Digital Commons Network^™

The Dynamic Behavior Of A Solid State Transformer (Sst) During Recloser Operation In Distribution Systems, Fahd Amin Hariri

Masters Theses

"Electrical power systems are continuously facing increasing electrical power demand in the last years to meet the requirements of modern life style. In order to satisfy such needs electricity authorities are taking appropriate measures to enhance the performance of power networks. One of the solutions to meet the customer's demands for energy was the trend to use the renewable energy. The increasing use of renewable energy and other distributed generation sources made the electrical grid more complex. Many researches have been carried out to find out solutions to overcome this complexity. One of these researches -- which was on a …

Day Of The Week Effect In Returns And Volatility Of The S&P 500 Sector Indices, Juan Liu

Masters Theses

"Previous studies have shown that returns associated with the stock market or foreign exchange's futures show variations across the day of the week. On such study, that employs a modified GARCH model for estimation, shows that returns associated with the S&P 500 stock index is highest on Wednesday and lowest returns on Monday. The same study shows that volatility is highest on Fridays and lowest on Wednesdays. In this study we investigate if this day-of-the-week effect on returns and volatility is present in the different sectors that constitute the S&P 500 index. The data set used provides daily returns from …

The Development Of Near Field Probing Systems For Emc Near Field Visualization And Emi Source Localization, Hui He

Masters Theses

"The objectives of this research are to visualize the frequency dependent electromagnetic field distribution for electromagnetic compatibility (EMC) applications and the radiating source reconstruction on complex shaped electronic systems. This is achieved by combining near field probing with a system for automatically recording the probe position and orientation. Due to the complexity of the shape of the electronic systems of interest, and for utilizing the expertise of the user, the probe will be moved manually not robotically. Concurrently, the local near field will be recorded, associated with the location and displayed at near real time on the captured 3D geometry …

Optimum Acquisition And Processing Parameters For Multichannel Analysis Of Surface Waves Using 3d Electrical Resistivity Tomography As Control, Uchenna Chibuzo Nwafor

Masters Theses

"Multichannel Analysis of Surface Waves (MASW) and Electrical Resistivity Tomography (ERT) data were acquired in the Newburg, Missouri with the goal of determining optimum MASW acquisition parameters. Users of the MASW tool generally state that greater geophone intervals and greater shot-to-receiver offsets provide for more accurate results. The objective was to determine if this "rule of thumb" applies in karst terrain.

ERT data were acquired along four traverses with eighty-four (84) electrodes at five feet spacing with SuperSting R8 Resistivity System using dipole- dipole array. The data were processed using Earth Imager to generate 2-D resistivity inversion and thereafter, Voxler …

Comparative Study Of Three Types Of Inverters Based On The Output Total Harmonic Distortion, Paterrson Thomas

Masters Theses

"In this thesis, three cases of power electronic inverters are taken into consideration to analyze their performance in terms of total harmonic distortion in their output voltage and output current. Firstly, a single H-bridge inverter is simulated. Staircase switching technique is used to generate the gating pulses for the switches. Only one switch is made to toggle for every half cycle. The fundamental harmonic component of the desired output voltage is considered to be 120 V. Secondly, the same topology is used with a Bipolar PWM gating technique. The switching frequency of the carrier wave is 33*60 Hz. Thirdly, a …

Freeze-Form Extrusion Fabrication Of Boron Carbide, Aaron Scott Thornton

Masters Theses

"Boron carbide is a safe, alternative to beryllium as a material for aerospace structures since it is also light-weight and exhibits high strength. This paper discusses a study of the Freeze-form Extrusion Fabrication (FEF) process to fabricate parts from boron carbide. Process parameters and hardware were modified to fabricate boron carbide specimens free of printed defects. Four-point bending tests were performed to measure the flexural strength of fabricated specimens. Observations of the presence of voids caused by ice crystals in fabricated parts led to further development and characterization of the boron carbide paste used with the FEF process. Additives were …

Formation And Evolution Of Spinel In Aluminum Killed Calcium Treated Linepipe Steels, Obinna Adaba

Masters Theses

"Magnesium aluminate (Spinel) inclusions have been observed to cause hook crack in line pipe steels. These inclusions are typically formed during liquid steel processing at the ladle metallurgy furnace (LMF) and subsequently modified by calcium to form less harmful liquid inclusions. Unfortunately, spinel inclusions are still sometimes observed in samples taken from the tundish and coil after calcium treatment.

