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Multiple Scattering From A Random And Inhomogeneous Slab, Haci-Murat Hubey

Doctoral Dissertations

The reflection and transmission functions of an inhomogeneous slab are calculated by labeling the wave by the number of reflections it has undergone in the medium. The Riccati equation, satisfied by the reflected amplitude, is decomposed into a finite set of linear equations by taking into account the number of scatterings taking place inside the medium and is solved by a novel iterative approach. The order-of-scattering reflection functions method presented here and the coupled integral equation approach of the Bremmer solutions for the internal fluxes are set in a unified frame. The solutions of the Riccati equation are computed numerically …

Predicting The Formation Of Condensation Ash From Coal Combustion, Shu-Mu Hsieh

Doctoral Dissertations

This study predicts the nature of condensation ash formed from direct combustion of coal. Three coal-fire combustors, a cyclone-fired (CF) boiler, a pulverized-fuel (PF) and a drop tube (DT) furnace were considered.

Predictions were based on the hypothesis that condensation ash is formed through two consecutive steps: vaporization and recondensation. Metal-containing species in coal are believed to vaporize during high temperature combustion. These vapors then diffuse and condense at the bulk gas phase.

The amount of metal-related vapor transport to the bulk gas phase is dictated by char surface composition which is, in turn, determined by the temperature history of …

Synthesis And Characterization Of Model Aquatic Particulates For Use In Sorption Studies, Frederick William Page

Doctoral Dissertations

The synthesis and characterization of single- and multi-component model aquatic particulars is the object of this dissertation. Particulates were synthesized from illite, humic and fulvic acids, and iron, aluminum, and manganese hydrous oxides. Characterization included measurement of cation exchange capacity (CEC), and attempts to determine surface area and the pH of zero point of charge. Each of these methods was tested to determine their applicability to aquatic particulates, and attempts were made to improve the methodology.

CEC varied with composition and time of aging. Pure hydrous oxides exhibited decreases in CEC over time. Aging effects were also shown by aluminum …

The Distribution And Survival Of The Genus Propionibacterium In The Estuarine Environment, William Kolanko

Doctoral Dissertations

The Propionibacterium species possess several attributes that would allow them to survive in an estuarine ecosystem. This investigation is concerned with the distribution and survival of the Propionibacterium sp. in the Great Bay Estuary at New Hampshire. To aid in the enumeration of propionibacteria, a selective medium was developed that demonstrated greater than 99.9% selectivity from skin samples. Failure to detect propionibacteria from water, sediment, fish, and shellfish prompted an investigation into factors that may influence survival. Temperature appears to be the major factor affecting the Propionibacterium's ability to establish a niche. An increase in salinity had a stimulatory effect …

Order And Disorder In Early Connecticut: New Haven, 1639-1701, Robert West Roetger

Doctoral Dissertations

This dissertation assesses order and disorder in New Haven, Connecticut from its founding in 1639 to the introduction of Justices of the Peace in 1701. It juxtaposes concepts of the well-ordered society as expressed in puritan rhetoric with the reality of behavior as reflected in legal documents to illustrate the pre-eminent role assumed by law in ordering society. What emerges is a picture of society not rigidly caught up in the policies of perfection, but one characterized by responsive lawmaking, equally flexible enforcement, and reliance upon formal legal institutions to resolve private controversies.

The study begins with a portrait of …

Extensions, Generalizations, Characterizations And Testing For Independence Through Infinite Divisibility, Edward Joul Danial

Doctoral Dissertations

This dissertation investigates various related topics around the exciting concept: "Infinite Divisibility." First, two intricate distributions, namely, the univariate generalized Waring and the hyper-Poisson are proved to be infinitely and noninfinitely divisible, respectively. Analysis and computer approaches are employed. This itself extends the use of some results introduced by Katti, Steutel and Warde. Secondly, generalizations to Warde, Katti and Steutel's sufficient conditions and related results are achieved. Then, numerical application is presented. Thirdly, characterizations through infinite and finite divisibility are obtained. The Poisson, negative binomial, geometric, Bernoulli and uniform c haracterizations in terms of infinite divisibility are deduced. Some of …

