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Full-Text Articles in Engineering
The Advancement Of Experimental And Computation Tools For The Study Of Molten Salt Chemistry To Facilitate The Extraction Of Strategic Elements In Nuclear Applications, Michael Stoddard
Theses and Dissertations
Nuclear energy presents environmental benefits, yet the challenge of radioactive waste management persists. Advanced solutions, such as Molten Salt Reactors (MSRs), require a more profound understanding of molten salt chemistry. This research aims to develop tools, including a depletion simulator, molten salt electrochemical simulator, and a fluoride-based thermodynamic reference electrode for electrochemical purification. The computationally inexpensive depletion simulator allows for exploration into extraction and processing strategies for molten salt reactors. An illustrative case study on Mo-99 production from MSRs demonstrates the practical application of the theoretical framework, emphasizing the need for optimization in extraction effectiveness and separation difficulty. The electrochemical …
Developing An Accurate Simulation Model For Predicting Friction Stir Welding Processes In 2219 Aluminum Alloy, Kennen Brooks
Developing An Accurate Simulation Model For Predicting Friction Stir Welding Processes In 2219 Aluminum Alloy, Kennen Brooks
Theses and Dissertations
Modeling of friction stir welding (FSW) is challenging, as there are large gradients in both strain rate and temperature that must be accounted for in the constitutive law of the material being joined. Constitutive laws are most often calibrated using flow stresses from hot compression or hot torsion testing, where strain rates are much lower than those of the FSW process. As such, the current work employed a recently developed method to measure flow stresses in AA 2219-T67 at the high strain rates typical of FSW. These data were used in the development of a finite element simulation of FSW …
Simulation And Localization Of Autonomous Underwater Vehicles Leveraging Lie Group Structure, Easton Robert Potokar
Simulation And Localization Of Autonomous Underwater Vehicles Leveraging Lie Group Structure, Easton Robert Potokar
Theses and Dissertations
Autonomous underwater vehicles (AUVs) have the potential to dramatically improve safety, quality of life and general scientific knowledge. Our coasts, lakes and rivers are filled with various forms of marine infrastructure including dams, bridges, ship hulls, communication lines, and oil rigs. Each of these structures requires regular inspection, and current methods utilize divers, which is dangerous, expensive, and time consuming. AUVs have the potential to alleviate these difficulties and enable more regular inspection of these structures. Furthermore, there are significant scientific discoveries in the fields of geology, marine biology and medicine that AUV exploration of our oceans will enable. Since …
Modeling The Effects Of Parameter Changes On Heating And Pressure At The Weld Interface And Joint Strength In Friction Bit Joining, Adam Hartly Wagner
Modeling The Effects Of Parameter Changes On Heating And Pressure At The Weld Interface And Joint Strength In Friction Bit Joining, Adam Hartly Wagner
Theses and Dissertations
Joining of dissimilar metals is a process that is of interest in many fields, especially the automotive industry where lightweighting of the body structure is important. However, creating strong joints between dissimilar metals can be challenging. Friction bit joining (FBJ) is a solid-state method that uses a consumable bit to create a strong joint between dissimilar metals such as aluminum and steel. The purpose of this research is to gain understanding of how adjusting FBJ parameters affects the heating and pressure at the weld interface using a modeling approach, in order to better understand the bonding process. The questions guiding …
Molecular Dynamic Simulation Of Protein Devices And The Parameterization Of Azides And Alkynes For Use In Unnatural Amino Acid Models, Addison Kyle Smith
Molecular Dynamic Simulation Of Protein Devices And The Parameterization Of Azides And Alkynes For Use In Unnatural Amino Acid Models, Addison Kyle Smith
Theses and Dissertations
Proteins that have been modified by attaching them to a surface or to a polyethylene glycol (PEG) molecule can see many uses in therapeutics and diagnostics -- these unique proteins are called protein devices. Current techniques can perform these functionalizations at a specific residue on the protein, but what remains is identifying what happens to protein structure when mutated, and where to perform the attachment. Both of these issues can be examined using molecular dynamic (MD) simulations. Currently, simulations of the unnatural amino acid (uAA) mutations necessary for protein device functionalization cannot be executed, and full-protein screens of all possible …
Molecular Dynamic Simulation Of Protein Devices And The Parameterization Of Azides And Alkynes For Use In Unnatural Amino Acid Models, Addison Kyle Smith
Molecular Dynamic Simulation Of Protein Devices And The Parameterization Of Azides And Alkynes For Use In Unnatural Amino Acid Models, Addison Kyle Smith
Theses and Dissertations
