Mechanical Engineering Commons^™

Influence Of Micro-Nucleate Boiling On Annular Flow Regime Heat Transfer Coefficient Values And Flow Parameters – For High Heat-Flux Flow Boiling Of Water, Soroush Sepahyar

Dissertations, Master's Theses and Master's Reports

Analysis of results from steady and steady-in-the-mean high heat-flux (15 - 70 W/cm², with water as working fluid) shear driven annular flow-boiling experiments presented here - and low heat-flux (0.1- 1 W/cm², with FC-72 as working fluid) experiments presented elsewhere – together lead to a key conclusion. The conclusion is that heat carrying nucleation rates go often undetected by the typically used visualization approaches for flow boiling – as such flows often involve µm- to sub- µm scale bubble diameters in millimeter-scale ducts. These nucleation rates play a significant role in most of the so-called convective …

Experimental Characterization Of Hydraulic System Sound, Ben Kolb

Dissertations, Master's Theses and Master's Reports

The purpose of this research was to establish test methods for characterizing the interaction between the hydraulic fluid and hydraulic hose at clipping points in mobile heavy equipment hydraulic systems. A simple hydraulic circuit test bench was developed and the laboratory axial piston pump was characterized using ISO 10767-1. A direct relationship between the fluidborne noise and structureborne noise present at each hose clip location was observed for a specific operating condition using operating deflection shapes and structureborne noise measurements. This result shows that optimal hose clip placement can be a viable solution to structureborne noise reduction. Additionally, a modal …

Multi-Scale, Capillary Assisted Copper Surfaces For Enhanced Pool Boiling Heat Transfer Processes, Chetan Agarwal

Dissertations, Master's Theses and Master's Reports

Phase-change heat transfer through pool boiling process offers a promising thermal management solution in applications wherein conventional air or single-phase liquid-based cooling methods prove inefficient such as for high-power electronics. Pool boiling process, which utilizes the latent heat of evaporation, provides a robust and efficient way to efficiently dissipate the excessive heat generated in a small footprint area in particular as seen in CPUs (Central Processing Units), GPUs (Graphics Processing Units), LEDs (Light Emitting Diodes), radars, and other demanding computing, sensing and surveillance electronics. Although boiling process has been studied for over five decades, it has not been yet adapted …

Estimation And Prediction Of The Human Gait Dynamics For The Control Of An Ankle-Foot Prosthesis, Guilherme Aramizo Ribeiro

Dissertations, Master's Theses and Master's Reports

With the growing population of amputees, powered prostheses can be a solution to improve the quality of life for many people. Powered ankle-foot prostheses can be made to behave similar to the lost limb via controllers that emulate the mechanical impedance of the human ankle. Therefore, the understanding of human ankle dynamics is of major significance. First, this work reports the modulation of the mechanical impedance via two mechanisms: the co-contraction of the calf muscles and a change of mean ankle torque and angle. Then, the mechanical impedance of the ankle was determined, for the first time, as a multivariable …

Using Frequency Based Substructuring To Optimize Multi-Axis Resonant Plate Shock Tests, Erica M. Jacobson

Dissertations, Master's Theses and Master's Reports

Resonant plate pyroshock tests only offer to test one component axis at a time, while the qualification pyroshock tests often have three single-axis specifications to meet. There is an interest in creating a multi-axis test environment from the single-axis resonant plate parts to save testing time, create a more realistic test environment, and monitor the possibility of an overtest. To investigate this, LaGrange-multiplier frequency based substructuring was implemented to virtually arrange the single-axis resonant plate subsystems into different assembly configurations and mathematically calculate the new assembly dynamics. A shock response spectrum was calculated from the new assembly dynamics through an …

Development Of A Fused Deposition 3d Printed Buoy And Method For Quantifying Wave Tank Reflections, Samantha G. Swartzmiller

Dissertations, Master's Theses and Master's Reports

Testing model scale prototypes is integral to the development of wave energy converter (WEC) technology. Model scale WECs are tested in wave tanks where they are subjected to repeatable wave fields. Their presence in water creates radiated waves that eventually reflect off tank walls disrupting the intended wave field. Fabrication of model scale WECs is another developing aspect of tank testing. Often model WECs are built of foam. Additive manufacturing is a promising alternative although the most common method, fused deposition modeling (FDM) 3D printing, does not typically produce waterproof parts. The goals of this work were 1) develop a …

