Digital Commons Network^™

Computation Of Power Plane Pair Inductance, Measurement Of Multiple Switching Current Components And Switching Current Measurement For Multiple Ics With An Island Structure, Liang Li

Masters Theses

"The first part of the thesis presents the computation of power / ground plane pair inductance based on Partial Element Equivalent Circuit (PEEC) method in power distribution network (PDN) design. An efficient approach for the inductance computation is investigated. Speed-up techniques are employed include using the faster decay of mutual coupling due to the "differential" currents (same magnitude but opposite directions) in the two planes. Also, an approximate rectangular mesh reduction method is introduced which allows a local increase in mesh density.

The second part presents a measurement-based data-processing approach to obtain parameters of multiple current components through a bulk …

A Feasibility Analysis Of Retrofitting Existing Roadway Lighting Infrastructure With Led Technology, Sean Michael Schmidt

Masters Theses

LED technology has advanced towards use in high intensity lighting purposes. LED luminaires have a significantly longer expected lifetime than traditional high-intensity discharge lighting systems. Due to these recent improvements in LED technology, there is a growing need for a comprehensive method to analyze the applicability of LED luminaires for use on major routes and roadways. This research investigates the acceptability of LED luminaires for use on major roadways through a feasibility analysis using data collected at various LED street light testing sites. Nine distinct LED luminaires were analyzed in field testing. The field data was then analyzed and compared …

Effect Of Side Edge Distance And Concrete Materials On Corrosion In Precast Prestressed Concrete Panels, Dayi Zhang

Masters Theses

"This study involved the spalling problem found in some partial-depth precast prestressed bridge decks in the state of Missouri. Recently, panels of several bridges have exhibited corrosion of the prestressing steel tendons causing concrete spalling at the edges of panels. Some of the exposed tendons are corroded to the point of rupture. The effect of factors, namely concrete side edge distance and concrete material type, on steel corrosion in chloride-contaminated reinforced concrete was investigated in this study. Wet-dry cycle tests and accelerated corrosion tests were carried out on sixty-three specimens designed with three different side edge distances and three different …

Laboratory Implementations Of Pmsm Drive In Hybrid Electric Vehicles Applications, Amir E. Saad

Masters Theses

"Field Programmable Gate Arrays (FPGAs) are one of the today's most successful technologies for developing systems that require real time operation and providing additional flexibility to the designer. This research is focused on developing a control board for a permanent magnet synchronous machine (PMSM) using an FPGA module. The board is configured for individual use of an FPGA, digital signal processor (DSP) or in combination to control the PMSM by generating the required Pulse Width Modulator (PWM) to the inverter in order to drive and control the speed of the PMSM. Since, the exact rotor position and speed are required …

Formation Of Amyloid Fibrils By Diblock Peptides, Kunal Mukesh Naik

Masters Theses

"The objective of this study was to identify and then synthesize a series of peptides which were able to form fibrils rich in ß-sheet structure and to study the effect of the presence of surfaces on their formation. We decided to focus our experimental work on a family of peptides containing one "beta-sheet forming amino acid" and one 'alpha-helix forming amino acid'. This selection covers a wide range of hydrophillicites and charges and, by avoiding highly hydrophobic amino acids we can assure that the diblock peptides are soluble in a wide range of concentrations and solvent conditions. Three different diblocks …

Forward Converter For Solar Power Applications, Nickolas Arthur Mcfowland

Masters Theses

"Most solar arrays used today are connected in series and have tremendous power losses in partially shaded conditions. This document explores photovoltaic arrays in a parallel connection to reduce the power losses in other solar cell connected applications. The two main issues with any photovoltaic arrays are solar modules being shaded and the efficiency of the power converters used within the solar array. This thesis concentrates on alleviating these problems with the development of a two phase dc to dc forward converter with a snubber circuit as well as connecting a solar array in parallel to increase the performance in …

