Physical Sciences and Mathematics Commons^™

Deep Learning-Based Surrogate Models For Post-Earthquake Damage Assessment, Xinzhe Yuan

Doctoral Dissertations

"Seismic damage assessment is a critical step to enhance community resilience in the wake of an earthquake. This study aims to develop deep learning-based surrogate models for widely used fragility curves to achieve more accurate and rapid assessment in practice. These surrogate models are based on artificial neural networks trained from the labelled ground motions whose resulting damage classes on targeted structures are determined by nonlinear time history analyses. The development of various surrogate models is progressed in four phases. In Phase I, the multilayer perceptron (MLP) is used to develop multivariate seismic classifiers with up to 50 hand-crafted intensity …

Reveal Wind Loading Of Tornadoes And Hurricanes On Civil Structures Towards Hazard-Resistant Design, Ryan Honerkamp

Doctoral Dissertations

"Extreme winds impacting civil structures lead to death and destruction in all regions of the world. Specifically, tornadoes and hurricanes impact communities with severe devastation. On average, 1200 tornadoes occur in the United States every year. Tornadoes occur predominantly in the Central and Southeastern United States, accounting for an annual $1 billion in economic losses, 1500 injuries, and 90 deaths. The Joplin, MO Tornado in 2011 killed 161 people, injured more than 1000, destroyed more than 8000 structures, and caused $2.8 billion of property loss. Hurricanes occur predominantly on the United States East coast regions and along the coast of …

Exposure Assessment Of Emerging Contaminants: Rapid Screening And Modeling Of Plant Uptake, Majid Bagheri

Doctoral Dissertations

"With the advent of new chemicals and their increasing uses in every aspect of our life, considerable number of emerging contaminants are introduced to environment yearly. Emerging contaminants in forms of pharmaceuticals, detergents, biosolids, and reclaimed wastewater can cross plant roots and translocate to various parts of the plants. Long-term human exposure to emerging contaminants through food consumption is assumed to be a pathway of interest. Thus, uptake and translocation of emerging contaminants in plants are important for the assessment of health risks associated with human exposure to emerging contaminants. To have a better understanding over fate of emerging contaminants …

Studying The Effects Of Various Process Parameters On Early Age Hydration Of Single- And Multi-Phase Cementitious Systems, Rachel Cook

Doctoral Dissertations

”The hydration of multi-phase ordinary Portland cement (OPC) and its pure phase derivatives, such as tricalcium silicate (C₃S) and belite (ß-C₂S), are studied in the context varying process parameters -- for instance, variable water content, water activity, superplasticizer structure and dose, and mineral additive type and particle size. These parameters are studied by means of physical experiments and numerical/computational techniques, such as: thermodynamic estimations; numerical kinetic-based modelling; and artificial intelligence techniques like machine learning (ML) models. In the past decade, numerical kinetic modeling has greatly improved in terms of fitting experimental, isothermal calorimetry to kinetic-based modelling …

Seismic Behavior Of Composite Bridge Columns, Mohanad M. Abdulazeez

Doctoral Dissertations

“This study investigates experimentally and numerically the seismic behavior of large-scale hollow-core fiber-reinforced polymer-concrete-steel (HC-FCS) innovative bridge columns as a sustainable approach to endure and rapidly recover from natural disasters such as earthquakes. The HC-FCS column consisted of a concrete shell sandwiched between an outer fiber-reinforced polymer (GFRP) tube and an inner steel tube to provided continuous confinement for the concrete shell along with the height of the column. The columns have a slender inner steel tube with diameter-to-thickness (D_s/t_s) ratios ranged between 85 to 254. Each steel tube was embedded into the footing, while the …

Minimizing The Detrimental Effects Of Hydro-Peaking On Riverbank Instability: The Lower Osage River Case, Wesam Sameer Mohammed-Ali