Proteins that have been modified by attaching them to a surface or to a polyethylene glycol (PEG) molecule can see many uses in therapeutics and diagnostics -- these unique proteins are called protein devices. Current techniques can perform these functionalizations at a specific residue on the protein, but what remains is identifying what happens to protein structure when mutated, and where to perform the attachment. Both of these issues can be examined using molecular dynamic (MD) simulations. Currently, simulations of the unnatural amino acid (uAA) mutations necessary for protein device functionalization cannot be executed, and full-protein screens of all possible …
Improved Analysis Techniques For Scatterometer Wind Estimation, Gregory Dallin Schachterle
Improved Analysis Techniques For Scatterometer Wind Estimation, Gregory Dallin Schachterle
Theses and Dissertations
In this thesis, three improved analysis techniques for scatterometer wind estimation are presented. These techniques build upon previous methods that help validate scatterometer data. This thesis examines the theory connecting the 1D and 2D kinetic energy spectra and uses QuikSCAT data to measure the 2D kinetic energy spectrum of ocean winds. The measured 2D kinetic energy spectrum is compared to the traditional 1D kinetic energy spectrum. The relationship between the 2D kinetic energy spectra and the 1D kinetic energy spectra confirms findings from previous studies that ocean winds modeled in 2D are isotropic and nondivergent. The 1D and 2D kinetic …
The Programmatic Generation Of Discrete-Event Simulation Models From Production Tracking Data, Christopher Rand Smith
The Programmatic Generation Of Discrete-Event Simulation Models From Production Tracking Data, Christopher Rand Smith
Theses and Dissertations
Discrete-event simulation can be a useful tool in analyzing complex system dynamics in various industries. However, it is difficult for entry-level users of discrete-event simulation software to both collect the appropriate data to create a model and to actually generate the base-case simulation model. These difficulties decrease the usefulness of simulation software and limit its application in areas in which it could be potentially useful. This research proposes and evaluates a data collection and analysis methodology that would allow for the programmatic generation of simulation models using production tracking data. It uses data collected from a GPS device that follows …
Experimental And Numerical Study Of High-Speed Friction Stir Spot Welding Of Advanced High-Strength Steel, Utsab Karki
Experimental And Numerical Study Of High-Speed Friction Stir Spot Welding Of Advanced High-Strength Steel, Utsab Karki
Theses and Dissertations
With the desire to lighten the frame while keeping or increasing the strength, Advanced High-Strength Steels (AHSS) have been developed for use in the automotive industry. AHSS meet many vehicle functional requirements because of their excellent strength and acceptable ductility. But joining AHSS is a challenge, because weldability is lower than that of mild steels. Friction stir spot welding (FSSW) is a solid state joining process that can provide a solution to the weldability issues in AHSS, but FSSW has not been studied in great detail for this application. In this work, Si3N4 tools were used for FSSW experiments on …
Compressibility Measurement And Modeling To Optimize Flow Simulation Of Vacuum Infusion Processing For Composite Materials, Paul Hannibal
Compressibility Measurement And Modeling To Optimize Flow Simulation Of Vacuum Infusion Processing For Composite Materials, Paul Hannibal
Theses and Dissertations
Out-of-autoclave manufacturing processes for composite materials are increasing in importance for aerospace and automotive industries. Vacuum Infusion processes are leading the push to move out of the autoclave. An understanding of the various process parameters associated with resin infusion is necessary to produce quality product. Variance in compaction, resin, and vacuum pressures are studied, concentrating on developing a compaction pressure profile as it relates to fiber volume fraction. The purpose of this research is twofold: (1) to show and quantify the existence of a resin pressure gradient in compression testing using rigid tooling, and (2) to use measured test data …
Verifying Molecular Dynamics Using Dielectric Spectroscopy, Joshua Dee Smith
Verifying Molecular Dynamics Using Dielectric Spectroscopy, Joshua Dee Smith
Theses and Dissertations
The electrical properties of proteins in solution are important for their structure and function. Computational biophysics studies of proteins need accurate parameters to ensure that numerical simulations match physical reality. Past work in this eld has compared the electrical properties of proteins obtained from dielectric spectroscopy to numerical simulations of proteins in water with adjustment of pKa values to try to capture the inevitable changes in electrical conformation that will occur in a complex structure such as a folded protein. However, fundamental veri cation of the charge parameters of the amino acid building blocks in common molecular dynamics software packages …
Real-Time Visualization Of Finite Element Models Using Surrogate Modeling Methods, Ryan C. Heap
Real-Time Visualization Of Finite Element Models Using Surrogate Modeling Methods, Ryan C. Heap
Theses and Dissertations
Finite element analysis (FEA) software is used to obtain linear and non-linear solutions to one, two, and three-dimensional (3-D) geometric problems that will see a particular load and constraint case when put into service. Parametric FEA models are commonly used in iterative design processes in order to obtain an optimum model given a set of loads, constraints, objectives, and design parameters to vary. In some instances it is desirable for a designer to obtain some intuition about how changes in design parameters can affect the FEA solution of interest, before simply sending the model through the optimization loop. This could …
