Digital Commons Network^™

A Modified Multiphase Boost Converter With Reduced Input Current Ripple: Split Inductance And Capacitance Configuration, Zoe M. Hay

Master's Theses

This thesis presents the simulation, design, and hardware implementation of a modified multiphase boost converter. Converter design must consider noise imposed on input and output nodes which connect to and influence the operation of other devices. Excessive noise introduces EMI which can damage sensitive circuits or impede their operation. High ripple current degrades battery lifetime and reduces operating efficiency in connected systems such as PV arrays. Converters with high ripple current also experience greater peak conduction loss and require larger components. A two-phase implementation of a modified boost converter demonstrates the input current filtering benefits of the modified topology with …

Design And Verification Of A Labview Automated Antenna Radiation Pattern Measurement System, Dylan C. Bloom

Master's Theses

In 2014, Toyon Research Corporation donated a 6’x6’x8’ anechoic chamber to the Cal Poly EE department to advance student education in the areas of antennas and wireless communications. An anechoic chamber is a room designed to suppress electromagnetic radiation reflections so that accurate measurement of radio frequency (RF) systems such as wireless radios and antennas can take place. Despite the fact that Cal Poly already has a larger anechoic chamber, primarily used for antenna characterization, it is the purpose of this project to design, code, and equip the new chamber so that it performs at least as good, or better …

Bird Abundance At Bird Feeders In Response To Temperature, Wind Speed And Precipitation During The Winter Season, Siddhant Kahal

Master's Theses

The goal of this project is to explore how 23 different bird species respond to 3 climatic attributes. These attributes are lower than average temperatures, wind speed and precipitation level. Information about the bird species and all of the data associated with them is provided by Project FeederWatch (PFW). This is a citizen based survey study that provides key information about bird species abundance through the use of backyard and community feeders. The study volunteers from across the United States and Canada monitor these bird feeders and note important information about the species such as the number of individuals seen. …

Evaluation Of Electrochemical And Laser Polishing Of Selectively Lasermelted 316l Stainless Steel, Julian R. Lohser

Master's Theses

Selective laser melting has shown incredible growth as a metallic additive manufacturing process in recent years. While it does provide many solutions and new ways to approach challenges, it does not come without issues of its own, namely, surface roughness. In the as-printed state, the surface roughness of selectively laser melted parts is unacceptable for use in engineering applications. Additionally, selective laser melting is used to produce complex geometries with hard to reach features, preventing conventional mechanical polishing from being successful. Therefore, it is necessary to evaluate non-mechanical polishing processes as treatments for surface roughness. In this study, electrochemical and …

The Gods Have Taken Thought For Them: Syncretic Animal Symbolism In Medieval European Magic, Solange Nicole Kiehlbauch

Master's Theses

This thesis investigates syncretic animal symbolism within medieval European occult systems. The major question that this work seeks to answer is: what does the ubiquity and importance of magical animals and animal magic reveal about overarching medieval perceptions of the world? In response, I utilize the emerging subfield of Animal History as a theoretical framework to draw attention to an understudied yet highly relevant aspect of occult theory and practice. This work argues that medieval Europeans lived in a fundamentally “enchanted” world compared to our modern age, where the permeable boundaries between physical and spiritual planes imbued nature and its …

Finite-Difference Modeling Of The Batch Process Smoldering Combustion Of Wastewater, Laura H. Kawashiri

Master's Theses

A MATLAB model was developed for the smoldering combustion of wastewater in the context of a decentralized residential wastewater treatment appliance. Data from a batch process sewage smoldering experiment was simulated using implicit finite-difference approximations, assuming one-dimensional transient conductive heat transfer. The time-dependent temperature profiles within the column represented the main parameters of interest and were used to verify recoverable heat energy estimations. Given that the modeling method used for this thesis represents a unique approach, the assumptions and limitations of this model are thoroughly described in the context of reproducing results for other smoldering setups. A lack of convergence …

Polycommit: Building Better Habits Through Gamification, Elliot Fiske

Master's Theses

Computer-assisted learning is older than Turing machines, and constantly evolves as technology improves. While some teachers are resistant to using technology in the classroom, “e-learning” techniques are becoming more common in almost every school, from K-12 to universities. As technology becomes more widespread, it becomes crucial to examine the various methodologies of computer-assisted learning and find the techniques that are most effective.

