Engineering Commons^™

Standardization Of Risk Classifications For Unmanned Space Vehicle Missions, Collin A. Gwaltney

Theses and Dissertations

This paper seeks to model risk classification levels (A-D) for 122 Space Vehicle programs. Models include multinomial logistic regression as well as random forest, a machine learning technique based on decision trees. We use independent variables (IVs) which are theoretically correlated to risk class for the regression and one random forest model. We then include all IVs and allow the random forest technique to use those which provide the most information on risk class before paring down the number of IVs to only 7. We show that the accuracy of predictions increases from 62% to 87% by using random forest …

Investigation Of The Effect Of Internal Reynolds Number And Advective Capacity Ratio On Gas Turbine Film Cooling Parameters, John P. Di Lella

Theses and Dissertations

The desire for more powerful engines drives higher turbine inlet temperatures and a greater need to cool them. Experimentalists attempt to match cooling effectiveness between two conditions by matching several non-dimensional parameters, one of which is the coolant warming factor. The first investigation of this study examines the effect of the internal Reynolds number and the advective capacity ratio on the coolant warming factor by making use of a computational model and four different gases. It indicates the non-negligible and opposing effects of external convection and solid conduction on the coolant warming factor at matched internal Reynolds number and advective …

Performance Of Humans And Agents In A Systems Modeling Language V2 Task: A User-Centered Evaluation Approach, Allen W. Dukes

Theses and Dissertations

The Department of Defense is adopting Digital Engineering practices for its workforce. Simultaneously, the larger Systems Engineering community strives to modernize and define those Digital Engineering practices. These efforts to move from traditionally document-based approaches to pure digital implementations will require enhanced capabilities to manage and digitally track the lifecycle of a program or product. However, this growth must address tool design through an iterative process focusing on usability for many user types. Many tools and technologies exist but often lack an assessment of usability when engineers design tools for other engineers. Including usability when developing solutions for Digital Engineering …

Influence Of Environmental Barrier Coatings On The Overall Effectiveness Of A Film Cooled Ceramic Matrix Composite Plate, Shane P. Lindsay

Theses and Dissertations

Silicon carbide ceramic matrix composites, a promising new potential upgrade over the conventional metals currently used for jet engine turbine blades, have a propensity to oxidize in a combustion environment. Engine manufacturers often apply environmental barrier coatings to prevent the composites from oxidizing. What is unclear, however, is how environmental barrier coatings effect underlying composite temperatures. This research examined the coatings’ effects by first characterizing the influence of environmental barrier coatings on the underlying temperature of a protected ceramic, then evaluating the significance of lateral conduction for cooling a coated ceramic, and finally comparing cooling results for coated and uncoated …

Rapid Passive Safety Determination Using Backward Reachability For Spacecraft Rendezvous And Proximity Operations, Kealy A. Murphy

Theses and Dissertations

As the prevalence of autonomous space systems rise, there is an urgent demand for robust and precise safety analysis. The future of RPO necessitates coordination of satellites in a dynamic and congested space environment while avoiding collisions. Passive safety in RPO refers to the implementation of strategies that minimize the collision risk in the event of orbital or control deviations. This multifaceted problem includes maintaining KOZ, utilizing predictive modeling to anticipate collision scenarios, and designing spacecraft with robust GNC systems allowing for timely course corrections. The current literature’s focus has been on the separation distance between spacecraft as a primary …

Preliminary Assessment Of Cislunar Disposal Orbits, Ryan M. Sargent

Theses and Dissertations

This thesis investigates the disposal of end-of-life spacecraft from key orbits with a focus on minimizing delta-v expenditure and preventing debris propagation. Simulated Lyapunov and halo orbits around the L2 Lagrange point are analyzed for disposal feasibility. Both impulsive and continuous thrust methods are explored to achieve disposal trajectories. Continuous thrust will be modeled after a Hall thruster utilizing electric propulsion. Leveraging the Circular Restricted Three Body Problem framework, low delta-v cost trajectories are computed, with a multi-level correction algorithm optimizing total delta-v via heteroclinic connections. The study assesses various delta-v amounts for Earth-Moon system escape and evaluates the potential …

Human Performance Modeling Architecture With Hc-130j Mission Application, Stephanie G. Slimp

Theses and Dissertations

The DOD emphasizes digital engineering using Model-Based Systems Engineering (MBSE), where MBSE includes SysML-based models of systems. Analysis of system impacts on the human operators and their performance typically occurs through non-MBSE approaches, if at all. One current process, considered the As-Is process for this research, evaluates human performance and workload using IMPRINT, a discrete event simulation (DES) tool. IMPRINT primarily exists as a standalone tool with limited built-in functionality to integrate with an MBSE tool. Using the HC-130J and its crew during a CSAR mission as the system, this research develops a generalizable and updateable human performance modeling architecture …

