Mechanical Engineering Commons^™

Optical Micro-Seismometer Based On Evanescent Field Perturbation Of Whispering Gallery Modes, Jaime Da Silva

Mechanical Engineering Research Theses and Dissertations

This thesis proposes a light-weight, compact, and accurate optical micro-seismometer that could be used in many applications, such as planetary exploration. The sensor proposed here is based on the principle of whispering gallery optical mode (WGM) resonance shifts of a dielectric micro-resonator due to disturbances of its evanescent field. The micro-seismometer could be used in place of the traditional bulky seismometers. The design of a waveguide-resonator and mechanical structure to disturb the evanescent field are presented. A proof-of-concept a seismometer model that uses a 5µm ring resonator is numerically tested with actual seismic data. The results show that a WGM-based …

Molecular Dynamics Studies On Nanoscale Confined Liquids, Alper Celebi

Mechanical Engineering Research Theses and Dissertations

Liquid transport in nanochannels have been attracting great interests, especially for last two decades, owing to its potential applicability in various fields including biochemistry, medical science and engineering. For exploring and generating new ideas in the field of nanofluidics, molecular simulation techniques have become an ideal way due to the experimental challenges impeding the field of nanofluidics in fabrication and measurements.

In this dissertation, we perform molecular dynamics simulations to investigate liquid transport behavior in nanoscale channels. The expanse of this dissertation concerns several fundamental topics in nanoscale liquid transport phenomena such as liquid properties in nanoscale confinements, interfacial flows …

My Catalyst, Gabrielle Gambino Lyon

Celebration of Learning

Over the course of my internship and shadow program with Pepper Lawson Construction and Ziegler Cooper Architects, I was able to explore the various career paths involved in the design, construction, and civil engineering fields. My work on the construction site of a high-rise apartment building located in the heart of Houston, TX allowed me first-hand experience working and learning alongside project engineers, contractors, building developers, and the construction team.

This project was the perfect confluence of my main areas of interest: structural, mechanical, civil, and environmental engineering, as well as architecture. My daily work consisted of on-site walk throughs, …

Powering A Biosensor Using Wearable Thermoelectric Technology, Anneliese Bals, Noah Barnes, Rafael Bravo, Nicolas Garcia, Joseph O'Bryan, Dylan Santana

Interdisciplinary Design Senior Theses

Wearable medical devices such as insulin pumps, glucose monitors, hearing aids, and electrocardiograms provide necessary medical aid and monitoring to millions of users worldwide. These battery powered devices require battery replacement and frequent charging that reduces the freedom and peace of mind of users. Additionally, the significant portion of the world without access to electricity is unable to use these medical devices as they have no means to power them constantly. Wearable thermoelectric power generation aims to charge these medical device batteries without a need for grid power.

Our team has developing a wristband prototype that uses body heat, ambient …

Enhancing Mobility And Independence Of Wheelchair Users, Briar Blake, Paul Nauleau

Interdisciplinary Design Senior Theses

Conditions as simple as a leg fracture or more severe impairments such as paralysis and stroke may confine a person to a wheelchair. Wheelchairs help people with limited mobility transport themselves to different locations, but do not help the person leave the wheelchair. Users would need to do this to enter a car, use the restroom, take a shower, and sit at a table comfortably with family. The following design is a wheelchair attachment that serves to provide the user with increased mobility and independence. Wheelchair users struggle to get into and out of their chairs due to the unassisted …

The Vessel For Autonomous Research Underwater (The Varuna), Tyler Briles, Shae Connor, Erin Guthrie, Anthony Jackson, Madeleine Peauroi

Interdisciplinary Design Senior Theses

Humans are intimately connected to the Earth’s ocean, and yet only 5% of it has been explored. Learning more about marine life and ocean chemistry can only improve our stewardship efforts. The addition of an Autonomous Underwater Vehicle to the Santa Clara University Robotic Systems Laboratory’s collection of marine robots will contribute to this quest for knowledge. It will assist researchers by providing a low-cost, easy-to-use, portable, reliable, and safe alternative to operator-controlled vehicles. This report describes our motivations for this project, the decisions we made in the design and manufacturing of the VARUNA, and tradeoff analyses of possible options. …

