Combustion Characteristics And Cycle-To-Cycle Variations In A Diesel Generator Fueled With Used Frying Oil Biodiesel Blends, Shady Elmozy, Ahmad Khira Dr., E. A. El Shenawy Prof. Dr., Medhat Elkelawy Prof. Dr, Eng.

Journal of Engineering Research

This paper investigates the combustion characteristics and cycle-to-cycle variations in a stationary direct-injection diesel generator fueled with biodiesel derived from used frying oil (UFO) blended with conventional diesel. Used frying oil methyl ester (UFOME), referred to as UB100, was produced through a single-step alkali transesterification process and blended with diesel fuel in varying proportions (UB10, UB20, UB30, UB40, and UB50). Experiments were conducted on a single-cylinder, naturally aspirated diesel engine operating at a constant speed of 1500 rpm under five different load conditions: 0%, 25%, 50%, 75%, and 90%. In-cylinder pressure data from 400 consecutive cycles were analyzed to determine …

How’S It Growing? Tools For Observing Snow And Sea Ice In A Changing Arctic Ocean, Ian Alexander Raphael

Dartmouth College Ph.D Dissertations

September Arctic sea ice extent has diminished by roughly 50% in the 45 years since satellite observations began. The Arctic Ocean may experience ice-free summers within the next decade, with implications for habitat, resource extraction, geopolitics, and local and global climate change. To predict how Arctic sea ice will change in the future, we need to understand its behavior in the present. In situ sea ice mass balance measurements (snow accumulation, ice growth, snow and ice surface melt, and bottom melt) are essential for studying the processes driving rapid changes in the ice pack, and for validating remote sensing measurements …

Brush Seal Cycling Test Rig, Angelo J. Reis, Neil M. Bedagkar, Max A. Soury, Eoin K. Lenham

Mechanical Engineering

To prevent backflow from the high pressure compressor stages of their gas turbines to lower pressure regions, Solar Turbines utilizes brush seals along their driveshafts. Due to manufacturing limitations, no shaft is perfectly symmetric about its rotating axis, leading to orbiting that creates asymmetric friction on the shaft through rubbing. With this biased application of friction comes a hotspot on one side of the shaft, causing bowing of the shaft and cascading into an amplified vibrational response. Our goal is to gather data on this phenomenon and offer a potential solution.

Air To Water Capture In Support Of Un Sustainable Development Goals, Jordan Macconnell, Michael Tiscareño, Ari Dennis, Baxter Mercy

Mechanical Engineering

This senior project explored the use of thermoelectric cooling for atmospheric water capture. The system was designed to cool aluminum condensing surfaces below the dew point using Peltier modules, with forced convection heat sinks on the hot side. The purpose of this system was to gather reliable amounts of water for various water-scarce areas around the world to help meet the UN's sixth Sustainable Development Goal.

The final design of this project consisted of a 1.5 x 1.5 x 2 foot frame made of acrylic panels and insulation. Within the frame, the thermoelectric system was constructed using Peltier modules with …

Multimodal Self-Folding Of Shape Memory Polymer Using Laser Induced Graphene, Liam Harrison Drew

Master's Theses

Shape memory polymers (SMPs) can undergo programmed shape transformations when heated above their glass transition temperature (T_g), enabling actuation through stimuli such as infrared (IR) radiation and Joule heating. These materials are promising for deployable systems and soft robotics due to their lightweight structure and elimination of traditional mechanical components. While IR-based actuation is simple and low-cost, it lacks precision in uncontrolled environments. Joule heating offers improved control but is often limited by conductive ink properties such as thickness, stiffness, or poor adhesion. This work introduces a novel method for multimodal SMP actuation using laser-induced graphene (LIG) transferred …

Cryogenic Fuel Delivery System, Carter Josef, Reilly Humphreys, Joseph O'Connor, Nick Spreen

Mechanical Engineering

This project presents the design and validation of a cryogenic fuel delivery system aimed at enabling sustainable aviation through hydrogen fuel vaporization. Developed by a team of senior mechanical engineering students at Cal Poly and sponsored by Boeing, the system utilizes atmospheric air to vaporize liquid nitrogen, used as a stand-in for hydrogen, via forced convection heat exchangers, eliminating the need for engine-supplied heat and reducing parasitic loads. A feedback loop and turbine component are integrated to regulate pressure and recover energy, respectively. A benchtop prototype was built and tested to evaluate system performance, with results closely aligning with analytical …

Combustion Liner Optimization, William Weeks, Daniel Reed, Isaac Trull

Mechanical Engineering

Solar Turbines provides gas power generation solutions, focusing on gas turbine engines and compressors. The Gas Turbine Products Engineering (GTPE) team at Solar Turbines needs a way to efficiently and cost-effectively maintain the combustion liner of the Taurus model gas turbine at or below the cold-side temperature target. The current system involves a manufacturing process with ergonomic concerns and uncertain cooling effectiveness.

