Engineering Commons^™

Framework For Extracting And Characterizing Load Profile Variability Based On A Comparative Study Of Different Wavelet Functions, Andrew Parker, Kevin James, Dongming Peng, Mahmoud Alahmad

Durham School of Architectural Engineering and Construction: Faculty Publications

The penetration of distributed energy resources (DERs) on the electric power system is changing traditional power flow and analysis studies. DERs may cause the systems' protection and control equipment to operate outside their intended parameters, due to DERs' variability and dispatchability. As this penetration grows, hosting capacity studies as well as protection and control impact mitigation become critical components to advance this penetration. In order to conduct such studies accurately, the electric power system's distribution components should be modeled correctly, and will require realistic time series loads at varying temporal and spatial conditions. The load component consists of the built …

Representational Learning Approach For Predicting Developer Expertise Using Eye Movements, Sumeet Maan

School of Computing: Dissertations, Theses, and Student Research

The thesis analyzes an existing eye-tracking dataset collected while software developers were solving bug fixing tasks in an open-source system. The analysis is performed using a representational learning approach namely, Multi-layer Perceptron (MLP). The novel aspect of the analysis is the introduction of a new feature engineering method based on the eye-tracking data. This is then used to predict developer expertise on the data. The dataset used in this thesis is inherently more complex because it is collected in a very dynamic environment i.e., the Eclipse IDE using an eye-tracking plugin, iTrace. Previous work in this area only worked on …

Bayes’ Network And Smart Sensors: Occupancy Detection, Donald Tryon

Department of Construction Engineering and Management: Dissertations, Theses, and Student Research

This dissertation presents a Bayesian analysis for determining residential occupancy using inexpensive commercially available passive infrared (PIR) motion detectors, compared against two other detectors that were used to establish ground-truth. One of the ground-truth detectors was a GPS signal from a smartphone, the second was a Bluetooth key fob. Data were gathered from four residential locations, and then analyzed to determine occupancy. The occupancy data collected from the PIR sensors were compared against ground-truth to verify the results of the PIR sensor events that were collected every minute for a week. The Bayesian training data that was used to determine …

Fluid Modeling And Analysis Of A Mash Tl-6 Vehicle Model, Elisa Vasquez

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

The objective of this research project was to replicate the dynamic behavior of a truck-tank trailer combination vehicle using representative dimensions, properties, and inertias of the trailer/fluid ballast combination. A literature review was completed describing techniques for modeling fluids and fluid-container interactions using finite element analysis. Various fluid modeling techniques were identified, and parameters associated with those models were archived. Next, researchers utilized the tank geometry of the elliptical straight-frame 5949 trailer produced by LBT Inc. to generate a finite element mesh using finite element analysis preprocessors HyperMesh and LS PrePost. Material properties were taken from reference guides, research papers, …

Preparing For A Driverless Future, Daniel P. Piatkowski, Santosh Pitla, Joe Luck, Josephine K. Hazelton

Nebraska Department of Transportation: Research Reports

Autonomous vehicles (AVs) are widely considered to be the future of surface transportation in the United States, but little is understood about how people will interact with these vehicles, what they will use them for, and how they will impact our roads. However, farmers have been interacting with some degree of AV technology, primarily auto-guidance, in Nebraska for at least the last 10 years. The research in Section 1 first utilizes in-depth qualitative interviews to understand farmers’ experiences with using highly automated technology in order to inform adoption and diffusion patterns of AVs. The findings in Section 1 lead to …

Investing In Bicycle Infrastructure To Spur Statewide Economic Growth Through Bicycle Tourism, Pedro Aguero Arroyo, Daniel P. Piatkowski, F. Alsaleem

Nebraska Department of Transportation: Research Reports

Bicycle tourism is a growing industry that has been shown by prior studies to contribute significantly to the economy of numerous states. The economic benefits of recreational bicycling are not limited to the direct effects of the transactions of bicyclists in related industries, but also spillover effects such as the reduction of automobile activity and its associated costs to society, or the decrease of the costs of obesity and inactivity to the healthcare system. This study focuses on the former and provides a qualitative and quantitative analysis of the economic impacts derived from recreational bicycling expenditure, as well as an …

A Big Data Approach For Improving Nebraska Cycling Routes, Fadi Alsaleem, Ali Al-Ramini, Mohammad Ali Takallou, Daniel P. Piatkowski

Nebraska Department of Transportation: Research Reports

More people are becoming interested in creating healthy lifestyle habits for themselves. It has been proved that cycling has several health benefits. Therefore, governments are planning towards more cycling-friendly infrastructures and environments. To understand the cycling activities in Nebraska, we analyze Strava data for the last three years, providing valuable insight into cycling activities for urban planning purposes.