Field Coupled Electrostatic Discharge Sensitivity Database, Zhen Li

Masters Theses

"Electrostatic Discharge (ESD) can disrupt the performance of an electronic system, like an MP3 player either by injected currents or by transient fields. It is possible to predict at least the approximate transient field levels inside a system, but it is difficult to determine the response of ICs subjected to these fields, as no IC specific data is available, and as it is often too involved to measure the sensitivity of every IC possibly used in a product. As deterministic solutions are difficult to achieve, a statistical approach has been selected in this research. The goal of this database for …

Numerical Investigation Of Second-Law Characteristics Of Ramjet Throttling, Jonathan Albert Sheldon

Masters Theses

"A numerical study of a generic axisymmetric ramjet operating at conditions corresponding to flight Mach 3.0 and a standard altitude of 10 km is presented. The study includes both modeling of steady-state flowfields in the ramjet as well as transient throttling maneuvers in which the throttle is decreased or increased from maximum or minimum throttle positions. The results presented here focus on entropy generation and performance characteristics. Combustion-generated exothermic heat release is modeled using simple volumetric energy addition to the flow within a defined heat release zone. The study utilizes two levels of wall boundary modeling, corresponding respectively to inviscid …

Enabling Frequency And Voltage Regulation In Microgrids Using Wind Power Plants, Anshuman Shrikant Vaidya

Masters Theses

"Renewable energy sources, like wind can be used to augment the grid-friendly services in the form of additional active and reactive power for control of frequency and voltage regulation. Currently, wind power systems are operated in simple energy supply mode and are not utilized to participate in ancillary power services. With the increase in the installed wind power capacity, limited conventional generation and increasing interest in microgrids, the necessity to implement regulation support from wind energy becomes critical. This thesis focuses on the effect of enabling frequency and voltage regulation capability in wind power plants in a microgrid environment. This …

Dynamic Model-Based Systems Engineering Using Xml Metadata Interchange, Dustin Scott Nottage

Masters Theses

"Designing systems presents an engineer with numerous design choices based on multiple conditions and constraints. Base camp planning must take into account the number of soldiers, the permanency of the base, the location of the base, etc. To help alleviate the complexity of constructing a base camp, a model-based systems engineering approach is used. This method creates and integrates models for all of the facilities that can make a base camp, as well as interactions between facilities and required utilities for each. The goal is to have a camp design, and then solve a system of equations to solve for …

Robust Evolutionary Algorithms, Brian Wesley Goldman

Masters Theses

"Evolutionary Algorithms (EAs) have shown great potential to solve complex real world problems, but their dependence on problem specific configuration in order to obtain high quality performance prevents EAs from achieving widespread use. While it is widely accepted that statically configuring an EA is already a complex problem, dynamic configuration of an EA is a combinatorially harder problem. Evidence provided here supports the claim that EAs achieve the best results when using dynamic configurations. By designing methods that automatically configure parts of an EA or by changing how EAs work to avoid configurable aspects, EAs can be made more robust, …

Design And Development Of Ionic Liquid Dual-Mode Spacecraft Propellants, Steven P. Berg

Masters Theses

"Energetic ionic liquids capable of dual-mode chemical monopropellant or bipropellant and electric electrospray rocket propulsion are investigated. Following an extensive literature review, ionic liquids [Bmim][dca], [Bmim][NO₃], and [Emim][EtSO₄] are selected for study since their physical properties align well with the current state-of-the-art in chemical and electrospray propellants. Simulations show that these liquids will not be useful for monopropellant propulsion due to the prediction of solid carbon formation in the exhaust and performance 13-23% below that of hydrazine. Considering these ionic liquids as a fuel component in a binary monopropellant mixture with hydroxyl ammonium nitrate shows 1-4% improved specific impulse over …

Numerical Investigation Of Plasma Actuator Configurations For Flow Separation Control At Multiple Angles Of Attack, Thomas Kelsey West Iv

