Mechanical Engineering Commons^™

A Computational Investigation Of Wood Selection For Acoustic Guitar, Jonah Osterhus

Senior Honors Theses

The acoustic guitar is a stringed instrument, often made of wood, that transduces vibrational energy of steel strings into coupled vibrations of the wood and acoustic pressure waves in the air. Variations in wood selection and instrument geometry have been shown to affect the timbre of the acoustic guitar. Computational methods were utilized to investigate the impact of material properties on acoustic performance. Sitka spruce was deemed the most suitable wood for guitar soundboards due to its acoustic characteristics, strength, and uniform aesthetic. Mahogany was deemed to be the best wood for the back and sides of the guitar body …

Dynamic Impact Testing And Numerical Analysis Of Non-Proprietary Astm F2656-20 M50 Anti-Ram Barrier Components, Weston Kelley

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

In a post-9/11 world, hostile actors are using vehicles as weapons to inflict civilian casualties. Pedestrians, vulnerable road users, military personnel, and police may be targeted using a vehicle as a weapon. The United States Department of Defense (DoD) also utilizes Entry Control Facilities (ECFs) which are carefully designed transportation corridors to manage how threat vehicles are able to access military facilities. In 2004, DoD started to upgrade all ECFs using both passive and active barriers. Many anti-ram vehicle barriers were evaluated according to the criteria established in ASTM F2656, but to date few options are available which are (1) …

Towing Tank Trials Of Hydrokinetic Turbine Scale Model To Support Marine Energy System Verification, Shahab Rouhi

University of New Orleans Theses and Dissertations

In response to the escalating demand for sustainable energy solutions and the critical reevaluation of conventional fossil fuels due to environmental concerns, this dissertation embarks on a comprehensive exploration of hydrokinetic energy as a promising alternative. The study delves into the underexplored domain of hydrokinetic energy, leveraging innovative methodologies for effective utilization and harnessing, particularly through the development and investigation of hydrokinetic turbines.

In the realm of hydrokinetic energy conversion, our research has exclusively concentrated on horizontal-axis turbines, distinct from other turbine configurations. Noteworthy is the adaptation of a conventional horizontal-axis wind turbine for water currents, revealing enhanced performance through …

Understanding The Impact Of Divertor And Main Chamber Ion Fluxes On Divertor Closure In The Diii-D Tokamak, Kirtan M. Davda

Doctoral Dissertations

The diverted tokamak redirects extreme heat and particles to targets, a plasma-facing component designed for such loads. Here, the local fluxes produce strong particle recycling and sputtering. Recycled neutrals can “leak” into the region between the core and wall, the scrape-off-layer (SOL), impacting plasma performance. Increasing divertor closure can reduce leakage by containing neutrals within the divertor. However, there exists a need to quantify divertor baffle restrictions and understand closure directly from empirical data as opposed to indirectly through modeling.

Our study introduces the Geometric Restriction Parameter (GRP) based on simplifying neutral transport to ballistic pathways. Specifically, it considers the …

Tunable Catalysts And Electrodes With High Material Utilization And Durability For Hydrogen Production, Lei Ding

Doctoral Dissertations

Hydrogen, the future energy carrier, has gained extensive attention due to its advantages of high energy density, low weight, and zero-carbon emission. So far, hydrogen has been widely used in various fields including transportation, oil upgrading, metal refining, etc. Most hydrogen is currently produced from fossil fuels, which can cause serious environmental problems. Water electrolysis was proposed to produce clean hydrogen with carbon-free emission and only byproduct of oxygen. Among various water electrolyzer devices, the proton exchange membrane electrolyzer cell (PEMEC) shows great potential to produce green hydrogen by integrating renewable sources (solar, wind, etc.) due to its advantages of …

Thermal Runaway Of Li-Ion Batteries: Triggering, Emission, And Mitigation, Liwen Zhang

Doctoral Dissertations

In the contemporary landscape, lithium-ion batteries (LIBs) are key components powering a wide array of electronic devices and electric vehicles (EVs). As society increasingly relies on these batteries for their efficiency and functionality, understanding and mitigating potential risks, such as thermal runaway (TR) events, become imperative. The objective of this dissertation is to comprehensively understand TR characteristics of LIBs through a combination of experiments and numerical simulation, thereby enhancing battery safety, refining design standards, and providing insights and guidelines for the prevention and management of TR events.

Firstly, this dissertation explores the safety regime of LIBs TR through a computational …

Renewable Energy Misinformation: A Literature Based Approach To Rebutting False Claims, Matthew Ard

McNair Research Journal SJSU

No abstract provided.

