Engineering Commons^™

Unmanned Aerial Vehicle (Uav)-Based High-Throughput Phenotyping For Maize Improvement, Eric T. Rodene

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Modern breeding programs rely heavily on efficiently screening large numbers of genotypes for agronomic traits, such as disease resistance, drought tolerance, and yield. Identifying the genetic loci or genes associated with these traits using GWAS or functional analyses will benefit future plant breeding efforts seeking to incorporate these traits into new crop varieties, whether through conventional breeding or gene editing techniques. Unmanned aerial vehicle (UAV)-based image data has been increasingly used for this task, as it allows entire test plots to be quickly and cost-effectively phenotyped. In my research, I have developed methods to improve the accuracy of machine learning …

Growth And Simulation Of Dielectric-Metal Nanoheterostructured Thin Films By Ballistic Deposition, Shawn Wimer

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

This thesis is divided into two related topics: the structural and chemical characterization of dielectric-metal nanoheterostructured thin films grown by glancing angle deposition (GLAD) and the results of the simulated growth of films and structures by GLAD with discrete-space and continuous-space Monte Carlo ballistic simulation.

Individual structures comprising films grown by GLAD were investigated by S/TEM and SEM imaging, electron diffraction, and chemical characterization and mapping by EDX. Different intermolecular interactions within and between different materials, including Si, Ag, Au, and ZrO₂, are linked to differences in the shapes of individual materials in heterostructures, the shape of heterostructures …

Laser 3d Printing Of Diamond-Based Composite Materials For Thermal Management Applications, Nada Kraiem

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

With the trend towards miniaturization of electrical equipment and the constant increase in power density in semiconductor devices, efficient heat management has become a major concern for researchers. Indeed, this technological evolution imposes increasingly strict constraints in terms of thermal dissipation, necessitating innovative solutions to ensure better durability and reliability of components. In this context, the use of composite materials offering high thermal conductivity (TC) and low coefficient of thermal expansion (CTE) compared to pure metals has become essential to address overheating issues in electronic components.

The utilization of advanced materials such as diamond (D), with exceptional TC and hardness …

Advancements In Microscale Tensile Testing: A Novel Device For The High Throughput Analysis Of Two-Photon Polymerized Microfibers In Liquid, Grayson D. Minnick

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Two-photon polymerization (TPP) enables the 3D fabrication of micro- and nanostructures from biocompatible materials with high resolutions, reaching into the realm of hundreds of nanometers. Such capabilities are crucial for advancing applications in fields like mechanobiology. As microscale technologies evolve, the precise characterization of material properties becomes increasingly essential. This is especially true for TPP-printed microstructures serving as scaffolds for 3D cell culture and intended for studying the mechanics of tissues. Despite the importance, traditional micro-scale tensile testing methods typically lack scalability and fail to replicate relevant environmental conditions. This dissertation introduces a new device that is specifically designed to …

Influence Of The Work Environment On Workplace Learning Of Undergraduate Engineering Interns, Yashin Brijmohan

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Internships are an impactful form of workplace learning that helps undergraduate engineering students acquire and enhance competencies to improve their employability. However, the nuances about what makes an internship successful are not well understood. Furthermore, learning during engineering internships has not been thoroughly researched. Previous literature has mostly focused on internship outcomes, and there is little discussion on how to improve internship experiences to achieve the expected outcomes. Thus, this qualitative study explored the workplace learning environment of internships and how engineering undergraduate students engaged with workplace learning. The study has produced a comprehensive framework that illustrates important factors in …

Dual Light Emission Of Cssni3-Based Powders Synthesized Via A Mechanochemical Process, Xuan Huang, Xiaobing Tang, Xiyu Wen, Yuebin Charles Lu, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

Lead toxicity has hindered the wide applications of lead halide perovskites in optoelec- tronics and bioimaging. A significant amount of effort has been made to synthesize lead-free halide perovskites as alternatives to lead halide perovskites. In this work, we demonstrate the feasibility of synthesizing CsSnI3-based powders mechanochemically with dual light emissions under ambi- ent conditions from CsI and SnI2 powders. The formed CsSnI3-based powders are divided into CsSnI3-dominated powders and CsSnI3-contained powders. Under the excitation of ultraviolet light of 365 nm in wavelength, the CsSnI3-dominated powders emit green light with a wavelength centered at 540 nm, and the CsSnI3-contained powders …

Investigation Of Emissions Characteristics Of Natural Gas Engines With Prechamber Enabled Mixing Controlled Combustion, Johnathan Michael Ronsman

