Engineering Commons^™

Improvement Of Rotation Capacity Of Composite Beam-To-Hss Column Connections Using External Horizontal Stiffeners, Mahdi Afshar Arjmand

Master's Theses

Improvement of Rotation Capacity of Composite Beam-to-HSS Column Connections Using External Horizontal Stiffeners

Mahdi Afshar Arjmand

This thesis focuses on the analysis of out-of-plane deformation (OOP) in column flange located in the panel zone of composite beam-to-column steel connection, as a critical aspect of steel structural engineering. This type of connection is an integral component of steel structures, and understanding their behavior is essential for ensuring safety and performance. The investigation involves examining the causes, factors influencing, and potential mitigation strategies for out-of-plane deformation of HSS flange column in these connections. Beam-to-column connections play a vital role in transferring loads …

A Numerical Modeling Analysis Of The San Francisco Bay And Sacramento-San Joaquin Delta: Riverine, Tidal, And Wind Processes, Drake A. Abrahamsson

Master's Theses

The primary motivation of this study is to analyze the 1D-2DH hydrodynamic model of the San Francisco Bay and Sacramento-San Joaquin Delta (SFBD) outlined in Nederhoff et al. (2021). I compared model water level data to 70 tidal records from the National Oceanic and Atmospheric Association (NOAA), the United States Geological Survey (USGS), the California Data Exchange Center (CDEC), and from local municipalities throughout the Bay Area to investigate how the model captures water levels and tidal constituent amplitudes. While the Nederhoff et al (2017) model analyzed an extended time period from 1950-2019, I analyzed M2 amplitude and tidal water …

The Tidal Prism, Viable Eelgrass Habitat, And The Effects Of Sea Level Rise In Morro Bay, Kaden A. Caliendo

Master's Theses

The tidal prism, or the volume of water exchanged from the sea to an estuary from mean low to mean high tide, influences system hydrodynamics and ecological functioning. Since 1884, the tidal prism in Morro Bay, California has been estimated to be decreasing over time due to sedimentation from upstream practices. What is the current tidal prism in Morro Bay and how will that change with sea level rise? How will eelgrass respond to rising sea levels?

For this study, inexpensive tidal gauges were deployed at four locations in Morro Bay from March to August 2023 to measure spatially varying …

Experimental Characterization And Computer Vision-Assisted Detection Of Pitting Corrosion On Stainless Steel Structural Members, Riley J. Muehler

Master's Theses

Pitting corrosion is a prevalent form of corrosive damage that can weaken, damage, and initiate failure in corrosion-resistant metallic materials. For instance, 304 stainless steel is commonly utilized in various structures (e.g., miter gates, heat exchangers, and storage tanks), but is prone to failure through pitting corrosion and stress corrosion cracking under mechanical loading, regardless of its high corrosion resistance. In this study, to better understand the pitting corrosion damage development, controlled corrosion experiments were conducted to generate pits on 304 stainless steel specimens with and without mechanical loading. The pit development over time was characterized using a high-resolution laser …

Estimating The Impact Of Infill Housing On Reduction In Vehicle Miles Traveled, Peyton Marie Ratto

Master's Theses

Vehicle miles traveled (VMT) and its relationship with the built environment has been extensively studied. Most notably, five D variables of the built environment including density, diversity, design, destination accessibility, and distance to transit are the key variables included in this research to explain VMT generation from housing developments. This thesis uses prior research that developed robust statistical models and findings to create a framework to estimate VMT reduction affected by infill housing developed using incentives provided by the state compared to a regional comparator. The regional comparator is typically a suburban single-family housing development in the region. The models …

Biodegradation Of Methyl Tert-Butyl Ether And Tert-Butyl Alcohol Using Bioaugmentation With Biowish® Aqua, Elizabeth Villanueva

Master's Theses

Aqua, a commercial product manufactured by BiOWiSH® Technologies, was utilized in this research to study its effectiveness to biodegrade methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA). Microcosms containing varying concentrations of MTBE and TBA as well as a growth media and mineral salt solution were examined. Analytical instrumentation used in this study included the use of a gas chromatograph-mass spectrometer (GC/MS) to determine concentrations of MTBE and TBA and a spectrophotometer to extrapolate approximate active biomass concentrations in each experiment. Four different environmental conditions were tested for both MTBE and TBA. The environmental conditions tested for each contaminant included: …

