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Development Of Confocal Imaging Techniques For Probing Interfacial Dynamics In Microscale, Gas-Liquid, Two-Phase Flow, Joseph E. Hernandez

Dissertations, Master's Theses and Master's Reports - Open

Micro-scale, two-phase flow is found in a variety of devices such as Lab-on-a-chip, bio-chips, micro-heat exchangers, and fuel cells. Knowledge of the fluid behavior near the dynamic gas-liquid interface is required for developing accurate predictive models. Light is distorted near a curved gas-liquid interface preventing accurate measurement of interfacial shape and internal liquid velocities. This research focused on the development of experimental methods designed to isolate and probe dynamic liquid films and measure velocity fields near a moving gas-liquid interface. A high-speed, reflectance, swept-field confocal (RSFC) imaging system was developed for imaging near curved surfaces.

Experimental studies of dynamic gas-liquid …

Use Of An Electrical Impedance Tomography Method To Detect And Track Fractures In A Gelatin Medium, Evan G. Lucas

Dissertations, Master's Theses and Master's Reports - Open

Electrical impedance tomography is applied to the problem of detecting, locating, and tracking fractures in ballistics gelatin. The hardware developed is intended to be physically robust and based on off-the-shelf hardware. Fractures were created in two separate ways: by shooting a .22 caliber bullet into the gelatin and by injecting saline solution into the gelatin. The .22 caliber bullet created an air gap, which was seen as an increase in resistivity. The saline solution created a fluid filled gap, which was seen as a decrease in resistivity. A double linear array was used to take data for each of the …

A Study Of Passenger Car Acoustic Cavity Boom Simulation Methods, Shreerang Dhabe

Dissertations, Master's Theses and Master's Reports - Open

The project objective is the study of acoustic boom phenomenon at 40 Hz in Chevrolet Cruze LTZ and recommend modeling techniques to improve accuracy of model prediction. Acoustic boom is caused by solid-fluid interaction between car structure and air inside the car cavity.

In this report, finite element analysis software Abaqus 6.12-3 is used to simulate the acoustic-structural coupling. The structural and acoustic mesh for the Chevrolet Cruze LTZ are fully coupled and solved using Abaqus ‘strongly coupled’ solution. In order to understand the physics of acoustic boom in a car simple car box models were designed. Simple box car …

Thickness Measurement Of Dynamic Thin Liquid Films Generated By Plug-Annular Flow In Non-Wetting Microchannels, David C. Deisenroth

Dissertations, Master's Theses and Master's Reports - Open

Surface tension forces are significant at millimeter length-scales, causing profoundly different flow morphologies in microchannels than in macroscale flows. The existence and morphology of thin liquid films is particularly relevant for predicting performance and operational stability of devices containing microscale two phase flows. Analytical, computational, and experimental methods previously employed in the study of thin liquid films are discussed. Thicknesses before and after a novel film morphology, referred to as a `shock,' are measured with a novel film thickness measurement technique that uses confocal microscopy. Film thicknesses predicted by previous work are compared to experimental results. Methods for increasing the …

Reconciling Function- And Affordance-Based Design, Benjamin T. Ciavola

Dissertations, Master's Theses and Master's Reports - Open

Traditional engineering design methods are based on Simon's (1969) use of the concept function, and as such collectively suffer from both theoretical and practical shortcomings. Researchers in the field of affordance-based design have borrowed from ecological psychology in an attempt to address the blind spots of function-based design, developing alternative ontologies and design processes. This dissertation presents function and affordance theory as both compatible and complimentary. We first present a hybrid approach to design for technology change, followed by a reconciliation and integration of function and affordance ontologies for use in design. We explore the integration of a standard function-based …

An Assessment Of Flow Regime Maps And A Numerical Heat Transfer Correlation For The Stratified/Annular Regime Of Shear-Driven Internal Condensing Flows, Fnu Nikhil Shankar

Dissertations, Master's Theses and Master's Reports - Open

Several modern-day cooling applications require the incorporation of mini/micro-channel shear-driven flow condensers. There are several design challenges that need to be overcome in order to meet those requirements.

The difficulty in developing effective design tools for shear-driven flow condensers is exacerbated due to the lack of a bridge between the physics-based modelling of condensing flows and the current, popular approach based on semi-empirical heat transfer correlations. One of the primary contributors of this disconnect is a lack of understanding caused by the fact that typical heat transfer correlations eliminate the dependence of the heat transfer coefficient on the method of …

Density Of Amorphous Carbon By Using Density Functional Theory, Sorayot Chinkanjanarot

