Digital Commons Network^™

Analysis Of Electromagnetic Interference Problems Causedbyhigh-Speed Multiplayer Boards With Split Referenceplane, Xin Fang

Masters Theses

"Digital/Analog ground partitioning has been used to isolate noisy digital and power current from sensitive analog currents in high-speed multiplayer printed circuit boards. The through-hole signal via enables convenient routing and component placement on the PCB and is used for signal interconnections when the signal traces are changing the layers. This design, however, breaks the current return path for signal traces that cross the two separated grounds, which causes undesired effects such as signal distortion and radiated emission.

Electromagnetic mechanism associated with them needs to be understood to control and suppress these undesired effects. In this paper, we have investigated …

Integrating Remote Sensing And Model-Based Datasets In A Machine Learning Model To Map Global Subsidence Associated With Groundwater Withdrawal, Md Fahim Hasan

Masters Theses

"Quantifying groundwater storage loss is becoming increasingly essential globally due limited availability of this major hydrologic component and its long recharge time. Groundwater overdraft gives rises to multiple adverse impacts including land subsidence and permanent groundwater storage loss. In absence of spatially dense monitoring network, publicly available in-situ data, and uniform monitoring strategies, it is challenging to assess the sustained losses from overexploitation of this resource. Remote sensing based techniques have the capacity to fill this gap to increase our groundwater monitoring capacities. Exploring the interrelation between groundwater pumping and land subsidence using remote sensing datasets can be a very …

Assessing Phenotypic Response Of Plants Irrigated With Municipal Solid Waste Landfill Leachate Using Computer Visualization, Rahel Pommerenke

Masters Theses

"Most solid waste collected in the US is disposed of in sanitary landfills, which have a lingering legacy of unintended negative impacts on the environment. Landfill design and operation are expensive, prone to multiple failure modes, and often do not address human and ecological risks presented by contaminants of emerging concern. A notable and common failure mechanism is leachate production. Moisture in the waste mixes with infiltrating water to form wastewater that must be collected and treated prior to discharge. Recycling leachate at landfills by recirculating it onto vegetated landfill covers relies on the evapotranspiration potential of plants to reduce …

Smart Living With Artificial Intelligence -- Potential Impact Of Artificial Intelligence On Mental Well-Being, Weiyu Wang

Masters Theses

"Artificial Intelligence (AI) will result in job replacement and job elimination. Some AI technologies, such as self-driving vehicles, have the potential to disrupt existing industries. Self-driving trucks may replace the 3.5 million truck drivers in the US. Scholars at Oxford University estimated that no less than 47% of American jobs and 54% of those in Europe are at a high risk of being taken over by machines. Routine, repetitive, and predictable jobs are expected to be automated (Siau, 2018). Although new jobs will be created, the unemployment rate may go up in the short term and the emergence of a …

Ecological Restoration Of Lead/Zinc/Copper Mine Tailings: Phytomanagement And Amendment Strategies To Enhance Substrate Functionality And Biomass Production, Mariam K. Al-Lami

Doctoral Dissertations

“The extreme physiochemical characteristics of mine tailings inhibit microbial processes and natural plant growth. Consequently, vast and numerous tailings sites remain barren for decades and highly susceptible to wind and water erosion. Phytostabilization is a cost-effective and ecologically productive remediation approach; however, tailings revegetation is generally challenging and must often be assisted with appropriate soil amendments. Amendments applied individually in greenhouse studies discussed herein revealed notable improvement in bioenergy crops growth only with biosolids treatments. Recalcitrant carbon amendments (biochar and humus) showed notable impact only on tailings physichochemical and hydraulic properties. Nevertheless, biosolids may not support sustained vegetation due to …

Theoretical And Experimental Application Of Neural Networks In Spaceflight Control Systems, Pavel Galchenko

Doctoral Dissertations

“Spaceflight systems can enable advanced mission concepts that can help expand our understanding of the universe. To achieve the objectives of these missions, spaceflight systems typically leverage guidance and control systems to maintain some desired path and/or orientation of their scientific instrumentation. A deep understanding of the natural dynamics of the environment in which these spaceflight systems operate is required to design control systems capable of achieving the desired scientific objectives. However, mitigating strategies are critically important when these dynamics are unknown or poorly understood and/or modelled. This research introduces two neural network methodologies to control the translation and rotation …

