Digital Commons Network^™

Analysis Of The Tidal Range In The Sacramento San Joaquin Delta From 1857 To Present, Elena Szlemp

Master's Theses

The Sacramento San Joaquin Delta has been highly altered by human activity since the mid-1800s from mining, agriculture, dredging, and urbanization. Did the resulting modifications to channel width, depth, and length alter tidal range in the Sacramento San Joaquin Delta?

In this study, archival tidal records were evaluated at many stations throughout the San Francisco Bay and Delta, with a focus on San Francisco, Rio Vista, Sacramento, and Stockton daily, monthly, and annual tidal ranges. Monthly and seasonally averaged tidal ranges were analyzed to determine seasonal changes. In addition, tidal range was compared to daily Delta discharge to consider the …

Investigation Of Experimental Variation Of Bovine Sphingomyelin As A Novel Ingredient For Ultraviolet Protection, Esther Chen

Master's Theses

Skin cancer is a prevalent disease that globally affects 2-3 million people per year [1]. This number is expected to grow tenfold as depletion of the ozone layer contributes to harsher rays reaching Earth’s surface [2]. A common way to protect against those ultraviolet waves is to apply sunscreen, however, recent reports call into question the safety of some active ingredients as they can enter through the skin into the bloodstream [3]. This thesis aims to investigate an alternative solution that uses bovine sphingomyelin (BSM) as photoprotective solution against UV irradiation.

In order to evaluate the effectiveness of BSM against …

Surface Modifications Of Reverse Osmosis Membranes For Removal Of Bromide And Reduction Of Fouling, Joseph Seo

Master's Theses

Reverse osmosis (RO) is widely used for water reuse and desalination. Although RO membranes are known for their high salt rejection and practical permeate flux, their performance can be impaired by fouling, and their removal of some disinfection byproducts and their precursors (e.g., bromide, N-Nitrosodimethylamine [NDMA]) does not meet drinking water standards. RO membrane modifications have been widely studied to overcome these limitations. In this research, RO membranes were grafted with cationic polymers to induce a positive charge on the RO membrane surface. This modification aimed at enhancing the rejection of negatively charged bromide ions by removing them from solution …

A Study Of The Design Of Adaptive Camber Winglets, Justin J. Rosescu

Master's Theses

A numerical study was conducted to determine the effect of changing the camber of a winglet on the efficiency of a wing in two distinct flight conditions. Camber was altered via a simple plain flap deflection in the winglet, which produced a constant camber change over the winglet span. Hinge points were located at 20%, 50% and 80% of the chord and the trailing edge was deflected between -5° and +5°. Analysis was performed using a combination of three-dimensional vortex lattice method and two-dimensional panel method to obtain aerodynamic forces for the entire wing, based on different winglet camber configurations. …

A Floristic Study Of The Cal Poly Swanton Pacific Ranch And A New Combination In Sanicula Crassicaulis (Apiaceae), Sanicula Crassicaulis Var. Nudicaulis, Reed J. Kenny

Master's Theses

Globally we are experiencing a biodiversity crisis and potentially a sixth mass extinction event. Plant specimens are one of the best, most concrete records of biodiversity that we can create. Despite this, the rate of plant collecting has declined steeply since World War II. Now more than ever, plant collections are vital, both for the purpose of quantifying the plant biodiversity in an area and for discovering previously unrecognized diversity.

In Chapter 1, we conducted a floristic survey of the Cal Poly Swanton Pacific Ranch. The Swanton Pacific Ranch (SPR) is located north of the small town of Davenport California, …

Attacking Computer Vision Models Using Occlusion Analysis To Create Physically Robust Adversarial Images, Jacobsen Loh

Master's Theses

Self-driving cars rely on their sense of sight to function effectively in chaotic and uncontrolled environments. Thanks to recent developments in computer vision, specifically convolutional neural networks, autonomous vehicles have developed the ability to see at or above human-level capabilities, which in turn has allowed for rapid advances in self-driving cars. Unfortunately, much like humans being confused by simple optical illusions, convolutional neural networks are susceptible to simple adversarial inputs. As there is no overlap between the optical illusions that fool humans and the adversarial examples that threaten convolutional neural networks, little is understood as to why these adversarial examples …

