Engineering Commons^™

The Performance Analysis And Optimization Of Wave Energy Converters From Modeling To Basin Testing, Lauren Dickson

Electronic Theses and Dissertations

The successful development and optimization of wave energy converters (WECs) are pivotal to the pursuit of sustainable and renewable energy sources. This thesis explores the elements in a workflow that develops and demonstrates the protocols for the optimization of WECs using a rapid design\build\test procedure. This thesis establishes the characterization of scaled ocean test sites, develops the performance metrics, generates the performance modeling techniques to predict the optimum design geometries which will be produced for final testing, and finally, establishes the basin test plan which will be used to conduct the testing on the optimum design. The findings of this …

Mechanical Characterization Of Automated Fiber Placement And Additive Manufacturing Hybrid Composites, Lucan Haviland

Electronic Theses and Dissertations

This thesis presents the optimization of processing parameters based on the mechanical properties of Continuous Fiber-Reinforced Thermoplastic (CFRTP) Unidirectional (UD) consolidated tapes. The UD tapes were consolidated using an AFP head and a thermoforming press for comparison. The adhesive strength of hybrid parts consisting of CFRTP UD tape bonded to a 3D-printed substrate with the same matrix system were investigated. Large Area Additive Manufacturing (LAAM) was utilized for the 3D-printed parts. Different types of thermoplastic composite materials were explored, including Glass Fiber reinforced Polyethylene Terephthalate Glycol (GF/PETG), Carbon Fiber reinforced Polyethylene Terephthalate Glycol (CF/PETG), Carbon Fiber reinforced Polycarbonate (CF/PC), and …

Hemodynamic Assessment Of Y-Incision Aortic Root Enlargement Using Computational Simulations, Astitwa Ghimire

Electronic Theses and Dissertations

The Yang procedure is a new aortic root enlargement technique used to enlarge the aortic annulus by multiple valve sizes. The procedure prevents patient prosthesis mismatch and establishes a viable platform for future valve-in-valve implantation. This study used the Yang procedure to investigate the hemodynamics in the aortic root and bioprosthetic valve regions after aortic root enlargement. Results indicate the velocity magnitude at the sinus regions of a patient who underwent the Yang procedure was slower, indicating risks of flow stasis and thrombosis. Simulation results denote computational models can be created for optimization of surgical procedures.

Fatigue And Fracture Of Electron Beam Melting Ti-6al-4v, William A. Grell

Electronic Theses and Dissertations

For applications in the aerospace field, selection of materials for a given design requires an understanding of critical properties, like fatigue and fracture, in addition to static mechanical and physical properties. With the ongoing advancements in metallic additive manufacturing techniques and the interest in applying the process to aerospace applications, there is a clear need to fully characterize properties. Arguably, the most attractive alloy for applications in aerospace is the Ti-6Al-4V alloy. The current dissertation examines the mechanical properties of the alloy, made by the Electron Beam Melting (EBM) Powder Bed Fusion (PBF) method. As illustrated in this work, the …

A Virtual Method For Establishing Femoral Stem Position In Total Hip Arthroplasty, Samuel Mattei

Electronic Theses and Dissertations

Total hip arthroplasty (THA) is one of the most successful orthopedic surgeries performed, in which the hip joint is reconstructed to improve functionality and decrease pain in the joint. Despite the success of these procedures, femoral stem misalignment remains an area that influences THA success. The relationship between the femoral stem geometry and implanted femoral stem size and orientation is underreported due to limitations in the collection of radiographic data used for clinical pre-operative templating. Furthermore, the influence of anatomic measurements on the direction and size of the femoral stem are not considered due to imaging technique and difficulties associated …

Finite Element Modeling Of Patient-Specific Total Shoulder Arthroplasty, Ignacio Rivero Crespo

Electronic Theses and Dissertations

Total Shoulder Arthroplasty (TSA) is a surgical procedure designed to improve joint functionality by replacing the articulation between the humeral head and the glenoid fossa. Anatomic Total Shoulder Arthroplasty (aTSA) and Reverse Total Shoulder Arthroplasty (rTSA) are two types of replacement surgery to relieve pain and restore function of the shoulder. The overall goal of this study was to evaluate the effects of variation of certain patient and implant alignment parameters that may influence long-term outcomes of these surgical procedures, including kinematics, joint loads and contact mechanics. Computational models of six TSA subjects, three aTSA and three rTSA, were created …

