Mechanical Engineering Commons^™

On The Structure, Energy, And Segregation Behavior Of Grain Boundaries In Metallic Systems, Yasir Mahmood

All Dissertations

Nearly all structural metallic systems are multi-component polycrystalline aggregates; their microstructures are composed of crystalline grains that are internally joined at grain boundaries (GBs). This thesis focuses on GB structure, energy, and chemistry, as these greatly influence many material properties and processes, including boundary dynamics during processing treatments or under operating conditions.

Using atomistic simulations, we examine the impact of metastable GB structures on solute segregation. A wide range of GB geometries and metastable structures are used in our study. The Al-Mg alloy is used because it is of interest for light weighting. The atomistic simulation results are used to …

Linear And Nonlinear Topology Optimization With Morphing Beam Networks, Andrew S. Montalbano

All Dissertations

Topology optimization (TO) is an engineering design discipline dedicated to optimizing material distribution within a given domain. In traditional gradient-based topology optimization, the solid domain is discretized into small volumetric elements. Using finite element analysis (FEA) of the structure, the gradient of the objective function with respect to the design variables (the pseudo densities) is computed, and these design variables are updated iteratively until convergence is achieved. Although gradient-based TO methods are well-established, sensitivity analyses of objective functions and constraints can be both mathematically complex and computationally intensive. The nonconvex nature of most TO problems often complicates efficient convergence. Furthermore, …

Hybrid Physics-Infused Machine Learning Framework For Fault Diagnostics And Prognostics In Cyber-Physical System Of Diesel Engine, Shubhendu Kumar Singh

All Dissertations

Fault diagnosis is required to ensure the safe operation of various equipment and enables real-time monitoring of associated components. As a result, the demand for new cognitive fault diagnosis algorithms is the need of the hour. Existing deep learning algorithms can detect, classify, and isolate faults. Still, most depend solely on data availability and do not incorporate the system's underlying physics into their prediction. Therefore, the results generated by these fault-detecting algorithms sometimes need to make more sense and deliver when tested in actual operating conditions.

Similar to diagnosis, the fault prognosis of diesel engines is paramount in numerous industries. …

Utilizing Bayesian Optimization In Technoeconomic Analyses For Integrated Energy Systems, Anthoney Griffith

All Graduate Theses and Dissertations, Fall 2023 to Present

Technoeconomic analysis is a key element in the study of integrated energy systems. The goal of this analysis is the sizing of technologies resulting in the best economic outcome for the system. The evaluation of this system involves sizing the components and simulating the resulting market to determine an outcome. This simulation incorporates multiple possible values of uncertain parameters like grid price and wind generation. This problem is currently approached with the gradient descent optimization method. An alternative approach, Bayesian optimization, sees success on simple problems of a similar nature to technoeconomic analyses. These results motivate applying Bayesian optimization as …

Development Of A High-Throughput Methodology For Vibration-Based Fatigue Tests, Brandon Alexander Furman

All Graduate Theses and Dissertations, Fall 2023 to Present

Global efforts towards the development of additively manufactured materials, biomaterials, metamaterials, self-healing materials, and composites have reached a staggering pace. With new materials being developed on a near-daily basis, it is more important than ever to be able to quickly and precisely quantify their mechanical performance. However, one of the most important mechanical properties, fatigue life, is notoriously time consuming to measure. Consequently, fatigue parameters are often calculated based on small sample sizes, resulting in high uncertainty of the measured parameters. In this dissertation a high-throughput approach to fatigue measurements is developed. This technique allows for multiple samples to accumulate …

Understanding Ion Rejection Mechanism Of Freeze Desalination By Molecular Dynamics Simulation, Mahbuba Jannat

All Graduate Theses and Dissertations, Fall 2023 to Present

This study explores a method called freeze desalination, which uses the natural process of ice formation to remove salt from water at lower than freezing temperature of water, which is 235K (Freezing temperature of this water model is 249K), making it safe for potable water. Unlike traditional methods, freeze desalination can be more efficient and environmentally friendly, but how it rejects salt at the molecular level is not very clear to understand. Using molecular dynamics simulation, this research aims to uncover the details of this process. We focused on understanding how water molecules interact with salt ions during freezing. Our …

Dynamic Modeling Of A Nuclear Integrated Energy System With Thermal Energy Storage And Hydrogen Production, Seth J. Dana

