Engineering Commons^™

Continuous Focusing And Separation Of Microparticles With Acoustic And Magnetic Fields, Ran Zhou

Doctoral Dissertations

"Microfluidics enables a diverse range of manipulations (e.g., focusing, separating, trapping, and enriching) of micrometer-sized objects, and has played an increasingly important role for applications that involve single cell biology and the detection and diagnosis of diseases. In microfluidic devices, methods that are commonly used to manipulate cells or particles include the utilization of hydrodynamic effects and externally applied field gradients that induce forces on cells/particles, such as electrical fields, optical fields, magnetic fields, and acoustic fields.

However, these conventional methods often involve complex designs or strongly depend on the properties of the flow medium or the interaction between the …

The Influence Of Caprock On Blast Fragmentation Distribution, Matthew Kurtis Coy

Doctoral Dissertations

"This dissertation describes the development of a small-scale model of a caprock-laden quarry blast and discusses the results from that testing. The purpose of this testing was to provide insight into the reasons for poor caprock breakage during blasting.

Small-scale test blocks were poured using a weak mortar mix to represent a limestone formation at a small scale. A cold joint was created in the upper portion of the test specimens to represent the bedding plane that separates caprock and substrate layers in a caprock-laden limestone bench. The scale-model test blocks were blasted using detonating cord. The primary configuration for …

Emi Measurement And Modeling Techniques For Complex Electronic Circuits And Modules, Satyajeet Shinde

Doctoral Dissertations

"This dissertation consists of four papers. In the first paper, a combined model for predicting the most critical radiated emissions and total radiated power due to the display signals in a TV by incorporating the main processing board using the Huygens Equivalence theorem and the radiation due to the flex cable based on active probe measurements was developed.

In the second paper, a frequency-tunable resonant magnetic field probe was designed in the frequency range 900-2260 MHz for near-field scanning applications for the radio frequency interference studies by using a varactor diode providing the required capacitance and the parasitic inductance of …

Programming Problems On Time Scales: Theory And Computation, Rasheed Basheer Al-Salih

Doctoral Dissertations

"In this dissertation, novel formulations for several classes of programming problems are derived and proved using the time scales technique. The new formulations unify the discrete and continuous programming models and extend them to other cases "in between." Moreover, the new formulations yield the exact optimal solution for the programming problems on arbitrary isolated time scales, which solve an important open problem. Throughout this dissertation, six distinct classes of programming problems are presented as follows. First, the primal as well as the dual time scales linear programming models on arbitrary time scales are formulated. Second, separated linear programming primal and …

Dirac Surface States Of Magnetic Topological Insulators, Seng Huat Lee

Doctoral Dissertations

"Magnetic topological insulator (TI) has been theoretically proposed to be a platform for inducing magnetic monopole and exhibit fascinating quantum phenomena, whereas topological superconductor can host Majorana fermions, particles that are their own antiparticles, which can be manipulated for topological quantum computing. In this dissertation, we experimentally demonstrated that by intercalation of different transition metals in the van der Waals gaps of Bi₂Se₃ TI, magnetism and even superconductivity can be induced. In Fe_xBi₂Se₃, antiferromagnetism is induced with a transition temperature at ~ 100 K. Coexistence of the Dirac surface state with …

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 …

Acquisition Of Active Multichannel Analysis Of Surface Waves (Masw) Data In Karst Terrain, Ghassan Salem Alsulaimani

Doctoral Dissertations

"This study was designed to verify the effects and data reproducibility when the length of receiver array, receiver spacing, source offset and array orientation parameters are changed for data acquired using multichannel analysis of surface waves (MASW), at intended target depth of 30ft (9m), and to compare the results with electrical resistivity tomography (ERT) data obtained for the same study site.

