Digital Commons Network^™

A Contingency Base Camp Framework Using Model Based Systems Engineering And Adaptive Agents, Dustin Scott Nottage

Doctoral Dissertations

"This research investigates the use of adaptive agents and hybridization of those agents to improve resource allocation in dynamic systems and environments. These agents are applied to contingency bases in an object oriented approach utilizing Model-based Systems Engineering (MBSE) processes and tools to accomplish these goals. Contingency bases provide the tools and resources for the military to perform missions effectively. There has been increasing interest in improving the sustainability and resilience of the camps, as inefficiencies in resource usage increases. The increase in resource usage leads to additional operational costs and added danger to military personnel guarding supply caravans.

The …

Optimization In Microgrid Design And Energy Management, Tu Anh Nguyen

Doctoral Dissertations

"The dissertation is composed of three papers, which cover microgrid systems performance characterization, optimal sizing for energy storage system and stochastic optimization of microgrid operation. In the first paper, a complete Photovoltaic-Vanadium Redox Battery (VRB) microgrid is characterized holistically. The analysis is based on a prototype system installation deployed at Fort Leonard Wood, Missouri, USA. In the second paper, the optimal sizing of power and energy ratings for a VRB system in isolated and grid-connected microgrids is proposed. An analytical method is developed to solve the problem based on a per-day cost model in which the operating cost is obtained …

Energy Deposition Into Heavy Gas Plasma Via Pulsed Inductive Theta-Pinch, Ryan Alan Pahl

Doctoral Dissertations

"The objective of this research is to study the formation processes of a pulsed inductive plasma using heavy gases, specifically the coupling of stored capacitive energy into plasma via formation in a theta pinch coil. To aid in this research, the Missouri Plasmoid Experiment Mk. I (and later Mk. II) was created.

In the first paper, the construction of differential magnetic field probes are discussed. The effects of calibration setup on B-dot probes is studied using a Helmholtz coil driven by a vector network analyzer and a pulsed-power system. Calibration in a pulsed-power environment yielded calibration factors at least 9.7% …

Modeling And Optimization Of Energy Storage System For Microgrid, Xin Qiu

Doctoral Dissertations

"The vanadium redox flow battery (VRB) is well suited for the applications of microgrid and renewable energy. This thesis will have a practical analysis of the battery itself and its application in microgrid systems. The first paper analyzes the VRB use in a microgrid system.

The first part of the paper develops a reduced order circuit model of the VRB and analyzes its experimental performance efficiency during deployment. The statistical methods and neural network approximation are used to estimate the system parameters. The second part of the paper addresses the implementation issues of the VRB application in a photovoltaic-based microgrid …

Energy Aware And Privacy Preserving Protocols For Ad Hoc Networks With Applications To Disaster Management, Mayank Raj

Doctoral Dissertations

"Disasters can have a serious impact on the functioning of communities and societies. Disaster management aims at providing efficient utilization of resources during pre-disaster (e.g. preparedness and prevention) and post-disaster (e.g. recovery and relief) scenarios to reduce the impact of disasters. Wireless sensors have been extensively used for early detection and prevention of disasters. However, the sensor's operating environment may not always be congenial to these applications. Attackers can observe the traffic flow in the network to determine the location of the sensors and exploit it. For example, in intrusion detection systems, the information can be used to identify coverage …

Crustal Thickness And Vp/Vs Beneath The Western United States: Constraints From Stacking Of Receiver Functions, Uranbaigal Purevsuren

Doctoral Dissertations

"This study investigates crustal characteristics beneath the western United States. Crustal parameters, including crustal thickness (H), mean Vp/Vs, and the sharpness of the Moho as quantified by the amplitude of the P-to-S converted phases from the Moho, are measured at a total of 1000 permanent and portable broadband seismic stations using over 150,000 receiver functions recorded between 1988 and 2012. The study area is composed of a diverse set of tectonic provinces formed by a series of tectonic events, and is thus ideal for investigating crustal formation and modification by different tectonic processes. The resulting crustal thickness varies from …

Investigation Of Projectile Coherence Effects In Fully Differential Studies Of 75 Kev Proton - H₂ Collisions, Sachin Sharma

