Mechanical Engineering Commons^™

Computational Simulation Of The Paw-04 Nozzle Configuration, Juan Hernandez

Honors Theses

The research was based on the 4th Propulsion Aerodynamics Workshop which was organized by the American Institute of Aeronautics and Astronautics (AIAA) Air Breathing Propulsion System Integration Technical Committee and its objective was to assess the accuracy and numerical prediction capabilities of Computational Fluid Dynamics (CFD). It focused on the work of Behrouzi and McGuirk where they tested two different nozzle configurations under set boundary conditions. The nozzle configurations included a high aspect ratio rectangular nozzle with a clean exit and the same nozzle with an aft-deck attached to the exit. Three different unstructured grids were generated for the clean …

The Effect Of Soil Saturation On The Heat Transfer Rate In A Controlled Environment For Application To Ground Source Heat Pumps, William Barnard

Honors Theses

With the worldwide push for environmentally friendly technology, the topic of geothermal systems has only become more important. Ground Source Heat Pumps (GSHPs) are heat pumps that take advantage of the natural temperature difference between the soil and the air to decrease the amount of power necessary to heat an area. A GSHP has been shown to be capable of increasing efficiency by 3 or 4 times the amount of a conventional heating and cooling system [4]. To take advantage of the full capabilities of a GSHP, one needs to understand what factors can increase or decrease efficiency. While research …

Universal Bike Suspension Design, Ernesto Huerta, Gregory Ryan Ritter, Chris Michael Fedor, Michael Wu

Mechanical Engineering

Cal Poly Bike Builders (CPBB) is a student club at Cal Poly helping students design and fabricate their own bicycles. Currently, club members build rigid frames and mountain bikes with only front-suspension–commonly referred to as a “hardtail”. As more students join the club, interest grows in building full-suspension mountain bikes (FSMTB). Designing and manufacturing a mountain bike rear-suspension system requires a diverse skillset and a substantial time commitment. As a result, individual efforts building FSMTB have proven unsuccessful. The scope of this project is to develop a defined method and necessary tools such that all CPBB members can efficiently build …

A Study On Ultrasonic Energy Assisted Metal Processing : Its Correeltion With Microstructure And Properties, And Its Application To Additive Manufacturing., Anagh Deshpande

Electronic Theses and Dissertations

Additive manufacturing or 3d printing is the process of constructing a 3-dimensional object layer-by-layer. This additive approach to manufacturing has enabled fabrication of complex components directly from a computer model (or a CAD model). The process has now matured from its earlier version of being a rapid prototyping tool to a technology that can fabricate service-ready components. Development of low-cost polymer additive manufacturing printers enabled by open source Fused Deposition Modeling (FDM) printers and printers of other technologies like SLA and binder jetting has made polymer additive manufacturing accessible and affordable. But the metal additive manufacturing technologies are still expensive …

Secondary Resonances Of Electrostatically Actuated Mems Cantilevers, Christopher I. Reyes

Theses and Dissertations

In this work the behavior of micro-electromechanical (MEMS) cantilever resonators is investigated. The cantilever resonators are electrostatically actuated with hard AC voltage resulting in nine distinct resonances cases including super and subharmonic resonances. The amplitude frequency and amplitude voltage bifurcation diagrams are obtained for each of the nine resonance cases. Reduced order models (ROMs) are developed to include one and two modes of vibration. Three different methods are used to solve the ROMs namely 1) the method of multiple scales (MMS), which is a perturbation method used for one mode of vibration, 2) the homotopy analysis method (HAM), which is …

Numerical Investigation Of Coalescence-Induced Self-Propelled Behavior Of Droplets On Non-Wetting Surfaces And Wedged Surfaces., Yan Chen

Electronic Theses and Dissertations

When small drops coalesce on a superhydrophobic surface, the merged drop can jump away from the surface due to the surface energy released during the coalescence. This self-propelled behavior has been observed on various superhydrophobic surfaces and has potential applications in areas related to the heat and mass transfer, such as heat exchangers, anti-icing and anti-frost devices, thermal management and water harvesting. The jumping velocity model was obtained based on published experimental data and the balance of various energy terms described in previous studies. However, the self-propelled mechanism is still not fully understood. In this study, the self-propelled droplet phenomenon …

