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Articles 1591 - 1620 of 2820
Full-Text Articles in Engineering
Parametric Optimization Of A Single-Tracked Vehicle, Darrick Jason Berner
Parametric Optimization Of A Single-Tracked Vehicle, Darrick Jason Berner
LSU Master's Theses
ABSTRACT The purpose of a suspension system for a vehicle is to contribute to the handling and assist in isolating the occupants from vibrations due to road irregularities. Generally, these primary functions are often at odds so the goal is to design a suspension system that finds the appropriate compromise. The focus of this thesis is to develop a two degree of freedom model and use parametric analysis to demonstrate an optimization technique by varying several geometric characteristics on a single-track vehicle. Furthermore, a dynamic vibration absorber will be added to the model to demonstrate its effect on the system. …
Closed Form Solutions To The Optimality Equation Of Minimal Norm Actuation, Jorge Antonio Guerra
Closed Form Solutions To The Optimality Equation Of Minimal Norm Actuation, Jorge Antonio Guerra
LSU Master's Theses
This research focused on the problem of minimal norm actuation in the context of partial natural frequency or pole assignment applied to undamped vibrating systems by state feedback control. The result of the research was the closed form solutions for the minimal norm control input and gain vectors. These closed form solutions should took open loop eigenpairs and the desired frequencies of the controlled system and outputted the optimal controller parameters. This optimization technique ensures that the system’s dynamics will be effectively controlled while keeping the controller effort minimal. The controller must then be able to shift only the desired …
Effects Of Partial Confinement And Local Heating On Healing Efficiencies Of Self-Healing Particulate Composites, Jonah Champagne
Effects Of Partial Confinement And Local Heating On Healing Efficiencies Of Self-Healing Particulate Composites, Jonah Champagne
LSU Master's Theses
Shape memory polymers are smart materials that can be trained to hold a temporary shape through programming and regain their original shape upon heating. Since there discovery in the 1960s, much research has been devoted to the study of these polymers. Of particular interest in recent years is the study of self-healing shape memory polymers. In a previous study, it has been shown that in order for efficient healing to take place in self-healing shape memory polymers, confinement during healing is essential. Moreover, a two-step close-then-heal (CTH) approach to healing was suggested. It was shown that use of this CTH …
Dynamic Modeling Of Channel Formation During Fluid Injection Into Unconsolidated Sands, Sayamik Ameen
Dynamic Modeling Of Channel Formation During Fluid Injection Into Unconsolidated Sands, Sayamik Ameen
LSU Master's Theses
Water injection is widely used for sweeping hydrocarbons in waterflooding operations, and also for maintaining reservoir pressure or disposing waste water. Injection at a high rate is required to maintain the economy of waterflooding projects; however, loss of injectivity is a quite common problem in unconsolidated sand formations like deep water Gulf of Mexico. Well intervention operations, hurricanes, and other issues require frequent shut-downs during the life of offshore wells; in order to minimize deteriorating effect of these shutdowns on wellbore injectivity more accurate modeling of the injection process is needed. Injection of water into a saturated, granular, porous medium …
Aggregation Of Uncontrolled Fluids During Catastrophic System Failures In Offshore Environments, James Thomas Stiernberg
Aggregation Of Uncontrolled Fluids During Catastrophic System Failures In Offshore Environments, James Thomas Stiernberg
LSU Master's Theses
Safety culture relating to offshore operations has shifted since the Deepwater Horizon blowout and resulting oil spill. This incident has prompted the research of high volume spills during all stages of hydrocarbon exploration and production. This study particularly covers the interactions of wells and offshore networks as they pertain to situations where a release of reservoir fluids to the environment is occurring. Primary concerns of this investigation are stream confluences, leak modeling, and fluid behavior; the first two will be handled with various numerical software packages (OLGA®, CFD, and nodal analyses) while the later will require more rigorous treatment and …
