Digital Commons Network^™

Mass Transfer Studies In Heavy Oil Recovery Using Solvents, Vijitha Mohan

Doctoral Dissertations

"Heavy oil, sometimes called bitumen, is known for its high viscosity (above 100 cp) and low API gravity (below 22⁰). In most cases, viscosity reduction is needed for the final product. There is a considerable amount of heavy oil in Alberta, Canada and the world's largest heavy oil deposit is in Venezuela. Yet less than 1% of it can be recovered because of its high viscosity. For shallow reservoirs, it is possible to resort to open cast mining. For deeper reservoirs, steam is used at ~ 350 ⁰C which gets the oil viscosity reduced to 1cp, which can now be …

The Use Of Geophysical Methods For Dam Seepage Investigations And Dredged Oyster Deposit Characterization, Stanley Chinedu Nwokebuihe

Doctoral Dissertations

"The dissertation is made up of three papers, which discuss the utility of geophysical tools in earthfill dam investigations and dredged oyster bed characterization.

In the first paper, an earthfill dam in Warren County, Missouri was effectively investigated for seepage through the dam and its outlet works using an integration of the electrical resistivity tomography, induced polarization and spontaneous potential geophysical tools. Recommendations were subsequently made based on the results of the study on grout locations to prevent further seepage. In the second paper, a similar study of earthfill dam seepage was conducted on a different dam in Southern Missouri. …

Rapid Quantification Of Trypsin Inhibitors In Food And Feed Formulations With Electrospray Ionization Mass Spectrometry, Radheshyam Panta

Doctoral Dissertations

"Presence of anti- nutrients deteriorate the nutritional value of animal foods and feed formulations. The important one being trypsin inhibitors. Trypsin inhibitors in food and feed formulations lower the protein supplement and hence the ultimate consequence is the decrease in growth and development of animals. It is therefore, crucial to monitor trypsin inhibitors in animal food and feed formulations. Research work mentioned in this dissertation is based on the development of rapid, more accurate and robust method for determination of trypsin inhibitor in food and feed formulations. The developed method includes extraction of trypsin inhibitor from food and feed formulation …

Environmental Hazard Identification, Assessment And Control For A Sustainable Maritime Transportation System, Lizzette Marie Pérez Lespier

Doctoral Dissertations

"A demand exists to contribute towards the widening awareness of the need for sustainable maritime development and for coordinated maritime policies worldwide. Maritime shipping is considered the most eco-efficient mean of transportation and yet, is responsible for negative environmental impacts.

This dissertation focuses on developing data-driven decision support tools to evaluate the sustainable performance of MTS by focusing on the elements of the MTS that place stress on the environment. The first research contribution is a System Dynamics simulation model that examines the MTS resiliency after an extreme event and determines the sequence needed to restore the ocean-going port to …

Dissolution-Enlarged Fractures Imaging Using Electrical Resistivity Tomography (Ert), Elnaz Siami-Irdemoosa

Doctoral Dissertations

"In recent years the electrical imaging techniques have been largely applied to geotechnical and environmental investigations. These techniques have proven to be the best geophysical methods for site investigations in karst terrain, particularly when the overburden soil is clay-dominated. Karst is terrain with a special landscape and distinctive hydrological system developed by dissolution of rocks, particularly carbonate rocks such as limestone and dolomite, made by enlarging fractures into underground conduits that can enlarge into caverns, and in some cases collapse to form sinkholes.

Bedding planes, joints, and faults are the principal structural guides for underground flow and dissolution in almost …

Layered Crustal And Mantle Structure And Anisotropy Beneath The Afar Depression And Malawi Rift Zone, Cory Alexander Reed

Doctoral Dissertations

"Although a wealth of geophysical data sets have been acquired within the vicinity of continental rift zones, the mechanisms responsible for the breakup of stable continental lithosphere are ambiguous. Eastern Africa is host to the largest contemporary rift zone on Earth, and is thus the most prominent site with which to investigate the processes which govern the rupture of continental lithosphere. The studies herein represent teleseismic analyses of the velocity and thermomechanical structure of the crust and mantle beneath the Afar Depression and Malawi Rift Zone (MRZ) of the East African Rift System. Within the Afar Depression, the first densely-spaced …