Pocket Rocket: A 1u+ Propulsion System Design To Enhance Cubesat Capabilities, James M. Harper

Master's Theses

The research presented provides an overview of a 1U+ form factor propulsion system design developed for the Cal Poly CubeSat Laboratory (CPCL). This design utilizes a Radiofrequency Electrothermal Thruster (RFET) called Pocket Rocket that can generate 9.30 m/s of delta-V with argon, and 20.2 ± 3 m/s of delta-V with xenon. Due to the demand for advanced mission capabilities in the CubeSat form factor, a need for micro-propulsion systems that can generate between 1 – 1500 m/s of delta-V are necessary.

By 2019, Pocket Rocket had been developed to a Technology Readiness Level (TRL) of 5 and ground tested in …

Host Plant Resistance In Strawberries To Anthracnose And Colonization Of Crown And Root Tissue By Verticillium Dahliae And Macrophomina Phaseolina, Omar A. Gonzalez-Benitez

Master's Theses

Strawberries are considered an important crop in California where in 2018 it was in the top 5 valued fruit and vegetable commodities valued at $2.84 billion accounting for 88% of the total U.S. production. Strawberry production can be severely impacted by soilborne pathogens that can affect strawberry roots, crowns and leaves which can result in plant mortality. As much as 50 to 60% mortality can occur in one field. Pathogens responsible for such losses include Colletotrichum acutatum (syn.C. nymphaeae), Macrophomina phaseolina and Verticillium dahliae. With the phaseout of methyl bromide, host resistance and an understanding of host-pathogen interactions …

The Strawberry Rhizosphere Microbiome: Role On Plant Health And Nutrition, Eric Michael Boyd

Master's Theses

Microbial-root associations are important to help plants cope with abiotic and biotic stressors. Managing these interactions offers an opportunity for improving the efficiency and sustainability of agricultural production. By characterizing the bacterial and archaeal community (via 16S rRNA sequencing) associated with the bulk and rhizosphere soil of sixteen strawberry cultivars in two controlled field studies, we explored the relationships between the soil microbiome and plant resistance to two soilborne fungal pathogens of strawberry (Verticillium dahliae and Macrophomina phaseolina). Overall, the plants had a distinctive rhizosphere microbiome relative to the bulk soil, with higher abundances of known beneficial bacteria …

Barriers To Success: Sheep And Goat Producers In The Service-Grazing Industry, Erin A. Campbell-Craven

Master's Theses

Service-grazing is a novel term for grazing done on land not owned or rented by a livestock producer or manager, for the purpose of land management, and for which the owner or land manager receiving grazing services pays compensation to the service provider. This research project seeks to gather detailed information about producers in the Western United States, providing grazing services under this project’s definition of “service-grazing”, with a focus on those operating in California, in order to discover the business models or practices necessary to be successful within a service-based grazing operation. To this end, an online survey consisting …

Quantitative And Qualitative Error Re-Analysis Of Tidal Datasets, Ernesto Andrew Ledezma

Master's Theses

Tidal data forms the basis for understanding and quantifying sea-level rise and tidal statistics. While quality assurance methods based upon spectral and harmonic analysis have been applied to individual tidal records, these methods have not been used to assess global tidal datasets. In this thesis, four west coast tidal records were examined using harmonic analysis methods to investigate uncertainty on a monthly averaged basis. Uncertainty was identified using a method that quantifies time lag as a linear regression of height difference between a predicted and measured tidal height and the predicted rate of change of tidal height. Errors identified through …