To address this, our team proposed a new combustion liner system featuring impingement cooling. We provided Solar Turbines with heat transfer models of both the existing and proposed designs, demonstrating improved cooling performance. Additionally, a prototype of the …

Fire Fossils: Biomineral Infrastructures In Untangling Climates, Tanmayee More

Masters Theses

Diatoms drift, sediments sink, wildfires generate their own weather. Lightning strikes can blast sand into glass, and microscopic organisms do the same in the cold recesses of the ocean. What alchemies and metabolisms catalyze space, time, and energy? What are the thermodynamics of infrastructure in Climate Change?

Places, materials, and beings are afterimages. Through alchemical experiments, and multi-scalar imaging, I develop simulations of wildfires, and their profound, reverberating effects. In this thesis, a glass-meets-landscape experimental process enters these obscured conditions and renders new material relations for the built environment.

Effects Of Thermal Interface Materials On Thermal Conductivity Measurement Using A Modified Astm D5470 Thermal Resistance Tester, Chinmaya Joshi

Mechanical Engineering Undergraduate Honors Theses

In this paper, we have investigated the effect of thermal interface materials (TIMs) on the accuracy and uncertainty of thermal conductivity measurements. A modified ASTM D5470 thermal resistance tester (TRT) is developed to measure the out-of-plane thermal conductivity of pyrolytic graphite (PG) and grade 2 titanium (TiG2) with and without TIMs. Compared to the ASTM D5470 standard, this modified design uses three thermocouples per side to support regressive analysis and explores the use of TIMs.s Nine PG samples and four TiG2 samples of varying thickness have been tested to obtain thermal resistance as a function of sample thickness. The steady-state …

Experimental And Computational Investigation Of Using Passive Sweeping Mist Jet Film Cooling Via Fluidic Oscillators In The Gas Turbine Application, Mohammad Javad Mohaghegh Kojidi

LSU New Orleans Theses and Dissertations

As the energy industry transitions to cleaner fuels like hydrogen, the resulting higher flame temperatures pose significant challenges for gas turbine cooling. Mist-enhanced film cooling using sweeping jets, generated by passive fluidic oscillators, offers a promising solution by providing wider and more uniform coolant coverage. This study combines computational and experimental (using Particle Droplet Phase Analyzer) approaches to evaluate sweeping mist jet performance.

Simulations were conducted under laboratory conditions to investigate the influence of droplet wall boundary conditions—reflect, trap, and wall-film—on cooling effectiveness and droplet dynamics. The wall-film model, motivated by observed liquid streaks, demonstrated the best agreement with experiments. …

Uncertainty Quantification Of Turbulent Premixed Flames, David L. Brown

Honors Theses

This thesis presents an uncertainty quantification (UQ) study of turbulent premixed flames, focusing on the impact of uncertainties in operating conditions on the normalized consumption speed. Namely, temperature, pressure, and equivalence ratio are the operating conditions that are under study. Due to significant computational demands associated with direct MC methods for UQ, surrogate modeling techniques including Polynomial Chaos Expansion (PCE), Stochastic Collocation (SC), and Gaussian Process (GP) are evaluated based on efficiency and accuracy. Through this study, PCE is identified as the optimal surrogate model due to its accuracy and significantly reduced computational costs. PCE is subsequently applied to investigate …

Validating An Electronics Cooler Experiment And Optimizing Its Performance Using Ansys Icepak, Daniel V. Curl

Mechanical Engineering Undergraduate Honors Theses

Researchers at the University of Arkansas' Mechanical and Electrical Engineering Research Departments have designed and built a cold plate and substrate design for a 10 kV SiC MOSFET power module. Many variables define the design of the cold plate and substrate system and have quantifiable effects on the device’s performance. These variables include but are not limited to geometry and material selection of the fins and substrate. Manufacturing many test designs, running experiments, and comparing their performance is a time-consuming and expensive design optimization method that may be effective for some low-cost applications. Still, simulation is often a more cost-effective …

Introduction To Building Energy Modeling And Analysis Using Energyplus, Jackson C. Burnett