Mineralogical, Textural, And Paragenetic Studies Of Selected Ore Deposits Of The Southeast Missouri Lead-Zinc-Copper District And Their Genetic Implications, Kenneth Bruce Horrall

Doctoral Dissertations

“A detailed paragenetic study of Pb-Zn-Cu ores from the Viburnum Number 28, Brushy Creek, and Goose Creek mines in the Southeast Missouri lead district indicates a complicated paragenesis characterized by repeated periods of mineral deposition. The sequence is composed of nineteen minerals including abundant galena, sphalerite, chalcopyrite, pyrite, marcasite, dolomite, calcite, and quartz and minor siegenite, bornite, bravoite, blaubleibender covellite, covellite, gersdorffite, digenite, enargite, tennantite, dickite, and malachite.

The paragenesis indicates that the ore solutions evolved in the following order: (1) Cu-rich, (2) Co-Ni-rich, (3) Pb-Zn-rich, and (4) Fe-rich. Subsequent repeated generations include cubic galena, later sphalerite, and minor crystalline …

Comparative Study Of The Boundary Element Technique And The Finite Element Method In Two Dimensional Eigenvalue Problem, Farough Baradari

Doctoral Dissertations

"In this work we investigate the applicability of a "Boundary Element method 11 for the numerical solution of the Liouville and Helmholtz eigenvalue problem for different two-dimensional geometries including a typical reactor configuration. The method is based on the discretization of the unknown along the boundary and Green's function representation of the governing equation.

To compare the capability of this method with the finite element method, a finite element code which uses quadratic quadrilateral isoperimetric elements was developed. A boundary element code was also written. These codes were used to determine the fundamental eigenvalue for several two-dimensional geometries -- square, …

Gaseous Reactions In Heteroporous Media, Elmer Anthony Klavetter

Doctoral Dissertations

"A modified dusty-gas model which accounts for the effects the pore-size and tortuosity distributions have on the mass fluxes in heteroporous media is presented. The behavior of the dusty-gas model (homoporous model) can be obtained from the modified model when the pressure is either very low or very high as well as for intermediate pressures when the characteristic parameter of the introduced tortuosity function has a very small value. When the pressure is very high or very low, all pores in the porous medium are almost in a single transport regime of either molecular or Knudsen diffusion.

Comparisons of the …

Chemical Corrosion Of Ag Films On Glass, Hyun Soo Park

Doctoral Dissertations

"The chemical corrosion of chemically, vacuum and sputter deposited Ag films on an aluminoborosilicate and a soda lime glass was investigated in wet HCl and saturated water vapor as a function of concentration, temperature and time. The higher corrosion resistance of chemically deposited Ag films in comparison to evaporated or sputtered Ag films is attributed to their lower microvoid density and higher adhesion strength. Ag films on the more chemically durable aluminoborosilicate glass had a higher corrosion resistance. Furthermore, films which received a moderate thermal annealing (80 to 140° C) or were deposited on a glass surface washed with HN0 …

Diffusion Controlled Vinyl Polymerization, Sung Kuk Soh

Doctoral Dissertations

It is well known that the polymerization rate and the molecular weight distribution of vinyl polymers can change markedly during the course of polymerization and that these changes are due to the influence of self-diffusion upon the termination reaction. This phenomenon is commonly referred to as the gel effect and in order to explain the polymerization behavior after the onset of the gel effect, the chain length dependence of the termination reaction should be considered.

A new method of handling polymerization kinetics with the chain length dependence termination reaction is proposed, which is largely independent of the form of the …

An Acoustic Method For Identifying Sand Fabric And Liquefaction Potential, Gene Vincent Roe

Doctoral Dissertations

The testing program described in this dissertation was performed to develop an acoustic method for identifying the fabric of saturated medium to fine sand samples, and their related resistance to liquefaction. Three methods of preparation, that produced repeatably different preferred long grain axis orientations, were used to prepare laboratory samples (6.8" high by 2.7" in diameter) of a uniform, angular sand.

