Digital Commons Network^™

Numerical Analysis For Blood Distribution In Complete Flow Cross-Section Microvascular Networks, Jewen Xiao

Doctoral Dissertations

As the blood flows through a bifurcation, the axisymmetric red blood cell concentration profile is skewed by plasma skimming. In the downstream segment of the bifurcation the concentration profile of red blood cells recovers symmetry by the red blood cell dispersion process.

In this study, the concentration convective equation, which models the red blood cell dispersion process, is solved with the method of finite differences in cylindrical coordinates. In the computation, a shear-induced diffusivity coefficient is used. The computed hematocrit ratios at the second bifurcation are compared with in vitro experimental data obtained from 50 $\mu$m serial trees with two …

A Micro-Mechanical Fatigue Damage Model For Uni-Directional Metal Matrix Composites., Rainer Echle

LSU Historical Dissertations and Theses

A micro-mechanical damage model for high cycle fatigue loading based on thermo-dynamical principles is developed for uni-directional continuous fiber reinforced metal matrix composites. The model uses a micro-mechanical based theory to predict the fatigue damage evolution in the individual constituents of the composite material, namely the fibers and the matrix, from which the overall fatigue damage evolution in the composite is obtained. The micro-mechanical analysis is performed for each individual constituent using stress and strain concentration tensors based on the Mori-Tanaka method. A fatigue damage criterion based on thermo-dynamical principles is developed and applied to each of the constituents. Fatigue …

Development Of A Prototype Computer-Assisted Well Control System For Deep Ocean Drilling Environments., Orville Allen Kelly

LSU Historical Dissertations and Theses

An advanced prototype computer-assisted deep water drilling well control system was developed using process control technology. The goal of the system was to improve rig safety by reducing the potential for surface and underground blowouts through providing enhanced bottom hole and casing seat pressure control during the well kill process. The system developed is capable of full computer control of the fluid pump and drilling choke control functions during normal well control operations. The system provides computer-assistance in collecting and curve fitting slow circulation rate pump pressure data, in developing a well kill program (kill sheet), and in detecting anomalies …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 13, Number 1, January 1997, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

A twelve page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Removal Of Hydrophobic Organic Compounds And Surfactants From Wastewater: Polyaphron-Enhanced Solvent Extraction And Biodegradation., Chunlong Zhang

LSU Historical Dissertations and Theses

Surfactant based processes are emerging and becoming increasingly important in pollution control. A novel predispersed solvent extraction (PDSE) technique using surfactant based colloidal liquid aphrons (CLAs or polyaphrons) and colloidal gas aphrons (CGAs) for the removal of hydrophobic organic compounds (HOCs) from the aqueous phase was studied. The process involves an extraction of HOCs into CLAs, followed by a flotation using CGAs. Polyaphrons were characterized by a particle size analyzer. The size distribution was found to be bimodal. The effects of surfactant types, surfactant concentrations and storage times on the size distribution were studied. Polyaphrons have long shelf-lives and are …

A Computer Automated, Hydraulically Integrated Serial Turbidostat Algal Reactor (Histar): Mathematical Modeling And Experimental Analysis., Chandra Sekhar Theegala

LSU Historical Dissertations and Theses

Conceptually, the Hydraulically Integrated Serial Turbidostat Algal Reactor (HISTAR) has two components: (1) sealed turbidostats for producing a high quality algal inoculum, and (2) a series of unprotected inter-connected continuous flow stirred tank reactors (CFSTRs) for mass producing algae under approximated plug flow conditions. The hydraulic retention time of each individual CFSTR ($\theta\sb{\rm n})$ is set low enough (dilution is set high) that any suspended organisms (both contaminants and desired algae) entering the CFSTR would be washed to the next CFSTR well within their doubling time. However, as the turbidostats are employed to inoculate the first CFSTR on an almost …

Coastal Restoration Using Pipeline-Conveyed Sediments., Catherine Faith Voisin

LSU Historical Dissertations and Theses

A spreadsheet program was successfully developed which determines the engineering requirements for pipeline transport of sediments from dredge sites to wetland restorations sites. The program called SLURRY.XLS involves several new correlations. A new correlation for determining the critical velocity of particle transport is presented. New correlations were statistically developed for determining the drag coefficient of particles. The spreadsheet also successfully determines settling velocities of the individual particle sizes in any settling regime. A second spreadsheet program entitled "CONSOL.XLS" uses geotechnical principles of consolidation for determining marsh surface elevation with and without hydraulic fill versus time. The CONSOL.XLS program permits the …

Optimization And Scale-Up Of Thiarubrine A Production From Hairy Root Cultures Of Ambrosia Artemisiifolia., Santosh G. Bhagwath

