Physics Commons^™

Computational Design Of Complex Concentrated Alloys, Hamid Sharifi

Doctoral Dissertations

A high-throughput parameterization of modified embedded atom model (MEAM) interatomic potentials for combinations of Cu, Ti, Ni, Cr, Co, Al, Fe, and Mn was carried out using a genetic algorithm. Unary systems were parameterized based on DFT calculations and experimental results. MEAM potentials for 28 binary and 56 ternary combinations of the elements were parameterized to DFT results that were carried out with semi-automated frameworks. Specific attention was made to reproduce properties that impact compositional segregation, material strength, and mechanics. Utilizing the MEAM interatomic potentials and a Monte Carlo scheme, phase segregation in the CrNiCo, CuNiCr and CuNiCo fcc alloys …

Implementing Reactivity In Molecular Dynamics Simulations With Harmonic Force Fields, Jordan J. Winetrout, Krishan Kanhaiya, Josh Kemppainen, Pieter J. In ‘T Veld, Geeta Sachdeva, Ravindra Pandey, Behzad Damirchi, Adri Van Duin, Gregory Odegard, Hendrik Heinz

Michigan Tech Publications

The simulation of chemical reactions and mechanical properties including failure from atoms to the micrometer scale remains a longstanding challenge in chemistry and materials science. Bottlenecks include computational feasibility, reliability, and cost. We introduce a method for reactive molecular dynamics simulations using a clean replacement of non-reactive classical harmonic bond potentials with reactive, energy-conserving Morse potentials, called the Reactive INTERFACE Force Field (IFF-R). IFF-R is compatible with force fields for organic and inorganic compounds such as IFF, CHARMM, PCFF, OPLS-AA, and AMBER. Bond dissociation is enabled by three interpretable Morse parameters per bond type and zero energy upon disconnect. Use …

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 …

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 …

Activity: Students Find Conceptual Errors In Ai Output, Janie Brennan

Generative AI Teaching Activities

Instructor asks ChatGPT questions related to a key concept to find one where ChatGPT has conceptual errors. Ask students to find the errors and explain them.

Lunar: Automated Input Generation And Analysis For Reactive Lammps Simulations, Josh Kemppainen, Jacob R. Gissinger, S. Gowtham, Gregory Odegard

Michigan Tech Publications

Generating simulation-ready molecular models for the LAMMPS molecular dynamics (MD) simulation software package is a difficult task and impedes the more widespread and efficient use of MD in materials design and development. Fixed-bond force fields generally require manual assignment of atom types, bonded interactions, charges, and simulation domain sizes. A new LAMMPS pre- and postprocessing toolkit (LUNAR) is presented that efficiently builds molecular systems for LAMMPS. LUNAR automatically assigns atom types, generates bonded interactions, assigns charges, and provides initial configuration methods to generate large molecular systems. LUNAR can also incorporate chemical reactivity into simulations by facilitating the use of the …

Settingsorder Article Reprints Open Accesseditor’S Choicearticle Exploring The Impact Of Spray Process Parameters On Graphite Coatings: Morphology, Thickness, And Tribological Properties, Adedoyin Abe, Josue A. Goss, Min Zou

Mechanical Engineering Faculty Publications and Presentations

This study explores, through a full factorial experimental design, the effects of graphite concentration and spray flow rate on the morphology, thickness, and tribological performance of graphite coatings for potential tribological applications. Coatings were applied to rough substrates using varying concentrations and flow rates, followed by analysis of their morphological characteristics, roughness, thickness, coefficient of friction (COF), and wear behavior. The results revealed distinct differences in the coating morphology based on flow rate, with low-flow-rate coatings exhibiting a porous structure and higher roughness, while high-flow-rate coatings displayed denser structures with lower roughness. A COF as low as 0.09 was achieved, …

Focused Led Sintering, Dylan Defazio, Nilav Maulik, Branden Majors, Michael Fontillas

Mechanical Engineering

This report provides a detailed overview of the final design of our light-emitting diode (LED) focusing system. Our system incorporates a converging lens and a specially designed "glass funnel," which acts as a thick fiber optic that narrows the light to a fine point through internal reflection. The glass components of our system are precisely housed in a part made using advanced computer-numeric controlled (CNC) Mill and CNC Lathe manufacturing processes. This ensures high precision and durability of the overall system. Our LED focusing system is designed with a 60-watt stage light. The decision to use a glass funnel as …

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 …

Effects Of Ti Addition On The Characteristics Of Al-10zn-6mg-2si/Zro2 Composites Produced By Squeeze Casting, Qesha Diva Prameshvara, Pipin Indah Lestari, Bondan Tiara Sofyan

