Engineering Commons^™

Molecular Dynamics Of Interfacial Phenomena At Air/Ice, Air/Water, And Air/Salt Water Interfaces, Thilanga Prabhash Liyana Arachchi

LSU Doctoral Dissertations

The purpose of this research is to investigate the adsorption of organic contaminants, namely polycyclic aromatic hydrocarbons (PAHs) and green leaf volatiles (GLVs), as well as their interactions with reactive oxygen species (ROSs) on atmospheric air/water and air/ice interfaces. In another series of projects, we studied several intermediate and semi-volatile organic compounds from oil (IVOCs and SVOCs, e.g., alkanes with 17-31 carbon atoms), surfactants and dispersants at air/salt water interfaces. These simulations are relevant to understand the fate of these compounds during the recent 2010 Deepwater Horizon (DWH) oil spill. The adsorption of gas-phase aromatics (benzene, naphthalene and phenanthrene), ROSs …

Silver Nanoparticles As Drug Delivery Systems, Ammar Tahseen Qureshi

LSU Doctoral Dissertations

The goal of this project is to study the potential applications of silver nanoparticles (SNPs) in the medical device and pharmaceutical industries. Bone cements have been used in the orthopedic surgeries for many years to anchor prosthetics while filling up the spaces between the prostheses and bone. Antibiotics are an active component of bone cements but the increasing bacterial resistance to these antibiotics and difficulty of shaping and molding the bone cements increases the need for new antimicrobial biomaterials. Adult stem cell based regenerative therapies have been one of the most widely researched areas of tissue engineering. This is due …

Activity Of Halide-Free Flux At Copper And Tin Surfaces, Guoying Qu

LSU Master's Theses

The activity of halogen-free carboxylic acid flux is considered one of the most important aspects in controlling flip chip joint quality recently. In this work, we examined the CuOx removal effectiveness of carboxylic acid solutions at Cu substrates using electrochemical methods at elevated temperatures from 100ºC to 180ºC. Reaction kinetics of CuOx removal were investigated by chronopotentiometry and gravimetric analysis. FTIR was used to study the surface chemistry, and spectrophotometry was used to understand reactant and product solubility. Kinetics of carboxylic acid solution such as adipic acid or maleic acid in polyethylene glycol (PEG) with and without complexing agents such …

The Uplift Resistance Of Spartina Alterniflora In A Louisiana Salt Marsh, James Madison Bouanchaud Iii

LSU Master's Theses

The uprooting resistance of Spartina Alterniflora was measured in Terrebonne Bay and Bay Jimmy, both of which are located in Louisiana. The parameters collected included plant uprooting resistance, stem diameter, and stem height. Seasonal variations and site specific properties were considered. A device was designed and constructed that was able to perform the specific testing under the constraints of the field site. The device consisted of a winch mounted to a tripod and connected to an inline load cell to measure the uprooting resistance. The data sets were analyzed to determine the relationship between the uprooting resistance and the physical …

Electric Field Influence On The Combustion Of Fuel Droplets, Solomon Benghan

LSU Master's Theses

Improving the combustion efficiency of fuels in combustion devices has become imperative in the face of the diminishing rate of the discovery of new energy sources and an ever increasing demand for energy. While there are other ways of improving combustion efficiency, this study investigated the effect of electric field on the combustion of fuel droplets. In order to model the physics of the problem, a mass transfer evaporation model, heat transfer evaporation model and a simple burning droplet model were considered and their result compared to existing result from literature. A burning rate constant of 1.380mm2/s, 14.910mm2/s and 0.612mm2/s …

Psychological Behavior Analysis Using Advanced Signal Processing Techniques For Fmri Data, Charisma Dionne Edwards

LSU Doctoral Dissertations

Psychological analysis related to voluntary reciprocal trust games were obtained using functional magnetic resonance imaging (fMRI) hyperscanning for 44 pairs of strangers throughout 36 trust games (TG) and 16 control games (CG). Hidden Markov models (HMMs) are proposed to train and classify the fMRI data acquired from these brain regions and extract the essential features of the initial decision of the first player to trust or not trust the second player. These results are evaluated using the different versions of the multifold cross-validation technique and compared to other speech data and other advanced signal processing techniques including linear classification, support …

