Engineering Commons^™

Robust Predictive Analytics For Determining Acclimation Parameter Of It Equipment, Premsanth Sadasivam

Mechanical and Aerospace Engineering Theses - Archive

Acclimation is the process in which an IT equipment adjusts to a change in its environment such as a change in temperature and humidity, allowing it to maintain performance across a range of environmental conditions. In commissioning of a new cold shipped IT equipment in data centers, environmental acclimation is an important step. Proper acclimation also minimizes the risk of powering on a machine that may still be wet due to moisture condensation. An experimental study is carried out to find how the acclimation occurs and the factors influencing it. These experiments are designed with various temperature ranges and using …

Seismic Forces In Ancillary Components Supported On Piers And Wharves, Rakesh K. Goel

Civil and Environmental Engineering

This paper presents a simple procedure to estimate seismic forces in ancillary components (secondary systems) supported on marine structures such as piers, wharves, and marine oil terminals (primary systems). Since many such marine structures can be idealized as single-degree-of-freedom (SDOF) systems, this study uses a simple linear-elastic model with two DOF, one representing the marine structure and the other representing the ancillary component. This study shows that acceleration at the base of the secondary system is approximately equal to spectral acceleration at the fundamental period of the primary system. It also proposes a formula, which is an improvement over current …

An Agent Based Model To Assess Crew Temporal Variability During U.S. Navy Shipboard Operations, Kevin Muhs

Electronic Theses and Dissertations

Understanding the factors that affect human performance variability as well as their temporal impacts is an essential element in fully integrating and designing complex, adaptive environments. This understanding is particularly necessary for high stakes, time-critical routines such as those performed during nuclear reactor, air traffic control, and military operations. Over the last three decades significant efforts have emerged to demonstrate and apply a host of techniques to include Discrete Event Simulation, Bayesian Belief Networks, Neural Networks, and a multitude of existing software applications to provide relevant assessments of human task performance and temporal variability. The objective of this research was …

Handwritten Digit Recognition By Multi-Class Support Vector Machines, Yu Wang

Graduate Theses/Dissertations

Support Vector Machine(SVM) is a widely-used tool for pattern classification problems. The main idea behind SVM is to separate two different groups with a hyperplane which makes the margin of these two groups maximized. It doesn't require any knowledge about the object we are focused on, since it can catch the features automatically. The idea of SVM can be easily generalized to nonlinear model by a mapping from the original space to a high-dimensional feature space, and they construct a max-margin linear classifier in the high dimensional feature space.

This thesis will investigate the basic idea of SVM and apply …

Magnetic Studies Of Multiferroic Heterostructures, Ahmed Rayhan Mahbub

Graduate Theses/Dissertations

Multiferroic heterostructures (MHS) consisting of at least two materials with ferroic properties have been a major focus for researchers recently due to its immense potential in device applications. Almost all MHS use ferromagnetic layers making it a very important research area. In this thesis the magnetic properties of different ferromagnetic heterostructures have been investigated. Different bilayers of hard ferromagnet cobalt ferrite (CFO)-soft ferromagnet lanthanum strontium manganese oxide (LSMO) and hard ferromagnet CFO-antiferromagnet nickel oxide (NiO) were fabricated. Pulsed laser deposition technique was used to deposit the thin films on LAO and sapphire substrates. Purpose of using a hard ferromagnetic CFO …

Design, Fabrication, And Characterization Of Novel Optoelectronic Devices For Near-Infrared Detection, Ahmad Nusir

Graduate Theses and Dissertations

Investigating semiconductor materials and devices at the nanoscale has become crucial in order to maintain the exponential development in today’s technology. There is a critical need for making devices lower in power consumption and smaller in size. Nanoscale semiconductor materials provide a powerful platform for optoelectronic device engineers. They own interesting properties which include enhanced photoconductivity and size-tunable interband transitions.

