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Controlling Phase Fractions Of 304l-Ss In Selective Laser Melting Using Cooling Rate, Eberechukwu Anthony Okoro

Masters Theses

"This study examines the thermal profile and the ferrite-austenite phase fractions upon heating and cooling of 304- stainless steel powder via Selective Laser Melting (SLM). Experiments were performed to validate the ABAQUS finite element model, while the phase transformation simulation was performed using MatCalc and ThermoCalc. A correlation between the thermo-mechanical changes in ABAQUS and the microstructural changes from MatCalc was obtained by matching their cooling rates. The result indicates that cooling rate has a significant effect on the phase fractions of FCC and BCC formed in 304L stainless steel via the SLM process. The results also indicate that for …

Cyber-Physical Security Of An Electric Microgrid, Prashanth Palaniswamy

Masters Theses

"Cyber-physical systems (CPSs) are physical systems that are controlled or monitored by computer-based systems. CPSs are a combination of computation, networking, and physical processes. As CPSs are a combination of various diverse components, they are vulnerable to several security threats. Moreover, there are many different security domains (not just high/low, nor necessarily hierarchical). This paper utilizes previously developed multiple security domain nondeducibility (MSDND) to uncover potential integrity vulnerabilities in an electric microgrid. Invariants are manually generated using the insights obtained through MSDND analysis and use linear regression to automate the generation of invariants. The vulnerabilities are then mitigated, to the …

Generalized Adaptive Variable Bit Truncation Model For Approximate Stochastic Computing, Keerthana Pamidimukkala

Masters Theses

"Stochastic computing as a computing paradigm is currently undergoing revival as the advancements in technology make it applicable especially in the wake of the need for higher computing power for emerging applications. Recent research in stochastic computing exploits the benefits of approximate computing, called Approximate Stochastic Computing (ASC), which further reduces the operational overhead in implementing stochastic circuits. A mathematical model is proposed to analyze the efficiency and error involved in ASC. Using this mathematical model, a new generalized adaptive method improving on ASC is proposed in the current thesis. The proposed method has been discussed with two possible implementation …

An Approach For Formal Analysis Of The Security Of A Water Treatment Testbed, Sai Sidharth Patlolla

Masters Theses

"This thesis focuses on securing critical infrastructures such as chemical plants, manufacturing units, and power generating plants against attacks that disrupt the information flow from one component to another. Such systems are controlled by an Industrial Control System (ICS) that includes controllers communicating with each other, and with physical sensors and actuators, using a communications network.

Traditional security models partition the security universe into two worlds, secure and insecure, but in the real world the partitions often overlap and information is leaked even through the physical observation which makes it much harder to analyze a Cyber physical system (CPS). To …

Fuel Burnup Simulation And Analysis Of The Missouri S&T Reactor, Joshua Hinkle Rhodes

Masters Theses

"The purpose of this work is to simulate the fuel burnup of the Missouri S&T Reactor. This work was accomplished using the Monte Carlo software MCNP. The primary core configurations of MSTR were modeled and the power history was used to determine the input parameters for the burnup simulation. These simulations were run to determine the burnup for each fuel element used in the core of MSTR.

With these simulations, the new predicted isotopic compositions were added into the model. New core configurations were determined, and the burnup corrected model was used to predict the excess reactivity and control rod …

Investigation Of The Information Provided By Light Touch For Balance Improvement In Humans, Anirudh Saini

Masters Theses

"This study investigates the information provided by Light Touch (LT) in improving human postural stability without mechanical assistance. Light Touch, an interaction force with a magnitude about 1 N, is known to improve postural stability in humans during quiet standing. However, the nature of the information from LT that helped improve balance is yet unknown. In this work, we hypothesized that LT provides information about one's body kinematics. We used a haptic robot to provide modulated, measurable light interaction force on the high back haptic location of humans to provide body kinematics-dependent information through LT. Standing balance experiments were performed …

Management Of Coal Dust Explosions In United States' Coal Mines Using Bag Type Passive Explosion Barriers, Jay Robert Schafler