Time Resolved Gain And Excess Noise Properties Of Ingaas/Inalas Avalanche Photodiodes With Cascaded Discrete Gain Layer Multiplication Regions, Georges M. Williams, David A. Ramirez, Majeed M. Hayat, Andrew S. Huntington

Electrical and Computer Engineering Faculty Research and Publications

To predict pulse detection performance when implemented in high speed photoreceivers, temporally resolved measurements of a 10-stage InAlAs/InGaAs single carrier multiplication (SCM) avalanche photodiode (APD)'s avalanche response to short multi-photon laser pulses were explained using instantaneous (time resolved) pulse height statistics of the device's impulse response. Numeric models of the junction carrier populations as a function of the time following injection of a primary photo-electron were used to create the probability density functions (pdfs) of the instances of the avalanche buildup process. The numeric pdfs were used to generate low frequency gain and excess noise models, which were in good …

Rotor Bar Fault Monitoring Method Based On Analysis Of Air-Gap Torques Of Induction Motors, Aderiano Da Silva, Nabeel Demerdash, Richard J. Povinelli

Electrical and Computer Engineering Faculty Research and Publications

A robust method to monitor the operating conditions of induction motors is presented. This method utilizes the data analysis of the air-gap torque profile in conjunction with a Bayesian classifier to determine the operating condition of an induction motor as either healthy or faulty. This method is trained offline with datasets generated either from an induction motor modeled by a time-stepping finite-element (TSFE) method or experimental data. This method can effectively monitor the operating conditions of induction motors that are different in frame/class, ratings, or design from the motor used in the training stage. Such differences can include the level …

Forecasting Natural Gas Demand For Electric Power Generation, Ronald H. Brown, George Corliss, Richard J. Povinelli

Electrical and Computer Engineering Faculty Research and Publications

No abstract provided.

Effect Of Hydrodynamic Force On Microcantilever Vibrations: Applications To Liquid-Phase Chemical Sensing, I. Dufour, E. Lemaire, B. Caillard, H. Debeda, C. Lucat, Stephen M. Heinrich, Fabien Josse, O. Brand

Electrical and Computer Engineering Faculty Research and Publications

At the microscale, cantilever vibrations depend not only on the microstructure’s properties and geometry but also on the properties of the surrounding medium. In fact, when a microcantilever vibrates in a fluid, the fluid offers resistance to the motion of the beam. The study of the influence of the hydrodynamic force on the microcantilever’s vibrational spectrum can be used to either (1) optimize the use of microcantilevers for chemical detection in liquid media or (2) extract the mechanical properties of the fluid. The classical method for application (1) in gas is to operate the microcantilever in the dynamic transverse bending …

Risk Assessment Of Driving Safety In Long Scaled Bridge Under Severe Weather Conditions, Shengdi Chen

USF Tampa Graduate Theses and Dissertations

Weather conditions have certain impacts on roadway traffic operations, especially traffic safety. Bridges differ from most surface streets and highways in terms of their physical properties and operational characteristics. This research assess the driving risk under different weather conditions through focus group firstly, then it develops a multi-ordered discrete choice model that is used to analyze and evaluate driving risks under both single and dual weather conditions. The data is derived from an extensive questionnaire survey in Shanghai. And the questionnaire includes those factors related to roadway, drivers, vehicles, and traffic that may have significant impacts on traffic safety under …

A Study On Lane-Change Recognition Using Support Vector Machine, Weiping Deng

USF Tampa Graduate Theses and Dissertations

This research focuses primary on recognition of lane-change behaviors using support vector machines (SVMs). Previous research and statistical results show that the vast majority of motor vehicle accidents are caused by driver behavior and errors. Therefore, the interpretation and evaluation of driver behavior is important for road safety analysis and improvement. The main limit to understanding driver behavior is the data availability. In particular, a full-scale lane-change data set is difficult to collect in a real traffic environment because of the safety and cost issues. Considering the data demands of the recognition model development and the obstacles of field data …

Geometric Optimization Of Retroreflective Raised Pavement Markers, Lukai Guo

USF Tampa Graduate Theses and Dissertations

As the field service life of retroreflective raised pavement marker (RRPM) is much shorter than expected, it is necessary to identify the causes and thus improve the RRPM structural design to mitigate the main failure modes, such as poor retention from pavements, structural damage, and loss of retroreflectivity. One strategy for extending RRPM service life is to enhance RRPM geometric characteristics to decrease critical stresses in markers. The main purpose of this thesis is to analyze the relationship between stresses, failure modes, and RRPM profiles. Based on this research, some measures are suggested in order to avoid corresponding failure modes …