We analyze commute and recreational cycling patterns varying between weekdays and weekends to identify peak hours. Moreover, we study the effect of weather on cycling activity patterns for the last three years. Also, we use the impact of the outside temperature as …

Utilizing Kryton Kim Technology In Bridge Deck And Rail Construction To Protect Against Chloride Ion Penetration, Mick Syslo, Wally Heyen, Lieska Halsey, David Hansen, Tim Kranson

Nebraska Department of Transportation: Research Reports

No abstract provided.

Best Practices To Address Issues Of Excess Aggregate Dust In Nebraska, Jiong Hu, Yong-Rak Kim, Temirlan Barissov, Shaya Gholami, Julia Grasley

Nebraska Department of Transportation: Research Reports

The negative impacts of an excessive amount of dust on concrete performance have been known and reported in different states. The extent and impact of dust on concrete performance, which depends not only on quantity but also on the nature of dust could be complicated. For example, clay coatings showed a more harmful impact on concrete performance compared with carbonates (limestone dust) or stone dust. While clays that weakly adhere to aggregate will be dispersed in the mixing water and could lead to the workability or air entrainment issues, clays that are strongly bonded to the aggregate surface will remain …

Quantification Of Nitric Oxide Via Single-Walled Carbon Nanotubes, Jakob Meier

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

Nitric oxide (NO), a free radical present in biological systems, can have many beneficial and detrimental effects on the body. Due to NO’s short half-life, its detection and quantification is difficult. This inability to quantify NO has hindered researchers that are trying to understand NO’s impact in healthy and diseased conditions. Single-walled carbon nanotubes (SWNT), can become selective to various analytes when wrapped in specific single-stranded DNA strands. The presence of the analyte of interest can change the wavelength and/or intensity of the SWNT’s fluorescence, allowing the SWNT to be used as a sensor. One type of SWNT sensor, 6,5 …

Ultrafast Spin-Currents And Charge Conversion At 3d-5d Interfaces Probed By Time-Domain Terahertz Spectroscopy, T. H. Dang, J. Hawecker, E. Rongione, G. Baez Flores, D. Q. To, J. C. Rojas-Sanchez, H. Nong, J. Mangeney, J. Tignon, F. Godel, S. Collin, P. Seneor, M. Bibes, A. Fert, M. Anane, J. M. George, L. Vila, M. Cosset-Cheneau, D. Dolfi, R. Lebrun, P. Bortolotti, Kirill Belashchenko, S. Dhillon, H. Jaffrès

Kirill Belashchenko Publications

Spintronic structures are extensively investigated for their spin-orbit torque properties, required for magnetic commutation functionalities. Current progress in these materials is dependent on the interface engineering for the optimization of spin transmission. Here, we advance the analysis of ultrafast spin-charge conversion phenomena at ferromagnetic-Transition metal interfaces due to their inverse spin-Hall effect properties. In particular, the intrinsic inverse spin-Hall effect of Pt-based systems and extrinsic inverse spin-Hall effect of Au:W and Au:Ta in NiFe/Au:(W,Ta) bilayers are investigated. The spin-charge conversion is probed by complementary techniques-ultrafast THz time-domain spectroscopy in the dynamic regime for THz pulse emission and ferromagnetic resonance spin-pumping …

Concentration And Treatment Of Odors Generated By Landfills, Gabriel Cohen

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

Landfills produce hydrogen sulfide (H₂S), an odorous compound that can be a nuisance and danger to public. Biological treatment, in particular bio-trickling filters, is a method for controlling H₂S emissions but startup costs can be costly. The goal of this study is to provide a low-cost method for improving environmental air quality in Nebraska through an odor control device. This study determined that the Loup Central Landfill located near Elba, NE would be an adequate site for the testing and implementation of the odor control device. The off-gas of the Loup Central Landfill was tested for …

Neonicotinoid Pesticide And Nitrate Removal In Floating Treatment Wetlands, Julia Lindgren

