Digital Commons Network^™

A Numerical Simulation Optimizing Droplet Motion Driven By Electrowetting, Jake M. Lesinski

Master's Theses

A numerical simulation of electrowetting on a dielectric was performed in COMSOL to grant insight on various parameters that play a critical role in system performance. The specific system being simulated was the Open Drop experiment and the parameters being investigated were the applied voltage, contact angle at the advancing triple point, and droplet overlap onto neighboring actuated electrodes. These parameters were investigated with respect to their effect on droplet locomotion performance. This performance was quantified by the droplets velocity and the dielectrophortic (DEP) force’s magnitude; the DEP force was calculated from integration of the Maxwell Stress Tensor, however, the …

A Framework For Bim Model-Based Construction Cost Estimation, Michael Clark

Master's Theses

This thesis presents a framework to conduct a quantity take-off (QTO) and cost estimate within the Building Information Modeling (BIM) Environment. The product of this framework is a model-based cost estimating tool. The framework addresses the cost uncertainty associated with the detailed information defining BIM model element properties. This cost uncertainty is due to the lack of available tools that address detailed QTO and cost estimation using solely a BIM platform. In addition, cost estimators have little experience in leveraging and managing information within semantic-rich BIM models. Unmanaged BIM element parameters are considered a source of uncertainty in a model-based …

The Performance Cost Of Security, Lucy R. Bowen

Master's Theses

Historically, performance has been the most important feature when optimizing computer hardware. Modern processors are so highly optimized that every cycle of computation time matters. However, this practice of optimizing for performance at all costs has been called into question by new microarchitectural attacks, e.g. Meltdown and Spectre. Microarchitectural attacks exploit the effects of microarchitectural components or optimizations in order to leak data to an attacker. These attacks have caused processor manufacturers to introduce performance impacting mitigations in both software and silicon.

To investigate the performance impact of the various mitigations, a test suite of forty-seven different tests was created. …

Viewpoint Optimization For Autonomous Strawberry Harvesting With Deep Reinforcement Learning, Jonathon J. Sather

Master's Theses

Autonomous harvesting may provide a viable solution to mounting labor pressures in the United States' strawberry industry. However, due to bottlenecks in machine perception and economic viability, a profitable and commercially adopted strawberry harvesting system remains elusive. In this research, we explore the feasibility of using deep reinforcement learning to overcome these bottlenecks and develop a practical algorithm to address the sub-objective of viewpoint optimization, or the development of a control policy to direct a camera to favorable vantage points for autonomous harvesting. We evaluate the algorithm's performance in a custom, open-source simulated environment and observe affirmative results. Our trained …

Stationary Exercise Bicycle Instrumentation And Verification Of Opensim Pelvic Residual Loads In Seated Cycling, Bradley Robert Wash

Master's Theses

The study of cycling biomechanics typically requires measurement of pedal loads through force transducer instrumentation. However, analysis of seated cycling often necessitates the additional measurement of the loads exerted on the rider by the seat and handlebars. A stationary exercise bicycle was instrumented with two commercial six-axis force transducers at both the seat and handlebar locations via a custom designed mounting system. The system was tested by applying known forces and moments to the fixtures and proved capable of accurately measuring the loads. Additional data collected from cycling tests were compared to values from the literature to add supporting evidence …

Modeling Sensible Heat Driven Direct Contact Membrane Distillation Treatment Of Oilfield Produced Water, Tyler Gregory Dery

Master's Theses

A model was developed for predicting the performance of direct contact membrane distillation (DCMD) to evaluate the feasibility of using sensible heat to drive DCMD treatment of oilfield produced water. Algorithms for performance prediction of instantaneous and counter-current DCMD flow were developed. These algorithms used equation-based models of heat transfer, mass transfer, concentration polarization, and counter-current flow to predict performance of DCMD systems. The performance prediction model was validated against experimental data from the literature, and limitations to the accuracy of predictions were identified. The model was applied to evaluate performance sensitivity to nine operational parameters. The model was applied …

Evaluating Projections And Developing Projection Models For Daily Fantasy Basketball, Eric C. Evangelista

Master's Theses

Daily fantasy sports (DFS) has grown in popularity with millions of participants throughout the world. However, studies have shown that most profits from DFS contests are won by only a small percentage of players. This thesis addresses the challenges faced by DFS participants by evaluating sources that provide player projections for NBA DFS contests and by developing machine learning models that produce competitive player projections.