In this research, different types of nanostructures were investigated for optoelectronic devices: nanocrystals, nanowires, and thin-films. First, lead selenide nanocrystals with narrow bandgap were synthesized, size-tailored, and functionalized with molecular ligands for the application of uncooled near-infrared photodetectors. The devices …

Experimental And Model-Based Terahertz Imaging And Spectroscopy For Mice, Human, And Phantom Breast Cancer Tissues, Tyler Bowman

Graduate Theses and Dissertations

The goal of this work is to investigate terahertz technology for assessing the surgical margins of breast tumors through electromagnetic modeling and terahertz experiments. The measurements were conducted using a pulsed terahertz system that provides time and frequency domain signals. Three types of breast tissues were investigated in this work. The first was formalin-fixed, paraffin-embedded tissues from human infiltrating ductal and lobular carcinomas. The second was human tumors excised within 24-hours of lumpectomy or mastectomy surgeries. The third was xenograft and transgenic mice breast cancer tumors grown in a controlled laboratory environment to achieve more data for statistical analysis.

Experimental …

Development Of Microdialysis Probes In Series Approach Toward Eliminating Microdialysis Sampling Calibration: Miniaturization Into A Pdms Microfluidic Device, Randy Espinal Cabrera

Graduate Theses and Dissertations

A new microdialysis sampling method and microfluidic device were developed in vitro. The method consisted of using up to four microdialysis sampling probes connected in series to evaluate the relative recovery (RR) of different model solutes methyl orange, fluorescein isothiocyanate (FITC)-dextran average mol. wt. 4,000 (FITC-4), FITC-10, FITC-20, and FITC-40. Different flow rates (0.8, 1.0, and 1.5 µL/min) were used to compare experimentally observed relative recoveries with theoretical estimations. With increasing the number of probes in series, the relative recovery increases and ~100% (99.7% ± 0.9%) relative recovery for methyl orange was obtained. For larger molecules such as fluorescein isothiocyanate …

Glucose Level Estimation Based On Invasive Electrochemical, And Non-Invasive Optical Sensing Methods, Sanghamitra Mandal

Graduate Theses and Dissertations

The purpose of this research is to design and fabricate sensors for glucose detection using inexpensive approaches. My first research approach is the fabrication of an amperometric electrochemical glucose sensor, by exploiting the optical properties of semiconductors and structural properties of nanostructures, to enhance the sensor sensitivity and response time. Enzymatic electrochemical sensors are fabricated using two different mechanisms: (1) the low-temperature hydrothermal synthesis of zinc oxide nanorods, and (2) the rapid metal-assisted chemical etching of silicon (Si) to synthesize Si nanowires. The concept of gold nano-electrode ensembles is then employed to the sensors in order to boost the current …

Developing A Hil-Based Software Platform For Testing Electric And Hybrid Vehicle Powertrains, Daniel Schwartz

Graduate Theses and Dissertations

The objective of this thesis is to present a dynamometer test stand with hardware in the loop (HIL) testing capabilities for the evaluation of electric and hybrid vehicle powertrains under realistic driving conditions. The traction inverter and dc/dc converter are two crucial subsystems of the powertrain and new prototypes require significant validation before implementing into production vehicles. As fundamental technologies such as power modules, thermal management systems, and passive components improve; the performance improvements to the overall system must be demonstrated. The plug and play nature of the testbed makes it ideal for making direct comparisons of design iterations under …

Design, Fabrication, And Characterization Of All-Inorganic Quantum Dot Light Emitting Diodes, Ramesh Vasan

Graduate Theses and Dissertations

Quantum dot light emitting diodes are investigated as a replacement to the existing organic light emitting diodes that are commonly used for thin film lighting and display applications. In this, all-inorganic quantum dot light emitting diodes with inorganic quantum dot emissive layer and inorganic charge transport layers are designed, fabricated, and characterized. Inorganic materials are more environmentally stable and can handle higher current densities than organic materials. The device consists of CdSe/ZnS alloyed core/shell quantum dots as the emissive layer and metal oxide charge transport layer. The charge transport in these devices is found to occur through resonant energy transfer …

Investigation Of Nanomaterial Based Photovoltaic Panel Packaging Materials, Xingeng Yang