Master's Theses (2009 -)

Increasingly stringent emissions regulations have motivated the exploration of ways to decarbonize the internal combustion engine (ICE). Alternative fuels are of interest as they can easily be implemented with existing infrastructure. Among these alternative fuels, natural gas stands out due to its large abundance and high hydrogen-to-carbon ratio, which can significantly reduce CO2 emissions. Due to its low reactivity, most natural gas engines today are premixed lean burn spark ignited (SI) engines. These engines produce criteria pollutants, such as nitrogen oxides (NOx) and carbon monoxide (CO), but due to their premixed nature, also produce relatively large amounts of unburned methane …

Design And Verification Of A Planar, Programmable, Compliant Hand For Use In General Open-Loop Constrained Manipulation, Jacob Frye

Master's Theses (2009 -)

Conventional robots are adept at performing tasks where the desired absolute position of the robot's end effector is well defined. However, these robots will struggle with tasks in which the desired position is poorly defined, subject to variation, or determined by contact with a constraint with positional uncertainty. This problem can be solved by introducing compliance to the system, either active or passive. Active compliance uses force feedback to make corrective motions, but is limited in speed and experiences higher contact forces than passive systems. Passively compliant systems are capable of realizing the necessary compliance for a given task but …

Advancing Understanding Of Opinions, Perceptions, And Knowledge In Underrepresented Communities In The El Paso Region To Promote Electric Vehicles And Electrified Infrastructure Use To Reduce Environmental Impacts, Liliana Lozada-Medellin

Open Access Theses & Dissertations

As the transportation and automotive industries continue growing, environmental and human health impacts remain a growing concern for planners, policy-makers, constructors, and the public as well (Krause et al., 2013; Larson et al., 2014). Although Electric Vehicles (EVs) are entering the market as a green technology solution to counteract greenhouse gas (GHG) emissions from internal combustion engine vehicles (ICEVs), there are still barriers that need to be overcome for widespread diffusion and adoption as the best solution. These include disseminating basic information about the technology for public awareness, considering equity concerns, and ensuring equitable access to infrastructure for all (L. …

Improving Performance Of Tpu By Controlled Crosslinking Of Soft Segments, Lucivan P. Barros Jr., Lucio R. De Souza, Rasoul Rahimzadeh, Ica Manas-Zloczower

Faculty Scholarship

Thermoplastic polyurethanes (TPUs) are a family of thermoplastic elastomers with great properties such as high elongation and excellent chemical and abrasion resistance, which are processable by conventional melting methods. Nevertheless, TPUs lose mechanical properties and thermal stability at higher temperatures. In this work, we designed and synthesized a new TPU with limited crosslinking of the soft segments in order to improve its performance at high temperatures while preserving processability. Additionally, the new TPU maintains its transparency. With the incorporation of 10% trifunctional polyol, the T was increased by 7°C, the storage modulus at room temperature (25°C) was improved by 412 …

Impact Of Non-Thermal Plasma Generated Using Air And Nitrogen On Functional Properties Of Milk Protein Dispersions, Nikitha Modupalli, Md Mahfuzur Rahman

Food Science Faculty Publications and Presentations

This study focuses on improving the functionalities of milk protein concentrate (MPC) using a nonthermal plasma jet and plasma-activated water (PAW) with atmospheric air and nitrogen as source gases. The 5% and 10% MPC dispersions were directly treated with a plasma jet, and PAW was used to make the MPC dispersions. The dispersions were analyzed for changes in protein structure and functional properties. The treatment altered the secondary structure of MPC protein structure by increasing β-components and changing the order of random coils. The solubility of the PAW-treated 5% protein dispersions doubled due to plasma-induced modification of hydrophilic and covalent …

Microstructural Evolution In A Precipitate-Hardened (Fe0.3ni0.3mn0.3cr0.1)94ti2al4 Multi-Principal Element Alloy During High-Pressure Torsion, Matthew Luebbe, Jiaqi Duan, Peipei Cao, Zhaoping Lu, Rinat K. Islamgaliev, Ruslan Z. Valiev, Yuzi Liu, Haiming Wen

Materials Science and Engineering Faculty Research & Creative Works

Multi-principal element alloys demonstrate high strength, thermal stability, and irradiation resistance, making them excellent candidate materials for applications in nuclear reactors and other harsh environments. Some studies have examined the use of high-pressure torsion to strengthen MPEAs through grain size reduction and strain hardening. However, no studies have investigated the effect of HPT on secondary phases (precipitates) within an MPEA. Two alloys, (Fe_0.3Ni_0.3Mn_0.3Cr_0.1)₉₄Ti₂Al₄ containing Ni(Ti, Al) B2 phase, and CrFe σ phase, and single-phase Fe_0.3Ni_0.3Mn_0.3Cr_0.1, were fabricated by casting …