Experimental Fragility Analysis Of Aluminum Storm Panels Subject To Windborne Debris, Taylor C. Alphonso
Experimental Fragility Analysis Of Aluminum Storm Panels Subject To Windborne Debris, Taylor C. Alphonso
LSU Master's Theses
The research presented in this thesis focused on the derivation of experimental fragility curves for windborne debris (WBD) impact risk assessment of building envelope components (BECs) with ductile behavior (in particular, aluminum storm panels) within the performance-based hurricane engineering (PBHE) framework. Using a pneumatic wind cannon, rod-type WBDs were fired at aluminum storm panels to represent real-life WBD impact hazard. The experimental data from testing were used to derive the probability of failure relative to specific damage measures (DMs) versus its corresponding interaction parameter (IP). These experimentally derived probabilities were compared with results that are available in the literature and …
Effect Of Surface Roughness On The Efficiency Of Self-Healing Polymers, Ifeanyi Janarus Okoro
Effect Of Surface Roughness On The Efficiency Of Self-Healing Polymers, Ifeanyi Janarus Okoro
LSU Master's Theses
A shape memory polymer (SMP) is a smart material capable of maintaining two distinct shapes depending on its temperature. A SMP is soft at temperatures above its glass transition temperature but hard below it. When copolyester thermoplastic additives are dispersed in a SMP, it becomes a SMP-based particulate composite capable of self-healing at both the molecular level and the structural level. This makes it very desirable for industrial applications. Upon damage to the composite, the surfaces at the damage interface have to come into contact for efficient healing; the shape memory effect, coupled with a confined recovery (healing) process, ensures …
Yield Detection For Non-Destructive Testing Using Ultrasonic Signal Processing, Bharath Murali Thekkedath
Yield Detection For Non-Destructive Testing Using Ultrasonic Signal Processing, Bharath Murali Thekkedath
LSU Master's Theses
Structural health monitoring (SHM) is a very important field for many engineering disciplines. SHM deals with the monitoring of material structures periodically for assessing the lifetimes of the structures. There are various techniques for SHM. Non-destructive testing (NDT) is one of the most popular SHM tools to monitor structures. It demonstrates the indispensable advantage of providing structural health assessment without the need of intrusion. In this thesis, a new NDT tool for yield detection using ultrasonic signal processing is investigated. In this work, for the study of yield detection, steel specimen samples have been acquired, which were obtained from the …
Discrete Phase Simulations Of Drilled Cuttings Transport Process In Highly Deviated Wells, Doguhan Yilmaz
Discrete Phase Simulations Of Drilled Cuttings Transport Process In Highly Deviated Wells, Doguhan Yilmaz
LSU Master's Theses
Transporting drilled cuttings from the bottomhole to the surface becomes more difficult and problematic in highly deviated wells than in vertical wells. Cuttings tend to settle down on the low side of the annulus typically in the form of a bed which can cause further problems. The height of this bed depends on many parameters such as annular domain geometry, drilling fluid density and rheology, annular flow rate, drill pipe rotation speed, cuttings size, shape, and their density. Prediction of the stationary cuttings bed height with respect to these aforementioned parameters is thus necessary to optimize the range of the …
Coastal Plants For Biofuel Production And Coastal Preservation, Chester Charles Malveaux
Coastal Plants For Biofuel Production And Coastal Preservation, Chester Charles Malveaux
LSU Master's Theses
ABSTRACT Sustainable and renewable biofuels as well as coastal preservation are important to the State of Louisiana which is losing its coastline at the rate of up to 100 square kilometers per year. This has important implications for other coastal areas worldwide. By managing water hyacinth in canals and lakes in coastal Louisiana the biomass of this fast growing aquatic plant can reduce coastal erosion by absorbing wave energy, and remediate waste water through bioabsorption of contaminants, while also providing a source of biofuel. This research has shown that coastal vegetation can play a part in lessening the impact of …
Catalytic Conversion Of Biomass Derived Syngas To Liquid Fuels Using Fischer-Tropsch Synthesis, Pratibha Sharma