Doctoral Dissertations

"Fully differential cross sections (FDCS) have been measured for single ionization of H₂ by 75 keV proton impact with varying transverse coherence length of the projectiles. As reported in recent years, the scattering angle dependence of the doubly differential cross sections (DDCS) are significantly affected by the projectile coherence properties. The interference structures were observed for the coherent beam, however were absent for an incoherent beam. Interestingly, the FDCS measurements for fixed momentum transfer do not suggest significant differences between the coherent and incoherent cross sections. However, for the FDCS with fixed recoil-ion momentum, clear differences between the two …

Thermal-Fluid Modeling Of The Missouri S&T Reactor, Susan Maria Sipaun

Doctoral Dissertations

"Thermal-fluid modeling of the Missouri University of Science and Technology Reactor (MSTR) was carried out using a computational fluid dynamics code (CFD), STAR-CCM+. First, a three-dimensional parallel-plate model was developed, and the cosine-shaped heat flux was applied to the MSTR core. Simulation results for fluid flow under natural convection condition show coolant temperature and velocity as a function of core power. A characteristic equation for the parallel-plate model was obtained based on Forchheimer's flow equation. The inertial resistance tensor and viscous resistance tensor were found to be 281005 kg/m^4 and 7121.6 kg/m^3 respectively. The MSTR core was then defined as …

Carbon Dioxide - Heavy Oil Systems: Thermodynamics, Transport And Interfacial Stability, Truynh Quoc My Duy Tran

Doctoral Dissertations

"Conventional oil recovery leaves behind around 67% of original oil in place for light oils and all of it for heavy oils. The carbon dioxide flooding process is the cheapest among the recovery methods for the next stage. The interest here lies in recovering heavy oil. When CO₂ dissolves in oil, it increases the volume of oil, squeezes it out of narrow capillaries and the viscosity of oil drops by up to an order of magnitude. Starting with the available data with and without CO₂ in heavy oil, the free volume theory is used to predict these physical …

Impact Of Slickwater Fracturing Fluid Compositions On The Petrophysical Properties Of Shale And Tightsand, Yongpeng Sun

Doctoral Dissertations

"A tight reservoir always requires hydraulic fracturing before production to increase production rate. The additives in hydraulic fluids are highly considerable for a successful stimulation. A friction reducer is often used to reduce the flowing friction in the wellbore during hydraulic fracturing. Extensive researches have been conducted to examine the extent it can reduce the fluid friction in tubings; however, no research has been reported on its behavior in a reservoir, which is related to the fracture extension. A breaker is also pumped into the formation to degrade the friction reducer. However, it is not clear that what is the …

Semiconductor Nanocrystals For Novel Optical Applications, Jong-Sik Moon

Doctoral Dissertations

“Inspired by the promise of enhanced spectral response, photorefractive polymeric composites photosensitized with semiconductor nanocrystals have emerged as an important class of materials. Here, we report on the photosensitization of photorefractive polymeric composites at visible wavelengths through the inclusion of narrow band-gap semiconductor nanocrystals composed of PbS. Through this approach, internal diffraction efficiencies in excess of 82%, two-beam-coupling gain coefficients in excess of 211 cm^-1, and response times 34 ms have been observed, representing some of the best figures-of-merit reported on this class of materials. In addition to providing efficient photosensitization, however, extensive studies of these hybrid composites …

Advanced Active Rectifiers For Electric Vehicle Battery Charging, Darren Lee Paschedag

Doctoral Dissertations

"In a big picture sense, the work presented in this dissertation is in the area of fully electric or plug-in hybrid electric vehicles. Both of these vehicle types require an external power source to fully charge their large amount of energy storage. For most consumers this means plugging their vehicle into the utility which necessitates battery charging circuitry. More specifically, this dissertation focuses on the power factor correction (PFC) circuit which makes up one part of a typical battery charging system. The circuits presented here are not dependent on battery chemistry, so they can be utilized with all popular chemistries …

Proactive Search: Using Outcome-Based Dynamic Nearest-Neighbor Recommendation Algorithms To Improve Search Engine Efficacy, Christopher Shaun Wagner

Doctoral Dissertations

"The explosion of readily available electronic information has changed the focus of data processing from data generation to data discovery. The prevalent use of search engines has generated extensive research into improving the speed and accuracy of searches. The goal of this research is to accurately predict user behavior as a means to proactively improve speed, accuracy, and predictability of search engines. The proactive approach eliminates query entry time and hence reduces the overall processing time, improving speed. Assuming success, the user locates an electronic resource of interest, improving accuracy.

