and waste characteristics to determine the land area size requirement. These terrestrial systems have orders of magnitude greater microbial capability and residence time to achieve decomposition and assimilation compared with aquatic systems. In this paper we focus on current information and information needs related to terrestrial fate pathways in land treatment systems. Attention is given to conventional organic chemicals as well as new estrogenic and pharmaceutical chemicals of commerce. Specific terrestrial fate pathways addressed include: decomposition, bound …

California Energy Commission Agricultural Peak Load Reduction Program Case Study: Orange Cove Id, Charles M. Burt, Daniel J. Howes

BioResource and Agricultural Engineering

The Orange Cove Irrigation District is located in Fresno and Tulare Counties, approximately 30 miles southeast of Fresno and 20 miles north of the City of Visalia. The Friant-Kern Canal is the district’s main source of water to supply 28,000 acres of farmland.

California Energy Commission Agricultural Peak Load Reduction Program Case Study: Berrenda Mesa Wsd, Charles M. Burt, Daniel J. Howes

BioResource and Agricultural Engineering

Berrenda Mesa Water Storage District (BMWSD) is located in the southern part of the San Joaquin Valley near Bakersfield. The district receives water from the State Water Project – California Aqueduct.