Cal Poly Pier Master Plan, Troy A. Lawson

Master's Theses

The Cal Poly Pier (Pier) Master/Facility Plan (FP) document provides the vision of the future for the Pier, a marine science research facility. The Plan facilitates project development and management of the Pier while meeting university and department research goals. Specifically, the FP document establishes goals and strategies to direct long-term development of the Pier, streamlines agency approval and permit requirements, provides context for pier management, and assists the permitting process for future development as it relates to regulatory permits and programmatic growth on the Cal Poly Pier to help meet goals of the Center for Coastal Marine Sciences (CCMS). …

Design Of A 5 Degree Of Freedom Kinematic Stage For The Dual Crystal Backlighter Imager Diagnostic, Nicholas Nguyen

Master's Theses

The National Ignition Facility (NIF) is home to the world’s most energetic laser. The facility is one of the leading centers in inertial confinement fusion (ICF) experiments to research and understand sustainable fusion energy. To fully document and understand the physics occurring during experiments, precise diagnostics are used for a wide range of purposes. One diagnostic, the crystal backlighter imager (CBI), allows for X-ray imaging of the target at late stages of its implosion.

The aim of this project was to increase the current capabilities of the CBI diagnostic with the addition of a second crystal. This thesis focuses on …

Mindfulness For Stress Reduction: Qualitative Analysis Of Perceptions From College Students And Mindfulness Instructors, Beth Marie Merlo

Master's Theses

Although mindfulness interventions with college students have yield positive results, many students are not continuing to engage after the interventions. This may be because very little research has been done to investigate the health behavior beliefs of college students in regard to mindfulness for stress reduction. The purpose of this investigation was to identify the most influential components of the Integrated Behavioral Model (IBM) that potentially assist with predicting college student participation in mindfulness activities for stress reduction. Interviews, informed by the IBM, were conducted with 20 current college students and 5 current mindfulness instructors working with college students. The …

Analysis Of Aquifer And Operational Conditions For Successful Soil Aquifer Treatment Of Treated Wastewater Via Synthesis Of Published Full-Scale And Laboratory-Scale Studies, Matthew I. Murray

Master's Theses

Soil aquifer treatment (SAT) of treated wastewater performance was evaluated across published full-scale and lab-scale studies developing insights on the aquifer and operational factors that affect SAT efficacy. The goal of this study was to develop a basis for predicting the contaminant removal capabilities of any given aquifer during managed recharge with treated wastewater.

Over 40 published SAT studies were reviewed and systematically compared to determine the influence of five major factors on contaminant removal performance: geologic composition, geochemical conditions, hydrogeological conditions, operational methods, and source water quality. Removal mechanisms for standard contaminants (dissolved and total organic carbon, nitrogen, and …

Analysis And Optimization Of Colorimetric Nanosensors For Rapid Detection Of Microbes In Water, Ruby A. Lang

Master's Theses

Access to safe water is a basic human right recognized by the United Nations General Assembly in 2010 (WHO, 2020). However, a least 2.2 billion people globally still are without safely managed water services meaning they use a drinking water source that can be contaminated with faeces (WHO, 2020). With such a pressing global health issue, it is clear that improvement to water systems is important and required in the Agenda 2030 Sustainable Development Goals (SDGs). However, to improve water systems and prove they are safe water sources, water quality testing must occur. A solution to this issue is the …

Altering An Epoxy-Amine Thermoset's Performance Through Varying Mix Ratios, Kiersten M. Smith

Master's Theses

Epoxy resins are used in a number of different industries and therefore have application-specific material requirements, from satellites that require materials that operate in space, to paints and coatings that require high scratch resistance and mechanical durability, to medical devices, designed to be in continuous contact with biological fluids. Commercial epoxy products come with manufacturer’s information explaining the epoxy properties and recommended preparation processing conditions, which may include epoxy resin to curing agent mix ratio (Part A : Part B), cure time, and cure temperature, for example. Due to proprietary reasons, it can be difficult to understand why these values …

