Digital Commons Network^™

A High -Order Finite Difference Method For Solving Bioheat Transfer Equations In Three-Dimensional Triple -Layered Skin Structure, Haofeng Yu

Doctoral Dissertations

Investigations on instantaneous skin burns are useful for an accurate assessment of burn-evaluation and for establishing thermal protections for various purposes. Meanwhile, hyperthermia with radiation is important in the treatment of cancer, and it is essential for developers and users of hyperthermia systems to predict, and interpret correctly the biomass thermal and vascular response to heating. In this dissertation, we employ the well-known Pennes' bioheat transfer equation to predict the degree of skin burn and the temperature distribution in hyperthermia cancer treatment.

A fourth-order compact finite difference scheme is developed to solve Pennes' bioheat transfer equation in a three-dimensional single …

Modeling Of Solid Layer Growth At A Constant Speed In A Binary Melt Crystallization Process, Zongwen Feng

Doctoral Dissertations

Melt crystallization is an attractive separation method for the purification of organics at a large scale. Because the geometry of the rigid crystal lattice is peculiar to the particular substance, most crystallization processes form eutectic systems. The kinetics of crystallization limit the rate in which crystal growth can occur without the incorporation of undesired impurity. If the rate of heat transfer exceeds the mass transfer rate of the impurity, the impurity can solidify, contaminating the product. In practice, one would like to specify a crystallization rate and determine the temperature profile of the crystallizer wall that would achieve this rate. …

The Logic Of Pre-Electoral Coalition Formation, Sona Nadenichek Golder '89

Doctoral Dissertations

Political parties who wish to exercise executive power are typically forced to enter some form of coalition. Parties can either form a pre-electoral coalition prior to an election or they can compete independently and enter a government coalition afterwards. Although there is a vast coalition literature, there are no theoretical or empirical studies of coalitions that form prior to an election. This dissertation seeks to redress this imbalance in our knowledge of coalitions by explaining the variation in electoral coalition formation.

The existing literature implicitly suggests that pre-electoral coalition formation is a simple function of electoral rules: the more disproportional …

Mathematical And Empirical Modeling Of Chemical Reactions In A Microreactor, Jing Hu

Doctoral Dissertations

This dissertation is concerned with mathematical and empirical modeling to simulate three important chemical reactions (cyclohexene hydrogenation and dehydrogenation, preferential oxidation of carbon monoxide, and the Fischer-Tropsch (F-T) synthesis in a microreaction system.

Empirical modeling and optimization techniques based on experimental design (Central Composite Design (CCD)) and response surface methodology were applied to these three chemical reactions. Regression models were built, and the operating conditions (such as temperature, the ratio of the reactants, and total flow rate) which maximize reactant conversion and product selectivity were determined for each reaction.

A probability model for predicting the probability that a certain species …

Can Fundamental Value Predict Stock Returns? An Empirical Assessment Of The Feltham -Ohlson Model, Colin Anthony Pillay

Doctoral Dissertations

In valuation research, two modeling approaches that have become prominent are those based on the Residual Income Model (RIM) and those based on the G. Feltham-James A. Ohlson framework. Ohlson (1995) develops a valuation model which links a firm's fundamental value to the book value of equity, earnings and other relevant information. Feltham and Ohlson (1995) extend the Ohlson (1995) model to incorporate growth and conservative accounting.

This study provides an evaluation of the Feltham-Ohlson (1995) model assuming market inefficiency. Analyst forecast data are obtained from the international I/B/E/S files. Financial information and share prices are obtained from the Compustat …

Head Losses Occurring Through Smooth Pipe Fittings, Liner Folds And Fusion Joints, Ellis Dale Hart

Doctoral Dissertations

This dissertation has involved laboratory and analytical studies of pipe head losses which were caused by: (a) smooth wye and tee fittings of 4-inch and 6-inch diameter with corresponding 4-inch and 6-inch laterals, (b) pipe liner folds created by inadequate stretching of the liner during placement, and (c) fusion joints which protrude a short distance into the pipe causing a small but unknown head loss. Though the individual loss was found to be small, cumulative losses could prove worthy of design consideration.

The velocity and head loss measurements were made using either a 4-inch or 6-inch model diameter pipe. Having …

Faculty And Teacher Candidate Computer Self -Efficacy And The Relationship Of Faculty Computer Self -Efficacy, Technology Professional Development, And Technology Use, Rebecca A. Callaway

Doctoral Dissertations

The purpose of this study was to examine the possible relationship among faculty computer self-efficacy, technology professional development, and the extent of technology use in Louisiana's college and university classrooms. Additionally, faculty computer self-efficacy and teacher candidate computer self-efficacy were compared.

