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Non-Linear Kinematic Hardening Model For Multiaxial Cyclic Plasticity, Marcio Costa Araujo
Non-Linear Kinematic Hardening Model For Multiaxial Cyclic Plasticity, Marcio Costa Araujo
LSU Master's Theses
A model of kinematic work hardening based on Frederick and Armstrong (1966), Phillips and Weng (1975), Chaboche (1979), and Voyiadjis and Basuroychowdhury (1998) is proposed for metal like behavior materials. In this proposed model, ratcheting is taken into account through the observation of the backstress evolution equation, modified by the addition of a new term, . Experimental observations made by Phillips and Lee (1979) showed that the direction of the movement of the center of the yield surface occurs in between the stress rate tensor and the plastic strain rate tensor directions. The new term, added to Chaboche model (1979), …
High Resolution Modeling Of Transport In Porous Media, Guangli Liu
High Resolution Modeling Of Transport In Porous Media, Guangli Liu
LSU Doctoral Dissertations
This dissertation presents research on the pore-level modeling of transport in porous media. The focus of this work is on high-resolution modeling, a rigorous approach that represents detailed geometry and first-principle physics at the streamline scale. Three major topics are presented in this dissertation: an efficient approach for solving Stokes flow in essentially arbitrary disordered porous media, high-resolution versus network simulations of dispersion phenomena, and a stochastic model for solving interfacial mass transfer from source spheres in porous media. First an approach was developed for solving the Stokes flow problem in a comparatively large, very heterogeneous two-dimensional porous media with …
Cementitious Stabilization Of Soils In The Presence Of Sulfate, Lan Wang
Cementitious Stabilization Of Soils In The Presence Of Sulfate, Lan Wang
LSU Doctoral Dissertations
Winn Rock (anhydrite, CaSO4) comes from a quarry in Winn Parish in north Louisiana. Gravel from the quarry has been used extensively as a surface course on local parish and logging roads. Stabilization of these roads with Type I Portland cement followed by an overlay by asphaltic concrete sometimes resulted in heaving. The causes for heaving and possible solutions were investigated. In the laboratory 2" x 4" molds of Winn Rock containing soil were prepared and cured in water bath at 40°C, sealed plastic bag at room temperature, and air. Molds were prepared with 5% to 20% cementitious material. The …
Development Of Catalytic Processes For Aromatic Amides And Carboxylic Acids, Yujun Song
Development Of Catalytic Processes For Aromatic Amides And Carboxylic Acids, Yujun Song
LSU Master's Theses
New catalysts were prepared and studied for: (1) a model amidation with a hindered amine, diethylamine (DEA), to N,N¡¯-diethyltoluamide (DEET); (2) the oxidation of m-xylene (MX) to DEET¡¯s alkylaromatic precursor, m-toluic acid (MTA). In both cases the goal was to reduce waste associated with current processes. Thermodynamic analyses showed that the amidation to produce DEET from MTA and DEA was an equilibrium limited reaction with equilibrium constants (Ke) less than 41 at temperatures below 320¡ÆC. The kinetics on silica-supported titanium (¥³) (triethanolaminato)-isopropoxide (Tyzor TE), calcium hydroxyapatites and silica supported tungsten heteropolyacids were studied using a continuous reactor. Both porous hydroxyapatites …
A Screening Assessment Of Dissolved Air Flotation For Control Of Nonindigenous Invasive Species Transported In Shipping Ballast Water, Eng Chong Voon
A Screening Assessment Of Dissolved Air Flotation For Control Of Nonindigenous Invasive Species Transported In Shipping Ballast Water, Eng Chong Voon
LSU Master's Theses
Uncontrolled discharge of ballast water by vessels has been considered one of the main mechanisms for the introduction of aquatic nuisance species (ANS). The typical size of species found ranges from 0.02 to 10,000 micrometer. This wide range of sizes consists of microorganism (protozoa, dinoflagellates, and cholera), planktonic species, plants, insects, other arthropods, worms, mollusks, and vertebrates. These species either remain suspended in ballast water or settle in ballast tank sediments. Providing treatment for ballast water is a challenging task due to space availability of ships and significant magnitude of flow rates and volumes of ballast water. Currently, open ocean …