Analytical And Numerical Modeling Of Assembly Procedures Of Steel Fulcra Of Bascule Bridges, Sriharsha Garapati

USF Tampa Graduate Theses and Dissertations

To model shrink-fitting in metal components, an analytical model for two long compound cylinders with temperature dependent material properties and interference between them is developed for calculating transient temperatures and stresses. A finite element model is developed for the same geometry which incorporated the temperature dependent material properties. A convergence study is performed on the finite element and analytical model. The finite element model is validated by comparing the approximations of finite element model with the analytical solution.

In an assembly procedure of fulcrums for bascule bridges, called AP1, the trunnion is shrink-fitted into a hub, followed by shrink fitting …

Embodied Energy And Carbon Footprint Of Household Latrines In Rural Peru: The Impact Of Integrating Resource Recovery, Christopher M. Galvin

USF Tampa Graduate Theses and Dissertations

Over seventy percent of the 2.5 billion people who still lack access to basic sanitation worldwide live in rural areas (WHO/UNICEF, 2012). Despite concerns of water scarcity, resource depletion, and climate change little research has been conducted on the environmental sustainability of household sanitation technologies common in rural areas of developing countries or the potential of resource recovery to mitigate the environmental impacts of these systems. The environmental sustainability, in terms of embodied energy and carbon footprint, was analyzed for four household sanitation systems: (1) Ventilated Improved Pit (VIP) latrine, (2) pour-flush latrine, (3) composting latrine, and (4) biodigester latrine. …

Assessment Of A Modified Double Agar Layer Method To Detect Bacteriophage For Assessing The Potential Of Wastewater Reuse In Rural Bolivia, Sakira N. Hadley

USF Tampa Graduate Theses and Dissertations

Water scarcity is a global concern that impacts many developing countries, forcing people to depend on unclean water sources for domestic, agricultural, and industrial needs. Wastewater is an alternative water source that contains nutrients needed for crop growth. Wastewater reuse for agriculture can cause public health problems because of human exposure to pathogens. Pathogen monitoring is essential to evaluate the compliance of wastewater with established World Health Organization (WHO) and U.S. Environmental Protection Agency (EPA) wastewater reuse guidelines. Indicator organisms are commonly used to detect pathogens in water and wastewater because they are quick and easy to measure, non-pathogenic, and …

Structured Materials For Catalytic And Sensing Applications, Selma Hokenek

USF Tampa Graduate Theses and Dissertations

The optical and chemical properties of the materials used in catalytic and sensing applications directly determine the characteristics of the resultant catalyst or sensor. It is well known that a catalyst needs to have high activity, selectivity, and stability to be viable in an industrial setting. The hydrogenation activity of palladium catalysts is known to be excellent, but the industrial applications are limited by the cost of obtaining catalyst in amounts large enough to make their use economical. As a result, alloying palladium with a cheaper, more widely available metal while maintaining the high catalytic activity seen in monometallic catalysts …

Effect Of Solids Retention Time On The Denitrification Potential Of Anaerobically Digested Swine Waste, Maureen Njoki Kinyua

USF Tampa Graduate Theses and Dissertations

Three continuously stirred tank reactors (CSTR) were operated in semi continuous mode treating swine waste using anaerobic digestion. The reactors were used to test the effect of solid retention time (SRT) on CH4 yield, total ammonia nitrogen (TAN) concentrations, % volatile solids (VS), chemical oxygen demand (COD) and volatile fatty acids (VFA) removal, readily biodegradable COD concentration and the denitrification potential for the effluent in a biological nutrient removal (BNR) system. During Phase I of the study, the three reactors were operated at the same 28 day SRT for 16 weeks. SRTs were then changed during the 12 week Phase …

Development Of Novel Nano-Composite Membranes As Introduction Systems For Mass Spectrometers: Contrasting Nano-Composite Membranes And Conventional Inlet Systems, Luis Miranda