Participation was voluntary, involving higher education faculty and teacher candidates from the nineteen teacher preparation institutions within Louisiana. Faculty completed online surveys. A 30-item Likert-type scale was used to measure computer self-efficacy. Faculty also reported their involvement in technology training over the last five years and their technology use in the classroom. Teacher candidates completed either an online or …

A Numerical Method To Solve The Two-Step Parabolic Heat Transport Equations In A Microsphere Subjected To An Ultrafast Laser Pulse, Ibrahima Khalil Fiman Kaba

Doctoral Dissertations

Heat transport at the microscale is the subject of intense investigation due to the growing need to fabricate microstructures for applications in nanotechnology. The need to control the spread of the thermal process zone has led to the development of high power short-pulse lasers. During thermal processing, impurities may form in the material. An amplification of the thermal energy around the impurities may result in severe damage occurring or in the failure of the thermal process. A thorough analysis of the way the impurities dissipates the thermal energy is therefore necessary to minimize the potential damage and optimize the thermal …

Transformational Leadership, Perceived Union Support, And Union Citizenship Behaviors: A Social Exchange And Social Identity Perspective, Nicholas William Twigg Jr.

Doctoral Dissertations

The objective of this dissertation is to empirically assess the relationship between transformational leadership and union citizenship behaviors from a social exchange and social identity perspective. The relationship was studied through a covenantal relationship perspective. Podsakoff, MacKenzie, Paine, and Bachrach (2000) suggested that there were conceptual similarities and differences in the relationships between transformational leadership, perceived organizational support, trust, intrinsic satisfaction, and commitment in an organizational citizenship behavior framework. This dissertation has developed and tested a model that provides a framework to describe the mechanism by which transformational leadership behaviors effect union citizenship behaviors through perceived union support, felt obligation, …

Free Products Of Operator Spaces And Free Markov Processes, Mingchu Gao

Doctoral Dissertations

Certain (reduced) free product is introduced in the framework of operator spaces. Under the construction, the free product of preduals of von Neumann algebras agrees with the predual of the free product of von Neumann algebras. This answers a question asked by Effros affirmatively. An example is presented to show that the C*-algebra reduced free product of two C*-algebras may be contractively isomorphic to a proper subspace of the operator space reduced free product of the two C*-algebras.

Free Markov processes are also investigated in Voiculescu's free probability theory. This highly non-commutative notion generalizes that of free Brownian motion and …

Multiple Steady Solutions And Bifurcations In The Symmetric Driven Cavity, Kahar Bin Osman

Doctoral Dissertations

The symmetric driven cavity with sinusoidal forcing for two- and three-dimensions is considered. Results are obtained via numerical computations of the Navier Stokes equations with constant density. The numerical integration is a splitting method, using the Crank-Nicholson method for linear terms and the second-order Adams-Bashforth method for the non-linear terms. Spatial derivatives are evaluated with finite differences, and matrix equations are treated with SOR by lines. The results show symmetric solutions for low Reynolds numbers and asymmetric solutions for higher Reynolds numbers. Subcritical bifurcations are observed for two-dimensional flow. Unsteady flow behavior occurs at higher Reynolds number. Three-dimensional simulations for …

Effective Elastic Properties Of Two -Dimensional Solids With Inhomogeneities Of Irregular Shapes, Jindrich Novak

Doctoral Dissertations

This work investigates the effective elastic properties of two-dimensional solids with inhomogeneities of various shapes. We develop a special procedure to evaluate the contribution of irregularly shaped inhomogeneities to these properties. The method can also be used to investigate the stress concentrations around the inhomogeneities. The procedure is based on the analysis of a representative volume element. We express the contribution of each inhomogeneity to the overall moduli of the composite in terms of the compliance contribution tensor. To calculate the components of this tensor, we devise a method that combines analytical and numerical approaches: Kolosov-Muskhelishvili complex variable technique and …

Perceptions Of Eighth-Grade Mathematics Teachers Of The Impact Of The Maine Educational Assessment On Instructional Practices, Mary Christine Runge

Doctoral Dissertations

The purposes of this study are (a) to examine the perceptions of eighth grade mathematics teachers in the state of Maine concerning their classroom instructional and assessment practices and the influence on their students' scores in the MEA tests and (b) to determine if there is a relationship between community social/economic levels and student achievement on the Maine Educational Assessment (MEA) mathematics tests. The survey instrument consisting of a mailed questionnaire designed for this study contained 86 Likert scale items that measured teachers' beliefs regarding the following resource 1 indicators: awareness and use of MEA resources, content area knowledge, instructional …

Shifting Worlds: Leading Educational *Change In A Quantum Universe, Mary O Douglas Singer

Doctoral Dissertations

The twentieth century theories of quantum physics and chaos theory in mathematics have had an impact across disciplines, but in many ways educational leaders have been trapped in the old Newtonian paradigm. The conceptual portion of this study bridges the paradigms to suggest new ways to view school leadership for the twenty-first century, using New Science constructs, systems thinking, and leadership concepts of business writers Senge (1990) and Wheatley (1992). It argues that such business models are appropriate for school organizations, and builds a conceptual model of a quantum principal who may participate in creating change through transformation (Burns, 1978) …

