Engineering Commons^™

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 …

Supplier Performance Scorecard Utilization In The Medical Device Manufacturing Healthcare Supply Chain, Justin Cardisco

Theses and Dissertations

The medical device manufacturing industry has a deficiency in determining how to improve supplier performance for the components and systems they purchase. Many complex medical devices require components from superb suppliers. But how does a medical device manufacturer (MDM) impartially assess supplier performance to know which suppliers to continuing with (or even boost purchase volumes) and which suppliers they should exit? This study describes which supplier-specific metrics are most important to medical device manufacturers (MDMs) so they can utilize this supplier performance scorecard backed by real-world inputs. This research will focus on five categories to measure MDM supplier performance (Quality, …

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 …

Direct Simulation And Reduced-Order Modeling Of Premixed Flame Response To Acoustic Modulation, Zheng Qiao

Theses and Dissertations

This dissertation introduces a general, predictive and cost-efficient reduced-order modeling (ROM) technique for characterization of flame response under acoustic modulation. The model is built upon the kinematic flame model–G-equation to describe the flame topology and dynamics, and the novelties of the ROM lie in i) a procedure to create the compatible base flow that can reproduce the correct flame geometry and ii) the use of a physically-consistent acoustic modulation field for the characterization of flame response. This ROM addresses the significant limitations of the classical kinematic model, which is only applicable to simple flame configurations and relies on ad-hoc models …

Analysis And Implementation Of Low Fidelity Radar-Based Remote Sensing For Unmanned Aircraft Systems, Matthew Duck

Theses and Dissertations

Radar-based remote sensing is consistently growing, and new technologies and subsequent techniques for characterization are changing the feasibility of understanding the environment. The emergence of easily accessible unmanned aircraft system (UAS) has broadened the scope of possibilities for efficiently surveying the world. The continued development of low-cost sensing systems has greatly increased the accessibility to characterize physical phenomena. In this thesis, we explore the viability and implementation of using UAS as a means of radar-based remote sensing for ground penetrating radar (GPR) and polarimetric scatterometry. Additionally, in this thesis, we investigate the capabilities and implementations of low-cost microwave technologies for …

Recognizing Traffic Signaling Gestures Through Automotive Sensors., Benjamin James Bartlett

Theses and Dissertations

As technology advances with each new day, so do the applications and uses of the different modalities of technology, including transportation, particularly in ADAS vehicles. These systems allow the vehicle to avoid collisions, change lanes, adjust the vehicle’s speed, and more without the need of driver input. However, each sensor type has a weakness, and most advanced driver- assisted system (ADAS) vehicles rely heavily on sensors, such as RGB cameras, radars, and LiDAR sensors. These visual-based sensors may collect very noisy data in cloudy, raining, foggy, or other obscuring phenomena. Radar, on the other hand, does not rely on visual …

Photocatalytic Degradation Of Organic Contaminants By Titania Particles Produced By Flame Spray Pyrolysis, Noah Babik

Theses and Dissertations

Advanced oxidation of organic pollutants with TiO2 photocatalysts is limited due to the wide bandgap of TiO2, 3.2 eV, which requires ultraviolet (UV) radiation. When nanosized TiO2 is modified by carbon doping, charge recombination is inhibited and the bandgap is narrowed, allowing for efficient photodegradation under visible light. Here, we propose a flame spray pyrolysis (FSP) technique to create TiO2. The facile process of FSP has been successful in preparing highly crystalline TiO2 nanoparticles. Using the same procedure to deposit TiO2 onto biochar, the photocatalyst was doped by the carbonaceous material. The morphology, crystalline and electronic structure of the FSP …

The Effects Of Ecological Simulation For Ground Vehicle Mobility Forecasting, Christopher R. Hudson

Theses and Dissertations

Unmanned ground vehicles (UGV) are being explored for use in military domains. Military UGVs operate in complex off-road environments. Vehicle mobility forecasting plays an important role in understanding how and where a vehicle can operate. Traditional mobility forecasting has been done using an analytical model known as the NATO Reference Mobility Model (NRMM). There has been a push to extend the forecasting capabilities of NRMM by integrating more simulation methods. Simulation enables the repeated testing of UGVs in scenarios that would be difficult or dangerous to study in real world testing. To accurately capture UGV performance in simulation, the operating …

Assessment Of Mechanical Engineering Skills: A Synthesis Of Industry And Academic Graduate Level Curriculum Requirements, Francie Baker

Theses and Dissertations

Students who graduate with an advanced degree in mechanical engineering are a diverse group in their path to post-baccalaureate degree attainment. Some students choose to obtain their master’s or Ph.D. post bachelors, but before they enter the workplace. Others enter the workforce and return as full-time students or progress on their advanced degrees while maintaining part- or full-time employment. Current accreditation standards for undergraduate degree programs are part of a changing landscape of standards and professional requirements that have adapted and continue to adapt as programs prepare students to work in professional engineering fields. Advanced degrees do not have the …

Design, Construction, And Characterization Of A Test Stand Used To Test Filter Media, Adam W. Parsons

Theses and Dissertations

Air filters are routinely used to remove various aerosols ranging from radioactive particles to airborne viruses. The overall performance of a filter may be simplified to consider only two main performance characteristics: 1) the efficiency at which particles are removed by the filter, and 2) the filter’s resistance to air flow. Per the DOE Nuclear Air Cleaning Handbook, HEPA filters require a minimum filter efficiency of 99.97% for particles 0.3 micrometers in diameter. Understanding how filters will perform with respect to time and mass loading is essential towards building more robust filters that operate more efficiently and safely. Analyzing the …

A Comparative Study On The Functionality Of Porcine Dura As A Tissue-Engineered Dura Mater Graft For Clinical Applications, Ashma Sharma

Theses and Dissertations

Damage to dura mater may occur during intracranial or spinal surgeries, which can result in cerebrospinal fluid leakage as well as other potentially fatal physiological changes. As a result, biological scaffolds derived from xenogeneic materials are typically used to repair and regenerate dura mater post intracranial or spinal surgeries. In this study we explore the mechanics, structure, and immunological capacity of xenogeneic dura mater to be considered as a replacement for human dura. A comparative analysis is done between native porcine dura and a commercially available bovine collagen-based dura graft. Native porcine dura mater was decellularized and subjected to mechanical …

Spatial-Spectral Analysis In Dimensionality Reduction For Hyperspectral Image Classification, Chiranjibi Shah

Theses and Dissertations

This dissertation develops new algorithms with different techniques in utilizing spatial and spectral information for hyperspectral image classification. It is necessary to perform spatial and spectral analysis and conduct dimensionality reduction (DR) for effective feature extraction, because hyperspectral imagery consists of a large number of spatial pixels along with hundreds of spectral dimensions.

In the first proposed method, it employs spatial-aware collaboration-competition preserving graph embedding by imposing a spatial regularization term along with Tikhonov regularization in the objective function for DR of hyperspectral imagery. Moreover, Collaboration representation (CR) is an efficient classifier but without using spatial information. Thus, structure-aware collaborative …

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 …

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.

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 …

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 …

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 …