Catalytic Conversion Of Biomass Derived Syngas To Liquid Fuels Using Fischer-Tropsch Synthesis, Pratibha Sharma
LSU Master's Theses
Biomass gasification and subsequent conversion to liquid hydrocarbons using Fischer-Tropsch synthesis is a promising source of energy in today’s scenario when the focus has shifted from conventional fuels to alternate sources of energy. Biomass derived syngas is different from other sources of syngas such as steam reforming of methane followed by water gas shift, in terms of H2/CO ratio. Biomass syngas is usually hydrogen deficient and contains various impurities which need to be removed prior to Fischer-Tropsch Synthesis. Syngas derived from biomass also differs significantly with the different sources of biomass, gasification process and the cleanup conditions it is subjected …
Characterization And Verification Of A Closed Loop Wind Tunnel With A Linear Cascade And Upstream Wake Generator, Christopher Foreman
Characterization And Verification Of A Closed Loop Wind Tunnel With A Linear Cascade And Upstream Wake Generator, Christopher Foreman
LSU Master's Theses
A closed loop wind tunnel designed to study film cooling was completed in May 2011 along with a removable wake generating device. The test section featured a three blade, four passage linear cascade utilizing the Air Force Office of Scientific Research L1A low pressure turbine blade. The wake generator is unique because its blades are flat plates with round leading and trailing edges instead of circular rods. In this report, the test section of the wind tunnel is characterized and validated through velocity and pressure measurements in the test section. Hot-wire surveys were used to characterize the velocity and turbulence …
Learning And Identification Of Wireless Network Internode Dynamics Using Software Defined Radio, Benjamin Elliott Carroll
Learning And Identification Of Wireless Network Internode Dynamics Using Software Defined Radio, Benjamin Elliott Carroll
LSU Master's Theses
The recently developed paradigm of cognitive radio wireless devices has been developed with the goal of achieving more customizable and efficient spectrum utilization of commonly used wireless frequency bands. The primary focus of such spectrum utilization approaches has been to discern occupancies and vacancies over portions of the wireless spectrum without necessarily identifying how specific radio frequency (RF) devices contribute to the temporal dynamics of these occupancy patterns within the spectrum. The aim of this thesis is to utilize a hidden semi-Markov model (HSMM) statistical analysis to infer the individual occupancy patterns of specific users from wireless RF observation traces. …
Investigation Of Best Practices For Maintenance Of Concrete Bridge Railings, Angel Luis Lence
Investigation Of Best Practices For Maintenance Of Concrete Bridge Railings, Angel Luis Lence
LSU Master's Theses
Biodeterioration on concrete surfaces of vertical elements of bridges represents a serious challenge to the highway infrastructure in Louisiana. This investigation aims to document the causes of biodeterioration of concrete surfaces and to document current conventional and state-of-the-art practices implemented to prevent and clean biofilm. A comprehensive literature review of previous research has been carried out in order to determine the cause and mechanisms of the biodeterioration as well as to identify current methods that state DOTs have implemented in order to maintain their bridges and allow them to function in optimal structural and performance conditions. A survey was developed …
Blind Ldpc Encoder Identification, Tian Xia
Blind Ldpc Encoder Identification, Tian Xia
LSU Master's Theses
Nowadays, adaptive modulation and coding (AMC) techniques can facilitate flexible strategies subject to dynamic channel quality. The AMC transceivers select the most suitable coding and modulation mechanisms subject to the acquired channel information. Meanwhile, a control channel or a preamble is usually required to synchronously coordinate such changes between transmitters and receivers. On the other hand, low-density parity-check (LDPC) codes become more and more popular in recent years due to their promising capacity-approaching property. The broad range of variations in code rates and codeword lengths for LDPC codes makes them ideal candidates for future AMC transceivers. The blind encoder identification …
A Dynamic Feedback-Control Toll Pricing Methodology : A Case Study On Interstate 95 Manged Lanes, Danhong Cheng
