Digital Commons Network^™

An Imu-Based Spacecraft Navigation Architecture Using A Robust Multi-Sensor Fault Detection Scheme, Samuel J. Haberberger

Masters Theses

"Redundant sensor networks of inertial measurement units (IMUs) provide inherent robustness and redundancy to a navigation solution obtained by dead reckoning the fused accelerations and angular velocities sensed by the IMU. However, IMUs have been known to experience faults risking catastrophic mission failure creating large financial setbacks and an increased risk of human safety. Different fusion methods are analyzed for a multi-sensor network using cost effective IMUs, including direct averaging and covariance intersection. Simulations of a spacecraft in low Earth orbit are used to baseline a typical expensive IMU and compare the navigation solution obtained from a network of several …

The Mantle Transition Zone Beneath South America From Stacking Of P-To-S Receiver Functions, B. A. Goetze

Masters Theses

"The Mantle Transition Zone (MTZ) beneath South America is investigated with stacking of Receiver Functions (RFs) of converted P-to-S phases from the velocity discontinuities at 410 km (d410) and 660 km (d660). A total of 785 seismic stations provided 22,235 high quality RFs, allowing 1,717 MTZ thickness measurements in circular bins of 2⁰ radius. An apparent MTZ structure is derived using the IASP91 reference model, where the d410 mean depth is 409.1 km and the d660 is 661.5 km, and the mean MTZ thickness is 251.8 km. This model presents coherent depressions and uplifts of the discontinuities matching well known …

Imaging Reinforced Concrete: A Comparative Study Of Ground Penetration Radar And Rebarscope, Abhishek Kodi

Masters Theses

"Geophysical techniques have been playing a very vital role in subsurface imaging in the recent past. Technology has been making it both reliable and convenient to utilize non-destructive geophysics techniques like Ground Penetration Radar, Induction current based Rebarscope, Seismic methods, ERT, etc. The applications range from shallow subsurface investigation of Bridge decks to old tunnels, mapping of rabars in a pre-existing construction and analyzing the concrete strength.

The thesis constitutes of a comparative study and analysis of a Ground Penetration Radar system and a Rebarscope. Individual parameters obtained directly from the study and obtained indirectly from the study shall be …

Silicone Hollow Fiber Membrane Bioreactors For Mixed Aerobic And Anaerobic Treatment Of Gas Phase Toluene And Trichloroethylene, Alexander Lee Korff

Masters Theses

"Volatile Organic Compounds (VOCs) are common in effluent waste streams from many sectors of industry and low-cost emission control technologies have the potential to mitigate long-term impacts on the environment. Federal Regulations, such as the Clean Air Act and National Emission Standards for Hazardous Air Pollutants (NESHAPS), as well as state regulations are imposing stricter requirements on point-source emissions, with an emphasis on toxic VOCs. Trichloroethylene (TCE) and tetrachloroethylene (PCE), which are toxic VOCs, have been used since the 1920's for a variety of industrial applications like: degreasing, paint and printing operations, as extraction solvents, and for cleaning and drying …

Iron Phosphide Nanostructures As An Efficient Bifunctional Catalysts For Water Splitting, Nikitaa Ashokan

Masters Theses

"The first part of this thesis work focuses on developing a bifunctional catalyst for electrochemical water splitting encompassing both oxygen and hydrogen evolution. A highly efficient catalyst is necessary to improve kinetics of the sluggish four electron process for oxygen evolution reaction (OER) and two-electron process for hydrogen evolution reaction (HER). Recently, transition metal phosphides have gained increasing interest in this field because of their good electrical conductivity properties as well as better catalytic activity. Many transition-metal phosphides are being considered for this application and iron phosphide (FeP) has proved to be a good HER catalyst. In this work, we …

A Meta-Architecture Analysis For A Coevolved System-Of-Systems, George Anthony Muller Iv

Masters Theses

"Modern engineered systems are becoming increasingly complex. This is driven in part by an increase in the use of systems-of-systems and network-centric concepts to improve system performance. The growth of systems-of-systems allows stakeholders to achieve improved performance, but also presents new challenges due to increased complexity. These challenges include managing the integration of asynchronously developed systems and assessing SoS performance in uncertain environments.