Measurement Of Conduction, Radiation, And Convection Thermal Energy To Assess Baking Performance In Residential Ovens., Sean Simpson

Electronic Theses and Dissertations

Residential ovens are complicated thermal environments capable of delivering convection, conduction, and radiation heat transfer to food. The amount and mode of heat transfer can change based on the design of the oven cavity, cooling systems, and oven cycle algorithms. Studies have shown that the changes in one heat transfer mode can have an impact on the quality of baked goods. The many variables involved make designing residential ovens a time consuming and costly process. The goal of this study is to adapt thermal energy sensing technology to collect energy data from a residential oven and develop correlations to quality …

Reducing Energy Usage For Residential Furnace Blowers: Blade Re-Design And Assessment Of The Impact Of Flow Non-Uniformity Elimination, Mohammad Mirmohammadi

Electronic Theses and Dissertations

Residential furnace blowers are widely used in North America, but they often are designed to be low-cost rather than highly efficient. In this study, analysis of the literature yields an estimated adiabatic efficiency for typical furnace blowers of approximately 48%. The geometry of a typical furnace suggests much of the cause of this low efficiency is due to poor flow uniformity entering the blower. While the specific diameter and specific speed of the blower lie far from the Cordier diagram locus, these parameters cannot be dramatically changed due to space constraints. Thus, this study aims to quantify the efficiency gain …

Application Of Equilibrium-Based Pah Adsorption To Modelling Graphene Synthesis In A Microwave-Assisted Plasma Reactor, Jiahai Fan

Electronic Theses and Dissertations

Graphene is a new material with potential to significantly impact many applications due to its unique physical and chemical properties. However, the commercialization of graphene is impeded by issues in graphene mass production. Recently, a potential production method that uses a microwave-assisted plasma reactor to produce graphene has been developed, and this method might make mass production of graphene possible. To aid in development of this new method, a novel computational model to simulate graphene synthesis in this system was developed. While it was the first attempt at modelling graphene synthesis in such a system, the model required improvement due …

The Importance Of Accurately Predicting Corner Separations In Fan Stall Point Identification With Steady Rans: Computations With The Helicity-Corrected Spalart-Allmaras Turbulence Model, Zhifan Yu

Electronic Theses and Dissertations

This thesis applies a modified Spalart-Allmaras (SA) turbulence model, the helicity-corrected Spalart-Allmaras (HCSA) model, in incompressible steady Reynolds-averaged Navier-Stokes (RANS) computations to reduce the numerical simulation run time for fan stall inception prediction. Computations are carried out using the OpenFOAM package. This manuscript-style thesis contains two main chapters, each stemming from conference papers. First, the HCSA turbulence model is applied to a low-speed axial fan, known as the boundary layer ingestion (BLI) fan, for fan stall behavior simulation. Both RANS and unsteady RANS (URANS) with the HCSA model and RANS with the original SA model are performed, with all results …

Model-Guided Extremum Seeking Control For Mechanical Ventilators, Ryan Keith Wardell

Electronic Theses and Dissertations

Mechanical ventilators are an important lifesaving medical device and because of the COVID-19 pandemic, they were in a massive demand for them to help the patients most severely affected by the disease. A large number of open-source hardware ventilator projects were established during the pandemic, most of which did not provide sufficient information on the design of their control systems. In this thesis, a model-guided extremum seeking control scheme is proposed for use on a open-source hardware ventilator design. The performance of the control scheme is intended to not be significantly affected by changes to the patient, nor to variations …

Fully Coupled Fluid Structure Interaction Simulation Of Bioprosthetic Heart Valves: A Numerical And Experimental Analysis, Masod Sadipour

Electronic Theses and Dissertations

Aortic stenosis impacts approximately 7% of the global population. In the past decade, the role of computational modeling has been becoming considerably important in the design of BHVs. To obtain reliable solutions in computational modeling, it is essential to consider accurate properties of bioprosthetic heart valves (BHVs), such as density and mechanical properties. Previous computational studies assumed (bovine pericardium) BP used in BHVs density was comparable to water or blood. Yet, BP is subjected to multiple treatments like fixation and anti-calcification. In Chapter 2, I measured BP density and its effect on BHV leaflet stress and strain. In the second …

