Bioresource and Agricultural Engineering Commons^™

Valence-Shell Photoionization Of The Chlorinelike Ca3+ Ion, Ghassan A. Alna’Washi, M. Lu, M. Habibi, R. A. Phaneuf, A. L. D. Kilcoyne, A. S. Schlachter, C. Cisneros, B. M. Mclaughlin

United States Department of Energy: Publications

Absolute photoionization measurements were performed for a mixture of ²P^o_3/2 ground-state and ²P^o_1/2 metastable-state Ca³⁺ ions over the photon energy range 65.7–104.6 eV by merging an ion beam with a beam of monochromatized synchrotron radiation. The ionization threshold energy of the ²P^o_3/2 ground state was measured to be 67.063 ± 0.015 eV, which is 0.207 eV lower than the value tabulated in the NIST database. Most of the observed resonances associated with multiple Rydberg series of autoionizing states have been assigned spectroscopically using the quantum defect form of the Rydberg …

Nebraska Agricultural Water Management Demonstration Network (Nawmdn): Integrating Research And Extension/Outreach, Suat Irmak, Jennifer M. Rees, Gary L. Zoubek, Brandy S. Van Dewalle, William R. Rathje, Rodney Debuhr, Dan Leininger, Darrel D. Siekman, James W. Schneider, Andrew P. Christiansen

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Maximizing the net benefits of irrigated plant production through appropriately designed agricultural water management programs is of growing importance in Nebraska, and other western and Midwestern states, because many areas are involved in management and policy changes to conserve irrigation water. In Nebraska, farmers are being challenged to practice conservation methods and use water resources more efficiently while meeting plant water requirements and maintaining high yields. Another challenge Nebraska experiences in it's approximately 3.5‐million‐ha irrigated lands is limited adoption of newer technologies/tools to help farmers better manage irrigation, conserve water and energy, and increase plant water use efficiency. In 2005, …

Effect Of Magnetron Frequency On Heating Pattern In Domestic Oven, Sohan Birla, Krishnamoorthy Pitchai, Jeyamkondan Subbiah, David D. Jones

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

In this study a computer model was developed to simulate microwave heating of a model food with a range of magnetron frequencies. The range was decided upon performing the frequency spectrum analysis of microwave leakage from the microwave oven. Simulation results showed that the magnetron input as sinusoidal frequency from 2.44 GHz to 2.48 GHz generates different heating profiles. The simulated heating profiles were compared with experimental heating profiles obtained by using an IR camera. None of simulations with individual frequency exactly matches with experimental temperature profile. The closet match between simulated and observed temperature profiles was found with 2.46 …

Extrusion Systems: Components, Qi Fang, Milford Hanna

Department of Agricultural and Biological Systems Engineering: Faculty Publications

An extrusion system can be very simple to very complex. The complexity, or versatility, of a particular system is determined by the range of feedstocks to be processed, the desired transformations of the feedstocks, and the desired form of the products resulting from the process. These determine the specific design requirements of the various components of an extrusion system.

Opto-Electrophoretic Detection Of Bio-Molecules Using Conducting Chalcogenide Glass Sensors, Zhiyong Yang, Megan K. Fah, Kelly A. Reynolds, Jonathan D. Sexton, Mark R. Riley, Marie-Laure Anne, Bruno Bureau, Pierre Lucas

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Novel telluride glasses with high electrical conductivity, wide infrared transparency and good resistance to crystallization are used to design an opto-electrophoretic sensor for detection and identification of hazardous microorganisms. The sensor is based on an attenuated total reflectance element made of Ge-As-Te glass that serves as both an optical sensing zone and an electrode for driving the migration of bio-molecules within the evanescent wave of the sensor. An electric field is applied between the optical element and a counter electrode in order to induce the migration of bio-molecules carrying surface charges. The effect of concentration and applied voltage is tested …

On The Dynamics Of Canopy Resistance: Generalized Linear Estimation And Relationships With Primary Micrometeorological Variables, Suat Irmak, Denis Mutiibwa

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The 1‐D and single layer combination‐based energy balance Penman‐Monteith (PM) model has limitations in practical application due to the lack of canopy resistance (r_c) data for different vegetation surfaces. r_c could be estimated by inversion of the PM model if the actual evapotranspiration (E_Ta) rate is known, but this approach has its own set of issues. Instead, an empirical method of estimating r_c is suggested in this study. We investigated the relationships between primary micrometeorological parameters and rc and developed seven models to estimate r_c for a nonstressed maize canopy on an hourly …