The Effect Of Periodic Operation On Biofilters For Removal Of Methyl Ethyl Ketone From Contaminated Air, Charles William Norman
The Effect Of Periodic Operation On Biofilters For Removal Of Methyl Ethyl Ketone From Contaminated Air, Charles William Norman
LSU Master's Theses
In recent years, biofiltration technology has been used at numerous locations worldwide as an air pollution control technology for treating gases contaminated with low concentrations of biodegradable volatile organic compounds (VOCs). At the same time, there have been many reports in the literature of contaminant emissions from biofilters during transient loading conditions. There is currently a need to develop methods for controlling such emissions. Periodically operated bioreactors have been used successfully in treatment of wastewater and soils for several decades to mitigate the effects of uncontrolled unsteady-state loading on waste treatment systems. Such operating strategies have only recently been applied …
A Correlation Between The Optical And Mechanical Properties Of Novel Polysilane/Polysiloxane Nanocomposites, Sungho Lee
A Correlation Between The Optical And Mechanical Properties Of Novel Polysilane/Polysiloxane Nanocomposites, Sungho Lee
LSU Master's Theses
Polysilanes are ¥ò-conjugated conductive polymers with a one-dimensional Si backbone and organic substituted side chains. The conventional Wurtz-type coupling reaction has been used for preparing various alkyl substituted polysilanes, i.e. poly(di-n-hexyl)silane and poly(hexylmethyl)silane. For each polysilane examples with methoxy (-OCH3) and allyl (-CH2CH=CH2) end caps have been prepared. The solution UV absorption characteristics of the polysilanes at room temperature have been measured, from which the wavelength maximum of the UV-VIS absorption and the absorptivity have been obtained. Allyl end capped polysilanes have the same wavelength maximum as methoxy end capped polysilanes. However, the absorptivities of allyl end capped polysilanes are …
Utilization Of Rice Bran By Pythium Irregulare For Lipid Production, Hui Zhu
Utilization Of Rice Bran By Pythium Irregulare For Lipid Production, Hui Zhu
LSU Master's Theses
This research investigated the feasibility of utilizing rice bran as feedstock for submerged fermentation of Pythium irregulare to produce fungal lipids, which contain polyunsaturated fatty acids (PUFAs) including arachidonic acid (AA, C20:4n6) and eicosapentaenoic acid (EPA, C20:5n3). The fungal nutrient requirements, temperature characterization and growth modeling were determined in glucose-yeast extract media. Sixteen media combinations based on a 24 factorial design with four levels of glucose and yeast extract ranged from 1% to 4% and 0.25% to 1%, respectively, and corresponding carbon/nitrogen ratio (C/N) ranged from 4 to 64, were examined. The suitable C/N for Pythium irregulare growth ranged from …
Computing Moments Of A Binary Horizontally/Vertically Convex Image Using Run-Time Reconfiguration, Cheowway Neoh
Computing Moments Of A Binary Horizontally/Vertically Convex Image Using Run-Time Reconfiguration, Cheowway Neoh
LSU Master's Theses
In this thesis, we present a design for computing moments of a binary horizontally/vertically convex image on an FPGA chip, using run-time reconfiguration. We compute the moments of up to third order for a total of 16 moments. We address how run-time reconfiguration speeds up moment computations without taking up huge hardware resources. Since we are considering a binary horizontally/vertically convex image, we look at an alternative method in moment computations that utilizes constant coefficient multipliers. We divide the image into segments and process one segment at a time. We reconfigure the constant coefficient multipliers before processing the next segment. …
Bench-Scale Compost Reactors System And The Self-Heating Capabilities, Michael Alden Vining
Bench-Scale Compost Reactors System And The Self-Heating Capabilities, Michael Alden Vining
LSU Master's Theses
Less expensive bench-scale composting reactor systems which can mimic actual composting process via self-heating are needed. One can achieve such systems without using the expensive temperature feed-back control by properly insulating the bench composting reactors. However, the knowledge of heat generation and transfer in bench composting reactors is essential in properly designing such inexpensive insulation systems. All compost trial temperature profiles illustrated initial elevated temperature levels followed by a slow gradual temperature decreasing phase. Of all of the variables, the airflow rate, the volume and the overall heat transfer coefficient, seem to have the greatest impact on producing thermophilic temperatures. …
