Engineering Commons^™

Directed Energy Deposition Processing-Performance Relationship Of Af9628, Mianqing Yang

Masters Theses

"AF9628 low alloy steel is a novel steel known for its low cost, high hardness, and outstanding tensile performance. However, the processing methods of AF9628 have been less studied in the additive manufacturing field. As the balance of hardness and tensile results is closely related to the cooling process during manufacturing process window and its relationship to resultant tensile properties is explored. By using the DED method, specimens of this steel are successfully fabricated, and tensile test results are obtained. The AF9628 steel can be manufactured for tailored properties with the DED process by controlling the cooling method. This work …

High-Pressure Infiltration Process For Additively Manufactured Ceramic Matrix Composites, Samuel Weiler

Masters Theses

"Ceramic matrix composites were developed in order to increase the fracture toughness, thermal shock resistance, and elongation of ceramic materials, while maintaining the very high temperature capabilities of these materials. A renewed focus has been placed on ceramic matrix composites due to the need for materials that maintain good mechanical strength at very high temperatures, for use in the extreme environments encountered by hypersonic vehicles, jet turbine blades, and the like. However, conventional methods to manufacture CMCs are costly and time consuming. The aim of this work is to develop a method for creating additively manufactured ceramic matrix composites using …

Low Finesse Extrinsic Fabry-Perot Interferometer (Efpi) Demodulation For High Temperature Gap Measurements, Abhishek Prakash Hungund

Masters Theses

"In continuous casting steel industries, mold flux is added to provide thermal and chemical insulation for molten steel. The mold flux absorbs detrimental inclusions from the steel and promotes uniform heat distribution to prevent sticking. To promote flux infiltration, mold oscillation is used, but this creates oscillation marks that reduce local shell growth and increase temperatures. Wide (2-3 mm) and deep (0.5-0.9 mm) oscillation marks with areas of 1.1-2.5 mm² are observed, affecting the steel quality, which results in a loss of 6% per billet to the industry. To address this challenge, we propose an extrinsic Fabry-Perot interferometer (EFPI) sensor …

Laboratory Scale Experimental Analysis Of The Effect Of Surfactants On Acid Mist Suppression During Copper Electrowinning, Thurman Kollie Elgin

Masters Theses

"The reduction in acid mist generation is an industrial occupational objective in the electrowinning industry of base metals. The technology of electrowinning as an extractive metallurgical technique of metals proficiently contributed to the recovery of pure base metals. During the process of electrowinning, oxygen bubbles are generated on the anode of the electrowinning cell because of the over potential in the cell due to high voltage. The bubbles formed tend to contain sulfuric acid of the electrolyte in the form of liquid-gas ascending particles of the solution. As these bubbles ascend to the surface of the solution, they burst at …

Processing & Properties Of Zirconium Carbide Manufactured By Ceramic On-Demand Extrusion, Clare Sabata

Masters Theses

"This research focuses on the development of a zirconium carbide (ZrC) paste for use in material extrusion direct ink write additive manufacturing (AM) followed by the pressure less densification of ZrC and the mechanical and thermal characterization of the resulting ceramics. A highly loaded, aqueous paste was developed using commercial ZrC powder ball milled to ~1 μm. Optimal dispersant, binder, and solids loading were found by rheological characterization. The paste composition consisted of 46-47 vol% ZrC, 43.5 vol% distilled water, 8.1 vol% dispersant, and 1.6 vol% binder. A yield stress of ~8 Pa allowed for shape retention upon removal of …

Microwave Materials Characterization Of Geopolymers, Jared Sinkey

Masters Theses

"The purpose of this work was to develop a process for studying geopolymer materials using a microwave materials characterization approach. Such an approach is known to provide information about chemical and physical properties of materials. As such, in this work, the focus is on the role of water in the geopolymer curing process. To do this, specimens were prepared and cast and microwave measurements conducted throughout the curing process using a short-circuited rectangular waveguide (SC-RWG) measurement technique. In this technique, the complex reflection properties/coefficient of the sample are measured. The effect of sample length and dielectric properties on materials characterization …