Masters Theses

"The most significant and powerful hazard that exists in an underground coal mine is a coal dust explosion. A coal dust explosion has the potential to propagate throughout a mine resulting in massive damage to the mine and equipment, as well as tragic loss of life. An assessment of current global regulations and practices uncovered four main control methods utilized to prevent coal dust explosions in coal mines world-wide. The United States is one of the few countries that does not regulate or employ all four of these safety practices. Additionally, a review of past research into coal dust explosions …

Numerical Simulation Study Of Factors Affecting Production Well Gel Treatment Using Linear Models With Crossflow, Kewei Shi

Masters Theses

"Conformance control is an inevitable topic related to water-flooding. Polymer gel has been proved to enhance oil recovery by blocking the existing water-breakthrough channels. Water that is injected subsequently will be directed to the unswept portion of the reservoir, replacing part of the remaining oil and increasing the oil-recovery factor. Prior to pilot tests of polymer gel treatment, laboratory experiments and numerical simulations are used to design the tests. Understanding physical meanings of key parameters that affect polymer gel treatment and relating the parameters from lab data and the simulator benefit field operation design.

This thesis study tries to evaluate …

Cellular Hitchhiking Via Injectable Microparticles, Daniel Smith

Masters Theses

"Tissue engineering is a process of developing new tissues in a host. Tissue engineering draws upon revitalizing damaged tissues that otherwise would not heal completely from the body's natural response. To augment the body's natural response to impairment, cells can be transplanted to the afflicted area to boost the healing response. Implementing these cells onto scaffolds and transplanting them into the body improves the healing response dramatically. Tissue regeneration improves when a biodegradable scaffold is used in conjunction with cells to augment the body's healing response. Microparticles provide a surface that can mimic the environment cells perceive in vivo, …

Proppant Transport With Varying Injection Points And Its Impact On Proppant Development Inside A Fracture, Shail Janakbhai Soni

Masters Theses

"This study presents experimental work which examines the effect of perforation placement and density on proppant placement within a hydraulic fracture. The study also investigates the effect of proppant angularity.

Experiments were conducted with ceramic proppant injected in a fracture slot model consisting of three injection points at the bottom, middle and top of the fracture slot, and two outlets, at the bottom and top of the fracture model. The effect of single point injection height was investigated by injecting solely at the bottom, middle or top of the apparatus, for both bottom and top outlet conditions. Multiple injection points …

The Role Of Flexural Slip In The Development Of Chevron Folds, Yuxing Wu

Masters Theses

"Chevron folds are characterized by straight limbs and narrow hinge zones. One of the conceptual models to initiate and develop chevron folds involves flexural slip during folding. While some kinematical models show the necessity for slip to initiate during chevron folding, recent numerical modeling studies of visco-elastic effective single layer buckle folding have shown that flexural slip does not result in chevron folds. In this study, several 2D finite element analysis models are run, distinguished by 1) geometry of the initial perturbation (sinusoidal and white noise), 2) varying thewavelength of the initial perturbation (10%, 50%, and 100% of the dominant …

Lyapunov Stability Analysis Of Switched Microgrid Systems, Bokang Zhou

Masters Theses

"In this thesis, a Lyapunov-based method for analyzing the stability of a switched microgrid system is proposed. First, a small second-order system is explored as example to demonstrate the effectiveness of switching patterns on the stability of a system switching among different respectively stable operating points. Lyapunov function is employed in order to determine the proper state-based switching conditions under which global stability is guaranteed, or under which the system is driven unstable. Then, a linearized statespace model of a looped seven-node microgrid is established. Solid-state transformers (SSTs), distributed energy storage devices and synchronous generators are introduced and modeled in …

Numerical Modeling Of Capillary-Driven Flow In Open Microchannels: An Implication Of Optimized Wicking Fabric Design, Mehrad Gholizadeh Ansari

