Digital Commons Network^™

The Utilization Of Municipal Solid Waste Combustion Bottom Ash As A Paving Material, Xishun Zhang

Doctoral Dissertations

A research project was conducted to investigate the potentials of using municipal solid waste combustion bottom ash as a paving material. The effort focused on (i) characterization of the time-dependent properties of the bottom ash, (ii) bottom ash utilization as an unbound material in road subbase and base application, and (iii) bottom ash utilization as an aggregate substitution in hot mixture asphalt. A series of standard or non-standard procedures were employed to evaluate bottom ash behavior.

Results indicate that variability of the physical properties of the bottom ash produced during the two years study period is relatively small in view …

Theoretical And Experimental Modeling Of Removing Contaminants From Soils By An Electric Field., Akram Nimer Alshawabkeh

LSU Historical Dissertations and Theses

A mathematical model is formulated for multicomponent transport of reactive species under an electric field. A set on differential and algebraic equations is developed for transport of fluid, charge, and species in a saturated soil under coupled hydraulic, electric, and chemical potential gradients. An iterative scheme is chosen in solution of a system of differential and algebraic equations. Six differential equations and four algebraic equations are used to model transport of $Pb\sp{2+}$, $H\sp+$, $OH\sp-$, $NO3\sp-$, the associated chemical reactions, electric potential and the hydraulic head across the electrodes. Finite Element Method is used in space discretization. Finite difference technique is …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 10, Number 1, January 1994, 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.

Modeling Transport Of Non Aqueous Wastes In Unsaturated Soils., Dharmesh Vinaychandra Doshi

LSU Historical Dissertations and Theses

In evaluating risks associated with chemical spills on the ground surface or leaks from underground storage tanks, it is required to know the extent and degree of contamination in the subsurface. In many cases pure organics are spilled and due to their low miscibility with water they remain pure or concentrated for some distance or time from the source. This dissertation is aimed at developing a model of the multiphase (air, water, organic) migration processes. The particular focus is on modeling organic infiltration in the unsaturated zone where the transport is largely vertical. Sand-column experiments using a variety of immiscible …

Biochemical Oxygen Demand Removal Reaction Rate Constants In Microbial Rock Plant Filter Treatment Systems., Bhaskar Kura

LSU Historical Dissertations and Theses

Microbial Rock Plant Filters (MRPFs) are capable of treating municipal wastewaters, particularly for the removal of biochemical oxygen demand (BOD) in an economic manner. There is no consensus on proper design for these treatment systems due to the limited performance data available on these recently developed systems (Reed, 1993). Variability of the BOD removal reaction rate constant is an important observation which has bearing on the design of these systems. Variability of BOD removal reaction rate constant along the filter length was modeled as a function of the variable microbial activity. The microbial activity was estimated using a modified fluorescein …

Studies On The Diffusive Transport Of Hydrophobic Organic Chemicals In Bed Sediments., Gregory John Thoma

LSU Historical Dissertations and Theses

Hydrophobic chemicals have accumulated in sediments for most of the last century as the result of industrial and municipal discharges as well as urban and agricultural runoff to surface waters. Beginning with the Clean Water Act, these pollutant sources have been significantly reduced resulting in the sediments becoming a source of pollutants to the overlying water ecosystem. It is therefore important to determine the rate at which the contaminants associated with the sediment are released to the water. Removal or isolation of sediment-associated contaminants is often desirable. One option for isolation of contaminated sediments from the aquatic ecosystem is capping, …

The Studies Of Rigid Pvc Compounds: Morphology, Rheology, And Fusion Mechanism., Cheng-Ho Chen

LSU Historical Dissertations and Theses

Morphological analyses of PVC, PVC/CPE, and PVC/CPE/OPE compounds were examined by scanning electron microscopy, transmission electron microscopy, and scanning-transmission electron microscopy. A correlation has also been established between the morphological analyses and the IZOD impact strength of PVC compounds. PVC compounds were prepared in a Haake Torque Rheometer using various blending conditions. The fusion level of processed compounds was evaluated by DSC thermal analysis and capillary rheological analysis, based on the heat of fusion and entrance pressure drop, respectively. S-shaped fusion curves were obtained. The effects of temperature, rotor speed, and totalized torque on the fusion level of PVC compounds …

The Development Of Bridge Inspection Strategies Based On A Statistical Analysis Of Deterioration In Underwater Structures., Mark Deymond Fugler

