Engineering Commons^™

Questaal: A Package Of Electronic Structure Methods Based On The Linear Muffin-Tin Orbital Technique, Dimitar Pashov, Swagata Acharya, Walter R.L. Lambrecht, Jerome Jackson, Kirill Belashchenko, Athanasios Chantis, Francois Jamet, Mark Van Schilfgaarde

Kirill Belashchenko Publications

This paper summarises the theory and functionality behind Questaal, an open-source suite of codes for calculating the electronic structure and related properties of materials from first principles. The formalism of the linearised muffin-tin orbital (LMTO) method is revisited in detail and developed further by the introduction of short-ranged tight-binding basis functions for full-potential calculations. The LMTO method is presented in both Green's function and wave function formulations for bulk and layered systems. The suite's full-potential LMTO code uses a sophisticated basis and augmentation method that allows an efficient and precise solution to the band problem at different levels of theory, …

Program And Proceedings: Nebraska Academy Of Sciences 1880–2020, 140th Anniversary Year, One Hundred-Thirtieth Annual Meeting

Nebraska Academy of Sciences: Programs and Proceedings

No abstract provided.

Eliminating Rebar Splicing In Transverse Joints Of Precast Full Depth Bridge Deck Panels, David Gee

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

This study looks at the removal of longitudinal rebar splicing when sufficient longitudinal post-tensioning is provided for full-depth precast deck panels for simply supported bridges. Full-depth precast prestressed concrete deck panels are high quality plant produced pretensioned panels. They are often post-tensioned at the site to provide an average net compression in the joint of at least 250 psi due to effective prestress. This is to ensure adequate transfer of load as truck wheels pass over the joint. This net compression on the transverse joint is not explicitly clear by the AASHTO LRFD Bridge Design Specifications. Based on this section, …

Occurrence And Persistence Of Antibiotics Administered To Cattle In A Newly Established Feedlot, Brittany Trejo

Department of Environmental Engineering: Theses and Other Student Research

The common practice of using therapeutic antibiotics in livestock farming is a worldwide phenomenon. Over the last decade, there has been a growing concern of antibiotics entering the environment via animal manure. Similar studies have focused on the occurrence and biological effects of antibiotics in land-applied animal feedlots; however, limited research has been conducted on the occurrence and persistence of antibiotics in animal feedlots. A study was conducted to investigate the occurrence and persistence of four injected antibiotics (ceftiofur enrofloxacin, florfenicol, and tulathromycin) and two continuously fed antibiotics (monensin and tylosin) in feedlot sediment, runoff, and sediment runoff. For antibiotics …

Assessment Of An Automated Calibration Of The Sebal Algorithm To Estimate Dry-Season Surface-Energy Partitioning In A Forest–Savanna Transition In Brazil, Leonardo Laipelt, Anderson Luis Ruhoff, Ayan Santos Fleischmann, Rafael Henrique Bloedow Kayser, Elisa De Mello Kich, Humberto Ribeiro Da Rocha, Christopher Michael Usher Neale

Daugherty Water for Food Global Institute: Faculty Publications

Evapotranspiration (ET) provides a strong connection between surface energy and hydrological cycles. Advancements in remote sensing techniques have increased our understanding of energy and terrestrial water balances as well as the interaction between surface and atmosphere over large areas. In this study, we computed surface energy fluxes using the Surface Energy Balance Algorithm for Land (SEBAL) algorithm and a simplified adaptation of the CIMEC (Calibration using Inverse Modeling at Extreme Conditions) process for automated endmember selection. Our main purpose was to assess and compare the accuracy of the automated calibration of the SEBAL algorithm using two different sources of meteorological …

A Magnetic Γ-Fe2O3@Pani@Tio2 Core–Shell Nanocomposite For Arsenic Removal Via A Coupled Visible-Light-Induced Photocatalytic Oxidation– Adsorption Process†, Yuan Wang, Ping Zhang, Tian Zhang, Gang Xiang, Xinlong Wang, Simo Pehkonen, Shaojun Yuan