The Modernization Of Large Power Transformer Tanks, Babajide O. Williams

Electronic Theses and Dissertations

Due to the current demands placed on the power grid in terms of climate change, increasing urbanization, and terrorist attacks, the U.S. government in response to these demands, mandated that all the grid components be modernized in order to increase their reliability. As a critical component of the grid, Large Power Transformers (LPTs) play a key role in ensuring sustainable power generation and distribution. A literature search performed in this work and the analysis of data retrieved from the search showed that the tanks of these LPTs are critical to their durability, longevity, and reliability. Therefore, the reliability of LPTs …

Patient Movement Monitoring Based On Imu And Deep Learning, Mohsen Sharifi Renani

Electronic Theses and Dissertations

Osteoarthritis (OA) is the leading cause of disability among the aging population in the United States and is frequently treated by replacing deteriorated joints with metal and plastic components. Developing better quantitative measures of movement quality to track patients longitudinally in their own homes would enable personalized treatment plans and hasten the advancement of promising new interventions. Wearable sensors and machine learning used to quantify patient movement could revolutionize the diagnosis and treatment of movement disorders. The purpose of this dissertation was to overcome technical challenges associated with the use of wearable sensors, specifically Inertial Measurement Units (IMUs), as a …

Novel Approach For Non-Invasive Prediction Of Body Shape And Habitus, Emma Young

Electronic Theses and Dissertations

While marker-based motion capture remains the gold standard in measuring human movement, accuracy is influenced by soft-tissue artifacts, particularly for subjects with high body mass index (BMI) where markers are not placed close to the underlying bone. Obesity influences joint loads and motion patterns, and BMI may not be sufficient to capture the distribution of a subject’s weight or to differentiate differences between subjects. Subjects in need of a joint replacement are more likely to have mobility issues or pain, which prevents exercise. Obesity also increases the likelihood of needing a total joint replacement. Accurate movement data for subjects with …

Efficient Sintering Of Lunar Soil Using Concentrated Sunlight, Diprajit Biswas

Electronic Theses and Dissertations

Construction material is one crucial need for long-term habitation on the moon. When concentrated for high heat flux, solar radiation can heat lunar soil or regolith until it sinters at temperatures above 900°C. The solid, sintered soil simulant can be used as construction material. This work explores the conditions leading to effective lunar soil sintering for both direct and indirect irradiated sintering. Lunar soil simulants were sintered using concentrated light from a xenon-arc lamp with varying heat flux intensity. During direct sintering of LHS-1, a sintering range of 860°C-1140°C corresponding to a peak heat flux of 105-120 kW/m2 was identified …

The Future Is Now In Twisted Coil Polymer Actuators (Tcpa), Ryan Ronquillo

Electronic Theses and Dissertations

This thesis aimed to fabricate and test twisted coiled polymer actuators (TCPA) to understand the mechanical and thermal aspects of this artificial muscle fiber. The purpose of this thesis was to find a linear relationship using the LVDT sensor, fabricating TCPA fibers, and interpreting the data. The project tested whether nylon/polymer could be used as a better artificial muscle fiber.

This research accomplished three goals: (1) designing and fabricating a system capable of creating supercoiled muscle fibers consistently, (2) calibrating the Linear Variable Differential Transformer (LVDT) and Core, and (3) analyzing/interpreting the data of the Twisted Coiled Polymer Actuators (TCPA) …

Investigating The Effectiveness Of A Haptic Feedback System To Improve The Gait Speed Of Older Adults In Overground Walking, Md Tanzid Hossain

Electronic Theses and Dissertations

While the use of tactile feedback for modifying gait has recently shown promising results in a number of research studies, there has been little attention given to its ability to effect change in the gait of older adults nor has the effect of the frequency of this feedback been examined. Given the important associations of walking speed with the health of older adults, the goal of this study was to determine if a recently developed haptic feedback system could increase the walking speed of older adults and whether the frequency at which this feedback was provided would have an impact …