Soft-Microrobotics: The Manipulation Of Alginate Artificial Cells, Samuel Sheckman

Mechanical Engineering Research Theses and Dissertations

In this work, the approach to the manipulation of alginate artificial cell soft-microrobots, both individually and in swarms is shown. Fabrication of these artificial cells were completed through centrifugation, producing large volumes of artificial cells, encapsulated with superparamagnetic iron oxide nanoparticles; these artificial cells can be then externally stimulated by an applied magnetic field. The construction of a Permeant Magnet Stage (PMS) was produced to manipulate the artificial cells individually and in swarms. The stage functionalizes the permanent magnet in the 2D xy-plane. Once the PMS was completed, Parallel self-assembly (Object Particle Computation) using swarms of artificial cells in complex …

A Microresonator-Based Laser Doppler Velocity Sensor For Interplanetary Atmospheric Re-Entry, Benjamin Wise

Mechanical Engineering Research Theses and Dissertations

In this thesis, a laser velocity sensor concept based on optical microresonators is presented and the application to spacecraft atmospheric entry is explored. The concept is based on the measurement of Doppler shift of back-scattered laser light. Specifically, the Doppler shift is detected by observing the whispering gallery optical modes (WGM) of a dielectric microresonator excited by the back scattered light from particulates and gas molecules. The microresonator replaces the typical Fabry-Perot interferometer and CCD camera system, thereby significantly reducing the size and weight of the overall detection system. This thesis presents proof-of-concept results for this measurement approach. The Doppler …

Blunt And Ballistic Impacts On Human Head Models: An Analytical And Numerical Study, Yongqiang Li

Mechanical Engineering Research Theses and Dissertations

Head injuries, as a leading cause of death, have become a major health care issue for civilians and soldiers. There has been an urgent need to understand mechanisms of such injuries. The objective of this dissertation research is to study some head injuries and related mechanisms using analytical and computational models.

In Chapter 2, a new analytical (non-linear) model for the impact of a solid sphere on a fluid-filled spherical shell is developed by including the stress wave propagation effect in addition to the Hertzian contact deformations and the shell membrane and bending actions. A simplified (linearized) model incorporating the …

Advanced Manufacturing Of Titanium Alloys For Biomedical Applications, Nicholas C. Mavros

ETD Archive

In metallurgy, Titanium has been a staple for biomedical purposes. Its low toxicity and alloying versatility make it an attractive choice for medical applications. However, studies have shown the difference in elastic modulus between Titanium alloys (116 GPa) and human bone (40-60 GPa) contribute to long term issues with loose hardware fixation. Additionally, long term studies have shown elements such as Vanadium and Aluminum, which are commonly used in Ti-6Al-4V biomedical alloys, have been linked to neurodegenerative diseases like Alzheimers and Parkinsons. Alternative metals known to be less toxic are being explored as replacements for alloying elements in Titanium alloys. …

Non-Intrusive Optical Measurement Of Electron Temperature In Near Field Plume Of Hall Thruster, Peter J. Urban

ETD Archive

Currently there is a large interest in the use of more efficient means of propulsion in long term missions due to the costs and difficulties associated with placing and maintaining the needed fuel for conventional chemical systems in orbit. Mass reduction of upper stages will return large returns due to the great reduction in required lower stage fuel. Due to these factors, alternatives are undergoing active research, though this paper is concerned with the area of electrical propulsion. Electric propulsion is broadly defined as propulsion where the energization of the exhaust occurs via application of electromagnetic fields as opposed to …

Neuromuscular Reflex Control For Prostheses And Exoskeletons, Sandra K. Hnat

ETD Archive

Recent powered lower-limb prosthetic and orthotic (P/O) devices aim to restore legged mobility for persons with an amputation or spinal cord injury. Though various control strategies have been proposed for these devices, specifically finite-state impedance controllers, natural gait mechanics are not usually achieved. The goal of this project was to invent a biologically-inspired controller for powered P/O devices. We hypothesize that a more muscle-like actuation system, including spinal reflexes and vestibular feedback, can achieve able-bodied walking and also respond to outside perturbations. The outputs of the Virtual Muscle Reflex (VMR) controller are joint torque commands, sent to the electric motors …

