Engineering Commons^™

Modeling Multi-Criteria Decision-Making Problems With Applications In Last Mile Delivery And School Safety Assessment, Ayat Alrahahleh

Theses and Dissertations

The last-mile delivery option has become a focal point of academic research and industrial development in recent years. Multiple factors such as increased demands on delivery flexibility, customer requirements, delivery urgency, and many others are enforcing to adopt this option. For fulfilling this paradigm shift in delivery and providing additional flexibility, drones can be considered as a viable option to use for last-mile delivery cases. Numerous drones are available in the market with varying capacities and functionalities, posing a significant challenge for decision-makers to select the most appropriate drone type for a specific application. For this purpose, this study proposes …

A Novel Method For Sensitivity Analysis Of Time-Averaged Chaotic System Solutions, Christian A. Spencer-Coker

Theses and Dissertations

The direct and adjoint methods are to linearize the time-averaged solution of bounded dynamical systems about one or more design parameters. Hence, such methods are one way to obtain the gradient necessary in locally optimizing a dynamical system’s time-averaged behavior over those design parameters. However, when analyzing nonlinear systems whose solutions exhibit chaos, standard direct and adjoint sensitivity methods yield meaningless results due to time-local instability of the system. The present work proposes a new method of solving the direct and adjoint linear systems in time, then tests that method’s ability to solve instances of the Lorenz system that exhibit …

A Modular Synthesis Of Processable And Thermally Stable Semi-Fluorinated Aryl Ether Polymers Via Step-Growth Polymerization Of Fluoroalkenes, Ketki Eknath Shelar

Theses and Dissertations

Tailored fluoropolymers remain the leading choice for a wide variety of advanced high-performance applications, including electronic/optical and energy conversion, owing to their unique blend of complementary high-performance properties. Amorphous semi-fluorinated polymers exhibit improved solubility and melt processability when compared to traditional perfluoropolymers. A leading class of semi-fluorinated aryl ether polymers includes perfluorocyclobutyl (PFCB), perfluorocycloalkenyl (PFCA), and fluoroarylene vinylene ether (FAVE) polymers. Monomers containing aromatic trifluorovinyl ethers (TFVE) are used to synthesize PFCB polymers via radical-mediated [2+2] cyclodimerization. On the other hand, FAVE and PFCA polymers are polymerized via base-mediated nucleophilic addition/elimination of bisphenols with TFVE monomers and decafluorocyclohexene respectively. The …

Impact Of Climate Oscillations/Indices On Hydrological Variables In The Mississippi River Valley Alluvial Aquifer., Meena Raju

Theses and Dissertations

The Mississippi River Valley Alluvial Aquifer (MRVAA) is one of the most productive agricultural regions in the United States. The main objectives of this research are to identify long term trends and change points in hydrological variables (streamflow and rainfall), to assess the relationship between hydrological variables, and to evaluate the influence of global climate indices on hydrological variables. Non-parametric tests, MMK and Pettitt’s tests were used to analyze trend and change points. PCC and Streamflow elasticity analysis were used to analyze the relationship between streamflow and rainfall and the sensitivity of streamflow to rainfall changes. PCC and MLR analysis …

A Harmonic Radar System For Honey Bee Tracking To Better Understand Colony Collapse Disorder, William B. Woo

Theses and Dissertations

Honey bees are some of the most important pollinators for agriculture in the world and are pivotal to the health of worldwide ecosystems. Like all insects, bees struggle with exposure to parasites, diseases, and other environmental factors that can negatively affect the overall health of the colony. Recently, a new unexplainable phenomenon called Colony Collapse Disorder (CCD) has been wreaking havoc on bee populations worldwide. As a result, a system capable of tracking bees is required to understand the different contributions of chemicals, parasites, etc. to CCD. This research seeks to show data supporting the development of systems for an …

Phase-Field Simulations Of The Precipitation Kinetics And Microstructure Development In Nickel-Based Superalloys, Caleb O. Yenusah