Masters Theses

"The primary objective of the study presented in this thesis was to analyze the effectiveness of aerodynamic plasma actuators as a means of active flow control over a low speed airfoil at multiple angles of attack each corresponding to two different flow separation mechanisms (i.e., laminar separation bubble and turbulent flow separation at stall conditions). Detailed parametric studies based on steady and unsteady Navier-Stokes simulations, modified to include the body force term created by the plasma actuator, were performed for a NACA 0012 airfoil at a chord Reynolds number of 10⁵. In particular, parametric studies were performed to investigate the …

Ultrasonic Communications System For Health Monitoring Of Hydrokinetic Turbine Blades, Andrew James Heckman

Masters Theses

"A health monitoring approach is investigated for hydrokinetic turbine blade applications. In-service monitoring is critical due to the difficult environment for blade inspection and the cost of inspection downtime. Composite blade designs provide a medium for embedding sensors into the blades for in-situ health monitoring. The major challenge with in-situ health monitoring is transmission of sensor signals from the remote rotating reference frame of the blade to the system monitoring station. In the presented work, a novel system for relaying in-situ blade health measurements in hydrokinetic systems is described and demonstrated. An ultrasonic communication system is used to transmit health …

A Planning Tool To Predict The Welding Angle In Laser Metal Deposition, Sriram Prabhu

Masters Theses

"Research in Laser Metal Deposition (LMD) has been done rigorously in the past. However, the main challenge that still exists is the production of complex part geometries having overhang features. Production of such features requires individual tracks with a high aspect ratio and wider bead angle. The use of destructible/ non-destructible support structures involves costly post production operations which increase production cost. Tilting or moving the deposition surface can be useful to create overhangs but are applicable only to special cases. Since such techniques have to be used by the manufacturing community, the techniques need to be simple in calculation …

Plastic Strain Accommodation And Acoustic Emission During Melting Of Embedded Indium Particles In Aluminum, Michael M. Kuba

Masters Theses

"Melting of micron-sized (0.2 to 3 µm diameter) indium particles embedded in an aluminum matrix was discovered to produce acoustic emission. Melting of embedded immiscible particles produces a pure dilation during the phase transformation and has no long-range diffusion field to control the speed of transformation. It was found that acoustic emission can no longer be considered as a criterion of displacive transformations and that melting of micron-sized embedded particles is strain energy controlled. Acoustic emission was confirmed to result from the rapid relaxation of aluminum around indium particles embedded on grain boundaries. Prismatic punching of dislocation loops is proposed …

Maximum Power Point Tracking Control Of Hydrokinetic Turbine And Low-Speed High-Thrust Permanent Magnet Generator Design, Hailong Zhou

Masters Theses

"River-based hydrokinetic turbine power generation systems have been studied to introduce an effective energy flow control method. Hydrokinetic turbine systems share a lot of similarities with wind turbine systems in terms of physical principles of operation, electrical hardware, and variable speed capability for optimal energy extraction. A multipole permanent magnet synchronous generator is used to generate electric power because of its ability to reach high power density and high thrust at low speed. A 3-phase diode rectifier is used to convert AC power from the generator into DC power and a boost converter is used to implement energy flow control. …

Gray Gas Analysis Of Radiative Preheating Effects On Shock Induced Combustion, Pratibha Raghunandan

Masters Theses

"The use of detonations in combustors has been receiving increased attention in recent times. The presence of shock waves in such combustors invariably poses the existence of two domains that present different physics for the flow processes. The variation of upstream temperature due to radiative heating by the products of combustion was given particular attention in the present study. The modeling of heat transfer across a normal shock wave of negligible thickness was done by considering the reactants and the products of combustion to be in radiative equilibrium with each other. The quantification of emissivity of the products of combustion …

Hardened Mechanical Properties And Durability Performance Of Specialized Concretes, Kyle Richard Holman

Masters Theses

"Concrete is one of the most produced and utilized materials in the world. Due to the labor intensive and time consuming nature of concrete construction, new and innovative concrete mixes are being explored. Self-consolidating concrete (SCC) is one such method of improving the overall cost and time efficiency of concrete production. SCC is a highly flowable form of concrete. This characteristic drastically reduces the amount of labor and time needed to place the concrete. The highly flowable nature also allows for much easier placement in applications of highly congested reinforcement.