LSU Historical Dissertations and Theses

A comprehensive statistical analysis was performed on the condition data generated by a statewide underwater inspection of bridges in Louisiana. The research defined pertinent underwater structural decay characteristics and established a method for establishing a bridge's propensity for underwater deterioration based upon those relevant factors. The inspection results were reviewed to ascertain the impact of human-bias on the consistency in the bridge condition ratings. Using a set of importance factors obtained through a questionnaire submitted to a group of inspectors, the fuzzy set theory was employed to assist in the removal of data incongruities. A combination of pure fuzzy set …

Finite Element Analysis Of Damage And Elastic-Plastic Behavior Of Metal Matrix Composites., Taehyo Park

LSU Historical Dissertations and Theses

Damage and elasto-plastic analysis is of particular importance to metal matrix composites since the onset of damage and plastic yielding begins very early in the loading process as compared to the composites ultimate strength. Two types of damage models are proposed using micromechanical model. A finite element analysis is presented for quantifying damage and predicting the failure loads of the center-cracked laminate metal matrix composite plates. Both the overall damage model which accounts for all types of damages as a single damage variable and the local damage model which uses the local constitutive damage relations for each of the matrix …

Second Order Neural Networks., Sanjoy Das

LSU Historical Dissertations and Theses

In this dissertation, a feedback neural network model has been proposed. This network uses a second order method of convergence based on the Newton-Raphson method. This neural network has both discrete as well as continuous versions. When used as an associative memory, the proposed model has been called the polynomial neural network (PNN). The memories of this network can be located anywhere in an n dimensional space rather than being confined to the corners of the latter. A method for storing memories has been proposed. This is a single step method unlike the currently known computationally intensive iterative methods. An …

Traction And Agricultural Tractor Tire Selection Studies., Francois Pascal Brassart

LSU Historical Dissertations and Theses

A machine was built to study non-rolling tire stiffness and damping coefficients of agricultural tractor tires in the vertical direction. Static deflection on a rigid surface was measured as a function of vertical load. During dynamic experiments, a sinusoidal forcing function was imposed on the test tire to determine dynamic stiffness and damping coefficient from load and deflection measurements. The experimental setup and methodology are described. Ten tires were tested. Both static and dynamic stiffnesses appeared linearly related to inflation pressure. No correlation was found between dynamic properties and excitation frequency. Comparisons among stiffness and damping coefficient values were made …

A Study Of The Radiative Properties Of Agglomerated Flame Particulates Using Light Scattering., Demetris Theodosios Venizelos

LSU Historical Dissertations and Theses

The in-situ optical technique of inferring the soot agglomerate structural and optical properties from the measurements of the extinction cross section, the differential scattering cross section, the dissymmetry ratios in both planes of polarization, and the depolarization ratio, was investigated in detail by this study. A sensitivity analysis of the technique revealed that the dissymmetry ratios are insensitive to both the real and imaginary part of the refractive index. The ratio of the differential scattering to extinction cross sections was also found to be a weak function of the imaginary part of the refractive index. The sensitivity analysis results indicate …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 9, Number 10, December 1993, 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 9, Number 9, November 1993, 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.

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 9, Number 8, October 1993, 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 9, Number 7, September 1993, 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 9, Number 6, June 1993, 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 9, Number 5, May 1993, 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 9, Number 4, April 1993, 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 9, Number 3, March 1993, 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 9, Number 2, February 1993, 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.

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 9, Number 1, January 1993, 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.

Catalytic Cracking Of Hydrocarbons With Novel Metal Traps, Hany Iskandar Farag

Digitized Theses

Nickel and vanadium poison FCC catalysts with destruction of zeolites. This is reflected by a lower gas oil conversion and lower gasoline selectivity. Ni and V also affect hydrogen transfer resulting in more coke formation and reducing light gases.;New catalysts, so-called FCCT (catalysts for FCC with "in situ metal traps"), were developed in this study to achieve high dispersion of passivators. FCCTs were extensively tested and demonstrated experimentally. On the strength of these results, it can be stated that high dispersion of the metal traps, using the "in situ" mode of preparation with traps "waiting" the contaminants and "shielding" the …

Multibond Graph Method For Flexible Multibody System Dynamics, Simon Xun-Nan He

Digitized Theses

In this thesis, a general method for the modelling and simulation of the dynamics of flexible multibody systems undergoing special motion is developed using the multiband graph approach. Until now, bond graph was mostly used to model rigid multibody system dynamics and two dimensional flexible bodies. The multibond graph approach developed in this thesis for the computer-aided modelling and simulation of flexible multibody system dynamics provides an alternative to current computer-aided modelling and simulation of 3-D flexible multibody system dynamics with the added advantage of including a mixed energy domain. The flexible multibody system considered consists of a number of …