The formation and evolution of spinel inclusions during liquid steel processing at two industrial mini mills was investigated by analysis of lollipop samples taken at different stages of the steelmaking process. The effect of reoxidation on the formation of spinels after …

Dependability Analysis And Recovery Support For Smart Grids, Isam Abdulmunem Alobaidi

Masters Theses

"The increasing scale and complexity of power grids exacerbate concerns about failure propagation. A single contingency, such as outage of a transmission line due to overload or weather-related damage, can cause cascading failures that manifest as blackouts. One objective of smart grids is to reduce the likelihood of cascading failure through the use of power electronics devices that can prevent, isolate, and mitigate the effects of faults. Given that these devices are themselves prone to failure, we seek to quantify the effects of their use on dependability attributes of smart grid. This thesis articulates analytical methods for analyzing two dependability …

Fault Interpretation And Reservoir Characterization Of The Farewell Formation Within Kerry Field, Taranaki Basin, New Zealand, Waleed Deefallah M Alotaby

Masters Theses

"The Kerry Field, located in the southern offshore Taranaki Basin, is a large liquid-rich gas accumulation with a thin (20 m) oil rim. The field was discovered by the New Zealand Oil & Gas in 1986 (well Kupe South-1). The gas and oil are trapped within a 9.2 km² fault-dependent three-way dip closure in the Paleocene Farewell Formation reservoir. Pressure, volume, and temperature (PVT) data indicate that the gas and oil columns in the field are in equilibrium with one another and are saturated at current reservoir conditions.

The Farewell Formation is the uppermost formation of the Kapuni Group …

Detecting Diesel Particulate Matter Using Real Time Monitoring Under The Influence Of An Exhaust Fan System, Yasir Helal Alghamdi

Masters Theses

"Diesel Particulate Matter (DPM) is a complex mixture of diesel exhaust gas that consists of carbon, ash, metallic abrasion particles, sulfates and silicates. The diesel soot particle includes a solid core made of elemental carbon, and organic carbon compound attached to the surface of the soot particle. The main source of DPM is diesel exhaust gas. The National Institute for Occupational Safety and Health (NIOSH) and the Environmental Protection Agency (EPA) have determined that DPM is the source of most of the emissions of carbon monoxide, carbon dioxide, oxide of nitrogen, and hydrocarbons in underground coal, metal and non metal …

Seismic Structural Investigation And Reservoir Characterization Of The Moki Formation In Maar Field, Taranaki Basin, New Zealand, Mohammed Dhaifallah M Alotaibi

Masters Theses

"The Maari Field is a large oil field located in the southern part of the Taranaki Basin, New Zealand. The field is bounded by two major structures, the Eastern Mobile Belt and Western Stable Platform. The Maari Field produces 40,000 BOPD (Barrels of Oil per Day) from five wells from reservoirs in the Moki Formation. The Miocene Moki Formation was deposited as part of the Wai-iti Group and consists of sandstone interbedded with siltstone and claystone. The sandstone of the Moki Formation is characterized by a submarine fan. It is distributed along the southern and central Taranaki shelf. Three-dimensional seismic …

An Improved Planar Cavity Model For Dielectric Characterization, Benjamin Jay Conley

Masters Theses

"Accurate characterization of the dielectric properties of the laminate materials used in printed circuit board fabrication is critical for maximizing the performance of modern high speed circuitry. While many techniques exist for characterizing dielectric materials, most existing techniques are either limited in accuracy or highly impractical for use with planar, copper-clad laminate sheets. A common method involves forming a cavity from the printed circuit board material and calculating the permittivity and dissipation factor from the measured resonant frequencies and quality factor of the cavity. This resonance technique makes the assumption of an ideal cavity, which leads to errors in both …