Investigating Accident-Tolerant Cladding In A Molten Salt-Cooled Micro-Reactor Using Multi-Physics Analysis And Uncertainty Quantification, Alexander Niles Foutch

Masters Theses

"Renewed interest in nuclear safety has resulted in development of accident-tolerant materials, such as cladding. Although developed for light water reactors, their use in more advanced reactors would save time and development costs for other new materials. This paper performed a Multiphysics investigation into the power profile, thermodynamics, heat transfer, and tensor mechanics of four candidate materials (Haynes 230, Zircaloy-4, FeCrAl, and SiC-SiC), using the highly benchmarked Kilo power design as an example of a high-temperature, highly enriched, sodium-cooled microreactor environment.

From neutronic code MCNP, no significant difference in power profile was found among the four. Using finite element software …

Discrete Event Simulation (Des) In Swapping/Charging Of Battery Electric Vehicles In Underground Mining, Albert Einstein Amponsem

Masters Theses

"With climate change concerns escalating, international agreements such as the Kyoto Protocol, the US Presidential Policy, and the Paris Agreement aim to reduce greenhouse gas (GHG) emissions, targeting significant reductions by 2050. The mining sector, a notable contributor to GHG emissions primarily through diesel-powered material haulage, emits approximately 68 million tons of CO₂ annually. Transitioning to Battery Electric Trucks (BETs) presents a viable mitigation strategy by replacing diesel trucks with electric alternatives, thus eliminating CO₂ emissions.

However, the effectiveness of BETs hinges on optimized battery swapping and charging procedures. This study employs Discrete Event Simulation (DES), a computational …

Development Of A Particulate Matter Sensor Network For Air Quality Monitoring In Indoor Settings And In Mines, Abdulrahman Bani

Masters Theses

"The importance of indoor air quality (IAQ), especially concerning particulate matter (PM), has become increasingly recognized due to its substantial impact on public health. Individuals spend a significant portion of their time indoors, where PM concentrations can exceed that of outdoors, leading to potential adverse health effects ranging from immediate irritation to long-term respiratory and cardiovascular diseases. The dynamic nature of indoor environments, combined with the diversity of PM sources, presents considerable challenges for effective IAQ monitoring and management. Traditional approaches to IAQ assessment often fall short, lacking the granularity and immediacy required to address these challenges adequately.

This abstract …

The Graduation Walk: Pareto Optimization Of Degree Paths, Arianna Gail Sy Chaves

Masters Theses

"A student’s academic history, course availability at their institution, and the overall degree of difficulty of the schedule for each semester are all critical factors in their academic success and experience. This thesis proposes an advanced recommendation algorithm that considers these real and conflicting factors that are involved in identifying a prudent degree path - a semester-by-semester course schedule to graduation - for each student. The original contribution of this work is the use of weighted-sum multi-objective constraint programming to minimize an increased number of optimization criteria and identify Pareto-optimal degree paths to be recommended to the student. The conflicting …

Evaluating Electromagnetic Interference On Gnss Receivers, Giorgi Tsintsadze

Masters Theses

"Due to high power and efficiency requirements of modern electrical drive system, inverters are utilizing fast-edge pulses as a drive signal. The high frequency pulses contain higher order harmonics can radiate electromagnetic interference above accepted levels. Modelling and understanding the mechanism that causes the radiation is studied, modelled and presented as gray-box model which contains circuit level modelling of coupling between electrical machine phase windings and low power sensor harness. The thesis consists of two main papers. In the first paper, radiated emissions from an electrical drive system is charac- terized thru gray-box modelling where coupling between electrical machine phase …

Human Arm Stiffness Estimation Method Developed For Overground Physical Interaction Experiments: Experimental Validation And Perspectives For Future Applications, Tarani Kanth Kamma

Masters Theses

"To build a physically interactive robot for overground applications, it is crucial to first understand the biomechanics of humans underlying overground physical human-robot interaction (pHRI) tasks. Estimating human arm stiffness during overground interactive tasks is a promising first step toward this goal. For this, an arm stiffness estimation technique was developed in our previous works that consider the unique challenges involving overground pHRI, such as the need to estimate the arm stiffness from a short duration of data with fewer repetitions. In this work, our stiffness estimation method is further validated with a passive spring setup with known stiffness values, …