Acoustic signatures were obtained, for both dry and saturated samples, using compressional and shear wave transducers. The latter were developed specifically for the test program and included a 4 bender bimorph array as the shear wave crystal. The samples …

Special Applications Of Irreversible Thermodynamics, Yakov Michael Zilberberg

Doctoral Dissertations

Thermodynamic analysis of various physical phenomena, chemical processes, and industrial installation has become a very important part of engineering work. The evergrowing sophistication of the contemporary technical world has brought about the necessity of extensive developments and applications in the field of Irreversible Thermodynamics which enables one to efficiently treat phenomena that are spatially and temporally non-equilibrium ones, and therefore thermodynamically irreversible. The unavoidable facts that all industrial processes experience randomly distributed external and internal excitations, and also that their variables, being automatically controlled, fluctuate in space in time, require a systematic improvements of the adopted methods of Irreversible Thermodynamic …

Water Quality Impact Of Non-Point Source Contaminants In Small Tidal Rivers, Edward John Schmidt

Doctoral Dissertations

An integrated numerical modeling methodology was developed for analysis of non-point contaminant production and water quality impacts in estuarine receiving waters. The methodology was calibrated against contaminant source observations and estuarine data.

Contaminant source loading is based on the runoff curve number technique combined with a partial contributing area approach. Sediment washoff is used as an indicator of contaminant quantities.

Hydrographs and contaminant load time series are introduced into a set of one-dimensional estuary models. Freshwater flow and tidal height are forcing functions for dynamic computation of velocity and water surface profiles. The effect of longitudinal salinity distribution is included …

How Communication And Confirmatory Strategies Affect The Search For Truth, Michael Ernest Gorman

Doctoral Dissertations

Scientific reasoning has become a topic of recent psychological research. Studies have focused on Karl Popper's idea that scientists should try to falsify, or disconfirm, their hypotheses instead of verifying them. Results indicate that both scientists and college students prefer to use confirmatory logic on simple tasks that model scientific reasoning. The only attempt to instruct subjects to use disconfirmatory reasoning failed (Mynatt, Doherty & Tweney, 1977) though subjects that falsified on their own initiative were more successful than subjects who tried to confirm.

All the studies of scientific reasoning have focused on individuals. But major advances in science are …

An Investigation Of The Nickel-Cobalt Occurrence In The Southeast Missouri Mining District, David Ray Jessey

Doctoral Dissertations

"A study of the occurrence of nickel and cobalt in the Southeast Missouri Mining District has revealed several significant geochemical trends and mineralogical relationships. Regional geochemical studies indicate that the greatest concentration of nickel and cobalt occurs in the Fredericktown area. Mines in the Viburnum Trend also have significant concentrations of these metals. Studies of the Viburnum Trend have established that both nickel and cobalt decrease in concentration southward from the Magmont mine to the Brushy Creek mine, increase at the Fletcher mine, and decrease again at the Sweetwater mine.

A detailed geochemical study of the Buick mine has shown …

Load And Resistance Factor Design Of Cold-Formed Steel Structural Members, Boonsong Supornsilaphachai

Doctoral Dissertations

"In a traditional design, the Allowable Stress method has long been used for the design of cold-formed steel structures. In this design approach, the allowable stress is always used to prevent the possible structural failure by using an appropriate factor of safety selected primarily on the basis of engineering judgment and long-time experience.

Recently, the concepts of risk and reliability analysis have been successfully applied to many fields of engineering. By applying the theories of probability and statistics, the load and resistance design criteria for steel structures have been developed for the design of hot-rolled steel shapes and built-up members. …

A Thermochemical Study Of The Ore Deposits Of The Milliken Mine, New Lead Belt, Missouri, Douglas L. Rickman

Doctoral Dissertations

"The ore body at the Milliken mine is a typical Mississippi Valleytype ore deposit. Mineralization is in a dolostone and structures are subtle, but very important ore controls. The major mineralogy is simple, predominately galena, luminescent hydrothermal dolomite, sphalerite and chalcopyrite. Twenty-three additional minerals have been identified in the ores, including barite and Pb-aragonite, bot h of which have not previously been recognized in the district.