Predictive Simulations Of Gait And Their Application In Prosthesis Design, Anne D. Koelewijin

ETD Archive

Predictive simulations predict human gait by solving a trajectory optimization problem by minimizing energy expenditure. These simulations could predict the effect of a prosthesis on gait before its use. This dissertation has four aims, to show the application of predictive simulations in prosthesis design and to improve the quality of predictive simulations. Aim 1 was to explain joint moment asymmetry in the knee and hip in gait of persons with a transtibial amputation (TTA gait). Predictive simulations showed that an asymmetric gait required less effort. However, a small effort increase yielded a gait with increased joint moment symmetry and reduced …

An Anisotropic Constitutive Model For Nuclear Grade Graphite, James Christopher

ETD Archive

Graphite material is used extensively in nuclear reactors however the material has a limited strain range for elastic behavior. This provides the motivation to derive a constitutive model that captures the inelastic deformations exhibited by this material. This dissertation first presents details of an isotropic constitutive model derived using continuum principles of engineering mechanics that accounts for different inelastic behavior in tension and compression. An inelastic dissipation function was developed using an integrity basis proposed by Green and Mkrtichian (1977) for the isotropic version of the model. This isotropic model was then extended to capture anisotropic stress-strain behavior using directional …

Sandia Senior Design Collaboration: Vacuum Sensor Design, James L. Valerio, Eric J. Black, Joseph P. Bednarz, David R. Warther

Williams Honors College, Honors Research Projects

Sandia National Laboratories has requested a fully mechanical device to close a circuit after launch has occurred and the device enters a vacuum. Intended for applications in rockets and missiles, the device must fit in a 36 degree wedge with a 6.8 inch radius that is 6 inches in height and be ready to bolt onto a rocket. The pressure switch must be prevented from actuating until a launch acceleration ranging from 20 to 27g is detected. The pressure switch must close the circuit after a pressure of 10^-1 Torr is reached and before a pressure of 10^{-6 …}

Identification Of Nonlinear Constitutive Properties Of Damping Coatings, Mackenzie E. Tidball

Browse all Theses and Dissertations

Scheduled and unscheduled maintenance actions are a significant cost for gas turbines. Advanced life prediction capabilities help to mitigate these costs. However, the protective thermal and damping coatings applied to the turbine rotors which can help significantly extend component life simultaneously increase the difficulty of modeling the behavior of the components due to the nonlinearity they introduce.This research approaches modeling and analysis of nonlinear coatings for turbine blades and blisks using a nonlinear constitutive law model for the coating. The theoretical frequency response of the nonlinear system is solved for using the harmonic balance method. The coefficients of the nonlinear …

Fabrication And Characterizations Of Lithium Aluminum Titanate Phosphate Solid Electrolytes For Li-Based Batteries, Anurag Yaddanapudi

Browse all Theses and Dissertations

Demands for electric vehicles and flexible electronics have escalated research in developing high-performance lithium batteries based on solid-state chemistry. The present work is to develop highly-conductive and flexible solid electrolyte for such applications. Lithium aluminum titanate phosphate (LATP or Li1.3Al0.3Ti1.7(PO4)3), both in ceramic pellets and free-standing composite membranes, have been fabricated. The crystal structure, surface morphology, and ionic conductivity are systematically studied. LATP pellets are prepared using solid state reaction approach. The results indicate that calcine temperature has significant impacts on the phase impurity and sintering temperature and duration have more impacts on the grain size and porosity of LATP …

Layer-To-Layer Physical Characteristics And Compression Behavior Of 3d Printed Acrylonitrile Butadiene Styrene Metastructures Fabricated Using Different Process Parameters, Sivani Patibandla

Browse all Theses and Dissertations

Three-dimensional (3D) printing, a subset of additive manufacturing, is currently being explored heavily for actual part fabrication due to its ability to create complex objects with intricate internal features. There are several 3D printing technologies; however, the extrusion-based technology such as fused deposition modeling (FDM) is the widely used one owing to its low cost. The FDM method can be used to fabricate parts with different fill densities, fill patterns, and process parameters such as extruder temperature and print speed. In this research, influence of process parameters such as extruder temperature and speed on the physical characteristics such as the …