Characterization And Utilization Of Alkali-Activated Concrete For Sustainable Infrastructures, Eslam Gomaa

Doctoral Dissertations

“This study has investigated the feasibility of using locally available fly ashes (FAs) to synthesize alkali-activated concrete (AAC) for different structural and repair applications. Using AAC made of 100% FA reduces global CO2 emissions, saves energy, and decreases raw material consumption during the production process of ordinary Portland cement. Class C FAs, sourced from Labadie, Jeffery City, Kansas City, Thomas Hill, and Sikeston power plants in the state of Missouri, were used to synthesize the AAC. Sodium silicate (SS), Na2SiO3, and sodium hydroxide (SH), NaOH were used as the alkali activators. Slag, crumb rubber, and air-entraining admixture were used as …

Scale Formation, Properties And De-Scaling In Steelmaking, Richard Osei

Doctoral Dissertations

During continuous castings, reheating, and hot rolling, slab surfaces are exposed to atmospheres containing oxidizing gases which results in scale formation. Inefficient removal of the formed scale during reheating affects product surface quality. The effect of steel composition and operating parameters on scale formation and scale removal efficiencies were investigated. Experimental investigations were carried out using a thermogravimetric (TGA) apparatus designed to replicate the combustion gas atmosphere and temperature in actual industrial slab reheat furnaces. Report on oxidation kinetics, scale structure and properties, and descaling were conducted on laboratory cast and industrial samples. Different characterization techniques were used to analyze …

The Utilization And Loss Of Available Energy In Aerospace Systems, Mohammad Abbas

Doctoral Dissertations

“Theoretical principles and analytical methodology for the control volume-based energy availability methodology for aerospace vehicles are developed; applications are made to jet-propelled and rocket-propelled vehicles as well as to stand-alone engine systems. Energy availability utilization characteristics of a modeled turbojet engine are studied across a wide range of operating conditions of throttle setting, flight altitude, and flight Mach number. The method is also extended to consider jet-powered vehicles. Fundamental principles regarding entropy generation and energy availability are developed, including directly linking entropy generation and maximum range and endurance of a powered aircraft. Theory and application of the energy utilization methodology …

Synthesis, Characterization And Chemistry Of Two-Dimensional Transition Metal Carbides And Nitrides (Mxenes), Shuohan Huang

Doctoral Dissertations

"MXenes represent a relatively new and quickly growing family of two-dimensional (2D) early transition-metal carbides and nitrides first synthesized in 2011 from bulk layered crystalline MAX phases. Because of their 2D structure and unique combination of high conductivity and hydrophilicity, MXenes have raised a significant interest for various applications. However, it has been found that in some cases colloidal MXene flakes are not stable and can spontaneously degrade on a time scale from hours to days. In this work, we investigate the crucial factors for MXene degradation and demonstrate gas analysis as a powerful method to gain further insights into …

Distributed Fiber-Optic Temperature Sensors For Applications In The Steel Industry, Muhammad Roman

Doctoral Dissertations

"Steelmaking facilities require continuous temperature measurements throughout the manufacturing process to ensure consistent product quality and high productivity. Motivated by the limitations of conventional temperature sensors, distributed fiber-optic sensors (DFOS) were developed and deployed for various applications in the steel industry. Fiber-optic sensors offer various advantages over conventional sensors, such as the miniaturized size of the optical fiber, immunity to electromagnetic interferences, capability for multiplexing and distributed sensing, and the ability to withstand harsh environments.

Firstly, high-resolution Rayleigh backscattering based DFOS were demonstrated as potential solutions for temperature measurements in steelmaking processes by performing experimental simulations. Additionally, aluminum casting experiments …

A Three-Dimensional Fully Coupled Hydro-Mechanical Elasto-Plastic Model For Unsaturated Soils With Consideration Of Hysteresis Behavior, Beshoy Sami Moussa Riad

Doctoral Dissertations

"Unsaturated soils are often used as a construction material in transportation infrastructures; in which it is subjected to cyclic traffic loadings and/or seasonal wetting-drying cycles. While mechanical hysteresis is a common feature of soils in general, hydraulic hysteresis is associated with unsaturated soils. Most existing constitutive models paid limited attention to the mechanical and hydraulic hysteresis behavior of unsaturated soils. This research presents a three-dimensional model for unsaturated soils and a chemo mechanical model for saturated soils. The unsaturated soils’ model has the following characteristic features: (a) the hydraulic and mechanical behaviors are fully coupled under 3D conditions; (b) it …