Rotorcraft Assisted Aircraft Inspection System: Creation And Component Assessment, Adam J. Warren

Theses and Dissertations

Aircraft require frequent inspections to perform their missions safely. Current visual inspection methods are time-consuming and dangerous for inspection personnel, but they are necessary to spot flaws that could endanger the aircraft during flight. This research explores a set of methods for transforming a set of target inspection criteria into camera specifications that will allow a UAS aircraft inspection system to perform inspections on the top skin of an aircraft. Given the minimum distance for the UAS to fly above the aircraft, minimum flaw size to search for on the aircraft, minimum number of pixels to display that flaw size, …

Impact Of The New Context Functional Classifications For Kytc, Arlen Sandlin, Jill Asher, Nikiforos Stamatiadis, Jeff Jasper, Rachel Catchings, Chris Van Dyke

Kentucky Transportation Center Research Report

State transportation agencies are adopting an expanded context classification system to inform project development and delivery. This system classifies roadways into one of five categories based on factors such as level of development, building densities and setbacks, multimodal user patterns and requirements, network permeability, and speed. Compared to functional classification, context classification better captures the types of mobility, travel patterns, and user mixes observed in specific contexts. The expanded context classification system is found in AASHTO’s A Policy on Geometric Design of Highways and Streets (7^th Edition). The forthcoming 8^th edition will deepen integration of context classification throughout …

Insen 2023 Yearly Updates, Walid Metwally, Matteo Gerlini, Cristen Ford, João Claudio Batista Fiel J.C.B.F., Dr. Alpana Goel

International Journal of Nuclear Security

The International Nuclear Security Education Network (INSEN) is the primary international network for nuclear security educational initiatives. INSEN plays a central role in fostering collaboration and knowledge-sharing among nuclear security education experts worldwide. In the wake of the global pandemic, INSEN remained committed to strengthening nuclear security education and resumed in-person activities. The International Atomic Energy Agency (IAEA) confirmed its continued dedication and support to the network’s mission and presented new activities aimed at elevating global nuclear security efforts.

Throughout the year and during the annual and leadership meetings, working groups showcased their vibrant work and presented innovative ideas, invigorating …

Optimization Of Factors Affecting The Performance Of A Fluidized Bed Dryer, Soner Celen, Sultan Pektas

The Philippine Agricultural Scientist

This study investigated the theoretical, analytical, and experimental effects of parameters such as bed height, air velocity, and air temperature on drying using a fluidized bed dryer. The objective was to examine how these parameters influence the drying process of salt products in a pilot fluidized bed dryer and establish the foundation for the development of a future full-scale machine. Salt products with an initial moisture content of 3% were used in all experimental trials. The pressure drop was determined by calculating the minimum fluidization rate, Archimedes and Reynolds number. The calculated values were compared with the analyses conducted using …

Design, Fabrication, And Determination Of The Optimum Working Conditions Of A Peanut (Arachis Hypogaea L.) Pneumatic Bagging System, Selcuk Ugurluay, Ali Somay

The Philippine Agricultural Scientist

The peanut bagging process is not mechanized, it requires a large amount of human labor. In addition, the shovel or canister used in bagging breaks the peanut shell that causes losses. The purpose of this study is to reduce the required workforce by mechanizing the peanut bagging process, and to determine the optimum working criteria (hose diameter and air velocity) of the prototype machine. A peanut pneumatic bagging machine powered by a tractor power takeoff (PTO) was designed and fabricated to convey peanut pods from the ground and fill the product into the bags. To determine the optimum working conditions …

Effects Of Redrying Methods On The Milling Potential, Crude Protein And Total Phenolic Content, And Antioxidant Activity Of Stored Inorganic And Organically-Grown Paddy, Mary Ann Baradi, Jessica Solero, Clarence Dangcil, Gerome Corpuz, Marissa Romero

The Philippine Agricultural Scientist

This study sought to determine the effects of redrying techniques (no redrying or Control, 2-h, 4-h, and 6-h redrying with stirring every 30 min, Farmer's Practice or 6-h redrying with one stirring) on grain quality of stored inorganic and organic paddy rice as well as the redrying method that gives the best quality rice. PSB Rc82 rice harvested in October 2016 was used in the experiment conducted in February 2017. Quality parameters evaluated were moisture content, brown rice, total milled rice, crude protein content in percent, total phenolic content, and 2-2 diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. PSB Rc82 paddy exposed …