Another rising concern in today's construction industry is environmental responsibility. …

A Three-Dimensional Transient Simulation Of An Electrochemical Magnetohydrodynamics Cell With Micro And Millielectrode: A Unified Reconciliation Of Theory And Experiment, Cajon Gonzales

Masters Theses

"Even though electrochemically induced magnetohydrodynamic (MHD) convection is a straightforward inexpensive method for moving fluids in confined spaces as for example during electrodeposition, stripping voltammetry, or in microfluidics, efficient quantitative models only recently have begun to appear. This is traced to complex mathematics that have prevented development of analytical expressions, e.g., for mass-transfer limited currents in analogy to the well-known Levich equation for the rotating electrode. Thus, related literature expressions remain mainly phenomenological concerning particular cell geometries or applications. Here, using such reports as points of departure, we validate a computationally rigorous description of the magnetoelectrochemical problem and define the …

Impact Of Interruptions In White Collar Working Environment, Zafar Akhil Khan

Masters Theses

"An interruption is a randomly occurring, discrete event that breaks continuity of cognitive focuses on a primary task and typically requires immediate attention and insists on action. "White collar interruptions" are those that affect knowledge workers in professional, managerial, or administrative positions. Interruptions are often a common occurrence in the white collar workplace.

The aim of this thesis is to investigate the effect of timing of an interruption on the overall performance of white collar workers. This study also analyzes the interruption sources (i.e. externally and internally generated) along with effect of different types of interruptions on both demanding and …

Prototyping And Testing Of Solar Hybrid Pv-T Panels, Joel Aaron Lamson

Masters Theses

"The combination of photovoltaic and solar thermal (PV-t) systems has been proven to provide greater efficiency than their stand-alone counterparts. Previous studies on hybrid assemblies have found favorable results supporting the combination of both systems. The research presented here builds on the work competed here at Missouri University of Science and Technology (Missouri S&T) yielding favorable results of increased efficiencies as compared to stand-alone systems. The main difference between this experiment and previous research at Missouri S&T is that the hybrid PV-t is unglazed. The effect of an unglazed panel is shown to reduce the thermal output of the PV-t …

Cerium-Based Conversion Coatings On Cast Aluminum 380 And 413 Alloys, Ci Lin

Masters Theses

"This investigation focused on the deposition and characterization of cerium-based conversion coatings (CeCCs) on cast aluminum alloys. Previous research has shown that CeCCs are viable alternatives to chromate conversion on high strength alloys such as 2024-T3 and 7075-T6. For the casting alloys such as 380 and 413, the presence of Si affects the composition and stability of the native oxide, which means that pretreatment plays an important role for the coating deposition. This thesis consists of two papers that describe the results of the study.

The first paper reports the effect of the final rinsing temperature before coating deposition on …

Analyses Of Surface Wave Seismic Data And Supplemental Borehole And Electrical Resistivity Tomography Control, Mengxing Li

Masters Theses

"Multichannel analyses of surface wave (MASW) data and electrical resistivity tomography (ERT) control were acquired at two test sites in central Missouri. Limestone bedrock existed at both test sites at variable depths. The ground surface at both test sites was relatively flat.

The primary objective was to map the variable depth to the top of the rock based on shear-wave velocity contrasts. ERT data and borehole control were acquired at each site in order to constrain the interpretation of the MASW data.