Computational Fluid Dynamics Analysis Of Thermal-Hydraulic Phenomena In Nuclear Reactor Systems, Mehedi Hasan Tusar

Masters Theses

"A computational analysis of thermal-hydraulic processes in nuclear reactor systems is performed, leveraging Computational Fluid Dynamics (CFD) to advance the design and ensure the safety of nuclear reactors. Divided into two primary sections, the initial part examines thermal-hydraulic behavior in the Replacement Research Reactor (RRR) operating at 20 megawatts and evaluates potential enhancements for the Missouri University of Science and Technology Reactor (MSTR) to operate at an increased capacity of 2 megawatts from the existing 0.2 megawatts. Detailed simulations reveal insights into flow characteristics, temperature distributions, and pressure drops, highlighting the effective use of realistic and porous media modeling techniques …

Sub-Critical Crack Growth And Fatigue Behaviour Of Alkali Silicate Glass, Noah Weyrauch

Masters Theses

"Delayed failure in silicate glasses can be linked to subcritical crack growth (SCCG) where surface defects grow over time until catastrophic failure. This phenomenon originates from stress-enhanced chemical interactions between the environment (e.g. water) and the strained silicate bonds at the crack tip. SCCG must be accounted for to predict the long-term survivability of silicate-glass components. This study compares two methods to measure SCCG parameters for a commercial alkali silicate sealing glass and for a series of binary xNa₂O-(1-x)SiO₂ glasses, where 0.15 ≤ x ≤ 0.35. A constant moment double cantilever beam (DCB) technique was used to …

Production Of Glass-To-Metal Seals Using Additive Manufacturing Techniques, Aaron Read

Masters Theses

"Glass-to-metal (GtM) seals are hermetic barriers between glass and metal components, often used in the electronic and vacuum industries. Creating the seals traditionally requires heating all the components to the glass melting temperature, where the glass will flow and bond to the metal. Due to the manufacturing constraints of the individual components and sealing conditions there are geometric and material restrictions. Additive manufacturing techniques were used to make GtM seals to reduce these restrictions.

Hermetic, single pin seals were produced using printed metal shells, by selective laser melting (SLM), and digital light processing (DLP) printed glass preforms. Glass preforms were …

Open-Ended Hollow Coaxial Cable Resonance Sensing Via Permittivity Fluctuations For Applications To Exhaled Breath Health Monitoring, Peter Henry Holtmann

Masters Theses

"We report a pre-diagnostics breath analyzer based on the open-ended hollow coaxial cable resonator (OE-HCCR) to achieve real-time differentiation of healthy and compromised lung function through electromagnetic analysis of exhaled breath matter. A two-phase amplification scheme of electromagnetic signatures metered via the S11 phase curve offers high sensitivity to permittivity fluctuations in exposed airflow. The mathematical model of the breath analyzer is explained, followed by experimental validation of numerical findings from previous work. The collection of breath transient signals is performed through monitoring the reflected power magnitude and phase of the scattering parameter (S11) at the resonance frequency. Material fluctuations …

A Binary Integer Linear Programming Model For Optimizing Underground Stope Layout, Theophilus Mensah

Masters Theses

"Underground mine planning engineers face significant challenges when determining what geometry provides the most profitable and safe stope for extraction. Several techniques and optimization algorithms have been developed in recent years, but most fail to find optimal solutions because they are heuristic or LP-based without efficient geometric constraints. This thesis work proposes a two-dimensional binary linear programming (BILP) model for determining the optimal combination of blocks in a stope that maximizes the economic value of the layout of stopes for a sublevel deposit. The work draws from Queyranne and Wolsey’s (2017 & 2018) formulations of tight constraints for bounded up/down …