Department of Environmental Engineering: Theses and Other Student Research

Nutrient and pesticide concentrations in surface water are a growing concern in the Midwest. Floating treatment wetlands (FTWs) are often used to remove excess nutrients from surface water and should be considered for removal of emerging contaminants, such as neonicotinoids. Therefore, the objectives for this research project were: 1) Determine FTW neonicotinoid removal capacity, 2) Quantify neonicotinoid incorporation into floating macrophytes, and 3) Explore potential implications of neonicotinoids on microbial denitrification. A microcosm and mesocosm experiment was completed. The mesocosm experiment evaluated 3 treatments: 1) FTW mesocosm with neonicotinoids, 2) FTW without neonicotinoids, and 3) mesocosm with neonicotinoids and without …

Toward Understanding Underlying Mechanisms Of Drag Reduction In Turbulent Flow Control, Alex Rogge

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

The underlying mechanisms of three different flow-control strategies on drag reduction in a turbulent channel flow are investigated by direct numerical simulations. These strategies include the addition of a small concentration of long-chain polymers into a fluid, the incorporation of slip surfaces, and the application of an external body force. While it has been believed that such methods lead to a skin-friction reduction by controlling near-wall flow structures, the underlying mechanisms at play are still not as clear. In this study, a temporal analysis is employed to elucidate underlying drag-reduction mechanisms among these methods. The analysis is based on the …

Sustainable Drug Release From Polycaprolactone Coated Chitin‑Lignin Gel Fibrous Scaffolds, Turdimuhammad Abdullah, Kalamegam Gauthaman, Azadeh Mostafavi, Ahmed Alshahrie, Numan Salah, Pierfrancesco Morganti, Angelo Chianese, Ali Tamayol, Adnan Memic

Department of Mechanical and Materials Engineering: Faculty Publications

Non-healing wounds have placed an enormous stress on both patients and healthcare systems worldwide. Severe complications induced by these wounds can lead to limb amputation or even death and urgently require more effective treatments. Electrospun scaffolds have great potential for improving wound healing treatments by providing controlled drug delivery. Previously, we developed fibrous scaffolds from complex carbohydrate polymers [i.e. chitin-lignin (CL) gels]. However, their application was limited by solubility and undesirable burst drug release. Here, a coaxial electrospinning is applied to encapsulate the CL gels with polycaprolactone (PCL). Presence of a PCL shell layer thus provides longer shelf-life for the …

Risk Of Injury Analysis In Depth Jump And Squat Jump, Curtis L. Tomasevicz, Jeffrey C. Woldstad, [email protected]

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Introduction: The depth jump (DJ) and squat jump (SJ) are accepted ways to assess and train power producing ability but are not without risk of injury. Methods: Sixteen male participants (age = 21.7 ± 1.54 yrs., height = 177.7 ± 11.4 cm, mass = 77.7 ± 13.6 kg) were evaluated for power exertion capabilities while being assessed for risk of injury in the knee and low back through a range of resistances based on a percentage of participants’ heights in the DJ (0% through 50%) and bodyweights for the SJ (0% through 100%). Two variables were used to assess the …

Comparative Analyses Of Variable And Fixed Rate Irrigation And Nitrogen Management For Maize In Different Soil Types: Part I. Impact On Soil-Water Dynamics And Crop Evapotranspiration, Vasudha Sharma, Suat Irmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Understanding the soil-water dynamics and maize evapotranspiration (ETc) under variable rate irrigation (VRI) and variable rate fertigation (VRF) management with respect to soil spatial variability constitutes the basis for developing effective variable rate water and nitrogen management strategies. This long-term research was designed to quantify and compare the soil-water dynamics, including available water (AW), and ETc during vegetative and reproductive growth periods of VRI, fixed rate irrigation (FRI) and no-irrigation (NI) under fixed rate fertigation (FRF), VRF and pre-plant (PP) nitrogen management in three different soil types [Crete silt loam (S1); Hastings silty clay loam (S2) and Hastings silt loam …

Machine Learning Augmentation Micro-Sensors For Smart Device Applications, Mohammad H. Hasan

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

Novel smart technologies such as wearable devices and unconventional robotics have been enabled by advancements in semiconductor technologies, which have miniaturized the sizes of transistors and sensors. These technologies promise great improvements to public health. However, current computational paradigms are ill-suited for use in novel smart technologies as they fail to meet their strict power and size requirements. In this dissertation, we present two bio-inspired colocalized sensing-and-computing schemes performed at the sensor level: continuous-time recurrent neural networks (CTRNNs) and reservoir computers (RCs). These schemes arise from the nonlinear dynamics of micro-electro-mechanical systems (MEMS), which facilitates computing, and the inherent ability …