Investigation Of Temperature, Solution Strength, And Applied Stress Effects On Cation Exchange Processes In Geosynthetic Clay Liners, Kurt Katzenberger

Master's Theses

A laboratory test program was conducted to investigate the effects of temperature, solution strength, and applied stress over increasing conditioning durations on cation exchange processes in sodium bentonite (Na-B) geosynthetic clay liners (GCLs). The test program was intended to determine if the variables of temperature, solution strength, and applied stress had beneficial or detrimental effects on the engineering behavior of Na-B GCLs in municipal solid waste (MSW) landfills and laboratory testing applications. Needlepunched-reinforced, double non-woven Na-B GCL specimens were conditioned in fluids of increasing ionic strength (DI water, 2 mM CaCl2, 50 mM CaCl2, and 200 mM CaCl2 representing control, …

Fabrication Of Thin-Film Composite, Reverse-Osmosis Membranes With Polyethylenimine Modifications For Enhancing Membrane Fouling Resistance, Stephanie N. Hamilton

Master's Theses

Increasing water reuse opportunities for communities has become increasingly important as access to clean water is becoming more scarce. Reverse Osmosis (RO) is an advanced treatment technology used in water recycling wastewater for potable reuse applications. RO is a promising technology; however, the membranes have limitations including their high energy demand and their susceptibility to membrane fouling. The main objective of this study was to develop a reproducible method for the fabrication of RO membranes with enhanced flux and reduced susceptibility to fouling. Literature contains numerous publications on fabrication of thin film composite (TFC) RO membranes with high performance. However, …

Analysis Of Current And Future Flood Hazard In The Sacramento-San Joaquin Delta, Nicholas L. Mcguire

Master's Theses

The primary motivation of this study is to estimate the current and future flood hazard throughout the Sacramento-San Joaquin Delta in the context of sea-level rise. I also analyzed the effects of storm surge and river flow on extreme events to better understand how these events originate and vary spatially and in time. To address this goal, I combined digital water level records (primarily 1983-present) with archival data collected by the California Department of Water Resources (1929-1983) to reevaluate flood hazard in the Delta and investigate the possible sensitivity of the region different sea-level rise projections. Available archival records from …

Effects Of Experimental Scale On The Adsorption Of Two Pharmaceutical Drugs Detected In Municipal Wastewater Effluent, Michael Moore

Master's Theses

Pharmaceutical drugs are being produced and consumed in increasing quantities every year and are poorly treated by conventional wastewater treatment processes, leading to increasing detection of such compounds in surface water, groundwater, and municipal drinking water. Soil aquifer treatment (SAT) is a promising method for treating these emerging compounds through combined adsorption and degradation of target compounds in soil. This thesis examines the consistency of results from typical studies like adsorption isotherms and soil columns utilized in analysis of SAT performance, across varying experimental scales. The adsorption behavior of two pharmaceuticals was investigated as a function of experimental scale and …

Measuring Accessibility For Pedestrians, Bicyclists, And Transit Riders To Grocery Stores In The Excelsior/Outer Mission Neighborhoods Of San Francisco, Alexandra Lee-Gardner

Master's Theses

Grocery stores are an important amenity in neighborhoods and access to grocery stores is important for health and well-being. While grocery store accessibility is a popular topic of research, studies measuring access for pedestrians, bicyclists, and transit riders are extremely rare. When a new store opened in the Excelsior/Outer Mission districts of San Francisco on a street lacking basic infrastructure for pedestrians, bicyclists, and transit riders, the importance of this study became apparent. The Excelsior/Outer Mission neighborhood has a shocking number of collisions (over 1,100 between 2015 and 2019), elevated levels of walking, biking, and transit ridership, and minimal safe …

Design, Fabrication, And Testing Of Mechanical Hinges With Snap-Fit Locking Mechanisms In Rigid Origami Structures, Colby James Scanlon