Mechanics And Mechanisms Of Fracture For An Eastern Spruce Subject To Transverse Loading Using Acoustic Emission, Parinaz Belalpour Dastjerdi

Electronic Theses and Dissertations

Due to its excellent structural qualities and accessibility, wood is among the most often utilized structural materials. Despite its ubiquity, wood poses numerous challenges. It is heterogeneous and anisotropic. It has a complex hierarchical ultrastructure, and the properties can have wide variation within a species, and indeed within an individual tree. This work aims to improve our understanding of the strength and fracture behavior of spruce-pine-fir (south) (SPFs), particularly in cross-grain direction. This study’s primary goal is to examine the relationship between crack propagation and cross grain morphology under the following loading configurations: compact tension, compression, and rolling shear. The …

Application Of Particle Transfer By Dipping Using Polymer Binder, Md Ibrahim Khalil

Electronic Theses and Dissertations

The demand for particle transfer is increasing in various industries, such as manufacturing, metal joining, microfluidics, roller lubrication process, fuel cells, super-capacitors, hybrid coating, and protective layer applications. As a result, the importance of efficient transfer of solid micron-size particles is becoming more crucial. Submicron-sized particles can easily adhere to solid substrates due to negligible gravitational force, while micron-sized or larger particles require a binder to overcome the gravitational effects. This thesis aims to investigate the interactions between microparticles and polymer thin film on cylindrical substrates using particle transfer methods. The process parameters are optimized and demonstrated two applications of …

Feasibility Of Thermoplastic Extrusion Welding As A Joining Method For Vacuum-Assisted Additively Manufactured Tooling, Chase C. Flaherty

Electronic Theses and Dissertations

In recent years, additive manufacturing (AM) has been successfully utilized for the production of large-scale composite tooling. Within these endeavors, however, limited research has focused on joining methods between printed sections. This work evaluates the feasibility of thermoplastic extrusion welding as a joining method for additively manufactured tooling structures. This joining method was assessed based on industry specifications of conventional thermoset tooling for wind blade manufacturing utilizing the vacuum-assisted resin transfer molding (VARTM) process. The specifications include requirements for the mechanical strength, vacuum integrity, roughness, and hardness of the tool surface. The feasibility of this welded polymer joint was demonstrated …

Investigation Into Sintered Lunar Regolith Construction Methods And Novel Usability Evaluation, Thomas A. Cox

Electronic Theses and Dissertations

Since the Apollo missions in the late 1960's, there has been a growing interest shared by many countries around the world to return to the Moon and establish a permanent Lunar settlement. The first phase of temporary Lunar bases will be established over the next several years. For a permanent human presence on the Moon, it will be necessary to use locally available resources for the construction of Lunar habitats and other infrastructure. Sintering Lunar regolith has been shown to be a promising method for producing structural material with a variety of desirable properties from strength to radiation shielding. While …

Drop Impact On Dry And Liquid Infused Substrates With Micro-Wells., Ahmed Nazrul Islam

Electronic Theses and Dissertations

Drop impact on different types of surfaces are important physical concepts that are routinely found in day-to-day life and such studies have immense application for various types of industries. One such important application of drop dynamics is in the field of aviation science which is concerned of very large freezing drizzle drops impacting on airplane wings. Such drops are known as supercooled large droplets (SLD), and they pose a great risk and have been long known to have caused notable accidents in the past. SLDs are liquid drops that can remain in the state of liquid phase and grow into …

Super P-Sulfur Cathodes For Quasi-Solid-State Lithium-Sulfur-Batteries., Milinda Bharatha Kalutara Koralalage

Electronic Theses and Dissertations

Lithium-Sulfur (Li-S) batteries have become a promising candidate to meet the current energy storage demand, with its natural abundance of materials, high theoretical capacity of 1672 mAhg-1, high energy density of 2600 Whkg-1, low cost and lower environmental impact. Sulfide based solid state electrolytes (SSEs) have received greater attention due to their higher ionic conductivity, compatible interface with sulfur-based cathodes, and lower grain boundary resistance. However, the interface between SSEs and cathodes has become a challenge in all solid-state Li-S batteries due to the rigidity of the participating surfaces. A hybrid electrolyte containing SSE coupled with a small amount of …

Engineering 3d Architected Metamaterials For Enhanced Mechanical Properties And Functionalities., Huan Jiang

