Engineering Commons^™

Novel Structures And Thin Film Techniques For Reconfigurable Rf Technologies With Improved Signal Integrity, Jinqun Ge

Theses and Dissertations

Over the past several decades, wireless communications have been tremendously developed with multiple frequency bands, standards, and functions to provide more convenient communication services. Nowadays, commercial wireless devices, especially customer premises equipment, are required for smaller size, higher integration, and higher data rates to meet the ever-increasing demands of communications. The transceiver front ends inside these devices need to provide high-speed and high-quality communication services without a substantial increase in cost and size. Hence, the primary objective of this research is to develop a few miniaturized, multifunctional, and reconfigurable RF technologies and to provide several signal integrity and heat dissipation …

Multidimensional Transport-Coupled Numerical Investigation Of Non-Premixed Low-Temperature Flame In Atmospheric And High-Pressure Systems, Sudipta Saha

Theses and Dissertations

Gas-phase chemical reactions coupled with multidimensional fluid flow and heat and mass transport are found in various applications, i.e., from conventional engine applications to novel combustion techniques. With the goal of understanding such complex coupling in reacting flow systems, this dissertation work focuses on developing multi-physics simulation frameworks to investigate the effect of multidimensional transport on flame dynamics. This study primarily focuses on the modeling and simulation of low temperature flame formation in i) a canonical experimental setting with counterflow burners and ii) a supercritical water medium (i.e., hydrothermal flame).

In the first part of the dissertation, simulations of the …

Development And The Use Of A New Kinetically Limited Linear Driving Force Model For Diffusion-Based Adsorptive Separations, Sulaimon Adedayo Adegunju

Theses and Dissertations

A new kinetically limited linear driving force (KLLDF) model, in terms of a modified extended Langmuir (EL) isotherm, was developed. This KLLDF model augments the equilibrium driving force in the linear driving force (LDF) model in such a way that the equilibrium loading of each component in the LDF model depends on the actual, kinetically limited, loading of the other components in a gas mixture, not their partial pressures. In contrast, the LDF model assumes the presence of a slower diffusing adsorbate in a gas mixture affects the equilibrium of a faster diffusing adsorbate in a pore structure via its …

Load Rating Evaluation Of Deteriorated Prestressed Channel Girders, Alexander Zane Henderson

Theses and Dissertations

The South Carolina Department of Transportation (SCDOT) is conducting a multi-year effort to load rate its inventory of over 9,400 bridges. This includes many bridges that are load posted due to potential structural considerations (e.g., outdated design loads, members whose capacity is difficult to assess, structural degradation). The number of load-posted bridges in South Carolina is expected to increase significantly due to recent efforts from SCDOT to assess the current state of bridge infrastructure. It is expected that the increased scrutiny may result in more load postings, which in turn may lead to restrictions on truck routes, potential bridge closures, …

Evaluation Of Preferential Vaporization Characteristics Of Isolated Single Droplet Combustion In A Converging Channel, Claire Elizabeth Dixon

Theses and Dissertations

Preferential vaporization of isolated single droplets was evaluated in this study. A previously verified lab-scale experiment using flow acceleration to counteract the effects of buoyancy in a converging channel with a decreasing cross section was utilized to investigate the single isolated droplet combustion. The previous experimentation revealed differences between results and values predicted by a one-dimensional numerical simulation. To investigate if the observed differences were the result of turbulent flow and the development of a boundary layer within the channel, a model was designed and analyzed in Ansys Fluent.

The developed Ansys simulation indicated that turbulent flow and growth of …

Advancing The Engineering Workforce By Enhancing Diversity, Equity, And Inclusion In The Engineering Classroom, Phoneia Hughes Myers

Theses and Dissertations

Society’s dependence on engineered products is steadily increasing. This dependence requires the engineering workforce to continually innovate and design new advancements. In pursuit of this, engineering employers are implementing diversity, equity, and inclusion initiatives to attract prime candidates and retain employees. For employers to achieve the goals of their initiatives, engineering colleges and universities must produce a diverse pool of graduates. The purpose of this thesis report is to investigate how the diversity, equity, and inclusion concept can be implemented into engineering education to assist with producing diverse graduating classes. A universal methodology is proposed to provide a roadmap on …