All Graduate Theses and Dissertations, Fall 2023 to Present

Historically, nuclear reactors have used water for cooling and moderating the nuclear reaction within the core. Advanced generation IV nuclear reactors currently under development are designed with different coolants which enable operation at higher temperatures. A higher operating temperature makes nuclear power suitable for co-located hydrogen production via high temperature electrolysis. Natrium, an advanced reactor design by TerraPower and GE Hitachi, combines a sodium fast reactor with molten salt thermal energy storage. The work presented in this thesis models and analyzes three Natrium systems which integrate hydrogen production with the Natrium nuclear power plant. The first two configurations focus on …

Trade-Offs In Lighting For Dic Strain Measurements In Vibration-Based Fatigue Testing, Jacob R. Rigby

All Graduate Theses and Dissertations, Fall 2023 to Present

Vibration based fatigue testing offers a fast and efficient method for determining the breaking point of a material. This method often uses a device, called a strain gage, to measure the deformation of a test sample at a single spot on the test sample. However, these strain gages often break before testing is complete. To overcome this premature break, a laser vibrometer is often used to measure the amount of movement or the speed of the test sample throughout the vibration test. The deformation measured by the strain gage is compared against the amount of movement or velocity of the …

Rapid Prediction Of Buoyancy-Driven Exchange Flows At The Great Salt Lake: Ml Models And A 1d Shallow Water Approach, Eric M. Larsen

All Graduate Theses and Dissertations, Fall 2023 to Present

The Great Salt Lake in Utah, USA, is a hypersaline terminal lake divided in to northern and southern arms by the Union Pacific Railroad causeway since the 1950's. This separation has caused a difference in density and water surface elevation between lake arms. These differences result in a buoyancy-driven exchange flow occurring through an engineered breach in the causeway. Traditionally, modeling the flow through the breach has been done by numerically solving the 1D steady shallow water equations, and using computational fluid dynamics (CFD). The CFD models yield high accuracy results, but require substantial computing resources. This research proposes the …

Development Of A Passive Drag Reduction Modification For The 25° Ahmed Body Using Large Eddy Simulation, Skylar Polek

UNLV Theses, Dissertations, Professional Papers, and Capstones

In the field of automotive aerodynamics, the Ahmed body is a generic vehicle-shaped bluff body which is meant to generalize the rear end of fastback and hatchback vehicles. Specifically, an Ahmed body with a rear slant angle of 25° has seen common use due to its resemblance of common rear windshield shapes as well as its notoriously complex wake structure. This research focuses on simulating the flow over a 25° in various situations with an ultimate goal of drag reduction. First, a simple benchmark of the k-ω shear stress transport (SST), large eddy simulation (LES) with the Smagorinsky-Lilly subgrid scale …

Dynamic Model Of An Overhead Crane, Leonard Ruesga

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this thesis a novel spatial model of an overhead crane was developed. The model includes: bridge, trolley, driving and follower wheels for the bridge and trolley, drum, cable, and the payload. The model accounts for the winding/unwinding of the cable around the drum as the payload is raised/lowered. The cable and the payload were considered as rigid bodies with uniformly distributed mass. First, the kinematic equations of the model were developed by using constraint equations. Second, the dynamic equations were derived through use of Newton’s Laws. Developing the rotational dynamic equations required the determination of the angular momentum vectors …

Smart Automatic Modal Hammer Predictor–Corrector Approach For Accurate Excitation Of Dynamical Systems, Mohammad Nasr

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

This research introduces an innovative solution that revolutionizes the study of linear and nonlinear dynamical systems—a smart automatic modal hammer. With its affordability and intelligent capabilities, this automatic modal hammer becomes an invaluable tool for research and industry, enabling repeatable strikes with precise force control. This system's significance becomes particularly evident when studying nonlinear systems, which heavily rely on the excitation level for their dynamics. By offering a cost-effective design this proposed system proves to be robust in accelerating research on nonlinear dynamics, providing researchers with an efficient and accessible means to delve deeper into these complex systems. The proposed …

Ultrasonic Nondestructive Quantification Of Case Depth In Railroad Bearing Components, Trevor K. Adelung

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

While in service, railroad bearings must withstand large loads to ensure smooth operation. These large loads can lead to failure due to rolling contact fatigue (RCF), for which small cracks initiate just beneath the surface of the components. As a preventative measure, bearings are manufactured with a hardened surface layer called the effective case depth (ECD). Current methods in industry use destructive hardness testing to quantify the ECD. While accurate, this method is costly and time consuming. Ultrasonic nondestructive testing would provide a more efficient and cost-effective method to determine ECD. In this thesis, diffuse ultrasonic shear backscatter was used …

Studies Of Exotic Electronic, Optical, And Electrochemical Properties In Nanoparticle Assembly And Graphene, Jay Min Lim