Journal of Materials Exploration and Findings

Metal matrix composite (MMC) with 7xxx aluminum matrix is potential for ballistic applications due to the combination of strength, toughness, and light weight. Previous study successfully produced aluminum-based composites with SiC particles which were able to stop type III bullet, however cracks remained on back of the plate. Therefore, in this research, SiC was replaced by zirconia (ZrO₂) due to its high fracture toughness. Ti-B grain refiner was added to further improve toughness through grain boundary strengthening mechanism. This research developed 5 vol.% ZrO₂ strengthened Al-10Zn-6Mg-2Si composite with addition of Al-5Ti-1B grain refiner produced through squeeze casting …

Integration Of The Ashby Technique And Pahl-Beitz Quantitative Ranking For Railway Axle Material Selection, Helya Chafshoh Nafisah, Jaka Fajar Fatriansyah, Siti Norasmah Surip

Journal of Materials Exploration and Findings

Railway axle serves as a vital connection between the train's wheels and its body. However, cyclic loading and high speed can induce fatigue in railway axle, which potentially leads to damage human safety. Therefore, it is important to find materials that have good mechanical properties with the lowest weight and cost. In this paper, a comprehensive method using Ashby chart has been performed to select candidate materials of railway axle. The methods begin with analyzing function by determining the problem, objective function, and constraints. After that, the results obtained are ranked using Pahl and Beitz quantitative weighting method. The results …

Analysis Of The Effect Of Different Surface Preparation Methods On Corrosion Resistance And Adhesion Strength Of Astm A36 Steel Substrate With Surface Tolerant Epoxy Paint As Coating Material, Irwan Wijaya Santoso, Daffa Aqila, Rini Riastuti, Rizal Tresna Ramadhani

Journal of Materials Exploration and Findings

In the industrial world, to extend the service life of materials, protection methods are carried out to slow down the material's corrosion rate. The protection method that is often used is the coating method. The coating method is a protection method by coating the substrate material using a coating material to prevent contact between the substrate material and the environment. In this research, the substrate material used is ASTM A36 steel and the coating material used is Surface Tolerant Epoxy paint. The independent variable used in this study lies in the surface preparation method which consists of: solvent cleaning, hand …

The Analysis Of Mechanical Exfoliation Of Graphene For Various Fabrication And Automation Techniques, Lance Yarbrough

Physics Undergraduate Honors Theses

Mechanical Exfoliation

Blade Design And Validation Of Hydrokinetic Turbine To Harvest Water Current Energy, Setare Sadeqi

LSU New Orleans Theses and Dissertations

The innovative aspect of this research lies in the careful integration of cutting-edge technologies throughout the entire process of designing, fabricating, and testing the carbon fiber propeller for the 3-bladed horizontal axis ocean current turbine (OCT). SolidWorks software played a pivotal role in the initial design phase, enabling a meticulous and precise modeling of the propeller's geometry. The utilization of SolidWorks allowed for a detailed exploration of various design parameters, ensuring that the propeller's structure and form were optimized for performance in ocean current conditions. Moving beyond the realm of virtual design, the choice of carbon fiber as the fabrication …

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

LSU 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 …

Numerical Simulation Of Laser Induced Elastic Waves In Response To Short And Ultrashort Laser Pulses., Alireza Zarei

All Dissertations

In an era of intensified market competition, the demand for cost-effective, high-quality, high-performance, and reliable products continues to rise. Meeting this demand necessitates the mass production of premium products through the integration of cutting-edge technologies and advanced materials while ensuring their integrity and safety. In this context, Nondestructive Testing (NDT) techniques emerge as indispensable tools for guaranteeing the integrity, reliability, and safety of products across diverse industries.

Various NDT techniques, including ultrasonic testing, computed tomography, thermography, and acoustic emissions, have long served as cornerstones for inspecting materials and structures. Among these, ultrasonic testing stands out as the most prevalent method, …

Drag Reduction In Channel Flow Configurations For Laminar And Turbulent Flow Past Superhydrophobic Surfaces, Henry Louis Ems

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

In this work, we present friction drag reduction in minichannel laminar flow past superhydrophobic metallic surfaces. Femtosecond laser surface processing (FLSP), a one-step scalable method, was used to create permanent microscale and nanoscale structures on 316 stainless steel plates. The resulting superhydrophilic plates were covered by tall (215 μm) or short (27 μm) structures. The FLSP plates were then transitioned to superhydrophobic by evaporative deposition of a fluorinated silane, a low surface energy coating. Using purified water, the friction factor was obtained by measuring pressure drop along a minichannel with a rectangular cross section for flow rates corresponding …