Department of Civil and Environmental Engineering: Faculty Publications

Arsenic polluted groundwater impairs human health and poses severe threats to drinking water supplies and ecosystems. Hence, an efficient method of simultaneous oxidation of As_(III) to As_(V), and removal of As_(V) from water has triggered increasing attention. In this study, a magnetic γ-Fe₂O₃ core–shell heterojunction nanocomposite was synthesized by means of hydrothermal crystallization of TiO₂ on the surface of the magnetic core–shell loaded with polyaniline (γ-Fe₂O₃@PANI@TiO₂). As an efficient photocatalyst coupled with adsorption, γ-Fe₂O₃@PANI@TiO₂ has a high light utilization and good …

A Wirelessly Controlled Smart Bandage With 3d-Printed Miniaturized Needle Arrays, Hossein Derakhshandeh, Fariba Aghabaglou, Alec Mccarthy, Azadeh Mostafavi, Chris Wiseman, Zack Bonick, Ian Ghanavati, Seth Harris, Craig Kreikemeier-Bower, Seyed Masoud Moosavi Basri, Jordan Rosenbohm, Ruiguo Yang, Pooria Mostafalu, Dennis Orgill, Ali Tamayol

Department of Mechanical and Materials Engineering: Faculty Publications

PUBLIC ACCESS

Communicating Computing Limitations Through Kinesthetic Pedagogy, Michael Mason

Honors Program: Senior Projects (Public)

Abstract concepts, such as those in advanced Computer Science and Mathematics, can be extremely difficult to understand fundamentally without an existing background in a similar subject. Recent research has shown that raw visualizations without learner interaction are not particularly effective at communicating complex information because they allow the learner to ignore the example (Lauer 2006, Naps 2002). Forcing somebody to interact with an example ensures that they can grasp the visualization. This paper describes a six step technique to demonstrate the limitations of computing through kinesthetic pedagogy, then offers an example exercise utilizing the method. The six proposed steps are: …

Evidence Of Arithmetical Uncertainty In Estimation Of Light And Water Use Efficiency, Meetpal S. Kukal, Suat Irmak Dr.

Department of Agricultural and Biological Systems Engineering: Faculty Publications

It was demonstrated that conventional resource use efficiency (RUE) estimation methodology is largely subject to arithmetic weakness. Extensive field research data on aboveground biomass (AGB), absorbed photosynthetically active radiation (APAR), and crop evapotranspiration (ETc) in maize, soybean, sorghum, and winter wheat confirmed this methodological bias for light use efficiency (LUE) and water use efficiency (WUE) estimation. LUE and WUE were derived using cumulated (data aggregates across samplings) and independent (data increments across samplings) approaches. Use of cumulated data yielded strong-but-false correlation between AGB and APAR or Etc, being a statistical artefact. RUE values from an independent (data increments across samplings) …

Low Latency Bearing Fault Detection Of Direct-Drive Wind Turbines Using Stator Current, Samrat Nath, Jingxian Wu, Yue Zhao, Wei Qiao

Department of Electrical and Computer Engineering: Faculty Publications

Low latency change detection aims to minimize the detection delay of an abrupt change in probability distributions of a random process, subject to certain performance constraints such as the probability of false alarm (PFA). In this paper, we study the low latency detection of bearing faults of direct-drive wind turbines (WT), by analyzing the statistical behaviors of stator currents generated by the WT in real-time. It is discovered that the presence of fault will affect the statistical distribution of WT stator current amplitude at certain frequencies. Since the signature of a fault can appear in one of the multiple possible …

Predicting Escherichia Coli Loads In Cascading Dams With Machine Learning: An Integration Of Hydrometeorology, Animal Density And Grazing Pattern, Olufemi P. Abimbola, Aaron R. Mittelstet, Tiffany Messer, Elaine D. Berry, Shannon L. Bartelt-Hunt, Samuel Hansen

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Accurate prediction of Escherichia coli contamination in surface waters is challenging due to considerable uncertainty in the physical, chemical and biological variables that control E. coli occurrence and sources in surface waters. This study proposes a novel approach by integrating hydro-climatic variables as well as animal density and grazing pattern in the feature selection modeling phase to increase E. coli prediction accuracy for two cascading dams at the USMeat Animal Research Center (USMARC), Nebraska. Predictive models were developed using regression techniques and an artificial neural network (ANN). Two adaptive neuro-fuzzy inference system (ANFIS) structures including subtractive clustering and fuzzy c-means …