Numerical Studies Of Reactive Polymer Flows In Porous Materials, Honggao Liu
Numerical Studies Of Reactive Polymer Flows In Porous Materials, Honggao Liu
LSU Doctoral Dissertations
This dissertation presents a new numerical model of reactive polymer flow in heterogeneous porous media. A moment representation of the log-normal polymer molecular weight distribution is used to model polymer as a multi-component species. Three leading moments are used to simulate the polymer transport and reaction processes in a two-dimensional porous medium. A new operator splitting technique that allows the moment equations for polymerization to be incorporated into a finite-difference transport model is developed. The novelty of this approach is the use of two different dependent variables (for the transport versus reaction parts of the problem). It is significant from …
Impact Of Subject Related Factors And Position Of Flight Control Stick On Acquisition Of Simulated Flying Skills Using A Flight Simulator, Bo-Keun Cho
LSU Doctoral Dissertations
Increasing demand on aviation industry calls for more pilots. Thus, pilot training systems and pilot-candidate screening systems are essential for civil and military flying training institutes. Before actual flight training, it is not easy to determine whether a flight trainee will be successful in the training. Due to the high cost of actual flight training, it would be better if there were low cost methods for screening and training candidates prior to the actual flight training. This study intended to determine if subject related factors and flight control stick position have an impact on acquisition of simulated flying skills using …
Development Of A Magnetite Tracer Protocol For Seasonal Measurement Of Bed Sediment Biodiffusion Coefficients, Paul D. Libbers
Development Of A Magnetite Tracer Protocol For Seasonal Measurement Of Bed Sediment Biodiffusion Coefficients, Paul D. Libbers
LSU Master's Theses
This thesis describes the development of a particle tracer technique for making short-term, in situ measurements of aquatic bed sediment biodiffusion coefficients. The bioturbation process in the upper sediment layers of streams, lakes, estuaries, and the marine environment moves particles and porewater. When present, organic chemicals, metals, colloids, etc., are transported across these layers and exchanges may occur at the sediment-water interface. Fickian biodiffusion coefficients that characterize such particle movements, Db (cm2/yr), are used for assessing chemical diagenesis rates and contaminant fluxes and are specific to each site. Chemical Fate and Transport (CFaT) models, developed for tracking contaminants in aquatic …
Optimal Channel Equalization For Filterbank Transceivers In Presence Of White Noise, Ehab Farouk Badran
Optimal Channel Equalization For Filterbank Transceivers In Presence Of White Noise, Ehab Farouk Badran
LSU Doctoral Dissertations
Filterbank transceivers are widely employed in data communication networks to cope with inter-symbol-interference (ISI) through the use of redundancies. This dissertation studies the design of the optimal channel equalizer for both time-invariant and time-varying channels, and wide-sense stationary (WSS) and possible non-stationary white noise processes. Channel equalization is investigated via the filterbank transceivers approach. All perfect reconstruction (PR) or zero-forcing (ZF) receiver filterbanks are parameterized in an affine form, which eliminate completely the ISI. The optimal channel equalizer is designed through minimization of the mean-squared-error (MSE) between the detected signals and the transmitted signals. Our main results show that the …
The Effects Of Local Hydrodynamics On Mass Transfer In Disordered Porous Media, Gang Guo
The Effects Of Local Hydrodynamics On Mass Transfer In Disordered Porous Media, Gang Guo
LSU Doctoral Dissertations
Interfacial mass transfer in disordered media was studied experimentally and numerically. The dissolution of solid benzoic acid spheres in packed columns showed the existence of spatial variations in mass transfer coefficients in monodisperse and polydisperse packings at the same overall Peclet number. The concept of a local Peclet number (single-particle average) was introduced to quantify the effect of local hydrodynamics on local mass transfer. Correlations between Sherwood number and Peclet number having the form Shi=A·(xiPe)m were used to quantify data from various sites in each packing. These experiments also showed that the exponent m varies …