Masters Theses

"The use of microfluidics to transfer fluids without applying any exterior energy source is a promising technology in different fields of science and engineering due to their compactness, simplicity and cost-effective design. In geotechnical engineering, to increase the soil's strength, hydrophilic wicking fibers as type of microfluidics have been employed to transport and drain water out of soil spontaneously by taking advantage of natural capillary force without using any pumps or other auxiliary devices. The objective of this study is to understand the scientific mechanisms of the capability for wicking fiber to drain both gravity and capillary water out of …

3d Seismic Imaging Of Submarine Stratovolcanic And Salt Structures Beneath The Taranaki Basin, New Zealand And The Gulf Of Mexico, Ersin Erdem Unkaracalar

Masters Theses

"The relationship of submarine stratovolcanic and salt structures with overlying sediments creates a significant role in the petroleum system due to the emplacement and burial of volcano and salt. This study characterizes the spatial and temporal distribution of structural and stratigraphic features associated with submarine stratovolcano and salt body to provide insights for elements and processes of petroleum geology related to regional tectonics.

The stratovolcanic and salt structures are clearly identified on seismic sections. However, distortion of ray paths passing through the salt and turning seismic waves prevents accurate identification of steep flanks of salt. The seismic response to a …

Grain Refinement Of High Alloy Stainless Steels In Sand And Directionally Solidified Castings, Dustin Alan Arvola

Masters Theses

"The goal of this research project is to develop an industrially viable melting process that will control the crystallization macrostructure of austenitic grades of cast steels. Titanium nitride (TiN) has proven to be an effective grain refiner of austenite. Theoretical simulation and experimental application has led to the development of a repeatable grain refining melt process for austenitic stainless steel alloys.

Grain refinement of the as-cast structure of Cr-Ni stainless steel alloys solidified with primary FCC, BCC and dual FCC/BCC phases was studied experimentally. Refinement was achieved in both cast ferritic and austenitic grades. Dual solidification of …

Reprocessing Of 3c-2d Seismic Reflection Data From The Spring Coulee Field, Alberta, Yasin Demir

Masters Theses

"The 3C-2D seismic datasets were acquired in 2008 in the Spring Coulee Field, Alberta, which is located in Township 4, Range 23, and west of the 4th Meridian in the Alberta Basin. Line 2008-SC-01 was reprocessed to obtain better image of the formation targeted at between 1300 ms and 1400 ms. The depositional settings of the Madison Formation consist of shallow and carbonate shelf deposits. The processing workflow was designed by testing several methods, algorithms, and parameters, and finding the optimal processing solution. The processing steps included elevation statics, noise suppression, deconvolution operator, and 2D Kirchhoff poststack time migration. In …

Evaluating Microgrid Effectiveness In Transitioning Energy Portfolios, Jacob Marshal Hale

Masters Theses

"Microgrid energy systems have emerged as a potential solution to rising greenhouse gas emissions from dependence on fossil fuels. This research provides a framework for evaluating the utility of microgrids. Three key findings are presented: use of a state-of-the-art matrix (SAM) analysis to identify gaps in key research areas that inhibit wide-spread microgrid adoption, development of a system dynamics (SD) model, and a cost benefit analysis case study to evaluate microgrid feasibility in partially meeting the energy demand of a building. Governments play a central role in developing clean energy strategies. A SAM was developed to determine if key microgrid …

A Hybrid Cavity And Parallel-Plate Peec Method For Analysis Of Complex Power Net Area Fills, And A Tool Development For Peak Distortion Analysis, Chenxi Huang

Masters Theses

"Modern ASICs and FPGAs are becoming more and more dense, which is causing an increasing demand of the current draw from the power distribution network (PDN). And one of the main design objectives of a power distribution network is to reduce the voltage noise ripple below a specified allowable limit. Although the target impedance is a commonly used criterion in most PDN designs, it may not be efficient because it's usually rather pessimistic. Herein a time domain voltage ripple decomposition approach is proposed to avoid overdesign as well as provide design guidance to PI engineers. Based on a physics-based circuit …