This paper explores the effectiveness of one such methodology, spaced repetition. This technique applies to homework assignments available to students online. We include an exploration of several existing apps that use this technique, and introduce our own novel …

Hydrologic Response To Conifer Removal And Upslope Harvest In An Encroached Montane Meadow, Noël C. Fie

Master's Theses

Meadows are crucial components to larger river watersheds because of their unique hydrologic and ecological functions. Due to climate change, over grazing, and fire suppression, conifer encroachment into meadows has accelerated. In some western regions, nearly half of all meadow habitat has been loss due to conifer encroachment. Restoration of these hydrologic systems requires tree removal. Many studies exist that address the issue of conifer encroachment in montane meadows, however, few studies focus on the role that conifer removal plays on the encroaching meadow. Furthermore, few studies exist that document the hydrologic change from conifer removal and further restoration steps, …

Using Gaze Tracking To Tackle Duplicate Questions On Community Based Question Answering Websites: A Case Study Of Ifixit, Pankti Gandhi

Master's Theses

The number of unanswered questions on Community based Question Answering (CQA) websites has increased significantly due to the rising number of duplicate questions. This is a serious problem, one that could lead to the decline of such beneficial websites.

This thesis presents novel avenues that use gaze tracking technology and behavioral testing to tackle this problem. Based on prior studies on web search behaviors, we assumed that adding contextual information (snippets) to proposed related questions displayed on the `Ask a Question' page of the CQA website iFixit would improve the asker experience and reduce their tendency to post a new …

Utilizing Permanent On-Board Water Storage For Efficient Deep Space Radiation Shielding, Nathan Ryan Gehrke

Master's Theses

As space technologies continue to develop rapidly, there is a common desire to launch astronauts beyond the ISS to return to the Moon and put human footsteps on Mars. One of the largest hurdles that still needs to be addressed is the protection of astronauts from the radiation environment seen in deep space. The most effective way to defend against radiation is increasing the thickness of the shield, however this is limited by strict mass requirements. In order to increase the thickness of the shield, it is beneficial to make mission critical items double as shielding material.

The human rated …

Acceleration Of Jaccard's Index Algorithm For Training To Tag Damage On Post-Earthquake Images, Kyle John Mulligan

Master's Theses

There are currently different efforts to use Supervised Neural Networks (NN) to automatically label damages on images of above ground infrastructure (buildings made of concrete) taken after an earthquake. The goal of the supervised NN is to classify raw input data according to the patterns learned from an input training set. This input training data set is usually supplied by experts in the field, and in the case of this project, structural engineers carefully and mostly manually label these images for different types of damage. The level of expertise of the professionals labeling the training set varies widely, and some …

Exploring The Concept Of A Deep Space Solar-Powered Small Spacecraft, Kian Guillaume Crowley

Master's Theses

New Horizons, Voyager 1 & 2, and Pioneer 10 & 11 are the only spacecraft to ever venture past Pluto and provide information about space at those large distances. These spacecraft were very expensive and primarily designed to study planets during gravitational assist maneuvers. They were not designed to explore space past Pluto and their study of this environment is at best a secondary mission. These spacecraft rely on radioisotope thermoelectric generators (RTGs) to provide power, an expensive yet necessary approach to generating sufficient power. With Cubesats graduating to interplanetary capabilities, such as the Mars-bound MarCO spacecraft, matching the modest …

Improving Introductory Computer Science Education With Draco, Mike Dongyub Ryu

Master's Theses

Today, many introductory computer science courses rely heavily on a specific programming language to convey fundamental programming concepts. For beginning students, the cognitive capacity required to operate with the syntactic forms of this language may overwhelm their ability to formulate a solution to a program.