Many modern systems-of-systems must adapt to operating environment changes to maintain or improve performance. Coevolution is the result of the system and the environment adapting to changes in each other to obtain a performance advantage. The complexity …

Effect Of Sparse-Build Internal Structure On Performance Of Fused Deposition Modeling Parts, Shixuan Meng

Masters Theses

"Fused deposition modeling (FDM) technology has been used in additive manufacturing for years and is able to significantly reduce both manufacturing time and cost for production tooling and end-use parts. Autoclave molding is one of the conventional tools used to produce composite parts. In autoclave molding, the soft composite material is positioned on the molding tool, and then subjected to vacuum and elevated temperatures to facilitate the curing of the resin. With additive manufacturing (AM), it is possible to fabricate the molding tool with a sparse internal structure, thereby reducing the fabrication time and cost compared to a solid tool. …

The Impact Of Heat Exchanging Internals On Hydrodynamics Of Bubble Column Reactor, Ahmed Jasim

Masters Theses

"In this study, the impact of configuration and size of vertical heat exchanging internals in bubble columns on gas holdup, specific gas-liquid interfacial area, bubble chord length, and bubble rise velocity were investigated. Three different configurations of internals, each covering 25% of the column's cross-sectional area, were used to simulate the heat exchanging tubes utilized in the F-T process. The First configuration is a circular-like arrangement of 0.5 inch diameter vertical rods, whereas the second is a hexagonal-like arrangement of 0.5 inch diameter vertical rods. The third configuration is also a circular arrangement but of 1 inch diameter vertical rods …

Effect Of Build Parameters On Mechanical Properties Of Ultem 9085 Parts By Fused Deposition Modeling, Krishna Prasanth Motaparti

Masters Theses

"Additive manufacturing is a fabrication technique that is used to build components by depositing material in a layer-by-layer manner. Fused Deposition Modeling (FDM) is one of the additive manufacturing techniques which is widely used for prototyping and production applications of thermoplastic components. In load bearing applications, the flexural and compression forces often coexist. In order to avoid failure under these loads, it is essential to study the mechanical properties of the components fabricated by FDM. The main focus of this research is to study the mechanical properties of the fabricated components and to comprehend their dependence on various build parameters. …

Yik Yak Posts: A Discourse Analysis, Snehal Ravindra Shirke

Masters Theses

"Anonymity and geolocation create a unique environment for users to communicate with each other. Discourse analysis was conducted to study the posts made on Yik Yak, an anonymous social networking mobile application to understand the communication patterns on an anonymous platform and the posts about taboo topics. The posts were analyzed specifically for patterns on taboo topics and how students interact on the anonymous platform on a particular campus (Missouri S&T campus). Student research assistants coded the collected posts into the pre-defined taboo categories namely sexual activity, non-sexual bodily functions, sexual orientation, mental/emotional health, and "other" taboo topics. I found …

Esd Related Soft Error Detection And Root Cause Analysis, Suyu Yang

Masters Theses

"In this article, several methods are outlined for detecting functional changes in an IC due to external interference such as ESD or EMI. The goal is to provide diagnostic tools for detection of potential soft failure susceptibilities of complex systems during the hardware design stage without the aid of any complex software. After the soft errors are found, circuit modeling techniques are used to characterize the DUT. By running the circuit model, the soft error threshold can be predicted and the circuit model can be used to evaluate the performance of other ESD protection methods. In the end several methods …

Variable Stress Orientations In The Offshore Nile Delta: The Role Of Salt As A Mechanical Detachment Horizon, Weicheng Zhang

Masters Theses

"The offshore Nile Delta is characterized by variations of the maximum horizontal stress orientation in subsalt and supra-salt sequences. Margin-parallel SH, typical for tertiary deltas, is observed for regions that are below or do not contain evaporites. In sequences underlain by evaporates pre-dominantly margin-normal SH is observed. This observation yielded the first conclusive in situ evidence that salt acts as a mechanical detachment layer. In this study, 3D finite element analysis (FEA) is used to simulate the total stress distribution in the offshore Nile Delta featuring evaporate sequences. Several parameters such as different salt sequence geometries, friction coefficient on faults, …