An Investigation Of Shear-Friction Of Lightweight Aggregate Concretes, Kristian Krc

Masters Theses

"This thesis reports the results of research initiated to evaluate the influence of lightweight aggregate type and casting procedure on shear transfer across an interface of concretes cast at different times. The topic of shear transfer has been evaluated and revisited in recent PCI Design Handbooks. In this test program, a series of cold joint as well as monolithic specimens are evaluated. The peak shear strength and post peak behavior are examined. The experimental matrix included 28 push-off specimens that were either cast monolithically or cast at different times creating the condition referred to as a cold joint. The variables …

Investigation Of Decoupling Capacitor Connection Methods Using Peec And Study Of Alien Crosstalk From A Broadr-Reach® Protocol Based System, Tamar Makharashvili

Masters Theses

"Power Distribution Network (PDN) for Printed Circuit Board (PCB) design requires proper power integrity analysis. In order to deliver a low-ripple DC voltage from a Voltage Regulator Module (VRM) to an Integrated Circuit (IC), a certain target input impedance should be achieved. Developing simple physics-based equivalent circuit models are essential for understanding how a system works and making crucial design decisions. In this work, the input impedance of a decoupling capacitor due to traces, pads and via discontinuities are investigated using the Physics-based Model Size Reduction (PMSR) method. Various decoupling capacitor connection methods are compared and design guidelines are provided …

Hyper-Heuristics For The Automated Design Of Black-Box Search Algorithms, Matthew Allen Martin

Masters Theses

"Within the field of Black-Box Search Algorithms (BBSAs), there is a focus on improving algorithm performance over increasingly diversified problem classes. However, these general purpose problem solvers have no guarantee to perform well on an arbitrary problem class that a practitioner needs to solve. The problem classes that the research in this thesis most applies to are difficult problems that are going to be solved multiple times. BBSAs tailored to one of these problem class can be expected to significantly outperform the more general purpose problem solvers, including canonical Evolutionary Algorithms (EAs). The first paper in this thesis explores a …

Cyber Security Research Frameworks For Coevolutionary Network Defense, George Daniel Rush

Masters Theses

"Cyber security is increasingly a challenge for organizations everywhere. Defense systems that require less expert knowledge and can adapt quickly to threats are strongly needed to combat the rise of cyber attacks. Computational intelligence techniques can be used to rapidly explore potential solutions while searching in a way that is unaffected by human bias.

Several architectures have been created for developing and testing systems used in network security, but most are meant to provide a platform for running cyber security experiments as opposed to automating experiment processes. In the first paper, we propose a framework termed Distributed Cyber Security Automation …

Detection And Cancellation Of Sinusoidal Fading Power Variation In Wireless Communication Systems, Sushruth Sastry

Masters Theses

"Fading channel estimation in wireless communication systems depends on an expected model for fading and any assumptions made about the channel itself. The bit error rate (BER) performance of the communication system is affected by how closely these assumptions made in designing the estimation technique match the deployment environment. Any unforeseen disturbances or hindrances in the environment deteriorate the BER performance of the system when the estimation system is not designed to combat such disturbances. To deal with such unforeseen obstacles, additional mathematical models can be proposed to model such disturbances and then the estimation techniques can either be reinforced …

Freeform Extrusion Fabrication Of Titanium Fiber Reinforced 13-93 Bioactive Glass Scaffolds, Albin Thomas

Masters Theses

"Although implants made with bioactive glass have shown promising results for bone repair, their application in repairing load-bearing long bones is limited due to their poor mechanical properties as compared to human bones. This thesis study is on freeform extrusion fabrication of silicate based 13-93 bioactive glass scaffolds reinforced with titanium fibers. A composite paste was prepared with 13-93 bioactive glass filled with titanium fibers (~16 µm in diameter and aspect ratio of ~250) having 0.1 to 0.4 vol. % of the bioactive glass scaffold. This paste was then filled into a syringe manually, and then extruded through a nozzle …

A Geochemical Investigation Of Co₂ Sequestration And Site Characterization At Two Missouri Locations, Robert Allen Swain

Masters Theses

"The feasibility of sequestering CO₂ in saline aquifers of Lamotte Formation sandstone was investigated at wells located near Thomas Hill power plant, Moberly, MO and Sioux City Power Plant in Florissant, MO. Governing factors of using aquifers for CO₂ disposal include water salinity, potential for carbonic acid buffering, rate of precipitation of carbonate minerals following CO₂ introduction into the host aquifer, and the integrity of the Davis and Derby-DoeRun shale as a trap rock to prevent migration of the CO₂ phase and carbonic acid into the overlying potable Ozark Aquifer.

