Engineering Commons^™

A Multiwavelength Airborne Polarimetric Lidar For Vegetation Remote Sensing: Instrumentation And Preliminary Test Results, Songxin Ran, Ram M. Narayanan

Department of Electrical and Computer Engineering: Faculty Publications

Several spaceborne and airborne lidar systems have been launched for vegetation canopy studies. Previous research has shown that lidars are useful tools for remote sensing of vegetation architecture. To support its Airborne Remote Sensing Program, the University of Nebraska has developed a multiwavelength airborne polarimetric lidar system. This system employs a Nd:YAG laser which emits radiation at two wavelengths: the fundamental at 1064 nm and the frequency-doubled at 532 nm. Both laser beams are highly linearly polarized (100: 1 extinction ratio) and have a beam divergence angle of ~4 mrad. The receiver consists of four channels, which enable dual-wavelength and …

Femtosecond Laser Utilization Methods And Apparatus And Method For Producing Nanoparticles, Dennis R. Alexander

Department of Electrical and Computer Engineering: Faculty Publications

The present invention teaches various femtosecond machining and drilling apparatus and processes for fabricating tools and the like from both traditional and non-traditional materials. Also described are novel tools such as scalpels, and nozzles fabricated from the apparatus and processes of the present invention. Likewise, the present invention may be utilized in both a novel propulsion system and the production of materials formed from nanometer sized particles and the like.

Prediction Of Soakout Time Using Analytical Models, B. Chakravarthy, H. P. Cherukuri, R. G. Wilhelm

Department of Mechanical and Materials Engineering: Faculty Publications

In precision manufacturing enterprises, machine parts at nonstandard temperatures are often soaked to standard temperature prior to making any dimensional measurements. The soakout times are usually determined using lumped heat-transfer models where the part temperatures are assumed to be uniform. This article discusses conditions under which lumped model assumptions are valid by comparing lumped analyses for various shapes and materials with the more general finite element results. In addition, the effect of ambient temperature cycling on part response is also studied.

Report On An Aeromagnetic Survey Of The Missouri National Recreational River: Data Acquisition, Geopbysical Processing, And Base Map Interpretation, Brian L. Molyneaux

United States Army Corps of Engineers, Omaha District

The University of South Dakota Archaeology Laboratory, with the support of the Missouri River Institute, conducted an airborne magnetic survey of the Missouri National Recreational River for the US Army Corps of Engineers, Omaha District, (contract #DACW45-01-P-0267, supervised by Rebecca Latka, Project Manager, Missouri National Recreational River). The primary goal was to identify buried or submerged cultural resources along the past and present Missouri River channel.

The Principal Investigator was Brian Leigh Molyneaux, PhD. TerraQuest Ltd., Mississauga, Ontario, Canada, an international specialist in airborne geophysical surveys, acquired the total field magnetic data between November 27 and December 12, 2001. CGI …

An Evaluation Of Sampling Techniques And Life History Information On Biguead Carp In The Missouri River, Below Gavlns Point Dam, South Dakota And Nebraska

United States Army Corps of Engineers, Omaha District

Bighead carp Hypopthmichtys nobilis were introduced into the United States from south and central China (Robins et al. 1991) in 1972 (Henderson 1979).  It is an efficient planktivore (Henderson 1978) that was imported into Arkansas by an aquaculturist to improve water quality in catfish ponds (Henderson 1976).  In 1974, the Arkansas Game and Fish Commission began looking at potential impacts of bighead and other Asian carp as well as their beneficial effects on the environment.  Regulations were also imposed to prevent these fish from entering public waters from private sources (Henderson 1975).  In 1981, nevertheless, the first bighead carp was …

Diet Of Shovelnose Sturgeon Downstream From Gavins Point Dam: Final Report, Charles R. Berry Jr.

United States Army Corps of Engineers, Omaha District

The diet of shovelnose sturgeon (Scaphirhynchus platorhynchus) in the Missouri River downstream from Gavins Point Dam was characterized in 1993 (N=100 fish) and 1994 (N=103 fish) for comparison with similar data collected in 1971-72 (N=130 fish) by Modde and Schmulbach (1977, hereafter Modde). The primary difference among years in the South Dakota studies was river discharge, which was low in 1993 (9-22 kcfs; kcfs=thousand cubic feet per second), moderate in 1994 (18-31 kcfs), and high in 1971-72 (26-49 kcfs). We compared sturgeon diet weight and the weight of benthic and drifting invertebrates among years, among monthly discharges in …

Shovelnose Sturgeon Lridovirus Sampling In The Missouri River, Below Gavins Point Dam, South Dakota And Nebraska

United States Army Corps of Engineers, Omaha District

Numerous sturgeon species have been integral components of significant fisheries within North America. Species of sturgeon have played an important historical role in recreational and commercial fisheries of various riverine and Great Lakes communities throughout the United States. Present commercial fisheries for sturgeon species are virtually non-existent, in part due to overexploitation, coupled with an inherently long period of time for sturgeon species to become sexually mature.