Constitutive Modeling Of Creep In Leaded And Lead-Free Solder Alloys Using Constant Strain Rate Tensile Testing, Eric Thomas Stang

Browse all Theses and Dissertations

Environmental and safety concerns have necessitated a phase-out of lead-based alloys, which are often used in electronics solder applications. In order to properly assess suitable replacement materials, it is necessary to understand the deformation mechanisms relevant to the application. In the case of electronics solder, creep is an important mechanism that must be considered in the design of reliable devices and systems. In this study, Power-Law and Garofalo constitutive creep models were derived for two medium temperature solder alloys. The first alloy is known by the commercial name Indalloy 236 and is a quaternary alloy of lead, antimony, tin, and …

Effect Of Process Parameters On The Surface Roughness And Mechanical Performance Of Additively Manufactured Alloy 718, Bo Ryan Whip

Browse all Theses and Dissertations

Metal additive manufacturing (AM) is a method to create complex components in a layer-by-layer process. Currently, there is a lack of understanding in the processing-structure-properties-performance relationship, particularly related to defects inherent to the AM process. This work investigates the relationship of process parameters, as-built surface roughness, and mechanical performance for nickel-based superalloy 718 built using laser powder bed fusion. The surface roughness of components built using varied processing parameters was characterized using both nondestructive and destructive measurement techniques. Finite element analysis was used to study the stress concentration on surface profiles. Statistical correlations are presented between contour processing parameters and …

Micro-Architectured Metamaterials: Design And Analysis, Li Ai

Mechanical Engineering Research Theses and Dissertations

Metamaterials are engineered materials with unusual properties deriving mainly from their micro-architectures rather than composition. They have attracted increasing attention owing to their tailorable multi-functional properties that cannot be exhibited by naturally-occurring or traditionally-manufactured materials. Materials with a negative Poisson’s ratio (PR) and materials with a non-positive coefficient of thermal expansion (CTE) are examples of mechanical metamaterials. In this dissertation, metamaterials with negative Poisson’s ratios and negative coefficients of thermal expansion are designed using both heuristic approaches and topology optimization methods.

Firstly, based on a star-shaped re-entrant structure, three two-dimensional (2-D) periodic cellular materials are developed, which can be tailored …

Multiple Consecutive Recapture Of Rigid Nanoparticles Using A Solid-State Nanopore Sensor, Jungsoo Lee

Mechanical Engineering Research Theses and Dissertations

Solid‐state nanopore sensors have been used to measure the size of a nanoparticle by applying a resistive pulse sensing technique. Previously, the size distribution of the population pool could be investigated utilizing data from a single translocation, however, the accuracy of the distribution is limited due to the lack of repeated data. In this study, we characterized polystyrene nanobeads utilizing single particle recapture techniques, which provide a better statistical estimate of the size distribution than that of single sampling techniques. The pulses and translocation times of two different sized nanobeads (80 nm and 125 nm in diameter) were acquired repeatedly …

Cancer Diagnosis By Bioimpedance Spectroscopy And Computer-Assisted Pattern Recognition, Shahriar Shams

Mechanical Engineering Research Theses and Dissertations

The field of cancer diagnostics has always been one of the most complex and challenging areas in biomedical research, and there has been an increasing demand for more advanced clinical diagnostic equipment over the past four decades. In this thesis, a custom-made coaxial bioimpedance sensor was used, in combination with computer-aided pattern recognition tools, to identify cancer in tissue samples obtained from the formalin-fixed kidney of a 60 year-old male patient. Impedance data was collected using the coaxial sensor at 401 logarithmically-spaced frequency points ranging from 10 kHz to 100 MHz. Principle Component Analysis and Naive Bayes Classification techniques were …

Beta: Bioprinting Engineering Technology For Academia, Max Abrams, Jeffrey Barone, Cynthia Le, Jacob Ososke, Franz Plum, Emily Takimoto, Josie Warren

Interdisciplinary Design Senior Theses

Higher STEM education is a field of growing potential, but too many middle school and high school students are not testing proficiently in STEM subjects. The BETA team worked to improve biology classroom engagement through the development of technologies for high school biology experiments. The BETA project team expanded functionality of an existing product line to allow for better student and teacher user experience and the execution of more interesting experiments. The BETA project’s first goal was to create a modular incubating Box for the high school classroom. This Box, called the BETA Box was designed with a variety of …

