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An Experimental Investigation Into Carbon-Dioxide-Induced Organic Deposition., Josh Chia-Hsine Fu
An Experimental Investigation Into Carbon-Dioxide-Induced Organic Deposition., Josh Chia-Hsine Fu
LSU Historical Dissertations and Theses
Wettability change (or a relative permeability effect) has long been considered a mechanism for enhanced oil recovery. Reports show that adsorption of petroleum heavy ends, mainly asphaltenes and resins, onto a rock surface can alter its wettability. Reports also show that high concentrations of CO$\sb2$ will induce the formation of a solid phase in CO$\sb2$/crude mixtures. However, the propensity of a reservoir system for CO$\sb2$-induced hydrocarbon precipitation and how this deposition affects the rock wettability has not been yet investigated. Once variables such as oil composition, pressure, temperature, brine chemistry, and surface mineralogy are adequately defined it becomes possible to …
The Effect Of Microstructure On Constitutive Equations For Metals., Pithuk Keattipun
The Effect Of Microstructure On Constitutive Equations For Metals., Pithuk Keattipun
LSU Historical Dissertations and Theses
A closed-loop system for constant true strain rate test was modified using a Zenith Z-158 microcomputer connected to an optical sensor and MTS tensile testing machine. This new system has several desirable features: (1) the system is easy to operate; (2) the system works with any round shape of ASTM standard specimen; (3) the system works with a constant true strain rate or any form of strain rate; and (4) the system can be controlled to pause or stop at any pre-selected time or amount of true axial strain. Three types of materials, electrical grade iron, austenitic stainless steel, and …
A Numerical Analysis Of Heterojunction Bipolar Devices., Freidoon Mehrad
A Numerical Analysis Of Heterojunction Bipolar Devices., Freidoon Mehrad
LSU Historical Dissertations and Theses
Numerical simulation plays an important role in the design, analysis and fabrication of semiconductor devices. In this work, a computer program is developed to obtain a one-dimensional steady-state constant temperature current-voltage characteristics of diodes and bipolar transistors fabricated from materials having position dependent material properties such as band-gap, electron affinity, permittivity and the density of states functions. The general formulation of the problem allows for an unambiguous choice of reference potential. The modular form of the program allows for the choice of appropriate recombination processes for each of the materials used in the structure. The program can adjust the step …
Three-Dimensional Turbulent Flowfield In A Turbine Stirred Tank., Sheng-Yang Ju
Three-Dimensional Turbulent Flowfield In A Turbine Stirred Tank., Sheng-Yang Ju
LSU Historical Dissertations and Theses
Solutions of conservation equations for the three-dimensional turbulent flowfield in agitated vessels were developed. Results showed that the Navier-Stokes equations with the nonisotropic k-$\varepsilon$ turbulence model described the three-dimensional velocity profiles and turbulence kinetic energy and its dissipation rate for the flowfield. The nonisotropic model considered the rotational effect on turbulence with a turbulent-Richardson-number term and accounted for the important baffling effects through the nonisotropy of the viscosity. The solutions were validated with the experimental data for velocities and turbulence parameters. An isotropic k-$\varepsilon$ turbulence model for rotational flow was also used. This modified isotropic k-$\varepsilon$ model proved to be …
Generation, Migration, And Transportation Of Gas Contaminated Regions Of Drilling Fluid., Vicente Casariego
Generation, Migration, And Transportation Of Gas Contaminated Regions Of Drilling Fluid., Vicente Casariego
LSU Historical Dissertations and Theses
The control of high pressure gas encountered while drilling for hydrocarbon reservoirs is one of the more expensive and potentially dangerous problems of the oil producing industry. When the control of high pressure gas is not accomplished flow of gas from the formation to the wellbore occurs. Once detected, the gas influx is stopped by shutting-in the well. This is the first measure taken in a series of operations which are designed to bring back the well under control. These operations are referred to as well control procedures. Well control simulators are used both for evaluating well control procedures and …
Effects Of Crude Oil Composition And Alcohol Augmentation On Transient Interfacial Phenomena In Alkaline-Water/Crude-Oil Systems., Vivien Johan Cambridge
Effects Of Crude Oil Composition And Alcohol Augmentation On Transient Interfacial Phenomena In Alkaline-Water/Crude-Oil Systems., Vivien Johan Cambridge
LSU Historical Dissertations and Theses