The MASW data acquired for 34 sites, along four profiles for each site using variable source offsets of 10ft (3m) and 30ft (9.1m), and variable receiver spacings of 2.5ft (0.76m) and 5.0ft (0.76m), concurrently. Out of the 272 profiles …

Numerical And Experimental Study Of New Designs Of All-Vanadium Redox Flow Batteries For Performance Improvement, Mohammed Abdulkhabeer Ali Al-Yasiri

Doctoral Dissertations

"Energy storage is envisioned as a key part of a renewable energy solution incorporated in a grid that overcomes two critical limits of renewable energy: intermittency and uncertainty. Among various technologies, a vanadium redox flow battery (VRFB) offers a promise because of its unique features such as long cycle life, separation of energy and power ratings, and capability of a deep discharge. The remaining challenges, however, include the limited application due to low energy density and complicated geometries. The complex geometry makes it difficult to optimize the performance and can cause a serious concern about leakage of the liquid. The …

Long-Period Fiber Grating Corrosion Sensors For Life-Cycle Monitoring And Assessment Of Reinforced Concrete Structures, Yizheng Chen

Doctoral Dissertations

"This study aims to: (1) explore, develop, calibrate and validate Fe-C coated, long period fiber grating (LPFG) sensors for short-term mass loss measurement of the Fe-C coating; (2) develop, calibrate, and validate steel tube-encapsulated, fiber optic probes and LPFG sensors for long-term mass loss detection of the steel tube; (3) correlate the corrosion process of packaging metal materials with that of steel bars in direct contact with the packaged probe or sensor except for a thin insulation tape; and (4) apply both types of corrosion sensors into reinforced concrete (RC) structures for reinforcing bar corrosion monitoring and structural condition assessment. …

Investigation Of Hydraulic Fracture Complexity And The Benefits Of Maximizing Or Minimizing Complexity In Unconventional Resources, Rashid Sheikh Kassim

Doctoral Dissertations

"This dissertation discusses two separate, yet inter-related studies. The first study was an extension of historical work comparing transversely fractured versus longitudinally fractured horizontal wells in multiphase flow environment. The second study investigated hydraulic fracture complexities and the benefits of maximizing or minimizing complexities in unconventional resources and tight reservoirs.

The main objective of this research was to investigate fracture complexity and its impact on well performance and economics. To achieve that objective, three different integrated completions and reservoir models were built. Two of the three models, a hybrid reservoir model and micro-seismic based SRV (stimulated reservoir volume) model, were …

Rock And Fluid Flow Characterization On Unconventional Reservoir Using Confocal-Laser-Microscopy And Micromodels, Songyuan Liu

Doctoral Dissertations

"Unconventional oil reservoirs have become significant sources of petroleum production and have even better potential in the future. Many unconventional oil systems consist of nanoscale pore throats, sub-micro-scale pores and micro-scale fractures that are significantly smaller than those from conventional reservoirs. To understand fluid flow behavior in unconventional reservoir, lab approaches were conducted using lab-on-chip method for the direct visualization of the water/oil flow in sub-micro-scale channels and the flow behavior with influence of surfactant and fractures.

In this work, tight sandstone thin slice was characterized using confocal-laser-microscope. Using designed micromodels, microscopic study of interface and residual oil distribution as …

Repair Of Metallic Components Using Hybrid Manufacturing, Renwei Liu

Doctoral Dissertations

"Many high-performance metal parts users extend the service of these damaged parts by employing repair technology. Hybrid manufacturing, which includes additive manufacturing (AM) and subtractive manufacturing, provides greater build capability, better accuracy, and surface finish for component repair. However, most repair processes still rely on manual operations, which are not satisfactory in terms of time, cost, reliability, and accuracy. This dissertation aims to improve the application of hybrid manufacturing for repairing metallic components by addressing the following three research topics. The first research topic is to investigate and develop an efficient best-fit and shape adaption algorithm for automating 3D models' …

Manufacturing Of Advanced Continuous Fiber Reinforced Composites For High Temperature Applications, James Robert Nicholas

Doctoral Dissertations

"New resin systems have enabled composites to be considered as attractive alternatives in structural applications that require material to be stronger, lighter and/or more resilient to environmental effects. The current work is on the development of processes to produce continuous fiber reinforced materials from two state of the art resin systems. Two processes were developed to produce continuous fiber reinforced ceramic materials from a preceramic polymer. The first was a vacuum forming process developed using the out-of-autoclave polymer composite manufacturing technique in conjunction with the polymer infiltration and pyrolysis process to produce ceramic composite material of zirconium diboride-silicon carbide reinforced …