The Importance Of Chemical Grouting Materials For Optimum Mechanical Performance With Different Soil Conditions, Yusuf Alper Cinar

Masters Theses

"Grouting is a frequently used technique for controlling the water inflow and reinforcement of soil and rock. Even though cement-based grouting materials have been well characterized, ongoing improvements of chemical grouting materials create a need to better understand the characteristics of these materials in order to increase the efficiency of grouting applications. The purpose of this study is to characterize three common chemical grouting materials by exploring their mechanical performance under varying initial soil conditions. Performance decision criteria consist of the Unconfined Compressive Strength (UCS) and slake durability test results, observation of penetration ability, and comparison of the findings. The …

Developing An Energy Efficient Real-Time System, Aamir Aarif Khan

Masters Theses

"Increasing number of battery operated devices creates a need for energy-efficient real-time operating system for such devices. Designing a truly energy-efficient system is a multi-staged effort; this thesis consists of three main tasks that address different aspects of energy efficiency of a real-time system (RTS).

The first chapter introduces an energy-efficient algorithm that alternates processor frequency using DVFS to schedule tasks on cores. Speed profiles is calculated for every task that gives information about how long a task would run for and at what processor speed. We pair tasks with similar speed profiles to give us a resultant merged speed …

Computational Investigation Of Polymer Electrolyte Membrane Fuel Cell With Nature-Inspired Fibonacci Spiral Flow Field, Suleyman Kose

Masters Theses

"Polymer electrolyte membrane fuel cells (PEMFC) are promising clean energy devices. The flow field design has crucial role in PEMFC performance for effective distribution of reactants and removal of products. Several nature-inspired flow field designs have recently been proposed in the literature. Common characteristics of these designs were sudden changes in the flow direction through sharp bends and flow field geometries restrained to areas having corners. In this thesis, Fibonacci spiral configuration, which is found in the nature from hurricanes to seashells, was considered for flow field pattern of a PEMFC. Contrary to the bio-inspired designs proposed in previous studies, …

Effects Of Terrain-Based Altimetry On Navigation Performance, Kenneth Michael Kratzer

Masters Theses

"Navigation filters used during an entry, descent, and landing scenario often receive measurements related to the terrain over which the vehicle is traversing. Models of the terrain can be presented in varying degrees of fidelity, providing increasingly realistic and accurate models of the surface. While it is ideal to provide the filter with the most realistic model possible, the performance is limited by the strict nature of the real time scenario. Therefore, it is of interest to determine what level of fidelity is necessary to achieve an accurate filtering solution. Determining how best to incorporate terrain-related data into navigation solutions …

Analyzing Sensor Based Human Activity Data Using Time Series Segmentation To Determine Sleep Duration, Yogesh Deepak Lad

Masters Theses

"Sleep is the most important thing to rest our brain and body. A lack of sleep has adverse effects on overall personal health and may lead to a variety of health disorders. According to Data from the Center for disease control and prevention in the United States of America, there is a formidable increase in the number of people suffering from sleep disorders like insomnia, sleep apnea, hypersomnia and many more. Sleep disorders can be avoided by assessing an individual's activity over a period of time to determine the sleep pattern and duration. The sleep pattern and duration can be …

Designed Extrudate For Ceramic Additive Manufacturing, Devin Mcmillen

Masters Theses

"The objective of this thesis work was to design ceramic paste systems that assist in achieving a high theoretical density ( > 95%) after deposition by a novel additive manufacturing process, i.e. Ceramic On-Demand Extrusion (CODE). The work is encompassed in five main sections: Sections 1 and 2 provide an introduction and literature review of relevant topics for the following sections of experimentation. Section 3 provides an analysis of a reaction chemistry to identify three discrete materials that could be combined via CODE and result in zirconium diboride (ZrB₂) post-sintering. Section 4 describes the development of a high solids …

Quantifying On-Orbit Performance Of Cubesat Micropropulsion Systems By Observing Orbital Element Variations, Bradyn William Morton

