Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 16 of 16
Full-Text Articles in Entire DC Network
Solid Removal Schemes And The Rotating Biological Contactor In Recirculating Fish Culture Systems., Aurelio Alfonso Delos Reyes Jr
Solid Removal Schemes And The Rotating Biological Contactor In Recirculating Fish Culture Systems., Aurelio Alfonso Delos Reyes Jr
LSU Historical Dissertations and Theses
The performance of combinations of the Norpac$\sp\circler$ tube RBC with a bead filter (System I), a tube settler (System II), and a sand filter (System III) in pilot scale recirculating systems stocked with tilapia were evaluated and compared. Good fit empirical equations were obtained relating TAN and NO$\sp2$-N (both exponential), and DO (linear) with daily amount of feed. Likewise, linear equations relating bead filter or sand filter pressure with feed, and flow with pressure were obtained. Systems I and II maintained favorable water quality up to the maximum feed load studied of 3 kg/day. System III effectively handled only 1.2 …
Numerical And Experimental Analysis Of Bending And Vibration Of Stiffened Laminated Composite Panels., Aruna Kumar Tripathy
Numerical And Experimental Analysis Of Bending And Vibration Of Stiffened Laminated Composite Panels., Aruna Kumar Tripathy
LSU Historical Dissertations and Theses
The objective of this study is to develop a method of analysis for fiber glass composite skew plates subjected to static and dynamic loading. An investigation has been carried out on the stress and deflection characteristics of stiffened parallelogramic plates with different skew angles. The numerical solution with assumed displacement function was developed using finite element analysis. Experiments using aluminum and Scotchply composite laminated plates were conducted to verify the results. Cantilever and simply supported boundary conditions were included in the analysis and an optimized angular stiffener for a particular swept back panel was achieved. A finite element model for …
Development Of An Optimal Systems Criteria In The Performance Evaluation Of A Crawfish Sorting Machine., Rommel Gaac Tangonan
Development Of An Optimal Systems Criteria In The Performance Evaluation Of A Crawfish Sorting Machine., Rommel Gaac Tangonan
LSU Historical Dissertations and Theses
This study aimed to: (1) establish a set of optimally configured guidelines for performance testing of crawfish sorting machines; (2) examine biophysical characteristics of crawfish and machine-related design parameters; and, (3) write computer programs covering the essential aspects of the crawfish sorting process. Three crawfish sorting machines were tested in the Spring of 1994 and 1995: (1) cylindrical roller sorter machine, (2) diverging vane belt sorter machine, and (3) grid shaker sorter machine. Both the cylindrical roller sorter and the diverging vane belt sorter separated crawfish into four groups: peeler, medium, large and jumbo; the grid shaker sorter, however, separated …
Simultaneous Water-Gas Shift Reaction And Carbon Dioxide Separation For Direct Hydrogen Production From Synthesis Gas., Chun Han
LSU Historical Dissertations and Theses
The simultaneous water-gas shift and CaO-carbonation reactions for the direct hydrogen production from synthesis gas have been studied at high temperature and high pressure using a laboratory-scale fixed-bed reactor. Experiments were conducted to evaluate the effect of process parameters--temperature, pressure, gas composition, and space velocity--on system performance during both calcination and shift/carbonation reaction stages. Commercial dolomite was chosen as the primary sorbent while two limestones were tested for comparison. Multicycle tests were conducted to evaluate sorbent durability. Sorbent structure and structural changes associated with reaction were measured using mercury porosimeter. The experiments proved the technical feasibility of combining the shift …
The Effects Of Shear Stress On The Crystallization Kinetics Of Syndiotactic Polystyrene., Douglas Henry Krzystowczyk
The Effects Of Shear Stress On The Crystallization Kinetics Of Syndiotactic Polystyrene., Douglas Henry Krzystowczyk
LSU Historical Dissertations and Theses
Industrial polymer processes involve the application of heat and stress, often resulting in deformations at high shear rates and molecular orientation. This affects both the crystallization rates and the melting temperature of semi-crystalline polymers. Knowledge of the variance of these properties are vital commercially due to their effect on processing techniques, production rates and mechanical properties. An experimental apparatus was designed and constructed that allowed the study of the effects of shear on syndiotactic polystyrene melt samples. This apparatus consisted of a parallel plate rheometer that used changes in shear stress, as well as infrared detection equipment that utilized changes …
