Digital Commons Network^™

Numerical Modeling Of Firebrand Transport, Antonio Q. Cervantes

Master's Theses

Firebrand showers are the fastest and most complex form of wildfire spread by generating spot fires in random locations. This randomness is due to many factors, including turbulent wind and particle shape. This work seeks to understand how small-scale turbulence affects firebrand landing distribution and develop a methodology to couple firebrand transport with wildfire simulations. Understanding transport at small scales can provide knowledge on large-scale transport in wildfire simulations. The computational domain and the mesh size in wildfire simulations are very large and do not feature small-scale turbulence. High-resolution small-scale turbulent and uniform boundary layers at various turbulence intensities are …

Mmteg Heatsink Design, Peyton Nienaber, Kadin Feldis, Alec Savoye, Jack Waeschle

Mechanical Engineering

In this document, Cal Poly Senior Design Team F16 presents a summary of its work developing a suitable heatsink for Gas Technology Institute’s Methane Mitigation Thermoelectric Generator. After several months of iterating between experimental testing and simulated heat transfer, a suitable prototype was selected for use in further refining simulation parameters. This was called the structural prototype and it allowed Team F16 to confirm several remaining unknowns relating to component thermal conductivity. All documentation of this process can be found in Preliminary, Critical, and Interim Design Review documents (PDR, CDR, IDR), included in this report. Having a realistic model …

An Initial Study Of Properties Of Monolithic Silicon Dioxide Parts Produced By The Ceramic On-Demand Extrusion Process, Sam Sujit Choppala

Master's Theses

The ceramic on-demand extrusion (CODE) process is an additive manufacturing process for technical ceramics, which features an oil bath and partial drying to print stronger green bodies due to better preservation of the printed specimen structure and reduction of uneven part evaporation. A 3D printer capable of performing the CODE process is built with subsystems including motion, extrusion, and heating, and is controlled through LinuxCNC. The CODE printer and process is tested with silicon dioxide as the technical ceramic. High strength silicon dioxide parts are essential in various present-day industries such as dental, medical, and semiconductor. A 55vol% solids loading …

Acoustic Cloak Design Using Generative Modeling And Reinforcement Learning, Linwei Zhuo

Master's Theses

Metamaterials are engineered composites that can exhibit acoustic, electromagnetic, elasto-dynamic and mechanical properties that are not found in natural materials Due to the complexity of the target objective functions, it is difficult to find the globally optimized solutions in the inverse design of metameterials. This thesis proposes and outlines two model, a gradient-based optimization method combined with generative networks (2D-GLOnets) and a reinforcement learning (RL) model, that can find the optimized metamaterial structures across a wide range of parameters. By perturbing the positions of each cylindrical scatterer in a planar configuration, 2D-GLOnets and the RL model with Deep Deterministic Policy …

Golf Club Cleaner, Owen Roach, Chris Wertenberger, Michael Skerlong

Williams Honors College, Honors Research Projects

Cleaning golf clubs can be a tedious process, however a necessary one to maintain equipment. Clubs are normally cleaned by filling a bucket with soap and water, soaking all the clubs to be cleaned, then scrubbing each one individually. An automatic club cleaner would make this process much easier and more enjoyable. Using electric motors, the club cleaner would have spinning brushes in soap and water to quickly and easily clean the club head. The machine would have different sections for cleaning the club head, polishing the club face, and cleaning the grip. The cleaner should be inexpensive and easy …

Acoustic Lens Design Using Machine Learning, Wei-Ching Wang

Master's Theses

This thesis aims to contribute to the development of a novel approach and efficient method for the inverse design of acoustic metamaterial lenses using machine learning, specifically, deep learning, generative modeling, and reinforcement learning. Acoustic lenses can focus incident plane waves at the focal point, enabling them to detect structures non-intrusively. These lenses can be utilized in biomedical engineering, medical devices, structural engineering, ultrasound imaging, health monitoring, etc. Finding the global optimum through a traditional iterative optimization process for designing the acoustic lens is challenging. It may become infeasible due to high dimensional parameter space and the compute resources needed. …