Master's Theses

The ancient art of ‘origami’ has recently become the source of inspiration for engineers to create structures that can unfold from a compact state to a fully deployed one. For instance, researchers have currently adopted origami designs in various engineering disciplines, including aerospace engineering, robotics, biomedical engineering, and architecture. In particular, architects have been interested in designing origami-inspired rigid walled structures that can be deployed as disaster-relief shelters. This type of design has three main advantages: transportability, constructability, and rigidity. Although there has been increased interests in deployable structures, limited research has been conducted on evaluating their structural performance, specifically …

Construction Industry Hesitation In Accepting Wearable Sensing Devices To Enhance Worker, Harrison M. Fugate

Master's Theses

The construction industry is one of the most unsafe industries for workers in the United States. Advancements in wearable technology have been proven to create a safer construction environment. Despite the availability of these devices, use within the construction industry remains low. The objective of this research is to identify and analyze the causes behind the reluctance of the construction industry to implement two specific wearable safety devices, a biometric sensor, and a location tracking system. Device acceptance was analyzed from the perspective of the user (construction field labor) and company decision makers (construction managers). A modified unified theory of …

Evaluation Of Cost-Effective Alternative Designs For Rural Expressway Intersections, Jonathan Howard

Master's Theses

Despite numerous studies demonstrating the effectiveness of Restricted Crossing U-Turn (RCUT) intersection design, its implementation remains uneven and close to zero in some large states such as California. This research provides a comprehensive framework to estimate the operational and safety performance of future RCUT designs in California. The framework is demonstrated for five intersections located on high-speed rural expressways in California using VISSIM microsimulation models to measure operational performance for each intersection including the base condition with the existing Two-Way Stop-Controlled (TWSC) intersection and two RCUT designs. To evaluate future safety performance, the microsimulation models were further utilized to compile …

Assessing The Impact Of Bicycle Infrastructure And Modal Shift On Traffic Operations And Safety Using Microsimulation, Katherine E. Lee

Master's Theses

A transportation system designed to prioritize the mobility of automobiles cannot accommodate the growing number of road users. The Complete Streets policy plays a crucial part in transforming streets to accommodate multiple modes of transportation, especially active modes like biking and walking. Complete streets are referred to as streets designed for everyone and enable safety and mobility to all users. A strategy of complete streets transformation is to connect isolated complete street segments to form a complete network that improves active mobility and public transit ridership.

This research assessed the impact of efficiently and equitably connecting and expanding the biking …

Potential Impact Of Contour Bunds On Diclofenac Removal For Stormwater Control In Rangeland Applications, Braden Alan Whitehead

Master's Theses

Diclofenac (DCF) and other emerging contaminants have been found in environments worldwide. These contaminants may enter the environment due to the application of treated wastewater, biosolids and direct excrement related to veterinary application. Leakage from the soils toward the groundwater is largely controlled by sorption and microbial degradation. Most studies on the environmental fate of DCF have focused on degradation during wastewater treatment processes. However, little is known about their behavior in soil. In this study, the combined effect of adsorption and degradation of diclofenac has been investigated in four (4) 24 ft³ agricultural soil-filled beds designed to mimic …

Comparison Of Two Advanced Oxidation Processes For Their Production Of Hydroxyl Radicals And Evaluation Of A Uv/Ozone Aop At Varying Uv Fluence For Treating Diclofenac, Alexandra Cass

Master's Theses

This study explores the efficacy of two advanced oxidation processes for generation of hydroxyl radicals to promote degradation of emerging contaminants. Drought and water shortage have become pressing issues caused by our world’s changing climate. Water reclamation and reuse are increasingly important options for relieving this water stress. Water reuse runs the risk of reintroducing recalcitrant compounds that can accumulate in our bodies and environment. Advanced treatment methods that degrade these compounds are vital to protect our health and the health of the environment while providing necessary water resources. Advanced oxidation processes (AOPs) have shown great promise for removing recalcitrant …

Modeling The Groundwater Basin In The Northern Cities Management Area, Allyson Swain

Master's Theses

A model was developed to simulate the groundwater of 8,300 acres of the Northern Cities Management Area (NCMA), which encompasses the northern portion of the Arroyo Grande Watershed and a small subset of the Santa Maria Valley Groundwater Basin. This watershed and groundwater basin is located on the coast and contains Oceano and the Cities of Arroyo Grande, Grover Beach, Pismo Beach. Groundwater in the NCMA is used heavily for agricultural irrigation in the southern portion and municipal applications in the northern portion. Up to 18 of these municipal wells and over 50 irrigation wells are drawing groundwater at any …