Effects Of Hemp Fibers On The Mechanical Performance Of Concrete, Hamida Baassou

Masters Theses

The construction industry is known to be globally the number one contributor to greenhouse gas emissions (GHG) and energy consumption. The purpose of this study is to examine the potential use of hemp as a concrete reinforcement, its mechanical properties and strength, its environmental and socio-economic advantages, and its limitations. To examine the mechanical performance of hemp fiber, 54 specimens will be tested for compressive, tensile, and flexural strength. This was done in two parts. In the first part hemp fibers in two different ratios (0.5v% and 1v%), and two different treatments (water and 5% sodium hydroxide) were added to …

Groundwater Movement In Boiling Spring, Onyx Spring, Yelton Spring, Wilkins Spring, Hudgens Spring And Natural Bridge Spring, Katherin Roxana Montes Chamorro

Masters Theses

"Onyx Spring, Boiling Spring, Yelton Spring, Wilkins Spring, Hudgens Spring, and Natural Spring are located on public land in Pulaski and Phelps County, Missouri. They were selected randomly to determine groundwater movement and compare water chemistry from the springs that are connected.

Using a dye tracing method, we were able to determine the direction of groundwater flow and a water multiparameter sonde was used to characterize the water chemistry at each point of the springs. As a result, from the six springs studied only three springs are connected which are Yelton, Onyx and Boiling Spring. Regarding to water chemistry this …

Theoretical Modeling And Experimental Investigation Of Phase Selection During Rapid Solidification Of Alloys, Azeez Aremu Akinbo

Masters Theses

"A novel model, rooted in time-dependent nucleation theory, has been created to explore how rapid solidification affects the extended solubility in metal alloys. This model was used to forecast solubility concerning undercooling in multiple binary aluminum (Al) alloys, and its predictions for both eutectic and peritectic systems closely match experimental data. It was demonstrated that this developed model surpasses the T0 line method, which does not consider the kinetic aspects of nucleation. Furthermore, the model can be extended to ternary and multicomponent phases by assuming that the scarcest element or the slowest diffusing component restricts nucleation. Al-Cu and Al-Cr, vital …

Tunable Metasurface For Efficient Harmonic Generation And Amplitude Modulation, Steve Mares

Masters Theses

The manipulation of microwave signals is critical in the information and communication technology industry. This research investigates the application of time-coding techniques on metasurfaces to achieve tunable control of electromagnetic signal transmission. The integration of mounted PIN diodes facilitates dynamic modulation of signal behavior. Both passive (without PIN diodes) and active (with PIN diodes) metasurfaces were analyzed through simulations using Ansys HFSS and validated with experimental measurements. A major contribution of this work is the design and testing of active metasurfaces that leverage PIN diodes for harmonic generation and amplitude modulation. The study reveals a clear relationship between modulating signal …

Process Improvement Of Cu(Ii)-Trymethylamine-Based Active Clay Measurement Test And Total Clay Measurement Test, Christopher Michael Remily

Masters Theses

Foundry work requires a mold made of a mixture of sand, “active clay” to absorb gas, and binders to combine the two and hold the molds shape. When the metal is melted to be poured into the mold, the solubility dramatically increases, causing gas to be temporarily dissolved in the metal. This gas causes small surface pits to form once the metal cools, causing part failure. This causes the need to absorb the gas. Since the clay is used in the process, there needs to be a way to determine how much remains active, which is done with a dye …

Advancing Winter Weather Adas: Tire Track Identification And Road Snow Coverage Estimation Using Deep Learning And Sensor Integration, Parth Kadav

Masters Theses

No abstract provided.

Nonlinear Finite Element Model For Functionally Graded Porous Circular/Annular Micro-Plates Under Thermal And Mechanical Load, Enrique Nava Munoz

Masters Theses

A nonlinear finite element model for micro circular/annular plates under thermal and mechanical loading is developed using a third order shear deformation theory. In the kinematic assumptions, the change of plate thickness is allowed and no transverse shear strains are considered on the top and bottom surfaces. A power-law distribution is utilized to account for variations of two constituents through the thickness of the plate. Three different types of porosity distributions are considered. The strain gradient effect in micro scale structures is considered using the modified couple stress theory. The dynamic version of the principle of virtual displacements is used …