Graduate Theses and Dissertations

In this research, nanomaterial-based packaging materials for photovoltaic (PV) panels are investigated. A hydrophobic/anti-reflective surface coating which not only repels water from the top glass of a PV panel but at the same time reduces its light reflectance is investigated. COMSOL simulation results indicate that taller ellipsoid rod (aspect ratio = 5) reflects less light than shorter rod (aspect ratio = 0.5) in the desired spectrum for solar energy harvest from 400nm-700nm. The addition of a polymer layer on these ellipsoid rods broadens the light incident angle from 23° to 34°, from which light can be efficiently absorbed. Based on …

Application Of Modular Multilevel Converters (Mmc) Using Phase-Shifted Pwm And Selective Harmonic Elimination In Distribution Systems, Thouhidul Islam

Graduate Theses and Dissertations

Reducing the size and weight of a power electric system is a prodigious challenge to researchers as the development of the latest technologies emerge in the field of electrical engineering. A similar urge is there to develop a light-weight mobile power substation (MPS) to use in the electric power distribution systems during emergency conditions. This thesis proposes a power electronics based solution using the modular multilevel converter (MMC) topology to design the MPS system. The market-available power semiconductor devices are analyzed and suitable devices are selected to design the system. The phase-shifted pulse width modulation (PS-PWM) and selective harmonic elimination …

Structure And Property Of Polymers And Biopolymers From Molecular Dynamic Simulations, Xiaoquan Sun

Graduate Theses and Dissertations

Natural and synthetic polymers and biopolymers have been studied for a variety of applications in food emulsion, biopharmaceutical purification, tissue engineering, and biosensor. The structure and property of polymers and biopolymers are critically important to determine their functions. Molecular dynamics (MD) simulations have a unique advantage to explore the structure and property of polymers and biopolymers from the molecular level. In the dissertation, MD simulations were conducted to study the mechanisms of various biological and chemical processes controlled by polymers and biopolymers based on real-world experimental results.

Seven heptapeptides have been screened from a peptide library in our earlier study …

Evaluation Of Terahertz Imaging For Breast Cancer Detection Using Image Morphing, Tanny Andrea Chavez Esparza

Graduate Theses and Dissertations

This thesis proposes the use of a mesh morphing algorithm for the quantitative evaluation of terahertz (THz) images. This work differs from traditional evaluation methods based on qualitative evaluation because it provides a fair and quantitative measurement of the THz imaging system's performance. The objective of the algorithm is to match the alignment, shape, and resolution of the THz and reference pathology images. Therefore, the proposed morphing method provides a pathology reference for a pixel-by-pixel evaluation of the region classification in the THz image. To achieve this, the morphing algorithm aligns the images using the Pearson's correlation coefficient and reshapes …

The Incorporation Of Graphene To Lithium Cobalt Oxide As A Cathode To Improve The Performance Of Lithium Ion Batteries, Kenan Wang

Graduate Theses and Dissertations

One of the objectives of this thesis work was to investigate the cathode performance of lithium cobalt oxide (LiCoO2) incorporated with graphene powder in lithium ion batteries (LIBs). Graphene powder was incorporated into cathode materials to enhance the performance of LIBs. The other objective was to impede the construction of a solid electrolyte interphase (SEI) sheet using graphene sheet coating on its cathode.

The results of this work show that adding graphene powder improved the performance of LiCoO¬2 as a cathode material. With the incorporation of different weight percentages of graphene powder, the LiBs showed distinct changes in their charging …

Self-Assembled Barium Titanate Nanoscale Films By Molecular Beam Epitaxy, Timothy Allen Morgan

Graduate Theses and Dissertations

One challenge of investigating ferroelectrics at the nanoscale has been controlling the stoichiometry during growth. Historically, the growth of barium titanate (BaTiO3) by molecular beam epitaxy has relied on a growth technique called shuttered RHEED. Shuttered RHEED controls the stoichiometry of barium titanate through the precise deposition of alternating layers of BaO and TiO2. While this approach has achieved 1% control of stoichiometry, finding self-limiting mechanisms to lock-in stoichiometry has been the focus of the growth community. The Goldschmidt tolerance factor predicts an unstable perovskite when barium sits in the titanium lattice site. The BaO-TiO2 phase diagram predicts a low-solubility …

Breathing-Based Authentication On Resource-Constrained Iot Devices Using Recurrent Neural Networks, Jagmohan Chauhan, Suranga Seneviratne, Yining Hu, Archan Misra, Aruna Seneviratne, Youngki Lee

Research Collection School Of Computing and Information Systems

Recurrent neural networks (RNNs) have shown promising resultsin audio and speech-processing applications. The increasingpopularity of Internet of Things (IoT) devices makes a strongcase for implementing RNN-based inferences for applicationssuch as acoustics-based authentication and voice commandsfor smart homes. However, the feasibility and performance ofthese inferences on resource-constrained devices remain largelyunexplored. The authors compare traditional machine-learningmodels with deep-learning RNN models for an end-to-endauthentication system based on breathing acoustics.