Dissertations, Master's Theses and Master's Reports - Open

Amorphous carbon has been investigated for a long time. Since it has the random orientation of carbon atoms, its density depends on the position of each carbon atom. It is important to know the density of amorphous carbon to use it for modeling advance carbon materials in the future. Two methods were used to create the initial structures of amorphous carbon. One is the random placement method by randomly locating 100 carbon atoms in a cubic lattice. Another method is the liquid-quench method by using reactive force field (ReaxFF) to rapidly decrease the system of 100 carbon atoms from the …

Improving Startability And Reducing Emissions In Flexfuel Spark Ignition Direct Injection Variable Cam Timing Engine, Vaibhav S. Kale

Dissertations, Master's Theses and Master's Reports - Open

Experimental work and analysis was done to investigate engine startup robustness and emissions of a flex-fuel spark ignition (SI) direct injection (DI) engine. The vaporization and other characteristics of ethanol fuel blends present a challenge at engine startup. Strategies to reduce the enrichment requirements for the first engine startup cycle and emissions for the second and third fired cycle at 25°C ± 1°C engine and intake air temperature were investigated.

Research work was conducted on a single cylinder SIDI engine with gasoline and E85 fuels, to study the effect on first fired cycle of engine startup. Piston configurations that included …

Measuring Head Impact Contact Pressure In Collegiate Football Games To Correlate Head Kinematics To Brain Kinetics Elucidating Brain Injury Dynamics, Chandrika S. Abhang

Dissertations, Master's Theses and Master's Reports - Open

Does a brain store thoughts and memories the way a computer saves its files? How can a single hit or a fall erase all those memories? Brain Mapping and traumatic brain injuries (TBIs) have become widely researched fields today. Many researchers have been studying TBIs caused to adult American football players however youth athletes have been rarely considered for these studies, contradicting to the fact that American football enrolls highest number of collegiate and high-school children than adults. This research is an attempt to contribute to the field of youth TBIs.

Earlier studies have related head kinematics (linear and angular …

An Investigation Of Variable Valve Timing Effects On Hcci Engine Performance, Hrishikesh Abhay Saigaonkar

Dissertations, Master's Theses and Master's Reports - Open

The Homogeneous Charge Compression Ignition (HCCI) engine is a promising combustion concept for reducing NO_x and particulate matter (PM) emissions and providing a high thermal efficiency in internal combustion engines. This concept though has limitations in the areas of combustion control and achieving stable combustion at high loads. For HCCI to be a viable option for on-road vehicles, further understanding of its combustion phenomenon and its control are essential. Thus, this thesis has a focus on both the experimental setup of an HCCI engine at Michigan Technological University (MTU) and also developing a physical numerical simulation model called the …

Test-Analysis Model Correlation And Calibration Of A Multi-Component Plastic Part, Steven P. Carter

Dissertations, Master's Theses and Master's Reports - Open

The goal of this project is to learn the necessary steps to create a finite element model, which can accurately predict the dynamic response of a Kohler Engines Heavy Duty Air Cleaner (HDAC). This air cleaner is composed of three glass reinforced plastic components and two air filters. Several uncertainties arose in the finite element (FE) model due to the HDAC’s component material properties and assembly conditions. To help understand and mitigate these uncertainties, analytical and experimental modal models were created concurrently to perform a model correlation and calibration. Over the course of the project simple and practical methods were …

Rapid Space Trajectory Generation Using A Fourier Series Shape-Based Approach, Ehsan Taheri

Dissertations, Master's Theses and Master's Reports - Open

With the insatiable curiosity of human beings to explore the universe and our solar system, it is essential to benefit from larger propulsion capabilities to execute efficient transfers and carry more scientific equipment. In the field of space trajectory optimization the fundamental advances in using low-thrust propulsion and exploiting the multi-body dynamics has played pivotal role in designing efficient space mission trajectories. The former provides larger cumulative momentum change in comparison with the conventional chemical propulsion whereas the latter results in almost ballistic trajectories with negligible amount of propellant. However, the problem of space trajectory design translates into an optimal …

Water Access And Maintenance In Karonga, Malawi, Donald A. Norris

Dissertations, Master's Theses and Master's Reports - Open

This report is a case study of how Mwangalala community accesses water and how that access is maintained. Mwangalala community is located in the northern tip of Karonga district in Malawi, Africa. The case study evaluates how close the community is to meeting target 10 of the Millennium Development Goals, sustainable access to safe drinking water, and evaluates the current water system through Human Centered Design’s criteria of desirability, feasibility, and viability. It also makes recommendations to improve water security in Mwangalala community.

Data was collected through two years of immersive observation, interviews with 30 families, and observing two wells …

A Study Of Acoustic Boom Generation Due To Vibro-Acoustic Coupling In Passenger Cars, Mayuresh Pathak

Dissertations, Master's Theses and Master's Reports - Open

This thesis aims at understanding the vibro-acoustic behavior related to vehicle boom in passenger cars. Acoustic boom in the 40 Hz frequency range is studied on a 2013 Chevrolet Cruze LTZ model. Impact testing, full vehicle structural and acoustic modal tests are first performed to understand, locate and test the boom phenomenon and the fluid-structure interaction between the vehicle structure and acoustic cavity. Later, different iterations like effect of door cavities, trunk cavity and rear seats are also tested to understand their participation. LMS Test.Lab software is used for data acquisition, processing and analysis of the test results.