Both in situ and laboratory methods …

Uncertainty Quantification Of Turbulence Model Closure Coefficients For Transonic Wall-Bounded Flows, John Anthony Schaefer

Masters Theses

"The goal of this work was to quantify the uncertainty and sensitivity of commonly used turbulence models in Reynolds-Averaged Navier-Stokes codes due to uncertainty in the values of closure coefficients for transonic, wall-bounded flows and to rank the contribution of each coefficient to uncertainty in various output flow quantities of interest. Specifically, uncertainty quantification of turbulence model closure coefficients was performed for transonic flow over an axisymmetric bump at zero degrees angle of attack and the RAE 2822 transonic airfoil at a lift coefficient of 0.744. Three turbulence models were considered: the Spalart-Allmaras Model, Wilcox (2006) k-ω Model, and the …

The Impact Of A Strong Local Supply Chain On Regional Economic Impacts Of Mining, Meiyu Xing

Masters Theses

"With growing social conflicts due to social and environmental concerns mines need to be able to create shared value for all stakeholder in their quest to promote sustainable development. Given the sensitivity of a mine's regional economy contribution to its supply chains, any improvement in supply chains strategy will be beneficial for mines and their stakeholders. The objectives of this work were to: (i) test the hypothesis that supply chain management strategy, by mines in a region, significantly affects regional economy; and (ii) develop a methodology to identify the critical backward commodities of a regional mining sector.

Valid methods have …

Shear-Friction Of Sand-Lightweight Clay And Slate Aggregate Concretes With Varied Reinforcement Ratios, Samantha Lynn Wermager

Masters Theses

"This thesis focuses on the structural properties of sand-lightweight aggregate concrete in terms of shear transfer strength at cold-joint interfaces. This type of interface is common for precast concrete connections which are typically designed using the shear-friction concept. This testing program was meant to expand the shear-friction database and evaluate the appropriateness of current shear-friction design provisions with respect to sand-lightweight concrete. This study builds on the work done by Shaw (2013) who studied lightweight expanded shale aggregate concrete. The current study included thirty-two push-off specimens constructed from sand-lightweight concrete with a target compressive strength of 5,000 psi. Either expanded …

Steam Flooding Screening And Eor Prediction By Using Clustering Algorithm And Data Visualization, Na Zhang

Masters Theses

"Enhanced Oil Recovery (EOR) techniques are vitally important in the oil industry because these techniques could not only extend the life of wells, but also produce 10% to 30% additional oil from the reservoir. However, selecting the most suitable EOR techniques for unknown reservoirs is not easy for decision making. Based on literature, EOR screening criteria could help to find the best candidates for unknown projects, which is classified into two categories: conventional EOR screening and advanced EOR screening. In this research, an artificial intelligent (AI) method, hierarchical clustering algorithm, is adapted to analyze both steam flooding projects and worldwide …

Paleogeographic And Paleoenvironmental Evolution Of Lacustrine And Fluvial Upper Triassic Zhangjiatan Shale Sequence, Ordos Basin, China, Qiuwan Yu

Masters Theses

"Detailed sequence stratigraphic and depositional systems analyses can effectively delineate factors and processes controlling deposition of fine-grained lacustrine sediments. Upper Triassic Zhangjiatan (ZJT) Shale Bed and adjacent strata in Ordos foreland basin was used as an example. A new depositional sequence model shows that the maximum regressive shoreline was more landward than that at the lowest lake-level. The study area is on the ramp margin, covering 100x90 km². Thin sections, cores and well-logs of 80 wells are used to calibrate log signatures, document lithofacies, and interpret depositional facies in a sequence stratigraphic context. The entire sequence thickens from …

