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Full-Text Articles in Engineering

Non-Hydrostatic Models For Wave Propagation, Breaking, And Run-Up, Zhangping Wei Jan 2014

Non-Hydrostatic Models For Wave Propagation, Breaking, And Run-Up, Zhangping Wei

Electronic Theses and Dissertations

This dissertation develops a series of non-hydrostatic pressure wave models based on the finite element free surface flow model, CCHE2D, for simulating propagation, breaking, and run-up of coastal wave processes. The first non-hydrostatic formulation presented in this dissertation directly introduces a non-hydrostatic pressure module into CCHE2D. An edge-based pressure allocation method is implemented, and a depth-integrated vertical momentum equation is introduced. The depth-integrated horizontal momentum equations are solved for a provisional velocity field, and then the non-hydrostatic pressure is obtained by satisfying the divergence-free velocity field condition, subsequently the velocity field is corrected by the non-hydrostatic pressure. Finally the free …


Geotechnical Technique To Strengthen Traditional I-Walls Through The Use Of Composite Material, Jimmy Irby Jackson Jan 2013

Geotechnical Technique To Strengthen Traditional I-Walls Through The Use Of Composite Material, Jimmy Irby Jackson

Electronic Theses and Dissertations

On Monday, August 29, 2005, Hurricane Katrina struck the southern gulf coast of the United States. Hurricane Katrina produced record high amounts of surge water along the coastal regions, that over topped and eroded levees and flood walls, inevitably flooding the entire city of New Orleans. After Hurricane Katrina, the Department of Homeland Security approved a research grant to The University of Mississippi to develop effective but economic technique of strengthening existing I-walls. Using composite materials, a new retrofitting technique was developed to increase the stability of existing I-walls by implementing composite caps. For economical and practical testing, scale models …


Mechanical Properties Of Portland Cement And Its Constituents At The Nano-Level, Brent French Jan 2013

Mechanical Properties Of Portland Cement And Its Constituents At The Nano-Level, Brent French

Electronic Theses and Dissertations

The following is a summary of research for a portion of the project titled Nano to Continuum Multi-Scale Modeling Techniques and Analysis For Cementitious Materials Under Dynamic Loading in association with North Carolina Agricultural & Technical State University and the US Army. This research investigates several attempts at creating a better Portland cement model at the atomistic level through molecular dynamics simulations. These models are modified to simulate damage to the basic cement structure, and are simulated using several combinations of forcefields and molecular dynamics tools. Experimental techniques such as nanoindentation, atomic force microscopy, and x-ray diffraction are applied to …


Physical, Mechanical And Chemical Aging Of Polyurea Nanocomposites, Ghanshyam Pal Jan 2013

Physical, Mechanical And Chemical Aging Of Polyurea Nanocomposites, Ghanshyam Pal

Electronic Theses and Dissertations

Two component polyurea systems, on one hand, are gaining popularity as corrosion and abrasion resistant coatings and linings while on the other hand there are a few polyurea compositions being used as barrier against blast and ballistic threats to protect nation's critical infrastructure. Physical properties of polymer composites can be tailored with appropriate choice of type, size and amount of reinforcement. In general, nano-sized reinforcements provide better reinforcing over conventional reinforcements due to higher surface to volume ratio. In this dissertation, the first aim is to study effect of nanoreinforcement addition on the overall character (mechanical, chemical and microstructural) of …


Nanoenhanced Polyurea As A Blast Resistant Coating For Concrete Masonry Walls, Heather Kathryn Daniell Rivera Jan 2013

Nanoenhanced Polyurea As A Blast Resistant Coating For Concrete Masonry Walls, Heather Kathryn Daniell Rivera