Groundwater Model Studying Effects Of Existing Recharge Basin And Proposed Subsurface Barrier For A Ranch In Santa Rosa Creek Watershed, Stefan J. Young

Master's Theses

A groundwater model of a 126.2-acre ranch in Cambria, California was expanded upon to analyze the effects of artificial recharge and a subsurface barrier. The ranch lies within the 48mi² Santa Rosa Creek Watershed along the Central Coast of California. The mainly agricultural watershed outfalls to the Pacific Ocean to its west. Creek Lands Conservation, a non-profit that aims to conserve and restore habitat along the Central Coast, plans to identify projects to restore stream flow during dry seasons in the creek that runs through the Santa Rosa Creek Watershed and to increase artificial groundwater recharge. This study focuses …

Analysis And Optimization Of A Colorimetric Nanosensor For Rapid Detection Of Escherichia Coli In Water, Sarah M. Stabler

Master's Theses

Safe drinking water is essential for life, yet at least two billion people around the world consume water contaminated with pathogens among other pollutants. Standard methods like polymerase chain reaction (PCR) and membrane filtration have been developed to detect enteric pathogens in water. However, these methods are limited in their accessibility due to long wait times to obtain results, and the requirements of skilled expertise, electricity, and laboratory equipment. This research has focused on addressing some of these limitations by analyzing the mechanisms of work and optimizing an indirect colorimetric nanosensor developed in previous research. The colorimetric nanosensor investigated herein …

Study Of Fragility Functions For Assessing Damage To Water Pipe Networks Caused By Earthquake Loading, Dylan Joseph Merlo

Master's Theses

The performance of water lifelines during seismic events is an area of ongoing research. In this study we evaluate eight (8) different seismic events and the impact that ground shaking and ground deformations had on water pipeline systems. The overall goal of this work is to provide municipalities and utility providers with tools for mitigating the consequences of seismic hazards on water lifeline systems by analyzing the accuracy of damage estimation models. Three (3) different repair rate models are evaluated using data collected from the seismic events and compared to observed repair rate data. Results are analyzed to examine the …

Adaptive Laboratory Evolution Of Scenedesmus Obliquus For Increased Carbohydrate Content And Biomass Productivity, Nahel Ali

Master's Theses

The economics of microalgal bioproduct commercialization would benefit from increased accumulation of energy storage compounds, such as carbohydrates and lipids, and increased biomass productivity. This thesis explores two adaptive laboratory evolution strategies for improving Scenedesmus obliquus: single UV-mutagenesis and low light cultivation at a high dilution rate to produce cultigens with greater carbohydrate content and iterative UV-mutagenesis and selection under outdoor conditions in a raceway pond at a high dilution rate to increase biomass productivity.

Two cultigens were generated with the goal of increased carbohydrate content: K5 and K7. Both were mutagenized for 5 seconds and cultivated in 50-mL …

Incorporating Shear Resistance Into Debris Flow Triggering Model Statistics, Noah J. Lyman

Master's Theses

Several regions of the Western United States utilize statistical binary classification models to predict and manage debris flow initiation probability after wildfires. As the occurrence of wildfires and large intensity rainfall events increase, so has the frequency in which development occurs in the steep and mountainous terrain where these events arise. This resulting intersection brings with it an increasing need to derive improved results from existing models, or develop new models, to reduce the economic and human impacts that debris flows may bring. Any development or change to these models could also theoretically increase the ease of collection, processing, and …

Impact Of Soil Properties On Removal Of Emerging Contaminants From Wastewater Effluent During Soil Aquifer Treatment, Lauren N. Riley

Master's Theses

This study evaluates soil properties that impact the effectiveness of soil aquifer treatment (SAT) as a polishing step to the remove two classes of ECs from wastewater effluent: pharmaceuticals and personal care products (PPCPs), and engineering nanomaterials (ENMs). In recent years, it has been determined that elevated levels of emerging contaminants (ECs) are being released into the environment with wastewater effluent. ECs are proven to cause adverse environmental and health effects as a result of long-term exposure. It is important to evaluate sustainable solutions to improve the current methods of wastewater treatment to address these ECs.