Nebraska Water And Energy Flux Measurement, Modeling, And Research Network (Nebflux), Suat Irmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Surface energy and water vapor fluxes play a critical role in understanding the response of agro‐ecosystems to changes in environmental and atmospheric parameters. These fluxes play a crucial role in exploring the dynamics of water and energy use efficiencies of these systems. Quantification of the fluxes is also necessary for assessing the impact of land use and management changes on water balances. Accomplishing these goals requires measurement of water vapor and energy exchanges between various vegetation surfaces and microclimates for long‐enough periods to understand the behavior and dynamics involved with the flux transfer so that robust models can be developed …

Low-Cost Obstacle Detection Sensor Array For Unmanned Agricultural Vehicles, Santosh Pitla, Joe D. Luck, Scott A. Shearer

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

Mobile robots deployed for agricultural applications must operate in harsh environments where they encounter a variety of both moveable and immovable obstacles. Typically, robots utilize vision sensors to learn about the environment in which they are working. In this study, a low-cost infra-red (IR) sensor array was developed to act as an obstacle detection aid for an unmanned agricultural vehicle (UAgV). The IR sensor array developed consists of six IR sensors mounted on two orthogonal steel plates. The array of sensors was continuously oscillated about the yaw-axis to traverse a 200° field of view in front of the UAgV. Three …

2010 Nebraska Water Monitoring Programs Report, Marty Link

Nebraska Department of Environmental Quality: Reports

The Nebraska Department of Environmental Quality (NDEQ) is charged with monitoring, assessing, and to the extent possible, managing the state’s water resources. The purpose of this work is to protect and maintain good quality water and encourage or execute activities to improve poor water quality. Monitoring is done on the over 18,000 miles of flowing rivers and streams, our greater than 280,000 acres of surface water in lakes and reservoirs, and the vast storage of groundwater in Nebraska’s aquifers.

Validation Of A Model For Static And Dynamic Recrystallization In Metals, Arthur Brown, Douglas Bammann

United States Department of Energy: Publications

In this paper, modifications are proposed to a phenomenological plasticity model to account for the evolution of recrystallization and the resultant softening behavior. The novel model includes internal state variables representing dislocation density and the spacing between geometrically necessary subgrain boundaries. In order to capture both single and multiple peak recrystallization, the model tracks the evolution of recrystallized volume fractions for multiple cycles of recrystallization, and has a set of state variables for each volume fraction. A rule of mixtures is used to determine the average stress. The model is capable of capturing static recrystallization as well as both single …

Fractionation Of Oxygen Isotopes In Phosphate During Its Interactions With Iron Oxides, Deb P. Jaisi, Ruth E. Blake, Ravi K. Kukkadapu

United States Department of Energy: Publications

Iron (III) oxides are ubiquitous in near-surface soils and sediments and interact strongly with dissolved phosphates via sorption, co-precipitation, mineral transformation and redox-cycling reactions. Iron oxide phases are thus, an important reservoir for dissolved phosphate, and phosphate bound to iron oxides may reflect dissolved phosphate sources as well as carry a history of the biogeochemical cycling of phosphorus (P). It has recently been demonstrated that dissolved inorganic phosphate (DIP) in rivers, lakes, estuaries and the open ocean can be used to distinguish different P sources and biological reaction pathways in the ratio of ¹⁸O/¹⁶O (δ¹⁸O …

Role Of Outer-Membrane Cytochromes Mtrc And Omca In The Biomineralization Of Ferrihydrite By Shewanella Oneidensis Mr-1, C. L. Reardon, Alice Dohnalkova, P. Nachimuthu, David Kennedy, D. A. Saffarini, B. W. Arey, L. Shi, Zheming Wang, D. Moore, J. S. Mclean, D. Moyles, M. J. Marshall, John M. Zachara, James K. Fredrickson, A. S. Beliaev

United States Department of Energy: Publications

In an effort to improve the understanding of electron transfer mechanisms at the microbe–mineral interface, Shewanella oneidensis MR-1 mutants with in-frame deletions of outer-membrane cytochromes (OMCs), MtrC and OmcA, were characterized for the ability to reduce ferrihydrite (FH) using a suite of microscopic, spectroscopic, and biochemical techniques. Analysis of purified recombinant proteins demonstrated that both cytochromes undergo rapid electron exchange with FH in vitro with MtrC displaying faster transfer rates than OmcA. Immunomicroscopy with cytochrome-specific antibodies revealed that MtrC co-localizes with iron solids on the cell surface while OmcA exhibits a more diffuse distribution over the cell surface. After 3-day …