Paragenetically, the ores are very complex, with four major, distinct periods of mineralization plus numerous periods of dissolution. The paragenesis provides evidence for the dynamic, evolving nature of the ore system. Galena textures, euhedral …

The Vertical Structure Of Estuarine Tidal Currents, Ronnal Paul Reichard

Doctoral Dissertations

The surface slope induced pressure gradient, mean current velocity profile, and bottom stress are investigated both theoretically and experimentally for a tidal channel in a well-mixed estuary. The theory focuses on the use of eddy viscosity models. Surface slope estimates based on tide predictions, current velocity profile measurements, and stress estimates from near bottom turbulence measurements are used to investigate the dynamic balance in the tidal channel, and to evaluate the eddy viscosity models. The principal terms in the dynamic balance were found to be the surface slope induced pressure gradient and the bottom stress. The magnitude of the near …

The Construction Of A Logical-Empirical Structure Of Knowledge For Differential Calculus Using A Theoretical Framework Based Upon Learning Hierarchy Theory And Order Theory, James Martin Devecchi

Doctoral Dissertations

The principal result of this study is a logically and empirically valid Structure of Knowledge for Differential Calculus constructed using a methodology based on Learning Hierarchy Theory (LHT) and Order Theory (OT). A review of existing research into calculus learning is presented and properties of the strucutre of knowledge which address deficiencies in existing knowledge discussed. LHT is developed and techniques for the empirical validation and generation of hierarchies are discussed. Included in this discussion is a detailed analysis of the important properties of OT.

The generation of the structure of knowledge consisted of two phases: the logical analysis and …

Phosphate Adsorption And Desorption On Two Contrasting Soils Used For Land Treatment Of Wastewater, Stephen Arthur Gasiorowski

Doctoral Dissertations

Land treatment of wastewater involves the use of plants and the soil to remove unwanted constituents. Removal of phosphorus is particularly important to avoid excessive biological activity in water systems receiving the treated wastewater. This research examines the phosphate adsorption - desorption behavior of two soils: Charlton silt loam, a typical acid soil from New England which is being used in experimental wastewater treatment, and Tujunga coarse sandy loam from a wastewater land treatment facility located at Manteca, California, which has failed to remove phosphate from wastewater efficiently.

The effects of changing the pH and phosphate content of municipal wastewater …

Normal Mode Spectra Of Sound Waves In Viscous Solid And Fluid Media With Particular Applications To Shallow Water Acoustics, Peter Geoffrey Harvey

Doctoral Dissertations

Sound propagation in shallow water is modelled using the Green's function formalism and normal mode techniques. The water layer is bounded above by a pressure-released condition and below by a halfspace of viscoelastic solid media. Nine different marine sediments are investigated by incorporating their published measured parameters into the bottom boundary condition utilizing the definition of specific acoustic impedance. A depth-dependent sound speed is treated in the ideal liquid layer.

In order to determine the most convenient mathematical representation for this shallow water model an investigation of the normal mode spectra of sound waves in viscous fluids and viscoelastic solids …

Interpretation Of Narrow Beam Sonar Echos Using A Variable Impedance Subbottom Model, Robert Leicester Bolus

Doctoral Dissertations

An underwater antenna consisting of an acoustic paraboloid reflector with a 12 kHz transducer mounted at its focus was designed and built for remote sensing of the subbottom {1}. Surveys taken with the 3 degree half-power beamwidth projector operating in a 1/2 ms pulsed mode indicated horizontal and vertical resolutions of less than 1 m with penetration into the sediments of up to 20 m at 20 m of depth. The image detail was substantially increased over that taken with a conventional 30 degree profiler.