Remote Sensing And Localization Of Smart Rocks With Orientation-Controlled Magnets For Real-Time Monitoring Of Bridge Scour And Riprap Effectiveness, Yan Tang

Doctoral Dissertations

"This study aims to develop and implement a novel smart rock technology for real-time monitoring of the maximum scour depth and the effectiveness of riprap mitigation measures. A smart rock is one or more stacked magnets encased in concrete that can automatically roll to the deepest point of a scour hole around a bridge pier and provide its location through remote measurement over time. Once integrated into a riprap measure, the smart rock moves together with natural rocks and is thus a potential indicator of the effectiveness of the riprap measure. Therefore, the localization and movement of smart rocks were …

Smart Rocks For Bridge Scour Monitoring -- Design And Localization Using Electromagnetic Techniques And Embedded Orientation Sensors, Andro Radchenko

Doctoral Dissertations

"River bridge scour is an erosion process in which flowing water removes sediment materials (such as sand, rocks) from a bridge foundation, river beds and banks. As a result, the level of the river bed near a bridge pier is lowering such that the bridge foundation stability can be compromised, and the bridge can collapse. The scour is a dynamic process, which can accelerate rapidly during a flood event. Thus, regular monitoring of the scour progress is necessary to be performed at most river bridges. Present techniques are usually expensive, require large man/hour efforts, and often lack the real-time monitoring …

Novel Applications Of Pulse Pre-Pump Brillouin Optical Time Domain Analysis For Behavior Evaluation Of Structures Under Thermal And Mechanical Loading, Yi Bao

Doctoral Dissertations

"This study aims to: (1) develop an analytical model for the strain transfer effect of distributed fiber optic sensors in a uniform or non-uniform stress field; (2) develop a measurement approach to monitor strains in concrete and detect damage (e.g. crack and delamination) in bonded and unbonded concrete overlays; (3) characterize the strain and temperature sensitivities of distributed fiber optic sensors at elevated temperatures; (4) develop a thermal annealing approach to enhance the thermal stability and temperature sensitivity of the distributed sensors; and (5) apply the distributed sensors to assess structural behaviors of concrete and steel structures exposed to fire. …

Characterization And Performance Of Eco And Crack-Free High-Performance Concrete For Sustainable Infrastructure, Iman Mehdipour

Doctoral Dissertations

"The main objective of this study is to develop, characterize, and validate the performance of a new class of environmentally friendly, economical, and crack-free high-performance concrete referred to as Eco and crack-free HPC that is proportioned with high content of recycle materials. Two classes of Eco-HPC are designed for: (I) pavement (Eco-Pave-Crete); and (II) bridge infrastructure (Eco-Bridge-Crete). Eco-HPC mixtures were designed to have relatively low binder content up to 350 kg/m³ and develop high resistance to shrinkage and superior durability. A stepwise mixture design methodology was proposed to: (i) optimize binder system and aggregate skeleton to optimize packing density …

Contributing Factors To Child Stunting In Guatemala: A Systems Analysis Focused On Enteric Disease Transmission And Mycotoxin Exposure, Lee Emerson Voth-Gaeddert

Doctoral Dissertations

"Child stunting -- low height-for-age -- is a United Nation's indicator for chronic malnutrition that has been linked to both acute and chronic health problems. Data from Guatemala suggests for children under five years of age, 49% are classified as stunted. This dissertation tests the following hypotheses, among children in Guatemala 1) environmental enteric dysfunction (EED) is correlated with height-for-age, 2) aflatoxin B (AFB) exposure is correlated with height-for-age, and 3) AFB exposure is correlated with EED. A network analysis was conducted on data from the US Agency for International Development (USAID) collected in 2012 to identify trends in a …

High-Volume Recycled Materials For Sustainable Transportation Infrastructure, Seyedhamed Sadati

Doctoral Dissertations

"The objective of this study is to investigate the feasibility of using high performance concrete made with high-volume of recycled materials in transportation infrastructure. The main focus was to develop mixtures for rigid pavement construction. A variety of fine and coarse recycled concrete aggregates (RCA) were investigated. The feasibility of replacing 50% of Portland cement with industrial by-products and supplementary cementitious materials (SCMs) was also evaluated. Experimental program was conducted to quantify the effect of concrete mixture design and RCA characteristics on mechanical properties, drying shrinkage, cracking potential, and durability of concrete. The development of a database and analysis using …