Evaluating The Impact Of External Carbon Source In Laboratory-Based Denitrification Rate Experiments, Jared Richens

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Limitations in the quality of transformation rates used with water quality models such as QUAL2K have led to the need to identify methods that can effectively and accurately determine these rates. During the early stages of method development of a Utah Department of Environmental Quality (Utah DEQ) funded project seeking to identify such methods, it was determined that under certain situations external carbon amendment may be required to successfully determine denitrification rates.

The focus of this study was to evaluate the potential impacts that introducing external carbon sources may have on estimating the laboratory denitrification rates resulting from these methods. …

Size-Scale Effects Of Nonlinear Weir Hydraulics, Nathan L. Young

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Experimental physical model studies of hydraulic structures are often conducted to replicate flow behavior that may occur at the prototype scale. Geometric similitude is most often maintained between the prototype and model when studying reservoir and open channel hydraulic structures to account for the dominant gravity and inertia forces while other fluid forces (e.g., viscosity,surface tension) are assumed negligible. However, as model size and/or upstream head decreases, other fluid forces can exceed the negligible level and influence model flow behavior. This phenomenon is referred to as size-scale effects and is one potential origin of error in predicting the prototype behavior …

Simulation And Optimization Models To Evaluate Performance Of Aquifer Storage And Recovery Wells In Fresh Water Aquifers, Ali Forghani

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Aquifer storage and recovery (ASR) involves artificially recharging an aquifer through well(s) using surplus water for later recovery in high-demand months. The operators of the studied ASR system developed the system as a means of receiving additional water rights to supplement their pre-existing water rights for extraction in dry months. However, the region’s water regulators define the performance of this ASR system as the amount of the injected water that is recoverable from the same wells during extraction periods. The study proposes recovery effectiveness (REN) as the performance index of this ASR system. REN equals the injectate proportion that the …

Direct Potable Reuse Of Wastewater, Molly Churchwell

Chemical Engineering Undergraduate Honors Theses

Water is essential to our societies and mankind. Currently, 844 million people across the globe lack access to potable water. By 2025, it is projected that half of the world population will be in a region of water stress.5 The water crisis is often thought of as a problem limited to places that have always struggled to have clean water, but it is now affecting new areas such as the southwest United States. With increasing population demands and drought, the feasibility of direct potable reuse (DPR) of wastewater is being considered. According to an EPA report in 2017, there are …

Removal Of Carbamazepine From Drinking Water, Zachary Wiese

Chemical Engineering Undergraduate Honors Theses

Due to the increasing prevalence of prescription medication over the past few

decades, pharmaceuticals have accumulated in various water sources. This has become a

public health concern because many pharmaceuticals have limited research on the effects

of chronic low-level exposure. According to the World’s Health Organization (WHO),

traces of pharmaceuticals products have been reported in different water sources such as

surface waters, wastewater, groundwater, and drinking water.[1] One pharmaceutical of

interest that has been detected in water sources is carbamazepine. Carbamazepine is a

common pharmaceutical prescribed for the treatment of seizure disorders, neuropathic

pain, and various psychological disorders. It’s mechanism …

Secure Aircraft Maintenance Records Using Blockchain (Samr), Ahrash Aleshi

Doctoral Dissertations and Master's Theses

We propose to enhance the security and transparency of aircraft maintenance records in the aviation industry through the use of blockchain technology. A physical aircraft maintenance logbook is susceptible to being lost or destroyed. A nonexistent aircraft maintenance logbook hurts the confidence in integrity and reputation of the aircraft. Furthermore, fraud can occur through forgery of FAA personnel signatures and the installation of non-official aircraft parts. The scope of this work is to develop a secure blockchain that can store aircraft service records and information in a digital distributed ledger. By keeping the maintenance logbook on a digital ledger, records …