Automated Channel Emulator Based On Mems Switch And Improvement Of Signal Transition, Jingdong Sun

Masters Theses

"Channel Emulator, which is widely used in communication system development, is an instrument that emulates the real-world signal propagation environment between transmitter and. [sic] To overcome the disadvantages of traditional channel emulator, we propose a novel structure of the automated channel emulator in Section 1, which can be controlled by software and integrated into auto-testing system. MEMS switch, with good RF performance, is used to connect and isolate multiple channels.

In Section 2, we divide the whole channel emulator system into Channel, Support, and Controller Board, and provide detailed design procedures with critical parameters of each board. The well-designed high …

Reprocessing And Structural Interpretation Of Multichannel Seismic Reflection Data From Penobscot, Nova Scotia, Fulya Gizem Yagci

Masters Theses

"Penobscot area is located in the Scotian Basin, which was occurred as a result of extension in the eastern North America border. 2-D data set that was utilized for the study consists of three multichannel seismic profiles that were collected from Penobscot Parcel 8. The main purpose of the study was to enhance signal-to-noise ratio of the seismic reflection sections suppressing high frequency noise and multiples, and removing diffractions. In addition, while the resolution of the sections were enhanced, determining the correct processing techniques and parameters for better results was the another important criteria.

The processing steps included deconvolution, minimum …

Effect Of Reservoirs Heterogeneity On Injection Pressure And Placement Of Preformed Particle Gel For Conformance Control, Ze Wang

Masters Theses

"Preformed particle gels (PPG) have been successfully applied as a plugging agent for plugging fractures and then divert displacing fluid into poorly swept zones. However, PPG propagation and plugging mechanisms through open fractures have not been studied thoroughly.

This work investigated the influence of some factors (particle size, brine concentration, heterogeneity, and brine salinity) on gel injectivity, plugging performance for water flow through open fractures. Five-foot tubes were used to mimic open fractures. Three models were designed to conduct the work, including (1) single fracture with uniform fracture width, (2) single fracture with different widths, and (3) two parallel fractures …

Study On The Applicability Of Relative Permeability Modifiers For Water Shutoff Using Numerical Simulation, Dheiaa Khafief Khashan Alfarge

Masters Theses

"Water production is a challenging problem to be controlled during hydrocarbon-reservoirs production life. Disproportionate Permeability Reduction (DPR) is often used as water shutoff treatment in production wells when other conventional solutions like mechanical isolations are difficult to perform. This study applied numerical simulation methods to diagnose the factors impacting DPR treatment success on macroscopic level and to see when, where and at which conditions DPR treatment can give best results.

This work indicated that the following points should be considered before DPR treatment is executed in any reservoir to get a successful treatment. Firstly, this research explored that DPR performance …

Prediction Of Surface Roughness In Abrasive Waterjet Cutting Of Graphite Composite Using Response Surface Methodology, Prabhakar Bala

Masters Theses

"In the present work, surface roughness after machining of composite material was the main focus of study. Response surface methodology with Box- Behnken experimental design was applied in predicting the surface roughness (R_a) of abrasive waterjet cut 1-inch-thick graphite/epoxy composite. Second order response equations for R_a were generated with minitab, a statistical software as a function of pressure, traverse speed and isolated abrasive mesh size. Influence of each of these factors on the response were analyzed with 3D response surface plots. Abrasive mesh size was also found be a factor influencing Ra along with traverse speed and …

A Control Algorithm For The Solar Village Microgrid System, Hamad Ahmed Alharkan

Masters Theses

"In this thesis, the concept of microgrid system is introduced. Also, the major components of a microgrid will be discussed thoroughly. Both grid-connected and autonomous modes are explained. In addition, the control of a microgrid is defined for the following types: local, centralized and decentralized control.