High Injection Pressure Dme Ignition And Combustion Processes: Experiment And Simulation, Xiucheng Zhu

Dissertations, Master's Theses and Master's Reports

With nearly smokeless combustion, Dimethyl Ether (DME) can be pressurized and used as a liquid fuel for compression-ignition (CI) combustion. However, due to its lower heating value and liquid density compared with diesel fuel, DME has a smaller energy content per unit volume. To obtain an equivalent energy content of diesel, approximately 1.86 times more quantity of DME is required. This can be addressed by a larger nozzle size or higher injection pressure. However, the effect of high injection pressure on DME spray combustion characteristics have not yet been well understood. In order to fill this gap, spray and combustion …

Optimization And Control Of Arrays Of Wave Energy Converters, Jianyang Lyu

Dissertations, Master's Theses and Master's Reports

Wave Energy Converter Array is a practical approach to harvest ocean wave energy. To leverage the potential of the WEC array in terms of energy extraction, it is essential to have a properly designed array configuration and control system. This thesis explores the optimal configuration of Wave Energy Converters (WECs) arrays and their optimal control. The optimization of the WEC array allows both dimensions of individual WECs as well as the array layout to varying. In the first optimization problem, cylindrical buoys are assumed in the array where their radii and drafts are optimization parameters. Genetic Algorithms are used for …

Paddle Mixer-Extrusion Reactor For Torrefaction And Pyrolysis, Stas Zinchik

Dissertations, Master's Theses and Master's Reports

This work is focused on the fundamental understanding and the development of paddle mixer reactors (or modified screw augers). This work will contribute to the effort of the thermal conversion of biomass and wastes. We developed and studied two paddle systems (i) 25-mm lab-scale (up to 1 kg/hr) and (ii) 101-mm pilot-scale (up to 100 kg/hr). Thermal behavior of the two systems was studied and it was estimated that the lab-scale system has a high heating rate of up to 530 °C/s. Residence times were thoroughly measured and were determined as a function of rotation frequency and volume fraction. We …

Design And Development Of Personal Protective Equipment Products To Reduce The Impacts Of Machete Injuries For Indigenous Ngäbe Subsistence Farmers In Bocas Del Toro, Panama, Micah Koller

Dissertations, Master's Theses and Master's Reports

Design and development of personal protective equipment products for workers using machetes (MPPE) is considered in the specific context of indigenous Ngäbe subsistence farmers in a small, rural community in Bocas del Toro, Panama where the author spent two years as a Peace Corps volunteer from 2017-2019. People in this community regularly suffer significant health and economic impacts due to accidents with machetes, which are essential tools in their farm work and daily lives. The history, criticisms, and recent frameworks related to product design and development in resource-poor markets is examined, and specific details of the problem of machete injuries …

Mpc-Based Autonomous Driving Control With Localized Path Planning For Obstacle Avoidance And Navigating Signalized Intersections, Sai Rajeev Devaragudi

Dissertations, Master's Theses and Master's Reports

Connected and autonomous vehicles are becoming the major focus of research for the industry and academia in the automotive field. Many companies and research groups have demonstrated the advantages and the requirement of such technology to improve the energy efficiency of vehicles, decrease the number of crash and road accidents, and control emissions.

This research delves into improving the autonomy of self-driving vehicles by implementing localized path planning algorithms to introduce motion control for obstacle avoidance during uncertainties. Lateral path planning is implemented using the A* algorithm combined with piecewise Bezier curve generation which provides an optimum trajectory reference to …

Improved Low-Frequency Impact Insulation Class Measurements Based On Comparison Techniques, Sunit Girdhar

Dissertations, Master's Theses and Master's Reports

In today’s world, noise pollution is growing as a major concern and it is becoming more and more difficult to find quiet places. But when the problem escalates to the extent that people are annoyed with loud noises even in their apartments, it becomes an alarming issue for engineers. Around the world, cities have defined some basic performance requirements for buildings, and isolation of residents from noise is one of the cardinal performance requirements. In the United States, building codes use the Impact Insulation Class (IIC) rating to characterize the performance of floor/ceiling assemblies. This method uses the response measured …