Theses and Dissertations

The continual research and development of nickel-based superalloys is driven by the global demand to improve efficiency and reduce emissions in the aerospace and power generation industries. Integrated Computational Material Engineering (ICME) is a valuable tool for reducing the cost, time, and resources necessary for the development and optimization of the mechanical properties of materials. In this work, an ICME approach for understanding the microstructure development and optimizing the mechanical properties in nickel-based superalloys is employed. Most nickel-based superalloys are precipitate strengthened by either the γ’ phase, γ” phase, or both. Therefore, understanding the precipitation kinetics and morphological evolution of …

Development And Evaluation Of Seasonal, Continental-Scale Streamflow Forecasts, Elissa Marie Yeates

Theses and Dissertations

Methods of forecasting streamflow using atmospheric ensembles and hydrologic routing have greatly improved over the past decades. These forecasts anticipate the timing and magnitude of streamflow peaks, enabling early warning of floods. Recent advances in atmospheric modeling have enabled production of forecasts months ahead, which are less precise but give a useful sense of trends.

The purpose of this study is to produce and evaluate a seasonal streamflow forecast model using a Muskingum routing hydrologic model coupled with runoff from a land surface model, and atmospheric input from a medium-term atmospheric and precipitation model. To evaluate the skill of the …

Challenges And Signal Processing Of High Strain Rate Mechanical Testing, Barae Lamdini

Theses and Dissertations

Dynamic testing provides valuable insight into the behavior of materials undergoing fast deformation. During Split-Hopkinson Pressure Bar testing, stress waves are measured using strain gauges as voltage variations that are usually very small. Therefore, an amplifier is required to amplify the data and analyze it. One of the few available amplifiers designed for this purpose is provided by Vishay Micro-Measurements which limits the user’s options when it comes to research or industry. Among the challenges of implementing the Hopkinson technology in the industry are the size and cost of the amplifier. In this work, we propose a novel design of …

Lattice Boltzmann-Based Sharp-Interface Schemes For Conjugate Heat And Mass Transfer And Diffuse-Interface Schemes For Dendritic Growth Modeling, Nanqiao Wang

Theses and Dissertations

Analyses of heat and mass transfer between different materials and phases are essential in numerous fundamental scientific problems and practical engineering applications, such as thermal and chemical transport in porous media, design of heat exchangers, dendritic growth during solidification, and thermal/mechanical analysis of additive manufacturing processes. In the numerical simulation, interface treatment can be further divided into sharp interface schemes and diffuse interface schemes according to the morphological features of the interface. This work focuses on the following subjects through computational studies: (1) critical evaluation of the various sharp interface schemes in the literature for conjugate heat and mass transfer …

Performance Enhancement Of Wide-Range Perception Issues For Autonomous Vehicles, Suvash Sharma

Theses and Dissertations

Due to the mission-critical nature of the autonomous driving application, underlying algorithms for scene understanding should be given special care during their development. Mostly, they should be designed with precise consideration of accuracy and run-time. Accuracy should be considered strictly which if compromised leads to faulty interpretation of the environment that may ultimately result in accidental scenarios. On the other hand, run-time holds an important position as the delayed understanding of the scene would hamper the real-time response of the vehicle which again leads to unforeseen accidental cases. These factors come as the functions of several factors such as the …

Revealing Quality Of Supportive Healing Environments In Interior Design: Recovered Covid-19 Patients’ Level Of Satisfaction In Isolation Facility Design, Hera Marie T. Barena, Carlo Emmanuel S. Dioquino, Mariel C. Remada

DLSU Senior High School Research Congress

A supportive healing environment is defined as a nurturing and therapeutic setting (Sakallaris et al., 2015). This study aimed to determine the quality of supportive healing environments in the interior design of isolation facilities based on the level of satisfaction of recovered COVID-19 patients. The following objectives guided the study; to determine the quality of supportive healing environments in the interior design of isolation facilities in terms of stimulating design features, complexity and coherence, social support enhancement, and connection to nature. Also, it aimed to determine if there is a significant difference in the quality of supportive healing environments in …

Finite-Difference-Time-Domain Simulation Of Ultrafast Experiments, Alpha Ma

Macalester Journal of Physics and Astronomy

The Finite-Difference-Time-Domain (FDTD) method is a numerical method that calculates electric fields or magnetic fields by interleaving them in space and time. Using a python package called “MEEP”, I was able to write optical simulations of ultrafast experiments, especially the Terahertz Pump-Probe experiments. The goal of this project was to use FDTD simulation to measure the transmission of an electro-magnetic pulse passing through a thin film of conducting material on a dielectric substrate in order to study the characteristic conductivity of potential solar cell materials.