Radiative Cooling For Energy-Efficient Power Generation, Rickia Hanna

Celebrating Scholarship and Creativity Day (2018-)

This thesis examined radiative cooling on a small scale using a hybrid photovoltaic/radiative cooling model system, to determine its efficiency for large-scale power generation. Radiative cooling is concerned with heat transfer and this thesis’s main goal is to harness that heat energy to produce electricity. The efficiency of the system was tested using various light sources at different angles and total power output. The testing was done several times and there proved to be a proportional relationship between light intensity and current output. However, due to the performance threshold of the PTEC module, the component of the system used to …

Benchmarking Of A Sco2 Heat Exchanger Flow Loop, David Velasco

Doctoral Dissertations and Master's Theses

Heat transfer of supercritical carbon dioxide (sCO2) was studied experimentally by commissioning a sCO2 flow loop featuring a horizontal tube-in-tube counterflow heat exchanger with a circular cross section. The main objective was to establish experimental heat transfer research capabilities for sCO2 at Embry-Riddle Aeronautical University’s (ERAU) Thermal Science Lab. sCO2 experiences a drastic change in thermophysical properties near its critical point that results in unique heat transfer characteristics. The high pressures at which sCO2 exists make the large gradients in thermophysical and transport properties difficult to study, experimentally and numerically. However, understanding the heat transfer characteristics and thermophysical behavior of …

Performance Augmentation Of Single-Slope Solar Distiller Using An Evacuated Tube Solar Collector: Theoretical Study, Eman Mohammed Abuelezz Eng., Yasser El-Samadony Prof., Khaled Khodary Esmaeil Assoc. Prof., Mohamed Elsheshtawy Zayed Dr.

Journal of Engineering Research

In this research, the performance analysis of a solar-powered desalination system incorporating a single slope-slope solar still and an evacuated tube solar collector is theoretically investigated. The system comprises a solar evacuated tube that absorbs solar radiation, transferring heat to saline water. This water then flows into a solar still, where it absorbs solar energy, boosting the evaporation rate. Two solar distillers, namely the conventional solar distiller (Still-I) and solar still integrated with evacuated tube solar collector (Still-II), are simulated and analyzed under identical outdoor conditions in Tanta, Egypt. A comprehensive theoretical model, developed using FORTAN programming, simulates the performance …

Numerical Analysis Of Flow Fields For The Different Models Of The Shrouded Savonius Rotor, Alsaied Khalil Mahmoud, Mohamed Mahgoub Bassuoni, Mohamed Fawzy Obiaa, Ahmed Mostafa Khaira

Journal of Engineering Research

In this study, the effect of three different lengths (short, medium, and long) of flanged shrouded Savonius wind turbines is investigated three-dimensional (3-D) numerically by ANSYS-FLUENT. The 3-D numerical model of a simple rotor is validated by comparing the results with previous published experimental ones at the same operating conditions and geometry. The numerical and experimental results indicate a good agreement with each other when using the SST K-ω model with a time step size of 0.0025 s.The analysis of the numerical results of the three flanged shrouded models shows an enhancement of the torque coefficient at tip speed ratio …

Quantum-Powered Battery Scheduling In Modern Distribution Grids, Diba Ehsani

Electronic Theses and Dissertations

The rising need for exploiting a novel and evolved computation is an increasing concern in the power distribution system to address the exponential growth of distribution-connected devices. Scheduling numerous battery energy storage systems in an optimal way is one of the emerging challenges that will be more noticeable as the number of batteries, including residential, community, and vehicle batteries, increases in the grid. This thesis focuses on this topic and offers a necessary component in building the quantum-compatible distribution system of the future. Using a constrained quadratic model (CQM) on D-Wave’s hybrid solver as well as a binary quadratic model …

Modeling Thermosyphon And Heat Pipe Performance For Mold Cooling Applications, Dwaipayan Sarkar

Electronic Thesis and Dissertation Repository

Thermosyphons are enhanced heat transfer devices that can continuously transfer very large amounts of heat rapidly over long distances with small temperature differences. The high heat transfer rate is achieved through simultaneous boiling and condensation of the working fluid and the continuous heat transfer is achieved through recirculation of the working fluid in its liquid and vapor phase. A potentially important application of the thermosyphons has been towards reducing the cycle times of the mold cooling processes which would provide economic incentives to the automotive industry.