A Novel Magnetorheological Fluid Damper For A Small Spacecraft With Flexible Appendages, Robert Waelchli

Doctoral Dissertations and Master's Theses

Small satellites have become increasingly popular over the past thirty years, particularly since the adoption of the common CubeSat architecture early this century. Because of their restricted volume and electrical budgets however, there are practical limits to the missions that small satellites may adopt. One potential near-term solution to the problem of limited electrical power may be the adoption of larger, flexible solar arrays. However, spacecraft with flexible appendages have historically presented attitude control challenges relating to platform stability given the dynamic response of the flexible components to applied torques. These challenges may be particularly disruptive to a small spacecraft …

Propulsive Battery Packs Sizing For Aviation Applications, Tianyuan Zhao

Doctoral Dissertations and Master's Theses

This thesis derives analytical methods for sizing the propulsive battery packs for designing an electric-driven aircraft. Lithium-Ion (Li-Ion) battery is the primary choice of battery cell chemistry in this thesis research due to its superior specific energy and market availability. The characteristics of Lithium-Ion battery cells are first determined and studied using experimental test results and manufacturers published data. Based on the design requirement to the battery system, the battery sizing will fall into one of the two sizing categories. The first category is power sizing, which requires the battery’s ability to deliver full power demanded by the electric motor. …

Development Of A Small Unmanned Aerial Vehicle Longitudinal Model For Future Flutter Testing, Said S. Hamada

Doctoral Dissertations and Master's Theses

This thesis presents the system identification of the longitudinal motion of a small unmanned aerial vehicle with flexible characteristics. The unmanned aerial vehicle of study is an off-the-shelf aircraft with limited knowledge about the dynamic model. The first task in obtaining a model for flutter testing is determining the rigid body model. Specifically, this thesis will focus in the development of the aircraft and obtaining the longitudinal rigid body model. This involves the assembly and configuration of the avionics and sensors, performing experiments to determine mass and inertia properties and using software tools for aerodynamic analysis to get preliminary values …

An Alternative Method Of Identification Of A Failed Engine In Twin-Engine Propeller Aircraft, Andrey Babin

Doctoral Dissertations and Master's Theses

Previous research has revealed that wrong identification of a failed engine during flight is not an uncommon event in an aircraft cockpit. A number of fatal accidents in the past, including the recent TransAsia Flight 235 accident, resulted from engine misidentification. Most accidents of this type happened on takeoff when pilot workload was at its highest level. This thesis consists of two research studies. For Research Study 1, a survey was created to gather opinions of airline pilots who operate twin-engine turboprop aircraft. Twenty-nine percent of respondents to the survey agreed with the statement that there could be a better …

Vision-Aided Navigation Using Tracked Landmarks, Nicodemus Myhre

Doctoral Dissertations and Master's Theses

This thesis presents vision-based state estimation algorithms for autonomous vehicles to navigate within GPS-denied environments. To accomplish this objective, an approach is developed that utilizes a priori information about the environment. In particular, the algorithm leverages recognizable ‘landmarks’ in the environment, the positions of which are known in advance, to stabilize the state estimate. Measurements of the position of one or more landmarks in the image plane of a monocular camera are then filtered using an extended Kalman filter (EKF) with data from a traditional inertial measurement unit (IMU) consisting of accelerometers and rate gyros to produce the state estimate. …

Homography-Based State Estimation For Autonomous Exploration In Unknown Environments, Andres S. Chavez Armijos

Doctoral Dissertations and Master's Theses

This thesis presents the development of vision-based state estimation algorithms to enable a quadcopter UAV to navigate and explore a previously unknown GPS denied environment. These state estimation algorithms are based on tracked Speeded-Up Robust Features (SURF) points and the homography relationship that relates the camera motion to the locations of tracked planar feature points in the image plane. An extended Kalman filter implementation is developed to perform sensor fusion using measurements from an onboard inertial measurement unit (accelerometers and rate gyros) with vision-based measurements derived from the homography relationship. Therefore, the measurement update in the filter requires the processing …