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Theses/Dissertations

Missouri University of Science and Technology

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Full-Text Articles in Engineering

Improving Base Metal Electrowinning, Charles Ebenezer Abbey Jan 2019

Improving Base Metal Electrowinning, Charles Ebenezer Abbey

Doctoral Dissertations

"In zinc electrowinning, Mn oxidizes to form MnO2 on Pb-Ag anodes, cell walls and pipes. MnO2 reduces anode corrosion but also leads to short circuits and maintenance issues. MnO2 is thought to interact with chloride ions and produce oxidized chlorine species. The interactions between Mn and Cl are not well understood. Bench scale experiments were conducted to investigate the effects of the manganese to chloride ratio on anode corrosion rate and electrolyte chemistry using rolled Pb-Ag anodes. Increasing the average Mn/Cl- ratio from ~7:1 to ~11:1 reduced the anode corrosion rate. Anode scales produced ...


The Effects Of Low Aspect Ratio And Heat Exchanging Internals On The Bubble Properties And Flow Regime In A Pilot-Plant Bubble/Slurry Bubble Column For Fischer-Tropsch Synthesis, Hayder Al-Naseri Jan 2019

The Effects Of Low Aspect Ratio And Heat Exchanging Internals On The Bubble Properties And Flow Regime In A Pilot-Plant Bubble/Slurry Bubble Column For Fischer-Tropsch Synthesis, Hayder Al-Naseri

Doctoral Dissertations

"Fischer-Tropsch synthesis (F-T) is a process utilized to convert the syngas mixture of CO and H2 to synthetic fuel and chemicals that executed commercially by using the bubble/slurry bubble column reactor. The experimental results reveal that the investigated parameters, in terms the presence of internals, and reducing the aspect ratio and the solids loading, increase the local gas holdup, interfacial area, bubble passage frequency, and decrease the bubble rise velocity, bubble chord length. Meanwhile, the aspect ratio H/D = 4, and 5 provide enough height to established the fully developed flow regime. As a result of the variation ...


Removal Of Antimony And Bismuth From Copper Electrorefining Electrolyte By Two Proprietary Solvent Extraction Extractants, Andrew Artzer Jan 2019

Removal Of Antimony And Bismuth From Copper Electrorefining Electrolyte By Two Proprietary Solvent Extraction Extractants, Andrew Artzer

Masters Theses

"Antimony and bismuth are two of the most problematic impurities in copper electrorefining (ER). Because of this, much research has been done investigating the ways to remove them. Processes that are currently being used industrially include anode additions, liberators, ion exchange (IX), and solvent extraction (SX). Of these, liberators and anode additions are the most common while SX is the least, mostly being used for arsenic removal. There are other methods that have been evaluated, but are not in commercial use. These include the use of various electrolyte additives, and adsorbents such as bentonite clay and heavy metal sulfates.

Two ...


Unified Probe Launch Pattern Design And Methodology Of Differential Probe Characterization, Han Deng Jan 2019

Unified Probe Launch Pattern Design And Methodology Of Differential Probe Characterization, Han Deng

Masters Theses

"Differential probe is wildly used in the signal integrity area to do the accuracy signal measurement in frequency domain or time domain. Comparing with traditional SMA connector measurement, the probe measurement has several advantages such as the high flexibility and measurement efficiency. Nevertheless, the probe has some disadvantages such as multiple design patterns and the difficulty of fast landing. In this thesis, a unified probe landing pattern is provided to solve the con of probes and a probe testing fixture is designed for characterize probe and extract the probe model.

In the first portion, a unified differential probe launching pattern ...


Microwave Detection Of Surface Breaking Cracks In Metallic Structures Under Heavy Corrosion And Paint, John Robert Gallion Jan 2019

Microwave Detection Of Surface Breaking Cracks In Metallic Structures Under Heavy Corrosion And Paint, John Robert Gallion

Masters Theses

"We live in the world of "aging infrastructures". In this environment, critical and heavily utilized infrastructure, i.e. ships, planes, bridges, etc., are operating at or beyond their designed age. Replacement is no longer an option and "retirement for cause" is the current approach to maintenance and replacement. Consequently, there is an ever-increasing demand for efficient and robust nondestructive evaluation (NDE) methods that can determine the physical health of these structures. Large structures, which are primarily made of metals, either steel or aluminum, are susceptible to high-stress cracking and corrosion. Stress-induced cracks in heavily corroded steel, used in bridges, railroads ...