Pier Portal, Alec W. Hardy

Master's Theses

The Pier Portal marine monitoring system is an internet controlled underwater camera that will enable students, researchers, and the general public the ability to monitor underwater marine life and ocean conditions. Installed at Cal Poly’s Center for Coastal Marine Science pier at Avila Beach, California, the camera can be commanded in real-time to raise or lower to any position between the top of the pier and the bottom of the ocean floor, while providing a live-stream video to the operator and general public. This thesis effort focused on the integration of the various subsystem components through software, and the development …

Planning For Pollinators, Encouraging Biodiversity For Agriculture Resiliency, Sebastian Brian Cardoza

Master's Theses

Pollinators are essential to food production globally. Without them, the production of food becomes increasingly difficult, time consuming, and costly. Unfortunately, due to the rapid changes to our earth's physical and climatic structure millions of species are becoming classified as threatened, endangered or extinct. Among these declining species are pollinating insects such as Aphis mellifera (honeybee) and other native species. This is due to a phenomenon known as colony collapse disorder (CCD) and other native bees. The decline indicates that the future habitability of earth may be in jeopardy. The solution to this crisis is to expand the habitat of …

Analysis And Design Of An Off-Grid Residential Power System, Christopher Rotsios

Master's Theses

This thesis aims to provide a recommended power system design for optimal efficiency, reliability, and cost in off-grid applications. The power system examined in this project is a residence in an off-grid community called Quail Springs that generates its energy from roof mounted solar panels. The existing system was analyzed to see what equipment can remain, what needs to be upsized, and what needs to be added to the system. Two power systems are considered for the residence: a fully AC power system and a hybrid AC/DC power system. Simulations were run in PSCAD to compare the efficiencies of the …

The Effect Of Orientation On The Ignition Of Solids, David Morrisset

Master's Theses

The ignition of a solid is an inherently complex phenomenon influenced by heat and mass transport mechanisms that are, even to this day, not understood in entirety. In order to use ignition data in meaningful engineering application, significant simplifications have been made to the theory of ignition. The most common way to classify ignition is the use of material specific parameters such as such as ignition temperature (T_ig) and the critical heat flux for ignition (CHF). These parameters are determined through standardized testing of solid materials – however, the results of these tests are generally used in applications …

Three Axis Attitude Control System Design And Analysis Tool Development For The Cal Poly Cubesat Laboratory, Liam T. Bruno

Master's Theses

The Cal Poly CubeSat Laboratory (CPCL) is currently facing unprecedented engineering challenges—both technically and programmatically—due to the increasing cost and complexity of CubeSat flight missions. In responding to recent RFPs, the CPCL has been forced to find commercially available solutions to entire mission critical spacecraft subsystems such as propulsion and attitude determination & control, because currently no in-house options exist for consideration. The commercially available solutions for these subsystems are often extremely expensive and sometimes provide excessively good performance with respect to mission requirements. Furthermore, use of entire commercial subsystems detracts from the hands-on learning objectives of the CPCL by …

Abalone Fishermen, Changing Management Practices, And The Creation Of A False Dichotomy, Tyler G. Hoyt

Master's Theses

This thesis traces the history of the abalone fisheries on the California Coast and how those fisheries have been understood and shaped by humans over time. An overarching interest that guides this effort is how indigenous populations used abalone and otters (as well as other marine resources) purposefully for millennia prior to European arrival. However, this work is not entirely focused on prehistory. Instead, it shows how a lack of understanding of this prehistory shaped the conservation efforts of the California Department of Fish and Game and its ultimate decision to close the commercial fishery in 1997. In this sense, …

Reduction Of Fat Content In Processed Meats Using Hot-Boning And Cold-Batter Mincing Technology, Morgan P. Wonderly

Master's Theses

Processed meats have received negative publicity due to high fat contents that have been linked to adverse effects on human health. Fat is an essential ingredient in many processed meat products, so reducing this all while maintaining the desired characteristics of the product is a challenge. The purpose of this study was to generate low-fat meat products using a combination of hot-boning/crust-freeze-air-chilling (HB-CFAC) and cold-batter mincing (CBM) technologies. Pork hams were subjected to HB-CFAC or chill-boning/crust-freeze-air-chilling (CB-CFAC) prior to 3 min pre-mincing and 6 min mincing for control gels with back-fat addition or low-fat gels with water addition instead of …