Testing Fuel Efficiency Of Tractors With Both Continuously Variable And Standard Geared Transmissions, Christopher N. Howard

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

A John Deere 8295R IVT tractor with a continuously variable transmission (CVT) and a John Deere 8295R PowerShift (PST) tractor (Waterloo, Iowa) with a standard geared transmission (GT) were tested for fuel consumption at three different travel speeds with six different load levels applied per speed. The JD 8295R PST tractor was tested both at full throttle (FT) and shifted up two gears and throttled back (SUTB) to achieve the same travel speed as at full throttle conditions. The three speeds tested corresponded to the maximum speeds achieved in 6th, 8th and 10th gear for the JD 8295R PST tractor …

Heating Performance Assessment Of Domestic Microwave Ovens, Krishnamoorthy Pitchai, Sohan Birla, Jeyamkondan Subbiah, David D. Jones

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

Due to inherent nature of standing wave patterns of microwaves inside a cavity and dielectric properties of different components in a food, microwave heating leaves non-uniform distribution of energy inside the food volumetrically. Achieving heating uniformity plays critical role in improving the safety of microwave heated products. In this paper, we present a method for assessing heating uniformity within domestic microwave ovens. A custom designed container
was used to assess heating uniformity of a range of microwave ovens using IR camera. The study suggested that the best place to place food in a microwave oven is not at center but …

Generating ‘As-Applied’ Pesticide Distribution Maps From A Self-Propelled Agricultural Sprayer Based On Nozzle Pressure Data, Joe D. Luck, Ajay Sharda, Santosh Pitla, John P. Fulton, Scott A. Shearer

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

The application of pre-emergence, post-emergence, and burn-down herbicides (i.e., glyphosate) continues to increase as producers attempt to reduce both negative environmental impacts from tillage and input costs from labor, machinery and materials. The use of precision agriculture technologies such as automatic boom section control allows producers to reduce offtarget application when applying herbicides. While automatic boom section control provides benefits, pressure differences across the spray boom resulting from boom section actuation can lead to offrate application errors. Off-rate errors may also result from spray rate controller compensation for ground speed changes and velocity variation across the spray boom during turning …

Numerically Predicting Seepage Gradient Forces And Erosion: Sensitivity To Soil Hydraulic Properties, Garey A. Fox, Derek M. Heeren, Glenn V. Wilson, E. J. Langendoen, Amanda K. Fox, Maria L. Chu-Agor

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Research has suggested that streambank seepage can be an important mechanism of bank instability; however, limited information is available on the level of soil characterization necessary to accurately predict seepage gradient forces and erosion. The objective of this research was to quantify the expected range of predicted seepage gradients for various degrees of site characterization. Uncertainty analysis on seepage gradient predictions was performed relative to variability in soil hydraulic properties. A two-dimensional unsaturated/saturated groundwater flow model was used to simulate a homogeneous soil layer for sand and loamy sand soils packed at various bulk densities, ρ_b. A pedotransfer …

Nebraska Agricultural Water Management Demonstration Network (Nawmdn): Integrating Research And Extension/Outreach, Suat Irmak, Jennifer M. Rees, Gary L. Zoubek, Brandy S. Van Dewalle, William R. Rathje, Rodney Debuhr, Dan Leininger, Darrel D. Siekman, James W. Schneider, Andrew P. Christiansen

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Maximizing the net benefits of irrigated plant production through appropriately designed agricultural water management programs is of growing importance in Nebraska, and other western and Midwestern states, because many areas are involved in management and policy changes to conserve irrigation water. In Nebraska, farmers are being challenged to practice conservation methods and use water resources more efficiently while meeting plant water requirements and maintaining high yields. Another challenge Nebraska experiences in it's approximately 3.5‐million‐ha irrigated lands is limited adoption of newer technologies/tools to help farmers better manage irrigation, conserve water and energy, and increase plant water use efficiency. In 2005, …

161. The Potential Role Of Extensor Muscle Fatigue In The Onset Of Intervertebral Disc Degeneration: A Novel In Vivo Model, Mary Beth M. Grabowsky, Nicholas A. Pallota, Matthew W. Connelly, Brett Van Etten, Rebecca A. Wachs, Max Alley, Joseph C. Glennon, Andrew H. Dubin, John W. German, Richard L. Uhl, Eric H. Ledet

Department of Agricultural and Biological Systems Engineering: Faculty Publications

BACKGROUND CONTEXT: Occupation is strongly correlated to low back pain (LBP). Specific occupational activities associated with low back pain include poor posture, whole body vibration, and repetitive lifting. These activities have a common link: they result in fatigue of the primary spinal extensor musculature. This fatigue may lead to increased intervertebral loading - a stimulus for disc degeneration. If true, this association could provide a vital connection between detrimental physical activities and LBP. However, the link between muscle fatigue and increased load across the disc space has never been quantified in vivo.

