Engineering Commons^™

Cost And Performance Modeling Of The Mu-Decoder, Raghavendra Kongari

LSU Master's Theses

In this thesis we study the implementation details of the MU-Decoders, a recently proposed hardware module that has been theoretically shown to be superior to other methods for generating subsets of large sets. Our study confirms this advantage. Specifically, we compare the performance of implementations of the LUT-Decoder (the most common configurable decoder) to the MU-Decoder. We show that for while the LUT-Decoder is slightly better than the MU-Decoder for arbitrary (and artificial) inputs, for a large class of inputs called totally ordered subsets, that have practical significance, the MU-Decoder is vastly superior in area to the LUT-Decoder. In terms …

Pavement Structural Evaluation Using The Rolling Wheel Deflectometer, Ahmed Moustafa Abdel-Khalek

LSU Master's Theses

The Rolling Wheel Deflectometer (RWD) offers the benefit to measure pavement deflection without causing any traffic interruption or compromising safety along the tested road segments. This study describes a detailed field evaluation of the RWD system in Louisiana in which 16 different test sites representing a wide array of pavement conditions were tested. Measurements were used to assess the repeatability of RWD measurements, to examine the effect of truck speeds, and to study the relationship between RWD and FWD deflection measurements and pavement conditions. Based on the results of the experimental program, it was determined that the repeatability of RWD …

Communication-Constrained Feedback Stability And Multi-Agent System Consensusability In Networked Control Systems, Laurentiu Dan Marinovici

LSU Doctoral Dissertations

With the advances in wireless communication, the topic of Networked Control Systems (NCSs) has become an interesting research subject. Moreover, the advantages they offer convinced companies to implement and use data networks for remote industrial control and process automation. Data networks prove to be very efficient for controlling distributed systems, which would otherwise require complex wiring connections on large or inaccessible areas. In addition, they are easier to maintain and more cost efficient. Unfortunately, stability and performance control is always going to be affected by network and communication issues, such as band-limited channels, quantization errors, sampling, delays, packet dropouts or …

Small Footprint High Flow Rate Microdevice For Rare Target Cell Capture, Taehyun Park

LSU Doctoral Dissertations

A novel high flow rate cell capture design was introduced to overcome the limitations of the current technologies or methods for rare target cell capture. Even though the rare target cell capture using BioMEMS technology has great potential for cancer diagnosis, previous rare cell capture research could not overcome the limitations of low flow rate or low recovery rate. Rare cell research requires precise sample preparation for accurate results. A new method of preparation for a single or a precise number of target cell was introduced. Current sample preparation methods which are not suitable for rare cell research, such as …

Anti-Microbial Self-Assembling "Click" Monolayers Utilizing Silver Nanoparticles For Indwelling Medical Devices, Emily Ann Hodges

LSU Master's Theses

The objective of this study was to synthesize and characterize antimicrobial, silver nanoparticles based self-assembling monolayer coatings, for use on chronic indwelling medical devices. The coatings are comprised of novel biomass mediated silver nano particles (SNP) that are biocompatible, highly concentrated, highly pure, cost-effective, polydispersed and compatible for use with existing chronic indwelling medical devices. The HPC SNPs were functionalized with an azide functional group and covalently bound to titanium substrates via ¨Dclick¡¬ chemistry.

Computational Modeling Of Geogrid Reinforced Soil Foundation And Geogrid Reinforced Base In Flexible Pavement, Jie Gu

LSU Doctoral Dissertations

The objectives of this study are to investigate and evaluate the benefits of inclusion of geogrids in two types of geosynthetic reinforced soil/aggregate structures—e.g. reinforced soil foundations (RSF) and reinforced base aggregate in flexible pavements, thus shedding the light on the design of these reinforced structures. Two different finite element models were developed using ABAQUS software. The first model was used to investigate the bearing capacity and settlement of RSF and to perform parametric study on the effect of different design parameters on the performance of RSF. The second model was used to analyze the performance of geogrid reinforced bases …

Dry Reforming Of Methane On Rhodium And Nickel Substituted Pyrochlore Catalysts, Sarthak Gaur

