Bioresource and Agricultural Engineering Commons^™

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.

Evaluation Of Niobium As Candidate Electrode Material For Dc High Voltage Photoelectron Guns, M. Bastaninejad, Md. Abdullah Mohamed, A. A. Elmustafa, P. Adderley, J. Clark, S. Covert, J. Hansknecht, C. Hernandez-Garcia, M. Poelker, R. Mammei, K. Surles-Law, P. Williams

United States Department of Energy: Publications

The field emission characteristics of niobium electrodes were compared to those of stainless steel electrodes using a DC high voltage field emission test apparatus. A total of eight electrodes were evaluated: two 304 stainless steel electrodes polished to mirror like finish with diamond grit and six niobium electrodes (two single-crystal, two large-grain, and two fine-grain) that were chemically polished using a buffered-chemical acid solution. Upon the first application of high voltage, the best large-grain and single-crystal niobium electrodes performed better than the best stainless steel electrodes, exhibiting less field emission at comparable voltage and field strength. In all cases, field …

Saturated–Unsaturated Flow In A Compressible Leaky-Unconfined Aquifer, Phoolendra Mishra, Velimir Vesselinov, Kristopher Kuhlman

United States Department of Energy: Publications

An analytical solution is developed for three-dimensional flow towards a partially penetrating largediameter well in an unconfined aquifer bounded below by a leaky aquitard of finite or semi-infinite extent. The analytical solution is derived using Laplace and Hankel transforms, then inverted numerically. Existing solutions for flow in leaky unconfined aquifers neglect the unsaturated zone following an assumption of instantaneous drainage due to Neuman. We extend the theory of leakage in unconfined aquifers by (1) including water flow and storage in the unsaturated zone above the water table, and (2) allowing the finite-diameter pumping well to partially penetrate the aquifer. The …

P96. Three-Dimensional Morphometry Of Human Cervical Endplates, Rebecca A. Wachs, Victoria M. Michna, Eric H. Ledet

Department of Agricultural and Biological Systems Engineering: Faculty Publications

BACKGROUND CONTEXT: Degeneration of the cervical intervertebral disc is the underlying cause for many patients suffering from neck and upper extremity pain. Anterior cervical discectomy and fusion, and cervical disc replacements are common, but next generation implants and less invasive surgical techniques are predicated on a comprehensive characterization of cervical endplate morphology. To date, cervical endplate morphometry has not been described in detail, and age-related and gender- dependent differences have not been characterized.

PURPOSE: The purposes of this research were to measure cervical endplate morphometry in both men and women across three decades of life and characterize age, gender, and …

Field Performance Evaluation Of A Ventilation System: A Swine Case Study, Jay D. Harmon, Michael C. Brumm, Larry D. Jacobson, Stephen H. Pohl, David R. Stender, Richard R. Stowell

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Swine finishing facility ventilation has become relatively complex and is often mismanaged as a system. One of the few ways to truly understand these systems is to spend time systematically going through the many components of the building and how they work as a system. To learn to help producers better, a team of university Extension specialists that included agricultural engineers and animal scientists spent an extended period carefully documenting conditions in a deep‐pit swine finishing building with two 1,000‐head rooms. Exhaust fans connected to the manure pit and wall fans were operated at various stages as a negative‐pressure ventilation …

Microstructural And Mineralogical Transformation Of Hydraulically Disposed Fly Ash—Implications To The Environment, Jabulani S. Mahlaba, Elsabe P. Kearsley, Richard A. Kruger

Coal Combustion and Gasification Products Journal Archive

Increasing amounts of coal are combusted annually to meet the ever-increasing energy demands. The inevitable by-products include fly ash and saline effluents, which require acceptable disposal. The aim of this article is to compare the effect of hydraulic disposal with dry ash dumping. The results indicate that the former carries more environmental benefits based on the physical, chemical, and mineralogical aspects that were investigated.

Cordyline Fruticosa Growth And Soil Microbial Quality With Topical Application Of Coal Combustion By-Products Aggregates, Sangchul Hwang, Isomar Latorre, Eileen Irizarry

Coal Combustion and Gasification Products Journal Archive

Coal combustion by-products aggregates (CCAs) are a solidified composite of fly and bottom ashes (2:1, by wt). Here, we assessed the feasibility of beneficial use of CCAs as a soil amendment or conditioner by conducting an outdoor experiment with Cordyline fruticosa (lucky plant) to determine its growth and soil microbial quality under the influence of topical CCA application (95 tons ha21). Enhanced growth of C. fruticosa with CCA application was noted, with respect to plant height, growth rate, leaf size, and leaf chlorophyll intensity. Soil dehydrogenase activity and total heterotrophic bacteria count were greater with topical CCA application, especially in …

Influence Of Activator Solution Formulation On Fresh And Hardened Properties Of Low-Calcium Fly Ash Geopolymer Concrete, Carlos Montes, Erez N. Allouche