Doctoral Dissertations

"The fluctuation of water level downstream from dams due to hydropower flow releases negatively affects the riverbank stability. Therefore, this research aims to examine the feasibility of using an optimization technique to mitigate the riverbank instability resulting from the outflow variation of hydropower plants. The effects of the water releases from the Bagnell Dam were investigated by computing a series of safety factors for 78 cross sections along the 81-mile stretch of the lower Osage River in relation to outflow events by using the integrated BSTEM model incorporated into the HEC-RAS model. The 1-D sediment transport and unsteady flow in …

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 …

Imaging The Subsurface In Eastern Part Of Lake Chesterfield Using A Combination Of Geophysical Tools, Jiawei Li

Masters Theses

"The Lake Chesterfield North Dam in Wildwood city, Missouri has been leaking, more or less continuously since the dam was constructed in 1986 despite mitigation efforts in 1988, 1994, 1995, 2004, and 2005. Neither the grouting efforts in 1988, 1994, 1995, 2004 or 2005, nor the placement and rehabilitation of an impervious clay liner in 2005 has solved the problem. Indeed, in June of 2017, the water level in Lake Chesterfield dropped at an alarmingly rapid rate.

Prior to authorizing additional mitigation work, the Lake Chesterfield Home Owners Association (LCHOA) decided to acquire geophysical data across the dry lake bed. …

Numerical Modeling Of Capillary-Driven Flow In Open Microchannels: An Implication Of Optimized Wicking Fabric Design, Mehrad Gholizadeh Ansari

Masters Theses

"The use of microfluidics to transfer fluids without applying any exterior energy source is a promising technology in different fields of science and engineering due to their compactness, simplicity and cost-effective design. In geotechnical engineering, to increase the soil's strength, hydrophilic wicking fibers as type of microfluidics have been employed to transport and drain water out of soil spontaneously by taking advantage of natural capillary force without using any pumps or other auxiliary devices. The objective of this study is to understand the scientific mechanisms of the capability for wicking fiber to drain both gravity and capillary water out of …

Dragline Excavation Simulation, Real-Time Terrain Recognition And Object Detection, Godfred Somua-Gyimah

Doctoral Dissertations

"The contribution of coal to global energy is expected to remain above 30% through 2030. Draglines are the preferred excavation equipment in most surface coal mines. Recently, studies toward dragline excavation efficiency have focused on two specific areas. The first area is dragline bucket studies, where the goal is to develop new designs which perform better than conventional buckets. Drawbacks in the current approach include operator inconsistencies and the inability to physically test every proposed design. Previous simulation models used Distinct Element Methods (DEM) but they over-predict excavation forces by 300% to 500%. In this study, a DEM-based simulation model …

Cloth-Air Partitioning Of Oxybenzone, Jonathan T. Hill

Masters Theses

"Clothing has been proven to be a significant accumulator of chemicals from the air. Semi-volatile organic compounds (SVOCs) have a high affinity towards textiles, and measuring the equilibrium partition coefficient between cloth and air (K_cloth-air) for SVOCs is crucial in predicting human exposure to these compounds. This study aims to quantify K_cloth-air for oxybenzone to contribute to a larger human exposure experiment carried out at the Technical University of Denmark (DTU). K_cloth-air for oxybenzone was calculated using data collected from the exposure chamber at DTU and from performing extractions of oxybenzone in fabric samples from the …

In-Situ Assessment Of Concrete Bridge Decks And Pavements Using Stress-Wave Based Methods, Mengxing Li

Doctoral Dissertations

"Concrete infrastructure of United States is aging and deteriorating. Accurate assessment the condition of concrete infrastructure is critical for its maintenance and rehabilitation. Stress-wave based methods, including ultrasonic surface wave (USW) and impact echo (IE), are becoming popular for characterizing defects and mechanical properties of concrete infrastructures. In this dissertation, a comprehensive literature review of seismic wave theory and common types of defects identified in concrete infrastructures, as well as stress-wave based methods used for concrete infrastructure monitoring and characterizing on a selected concrete bridge deck and two concrete pavement segments are present. The utility and reliability of both methods …

Imaging In Karst Terrain Using The Electrical Resistivity And Multichannel Analyses Of Surface Wave Methods, Ragab W. Jaafar

Masters Theses

"Electrical resistivity tomography and multi-channel analyses of surface waves data were acquired at a study area in Phelps County in the south-central part of Missouri. The objectives of the investigation were fourfold: 1) to image the subsurface in the study area to a depth of 70 feet; 2) to compare the ERT images generated using both the dipole-dipole and Wenner-Schlumberger arrays; and 3) to assess how variations in the MASW array configuration affected MASW data quality; and 4) to compare the ERT-estimated depth to top-of-rock and the MASW-generated depth to top-of-rock.