LSU Master's Theses

Dry reforming of methane (DRM) has been widely investigated, with most studies showing rapid deactivation due to carbon deposition. This suggests a need to develop catalysts that limit carbon formation while avoiding structural changes at the elevated temperatures typical of this reaction. Here, we report CO2 reforming of methane on four pyrochlore catalysts. First, Rh was partially substituted for Zr in lanthanum zirconate (La2Zr2O7) to give La2Zr2-xRhxO7.5 (LRZ, x=0.112, 2 wt% Rh) pyrochlore. A second pyrochlore catalyst was synthesized in which Ca was further substituted into the La-site to give La1.95Ca0.05Zr2-xRhxO7 (LCRZ, x=0.055, 1 wt% Rh). A third catalyst was …

Secure Distributed Detection In Bandwidth-Constrained Wireless Sensor Networks, Reza Soosahabi

LSU Master's Theses

Utilizing wireless sensor network (WSN) is a novel idea in a variety of applications. However, the limited resources allocated to the sensor nodes make the design of WSNs a challenging problem. We consider the problem of hypothesis testing in a bandwidth-constrained, low-power wireless sensor network operating over insecure links. Sensors quantize their observations and transmit their decisions to an intended (ally) fusion center (AFC) which combines the received messages to detect the state of an unknown hypothesis.

In many applications the sensor messages are vulnerable to unauthorized eavesdropping. The scarce bandwidth and processing power for the sensors rule out the …

Phase Noise In Cmos Phase-Locked Loop Circuits, Yang Liu

LSU Doctoral Dissertations

Phase-locked loops (PLLs) have been widely used in mixed-signal integrated circuits. With the continuously increasing demand of market for high speed, low noise devices, PLLs are playing a more important role in communications. In this dissertation, phase noise and jitter performances are investigated in different types of PLL designs. Hot carrier and negative bias temperature instability effects are analyzed from simulations and experiments. Phase noise of a CMOS phase-locked loop as a frequency synthesizer circuit is modeled from the superposition of noises from its building blocks: voltage-controlled oscillator, frequency divider, phase-frequency detector, loop filter and auxiliary input reference clock. A …

Replenishment Policies For A Tree-Type Three Echelon Supply Chain System, Ratkrit Rochanaluk

LSU Master's Theses

One of the common goals which most companies have is to maximize profits. There are two way to increase profit: increasing revenue or reducing cost. Lacking of ability to keep the cost down could potentially drive the companies out of the business. In recent years, many researchers have been paying more attention on improving supply chain system due to high potential of creating cost savings. The supply chain network considered in this research is a tree-type, three-echelon single producer, multiple distributors, and multiple retailers system. The goal of this research is to develop a replenishment policy which satisfies customers’ demand …

Silicon Nanowire Anode For Lithium-Ion Batteries: Fabrication, Characterization And Solid Electrolyte Interphase, Wanli Xu

LSU Doctoral Dissertations

Depletion of fossil fuels and concerns over CO2 emission have driven the development of electric vehicles (EVs) with high-energy efficiencies and low emissions. Lithium-ion rechargeable batteries, compared to lead acid, nickel cadmium, nickel metal hydroxide, and other popular rechargeable batteries, are considered as the most promising candidates for EVs for their high operating voltage and high energy density. Silicon nanowires are considered as lithium-ion battery anodes for their ultra high capacity at 4200 mAh·g-1 (10× higher than conventional graphite anode), as well as stress accommodation for reversible lithiation and delithiation. Silicon nanowires were fabricated via metal assisted electroless etching, and …

Alternative Pretreatment Of Sorghum Bagasse For Bio-Ethanol Production, Cong Chen

LSU Master's Theses

The majority of the world’s energy needs are currently met through the use of fossil fuels. The possible depletion of fossil fuel resources and environmental concerns has prompted the search for alternative renewable and environmentally friendly energy resources. The goal of this research was to develop a microwave-assisted dilute ammonia pretreatment technology for the conversion of sweet sorghum into ethanol. Conversion of biomass into ethanol requires a pretreatment step to open up the structure and decouple the cellulose, and hemicellulose and lignin in the biomass. In the first study, sorghum bagasse was pretreated with 28% ammonium hydroxide, and water at …