External sources are evaluated by constructing daily lineups based on the projections offered and evaluating those lineups in the context of all potential lineups, as well as those submitted by participants in competitive FanDuel DFS …

Field Emissions Of Methane And Nitrous Oxide From California Landfills, Alexandra D. Limpert

Master's Theses

Comprehensive and systematic aerial and field investigations were conducted at representative California landfills to quantify emissions of methane and nitrous oxide. Landfills are highly engineered; however, they are one of the largest anthropogenic sources of greenhouse gases, causing human health and safety concerns. Methane (CH₄) and nitrous oxide (N₂O) are significant greenhouse gases with high global warming potentials that are generated in a landfill environment.

For site selection, sites were evaluated based on waste in place, climate zone, faults and oil and gas operations, population density, cover conditions and percentage of cover types, age of waste, …

A Case Study Examining The Structure Of The Event Process At California Polytechnic State University, Ryan R. Baker

Master's Theses

The purpose of this study was to examine the structure of the event process on Cal Poly’s campus. An intrinsic case study method was used, and data were collected and analyzed using triangulation from three sources of information: documents, interviews, and participation research. Overall, the structure of the event management process on campus was found to be stable, but could use improvement. Cal Poly should consider establishing a specific, designated organization that would help centralize the event management process at Cal Poly. This organization could be in charge of training and updating event managers, approving events, monitoring volume of events …

The Effects Of Weld Thermal Cycles On Additively Manufactured 316l Stainless Steel, Hajime Yamanaka

Master's Theses

To address the size limitation of the powder bed fusion system in additive manufacturing, the welding properties of 316L stainless steel manufactured by SLM 125HL are investigated by conducting hot ductility test and nil strength temperature (NST) test with a physical thermal mechanical simulator, Gleeble. In this study, the print orientations (Zdirection and XY-direction) and the laser patterns (stripe and checker board) are studied. In NST test, the orientation showed a statistical significance in NST: Z-direction was 1384°C and XY-direction was 1400°C. In hot ductility test, all of ductility curves show similar behaviors: hardening region, recrystallization region, and liquation region. …

A Cubesat Orbital Test Platform For An Electrothermal Plasma Micro-Thruster, Sean L. Crowley

Master's Theses

As the viability and capability of CubeSats increases, a demand for propulsion systems is becoming apparent. The limitations put forth in the ``CubeSat Design Specifications" and the additional difficulties of low available Size, Weight and Power (SWaP) for propulsion systems aboard CubeSats have left a technological gap that many are trying to fill. One class of propulsion, micro-propulsion systems, fills this gap nicely as they generally have low size and weight with a reasonable amount of power draw. Many can function for reasonable lifetime scales utilizing pressure vessels under one atmosphere and less then 100 watt-hours of stored chemical energy …

Fifth Aeon – A.I Competition And Balancer, William M. Ritson

Master's Theses

Collectible Card Games (CCG) are one of the most popular types of games in both digital and physical space. Despite their popularity, there is a great deal of room for exploration into the application of artificial intelligence in order to enhance CCG gameplay and development. This paper presents Fifth Aeon a novel and open source CCG built to run in browsers and two A.I applications built upon Fifth Aeon. The first application is an artificial intelligence competition run on the Fifth Aeon game. The second is an automatic balancing system capable of helping a designer create new cards that do …

Study Of Paper Microbial Fuel Cells For Use In On-Site Wastewater Testing, William A. Tolmasoff