Methods To Remotely Eliminate Biofilm From Medical Implants Using 2.4 Ghz Microwaves, Brett Glenn

Mechanical Engineering Undergraduate Honors Theses

Infections associated with biofilm growth are usually challenging to eradicate due to their high tolerance toward antibiotics [11, 12]. Biofilms often form on the inert surfaces of medically implanted devices [13]. No matter the sophistication, microbial infections can develop on all medical devices and tissue engineering constructs [12]. Related infections lead to 2 million cases annually in the U.S., costing the healthcare system over $5 billion in additional healthcare expenses [12].

Novel solutions to biofilm’s microbial colonization span the spectrum of engineering and science disciplines. Yet a practical solution still does not exist. The research presented here will explore a …

Challenges And Opportunities Of Layered Cathodes Of Linixmnyco(1-X-Y)O2 For High-Performance Lithium-Ion Batteries, Jason Frank

Mechanical Engineering Undergraduate Honors Theses

High energy density lithium-ion batteries (LIBs) are widely demanded for portable electronic devices and electrical vehicles. Layered-structure LiCoO₂ oxide (LCO) has been the most commonly used cathode material in commercial LIBs. Compared to LCO, LiNi_1-x-yMn_xCo_yO₂ (NMC) cathodes are particularly attractive due to their reduced cost and higher capacity. Among the NMC cathodes, nickel-containing LiNi_0.5Co_0.3Mn_0.2O₂ (NMC532) is one of the most promising cathode materials undergoing intensive investigation, but suffers from a series of technical issues, such as structural instability, performance fading, and safety issues. In this …

3d Printing A Microfluidic Chip Capable Of Droplet Emulsion Using Ninjaflex Filament, Robert Andrews

Mechanical Engineering Undergraduate Honors Theses

This paper details an investigation into methods and designs of 3D printing a microfluidic system capable of droplet emulsion using NinjaFlex filament. The specific field in which this paper’s experiment is rooted is dubbed “BioMEMS,” short for bio microelectromechanical systems. One prominent research area in BioMEMS is developing a “lab on a chip.” Essentially, the goal is to miniaturize common lab processes to the micro scale, rendering it possible to include these processes in a small chip. Reducing necessary sample sizes, shortening the reaction times of lab processes, and increasing mobility of lab processes can all be realized through microfluidic …

Development Of Small-Scale And Low-Power Attitude Determination System For Nanoscale Satellites By Infrared Earth-Imaging Sensors, Zachary Tolar

Mechanical Engineering Undergraduate Honors Theses

Many space missions require that the spacecraft be oriented in a specific direction to operate correctly. ARKSAT 1, the University of Arkansas’s first satellite, is a 1U CubeSat designed to perform atmospheric spectroscopy from Low-Earth Orbit and as such requires precise attitude determination and control. Currently, attitude determination systems for 1U CubeSats with small space, low power, and low cost restrictions do not exist. This paper discusses the development of an earth-imaging infrared camera system for attitude determination on CubeSats and SmallSats that meets these requirements. Melexis MLX 90640 IR arrays and Microchip 8-bit microcontrollers are used to create infrared …

Modelling Palladium Decorated Graphene Using Density Functional Theory To Analyze Hydrogen Sensing Application, Sameer Kulkarni

Mechanical Engineering Undergraduate Honors Theses

Graphene is an exciting new material with many promising applications. One such application of graphene is gas sensing, when adsorbed with transition metals, notably Palladium. Therefore, it is of paramount importance to have appropriate ab initio calculations to calculate the various properties of graphene under different adsorbates and gasses. The first step in these calculations is to have a functioning base Density Functional Theory (DFT) model of pristine graphene decorated with Palladium. The computational methods described in this paper has yielded results for pristine graphene that have been confirmed many times in previous experimental and theoretical studies. Future work needs …

Design Of A Scara Based Mobile 3d Printing Platform, Zachary Hyden

Mechanical Engineering Undergraduate Honors Theses

Currently 3D printers rely heavily on people to run them, there is no automatic way to start a new print after one has finished. On top of this 3D printers are limited in the area they can print on. Even though the additive manufacturing market is rapidly growing and is increasingly being used in product manufacturing there has yet to be a solution to this problem. This research proposes using mobile 3D printing robots to solve both of these issues. The proposed prototype utilizes a Selective Compliance Assembly Robot Arm (SCARA) based robot capable of cooperatively manufacturing parts. This allows …

A Game Theory Motivated Approach To Analyzing Modularity In Automotive Systems, David John Thiess Jr.