Algorithms that have been shown to predict many vastly different …

Longitudinal Analysis Of Crash Frequency Data, Mojtaba Ale Mohammadi

Doctoral Dissertations

"This study comprises mainly of three papers. First, a systematic evaluation of the effects of Missouri's Strategic Highway Safety Plan between 2004 and 2007 is presented. Negative binomial regression models were developed for the before-through-change conditions for the various collision types and crash severities. The models were used to predict the expected number of crashes assuming with and without the implementation of MSHSP. This procedure estimated significant reductions of 10% in crashes frequency and a 30% reduction for fatal crashes. Reductions in the number of different collision types were estimated to be 18-37%. The results suggest that the MSHSP was …

Modeling And Simulation Of Continuous Fiber-Reinforced Ceramic Composites, Venkata Bheemreddy

Doctoral Dissertations

"Finite element modeling framework based on cohesive damage modeling, constitutive material behavior using user-material subroutines, and extended finite element method (XFEM), are developed for studying the failure behavior of continuous fiber-reinforced ceramic matrix composites (CFCCs) by the example of a silicon carbide matrix reinforced with silicon carbide fiber (SiC/SiCf) composite. This work deals with developing comprehensive numerical models for three problems: (1) fiber/matrix interface debonding and fiber pull-out, (2) mechanical behavior of a CFCC using a representative volume element (RVE) approach, and (3) microstructure image-based modeling of a CFCC using object oriented finite element analysis (OOF). Load versus displacement behavior …

Performance Evaluation Of Polyurethane Composites Using Vacuum Infusion Process, Mohaned M. Mohamed

Doctoral Dissertations

"Glass fiber-reinforced polymer composites have promising applications in infrastructures due to their low cost, high specific stiffness/strength, and corrosion resistance. The pultrusion process is often used to manufacture glass fiber-reinforced polyurethane (PU) composite. The objective of this study is to use thermoset PU resin to manufacture high quality composites for infrastructure applications using vacuum assisted resin transfer molding (VARTM) process. Using VARTM to fabricate PU resins presents unique challenges. Several modifications however have helped with overcoming these problems. In part I of the research, the mechanical performance of two different PU resin not only evaluated but also compared to one …

Modeling And Simulation Of Hydrokinetic Composite Turbine System, Haifeng Li

Doctoral Dissertations

"The utilization of kinetic energy from the river is promising as an attractive alternative to other available renewable energy resources. Hydrokinetic turbine systems are advantageous over traditional dam based hydropower systems due to "zero-head" and mobility. The objective of this study is to design and analyze hydrokinetic composite turbine system in operation. Fatigue study and structural optimization of composite turbine blades were conducted. System level performance of the composite hydrokinetic turbine was evaluated. A fully-coupled blade element momentum-finite element method algorithm has been developed to compute the stress response of the turbine blade subjected to hydrodynamic and buoyancy loadings during …

Development Of A Nitrogen Incorporated Ultrananocrystalline Diamond Film Based Field Emitter Array For A Flat Panel X-Ray Source, Chrystian Mauricio Posada

Doctoral Dissertations

"As an alternative to conventional X-ray sources, a flat panel transmission X-ray source is being developed. A field emitter array (FEA) prototype to be incorporated as cold cathode in this flat panel X-ray source was fabricated for this work. Using the Particle-in-Cell code OOPIC Pro, an initial FEA was designed through simulations. Based on the simulation results, a FEA prototype was fabricated using conventional microfabrication techniques. Planar nitrogen-incorporated ultrananocrystalline diamond (N-UNCD) films were used as field emitters. This N-UNCD based FEA prototype was composed of 9 pixels distributed in a 3x3 array, with a pixel size of 225x225 µm, and …