Coal Combustion and Gasification Products Journal Archive

The effect of the composition of activator solutions on fresh and hardened properties of geopolymer concrete was investigated. Research variables included liquid sodium silicate product (DH, NH, and StarH), sodium hydroxide molar concentration (6, 10, and 14), and sodium silicate–to–sodium hydroxide ratio (1, 2, and 3). Response variables were compressive strength, corrosion resistance expressed as remaining compressive strength and mass loss, and flowability. Results were analyzed using Minitab statistical software. Findings suggest that activator solution formulation has a significant effect on the properties of the resulting geopolymer binder. The experimental design used was found effective in establishing the optimum activator …

Mineralogical Transformations In Coal Feedstocks During Carbon Conversion, Based On Packed-Bed Combustor Tests: Part 2. Behavior Of Individual Particles, Ratale H. Matjie, Colin R. Ward, Zhongsheng Li

Coal Combustion and Gasification Products Journal Archive

Handpicked carbon-rich particles (coal or char), mineral-rich particles (heated stones), and bonded stone aggregates (clinkers) from the upper and lower parts of a pilot-scale packed-bed combustor bed, designed to simulate conversion or combustion processes, were subjected to mineralogical and inorganic geochemical studies, in order to evaluate the reactions that may occur during carbon conversion at a particle-by-particle scale. The mineral matter of the carbon-rich particles was found to have higher proportions of carbonate minerals and kaolinite than the mineral-rich (stone) particles in the coal feedstocks used in the study, and to form phases such as anorthite, gehlenite, pyrrhotite, troilite, and …

Mineralogical Transformations In Coal Feedstocks During Carbon Conversion, Based On Packed-Bed Combustor Tests: Part 1. Bulk Coal And Ash Studies, Ratale H. Matjie, Colin R. Ward, Zhongsheng Li

Coal Combustion and Gasification Products Journal Archive

Mineralogical and inorganic geochemical studies have been carried out on composite samples of six different coarse-crushed (,120 mm) feed coals tested in a pilot-scale packed-bed combustor designed to simulate conversion and some fixed-bed combustion processes, and also on composite samples of the ashes produced. The mineral matter of the coals consisted mainly of quartz, kaolinite, and Ca-bearing carbonate minerals (calcite, dolomite, aragonite), with minor proportions of illite, pyrite, and several other phases, along with some Ca in an organically associated form. The base to acid ratio of the coal ashes ranged from 0.1 to 0.3, due mainly to variations in …

Potential Indoor Air Exposures And Health Risks From Mercury Off-Gassing Of Coal Combustion Products Used In Building Materials, Christopher M. Long, Sonja N. Sax, Ari S. Lewis

Coal Combustion and Gasification Products Journal Archive

Coal combustion products (CCPs), including coal fly ash (CFA) and flue gas desulfurization (FGD) gypsum, have gained accepted use as substitutes for traditional substances in building materials. Because of the presence of mercury (Hg) in CCP materials, some concerns have been raised regarding the potential for Hg to off-gas from building materials into indoor air. Risk assessment offers a well-accepted, objective framework in which to determine whether such off-gassing could result in humanexposures of health concern. We thus conducted a screening-level human health risk assessment to estimate worst-case inhalation risks from indoor air exposures to Hg for multiple CCP utilization …

Quantifying The Benefits Of Using Flue Gas Desulfurization Gypsum In Sustainable Wallboard Production, Jin Cheol Lee, Sabrina L. Bradshaw, Tuncer B. Edil, Craig H. Benson

Coal Combustion and Gasification Products Journal Archive

Electric utilities produce more than 11.2 Mt of flue gas desulfurization (FGD) gypsum annually. Approximately 7.5 Mt is used in wallboard production. This article examines the environmental and cost benefits associated with replacement of natural gypsum in wallboard with FGD gypsum. A life-cycle analysis program was used to quantify the benefits of using FGD gypsum from electric power production in wallboard construction. Comparisons were made between energy consumption, water use, and greenhouse gas (GHG) emissions associated with obtaining and processing virgin gypsum material and those with FGD gypsum. The added impact of disposing of the unused FGD gypsum in landfills …

Waste Classification Of Slag Generated In A Pilot-Scale Entrained-Flow Gasifier, Ashleigh Cousins, Robin W. Hughes, David J. Mccalden, Dennis Y. Lu, Edward J. Anthony

Coal Combustion and Gasification Products Journal Archive

Series of gasification tests have been completed in the pilot-scale entrained-flow slagging gasifier at CanmetENERGY using Canadian coals, oil-sand coke, and blends of these fuels to determine if the produced slags are nonhazardous in nature. Solid wastes generated during these tests were analyzed for their trace metals, crystallinity, and toxic constituent leaching tendency in an attempt to provide more insight into the possibility of disposal or by-product use of gasifier-produced solid waste. The gasification tests were performed at conditions representative of commercial gasifiers using a dry-fuel-feed configuration. The lower-volatility elements were found to partition between the slag and process-water solids …

Trapping Phosphorus In Runoff With A Phosphorus Removal Structure, Chad J. Penn, Joshua M. Mcgrath, Elliott Rounds, Garey A. Fox, Derek M. Heeren