Strategies To Improve Shrinkage Resistance Of Cement-Based Materials For Extrusion-Based 3d Printing, Kavya Vallurupalli

Doctoral Dissertations

"The main objective of this study is to develop new generation of shrinkage-resistant 3D printable mortar mixtures. To this end, the research work was carried out to: i) identify key material and processing parameters that affect printability; ii) investigate the influence of water-to-cement ratio, superplasticizer dosage, and welan gum content on mortar printability; iii) propose a “printability window” where rheological properties and desorptivity can secure successful printing; iv) investigate effect of shrinkage mitigation materials (expansive agent (EA), pre-saturated lightweight sand (LWS), superabsorbent polymers (SAP), and shrinkage reducing admixture) on printability and shrinkage performance of mortar; and v) evaluate the effect …

Establishing Pteridine Metabolism In A Breast Cancer Cell Model And Quantification Of Silver Nanoparticle Interactions With Yeast Cells Using Mass Spectrometry, Lindsey Katherine Rasmussen

Doctoral Dissertations

"Recent advances in analytical methods have furthered the quantitative insights that can be gleaned from cellular analyses, with applications in cancer and nanoparticle research. In the first part of the research presented, a recently developed HPLC-MS/MS method was advanced to elucidate pteridine metabolism in an isogenic progressive MCF10A breast cancer cell model. The folate-derived pteridine pathway in breast cells was established by individually dosing cell cultures with folic acid and 15 pteridines. Eight potential pteridine biomarkers in breast cancer cells were identified including pterin and isoxanthopterin, which yielded the first in vitro evidence for the cellular metabolisms behind previously reported …

Processing To Enable Direct-Write Additive Manufacturing Of Ceramics And Ceramic Composites, Austin Martin

Doctoral Dissertations

"This research focuses on the processing of novel feedstocks for and during direct-write additive manufacturing (AM), specifically the direct ink writing (DIW) and Ceramic On-Demand Extrusion (CODE) manufacturing processes, in order to produce ceramic and ceramic-based composite components. Strongly dispersed, concentrated (φ = 0.42), nanoparticle (d₅₀ ~0.3 µm), zirconia (ZrO₂) pastes were used to print densely filled, large continuous volume (≳ 1 cm³) ceramic components. An elastic shear modulus (G’) of 56,000 Pa and yield stresses between 6 and 10 Pa allowed for printed components of 34.5 mm in height over 115 layers without slumping …

Secure And Efficient Information Management In Delay(Disruption) Tolerant Network, Shudip Datta

Doctoral Dissertations

"In environments like international military coalitions on the battlefield or multi-party relief work in a disaster zone, multiple teams are deployed to serve different mission goals by the command-and-control center (CC). They may need to survey damages and send information to the CC for situational awareness and also transfer messages to each other for mission purposes. However, due to the damaged network infrastructure in the emergency, nodes need to relay messages using the store and forward paradigm, also called Delay-tolerant Networks (DTNs). In DTN, the limited bandwidth, energy, and contacts among the nodes, and their interdependency impose several challenges such …

Design And Performance Of Self-Consolidating And Thixotropic Ultra-High-Performance Concrete For Infrastructure Construction And Rehabilitation, Le Teng

Doctoral Dissertations

"The objective of this research is to develop two classes of ultra-high-performance concrete (UHPC), one with self-consolidating consistency and the other with improved thixotropy. Tailoring the rheological properties of low yield stress UHPC can improve dispersion and orientation of steel fibers used in the design of UHPC, hence enhancing the tensile and flexural properties. Similarly, improving the thixotropy of UHPC can enable unique performance for the design of thin bonded bridge deck overlay. The research investigated various thixotropy enhancing admixtures to enhance the structural build-up at rest of UHPC. A total of 16 bonded overlay slab specimens were used to …

Determining Thermal Properties Via Parameter Estimation Of A One-Dimensional, Analytical Model, Lauren B. Tomanek

Doctoral Dissertations

“In thermal applications, thermal conductivity is used to predict how well a material conducts heat. The accuracy of the magnitude of the thermal conductivity becomes increasingly essential to optimize part geometry. Thermal conductivity can vary significantly from the nominal value due to post-processing. The ASTM standards available to measure thermal conductivity are challenging to reproduce because of the insulated and prescribed temperature boundary conditions that are needed. The research introduces two new methods for estimating thermal conductivity that deliver the same accuracy as the existing ASTM standards and are easier to implement. The methods account for losses in the heating …