Further Exploration Of Optical/Thermal Interaction Effects On High-Power Laser System Performance And Optimization Through Multiphysics System-Level Modeling, Nathaniel J. Butt

Browse all Theses and Dissertations

High-power laser systems (HPLS) have wide-ranging applications in many prominent areas. HPLS use laser diodes to pump fiber gain media. Understanding the functionality of both components is critical for achieving effective HPLS operation. System optical efficiency is a function of diode junction temperature. As junction temperature changes, the wavelength spectrum of the diode output shifts causing optical power losses in the fiber gain media. Optical/thermal interactions of the dynamically coupled laser diodes and fiber gain media are not fully understood. A system level modeling approach considering the interactions between optical performance and component temperature is necessary. Four distinct models were …

Computational Analysis Of Changing Wavelength On Bottom Rib And Side Rib Wavy Microchannel Heat Sinks, Ty C. Kieger

Master's Theses

As the power capacity of microelectronics continues to increase while their volume and size decrease, many different on-chip methods including microchannel heat sinks (MCHS) are being explored to cool down the temperature of these electronics. Wavy MCHS have been proven to yield better heat transfer performance compared to straight MCHS, while only producing a slightly larger pressure drop. This study investigates the heat transfer performance of MCHS following a vertical wavy design and a horizontal wavy design that have the same cross-sectional area. The simulations show that vortices are produced along the channel in the peaks and troughs of the …

Electrical Characterization Of Phytoplankton Suspensions Using Impedance Spectroscopy., Margaret R Jett

Electronic Theses and Dissertations

Phytoplankton are closely monitored because of their important environmental role, and the impacts they have on their local ecosystems. Some phytoplankton respond to stress by producing lipids, which can be harvested for biofuels and other chemicals. Microfluidic devices have been important in improving the portability and throughput of phytoplankton characterization methods, increasing their potential for in situ use. This study utilized a small sample of phytoplankton suspended in a stagnant medium and measured the impedance response using a lab-on-chip and impedance analyzer. The individual cell characteristics were derived from the impedance response of the group. The goal was to characterize …

Material Detection With Thermal Imaging And Computer Vision: Potentials And Limitations, Jared Poe

Graduate Theses and Dissertations

The goal of my masters thesis research is to develop an affordable and mobile infraredbased environmental sensoring system for the control of a servo motor based on material identification. While this sensing could be oriented towards different applications, my thesis is particularly interested in material detection due to the wide range of possible applications in mechanical engineering. Material detection using a thermal mobile camera could be used in manufacturing, recycling or autonomous robotics. For my research, the application that will be focused on is using this material detection to control a servo motor by identifying and sending control inputs based …

Physics In The Garden, Dae Jin Park, Jiyoun Jung, Tanner Haun Bush

Mechanical Engineering

The Final Design Review (FDR) report explains the initial research, design process, finalized design, manufacturing and assembly methods, and testing done by the senior project group in Mechanical Engineering Department at California Polytechnic State University, San Luis Obispo. For this project, the San Luis Obispo Botanical Garden would like to develop an educational and interactive exhibit that conveys a lesson in physics. The Botanical Garden envisions an exciting feature to educate children on physical science and broaden the appeal of the garden. This document captures the problem’s scope, requirements, initial concept, design research, target demographic, ideation, evaluation processes, and project …

Human Powered Vehicle Capstone, Maya L. Washington, Ryan Apolonio, Marc Sunga, John Rettenmier, Dr. Allen Wilson

Honors Thesis

In the ASME Human Powered Vehicle Challenge (HPVC), students design, develop, construct, and test different designs of human-powered vehicles. The design utilizes two wheels, the rear of which is responsible for power transmission from a pedal crank and braking through a disc and caliper. The design also utilizes the front wheel fork wheel for steering. Steering and braking are controlled by two levers on the handlebars. To determine whether the design was sufficient, it was compared to the standards set by ASME, including maximum weight, minimum speed, minimum turning radius, minimum ride distance, load testing, harness verification, and a complete …