Quantification Of The Spatial Gradient Of Local Volume Fraction From Tomography Images, Yongping Wang
Quantification Of The Spatial Gradient Of Local Volume Fraction From Tomography Images, Yongping Wang
LSU Master's Theses
Asphalt concrete has three constituents: aggregate, asphalt binder and air voids. In the mixture, aggregates serve as a skeleton of the mixture; asphalt serves as a binder to hold the aggregates together; and air voids prevent asphalt concrete from bleeding to avoid plastic mixes. The properties of asphalt concrete are controlled by the interaction of these three components. In asphalt concrete, asphalt binder, voids and aggregates are not uniformly distributed. The local volume fractions of these constituents vary with spatial locations. As a result, there exist a spatial gradient of the local volume fractions between two locations. Due to the …
Wastewater Plume Dynamics And Bacteria Transport Within The Marshland Upwelling System, Stephen David Richardson
Wastewater Plume Dynamics And Bacteria Transport Within The Marshland Upwelling System, Stephen David Richardson
LSU Master's Theses
The marshland upwelling system (MUS) serves as an alternative onsite method for the treatment of domestic wastewater derived from coastal communities. Previous studies on the MUS have focused on the efficacy of the system for the removal of fecal pathogens from settled and secondarily-treated wastewater sources. The objectives of this research were to: 1) characterize the extent of wastewater migration within the MUS, 2) evaluate the effectiveness of the MUS in removing fecal bacteria, 3) identify the mechanisms responsible for fecal coliform retention within the subsurface, and 4) describe the transport of fecal coliforms in a sand media based on …
Fine Aggregate Characterization Using Digital Image Analysis, Tongyan Pan
Fine Aggregate Characterization Using Digital Image Analysis, Tongyan Pan
LSU Master's Theses
A comprehensive literature review shows that performance of hot mix asphalt (HMA) is influenced by properties of aggregate. Current situation is that only limited efforts were dedicated to aggregate tests and criteria on aggregate, compared to researches on new binder tests, especially to that of fine aggregate. Superpave (Superior Performing Asphalt Pavement) tests/criteria on aggregate need to reflect those properties that influence performance. Representatives of the aggregate industry and the Superpave Mixture/Aggregate ETG (Expert Task Group) have reached the consensus for the need to improve aggregate tests and criteria as one of the most needed aspects left to complete in …
Liga Mold Insert Fabrication Using Su-8 Photoresist, Jian Zhang
Liga Mold Insert Fabrication Using Su-8 Photoresist, Jian Zhang
LSU Master's Theses
The LIGA process potentially enables economic mass-production of devices with high aspect ratio geometry. Central to the LIGA process is the fabrication of high quality LIGA molds. But in the traditional LIGA mold insert fabrication process, the x-ray photoresist poly-methyl-methacrylate (PMMA) is not highly sensitive to x-rays and a thick piece of PMMA sheet (>1mm) needs too much time to get exposed (bottom dose: 3500J/cm3), which results in excessive cost/ fabrication difficulty of the mold insert. Thus, in this thesis a negative photoresist SU-8 was tested as an x-ray photoresist in the LIGA fabrication process. SU-8 is much more …
Analysis Of Diagnostic Testing Of Sustained Casing Pressure In Wells, Rong Xu
Analysis Of Diagnostic Testing Of Sustained Casing Pressure In Wells, Rong Xu
LSU Doctoral Dissertations
Over 8,000 wells in the Gulf of Mexico exhibit sustained casing pressure (SCP). SCP is defined as “any measurable casing pressure that rebuilds after being bled down, attributable to cause(s) other than artificially applied pressures or temperature fluctuations in the well”. The Minerals Management Service (MMS) regulations consider SCP hazardous and, in principle, require its elimination. In some cases the agency may allow continuing production at a well with SCP by granting a temporary “departure” permit. The departure permits are based on diagnostic tests involving pressure bleed-down through a 0.5-inch needle valve followed by closing the valve and recording pressure …