Utilizing Deep Learning Methods In The Identification And Synthesis Of Gene Regulations, Jiandong Wang

Theses and Dissertations

Gene expression is the fundamental differentiation and development process of life. Although all cells in an organism have essentially the same DNA, cell types and activities vary due to changes in gene expression. Gene expression can be influenced by many gene regulations. RNA editing contributes to the variety of RNA and proteins by allowing single nucleotide substitution. Reverse transcription can alter the expression status of genes by inducing genetic diversity and polymorphism via novel insertions, deletions, and recombination events. Gene regulation is critical to normal development because it enables cells to respond rapidly to environmental changes. However, identifying gene regulations …

Speckle Development And Application In Uav-Based Digital Image Correlation For Transportation Infrastructure Monitoring And Assessment, Taylor Wyatt

Theses and Dissertations

A critical aspect of civil infrastructure is structural health monitoring, of which digital image correlation (DIC) has been proven to be an effective and appropriate method. There is sufficient literature on the use of stationary DIC, but an unexplored aspect is DIC-equipped unmanned aircraft systems. It has been verified in University of South Carolina labs but has not been proved in a field environment. One of the challenges of field implementation is large scale speckle application. This work focusses on identifying and addressing challenges in bringing UAV-DIC technology from the lab to the field. This includes the development of optimized …

Implementation Of The Downlink Communication System Of The Lmu Cubesat, Mohammed Alrabeeah

LMU Theses and Dissertations

In this thesis, we present the design and implementation of a CubeSat receiver system using the Universal Software Radio Peripheral (USRP) and GNU Radio. The goal of this project is to develop a low-cost and flexible ground station capable of receiving telemetry and payload data from CubeSats in real time. The CubeSat receiver operates in the UHF frequency range with a center frequency of 435 MHz and uses a software-defined radio (SDR) approach to provide wideband signal processing and demodulation capabilities. The satellite transceiver transmits an Ax.25 Transciever packet every 1 second using the Pumpkin CubeSat kit programmed in MPLab. …

Downstream Task Self-Supervised Learning For Object Recognition And Tracking, Abubakar Siddique

Dissertations (1934 -)

This dissertation addresses three limitations of deep learning methods in image and video understanding-based machine vision applications. Firstly, although deep convolutional neural networks (CNNs) are efficient for image recognition applications such as object detection and segmentation, they perform poorly under perspective distortions. In real-world applications, the camera perspective is a common problem that we can address by annotating large amounts of data, thus limiting the applicability of the deep learning models. Secondly, the typical approach for single-camera tracking problems is to use separate motion and appearance models, which are expensive in terms of computations and training data requirements. Finally, conventional …

Probabilistic Model Development And Risk Management Strategies For Pipelines With Anomalies, Kiswendsida Jules Kere

Dissertations (1934 -)

Metal pipelines are exposed to many threats such as corrosion and cracking during their service life, which can weaken pipeline integrity and cause leaks or ruptures, leading to significant safety, economic and environmental consequences. For corrosion, many models have been developed to predict failure pressure of pipeline with an isolated defect, and only a few models consider interacting defects. On the other hand, the existing models for predicting failure pressure of pipeline with crack defects are very limited. Several model performance evaluations have shown that most of the existing models for either corrosion or cracking-like defects are conservative since they …

Design And Advanced Model Predictive Control Of Wide Bandgap Based Power Converters, Waqar Ahmed Khan

Dissertations (1934 -)

The field of power electronics (PE) is experiencing a revolution by harnessing the superior technical characteristics of wide-band gap (WBG) materials, namely Silicone Carbide (SiC) and Gallium Nitride (GaN). Semiconductor devices devised using WBG materials enable high temperature operation at reduced footprint, offer higher blocking voltages, and operate at much higher switching frequencies compared to conventional Silicon (Si) based counterpart. These characteristics are highly desirable as they allow converter designs for challenging applications such as more-electric-aircraft (MEA), electric vehicle (EV) power train, and the like. This dissertation presents designs of a WBG based power converters for a 1 MW, 1 …

Computationally Efficient Analysis And Optimization Of Induction Motors, Hossein Nejadi Koti

Dissertations (1934 -)

