Engineering Commons^™

Development Of Mirror Flexures For Use In The Muvi Instrument, Colin W. Harrop

Master's Theses

The Miniaturized Ultraviolet Imager (MUVI), is a compact wide field UV imaging instrument in development at UC Berkeley Space Sciences Laboratory and Cal Poly, San Luis Obispo. MUVI is designed to fit in a 2U CubeSat form factor and provide wide field, high resolution images of the ionosphere at far ultraviolet wavelengths. This thesis details the design and analyses of MUVI’s deployable cover mirror mounting flexures. Three different flexure geometries were evaluated, an optimal candidate was determined based on a number of criteria including isolation of vibration and stress to the mirrors, manufacturability and cost. The design of the flexure …

Human Microbiome Transfer In The Built Environment Differs Based On Occupants, Objects, And Buildings, Andrew J. Hoisington, Christopher E. Stamper, Katherine L. Bates, Maggie A. Stanislawski, Michael C. Flux, Teodor T. Postolache, Christopher A. Lowry, Lisa A. Brenner

Faculty Publications

Compared to microbiomes on other skin sites, the bacterial microbiome of the human hand has been found to have greater variability across time. To increase understanding regarding the longitudinal transfer of the hand microbiome to objects in the built environment, and vice versa, 22 participants provided skin microbiome samples from their dominant hands, as well as from frequently and infrequently touched objects in their office environments. Additional longitudinal samples from home environments were obtained from a subset of 11 participants. We observed stability of the microbiomes of both the hand and built environments within the office and home settings; however, …

Leveraging Automated Fiber Placement Computer Aided Process Planning Framework For Defect Validation And Dynamic Layup Strategies, Joshua Allen Halbritter

Theses and Dissertations

Process planning represents an essential stage of the Automated Fiber Placement (AFP) workflow. It develops useful and efficient machine processes based upon the working material, composite design, and manufacturing resources. The current state of process planning requires a high degree of interaction from the process planner and could greatly benefit from increased automation. Therefore, a list of key steps and functions are created to identify the more difficult and time-consuming phases of process planning. Additionally, a set of metrics must exist by which to evaluate the effectiveness of the manufactured laminate from the machine code created during the Process Planning …

Investigating The Detriment Of Development Assistance: A Geopolitical Analysis Of Sino-Djibouti Relations Through The Lens Of China’S Belt And Road Initiative, Elizabeth Elenwo-Roger

Independent Study Project (ISP) Collection

This research paper will evaluate Africa’s past with debt accumulation, focusing on the role of the Washington Consensus spearheaded by the Bretton Woods Institutions in its failed attempts to relieve the continent’s debt distresses and further aggravate Africa’s already fractured relationship with the West. It will highlight the goals of the Belt and Road Initiative, assessing China’s South-South cooperation approach to its relations with Djibouti and the Horn of Africa. Specifically, it will investigate claims of China engaging in debt-trap diplomacy and the extent to which this term infringes upon the agency of African leaders. The general research question investigates …

Entre Punzones Y Percutores Reconstrucción De Tecnología Ósea De Los Selk'nam (Tierra Del Fuego), Rachel Dietz

Independent Study Project (ISP) Collection

Esta investigación se enfoca en el estudio, reconstrucción y uso de la tecnología ósea empleada por las sociedades cazadoras-recolectoras-pedestres que ocuparon el litoral Atlántico de Tierra del Fuego, durante el Holoceno, específicamente se enfoca en la tecnología utilizada por los Selk´nam del Norte de Tierra del Fuego. La tecnología ósea fue una parte importante de su cultura y dos tipos fueron elegidos para investigar: percutores blandos y punzones huecos. Los percutores blandos fueron confeccionados sobre huesos de guanaco, un recurso importante para las sociedades cazadoras-recolectoras.