Bioactive Glass/Polymer Composites For Bone And Nerve Repair And Regeneration, Ali Mohammadkhah

Doctoral Dissertations

"Bioactive glasses have several attractive properties in hard and soft tissue repair but their brittleness limited their use, as scaffolding materials, for applications in load- bearing hard tissue repair. At the same time, because of their bioactive properties, they are being studied more often for soft tissue repair. In the present work, a new glass/polymer composite scaffold was developed for the repair of load-bearing bones with high flexural strength and without brittle behavior. The new composites have 2.5 times higher flexural strength and ~100 times higher work of fracture (without catastrophic failure) compared to a similar bare glass scaffold.

Also …

Electric-Drive Vehicle Emulation Using Advanced Test Bench, Poria Fajri

Doctoral Dissertations

"Vehicle electrification is considered to be the most promising approach toward addressing the concerns on climate change, sustainability, and rapid depletion of fossil fuel resources. As a result electric-drive vehicle (EDV) technology is becoming the subject of many research studies, from academia and research laboratories to automotive industries and their suppliers. However, a crucial step toward the success of EDV implementation is developing test platforms that closely emulate the behavior of these vehicles.

In this dissertation, a new approach for emulating an EDV system on a motor/dynamometer test bench is investigated. Two different methods of emulation are discussed which are …

Two New Families Of High-Gain Dc-Dc Power Electronic Converters For Dc-Microgrids, Venkata Anand Kishore Prabhala

Doctoral Dissertations

"Distributing the electric power in dc form is an appealing solution in many applications such as telecommunications, data centers, commercial buildings, and microgrids. A high gain dc-dc power electronic converter can be used to individually link low-voltage elements such as solar panels, fuel cells, and batteries to the dc voltage bus which is usually 400 volts. This way, it is not required to put such elements in a series string to build up their voltages. Consequently, each element can function at it optimal operating point regardless of the other elements in the system. In this dissertation, first a comparative study …

Development Of A Flat-Panel X-Ray Source, Edwin Joseph Grant

Doctoral Dissertations

"A novel flat-panel transmission type X-ray source was developed for both medical and industrial use. Depending on the geometry of the given situation, the flat-panel X-ray source could be used in tomography, radiography or tomosynthesis. Furthermore, the unit could be used as a portable X-ray scanner or an integral part of an existing detection system. The design incorporates a field emission cathode made of ultra-nanocrystalline diamonds (UNCD) doped with nitrogen. These field emitters show good electron output at low power and can be deposited over large areas as is the case with carbon nanotube "forest" (CNT) cathodes. This work presents …

Mechanistic Identification Of Specific Force Coefficients In Endmilling Inconel 718 Under Four Cooling Strategies, Mahmood Shaman Ameen

Masters Theses

“This thesis presents the results of experimental investigations of the mechanistic identification of specific force coefficients for uncoated bull-nose and uncoated wavy-edge/bull-nose helical endmilling of Inconel 718 under emulsion, minimum quantity lubrication (MQL), cryogenic (LN₂), and combined (MQL + LN₂) cooling. Several slot milling tests were conducted on Inconel 718 workpiece block with depth of cut 1.25 mm. The cutting parameters were varied as: spindle speed, n = 250 and 750 rev/min, feedrate, f = 25–75 mm/min by using uncoated carbide bull-nose helical endmill. Also 24 peripheral milling tests were conducted on Inconel 718 workpiece block …

Software-Based Instrumentation For Analysis Of Electrostatic Discharge Effects, Antonio James Sabatini

Masters Theses

”Failures caused by electrostatic discharge (ESD) compromise the reliability of embedded systems. Peripherals such as the universal serial bus (USB) are particularly vulnerable, as isolating them to avoid electromagnetic interference would defy their purpose - facilitating communication with and/or by the embedded system. Better understanding the propagation of failures that result from ESD can facilitate defensive development of hardware and software for embedded systems, but is hampered by the lack of non-invasive and lightweight instrumentation techniques.

