Mechanical Engineering Commons^™

High Temperature Strength Reduces Soldering In Aluminum High Pressure Die Casting, Jacob A. Belke

Dissertations, Master's Theses and Master's Reports

Die soldering, an adhesion defect in high pressure die casting (HPDC), is a symptom of localized sticking where a localized portion of the cast material is adhered to the tooling surface causing build up over time. This requires the tooling to be serviced which incurs additional costs to the process that gets passed on to the parts. Historically, soldering has been mitigated using lubricants, coatings, and alloy chemistry modifications but solder persists.

The Tresca friction thermomechanical model suggests soldering occurs when the local interfacial shear stress between the casting and die surface exceeds the local shear strength of the casting. …

Design, Testing And Neural Network Modeling Of A Low-Friction Wave Energy Converter Testbed, Vasu Bhardwaj

Dissertations, Master's Theses and Master's Reports

Point absorber wave energy converters (WECs) transform water wave kinetic energy into other useful forms, typically electrical. While it’s possible to extract energy from passive WECs, more energy can be captured using active control where its power take-off (PTO) acts as both a generator and an actuator. Control strategies usually require accurate models often obtained during model-scale testing. Unfortunately, friction can dominate the dynamic response in small WEC models. A frictionless point absorber WEC testbed is described in this report which allows the researcher to focus on fundamental hydrodynamic behavior instead of friction. It uses air bearings for vertical motion …

Study Of Nanoparticle Dispersed Phase Change Materials And The Impact Of Temperature Gradient On The Potential For Particle Migration, Udit Sharma

Dissertations, Master's Theses and Master's Reports

Supercooling in phase change materials (PCMs) and the associated challenges in enhancing thermal conductivity through nanoparticle dispersion prompted this investigation. Existing literature exhibits inconsistencies in thermal conductivity improvements, suggesting a potential correlation with nanoparticle migration induced by thermophoresis. To address this, a novel temperature-dependent scaling parameter, \(\xi\), was introduced to predict particle migration propensity. A strong association was observed between higher \(\xi\) values and diminished thermal conductivity enhancements, indicating a significant influence of nanoparticle movement on heat transfer.

To further elucidate this relationship, a Nanoparticle Interaction Parameter \(N_\text{{pl}}\) was developed, incorporating critical fluid properties and interfacial effects. The derived critical …

Nonlinear Hydrodynamic Modeling And Control Of Wave Energy Converters, Tania Demonte Gonzalez

Dissertations, Master's Theses and Master's Reports

The growing urgency to transition towards carbon-neutral energy sources has sparked significant interest in diversifying energy portfolios by incorporating renewable energies, including the untapped potential of wave energy. This dissertation sets its objectives in advancing wave energy converter (WEC) technologies by focusing on developing and validating a nonlinear modeling technique and designing control strategies to maximize energy extraction and enhance WEC efficiency. At the heart of this research is the derivation and validation of an algebraic nonlinear Froude-Krylov forces model. Building on this foundational model, a robust nonlinear sliding mode controller and a nonlinear model predictive controller are designed to …

An Elasto-Plastic Constitutive Model With Phase-Field Fracture For Additively Manufactured Metallic Materials, Nolan Ruble

Dissertations, Master's Theses and Master's Reports

The advent of additive manufacturing (AM), commonly known as 3D printing, has revolutionized the production of metallic components across various industries. This technology, which builds objects layer by layer, has shifted paradigms in manufacturing, allowing for unprecedented design freedom, material efficiency, and rapid prototyping. Metal additive manufacturing, in particular, has shown remarkable promise due to its ability to produce complex geometries that are difficult or impossible to achieve with traditional subtractive methods. In addition, additively manufactured (AM) materials are gaining popularity in thanks to their often superior and controllable properties in comparison to their wrought counterparts. In the present work, …

Modeling Pulsatile Flows Using Truly Incompressible Finite Volume Lattice Boltzmann Model, Akshay S. Dongre

Dissertations, Master's Theses and Master's Reports

The present study addresses the compressibility error inherent in the standard Lattice Boltzmann Method (LBM) and LBM’s restriction to uniform Cartesian meshes. To mitigate the compressibility error, an incompressible LBM (iLBM) model has been incorporated into the finite volume framework using a cell-centered finite volume approach, leveraging the simplicity of the LBM algorithm for irregularly shaped flow domains with unstructured meshes. Monotonic Upstream-centered Scheme for Conservation Laws (MUSCL) and linear reconstruction (LR) schemes have been used to compute convective fluxes across the cell interfaces with boundary conditions implemented using the second-order accurate Non-Equilibrium Extrapolation (NEE) method.