High-Speed Pcb Trace Design Using A Behavioral Surface Roughness Model And High-Speed Test Coupon Design With Non-Functional Pads, Han Gao Jan 2019

High-Speed Pcb Trace Design Using A Behavioral Surface Roughness Model And High-Speed Test Coupon Design With Non-Functional Pads, Han Gao

Masters Theses

"In high-speed digital systems as data rates increase to tens of gigabits per second, the loss from the conductor surface roughness cannot be ignored. Djordjeic and Huray roughness model is widely used to count for the conductor roughness loss. However the practical application of the existed models are not straight forward since the frequency-dependent dielectric loss is usually unknown, leading to high discrepancies at high frequencies (above 10 GHz). To solve this problem, a behavioral model was developed by adding a dispersive term to the dielectric. The dispersive term in the model captures dispersion behavior observed in the measurement accurately ...


Diffusion Kinetics In Promising Adsorbents For Gas Capture Processes, Teresa Gelles Jan 2019

Diffusion Kinetics In Promising Adsorbents For Gas Capture Processes, Teresa Gelles

Masters Theses

"This reports the results of experimental studies aimed at characterizing the transport properties of promising adsorbents for various gas capture processes by the "zero length column" (ZLC) technique. ZLC was used to measure the intracrystalline diffusivities of single and binary components of ethane and ethylene in powder and pellet samples of paraffin-selective adsorbents Ni(bdc)(ted)0.5 (Ni-BT) and ZIF-7 for the purpose of olefin/paraffin separation. Results show that binary gaseous systems result in intracrystalline diffusion time constants slightly lower than those in single component gaseous streams due to coadsorption effects. It was also found that ethylene diffusion ...


Investigating The Use Of Class C Flyash-Based Geopolymer Cement As A Potential Alternative To Portland Cement To Seal Co₂ Storage Wells, Priyesh Parimal Jani Jan 2019

Investigating The Use Of Class C Flyash-Based Geopolymer Cement As A Potential Alternative To Portland Cement To Seal Co₂ Storage Wells, Priyesh Parimal Jani

Masters Theses

"Capturing emitted carbon dioxide from the source of emission and storing it underground is one effective way to reduce the amount of CO2 in the atmosphere and is called carbon capture and storage (CCS). For the successful CCS project, it is necessary to ensure long term storage of injected CO2 inside these selected reservoirs. Portland cement used to cast wells in these reservoirs degrade in CO2 environment and can create migration path for leakage of CO2. The aim of this study was to provide a comprehensive review about the problem, to propose a new geopolymer cement ...


A Study On End-Anchorage And Bond Behavior Of Steel-Fiber Reinforced Cementitious Matrix Composites Externally Bonded To A Concrete Substrate, Christopher Michael Moore Jan 2019

A Study On End-Anchorage And Bond Behavior Of Steel-Fiber Reinforced Cementitious Matrix Composites Externally Bonded To A Concrete Substrate, Christopher Michael Moore

Masters Theses

"Fiber reinforced cementitious matrix (FRCM) composites are a strengthening material consisting of continuous fibers embedded in an inorganic matrix that have the potential to provide additional flexural and shear strength to concrete and masonry members. When used for external strengthening, however, debonding of the material is often observed due to slippage of the fiber with respect to the matrix, causing loss of composite action and a reduction in load carrying capacity. The composite utilized in this study consisted of continuous steel fibers embedded in an inorganic cementitious matrix bonded to a concrete prism. Additionally, an end-anchorage system was implemented with ...


Effects Of Uncertainty Refinement On Satellite Collision Probability, Bruce Thomas Morrison Jan 2019

Effects Of Uncertainty Refinement On Satellite Collision Probability, Bruce Thomas Morrison

Masters Theses

"Due to the drastic increase in orbital debris about the Earth, the likelihood for new and current mission satellites to collide with other objects grows. When a mission satellite is placed in a highly populated orbit in the vicinity of other satellites or debris, it is necessary to consider the probability of collision to assess any possible conjunctions. The computation of the collision probability is heavily dependent on the relative position and velocity of the objects during conjunction, as well as the combined covariance. There are two main types of analytic collision probability computations; the first assumes that the objects ...