Theses and Dissertations

This paper examines the effect of integrated and modular design on consumers and manufacturers and seeks to determine if there is an optimal design that benefits both. Some consumers perceive the automotive industry to design vehicles with only the company’s benefit in mind, rather than the desires of the consumer. However, the automotive industry seeks to please consumers, while minimizing the cost of production. A game-theoretic based model was developed that was used to determine if there existed a level of modularity for a system that optimized for both the manufacturer and consumer. The game model consisted of two players, …

Hardware-In-The-Loop Testbed For The Dynamics Of Spacecraft Rendezvous And Capture, Stephen Thiam Choy Kwok Choon

Theses and Dissertations

As more satellites are launched into orbit, the amount of space debris objects and defunct satellites in orbit that pose a risk to existing operational space systems is expected to grow. In addition, the risk of collision with defunct systems and space debris increase operational fuel cost for active satellites that have to perform avoidance maneuvers. When a satellite’s propulsion or attitude navigation system malfunction, this may cause the satellite to become defunct, potentially becoming a risk to other active space systems. A way to counter defunct satellite systems, is through robotic on-orbit servicing and active space debris removal as …

Experimental And Numerical Analysis Of The Drag Force On Surfboards With Different Shapes, Omar Lahlou

Theses and Dissertations

The aim of the present study is to define the hydrodynamic resistance of surfboards with different designs. Decreasing the drag acting on a board helps the surfer to attain higher surfing performances. It helps to attain higher speeds and maneuvering for the surfer. In this thesis, theoretical, experimental and computational approaches are used to explain how the drag changes with different surfboard shapes. Four surfboards with varying shapes were towed at different speeds and the resulting force was recorded. Two computational models were developed using Star CCM and Flowsquare to confirm the experimental results. The drag force on the boards …

Design Of A Bedside Walker-Cane Hybrid To Aid Senior Adults Avoid Falls During Night Walks, Jorge L. Gutierrez

Theses and Dissertations

The objective of this research and development work is to design a device to help senior adults prevent fall during night walks indoors. The problem of elders falling at a night setting was found to be caused by the multiple environmental and medical conditions. The target demographic was found to be seniors from age 65 and older. Several occupational therapists and two physical therapists were consulted to gain knowledge on elders' behavior, possible improvements on current existing devices, and feedback regarding the early prototype built. Several products and patents were researched with a lack of findings on similar products that …

Biomechanics Of Lower Limb During The Golf Swing Using Opensim Modeling, Andrew B. Butler

Theses and Dissertations

The purpose of this research is to investigate the biomechanics of the lower-limb using an inverse dynamics model. Experimental data, recorded by an integrated Motion Analysis – Force Plate System in the UTRGV Biomechanics Laboratory, is used to determine ground reaction forces and marker trajectories. OpenSim, a graphical musculoskeletal and computational platform, is used to model the body in three dimensions. The human body is modeled as a 12-segment linkage, consisting of 23 degrees-of-freedom and 92 muscles. The experimental data for the Biomechanics Laboratory is imported in OpenSim. Then, joint angles, generalized coordinates & accelerations of lower-limb segments, muscle forces, …

Experimental Study Of Condensation In Different 3d Printed Regenerators In A Thermoacoustic Cooler, Aibek Bekkulov

Theses and Dissertations

Thermoacoustics (TA) deals with the conversion of heat into sound and vice versa. Device that converts heat into acoustic work is called TA heat engine, while the device that transfers energy from a low temperature reservoir to a high temperature one by utilizing acoustic work is called TA cooler. A simple construction of TA cooler includes an acoustic speaker, a resonator tube and a regenerator stack in which the temperature gradient is being imposed. Such a TA cooler has several advantages over traditional compression/expansion cooling machine such as its simplicity of the construction, high reliability and lack of toxic refrigerants. …

Development Of Flexible Photo-Mechanoluminescent Polymeric Based Systems, Carlos Hernandez

Theses and Dissertations

The project focuses on the creation of nanofiber systems with enhanced photo-mechanoluminescent response and high mechanical flexibility to further enhance promising optical applications. Lanthanide-Polyvinyl Di-Fluoride fiber systems were created using centrifugal spinning and characterized using SEM, FTIR, XPS, DSC, XRD, and PL. Fibers luminescence response was gotten when induced by ultraviolet light and the application of an impact force.