Fluid Dynamics Of High-Temperature Bubble And Slurry Bubble Columns, Julie Chabot

Digitized Theses

The present Ph.D. dissertation was focused on the study of the fluid dynamics of high temperature bubble and slurry bubble columns. The study was centred on a system of particular interest for the petrochemical industry, the liquid phase methanol synthesis process, for which very little information is currently available. Emphasis was placed on the study of important gas phase parameters, including the gas holdup, the bubble rise velocity, the bubble chord length and the bubble chord length distribution, which were measured using spherical bulb fibre optic sensors.;The experiments were conducted in a 0.2 m diameter and 2.4 m height carbon …

Hydrodynamic Studies Of The Flow Of Fine Particles Through A Fluidized Dense Bed Of Coarse Solids, Jaideep Talukdar

Doctoral Dissertations

This study explains the hydrodynamics of a circulating fluidized bed (CFB) system, the Battelle Multi-Solids Fluidized Bed System (MSFB). It consists of a circulating fluidized bed of fine particles superimposed on a bubbling bed of coarse solids.

One way to characterize such a system is to describe the mechanism of gas-solid flow through the bed. The gas flow in systems like these is through bubbles or slugs (regions of voids containing little or no solids). Bubbles are typically characterized by their size (length or diameter), their rise velocity, and their frequency.

Another task of the initial phase of this study …

Automatic Tool Path Generation For Numerically Controlled Machining Of Sculptured Surfaces, Xiaoxia Li

Doctoral Dissertations

This dissertation presents four new tool path generation approaches for numerically controlled machining of sculptured surfaces: TRI$\sb-$XYINDEX, FINISH, FIVEX$\sb-$INDEX, FIX$\sb-$AXIS$\sb-$INDEX. All of the above systems index the tool across the object surface in the Cartesian space so that evenly distributed tool paths are accomplished.

TRI$\sb-$XYINDEX is a three-axis tool path generation system which uses a surface triangle set (STS) representation of the surface for tool position calculations. Surface edges are detected with local searching algorithms. Quick tool positioning is achieved by selecting candidate elements of polygons. Test results show that TRI$\sb-$XYINDEX is more efficient when machining surfaces which are relatively …

A Computer Model Of The Role Of Text Integration In The Solution Of Arithmetic Word Problems, Mark David Leblanc

Doctoral Dissertations

Understanding arithmetic word problems involves a complex interaction of text comprehension and mathematical processes. This work presents a computer model of the hypothesized processes that are required of a young student solving arithmetic word problems, including the processes of sentence-level leading and text integration. Unlike previous computer simulations of word problem solving, which neglect the early stages of text processing, this model forces a detailed consideration of the linguistic process, which is being increasingly recognized as a primary source of difficulty. Three experiments were conducted to isolate critical test comprehension processes. Children's probability of solution was analyzed in regression analyses …

Rapid Hydropyrolysis Of Coals For Production Of Liquid Hydrocarbons, Abdul Rahman Mohamed

Doctoral Dissertations

Production of fuels and chemicals from coal is becoming attractive due to potential high cost and uncertain supply of crude petroleum oil. Conventional techniques of coal liquefaction, though technically feasible, have been expensive due to hydrogen requirements, high pressure equipment, and high cost of commercial supported catalysts.

In this study, a novel technique for rapid hydropyrolysis of bituminous, subbituminous, and lignite coals has been investigated. Rapid hydropyrolysis is the process of heating at a fast rate to high temperature in a hydrogen environment. A coal sample in hydrogen atmosphere is targeted, in the absence of a catalyst, with a high …

Fiber-Reinforced Plastic Grids For The Structural Reinforcement Of Concrete Beams, Joseph Robert Yost

Doctoral Dissertations

The research presented in this dissertation evaluates the performance of simply supported concrete beams reinforced with a 2 dimensional Fiber Reinforced Plastic (FRP) grid. The non-corrosive, high strength properties characteristic of FRP materials make them a desirable structural reinforcement for concrete in environments where high concentrations of chloride ions are present.

The FRP grid under investigation is called NEFMAC and it is manufactured by Turay Industries of Tokyo Japan. NEFMAC is dimensionally fabricated as orthogonally intersecting longitudinal and transverse bars. The bars are continuous at the intersection points and, as such, there exists no preferred or strong direction within the …