Two species within the Missouri River basin (pallid sturgeon, Scaphirhynchus albus) and shovelnose sturgeon, Scaphirhynchus platorynchus) have been recently found to harbor a suspect virus (currently being referred to as the …

Summary Report: Evaluation Of The Benthic Trawl As A Means To Sample Juvenile And Adult Pallid Sturgeon From Main Channel Habitats Of The Missouri River, Gerald Mestl

United States Army Corps of Engineers, Omaha District

The Missouri River forming the border between Nebraska and South Dakota, Iowa, and Missouri. The upper unchannelized reach extends from the Nebraska-South Dakota state line (river kilometer (rkm) 1,411) to the upper end of Lewis and Clark Lake (rkm 1,347). The lower unchannelized reach extends from Gavins Point Dam (rkm 1 ,308) to the mouth of the Big Sioux River (rkm 1,184). The upper channelized reach extends from the mouth of the Big Sioux River (rkm 1,184) to the mouth of the Platte River (rkm 959). The lower channelized reach extends from the mouth of the Platte River (rkm 959) …

Chemical Partitioning During Crystallization And Its Effect On The Microstructure And Magnetic Behavior Of Modified Nd–Fe–B Permanent Magnets, Jeffrey E. Shield, B. B. Kappes, D. J. Branagan, J. Bentley

Department of Mechanical and Materials Engineering: Faculty Publications

In this paper, the effect of alloy composition on the microstructural development of devitrified Nd–Fe–B-based alloys is investigated. While crystallization of simple ternary Nd₂Fe₁₄B resulted in a highly variable microstructure and relatively poor demagnetization behavior, alloying additions, notably Ti and C, were found to significantly refine and homogenize the crystallized microstructure. High spatial resolution energy dispersive X-ray spectroscopy revealed that partitioning to the grain boundaries led to the grain refinement by slowing interface kinetics. The more homogeneous grain structure resulted in improved demagnetization behavior, but segregating elements isolated grains and limited intergranular exchange coupling.

Immobilization Of Pseudomonas Cepacia Lipase By Sol-Gel Entrapment And Its Application In The Hydrolysis Of Soybean Oil, Hossein Noureddini, X Gao, S Joshi, P R. Wagner

Papers in Biomaterials

The immobilization of Lipase PS from Pseudomonas cepacia by entrapment within a chemically inert hydrophobic sol-gel support was studied. The gel-entrapped lipase was prepared by the hydrolysis of tetramethoxysilane (TMOS) with methyltrimeth-oxysilane (MTMS), isobutyltrimethoxysilane (iso-BTMS), and n-butyltrimethoxysilane. The immobilized lipase was subsequently used in the hydrolysis of soybean oil to determine its activity, recyclability, and thermostability. The biocatalyst so prepared was equal to or better than the free enzyme in its hydrolytic activity. The catalytic activity of the entrapped lipase strongly depended on the type of precursor that was used in its preparation. The lipase entrapped within TMOS/iso-BTMS showed the …

A Physically Based Two-Dimensional Infiltration Model For Furrow Irrigation, Christopher J. Skonard, Derrel L. Martin

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

A two-dimensional physically based infiltration model was developed for furrow
irrigation. Infiltration was simulated using the Green-Ampt infiltration method. The Green-Ampt infiltration parameters are available from numerous sources, unlike the Kostiakov infiltration parameters. Simulation tests showed the two-dimensional model capable of estimating cumulative infiltration volume within 8% compared to simulated infiltration using the finite element model, Hydrus-2D. Application of the two-dimensional model in a surface irrigation advance model allows irrigation performance parameters to be predicted without extensive soil experiments.

Heat Curing Of Soy Protein Films At Selected Temperatures And Pressures, Ki Myong Kim, Curtis Weller, Milford Hanna, Aristippos Gennadios

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Vacuum and temperature effects on moisture content, water vapor permeability (WVP), color (L, a, b, and DE), tensile strength (TS), elongation (E), and total soluble matter (TSM) of soy protein isolate (SPI) films were examined. SPI films were cured at 60, 72.5, or 85 °C and at 101.3, 81.32, or 61.32 kPa for 24 h. As a result of heat-curing moisture content, WVP, E, and TSM decreased, and total color difference and TS increased. Pressure, individually and interactively with temperature, significantly affected film moisture content, TS, and TSM.