Engineering Advanced Adsorbent Materials For Co₂ Capture Applications, Harshul Thakkar

Doctoral Dissertations

"Global climate change due to the increasing CO₂ concentration in the atmosphere is primarily associated with anthropogenic CO₂ emissions. CO₂ capture technologies using adsorbents have not been implemented commercially due to lack of scalable, practical and cost-effective strategies and are still under development. Moreover, the use of conventional configurations such as pellets and beads for the removal of CO₂ from enclosed environments have been shown to impose limitations to the removal efficiency and system performance. In this dissertation, engineering of advanced and efficient structured adsorbents for practical and scalable CO₂ capture technologies and their use …

Imaging A Fly Ash Landfill Using Non-Invasive Technologies (Ert And Masw), Atiat Shaban Qasim Alsaaideh

Doctoral Dissertations

"Electrical resistivity tomography (ERT) data were acquired across a segment of an existing fly ash landfill in southwestern Missouri. The objective was to map potential karst features and identify probable groundwater seepage through and beneath the landfill.

Variations in the moisture content were mapped below and above the two liners (clay and synthetic) systems, the soil and bedrock. Seepage pathways were mapped through the fly ash and the underlying soil and rock. No visual evidence was found on any of the 3D ERT profiles of the presence of either pre-existing air-filled voids or pre-existing or newly infilled clay-filled voids. There …

Discrete Ordinates Ct Organ Dose Simulator (Doctors), Edward T. Norris

Doctoral Dissertations

"Computed tomography (CT) has become pervasive in medical diagnostics as improved imaging techniques and processing algorithms provide higher quality information to doctors. However, the exponentially increasing usage of CT has raised concerns regarding long term low-dose radiological risks.

Currently, the dose to patients is computed using Monte Carlo methods and experimental tests. In other areas of radiation transport, deterministic codes have been shown to be much faster than Monte Carlo codes.

Currently, no deterministic methodology exists to automatically generate a spatially distributed dose profile from a CT voxel phantom. This work proposes a new code, Discrete Ordinate CT Organ Dose …

Volumetric Error Compensation For 5-Axis Machine Tools, Jennifer Ruth Creamer

Doctoral Dissertations

"This work presents a geometric error compensation method for large 5-axis machine tools. The compensation method presented here uses tool tip measurements recorded throughout the axis space to construct a position-dependent geometric error model that can easily be used for error compensation. The measurements are taken using a laser tracker, permitting rapid error data gathering at most locations in the axis space. First two model types are compared for generating table-based error compensation and experimental results are presented. Table-based compensation is then extended to machine tool controller types with restrictions on the number or combination of compensation tables using an …

Quantitative Dependability And Interdependency Models For Large-Scale Cyber-Physical Systems, Koosha Marashi

Doctoral Dissertations

"Cyber-physical systems link cyber infrastructure with physical processes through an integrated network of physical components, sensors, actuators, and computers that are interconnected by communication links. Modern critical infrastructures such as smart grids, intelligent water distribution networks, and intelligent transportation systems are prominent examples of cyber-physical systems. Developed countries are entirely reliant on these critical infrastructures, hence the need for rigorous assessment of the trustworthiness of these systems. The objective of this research is quantitative modeling of dependability attributes -- including reliability and survivability -- of cyber-physical systems, with domain-specific case studies on smart grids and intelligent water distribution networks. To …

Survivability Modeling For Cyber-Physical Systems Subject To Data Corruption, Mark James Woodard