Techno-Economic Feasibility Of Polyhydroxybutyrate (Phb) Production From Corn Stover, Jey-R Ventura, Ruby Lynn Ventura

The Philippine Agricultural Scientist

This research evaluated the techno-economic feasibility of polyhydroxybutyrate (PHB) production using corn stover as a substrate for the fermentation process. The target PHB plant production was set at 1000 t PHB per yr, with a daily production of about 3 t PHB. The required corn stover biomass was around 12 000 t per yr. The economic analysis of this study suggested that 91.13 M US$ is needed to put up the targeted plant production capacity, with 94% of the total investment to be allotted to the direct fixed capital cost. Annual operating cost was rated at 4.71 M US$ per …

Implementation Of Fluid Viscous Damper For 2023 Eeri Seismic Design Competition, Dalton J. Muck, Payton S. Mcgee, Payton R. Filippin, Tynan Castro

Architectural Engineering

The authors of this report were a part of the 2023 Earthquake Engineering Research Institute (EERI) student chapter for California Polytechnic State University, San Luis Obispo (Cal Poly). With thirteen other team members, they traveled to San Francisco, CA to compete in the Seismic Design Competition (SDC) hosted by EERI. The team was tasked with preparing a written proposal, design and computer analysis of the structural system, construction of two physical models, as well as creation of a poster and a presentation for a proposed mid-rise building located in the competition host city. The goal of the design of Cal …

Pl 43 Traffic Forecasting Report 2023, Mei Chen, Xu Zhang, Eugene Antwi

Kentucky Transportation Center Research Report

This document is the seventh edition of the Traffic Forecasting Report (TFR) for the state of Kentucky. TFR data are important for multiple engineering applications that involve analyzing temporal and spatial variability in traffic distributions and volumes. Most of the metrics discussed in the report were computed using data from 2019, 2021, and 2022 — excluded from consideration were 2020 data because they exhibited anomalous traffic patterns tied to shutdowns associated with the COVID-19 pandemic. Data summarized in this report include average daily traffic, annual average daily truck traffic, travel activity by vehicle type, weekday and weekend hourly volume percentages, …

Continual Online Learning-Based Optimal Tracking Control Of Nonlinear Strict-Feedback Systems: Application To Unmanned Aerial Vehicles, Irfan Ganie, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

A novel optimal trajectory tracking scheme is introduced for nonlinear continuous-time systems in strict feedback form with uncertain dynamics by using neural networks (NNs). The method employs an actor-critic-based NN back-stepping technique for minimizing a discounted value function along with an identifier to approximate unknown system dynamics that are expressed in augmented form. Novel online weight update laws for the actor and critic NNs are derived by using both the NN identifier and Hamilton-Jacobi-Bellman residual error. A new continual lifelong learning technique utilizing the Fisher Information Matrix via Hamilton-Jacobi-Bellman residual error is introduced to obtain the significance of weights in …

Dynamic Model Of Ac-Ac Dual Active Bridge Converter Using The Extended Generalized Average Modeling Framework, Kartikeya Jayadurga Prasad Veeramraju, Jonathan W. Kimball

Electrical and Computer Engineering Faculty Research & Creative Works

The ac-ac dual active bridge (DAB) converter is an advanced bidirectional two-port grid interface converter that facilitates active and reactive power flow control between two grids without a dc-link capacitor. This article presents a novel modeling approach for the ac-ac DAB converter using the extended generalized average modeling (EGAM) technique. Unlike the conventional generalized average modeling (GAM) framework, the ac-ac DAB converter's dynamic state variables, including the leakage inductor current and ac grid side LC filters, exhibit grid and switching frequency components, making the standard GAM framework unsuitable for dynamic modeling involving two distinct excitation frequencies. Furthermore, the 2-D GAM …

Random Forests For Detecting Weak Signals And Extracting Physical Information: A Case Study Of Magnetic Navigation, Mohammadamin Moradi, Zheng-Meng Zhai, Aaron Nielsen, Ying-Cheng Lai, Aaron P. Nielsen

Faculty Publications

It has been recently demonstrated that two machine-learning architectures, reservoir computing and time-delayed feed-forward neural networks, can be exploited for detecting the Earth’s anomaly magnetic field immersed in overwhelming complex signals for magnetic navigation in a GPS-denied environment. The accuracy of the detected anomaly field corresponds to a positioning accuracy in the range of 10–40 m. To increase the accuracy and reduce the uncertainty of weak signal detection as well as to directly obtain the position information, we exploit the machine-learning model of random forests that combines the output of multiple decision trees to give optimal values of the physical …

