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Full-Text Articles in Engineering

Development Of An Integrated Soil Properties Mapping System, Rajveer S. Dhillon Dec 2010

Development Of An Integrated Soil Properties Mapping System, Rajveer S. Dhillon

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

One of the main goals of precision agriculture (PA) is to define spatial variability in soil properties within an agricultural field to make decisions that can maximize profitability and reduce negative environmental impact. Various soil sensor systems have been developed over the years to map soil properties on-the-go. In this study, an Integrated Soil Mapping System (ISMS) was developed to predict soil water content, soil organic matter, and soil mechanical resistance on-the-go using a capacitance moisture sensor, an optical sensor, and a load cell sensor respectively. These sensors were mounted on the ISMS for acquiring three different data layers at …


Comparison Of Subsurface And Surface Runoff Phosphorus Transport Capacities In Alluvial Floodplains, Aaron R. Mittelstet, Derek M. Heeren, Daniel E. Storm, Garey A. Fox, M. J. White, R. B. Miller Nov 2010

Comparison Of Subsurface And Surface Runoff Phosphorus Transport Capacities In Alluvial Floodplains, Aaron R. Mittelstet, Derek M. Heeren, Daniel E. Storm, Garey A. Fox, M. J. White, R. B. Miller

Biological Systems Engineering: Papers and Publications

There have been numerous studies on phosphorus (P) contributions from surface runoff, but studies comparing the contribution of surface versus subsurface P are limited, as subsurface transport is often considered negligible. Previous work has shown that the transport of P in the gravelly subsurface at two sites in northeast Oklahoma can be significant, especially in preferential flow paths (PFPs), hypothesized to be buried gravel bars. The objective of this project was to quantify subsurface P losses based on field data, and compare with surface runoff P losses derived from Pasture Phosphorus Management Calculator (PPM Plus) simulations. Ozark ecoregion study sites …


Nutrient Transport In Runoff As Affected By Diet, Tillage, And Manure Application Rate, John E. Gilley, Lisa M. Durso, R.A. Eigenberg, David B. Marx, Brian L. Woodbury Nov 2010

Nutrient Transport In Runoff As Affected By Diet, Tillage, And Manure Application Rate, John E. Gilley, Lisa M. Durso, R.A. Eigenberg, David B. Marx, Brian L. Woodbury

Biological Systems Engineering: Papers and Publications

Feedlot operators may increase profitability by including distillers grains in finishing diets. However, the nutrients remaining in the by‐product are concentrated by about a factor of three during the distillation process. Manure can be applied to meet single‐ or multiple‐year crop nutrient requirements. The water quality effects of the use of distillers grains in feedlot diets and multiple‐year manure application have not been well quantified. The objectives of this study were to (1) compare the runoff water quality effects resulting from the application of manure derived from corn and distillers grain diets, (2) examine the effects of till and no‐till …


Enhanced Anthocyanin Extraction From Red Cabbage Using Pulsed Electric Field Processing, Tanya K. Gachovska, David A. Cassada, Jeyamkondan Subbiah, Milford Hanna, Harshavardhan Thippareddi, Daniel D. Snow Aug 2010

Enhanced Anthocyanin Extraction From Red Cabbage Using Pulsed Electric Field Processing, Tanya K. Gachovska, David A. Cassada, Jeyamkondan Subbiah, Milford Hanna, Harshavardhan Thippareddi, Daniel D. Snow

Biological Systems Engineering: Papers and Publications

This study was conducted to evaluate the effect of pulsed electric field (PEF) treatment on anthocyanin extraction from red cabbage using water as a solvent. Mashed cabbage was placed in a batch treatment chamber and subjected to PEF (2.5 kV/cm electric field strength; 15 μs pulse width and 50 pulses, specific energy 15.63 J/g). Extracted anthocyanin concentrations (16 to 889 μg/mL) were determined using HPLC. Heat and light stabilities of the control and PEF-treated samples, having approximately the same initial concentrations, were studied. PEF treatments enhanced total anthocyanin extraction in water from red cabbage by 2.15 times with a higher …


Multi-Robot System Control Architecture (Mrsca) For Agricultural Production, Santosh Pitla, Joe D. Luck, Scott A. Shearer Jun 2010

Multi-Robot System Control Architecture (Mrsca) For Agricultural Production, Santosh Pitla, Joe D. Luck, Scott A. Shearer

Department of Biological Systems Engineering: Conference Presentations and White Papers