The finite volume iLBM …

Analysis Of Factors Affecting Engine Knock In Modern Spark Ignition Gasoline Engines To Improve Engine Efficiency, Siddharth Gopujkar

Dissertations, Master's Theses and Master's Reports

Spark ignition engine knock is an issue that has persisted for over a century. Knock prevents the spark in an SI engine to be deployed at the most optimum time in the engine cycle, which leads to a decrease in the efficiency of the engine. A reduction in the efficiency directly translates to increased emissions and fuel costs. This research looks at experimental works to analyze the impact of three separate factors on knock in an effort to minimize it and improve engine efficiency.

The first factor is fuel chemistry – how Research Octane Number (RON) and Motor Octane Number …

Phase Field Modeling Of Fracture And Phase Separation Using Numerical Methods And Machine Learning, Revanth Mattey

Dissertations, Master's Theses and Master's Reports

Phase field modeling is a crucial tool in scientific and engineering disciplines due to its ability to simulate complex phenomena like phase transitions, interface dynamics, and pattern formation. It plays a vital role in understanding material behavior during processes such as solidification, phase separation, and fracture mechanics. Particularly in fracture mechanics, phase field modeling can be utilized to predict the crack path in complex materials. Understanding the failure behavior is vital for applications of any material. The specific contributions to the field of phase field fracture mechanics, are, Firstly, we propose a novel phase field fracture model to simulate the …

Comprehensive Review And Development Of A High-Pressure Hydraulic Impedance Tube For Vibroacoustic Attenuator Characterization, Matthew D. Beals

Dissertations, Master's Theses and Master's Reports

This research establishes a versatile test bench for characterizing hydraulic vibroacoustic attenuators. The primary evaluation metric is the transfer matrix, determined experimentally, with an emphasis on key properties such as transmission loss. To ensure accuracy and broad applicability, the methodology is based on industry-standard techniques for determining the transfer matrix. A comprehensive literature review consolidates existing approaches for hydraulic attenuator characterization. The test bench features a hydraulic impedance tube equipped with eight dynamic pressure transducer (DPT) taps strategically positioned before and after the sample interface. This setup accommodates arbitrary samples terminated with standard hydraulic fittings. Using ASTM E2611, the transfer …

Data To Physics: Bridging Modeling Frameworks For Metastructures, Hrishikesh Suhas Gosavi

Dissertations, Master's Theses and Master's Reports

The effective attenuation of wave propagation in specific frequency ranges, known as bandgaps, makes metastructures valuable in various engineering applications. Traditionally, bandgap estimation has relied on physics-based models, which present challenges for complex metastructures where accurate material properties and geometric complexities make precise modeling difficult. This work introduces data-driven techniques for bandgap estimation, leveraging the dynamic behavior, particularly the Frequency Response Functions (FRFs) of unit cells, to calculate dispersion relations and couple unit cells through dynamic substructuring. This approach addresses the limitations of traditional methods by directly utilizing experimental data to characterize both longitudinal and flexural bandgaps.

To evaluate data-driven …

Assessment Of Surface Waviness In A Wire Arc Additive Manufacturing Process, Shammas Mahmood Shafi

Dissertations, Master's Theses and Master's Reports

Wire Arc Additive Manufacturing (WAAM) is increasingly recognized for its ability to produce metal components with high deposition rates and efficiency, particularly in the aerospace and automotive sectors. However, one significant challenge that WAAM faces is achieving surface quality that complies with industry standards, as well as creating geometries that closely resemble the initial design. A crucial factor contributing to this challenge is surface waviness, which is an inherent characteristic of the WAAM process. This waviness arises from the geometry of the weld beads and the overlap distance between them. It can adversely affect the fusion quality of successive layers, …

Investigation Of Operational Parameter Differences Between The Standard Ron Test Method And Knock-Limited Modern Spark-Ignition Engine Operation, Alexander Hoth