Master's Theses

This study demonstrated a technique for fabricating simple, low-cost Paper Microbial fuel cells (PMFC’s) in the model of a previous study to, for the first time, produce voltage from wastewater effluent. The PMFC’s were created by stacking and gluing the main components of an MFC together: reservoir layer; anode; cation exchange membrane (CEM); air cathode. A wax printer was used to create the hydrophobic borders of the PMFC’s on filter paper, and graphite paint was applied to the paper to create the anode. The CEM’s considered were filter paper, wax, and Nafion, with Nafion being the most efficient. Finally, the …

Analysis Of The Effects Of Adaptive Ramp Metering On Measures Of Efficiency With A Proposed Framework For Safety Evaluation, Jacky Loh

Master's Theses

Adaptive ramp metering (ARM) is a widely popular intelligent transportation system (ITS) tool that boasts the ability to reduce congestion and streamline traffic flow during peak hour periods while maintaining a lower implementation cost than traditional methods such as freeway widening. This thesis explores the effectiveness of ARM implementation on an 18 mile segment of the Interstate 80 (I-80) corridor in the Bay Area residing in northern California. Smaller segments of this particular segment were analyzed to determine the effective length of ARM on efficiency at various lengths originating from a known bottleneck location. Efficiency values were also compared against …

Atomic Oxygen Effects On Particulate Contamination And Short Beam Strength Of Carbon Composites, Marlee K. Litzinger

Master's Theses

In order to design a successful space system, the unique challenges of the space environment it will operate in must be considered during the design process. Atomic oxygen (AO) is a detrimental environmental effect found in Low Earth Orbit (LEO) that affects spacecraft surfaces by oxidizing and eroding material over time, particularly polymers. Carbon fiber/epoxy composites are a commonly used spacecraft material affected by AO exposure. Carbon composites are used as a structural material, such as on solar panels; their large surface area therefore is a potential contamination source to sensitive components. The Space Environments and Testing Lab at California …

Effects Of Corrugations On Stiffness Properties Of Composite Beams For Structural Applications, Jane Xiao

Master's Theses

Composites have high strength-to-weight ratios, which is particularly desired for applications with weight restrictions. Common composite materials such as carbon fiber reinforced plastic (CF) and fiber glass reinforced plastic (FG) were used in this research. While composite materials possess high stiffness and strength properties, the stiffness of composite laminates may be maximized by changing the geometry. By adding corrugations, the flexural stiffness is increased in one direction compared to the stiffness of a flat part with the same amount of material. Thus, stiffness increases without a change in weight. The primary goal of this research was to investigate the stiffness …

Carbonate Chemistry Characterization In A Low-Inflow Estuary With Recent Seagrass Loss, Jolie Higgins

Master's Theses

Estuaries are dynamic environments that are strongly affected by natural variability, as well as direct and indirect anthropogenic impacts. A better understanding of the drivers of carbon fluxes and biogeochemical variability in estuarine systems is needed, particularly with the increasing threat of ocean acidification. Morro Bay in Central California is a small nationally protected estuary, with seasonally low freshwater inputs. Since 2007, the bay has experienced a significant loss of native seagrass, Zostera marina, which is an important component of the marine ecosystem. Because seagrass photosynthesis decreases carbon dioxide and increases oxygen in the water column, the loss of seagrass …

A Predictive Modeling Approach For Assessing Seismic Soil Liquefaction Potential Using Cpt Data, Jonathan Paul Schmidt

Master's Theses

Soil liquefaction, or loss of strength due to excess pore water pressures generated during dynamic loading, is a main cause of damage during earthquakes. When a soil liquefies (referred to as triggering), it may lose its ability to support overlying structures, deform vertically or laterally, or cause buoyant uplift of buried utilities. Empirical liquefaction models, used to predict liquefaction potential based upon in-situ soil index property measurements and anticipated level of seismic loading, are the standard of practice for assessing liquefaction triggering. However, many current models do not incorporate predictor variable uncertainty or do so in a limited fashion. Additionally, …