The goal of this dissertation is to establish computationally efficient large-scale design optimization procedures for induction motors that are not only computationally efficient, but also do not sacrifice the accuracy of the results. To achieve this goal, the topic of the lengthy numerical transient response of Time-Stepping Finite Element Analysis (TS-FEA) of induction motors was investigated. This is because this lengthy transient affects the computational efficiency aspect of the optimization process. The effect of different parameters on the numerical transient response phenomenon were studied, and two different techniques for mitigation of this numerical transient were evaluated. The superior one amongst …

Vibration Control Of A Two-Story Base-Isolated Building Using A New Tuned Mass Multi-Sliding Friction Damper, Mohsen Amjadian, Syed Muhammad Bilal Haider

Civil Engineering Faculty Publications

This paper studies the use of a new Tuned Mass Multi-Sliding Friction Damper (TMMSFD) to increase the damping capacity of seismic isolators installed on a two-story base-isolated building to limit their lateral deformations. The proposed TMMSFD consists of a set of several masses that are laterally attached to the superstructure floor through linear springs. These masses are placed on top of each other one by one and are allowed to slide with respect to each other during the earthquake. The bottom mass that carries the weight of upper masses is in contact with the superstructure floor. The damping of system …

A Device For Measuring Acoustic Output Intensity Of Transcranial Doppler Ultrasound Transducers For Comparison With Fda Regulations, Sarah Altman, Gregory Bashford, Benjamin Hage

Honors Program: Senior Projects (Public)

Transcranial Doppler Ultrasonography (TCD) is a non-invasive methodology which can evaluate cerebral blood flow velocity in real time. Single-element focused circular transducers placed on the scalp produce ultrasound waves capable of penetrating the skull with minimal aberration, enabling measurement of the Doppler shift. As such, TCD can measure blood flow velocity in the internal carotid and vertebral arteries, as well as the arteries of the Circle of Willis: the Anterior Cerebral (ACA), Posterior Cerebral (PCA), and Middle Cerebral Arteries (MCA). Intracranial aneurysm and ischemic stroke are serious conditions in which ballooning or occlusion of cerebral vessels cause insufficient perfusion, leading …

The Photochemical Evolution Of Polycyclic Aromatic Hydrocarbons And Nontronite Clay On Early Earth And Mars, Nina Kopacz, Maria Angela Corazzi, Giovanni Poggiali, Ayla Von Essen, Vincent Kofman, Teresa Fornaro, Hugo Van Ingen, Eloi Camprubi, Helen E. King, John Brucato, Inge Loes Ten Kate

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

The photochemical evolution of polycyclic aromatic hydrocarbons (PAHs), an abundant form of meteoritic organic carbon, is of great interest to early Earth and Mars origin-of-life studies and current organic molecule detection efforts on Mars. Fe-rich clay environments were abundant on early Earth and Mars, and may have played a role in prebiotic chemistry, catalyzing the breakdown of PAHs and freeing up carbon for subsequent chemical complexification. Current Mars is abundant in clay-rich environments, which are most promising for harboring organic molecules and have comprised the main studied features by the Curiosity rover in search of them. In this work …

An Investigation Into The Economic Useful Life Of Commercial Aircraft As Impacted By Maintenance And Economic Variables, Robert Gallagher

Doctoral Dissertations and Master's Theses

This research involved examining the economic useful life of commercial aircraft and the impact of maintenance and economic variables on the viability and longevity of the asset. The data sample consisted of the entire population of Boeing commercial aircraft produced between 1956 and 2021. The objective was to determine the effect of both maintenance and economic variables on the longevity and usefulness of commercial aircraft. As manufacturers work with issues such as service life, economic life, safety, and critical design features, those in the aviation community focus on the operational side of the equation––how long can one operate the asset, …

Prediction & Active Control Of Multi-Rotor Noise, Samuel O. Afari

Doctoral Dissertations and Master's Theses

Significant developments have been made in designing and implementation of Advanced Air Mobility Vehicles (AAMV). However, wider applications in urban areas require addressing several challenges, such as safety and quietness. These vehicles differ from conventional helicopter in that they operate at a relatively lower Reynolds number. More chiefly, they operate with multiples of rotors, which may pose some issues aerodynamically, as well as acoustically. The aim of this research is to first investigate the various noise sources in multi-rotor systems. High-fidelity simulations of two in-line counter-rotating propellers in hover, and in forward flight conditions are performed. Near field flow and …