The microscopic phenomena which occur at the alkaline-water/crude-oil interface greatly affect the potential for success of the alkaline water flooding process. The propensity of crude oils to emulsify and the ability of the oil to coalesce improves the chance for successful oil bank formation and leads to better recovery efficiency. Interfacial phenomena are affected by interfacial rheological properties and interfacial tensions. This research investigates the interfacial behavior of alkaline-water/crude-oil systems in three parts. In part one, a new method and apparatus are designed for the measurement of interfacial shear viscosity (IFSV). The method is applied to study the effect of …
Single- And Two-Phase Reacting Flow Predictions---Modeling Of Non-Equilibrium Effects, Turbulent Particle Dispersion And Nitrogen-Oxide Formation In Pulverized Coal Combustion., Dong Soon Jang
LSU Historical Dissertations and Theses
The objective of this dissertation study is to evaluate and improve the modeling of individual processes associated with single- and two-phase turbulent reaction processes. In particular, attention is focused on the pulverized coal combustion process, and a reliable comprehensive computer code for pulverized coal combustion systems is developed to assist in design developments. Primary emphasis in this work has been on the modeling of non-equilibrium turbulent reactions, turbulent particle dispersion, and pollutant species formation. In addition, contributions have been made towards improving the numerical algorithm for pressure-velocity linked system in swirling flows. Two turbulent reaction models are developed for resolving …
Multivariable Control Of Double Effect Heat Integrated Distillation Columns., Shao-Yu Lin
Multivariable Control Of Double Effect Heat Integrated Distillation Columns., Shao-Yu Lin
LSU Historical Dissertations and Theses
The design of a reliable control scheme and efficient computer control algorithm for the double effect heat integrated distillation columns under floating pressure operation to control four product compositions on setpoint specifications has been studied. The system includes a pair of distillation columns with the vapors of one column providing the heat source for the other column. The economic profitabilities of four different configurations of the double effect heat integrated distillation columns for the methanol and water system have been investigated using the ASPEN PLUS process simulation program. Three of the four configurations of the double effect heat integrated columns …
Adaptive Grid Solution Procedure For Elliptic Flows., Fadl Hassan Moukalled
Adaptive Grid Solution Procedure For Elliptic Flows., Fadl Hassan Moukalled
LSU Historical Dissertations and Theses
This thesis deals with the formulation of a computationally efficient adaptive grid system for two-dimensional elliptic flow and heat transfer problems. The formulation is in a curvilinear coordinate system so that flow in irregular geometries can be easily handled. An equal order pressure-velocity scheme is formulated in this thesis to solve the flow equations. An adaptive grid solution procedure is developed in which the grid is automatically refined in regions of high errors and consecutive calculations are performed between the coarse grid and adapted grid regions in the same spirit as that of a Multi-Grid method. In orthogonal coordinate systems, …
Fail-Safe Local Area Networking Using Channel Redundancy., Ibibia Karisemie Dabipi
Fail-Safe Local Area Networking Using Channel Redundancy., Ibibia Karisemie Dabipi
LSU Historical Dissertations and Theses
Local area networks represent a major development in data communications. The ring topology is the most popular of the local area networks. Its inherent problem, however, is the breakdown of the entire network in the event of a station failure resulting in total shut-down until repairs can be made. This dissertation is a study of designs for fail-safe local area networks. Two methods for maintaining the operation of a ring network are analyzed and compared. The first method uses a double-ring where the inner loop is optically coupled to the outer ring whenever a node failure occurs. The analysis performed …
The Rational Overhauser: An Interpolating Rational Cubic Curve., Jeffrey Neil Jortner
The Rational Overhauser: An Interpolating Rational Cubic Curve., Jeffrey Neil Jortner
LSU Historical Dissertations and Theses
A rational interpolating cubic curve which implicitly maintains first order geometric continuity in splines has been developed. The curve is formed by blending two rational quadratic curves. Since the blending method used was originally introduced by Overhauser, this curve is referred to as the Rational Overhauser (Rover) curve. The curve formulation utilizes four shape factors to provide control of the curve. A geometrical and analytical interpretation of these shape factors and their relationship to each other is discussed. Procedures for representing conic sections using the rational Overhauser curve are presented. Also included are techniques for mapping between the Rover curve …