Geometric Iteration Of A Knee Prosthetic And Static Stress-Bearing Capacity, Alexander Wheeler

Honors Program: Senior Projects (Public)

The purpose of this study was to improve a prosthetic knee model in terms of size, weight, and biocompatibility. Several tests were run to determine its effectiveness in supporting static and quasistatic loads. The positions in which these tests were run include static upright standing, static one-knee 90 degree kneeling, static squatting at maximum flexion, and quasistatic midstride. These simulations were conducted to find areas of high stress and strain. These patterns were used to determine the maximum body weight a physical prosthetic could support. The material used to create the prosthetic was changed from AISI 316 stainless steel to …

Innovation In Pedagogy And Technology Symposium, 2019: Selected Conference Proceedings, University Of Nebraska Online, University Of Nebraska Information Technology Services

Zea E-Books Collection

Advancing Technology in Education at the University of Nebraska, May 7, 2019

Welcome Address • Susan Fritz, Ph.D., Executive Vice President and Provost, University of Nebraska 6

Opening Remarks • Mary Niemiec, Associate Vice President for Digital Education, Director of University of Nebraska Online 6

Keynote Presentation: Shaping the Next Generation of Higher Education • Bryan Alexander, Ph.D. 6

Featured Extended Presentation: Redesigning Courses & Determining Effectiveness Through Research • Tanya Joosten, University of Wisconsin-Milwaukee (UWM), Erin Blankenship, Ph.D. (UNL), Ella Burnham (UNL), Nate Eidem, Ph.D. (UNK), Marnie Imhoff (UNMC), Linsey Donner (UNMC), Ellie Miller (UNMC) 7

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Improvement Of Low Traffic Volume Gravel Roads In Nebraska, Richard L. Wood, Yong-Rak Kim, Yijun Liao, Mohammad E. Mohammadi

Nebraska Department of Transportation: Research Reports

In the state of Nebraska, over one-third of roadways are unpaved, and consequently require a significant amount of financial and operational resources to maintain their operation. Undesired behavior of surface gravel aggregates and the road surfaces can include rutting, corrugation, and ponding that may lead to reduced driving safety, speed or network efficiency, and fuel economy. This study evaluates the parameters that characterize the performance and condition of gravel roads overtime period related to various aggregate mix designs. The parameters, including width, slope, and crown profiles, are examples of performance criteria. As remote sensing technologies have advanced in the recent …

Synthesis Of Repair Practices Of Damaged Precast/Prestressed Concrete Girders, George Morcous, Richard L. Wood, Antony Mohsen Kamal Masoud Kodsy

Nebraska Department of Transportation: Research Reports

Bridge girders are constantly subjected to various types of damage during their service life. There is currently limited knowledge or guidelines provided by the NDOT Bridge Office Policies and Procedures (BOPP) regarding the assessment and repair procedures of damaged precast/prestressed concrete girders. This report aims to develop a comprehensive repair manual for precast/prestressed concrete girders subjected to damage caused by over-height vehicular collision and damage located at the girder ends. Over-height vehicular collision damage typically occurs at the middle portion of the exterior girders and the primary concerns are focused on flexural deficiencies. Girder end damage can occur due to …

Infrared-Active Phonon Modes In Single-Crystal Thorium Dioxide And Uranium Dioxide, Sean Knight, Rafal Korlacki, Christina Dugan, James C. Petrosky, Alyssa Lynn Mock, Peter A. Dowben, J. Matthew Mann, Martin M. Kimani, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

The infrared-active phonon modes, in single-crystal samples of thorium dioxide (ThO₂) and uranium dioxide (UO₂), were investigated using spectroscopic ellipsometry and compared with density functional theory. Both ThO₂ and UO₂ are found to have one infrared-active phonon mode pair [consisting of one transverse optic (TO) and one associated longitudinal optic (LO) mode], which is responsible for the dominant features in the ellipsometric data. At room temperature, our results for the mode pair’s resonant frequencies and broadening parameters are comparable with previous reflectance spectroscopy characterizations and density functional theory predictions. For ThO₂, our …