Different operational and geometrical parameters such as the input heating power, fill ratio (FR), …

Enhancing The Performance Of Conventional Solar Still Using The Nano-Doped Paint (Ndp) Coating, Hagar Alm-Eldin Bastawissi Prof.Dr, Nermin Elgendy Engineer, Ayman R. El-Tohamy

Journal of Engineering Research

Nations are throughout the entire globe continuously confronting the problem of potable water shortage. Recently, it has been thought that using solar energy to desalinate brackish water offers a practical answer to the world's water crises. The output of these stills, is meager, and academics haven't done much to boost it in any way. Solar distillers have been proposed as an efficient method to produce potable water. In recent years, saltwater has produced drinking water by various ways. The efficiency of a solar distiller is significantly influenced by various factors, most important factor of them is the absorber surface. In …

Numerical Study Of The Effect Of Long Shroud Diffuser With And Without Plate Obstacle On The Performance Of Savonius Wind Turbine, Alsaied Khalil Mahmoud, Mohamed Mahgoub Bassuoni, Mohamed Fawzy Obiaa, Ahmed Mostafa Khaira

Journal of Engineering Research

This study presents the three-dimensional (3-D) numerical analysis of the influence of the plate obstacle installed at the entrance of the long flanged diffuser on the simple Savonius rotor performance by ANSYS 2022 R1. In the beginning, the 3-D numerical model is validated using the sst k-ω turbulence model with the previous published experimental results at the same conditions, and they are in good agreement with each other. The numerical results indicate the remarkable enhancement of the rotor performance at a tip speed ratio of 0 to 0.7 by using a flanged diffuser with a plate obstacle. The shrouded diffuser …

Schaeffler Icvd Coating Machine, Louis Mcgrath

Williams Honors College, Honors Research Projects

Chemical Vapor Deposition (CVD) is mutual technology used to deposit thin film through a gaseous phase by vaporizing the solid materials. This conventional process usually requires high thermal stability of the materials, which is not applicable for most of the polymeric materials. Therefore, a novel process, initiated Chemical Vapor Deposition (iCVD) is developed by introducing the gaseous monument and initiator to form the thin film in-situ. By adjusting the free-radical polymerization in the vapor phase, a variety of thin and uniform polymer films can be achieved. Depending on the chemistry, iCVD has many categories. This report explains the design …

Development Of A Modular Solar Shingle, David Dye, Andrew Schmidt, Mitchell Cozzens

Williams Honors College, Honors Research Projects

The goal of this research project is to design, prototype, and test an array of solar roofing shingles using print-in-place principles using an automated circuitry printer and 3D printed components. The shingle shall emphasize ease of installation, maintenance, and affordability in contrast to the current market for solar roofing. The design goal is to develop a manufacturing process to be more cost and time effective than current manufacturing techniques. The prototype will consist of a roof with this system, demonstrating the durability, assembly, and ease of installation. Finally, material/design suitability will be implemented in conjunction with postprocessing techniques to create …

Graphene Reinforced Polymer Composite For Small-Scale Vertical Axis Wind Turbine Rotors, Kunal A. Bachim

Mechanical and Aerospace Engineering Theses

Polymers have evolved as an indispensable asset in various sectors ranging from packaging and construction to energy and aerospace. However, the accumulation of polymer waste poses a necessity to shift toward sustainable waste management processes. Mechanical recycling is a primary method in establishing a circular economy approach for polymers. However, a fundamental challenge arises in this process: a decrease in the mechanical performance of the recycled product compared to that of its pristine counterpart.

This project addresses the challenge of enhancing the recyclability of polyethylene terephthalate (PET) from discarded polymer material by incorporating graphene nanoparticles into the polymer matrix during …

Data Driven And Machine Learning Based Modeling And Predictive Control Of Combustion At Reactivity Controlled Compression Ignition Engines, Behrouz Khoshbakht Irdmousa

Dissertations, Master's Theses and Master's Reports

Reactivity Controlled Compression Ignition (RCCI) engines operates has capacity to provide higher thermal efficiency, lower particular matter (PM), and lower oxides of nitrogen (NOx) emissions compared to conventional diesel combustion (CDC) operation. Achieving these benefits is difficult since real-time optimal control of RCCI engines is challenging during transient operation. To overcome these challenges, data-driven machine learning based control-oriented models are developed in this study. These models are developed based on Linear Parameter-Varying (LPV) modeling approach and input-output based Kernelized Canonical Correlation Analysis (KCCA) approach. The developed dynamic models are used to predict combustion timing (CA50), indicated mean effective pressure (IMEP), …

Depressurization Characteristics Of Steam-Based Reciprocating Vacuum Pump, Hongling Deng

Dissertations

This dissertation introduces a novel vacuum technology that leverages low-pressure saturated steam and cooling-controlled condensation, offering an efficient way to utilize low-grade thermal energy sources like waste heat, steam, or solar energy. At the heart of this technology is a unique duo-chamber vacuum pump system, featuring a reciprocating piston and a heat-conductive wall, designed to generate a vacuum through steam-condensation and cooling processes.