Monitoring Of Overhead Polymer Core Composite Conductors Under Excessive Mechanical Loads Using Fiber Bragg Grating Sensors, Daniel H. Waters

Electronic Theses and Dissertations

This combined experimental and numerical study addresses mechanical effects associated with static and dynamic loading of novel High Temperature Low Sag (HTLS) transmission line polymer core composite conductors. The developed methodology was successfully applied to ACCC® to explain the complex failure mechanisms associated with combined bending and tension loading. Furthermore, the use of Fiber Bragg Grating (FBG) sensors was investigated for the first time to monitor the ACCC® design during installation and in-service.

Transverse low-velocity impacts to the ACCC® conductor having either free or constrained end conditions and large axial tensile loads were performed. It was identified that the most …

Sources Of Quality Uncertainty In Laser Powder Bed Fusion Metal Additive Manufacturing, Zachary Young

Doctoral Dissertations

"Powder based additive manufacturing (AM) exhibits tremendous uncertainties, where variations in build quality is present despite utilizing similar build processing parameters. First, this work reports the features and formation mechanisms of five unique types of spatter during the LPBF process by in-situ high-speed, high-energy x-ray imaging. The unique physical characteristics of spatter are determined. The effect of laser scan speed and laser power on spatter formation, ejection, and mitigation are determined. Second, this work addresses the uncertainty challenge by identifying the sources of uncertainty in SLM by in-situ characterization due to variations from the additive manufacturing processing parameters needed for …

Customizable Armor Set, Olivia Reedy

Williams Honors College, Honors Research Projects

This project is intended to help people who make costume armor by reducing the amount of time and money it takes to create a set of armor. Making armor can take a lot of resources for beginners, and this project is intended to help hobbyists with that process. This customizable armor set goes through the engineering design process, from the initial design of the parts to creating the prototype using vacuum forming. The prototype armor can be painted and adhered to using acrylic paint and contact cement, respectively, and fits three sizes of small, medium, and large.

Prosthetic Foot Shell, Ql+, Kathryn Victoria Versteeg, Jackson A. Tucker, Ethan William Frey

Mechanical Engineering

This final design review includes an overview of our project and the steps we have taken to create our final product. We discuss the background research conducted, including various products like the foot shell we are trying to design and its related patents, along with similar past senior projects. As our product is considered a medical device, there are also certain standards that we must comply with. After determining our problem statement, we established what we believe to be the wants and needs of our user. These wants and needs were converted into specifications for our design, with durability as …

Start-Up Power Requirements Of Ammonia Filled Aerospace Thermosyphon Heat Pipes, Eric Chu

Master's Theses

Boiling and condensing of internal working fluids are essential heat transfer concepts which heat pipe technology relies on for transporting a large amount of heat between two distanced points effectively. Tilt angle and working fluid saturation temperature have a direct impact on how well the evaporator is flooded. This paper focuses on how the tilt angle and the working fluid saturation temperature affect the start-up heat input requirements for an S shaped axial grooved ammonia thermosyphon heat pipe. A series of experiments was performed by supplying and extracting heat to the evaporator and condenser of the thermosyphon heat pipe. Temperature …

Development Of A Computational Elbow Joint Model To Analyze The Effects Of Synovial Fluid On Articular Cartilage During Joint Motion, Abhishek Yellapragada

Master's Theses

While significant advances have been made in the development of computational elbow joint models, fluid-structure interaction (FSI) in the elbow joint has not yet been explored. The objective of this study is to develop a computational elbow joint model to simulate the effects of synovial fluid on articular cartilage during flexion, extension, pronation, and supination. The model was developed with anatomically accurate 3D bone geometries; articular cartilage geometries that were derived from the 3D bone geometries; ligaments defined as linear springs; muscles embedded as joint non-linear stiffness; and a fluid domain that encompassed the joint articulations with a homogenous, incompressible, …