The data was interpreted using a physical model of the subbottom consisting of plane parallel …

Thermally Stimulated Polarization And Depolarization Current (Tspc/Tsdc) In Glass, Chi-Ming Hong

Doctoral Dissertations

"The feasibility of studying ionic motion in glass using thermally stimulated polarization (TSPC)/depolarization current (TSDC) techniques was investigated with 4Na₂O·96SiO₂ and 30PbO·70SiO₂ (mol%) glasses. The TSDC peaks in these glasses were dependent on glass composition and attributed to bulk polarization. The high temperature background TSPC is shown to be due to dc conductivity, whereas the TSPC/TSDC peaks in the 4Na₂O glass are attributed to shorter range Na⁺ motion.

The electrical conductivity of glasses determined by TSPC agrees well with that measured by conventional ac or dc techniques. The TSPC technique is a rapid and easy method of measuring the …

An Alternate High Pressure Injection System For Pressurized-Water Reactors, Gary Edward Mueller

Doctoral Dissertations

"To evaluate the In-Core Injection System (ICIS) performance during a loss-of-coolant accident (LOCA) due to a major rupture in the primary system of a pressurized water reactor (PWR), tests were conducted using the thermal-hydraulic computer code RELAP4/MOD5.

The results for the overall plant system show that the maximum core average fuel cladding temperature reached during an intermediate size cold-leg break in a Combustion Engineering PWR with ICIS is equal to the initial operating temperature of 335°c (636°F). The maximum core average fuel cladding temperature reached during a large size cold-leg break with ICIS is 478°c (893°F). This temperature is approximately …

The Effect Of Availability Improvement Of A Nuclear Power Plant On The Cost Of Generating Electricity, Seyyed Mohammad Reza Nejat

Doctoral Dissertations

"The objective of this investigation is to study the economic benefits in operating a nuclear power plant as a result of improving the availability of the secondary (steam) loop of the plant. A new method has been developed to obtain availability, frequency of failure, probability and frequency of operation, cycle time, and uptime for different capacity states of a parallel-series system having components with failure and repair rates distributed exponentially. The method has been applied to different subsystems, systems, and the secondary loop as a whole. The effect of having spare parts for several components, as measured by savings in …

A Molecular Dynamics Study Of The Stability Of Small Prenucleation Water Clusters, Tze-Shan Chen

Doctoral Dissertations

"The dynamical stability and internal energy distribution of prenucleation water embryos have been studied by the molecular dynamic's method. Water clusters containing either five or twenty molecules were chosen to represent prenucleation embryos of small or intermediate size. A central force potential model of water which allows energy to be absorbed into intramolecular modes so that bond lengths and bond angles could adjust to changes in molecular environments was employed to describe the interaction between all pairs of atoms. The motion of the molecules was followed for extended time periods (of the order of several picoseconds) at each of a …

A Development Of Regression Models For Predicting Two-Phase Relative Permeability In Consolidated Rock, Mehdi Honarpour

Doctoral Dissertations

"The primary objective of this study was the development of prediction equations for the water-oil imbibition relative permeability and gas-oil drainage relative permeability from experimental data.

Laboratory relative permeability data along with the corresponding rock and fluid properties were collected, and stepwise linear regression analysis was applied. Relative permeability models were developed in terms of rock and fluid properties.

The prediction models were tested against laboratory values and previously published correlations. It was found that the models developed in this study yield results that are generally in better agreement with experimental values than the previously published correlations"--Abstract p. ii

Analysis And Simulation Of Stepping Motor Systems Using A Phase Plane Approach, Raymond Gerard Gauthier

Doctoral Dissertations

Stepping motors have become an increasingly popular electromechanical interface device, due to their increased reliability and lower costs over the D.C. Servo motor. The inherent open loop mode of stepping motor operation results, under certain circumstances, in a failure mode in which the output of the stepper no longer follows the input commands. In the past, it has been difficult for the designer to define the failure modes and it has not been obvious how to avoid them.

It is the intent of this dissertation to present a mathematical model for a class of stepping motors, the permanent magnet stepping …

Fluctuations And Dissipation In A Thermally Conducting, Viscous, Hydrodynamic Medium, Karl Eric Sundkvist

Doctoral Dissertations

No abstract provided.