LSU Historical Dissertations and Theses

Thiarubrine A (TA), a plant secondary metabolite synthesized by members of the family Asteraceae possesses antifungal and antiviral properties and is a potential pharmaceutical. The objective of the work was the optimization and scale-up of a bioprocess for the production of TA using hairy root cultures of Ambrosia artemisiifolia. At the inception of the work an established hairy root culture of the model system was used as inoculum in reactor experiments for the development of a protocol for the quantification of TA and in subsequent shake flask experiments to determine optimum culture conditions. TA accumulation closely paralleled growth and then …

An Integrated Gps-Gis Methodology For Performing Travel Time Studies., Cesar A. Quiroga

LSU Historical Dissertations and Theses

This dissertation describes a methodology for conducting travel time studies based on global positioning system (GPS) receivers and geographic information system (GIS) technology. Compared to traditional approaches, the new methodology provides consistency, automation, finer levels of resolution, and better accuracy in measuring travel time and speed. These characteristics enable the detection of localized traffic effects much more efficiently than with traditional techniques. The new methodology automates the data collection and data reduction procedures, and provides improved procedures for documenting and analyzing travel time and speed data. As a result, large amounts of reliable travel time and speed data can be …

Linear Matrix Inequality Approach To Robust Emergency Lateral Control Of A Highway Vehicle With Time-Varying Uncertainties., Robert Edward Benton Jr

LSU Historical Dissertations and Theses

New linear-matrix-inequality (LMI) based methods are developed for the static-output-feedback stabilization and reduced-gain static-output-feedback stabilization of time-invariant systems. Unlike previous methods, the static-output-feedback method is non-iterative in LMI solutions. The methods are extended to design robust static-output-feedback controllers for time-varying systems using a polytopic-systems approach. Examples are given which demonstrate the use of each of the new methods. The specific problem of emergency lateral control of a highway vehicle is then addressed using the new robust static-output-feedback method. A controller is designed which robustly stabilizes the vehicle over the range of highway speeds (15 to 30 m/s) and a range …

Coupled Field Equations For Saturated Soils And Its Application To Piezocone Penetration And Shield Tunneling., Murad Yusuf Abu-Farsakh

LSU Historical Dissertations and Theses

An elasto-plastic coupled system of equations are formulated here in order to describe the time-dependent deformation of saturated cohesive soils. Formulation of these equations is based on the principle of virtual work and the theory of mixtures for inelastic porous media as proposed by Prevost (1980) and Kiousis and Voyiadjis (1988). The saturated soil is considered as a mixture consisting of two deformable media, the solid grains and the water. Each medium is regarded as a continuum and follows its own motion. The coupled equations are developed for large deformations with finite strains in an updated Lagrangian reference frame. The …

Feedback Linearizing Control Strategies For Chemical Engineering Applications., Michael James Kurtz

LSU Historical Dissertations and Theses

Two widely studied control techniques which compensate for process nonlinearities are feedback linearization (FBL) and nonlinear model predictive control (NMPC). Feedback linearization has a low computational requirement but provides no means to explicitly handle constraints which are important in the chemical process industry. Nonlinear model predictive control provides explicit constraint compensation but only at the expense of high computational requirements. Both techniques suffer from the need for full-state feedback and may have high sensitivities to disturbances. The main work of this dissertation is to eliminate some of the disadvantages associated with FBL techniques. The computation time associated with solving a …

Development Of Thin Gold Film Thermal Sensors For Synchrotron X-Ray Exposure Diagnostics., Harish M. Manohara

LSU Historical Dissertations and Theses

High aspect ratio lithography utilizes high intensity exposure sources, such as synchrotron storage rings, to deposit sufficient dose in the resist to produce a successful pattern transfer. Such highly powerful sources are known to cause undesirable thermal effects in the mask-resist-substrate system. Hence, the measurement of temperature of a mask-resist-substrate system during irradiation is an important exposure diagnostic feature. Deposition of a reasonably accurate dose in the resist is controlled by knowledge of the exposure source intensity. Periodic monitoring of the synchrotron radiation beam power and its spatial distribution at the exposure plane is necessary. In this research, diagnostic techniques …

Acid Solubilization Of Fish Protein For Production Of Protein Hydrolysate., Ercument Ozer

LSU Historical Dissertations and Theses

The mechanism of fish protein solubilization by acid hydrolysis at elevated temperatures was investigated. Rate expressions for the solubilization were determined using pilot scale data with two different rate determination methods. A postulated mechanism was verified and estimated rates were evaluated on five independent verification experiments. A functional relationship between nonprotein byproduct concentration and whiteness of fish protein hydrolysate (FPH) was developed. Initial and set-point operating variables were calculated to produce FPH with acceptable color characteristics for food use. A batch reactor was used for duplicate hydrolysis trials conducted at three acid and three temperature levels for four hours. Samples …

Feasibility Study On The Reduction Of Hydrostatic Pressure In A Deep-Water Riser Using A Gas-Lift Method., Clovis Antonio Lopes