Multilayered Energy Management Framework For Extreme Fast Charging Stations Considering Demand Charges, Battery Degradation, And Forecast Uncertainties, Waqas Ur Rehman, Jonathan W. Kimball, Rui Bo

Electrical and Computer Engineering Faculty Research & Creative Works

To achieve a cost-effective and expeditious charging experience for extreme fast charging station (XFCS) owners and electric vehicle (EV) users, the optimal operation of XFCS is crucial. It is, however, challenging to simultaneously manage the profit from energy arbitrage, the cost of demand charges, and the degradation of a battery energy storage system (BESS) under uncertainties. This article, therefore, proposes a multilayered Mult timescale energy flow management framework for an XFCS by considering long- and short-term forecast uncertainties, monthly demand charges reduction, and BESS life degradation. in the proposed approach, an upper scheduling layer (USL) ensures the overall operation economy …

Designing An Optical Router Based On A Multimode-Interference Silicon-On-Insulator Coupler With Tunable Power Transmittance, Dana S. Akil, Muhammad A. Othman, Sherif M. Sherif, Mohamed A. Swillam

Faculty Journal Articles

The demand on fast and high-bandwidth data transmission is in continuous increase. These demands are highly dependent on optical signal manipulation, including switching, modulation, and routing. We demonstrate a two-port silicon optical router based on the multimode interferometer (MMI) configuration. The same MMI structure was used for both inward and backward waveguiding to reduce the total length of the device. A phase shifter consisting of two ring-like waveguides made of silicon p-n junctions was used to introduce the phase shift needed for optical routing upon voltage application. Two designs for the MMI optical router were studied: Firstly, a conventional MMI …

Lateral Load Response Of Semi-Interlocking Mortarless Masonry-Infilled Frames, Sonam Dorji, Hossein Derakhshan, David P. Thambiratnam, Alireza Mohyeddin

Research outputs 2022 to 2026

Structural frames infilled with masonry material called masonry-infilled frames (MIFs) are common types of constructions around the world. These structures generally have mortared masonry as infill material which made the buildings stiff during past earthquakes and generated additional torsional forces. With a view to improve the seismic performance of MIFs this paper presents the results of a numerical simulation study on the behaviour of previously-tested MIFs with semi-interlocking masonry (SIM) material. In a simplified micro-modelling approach, the concrete and masonry materials are simulated using Concrete Damaged Plasticity technique and the joints are considered as zero-thickness cohesive interfaces modelled using traction-separation …

The Janssen Effect And The Chini Ordinary Differential Equation, Adam Rogers, George Dyck, Jitendra Paliwal, Kurt Hildebrand, Michael D. Montross, Aaron P. Turner

Chemical and Materials Engineering Faculty Publications

The Janssen effect describes the increase in pressure with depth in granular materials. However, the original Janssen formulation treats the density as constant. In this work, we examine parametric density models that depend on both pressure and moisture content and allow for temperature dependence to be easily included. We focus on physically-motivated empirical models that are built on power-law terms. These power-law terms correspond to thermodynamic equations of state, such as the ideal gas law, and polytropic processes. When coupled with the Janssen ordinary differential equation (ODE), these power-law models have the form of a Chini ODE. We study the …

Protocol For Modeling And Simulating Lithiation-Induced Stress In Largely Deformed Spherical Nanoparticles Using Comsol, Yong Li, Yungpeng Guo, Yunhao Wu, Yin Rao, Kai Zhang, Dashun Liu, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

Here, we present a finite element method-based scheme for solving coupled par- tial differential equations (PDEs) for the analysis of lithiation-induced stress in largely deformed spherical nanoparticles via the PDE module in COMSOL. We describe steps for software installation and setting PDEs, initial/boundary condi- tions, and mesh parameters. We then detail procedures for dividing the mesh and analyzing lithium trapping during electrochemical cycling. This protocol can also be extended to analyze a wide range of problems involving diffusion-induced stress. For complete details on the use and execution of this protocol, please refer to Li et al.