Los percutores blandos fueron usados para la formatización de artefactos líticos a través de la …

Feasibility Analysis Of A Wave Powered Autonomous Underwater Vehicle, Yingchen Yang, Erick Martinez

Mechanical Engineering Faculty Publications

An autonomous underwater vehicle (AUV) powered by renewable energy would enable it to extend endurance and forward presence with no logistics tail for fuel. A wave powered concept AUV is proposed and analyzed for this purpose. The AUV is in a torpedo shape and employs a fully hull-encapsulated mass-spring-damper system as its power take-off (PTO) unit. While in the recharging mode, the AUV surfaces and converts wave energy for electricity. Considering the AUV of a common size, our analysis indicates that resonance of the AUV and/or its PTO, to be excited by ocean waves, becomes impossible in typical ocean conditions. …

Trust Model System For The Energy Grid Of Things Network Communications, Narmada Sonali Fernando, Zhongkai Zheng, John M. Acken, Robert B. Bass

Electrical and Computer Engineering Faculty Publications and Presentations

Network communication is crucial in the Energy Grid of Things (EGoT). Without a network connection, the energy grid becomes just a power grid where the energy resources are available to the customer uni-directionally. A mechanism to analyze and optimize the energy usage of the grid can only happen through a medium, a communications network, that enables information exchange between the grid participants and the service provider. Security implementers of EGoT network communication take extraordinary measures to ensure the safety of the energy grid, a critical infrastructure, as well as the safety and privacy of the grid participants. With the dynamic …

Gluten Free Diet Ameliorates Si Enteropathy In Iga Deficient Mice, Ryan Albert William Ball

Theses and Dissertations

Secretory IgA is the most abundant antibody in the intestinal mucosal and functions as the first line of defense against pathogens and micro-organisms in the gut. Selective IgA deficiency is the most common form of antibody deficiency. Clinically, IgA deficient patients are largely asymptomatic, they are however at a higher risk of developing certain inflammatory conditions like Celiac disease; an SI-specific enteropathy triggered by exposure to dietary gluten. Interestingly, celiac patients are 10-15 times more likely to have an IgA deficiency. Recent studies have shown that IgA^-/- mice develop enteropathy specifically in the ileum. We confirmed this phenotype in …

The Impact Of Using Tanks For The Equalization Step On The Performance Of A Psa Process, Behnam Fakhari Kisomi

Theses and Dissertations

The pressure equalization step between two adsorption beds is a key cycle step in many pressure swing adsorption (PSA) processes. It involves connecting two beds together, or two beds and a tank as a medium. The utilization of tanks for equalization in a bed-to-tank-to-bed (BTB) configuration could be advantageous to reduce the number of beds in PSA cycle. In this study, a binary gas mixture A and B, with A more strongly adsorbed than B, was used for the investigation of Stafstrom-type PSA cycles with bed-to-bed (BB) and bed-to-tank-to-bed (BTB) equalization steps using linear isotherm and isothermal equilibrium theory. For …

Role Of Sediment Type, Concentration, And Salinity On Clay Flocs, Ryan Michael Johnson

Theses and Dissertations

Experiments were performed to study floc formation in water bodies. In particular, the study aimed to systematically identify effects of water depth, time, salinity, initial clay concentration, and clay type on floc formation and settling. Three sediment types were chosen for this research are Three sediment types were chosen for this research: silica powder, with particle sizes comparable to clay flocs, kaolin clay and bentonite clay. Silica was chosen as a control because it did not form flocs. Kaolin represented low activity clay; bentonite was chosen as the high activity clay. Experiments lasted up to 48 hours. Graduated cylinders were …

Timing Deterministic Structural Model Updating Considering Impact And Fatigue Damage, Jason Michael Smith Jr.

Theses and Dissertations

Naval ship structures such as support trusses, hull sections, driving machinery, and load-bearing beams are subjected to various damage states that develop on short-term (i.e. impact) and long-term (i.e. fatigue) timescales. Naval structures fitted with a structural health monitoring system with damage detection abilities will enable appropriate real-time adjustments to the ships’ posture and control policies and thus have increased survivability and lethality. A digital twin can provide real-time condition assessment of naval structures when conjoined with a decision-making framework will increase naval ship survivability through informed response management. A fundamental challenge for the development of digital twins is reliable …

Vision Controlled Autonomous Stakebot For Driving Stakes And Its Digital-Twin, Corey Lee Leydig

Theses and Dissertations

In this thesis a novel vision-based AI driven autonomous ‘StakeBot’ is proposed to serve the agricultural 4.0 industries of the future. In recent years supply, demand and production of vegetables that are harvested from plants with weak stems like bell pepper, tomato, eggplant has been significantly up by several fold. With growing demand and new green-house establishments across the country production of vegetables will require a tremendous number of labors which will be hard to supply soon. To overcome the issues in addition to the labor shortages, automation through robotics will be the only viable solution. Plants like bell peppers …