The MASW method proved to be more effective than the ERT method in terms of mapping soil layers …

Modeling Supply Chain Network Resiliency In The Aftermath Of An Extreme Event, Varun Ramachandran

Masters Theses

"Failure of infrastructure elements due to an extreme event adversely affects the supply chain networks in any urban environment. This study models the resiliency of a supply chain network by integrating geospatial data with critical supply chain elements and graph theory. This model can then be combined with an extreme event simulation to calculate resiliency. Resiliency refers to the time required for services and select economic indicators to approach pre-event levels (in this study, a return to 80% of the pre-event capacity). This research proposes an interdisciplinary approach to develop a comprehensive framework for resiliency modeling. This approach includes the …

Studies Of Inductive Plasmas And Their Application To Theta-Pinch Devices Via Numerical Modeling, Warner C. Meeks

Masters Theses

"First, a globally-averaged RF plasma model is used to investigate exit conditions immediately following a RF pre-ionization stage. Analysis shows that reducing pulse duration from 10⁻⁶ to 10⁻⁷ seconds increases peak ion energy fraction by 17% (from 16 to 33%) and doubles final conductivity. Pulse waveforms are square in nature, and ion energy fraction is defined in this work as the percentage of total input energy entrained in ions. Increasing total energy deposition from 5 to 160 mJ increases ion energy fraction from 33% to 58% at a 200 ns pulse duration. This increase is not linear however, showing instead …

Implementation And Evaluation Of Spatial Audio Recording And Rendering Techniques, Jayasecha Raghavendra Nimmala

Masters Theses

"The thesis is divided into two main sections. First half describes the implementation of different adaptive beamforming techniques. Adaptive beamforming techniques are widely used in many real world applications like teleconferencing, speech recognition, devices for the hearing impaired, radar, sonar, etc. The beamformer is an array of sensors which can be electronically steered to any particular direction to enhance the signal in the direction of interest while at the same time suppressing interference or jammers coming from other directions.

In our experiment, we implement both the regularized minimum variance distortionless receiver (MVDR) and the generalized sidelobe canceller (GSC). The beamforming …

Energy Efficiency In Wastewater Treatment: Standards For Missouri Facilities, Samantha Lauren Markus

Masters Theses

"Traditionally, energy has been used to treat wastewater. As energy costs rise, so does the financial burden on communities with municipal wastewater treatment plants (WWTP). Determining energy efficiency of small to mid-sized plants is difficult because these plants are the least likely to have the resources to conduct an energy audit and the most likely to be overlooked in national models due to their small contribution to the national energy burden. Data was gathered via personal contact the WWTPs in Missouri and from this data metrics fro comparison were developed. The data was also compared to the predicted energy use …

Microlens Array Light Trapping In Cdte/Cds Solar Cells, Patrick Michael Margavio

Masters Theses

"In light of the continued rise in fossil fuel costs, alternative energy sources, such as solar technology, are increasingly important. Concentrating photovoltaic systems are promising for future efficient and cost effective competition with fossil fuels. A microlens array is employed to a CdTe/CdS semiconducting solar cell to increase efficiency via light trapping. Since the microlens array will cause a local increase in incident light intensity, it should cause a corresponding increase in efficiency. The solar cell is deposited layer by layer. The CdS layer is chemically deposited. The CdTe layer is deposited using a novel additive manufacture technique: laser melting …

Information Theoretic Analysis And Design Of Passive Wireless Backscatter Sensor Networks, Aditya V. Padaki

Masters Theses

"Passive, backscatter-based communication technology is increasingly employed in wireless sensing applications. It offers several advantages including small form factor, battery-less operation, increased system lifetime, small configurations, etc. The main focus of this work is to study the theoretical limits of the network performance in such passive sensor networks. In addition to the traditional direct communication between an active and several passive devices (like RFID), the information theoretic analysis considers two new communication frameworks: multi-hop and multipath passive networks. These new frameworks are demonstrated through theoretical and simulation results to improve the network performance and fairness over the traditional direct communication. …