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

It is well known that exotic properties and phenomena emerge as structural dimensions shrink to nanoscales. We self-assembled one-dimensional chains of gold nanoparticles in solution and quantified the growth process by monitoring the redshift of localized surface plasmon resonance (LSPR). Curiously, the redshift stopped while the chains continued to rearrange as manifested by gradual reduction in the LSPR peak. Using electromagnetic simulations, we quantitatively explained the phenomena as a rapid “addition-polymerization” followed by a sharp transition to “condensation-process.” Next, recognizing the significant electric field enhancement in the interparticle gap, a photoluminescent-active Eu³⁺ ion was used to probe Surface-Enhanced Photoluminescence …

Wind Turbine Power Phase Control With Dc Collection Bus For Onshore/Offshore Windfarms, Wayne Weaver, David Wilson, Rush Robinett

Michigan Tech Patents

A DC bus collection system for a wind farm reduces the overall required number of converters and minimizes the energy storage system requirements. The DC bus collection system implements a power phasing control method between wind turbines that filters the variations and improves power quality. The phasing control method takes advantage of a novel power packet network concept with nonlinear power flow control design techniques that guarantees both stable and enhanced dynamic performance.

Tuning Of Real-Time Optimization Of Heliostat Concentrated Solar Power, Zachary L. Bernius

Mechanical Engineering ETDs

This paper investigates a real-time optimization algorithm for autonomously calibrating the heliostats in a concentrated solar power plant with the goal of maximizing power generation. The current state-of-the-art uses human operators to provide feedback for the heliostats. We use real-time/online measurements to produce an autonomous closed-loop system that does not require human intervention. The paper investigates tuning the gain of the real-time optimization algorithm to quickly and robustly converge to the optimal alignment and stabilize the system. The exponential stability of the system is certified using a quadratic Lyapunov function and static output feedback methods to couple the Lyapunov functions …

The Role Of Sensing Modalities In Shaping Collective Motion And Group Behavior, Poorendra P. Ramlall

Doctoral Dissertations and Master's Theses

Collective behavior refers to the coordinated movements that emerge from simple interactions between individuals within a group. Traditionally, researchers have modeled these interactions assuming individuals can sense their surroundings in all directions, like having eyes all around their heads. While this is a useful simplification, it does not capture the diverse ways animals actually sense the world. In this thesis, we take inspiration from the natural world, particularly from animals like bats and dolphins that use a combination of hearing and sight to navigate their environments. We explore how combining these sensory cues in a three-dimensional space affects the way …

Analysis Of Ballistic Capability In Making Bulletproof Multilayers Using Woven Ramie Fiber, Hardfacing Metal With Epoxy Matrix For Bulletproof Vests, Rizal Wahyu Permana, Syamsul Hadi, Bima Cahya Maula Dana

Journal of Mechanical Engineering Science and Technology (JMEST)

Bulletproof material in level III bulletproof vests must be created using hard and soft materials to prevent bullet penetration. Kevlar and SiC + PE are imported materials used as armor in bulletproof vests. The use of Kevlar and SiC is very dependent on foreign sources with high prices. An innovation was carried out by making bulletproof material using cheaper multilayer methods involving metal from hardfacing welding as a hard layer and ramie fiber as a soft layer with an epoxy matrix. To see the level of penetration and surface morphology structure in the specimens, 9 variations were made: 3 layers …

Study Of A Remote Wind Resource Assessment System Integrated With Internet Of Things, Filian Arbiyani, Filbert Filbert, Anthony Nathanael Theo

Journal of Mechanical Engineering Science and Technology (JMEST)

Wind energy is an emerging and popular source of clean energy due to its non-polluting nature and low cost. The efficient use of wind energy requires accurate and precise wind parameter measurements, which is where wind resource assessment (WRA) comes into play. The IoT and cloud-based systems have been applied to remote monitoring systems and provide crucial solutions for data acquisition, storage, and analytics in wind energy technology. This study aims to build a remote WRA system integrated with the Internet of Things. This study utilizes an Arduino Uno microcontroller, RK100-01 wind speed sensor, BMP280 temperature and pressure sensor, and …

Metal Casting Furnace Design Development Using Computer Simulation, Ramadhan Wahyu Irianto, Yanuar R.A. Pradana, Suprayitno Suprayitno

Journal of Mechanical Engineering Science and Technology (JMEST)