Banning Carbon Nanotubes Would Be Scientifically Unjustified And Damaging To Innovation, Daniel A. Heller, Prakrit V. Jena, Matteo Pasquali, Kostas Kostarelos, Lucia G. Delogu, Rachel E. Meidl, Slava V. Rotkin, David A. Scheinberg, Robert E. Schwartz, Mauricio Terrones, Yu Huang Wang, Alberto Bianco, Ardemis A. Boghossian, Sofie Cambré, Laurent Cognet, Simon R. Corrie, Philip Demokritou, Silvia Giordani, Tobias Hertel, Tetyana Ignatova, Mohammad F. Islam, Nicole M. Iverson, Anand Jagota, Dawid Janas, Junichiro Kono, Sebastian Kruss, Markita P. Landry, Yan Li, Richard Martel, Shigeo Maruyama, Anton V. Naumov, Maurizio Prato, Susan J. Quinn, Daniel Roxbury, Michael S. Strano, James M. Tour, R. Bruce Weisman, Wim Wenseleers, Masako Yudasaka

Department of Agricultural and Biological Systems Engineering: Faculty Publications

In a recent correspondence, the Swedish non-profit organization ChemSec announced the addition of carbon nanotubes to the SIN (‘Substitute It Now’) list1. Carbon nanotubes were added as an entire material class that “should be restricted or banned in the EU.” We believe that this recommendation confuses researchers and the public as it is based on evidence from a very narrow subset of data. Such a designation will likely hinder innovations that could lead to safe and effective applications of carbon nanotubes. Furthermore, this line of reasoning could damage other fields of science and technology, if applied similarly. We have worked …

Scalable Universal Space Vector Pulse Width Modulation Scheme For Multilevel Inverters, Wei Qiao, Fa Chen, Liyan Qu

Department of Electrical and Computer Engineering: Faculty Publications

A scalable universal space vector pulse-width modulation (SVPWM) scheme for multilevel inverters is disclosed. In the disclosed SVPWM scheme, the modulation triable is quickly identified based on a coordinate transformation from an α-β coordinate system to a 120^o oblique coordinate system. Then, the duty cycles and switching states of the three vertices of the modulation triangle are determined by simple algebraic computations. In a switching period, any vertex of the modulation triangle can be flexibly selected as the start point to optimize the switching sequence with flexibly adjustable duty cycle(s) for the redundant switching state(s) according to specific applications.

Effects Of Intrinsic Defects And Alloying With Fe On The Half-Metallicity Of Co2Mnsi, G. G. Baez Flores, Ivan A. Zhuravlev, Kirill Belashchenko

Kirill Belashchenko Publications

The electronic structure and half-metallic gap of Co2MnSi in the presence of crystallographic defects, partial Fe substitution for Mn, and thermal spin fluctuations are studied using the coherent potential approximation and the disordered local moment method. In the presence of 5% Co or Mn vacancies the Fermi level shifts down to the minority-spin valence-band maximum. In contrast to NiMnSb, both types of Mn antisite defects in Co2MnSi are strongly exchange coupled to the host magnetization, and thermal spin fluctuations do not strongly affect the half-metallic gap. Partial substitution of Mn by Fe results in considerable changes in the Bloch spectral …

Anomalous Eutectic Microstructures In Mg–Al Structural Alloy Prepared By Rapid Solidification, Soodabeh Azadehranjbar, Jian Wang, Jeffrey E. Shield

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Magnesium is the lightest engineering metal 1 However, conventional Mg alloys typically suffer from low strength and poor deformability due to very few slip systems and easy twinning 3 Alloying Mg with other materials and microstructural engineering are promising approaches to increase ductility and strength of Mg In the current work, non equilibrium solidification conditions were applied to induce a transition from regular to anomalous eutectic in Mg Al eutectic alloy such that four distinguished microstructures were acquired and the corresponding formation mechanisms were investigated