Manure As Carbon Source For Soil Improvement And Crop Production: Site-Specific Application, Bahman Eghball, Daniel Ginting, Charles A. Shapiro, James S. Schepers, Christopher J. Bauer

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Manure, a renewable resource, is an excellent source of nutrients that can be substituted for synthetic types of fertilizers. The C in manure can enhance the physical and chemical properties of soils, especially infertile soils, as these soils typically contain low levels of organic matter and nutrients. The objective of this study was to evaluate the effects of C and nutrients in manure on soil C dynamics and crop production. The treatments included applications of site-specific manure (SSM), uniform manure (UM), uniform commercial fertilizer, and a no treatment check. Field strips 40 ft (16 corn rows) wide and 2200 ft …

Impact Of Manure Application On Phosphorus Runoff And Soil Erosion, Daniel T. Walters, C. Gossin, Gregory J. Teichmeier, Galen E. Erickson

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Phosphorus (P) losses from agricultural land is a serious environmental issue because of the impact of P on freshwater eutrophication (McDowell, et al., 2001). The movement of P from soil to surface water is impacted by P input to soil and manure management practices that impact P transport processes. Twenty-one natural runoff plots were established to monitor the effect of time and method of composted beef feedlot manure application and feed P input on net losses of bio-available P and sediment in surface runoff. Reducing feed P inputs resulted in a 33% reduction in manure P content. Runoff losses of …

Ft-Nir Spectroscopic Analysis Of Nitrogen In Cotton Leaves, Mark R. Riley, Loreto C. Canaves

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Near-infrared spectroscopy was evaluated as a means to quantify the nitrogen content- in fresh cotton leaves (Gossypium hirsutum L. var. Delta Pine 90) subjected to a factorial design experiment of varying nitrogen and water applications. Absorbance spectra were collected in the 10000-4000 cm^-1 (1000-2500 nm) region from fresh cotton leaves over a two month portion of the growing season. Total nitrogen content was quantified by a wet chemistry Kjeldahl method for validation purposes. Partial least-squares regression analysis, using an automated grid search method, selected the spectral region 6041 to 5651 cm^-1 (1650-1770 nm) for analysis based on having …

Making Agents Secure On The Semantic Web, Csilla Farkas, Michael N. Huhns

Faculty Publications

Agents were designed to collaborate and share information. While highly desirable for interoperability, this feature is scary from the security perspective. Illegal inferences, supported by semantic Web technology and ontologies, might enable users to access unauthorized information. In addition to semantic associations and replicated data with different sensitivity, malicious agents could also exploit statistical inferences. Although each agent in a system might behave in a desired and secure way, their combined knowledge could be used to disclose sensitive data. The research community must therefore develop and implement techniques that allow control over released data. To answer the questions related to …

Estimation Of Diffusion Coefficient Of Lithium In Carbon Using Ac Impedance Technique, Qingzhi Guo, Venkat R. Subramanian, John W. Weidner, Ralph E. White

Faculty Publications

The validity of estimating the solid phase diffusion coefficient, D_s, of a lithium intercalation electrode from impedance measurement by a modified electrochemical impedance spectroscopy (EIS) method is studied. A macroscopic porous electrode model and concentrated electrolyte theory are used to simulate the synthetic impedance data. The modified EIS method is applied for estimating D_s. The influence of parameters such as the exchange current density, radius of active material particle, solid phase conductivity, porosity, volume fraction of inert material, and thickness of the porous carbon intercalation electrode, the solution phase diffusion coefficient, and transference number, on the …

Using Sputter Deposition To Increase Co Tolerance In A Proton-Exchange Membrane Fuel Cell, Andrew T. Haug, Ralph E. White, John W. Weidner, Wayne Huang, Steven Shi, Narender Rana, Stephan Grunow, Timothy C. Stoner, Alain E. Kaloyeros

Faculty Publications

Placing a layer of Ru atop a Pt anode increases the carbon monoxide tolerance of proton-exchange membrane fuel cells when oxygen is added to the fuel stream. Sputter-deposited Ru filter anodes composed of a single Ru layer and three Ru layers separated by Nafion-carbon ink, respectively, were compared to Pt, Pt:Ru alloy, and an ink-based Ru filter anodes. The amount of Pt in each anode was 0.15 mg/cm² and the amount of Ru in each Ru-containing anode was 0.080 mg/cm². For an anode feed consisting of hydrogen, 200 ppm CO, and 2% O₂ (in the form …