Mechanical Engineering Undergraduate Honors Theses

Retail stores are dynamic environments where human activities significantly influence energy consumption patterns, particularly affecting heating, ventilation, and air conditioning (HVAC) demands. Existing energy models, such as those developed using EnergyPlus, often rely on generalized assumptions about human occupancy and behavior, leading to discrepancies between predicted and actual energy usage. This research aimed to enhance the accuracy of energy modeling for retail stores by conducting a sensitivity analysis of occupancy using EnergyPlus simulations. The study investigated how variations in occupancy levels impact HVAC loads, cooling and heating demands, and overall energy use. Results showed that increasing occupancy leads to higher …

The Effects Of Geometric Shape And Power-Law Index On The Thermal Activity And Dynamic Behavior Of A Complex Fluid, Houssem Laidoudi

Emirates Journal for Engineering Research

The paper presents numerical results for non-Newtonian fluid confined horizontally between two rings. The outer ring has a circular shape, low temperature and rotates at a constant and uniform speed, while the inner ring has different shapes (circular, square and triangular), is constant and has a high temperature. This study aims to determine the method and the amount of heat transfer between the rings and under the influence of these factors: the rheological coefficient of the fluid, known as the power-law index, thermal buoyancy intensity, the rotation speed of the outer ring and the geometric shape of the inner ring. …

Experimental Investigation Of Heat Transfer To Tightly Packed Cylinder Arrays, Cameron M. Sexsmith

Doctoral Dissertations and Master's Theses

With the increased emphasis on the development of hybrid electric aircraft and other electric driven vehicles, the thermal demand on batteries is increasing. Unique to the aviation sector is the combined need of high battery thermal loads and a light-weight thermal management system. A proposed configuration is an array of batteries directly cooled with a dielectric coolant. The knowledge of heat transfer characteristics of battery cooling is becoming an ever pressing issue due to the need to optimize volume and mass in a safe manner. Tighter spacings between batteries provide higher pack densities, however, at the cost of increased cooling …

Numerical Investigation Of Heat Transfer And Pressure Drop In A Circular Microchannel Using Sio₂ Nanofluids, Mahmoud G. Abdelfatah, Osama E. Abd-Ellatif, Ahmed A. A. Attia, Abdelrady O. Elnady

Journal of Engineering Research

A numerical investigation was conducted to analyze the flow characteristics and heat transfer performance of a circular microchannel. using water and SiO₂+pure water nanofluids with volume fractions of 0.3%, 0.7%, and 1%. The microchannel was subjected to a constant heat flux of 100W, and the pressure drop, friction factor, and thermal resistance were evaluated for different Reynolds numbers ranging from 250 to 850. The results show that the addition of SiO₂ nanoparticles enhances the thermal performance of the microchannel by reducing the thermal resistance by up to 1.9% compared to pure water. However, the pressure drop increases with higher Np …

The Spice (Sustainable, Physics-Inspired Culinary Education) Lab – A Digestible Few-Nexus Educational Platform, Carla Ramsdell

National Collaborative for Research on Food, Energy, and Water Education (NC-FEW)

The SPICE (Sustainable, Physics-Inspired Culinary Education) Lab is a unique educational platform that enables participants from a wide disciplinary background to engage and become literate in the unique connections between food, energy and water. This small but mighty space allows for outreach education in many formats, including formal college courses, university-centered hands-on activities and public outreach.

The work performed in this space fills a unique need in the FEW-Nexus education opportunities because it is adaptable to many learners and learning opportunities and its focus on kitchen science makes these concepts approachable which can later be expanded to understand other critical …

Design, Test, And Comparison Of A Photovoltaic Thermal Hybrid Solar Collector Utilizing A Thermosiphon, And Theory And Analysis Of Related Predictive Computer Model, Lance Brown

Master's Theses

Design, construction and testing of a photovoltaic thermal collector, or PVT, was completed to determine efficiency improvements of this system compared to a conventional solar panel and to find the thermal energy gained through hot water storage. Flow, driven by density changes from solar radiation, creates a thermosiphon, moving water without the use of a pump and ultimately drawing heat away from the solar panel. This is done to create a more efficient solar panel as well as decreasing potential damage due to high temperatures. Evaluation of electrical efficiency, thermal efficiency and flowrate allow for comparison between other PVT systems. …

Numerical Simulation Of Airflow Properties Of The Naca 6420 Airfoil Using The Transition Rans K-Ε Model, Oluwaseyi O. Alabi, Saidat A. Salisu, Oyeyemi T. Aforolagba -Balogun, Temitope A. Ladigbolu, Ayotunde O. Fasina, Anas Bala