Scu Cube, Matt Condino, Andrew Drape, Evan Eberhardt, Cooper Mcdonnell, Brayton Mcknight, Isaac Mcquillen, James Olwell, Laura Tschudy

Interdisciplinary Design Senior Theses

Traditional forms of communication such as landlines and cell phones are unreliable during disaster scenarios. It is difficult to coordinate relief efforts in the aftermath of a disaster due to the unavailability of reliable communication methods. The SCUCube is a 3U CubeSat designed to aid disaster relief communications. The satellite has an amateur radio primary payload that can send and receive standardized data packets with compatible radios, and also has an experimental attitude control system secondary payload. The semi-passive attitude control system uses a gravity gradient boom and a reaction wheel to stabilize the orientation of the satellite. In addition, …

Dynamic Modeling And Simulation Of A Variable Cycle Turbofan Engine With Controls, Robert W. Buettner

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Next generation aircraft (especially combat aircraft) will include more technology and capability than ever before. This increase in technology comes at the price of higher electrical power requirements and increased waste heat that must be removed from components to avoid overheating induced shutdowns. To help combat the resulting power and thermal management problem, a vehicle level power and thermal management design and optimization toolset was developed in MATLAB®/Simulink®. A dynamic model of a three-stream variable cycle engine was desired to add to the capabilities of the power and thermal management toolset. As an intermediate step to this goal, the dynamic …

Forming A Metal Matrix Nanocomposite (Mmnc) With Fully Dispersed And Deagglomerated Multiwalled Carbon Nanotubes (Mwcnts), Mahesh Kumar Pallikonda

ETD Archive

Carbon Nanotubes (CNTs) with their exceptional properties will facilitate the Metal matrix composites (MMC) to exhibit good mechanical properties, thermal and electrical conductivities, corrosion resistance, etc. The critical factor that holds the development of the Metal matrix Nanocomposites (MMNC) by using CNTs is the tendency of CNTs to form clusters (agglomerations) due to their high Van der Waals attractions. Due to this factor, low density and other properties of the CNTs, there has been a delay in harnessing their ultimate potential.
Existing literature in contemporary times from the works of few researches in Nanocomposites shows the prevalence of using surfactants …

Design And Control Of A Powered Rowing Machine With Programmable Impedance, Jose Humberto De La Casas Zolezzi

ETD Archive

Due to the rise of obesity, diabetes and cardiovascular disease, research in human performance and physical activity has received increased attention. Rowing machines are used for performance improvements through concentric exercises, however a combination of concentric and eccentric actions is known to improve the effectiveness of training. In this work, a conventional rowing machine was modified to include an electric motor and a robust impedance control system, enabling programmable impedance with concentric and eccentric capabilities. Eccentric exercises are known to contribute significantly to the efficacy of training and to diminish the detrimental effects of humans operating in microgravity for long …

Skintronics: Wireless, Skin-Wearable Electronics For Monitoring Of Electrocardiogram, Matthew B. Piper, Woon-Hong Yeo, Yongkuk Lee

Undergraduate Research Posters

The ECGs I micro-fabricate are designed to be flexible, stretchable and wireless circuits that can be applied to the skin directly. The device is encased in a conformal, silicon-like substrate, that allows the ECG to be attached with the electrodes. Each electrode has been previously measured and verified that it will be correctly placed for an accurate reading. Prototyping this ECG/electrode device allows the user to mount the prototype directly to the patient without having to attach and wire ten other electrodes. This prototype solves the issue that comes about when a doctor, nurse or emergency medical technician must attach …

Swagelok's Hand Tube Bender, Chapin Hutama, Seth Bills, William Mcconnell, Tyler Brown

Williams Honors College, Honors Research Projects

In our project, we are assigned to develop a hand tube bender that is able to bend medium, high pressure, and standard 1/4” and 3/8” tubing. The bender also shall be capable of being used with two hands without the aid of a bench vise and have provisions for use in a bench vise for convenience. The bender shall not damage the tube during bending and induce a maximum of 8% ovality in the bent tubing. In addition, the cost of the bender shall be less than the existing hand tube bender and be resistant to rusting from ordinary use. …