A Homegrown Dsmc-Pic Model For Electric Propulsion, Dominic Charles Lunde

Master's Theses

Powering spacecraft with electric propulsion is becoming more common, especially in CubeSat-class satellites. On account of the risk of spacecraft interactions, it is important to have robust analysis and modeling tools of electric propulsion engines, particularly of the plasma plume. The Navier-Stokes equations used in classic continuum computational fluid dynamics do not apply to the rarefied plasma, and therefore another method must be used to model the flow. A good solution is to use the DSMC method, which uses a combination of particle modeling and statistical methods for modeling the simulated molecules. A DSMC simulation known as SINATRA has been …

A 3-Dimensional In Silico Test Bed For Radiofrequency Ablation Catheter Design Evaluation And Optimization, Carolyn Teng

Master's Theses

Atrial fibrillation (AF) is the disordered activation of the atrial myocardium, which is a major cause of stroke. Currently, the most effective, minimally traumatic treatment for AF is percutaneous catheter ablation to isolate arrhythmogenic areas from the rest of the atrium. The standard in vitro evaluation of ablation catheters through lesion studies is a resource intensive effort due to tissue variability and visual measurement methods, necessitating large sample sizes and multiple prototype builds. A computational test bed for ablation catheter evaluation was built in SolidWorks® using the morphology and dimensions of the left atrium adjacent structures. From this geometry, the …

Dynamic Response Validation Of Cubesats Through Testing And Finite Element Analysis, Peter Rivera

Master's Theses

During a rocket launch, satellites withstand large dynamic forces due to vibrations that are transmitted from the launch vehicle. As such, they must undergo testing to ensure that their function is not impaired by such forces. CubeSats are cost-effective nanosatellites, and like their larger counterparts, undergo dynamic testing for launch qualification. While dynamic analysis can done on a CubeSat alone, other assembly constituents also affect the response, and including them in the analysis can provide insight on the true dynamic behavior of CubeSats. To show this, the work presented here recreates a vibration test setup using Finite Element Analysis (FEA) …

Saponin Removal From Quinoa By Abrasion Processing, Luke Lundberg

Master's Theses

Quinoa is coated with a thin layer of saponins, glycosylated triterpenoids, that produce a bitter flavor when consumed. The average saponin content in commercial varietals from Bolivia average around 2.7% saponins and organoleptic testing shows the threshold for noticing a bitter flavor is below 0.12% (Medina-Meza et al., 2016). Current industrial processing methods use a combination of abrasion and turbulent water flow to remove saponin. This study will address the following research question: How will grain-to-grain and grain-to-surface abrasion affect the processing time to remove saponin from quinoa? In particular, can effective saponin removal be achieved in less than 10 …

Observations Of The Copenhagen Networks Study, Michael A. Cantrell

Master's Theses

Attribute-rich longitudinal datasets of any kind are extremely rare. In 2012 and 2013, the SensibleDTU project created such a dataset using approximately 1,000 university students. Since then, a large number of studies have been performed using this dataset to ask various questions about social dynamics. This thesis delves into this dataset in an effort to explore previously unanswered questions. First, we define and identify social encounters in order to ask questions about face-to-face interaction networks. Next, we isolate students who send and receive disproportionately high numbers of phone calls and text messages to see how these groups compare to the …

Compact Rake Boundary Layer Data System Module, Nathan Jeffry Hoyt

Master's Theses

This Thesis describes the design, assembly, programming, and evaluation of the BLDS-M-RAKE, the newest addition to the family of devices called the Boundary Layer Data System (BLDS). The BLDS-M-RAKE is a continuation of the BLDS-M series of devices, a modular approach with updated electronics for boundary layer measurements. The BLDS-M-RAKE records data from a number of sensors, intended to be routed to an array of probes, or rake. Through preliminary testing, a new flexible manifold design from molded silicone and the hardware used on the RFduino development boards from the BLDS-M proof-of-concept modules were validated for use in the final …

Development Of A Model And Imbalance Detection System For The Cal Poly Wind Turbine, Ryan Miki Takatsuka

Master's Theses

This thesis develops a model of the Cal Poly Wind Turbine that is used to determine if there is an imbalance in the turbine rotor. A theoretical model is derived to estimate the expected vibrations when there is an imbalance in the rotor. Vibration and acceleration data are collected from the turbine tower during operation to confirm the model is useful and accurate for determining imbalances in the turbine.