Fabrication And Property Study Of Plasma Sprayed Alumina Coatings And Magnetron Sputtered Multilayers, Ranran Liu

LSU Doctoral Dissertations

In this study, air or atmospheric plasma spraying (APS), one of thermal spraying processes, was used to produce alumina coatings and single splats. Nanoindentation technique was used to measure the mechanical properties, such as hardness and elastic modulus, of APS alumina coatings and single splats. The detailed procedures to calculate elastic modulus and hardness, and testing parameters for nanoindentation have been provided. This study revealed that the phase combination of α-Al2O3 and γ-Al2O3 played an important role in the scattering distribution of nanoindentation results on APS alumina coatings. In addition, nanoindentation technique was used to predict the phase information of …

Integrating Multiple Clusters For Compute-Intensive Applications, Zhifeng Yun

LSU Doctoral Dissertations

Multicluster grids provide one promising solution to satisfying the growing computational demands of compute-intensive applications. However, it is challenging to seamlessly integrate all participating clusters in different domains into a single virtual computational platform. In order to fully utilize the capabilities of multicluster grids, computer scientists need to deal with the issue of joining together participating autonomic systems practically and efficiently to execute grid-enabled applications. Driven by several compute-intensive applications, this theses develops a multicluster grid management toolkit called Pelecanus to bridge the gap between user's needs and the system's heterogeneity. Application scientists will be able to conduct very large-scale …

Development And Validation Of Biomechanical Models To Quantify Horse Back Forces At The Walk In Three Horse Breeds, Laxmi Raghunandana Kaidapuram

LSU Master's Theses

Therapeutic horseback riding is a common component of physical therapy programs. Quantification of the horse back forces will provide vital information to match therapeutic riders with equine partners. To meet this medical need, a model to quantify the horse back forces from ground reaction forces was developed to test the hypothesis that the forces transferred to a static weight on the horse’s back can be predicted given horse breed and weight. Simultaneous, real time kinetic, kinematic, and back force data on a static weight were collected from 7 adult horses: 3 thoroughbreds, 3 quarter horses, and 1 paso fino. An …

Reducing Complexity Of Processor Front Ends With Static Analysis And Selective Preloading, Santhosh Verma

LSU Doctoral Dissertations

General purpose processors were once designed with the major goal of maximizing performance. As power consumption has grown, with the advent of multi-core processors and the rising importance of embedded and mobile devices, the importance of designing efficient and low cost architectures has increased. This dissertation focuses on reducing the complexity of the front end of the processor, mainly branch predictors. Branch predictors have also been designed with a focus on improving prediction accuracy so that performance is maximized. To accomplish this, the predictors proposed in the literature and used in real systems have become increasingly complex and larger, a …

Server Assignment In Mirrored Server Environments, Shawn Farlow

LSU Master's Theses

Massively multiplayer online games (MMOGs) may use peer-to-peer, client-server, or mirrored-server environments. Since there exist multiple server options in mirrored server environments, a problem arises when deciding to which server each player should connect. We propose three distinct algorithms that assign players within Quality of Service (QoS) as each player joins and leaves, taking into consideration whether a player already in QoS can be moved to place a newly joining player in QoS without sacrificing QoS for the moved player. Our results show that for certain numbers of servers and values of QoS, our algorithms increase the total number of …

A Study Of A Smog-Fog-Smog Cycle And The Processing Of Pah And Oxy-Pah By A Fog Cloud, Kalindi Pramod Khadapkar

LSU Master's Theses

Fog is a multiphase dynamic system which can provide a setting for various physicochemical processes affecting the fate of various organic pollutants such as polycyclic aromatic hydrocarbons (PAH) and their oxygenated forms (oxy-PAH) in the atmosphere. This study focuses on the processing of PAH and oxy-PAH during a smog-fog-smog cycle. Two field campaigns were carried out during the winters of year 2010 and year 2011 in the Central Valley of California, sampling two fog events in Fresno and five fog events in Davis. To study the transformations and distributions of PAH and oxy-PAH, different atmospheric species (fog water, gas phase, …

In-Wheel Motors: Express Comparative Method For Pmbl Motors, Pavani Gottipati

LSU Doctoral Dissertations

One of the challenges facing the electric vehicle industry today is the selection and design of a suitable in-wheel motor. Permanent Magnet Brushless (PMBL) motor is a good choice for the in-wheel motor because of its lossless excitation, improved efficiency, reduced weight and low maintenance. The PMBL motors can be further classified as Axial-Flux Twin-Rotor (AFTR) and Radial-Flux Twin-Rotor (RFTR) machines.