Metal foundries still rely heavily on crucible furnaces. The current furnace design, which is currently being used by the partner industry, has been found to be not properly designed and will result in a reduction in efficiency. CFD simulation will be used to find the optimal melting furnace design. This research simulation consists of 3 stages: pre-processing, solving, and post-processing. There are two furnace geometries, cylindrical and hexagonal, while the burner location will be divided into 3 positions, namely P1, P2, and P3. The most optimal furnace design will be used as a basis for the verification testing process. The …

Evolution Of Residual Stress, Crystal Orientation, And Texture On Preheating Weld Treatment Of Low Carbon Steel Astm A572 Grade 42, Suratno Adi Saputro, Andoko Andoko, Poppy Puspitasari

Journal of Mechanical Engineering Science and Technology (JMEST)

Preheating is one type of heat treatment on the material prior to starting the welding process by increasing the temperature of the material. It is used to reduce the cooling rate during the welding processes to minimize the risk of residual stress and cracking during welding. Besides the benefits of welding, it also has a negative impact, especially on the integrity of the material, because the heating process at high temperatures will cause residual stress, which will affect the mechanical properties, chemical composition, and microstructure of the material, especially on Heat Affected Zone (HAZ). This study aims to analyze the …

Static And Modal Analysis Of A Box Structured Satellite Deployment Mechanism With Self-Actuated Torsion Joint, Dongping Sheng, Renzhe Ma, Chun Su

Journal of Mechanical Engineering Science and Technology (JMEST)

A brand-new satellite deployment mechanism with boxed structure and self-actuated torsion joints is proposed and an effective method to verify the feasibility of this mechanism is established in this paper. This mechanism has the characteristics of high base frequency, high ratio of deployed and folded space occupation ratio. In order to meet the design requirements, the related analysis and optimization need to be conducted, and several conclusions are obtained. Firstly, the modal analysis of deployment mechanism at folded and fully deployed state is analyzed, and the result showed that the proper wall thickness is the key parameter to satisfy the …

A Review Of Fault Detecting Devices For Belt Conveyor Idlers, Fahad Alharbi, Suhuai Luo

Journal of Mechanical Engineering Science and Technology (JMEST)

The shift towards automated inspection methods represents considerable progress in conveyor system maintenance, enhancing safety and efficiency while posing challenges in data analysis and implementation costs. This study critically analyses sensor technologies and inspection methods for detecting faults in conveyor belt idlers, highlighting their essential role in preserving the operational integrity of industrial conveyor systems. By synthesizing various research findings, the study assesses the effectiveness of different sensor devices in identifying defects, including built-in sensors, fixed sensor options like acoustic, ultrasonic sensors, cameras, accelerometers, and Distributed Optical Fibre Sensors (DOFS), as well as mobile sensor systems. Our findings emphasize the …

Simulation Of The Performance Of Kevlar Impregnated Shear Thickening Fluid Ballistic Test Results, Ridwan Prasetya, Andoko Andoko, Suprayitno Suprayitno

Journal of Mechanical Engineering Science and Technology (JMEST)

This study explores the enhancement of Kevlar fabric’s ballistic performance through impregnation with Shear Thickening Fluid (STF) for potential application in soft body armor. The experimental approach often fails to elucidate mechanical phenomena critical for the development of lightweight and high-strength body armor designs. To address this limitation, the finite element method, specifically using ANSYS/LS-DYNA R.13, was employed for a comprehensive analysis. The simulation aimed to evaluate the impact of STF on Kevlar fabric by assessing projectile velocity, force exerted by the projectile onto the fabric, displacement, stress distribution, and fabric failure mechanisms. Kevlar yarn was modeled as a shell …

Analysis Of Avgas Fuel Spraying Schemes Using The Ansys Application Approach, Dimas Endrawan Putra, Nasrul Ilminnafik, M Fahrur Rozy Hentihu, Muh. Nurkoyim Kustanto, Danang Yudistiro, Skriptyan N.H. Syuhri

Journal of Mechanical Engineering Science and Technology (JMEST)

Avgas fuel consumption on Cessna trainer aircraft is very high. However, there has been little research regarding spray impacts in Cessna aircraft engines. The phenomenon of avgas spray colliding with the cylinder wall may occur during fuel injection, resulting in a changed spray radius and height, which will affect the mixing of fuel and air. In several aspects, this affects engine performance and exhaust emissions on Cessna aircraft. This research aims to determine and study the phenomenon of spray impact on avgasfueled aircraft engines. The fuel spray in the study occurred in the combustion chamber using pressure from a fuel …