Development Of A Phosphorus Management Model To Address Filamentous Algae In A Shallow, Subtropical, Urban Hypereutrophic Lake, Jennifer Eileen Ruley
Development Of A Phosphorus Management Model To Address Filamentous Algae In A Shallow, Subtropical, Urban Hypereutrophic Lake, Jennifer Eileen Ruley
LSU Master's Theses
City Park Lake is a shallow, subtropical, urban hypereutrophic lake located in Baton Rouge, Louisiana. By the late 1970’s, this artificial lake had experienced extreme eutrophication and suffered from frequent algal blooms and fish kills. Restoration of City Park Lake occurred in 1983 and consisted of dredging nutrient-laden sediments and the rehabilitation of sewage pipelines. Pre- and post-restoration water quality monitoring programs have provided valuable information by which to gage the long-term success of the restoration work. Following the restoration effort, dramatic improvements were observed in the lake including lower nitrogen, phosphorus and chlorophyll-a concentrations, reduced frequencies in algal blooms …
Mechanism Of The Nicofe Ternary Alloy Deposition, Yun Zhuang
Mechanism Of The Nicofe Ternary Alloy Deposition, Yun Zhuang
LSU Doctoral Dissertations
Electrodeposited NiCoFe ternary alloys are of interest for their magnetic and thermophysical properties. The reaction rates and resulting composition and current efficiency are often determined empirically, due to a lack of understanding of the electrodeposition mechanism and coupled mass transport. Therefore, the effects of electrolyte concentration, bulk pH and solution agitation are studied over a wide range of applied current densities to investigate the interrelated behavior of the partial reaction rates. The Fe rate during alloy deposition is independent of Co2+ and Fe2+ bulk concentrations, but is enhanced compared with its single metal rate. Both catalytic and inhibiting effects are …
Improvement Of Resonant Harmonic Filter Effectiveness In The Presence Of Distribution Voltage Distortion, Herbert L. Ginn
Improvement Of Resonant Harmonic Filter Effectiveness In The Presence Of Distribution Voltage Distortion, Herbert L. Ginn
LSU Doctoral Dissertations
Resonant harmonic filters (RHFs), are the most common devices installed in distribution systems for reducing distortion caused by harmonic generating loads. When such filters are applied in systems with a distorted distribution voltage their effectiveness may decline drastically. This dissertation explores the causes of degradation of RHFs effectiveness and suggests methods of their improvement both by optimization algorithms and by modification of the filter structure. An optimization based design method is developed for the conventional RHF. It takes into consideration the interaction of the filter with the distribution system and provides a filter which gives the maximum effectiveness with respect …
Parametric And Sensitivity Analysis Of A Vibratory Automobile Model, Kanika Nicole Vessel
Parametric And Sensitivity Analysis Of A Vibratory Automobile Model, Kanika Nicole Vessel
LSU Master's Theses
Vibration response is an important aspect of any engineering problem. This thesis deals with developing a method to obtain the vibration, parametric and sensitivity of an automobile analyzed as a 2-DOF rigid body system with damping. The focus of the vibration analysis is to obtain the poles, eigenvectors, and natural frequencies of the system. The parametric analysis gave information on how the natural frequency is affected when one of the parameters is perturbed. Information about how much the system is affected by the change in one parameter is what is obtained from the sensitivity analysis. The theoretical solution contained in …
Data Mining And Knowledge Discovery: A Guided Approach Base On Monotone Boolean Functions, Vetle Ingvald Torvik
Data Mining And Knowledge Discovery: A Guided Approach Base On Monotone Boolean Functions, Vetle Ingvald Torvik
LSU Doctoral Dissertations
This dissertation deals with an important problem in Data Mining and Knowledge Discovery (DM & KD), and Information Technology (IT) in general. It addresses the problem of efficiently learning monotone Boolean functions via membership queries to oracles. The monotone Boolean function can be thought of as a phenomenon, such as breast cancer or a computer crash, together with a set of predictor variables. The oracle can be thought of as an entity that knows the underlying monotone Boolean function, and provides a Boolean response to each query. In practice, it may take the shape of a human expert, or it …