Design And Performance Of Cost-Effective Ultra-High Performance Concrete For Prefabricated Elements, Weina Meng

Doctoral Dissertations

"This study presented in this thesis aims to: (1) develop a mixture design methodology for cost-effective ultra-high-performance concrete (UHPC) incorporating high volume of supplementary cementitious materials and conventional concrete and masonry sands; (2) developed UHPC with adapted rheology incorporating lightweight sand, hybrid fibers, and nanomaterials with improved properties; (3) design prefabricated UHPC panels with fiber-reinforced polymers (FRP) for enhanced flexural properties of stay-in-place panels made with optimized UHPC; and (4) explore potential applications of such UHPC elements. The proposed design methodology produced UHPC mixtures with 28-days compressive strengths higher than 125 and 168 MPa under standard water curing and 1-d …

Optimal Electric Vehicle Scheduling : A Co-Optimized System And Customer Perspective, Maigha

Doctoral Dissertations

"Electric vehicles provide a two pronged solution to the problems faced by the electricity and transportation sectors. They provide a green, highly efficient alternative to the internal combustion engine vehicles, thus reducing our dependence on fossil fuels. Secondly, they bear the potential of supporting the grid as energy storage devices while incentivizing the customers through their participation in energy markets. Despite these advantages, widespread adoption of electric vehicles faces socio-technical and economic bottleneck. This dissertation seeks to provide solutions that balance system and customer objectives under present technological capabilities. The research uses electric vehicles as controllable loads and resources. The …

Randomized Encoding Of Combinational And Sequential Logic For Resistance To Hardware Trojans, Travis Edward Schulze

Doctoral Dissertations

"Globalization of micro-chip fabrication has opened a new avenue of cyber-crime. It is now possible to insert hardware Trojans directly into a chip during the manufacturing process. These hardware Trojans are capable of destroying a chip, reducing performance or even capturing sensitive data. To date, defensive methods have focused on detection of the Trojan circuitry or prevention through design for security methods.

This dissertation presents a shift away from prevention and detection to a design methodology wherein one no longer cares if a Trojan is present or not. The Randomized Encoding of Combinational Logic for Resistance to Data Leakage or …

Durability Behavior Of Fiber Reinforced Polymer And Steel Reinforced Polymer For Infrastructure Applications, Wei Wang

Doctoral Dissertations

"Crack development in reinforced concrete (RC) structures is common in elements such as bridge decks. However, these cracks can impose significant problems over time, because they allow chlorides from deicing chemicals to infiltrate concrete which will then corrode steel bars as RC structures are exposed to harsh weather. In the last decade, composite reinforcement systems are internally or externally applied to concrete structures instead of traditional steel reinforcing bars, or to strengthen concrete elements in flexure and shear. However, studies regarding the long-term durability performance of composite reinforcement systems is limited. Therefore, in order to popularize the application of these …

Understanding The Deformation Mechanisms In Nanostructured Metals By A Novel Discrete Crystal Plasticity Finite Element Model, Rui Yuan

Doctoral Dissertations

"Implementation of nanostructured metals and alloys for use in engineering applications requires a detailed knowledge of the underlying deformation mechanisms in these materials. It is well known that plastic deformation in metals and alloys is mainly mediated by dislocation activities. Nonetheless, TEM observations and atomistic simulations indicate that dislocation-mediated plasticity in nanostructured metals and alloys is significantly different from that in their coarse-grained counterparts. Therefore, this dissertation focuses on the exploration of the deformation mechanisms in nanostructured metals via crystal plasticity finite element modeling and simulation.

A statistical grain boundary dislocation source model accounting for dislocation nucleation and slip events …

Bootstrap-Based Confidence Intervals In Partially Accelerated Life Testing, Ahmed Mohamed Eshebli

Doctoral Dissertations

"Accelerated life testing (ALT) is utilized to estimate the underlying failure distribution and related parameters of interest in situations where the components under study are designed for long life and therefore will not yield failure data within a reasonable test period. In ALT, life testing is carried out under two or more higher than normal stress levels, with the resulting acceleration of the failure process yielding a sufficient amount of un-censored life-span data within a practical test duration. Usually one (or more) parameters of the life distribution is linked to the stress level through a suitably selected model based on …