Comparative Study And Design Of Economical Sound Intensity Probe, Karan Gundre

Dissertations, Master's Theses and Master's Reports

The theory of sound intensity measurement using the two-microphone method was first developed in the late 1970s. Even though the measurements were limited by the technology of the time, the theory was straight-forward and considerable attention was given to improving precision during testing or post-processing. With the development of modern equipment, however, the focus shifted to the apparatus. The commercial intensity probes available today have microphones that are already phase-matched. This eliminates the need for correction during or post-testing as a majority of the errors are minimized before any data is even collected. Although such intensity probes facilitate taking precise …

Remotely Controlled Industrial Robotic Arm And Simulation Of Automated Thermal Furnace, Prince Mehandi Ratta

Dissertations, Master's Theses and Master's Reports

The right execution of controllers ensures the correct analysis of information, generating efficient results and better optimizing the system. In this report, two controllers were designed. Firstly, a remotely controlled robotic arm, since there are no such type commercially available controllers. Moreover, robotic platforms are costly, so students and researchers are often unable to learn the concepts of programming industrial robots. This project makes a non-destructive, remotely-controlled robotic arm to better teach students and researchers about programming and control of robotic arms. Secondly, simulation of an automated thermal furnace for ArcelorMittal on SIMULINK, which is used for the annealing process …

Towards Sustainable Production Of Chemicals And Fuels From The Fast Pyrolysis Of Waste Polyolefin Plastics, Ulises Gracida Alvarez

Dissertations, Master's Theses and Master's Reports

The increasing amount of plastic waste (PW) generation has become an important concern due to the leveled-off recycling rates. Therefore, governmental agencies around the world, including state governments in the United States, have proposed initiatives to minimize the amount of PW that is landfilled and encourage recycling or energy recovery. Circular economy is a strategy that attempts on reusing PW to produce new polymers while avoiding its disposal and the use of virgin material. Chemical recycling raises an interesting technology prospect due to the potential reduction of pollutant emissions and the establishment of a circular economy through the production of …

Modeling And Control Of Maximum Pressure Rise Rate In Rcci Engines, Aditya Basina

Dissertations, Master's Theses and Master's Reports

Low Temperature Combustion (LTC) is a combustion strategy that burns fuel at lower temperatures and leaner mixtures in order to achieve high efficiency and near zero NOx emissions. Since the combustion happens at lower temperatures it inhibits the formation of NOx and soot emissions. One such strategy is Reactivity Controlled Compression Ignition (RCCI). One characteristic of RCCI combustion and LTC com- bustion in general is short burn durations which leads to high Pressure Rise Rates (PRR). This limits the operation of these engines to lower loads as at high loads, the Maximum Pressure Rise Rate (MPRR) hinders the use of …

Modeling Of Thermal Dynamics In Chevrolet Volt Gen Ii Hybrid Electric Vehicle For Integrated Powertrain And Hvac Optimal Operation Through Connectivity, Nehal Doshi

Dissertations, Master's Theses and Master's Reports

Integrated thermal energy management across system level components in electric vehicles (EVs) and hybrid electric vehicles (HEVs) is currently an under explored space. The proliferation of connected vehicles and accompanying infrastructure in recent years provides additional motivation to explore opportunities in optimizing thermal energy management in EVs and HEVs with the help of this newly available connected vehicle data. This thesis aims to examine and analyze the potential to mitigate vehicle energy consumption and extend usable driving range through optimal control strategies which exploit physical system dynamics via controls integration of vehicle subsystems.

In this study, data-driven and physics-based models …

Estimation Of Multi-Directional Ankle Impedance As A Function Of Lower Extremity Muscle Activation, Lauren Knop

Dissertations, Master's Theses and Master's Reports

The purpose of this research is to investigate the relationship between the mechanical impedance of the human ankle and the corresponding lower extremity muscle activity. Three experimental studies were performed to measure the ankle impedance about multiple degrees of freedom (DOF), while the ankle was subjected to different loading conditions and different levels of muscle activity. The first study determined the non-loaded ankle impedance in the sagittal, frontal, and transverse anatomical planes while the ankle was suspended above the ground. The subjects actively co-contracted their agonist and antagonistic muscles to various levels, measured using electromyography (EMG). An Artificial Neural Network …