A Dynamic Feedback-Control Toll Pricing Methodology : A Case Study On Interstate 95 Manged Lanes, Danhong Cheng
LSU Master's Theses
Recently, congestion pricing emerged as a cost-effective and efficient strategy to mitigate the congestion problem on freeways. This study develops a feedback-control based dynamic toll approach to formulate and solve for optimal tolls. The study compares the performance of the proposed methodology to that of the current strategy deployed on Interstate 95 express lanes. Two objectives are studied: one is to maximize the toll revenue while maintaining a minimum level of service on the managed lanes and the other is to maximize both revenue and throughput on the managed lanes while keeping a minimum level of service. The impact of …
Controversy Trend Detection In Social Media, Rajshekhar Vishwanath Chimmalgi
Controversy Trend Detection In Social Media, Rajshekhar Vishwanath Chimmalgi
LSU Master's Theses
In this research, we focus on the early prediction of whether topics are likely to generate significant controversy (in the form of social media such as comments, blogs, etc.). Controversy trend detection is important to companies, governments, national security agencies, and marketing groups because it can be used to identify which issues the public is having problems with and develop strategies to remedy them. For example, companies can monitor their press release to find out how the public is reacting and to decide if any additional public relations action is required, social media moderators can moderate discussions if the discussions …
Time-Variant Performance Assessment And Improvement Of Existing Bridges, Miao Xia
Time-Variant Performance Assessment And Improvement Of Existing Bridges, Miao Xia
LSU Doctoral Dissertations
The serviceability and safety of buildings and bridges are expected to be maintained within a reasonable safety level throughout their lifetimes. However, the increase of the applied loads and degradation of structural performances reduce the safety of these structures over time. Therefore, the performance assessment of existing bridges with reliability theories is a worldwide problem in civil infrastructure systems. Theoretically, the bridge reliability, usually expressed by a reliability index, is quantified by comparing the structural capacity (R) with the load effects (Q), using the predefined limit state functions. A limit state function is a mathematical description of a boundary between …
Automated Semantic Content Extraction From Images, Mahdi Arab Khazaeli
Automated Semantic Content Extraction From Images, Mahdi Arab Khazaeli
LSU Doctoral Dissertations
In this study, an automatic semantic segmentation and object recognition methodology is implemented which bridges the semantic gap between low level features of image content and high level conceptual meaning. Semantically understanding an image is essential in modeling autonomous robots, targeting customers in marketing or reverse engineering of building information modeling in the construction industry. To achieve an understanding of a room from a single image we proposed a new object recognition framework which has four major components: segmentation, scene detection, conceptual cueing and object recognition. The new segmentation methodology developed in this research extends Felzenswalb's cost function to include …
Modeling And Simulation Of Surface Profile Forming Process Of Microlenses And Their Application In Optical Interconnection Devices, Zhengyu Miao
LSU Doctoral Dissertations
Free space micro-optical systems require to integrate microlens array, micromirrors, optical waveguides, beam splitter, etc. on a single substrate. Out-of-plane microlens array fabricated by direct lithography provides pre-alignment during mask fabrication stage and has the advantage of mass manufacturing at low cost. However, this technology requires precise control of the surface profile of microlenses, which is a major technical challenge. The quality control of the surface profile of microlenses limits their applications. In this dissertation, the surface forming process of the out-of-plane microlenses in UV-lithography fabrication was modeled and simulated using a simplified cellular automata model. The microlens array was …
Multi-Scale Modeling Of Inertial Flows Through Propped Fractures, Ali Takbiri Borujeni
Multi-Scale Modeling Of Inertial Flows Through Propped Fractures, Ali Takbiri Borujeni
LSU Doctoral Dissertations