The objective of this dissertation is to develop a fast method for the selection of appropriate in-wheel motor depending on wheel size. To achieve this, torque equations are developed for a conventional single-rotor cylindrical, twin-rotor axial-flux and twin-rotor radial-flux …

Characterization Of Foam Flow In Pipes Using Two Flow Regime Concept, Rahul Narayanrao Gajbhiye

LSU Doctoral Dissertations

The objective of this study is to investigate the characteristics of foam flow behavior in pipes in a wide range of experimental conditions, including two pipe materials (stainless steel and nylon pipes with about 0.36 - 0.38 inch in inner diameter and 12 ft in length), three surfactant formulations (Cedepal FA-406, Stepanform-1050, and Aquet-944), and three surfactant concentrations (0.1, 0.5, and 5 wt%). The concept of “two foam-flow regimes”, consisting of high-quality regime and low-quality regime, is at the heart of interpreting the experimental data. The experimental results in horizontal pipes showed the presence of two distinct high-quality and low-quality …

Analysis Of Static Lateral Load Test Of Battered Pile Group At I-10 Twin Span Bridge, Binay Pathak

LSU Master's Theses

In offshore structures, battered piles have been used as an alternative to vertical piles because of their capability in resisting higher lateral loads. The foundations of the newly built I-10 Twin Span Bridge over Lake Pontchartrain, LA, mostly consist of battered piles group. Understanding the behavior of these batter pile group foundations under lateral loading is very important to the design of highway bridge foundations. This study focuses on the evaluation of the lateral responses of battered pile group subjected to lateral loading and assessment of the current design methodology used for the design of I-10 Twin Span Bridge over …

Embedded Piezoelectric Fiber Composite Sensors For Applications In Composite Structures, Hari Prasad Konka

LSU Doctoral Dissertations

Health monitoring of the composite structures is an important issue that must be addressed. Embedded sensors could be an effective way to monitor the health of composite structures continuously and which could also avoid the catastrophic failures of composite structures. Piezoelectric-fiber-composite sensors (PFCS) made from micro-sized Lead Zirconate Titanate (PZT) fibers have great advantages over the traditional bulk PZT sensors for embedded sensor applications. PFCS as an embedded sensor will be an ideal choice to continuously monitor the stress/strain levels and health conditions of composites. This work presents a critical study on using PFCS as an effective embedded sensor within …

Simulation Study Of Sweep Improvement In Heavy Oil Co2 Floods, Venu Gopal Rao Nagineni

LSU Master's Theses

Enhanced oil recovery by CO2 injection is a common application used for light oil reservoirs since CO2 is relatively easily miscible with light oils. CO2 flooding in heavy oil reservoirs is often uneconomic due to unfavorable mobility ratios. Reservoir heterogeneity further complicates the process as CO2 channels through high permeability layers leading to premature breakthrough. However, this can be controlled by choosing a suitable modification to the CO2 injection process enabling better sweep efficiencies, and making the process economic. The current work focuses on two such methods; water-alternating-gas injection (WAG) and profile modification by blocking gas flow in the high …

Analyzing And Predicting Processor Vulnerability To Soft Errors Using Statistical Techniques, Lide Duan

LSU Doctoral Dissertations

The shrinking processor feature size, lower threshold voltage and increasing on-chip transistor density make current processors highly vulnerable to soft errors. Architectural Vulnerability Factor (AVF) reflects the probability that a raw soft error eventually causes a visible error in the program output, indicating the processor’s susceptibility to soft errors at architectural level. The awareness of the AVF, both at the early design stage and during program runtime, is greatly useful for designing reliable processors. However, measuring the AVF is extremely costly, resulting in large overheads in hardware, computation, and power. The situation is further exacerbated in a multi-threaded processor environment …