Networked Microgrid Optimization And Energy Management, Robert S. Jane

Dissertations, Master's Theses and Master's Reports

Military vehicles possess attributes consistent with a microgrid, containing electrical energy generation, storage, government furnished equipment (GFE), and the ability to share these capabilities via interconnection. Many military vehicles have significant energy storage capacity to satisfy silent watch requirements, making them particularly well-suited to share their energy storage capabilities with stationary microgrids for more efficient energy management. Further, the energy generation capacity and the fuel consumption rate of the vehicles are comparable to standard diesel generators, for certain scenarios, the use of the vehicles could result in more efficient operation. Energy management of a microgrid is an open area of …

Acoustic Localization Techniques For Application In Near-Shore Arctic Environments, Miles B. Penhale

Dissertations, Master's Theses and Master's Reports

The Arctic environment has undergone significant change in recent years. Multi-year ice is no longer prevalent in the Arctic. Instead, Arctic ice melts during summer months and re-freezes each winter. First-year ice, in comparison to multi-year ice, is different in terms of its acoustic properties. Therefore, acoustic propagation models of the Arctic may no longer be valid. The open water in the Arctic for longer time periods during the year invites anthropogenic traffic such as civilian tourism, industrial shipping, natural resource exploration, and military exercises. It is important to understand sound propagation in the first-year ice environment, especially in near-shore …

Online Learning Of The Spatial-Temporal Channel Variation In Underwater Acoustic Communication Networks, Wensheng Sun

Dissertations, Master's Theses and Master's Reports

Influenced by environmental conditions, underwater acoustic (UWA) communication channels exhibit spatial and temporal variations, posing significant challenges for UWA networking and applications. This dissertation develops statistical signal processing approaches to model and predict variations of the channel and relevant environmental factors. Firstly, extensive field experiments are conducted in the Great Lakes region. Three types of the freshwater river/lake acoustic channels are characterized in the aspects of statistical channel variations and sound propagation loss, including stationary, mobile and under-ice acoustic channels. Statistical data analysis shows that relative to oceanic channels, freshwater river/lake channels have larger temporal coherence, higher correlation among densely …

3d Printing In Low Resource Healthcare Settings: Analysis Of Potential Implementations, Alenna Beroza

Dissertations, Master's Theses and Master's Reports

3D printing has gained significant momentum in the past ten years, and its unique advantages make it especially ideal for use in low resource healthcare settings, where many designs have already been successfully implemented. Yet, little has been studied on how 3D printing can be sustainably and functionally implemented in low resource healthcare systems as a manufacturing practice. In this report, three business models are proposed for this implementation: In-House Operator, Independent Operator, and Print Farm. These models were then tested over four months in Kisumu county, Kenya, at two workshops and seven public hospitals. I worked with local medical …

Crack Pattern Simulation Of Pressurized Borosilicate Glass Tube Under Pellet Impact Using Ale Method, Omkar Bhumkar

Dissertations, Master's Theses and Master's Reports

Transformer bushings are a common target for sniper attacks to cause power failure in large areas. Given the size, internal pressure and brittle nature of transformer bushing, pellet impact causes damage to surrounding components due to broken bushing pieces. To mitigate this, a project was initiated by United States Burau of Reclaimation to develop a safety mechanism. Finite Element Analysis is proposed to optimize and reduce cost of the design.

A simplified Finite Element model is created which consists of 0.22 caliber lead pellet impacting Pyrex 7740 borosilicate glass tube. Previous studies on the effect of the mesh pattern, size …

Pyrolysis Of Fiber-Plastic Waste Blends, Shreyas Kolapkar

Dissertations, Master's Theses and Master's Reports

The main objective of this work is to investigate fast pyrolysis of fiber and plastic feedstocks in order to understand the synergistic effect from their co-pyrolysis. In this on-going work, fiber, plastic and their blend are characterized and pyrolysis oil is produced from them in the fast batch pyrolysis reactor. Based on a heat transfer model it is shown that results of oil produced from batch reactor will be applicable to the continuous paddle reactor. From feedstock characterization, chlorine was observed particularly in the plastic feedstock. Thus, chlorine removal method using torrefaction and high shear mixing was implemented and was …

Extending Maneuverability Of Internally Actuated Underwater Gliders, An Attempt To Develop An Open Platform For Research And Education, Saeedeh Ziaeefard

Dissertations, Master's Theses and Master's Reports

Increasing maneuverability of internally actuated Underwater Gliders (UGs) is inevitable due to high demands in underwater surveillance and reconnaissance missions where agility and stealthiness are the keys to success. High maneuverability is needed to provide the opportunity for optimal trajectory planning, planar motion smoothness, and re-planning adapting to the dynamic environments.