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Reduction of phosphorus (P) inputs to surface waters may decrease eutrophication. Some researchers have proposed fi ltering dissolved P in runoff with P-sorptive byproducts in structures placed in hydrologically active areas with high soil P concentrations. Th e objectives of this study were to construct and monitor a P removal structure in a suburban watershed and test the ability of empirically developed fl ow-through equations to predict structure performance. Steel slag was used as the P sorption material in the P removal structure. Water samples were collected before and after the structure using automatic samples and analyzed for total dissolved …

A Submersible Magnetic Stirrer For Use In Measuring Photosynthesis In A Biofloc Technology Production System, Bartholomew W. Green, E. Gregory O'Neal

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Measuring photosynthesis or primary productivity in biofloc technology production systems is challenging because the biofloc must be maintained in suspension constantly. Photosynthesis can be measured in external incubators designed to keep the biofloc suspended in the biochemical oxygen demand (BOD) bottle, but primary productivity must be measured in the biofloc technology production system culture unit. Therefore, a submersible device is required to keep the biofloc suspended in the BOD bottle. This report details a submersible, air-powered magnetic stirrer that we designed, fabricated from off-the-shelf materials, and tested in biofloc technology production system tanks.

2012 Nebraska Water Monitoring Programs Report, Marty Link, Mike Archer

Nebraska Department of Environmental Quality: Reports

The following Nebraska Department of Environmental Quality staff have contributed to this report with their photos, maps, numbers, words, and editing. Their efforts are greatly appreciated and gratefully acknowledged here: Mike Archer, Ken Bazata, Dave Bubb, Ryan Chapman, Jason Garber, Patrick Hartman, Tom Heatherly, Dave Ihrie, Dan Inman, Greg Michl, Will Myers, Patrick O’Brien (NARD), Brad Routt, and Dave Schumacher.

Sparse Pseudospectral Approximation Method, Paul G. Constantine, Michael Eldred, Eric Phipps

United States Department of Energy: Publications

Multivariate global polynomial approximations – such as polynomial chaos or stochastic collocation methods – are now in widespread use for sensitivity analysis and uncertainty quantification. The pseudospectral variety of these methods uses a numerical integration rule to approximate the Fourier-type coefficients of a truncated expansion in orthogonal polynomials. For problems in more than two or three dimensions, a sparse grid numerical integration rule offers accuracy with a smaller node set compared to tensor product approximation. However, when using a sparse rule to approximately integrate these coefficients, one often finds unacceptable errors in the coefficients associated with higher degree polynomials.

By …

Raman/Rayleigh Scattering And Co-Lif Measurements In Laminar And Turbulent Jet Flames Of Dimethyl Ether, Frederik Fuest, Robert S. Barlow, Jyh-Yuan Chen, Andreas Dreizler

United States Department of Energy: Publications

To reduce the impact of combustion of fossil fuels on air quality and climate change, dimethyl ether (DME) is a promising alternative diesel fuel candidate. Technical combustion processes, including formation of pollutants, are influenced by turbulence–chemistry interaction. Therefore, accurate prediction by computational combustion models of combustion systems burning DME must account for multiple scalars and scalar gradients. The testing of such models requires detailed experiments. Here a study is presented on the feasibility of simultaneous species and temperature measurements in turbulent dimethyl ether flames, using line-imaged Raman/Rayleigh scattering of the major species H₂, O₂, N_{2 …}

Application Of Pdf Mixing Models To Premixed Flames With Differential Diffusion, Edward Richardson, Jacqueline Chen

United States Department of Energy: Publications

Differential diffusion alters the balance of reaction and diffusion in turbulent premixed combustion, affecting the performance and emissions of combustion devices. Modelling combustion devices with Probability or Filtered Density Function (PDF or FDF) methods provides an exact treatment for the change in composition due to chemical reaction, while molecular mixing has to be modelled. Previous PDF molecular mixing models do not account for differential diffusion in a manner which satisfies realizability requirements. A new approach for treating differential diffusion, which ensures realizability, is proposed for pairwise-exchange mixing models in general, and applied in the Interaction by Exchange with the Mean …

Pore-Scale Characterization Of Biogeochemical Controls On Iron And Uranium Speciation Under Flow Conditions, Carolyn I. Pearce, Michael J. Wilkins, Changyong Zhang, Steve M. Heald, James K. Fredrickson, John M. Zachara

United States Department of Energy: Publications

Etched silicon microfluidic pore network models (micromodels) with controlled chemical and redox gradients, mineralogy, and microbiology under continuous flow conditions are used for the incremental development of complex microenvironments that simulate subsurface conditions. We demonstrate the colonization of micromodel pore spaces by an anaerobic Fe(III)-reducing bacterial species (Geobacter sulfurreducens) and the enzymatic reduction of a bioavailable Fe(III) phase within this environment. Using both Xray microprobe and X-ray absorption spectroscopy, we investigate the combined effects of the precipitated Fe(III) phases and the microbial population on uranium biogeochemistry under flow conditions. Precipitated Fe(III) phases within the micromodel were most effectively …