Autonomous Space Surveillance For Arbitrary Domains, David Zuehlke

Doctoral Dissertations and Master's Theses

Space is becoming increasingly congested every day and the task of accurately tracking satellites is paramount for the continued safe operation of both manned and unmanned space missions. In addition to new spacecraft launches, satellite break-up events and collisions generate large amounts of orbital debris dramatically increasing the number of orbiting objects with each such event. In order to prevent collisions and protect both life and property in orbit, accurate knowledge of the position of orbiting objects is necessary. Space Domain Awareness (SDA) used interchangeably with Space Situational Awareness (SSA), are the names given to the daunting task of tracking …

Development Of A Metal Droplet Generator For Studying Impact Dynamics, Xitong Xu

McKelvey School of Engineering Graduate Student Theses & Dissertations

Metal droplet-based 3D printing is a popular technique used for creating complex structures and multi-material components. However, accuracy is a significant challenge in this process due to complex thermal and dynamic behaviors that can negatively affect the final workpiece. To improve accuracy, the interactions between droplet impact dynamics and the deposition process of the droplets must be understood and ultimately controlled. In this thesis, I describe the optimization and implementation of an experimental setup for generating droplets of tin and for studying their impact dynamics. In particular, this thesis explains how an existing preliminary droplet generator was modified to produce …

A Survey Of Text Representation And Embedding Techniques In Nlp, Rajvardhan Patil, Sorio Boit, Venkat Gudivada, Jagadeesh Nandigam

Open Access Publishing Support Funded Articles

Natural Language Processing (NLP) is a research field where a language in consideration is processed to understand its syntactic, semantic, and sentimental aspects. The advancement in the NLP area has helped solve problems in the domains such as Neural Machine Translation, Name Entity Recognition, Sentiment Analysis, and Chatbots, to name a few. The topic of NLP broadly consists of two main parts: the representation of the input text (raw data) into numerical format (vectors or matrix) and the design of models for processing the numerical data. This paper focuses on the former part and surveys how the NLP field has …

Large Eddy Simulation For Empirical Modeling Of The Wake Of Three Urban Air Mobility Vehicles, Denis-Gabriel Caprace, Andrew Ning

Faculty Publications

Recent advances in urban air mobility have driven the development of many new VTOL concepts. These vehicles often feature original designs departing from the conventional helicopter configuration. Due to their novelty, the characteristics of the super-vortices forming in the wake of such aircraft are unknown. However, these vortices may endanger any other vehicle evolving in their close proximity, owing to potentially large induced velocities. Therefore, improved knowledge about the wakes of VTOL vehicles is needed to guarantee safe urban air mobility operations. In this work, we study the wake of three VTOL aircraft in cruise by means of large eddy …

Measuring Radiation Protection: Partners From Across The Nuclear Enterprise Evaluate The Radiation Protection Of Us Army Vehicles, Andrew W. Decker, Robert Prins

Faculty Publications

Recent mounting nuclear threats and postures from adversary nation-states, such as Russia, China, North Korea, and Iran, represent a clear danger to the interests and security of the United States of America and its Allies. To meet these threats, the 2022 Nuclear Posture Review requires the Department of Defense (DoD) to design, develop, and manage a combat-credible U.S. military which, among other prioritizations, is survivable. A survivable force can generate combat power despite adversary attacks. As such, the US Army must prepare today to set the conditions for successful conventional warfare on the nuclear battlefields of tomorrow. Our Army cannot …

Law Informs Code: A Legal Informatics Approach To Aligning Artificial Intelligence With Humans, John J. Nay

Northwestern Journal of Technology and Intellectual Property

Artificial Intelligence (AI) capabilities are rapidly advancing. Highly capable AI could cause radically different futures depending on how it is developed and deployed. We are unable to specify human goals and societal values in a way that reliably directs AI behavior. Specifying the desirability (value) of AI taking a particular action in a particular state of the world is unwieldy beyond a very limited set of state-action-values. The purpose of machine learning is to train on a subset of states and have the resulting agent generalize an ability to choose high value actions in unencountered circumstances. Inevitably, the function ascribing …