Al-Bahir

This study investigates the airflow properties around the airfoil using numerical simulation, addressing the longstanding challenge of accurately predicting transition phenomena in turbulent flows. The importance of this research lies in its potential to improve the design and performance of airfoils in various engineering applications, such as wind turbines, and aircraft. A custom 2-dimensional airfoil model was created using Airfoil instruments, featuring a 6% maximum curvature, 40% curvature position, and 20% thickness. COMSOL Multiphysics software performed computations at a velocity of over 19 hours, with data analyzed at 60-minute intervals. The Transition turbulent model was employed to simulate the airflow …

In-Situ Thermal Measurement Of Polymers, Carson Powers, Jungkyu Park, Dal Hyung Kim, Fahim Dorsey, Peter Bearden

Symposium of Student Scholars

In this research, we conducted a detailed experimental

investigation into how strain affects the thermal conductivity of

Ecoflex elastomer, utilizing a newly developed method for

measuring thermal conductivity under mechanical strain for the

first time. In situ thermal conductivity measurement apparatus

was developed by combining the KLA T150 nanoscale tensile tester

and a custom-fabricated thermal measurement sensor. The

development of an experimental method for measuring the thermal

conductivity of nanomaterials under mechanical testing

simultaneously will contribute to the development of novel

materials for flexible electronics by helping us to better

understand the strain effect on their thermal performance.

Interestingly, the …

A Review Of Performance Assessment Of Solar-Driven Absorption Chillers Incorporated With Energy Storage Systems, A. Khalil, Mohamed Abdelgaied, May Abdelsalam

Journal of Engineering Research

Abstract- This study evaluates the performance of a solar

collector absorption chiller combined with Phase Change Material (PCM) energy storage devices. Solar energy is used for energy-efficient cooling, and PCM storage improves

efficiency by capturing surplus thermal energy during

abundant solar radiation and releasing it when insufficient. The research assesses performance measures like

COP, energy storage capacity, and overall system efficiency.

Experimental And Numerical Modelling-Based Optimization Of Additive Manufacturing Processes, Vishnu V. Ganesan

Mechanical and Aerospace Engineering Dissertations - Archive

ABSTRACT

Experimental and Numerical Modeling-Based Optimization of Additive Manufacturing Processes

Vishnu V Ganesan, Ph.D.

The University of Texas at Arlington, 2025

Supervising Professor: Dr. Ankur Jain

Experimental and numerical modeling play a pivotal role in advancing additive manufacturing technologies by enabling a deeper understanding of complex, multi-physics processes that govern part quality, performance, and reliability. These manufacturing techniques—ranging from Powder Bed Fusion (PBF) and Material Extrusion (MEX) to Automated Fiber Placement (AFP)—involve tightly coupled thermal, mechanical, and material phenomena that are challenging to capture through empirical observation alone. Experimental methods offer critical validation and insights into real-world behavior, while numerical …

Deep Neural Network Models For Heatsink Performance Prediction And Optimization In Single Phase Immersion Cooling: Framework For Future Design Tools And Digital Twin Integration, Braxton J. Smith

Mechanical and Aerospace Engineering Theses - Archive

The rapidly rising computational power of modern computing components combined with the advanced packaging techniques being implemented has resulted in exponentially increasing thermal design powers (TDP) from CPUs and GPUs. Traditional air-cooling methods are approaching their effective cooling limits for many of these components, requiring lower supply air temperatures, higher supply air flowrates, and much larger heatsinks to remain feasible. Transitioning from air-cooling to single-phase immersion cooling offers numerous benefits in thermal performance, data-center size reduction, and energy efficiency. To leverage the merits of immersion cooling, the performance of a given heatsink must be predicted and optimized for best performance …

Materials Reliability In Direct-To-Chip Cooling: A Systematic Study Of Aluminum Corrosion In Next-Generation Data Center Coolants, Fnu Harish Gangadhara

Mechanical and Aerospace Engineering Theses - Archive

Data centers are rapidly scaling to support artificial intelligence, cloud platforms, and other high-performance workloads, driving a sharp increase in chip and rack power densities that are now approaching, and in some cases surpassing, 50–100 kW per rack. In response, direct-to-chip liquid cooling has become a key enabling technology for managing these extreme thermal loads, yet the durability of materials in contact with the coolant remains a major reliability concern over system lifetimes. Copper has traditionally been used for cold plates and cooling-loop components, but its relatively high cost, mass, and supply-chain uncertainty are motivating a shift toward aluminum as …

From Spark To Wildfire: Predicting Wildfire Origins And The Efficacy Of “Fire Safe” Cigarettes In California Grasslands, Trevor Blackwell Haltermann