We recognize that the introductory computer science courses can be more effective if they convey fundamental concepts without requiring the students to focus on the syntax of a programming language. To achieve this, we propose a new teaching method based on the Design Recipe and Code Outlining (DRaCO) processes. Our new pedagogy capitalizes on the …

Pink And Dude Chefs: Effectiveness Of An After-School Nutrition Knowledge And Culinary Skills Program For Middle School Students To Increase Fruit And Vegetable Consumption, Alyssa S. Vaziri

Master's Theses

The rate of overweight and obesity among adolescents aged 12-19 years has more than tripled since 1980, and disproportionately impacts low-income and marginalized populations. Reduction in adolescent obesity rates may result in decreased health risks, decrease healthcare costs, and increased quality of life. Effective intervention methods for adolescent participants have incorporated nutrition knowledge and culinary skill building into afterschool programs. This study examines whether building knowledge, skills, and confidence through a culinary intervention can improve adolescent participants’ choices of healthful foods through increased fruit and vegetable intake.

Pink and Dude Chefs (PDC) is an afterschool nutrition education and culinary skills …

Dynamics Simulation And Optimal Control Of A Multiple-Input And Multiple-Output Balancing Cube, Felix K. Haimerl

Master's Theses

This thesis document outlines the development of a multibody dynamics simulation of an actively stabilized multiple-input, multiple-output, coupled, balancing cube and the process of verifying the results by implementing the control algorithm in hardware. A non-linear simulation of the system was created in Simscape and used to develop a Linear Quadratic Gaussian control algorithm. To implement this algorithm in actual hardware, the system was first designed, manufactured, and assembled. The structure of the cube and the reaction wheels were milled from aluminum. DC brushless motors were installed into the mechanical system. In terms of electronics, a processor, orientation sensor, motor …

Neuro-Silicon Interface Of A Hirudo Medicinalis Retzius Cell Integrated With Field Effect Transistor, Kurt Christian Sjoberg

Master's Theses

The focus of this thesis was to measure the intracellular voltage of a living neural cell using a silicon transistor. The coupling of neurological tissues with silicon devices is of interest to the fields of neurology, neuroscience, electrophysiology and cellular biology. In previous work by Peter Fromherz, single neurons were successfully coupled to transistors [1]. This thesis aims to show proof of concept of the fabrication of a simple neuro-silicon interface using wafer processing methods currently available at Cal Poly. The types of transistors and cells used, the methods for dissecting and preparing the cells, the electrophysiology methods for validating …

Modeling The Spatially Varying Point Spread Function Of The Kirkpatrick-Baez Optic, Nathan Adelman

Master's Theses

Lawrence Livermore National Laboratory's (LLNL) National Ignition Facility (NIF) uses a variety of diagnostics and image capturing optics for collecting data in High Energy Density Physics (HEDP) experiments. However, every image capturing system causes blurring and degradation of the images captured. This degradation can be mathematically described through a camera system's Point Spread Function (PSF), and can be reversed if the system's PSF is known. This is deconvolution, also called image restoration. Many PSFs can be determined experimentally by imaging a point source, which is a light emitting object that appears infinitesimally small to the camera. However, NIF's Kirkpatrick-Baez Optic …

Influencing Exploration In Actor-Critic Reinforcement Learning Algorithms, Andrew R. Gough

Master's Theses

Reinforcement Learning (RL) is a subset of machine learning primarily concerned with goal-directed learning and optimal decision making. RL agents learn based on a reward signal discovered from trial and error in complex, uncertain environments with the goal of maximizing positive reward signals. RL approaches need to scale up as they are applied to more complex environments with extremely large state spaces. Inefficient exploration methods cannot sufficiently explore complex environments in a reasonable amount of time, and optimal policies will be unrealized resulting in RL agents failing to solve an environment.