The original contribution of this thesis is the design and development of software-based instrumentation for monitoring the reaction of the USB peripheral of an …

Evaluation Of Ceramic Coaxial Cable Sensors For Long-Term In-Situ Monitoring Of Geologic Co₂ Injection And Storage, Yurong Li

Masters Theses

"Monitoring is an essential component of CO₂ injection and storage projects in order to manage the injection process, identify leakage risks, provide early failure warnings, determine the movement of CO₂ plume and provide input into reservoir models. In-situ monitoring provides critical and direct data points that can be used to fulfill the above objectives. However, downhole sensors that can withstand the harsh conditions and run over decades of the project life cycle remain unavailable. A new idea of ceramic coaxial cable temperature, pressure and strain sensor has recently been put forward and the sensors are under development.

A high pressure …

Workplace Sleepiness: Causes, Consequences And Countermeasures, Neda Khalafi

Masters Theses

"Sleep deprivation is an epidemic problem in our society that adversely affects the quality and safety of our daily lives. At home and on the job, inadequate sleep is associated with considerable social, financial, and health-related costs, due to instability of waking functions. Research has shown that, sleep deprivation among workers, whether from sleep disorders, lifestyle or shift work, can hinder the proper performance, and in extreme cases may pose hazard to the workers themselves and their environment. Deficits in daytime performance can have profound effects in the processing industry where workers are often required to perform monotonous tasks that …

An Interactive Product Development Model In Remanufacturing Environment: A Chaos-Based Artificial Bee Colony Approach, Vishwa V. Kumar

Masters Theses

"This research presents an interactive product development model in re-manufacturing environment. The product development model defined a quantitative value model considering product design and development tasks and their value attributes responsible to describe functions of the product. At the last stage of the product development process, re-manufacturing feasibility of used components is incorporated. The consummate feature of this consideration lies in considering variability in cost, weight, and size of the constituted components depending on its types and physical states.

Further, this research focuses on reverse logistics paradigm to drive environmental management and economic concerns of the manufacturing industry after the …

Development Of Structural Basins And Domes On The Sinn El-Kaddab Plateau, Egypt: Insights From In Situ Data And Application Of Moderate Resolution Orbital Imagery Of The Seiyal Fault, Thomas J. Jerris

Masters Theses

"The Seiyal Fault, one of many east-west trending faults located in the Western Desert of Egypt, and associated structural basins and domes are investigated using remote sensing imagery and field studies. Analysis of Shuttle Reconnaissance Topography Mission data, multi-spectral data from the Landsat Thematic Mapper (LM), Landsat 7 Enhanced Thematic Mapper Plus (ETM+), the Advanced Spaceborne Thermal Emission and Reflectometer (ASTER) data, and imagery from Google Earth. Band combinations 3-2-1 and 7-4-2 in ETM+ and 3N-2-1 and 7-3-1 in ASTER, and Google Earth provided the most useful images for geologic mapping. The Seiyal Fault is best characterized as a zone …

Impact Of Fracture Spacing And Mechanical Parameter Anisotropy On Fracture Width In Horizontal Wells In Shales, Deepak Gokaraju

Masters Theses

"The success of economically viable production of oil and gas from ultra-low permeability shale reservoirs depends on the creation of an extensive fracture network through hydraulic fracture stimulation. Multiple hydraulic fractures are created simultaneously in each stage to increase the surface area of contact between the wellbore and reservoir. The spacing between fractures is an important component to consider when developing an optimum stimulation design. An important aspect of shale rock properties is that shales are inherently anisotropic with a horizontal plane of isotropy (transversely isotropic) due to their finely layered structure. This study aims to provide an insight into …

Bridge Deck Condition Assessment Using Destructive And Nondestructive Methods, Brandon Tyler Goodwin

Masters Theses

"This study investigates two bridge decks in the state of Missouri using both nondestructive and destructive testing methods. The Missouri Department of Transportation (MoDOT) is responsible for the monitoring and maintenance of over 10,000 bridges. Currently monitoring of these bridges includes a comprehensive visual inspection. In this study, ground-coupled ground penetrating radar (GPR) is used to estimate deterioration, along with other traditional methods, including visual inspection, and core evaluation. Extracted core samples were carefully examined, and the volume of permeable pore space was determined for each core. After the initial investigation, the two bridges underwent rehabilitation using hydrodemolition as a …