Radiation Immunity In Cable Harnesses And Differential P/N Skew In Pcb, David Nozadze Jan 2019

Radiation Immunity In Cable Harnesses And Differential P/N Skew In Pcb, David Nozadze

Masters Theses

"We develop an efficient method to model RF immunity of multiwire cable harnesses and study differential P/N skew effects on channels, channel performance and specifically on the eye diagrams at the SerDes receiver.

External radiation can induce unwanted signals in transmission lines. For example, external radiation from an antenna induces common-mode currents on the outer surface of cable shields. This common-mode signal makes its way through the shied due to its imperfections, inducing the inner common mode. When twisted pairs inside the cable are not balanced, inner common mode is in turn converted to the differential mode, which might ...


Evaluation Of Naturally Occurring And Anthropogenic Contamination In Missouri Streams, Christina Jane Sehrt Jan 2019

Evaluation Of Naturally Occurring And Anthropogenic Contamination In Missouri Streams, Christina Jane Sehrt

Masters Theses

"The goal of this study is to observe the values and variability of water quality parameters and benthic macroinvertebrates in watersheds with very little anthropogenic impact and to compare these values with those acquired in watersheds with more anthropogenic impact. The following five HUC 12-digit watersheds had very little anthropogenic impact and were considered "pristine": Rogers Creek, Mill Creek, Middle West Fork-Black River, Bee Fork, and Ottery Creek. Five largely urban sub-basins were also considered; these basins are: Grand Glaize Creek, Glaize Creek, Sugar Creek, Hominy Creek, and Grindstone Creek. For each watershed, both water quality parameters and benthic macroinvertebrates ...


Program Management For Concurrent University Satellite Programs, Including Propellant Feed System Design Elements, Shannah Withrow-Maser Jan 2019

Program Management For Concurrent University Satellite Programs, Including Propellant Feed System Design Elements, Shannah Withrow-Maser

Masters Theses

"Propulsion options for CubeSats are limited but are necessary for the CubeSat industry to continue future growth. Challenges to CubeSat propulsion include volume/mass constraints, availability of sufficiently small and certified hardware, secondary payload status, and power requirements. A multi-mode (chemical and electric) thruster was developed by at the Missouri University of Science and Technology to enable CubeSat propulsion missions. Two satellite buses, a 3U and 6U, are under development to demonstrate the multi-mode thruster's capabilities. Two key challenges related to these missions are the development of the feed system to support the thruster and management of the two ...


Gel Composition And Brine Concentration Effect On Hydrogel Dehydration Subjected To Uniaxial Compression, Xinrui Zhao Jan 2019

Gel Composition And Brine Concentration Effect On Hydrogel Dehydration Subjected To Uniaxial Compression, Xinrui Zhao

Masters Theses

"Gel treatment is a process that injects the gel into a reservoir to control the conformance and improve the sweep efficiency of injection fluids. At a certain pressure gradient, the gel dehydrates in a reservoir due to mechanical forces. This work evaluates the effects of the gel composition and brine concentration on gel dehydration under uniaxial compression. A sodium acrylate-co-acrylamide based gel cross-linked with N, N'-Methylenebisacrylamide (MBAA) was used for the study. The compression test is performed with a rheometer with a plate-plate geometry. The gel dehydration under pressure was measured to see how gel dehydration would be impacted ...


Coupling Path Visualization Based On Reciprocity Theorem, Yang Zhong Jan 2019

Coupling Path Visualization Based On Reciprocity Theorem, Yang Zhong

Masters Theses

"A new method to visualize coupling path is proposed to help solve EMI problems. Based on the reciprocity theorem and the concept of reaction, coupling coefficient (CC) is defined to characterize coupling power density. For two-port networks, surface integral of CC can represent coupled voltage on the open-circuited port or coupled power on the loaded port. For dipole-moment based systems, surface integral of CC can represent coupled field components. The calculated CC should be a complex scalar at each point. By properly adjusting the excitation phases, the imaginary part of surface integral of CC will be zero and thus can ...