Finite Element …

Military Vehicle Optimization And Control, Denise M. Rizzo

Dissertations, Master's Theses and Master's Reports - Open

It is remarkable that there are no deployed military hybrid vehicles since battlefield fuel is approximately 100 times the cost of civilian fuel. In the commercial marketplace, where fuel prices are much lower, electric hybrid vehicles have become increasingly common due to their increased fuel efficiency and the associated operating cost benefit. An absence of military hybrid vehicles is not due to a lack of investment in research and development, but rather because applying hybrid vehicle architectures to a military application has unique challenges. These challenges include inconsistent duty cycles for propulsion requirements and the absence of methods to look …

A Backing Device Based On An Embedded Stiffener And Retractable Insertion Tool For Thin-Film Cochlear Arrays, Radheshyam Tewari

Dissertations, Master's Theses and Master's Reports - Open

Intracochlear trauma from surgical insertion of bulky electrode arrays and inadequate pitch perception are areas of concern with current hand-assembled commercial cochlear implants. Parylene thin-film arrays with higher electrode densities and lower profiles are a potential solution, but lack rigidity and hence depend on manually fabricated permanently attached polyethylene terephthalate (PET) tubing based bulky backing devices. As a solution, we investigated a new backing device with two sub-systems. The first sub-system is a thin poly(lactic acid) (PLA) stiffener that will be embedded in the parylene array. The second sub-system is an attaching and detaching mechanism, utilizing a poly(N-vinylpyrrolidone)-block-poly(d,l-lactide) (PVP-b-PDLLA) copolymer-based …

Understanding Chassis Inputs From The Rear Suspension Of A Snowmobile, Jamie L. Kleinendorst

Dissertations, Master's Theses and Master's Reports - Open

Today’s snowmobile industry faces great challenges in the field of noise & vibration. The area of main concern is the pass-by noise restriction defined by the Society of Automotive Engineers (SAE) test standard J192, with a maximum sound pressure level of 78 dB(A) being required by many states and national parks. To continue meet or beat this requirement without effecting machine performance, a deeper understanding of the sound transfer paths is required. This thesis examines the transfer paths created by the tunnel, rear suspension, drive shaft, and rubber composite track, with the primary source being suspension input through the ground. …

Water Transport Through Porous Media And In Flow Channels Of Proton Exchange Membrane Fuel Cell, Mehdi Mortazavi

Dissertations, Master's Theses and Master's Reports - Open

Proton exchange membrane (PEM) fuel cell has been known as a promising power source for different applications such as automotive, residential and stationary. During the operation of a PEM fuel cell, hydrogen is oxidized in anode and oxygen is reduced in the cathode to produce the intended power. Water and heat are inevitable byproducts of these reactions. The water produced in the cathode should be properly removed from inside the cell. Otherwise, it may block the path of reactants passing through the gas channels and/or gas diffusion layer (GDL). This deteriorates the performance of the cell and eventually can cease …

Modeling Of Transfer Path For Determination Of Combustion And Noise Metrics On Diesel Engines, Libin Jia

Dissertations, Master's Theses and Master's Reports - Open

Determination of combustion metrics for a diesel engine has the potential of providing feedback for closed-loop combustion phasing control to meet current and upcoming emission and fuel consumption regulations. This thesis focused on the estimation of combustion metrics including start of combustion (SOC), crank angle location of 50% cumulative heat release (CA50), peak pressure crank angle location (PPCL), and peak pressure amplitude (PPA), peak apparent heat release rate crank angle location (PACL), mean absolute pressure error (MAPE), and peak apparent heat release rate amplitude (PAA). In-cylinder pressure has been used in the laboratory as the primary mechanism for characterization of …

Model Updating And Structural Health Monitoring Of Horizontal Axis Wind Turbines Via Advanced Spinning Finite Elements And Stochastic Subspace Identification Methods, Antonio Velazquez Hernandez

Dissertations, Master's Theses and Master's Reports - Open

Wind energy has been one of the most growing sectors of the nation’s renewable energy portfolio for the past decade, and the same tendency is being projected for the upcoming years given the aggressive governmental policies for the reduction of fossil fuel dependency. Great technological expectation and outstanding commercial penetration has shown the so called Horizontal Axis Wind Turbines (HAWT) technologies. Given its great acceptance, size evolution of wind turbines over time has increased exponentially. However, safety and economical concerns have emerged as a result of the newly design tendencies for massive scale wind turbine structures presenting high slenderness ratios …