This thesis proposes a novel variant of the Actor-Advantage …

Catheter Localization Utilizing A Sensor-Enabled Guidewire: Design Of A Proof-Of-Concept System, Adam Edward Evard

Master's Theses

The purpose of this thesis project was to develop a proof-of-concept system for tracking the tip of a catheter without an embedded electromagnetic sensor by utilizing a sensor enabled guidewire. The motivation for the project was a reduction fluoroscopy radiation dose for clinicians in the interventional cardiology lab and the extension of navigation technology to be used with a wider variety of interventional devices through the implementation of expanded capabilities of the Abbott MediGuide system. The focus of the project was on the development of a proof-of-concept system capable of using an external device to track relative guidewire and catheter …

Characterization Of Arterial Flow For Junctional Bleeding Control, Nick Bosio

Master's Theses

This study investigated reducing volumetric flowrate under steady flow conditions by varying lengths of compression with constant cross-sectional area and varying cross-sectional area reduction with constant length in order to better understand how to control junctional hemorrhaging. The hypotheses of this study were that length reduction will have little effect on volumetric flowrate and that cross-sectional area reduction would need to be approximately 80 percent in order to obtain bleeding control. The study found that length reduction has little effect on changing the flowrate. However, in order to obtain at least 80 percent reduction in flow, the area needs to …

Thermal Modelling And Validation Of Heat Profiles In An Rf Plasma Micro-Thruster, Alec Sean Henken

Master's Theses

The need and demand for propulsion devices on nanosatellites has grown over the last decade due to interest in expanding nanosatellite mission abilities, such as attitude control, station-keeping, and collision avoidance. One potential micro-propulsion device suitable for nanosatellites is an electrothermal plasma thruster called Pocket Rocket. Pocket Rocket is a low-power, low-cost propulsion platform specifically designed for use in nanosatellites such as CubeSats. Due to difficulties associated with integrating propulsion devices onto spacecraft such as volume constraints and heat dissipation limitations, a characterization of the heat generation and heat transfer properties of Pocket Rocket is necessary. Several heat-transfer models of …

Validation Of A 1d Algorithm That Measures Pulse Wave Velocity To Estimate Compliance In Blood Vessels, James Leung

Master's Theses

The purpose of this research is to determine if it is possible to validate the new 1D method for measuring pulse wave velocity in the aorta in vivo and estimate compliance. Arterial pressure and blood flow characterize the traveling of blood from the heart to the arterial system and have played a significant role in the evaluation of cardiovascular diseases. Blood vessel distensibility can give some information on the evolution of cardiovascular disease. A patient’s aorta cannot be explanted to measure compliance; therefore we are using a flow phantom model to validate the 1D pulse wave velocity technique to estimate …

Automated Pruning Of Greenhouse Indeterminate Tomato Plants, Joey M. Angeja

Master's Theses

Pruning of indeterminate tomato plants is vital for a profitable yield and it still remains a manual process. There has been research in automated pruning of grapevines, trees, and other plants, but tomato plants have yet to be explored. Wage increases are contributing to the depleting profits of greenhouse tomato farmers. Rises in population are the driving force behind the need for efficient growing techniques. The major contribution of this thesis is a computer vision algorithm for detecting greenhouse tomato pruning points without the use of depth sensors. Given an up-close 2-D image of a tomato stem with the background …

Comparative Analysis Of Physiological Measurements And Environmental Metrics On Predicting Heat Stress Related Events, Mckenzie Lee Barlow

Master's Theses

Exposure to high heat and humidity can lead to serious health risks, including heat exhaustion and heat stroke. Wet Bulb Globe Temperature (WBGT) and heat index have historically been used to predict heat stress events, but individualized factors are not included in the measurement. It has been shown that there is a relationship between cardiovascular measurements and heat stress, which could be used to measure heat stress risk on an individual level. Research has been done to find relationships between cardiovascular metrics in a workplace environment, however the study did not include the use of a controlled environment as a …

Investigation On The Dissociative Photoionization Mechanism Of Furfural, Investigation Of The Absolute Photoionization Cross Sections Of Three Potential Propargylic Fuels, And Ab Initio Analysis On Potential Superbases Of Several Hyperlithiated Species: Li3f2o And Li3f2(Oh)N (N = 1, 2, 3), Matthew Winfough