Breaker Evaluation And Formation Damage Remediation Of Re-Crosslinkable Preformed Particle Gel (Rppg), Enze Zhou Jan 2019

Breaker Evaluation And Formation Damage Remediation Of Re-Crosslinkable Preformed Particle Gel (Rppg), Enze Zhou

Masters Theses

"Re-crosslinkable preformed particle gel (RPPG) is a newly developed preformed particle gel for improving sweep efficiency and oil recovery by blocking or reducing the conductivity of fractures and fracture-like channels or conduits. However, RPPG has the potential to plug the facilities or damage the formation if a treatment is not properly conducted.

This work presents the performance of selected oxidizing breakers on the degradation of RPPG. The influence of a few factors on the degradation process was investigated, including breaker type, breaker concentration, temperature, gel concentration, gel aging time, and gel size. Results indicate that breaker type, concentration, and temperature ...


Using The Ert Method To Differentiate Resistivity Anomalies Attributed To Natural And Man-Made Activities, Ibrahim Faisal Alshareef Jan 2019

Using The Ert Method To Differentiate Resistivity Anomalies Attributed To Natural And Man-Made Activities, Ibrahim Faisal Alshareef

Masters Theses

"Karst terrain is considered to be a very complex topography compared with most other geological environments. Many features can be observed such as sinkholes, air-filled cavities, losing streams, and solution widened joints. These karst features can cause subsidence and damage infrastructure such as buildings and roads thus causing economic hardship and disruption of life. The typical geological and hydrological studies are not enough to understand the karst processes.

For this reason, two geophysical methods were involved in investigating the subsurface in the study area. In this research, the electrical resistivity tomography (ERT) and multichannel analysis of surface wave (MASW) data ...


Passively-Coded Embedded Microwave Sensors For Materials Characterization And Structural Health Monitoring (Shm), Katelyn Rose Brinker Jan 2019

Passively-Coded Embedded Microwave Sensors For Materials Characterization And Structural Health Monitoring (Shm), Katelyn Rose Brinker

Masters Theses

"Monitoring and maintaining civil, space, and aerospace infrastructure is an ongoing critical problem facing our nation. As new complex materials and structures, such as multilayer composites and inflatable habitats, become ubiquitous, performing inspection of their structural integrity becomes even more challenging. Thus, novel nondestructive testing (NDT) methods are needed. Chipless RFID is a relatively new technology that has the potential to address these needs. Chipless RFID tags have the advantage of being wireless and passive, meaning that they do not require a power source or an electronic chip. They can also be used in a variety of sensing applications including ...


Development Of Test Methods For Characterizing Extrudability Of Cement-Based Materials For Use In 3d Printing, Jonathan Thomas Kuchem Jan 2019

Development Of Test Methods For Characterizing Extrudability Of Cement-Based Materials For Use In 3d Printing, Jonathan Thomas Kuchem

Masters Theses

"3D printing is the process of creating three-dimensional objects using an automated additive manufacturing process. The 3D printing process has been used with materials such as metals and polymers, but application with cement based materials for the construction industry has yet to be developed. In this research, two main problems were investigated for printing cement based composite materials: extrudability and tensile reinforcement. Fiber-reinforced concrete (FRC) was studied as an internal reinforcing system to increase tensile/flexural strength. First, FRC was studied to investigate mechanical properties and use of fibers from waste tires as an environmentally friendly option. A reference mixture ...


Transient Multiphase Flow Simulation For Unloading Of Frac Hit Gas Wells, Miguel Angel Cedeno Moreno Jan 2019

Transient Multiphase Flow Simulation For Unloading Of Frac Hit Gas Wells, Miguel Angel Cedeno Moreno

Doctoral Dissertations

"This work seeks to develop a fully step-by-step transient multiphase flow simulation valid for unloading gas wells using nitrogen. It studies the behavior of nitrogen for unloading horizontal gas wells with gas injection in the annulus. The work investigates unloading non-Newtonian fluids such as those which invade offset wells when a frac hit occurs during hydraulic fracturing operations in unconventional wells. The effect of varying tubing depth and injection pressure are included in the study.