USF Tampa Graduate Theses and Dissertations

This dissertation presents the development of novel nano-composite membranes as introduction systems for mass spectrometers. These nano-composite membranes incorporate anodic aluminum oxide (AAO) membranes as templates that can be used by themselves or modified by a variety of chemical deposition processes. Two types of nano-composite membranes are presented. The first nano-composite membrane has carbon deposited within the pores of an AAO membrane. The second nano-composite membrane is made by coating an AAO membrane with a thin polymer film. The following chapters describe the transmission properties these nano-composite membranes and compare them to conventional mass spectrometry introduction systems. The nano- composite …

Reliability Assessment Of Ion Contamination Residues On Printed Circuit Board, Minh Tam Tran Nguyen

USF Tampa Graduate Theses and Dissertations

Ion contaminants from Printed Circuit Board (PCB) assembly processes pose a high reliability risk because they result in damaged circuits. Therefore, it is essential to understand the level of ionic species on the electronic circuitry as well as the reliability risks caused by these contaminants. There are a number of approaches available in the industry to assess the reliability risks ; for example, the water drop test (WDT) is one of the techniques used to determine the propensity of an ionic contaminant to cause electrical short failures by dendrite formation. The objective of this research is to determine the time …

Shield Design For Maximum Deformation In Shape-Shifting Surfaces, Daniel Eduardo Perez

USF Tampa Graduate Theses and Dissertations

This research presents the initial studies and results on shield design for Shape-Shifting Surfaces (SSSs) seeking maximum compression and maximum expansion of a unit-cell. Shape-Shifting Surfaces (SSSs) are multilayered surfaces that are able to change shape while maintaining their integrity as physical barriers. SSSs are composed of polygonal unit-cells, which can change side lengths and corner angles. These changes are made possible by each side and corner consisting of at least two different shields, or layers of material. As the layers undergo relative motion, the unit-cell changes shape. In order for the SSS to retain its effectiveness as a barrier, …

Analytical Modeling, Perturbation Analysis And Experimental Characterization Of Guided Surface Acoustic Wave Sensors, Onursal Onen

USF Tampa Graduate Theses and Dissertations

In this dissertation, guided surface acoustic wave sensors were investigated theoretically and experimentally in detail for immunosensing applications. Shear horizontal polarized guided surface acoustic wave propagation for mass loading sensing applications was modeled using analytical modeling and characterized by perturbation analysis. The model verification was performed experimentally and a surface acoustic wave immunosensor case study was presented. The results of the immunosensing were also investigated using the perturbation analysis.

Guided surface acoustic wave propagation problem was investigated in detail for gravimetric (or mass loading) guided wave sensors, more specifically for immunosensors. The analytical model was developed for multilayer systems taking …

Non-Equilibrium Melting And Sublimation Of Graphene Simulated With Two Interatomic Potentials, Brad Steele

USF Tampa Graduate Theses and Dissertations

The mechanisms of the sublimation of graphene at zero pressure and the condensation of carbon vapor is investigated by molecular dynamics (MD) simulations. The interatomic interactions are described by the Reactive Empirical Bond Order potential (REBO). It is found that graphene sublimates at a temperature of 5,200 K. At the onset of sublimation, defects that contain several pentagons and heptagons are formed, that are shown to evolve from double vacancies and stone wales defects. These defects consisting of pentagons and heptagons act as nucleation sites for the gaseous phase. The influence of the interatomic interactions on the sublimation process are …

Flexible Urban Water Distribution Systems, Seneshaw Amare Tsegaye

USF Tampa Graduate Theses and Dissertations

With increasing global change pressures such as urbanization and climate change, cities of the future will experience difficulties in efficiently managing scarcer and less reliable water resources. However, projections of future global change pressures are plagued with uncertainties. This increases the difficulty in developing urban water systems that are adaptable to future uncertainty.