The Effects Of Mismatches And Probe Tethering Configurations On The Stability Of Dna Duplexes On Surfaces, Kyle Evan Pratt
The Effects Of Mismatches And Probe Tethering Configurations On The Stability Of Dna Duplexes On Surfaces, Kyle Evan Pratt
Theses and Dissertations
DNA microarrays are chip-based, analysis tools which can perform hundreds of thousands of parallel assays to determine the identity of genes or gene expression levels present in a sample. They have been identified as a key technology in genomic sciences and emergent medical techniques; however, despite their abundant use in research laboratories, microarrays have not been used in the clinical setting to the fullest potential due to the difficulty of obtaining reproducible results. Microarrays work on the principle of DNA hybridization, and can only be as accurate as this process is robust. Fundamental, molecular-level understanding of hybridization on surfaces is …
Protein-Surface Interactions With Coarse-Grain Simulation Methods, Shuai Wei
Protein-Surface Interactions With Coarse-Grain Simulation Methods, Shuai Wei
Theses and Dissertations
The interaction of proteins with surfaces is a major process involved in protein microarrays. Understanding protein-surface interactions is key to improving the performance of protein microarrays, but current understanding of the behavior of proteins on surfaces is lacking. Prevailing theories on the subject, which suggest that proteins should be stabilized when tethered to surfaces, do not explain the experimentally observed fact that proteins are often denatured on surfaces. This document outlines several studies done to develop a model which is capable of predicting the stabilization and destabilization of proteins tethered to surfaces. As the start point of the research, part …
Mathematical Model And Experimental Exploration Of The Nanoinjector Lance Array, Nathan C. Toone
Mathematical Model And Experimental Exploration Of The Nanoinjector Lance Array, Nathan C. Toone
Theses and Dissertations
The Nanoinjector Lance Array has been developed to inject foreign material into thousands of cells at once using electrophoresis to attract and repel particles to and from the electrically-charged lances. A mathematical computer model simulating the motion of attracted or repelled proteins informs the design of the nanoinjection lance array system. The model is validated by accurately predicting protein velocity in electrophoresis experiments. A complete analysis of parameters is conducted via simulations and specific research questions regarding the counter electrode of the nanoinjector lance array system are explored using the model. A novel technique for fabricating lance arrays from collapsed …
Multi-Processor Computation Of Thrombus Growth And Embolization In A Model Of Blood-Biomaterial Interaction Based On Fluid Dynamics, Brandon Thomas Andersen
Multi-Processor Computation Of Thrombus Growth And Embolization In A Model Of Blood-Biomaterial Interaction Based On Fluid Dynamics, Brandon Thomas Andersen
Theses and Dissertations
This work describes the development and testing of a real-time three-dimensional computational fluid dynamics simulation of thrombosis and embolization to be used in the design of blood-contacting devices. Features of the model include the adhesion and aggregation of blood platelets on device material surfaces, shear and chemical activation of blood platelets, and embolization of platelet aggregates due to shear forces. As thrombus develops, blood is diverted from its regular flow field. If shear forces on a thrombus are sufficient to overcome the strength of adhesion, the thrombus is dislodged from the wall. Development of the model included preparing thrombosis and …
A New Eulerian-Based Double Continuity Model For Predicting The Evolution Of Pair Correlation Statistics Under Large Plastic Deformations, Sadegh Ahmadi
Theses and Dissertations
A new model using a double-continuity relation for predicting the evolution of pair-correlation functions (PCFs) is presented. The proposed model was developed using statistical continuum theory and is employed to predict the viscoplastic behavior of polycrystalline materials. This model was built based upon the continuity relations and a double divergence law that guarantees the conservation of both orientation and mass; and also satisfies the field equations (equilibrium, constitutive, and compatibility) at every point of the polycrystalline material throughout the deformation process. In the presented model, motion of particles in the real space and rotation of crystallographic orientations in the Euler …
The Structure And Stability Of Alpha-Helical, Orthogonal-Bundle Proteins On Surfaces, Shuai Wei
The Structure And Stability Of Alpha-Helical, Orthogonal-Bundle Proteins On Surfaces, Shuai Wei
Theses and Dissertations
The interaction of proteins with surfaces is a major problem involved in protein microarrays. Understanding protein/surface interactions is key to improving the performance of protein microarrays, but current understanding of the behavior of proteins on surfaces is lacking. Prevailing theories on the subject, which suggest that proteins should be stabilized when tethered to surfaces, do not explain the experimentally observed fact that proteins are often denatured on surfaces. In an attempt to develop some predictive capabilities with respect to protein/surface interactions, it was asked in previous works if the stabilization/destabilization of proteins on surfaces could be correlated to secondary structure …