Dissertations, Master's Theses and Master's Reports

Octane numbers (ONs) are used worldwide to rate the knock propensity of gasoline-like fuels for spark-ignition engines, making ONs the leading indicator of fuel quality for commercial distribution. The ONs were established 90 years ago and have only received minor changes compared to significant advancements in modern engine operation and fuel composition. This has resulted in discrepancies between knock-limited modern engine operation and standard ON ratings. This dissertation used a standard CFR octane rating engine at Argonne National Laboratory that was instrumented with modern combustion research tools to investigate key differences between the Research Octane Number (RON) rating conditions and …

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 …

Borophene And Graphene For Non-Enzymatic Biosensor- Ab-Initio Study, Omar A. Ismail

Theses and Dissertations

Non-enzymatic glucose sensing holds promise to overcome limitations associated with glucose oxidase, such as oxygen dependence and short shelf life. This study explores the potential sensing capabilities of borophene and graphene through direct interaction with various compounds, including β-glucose, uric acid, ascorbic acid, fructose, and acetaminophen. Using Density Functional Theory (DFT), we calculated binding energies and the respective Density of States (DOS) for these adsorbates on both graphene and borophene surfaces. Preliminary results suggest that borophene might exhibit nearly twice the affinity for β-glucose compared to graphene. Moreover, the calculated Density of States reveals distinct distortions in the electronic states …

The Interaction Of The Cotton Piece With The Piles Of The Scrabble Cotton Drum, Fazliddin Egamberdiev, Ilkhom Abbazov, Oybek Kholmuratov, Rashid Kaldybaev

Technical science and innovation

This article presents the results of an analytical study of the process of loosening and cleaning raw cotton from small debris by pileging working bodies of purifiers, on the basis of which directions for further research were chosen to optimize the parameters of the developed pile drum with spherical piles and rubber strips. Cotton entering production contains impurities. The processes of loosening and cleaning the fiber shreds are key in the initial stages of ginning, as they prepare the raw cotton for ginning and directly affect the reliability, productivity of these processes and the quality of the resulting fiber. Weed …

Adaptation Algorithm For Self-Tuning Of Parameters Of Models Of Multi-Stage Flotation Processes, Nilufar Sharifzhanova, Maksadhan Yakubov, Francesco Gregoretti

Technical science and innovation

Modern methods for solving problems of planning the execution of batches of tasks in multi-stage systems are characterized by the presence of restrictions on their dimensionality, the impossibility of guaranteed obtaining better results in comparison with fixed packages for different values of the input parameters of the problem. In the article, the author solved the problem of optimizing the composition of job packages running in multi-stage systems using the branch and bound method. Research has been carried out on various ways to form package execution orders tasks in multi-stage systems (heuristic rules for ordering packages tasks in the sequence of …

An Experimental Investigation Of The New Vibration Viscometer, Jamshidbek Ulugbek Ugli Shamuratov

Technical science and innovation

The characteristics of the new oscillating-plate viscometer have been investigated experimentally. The results obtained are as follows: the resonant frequency of plate oscillation decreases with increasing viscosity; the apparatus constant 𝐾 determined experimentally includes the end and slip effects; the dimensions of the plate should be determined by referring to empirical relations between 𝜌𝜇 and Λ(≡{(𝐸𝑎𝐸)−1}𝑛) for various dimensions of the plate; where 𝜌 is the density, 𝜇 is the viscosity; 𝐸𝑎 the resonant amplitude of plate in the air; E the amplitude of plate in a liquid, and 𝑛 a constant. If the distance between the plate and the …

Indicators Affecting Passenger Service Processes And Their Scientific Interpretation, Maxliyoxon Madaminova Maxamatjon Qizi, Saidazim Amanullayevich Ganihodjayev

Technical science and innovation

Many traffic flow parameters affect the performance of the road network at high voltage. These are low vehicle speeds, high vehicle distances relative to road capacity, and density per unit time (lane occupancy). In turn, a number of factors affect the decrease in traffic speed: the presence of slow-moving vehicles in the stream; pedestrians crossing the road irregularly; increase in traffic flow, etc. The issues of public transportation depend on many factors, each of which requires a separate approach and a complex solution. In large cities around the world, the quality indicators of public transport services, including the issues of …

Programming A Numerical Model Of Spherical Propagation Of Electric Discharge In Liquid, Mukhiddin Kushshaevich Khudjaev

Technical science and innovation

The subject of research is the determination of the hydrodynamic parameters of a liquid in the process of an electric discharge in a liquid. A numerical algorithm was constructed and a program was drawn up to determine the hydrodynamic parameters of a liquid in the process of an electric discharge in a liquid for a spherical problem. In the numerical solution of the problem, a uniform rectangular grid was used. Some results of computational experiments are presented.