A major component of an urban water system is the distribution system, which constitutes approximately 80-85% of the total cost of the water supply system (Swamee and Sharma, 2008). Traditionally, water distribution systems (WDS) are designed using deterministic assumptions of main model input variables such as water …

Modeling And Design Of Photocatalytic Reactors For Air Purification, Yangyang Zhang

USF Tampa Graduate Theses and Dissertations

Photocatalysis is a promising technique for the remediation of indoor air pollution. Photocatalysis utilizes semiconductor photocatalysts (such as TiO₂ or ZnO) and appropriate light to produce strong oxidizing agents (OH*) that are able to break down organic compounds and inactivate bacteria and viruses. The overall goal of the research is to develop an efficient photocatalytic reactor based on mass transfer for indoor air purification. This study has focused on the enhancement of the effectiveness of the photocatalytic process by the introduction of artificial roughness on the reactor catalyst surface. The major effect of artificial roughness elements on the catalytic …

Environmental Implications Of Pavements: A Life Cycle View, Bin Yu

USF Tampa Graduate Theses and Dissertations

Environmental aspect of pavement, unlike its economic counterpart, is seldom considered in the theoretical study and field practices. As a highly energy and material intensive infrastructure, pavement has great potential to contribute to the environment protection, which, in root, depends on the in-depth understanding of the environmental impacts, holistically and specifically. A life cycle assessment (LCA) model is used to fulfill the goal.

This research firstly carried out extensive literature review of LCA studies on pavement to identify the major research gaps, including: incompleteness of the methodology, controversy of the functional unit, and unawareness of feedstock energy of asphalt, etc. …

Model Pt- And Pd-Based Electrocatalysts For Low Temperature Fuel Cells Applications, Selasi Ofoe Blavo

USF Tampa Graduate Theses and Dissertations

In the search for alternative energy technologies, low temperature fuel cells continue to feature as technologies with the most promise for mass commercialization. Among the low temperature fuel cells, alkaline and proton exchange membrane fuel cells are the most popular. Alkaline fuel cells have typically been used for water generation as well as auxiliary power for space shuttles. Their bulkiness however makes them undesirable for other applications, especially in automobiles, where there is a great demand for alternative technologies to internal combustion engines. Proton exchange membrane fuel cells on the other hand possess numerous qualities including their compact size, high …

Effects Of Solvent Composition And Hydrogen Pressure On The Catalytic Conversion Of 1,2,4,5-Tetrachlorobenzene To Cyclohexane, Margaret Elizabeth Cone

USF Tampa Graduate Theses and Dissertations

Halogenated hydrophobic organic compounds (HHOCs) such as 1,2,4,5-tetrachlorobenzene (TeCB) present a threat to both human health and the environment. The common occurrence and recalcitrant nature of HHOCs as soil contaminants necessitate an effective soil remediation method. Wee and Cunningham (2008, 2011, 2013) proposed a clean-up technology called Remedial Extraction and Catalytic Hydrodehalogenation (REACH), which pairs solvent extraction of HHOC contaminants from soil with catalytic hydrodehalogenation to destroy contaminants. Wee and Cunningham (2008, 2011, 2013) utilized a palladium (Pd) catalyst to hydrodehalogenate TeCB to benzene. However, benzene is still a toxic contaminant. Prior research has demonstrated that Pd-catalyzed hydrodehalogenation (HDH) can …

Design Of A Highly Portable Data Logging Embedded System For Naturalistic Motorcycle Study, Noureddine Elmehraz

USF Tampa Graduate Theses and Dissertations

According to Motorcycle Industrial Council (MIC), in USA the number of owned

motorcycle increased during last few years and most likely will keep increasing. However, the

number of the deadly crash accidents associated with motorcycles is on the rise. Although MIC

doesn't explain why the accident rate has increased, the unprotected motorcyclist gear can be one

of the reasons. The most recent National Highway Traffic Safety Administration (NHTSA)

annual report stated that its data analyses are based on their experiences and the best judgment is

not based on solid scientific experiment [3]. Thus, building a framework for the data acquisition …

Development Of Catalytic Technology For Producing Sustainable Energy, Syed Ali Z Gardezi

USF Tampa Graduate Theses and Dissertations

This dissertation explores catalyst technology for the production of renewable liquid fuels via thermo-chemical conversion of biomass derived syngas. Fischer-Tropsch synthesis is a process for converting syngas, i.e. a mixture of CO and H2, into energy rich long chain hydrocarbons and oxygenated compounds. This synthesis process involves a number of elementary reactions leading to an array of polymeric products. The economic operation of an FTS process lie in the interplay of both catalyst and reactor design. In relation to catalysis, the nature of chemisorbed species, and the fractional availability of active metal sites determines rate, conversion and yield. Similarly, reactor …