Scandy: Simulating Realistic Human Scanpaths In Dynamic Real-World Scenes, Nicolas Roth, Martin Rolfs, Klaus Obermayer

MODVIS Workshop

No abstract provided.

Santé Le Match, Krizia Mae Araracap, Evan Chou, Matthew Isaac Tolosa

Computer Science and Engineering Senior Theses

In Senegal, many children are unaware of the importance of common hygiene practices due to limited health education on sanitation and personal hygiene. As a result, the repercussions of not following these practices are not clearly understood. This is an issue because some of the most common diseases in Senegal can be prevented through better sanitation practices and other basic preventative measures. Developing hygienic habits at a young age is critical—especially in a developing country such as Senegal. We have created a mobile application that educates and empowers children with the basic knowledge of WASH—water, sanitation, hygiene. Because Senegal often …

Copolymer Microphase Separation, Properties, And Applications, Daniel Weller

Dissertations

Copolymers represent a broad, but critically important class of materials. Often having properties superior to either of its constituents, copolymers are used in virtually all industries including automotive, aerospace, coatings, packaging, and cosmetics. Certain copolymers microphase separate to form nanosized domains that improve the physical properties of the copolymer. The polymer community already has a thorough understanding of how phase separation occurs, but the commercialization of phase separating copolymers lags significantly behind academia. Many of the copolymers that exist that have been undercharacterized and underutilized. This dissertation examines two such polymers. The first, a hard polystyrene material with soft nanodomains. …

Receptor-Doped Organic Transistors: Transducing Anion Binding From Mixed Ionic-Electronic Transport, Anthony Benasco

Dissertations

Organic semiconductors based on π-conjugated polymers show remarkable properties such as high tolerance to structural defects, low processing temperature requirements, biocompatibility, ease of fabrication, and tunable properties. Conjugated polymers integrated into device arrays can exhibit collective properties sensitive to minor perturbations in the surrounding media. However, these devices rely on serendipitous sensitivity to the analyte of interest, and strategies for specific detection remain a considerable change. There remains a compelling, global need for technologies to monitor phosphate due to its prevalence in agricultural runoff, leading to fish kills and economic decline for commercial and recreational fisheries. The strong hydration energies …

Sprouting Systems, Abaigeal Aydt, Cassidy Smith

Honors Program: Expanded Learning Clubs

After taking a class at UNL about environmental awareness, two honors students paired up to start a hydroponics club at a local Lincoln school. In reaching out to the LPS director of sustainability, they were paired up with Prescott Elementary School. Over the course of a semester, they developed a club that got a hydroponic grow tower functioning for the school and taught students about nutrition and sustainability. This club is only in its beginning stages, but the impacts that it is making around the school can already be seen.

Development Of An Analytical Method For Design Of Electromagnetic Energy Harvesters With Planar Magnetic Arrays, Mohsen Amjadian, Anil K. Agrawal, Hani H. Nassif

Civil Engineering Faculty Publications

In this paper, an analytical method is proposed for the modeling of electromagnetic energy harvesters (EMEH) with planar arrays of permanent magnets. It is shown that the proposed method can accurately simulate the generation of electrical power in an EMEH from the vibration of a bridge subjected to traffic loading. The EMEH consists of two parallel planar arrays of 5 by 5 small cubic permanent magnets (PMs) that are firmly attached to a solid aluminum base plate, and a thick rectangular copper coil that is connected to the base plate through a set of four springs. The coil can move …

Simulation Of Thermal Radiation Transport In Stochastic Media With Nonlinear Temperature Dependence, Corey Michael Skinner