An Autonomous Aerial Drone System For Water Fluorescence Mapping And Targeted Sampling, Kazi Ragib Ishraq Sanim

Theses and Dissertations

At present, aerial drones, also known as Uncrewed Aircraft Systems (UAS) or Unmanned Aerial Vehicles (UAV), are increasingly used in time and effort-heavy scientific exploration applications. One such application is inspecting the physical, chemical, and biological state of water bodies. This thesis presents a novel autonomous system capable of sensing water properties and collecting up to three 250 mL water samples from multiple sampling locations. The system features a customized aerial drone with an in-house built fluorescence sensor and pumping mechanism. It can also map the gradient of fluorescent content across the body of water to determine the best sampling …

Nondestructive Damage Detection And Stress Corrosion Crack Mitigation In Stainless Steel Plates, Andrew Philip Campbell

Theses and Dissertations

The ability to inspect and detect damage within a structure without permanent damage has broad appeal in a range of engineering applications from aerospace structures to nuclear facilities. Non-destructive evaluation (NDE) using guided ultrasonic Lamb waves has growing potential and popularity in these fields. Lamb waves are known for being sensitive to material properties and various defects across the thickness such as cracks in metallic structures and delamination or debonding in composite structures. Research has also been done on the development of fully non-contact system that generates and detects Lamb waves, particularly focused on the use of pulsed laser for …

Actuation And Sensing Applications Of Piezoelectric Transducers, Connor Griffin

Theses and Dissertations

Piezoelectric materials, defined by their ability to display a charge across their surface in response to mechanical strain, are great for use in actuation and sensing applications. Actuation applications include acoustic devices, motors and vibration damping while sensing applications include pressure sensors, medical devices, energy harvesting and structural health monitoring (SHM). The use of piezoelectric actuation and sensing across the lifecycle of aerospace metals is currently an expanding field with use cases beginning with the manufacturing process and ending with SHM.

The research presented in this thesis had three goals: (i) to develop methods for implementation of piezoelectric actuation in …

New Perspectives And Insights Into Direct Epoxidation Of C3H6 Using O2 And Ag Based Catalysts And Measurement Of Active Ag Site Concentration Of Promoted Ag Catalyst For C2H4 Epoxidation By H2 Pulse Titration Over Oxygen Pre-Covered Surface, Md Masudur Rahman

Theses and Dissertations

Direct epoxidation of C₃H₆ using molecular O₂ and Ag catalysts to produce propylene oxide (PO) selectively is a long-sought goal in the field of heterogeneous catalysis. In the early 1990’s Scientists at ARCO reported promising results of 58 – 59% selectivity to PO at 3.2% conversion of C₃H₆ over an unusual composition of 54.0 wt% Ag, 2.0 wt% K⁺, 0.5 wt% Mo and balance CaCO₃. Feed additives of ethyl chloride (EtCl), nitric oxide (NO) and CO₂ were stated necessary to achieve the claimed high PO selectivities. The roles …

Load Rating Evaluation Of Deteriorated Prestressed Channel Girders, Alexander Zane Henderson

Theses and Dissertations

The South Carolina Department of Transportation (SCDOT) is conducting a multi-year effort to load rate its inventory of over 9,400 bridges. This includes many bridges that are load posted due to potential structural considerations (e.g., outdated design loads, members whose capacity is difficult to assess, structural degradation). The number of load-posted bridges in South Carolina is expected to increase significantly due to recent efforts from SCDOT to assess the current state of bridge infrastructure. It is expected that the increased scrutiny may result in more load postings, which in turn may lead to restrictions on truck routes, potential bridge closures, …

Implementation Of The Downlink Communication System Of The Lmu Cubesat, Mohammed Alrabeeah

LMU Theses and Dissertations

In this thesis, we present the design and implementation of a CubeSat receiver system using the Universal Software Radio Peripheral (USRP) and GNU Radio. The goal of this project is to develop a low-cost and flexible ground station capable of receiving telemetry and payload data from CubeSats in real time. The CubeSat receiver operates in the UHF frequency range with a center frequency of 435 MHz and uses a software-defined radio (SDR) approach to provide wideband signal processing and demodulation capabilities. The satellite transceiver transmits an Ax.25 Transciever packet every 1 second using the Pumpkin CubeSat kit programmed in MPLab. …