LSU Historical Dissertations and Theses

Recent successful exploration efforts in deep waters have heightened interest in developing oil and gas reservoirs on the continental slope. Leases have been obtained in water depths up to 10,000 ft with a requirement that they be drilled within the next decade. Use of current techniques to drill these leases will require extremely large floating drilling units and large diameter marine riser systems. This study presents the results of a feasibility study on the use of an automated gas-lift system for a marine riser that will maintain the hydrostatic pressure in the subsea well-head equal to that of the sea …

A Theory Of Cortical Neural Processing., David Timothy Young

LSU Historical Dissertations and Theses

This dissertation puts forth an original theory of cortical neural processing that is unique in its view of the interplay of chaotic and stable oscillatory neurodynamics and is meant to stimulate new ideas in artificial neural network modeling. Our theory is the first to suggest two new purposes for chaotic neurodynamics: (i) as a natural means of representing the uncertainty in the outcome of performed tasks, such as memory retrieval or classification, and (ii) as an automatic way of producing an economic representation of distributed information. We developed new models, to better understand how the cerebral cortex processes information, which …

Stochastic Techniques For The Solution Of Electrostatic Problems With Applications To Electron Optics., Elias Kougianos

LSU Historical Dissertations and Theses

We apply stochastic techniques towards the solution of the two-dimensional Laplace's equation in boundary value problems encountered in the calculation of electrostatic potentials in electron lenses and deflectors. The justification of these techniques arises from an astonishingly simple but far-reaching principle, which has been known for a long time but has been rarely used: the potential at any point in the interior of a charge-free region can be calculated by performing random walks starting at this point and terminating at the boundary of the region--the potential is then the average of the potential boundary values (assumed known) over the random …

A Study Of The Effect Of Energetic Flux Bombardment On Intensified Plasma-Assisted Processing., Albert Amatey Adjaottor

LSU Historical Dissertations and Theses

An investigation of the plasma nitriding mechanism under intensified conditions (average particle energy up to 1200 eV) was carried out using a triode configuration. The significance of the different physical processes taking place during intensified plasma nitriding, such as sputtering, implantation, defect generation, redeposition and diffusion were investigated experimentally, while theoretical predictions were obtained by using the TRIM (transport of ions in matter) code. A titanium-base alloy was selected as the substrate material. Sputtering yield in an inert atmosphere was found to exhibit three regimes as a function of incoming particle energy. The low energy and high energy regimes were …

Determination Of Hydrocarbon Type From The Dual-Spaced Neutron Tool Responses., Luis Fernando Quintero

LSU Historical Dissertations and Theses

A new interpretation method that allows for the determination of the fluid type present in a formation of interest was developed. The new method is referred to as the "Three Neutron Porosity Log". The method is based on an algorithm that determines three apparent neutron porosities. These porosities, derived from the raw counts of the dual-spaced neutron tool, have three different radii of investigation. All three neutron porosities, near, far, and ratio, when properly calibrated read the true porosity in water-bearing zones. In oil or gas-bearing zones the mud filtrate invasion profile will cause the three apparent neutron porosities to …

Efficient Mapping Of Neural Network Models On A Class Of Parallel Architectures., Behnam Seyed Arad

LSU Historical Dissertations and Theses

This dissertation develops a formal and systematic methodology for efficient mapping of several contemporary artificial neural network (ANN) models on k-ary n-cube parallel architectures (KNC's). We apply the general mapping to several important ANN models including feedforward ANN's trained with backpropagation algorithm, radial basis function networks, cascade correlation learning, and adaptive resonance theory networks. Our approach utilizes a parallel task graph representing concurrent operations of the ANN model during training. The mapping of the ANN is performed in two steps. First, the parallel task graph of the ANN is mapped to a virtual KNC of compatible dimensionality. This involves decomposing …

Cellulose-Reinforced Composites And Srim And Rtm Modeling., Mohammad Fahrurrozi

LSU Historical Dissertations and Theses

Structural reaction injection molding (SRIM) cellulosic/polyurethane composites were prepared from various forms of cellulosic mats, and elastomeric polyurea-urethane (PUU) and rigid polyurethane (PU) formulations. Mats (woven and non-woven) prepared from different sources of fibers with lignin content ranging from zero (cotton) to at least 10% (sugar cane and kenaf fibers) performed comparably in PUU/cellulosic composites. Young's modulus and tensile strength of PUU/cellulosic composites were doubled with 5% and 7% fiber loading respectively. Young's modulus and tensile strength of PU/cellulosic composites were improved by 300% and 30%, respectively, with 7% fiber loading, whereas their bending moduli and strengths were improved up …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 12, Number 10, December 1996, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

A twelve page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 12, Number 9, November 1996, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

A ten page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 12, Number 8, October 1996, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

A ten page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 12, Number 7, September 1996, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

An eight page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 12, Number 6, June 1996, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

A ten page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 12, Number 5, May 1996, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

An eight page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 12, Number 4, April 1996, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

A six page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 12, Number 3, March 1996, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

A ten page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 12, Number 2, February 1996, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

A fourteen page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.