Alternative Applications Of Composite Materials To Reduce Radar Cross Section, Mark Patterson

Mechanical & Aerospace Engineering Theses & Dissertations

The use of carbon nanoparticles and graphene in composite materials has created a foundational shift in enhancing performance across mechanical, thermal, and electrical properties. Such applications are vital in the aerospace industry. However, there has not been such a focus on the material use for reducing radar cross section (RCS). Historically, RCS is minimized by designing sharp geometric shapes to deflect or dissipate the incoming electromagnetic waves away from the receiving antenna. However, these designs are not always optimized for aerodynamics. The goal of this research is to understand the application of composite materials and specifically carbon nanotubes (CNTs) to …

Predicting Iot Distributed Ledger Fraud Transactions With A Lightweight Gan Network, Charles Rawlins, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

Decision-making and consensus in traditional blockchain protocols is formulated as a repeated Bernoulli trial that solves a computationally intense lottery puzzle, called Proof-of-Work (PoW) in Bitcoin. This approach has shown robustness through practice but does not scale with increasing network size and generation of new transactions. Resource constrained Internet of Things (IoT) networks are incompatible with full computation of schemes like Bitcoin's PoW. Our effort proposes a first step towards an alternative consensus using machine learning-based decision-making with prediction of fraud transactions to alleviate need for intense computation. To improve base approval probabilities for fraud detection in an ideal security …

Machine Learning Approaches To The Exploration Of Ammonia Synthesis Catalysts Utilizing Experimental Data, Rasika Jayarathna

Theses and Dissertations

Traditional heterogeneous catalyst discovery process relies upon human expert-guided experiments based on domain knowledge and human intuition supported by catalyst characterization. However, this process is time and resource-consuming and suffers from human bias. Machine learning (ML) models trained on experimental data have the potential to significantly accelerate this discovery process by guiding experiments to optimize the catalyst performance and increase the understanding of the catalysts. Ammonia synthesis catalysts are a class of catalysts widely investigated in the literature, which has generated decades of experimental data. Moreover, ammonia has been gaining attention since it can be used as a carbon-free next-generation …

Parallel Communications In Single-Core Optical Fibers Utilizing Spatial Domain Multiplexing And Wavelength Division Multiplexing, Mingxuan Tu

Theses and Dissertations

This endeavor proposes a hybrid parallel optical communication architecture in single-core fibers combining WDM in O-band (1270 nm, 1310 nm, 1310 nm, and 1330 nm) and two-channel SDM. The proposed architecture applies carefully designed delays in each propagating channel to achieve synchronization and, therefore, realizes parallel transmission in single-core fibers without the help of Serializer/De-serializers (SerDes). A mathematical model of SDM, calculations on delays between each optical channel, simulation of the hybrid architecture, experimental setup, and the testing and analysis of channel performance have been provided. A design of a photonic integrated circuit based on thin film lithium niobate electro-optic …

Development Of A Mechanical Boot For Prevention Of Deep Vein Thrombosis In Outpatients, Julian David Trevino

Theses and Dissertations

This work presents the development of a mechanical boot designed to prevent Deep Vein Thrombosis (DVT) in high-risk individuals such as those who have just had major procedures. DVT is a serious condition characterized by the formation of blood clots in the deep veins, particularly of the lower limbs, which can lead to life-threatening complications if not adequately addressed. The mechanical boot utilizes the principle of Continuous Passive Motion (CPM) to facilitate blood flow in the lower extremities, thereby mitigating the risk of clot formation. Through a combination of mechanical engineering, biomedical research, and user centered design, the project outlines …

Building Sevices Engineering July/August 2024

Building Services Engineering

No abstract provided.