PURPOSE: The purpose of this study was to …

Next Generation Biofuels And Advanced Engines For Tomorrow’S Transportation Needs, Sandia National Laboratories, Doe Combustion Research Facility, Doe Joint Bioenergy Institute

United States Department of Energy: Publications

In November 2009, Sandia National Laboratories hosted the Next Generation Biofuels and Advanced Engines for Tomorrow’s Transportation Needs Workshop. The event focused on the combined opportunities in biofuels and engines in the transportation sector. The workshop brought together the DOE Combustion Research Facility and the DOE Joint BioEnergy Institute along with oil companies, biofuel developers, engine manufacturers, suppliers, and experts from the university, regulatory, finance, and national laboratory communities. The intersection of biofuels and engines, if properly scaled, can meet a triad of national goals:

• Reduced climate impact

• Economic development

• Energy security through energy diversity

The workshop …

Nutrient And Bacterial Transport In Runoff From Soil And Pond Ash Amended Feedlot Surfaces, John E. Gilley, Jason R. Vogel, Elaine D. Berry, Roger Eigenberg, David B. Marx, Brian L. Woodbury

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The addition of pond ash (fly ash that has been placed in evaporative ponds and subsequently dewatered) to feedlot surfaces provides a healthier environment for livestock and economic advantages for the feedlot operator. However, the water quality effects of pond ash amended surfaces are not well understood. The objectives of this field investigation were to: (1) compare feedlot soil properties, and nutrient and bacterial transport in runoff, from pond ash amended surfaces and soil surfaces; (2) compare the effects of unconsolidated surface materials (USM) (loose manure pack) and consolidated subsurface materials (CSM) (compacted manure and underlying layers) on nutrient and …

Evaluation Of A Terrain Attribute Model For Locating Areas Suitable For Grassed Waterways In Agricultural Settings, Joe D. Luck, Adam C. Pike, Santosh Pitla, Tom Mueller, Scott A. Shearer

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

Grassed waterways placed in high water flow zones substantially reduce erosion in agricultural fields. A recent study proposed a statistical model for waterway planning for a farm in the Outer Bluegrass physiographic region of Kentucky. The logistic regression model identified where channel erosion was likely to occur based on elevation-derived terrain attributes. The objective of this study was to test their model in fields located in the Western Coal Fields physiographic region where soils differ substantially. Model predictions corresponded well with known areas of concentrated flow (i.e., maps of existing waterways, surface drains, and observations of erosion). The geographic inference …

Guidance Directrix Generation Using Laser Sensors, Santosh Pitla, Joe D. Luck, Scott A. Shearer

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

A sensor array consisting of two laser sensors was utilized to determine the guidance directrix (offset distance-d, heading angle-ø) that are required as reference inputs for an automated guidance system. The sensor array was evaluated in both laboratory and field conditions. Under laboratory conditions the sensor array replicated the physical profile of the target surface with a 4% error in determining the heading angle. Field tests were conducted in two types of crops; corn and alfalfa. The sensor array identified the cut-crop edge profile ahead of the tractor and replicated distinct shapes of the cut-crop edge. RMSE values in determining …

Preferential Flow Path Effects On Subsurface Contaminant Transport In Alluvial Floodplains, Derek M. Heeren, Ronald B. Miller, Gary A. Fox, Daniel E. Storm, Chad J. Penn, Todd Halihan

Department of Agricultural and Biological Systems Engineering: Faculty Publications

For strongly sorbing contaminants, transport from upland areas to surface water systems is typically considered to be due to surface runoff with subsurface transport assumed negligible. However, certain local conditions can lead to an environment where subsurface transport to streams may be significant, a source of contamination not alleviated by current best management practices (e.g. riparian buffers). The Ozark region, including parts of Oklahoma, Arkansas, and Missouri, is characterized by cherty, gravelly soils and gravel bed streams. Previous research identified a preferential flow path (PFP) at a field site along the Barren Fork Creek in northeastern Oklahoma. With the subsoils …

Development Of Gis-Based Chemical Distribution Maps From Sprayer Performance Data, Joe D. Luck, Santosh Pitla, Rodrigo S. Zandonadi, Scott A. Shearer