Doctoral Dissertations

"Cyber-physical critical infrastructures are created when traditional physical infrastructure is supplemented with advanced monitoring, control, computing, and communication capability. More intelligent decision support and improved efficacy, dependability, and security are expected. Quantitative models and evaluation methods are required for determining the extent to which a cyber-physical infrastructure improves on its physical predecessors. It is essential that these models reflect both cyber and physical aspects of operation and failure. In this dissertation, we propose quantitative models for dependability attributes, in particular, survivability, of cyber-physical systems. Any malfunction or security breach, whether cyber or physical, that causes the system operation to depart …

Control Of Single- And Dual-Probe Atomic Force Microscopy, Muthukumaran Loganathan

Doctoral Dissertations

“Atomic force microscope (AFM) is one of the important and versatile tools available in the field of nanotechnology. It is a type of probe-based microscopy wherein an atomically sharp tip, mounted on the free end of a microcantilever, probes the surface of interest to generate 3D topographical images with nanoscale resolution. An integral part of the AFM is the feedback controller that regulates the probe deflection in the presence of surface height changes, enabling the control action to be used for generating topographical image of the sample. Besides sensing, the probe can also be used as a mechanical actuator to …

Data Analysis And Application Guidelines Of Particle Gel Treatments, Yue Qiu

Doctoral Dissertations

“Water production is a severe worldwide issue in mature oilfields, which results in shortening the economic life of oil and gas wells. Particle gel have been widely applied in mature oilfields to improve reservoir sweep efficiency and control water production. To date, more than 10,000 injection wells were successfully treated by particle gels. However, considerable uncertainty still exists regarding to where and how particle gel treatments can be best applied.

The main objective of this study is to provide application guidelines and prediction model for particle gel treatments through data analysis. In this study, four particle gel treatment datasets have …

Analysis And Optimization Of Scientific Applications Through Set And Relation Abstractions, M. Tohid (Rastegar Tohid, Mohammed)

LSU Doctoral Dissertations

Writing high performance code has steadily become more challenging since the design of computing systems has moved toward parallel processors in forms of multi and many-core architectures. This trend has resulted in exceedingly more heterogeneous architectures and programming models. Moreover, the prevalence of distributed systems, especially in fields relying on supercomputers, has caused the programming of such diverse environment more difficulties. To mitigate such challenges, an assortment of tools and programming models have been introduced in the past decade or so. Some efforts focused on the characteristics of the code, such as polyhedral compilers (e.g. Pluto, PPCG, etc.) while others …

Osteogenic Potential Of Poly (L-Lactic Acid) Scaffolds Prepared By Thermally Controlled Methods On Human Adipose Derived Stem Cells, Harish Chinnasami Shanmugam

LSU Doctoral Dissertations

Thermally Induced Phase Separation (TIPS) method was used to make porous three-dimensional PLLA scaffolds. The effect of imposed thermal profile during freezing of the PLLA in dioxane solution on the scaffold was characterized by their micro-structure, porosity (%), pore-sizes distribution and mechanical strength. The porosity (%) decreased considerably with increasing concentrations of PLLA in the solution, while a decreasing trend was observed with increasing cooling rates. The mechanical strength increases with increase in PLLA concentration and also with increase in the cooling rate for both types of solvents. Therefore, mechanical strength was increased by higher cooling rates while the porosity …

Microcavity Enhanced Beaming And Magneto-Optical Switching Of Light, Ali Haddadpour

LSU Doctoral Dissertations

In this dissertation, we show numerically that a compact structure, consisting of multiple optical microcavities at both the entrance and exit sides of a subwavelength plasmonic slit, can lead to greatly enhanced directional transmission through the slit. The microcavities increase the resonant enhancement of the emission in the normal direction and/or the coupling between free space waves and the slit mode. An optimized structure with two microcavities on both the entrance and exit sides of the slit leads to ~ 16 times larger transmission cross section per unit angle in the normal direction compared to the optimized reference slit without …

The Formation Of Polycyclic Aromatic Hydrocarbons From The Pyrolysis Of Model 1-Alkene Fuels, Eva Christine Caspary