Coordinating multiple autonomous robots for achieving an assigned collective task presents a complex engineering challenge. In this paper multi robot system control architecture (MRSCA) for the coordination of multiple agricultural robots is developed. The two important aspects of MRSCA; coordination strategy and inter-robot communication were discussed with typical agricultural tasks as examples. Classification of MRS into homogeneous and heterogeneous robots was done to identify appropriate form of cooperative behavior and inter-robot communication. The framework developed, proposes that inter-robot communication is not always required for a MRS. Three types of cooperative behaviors; No-cooperation, modest cooperation and absolute cooperation for a MRS …


Pneumatic Control Of A Variable Orifice Nozzle, Joe D. Luck, Michael P. Sama, Santosh Pitla, Scott A. Shearer Jun 2010

Pneumatic Control Of A Variable Orifice Nozzle, Joe D. Luck, Michael P. Sama, Santosh Pitla, Scott A. Shearer

Department of Biological Systems Engineering: Conference Presentations and White Papers

A variable-orifice nozzle with droplet optimization was recently developed and introduced for use on agricultural sprayers. The VariTarget (VT) nozzle reacts to changes in the system flow rate via a metering assembly that is controlled by a diaphragm and spring. As the liquid pressure changes, the VT metering assembly attempts to control the flow rate and spray pattern exiting the nozzle. The goal of this study was to replace the spring controlled “reactive” system with a pneumatically controlled metering assembly. The proposed system would allow for the metering assembly to adjust the flow rate and spray pattern exiting the nozzle …


Geophysical Mapping Of Preferential Flow Paths Across Multiple Floodplains, Ronald B. Miller, Derek M. Heeren, Garey A. Fox, Daniel E. Storm, Todd Halihan, Aaron R. Mittelstet Jun 2010

Geophysical Mapping Of Preferential Flow Paths Across Multiple Floodplains, Ronald B. Miller, Derek M. Heeren, Garey A. Fox, Daniel E. Storm, Todd Halihan, Aaron R. Mittelstet

Biological Systems Engineering: Papers and Publications

In the Ozark ecoregion of Oklahoma, Arkansas and Missouri, the erosion of carbonate bedrock (primarily limestone) by slightly acidic water has left a residuum of chert gravel, producing gravel-bed streams and floodplains generally consisting of coarse chert gravel overlain by a mantle (1 to 300 cm) of gravelly loam or silt loam. Previous research has documented the occurrence of preferential flow paths (PFP) in an alluvial floodplain hypothesized to be a buried gravel bar. Field experiments have shown that the PFP affected alluvial groundwater flow in the floodplain and that water flow in the PFP was transmitted at rates that …


Impact Of Preferential Flow Paths On Alluvial Groundwater Flow Patterns And Phosphorus Transport, Derek M. Heeren, Ronald B. Miller, Garey A. Fox, Daniel E. Storm, Aaron R. Mittelstet, Chad J. Penn Jun 2010

Impact Of Preferential Flow Paths On Alluvial Groundwater Flow Patterns And Phosphorus Transport, Derek M. Heeren, Ronald B. Miller, Garey A. Fox, Daniel E. Storm, Aaron R. Mittelstet, Chad J. Penn

Biological Systems Engineering: Papers and Publications

While surface runoff is considered to be the primary transport mechanism for phosphorus (P), subsurface transport through coarse subsoil to gravel bed streams may be significant and represent a source of P not alleviated by current conservation practices (e.g., riparian buffers). Previous research has documented P transport in a preferential flow path (PFP) identified as a buried gravel bar. It is hypothesized that PFPs, if connected to the soil surface, provide a rapid and efficient method of transporting P, and that these alluvial features are transient storage zones for nutrients, acting as a sink during high flow and a source …


Optimization And Economic Evaluation Of Industrial Gas Production And Combined Heat And Power Generation From Gasification Of Corn Stover And Distillers Grains, Ajay Kumar, Yaşar Demirel, David D. Jones, Milford Hanna May 2010

Optimization And Economic Evaluation Of Industrial Gas Production And Combined Heat And Power Generation From Gasification Of Corn Stover And Distillers Grains, Ajay Kumar, Yaşar Demirel, David D. Jones, Milford Hanna