Master's Theses

This thesis presents the study photoionization cross sections of three different propargylic biofuels; dipropargyl ether, propargyl alcohol, and propargylamine, in chlorine radical-initiated combustion experiments at the Chemical Dynamics Beamline (9.0.2) at the Advanced Light Source of the Ernest Orlando Berkeley National Laboratory in Berkeley, California. Additionally, the unimolecular dissociative photoionization mechanism of furfural was studied using photoelectron photoionization coincidence (PEPICO) spectroscopy at the vacuum ultraviolet beamline at the Swiss Light Source of the Paul Scherrer Institut in Villigen, Switzerland. Dissociation products and mechanisms for furfural were identified over a photon energy range of 10.9 to 14.5 eV. Lastly, a study …

The Dissolution Of Diatoms In Marine Microbial Mats, Almariet Palm

Master's Theses

Microbial mats are self-contained organosedimentary ecosystems that played an important role in the evolution of early life on Earth. Understanding the conditions of their formation and preservation in the fossil record could provide valuable insights into microbe-mineral interactions and paleoenvironmental reconstruction. Diatoms are found at the surface of extant microbial mats, but their frustules are not observed at depth and rarely in fossil microbialites, which suggest their frustules dissolve. The objective of this study is to investigate the role of cyanobacterial photosynthesis, which locally elevates pH, in the dissolution of diatoms frustules. Field data and laboratory studies determined the effect …

Damage Detection In Textile Composites Via Piezoelectric Admittance Methods, Sazid Irfan Ahmed

Master's Theses

Structural health monitoring of aerospace structures is becoming vital as lightweight composite materials are increasingly used in aero-structures. Composites have various types of failure modes, which make it even more important to identify fault or damage compared to isotropic materials. Therefore, on-site health monitoring is one of the most preferred methodologies for detecting internal crack or damage at its initial stage to enhance operating safety and reduce repair cost. Recently, piezoelectric transducers are on high demand for on-site health monitoring because of its high bandwidth sensitivity. They simultaneously perform as actuators and sensors and embedded in the structure for real …

Barriers To Dental Care For Children With Autism Spectrum Disorders, Nidhi Taneja

Master's Theses

Aims: To investigate barriers to dental care for children with autism spectrum disorder (ASD) from dentists’ and caregivers’ perspective.

Methods: This paper documents two cross sectional surveys of barriers to treating children with ASD. 109 general dentists were surveyed at a national conference in study 1, of whom about 74% reported treating children with ASD. In study 2, 83 caregivers were surveyed in hospital clinics, 46 of whom had a child with ASD, and 37 had children without ASD, and acted as a control group. Results: The most commonly endorsed barriers perceived by general dentists were: lack of guidelines …

Security Dilemma In U.S.-China Relations: A Non-Traditional Security Studies Perspective, Jessica Tran

Master's Theses

Since Former President Barack Obama’s announcement of the Pacific Pivot in 2011, the security dilemma in U.S.-China relations have worsened considerably. Under President Donald Trump’s administration, the shifting of U.S. military focus to the Asia-Pacific region is expected to continue. As the U.S. moves forward with increasing its military presence in the Pacific to counter a perceived “aggressive” China, it may lead to serious consequences. This thesis presents the argument that China’s conception of national security includes the defense of the state from both foreign and domestic threats. Therefore, China’s military developments and policies are not strictly in response to …

Testimonies Of Identity And Intimate Partner Violence, Jamie Berrien

Master's Theses

Intimate Partner Violence (IPV) is an epidemic that has impacted millions of women in our country. IPV is found in every community and impacts women from all races, ethnicities, religion, background, and socio-economic status. Yet, research shows that women in the United States who are not a part of the dominant culture experience IPV at a much higher rate than white women. This study focuses on the sacred testimonies of six women who have experienced IPV, as well as an analysis of the women's identities and other forms of oppression which impacts her experiences and survival of the violence.