As one of the nation's premiere research universities, the Missouri University of Science and Technology has built four inspirational solar houses (solar villages) for a competition in the US Department of Energy Solar Decathlon to allow students to research and improve different aspects of the microgrid system. Consequently, this thesis develops a computer model …

Mixing Dynamics In Municipal Water Storage Tanks, Pramod Narayan Bangalore

Masters Theses

"The purpose of this study is to investigate the effects of different control variables on mixing in municipal water storage tanks using Computational Fluid Dynamics(CFD) solutions with ANSYS FLUENT for isothermal, positively and negatively buoyant inflow conditions. Poor mixing of old water and new water leads to dead zone formation, which when introduced in the distribution system can cause major water quality issues. Data for this study was generated using Multiphase CFD flow modeling technique using Volume of Fluid (VOF) approach with species transport. The vessel was considered to be mixed when Coefficient of Variation (COV) dropped below 0.10.

Results …

3d Seismic Structural And Stratigraphic Interpretation Of The Tui-3d Field, Taranaki Basin, New Zealand, Gorkem Yagci

Masters Theses

"Identifying seismic structures and stratigraphy are important for exploration of hydrocarbons. The purpose of this study is to discover seismic structural and stratigraphic features and to utilize the results for interpreting depositional environments. A 3D seismic dataset from the Tui-3D Field, the Taranaki Basin, New Zealand with well data were used to visualize structures, to detect stratigraphic features, to identify main lithology, to understand depositional environment, and to describe seismic facies and reflection patterns of the target horizons. The major formations are in the Kapuni Group.

Seismic structural interpretation indicates thirty-two minor faults, which may play an important role in …

Attenuation Properties Of Cement Composites: Experimental Measurements And Monte Carlo Calculations, Raul Florez

Masters Theses

"Developing new cement based materials with excellent mechanical and attenuation properties is critically important for both medical and nuclear power industries. Concrete continues to be the primary choice material for the shielding of gamma and neutron radiation in facilities such as nuclear reactors, nuclear waste repositories, spent nuclear fuel pools, heavy particle radiotherapy rooms, particles accelerators, among others. The purpose of this research was to manufacture cement pastes modified with magnetite and samarium oxide and evaluate the feasibility of utilizing them for shielding of gamma and neutron radiation. Two different experiments were conducted to accomplish these goals. In the first …

Thrust Sensing For Small Uavs, Christopher Scott Marchman

Masters Theses

"Unmanned aerial vehicles (UAVs) have become prevalent in both military and civilian applications. UAVs have many size categories from large-scale aircraft to micro air vehicles. The performance, health, and efficiency for UAVs of smaller sizes can be difficult to assess and few associated instrumentation systems have been developed. Thrust measurements on the ground can characterize systems especially when combined with simultaneous motor power measurements. This thesis demonstrates the use of strain measurements to measure the thrust produced by motor/propeller combinations for such small UAVs. A full-bridge Wheatstone circuit and electrical resistance strain gauges were used in conjunction with constant-stress cantilever …

Structural Analysis And Fluid Flow Modeling Of The Kapuni Field, New Zealand, Jarret Taylor Baldwin

Masters Theses

"The Taranaki Basin is the largest hydrocarbon producing basin in New Zealand. A total area of over 330,000 km

Deterministic Simulation Of Thermal Neutron Radiography And Tomography, Rajarshi Pal Chowdhury

Masters Theses

"In recent years, thermal neutron radiography and tomography have gained much attention as one of the nondestructive testing methods. However, the application of thermal neutron radiography and tomography hindered by their technical complexity, radiation shielding, and time-consuming data collection processes. Monte Carlo simulations have been developed in the past to improve the neutron imaging facility's ability. In this present work, a new deterministic simulation approach has been proposed and demonstrated to simulate neutron radiographs numerically using a ray tracing algorithm. This approach has made the simulation of neutron radiographs much faster than by previously used stochastic methods (i.e Monte Carlo …

Design Of A Microwave Imaging System For Rapid Wideband Imaging, Matthew Jared Horst