Design And Evaluation Of Gas-Condensate Wells Using The Systems Analysis Approach., David Stephen Sutton
Design And Evaluation Of Gas-Condensate Wells Using The Systems Analysis Approach., David Stephen Sutton
LSU Historical Dissertations and Theses
The use of Systems Analysis for designing and evaluating wells flowing hydrocarbon mixtures seems to create no computational problems when considering the inflow components, i.e. reservoir and perforations. However, when a gas-condensate system is considered, the outflow component calculating the total pressure losses in the tubing creates a computational problem. This computational problem involves the estimation of the phase properties of the gas-condensate fluid. Thus, the fluid system undergoes phase changes as it moves up the tubing. Attempts by other authors have been made to overcome this by either using a single-phase or two-phase flow model. The single-phase flow model …
Classical And Statistical Thermodynamics Of Gas Solubility In Polar Fluids., Christopher Paul Williams
Classical And Statistical Thermodynamics Of Gas Solubility In Polar Fluids., Christopher Paul Williams
LSU Historical Dissertations and Theses
The solubilities of argon and of three binary gas mixtures of nitrogen and methane, 25%CH$\sb 4$ - 75%N$\sb 2$, 50%CH$\sb 4$ - 50%N$\sb 2$ and 75%CH$\sb 4$ - 25%N$\sb 2$, in water have been measured at a temperature of 323K for pressures up to 124.1 MPa. The data have been correlated using the established forms of the Krichevsky-Kasarnovsky and Krichevsky-Ilinskaya equations and are in agreement with previous studies. The performance of the Krichevsky-Ilinskaya equation has been improved by using Wilson's equation in place of the two-suffix Margules equation to predict the non-ideality associated with the solute gas in the solution. …
Use Of Multiple Time Series Analysis To Forecast Maintenance Manhour Requirement For The Chemical Process Industry., Helen Bostock
Use Of Multiple Time Series Analysis To Forecast Maintenance Manhour Requirement For The Chemical Process Industry., Helen Bostock
LSU Historical Dissertations and Theses
It is hypothesized that chemical processing plant maintenance manhour requirement (the number of hours required to maintain a production facility at an optimal level) can be forecast. The hypothesis is supported by (1) a study of the independent variables which may impact the dependent variable, maintenance manhour requirement and (2) a comparative analysis of technological forecasting methods that suggested which methods might be most appropriate. Both econometric and statistical forecasting methods were considered. The philosophy inherent in each approach was recognized. A procedure for choosing a forecasting method to suit a given situation is outlined. Multiple time series analysis, supported …
Vacuum Growth And Characterization Of Thin Films Of Zinc Tin Diphosphide., Hyun Yong Shin
Vacuum Growth And Characterization Of Thin Films Of Zinc Tin Diphosphide., Hyun Yong Shin
LSU Historical Dissertations and Theses
A vacuum growth technique has been employed for the first time to grow thin films of ZnSnP$\sb2$. Near stoichiometric thin films of polycrystalline ZnSnP$\sb2$ have been grown on GaAs and quartz substrates. A reasonable degree of reproducibility of the film composition from one run to the next was achieved by using a quadrupole mass analyzer probe in conjunction with a digital feedback controller to maintain constant Zn flux. The growth parameters for the system including the estimates for the Zn/Sn flux ratio at the substrate and the optimum substrate temperature have been obtained for the near stoichiometric film growth. The …
Borehole Friction Assessment And Application To Oilfield Casing Design In Directional Wells., Eric Edgar Maidla
Borehole Friction Assessment And Application To Oilfield Casing Design In Directional Wells., Eric Edgar Maidla
LSU Historical Dissertations and Theses
The phenomenon of mechanical friction in the oil well borehole was investigated. Immediate application of such a study is to improve casing design in directional wells. An additional application is the prediction of reciprocating loads in directional wells for cementing purposes, that is recognized to be an effective method to avoid cement channeling through efficient mud displacement. Field studies on the borehole friction coefficient revealed its insensitivity to depth, various well trajectories, size of pipe and its surface configuration, leading to the conclusion that one value of the borehole friction factor can represent a single well. Also there was good …