Proximity-Induced Magnetization In Graphene: Towards Efficient Spin Gating, Mihovil Bosnar, Ivor Lončarić, P. Lazić, Kirill Belashchenko, Igor Žutić

Kirill Belashchenko Publications

Gate-tunable spin-dependent properties could be induced in graphene at room temperature through the magnetic proximity effect by placing it in contact with a metallic ferromagnet. Because strong chemical bonding with the metallic substrate makes gating ineffective, an intervening passivation layer is needed. Previously considered passivation layers result in a large shift of the Dirac point away from the Fermi level, so that unrealistically large gate fields are required to tune the spin polarization in graphene (Gr). We show that a monolayer of Au or Pt used as the passivation layer between Co and graphene brings the Dirac point closer to …

Strain And Stress Relationships For Optical Phonon Modes In Monoclinic Crystals With Β-Ga2O3 As An Example, Rafal Korlacki, Megan Stokey, A. Mock, Sean Knight, A. Papamichail, V. Darakchieva, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

Strain-stress relationships for physical properties are of interest for heteroepitaxial material systems, where strain and stress are inherent due to thermal expansion and lattice mismatch. We report linear perturbation theory strain and stress relationships for optical phonon modes in monoclinic crystals for strain and stress situations which maintain the monoclinic symmetry of the crystal. By using symmetry group analysis and phonon frequencies obtained under various deformation scenarios from density-functional perturbation theory calculations on β-Ga₂O₃, we obtain four strain and four stress potential parameters for each phonon mode. We demonstrate that these parameters are sufficient to …

Strain And Stress Relationships For Optical Phonon Modes In Monoclinic Crystals With Β-Ga2O3 As An Example, Rafal Korlacki, Megan Stokey, A. Mock, Sean Knight, Alexis Papamichail, Vanya Darakchieva, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

Strain-stress relationships for physical properties are of interest for heteroepitaxial material systems, where strain and stress are inherent due to thermal expansion and lattice mismatch. We report linear perturbation theory strain and stress relationships for optical phonon modes in monoclinic crystals for strain and stress situations which maintain the monoclinic symmetry of the crystal. By using symmetry group analysis and phonon frequencies obtained under various deformation scenarios from density-functional perturbation theory calculations on β-Ga₂O₃, we obtain four strain and four stress potential parameters for each phonon mode. We demonstrate that these parameters are sufficient to …

Effective Hair Styling Compositions And Processes, Yiqi Yang, Helan Xu, Kaili Song

Department of Textiles, Merchandising and Fashion Design: Faculty Publications

This disclosure relates to hair styling compositions and processes , and more particularly to compositions for disentangling or crosslinking hair that are useful in hair styling processes.

Formal Concept Analysis Applications In Bioinformatics, Sarah Roscoe

School of Computing: Dissertations, Theses, and Student Research

Bioinformatics is an important field that seeks to solve biological problems with the help of computation. One specific field in bioinformatics is that of genomics, the study of genes and their functions. Genomics can provide valuable analysis as to the interaction between how genes interact with their environment. One such way to measure the interaction is through gene expression data, which determines whether (and how much) a certain gene activates in a situation. Analyzing this data can be critical for predicting diseases or other biological reactions. One method used for analysis is Formal Concept Analysis (FCA), a computing technique based …

Detection Of Uncompensated Magnetization At The Interface Of An Epitaxial Antiferromagnetic Insulator, Pavel N. Lapa, Min Han Lee, Igor V. Roshchin, Kirill Belashchenko, Ivan K. Schuller

Kirill Belashchenko Publications

We have probed directly the temperature and magnetic field dependence of pinned uncompensated magnetization at the interface of antiferromagnetic FeF₂ with Cu, using FeF₂-Cu-Co spin valves. Electrons polarized by the Co layer are scattered by the pinned uncompensated moments at the FeF₂-Cu interface giving rise to giant magnetoresistance. We determined the direction and magnitude of the pinned uncompensated magnetization at different magnetic fields and temperatures using the angular dependencies of resistance. The strong FeF₂ anisotropy pins the uncompensated magnetization along the easy axis independent of the cooling field orientation. Most interestingly, magnetic fields as …

Leveraging Abet Accreditation To Promote Inclusion Of Noise Control Engineering Concepts In Engineering Programs, Lily M. Wang, Bryan Beamer

Durham School of Architectural Engineering and Construction: Faculty Publications