Increasing Proton Exchange Membrane Fuel Cell Catalyst Effectiveness Through Sputter Deposition, Andrew T. Haug, Ralph E. White, John W. Weidner, Wayne Huang, Steven Shi, Timothy Stoner, Narender Rana

Faculty Publications

Sputter deposition has been investigated as a tool for manufacturing proton-exchange membrane fuel cell (PEMFC) electrodes with improved performance and catalyst utilization vs. ink-based electrodes. Sputter-depositing a single layer of Pt on the gas diffusion layer provided better performance (0.28 A/cm² at 0.6 V) than sputtering the Pt directly onto a Nafion membrane (0.065 A/cm² at 0.6 V) and equaled the performance of the baseline for an equivalent Pt loading. Sputter-depositing alternating layers of Pt and Nafion-carbon ink (NCI) onto the membrane did not increase the performance over the baseline as measured in amperes per centimeter squared due …

Simulating Shape Changes During Electrodeposition: Primary And Secondary Current Distribution, Venkat R. Subramanian, Ralph E. White

Faculty Publications

A technique based on the analytical method of lines is presented for predicting shape changes during electrodeposition. The technique is presented for both primary and secondary current distributions. The method presented does not require iterations for nonlinear Butler-Volmer boundary conditions or changing electrode shapes. The technique is based on a semianalytical method developed earlier for predicting current distributions in electrochemical cells. This technique is attractive because it provides a symbolic solution for the Laplace equation, and hence requires less computation time to perform case studies.

Electrochemical Filtering Of Co From Fuel-Cell Reformate, Balasubramanian Lakshmanan, Wayne Huang, John W. Weidner

Faculty Publications

A proton exchange membrane fuel cell was used as a flow reactor for continuous preferential oxidation of CO over H2 from 1.0% CO in H2 under pulse-potential control. By varying the pulse profile ~e.g., on-time, off-time, pulse potential! the CO and H2 oxidation currents were varied independently. The improvement in faradaic selectivity between CO and H2 oxidation results from the promotion of CO adsorption during the off ~i.e., open-circuit! portion of the pulse. Therefore, during the on portion CO oxidation was preferred while the surface was covered with CO.

Anodic Behavior Of Ti In Koh Solutions: Ellipsometric And Micro-Raman Spectroscopy Studies, A. Prusi, Lj. Arsov, Bala Haran, Branko N. Popov

Faculty Publications

Anodic formation of oxide films on titanium surfaces, in various concentrations of aqueous KOH solutions, have been studied using ellipsometry and micro-Raman spectroscopy. By in situ ellipsometric measurements the coefficient of film thickness growth and indexes of refraction of anodic oxide films have been determined. The voltage at which the oxide film breaks down is strongly dependent on the KOH concentration. Further, the solution concentration strongly influences the potential at which the oxide film is transformed from the amorphous state to crystalline form. Using micro-Raman spectroscopy four crystalline forms of titanium oxides, namely, anatase, brookite, corundum, and rutile, have been …

Study Of Sn-Coated Graphite As Anode Material For Secondary Lithium-Ion Batteries, Basker Veeraraghavan, Anand Durairajan, Bala Haran, Branko N. Popov, Ronald Guidotti

Faculty Publications

Tin-graphite composites have been developed as an alternate anode material for Li-ion batteries using an autocatalytic deposition technique. The specific discharge capacity, coulombic efficiency, rate capability behavior, and cycle life of Sn-C composites has been studied using a variety of electrochemical methods. The amount of tin loading and the heating temperature have a significant effect on the composite performance. The synthesis conditions and Sn loading on graphite have been optimized to obtain the maximum reversible capacity for the composite electrode. Heating the composite converts it from amorphous to crystalline form. Apart from higher capacity, Sn-graphite composites possesses higher coulombic efficiency, …

Modeling The Effects Of Electrode Composition And Pore Structure On The Performance Of Electrochemical Capacitors, Changqing Lin, Branko N. Popov, Harry J. Ploehn