Bayesian Updating Of Simulated Household Travel Survey Data For Small/Medium Metropolitan Areas, Sirisha Murthy Kothuri
Bayesian Updating Of Simulated Household Travel Survey Data For Small/Medium Metropolitan Areas, Sirisha Murthy Kothuri
LSU Master's Theses
This thesis tests an approach for generating simulated travel survey data that has local characteristics incorporated in it. Travel survey data are generally required for estimating and calibrating travel demand models for a region. The high cost associated with travel surveys puts them beyond the budget of most small/medium MPOs. Therefore simulation of travel survey data provides a viable alternative for these data starved regions to generate data. The simulated data is produced by combining socio-demographic data along with a national survey data set. Updating the simulated data distributions with the distributions obtained by surveying a small sample of local …
Application Of Anoxic/Aerobic (A/A) Biological Treatment To Swine Wastewater, Dale G. Frederick
Application Of Anoxic/Aerobic (A/A) Biological Treatment To Swine Wastewater, Dale G. Frederick
LSU Master's Theses
Residential expansion into traditionally rural areas, environmental issues and increasing integration and farm sizes, have placed steadily increasing pressure and demands on the modern pork producer. Waste management and odor control have become important priority issues. In this research, a controllable field scale biological treatment system was designed, constructed and investigated. The anoxic/aerobic (A/A) system consisted of an anoxic reactor, which receives the raw swine waste, in series with an aerobic reactor. The design of the system require the heterotrophic bacteria in the anoxic reactor to oxidize the organic carbon to carbon dioxide utilizing nitrate as the terminal electron acceptor …
Intrinsic Biodegradation Potential Of Crude Oil In Salt Marshes, Julius Enock
Intrinsic Biodegradation Potential Of Crude Oil In Salt Marshes, Julius Enock
LSU Master's Theses
Understanding the influence of different perturbations on the fate of spilled oil in marine ecosystems is useful in assessing the environmental impact and remedial investigation. The effect of flooding and spill recurrence on the fate of an experimental crude oil spill (2 L/m2) was investigated using salt marsh intact cores, incubated for about 3 months, by monitoring residual petroleum hydrocarbons, heterotrophic microbial activity (fluorescein diacetate assay) and soluble organic carbon (SOC). For the flooding study, biodegradation rate of crude oil (with half-lives varying between 16.50 and 49.51 days and turnover times between 23.81 and 71.43 days) and microbial …
A Variable Response Time Lag Module For Car Following Models Using Fuzzy Set Theory, Yilmaz Hatipkarasulu
A Variable Response Time Lag Module For Car Following Models Using Fuzzy Set Theory, Yilmaz Hatipkarasulu
LSU Doctoral Dissertations
Since the 1950s, car following phenomena have been studied and analyzed, resulting in various models and algorithms. In general, the car following process has been defined as a stimulus-response relationship in which the driver of the following vehicle reacts to the actions of the lead vehicle after a time lag. One of the fundamental assumptions that underlie car following theory is that the driver response time lag is always a constant value for the driver at all times, regardless of level of detail of the model. Assumption of a constant time lag value introduces a number of broad assumptions however, …
Nitrification Rates In A Reversed-Flow, Spouted-Bed, Bioreactor Applied To Recirculating Aquaculture Systems, Jonathan Thomas Scott
Nitrification Rates In A Reversed-Flow, Spouted-Bed, Bioreactor Applied To Recirculating Aquaculture Systems, Jonathan Thomas Scott
LSU Master's Theses
The effects of media selection and organic loading on nitrification rates in a reversed-flow, three-phase, spouted-bed, bioreactor with draft-tube (A-1 Aquaculture Continuous-Cleaning Multifunctional Biofilter or CCMB) were studied. Experiments were conducted on three identical recirculating aquaculture systems (RAS) each having a CCMB unit with a unique plastic pelletized media and operated over five successive trials with varying components and operating conditions. Based upon organic loading, three of the five trials were grouped into two organic loading regimes of approximately 91 mg/L COD and 149 mg/L COD. Comparing nitrification rates against the three media types by organic loading showed that media …