Non-Darcy flows are expected to be ubiquitous in near wellbore regions, completions, and in hydraulic fractures of high productivity gas wells. Further, the prevailing dynamic effective stress in the near wellbore region is expected to be an influencing factor for the completion conductivity and non-Darcy flow behavior in it. In other words, the properties (fracture permeability and β-factor) can vary with the time and location in the reservoir (especially in regions close to the wellbore). Using constant values based on empirical correlations for reservoirs/completions properties can lead to erroneous cumulative productivity predictions. With the recent advances in the imaging technology, …
Bioremediation Of Chlorinated Ethanes And Ethenes In Vertical Flow Engineered Wetland Systems, Christopher Akudo
Bioremediation Of Chlorinated Ethanes And Ethenes In Vertical Flow Engineered Wetland Systems, Christopher Akudo
LSU Doctoral Dissertations
Sustainable treatment of chlorinated ethanes and ethenes contaminated groundwater using vertical flow engineered wetland systems were investigated in microcosm and column studies. Experiments on environmental and biogeochemical factors that affect system performance were conducted, and a numerical model involving advection, sorption, and sequential biodegradation was developed to describe the fate and transport of the contaminants of concern in the treatment wetland bed. 1,1-dichloroethane (1,1-DCA) and cis-1,2-dichloroethene (cis-1,2-DCE) were used as the chemicals of interest. The presence of cis-1,2-DCE inhibited dechlorination of 1,1-DCA but cis-1,2-DCE dechlorination was not affected by the presence of 1,1-DCA. Simulation runs showed that the treatment bed …
Nanoindentation Characterization Of Clay Minerals And Clay-Based Hybrid Bio-Geomaterials, Rohit Raj Pant
Nanoindentation Characterization Of Clay Minerals And Clay-Based Hybrid Bio-Geomaterials, Rohit Raj Pant
LSU Doctoral Dissertations
Layered hydrous aluminosilicates are key constituent minerals in rocks, soils, and other parts of the Earth crust. Understanding mechanical properties of these aluminosilicates is crucial for seismic study, stability of parent rocks and geomaterials, and for geophysical subsurface exploration. Recently, growing prospects of clay based nanocomposites have renewed further interest in understanding the fundamental elastic and plastic properties of hydrous aluminosilicates. Their distinct, nanoscale layered crystal structure is known to result in anisotropic responses to loading, however, owing to their tiny sizes; it is a significant challenge to determine the anisotropic properties. There is a little data available in the …
Induction Motors With Rotor Helical Motion, Ebrahim Amiri
Induction Motors With Rotor Helical Motion, Ebrahim Amiri
LSU Doctoral Dissertations
Performance analysis of the twin-armature rotary-linear induction motor, a type of motor with two degrees of mechanical freedom, is the subject of this dissertation. The stator consists of a rotary armature and linear armature placed aside one another. Both armatures have a common rotor which can be either solid or cage rotor. The rotor can move rotary, linearly or with helical motion. The linear motion generates dynamic end effect on both linear and rotary armature. Modeling such an effect in rotary armature is a significant challenge as it requires a solution considering motion with two degrees of mechanical freedom. In …
The Investigation Of Valve Operators' Torque Production Capabilities And Optimal Handwheel Height, Angle, And Opening Technique, Saif K. Al-Qaisi
The Investigation Of Valve Operators' Torque Production Capabilities And Optimal Handwheel Height, Angle, And Opening Technique, Saif K. Al-Qaisi
LSU Doctoral Dissertations
This research consists of two projects concerned with handwheel-valve operations. The objectives of poject-1 were to: (1) introduce an ergonomically-modified valve-wrench and compare it to conventional valve-opening methods, in terms of efficiency (time to open valve), perceived physical exertion (Borg-scale), and muscle loading of shoulder and trunk muscles; and (2) determine whether the torque setting (15 Nm and 30 Nm) of the valve affects the preferred valve-opening method. Four methods were evaluated, including using bare hands (BH), conventional wrench-restricted (CW-R, assumes presence of obstructions), conventional wrench-unrestricted (CW-U, assumes no obstructions), and modified wrench (MW). Electromyography (EMG) activities were measured from …
Molecular Dynamics Of Ionic Liquids In Nanoporous Electrodes, Nav Nidhi Rajput