Results show that as the plastic viscosity increases, the nitrogen volume and time to unload will be increased. As tubing depth increases, the nitrogen volume ...


Detection And Elimination Of Rock Face Vegetation From Terrestrial Lidar Data Using The Virtual Articulating Conical Probe Algorithm, Kenneth John Boyko Jan 2019

Detection And Elimination Of Rock Face Vegetation From Terrestrial Lidar Data Using The Virtual Articulating Conical Probe Algorithm, Kenneth John Boyko

Doctoral Dissertations

"A common use of terrestrial lidar is to conduct studies involving change detection of natural or engineered surfaces. Change detection involves many technical steps beyond the initial data acquisition: data structuring, registration, and elimination of data artifacts such as parallax errors, near-field obstructions, and vegetation. Of these, vegetation detection and elimination with terrestrial lidar scanning (TLS) presents a completely different set of issues when compared to vegetation elimination from aerial lidar scanning (ALS). With ALS, the ground footprint of the lidar laser beam is very large, and the data acquisition hardware supports multi-return waveforms. Also, the underlying surface topography is ...


Ferrite Characterization Techniques & Particle Simulations For Semiconductor Devices, Nicholas Erickson Jan 2019

Ferrite Characterization Techniques & Particle Simulations For Semiconductor Devices, Nicholas Erickson

Doctoral Dissertations

"This dissertation is divided into three papers, covering two major topics. The first topic, techniques for ferrite characterization, is discussed over the course of two papers. The second topic, particle simulations for semiconductor devices, is discussed in the last paper. In the first paper, the method for extracting permeability from ferrite materials is discussed for the Keysight 16454A permeability extraction fixture, where the ferrite material to be characterized is assumed to be homogeneous. Then the method is updated to account for layered materials. The updated method is verified through full-wave simulations. In the second paper, a planar printed circuit board ...


Chemically-Bonded Enamel-Coated Steel Pipelines For Corrosion Protection And Flow Efficiency, Liang Fan Jan 2019

Chemically-Bonded Enamel-Coated Steel Pipelines For Corrosion Protection And Flow Efficiency, Liang Fan

Doctoral Dissertations

"This study is to explore and develop chemically-bonded enamel coating (200-300 um) on steel pipes, when subjected to soil and thermal environments, in order to improve the corrosion protection and safety of hazardous liquid and natural gas pipelines while reducing pressure loss. Out of five types of enamels and their various mixtures, Tomatec slurry and GP2118 powder were selected for steel pipeline applications. They were applied at approximately 810 °C to the inside surface of steel pipes in wet and electrostatic processes, respectively. The thickness and surface roughness of the enamel coating were measured using a gauge and an optical ...


The Tabu Ant Colony Optimizer And Its Application In An Energy Market, David Donald Haynes Jan 2019

The Tabu Ant Colony Optimizer And Its Application In An Energy Market, David Donald Haynes

Doctoral Dissertations

"A new ant colony optimizer, the 'tabu ant colony optimizer' (TabuACO) is introduced, tested, and applied to a contemporary problem. The TabuACO uses both attractive and repulsive pheromones to speed convergence to a solution. The dual pheromone TabuACO is benchmarked against several other solvers using the traveling salesman problem (TSP), the quadratic assignment problem (QAP), and the Steiner tree problem. In tree-shaped puzzles, the dual pheromone TabuACO was able to demonstrate a significant improvement in performance over a conventional ACO. As the amount of connectedness in the network increased, the dual pheromone TabuACO offered less improvement in performance over the ...


Hardware Architectures For Compact Microwave And Millimeter Wave Cameras, Matthew Jared Horst Jan 2019

Hardware Architectures For Compact Microwave And Millimeter Wave Cameras, Matthew Jared Horst

Doctoral Dissertations

"Millimeter wave SAR imaging has shown promise as an inspection tool for human skin for characterizing burns and skin cancers. However, the current state-of-the-art in microwave camera technology is not yet suited for developing a millimeter wave camera for human skin inspection. Consequently, the objective of this dissertation has been to build the necessary foundation of research to achieve such a millimeter wave camera. First, frequency uncertainty in signals generated by a practical microwave source, which is prone to drift in output frequency, was studied to determine its effect on SAR-generated images. A direct relationship was found between the level ...