The Analysis Of Mechanical Exfoliation Of Graphene For Various Fabrication And Automation Techniques, Lance Yarbrough

Mechanical Engineering Undergraduate Honors Theses

Mechanical Exfoliation of Graphene is an often-overlooked portion of the fabrication of quantum devices, and to create more devices quickly, optimizing this process to generate better flakes is critical. In addition, it would be valuable to simulate test pulls quickly, to gain insight on flake quality of various materials and exfoliation conditions. Physical pulls of graphene at various temperatures, pull forces, and pull repetitions were analyzed and compared to the results of ANSYS simulations, solved for similar results. Using ANSYS’ ability to predict trends in exfoliations, flake thickness and coverage using stress and deflection analyses were investigated. Generally, both strongly …

Oscillations Of Capillary Surfaces With Volume And Edge Effects, Dingqian Ding

All Dissertations

Capillary surfaces are defined by an interface endowed with surface tension that is partially supported by a solid substrate and are susceptible to oscillations reflecting a balance between fluid inertia and the restorative force of surface tension. The wave dynamics strongly depend upon volume change within the domain and edge effects through the boundary conditions applied at the contact-line formed at the liquid-gas-solid interface, while the spatial wave structure conforms to the geometry of the capillary surface. This dissertation develops mathematical models to address these effects for several canonical capillary surfaces, which are organized into two parts that are focused …

Measuring Soot In A Novel Configuration For Diffusion Flames Fueled By Ethylene Doped With Iso-Dodecane, Christian Bjork

Honors Scholar Theses

Sustainable Aviation Fuels (SAFs) are seen as the path forward for decarbonizing hard-to-electrify sectors. Using SAFs over traditional fossil fuels abates carbon dioxide emissions but still may present soot emission problems. A milestone in the abatement of soot would be understating its formation mechanisms.

This study aims to quantify soot products resulting from an ethylene flame doped with iso-dodecane, a surrogate SAF component. The burner selected for the investigation is the novel Planar Mixing Layer Flame (PMLF) which allows the tracking of soot formation with the height above the burner (HAB) in a stable diffusion flame. A baseline ethylene-fueled flame …

Thermal Performance Investigation Of Thermoelectric Cooling System With Various Hot-Side Cooling Methods, Bowo Y. Prasetyo, Parisya P. Rosulindo, Fujen Wang

Makara Journal of Technology

Thermoelectric devices have been widely used in various applications, including cooling and power generation. The potential application of thermoelectric cooling systems has been studied. However, these systems still face challenges in achieving optimal performance compared with other cooling systems. Several factors, including the hot-side cooling method, influence the performance of thermoelectric systems. This study aimed to investigate the effects of different hot-side cooling methods on the thermoelectric performance and thermal behavior of thermoelectric cooling systems. The testing methods involved the combination of the thermoelectric module with five hot-side heat exchangers, including a square heatsink, a round heatsink, a two-pipe heat …

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 …

Development Of On-The-Fly Quasi-Steady State Approximation For Chemical Kinetics In Cfd, Abhinav Balamurugan

Doctoral Dissertations and Master's Theses

This study analyzes the feasibility of On-The-Fly Quasi-Steady-State Approximation (OTF-QSSA) application for solving chemical kinetics within Computational Fluid Dynamics (CFD) simulations, aiming to reduce the computational demand of detailed mechanisms. An algorithm that dynamically identifies and designates Quasi-Steady-State (QSS) species at specific grid locations and instances during the simulation was developed. With this information, our method pseudo-delays the advancement of concentrations for these QSS species—effectively setting their rate of concentration change to zero for a set number iteration before updating using the detailed mechanism and thereby omitting the computationally intensive processes typically required for their calculation during those skipped iteration. …

Application Of The Fokker-Planck Equation For Quantifying Initial Condition Uncertainty Of Reversible Dynamic Systems, Troy S. Newhart

Mechanical & Aerospace Engineering Theses & Dissertations

Characterizing the behavior of dynamic systems requires the inclusion of initial conditions to propagate behavior forward in time. More realistic representations of system behavior quantify uncertainty about the initial conditions to assess sensitivity, reliability, and other stochastic response parameters. In many engineering applications, the uncertain initial conditions may be unknown given a desired response. This research applies the Fokker-Planck equation to reversible dynamic systems of select multi-dimensional nonlinear differential equations as a means for predicting the uncertainty about initial conditions. An alternating directions implicit numerical scheme is used to numerically solve the Fokker-Planck equation for both forward and reversed equations …

Effects Of Electron Beam Irradiation On Crmnv And Crmntiv High Entropy Alloys: Nano-Mechanical, Structural, And Thermodynamic Perspectives, N. A. Sultana, Y. S. Mohammed, S. J. Pendleton, J. Vennekate, G. Ciovati, X. Li, H. Baumgart, A. A. Elmustafa