Molecular Dynamics Of Ionic Liquids In Nanoporous Electrodes, Nav Nidhi Rajput
LSU Doctoral Dissertations
Molecular dynamics simulations were performed to investigate structural, dynamical and electrical properties of ionic liquids (ILs) confined inside different nanoporous materials. These systems have potential uses in environmental and energy applications. The main goal is to understand how these IL properties are affected by a) characteristics of nanoporous materials such as chemical nature of the pore walls (e.g., carbon, titania), pore size and pore morphology, and b) characteristics of electrolyte, such as amount of IL inside the pores (pore loading) and concentration of organic solvent, in the case of mixtures of ILs with organic solvents. The results obtained in this …
Optimal Consignment Stocking Policies For A Supply Chain Under Different System Constraints, Hui Zhi Yi
Optimal Consignment Stocking Policies For A Supply Chain Under Different System Constraints, Hui Zhi Yi
LSU Doctoral Dissertations
The research aims are to enable the decision maker of an integrated vendor-buyer system under Consignment Stock (CS) policy to make the optimal/sub-optimal production/replenishment decisions when some general and realistic critical factors are considered. In the system, the vendor produces one product at a finite rate and ships the outputs by a number of equal-sized lots within a production cycle. Under a long-term CS agreement, the vendor maintains a certain inventory level at the buyer’s warehouse, and the buyer compensates the vendor only for the consumed products. The holding cost consists of a storage component and a financial component. Moreover, …
Emergence Of Delamination Fractures Around Casing And Its Stability, Wei Wang
Emergence Of Delamination Fractures Around Casing And Its Stability, Wei Wang
LSU Doctoral Dissertations
The cement sheath failures and nearby wellbore failures may lead to upward flow of drilling fluid or formation fluid, which may have significantly adverse consequences like loss of reserve and environmental hazards. In order to maintain wellbore integrity in the long term, it is expedient to examine the causes of failures around the wellbore and propose suitable numerical models to predict annulus cracks around the casing. The complex failure behavior of cement/rock interfaces observed in the laboratory experiments does not look like the behavior of linear or simple nonlinear mechanical interfaces. Cohesive zone method (CZM) with BK-form bilinear traction separation …
Assessing Levels Of Reliability For Design Criteria For Hurricane And Storm Damage Risk Reduction Structures, Christopher Leslie Dunn
Assessing Levels Of Reliability For Design Criteria For Hurricane And Storm Damage Risk Reduction Structures, Christopher Leslie Dunn
LSU Doctoral Dissertations
In the wake of Hurricane Katrina, the U.S. Army Corps of Engineers (USACE) updated design methodologies and required factors of safety for hurricane and storm damage risk reduction system (HSDRRS) structures to incorporate lessons-learned from the system performance during Katrina and results of state-of-the-art research in storm surge modeling and foundation behavior. However, the criteria (USACE 2008) were not calibrated to a target reliability, which creates the need to understand the reliability provided by designs using those criteria, especially for pile-founded structures subject to global instability. This dissertation presents a methodology for quantifying the reliability of pile-founded structures that can …
A Study On The Cleaning And Modification Of Metal Surfaces By Direct Current Cathodic Electrolytic Plasma Process, Jiandong Liang
A Study On The Cleaning And Modification Of Metal Surfaces By Direct Current Cathodic Electrolytic Plasma Process, Jiandong Liang
LSU Doctoral Dissertations
The processes of surface treatments or surface modifications, more formally known as surface engineering, tailor the surfaces of engineering materials. The treatments are usually intended to change physical properties such as thermal or electrical conductivity, modify the surface dimensions, i.e. roughness, etc. A novel surface treatment method, Electrolytic Plasma Process (EPP), was developed for coating purposes, in its early developmental stage. In this work, the major effort is to avoid using any environmental hazardous chemical (coatings) and to extend such its application to some new fields. The general response of the substrate material under electrolytic plasma process was summarized including …