Faculty Publications

This work presents a mathematical model for charge/discharge of electrochemical capacitors that explicitly accounts for particle-packing effects in a composite electrochemical capacitor consisting of hydrous RuO₂ nanoparticles dispersed within porous activated carbon. The model is also used to investigate the effect of nonuniform distributions of salt in the electrolyte phase of the electrode in the context of dilute solution theory. We use the model to compare the performance of capacitors with electrodes made from different activated carbons and to investigate the effects of varying carbon content and discharge current density. Even at low discharge current density, concentration polarization in …

Modeling The Effects Of Electrode Composition And Pore Structure On The Performance Of Electrochemical Capacitors, Changqing Lin, Branko N. Popov, Harry J. Ploehn

Faculty Publications

This work presents a mathematical model for charge/discharge of electrochemical capacitors that explicitly accounts for particle-packing effects in a composite electrochemical capacitor consisting of hydrous RuO₂ nanoparticles dispersed within porous activated carbon. The model is also used to investigate the effect of nonuniform distributions of salt in the electrolyte phase of the electrode in the context of dilute solution theory. We use the model to compare the performance of capacitors with electrodes made from different activated carbons and to investigate the effects of varying carbon content and discharge current density. Even at low discharge current density, concentration polarization in …

Surface Micromachined Force Gauges: Uncertainty And Reliability, Jonathan W. Wittwer, Troy Gomm, Larry L. Howell

Faculty Publications

Surface micromachining of micro-electro-mechanical systems (MEMS), like all other fabrication processes, has inherent variation that leads to uncertain material and dimensional parameters. By considering the effects of these variations during the design of micro force gauges, the gauge uncertainty and reliability can be estimated. Without means of calibrating micro gauges, these effects are often significant when compared to experimental repeatability. The general force gauge model described in this paper can be used to measure a wide range of forces, and simple design changes can lead to improved accuracy in measurement. A method of probabilistic design is described that is not …

Evaluation Of A Compound Probability Model With Tower-Mounted Scatterometer Data, David G. Long, Benjamin E. Barrowes

Faculty Publications

Six months of data from the YSCAT94 experiment conducted at the CCIW WAVES research platform on Lake Ontario, Canada, are analyzed to evaluate a compound probability model. YSCAT was an ultrawideband small footprint (ap 1 m) microwave scatterometer that operated at frequencies of 2-18 GHz, incidence angles from 0° to 60°, both h-pol and v-pol, and which tracked the wind using simultaneous weather measurements. The probability distribution function of the measured instantaneous backscattered amplitude (p(a)) is compared to theoretical distributions developed from-the composite model and a simple wave spectrum. Model parameters of the resulting Rayleigh/generalized lognormal distribution probability density function …

The Effects Of An Interactive Computerized Multimedia Tutorial On Knowledge Gain In Modular Fixturing Design Concepts, Veekit O'Charoen

Dissertations and Theses @ UNI

This study was designed to compare student knowledge gain from learning modular fixturing design concepts by computer tutorial versus traditional lecture. The use of computer tutorial to support engineering and technology classroom instructions has been a major issue for many studies. The undergraduate curricula in engineering and technology are becoming increasingly complex due to the today's modern wide variety of manufacturing processes. The concept of modular fixturing in tool design course is one of the technical competencies which most industries would like graduates to be able to apply their knowledge to real-world problems and situations.

An interactive computerized multimedia tutorial …

Application Of Artificial Neural Networks To Sensitivity Analysis And Modeling Of Small Office Buildings, Quan Tang

Dissertations and Theses @ UNI

Sensitivity analysis and Multiple Linear Regression (MLR) are the most extensively used techniques in studying the input-output relationship in building thermal systems. However, both MLR and most methods for sensitivity analysis do not account for nonlinear components embedded in building energy systems. Thus, their results might be distorted.

In this study, the Artificial Neural Networks (ANN) technique was applied to sensitivity analysis and modeling of an imaginary small office in order to (a) examine how the annual energy consumption responded to 40 building design parameters and evaluate relative contributions of these parameters to the variation of the building energy performance, …

Spectral Integration Of Microstructure And Design, Brent L. Adams, B. Henrie, M. Lyon, H. Garmestani, Surya R. Kalidindi

Faculty Publications

Support of the Army Research Office is greatly appreciated. Mechanical design can be conducted in a framework where consideration of microstructure as a continuous design variable is facilitated by the use of a Fourier space. Selection of the mechanical framework for the problem (e.g., mechanical constitutive model and homogenization relations) dictates the dimensionality of the pertinent microstructure representation. Microstructure is comprised of basic elements that belong to the local state space. Local state includes crystallographic phase and orientation, and other parameters such as composition. The local state space is transformed into an isomorphic set in Fourier space. The universe of …