A Device For Measuring Acoustic Output Intensity Of Transcranial Doppler Ultrasound Transducers For Comparison With Fda Regulations, Sarah Altman, Gregory Bashford, Benjamin Hage

Honors Program: Senior Projects (Public)

Transcranial Doppler Ultrasonography (TCD) is a non-invasive methodology which can evaluate cerebral blood flow velocity in real time. Single-element focused circular transducers placed on the scalp produce ultrasound waves capable of penetrating the skull with minimal aberration, enabling measurement of the Doppler shift. As such, TCD can measure blood flow velocity in the internal carotid and vertebral arteries, as well as the arteries of the Circle of Willis: the Anterior Cerebral (ACA), Posterior Cerebral (PCA), and Middle Cerebral Arteries (MCA). Intracranial aneurysm and ischemic stroke are serious conditions in which ballooning or occlusion of cerebral vessels cause insufficient perfusion, leading …

An Investigation Into The Economic Useful Life Of Commercial Aircraft As Impacted By Maintenance And Economic Variables, Robert Gallagher

Doctoral Dissertations and Master's Theses

This research involved examining the economic useful life of commercial aircraft and the impact of maintenance and economic variables on the viability and longevity of the asset. The data sample consisted of the entire population of Boeing commercial aircraft produced between 1956 and 2021. The objective was to determine the effect of both maintenance and economic variables on the longevity and usefulness of commercial aircraft. As manufacturers work with issues such as service life, economic life, safety, and critical design features, those in the aviation community focus on the operational side of the equation––how long can one operate the asset, …

Prediction & Active Control Of Multi-Rotor Noise, Samuel O. Afari

Doctoral Dissertations and Master's Theses

Significant developments have been made in designing and implementation of Advanced Air Mobility Vehicles (AAMV). However, wider applications in urban areas require addressing several challenges, such as safety and quietness. These vehicles differ from conventional helicopter in that they operate at a relatively lower Reynolds number. More chiefly, they operate with multiples of rotors, which may pose some issues aerodynamically, as well as acoustically. The aim of this research is to first investigate the various noise sources in multi-rotor systems. High-fidelity simulations of two in-line counter-rotating propellers in hover, and in forward flight conditions are performed. Near field flow and …

Autonomous Space Surveillance For Arbitrary Domains, David Zuehlke

Doctoral Dissertations and Master's Theses

Space is becoming increasingly congested every day and the task of accurately tracking satellites is paramount for the continued safe operation of both manned and unmanned space missions. In addition to new spacecraft launches, satellite break-up events and collisions generate large amounts of orbital debris dramatically increasing the number of orbiting objects with each such event. In order to prevent collisions and protect both life and property in orbit, accurate knowledge of the position of orbiting objects is necessary. Space Domain Awareness (SDA) used interchangeably with Space Situational Awareness (SSA), are the names given to the daunting task of tracking …

Real-Time Facial Expression Recognition Using Edge Ai Accelerators, Mark Heath Smith

Theses and Dissertations

Facial expression recognition is a popular and challenging area of research in machine learning applications. Facial expressions are critical to human communication and allow us to convey complex thoughts and emotions beyond spoken language. The complexity of facial expressions creates a difficult problem for computer vision systems, especially edge computing systems. Current Deep Learning (DL) methods rely on large-scale Convolutional Neural Networks (CNN) which require millions of floating point operations (FLOPS) to accomplish similar image classification tasks. However, on edge and IoT devices, large-scale convolutional models can cause problems due to memory and power limitations. The intent of this work …

Neurodevelopmental And Transient Impacts Of Brain Kynurenic Acid Elevation And Sleep-Wake Behavior, Katherine Rentschler

Theses and Dissertations

Sleep is vital for healthy cognition and mood. Sleep dysregulation is implicated in psychiatric disorders such as schizophrenia and bipolar disorder. Sex differences in sleep and arousal dysregulation are prominent in patients with psychotic disorders. Elevated levels of the neuroactive tryptophan metabolite, kynurenic acid (KYNA), have been found in cerebrospinal fluid and postmortem brain tissue samples from patients with psychotic disorders. KYNA is an astrocyte derived antagonist at N-methyl-D-aspartate (NMDA) glutamate receptors and α7 nicotinic acetylcholine (α7nACh) receptors. KYNA is synthesized in the brain from its biological precursor, kynurenine, via the enzyme kynurenine aminotransferase II (KAT II), a potential therapeutic …