Camera-Radar Sensor Fusion For Depth Estimation, Lonnie D. Chien , '23

Senior Theses, Projects, and Awards

Self-driving cars rely on sensors for their perception of the surrounding environment. Depth estimation provides crucial information for the control systems of autonomous vehicles, as avoiding collisions and accidents is impossible without knowledge of the 3-dimensional locations of other objects on the road. Monocular depth estimation, or depth estimation from a single camera, shows promise as a relatively inexpensive yet effective solution to the depth estimation task. Cameras, however, are limited by the image formation process in their ability to calculate 3-dimensional depth from 2-dimensional images. Traditional machine-learning models use images paired with ground-truth depth labels for training. The image-label …

Method Design For Separation Of Non-Canonical Dna Structures Via Capillary Electrophoresis, Erin V. Chen , '23

Senior Theses, Projects, and Awards

G-quadruplex DNA structures are highly relevant subjects of biochemical study, implicated in human diseases and cancer. Conventional methods for G-quadruplex DNA structure separation are time-consuming, environmentally unfriendly, and low throughput. Thus, there is a pressing need for alternative methods of separation to be developed for G-quadruplex DNAs. Here we present work in designing a separation method using the capillary electrophoresis instrument. Capillary electrophoresis is a highly automated, reusable, and quantitative technique that separates analytes based on their size and charge. A capillary method for G-quadruplex separation would be a valuable analytical tool to supplement the biophysical methods available by addressing …

The Potential For Mycofiltration Of E. Coli Pollution In The Crum Creek Using T. Versicolor And P. Ostreatus, Kennedy M. Hill , '23

Senior Theses, Projects, and Awards

Mycoremediation is a cost-effective and environmentally friendly alternative to conventional wastewater and drinking water treatment, as well as other environmental remediation methods. This project will design a mycofiltration system using mushroom species T. versicolor and P. ostreatus. Water from a section of the Crum Creek, located in Swarthmore, Pennsylvania, U.S.A, will be sampled and filtered through this system to remove Escherichia coli (E. coli). The mycofiltered water will be compared to the Environmental Protection Agency standards for E. coli concentrations in recreational and drinking water to measure how effective T. versicolor or P. ostreatus may be at removing …

Swimming Robots Using Memory Metal, Joshua R. Heckman , '23

Senior Theses, Projects, and Awards

While in the very early stages of life, Barnacle nauplii are only a few micrometers in length, which causes them to experience a very low Reynolds number while swimming through water. It is important to understand how these biological creatures swim, so their movements can be mimicked and incorporated into robotics. Currently, there are no autonomous underwater vehicles (AUV) that are capable of carrying out missions in fluids with low Reynolds numbers. This project aimed to replicate the movement of a Barnacle Napuli with the use of muscle memory wire, in hopes that one day a AUV that can operate …

Model For Movement Classification Of The Bicep, Youssef Kharrat , '23

Senior Theses, Projects, and Awards

This project introduces a classification model whose purpose is the distinction between the two possible movements done by the bicep; namely flexion and rotation. Surface EMG data was collected using the MIKROE-2621. It was later sampled from Analog to Digital by a Nucleo 401-RE board at 200 Hz. To generate the dataset, I connected the apparatus to my arm and performed the movements a total number of 300 times. This data was later analyzed and a choice of features were made that eventually was fed into MATLAB Classification Learner. A Support Vector Machine performed best and was able to classify …

Capabilities Of Conductive Thread Twisted-And-Coiled Actuators As Sarcomeres, Bryan T. Le , '23

Senior Theses, Projects, and Awards

Twisted-and-coiled actuators (TCAs) have shown great potential as an artificial muscle for robotics in terms of material cost and production expenses. However, the power-to-force efficiency of these artificial muscles falls short of biological muscles. Soft robotics takes inspiration from biological organisms for more natural movement, and biological mimicry helps increase the efficiency of robotics. Taking inspiration from how sarcomeres are structured in natural muscles, improvements in the energy efficiency of artificial muscles are possible. In this paper, an experiment was designed to analyze the effects on the efficiency of emulating biological sarcomere structures in artificial muscles. Specifically, this experiment used …