Biological Systems Engineering: Papers and Publications

Thermochemical gasification is one of the most promising technologies for converting biomass into power, fuels and chemicals. The objectives of this study were to maximize the net energy efficiency for biomass gasification, and to estimate the cost of producing industrial gas and combined heat and power (CHP) at a feedrate of 2,000 kg/h. Aspen Plusbased model for gasification was combined with a CHP generation model, and optimized using corn stover and dried distillers grains with solubles (DDGS) as the biomass feedstocks. The cold gas efficiencies for gas production were 57% and 52%, respectively, for corn stover and DDGS. The selling …


Nutrient Transport In Runoff From Feedlots As Affected By Wet Distillers Grain Diet, John E. Gilley, Jason R. Vogel, Roger A. Eigenberg, David B. Marx, Brian L. Woodbury Mar 2010

Nutrient Transport In Runoff From Feedlots As Affected By Wet Distillers Grain Diet, John E. Gilley, Jason R. Vogel, Roger A. Eigenberg, David B. Marx, Brian L. Woodbury

Biological Systems Engineering: Papers and Publications

Distillers byproducts can serve as valuable sources of protein and energy for beef cattle. However, the water quality effects of the use of distillers byproducts in cattle rations are not well understood. The objectives of this study were to: (1) measure soil properties and nutrient transport in runoff from feedlot surfaces as affected by corn‐based and wet distillers grain diets, (2) compare the effects of unconsolidated surface materials and consolidated subsurface materials on feedlot soil characteristics and runoff nutrient transport, (3) determine if runoff nutrient transport from feedlot surfaces is correlated to selected feedlot soil properties, and (4) identify the …


Reducing The Cost Of Pumping Irrigation Water, Derrel L. Martin, William L. Kranz, Tom W. Dorn, Steve R. Melvin, Alan J. Corr Feb 2010

Reducing The Cost Of Pumping Irrigation Water, Derrel L. Martin, William L. Kranz, Tom W. Dorn, Steve R. Melvin, Alan J. Corr

Department of Biological Systems Engineering: Conference Presentations and White Papers

Irrigation accounts for a large portion of the energy used in Nebraska agriculture. The cost to pump irrigation water depends on the type of energy used to power the pumping unit. This document describes a method to estimate the cost of pumping water and to compare the amount of energy used to that for a well maintained and designed pumping plant. The results can help determine the feasibility of repairing the pumping plant.


Updating The Nebraska Pumping Plant Performance Criteria, William Kranz, Derrel L. Martin, Dean Patterson, Jerry Hudgins, Simon Van Donk, C. Dean Yonts Feb 2010

Updating The Nebraska Pumping Plant Performance Criteria, William Kranz, Derrel L. Martin, Dean Patterson, Jerry Hudgins, Simon Van Donk, C. Dean Yonts

Department of Biological Systems Engineering: Conference Presentations and White Papers

Irrigation water is removed from groundwater storage using deep well turbine pumps powered by electric motors or diesel, gasoline, propane, ethanol, or natural gas internal combustion engines. For best operating efficiency irrigation power units are selected to specifically meet the requirements of the irrigation system that include how deep the water in the well is under pumping conditions, the water pressure required at the pump outlet, and the system flow rate. The evaluation of pumping plants to establish pumping plant performance dates back into the 1950’s when researchers at the University of Nebraska were unable to directly compare the operation …


Cytotoxicity Of Bacterial-Derived Toxins To Immortal Lung Epithelial And Macrophage Cells, Dianne E. Peterson, Jayne M. Collier, Matthew E. Katterman, Rachel A. Turner, Mark R. Riley Feb 2010

Cytotoxicity Of Bacterial-Derived Toxins To Immortal Lung Epithelial And Macrophage Cells, Dianne E. Peterson, Jayne M. Collier, Matthew E. Katterman, Rachel A. Turner, Mark R. Riley

Biological Systems Engineering: Papers and Publications

Health risks associated with inhalation and deposition of biological materials have been a topic of great concern due to highly publicized cases of inhalation anthrax, of new regulations on the release of particulate matter, and to increased concerns on the hazards of indoor air pollution. Here, we present an evaluation of the sensitivity of two immortal cell lines (A549, human lung carcinoma epithelia) and NR8383 (rat alveolar macrophages) to a variety of bacterial-derived inhalation hazards and simulants including etoposide, gliotoxin, streptolysin O, and warfarin. The cell response is evaluated through quantification of changes in mitochondrial succinate dehydrogenase activity, release of …


2010 Nebraska Water Monitoring Programs Report, Marty Link Jan 2010

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.