The subsurface in the study area was imaged to …

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 …

Assessment Of Rockfall Rollout Risk Along Varying Slope Geometries Using The Rocfall And Crsp Software, Mariam S. Al E'Bayat

Masters Theses

"Most routes in mountainous areas suffer from rock falling, rolling and bouncing risk. There are many computer programs concerned with simulating the rockfall problem, and whereas they have the same purpose, they however differ in the input data that's needed to simulate the problem, and they also differ in the way of processing and kind of output.

This study used Rocfall® and the Colorado Rockfall Simulation Program (CRSP®) to simulate sixty-three models of varying slope geometry, where only the slope geometry is changed with the same material properties for both the slope and the rocks.

Both programs were fast and …

Phytoforensics: Applications In Vapor Intrusion Assessment, Jordan Lee Wilson

Doctoral Dissertations

"Vapor intrusion (VI) occurs when contaminants in the vapor phase migrate in the shallow subsurface and enter buildings through cracks, seams, and gaps and has been recognized as a serious human-health threat as occupants are exposed to potentially harmful concentrations over long periods of time. The VI pathway has recently (2017) been identified as a primary exposure pathway and implemented into the Hazard Ranking System for inclusion on the Nation Priorities List. However, assessing VI and human exposure is not simple and current methods are time-, cost-, and labor-intensive; intrusive; and temporally and spatially variability. Trees are ideal candidates for …

Phytoforensics Tools: The Degradation And Detection Of Chlorinated Solvents In Integrated Systems, Tommy J. Goodwin Jr.

Masters Theses

"Due to decades of mismanaged pollutants entering groundwater, subsurface pollution of various compounds has become a widespread challenge. Chlorinated solvents are the most common groundwater contaminants that persist in aquifers, and remediation of these wide-spread plumes is difficult. Bioremediation, permeable reactive barriers, and phytoremediation are remedial technologies that have been developed and applied to chlorinated solvents in groundwater systems. This study integrates these technologies in different combinations to demonstrate the remediation potential of this approach. Zerovalent iron (ZVI) and bioaugmentation with a Dehalococcoides sp. (DHC) culture were applied separately and in combination for degradation of perchloroethene (PCE). Salix pentandra were …

Assessing Downstream Stormwater Impacts For Urban Watershed Planning, Johanna Meyer Pavlowsky

Masters Theses

"The urbanization of watersheds has caused debilitating effects to downstream aquatic ecosystems in catchments and streams. The implementation of green infrastructure (GI), such as permeable pavements and bioretention facilities, has been shown to alleviate these effects by both reducing runoff and mitigating pollutants; however, the implements are often not designed with a specific goal of water improvement. This study targets understanding a small, impaired urban watershed, and the benefits green infrastructure may have to provide environmental, social, and economic improvement to the watershed.

Portions of Rolla including much of the S&T campus drain into the impaired urban waterbody Frisco Lake, …

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 …

Comprehensive Benefits Of Green Roofs, Madison R. Gibler

Masters Theses

"Green infrastructure uses vegetation, soils, and natural processes to manage water and create healthier urban environments, providing traditional roof services and alternative stormwater management technologies. Other benefits and impacts are not yet fully understood or valued. Research conducted assesses specific stormwater benefits of green roofs, providing information on nutrient leaching from media; and analyzes potential energy benefits through side-by-side comparisons of full-scale white, traditional black rubber, and green roofs in the mid-continent Missouri climate. Roofing media selection impacted leaching of nutrients, suspended solids, and organic carbon from the tested green roof media. Thermal properties were investigated at the building level, …