A Functional Data Analytic Approach For Region Level Differential Dna Methylation Detection, Mohamed Salem F. Milad

Doctoral Dissertations

"DNA methylation is an epigenetic modification that can alter gene expression without a DNA sequence change. The role of DNA methylation in biological processes and human health is important to understand, with many studies identifying associations between specific methylation patterns and diseases such as cancer. In mammals, DNA methylation almost always occurs when a methyl group attaches to a cytosine followed by a guanine (i.e. CpG dinucleotides) on the DNA sequence. Many statistical methods have been developed to test for a difference in DNA methylation levels between groups (e.g. healthy vs disease) at individual cytosines. Site level testing is often …

Event-Triggered Near Optimal Adaptive Control Of Interconnected Systems, Vignesh Narayanan

Doctoral Dissertations

"Increased interest in complex interconnected systems like smart-grid, cyber manufacturing have attracted researchers to develop optimal adaptive control schemes to elicit a desired performance when the complex system dynamics are uncertain. In this dissertation, motivated by the fact that aperiodic event sampling saves network resources while ensuring system stability, a suite of novel event-sampled distributed near-optimal adaptive control schemes are introduced for uncertain linear and affine nonlinear interconnected systems in a forward-in-time and online manner.

First, a novel stochastic hybrid Q-learning scheme is proposed to generate optimal adaptive control law and to accelerate the learning process in the presence of …

Reliability Prediction In Early Design Stages, Yao Cheng

Doctoral Dissertations

"In the past, reliability is usually quantified with sufficient information available. This is not only time-consuming and cost-expensive, but also too late for occurred failures and losses. For solving this problem, the objective of this dissertation is to predict product reliability in early design stages with limited information. The current research of early reliability prediction is far from mature. Inspired by methodologies for the detail design stage, this research uses statistics-based and physics-based methodologies by providing general models with quantitative results, which could help design for reliability and decision making during the early design stage. New methodologies which accommodate component …

Optimal Design And Freeform Extrusion Fabrication Of Functionally Gradient Smart Parts, Amir Ghazanfari

Doctoral Dissertations

"An extrusion-based additive manufacturing process, called the Ceramic On-Demand Extrusion (CODE) process, for producing three-dimensional ceramic components with near theoretical density was developed. In this process, an aqueous paste of ceramic particles with a very low binder content (<1 vol%) is extruded through a moving nozzle at room temperature. After a layer is deposited, it is surrounded by oil (to a level just below the top surface of most recent layer) to preclude non-uniform evaporation from the sides. Infrared radiation is then used to partially, and uniformly, dry the just-deposited layer so that the yield stress of the paste increases and the part maintains its shape. The same procedure is repeated for every layer until part fabrication is completed. Sample parts made of alumina and fully stabilized zirconia were produced using this process and their mechanical properties including density, strength, Young's modulus, Weibull modulus, toughness, and hardness were examined. Microstructural evaluation was also performed to measure the grain size, and critical flaw sizes were obtained. The results indicate that the proposed method enables fabrication of geometrically complex parts with superior mechanical properties. Furthermore, several methods were developed to increase the productivity of the CODE process and enable manufacturing of functionally graded materials with an optimum distribution of material composition. As an application of the CODE process, advanced ceramic components with embedded sapphire optical fiber sensors were fabricated and properties of parts and sensors were evaluated using standard test methods"--Abstract, page iv.

Studies On Neutron Diffraction And X-Ray Radiography For Material Inspection, Fahima Fahmida Islam

Doctoral Dissertations

"Among the different probes to study the structures of the bio and structural materials, X-ray and neutron are widely used because of their distinctive usefulness in investigating different structures. X-ray radiography and neutron diffraction are two widely known non-destructive techniques for material inspection. Here we demonstrate the design of neutron diffractometer with low power source and analyze the digital image produced by the X-ray radiography instead of neutron diffraction because of the availability of the data. Neutron diffraction is a powerful tool for understanding the behavior of crystal structures and phase behaviors of materials. While neutron diffraction capabilities continue to …

Thermomechanical Fatigue Life Investigation Of An Ultra-Large Mining Dump Truck Tire, Wedam Nyaaba