Electronic Theses and Dissertations

Blast impact is a major concern in the world today. The leading cause of death due to blast impacts is rapidly moving debris. To prevent this many researchers are looking for methods of improved blast resistance for concrete masonry walls. However, many available protective coatings are not flame retardant. This thesis focuses on nanoenhanced polyurea for applications in improving blast resistance, while possessing improved flame retardancy, of concrete masonry walls. The polyurea that is being researched is enhanced with nanoadditives in an effort improve both blast and fire resistance. These materials are dynamically tested and those showing marked improvement are …


3-D Numerical Simulation Of Dam-Break Flows Over Movable Beds, Reza Marsooli Jan 2013

3-D Numerical Simulation Of Dam-Break Flows Over Movable Beds, Reza Marsooli

Electronic Theses and Dissertations

Irvin Cooper was a prominent music educator in boys’ adolescent voice change research. Dr. Cooper developed the Cambiata concept as a method for teaching boys to sing throughout the voice change. This method was starkly different from the traditional model that encouraged the changing voice to be rested during the voice change. While working as the music supervisor for the Montreal protestant school system, Cooper developed his method of having boys sing during the voice change, which included arrangements and compositions specifically for changing voices. Cooper taught many prominent researchers of adolescent voice change, including Don Collins and John Cooksey. …


Fe Modeling In Support Of Vibration Based Damage Detection In Bridges, James Kyle Bethay Jan 2013

Fe Modeling In Support Of Vibration Based Damage Detection In Bridges, James Kyle Bethay

Electronic Theses and Dissertations

Vibration based damage detection in bridges is examined with the objective of defining a relationship between substructure stiffness degradation and frequency and mode shape modulation induced by damage. The relationship is explored through finite element modeling of primarily an experimental representation of a three-span concrete bridge structure located at the entrance to the main campus of The University of Mississippi in Oxford. Equivalent beam and 3D finite element models are created of an experimental setup incorporating levels of damage simulated using deck slab bearing pads of varying stiffness. Eigenvalue analysis is performed to examine the change of frequencies for characteristic …


Geospatial Assessment Of Sustainable Built Infrastructure Assets And Flood Disaster Protection, Alper Durmus Jan 2012

Geospatial Assessment Of Sustainable Built Infrastructure Assets And Flood Disaster Protection, Alper Durmus

Electronic Theses and Dissertations

This research was initiated with a review and synthesis of infrastructure related to city and urban growth, built infrastructure to meet transportation needs and travel demand, and role of mass transit in reducing adverse impacts on the environment and greenhouse gas emissions. Floods are the most frequently occurring natural disaster in the world, which so far claimed millions of lives and resulted in billion-dollar economic costs. Built infrastructure assets in urban and rural areas are not spared from floods' aftermath. A major motivation for this thesis was the 2011 megaflood disaster of Thailand which devastated the green campus of Asian …


Inspection Of Earthen Embankment Dams Using Time Lapse Electrical Resistivity Tomography, Jared Stewart Case Jan 2012

Inspection Of Earthen Embankment Dams Using Time Lapse Electrical Resistivity Tomography, Jared Stewart Case

Electronic Theses and Dissertations

According to the National Inventory of Dams (NID), the number of dams across the United States is approximately 85,000. Many of these dams are more than 50 years old and need vast attention to ensure their safety. It is difficult to obtain a full assessment of the dam just by visual inspections alone. This is because many problems associated with dam failure occur internally, which makes it difficult to be observed by the dam inspectors. Examples of these flaws are piping and seepage (flow of water through or around dam walls). It is in this area where geophysical methods can …


Finite Element Modeling Of Seismic Wave Propagation In Earthen Embankments, Binyam Tadese Jan 2012

Finite Element Modeling Of Seismic Wave Propagation In Earthen Embankments, Binyam Tadese

Electronic Theses and Dissertations

The detection of internal seepage zones in embankments (dams and levees) by geophysical seismic techniques such as seismic refraction is limited by a number of factors. Some factors are associated with inversion and smoothing problems during processing, while others are associated with the natural characteristics of embankments and seepage anomalies. In this research, changes in the seismic response associated with: embankment soil compositions and moisture, characteristics of the seepage zone, presence of water in the reservoir, and shape of embankment was studied via 2D and 3D finite element (FE) embankment models. Artificial reflections from external boundaries and numerical dispersion were …


Developing A Retrofitting System To Mitigate Floodwall Failures Of New Orleans, James Tyler Kidd Jan 2011

Developing A Retrofitting System To Mitigate Floodwall Failures Of New Orleans, James Tyler Kidd

Electronic Theses and Dissertations

No abstract provided.