Development Of A Methodology For Numerical Simulation Of A D C Arc Discharge In A Liquid Dielectric, Christopher James Lewis
Development Of A Methodology For Numerical Simulation Of A D C Arc Discharge In A Liquid Dielectric, Christopher James Lewis
Theses and Dissertations
The majority of literature regarding the numerical simulation of arc discharges in gaseous environments has used a plasma physics approach. Virtually all simulations treat the discharge as an idealized gaseous plasma, which can be described by temperature, pressure, and electric field. This approach can work well if the media is a shielding gas such as Argon; however, the approach does not work well for processes such as underwater welding, EDM, and underwater discharges used to generate high purity particles. The reason these discharges do not have many extensive simulation efforts as described in the literature is because they occur in …
Prediction Of Fluid Viscosity Through Transient Molecular Dynamic Simulations, Jason Christopher Thomas
Prediction Of Fluid Viscosity Through Transient Molecular Dynamic Simulations, Jason Christopher Thomas
Theses and Dissertations
A novel method of calculating viscosity from molecular dynamics simulations is developed, benchmarked, and tested. The technique is a transient method which has the potential to reduce CPU requirements for many conditions. An initial sinusoidal velocity profile is overlaid upon the peculiar velocities of the individual molecules in an equilibrated simulation. The transient relaxation of this initial velocity profile is then compared to the corresponding analytical solution of the momentum equation by adjusting the viscosity-related parameters in the constitutive equation that relate the shear rate to the stress tensor. The newly developed Transient Molecular Dynamics (TMD) method was tested for …
Computer-Based Instruction For Engineering Education In The Developing World, Bradford G. Singley
Computer-Based Instruction For Engineering Education In The Developing World, Bradford G. Singley
Theses and Dissertations
Although civil engineers continually develop new ways to solve problems involving water, energy, infrastructure and environmental sustainability, these innovations can take years – or even decades – to reach developing countries. Computer-based instruction has the potential to dramatically decrease this lag time by improving engineering education in the developing world. This paper discusses the development of instructional simulations, based on the theory of model-centered instruction. These simulations can serve as self-paced learning modules, which can be accessed for free over the Internet. A pilot learning module was developed for the United Nations Educational Scientific and Cultural Organization (UNESCO) on the …
A New Method For Treating Wells In Reservoir Simulation, Gregory M. Gessel
A New Method For Treating Wells In Reservoir Simulation, Gregory M. Gessel
Theses and Dissertations
A new method for formulating finite difference equations for reservoir simulation has been developed. It can be applied throughout the entire simulated reservoir or to local segments. When applied to cells containing vertical, fully penetrating, straight-line wells in a homogeneous reservoir, the resulting equations are equivalent to Peaceman's classical well equations used in most reservoir simulators today. However, when the new finite difference equations are applied to both the well-containing cells, and their neighbors, the accuracy of the simulation improves substantially. The method produces still better accuracy results when applied throughout the reservoir. Unlike the Peaceman correction, the new method …
Integrating Value Stream Mapping And Simulation, Michelle E. Scullin
Integrating Value Stream Mapping And Simulation, Michelle E. Scullin
Theses and Dissertations
An important principle in Lean manufacturing, value stream mapping (VSM) can be helpful in understanding how process flow and information flow affect each other. A VSM is a static picture of a process that allows the user to see where value is added into the value stream. Simulation is used to evaluate the behavioral issues of processes. In a manufacturing realm this means simulation shows how each operation affects other operations so determinations can be made about where bottlenecks or other problems exist in the process. Theoretically, the integration of VSM and Simulation can aide in process improvement by showing …
A Flexible Infrastructure For Multi-Agent Systems, Gerrit Addison N Sorensen
A Flexible Infrastructure For Multi-Agent Systems, Gerrit Addison N Sorensen
Theses and Dissertations
Multi-Agent coordination and control has been studied for a long time, but has recently gained more interest because of technology improvements allowing smaller, more versatile robots and other types of agents. To facilitate multi-agent experiments between heterogeneous agents, including robots and UAVs, we have created a test-bed with both simulation and hardware capabilities. This thesis discusses the creation of this unique, versatile test-bed for multi-agent experiments, also a unique graph creation algorithm, and some experimental results obtained using the test-bed.