Time-Dependent Reliability Methodologies With Saddlepoint Approximation, Zhangli Hu Jan 2019

Time-Dependent Reliability Methodologies With Saddlepoint Approximation, Zhangli Hu

Doctoral Dissertations

"Engineers always encounter time-dependent uncertainties that ubiquitously exist, such as the random deterioration of material properties and time-variant loads. Therefore the reliability of engineering systems becomes time-dependent. It is crucial to predict the time-dependent reliability in the design stage, given possible catastrophic consequences of a failure. Although extensive research has been conducted on reliability analysis, estimating the reliability accurately and efficiently is still challenging. The objective of this work is to develop accurate and efficient reliability methodologies for engineering design. The basic idea is the integration of traditional reliability methods with saddlepoint approximation (SPA), which can accurately approximate the tail ...


Reliability Analysis For Systems With Outsourced Components, Zhengwei Hu Jan 2019

Reliability Analysis For Systems With Outsourced Components, Zhengwei Hu

Doctoral Dissertations

"The current business model for many industrial firms is to function as system integrators, depending on numerous outsourced components from outside component suppliers. This practice has resulted in tremendous cost savings; it makes system reliability analysis, however, more challenging due to the limited component information available to system designers. The component information is often proprietary to component suppliers. Motivated by the need of system reliability prediction with outsourced components, this work aims to explore feasible ways to accurately predict the system reliability during the system design stage. Four methods are proposed. The first method reconstructs component reliability functions using limited ...


Atomistic Simulations Of Deformation In Metallic Nanolayered Composites, Sixie Huang Jan 2019

Atomistic Simulations Of Deformation In Metallic Nanolayered Composites, Sixie Huang

Doctoral Dissertations

"The mechanical behavior of Metallic Nanolayered Composites (MNCs) is governed by their underlying microstructure. In this dissertation, the roles of the interlayer spacing (grain size, d) and the intralayer biphase spacing (layer thickness, h) on mechanical response of Cu/Nb MNCs are examined by Molecular Dynamics (MD) simulations. The study of the strength of MNCs show that small changes in both d and h play a profound role in the relative plastic contributions from grain boundary sliding and dislocation glide. The interplay of d and h leads to a very broad transition region from grain boundary sliding dominated flow, where ...


Assessment And Prediction Of Surface Water Vulnerability From Non-Point Source Pollution In Midwestern Watersheds, Fadhil K. Jabbar Jan 2019

Assessment And Prediction Of Surface Water Vulnerability From Non-Point Source Pollution In Midwestern Watersheds, Fadhil K. Jabbar

Doctoral Dissertations

"Non-point source pollution is the leading cause of impairment in surface water in the Midwest. In this research, we seek to predict which watersheds are most vulnerable to point source pollution without field sampling using publically available GIS databases. Watersheds with higher vulnerability ratings can then be targeted for water quality monitoring, and funds used to improve watershed health can be distributed with greater efficacy. To better understand and target watershed vulnerability, we used three different approaches. In the first project, 35 sub-watersheds were sampled in the Lower Grand Watershed, which is a highly agricultural watershed in northern Missouri/southern ...


Epitaxial Growth Of Semiconductors And Chiral Metal Surfaces Using Spin Coating And Electrodeposition, Meagan V. Kelso Jan 2019

Epitaxial Growth Of Semiconductors And Chiral Metal Surfaces Using Spin Coating And Electrodeposition, Meagan V. Kelso

Doctoral Dissertations

"The current primary methods for epitaxial growth are energy intensive, requiring high temperature or high vacuum to obtain quality thin films. This dissertation explores the solution process methods of electrodeposition and spin coating for growth of epitaxial thin films. First, a method is developed to directly electrodeposit epitaxial CH3NH3PbI3 perovskite for solar cells on single crystal Au by electrochemically reducing I2 in organic solution. Perovskite is a newly explored material for solar cells, and its efficiency may be further improved by increasing the crystalline order. Second, a study on epitaxially electrodeposited chiral metal surfaces ...