Engineering Ni/Al2o3 Catalysts By Atomic Layer Deposition For Methane Reforming, Baitang Jin

Doctoral Dissertations

"Dry reforming of methane (DRM) could be a promising choice to utilize natural gas (mainly methane or CH₄), recycle captured CO₂, and produce valuable syngas. Promoters (e.g., CeO₂ and MgO) on Ni/Al₂O₃ prepared by atomic layer deposition (ALD) and ALD-prepared ultrathin overcoating (e.g., ZrO₂ and CeO_x) on Ni/Al₂O₃ prepared by incipient wetness method were investigated for methane reforming.

MgO and CeO₂ prepared by traditional incipient wetness method were used to promote the performance of ALD-prepared Ni nanoparticles (NPs) supported on four-channel α-Al₂O_{3 …}

Investigating The Interaction Between The Recycled Components And The Asphalt Binders, Plant, Lab, And Field Mixes, Eslam Deef-Allah

Doctoral Dissertations

"Modifying asphalt binders and mixes with recycled components is common practice due to their environmental and economic merits. Literature has indicated that different recycled components interact with (blend with) asphalt differently, ranging from no blending, partial blending, or full blending. The degree of blending between recycled components and virgin asphalt binders (VABs) and the exchanged components impact the performance of modified asphalt binders. However, the nature of the interaction process between the recycled components and the VABs is not fully understood. The primary objective of this study was to explore the interactions between recycled components and VABs. By understanding the …

Evaluation Of Novel Preformed Particle Gels For Conformance Control And Acid Stimulation Through Core Flooding Tests, Shuda Zhao

Doctoral Dissertations

"Acid stimulation and conformance control are two major methods to improve oil production. This study systematically evaluates two newly developed gels: Degradable Preformed Particle Gel (DPPG) and Re-crosslinkable Preformed Polymer Gel (RPPG). DPPG is designed to be a temporary plugging agent for acid stimulation and can self-degrade into a water-like fluid. RPPG is designed for reservoir sweep efficiency improvement and can re-crosslink to each other and form an immobile bulk gel after being placed in fractures or fracture-like conduits.

For DPPG, this study evaluates the effect of monomer, crosslinker, and initiator concentration on the swelling and degradation performance. Results show …

Theoretical Determination Of The Yield Curve For Unsaturated Soils, Sara Fayek

Doctoral Dissertations

"An important step to developing a good understanding of the behavior of unsaturated soils is to adopt a formal and simple constitutive framework and to conduct high-quality and short-time experiments. Barcelona Basic Model (BBM) was the first elastoplastic constitutive model for unsaturated soils. The yield curve, which separates the elastic region from the elastoplastic region, is an important aspect of constitutive modeling for unsaturated soils. Most concepts for unsaturated soils were developed based upon the results from suction-controlled triaxial (SCTX) tests. Though, the SCTX tests on unsaturated soils are costly, time-consuming, and laborious, and their results are questionable. This study …

Promoting Distributed Energy Deployment And Diffusion For Sustainable Civil Infrastructure Using Multi-Agent Based Modeling And Quantitative Analytics, Gasser Ali

Doctoral Dissertations

"Distributed Solar Generation (DSG) using small-scale Photo-Voltaic (PV) is an evolving technology with increasingly growing market penetration due to its significant benefits to consumers and broader power systems. DSG is sustainable, provides reliability, and is cost-effective where solar energy is abundant. However, the increasingly growing adoption of DSG creates uncertainties in forecasting electric power demand and market behavior. It also causes concerns of a “utility death spiral”. To this end, the goal of this research is to critically analyze the diffusion and benefits of DSG in the electric power infrastructure as a complex System-of-Systems (SoS). Specifically, this dissertation addresses the …

Depositional Conditions, Stratigraphic Evolution, And Allo- And Autogenic Controls Of Lower Permian Non-Marine Carbonate Rocks, Lucaogou Low-Order Cycle, Bogda Mountains, Nw China, Yiran Lu