LSU Doctoral Dissertations

To understand the role of 1-alkenes and allylic radicals in the reaction pathways leading to the formation and growth of polycyclic aromatic hydrocarbons (PAH), pyrolysis experiments have been performed with three 1-alkene fuels—propylene (CH₂=CH–CH₃), 1-butene (CH₂=CH–CH₂–CH₃), and 1-pentene (CH₂=CH–CH₂–CH₂–CH₃)—at temperatures of 600 – 1000 °C and a fixed residence time of 0.31 s. The experiments are carried out in an isothermal laminar-flow quartz-tube reactor. Analyses of the pyrolysis products by gas-chromatographic and high-pressure liquid-chromatographic techniques reveal that the three fuels differ in: 1) their conversion behavior, 2) the relative amounts of the major C₂ – C₄ species produced, and 3) …

Modeling Of Size Effects In Metallic Samples Of Confined Volumes, Mohammadreza Yaghoobi

LSU Doctoral Dissertations

In material science, size effects is described as the variation of material properties as the sample size changes. In this dissertation, the size dependency of the material strength is addressed as size effects. The size effects underlying mechanisms depend on the nature of the considered material. In the case of crystalline metals, size effects in crystalline metals are governed by the dislocations, as the primary deformation mechanism, and their interactions with one another and other defects such as grain boundaries. In this dissertation, the size and strain rate effects of fcc metallic samples of confined volumes are investigated during the …

Computational Studies On Fluid And Particle Dynamics, Chenguang Zhang

LSU Doctoral Dissertations

This dissertation is divided into two parts. The first part includes chapter 2 to 4, which focus on development and application of numerical algorithm on particle and fluid simulation. Starting with a pure granular system in a driven cavity setup (Chapter 2), we move on to the immersed boundary simulation of fluid solid interaction (Chapter 3). This part ends with a coupled immersed boundary-discrete particle implementation. The second part includes Chapter 5 and Appendix A, each deals with an independent problem and focuses more on the theoretical aspects. Chapter 5 deals with a classic fluid dynamics problem of thermal wave …

Characterization Of Dehalogenimonas Strains From A Louisiana Superfund Site That Reductively Dehalogenate Polychlorinated Alkanes, Trent Anthony Key

LSU Doctoral Dissertations

The research described in this dissertation was aimed at expanding understanding of the diversity and functional roles of microorganisms able to anaerobically transform chlorinated compounds. During the course of the research, a novel strictly anaerobic bacterial isolate originating from chlorinated solvent contaminated groundwater at a Superfund Site in south Louisiana (USA) was characterized. Phylogenetic analysis based on 16S rRNA gene sequencing placed the newly isolated strain, designated as NSZ-14 T, within the genus Dehalogenimonas but within a separate lineage from previously described species. Like previously described species within the genus Dehalogenimonas (i.e., D. lykanthroporepellens and D. alkenigignens), strain NSZ-14T was …

Tribological And Dynamical Study Of An Automotive Transmission System, Meng Li

LSU Doctoral Dissertations

The transmission system is critical for automotive and heavy duty equipment due to its prominent role in the powertrain system, which is often challenged with degraded torque capacity and harsh dynamic response. Simulation-guided design can provide appropriate guidelines to resolve these problems with virtual analyses. In current study, the tribological and dynamical study of an automatic transmission is performed at two levels: a wet clutch and powertrain. In this dissertation, tribological study is performed for a wet clutch based on the thermohydrodynamic (THD) analysis that takes the following factors into account. • The groove effect (depth, area, and pattern) is …

Healing Mechanism Investigation Of Self-Healing Concrete By Microencapsulated Calcium Nitrate, Gabriel Andres Arce Amador

LSU Doctoral Dissertations

Durability of reinforced concrete structures depends highly on the integrity of the concrete which protects the structure from the environment. However, concrete is a brittle material and as such it is prone to cracking which allows for detrimental agents to penetrate the structure and produce early deterioration. Embedding microcapsules with chemical healing agents in concrete materials for self-healing applications as well as implementing SMAs as reinforcement of concrete structures for self-closing of cracks are both state-of-the-art techniques with enormous potential for enhancement of concrete infrastructure durability. In this work, both techniques are combined as an alternative for superior self-healing of …