Masters Theses

An imaging system composed of two linear arrays of antennas is designed through full-wave simulation and fabricated for use in synthetic aperture radar imaging. The arrays electronically scan along their antenna elements and are mechanically moved along a second orthogonal direction for scanning large two-dimensional areas quickly. Each linear array is printed on a circuit board where the antenna elements are integrated into the edge of the board as tapered slot-line antennas operating at 22 to 27 GHz. A multiplexer circuit is printed onto each linear array to transmit wideband signals to each antenna in the array. Receivers are printed …

Influence Of Mix Design Parameters On Dynamic Segregation Of Self-Consolidating Concrete And Consequences On Performance Of Precast Beams, Aida Margarita Ley Hernandez

Masters Theses

"Self-Consolidating Concrete (SCC) is more vulnerable to stability problems as a consequence of its high flowing ability compared to conventional vibrated concrete. Dynamic segregation refers to the tendency of the concrete constituents to separate from the suspended matrix, usually in horizontal direction while being cast into the formwork or due to an impact. Similarly to static segregation, dynamic segregation can affect the homogeneity of SCC. Therefore, it is highly essential to ensure a proper dynamic stability in order to enhance the uniformity of in-situ properties of pre-stressed beams.

In this research project, the effects of SCC mix design parameters are …

Developing An Idealistic Model To Characterize And Optimize A Photovoltaic Battery Systems, Pavani Reddy Nalladimmu

Masters Theses

"Solar energy is one of the most abundant and clean energy sources of renewable energy. Due to its unsteady nature, most photovoltaic systems require a solar storage system. Ultracapacitors have proven to be an effective solar energy storage component due to their wide range of input voltages and high power density. This research focuses on characterizing the performance of a PV/UCAP hybrid storage system to meet required household loads at various locations throughout the US as a backup energy source. A calibrated empirical model was developed to characterize system performance. A load profile was designed based on a typical 2 …

Intensity Control Of Dielectric Barrier Discharge Filaments, Matthew Crawford Paliwoda

Masters Theses

"When operated in a filamentary mode, a volume dielectric barrier discharge (DBD) is known to produce patterned plasma structures. These structures are currently being explored for reconfigurable metamaterial applications. In this work the presence and intensity of a single filament, within an array of filaments, was controlled by adjusting the voltage to that filament's individual needle electrode. The current, voltage, and time-averaged normalized light intensity were measured while varying the voltage of the needle through a self-biasing resistance. For a 7.5 kV, 3.2 kHz DBD in air, the needle-controlled filament intensity varies from that of the surrounding filaments to zero …

De-Embedding Method For Electrical Response Extraction Of Through-Silicon Via (Tsv) In Silicon Interposer Technology And Signal Integrity Performance Comparison With Embedded Multi-Die Interconnect Bridge (Emib) Technology, Qian Wang

Masters Theses

"Traditional two-dimensional system-in-package (2D SiP) can no longer support the scaling of size, power, bandwidth, and cost at the same rate required by Moore's Law. Three-dimensional integrated circuits (3D-ICs), 2.5D silicon interposer technology in which through silicon vias are widely used, are implemented to meet these challenges. Embedded multi-die interconnect bridge (EMIB) technology are proposed as well.

In Section 1, a novel de-embedding method is proposed for TSV characterization by using a set of simple yet efficient test patterns. Full wave models and corresponding equivalent circuits are provided to explain the electrical performance of the test patterns clearly. Furthermore, broadband …

Mixed Metal Oxide Catalysts Supported On H-Beta For Hydrogenolysis Of Glycerol Into 1,3-Propanediol, Amit Kant

Masters Theses

"Bioglycerol is the by-product which is produced largely from the microbial fermentation, hydrogenolysis of glucose in the mixture of polyols, fatty ester, soap manufacturing process and fatty acid production. Hydrogenolysis of glycerol is one of the most promising ways to convert glycerol and many work has been done towards 1,3-propanediol, 1,2-propanediol and 1-propanol using various metals and mixed-metal oxides such as W, Ru, Rh, Pt, Pd, Cu, Ni and different zeolites have been extensively used as the active components.

It has been well documented that the presence of Bronsted acid sites leads to the formation of acrolein, while Lewis acid …