Experimental And Numerical-Modeling Studies Of A Field-Scale Hazardous Waste Rotary Kiln Incinerator., Allen Lee Jakway
Experimental And Numerical-Modeling Studies Of A Field-Scale Hazardous Waste Rotary Kiln Incinerator., Allen Lee Jakway
LSU Historical Dissertations and Theses
A comprehensive study of rotary kiln incineration is ongoing at Louisiana State University. Through experimentation at all levels and numerical modeling, the underlying physical processes are searched out and studied with the intent to improve the understanding of how rotary kiln incinerators process waste with the eventual goal of creating a fully predictive numerical model. The experimental work presented here focuses on mapping combustion gas temperature and, for the first time, velocity fields of a field-scale, industrial incinerator. Measurements are made at multiple points across an upper quadrant of the kiln near its exit using a bidirectional pressure probe, suction …
Remediation Of Contaminated Soils Using A Plant Based Surfactant., Raghava Rao Kommalapati
Remediation Of Contaminated Soils Using A Plant Based Surfactant., Raghava Rao Kommalapati
LSU Historical Dissertations and Theses
A plant based surfactant extracted from fruit pericarps of Sapindus mukurossi (Ritha) is employed for the first time to investigate remediation of contaminated soils. A method for preparing natural surfactant solutions was developed and the solutions were characterized followed by generation and characterization of colloidal gas aphron (CGA) suspensions produced with these solutions. The variation of hexachlorobenzene (HCB) solubility with natural surfactant solutions was estimated and desorption of HCB from soils was investigated with batch and on-dimensional column experiments. Bioenhancement of soil microorganisms in natural surfactant solutions was studied under both aerobic and anaerobic conditions. The empirical formula for natural …
Study Of Two Instrumental Variable Methods For Closed-Loop Multivariable System Identification., Jeannette Santos-Cordero
Study Of Two Instrumental Variable Methods For Closed-Loop Multivariable System Identification., Jeannette Santos-Cordero
LSU Historical Dissertations and Theses
New control strategies are based on the model of the process and it is thus necessary to identify the systems to be controlled. It is also often necessary to identify them during closed-loop operation in order to maintain efficient operation and product quality. Some results of multivariable closed-loop identification carried out on a simulated 2 x 2 linear time-invariant system, using two new versions of instrumental variable methods called IV4D and IV4UP as the identification methods, are presented. In each case pseudorandom binary signals (PRBS), or dithers, are applied to the outputs of the feedback controllers. Algorithms IV4D and IV4UP …
A Study Of The Stress Corrosion Crack Initiation Stage In Alpha-Brass., Kun Lian
A Study Of The Stress Corrosion Crack Initiation Stage In Alpha-Brass., Kun Lian
LSU Historical Dissertations and Theses
The objective of the present work was to provide an insight to the nucleation and evolution of deformation patterns occurring during transgranular stress corrosion cracking (TGSCC) and produce new alternatives for addressing the nature of the embrittlement process. Flat, tensile $\alpha$-brass (72Cu-28Zn) specimens were tested in 5 M NH$\sb4$OH, 0.1 M CuSO$\sb4$ and 1 M NaNO$\sb2$ solutions at a strain rate of $1\times 10\sp{-5}$ s$\sp{-1}.$ Slip band spacing (SBS) and slip band heights (SBH) were measured as a function of strain by conducting interrupted experiments in the SCC environments and were compared with those developed during laboratory air experiments. The …
Elongational Rheometry Of Coextruded Polymer Melts., Ajit Vijay Pendse
Elongational Rheometry Of Coextruded Polymer Melts., Ajit Vijay Pendse
LSU Historical Dissertations and Theses
In most key polymer processing operations such as fiber spinning, blow molding and extrusion through a converging die, the dominant mode of flow is elongational. Rheological characterization of polymeric materials in elongational flow is critical for material quality control as well as for process modeling applications. Unlike shear flows, which have been studied extensively, elongational flows are not well understood, primarily due to the experimental difficulties involved in generating a pure and steady elongational flow field. There is a dearth of commercially available elongational rheometers in the present rheological literature; those that are commercially available, are useful only at elongational …
Use Of A Natural Swamp For Wastewater Treatment., Xiaowei Zhang
Use Of A Natural Swamp For Wastewater Treatment., Xiaowei Zhang
LSU Historical Dissertations and Theses