Solving Unsteady Potential Flow Problems In O(N) Time, Ryan Anderson, Andrew Ning

Faculty Publications

Design of vertical takeoff and landing aircraft is challenging in part due to significant aerodynamic interactions between rotors and wings. Computational models can aid in their design, but are computationally expensive. 3-D panel methods coupled with vortex particle wakes offer an attractive solution, but solving for the panel strengths scales poorly for large problems. Multigrid methods, such as Krylov subspace methods in conjunction with the fast multipole method (FMM), have been demonstrated to reduce the scaling to O(𝑁). We explore the performance and limitations of the Krylov-FMM method, traditional matrix-powered GMRES, LU decomposition, and a novel O(𝑁) multigrid approach to …

Fine-Grained Passenger Load Prediction Inside Metro Network Via Smart Card Data, Xiancai Tian, Chen Zhang, Baihua Zheng

Research Collection School Of Computing and Information Systems

Metro system serves as the backbone for urban public transportation. Accurate passenger load prediction for the metro system plays a crucial role in metro service quality improvement, such as helping operators schedule train timetables and passengers plan their trips. However, existing works can only predict low-grained passenger flows of origin-destination (O-D) paths or inflows/outflows of each station but cannot predict passenger load distribution over the whole metro network. To this end, this paper proposes an end-to-end inference framework, PIPE, for passenger load prediction of every metro segment between two adjacent stations, by only utilizing smart card data. In particular, PIPE …

Response To Replication Stress And Maintenance Of Genome Stability By Wrn, The Werner Syndrome Protein, David K. Orren, Amrita Machwe

Markey Cancer Center Faculty Publications

Werner syndrome (WS) is an autosomal recessive disease caused by loss of function of WRN. WS is a segmental progeroid disease and shows early onset or increased frequency of many characteristics of normal aging. WRN possesses helicase, annealing, strand exchange, and exonuclease activities and acts on a variety of DNA substrates, even complex replication and re- combination intermediates. Here, we review the genetics, biochemistry, and probably physiological functions of the WRN protein. Although its precise role is unclear, evidence suggests WRN plays a role in pathways that respond to replication stress and maintain genome stability particularly in telomeric regions.

Investigation Of Ethane Dehydrogenation And Hydrogenolysis On Pt(111), Pt(211) And Pt(100): Bayesian Quantification And Correction Of Dft-Based Enthalpic And Entropic Uncertainties, Mubarak Bello

Theses and Dissertations

Computational investigations of heterogeneously catalyzed reactions using density functional theory (DFT) are often inaccurate, largely due to uncertainties in the choice of DFT functional (enthalpic uncertainty) and approximations for modeling adsorbate movement along the catalyst surface (entropic uncertainty). This work illustrates that both uncertainties are significant in the investigation of the ethane dehydrogenation (EDH) and hydrogenolysis on Pt catalysts by considering the complete deconstruction of ethane on Pt(111), Pt(211), and Pt(100) using microkinetic modeling (MKM). Hence, this work uses both non-calibrated and Bayesian calibrated MKMs to quantify and correct inaccuracies in macroscopic properties due to both uncertainties. A Bayesian approach …

Exploring Shape Dependency Of Catalysts For Chemical Reactions, Kaveh Shariati

Theses and Dissertations

Recent advancements in the synthesis of nanoparticles, particularly one-dimensional (1D) nanoparticles, have significantly enhanced the catalytic activity of various processes by enabling precise control over their morphologies and exposing unique crystallographic facets. The shape of nanoparticles is closely linked to their chemical, physical, electrical, optical, magnetic, and catalytic properties. This dissertation investigates the impact of 1D nanoparticle catalysts on two distinct and well-known chemical reactions. In the first part of the study, we explore the catalytic activity and selectivity of silver catalysts in the ethylene epoxidation reaction, which are intrinsically linked to their faceting. Silver nanowire catalysts representing Ag(100) and …

Design And Development Of A Direct Medium Voltage Solar Pv Resonant Inverter, Parthkumar Sureshkumar Bhuvela

Theses and Dissertations

In a grid-tied photovoltaic (PV) system connected to a medium voltage (MV) grid, an inverter is generally employed with a line frequency transformer (LFT) to connect to the grid. These LFTs are large in size and weight, exhibit high cost and losses. In recent studies, the LFTs replaced by are by (high frequency transformer) HFT embedded in DC-DC converters. These DC-DC converters are used to boost voltage levels and DC-AC inverters are employed for MV inversion. This leads to high frequency switching at MV which increases losses in inversion stage. In this study, a novel MV grid-connected solar PV inverter …

Enhancing Water Sustainability In North Africa: Literature Review And Synthesis Of Current Knowledge Gaps In Sudan, Osman M. A. Adam, Aaron R. Mittelstet, Derek M. Heeren, Troy E. Gilmore