Improving Irrigant Flow Characteristics For Enhanced Root Canal Therapy: A Numerical Study, Bibek Banjaday

Masters Theses

This numerical study investigates the flow characteristics within a root canal during a manual endodontic treatment. To underscore the difference in root canal geometry, a simplified root canal (frustum of a cone) and a more complex (realistic) root canal geometry were considered. The needle utilized in all simulations is a side-vented 30G KerrHaweIrrigation Probe, KerrHawe SA, Bioggio, Switzerland. For both root canal geometries, the effect of variation of fluid inlet velocity, needle insertion depth, and needle tilt angle on flow characteristics was examined via velocity contours, turbulent intensity, wall shear stress, and streamline and vector plots. The fluid was Sodium …

Enhancing Human Key Point Identification: A Comparative Study Of High-Resolution Vicon Dataset And Coco Dataset Using Bpnet, Bibash Lama

Masters Theses

Accurately identifying human key points is crucial for various applications, including activity recognition, pose estimation, and gait analysis. This study presents a high-resolution dataset created using the VICON motion capture system and three differently oriented 2D cameras, that can be used to train different neural networks for estimating the 2D key joint positions of the person from the 2D images or videos. The participants in the study included 25 healthy adults (17 males and 8 females) performing normal gait movements for about 2 to 3 seconds. The VICON system captured 3D ground truth data, while the three 2D cameras collected …

A Feasibility Study Of A Wearable Health Monitoring Device Powered By Thermoelectric Generators, Sarah Schneider

Masters Theses

Implementation of thermoelectric generators (TEGs) as a power source for embedded systems has increased with the push toward alternative and renewable energy sources. Thermoelectric generators produce electrical energy from thermal energy through the Seebeck effect. The Seebeck effect is a phenomenon seen when a temperature difference at a joint of two different metals generates a DC current and electromotive force [1]. This has made TEGs desirable for embedded system applications because it would allow for extended wireless operation. TEGs are based on solid-state technology which means they do not consist of any moving parts which reduces wear and tear with …

Sel4 On Risc-V - Developing High Assurance Platforms With Modular Open-Source Architectures, Michael A. Doran Jr

Masters Theses

Virtualization is now becoming an industry standard for modern embedded systems. Modern embedded systems can now support multiple applications on a single hardware platform while meeting power and cost requirements. Virtualization on an embedded system is achieved through the design of the hardware-software interface. Instruction set architecture, ISA, defines the hardware-software interface for an embedded system. At the hardware level the ISA, provides extensions to support virtualization.

In addition to an ISA that supports hypervisor extensions it is equally important to provide a hypervisor completely capable of exploiting the benefits of virtualization for securing modern embedded systems. Currently there does …

Interactive Architecture - Intervention Of Virtual Business On Commercial Space, Yihao George Xu

Masters Theses

Traditional mall-based restaurants, such as P.F. Chang’s in the Providence Place Mall, have primarily focused on site-based dining and bar services. However, the food provided by this chain restaurant often lacks depth, and customers seldom learn the story behind the dishes. This thesis explores the integration of mixed reality technology within the physical environment of P.F. Chang’s, an American Chinese restaurant chain with over 300 locations, aiming to transform it into an authentic Shanghai food culture experience. This experience combines virtual and physical stimuli to evoke various periods of Chinese history, providing a unique encounter for customers.

The proposed transformation …

Unveiling Pain: Wearables For Objective Pain Measurement, Hanqing Tang

Masters Theses

">">Pain perception is a subjective experience that differs significantly among individuals, often leading to inconsistencies in assessment and management. A critical issue within this context is the gender bias in pain evaluation, which contributes to unequal treatment and perpetuates gender inequality within the healthcare system. This thesis presents an in-depth investigation of the problem and proposes the development of a wearable device for objective pain assessment. Physiological parameters — Electrocardiography (ECG) can be collected from cardiac sound signals auscultated by fabrics via nanometre-scale vibrations. Machine learning methods can accurately classify heart rate and acute pain intensity of participants. …