Design Of A Generic Manufacturing Cell Control System., Derya Pamukcu
Design Of A Generic Manufacturing Cell Control System., Derya Pamukcu
LSU Historical Dissertations and Theses
The feasibility of design and demonstration of a cell control system to function in the fully integrated manufacturing environment independent of the parts produced or the manufacturing processes involved was investigated. A hierarchical control structure was used. Free standing implementations of a cell controller, a workstation controller, and programmable device interfaces were designed. The system is data driven, and was designed to use the manufacturing databases that exist in the computer integrated manufacturing environment. Operation of the cell controller and its interaction with the rest of the system was demonstrated in real-time by simulating the computer integrated manufacturing environment on …
An Evaluation Of The Applicability Of Nonlinear Programming Algorithms To A Typical Commercial Process Flowsheeting Simulator. (Volumes I And Ii)., Michael Joseph Richard
An Evaluation Of The Applicability Of Nonlinear Programming Algorithms To A Typical Commercial Process Flowsheeting Simulator. (Volumes I And Ii)., Michael Joseph Richard
LSU Historical Dissertations and Theses
An efficient methodology for using commercial flowsheeting programs with advanced mathematical programming algorithms has been developed for the optimization of operating plants. The methodology was demonstrated and validated using ChemShare Corporation's DESIGN/2000 simulation of the Freeport Chemical Company's plant for sulfuric acid manufacture and three nonlinear programming techniques; successive linear programming, successive quadratic programming and the generalized reduced gradient method. The application of this methodology begins with the development of a feasible base case simulation. Partial derivatives of the economic model and constraint equations are computed using fully converged simulations. This information is used to formulate an optimization problem which …
Computer Simulation Of Hydrostatic Co-Extrusion Of Bimetallic Compounds., Mohammad Mohammad Abadi Dehghani
Computer Simulation Of Hydrostatic Co-Extrusion Of Bimetallic Compounds., Mohammad Mohammad Abadi Dehghani
LSU Historical Dissertations and Theses
A study of hydrostatic co-extrusion of a hard-core/soft-clad bi-metallic compound has been conducted. The research employs the Sachs' boring-out technique to determine the residual stress distribution in a hydrostatically co-extruded copper-clad Gildcop composite. A parallel simulation of the residual stress distribution in such composites extruded to extrusion ratios of 2.25, 4.0, and 7.5 was conducted using the ABAQUS finite element code. The version of the code employed uses an elastic-plastic constitutive law for material behavior and does not simulate deformation heating effects. Data for the mechanical properties were obtained experimentally by constant true strain-rate tests on material identical to that …
Experimental And Finite Element Study Of Residual Stresses In Zircaloy-4(R) And Ofhc Copper Tubes., Jahangir Rasty
Experimental And Finite Element Study Of Residual Stresses In Zircaloy-4(R) And Ofhc Copper Tubes., Jahangir Rasty
LSU Historical Dissertations and Theses
Non-homogeneous plastic deformation associated with metal-forming operations results in a state of residual stress in the final product. Complete evaluation of the mechanical behavior of the product under operating condition requires a knowledge of these stresses. In order to evaluate the magnitude and distribution of residual stresses, existing experimental techniques are complemented by computer-aided simulation of the forming process using elastic-plastic finite element method (FEM). It is found the FEM can be effectively utilized to simulate metal-forming operations in order to determine the combination of process variables which optimizes the residual stress distribution in the final product. In the experimental …
Stability And Stabilization Of The Wave Model., Masoud Shafiee
Stability And Stabilization Of The Wave Model., Masoud Shafiee
LSU Historical Dissertations and Theses
The stability properties of 2-D systems are an important aspect of the design of acoustic, seismic, image and sonar signal processors. This research utilizes the Wave model format to transport 1-D stability techniques to the 2-D setting. The research studies stability through multistep growth bounds on the Wave state. The use of Lyapunov theory is also considered. The research considers also the problem of stabilizing a 2-D system using state and/or output information feedback to interior and/or boundary controls. Finally the problem of observer design for 2-D systems is considered, with the new stability criteria being used to assure observer/system …