Nuclear Engineering ETDs

Nonlinear gray thermal radiation transport (TRT) in binary statistical mixtures is investigated through Implicit Monte Carlo (IMC) simulation on one-dimensional planar Markovian geometries and two dimensional approximate Markovian or Poisson-Box geometries. A stochastic geometry option was implemented in the Los Alamos National Laboratory Branson IMC solver which yielded benchmark solutions by simulating thermal radiation and material energy transport over a large number of instantiations of the geometry followed by ensemble averaging to obtain conditionally averaged radiation intensity and material temperatures. A chord length sampling method was also implemented based on a heuristic generalization of the Levermore-Pomraning homogenized medium model to …

Experimental And Numerical Study Of Novel Coanda-Based Unmanned Aerial Vehicle, Zaid Feroz Siddiqi

Theses and Dissertations

To alleviate the thrust losses in radial direction experienced in conventional saucer-shaped Coanda Unmanned Aerial Vehicles (UAV), a rectangular, linear arrangement of the Coanda surface is adopted in the novel design. This arrangement minimizes the area change in the radial direction to recover such thrust losses. A prototype of the proposed UAV structure is 3D printed and assembled with a single 9-inch propeller. In addition, a custom-built dynamometer is designed specifically to measure propeller thrust under different loading conditions. Performance characteristics of the UAV are evaluated through static testing on the dynamometer which uses a load cell to measure the …

Real Time Audio Processing Using A Low-Power Digital Signal Processor, Aaron Norlinger

Honors Program: Senior Projects (Public)

This project focused on the creation of a series of audio processing functions that could run in real time on the ezDSP5502 processor. The Digital Signal Processor (DSP) being used for this project is an industry standard for lowpower signal processing applications. The overall goal was to have a code base that could sample audio in real time from any source, filter it in a variety of ways, run a Fast Fourier Transform on the audio, display the resulting frequency data to an LCD screen, and then output the filtered audio to an external speaker. This general process is used …

A Broadband Cp Elliptical-Slot Antenna For Ambient Rf Energy Harvesting, Khatereh Nadali, Patrick Mcevoy, Max Ammann

Conference papers

In this paper, a compact broadband CPW-fed circularly polarised elliptical-slot antenna with an inverted- L tuning stub is proposed. The antenna impedance is optimized for broadband operation from 1.62 GHz to 2.97 GHz. The measured CP bandwidth is 934 MHz (1.747-2.681 GHz), that covers common wireless communication bands GSM 1800, GSM 1900, 3G/LTE 2100, 3G/LTE 2300, 4G/LTE 2500, and 2.4GHz Wi-Fi bands. This makes the designed antenna an appropriate candidate for ambient RF energy harvesting purposes.

Molecular-Level Control Over Ionic Conduction And Ionic Current Direction By Designing Macrocycle-Based Ionomers, Shyambo Chatterjee, Ehsan Zamani, Seefat Farzin, Iman Evazzade, Oghenetega Allen Obewhere, Tyler James Johnson, Vitaly Alexandrov, Shudipto Konika Dishari

Department of Chemical and Biomolecular Engineering: Faculty Publications

Poor ionic conductivity of the catalyst-binding, submicrometer- thick ionomer layers in energy conversion and storage devices is a huge challenge. However, ionomers are rarely designed keeping in mind the specific issues associated with nanoconfinement. Here, we designed nature-inspired ionomers (calix-2) having hollow, macrocyclic, calix[4]arene-based repeat units with precise, sub-nanometer diameter. In ≤100 nm-thick films, the in-plane proton conductivity of calix-2 was up to 8 times higher than the current benchmark ionomer Nafion at 85% relative humidity (RH), while it was 1−2 orders of magnitude higher than Nafion at 20−25% RH. Confocal laser scanning microscopy and other synthetic techniques allowed us …

Environmental Impact And Life Cycle Assessment Of Biomass Supported Power Systems For Rural Communities, Hariteja Nandimandalam

Theses and Dissertations

Dependence on fossil fuels in the electric sector is one of the major contributors towards Greenhouse gas (GHG) emissions. The increase in renewable contribution has been observed in recent years but there is still potential to utilize wood waste in rural communities for electricity generation promoting energy independence and sustainable development. For this study, a life cycle assessment approach was utilized to estimate the emissions of electricity produced from wood residue in a rural community. Therefore, the process from planting to supply for bioenergy facility to generate electricity are included. The results showed a decrease of 92-96 % in global …