Multi-Mode Regulation Of The Drying Process Of Industrial Gas, Isamidin Xakimovich Sidikov Pr, Nashvandova Gulruxsor Murot Qizi Phd

Technical science and innovation

Currently, much attention is paid to the issue of energy efficiency of gas processing enterprises. The continuous growth of world prices for energy resources requires constant improvement of the management system, providing the most optimal conditions for the flow of technological processes. A conceptual model of the heat-mass transfer process occurring in the absorber as an object of research has been developed, which characterizes the relationship of the variables involved in the drying process of natural gas, control, measurable and immeasurable, as well as controlled parameters have been selected, which are used to develop and study a mathematical model of …

Reducing Food Scarcity: The Benefits Of Urban Farming, S.A. Claudell, Emilio Mejia

Journal of Nonprofit Innovation

Urban farming can enhance the lives of communities and help reduce food scarcity. This paper presents a conceptual prototype of an efficient urban farming community that can be scaled for a single apartment building or an entire community across all global geoeconomics regions, including densely populated cities and rural, developing towns and communities. When deployed in coordination with smart crop choices, local farm support, and efficient transportation then the result isn’t just sustainability, but also increasing fresh produce accessibility, optimizing nutritional value, eliminating the use of ‘forever chemicals’, reducing transportation costs, and fostering global environmental benefits.

Imagine Doris, who is …

Rans-Dns Simulations For Uncertainty Quantification In Dns Data Of Turbulent Mixing Layer, Mohamed Abuhegazy

Mechanical Engineering ETDs

Mixing layer flow is one of the canonical free shear flows in fluid dynamics. Such a flow is formed when two fluid streams move along one another with different velocities. Investigation of this flow development has been an active topic of research for many decades not only due to a wide range of environmental and technological applications where this flow may be observed, but also because of large discrepancies in the results obtained experimentally and numerically regardless this flow simple geometry. In this dissertation, the quality and uncertainty of extracted turbulent statistics of mixing layer flow are analyzed by applying …

Fabrication & Characterization Of Hybrid Piezoelectric/Triboelectric Nanocomposite Nanogenerators Via Fusion Deposition Modeling, Khaled El Toukhy

Theses and Dissertations

This thesis aims to discuss the potential of using piezoelectric and triboelectric nanogenerators (PTENGs) for energy harvesting, particularly in the sportswear industry. PTENG's main advantage is that it offers good flexibility making it suitable for high-strain applications. The piezoelectric effect is induced by embedding piezoelectric nanofillers into one of the two triboelectric layers. PTENGs can generate both piezoelectric and triboelectric signals when strained resulting in an enhanced output compared to regular piezoelectric nanogenerators (PENGs) and triboelectric nanogenerators (TENGs). TPU was adopted as the matrix for PTENGs advantageous due to their flexibility, low electrical resistivity, and compatibility with additive manufacturing techniques. …

Design Optimization Of The Lift Mechanism In The Robotic Walking Training Device Using The Engineering Design Methodology, Austin Bourgeois, Brian Rice, Chung-Hyun Goh

Mechanical Engineering Faculty Publications and Presentations

Partial paralysis caused by spinal cord injury (SCI) or stroke are two of the most prevalent forms of physical disability. Through proper gait training, people with incomplete SCI have more potential to retain or regain the ability to walk than those with complete SCI. To help patients who have these disabilities regain the function of walking unassisted, the robotic walking training device (RWTD) has been developed to perform gait rehabilitation. This research plays a pivotal role in advancing medical robotic technology and gait rehabilitation by conducting a comprehensive evaluation and comparison of three lift mechanisms. Specifically, the lift mechanisms are …

Combined Risk Based Inspection And Fault Tree Analysis For Repetitive 3-Phase Line Piping Leakage At West Java Offshore Topside Facility, Dona Yuliati, Akhmad Herman Yuwono, D. Rizal Asral, Donanta Dhaneswara