Doctoral Dissertations

The cost benefits associated with the use of heavy mining machinery in the surface mining industry has led to a surge in the production of ultra-large radial tires with rim diameters in excess of 35 in. These tires experience fatigue failures in operation. The use of reinforcing fillers and processing aids in tire compounds results in the formation of microstructural inhomogeneity in the compounds and may serve as sources of crack initiation in the tire. Abrasive material cutting is another source of cracks in tires used in mining applications. It suffices, then, to assume that every material plane in the …

Gamma Spectroscopy By Artificial Neural Network Coupled With Mcnp, Huseyin Sahiner

Doctoral Dissertations

"While neutron activation analysis is widely used in many areas, sensitivity of the analysis depends on how the analysis is conducted. Even though the sensitivity of the techniques carries error, compared to chemical analysis, its range is in parts per million or sometimes billion. Due to this sensitivity, the use of neutron activation analysis becomes important when analyzing bio-samples. Artificial neural network is an attractive technique for complex systems. Although there are neural network applications on spectral analysis, training by simulated data to analyze experimental data has not been made. This study offers an improvement on spectral analysis and optimization …

The Effect Of Testing Conditions On Lost Circulation Materials' Performance In Simulated Fractures, Montri Jeennakorn

Doctoral Dissertations

"Lost circulation (LOC) problems increase costs of drilling significantly. It is not only the cost of the drilling fluid that is lost into the formation but also the costs of subsequent problems that can be higher than the cost of the drilling fluids. LOC also possibly leads to a serious risk of blowout incident.

Lost circulation materials (LCM) are regularly added to the drilling fluids with an expectation of plugging the flow path. Due to the difficulties of testing and monitoring LCM sealing processes in the field, LCM evaluation in the laboratory is often used to prove and assure successful …

Modeling Dynamic Community Acceptance Of Mining Using Agent-Based Modeling, Mark Kofi Boateng

Doctoral Dissertations

"This research attempts to provide fundamental understanding into the relationship between perceived sustainability of mineral projects and community acceptance. The main objective is to apply agent-based modeling (ABM) and discrete choice modeling to understand changes in community acceptance over time due to changes in community demographics and perceptions. This objective focuses on: 1) formulating agent utility functions for ABM, based on discrete choice theory; 2) applying ABM to account for the effect of information diffusion on community acceptance; and 3) explaining the relationship between initial conditions, topology, and rate of interactions, on one hand, and community acceptance on the other …

Experimental Study Of Natural Convection Heat Transfer And Gaseous Dynamics From Dual-Channel Circulation Loop, Ibrahim Ahmed Said Abdallah

Doctoral Dissertations

"This research focuses on establishing a range of scaled separate and integral effects experiments for studying thermal-hydraulic behavior occurring within a component or region of the prismatic very high-temperature reactor (VHTR) such as plenum-to-plenum heat transfer and gaseous dynamics during natural circulation. Natural circulation of the coolant is the leading capability for VHTR to transport the decay heat from the core to the reactor vessel during accident scenarios. To address this need, a scaled-down facility is designed and developed with only two channels with upper and lower plena. The emphasis is placed on high-resolution and high-fidelity experimental data for local …

Pillar Design For St. Peter Sandstone Formation, Francis Anohomah Arthur

Doctoral Dissertations

"Silica sands produced primarily from St. Peter Sandstone are used for hydraulic fracturing in the petroleum industry, glassmaking, chemicals, ceramics, filtration and the foundry industry in the US. The recent high demand for silica sands for hydraulic fracturing has triggered increased production and commissioning of new silica sand mines to support natural gas production from shale and tight gas deposits in the US. Most mines use surface mining methods to extract St. Peter Sandstone. The room and pillar mining method has been successfully used for St. Peter Sandstone mining in a few US locations, however, no one has proposed a …

Theoretical Calculations For Electron Impact Ionization Of Atoms And Molecules, Sadek Mohamed Fituri Amami

Doctoral Dissertations

"In the last twenty years, significant progress has been made for the theoretical treatment of electron impact ionization (e,2e) of atoms and molecules and, for some cases, very nice agreement between experiment and theory has been achieved. In particular, excellent agreement between theory and experiment and theory has been achieved for ionization of hydrogen and helium. However, agreement between experiment and theory is not nearly as good for ionization of larger atoms and molecules. In the first part of this dissertation, different theoretical approaches will be employed to study the triply differential cross section (TDCS) for low and intermediate energy …