Seismic Tomography For The Integrity Assessment Of Earthen Dams And Levees., Leti Teklu Wodajo Jan 2011

Seismic Tomography For The Integrity Assessment Of Earthen Dams And Levees., Leti Teklu Wodajo

Electronic Theses and Dissertations

Dams are a vital part of a nation's infrastructure. Considering the fact that many of the dams in the United States have approached or are approaching their projected life expectancy of 50 years, these critical infrastructures represent a risk to public safety. Minimizing this risk requires an ongoing safety inspection, monitoring, maintenance and rehabilitation program. This research examines the use of a non-invasive geophysical seismic method to provide additional information where the usual visual inspection is insufficient and the comboring investigation is not an option. Even though seismic techniques provide valuable information of the subsurface strata, the interpretation is not …


Column Capacity Evaluation For Low-Rise Moment Frame Steel Buildings In Mississippi Subject To Wind And Seismic Hazards, Yihong Shi Jan 2011

Column Capacity Evaluation For Low-Rise Moment Frame Steel Buildings In Mississippi Subject To Wind And Seismic Hazards, Yihong Shi

Electronic Theses and Dissertations

For the design of steel frame structures, AISC outlines approaches of second-order analysis. In this study, two of these approaches are considered: Amplified First-Order Analysis Method and Direct Analysis Method. The methods were studied using SAP2000. Amplification of moments in a two-story plane frame subject to a wind load case is computed using both methods and shown to be of comparable magnitude for small deformations. ASCE/SEI 7 and IBC provisions were used to develop lateral design load conditions for the frames. In this study, a hypothetical building was assumed to be constructed in four different locations (Southaven, Batesville, Jackson and …


Experimental Damage Diagnosis Of A Model Three-Story Spatial Frame, Samantha Sabatino Jan 2011

Experimental Damage Diagnosis Of A Model Three-Story Spatial Frame, Samantha Sabatino

Electronic Theses and Dissertations

Structural damage can be induced by a variety of events from short-term abnormal stresses to long-term natural aging. Detection of changes in a structure's ability to withstand subsequent loads can aid decisions on safety, repair, rehabilitation, and demolition. Dynamic property shifts can show internal cracks and minor damage before propagation or failure occurs, but only if a proper indicator is selected. In order to evaluate potential damage indices, a three-story metal frame building was constructed. Using Star Modal software, dynamic structural properties were obtained from modal decomposition on experimental tap test responses. The natural frequencies and mode shapes of the …


Modeling Of Transient Response Of An Elastic Beam With Flexible Supports And Variable-Location Impact, Weiping Xu Jan 2010

Modeling Of Transient Response Of An Elastic Beam With Flexible Supports And Variable-Location Impact, Weiping Xu

Electronic Theses and Dissertations

This research is prerequisite to determining structural health and estimating wear-limited life of contact/impact machinery components. Prevention, or at least early notification, of impact-induced wear is essential for preventing economic loss and enhancing personnel safety. Thus, an efficient model which is discrete in time and continuous in space was undertaken; an euler-bernoulli beam with adjustable boundary conditions and variable impact is numerically studied under a pulse loading. Structural stiffness, material modulus, contact stiffness, contact location, damping ratio, pulse duration, clearance and boundary conditions are investigated. A reference system is used as the basis for parameter studies and solution convergence is …