Polymeric Pvdf Fibers For Piezoelectric Applications In Energy Harvesting, Misael E. Martinez

Theses and Dissertations

This work focuses on developing and characterizing the piezoelectric response of Cerium doped Polyvinylidene Fluoride (PVDF) fine fibers and the effects of dopants and alignment on the formation of the β-phase and consequently on the piezoelectric performance. Six sets of fiber mats were prepared varying the concentration (2.5–7.5wt%) of Cerium (III) Nitrate-Hexahydrate and Ammonium-Cerium (IV) Sulfate-Dihydrate. Fiber mats were developed using the Forcespinning® technique and the angular velocity and dopant concentration were adjusted to obtain a synergy between fiber yield and fiber diameter. Fourier Transform Infrared Spectroscopy showed a significant enhancement in the PVDF β-phase and inhibition of the non-polar …

Blockchain Technology Based Supply Chain Systems And Supply Chain Performance: A Resource-Based View, Madhavi Latha Nandi

Theses and Dissertations

Blockchain technology (BCT) is set to transform firms’ present ways of managing supply chains. This thesis explores how the efforts by firms to integrate BCT into their supply chain systems and activities, can enable certain supply chain capabilities and subsequently, improve supply chain performance. Using an abductive research approach, qualitative content analyses of 126 cases of firms’ efforts in BCT-based supply chain systems (BCT-SCS) across multiple industries are conducted to identify the BCT-enabled supply chain capabilities and their performance outcomes. Findings reveal that the present BCT-SCS efforts are mainly oriented towards improving the operational-level capabilities namely, information sharing and coordination …

Vibration Reduction Of Mistuned Bladed Disks Via Piezoelectric-Based Resonance Frequency Detuning, Garrett Lopp

Electronic Theses and Dissertations

Recent trends in turbomachinery blade technology have led to increased use of monolithically constructed bladed disks (blisks). Although offering a wealth of performance benefits, this construction removes the blade-attachment interface present in the conventional design, thus unintentionally removing a source of friction-based damping needed to counteract large vibrations during resonance passages. This issue is further exacerbated in the presence of blade mistuning that arises from small imperfections from otherwise identical blades and are unavoidable as they originate from manufacturing tolerances and operational wear over the lifespan of the engine. Mistuning is known to induce vibration localization with large vibration amplitudes …

Lithium Molybdate-Sulfur Battery., Ruchira Ravinath Dharmasena

Electronic Theses and Dissertations

Rechargeable energy storage systems play a vital role in today’s automobile industry with the emergence of electric vehicles (EVs). In order to meet the targets set by the department of energy (DOE), there is an immediate need of new battery chemistries with higher energy density than the current Li- ion technology. Lithium–sulfur (Li–S) batteries have attracted enormous attention in the energy-storage, due to their high specific energy density of 2600 Wh kg^-1 and operational voltage of 2.0 V. Despite the promising electrochemical characteristics, Li-S batteries suffer from serious technical challenges such as dissolution of polysulfides Li₂S_{x …}

Additive Manufacturing Of High Performance Flexible Thermoelectric Generators Using Nanoparticle Inks, Tony Valayil Varghese

Boise State University Theses and Dissertations

Flexible thermoelectric devices are attractive power sources for the growing demand of flexible electronics and sensors. Thermoelectric generators have an advantage due to no moving parts, silent operation and constant power production with a thermal gradient.