The purposes of this research were to determine the possibility of using a natural forested swamp for advanced wastewater treatment in coastal Louisiana, and to evaluate the wastewater impact on the ecosystem. The study was performed by comparing two portions of a nutrient deficient swamp separated by a ridge. One portion received secondarily treated municipal wastewater at a rate of $6.3\times10\sp6$ L/day and the other served as a control. Concentrations of BOD$\sb5$, TSS, DO, EC, TDS, pH, N, P, S, CI, K, Ca, Mg, Na and trace metals were monitored. Results showed that the wastewater added nutrients into the swamp. …
Model For Planning Well Control Operations Involving An Induced Fracture., Alvaro Felippe Negrao
Model For Planning Well Control Operations Involving An Induced Fracture., Alvaro Felippe Negrao
LSU Historical Dissertations and Theses
This dissertation presents a numerical simulator for designing a dynamic kill of an underground blowout. The simulator consists of three sub-programs: a reservoir model, a wellbore model, and a fracture model. Previously published procedures have modeled the fracture by assuming a constant pressure in the wellbore at the depth of fracture. This assumption has sometimes led to unrealistic results. In this work, a hydraulic fracture model is coupled with the reservoir and wellbore model using a system analysis approach. The hydraulic fracture model is based on a pseudo-3D model with some modifications introduced to more accurately model the extension of …
A Two Dimensional Vertically Integrated Moving Boundary Hydrodynamic Model In Curvilinear Coordinates., Vibhas Aravamuthan
A Two Dimensional Vertically Integrated Moving Boundary Hydrodynamic Model In Curvilinear Coordinates., Vibhas Aravamuthan
LSU Historical Dissertations and Theses
A two dimensional, vertically averaged, hydrodynamic mathematical model on an adaptive boundary fitted grid is developed. This model addresses numerous drawbacks in the traditional finite difference models and incorporates such features as moving boundaries due to tidal incursion, and the ability to resolve irregular coastline geometries. A semi-implicit finite difference scheme is developed in order to overcome time step restrictions due to the gravity wave stability criterion. An eulerian-lagrangian formulation is used to solve the hydrodynamic equations on unsteady grid systems. The model is applied to study circulation features in Lake Pontchartrain (a medium sized physical system) and to the …
Robust Adaptive Control In H(Infinity)., Gisoon Kim
Robust Adaptive Control In H(Infinity)., Gisoon Kim
LSU Historical Dissertations and Theses
This dissertation addresses the problem of unifying identification and control in the paradigm of ${\cal H}\sb\infty$ to achieve robust adaptive control. To achieve robust adaptive control, we employ the same approach used for identification in ${\cal H}\sb\infty$ and robust control in ${\cal H}\sb\infty.$ In the modeling part, we aim not only to identify the nominal plant, but also to quantify the modeling error in ${\cal H}\sb\infty$ norm. The linear algorithm based on least-squares is used, and the upper bounds for the corresponding modeling error are derived. In the control part, we aim to achieve the performance specification in frequency domain …
Gas Kick Behavior During Bullheading Operations In Vertical Wells., William Leo Koederitz
Gas Kick Behavior During Bullheading Operations In Vertical Wells., William Leo Koederitz
LSU Historical Dissertations and Theses
An experimental study to investigate the bullheading method of well control was performed. The primary focus of the investigation was the downward displacement of gas by liquid, requiring consideration of counter-current flow behavior. Experiments were conducted in a full-scale well, using a computer-controlled downhole fracture simulation system; water and low-viscosity drilling mud were used for bullheading fluids. The results from these experiments provided simple models for the estimation of removal efficiency and maximum pump pressure during bullheading operations. These models are empirical and are limited to conditions within the range of the experimental data. A two-phase flow analysis of the …
Combinatorial Design And Analysis Of Optimal Multiple Bus Systems For Parallel Algorithms., Priyalal D. Kulasinghe
Combinatorial Design And Analysis Of Optimal Multiple Bus Systems For Parallel Algorithms., Priyalal D. Kulasinghe
LSU Historical Dissertations and Theses
This dissertation develops a formal and systematic methodology for designing optimal, synchronous multiple bus systems (MBSs) realizing given (classes of) parallel algorithms. Our approach utilizes graph and group theoretic concepts to develop the necessary model and procedural tools. By partitioning the vertex set of the graphical representation CFG of the algorithm, we extract a set of interconnection functions that represents the interprocessor communication requirement of the algorithm. We prove that the optimal partitioning problem is NP-Hard. However, we show how to obtain polynomial time solutions by exploiting certain regularities present in many well-behaved parallel algorithms. The extracted set of interconnection …