Time-Invariant Tensile Necking Of Blood On An Electrowetting Digital Microfluidic Platform, Curtis Young

Master's Theses

Recent developments in electrowetting-on-dielectric (EWOD) technology have expanded the possibilities for testing methods and investigation of blood. This work evaluated the development of necking geometry of whole blood and red blood cell (RBC) suspensions on a digital microfluidic (DMF) platform. This was achieved by applying tension to liquid droplet specimens on an EWOD-based device using applied electrowetting forces, thereby inducing necking. The deformation of 5 μL fluid specimens was recorded using neck radius and minimum neck width as two characteristic geometric parameters. Tensile tests were performed on phosphate-buffered saline (PBS), whole blood diluted in PBS, and RBCs suspended in PBS …

Effect Of Nicotine Exposure On Fatigue Mechanics Of Murine Arteries, Elizabeth Ho

Master's Theses

Nicotine is an addictive substance found in electronic cigarettes (e-cigarettes) and cigarettes, and the use of such products has growing concern because of the prevalent use by young adults. Nicotine exposure degrades arterial tissue and results in increased arterial stiffness, which is linked to cardiovascular events, such as stroke and myocardial infarction. The hypothesis of this research is that fatigue loading reveals changes to the mechanical behavior of nicotine-treated arteries that is more informatively discriminating than stiffness alone. Ten murine arteries, five untreated and five nicotine-treated, were subjected to cyclic fatigue loading in an open-circumferential configuration by a custom tensometer …

Formation Of Clot Analogs Between Co-Flow Fluid Streams In A Microchannel Device, Sue-Mae Saw

Master's Theses

Hemodynamics plays an important role in the formation of blood clots, for which changes in hydrodynamic stresses and transport phenomena can initiate or inhibit the clotting process. The fibrin network is highly influential in the structural mechanics of a clot. This work demonstrated an ability to produce clot analogs at the boundary between co-flow fluid streams, and investigated the dependence of clot shape and density distribution on flow conditions. The time evolution of fibrin clots formed in microchannel flow was investigated using fluorescence imaging. Clots were formed in a polydimethylsiloxane (PDMS) microfluidic device which consisted of a Y-shaped microchannel with …

Design Of A Canine Inspired Quadruped Robot As A Platform For Synthetic Neural Network Control, Cody Warren Scharzenberger

Dissertations and Theses

Legged locomotion is a feat ubiquitous throughout the animal kingdom, but modern robots still fall far short of similar achievements. This paper presents the design of a canine-inspired quadruped robot named DoggyDeux as a platform for synthetic neural network (SNN) research that may be one avenue for robots to attain animal-like agility and adaptability. DoggyDeux features a fully 3D printed frame, 24 braided pneumatic actuators (BPAs) that drive four 3-DOF limbs in antagonistic extensor-flexor pairs, and an electrical system that allows it to respond to commands from a SNN comprised of central pattern generators (CPGs). Compared to the previous version …

Molecular Dynamics Study Of Sintering Behavior Of Single-Crystal, Bimetallic Core/Shell Alloy, And Intermetallic Alloy Nanoparticles, Jungmin Jeon

Electronic Theses and Dissertations

There has been rapidly growing interest in the sintering process of nanoparticles (NPs) among academia and modern industry due to their promising applications in additive manufacturing (AM) based on the overall improved properties at nanoscale. In the past decade a lot of experimental and computational work has been conducted to study the sintering process of powder materials. However there is still a significant knowledge gap in a fundamental understanding of the thermodynamics and nanostructural evolution of NPs undergoing additive manufacturing. This thesis aims to gain fundamental insights into melting behavior of different materials including single-crystal bimetallic core/shell alloy and intermetallic …

Additive Manufactured Ear Pinna For Spatial Cue Preservation In Custom Hearing Devices, Carlos Felipe Acosta Carrasco

Open Access Theses & Dissertations

Advancements in additive manufacturing/3D printing technologies has permitted the fabrication of intricate features such as the ones present in the human ear. The outer ear, also known as the pinna, allows for the spectral cues from incoming sound to be captured and identified. The hypothesis of the preservation of auditory localization and externalization relies on the fabrication of an ear pinna via additive manufacturing embedded into a headset for spectral cue preservation and hearing protection. Before exploring these custom circumaural hearing devices, a study on the fabrication process of AM pinnae was performed. The KEMAR system for acoustic research was …

Muse 1: Interactive Water Table, Sarah R. Higginbotham

Chancellor’s Honors Program Projects

No abstract provided.