Strengthening The Deployment Of Uncrewed Aerial Systems (Uas) At Kytc, Rachel Catchings, Suzanne Smith, Gayle Marks, Candice Wallace, Christopher Van Dyke

Kentucky Transportation Center Research Report

The Kentucky Transportation Cabinet (KYTC) and transportation agencies around the United States increasingly depends on uncrewed aircraft systems (UAS — also commonly known as drones) to collect data and accelerate project development and delivery. Drones let transportation practitioners safely and efficiently perform many activities, including bridge and highway inspection, construction monitoring, surveying, emergency response, and measuring stockpiles. KYTC’s implementation of UAS has expanded rapidly over the past 10 years, however, the agency lacks well-coordinated procedures for connecting pilots with end data users, scheduling and conducting flights, developing and documenting best practices, and processing and storing data. Based on a review …

Best Practices For Recruitment And Retention Of Transportation Professionals, Chris Van Dyke, Bryan Gibson, Sarah Mccormack, Merl Hackbart, Doug Kreis

Kentucky Transportation Center Research Report

Many public sector agencies, including state departments of transportation (DOTs), have long found recruiting and retaining staff a daunting challenge. Lured by the promise of higher salaries in the private sector, many people are reluctant to sacrifice their long-term earnings potential to pursue public service. And with the quality of fringe benefits (e.g., retirement plans, health insurance) offered by public agencies having declined gradually, it is even more difficult to persuade prospective employees to accept a lower salary. Many studies over the past 15—20 years have looked at methods for solving the problem of recruitment and retention within the context …

Pd-Modified Cuo-Zno-Al2o3 Catalysts Via Mixed-Phases-Containing Precursor For Methanol Synthesis From Co2 Hydrogenation Under Mild Conditions, Xiao Fan, Kaiying Wang, Xiaoqing He, Shiguang Li, Miao Yu, Xinhua Liang

Chemical and Biochemical Engineering Faculty Research & Creative Works

A series of palladium-modified (Pd-modified) CuO-ZnO-Al2O3 (CZA) catalysts with various Pd loadings (0.3 wt% to 2.4 wt%) were prepared using the wetness impregnation method, on two CZA supports with different structures that are CZA-aged precursor composed of a mixture of zincian-malachite and hydrotalcite-like phases (CZA-zH), and CuO-ZnO-Al2O3 metal oxide nanoparticles (CZA-MO). Enhancement on catalytic activity can be observed on both Pd-modified CZA catalysts in a temperature range of 180–240 °C for methanol synthesis via CO2 hydrogenation. Pd/CZA-zH catalysts exhibited a more efficient and stable production of methanol at a relatively low reaction temperature of 180 °C for 100 hrs. of …

Weakly Supervised Attention-Based Recognition Under Spectral, Turbulence, And Resource Variations, Kshitij Naresh Nikhal

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

While supervised optimization paradigms are ubiquitous across diverse recognition systems, the risk of over-fitting and increasing bias have limited their applicability.

This dissertation focuses on unsupervised learning—learning without precisely curated data—and argues that unsupervised learning methods can enable both discriminability and generalizability. Through the use of attention-based machine learning and advanced clustering, unsupervised methods are able to focus on fine-grained information in images without any explicit supervision. The dissertation introduces a domain-bridging framework for tasks like cross-spectrum matching and long-range recognition, utilizing intra-domain clustering and inter-domain matching to generate pseudo-labels. Additionally, a hash-based network is proposed to accelerate the search …

An Impedance-Source-Based Soft-Switched High Step-Up Dc-Dc Converter With An Active Clamp, Saeed Habibi, Ramin Rahimi, Mehdi Ferdowsi, Pourya Shamsi

Electrical and Computer Engineering Faculty Research & Creative Works

This article proposes a high step-up dc-dc converter based on a trans-inverse impedance-source structure, in which the voltage gain of the converter is increased by using a lower number of turns ratio of the coupled inductors (CI) windings. The proposed converter achieves a very high voltage gain and a very low voltage stress on the switches. An active clamp is incorporated into the topology of the proposed converter, helping to absorb the energy of the leakage inductances of the CI, and to recycle that energy to the output of the converter to further increase the voltage gain. Furthermore, the active …

Toward Smart And Sustainable Cement Manufacturing Process: Analysis And Optimization Of Cement Clinker Quality Using Thermodynamic And Data-Informed Approaches, Jardel P. Gonçalves, Taihao Han, Gaurav Sant, Narayanan Neithalath, Jie Huang, Aditya Kumar

Electrical and Computer Engineering Faculty Research & Creative Works

Cement manufacturing is widely recognized for its harmful impacts on the natural environment. In recent years, efforts have been made to improve the sustainability of cement manufacturing through the use of renewable energy, the capture of CO₂ emissions, and partial replacement of cement with supplementary cementitious materials. To further enhance sustainability, optimizing the cement manufacturing process is essential. This can be achieved through the prediction and optimization of clinker phases in relation to chemical compositions of raw materials and manufacturing conditions. Cement clinkers are produced by heating raw materials in kilns, where both raw material compositions and processing conditions …