Effect Of Addition Titanium Dioxide Nanoparticle On Properties Of Pineapple Leaf Fiber Mediated Tempo Oxidation, Rahmad Ikrom Ramadhan, Heru Suryanto, Ahmad Atif Fikri, Aminnudin Aminnudin, Jibril Maulana, Faqih Fadillah, Mohamed T. Mito, Kemal Masera

Journal of Mechanical Engineering Science and Technology (JMEST)

Indonesia is an agricultural country with the potential to grow many plants as natural fiber sources. In order to improve its properties, natural fiber needs to be treated by applying nanomaterial so that it can compete with the characteristics of synthetic fibers. The study aims to determine the influence of adding titanium dioxide (TiO2) nanoparticles on pineapple leaf fiber (PALF) characteristics. The PALF was collected from the Subang plantation (Indonesia). The chemical treatment was carried out with pre-treatment using an alkalization process for 3 hours, and the oxidation process was carried out with TEMPO. TiO2 nanoparticle grafting was carried out …

Computational Fluid Dynamics Analysis Of Temperature Distribution In Solar Distillation Panel With Various Flat Plate Materials, Trismawati Trismawati, Hendry Y. Nanlohy, Helen Riupassa, Susi Marianingsih

Journal of Mechanical Engineering Science and Technology (JMEST)

As the world population continues to grow, the demand for clean water is increasing daily, making it a crucial resource to access. However, there are ways to harness abundant resources like solar energy and seawater to produce clean water. The present studies have conducted experimental investigations to convert seawater into freshwater using solar stills, where solar energy is utilized as the primary heat source for evaporation. The temperature distribution inside the solar stills was analyzed using a flat plate made of three different materials: copper, stainless steel, and aluminum. To examine the temperature distribution and performance of the solar stills, …

Comparative Analysis Of The Effect Dual Spark Ignition And Single Spark Ignition On Performance And Exhaust Emissions In Bioethanol-Fueled Engines, Avita Ayu Permanasari, Ahmad Faizal Wahidin, Hasan Ismail, Erwin Komara, Poppy Puspitasari, Gina A. Lorenzo

Journal of Mechanical Engineering Science and Technology (JMEST)

Bioethanol is an alternative fuel that has a high octane value of around 100 to 110, making it difficult to be applied to spark ignition engines directly. So, it is necessary to make adjustments, including increasing combustion efficiency and thermal efficiency of the combustion chamber by increasing the compression ratio and adjusting the ignition system, both in single spark ignition (SSI) and dual spark ignition (DSI) types. The study aims to determine the effect of SSI and DSI applications on engine performance, specific fuel consumption (SFC), and exhaust emissions using 96% and 99% levels of bioethanol fuel. The results showed …

Performance Enhancement Of Dye Sensitized Solar Cell (Dssc) Through Tio2/Rgo Hybrid: Comprehensive Study On Synthesis And Characterization, Rustan Hatib, Khairil Anwar, Ramang Magga, Muh Anjas Astak, Denny Widhiyanuriyawan, Wardoyo Wardoyo

Journal of Mechanical Engineering Science and Technology (JMEST)

The TiO2 film is immersed in a graphite oxide solution, preparing it for thermal reduction, which converts the graphite oxide to reduced graphene oxide (rGO). This process produces rGO hybrid TiO2 photoanodes for dye-sensitized solar cells (DSSC). rGO in the TiO2 structure prevents electron recombination and improves overall efficiency. The main advantage of this method is its ability to prevent loss of rGO during the sintering process, which is a common problem with other methods. The study investigated heating temperatures ranging between 300˚C, 350˚C, 400˚C, 450˚C, and 500˚C to determine optimal conditions. The presence of rGO in the photoanode structure …

Pyrolysis Kinetics Of Spirulina Platensis And Non-Condensable Gas Product Distribution In A Fixed-Bed Reactor, Ahmad Yusril Aminullah, Sukarni Sukarni, Retno Wulandari, Muhammad Shahbaz

Journal of Mechanical Engineering Science and Technology (JMEST)

Energy is a fundamental factor for civilization development and sustainability. However, energy sources are dominated by non-renewable fractions, such as fossil fuels. Renewable biomass is projected to be a future fuel source. Spirulina platensis (SP) has numerous advantages compared to other biomass, and it is considered 3rd generation biomass that does not interfere with food and land usage and has a relatively low main decomposition temperature at 325.7℃. Thermogravimetric analysis (TGA) was conducted to observe SP kinetics parameters, especially activation energy. Kissinger-Akahira-Sunose (KAS), Ozawa-Flynn-Wall (OFW), and Starink iso-conversional methods reveal that SP has an activation energy of 152.33, 154.56, and …