Molecular Dynamics Simulation Studies Of Surface-Stress Effects In Metallic Nanostructures, Jijun Lao

LSU Doctoral Dissertations

Using molecular dynamics (MD) simulations we investigate the surface-stress-induced structural transformations and pseudoelastic behavior in palladium (Pd) crystalline nanowires. For a <100> initial crystal orientation our studies indicate that the surface stress can cause Pd nanowires to spontaneously undergo structural changes with characteristics that are determined by the wire cross-sectional area. Specifically, when the cross-sectional area is below 2.18nm x 2.18nm the wire changes spontaneously its crystal structure from the initial fcc structure to a body-centered-tetragonal (bct) structure. In wires of larger cross-sectional area (i.e., 2.57nm x 2.57nm) the structural transformation is achieved via a spontaneous lattice reorientation leading to an …

“Hydraulic Fracturing Efficiency In The Olmos Sand Formation”, Lauren N. Fogarty

Honors Capstones

No abstract provided.

Studies Of Hydrophobic Organic Pollutant Interactions With Cyclodextrin: Implication For Groundwater Remediation, Heng Gao

LSU Doctoral Dissertations

Henry’s Law constants of several common, subsurface hydrophobic organic pollutants (HOPs) including trichloroethylene (TCE), perchloroethylene (PCE) and benzene, toluene, ethylbenzene and o-xylene (BTEX), were measured over a range of temperatures (35, 45, 55 and 65°C) and cyclodextrin (CD) concentrations (0, 10, 20, 50 and 100 g L-1). In aqueous CD solutions, Henry’s constant values decrease by a power law relationship with increasing CD concentration due to an apparent solubility enhancement caused by HOP partitioning to the hydrophobic cavity of CD molecules. The temperature dependence of air-water partitioning under the influence of CD was well described by the van’t Hoff equation …

Influence Of Unstable Soil Movement On Pile-Founded Concrete Floodwalls And A Resulting Design Methodology, Richard James Varuso

LSU Doctoral Dissertations

Efforts are underway in the New Orleans area to raise the elevations of its levee system to combat the effects of hurricane storm surge. When complete, the majority of the system will be comprised of a combination of levees, sheet pile I-Walls, floodgates, and pile-supported concrete floodwalls, commonly referred to as T-Walls. Given the magnitude of the hydrostatic forces associated with storm surge, global instability is failure mechanism that must be considered in the design of T-Walls. In the past, it was assumed that these forces would be resisted by the T-Wall’s sheet pile cut-off wall. Recent literature review and …

Macroinstability And Perturbation In Turbulent Stirred Tank Flows, Somnath Roy

LSU Doctoral Dissertations

Impeller stirred tank reactors (STRs) are commonly used in the chemical processing industries for a variety of mixing and blending technologies. In this research, a numerical study of flow and mixing inside turbulently agitated STRs are carried out. An immersed boundary method (IBM) is utilized to represent moving impeller geometries in the background of multi-block structured curvilinear fluid. The IBM This curvilinear-IBM methodology is further combined with the large eddy simulation (LES) technique to address the issue of modeling unsteady turbulent flows in the STR. Verification of the combined IBM-LES implementation strategy in curvilinear coordinates is done through comparisons with …

Designing A Whey Protein Based Material As A Scaffold For Bone Regeneration, Mia Dvora

LSU Doctoral Dissertations

A novel gel material was designed and optimized for use as a bone tissue regeneration scaffold. Whey protein isolate (WPI), the primary component of the material, underwent considerable testing for conformity to a set of known material characteristics required for application in bone regeneration. WPI gels of different compositions were fabricated by thermally inducing gelation of high-concentration protein suspensions, and characterized for compressive strength and modulus, hydration swelling and drying properties, mechanical behavior change due to polysaccharide additives, and intrinsic pore network structure. The gels were also tested for their compatibility with MC3T3-E1 cells, and interactions such as cell adhesion, …