Soil aquifer treatment (SAT) …

Implementation Of An Open-Source Digital Image Correlation Software For Structural Testing, Nicole V. Buck

Master's Theses

This thesis investigates the appropriateness of a simplified, open-source digital image correlation (DIC) software for use in quasi-static, structural testing utilizing two-dimensional (2D) DIC measurements. DIC is a non-contact optical measurement technique that uses computer vision to track unique attributes on the surface of an object. For structural testing, traditional instrumentation such as displacement sensors and strain gages are impractical for full field measurements due their limited ability to capture large amounts of data. However, over the past decade, DIC has proven a successful method for full-field kinematics measurements, making it an appealing tool for collecting high densities of accurate …

Dairy Manure Flushwater Treatment By Algae Raceway Ponds And Aerated Biofilm Reactors, Darin Son

Master's Theses

Nitrogen removal technologies can help dairy industries meet their nutrient management needs. This thesis investigated two separate treatment technologies for total ammonia nitrogen (TAN) removal: algae raceway ponds and aerated biofilm reactors. Six 1000- liter algae raceway ponds and four 1000-liter tote tanks, each equipped with 10 sheets of nonwoven geotextile (i.e., thermally bonded or needle-punched) biofilm substrate, were used to treat the effluent from a flush dairy in central coastal California (TAN = 251 mg/L, cBOD5 = 204 mg/L). For the algae raceway ponds (TAN loading rate = 7 - 35 g/m³-day among 7-, 10- and 14-day hydraulic residence …

Development Of Zeolitic Imidazolate Frameworks For Enhancing Post-Combustion Co2 Capture, Dustin Lee

Master's Theses

Post-combustion CO₂ capture is a promising approach for complementing other strategies to mitigate climate change. Liquid absorption is currently used to capture CO₂ from post-combustion flue gases. However, the high energy cost required to regenerate the liquid absorbents is a major drawback for this process. As a result, solid sorbents have been investigated extensively in recent years as alternative media to capture CO₂ from flue gases. For example, metal organic frameworks (MOFs) are nanoporous materials that have high surface areas, large pore volumes, and flexible designs. A large number of MOFs, however, suffer from 1) low CO …

Analyzing The Safety Effects Of Edge Lane Roads For All Road Users, Marcial F. Lamera

Master's Theses

This thesis acts as one of the first studies that analyzes the safety effects of Edge Lane Roads (ELR) for all road users. This is important since ELRs can be a solution to many issues, such as alleviating congestion, increasing multimodality along roadways, and reducing maintenance costs. ELRs in both North America and Australia were observed. Starting with the North American ELRs, the following study designs were employed to estimate the safety of ELRs: (a) yoked comparison where each ELR installation was matched with at least two comparable 2-lane roads to serve as comparison sites and (b) an Empirical Bayes …

Design Of Structural Stand For High-Precision Optics Microscopy, Sara T. Novell

Master's Theses

Lawrence Livermore National Lab (LLNL) is home to the National Ignition Facility (NIF), the world’s largest and most energetic laser. Each of the 192 beamlines contains dozens of large optics, which require offline damage inspection using large, raster-scanning microscopes. The primary microscope used to measure and characterize the optical damage sites has a precision level of 1 µm. Mounted in a class 100 clean room with a raised tile floor, the microscope is supported by a steel stand that structurally connects the microscope to the concrete ground. Due to ambient vibrations experienced in the system, the microscope is only able …

Optimization And Longevity Of Functionalized Multi-Walled Carbon Nanotube-Enabled Membranes For Water Treatment, Madeleine Michael Isabella White

Master's Theses

Water scarcity is a growing concern at the global scale. Large scale water reuse is growing both in necessity and popularity. Before water reuse can be performed efficiently on a large scale or be used for potable supply, even indirectly, contaminants of emerging concern (CECs) will need to be treated at the full scale. Advanced oxidation processes (AOPs) are a form of advanced water treatment capable of treating a wide range of CECs. This study contributes to the growing field of AOPs and more specifically AOPs using ozone combined with functionalized multi-walled carbon nanotubes (MWCNTs). Ozonation of MWCNTs has been …