Doctoral Dissertations

"The overall objective of this study is to interpret the depositional conditions of lacustrine carbonate deposits of the lower Permian Lucaogou low-order cycle in the greater Turpan-Junggar continental rift basin, NW China. The depositional environments of ten carbonate lithofacies in the Tarlong-Taodonggou half graben and the Zhaobishan section were interpreted. Allo- and autogenic factors were identified. They controlled characteristics and distribution pattern of carbonate deposits in regional and local scale, respectively. Allogenic factors include the amount and direction of regional siliciclastic input, basin geometry, cyclic humidity/aridity oscillation, temperature, and regional tectonics. Autogenic factors include local siliciclastic input, local topography, local …

Adsorption Of Arsenic Onto River Sediments, Leticia Augusta Dos Santos Ferreira

Masters Theses

“Previous studies have noted the relationship between shallow groundwater rich in sodium (Na) and bicarbonate (HCO₃) and elevated levels of dissolved arsenic. However, most experimental work on arsenic adsorption in the presence of HCO₃ and differing Na/Ca ratios has proven difficult to extrapolate to natural systems because of differences in tested mineral compositions and component concentrations. In this study, I performed a series of adsorption experiments using river sediments to evaluate the influence of HCO₃ and monovalent/divalent cations on the extent of arsenic adsorption onto natural sediment in groundwater.

Batch adsorption (kinetics, equilibrium, and metal loading) …

Automatic Sparse Esm Scan Using Gaussian Process Regression, Jiangshuai Li

Masters Theses

“Emission source microscopy (ESM) technique can be utilized for localization of electromagnetic interference sources in complex and large systems. In this work a Gaussian process regression (GPR) method is applied in real-time to select sampling points for the sparse ESM imaging using a motorized scanner. The Gaussian process regression is used to estimate the complex amplitude of the scanned field and its uncertainty allowing to select the most relevant areas for scanning. Compared with the randomly selected samples the proposed method allows to reduce the number of samples needed to achieve a certain dynamic range of the image, reducing the …

Predicting Radiated Emissions From A Cable Harness Through Component Level Tests, Fuwei Ma

Masters Theses

“In this work, a procedure is developed to predict the radiated emissions from a cable harness using component-level tests. Direct measurement on the engine control unit is utilized to accurately characterize the equivalent common mode source voltages and impedance associated with the device. The cable harness geometry is reduced using the equivalent cable bundle approach by lumping wires according to the source and load impedance compared with characteristic impedance of the harness, which dramatically reduces the measurement effort and allows practical 3D full-wave simulation of the radiated emissions. Radiated emissions are predicted from an engine control unit (ECU) and an …

Zinc Plating From Alkaline Non-Cyanide Bath, Abdul J. Mohammed

Masters Theses

“Alkaline non-cyanide zinc plating baths are preferred when trying to avoid the toxicity of cyanide baths or corrosivity of acid baths. Without additives, alkaline zincate baths produce powdery non-adherent deposits which have no use in commercial plating. Additives must be added at optimum concentrations to produce adherent, bright and uniform zinc deposits. In this study electrochemical tests were used to determine effects of additives on cathodic polarization, throwing power and morphology of deposits. Current density distribution in a unique bath of 37.5 g L^-1 Zn and 210 g L^-1 NaOH was modelled using COMSOL and validated two plating …

Study Of Contamination Resulting From Historical Mining Within The Old Lead Belt: Mineral Fork Watershed, 2021-2022, Tessa Nicole Mortensen

Masters Theses

“The Old Lead Belt in Missouri has been mined extensively over the past two hundred years, and with historical mining practices often not meeting modern environmental protection standards many areas have significant soil and water contamination as a result. This study focuses on the Mineral Fork River’s watershed in Washington County, Missouri, which includes portions of four separate Superfund sites. In this study, we exam the impact of historical mining on the health of alluvial systems, as evaluated by lead, zinc, and barium (barite) concentrations in the suspended and sediments within tributaries of the Mineral Fork River system. To relate …

Industry 4.0 Remanufacturing: A Novel Approach Towards Smart Remanufacturing, Prashansa Ragampeta

Masters Theses

“Smart remanufacturing has become more popular in recent years as a result of its multiple benefits and the growing need for society to encourage a circular economy that leads to sustainability. One of the most common end-of-life (EoL) choices that can lead to a circular economy is remanufacturing. As a result, at the end-of-life stage of a product, it is critical to prioritize this choice over other accessible options because it is the only recovery option that retains the same quality as a new product. This work focuses on the numerous technologies that can aid in the improvement of smart …