Linearized Theory Of Peridynamic States, S. A. Silling Jan 2010

Linearized Theory Of Peridynamic States, S. A. Silling

US Department of Energy Publications

A state-based peridynamic material model describes internal forces acting on a point in terms of the collective deformation of all the material within a neighborhood of the point. In this paper, the response of a state-based peridynamic material is investigated for a small deformation superposed on a large deformation. The appropriate notion of a small deformation restricts the relative displacement between points, but it does not involve the deformation gradient (which would be undefined on a crack). The material properties that govern the linearized material response are expressed in terms of a new quantity called the modulus state. This determines …


Nebraska Statewide Wind Integration Study: Executive Summary April 2008 – January 2010, Enernex Corporation Knoxville, Tennessee, Ventyx Atlanta, Georgia, Nebraska Power Association Lincoln, Nebraska Jan 2010

Nebraska Statewide Wind Integration Study: Executive Summary April 2008 – January 2010, Enernex Corporation Knoxville, Tennessee, Ventyx Atlanta, Georgia, Nebraska Power Association Lincoln, Nebraska

US Department of Energy Publications

Wind generation is a source of electric energy that, in sufficient quantity, can cause concern for the operation of the bulk power system because of the variability and uncertainty of the wind. Most short-term planning and operational functions supporting the electric power grid are centered on supply resources that have capacity attributes – i.e. they can be dispatched (controlled up and down) to a specified power level for a specified period of time. The need to maintain very high levels of system reliability reinforces the preference in operations toward resources having capacity attributes. Wind generation usually has relatively low capacity …


Validation Of A Model For Static And Dynamic Recrystallization In Metals, Arthur Brown, Douglas Bammann Jan 2010

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

US 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 Jan 2010

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

US 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 …


Microbial And Mineralogical Characterizations Of Soils Collected From The Deep Biosphere Of The Former Homestake Gold Mine, South Dakota, Gurdeep Rastogi, Shariff Osman, Ravi K. Kukkadapu, Mark Engelhard, Parag A. Vaishampayan, Gary L. Andersen, Rajesh K. Sani Jan 2010

Microbial And Mineralogical Characterizations Of Soils Collected From The Deep Biosphere Of The Former Homestake Gold Mine, South Dakota, Gurdeep Rastogi, Shariff Osman, Ravi K. Kukkadapu, Mark Engelhard, Parag A. Vaishampayan, Gary L. Andersen, Rajesh K. Sani

US Department of Energy Publications

A microbial census on deep biosphere (1.34 km depth) microbial communities was performed in two soil samples collected from the Ross and number 6Winze sites of the former Homestake gold mine, Lead, South Dakota using high-density 16S microarrays (PhyloChip). Soil mineralogical characterization was carried out using X-ray diffraction, X-ray photoelectron, and Mössbauer spectroscopic techniques which demonstrated silicates and iron minerals (phyllosilicates and clays) in both samples. Microarray data revealed extensive bacterial diversity in soils and detected the largest number of taxa in Proteobacteria phylum followed by Firmicutes and Actinobacteria. The archael communities in the deep gold mine environments were …


Microbial Reduction Of Uranium Under Iron- And Sulfate-Reducing Conditions: Effect Of Amended Goethite On Microbial Community Composition And Dynamics, H.S. Moon, L. Mcguinness, Ravi K. Kukkadapu, A.D. Peacock, John Komlos, L.J. Kerkhof, P.E. Long, Peter R. Jaffe Jan 2010

Microbial Reduction Of Uranium Under Iron- And Sulfate-Reducing Conditions: Effect Of Amended Goethite On Microbial Community Composition And Dynamics, H.S. Moon, L. Mcguinness, Ravi K. Kukkadapu, A.D. Peacock, John Komlos, L.J. Kerkhof, P.E. Long, Peter R. Jaffe

US Department of Energy Publications

There is a growing need for a better understanding of the biogeochemical dynamics involved in microbial U(VI) reduction due to an increasing interest in using biostimulation via electron donor addition as a means to remediate uranium contaminated sites. U (VI) reduction has been observed to be maximized during iron-reducing conditions and to decrease upon commencement of sulfate-reducing conditions. There are many unknowns regarding the impact of iron/sulfate biogeochemistry on U(VI) reduction. This includes Fe(III) availability as well as the microbial community changes, including the activity of iron-reducers during the uranium biostimulation period even after sulfate reduction becomes dominant. Column experiments …