Development And Application Of A New Modeling Technique For Production Control Schemes In Manufacturing Systems, Bashar Hafez Sader
Development And Application Of A New Modeling Technique For Production Control Schemes In Manufacturing Systems, Bashar Hafez Sader
Theses and Dissertations
This dissertation presents dynamic system models of continuous manufacturing systems based on analogies with electrical systems. The developed modeling technique has the capability to explicitly specify production control schemes including control points, material and information flow paths, and logical operations. The model provides standard graphical representations and governing equations to describe both the steady state and transient responses of continuous manufacturing systems. For deterministic systems, these equations can be solved to get closed-form solutions. For stochastic systems, numerical solutions can be obtained for any probabilistic distribution. The electrical analogs provide an excellent tool to model control signals and logical operations. …
A Tool Wear Comparative Study In Turning Versus Computer Simulation In 1018 Steel, Woodrow D. Miner
A Tool Wear Comparative Study In Turning Versus Computer Simulation In 1018 Steel, Woodrow D. Miner
Theses and Dissertations
The material removal process uses cutting tools in order to produce the desired shape of the workpiece. Tool wear has been a problem for cutting tools, since cutting tools wear and break. Research has been accomplished in the tool wear field for tool life and more recently tool wear. The computer generation has created a method to simulate the material removal process. These computer simulations model the cutting tool reaction with the workpiece. Many of the simulation models use finite element analysis to calculate the reaction of the cutting tool. Different finite element models are being used throughout the world …
A Finite Element Simulation Of Temperature And Material Flow In Fricton Stir Welding, Mark J. Lasley
A Finite Element Simulation Of Temperature And Material Flow In Fricton Stir Welding, Mark J. Lasley
Theses and Dissertations
The purpose of this research was to use the Transvalor S.A. product, Forge3, to develop a finite element simulation of the friction stir welding process that improves the predictability of temperature evolution and material flow within the plunge portion of the process. Previous modeling created more heating within the billet than experimental results, probably due to the simplification of the simulation with adiabatic boundary conditions. More realistic tooling temperatures were included in this model as these affect heat evolution which is a determining factor in microcrystalline growth. These results were validated by experimental efforts using a billet and tooling instrumented …
The Benefit Of Using Simulation To Improve The Implementation Of Lean Manufacturing Case Study: Quick Changeovers To Allow Level Loading Of The Assembly Line, Jack J. Mcclellan
The Benefit Of Using Simulation To Improve The Implementation Of Lean Manufacturing Case Study: Quick Changeovers To Allow Level Loading Of The Assembly Line, Jack J. Mcclellan
Theses and Dissertations
In today's competitive manufacturing environment, companies are constantly looking for ways to improve. Because of this, many companies are striving to become "lean" by implementing lean manufacturing, which is a difficult process. To aid in the implementation of lean manufacturing, simulation was used to reduce the trial-and-error period of lean manufacturing and find to optimum approach to implement the lean manufacturing principle. In this research, a case study of implementing level loading of the production schedule for BullFrog International, L.C. will be examined. To make it possible to implement level loading, the thermo-former machine at the beginning of the operations …
The Use Of Two Mixture Fractions To Treat Coal Combustion Products In Turbulent Pulverized-Coal Flames, Daniel V. Flores, Thomas H. Fletcher
The Use Of Two Mixture Fractions To Treat Coal Combustion Products In Turbulent Pulverized-Coal Flames, Daniel V. Flores, Thomas H. Fletcher
Faculty Publications
Previous coal combustion models using assumed-shape PDF's to treat turbulence-chemistry interactions have used only one progress variable to treat products from coal reactions. This assumes that the products of all coal reactions have the same composition. However. the composition of the combustion products of coal particles is known to vary with burnout, especially between devclatilization and char oxidation. In this work, two progress variables were implemented which distinguish between the products of devolatilization and those of char oxidation. This new approach requires as input the specified volatile content and elemental release during devolatilization. The values for these parameters were estimated …