Experimental Observation Of Sphere Symmetric Isolated Single Droplet Combustion In A Converging Channel, Mason Carrington Williams

Theses and Dissertations

Spherically symmetric isolated single droplet combustion has been observed mainly in microgravity conditions. This study sought to determine if spherically symmetric combustion can be produced in a lab-scale experiment using flow acceleration to counteract the effects of buoyancy. The experiment was conducted in a converging channel that decreased in width along its length to accelerate the flow and limit the formation of a boundary layer. The rate at which the area decreased was governed by the initial velocity condition set at the channel inlet.

The droplets were generated using a piezoelectric actuator which forced fuel out of an injector with …

Evaluation Of Preferential Vaporization Characteristics Of Isolated Single Droplet Combustion In A Converging Channel, Claire Elizabeth Dixon

Theses and Dissertations

Preferential vaporization of isolated single droplets was evaluated in this study. A previously verified lab-scale experiment using flow acceleration to counteract the effects of buoyancy in a converging channel with a decreasing cross section was utilized to investigate the single isolated droplet combustion. The previous experimentation revealed differences between results and values predicted by a one-dimensional numerical simulation. To investigate if the observed differences were the result of turbulent flow and the development of a boundary layer within the channel, a model was designed and analyzed in Ansys Fluent.

The developed Ansys simulation indicated that turbulent flow and growth of …

Advancing The Engineering Workforce By Enhancing Diversity, Equity, And Inclusion In The Engineering Classroom, Phoneia Hughes Myers

Theses and Dissertations

Society’s dependence on engineered products is steadily increasing. This dependence requires the engineering workforce to continually innovate and design new advancements. In pursuit of this, engineering employers are implementing diversity, equity, and inclusion initiatives to attract prime candidates and retain employees. For employers to achieve the goals of their initiatives, engineering colleges and universities must produce a diverse pool of graduates. The purpose of this thesis report is to investigate how the diversity, equity, and inclusion concept can be implemented into engineering education to assist with producing diverse graduating classes. A universal methodology is proposed to provide a roadmap on …

An Artificial Intelligence Approach To Fatigue Crack Length Estimation From Acoustic Emission Signals, Shane T. Ennis

Theses and Dissertations

As in service aircraft begin to age and fatigue, a method for evaluating the operational life they are currently operating under and have remaining comes into question. Structural health monitoring is (SHM) is a popular method of structural analysis with growing interest in the aerospace industry. SHM is capable of damage assessment and structural life estimations.

The ultimate goal of the research presented in this thesis is to develop a methodology of classifying the length of a fatigue crack though the use of machine learning. The thesis has three major chapters as described below.

The first chapter deals with the …

Comprehensive Process Planning Optimization Framework For Automated Fiber Placement, Alex Ryan Brasington

Theses and Dissertations

Advanced composite materials came about in 1966 and have since been widely used due to the possibility of superior structural performance while also achieving weight reductions. Such opportunities have led to composite materials being used to fabricate complex components, often in the aerospace sector. Most components, especially in aviation, are on a large scale and are outside the capabilities of traditional composite manufacturing techniques. Traditional manufacturing methods are also labor intensive, time consuming, have a high level of material scrap, and are prone to human error. This has led to the need for innovative manufacturing solutions to withstand the ever-increasing …

Development Of System Pressure Drop Calculation Methods For Dilute Phase Pneumatic Conveying, Ross Daniel Gorman

Theses and Dissertations

This work is focused on dilute and dense phase pneumatic conveying of bulk solids. The motivation of this work is to use industrial data to scale up existing models for pressure drop in pneumatic conveying systems, determine which models best predict pressure drop in full conveying systems, and find the empirical coefficients that go with these models.

Several major research objectives were accomplished by this work. First, system pressure drop methods were evaluated in this research. Other researchers have focused on single pipe section type pressure drops. Second, the data used in this research both for the machine learning evaluations …