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 Jan 2010

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

US 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 …


Load-Locked Dc High Voltage Gaas Photogun With An Inverted-Geometry Ceramic Insulator, P. A. Adderley, J. Clark, J. Grames, J. Hansknecht, K. Surles-Law, D. Machie, M. Poelker, M. L. Stutzman, R. Suleiman Jan 2010

Load-Locked Dc High Voltage Gaas Photogun With An Inverted-Geometry Ceramic Insulator, P. A. Adderley, J. Clark, J. Grames, J. Hansknecht, K. Surles-Law, D. Machie, M. Poelker, M. L. Stutzman, R. Suleiman

US Department of Energy Publications

A new dc high voltage spin-polarized photoelectron gun has been constructed that employs a compact inverted-geometry ceramic insulator. Photogun performance at 100 kV bias voltage is summarized.

I. INTRODUCTION

All of the nuclear physics experiments conducted at the Continuous Electron Beam Accelerator Facility (CEBAF) at the Thomas Jefferson National Accelerator Facility (Jefferson Lab) receive electron beams from a dc high voltage spin-polarized GaAs photoemission gun. Since 1995, the year the first polarized electron source was installed at CEBAF [1], there have been four different photogun designs with each new gun an improvement over its predecessor. The most recent design employs …


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 Jan 2010

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

US Department of Energy Publications

Absolute photoionization measurements were performed for a mixture of 2Po3/2 ground-state and 2Po1/2 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 2Po3/2 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 …


Confinement Resonances In Photoionization Of Xe@C+60, A. L. D. Kilcoyne, A. Aguilar, A. Muller, S. Schippers, C. Cisneros, G. Alna’Washi, N. B. Aryal, K. K. Baral, D. A. Esteves, C. M. Thomas, R. A. Phaneuf Jan 2010

Confinement Resonances In Photoionization Of Xe@C+60, A. L. D. Kilcoyne, A. Aguilar, A. Muller, S. Schippers, C. Cisneros, G. Alna’Washi, N. B. Aryal, K. K. Baral, D. A. Esteves, C. M. Thomas, R. A. Phaneuf

US Department of Energy Publications

Experimental evidence is presented for confinement resonances associated with photoabsorption by a Xe atom in a C60 cage. The giant 4d resonance in photoionization of Xe is predicted to be redistributed into four components due to multipath interference of photoelectron waves reflected by the cage. The measurements were made in the photon energy range 60–150 eV by merging a beam of synchrotron radiation with a mass/charge selected Xe@C+60 ion beam. The phenomenon was observed in the Xe@C3+58 product ion channel.


Ellipsometric Study Of Single-Crystal Γ-Inse From 1.5 To 9.2 Ev, S. G. Choi, D. E. Aspnes, A. L. Fuchser, C. Martinez-Tomas, V. Muñoz Sanjosé, D. H. Levi Jan 2010

Ellipsometric Study Of Single-Crystal Γ-Inse From 1.5 To 9.2 Ev, S. G. Choi, D. E. Aspnes, A. L. Fuchser, C. Martinez-Tomas, V. Muñoz Sanjosé, D. H. Levi

US Department of Energy Publications

We report the component Ec of the pseudodielectric-function tensor <ε(E)> = <ε1(E)> + i< ε2(E)> of γ-phase single-crystal InSe, obtained from 1.5 to 9.2 eV by vacuum-ultraviolet spectroscopic ellipsometry with the sample at room temperature. Overlayer artifacts were reduced as far as possible by measuring fresh surfaces prepared by cleavage. Accurate critical-point energies of observed structures were obtained by a combined method of spectral analysis.


Heating Performance Assessment Of Domestic Microwave Ovens, Krishnamoorthy Pitchai, Sohan Birla, Jeyamkondan Subbiah, David D. Jones Jan 2010

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

Department of Biological Systems Engineering: Conference 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 …


Effect Of Magnetron Frequency On Heating Pattern In Domestic Oven, Sohan Birla, Krishnamoorthy Pitchai, Jeyamkondan Subbiah, David D. Jones Jan 2010

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

Department of Biological Systems Engineering: Conference 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 …


Low-Cost Obstacle Detection Sensor Array For Unmanned Agricultural Vehicles, Santosh Pitla, Joe D. Luck, Scott A. Shearer Jan 2010

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

Department of Biological Systems Engineering: Conference 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 …


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 Jan 2010

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 Biological Systems Engineering: Conference 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 …


Testing Fuel Efficiency Of Tractors With Both Continuously Variable And Standard Geared Transmissions, Christopher N. Howard Jan 2010

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 …