Methods For Checking And Enforcing Physical Quality Of Linear Electrical Network Models, Mikhail Zvonkin

Masters Theses

"Most CAD tools allow system-level simulation for signal integrity by computing and connecting models together for the various sub-parts. The success of this model derivation depends on the quality of the network parameters. Different errors may seriously affect the quality of the frequency characterization: frequency-dependent measurement errors, errors due to the numerical simulation and/or discretization, etc. When these errors are large, model assembly and simulation becomes difficult and may even fail. This thesis gives an overview of the most significant properties of physically valid network parameters, describes existing methods for checking and enforcing these properties, and presents several new methodologies …

Mr4rf: Mem-Device With Impedance And Their Usage With Impedance Matching Networks For Passive Rfid Tags In The Uhf, George H. Harris

Masters Theses

"The passive RFID tag in the UHF has been employed in several different applications including, tracking, logistics, and as a sensing platform for the Internet of things (IoT). The tag is ideal for this industry due to its unique design. It harvests all of its energy from the environment, and is small, cheap, and requires little to no maintenance. However, there are two major issues limiting the potential of the passive RFID systems: the limited power harvested by the tag, and the high susceptibility to interference and coupling. In particular, dynamic environments render the traditionally fixed, RF impedance matching network …

Discrete-Time Neural Network Based State Observer With Neural Network Based Control Formulation For A Class Of Systems With Unmatched Uncertainties, Jason Michael Stumfoll

Masters Theses

"An observer is a dynamic system that estimates the state variables of another system using noisy measurements, either to estimate unmeasurable states, or to improve the accuracy of the state measurements. The Modified State Observer (MSO) is a technique that uses a standard observer structure modified to include a neural network to estimate system states as well as system uncertainty. It has been used in orbit uncertainty estimation and atmospheric reentry uncertainty estimation problems to correctly estimate unmodeled system dynamics. A form of the MSO has been used to control a nonlinear electrohydraulic system with parameter uncertainty using a simplified …

Analysis And Comparison Of Two High-Gain Interleaved Coupled-Inductor Boost Converters, Venkat Sai Prasad Gouribhatla

Masters Theses

"The main objective of this thesis is to compare and analyze two different high-gain dc-dc power electronic converters based on coupled inductors and capacitor-diode multiplier cells. The idea of these converters is to integrate the solar energy with a 400V DC microgrid. DC microgrids are more efficient, less expensive, and more reliable compared to AC microgrids. They also favor the integration of renewable energy sources. With the growing need for the utilization of more renewable sources of energy, photovoltaic panels have become one of the trending technologies which convert the energy from the sun to a useable electrical power. But …

Chemical Quantification With Ubiquitous Optoelectronic Devices, Altamash Mukhtar Fakki

Masters Theses

"Optical sensing in medical diagnosis and chemical analysis using optoelectronic devices is a growing technology since it offers many advantages including real time analysis, remote sensing capability and low cost approach. This thesis demonstrates that an optical sensing platform utilizing optical mouse, the ubiquitous optoelectronic computer peripheral, can be used in quantitative oxygen and pH analysis.

Work in the first paper includes the use of optical mice for fluorescence intensity imaging of commercial oxygen patch. This involves gray color intensity analysis of filtered images to determine the gaseous oxygen level.

In the second paper, the optical mice is used to …

Determination Of Setting Times By Shear Wave Velocity Evolution In Fresh Mortar Using Bender Element Method, Jianfeng Zhu

Masters Theses

This study aims at using modified bender element (BE) method to monitor the shear wave velocity (V_s) of mortar at early-age and determine initial and final setting times with the V_s method. Modifications of the traditional BE method have been made to overcome the aggressive cementitious environment and eliminate electromagnetic coupling. BE has been successfully employed in mortar samples with and without admixtures to evaluate the evolution of V_s during the early age (first 24 hrs) of hydration. An energy approach method of determining the first arrival time of S-wave has been proposed. Pulse wave velocity …