Conventional thermoelectric devices are rigid and fabricated using complex and relatively costly manufacturing processes, presenting a barrier to increase the market share of this technology. To overcome such barriers, this work focuses on developing near ambient-temperature flexible thermoelectric generators using relatively low-cost additive manufacturing processes. A screen printable ink was developed for transforming nanoparticle ink into high-performance flexible thermoelectric generators with a peak thermoelectric …

A Mixed Method Study On The Impact Of Industry Sponsored Projects On Senior Capstone Design Student’S Motivational Factors, Devanshi Shah

Theses and Dissertations

This thesis examines the change in student motivation through a yearlong senior capstone design course with respect to their choice of project type. The senior capstone design projects offered at the university fall into one of two major project types: industry sponsored and nonindustry sponsored. The students opt for either of the two major project types based on their interest and future career goals. The students were given an adapted version of Motivated Strategies for Learning Questionnaire (MSLQ) to self-identify their motivation levels by rating various questions on a 7-point Likert scale. The surveys were conducted at two different points …

Final Design Report For Human Powered Vehicle Drivetrain Project, Derek Fromm, Luke Opitz, Michael Juri, Olivier Côté

Mechanical Engineering

The Cal Poly Human Powered Vehicle Club is building a bike to surpass 61.3 mph in 2019. The club and their mentor, George Leone, have proposed a senior project to design, build, and test the drivetrain for this year’s human powered vehicle. Research into human powered vehicles and their drivetrains has shown that the power that a rider can output and the efficiency at which the rider can pedal depend extensively on the design of the drivetrain. Despite the existence of standard bicycle drivetrain designs, the senior project team has found that the best design to meet the club’s requirements …

Thermal Gradient Characterization And Control In Micro-Fabricated Gas Chromatography Systems, Austin Richard Foster

Theses and Dissertations

In order to make gas chromatography (GC) more widely accessible, considerable effort has been made in developing miniaturized GC systems. Thermal gradient gas chromatograpy (TGGC), one of the heating methods used in GC, has recieved attention over the years due to it's ability to enhance analyte focusing. The present work seeks to develop high performance miniaturized GC systems by combining miniaturized GC technology with thermal gradient control methods, creating miniaturized thermal gradient gas chromatography (µTGGC) systems. To aid in this development a thermal control system was developed and shown to successfully control various µTGGC systems. DAQ functionality was also included …

Tuning Of The Zero Dispersion Point For Micro Electrical Mechanical Systems, Rebekah Mercedes Blackwell

Theses and Dissertations

Resonant micro-electromechanical systems (MEMS) are increasingly common in applications, including inertial sensors and frequency sources. These devices operate at resonance and take advantage of their size, ability to integrate with electronics, and light damping. The performance of these devices can be improved by operation at higher vibration amplitudes, but they often begin to exhibit frequency shifts near resonance as the amplitude is increased, due to nonlinear stiffness effects. Previous works have sought to balance nonlinearities in order extend the linear dynamic range (LDR) of these resonators. The focus of this thesis is to characterize, for design purposes, another possible operating …

Energy, Exergy And Economic Analysis Of A Micro-Cchp System, Ganesh Vinayak Doiphode

Theses and Dissertations

Combined cooling, heating and power generation (CCHP) systems can be utilized for commercial or multi-family residential buildings as efficient and reliable means to satisfy building power requirements and thermal loads. In the present study, a CCHP system consist of a Bryton cycle, an Organic Rankine cycle (ORC) and an absorption Ammonia-water cycle is considered. A detailed model is developed via MATLAB to assess the performance of the considered cycle from energy, exergy and economic perspectives. Appropriate ranges for inputs are considered and the first law efficiency, second law efficiency and ECOP of the cycle are determined as 77.17%, 33.18% and …

Acceleration, Braking, And Steering Controller For Polaris Gem E2, Matthew Benton Salfer-Hobbs

Theses and Dissertations

This paper discusses the design and simulation of lane keeping and velocity controllers for a Polaris GEM e2. The controllers were designed to be implemented in Florida Institute of Technology’s entry for the Intelligent Ground Vehicle Competition self-drive challenge. The software and physical implementation of actuators were included to control the acceleration, braking, and steering. The accelerator pedal was replaced with a set of digitally controlled potentiometers, the brake pedal was replaced with a linear actuator, and the steering column was replaced with a stepper motor. Each actuator was controlled by a Raspberry Pi 3. A sliding mode controller was …