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

This study delves into the critical role of groundwater in addressing global water challenges, with a focus on the Nubian Sandstone Aquifer System (NSAS) in North Africa. Groundwater constitutes a source of potable water, irrigation, and industrial use, especially in arid regions where surface water is limited. We analyzed the status of water quantity, withdrawals, recharge, and geological characteristics in the NSAS, specifically in Sudan, Egypt, Libya, and Chad. Though the NSAS is largely an untapped resource, we evaluated various scenarios to determine the quantity of cropland that can be sustainably irrigated. The NSAS is located in an arid region, …

Assessing Soil Properties For Optimized Irrigation Development In Sudan, Northern Africa, Suhib Hamid, Derek M. Heeren, Aaron R. Mittelstet, Saleh Taghvaeian, Randall S. Ritzema

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

Sustainable irrigation methods maximize agricultural productivity in Northern African countries like Sudan. This project evaluates soil properties to develop optimized irrigation strategies for Sudan's arid and semi-arid climate. Assessing soil characteristics such as texture, infiltration rates, and nutrient content informs the selection of modern irrigation systems. Data from 3,192 locations, collected using GPS and ring infiltrometers for infiltration rates, alongside laboratory analyses for soil properties, were employed. A ranking system determined suitable irrigation systems for specific soil classes, considering factors like slope, wind, crop tolerance, available water capacity (AWC), drainage, germination, capital cost, labor cost, maintenance, and evapotranspiration (ET). The …

Reinforcement Learning For Strategic Airport Slot Scheduling: Analysis Of State Observations And Reward Designs, Anh Nguyen-Duy, Duc-Thinh Pham, Jian-Yi Lye, Nguyen Binh Duong Ta

Research Collection School Of Computing and Information Systems

Due to the NP-hard nature, the strategic airport slot scheduling problem is calling for exploring sub-optimal approaches, such as heuristics and learning-based approaches. Moreover, the continuous increase in air traffic demand requires approaches that can work well in new scenarios. While heuristics rely on a fixed set of rules, which limits the ability to explore new solutions, Reinforcement Learning offers a versatile framework to automate the search and generalize to unseen scenarios. Finding a suitable state observation and reward structure design is essential in using Reinforcement Learning. In this paper, we investigate the impact of providing the Reinforcement Learning agent …

Single-Valued Neutrosophic Mcdm Approaches Integrated With Merec And Ram For The Selection Of Uavs In Forest Fire Detection And Management, Mai Mohamed, Amira Salam, Jun Ye, Rui Yong

Neutrosophic Systems with Applications

In recent times, the world has experienced a rise in the frequency of forest fires. These fires cause severe economic damage and pose a significant threat to human lives. Therefore, it is essential to search for solutions that can help combat fires and detect them early. Once a fire reaches a certain level, it becomes challenging to control it. Various systems have been proposed to collect data and detect forest fires, such as satellites and other traditional methods. However, these solutions have been ineffective in terms of cost, coverage of large areas, accuracy, and the safety of human lives. To …

Understanding And Tuning Magnetism In Layered Ising-Type Antiferromagnet Fepse3 For Potential 2d Magnet, Rabindra Basnet, Taksh Patel, Jian Wang, Dinesh Upreti, Santosh Karki Chhetri, Gokul Acharya, Md Rafique Un Nabi, Joshua Sakon, Jin Hu

Chemistry & Biochemistry Faculty Publications and Presentations

Recent developments in 2D magnetic materials have motivated the search for new van der Waals magnetic materials, especially Ising-type magnets with strong magnetic anisotropy. Fe-based MPX₃ (M = transition metal, X = chalcogen) compounds such as FePS₃ and FePSe₃ both exhibit an Ising-type magnetic order, but FePSe₃ receives much less attention compared to FePS₃. This work focuses on establishing the strategy to engineer magnetic anisotropy and exchange interactions in this less-explored compound. Through chalcogen and metal substitutions, the magnetic anisotropy is found to be immune against S substitution for Se whereas …

Atmospheric Waves Experiment (Awe) Thermal Control System: From Design Through On-Orbit Thermal Performance, Matthew I. Ralphs, Mike Holt

Space Dynamics Laboratory Publications

The Atmospheric Waves Experiment (AWE) will provide the first global characterization of atmospheric waves that originate in Earth’s lower atmosphere and affect space weather. The instrument has been installed on the International Space Station (ISS) ExPRESS Logistics Carrier (ELC) 1 since November 2023. The main thermal control system consists of a passive, ambient temperature, bi-directional radiator to which pyrolytic graphite sheet (PGS) thermal straps connect four independent detectors, whose temperatures are actively controlled by thermoelectric coolers (TECs). This paper discusses the thermal design, thermal model correlation efforts (both with test temperature data and flight temperature data), and how the predictions …