Risk And Cost Assessment Of Nitrate Contamination In Domestic Wells, Pongpun Juntakut, Erin M.K. Haacker, Daniel D. Snow, Chittaranjan Ray

Daugherty Water for Food Global Institute: Faculty Publications

This study combines empirical predictive and economics models to estimate the cost of remediation for domestic wells exceeding suggested treatment thresholds for nitrates. A multiple logistic regression model predicted the probability of well contamination by nitrate, and a life cycle costing methodology was used to estimate costs of nitrate contamination in groundwater in two areas of Nebraska. In south-central Nebraska, 37% of wells were estimated to be at risk of exceeding a threshold of 7.5 mg/L as N, and 17% were at risk of exceeding 10 mg/L as N, the legal limit for human consumption in the United States. In …

Algorithms Of Oppression [Uno Pa Theory Proseminar Presentation], Sue Ann Gardner

University of Nebraska-Lincoln Libraries: Presentations

Slides of two classes taught in the Theory Proseminar in the School of Public Administration at the University of Nebraska at Omaha by Sue Ann Gardner on February 11 and 18, 2020.

Connects information theory to applicable knowledge frameworks in public administration. Includes an in-depth discussion of the concepts addressed in Samiya Umoja Noble's book Algorithms of Oppression (published by New York University Press, New York, New York, United States, 2018) in the context of public administration and public academic libraries.

Integration Of Sodium Hypochlorite Pretreatment With Co-Immobilized Microalgae/Bacteria Treatment Of Meat Processing Wastewater, Xinjuan Hu, Yulie Meneses, Ashraf Aly Hassan

Department of Food Science and Technology: Faculty Publications

Wastewater with 0.2, 0.4, 0.8, 1.0 mg/L free chlorine was biologically treated using co-immobilized microalgae/ bacteria. In contrast, non-pretreated wastewater was treated with beads (control) and blank beads (blank) under the same operating condition. Results showed that NaClO pretreatment removed 8–33% total nitrogen (TN), 31–45% true color and 0.7–2.5 log CFU/mL aerobic-bacteria. At the end of treatment, maximum algal biomass (2,027 dry weight mg/L) was achieved with 0.2 mg/L free chlorine. Bacterial growth in wastewater was decreased by NaClO pretreatment before reaching 7.2–7.7 log CFU/mL on the fifth day. Beads with microorganisms (control) removed 15% more chemical-oxygen-demand (COD), 16% more …

Cycle-To-Cycle Flow Variations In A Square Duct With A Symmetrically Oscillating Constriction, Erica Sherman, Lori M. Lambert, Bethany White, Michael H. Krane, Timothy Wei

Department of Mechanical and Materials Engineering: Faculty Publications

Spatially and temporally resolved Digital Particle Image Velocimetry (DPIV) measurements are presented of flow complexities in a nominally two-dimensional, symmetric, duct with an oscillating constriction. The motivation for this research lies in advancing the state-of-the-art in applying integral control volume analysis to modeling unsteady internal flows. The specific target is acoustic modeling of human phonation. The integral mass and momentum equations are directly coupled to the acoustic equations and provide quantitative insight into acoustic source strengths in addition to the dynamics of the fluid-structure interactions in the glottis. In this study, a square cross-section duct was constructed with symmetric, computer …

Early Detection Of Near-Surface Void Defects In Concrete Pavement Using Drone Based Thermography And Gpr Methods, Zhigang Shen, Ece Erdogmus, George Morcous, Chngsheng Cheng, Zhexiong Shang, Theresa Mccabe, Antony Mohsen Kamal Masoud Kodsy

Nebraska Department of Transportation: Research Reports

The goal of this research is to evaluate the feasibility and the performance of using UAV-mounted infrared thermography (IRT) and ground penetration radar (GPR) to detect sub-surface voids caused by consolidation issues in concrete pavement. The motivation of the study is to identify the consolidation defects as early as the initial set of concrete to avoid having this problem in large pavement sections, which is costly and time consuming to repair. Using the two technologies in combination to detect subsurface voids in the concrete initial set stage is new and aims to take advantage of the strengths and minimize the …

Nitrate Removal From Groundwater Using Immobilized Heterotrophic Algae, Sara Mollamohammada, Ashraf Aly Hassan, Mohamed Dahab