The core of this research lies in developing and validating mechanistic models for the steam-condensation depressurization process, a complex phenomenon involving phase change and transport mechanisms. Prior to this work, these mechanisms were not sufficiently modeled or …

Investigation Of Thermofluid Processes In A Pcm Based Thermal Storage Module, Luca M. Crnjac

Electronic Thesis and Dissertation Repository

Latent heat thermal energy storage systems can capture and store solar thermal energy, enhancing the reliability of solar energy by facilitating a continuous and consistent energy supply. However, phase change materials used in these systems suffer from low thermal conductivities making it difficult to achieve suitable charging and discharging rates. The present research investigated this issue using computational and experimental approaches to improve the design of a thermal storage module through heat transfer enhancement. Various heat transfer enhancements including a finned honeycomb structure, and metal wool were incorporated into a thermal storage module to analyze their effect on charging and …

Effects Of Back Reflectors And Thin Metal Covers On The Performance Of Near-Field Thermophotovoltaic Devices, Mehran Habibzadeh

Electronic Theses and Dissertations

Highly efficient energy harvesting devices that can recover a large amount of waste energy are of significant interest. Thermophotovoltaics (TPVs) are solid-state devices that can convert thermal energy radiated by a heated emitter into electrical power through the process of photovoltaic effect. In a TPV system, heat is converted to electricity by using a high-temperature emitter to radiate photons, which are then absorbed by a photovoltaic (PV) cell, generating electron-hole pairs and producing electrical power.

TPV devices have the advantages of producing High efficiency and being lightweight with low maintenance cost and zero pollution. However, these devices have not been …

Effect Of A Geothermal Heat Pump System On Cooling Residential Buildings In A Hot, Dry Climate, Rania Rushdy Moussa, Ayman H. Mahmoud

Architectural Engineering

ABSTRACT In the last century, electricity demand has doubled due to urban expansion, which has contributed to the formation of more urban heat islands (UHI) and the appearance of environmental hazards such as the global climate change phenomenon. Since residential buildings are considered the main electricity consumer sector in Egypt, they consume up to 42% of total energy consumption, which contributes to increasing temperatures and constitutes UHI in cities. In this context, the research aims to examine the effectiveness of using the closed vertical loop geothermal system (GSHPCV) for cooling residential buildings in a hot, dry climate, such as Cairo, …

Dynamics Modeling Of Molten Salt Reactors, Visura Umesh Pathirana

Doctoral Dissertations

The abundance of energy is a necessity for the prosperity of humans. The rise in energy demand has created energy shortages and issues related to energy security. Nuclear energy can produce vast amounts of reliable energy without many of the negative externalities associated with other competing energy sources, such as coal and natural gas. As a result, public interest in nuclear power has increased in the past decade. Many new types of nuclear reactor are proposed. These nuclear reactor designs feature many passive technologies that can operate without external influence. Reactors that feature advanced passive safety features are catagorized as …

Additively Manufactured Nature Inspired Morphology For Redesign: Advancing Next Generation Energy Systems, Vanshika Singh

Doctoral Dissertations

To meet cleaner energy goals and increasing demand, energy systems such as gas turbines and power plants are required to be operated under harsh loading conditions like higher temperatures and pressures, fluctuating loads, and corrosive environments. Advanced manufacturing techniques such as additive manufacturing (AM) have put us on the trajectory for next-generation system designs, allowing complex geometries and high-temperature alloys with tailored material properties. We need new and systematic design philosophies to use AM's unique characteristics prudently. For a given functionality, nature tends to provide similar solutions in animate and inanimate structures. We propose to take inspiration from nature's repetitive …

An Investigation Into Computational Modelling Of Melting And Solidification Of Phase Change Materials, Maryam Hemmat

Electronic Thesis and Dissertation Repository

This thesis evaluates the effectiveness of the enthalpy-porosity approach in simulating melting and solidification of phase change materials within latent heat thermal energy storage systems. It systematically investigates the sensitivity of the computational model to four adjustable parameters: mushy zone coefficient, thermal expansion coefficient, solidus/liquidus temperatures, and latent heat. The study includes individual and combined analyses of these factors in simulations of the melting process by comparing outcomes with extensive experimental data, resulting in a calibrated melting model. The calibrated model is validated across various heating conditions in the cylindrical cavity, and then in a rectangular cavity, confirming its reliability …

Application Of Wind Propulsion In The Existing Fleet Of The Caspian Sea Using Real Wind Data, Mahmud Suleymanli

World Maritime University Dissertations

No abstract provided.

Analysis Of The Pros And Cons Of The Acquisition Of Training Ships By Metis, Jeremiah Yaw Frimpong

World Maritime University Dissertations

No abstract provided.

Exploring The Role Of Education In Addressing The Skills Gap For Seafarers In Bangladesh's Maritime Industry, Fatema Tuz Tahera

World Maritime University Dissertations

No abstract provided.

Onshore Power For The Docked Container Vessels In Apapa Port Through Blended Finance, Oladayo Matthew Atilola

World Maritime University Dissertations

No abstract provided.