Optimization Of An Advanced Aerogel Packaging Solution For Cold-Chain Biological Materials Handling, Aaron Michael Cook

Electronic Theses and Dissertations

The thermal performance of typical insulating materials is a limiting factor in the cost effectiveness of transporting temperature sensitive, biological materials, also known as cold chain bio-logistics. Biologicals that need to be maintained at near freezing or cryogenic temperatures rely on active refrigeration systems or passive solutions, such as dewars, gel packs, dry ice, urethane foam and/or extruded polystyrene. To ensure the packages arrive at its destination and at the desired temperature, costly overnight or expedited shipping is required. Hence, an aerogel based packaging solution is proposed as a possible solution for maintaining an acceptable internal temperature range with the …

Heat Transfer Interface To Graphitic Foam, Fang-Ming Lin

Master's Theses

The A Toroidal LHC ApparatuS (ATLAS) strip tracking detector is scheduled to be upgraded in 2025. The order of magnitude for the hit densities and the radiation damage are expected to increase. When radiation increases, the leakage current increases and the heat generated at the silicon trackers can lead to thermal runaway. Cooling is critical in these detectors.

In this study, a glassy graphitic foam was developed by AllComp Inc.~as a precursor to the adhesives (glues). Graphene\textsc{\char13}s highly anisotropic thermal properties result in high thermal conductivity in the planar direction, while it is low in the normal direction. In these …

Numerical Studies Of Turbulence Effects In Cross-Flow Ventilation, Mina Mohammadmirzaei

Master's Theses

Natural ventilation systems reduce a building’s utilization of energy in terms of electricity consumption and fossil fuel usage. Many factors including building shape, window style and configuration, and wind turbulence impact the efficacy of natural ventilation. In order to investigate the effect of turbulence on natural ventilation, twelve different conditions of a cross-flow ventilated room were studied numerically using computational fluid dynamics. Wind tunnel studies of tracer gases in a scale model were used to validate the numerical results. A comparison of twelve investigated cases shows that air circulation inside a natural ventilated room is only slightly affected by turbulence, …

Foot-Controlled Supernumerary Robotic Arm: Control Methods And Human Abilities, Zachary Joseph Doughtery

Graduate Theses - Mechanical Engineering

Supernumerary robotic limbs (SRLs) are extra robotic appendages that help a user with various tasks. A challenge with SRLs is how to operate them effectively. One solution is to use the foot to teleoperate the arm, freeing the person to use their arms for other tasks. However, unlike hand interfaces, it is not known how to create effective foot control for robotic teleoperation. A foot interface is developed for an experiment to compare position and rate control with the foot. Position control is shown to be more effective than rate control for 2D positioning tasks. Even if an effective control …

Foot Stress And Blood Flow Sensing Under High-Loading During Hip Surgery, Chris Cardenas, Esther Chen, Claire Kingston, Katie Paswaters, Brianna Rodebaugh

Mechanical Engineering

The PolyHIPS team was tasked with integrating sensors into Stryker’s hip arthroscopy boot that monitor blood flow and heel slip during hip surgery. During hip arthroscopy, the femur head is distracted from the acetabulum to create space in the joint for the surgeon to operate. This requires the use of up to 200 lbf. In order to maintain this space, the foot is held tightly in the boot. Complications can result from the foot being held too tightly in the boot during the procedure. The most common complication is neuropraxia, or temporary nerve damage. PolyHIPS proposes a solution that utilizes …