Department of Civil and Environmental Engineering: Faculty Publications

The treatment efficiency of Chlorella sorokiniana and Scenedesmus species, immobilized in sodium alginate, was evaluated for removing nitrate from groundwater. The experiments were performed initially in batch mode and the best-performing conditions were replicated in sequencing batch reactor mode. S. sp. showed a higher nitrate uptake in short term than C. sorokiniana. Immobilized S. sp. and C. sorokiniana cells showed 90% nitrate removal in 9 and 12 days, respectively. The optimal ratio of algal beads/water was found to be 12.5% (v:v). Comparatively, suspended S. sp. cells were able to remove only up to 35% of nitrate in 8 …

Arjen Y. Hoekstra 1967–2019, Davy Vanham, Mesfin Mekonnen, Ashok K. Chapagain

Daugherty Water for Food Global Institute: Faculty Publications

Arjen Hoekstra introduced the water footprint in 20021, building on the concept of virtual water Tony Allan to discuss the role of trade in alleviating water scarcity in the Middle East. He thereby opened a new dimension in the debate around fair and sustainable allocation of freshwater resources. He laid the foundations to show the role of indirect water (that is, water used elsewhere to produce goods we consume) in our daily life beyond our direct use for drinking, cooking or washing. The water footprint is an indicator of direct and indirect water use by a producer or consumer, showing …

Swine Slurry Characteristics As Affected By Selected Additives And Disinfectants, Jon Duerschner, Shannon L. Bartelt-Hunt, Kent Eskridge, John E. Gilley, Xu Li, Amy M. Schmidt, Daniel D. Snow

Nebraska Water Center: Faculty Publications

Current swine industry practice is to house animals in confinement facilities which capture and store feces and urine as slurry in pits below the production area. Additives and disinfectants may be introduced into the manure pits. This study was conducted to measure the effects of additives and disinfectants on temporal changes in swine slurry characteristics. Slurry from a commercial swine production facility in southeast Nebraska, USA was collected and transferred to 57 L reactors located within a greenhouse. Selected additives and disinfectants were added to the reactors and physical properties, chemical characteristics, and antibiotic concentrations were monitored for 40 days. …

Optfill: A Tool For Infeasible Cycle-Free Gapfilling Of Stoichiometric Metabolic Models, Wheaton L. Schroeder, Rajib Saha

Mid-America Transportation Center: Final Reports and Technical Briefs

Stoichiometric metabolic modeling, particularly genome-scale models (GSMs), is now an indispens- able tool for systems biology. The model reconstruction process typically involves collecting informa- tion from public databases; however, incomplete systems knowledge leaves gaps in any reconstruc- tion. Current tools for addressing gaps use databases of biochemical functionalities to address gaps on a per-metabolite basis and can provide multiple solutions but cannot avoid thermodynami- cally infeasible cycles (TICs), invariably requiring lengthy manual curation. To address these limita- tions, this work introduces an optimization-based multi-step method named OptFill, which performs TIC-avoiding whole-model gapfilling. We applied OptFill to three fictional prokaryotic models …

Effects Of Surface Heterogeneity Due To Drip Irrigation On Scintillometer Estimates Of Sensible, Latent Heat Fluxes And Evapotranspiration Over Vineyards, Hatim M. E. Geli, José González-Piqueras, Christopher M. U. Neale, Claudio Balbontín, Isidro Campos, Alfonso Calera

Daugherty Water for Food Global Institute: Faculty Publications

Accurate estimates of sensible (H) and latent (LE) heat fluxes and actual evapotranspiration (ET) are required for monitoring vegetation growth and improved agricultural water management. A large aperture scintillometer (LAS) was used to provide these estimates with the objective of quantifying the effects of surface heterogeneity due to soil moisture and vegetation growth variability. The study was conducted over drip-irrigated vineyards located in a semi-arid region in Albacete, Spain during summer 2007. Surface heterogeneity was characterized by integrating eddy covariance (EC) observations of H, LE and ET; land surface temperature (LST) and normalized difference vegetation index (NDVI) data from Landsat …