Accreditation Board for Engineering and Technology, Inc. (ABET) accreditation is an internationally recognized system ensuring consistency and quality in engineering education programs. As a part of ABET accreditation, there is no set requirement for any general engineering program to include noise control engineering concepts in their curricula. However, one of the seven student outcomes that each ABET accredited engineering program must document is their students’ “ability to apply engineering design to produce solutions that meet specified needs with consideration of public health, safety, and welfare…” Controlling noise in the authors’ view is a fundamental strategy for protecting workers from occupational …

Strain And Stress Relationships For Optical Phonon Modes In Monoclinic Crystals With Β-Ga2O3 As An Example, Rafal Korlacki, Megan Stokey, Alyssa Lynn Mock, Sean Knight, Alexis Papamichail, Vanya Darakchieva, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

Strain-stress relationships for physical properties are of interest for heteroepitaxial material systems, where strain and stress are inherent due to thermal expansion and lattice mismatch. We report linear perturbation theory strain and stress relationships for optical phonon modes in monoclinic crystals for strain and stress situations which maintain the monoclinic symmetry of the crystal. By using symmetry group analysis and phonon frequencies obtained under various deformation scenarios from density-functional perturbation theory calculations on β-Ga₂O₃, we obtain four strain and four stress potential parameters for each phonon mode. We demonstrate that these parameters are sufficient to …

Reinvestigation Of The Intrinsic Magnetic Properties Of (Fe1-Xcox)2b Alloys And Crystallization Behavior Of Ribbons, Tej Nath Lamichhane, Olena Palasyuk, Vladimir P. Antropov, Ivan A. Zhuravlev, Kirill Belashchenko, Ikenna C. Nlebedim, Kevin W. Dennis, Anton Jesche, Matthew J. Kramer, Sergey L. Bud'ko, R. William Mccallum, Paul C. Canfield, Valentin Taufour

Kirill Belashchenko Publications

New determination of the magnetic anisotropy from single crystals of (Fe_1-xCo_x)2B alloys are presented. The anomalous temperature dependence of the anisotropy constant is discussed using the standard Callen-Callen theory, which is shown to be insufficient to explain the experimental results. A more material specific study using first-principles calculations with disordered moments approach gives a much more consistent interpretation of the experimental data. Since the intrinsic properties of the alloys with x=0.3-0.35 are promising for permanent magnets applications, initial investigation of the extrinsic properties are described, in particular the crystallization of melt spun ribbons with Cu, Al, …

Designing A Week-Long Biomedical Engineering Summer Camp To Increase Young Students’ Interest And Self-Efficacy In Stem, Kayla Ney

Honors Program: Senior Projects (Public)

In order to combat the negative feelings many young students have towards STEM, I designed a week-long summer camp that teaches students about biomedical engineering as well as collaboration, communication, and confidence with STEM subjects. This work includes a literature review outlining what STEM is and current issues in STEM education, including disinterest in STEM and attrition in STEM degree programs. The literature review outlines current methods and ideas being utilized to combat these issues, namely, inclusive pedagogical strategies, and how some of these concepts can be applied to the summer camp. The curriculum document included outlines each activity, its …

Optimal Control Of Active Nematics, Michael M. Norton, Piyush Grover, Michael F. Hagan, Seth Fraden

Department of Mechanical and Materials Engineering: Faculty Publications

In this work we present the first systematic framework to sculpt active nematic systems, using optimal control theory and a hydrodynamic model of active nematics. We demonstrate the use of two different control fields, (i) applied vorticity and (ii) activity strength, to shape the dynamics of an extensile active nematic that is confined to a disk. In the absence of control inputs, the system exhibits two attractors, clockwise and counterclockwise circulating states characterized by two co-rotating topological þ1 2 defects. We specifically seek spatiotemporal inputs that switch the system from one attractor to the other; we also examine phase-shifting perturbations. …

Satellite-Based Monitoring Of Irrigation Water Use: Assessing Measurement Errors And Their Implications For Agricultural Water Management Policy, T. Foster, Taro Mieno, Nicholas Brozovic

Daugherty Water for Food Global Institute: Faculty Publications

Reliable accounting of agricultural water use is critical for sustainable water management. However, the majority of agricultural water use is not monitored, with limited metering of irrigation despite increasing pressure on both groundwater and surface water resources in many agricultural regions worldwide. Satellite remote sensing has been proposed as a low-cost and scalable solution to fill widespread gaps in monitoring of irrigation water use in both developed and developing countries, bypassing the technical, socioeconomic, and political challenges that to date have constrained in situ metering. In this paper, we show through a systematic meta-analysis that the relative accuracy of different …