Digital signal processing techniques for analyzing the vibration data are explored and tested with simulation data. This includes frequency shifts, lock-in amplifiers, phase-locked loops, discrete Fourier transforms, and decimation filters. The …

Snoring: A Noise Defect Prediction Datasets, Aalok Ahluwalia

Master's Theses

Defect prediction aims at identifying software artifacts that are likely to exhibit a defect. The main purpose of defect prediction is to reduce the cost of testing and code review, by letting developers focus on specific artifacts. Several researchers have worked on improving the accuracy of defect estimation models using techniques such as tuning, re-balancing, or feature selection. Ultimately, the reliability of a prediction model depends on the quality of the dataset. Therefore effort has been spent in identifying sources of noise in the datasets, and how to deal with them, including defect misclassification and defect origin. A key component …

Transmission Probability Of Embolic Debris Through The Aortic Arch And Daughter Vessels During A Transcatheter Aortic Valve Replacement Procedure, Jessica Lena Wirth

Master's Theses

Cerebral ischemia leading to an ischemic stroke is a possible complication of a transcatheter aortic valve replacement (TAVR) procedure. This is because embolic debris can become dislodged and travel through the aortic arch, where they either continue to the descending aorta and join the systemic circulation or travel into the cerebral vasculature through the three daughter vessels that branch off the top of the aortic arch. These three vessels are the brachiocephalic artery, the left subclavian artery, and the left common carotid artery. These three vessels lead either directly or indirectly to the cerebral vasculature, where the diameter of vessels …

Sidewalks To Nowhere: A Tool To Prioritize Pedestrian Improvements, Ho Yan Lai

Master's Theses

Walkability as a concept that captures the ability to walk from one place to another has multiple dimensions. Between traversability to being a proxy for better urban places, there are also numerous measurements of walkability that attempts to quantify certain or all aspects of walkability. It is, however, unclear, through a review of available literature, how these measurements of walkability relate to each other statistically. This methodology focuses on generating a framework for analysts to evaluate and prioritize pedestrian infrastructure. WalkScore™ (WS), HCM Pedestrian Level of Service (PLOS), Average Nodal Degree (AND), and Intersection Density are the four metrics selected …

In-Plane Cyclic Behavior Of A Steel Mesh Reinforced Cob Wall, Julia Fremuth Sargent

Master's Theses

This thesis presents the results from in-plane cyclic testing of a reinforced cob wall. Cob is an earthen building material composed of sand, clay, straw and water. Cob is typically constructed with no steel reinforcement; however, the California Building Code requires reinforcement in all buildings for resisting seismic forces. The purpose of this thesis is to provide additional technical data to integrate cob into the building code.

Test results are reported for a 7’ x 8’ x 14” wall with two layers of welded wire steel reinforcement constructed on a reinforced concrete foundation. In-plane cyclic loading was performed on the …

A Paper-Based Elisa Device For The Rapid Detection Of Ischemic Stroke, Andrea Elisabeth Larsen

Master's Theses

Diagnosing an ischemic stroke quickly and accurately is essential for appropriate treatment and results in more effective management of the stroke, leading to better patient outcomes. Specifically, the determination of ischemic versus hemorrhagic stroke leads to critically different treatment paths, which would be potentially fatal if administered incorrectly. Currently, ischemic strokes are diagnosed through a series of tests, including a physical examination, CT scans, and a panel of blood tests to exclude hemorrhagic stroke or other similarly presenting conditions, in order to administer tPA (the main treatment) within the three hour window.

The discovery of biomarkers, molecules which are upregulated …