This work explores extending the maneuverability of underwater gliders through coupled improvement in mechanical design, efficient use of internal actuation, and motion planning strategy utilizing flight concatenation. The existence of five flight patterns ``advanced flight", inspired by air gliders, enabled solely by utilizing internal actuation are investigated: Circle, Oval …

Modelling And Analysis Of Chevy Volt Gen Ii Hybrid Vehicle In Electric Mode, Kaushik Surresh

Dissertations, Master's Theses and Master's Reports

The technical report discusses the high fidelity modelling of the powertrain of Chevy Volt Gen II Hybrid Vehicle in the Electric Mode. The overall objective of the powertrain model was to predict total energy consumed within 5% of experimental data for different drive cycles in Charge Depleting Mode. The following powertrain elements were modelled in Matlab and Simulink using parameters and performance maps provided by General Motors: battery, E-Motor, TPIM power electronics, transmission auxiliary pumps and spin losses.

An electric circuit based dynamic model of the Li-ion battery was developed. Static models of the E Motor, TPIM inverter, transmission auxiliary …

Capillary-Assisted Enhanced Condensation Heat Transfer For Low Surface Tension Liquids, Gnana Vishnu Durgam

Dissertations, Master's Theses and Master's Reports

Extensive research has been carried out over the course of the last few decades to induce dropwise condensation as it offers 5 - 7 times better heat transfer performance compared to filmwise condensation process. A number of methods such as low surface energy hydrophobic coatings, surface modification of hydrophobic surfaces to fabricate micro, nano and hierarchical structures, and the recent incorporation of jumping droplet phenomenon have provided effective means to further enhance the condensation heat transfer. However, existing methods to enhance condensation heat transfer rate fail in the case of low surface tension, highly wetting liquids such as hydrocarbons, cryogens, …

Meniscus Modeling And Emission Studies Of An Ionic Liquid Ferrofluid Electrospray Source Emitting From A Magneto-Electric Instability, Brandon Jackson

Dissertations, Master's Theses and Master's Reports

This dissertation presents three studies on the electrospray of ionic liquid ferrofluid. Ionic liquid ferrofluids are electrically conductive super-paramagnetic fluids which respond strongly in the presence of electric and magnetic fields. When a small reservoir of ionic liquid ferrofluid is positioned within a magnetic field, magnetic stresses will deform the fluid interface into a peak. The addition of a strong electric field will further stress the fluid interface until a threshold stress is reached at which point the surface tension cannot contain the combined stresses and a spray of fluid or ions results at the apex. This process is termed …

Investigation On The Potential Of A Co2 Capture System, Downstream Of The Aftertreatment System For A Heavy-Duty Engine Application, Murchana Pathak

Dissertations, Master's Theses and Master's Reports

The transportation sector accounts for the second largest source of CO₂ emissions after power generation. New Corporate Average Fuel Economy (CAFE) regulations are focusing on improving energy through reduced fuel consumption and greenhouse gas emissions. This work investigates the potential of a CO₂ capture system downstream of an aftertreatment system for a heavy-duty engine application. Amine absorption has been described as one of the most effective ways to capture CO₂ from the exhaust for point sources. Therefore, using thermal-swing absorption process with potassium carbonate (K₂CO₃) as the absorbent liquid, a process was analyzed …

The Interaction Of Ignition And In-Cylinder Flow On Flame Kernel Development And Its Impacts On Combustion In An Optically Accessible Direct Injection Engine, Yanyu Wang

Dissertations, Master's Theses and Master's Reports

A significant challenge facing spark-ignited (SI) engines to achieve higher efficiency via highly diluted combustion is the quickly increased combustion instability as the dilution level increases. The flow motion variation has been identified as a dominant factor that introduces combustion variability at highly diluted conditions. However, the detailed mechanism of how the variation in flow motion impacts the flame kernel development and introduces combustion instability is only partially understood. This research investigated the impacts of the in-cylinder flow on variability of the ignition and early flame kernel development in a single cylinder direct-injection spark-ignition (DI-SI) optically accessible engine and accessory …