An Optimization Modeling Framework To Evaluate Civilians Response Under Active Shooter Violence Situations, Joseph G. Kerlin

Theses and Dissertations

Workplace safety is under serious threat due to the increasing trend of active shooter violence in recent years. Therefore, it becomes essential that the safety of a workplace is rigorously and, most importantly, methodologically assessed against active shooter violence. To serve this purpose, this study proposes a machine learning-optimization framework to assess the safety of a building against possible active shooter violence. First, several state-of-the-art machine learning models are employed to predict an agent’s movement decisions (with directions) under different violence scenarios. The predictions are then utilized in a mixed-integer linear programming model to maximize the agent’s utility under a …

Enhancing The Performance Of Dowel Type Fasteners And A Case Study Of Timber Truss Failure, Lon A. Yeary

Theses and Dissertations

This document will outline the findings of three separate and independent studies: Study 1: In or around 1972, an experimental building was constructed. One of the intents of the construction project was to demonstrate advancements in wood building construction design. It was value-engineered throughout. That is, its materials and systems were intended to function at or near design capacity. In 2019, part of the roof of the structure collapsed. This case study investigates two potential factors that led to the failure: stress concentration in excess of the 12 allowable stress for 2 × 4 web members and insufficient plywood sheathing …

Systemic Opportunities To Improve Older Pedestrian Safety: Merging Crash Data Analysis And A Stakeholder Workshop, Jason C. Anderson, Sirisha Kothuri, Christopher M. Monsere, David S. Hurwitz

Civil and Environmental Engineering Faculty Publications and Presentations

This paper presents a framework for improving older pedestrian safety in regard to serious (fatal and incapacitating) crashes, using Oregon as a case study. On review of state and federal practices pertaining to older pedestrian safety, 4 years of crash data identified 112 older (≥ 65 years) pedestrian serious injury crashes. These data were explored for factors that might be addressed systemically using two methods. First, raw frequencies in the crash data were assessed to determine trends and crash-related factors that are overrepresented. Second, a random forest analysis was conducted to determine important variables for predicting older pedestrian serious injury …

Monolithically Integrated Microscale Pressure Sensor On An Optical Fiber Tip, Jeremiah C. Williams, Hengky Chandrahalim

AFIT Patents

A passive microscopic Fabry-Pérot Interferometer (FPI) pressure sensor includes an optical fiber and a three-dimensional microscopic optical enclosure. The three-dimensional microscopic optical enclosure includes tubular side walls having lateral pleated corrugations and attached to a cleaved tip of the optical fiber to receive a light signal. An optically reflecting end wall is distally engaged to the tubular side walls to enclose a trapped quantity of gas that longitudinally positions the optically reflecting end wall in relation to ambient air pressure, changing a distance traveled by a light signal reflected back through the optical fiber.

Evaluation Of Selected Computer Software For Concussion Recovery And Diagnosis, J.P. Jensen

Honors Program: Senior Projects (Public)

Acquired traumatic brain injuries, such as concussions, impact many athletes participating in sports, particularly at the high school, collegiate, and professional levels. The risks posed by concussions – particularly when an athlete suffers repeated injuries – demands that protocols and tools be developed to maximize athlete health and safety. Computer technology can perform critical roles in the analysis and management of concussions. While specialized devices in the areas of imaging and impact sensing, are most associated with concussion management, researchers within the last two decades have increasingly explored the incorporation of various consumer technologies into the identification and treatment of …

Data Management In Web Applications To Balance Performance And Security, Caleb Marcoux

Honors Program: Senior Projects (Public)

As web applications become increasingly popular, many are running several calculations and data processing on the client machine, it is important to consider data management practices on the front-end of these web applications. Typically, some data from the server is stored in the client's memory or hard disk. How much data should be stored for how long, as well as many other considerations, influence the time and space performance of the web application, as well as its security. In this thesis, we explore several challenges, solutions, and design patterns in web application data management through the lens of a senior …