Masters Theses

"The Advanced Propulsion Experiment mission in development by the Missouri University of Science and Technology's satellite research team (M-SAT) is a technology demonstration mission of a multi-mode propulsion system. The true test of any satellite propulsion system is the on-orbit performance. The purpose of this research is to develop methods for quantifying the on-orbit performance of the multi-mode propulsion system. This performance can be determined by observing the small variations in the orbital element parameters and using a differential corrector with the Gauss Variation of Parameter equations. Furthermore, this research could be used to determine and quantify a propulsion system's …

Research And Development Of Optically Transparent Join With Low Processing Temperatures, Eric Kevin Muskovin

Masters Theses

The purpose of this study was to investigate durable solar cell cover glass joins produced by diffusion bonding with deep eutectic solvents (DES) and to develop a novel process of joining optically transparent materials at low temperatures. A joined PV cell-glass specimen was characterized using Raman, μ-FTIR, SEM-EDS, and thin-film XRD. DESs were created with malonic acid (MAL) and choline chloride (ChCl) of varying composition factors (CF; CF=MAL/ChCl). Joining borosilicate glass coupons was attempted using DESs with CF = 0.65 and 1 at temperatures between 100-150 °C for 20 hours. Joining the glass coupons failed at all temperatures and oxygen …

Modeling And Control Of Three-Phase Grid-Connected Pv Inverters In The Presence Of Grid Faults, Paresh Vinubhai Patel

Masters Theses

"A two-stage photovoltaic grid-connected microgrid modeling approach is presented in this work. The purpose of the modeling is the behavior study of the microgrid during the low-voltage event on the grid. A complete mathematical model is discussed for each component of the system. The MPPT of the photovoltaic system is integrated with the boost controller to inject the constant current in the DC-link. The boost converter and the inverter control is implemented using the cascaded PI control. A dual second-order generalized integrator (DSOGI) method is implemented for the sequence extraction. The inverter controller is designed to meet the grid-code requirement …

Precise Energy Efficient Scheduling Of Mixed-Criticality Tasks & Sustainable Mixed-Criticality Scheduling, Sai Sruti

Masters Theses

"In this thesis, the imprecise mixed-criticality model (IMC) is extended to precise scheduling of tasks, and integrated with the dynamic voltage and frequency scaling (DVFS) technique to enable energy minimization. The challenge in precise scheduling of MC systems is to simultaneously guarantee the timing correctness for all tasks, hi and lo, under both pessimistic and optimistic (less pessimistic) assumptions. To the best of knowledge this is the first work to address the integration of DVFS energy conserving techniques with precise scheduling of lo-tasks of the MC model.

In this thesis, the utilization based schedulability tests and sufficient conditions for such …

The Effects Of Privacy Violation Abstractness On Privacy Attitudes And Behaviors, Delicia Anceisao Vaz

Masters Theses

"This research investigates new methods to present privacy policy information to consumers. It makes the argument that current privacy policies do not present consumers with information in a manner that helps align their privacy attitudes with their privacy behaviors. With the introduction of smart appliances to the market, it is critical that appropriate privacy policies are created to equip consumers with information that is easy to understand. Neutral Examples and Risk Examples were created along with the Traditional Content of a privacy policy. These three components were used in different combinations to provide privacy information about smart appliances. Additionally, it …

Effect Of Microstructural Features On Steel Machinability, Mark C. Emmendorfer

Masters Theses

Non-metallic inclusions can have a tremendous impact on the machinability of steel. Some oxide inclusions such as alumina, spinel, and other refractory abrasive oxide inclusions can have a detrimental effect on machinability. Modification of oxide inclusions by calcium treatment can promote the formation of low melting point oxides such as anorthite and gehlenite inclusions that can assist in chip formation and form a lubricating layer on the rake surface of the machine tool. MnS is known to be beneficial to improving the machinability of steel. They assist in chip formation by being heavily deformed in the primary shear zone. Sulfide …