Dynamic Behavior Of Operational Wind Turbines Considering Aerodynamic And Seismic Load Interaction, Mohammad-Amin Asareh

Doctoral Dissertations

"With the advancements in the wind energy production industry, the demand for a cost effective and safe design of wind turbine structures is growing rapidly. The wide deployment of wind turbines in locations with high seismic hazard has lead engineers to take into account a more comprehensive seismic design of such structures. In response to the need for a computational tool that can perform coupled simulations of wind and seismic loads, a seismic module has been developed for the publicly available National Renewable Energy Laboratory (NREL) code, FAST, at the first step of this research. This achievement allows engineers working …

Performance Analysis And Modelling Of Hybrid Photovoltaic-Thermal Solar Panels, Nicole C. Annis

Doctoral Dissertations

A photovoltaic-thermal (PVT) panel was constructed, tested, and modelled using both MATLAB and TRNSYS. During the experimental testing, which took place on the Missouri University of Science and Technology campus in Rolla, Missouri; two identical PVT panels were tested alongside two PV panels to gather an electrical baseline for comparison. Approximately 69 days’ worth of data were of data were collected during the summer of 2014. The PV electrical, PVT electrical, PVT thermal and PVT combined (electrical and thermal) efficiencies were 3.5-5.6%, 3.4-5.4%, 20.9-11.6%, and 24.3-17.0%, respectively.

A MATLAB program was developed using existing equations for one-dimensional, quasi-steady model of …

Advanced Sustainable Concrete Materials For Infrastructure Applications, Kaylea Ann Smith

Masters Theses

"This study was performed to examine the effects of cement replaced by high volumes of Class C fly-ash on durability characteristics of concrete up to 120 days. Specifically, this study investigates possibility of amending American Society for Testing and Materials (ASTM) to allow High Volume Fly-ash (HVFA) concrete to cure until later ages prior to testing instead of 28 days. Five mix designs were compared with varying fly-ash percentages from 0 to 70% (by total cementitious mass). No other additives were present in any of the five mix designs. Water-to-cementitious ratio (w/cm) and total cementitious material remained constant as 0.40 …

Mechanical Characteristics Of Organically Modified Fly Ash-Kaolinite Mixtures, Xin Kang

Doctoral Dissertations

"Fly ash is a hazardous waste material to the environment. Beneficial reuse of fly ash, however, brings economic and environmental benefits, i.e., decreases the cost of disposal, reduces greenhouse gas emission, and improves mechanical properties of construction materials. Due to the lack of pozzolanic properties, the reuse rate of Class F fly ash in geotechnical engineering is relatively low (ACAA 2013). In order to promote the effectiveness and sustainability of high volume reuse of class F fly ash in geotechnical engineering, biopolymers (Chitosan, and Xanthan gum) and synthetic polymers (Polyethylene Oxide, PEO) were used instead of the traditional stabilizers to …

Assessment Of Contributing Factors To The Reduction Of Diarrhea In Rural Communities Of Para, Brazil, Lee Voth-Gaeddert

Masters Theses

"In developing communities the occurrence of diarrhea has been reported at elevated levels as compared to those communities in more developed regions. Diarrheal diseases were linked to over one million deaths in 2012 throughout the world. While multiple pathways are present for the transmission of diarrheal diseases, water has been the focus for many aid organizations. Point-of-use (POU) water treatment methods are a common tool used by aid organizations in efforts to provide potable water. The CAWST biosand filter is a POU tool that has shown removal effectiveness of pathogenic microorganisms ranging from 90-99%. However, minimal literature was found that …

Water Resources Development -- An Analysis Of Economic Justification Practices Of The Corps Of Engineers, Kerwood W. Barrand

Masters Theses

"Presented herein is a brief analysis of the economic justification practices of the Corps of Engineers as commonly implemented in proposals concerning water resources projects. Where applicable, recommended methods are compared to similar methods advocated for, and accepted by, private engineering firms in similar situations.

The major problem exists in the lack of a profit motive in programs undertaken with the use of public funds. However, a profit can be said to have been realized in public works programs if the total benefits of the programs to all the people exceed the costs of these programs and, further, if the …