Wearable Heart Sound And Ekg Recorder, Grace R. Larson

Master's Theses

Acute congestive heart failure is a leading cause of morbidity and mortality. Patients often undergo repeated hospitalizations with an annual cost in excess of $32B dollars. Early detection of impending acute congestion allows for pharmaceutical interdiction that prevents hospitalization, improves outcomes, and reduces healthcare spending. A subcutaneous implantable monitoring device that detects impending acute congestive heart failure by using heart sounds may provide a valuable tool that can be used to titrate heart failure medications to prevent acute heart failure requiring hospitalization. The device may be used to measure changes in the intervals between the R-wave and S1 and S2 …

A Study Of The Utilization Of Panel Method For Low Aspect Ratio Wing Analysis, William Barton D. Newey

Master's Theses

This study demonstrates the applicability of using a modified application strategy of panel method to analyze low aspect ratio wings at preliminary design phases. Conventional panel methods fail to capture the leading edge vortex (LEV) that is shed by wings with low aspect ratios, typically below 2 depending on planform. This aerodynamic phenomenon contributes to a significant amount of the lift of these wings and the result is a drastic underestimation of the lift characteristics when analyzed by conventional panel method. To capture the effect of the leading edge vortex, a panel method code was used with an extended definition …

A Comparative Study On Seismic Analysis Methods And The Response Of Systems With Classical And Nonclassical Damping, Noah G. Bleichner

Master's Theses

This thesis investigated the application of seismic analysis methods and the response of idealized shear frames subjected to seismic loading. To complete this research, a Design Basis Earthquake (DBE) for a project site in San Luis Obispo, CA, and five past earthquake records were considered. The DBE was produced per the American Society of Civil Engineers’ Minimum Design Loads for Buildings and Other Structures (ASCE 7-10) and used for application of the Equivalent Lateral Force Procedure (ELFP) and Response Spectrum Analysis (RSA). When applying RSA, the modal peak responses were combined using the Absolute Sum (ABS), Square-Root-of-the-Sum-of-Squares (SRSS), and Complete …

Design Of A Martian Communication Constellation Of Cubesats, Scott J. Pirkle

Master's Theses

Spacecraft operating on the Martian surface have used relay satellites as a means of improving communication capabilities, mainly in terms of bandwidth and availability. However, the spacecraft used to achieve this have been large spacecraft (1000s of kilograms) and were not designed with relay capability as the design priority. This thesis explores the possibility of using a CubeSat-based constellation as a communications network for spacecraft operating on the Martian surface. Brute-force techniques are employed to explore the design space of possible constellations. An analysis of constellation configurations that provide complete, continuous coverage of the Martian surface is presented. The stability …

Flexible Fault Tolerance For The Robot Operating System, Sukhman S. Marok

Master's Theses

The introduction of autonomous vehicles has the potential to reduce the number of accidents and save countless lives. These benefits can only be realized if autonomous vehicles can prove to be safer than human drivers. There is a large amount of active research around developing robust algorithms for all parts of the autonomous vehicle stack including sensing, localization, mapping, perception, prediction, planning, and control. Additionally, some of these research projects have involved the use of the Robot Operating System (ROS). However, another key aspect of realizing an autonomous vehicle is a fault-tolerant design that can ensure the safe operation of …

Development And Characterization Of An Iot Network For Agricultural Imaging Applications, Jacob D. Wahl

Master's Theses

Smart agriculture is an increasingly popular field in which the technology of wireless sensor networks (WSN) has played a large role. Significant research has been done at Cal Poly and elsewhere to develop a computer vision (CV) and machine learning (ML) pipeline to monitor crops and accurately predict crop yield numbers. By autonomously providing farmers with this data, both time and money are saved. During the past development of a prediction pipeline, the primary focuses were CV and ML processing while a lack of attention was given to the collection of quality image data. This lack of focus in previous …