Electronic Theses and Dissertations

Compared with conventional materials, architected metamaterials have shown unprecedented mechanical properties and functionalities applications. Featured with controlled introduction of porosity and different composition, architected metamaterials have demonstrated unprecedent properties not found in natural materials. Such design strategies enable researchers to tailor materials and structures with multifunctionalies and satisfy conflicting design requirements, such as high stiffness and toughness; high strength with vibration mitigation properties, etc. Furthermore, with the booming advancement of 3D printing technologies, architected materials with precisely defined complex topologies can be fabricated effortlessly, which in turn promotes the research significantly. The research objectives of this dissertation are to achieve …

Modeling, Simulation And Control Of Microrobots For The Microfactory., Zhong Yang

Electronic Theses and Dissertations

Future assembly technologies will involve higher levels of automation in order to satisfy increased microscale or nanoscale precision requirements. Traditionally, assembly using a top-down robotic approach has been well-studied and applied to the microelectronics and MEMS industries, but less so in nanotechnology. With the boom of nanotechnology since the 1990s, newly designed products with new materials, coatings, and nanoparticles are gradually entering everyone’s lives, while the industry has grown into a billion-dollar volume worldwide. Traditionally, nanotechnology products are assembled using bottom-up methods, such as self-assembly, rather than top-down robotic assembly. This is due to considerations of volume handling of large …

Thermal Analysis Based Design Of Hollow Shaft For Improved Cooling Of Induction Motors, Isabelle Dinh

Electronic Theses and Dissertations

This thesis investigates methods of implanting a forced liquid convection heat recovery system within an induction motor’s shaft to cool the rotor.

The objective is to design a hollow shaft that can meet the target goals of keeping the components under an average temperature of 100℃ under different motor power conditions. Three hollow shaft design cases were studied at steady state conditions to evaluate their heat transfer performance and surface temperature to meet the goals of the study. This includes the design of a counterflow, counterflow with fins, and duct design.

It is found that third design is able to …

Assessing The Economic Feasibility Of Capturing And Utilizing Carbon Dioxide From Ethanol Production In South Dakota, Makiah Stukel

Electronic Theses and Dissertations

Since the Industrial Revolution, anthropogenic greenhouse gas (GHG) emissions have spiked dramatically, prompting discussions on climate change. Mitigating climate change requires significant reductions in global carbon dioxide (CO2) emissions as CO2 is the most abundant anthropogenic GHG. A process that assists in offsetting the exponential growth in CO2 emissions is carbon capture and storage (CCS). Integrating carbon capture technology into the ethanol industry can provide an economically feasible way to achieve net reductions in CO2 emissions. The proposed work investigates the economic viability of applying CCS technologies to the 16 ethanol facilities in South Dakota (SD) and quantifies the potential …

Quantifying The Effects Of Hvac Operation To Mitigate Aerosol Concentration In A Classroom Using Cfd, Scott Deprez

Electronic Theses and Dissertations

Heating, ventilation, and air conditioning (HVAC) is a complex mechanical system for the transition of air between outdoor and indoor areas. These systems are directly responsible for temperature, humidity, and air flow into any given space, thereby providing a level of comfort to those who live indoors. These systems account for 52 percent of U.S. energy consumption. When designing HVAC systems, indoor air quality (IAQ) is the main focus for achieving safe and clean air, such as in the case of airborne diseases. HVAC systems are responsible for the flow of air in indoor spaces and thereby expand the transmissible …

Superhydrophobic And Oleophobic Surfaces. Synthesis And Applications, Zirui Liu

Electronic Theses and Dissertations

Surface patterning is an overwhelming approach to mechanically modifying metal surfaces and improving their tribological properties, such as repellency, lower friction, and more excellent corrosion resistance. Patterned surfaces can be applied to various industrial uses, such as cutting tools, submarines, and self-cleaning surfaces. In this paper, the novel nature-inspired flat-top-pillar "double-undercut" designs were proposed to achieve an apparent angle that satisfies super-hydrophobicity and endure higher pressure on which external forces are exerted. The main objective is to enlarge the change in Gibbs free energy for the system to exhibit a heterogeneous wetting to a homogeneous one by excavation on the …