Cal Poly Humboldt theses and projects

As wildfires in North America increase in size and frequency, the societal impacts become greater as well. With greater risk and high fire suppression costs it is pertinent to improve fire investigation methods and limit the potential for human caused ignitions. Two distinct studies were carried out to assess the accuracy of fire pattern indicators and the efficacy of “fire safe” cigarette technology in lowland grass fuel types in California. The first study utilized 24 experimental small-scale fires within a wind tunnel to examine the accuracy of microscale fire pattern indicators and the factors that influence the accuracy of predictions …

Optimizing Material Selection And Operational Conditions For Xhv Systems: Lessons From Aisi 1020 And 316l Comparative Studies, Aiman H. Al-Allaq, Md Abdullah Mamun, Matt Poelker, Abdelmageed Elmustafa

Mechanical & Aerospace Engineering Faculty Publications

In this study, AISI 1020 low-carbon steel was investigated as a cost-effective alternative to SS316L stainless steel for reaching extreme high vacuum (XHV) conditions. After being baked at 400°C, a vacuum chamber made of low-carbon steel material exhibited an outgassing rate approximately 2000 times smaller than a similar chamber made of stainless steel. Its activation energy for hydrogen diffusion (27 kJ/mol) is less than half that of stainless steel (60.3 kJ/mol), indicating more efficient hydrogen removal during bakeout. MolFlow+ simulations supported the experimental data and demonstrated the importance of system geometry optimization and minimizing stainless steel content for achieving optimal …

Growth Kinetics And Stability Of Metal Halide Perovskite Nanocrystals: Influence Of Stirring Speed And Water Exposure, You-Lin Huang

Theses and Dissertations--Mechanical and Aerospace Engineering

Cesium lead bromide (CsPbBr₃) perovskite nanocrystals (NCs) have garnered significant interest due to their exceptional optoelectronic properties, including high photoluminescence quantum yield, tunable bandgap, and excellent carrier dynamics. These attributes make them promising candidates for applications in light-emitting diodes, photovoltaics, and sensing technologies. However, optimizing their synthesis and improving their environmental stability remain critical challenges. This dissertation explores the growth kinetics of CsPbBr₃ NCs, focusing on the effects of stirring speed and water exposure on their structural and optical properties.

The synthesis of CsPbBr₃ NCs was performed using both mechanochemical (MC) and antisolvent methods, enabling an …

Fabrication And Characterization Of Cast Copper Heatsinks For Computer Chip Cooling, John James Recktenwald

Graduate Theses, Dissertations, and Problem Reports (ETD)

Humanity has worked copper for millennia, from primitive tools in prehistory to the wires and cooling solutions facilitating the modern digital age. While high performance fin style heatsinks are commonplace, more complex heatsink geometries in high performance applications are rare due to manufacturing challenges. In this study a casting process was developed to fabricate copper pin fin heatsinks. To assess the performance of heatsinks fabricated using the process three pin fin heatsinks were fabricated, one machined from a commercially manufactured billet, one machined from a cast block, and one cast directly to final shape. Each of the three heatsinks were …

Microwave-Assisted Reduction Of Critical Metal Oxides From E-Waste Mixture, Kurundu Shavinka Jayasekera

Graduate Theses, Dissertations, and Problem Reports (ETD)

The efficient recovery of critical metals such as tantalum (Ta), manganese (Mn), gallium (Ga), and indium (In) from electronic waste (e-waste) is essential for resource sustainability and environmental protection. This research uses microwave-assisted treatment to investigate the carbothermal reduction of these four specific metals from their oxides in a simulated e-waste mixture, with carbon black serving as both a microwave coupling and reduction agent. Microwave processing is used specifically because it offers a rapid and energy-efficient alternative to conventional thermal methods, with the benefits of intrinsic heating and selective heating of materials. The first experiments centered on understanding the effects …

Multiphysics Modeling Of Solid Oxide Fuel Cells For Gradient Minimization And Inductive Loop Analysis In Impedance Spectroscopy Using Machine Learning-Based Microstructural Property Estimation, Muhammad Usman Khan

College of Graduate Studies: Theses & Dissertations

Solid oxide fuel cells have significant advantages in renewable energy utilization due to their high efficiency, fuel flexibility, and low emissions. However, despite the numerous efforts of technology, thermal and current density gradients and impedance behavior fluctuations are still causing performance degradation. A combined computational framework that integrates machine learning and three-dimensional Multiphysics modeling is needed to investigate and optimize the performance of solid oxide fuel cells. A machine learning model, trained on synthetic microstructure data by percolation analysis, is used to predict important microstructural parameters like triple phase boundary density and geometric tortuosity. These are then employed in a …