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

Pesticide application is an essential practice on farms in Kentucky where glyphosate resistant crops and no-till farming strategies are becoming more popular. Off-rate pesticide application errors are the result of incorrect concentrations applied to an area of the field and may result from velocity changes along the spray boom while the sprayer is turning, pressure changes across the width of the spray boom, and changes in effective boom height due to undulating terrain. In an attempt to estimate potential errors resulting from sprayer turning movements, a method was developed to compare the differences in application areas between control sections across …

Cut Crop Edge Detection Using A Laser Sensor, Santosh Pitla, Joe D. Luck, Scott A. Shearer

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

An off-the-shelf low cost laser sensor was tested and evaluated both in laboratory and field conditions. The sensor identified the angular and straight edges of the laboratory test surface and replicated the straight edge profile with an error of 4%. In field conditions, the sensor identified three types of cut crop edges (wheat, alfalfa and corn) and replicated distinct shapes (triangle, curved and rectangular edges). The sensor was tested at two sensor path offset distances and three tractor/sensor speeds (3.2, 6.4 and 9.6 km/h). In all test runs the sensor detected the cut-crop edges. Standard deviations and RMSE values in …

Adsorption And Desorption Of Phosphorus And Nitrogen By Immersed Stalks, John E. Gilley, Bahman Eghball, David B. Marx

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Adsorption and desorption of phosphorus (P) and nitrogen (N) by stalk residues may influence the concentrations of P and N in runoff. A laboratory study was conducted to measure the effects of P and N constituents in solution on adsorption and desorption of P and N by corn, soybean, and wheat stalk residues. Experimental variables included type of stalk material (corn, soybean, and wheat), inorganic nutrients in solution (PO₄-P and NO₃-N; PO₄-P and NH₄-N; NO₃-N and NH₄-N; and PO₄-P, NO₃-N, and NH₄-N), …

Perspectives On Energy Policy: Security, Economics, And The Environment, Sandia National Laboratories

United States Department of Energy: Publications

On March 18 and 19, 2009, Sandia National Labo­ratories and the University of California San Diego (UCSD) Sustainability Solutions Institute (SSI) brought together 27 leaders from academia, govern­ment, and the private sector to discuss key energy policy issues and proposed values- and outcomes-based approaches to energy policy. The goal of the workshop was to bring together leaders from diverse backgrounds to identify promising areas for energy policy, based on the understanding of intersecting issues, assumptions, and priorities from the national security, economic, and environmental perspectives.

Participants:  Charles Kennel, University of California, San Diego; Les Shephard, Sandia National Laboratories; Michael Aimone, …

90-Billion Gallon Biofuel Deployment Study -- Executive Summary, Sandia National Laboratories

United States Department of Energy: Publications

This study concludes that 90 billion gallons per year of biomass-derived ethanol can be produced and distributed with enduring government commitment and continued technological progress. Specifically, the model projects that 90 billion gallons of ethanol can be produced per year in the U.S.: 15 billion gallons per year from corn ethanol, with the balance from cellulosic ethanol.

Recovery Of Biodiesel Precursors From Heterotrophic Microalga Chlorella Protothecoides, Peter B. Merkle

United States Department of Energy: Publications

This working paper describes an experimental program to assess the suitability of largescale separation processing of algal biomass in aqueous culture. It assumes the possibility of successful large-scale growth of heterotrophic Chlorella protothecoides to produce algal lipid/free fatty acid (FFA) biodiesel precursors.

Surface-Initiated Titanium-Mediated Coordination Polymerization From Catalyst-Functionalized Single And Multiwalled Carbon Nanotubes, Dimitrios Priftis, Nikolaos Petzetakis, Georgios Sakellariou, Marinos Pitsikalis, Durairaj Baskaran, Jimmy W. Mays, Nikos Hadjichristidis

United States Department of Energy: Publications

Single (SWNTs) and multiwalled (MWNTs) carbon nanotubes were functionalized with a titanium alkoxide catalyst through a Diels-Alder cycloaddition reaction. The catalyst-functionalized carbon nanotubes (CNTs) were used for the surface initiated titanium-mediated coordination polymerizations of L-lactide (L-LA), ε-caprolactone (ε-CL) and n-hexyl isocyanate (HIC) employing the “grafting from” technique. ¹H NMR, IR and Raman spectra showed that the precursor catalyst was successfully synthesized and covalently attached on the CNTs surface. Thermogravimetric analysis (TGA) revealed that the grafted poly(L-lactide) (PLLA) content could be controlled with time. The final polymer-grafted CNTs were readily dissolved in organic solvents as compared to the insoluble pristine …