Journal of Materials Exploration and Findings

Hydrocarbon releases might result in serious consequences in various aspects. In addition to the contribution to environmental pollution, repetitive leakages need high repair costs. This study aim is to minimize potential repetitive leakage for other typical 3-phase piping systems. We conducted the risk assessment by adopting Risk Based Inspection (RBI) API 581 to identify risk level, calculating piping lifetime, recommended inspection plan and mitigations. The most relevant root causes can be obtained through quantitative Fault Tree Analysis (FTA). Observation and investigation was taken from eight 3-phase piping systems that experienced repetitive leakages. It has been found that the risk level …

The Effect Of Parameters In Cryogenic Treatment On Mechanical Properties Of Tool Steel: A Review, Ronaldus Caesariano Ekaputra, Myrna Ariati Mochtar

Journal of Materials Exploration and Findings

Tool steel is classified as special alloy steel which proposed as dies or mold materials as their high mechanical properties and dimensional stability. In order to improve tool steel’s mechanical properties, heat treatment process, especially, cryogenic treatment is conducted. Cryogenic treatment is done by exposing tool steel material at sub-zero liquid/gas media after heated at austenite temperature. This process significantly affects the martensite phase transformation increase and avoids retained austenite emersion. In particular, the higher martensite volume fraction, the higher hardness and wear resistance value of tool steel. It had been proven that adjusting critical process parameters of cryogenic treatment …

Nitrogen Gas Quenching Pressure Effect On Bs S155 Alloy Steel In Vacuum Furnace, Agus Mulyadi Hasanudin, Eddy Sumarno Siradj

Journal of Materials Exploration and Findings

The production of metal and alloy products requires the use of heat treatment, when during the heat treatment process, quenching is a crucial step. The quenching medium can be anything from water, a salt bath, oil, air and gas. In a vacuum furnace, pressurized gas, most frequently nitrogen (N₂) gas, serves as one of the quenching mediums. One of the drawbacks of the quenching process is the distortion and dimensional change of the parts. This paper aims to investigate the influence of nitrogen gas quenching pressure on the distortion and dimensional change of aerospace actuator gear planet parts …

Pipeline Risk Analysis Optimization With Monte Carlo Method Using Gamma Distribution, Farhan Rama Digita, Jaka Fajar Fatriansyah, Abdul Rahim Ridzuan, Hanna Ovelia, Imam Abdillah Mas'ud, Irma Hartia Tihara, Baiq Diffa Pakarti Linuwih

Journal of Materials Exploration and Findings

The inspection process of piping components in the oil and gas industry is one of the most crucial things, given the high risk posed by pipeline system failures, which have a huge impact on losses, both from environmental and financial aspects. Risk-based inspection with the Monte Carlo method is one of the efforts that can be made to minimize failures in piping systems, by involving data distribution to calculate the probability of component failure. Although the normal distribution is commonly used for generating random variables, its use in corrosion rate calculation can lead to overestimation due to negative corrosion rate …

Briquette Of Empty Fruit Bunch Fiber As An Alternative Substitution For Binderless Fuel Methods, Nofriady Handra, Ade Indra

Makara Journal of Technology

Biomass development has been a key issue for the past few decades and will remain attractive in the future because of its cleanliness, renewability, carbon neutrality, and other advantages. This study aims to determine the optimal holding time for heating system briquettes by testing the heating value of empty fruit bunches fibers. The process of this research involves the use of one unit of briquette molding equipment by providing a heating system to the mold cylinder. Fibers were manually finetuned until they reached a size of 20 mesh (0.84 mm). Densification temperature is an essential factor that could affect the …

Heat Transfer Enhancement In Nanofluid Flows Augmented By Magnetic Flux, Kozhikkatil Sunil Arjun, Rakesh Kumar

Makara Journal of Technology

Heat transfer enhancement could be realized using magnetohydrodynamics together with nanofluids specifically in flow micro-convection in a microtube, flow past a vertical porous plate, and square duct flow with discrete heat sources numerically. A critical value for the Rayleigh number, a maximum value for the magnetic field strength, a low Reynolds number, and volume concentrations exists for thermal enhancement to simulate nanofluid flow in a microtube. Heat transfer enhancement is observed with a reduction in the magnetic field strength in a flow past a heated porous vertical plate. Alumina nanofluid subjected to Hartmann number 10 can boost 81% enhancement in …