Mechanical & Aerospace Engineering Faculty Publications

Beam exit windows are crucial components of any particle accelerator as they provide an interface between the beamline vacuum and target material at atmospheric media. For high beam power machines, special materials and designs are required to withstand high radiation and mechanical loads, while minimizing energy loss during transition and maximizing window lifetime. This research investigates the impact of electron beam exposure to bulk CrMnV and CrMnTiV high entropy alloys (HEAs) with the primary goal of identifying suitable candidate materials for the design of robust and durable exit window settings. The selection criteria include intrinsic characteristics, power dissipation, and mechanical …

Dynamics Of A 3-D Inlet/Isolator Measured With Fast Pressure-Sensitive Paint, Andrew N. Bustard, Mark E. Noftz, Mitsugu Hasegawa, Hirotaka Sakaue, Joseph S. Jewell, Nicholas J. Bisek, Thomas J. Juliano

Publications

Fast pressure-sensitive paint (PSP) was applied to an inlet/isolator designed using the Osculating Internal Waverider Inlet with Parallel Streamlines (OIWPS) method. The dorsal isolator surface pressure was measured using anodized-aluminum PSP through transparent cast acrylic that makes up the ventral portion of the isolator. Temperature-sensitive paint was utilized to correct for the PSP’s temperature sensitivity. The model was tested under Mach 5.7 flow at Re = 8.5 ×106 /m and 10.2 ×106 /m in the AFOSR–Notre Dame Large Mach-6 Quiet Tunnel (ANDLM6QT) under conventional noise conditions. Flow phenomena, such as shocks originating in the inlet and flow separation at the …

Rf And Mechanical Design Of A 915 Mhz Srf Cavity For Conduction-Cooled Cryomodules, G. Ciovati, A. Castilla-Loeza, G. Cheng, J. Henry, J. Rathke, J. Vennekate, K. Harding, T. Schultheiss, J. Lewis

Physics Faculty Publications

Conduction-cooled SRF niobium cavities are being developed for use in compact, continuous-wave electron linear accelerators for a variety of industrial applications. A 915 MHz two-cell cavity has been designed to achieve an energy gain of 3.5 MeV. The design of the cell shape aims at minimizing the peak surface magnetic field. Field flatness is achieved by adjusting the length of the outer end half-cells. The higher-order mode analysis shows that absorbers are not required for a moderate beam current of 5 mA. One of the beam tubes has two side-ports for insertion of coaxial fundamental power couplers. The mechanical design …

The Discharge-Induced Polarity-Dependent Propagation Characteristics Of A Strong Shock Wave, Anna Markhotok

Physics Faculty Publications

The specifics of a shock wave propagation down a positive column of a DC discharge in molecular chemically inert gases has been investigated. It was shown that axial gradients caused by the imbalance in the charged particle momentum transfer to the gas molecules can be a reason for the shock velocity dependence on the electric field direction. In pure nitrogen gas, the calculated shock velocity difference of up to 13.5% is in good agreement with the 12% value obtained in the experiment. A returning gas flow organizing in the discharge as a possible mechanism for an extended shock structure and …

Parametrization Of Fluid Models For Electrical Breakdown Of Nitrogen At Atmospheric Pressure, Shirshak K. Dhali

Electrical & Computer Engineering Faculty Publications

In the transient phase of an atmospheric pressure discharge, the avalanche turns into a streamer discharge with time. Hydrodynamic fluid models are frequently used to describe the formation and propagation of streamers, where charge particle transport is dominated by the creation of space charge. The required electron transport data and rate coefficients for the fluid model are parameterized using the local mean energy approximation (LMEA) and the local field approximation (LFA). In atmospheric pressure applications, the excited species produced in the electrical discharge determine the subsequent conversion chemistry. We performed the fluid model simulation of streamers in nitrogen gas at …

Simulation Of Wave Propagation In Granular Particles Using A Discrete Element Model, Syed Tahmid Hussan

College of Graduate Studies: Theses & Dissertations

The understanding of Bender Element mechanism and utilization of Particle Flow Code (PFC) to simulate the seismic wave behavior is important to test the dynamic behavior of soil particles. Both discrete and finite element methods can be used to simulate wave behavior. However, Discrete Element Method (DEM) is mostly suitable, as the micro scaled soil particle cannot be fully considered as continuous specimen like a piece of rod or aluminum. Recently DEM has been widely used to study mechanical properties of soils at particle level considering the particles as balls. This study represents a comparative analysis of Voigt and Best …