Fire Dynamics In Amazonia, Manoel Cardoso

Doctoral Dissertations

Fires are major disturbances for ecosystems in Amazonia. Because of their short time scale and strong links to biogeochemical cycles, fires significantly affect fluxes and stocks of carbon and nutrients, change air composition, and modify ecosystems structure and functioning. Fires are strongly related to land-use, land-cover and climate conditions. Because the increasing development of the region, these factors have been changing and leading to different patterns of fire activity. Thus it is very important to understand the dynamics of fires in the region and to develop models that can project their potential changes. To contribute in all these subjects, we …

Ocean Color Modeling: Parameterization And Interpretation, Hui Feng

Doctoral Dissertations

The ocean color as observed near the water surface is determined mainly by dissolved and particulate substances, known as "optically-active constituents," in the upper water column. The goal of ocean color modeling is to interpret an ocean color spectrum quantitatively to estimate the suite of optically-active constituents near the surface. In recent years, ocean color modeling efforts have been centering upon three major optically-active constituents: chlorophyll concentration, colored dissolved organic matter, and scattering particulates. Many challenges are still being faced in this arena. This thesis generally addresses and deals with some critical issues in ocean color modeling.

In chapter one, …

Mental Accounting Psychology And Life Cycle Economics: Who Saves, Who Doesn't And How To Tell The Difference, Thomas James Van De Water Iv.

Doctoral Dissertations

Wealth is often associated with status purchases or belonging to a demographic group instead of a cognitive decision process for saving and accumulating wealth. Mental accounting psychology (Kahneman & Tversky, 1979; Shefrin & Thaler, 1988) and life cycle economics (Modigliani & Brumberg, 1954) describe two different saving processes. Qualitative interviews in Study 1 (adult heads of household, n = 24) and a quantitative analysis in Study 2 (2001 Survey of Consumer Finances, n = 4,332) compared high and low saving people using mental accounting and life cycle variables. Interviews in Study 1 predominantly described saving in terms of short-term, mental …

Contributions To Predicting Contaminant Leaching From Secondary Materials Used In Roads, Defne S. Apul

Doctoral Dissertations

Slags, coal ashes, and other secondary materials can be used in road construction. Both traditional and secondary materials used in roads may contain contaminants that may leach and pollute the groundwater. The goal of this research was to further the understanding of leaching and transport of contaminants from pavement materials. Towards this goal, a new probabilistic framework was introduced which provided a structured guidance for selecting the appropriate model, incorporating uncertainty, variability, and expert opinion, and interpreting results for decision making. In addition to the framework, specific contributions were made in pavement and embankment hydrology and reactive transport, Bayesian statistics, …

Granite: A Scientific Database Model And Implementation, Philip J. Rhodes

Doctoral Dissertations

The principal goal of this research was to develop a formal comprehensive model for representing highly complex scientific data. An effective model should provide a conceptually uniform way to represent data and it should serve as a framework for the implementation of an efficient and easy-to-use software environment that implements the model. The dissertation work presented here describes such a model and its contributions to the field of scientific databases. In particular, the Granite model encompasses a wide variety of datatypes used across many disciplines of science and engineering today. It is unique in that it defines dataset geometry and …

Study Of The Enhancement Effect Of Cyclopentadecanolide On Protein Permeation Through Lipid Membranes, Zhengmao Li

Doctoral Dissertations

Intranasal drug delivery has been a topic of increasing interest for a decade as a convenient and reliable method for the systemic administration of drugs. The low bioavailability of simple formulation of protein drugs, such as insulin, can be greatly improved by using permeation enhancers. We studied the effect of cyclopentadecanolide (CPE-215RTM) as a permeation enhancer in protein release through lipid bilayer membranes. We successfully designed a novel in-vitro membrane permeability model using liposomes and performed a series of transmembrane protein release experiments. These were carried out under a wide range of conditions in the presence of different permeation enhancer …

Development Of Muscle Structure And Function In Loliginid Squids, Gabriela Maria Martinez

Doctoral Dissertations

Squid embryos are able to contract their mantle early during the embryonic period.

This dissertation examines the onset of contractile capabilities and subsequent maturation of the main locornotor structures in embryos of two species of loligind squids with a focus on the mantle musculature. The functional implications of the differentiation and organization of the musculature is investigated.

The results of these series of studies indicate that the development and emergence of functional competence of the mantle musculature in loliginid squids is a dynamic process. Differentiation and organization of the musculature of the main locomotor structures does not occur simultaneously and …

Spectral Interpretation Of Zeros Of Zeta Functions, Tamas Waldhauser

Doctoral Dissertations

For every algebraic number field we construct an operator on a separable Hilbert space, whose eigenvalues are exactly the critical zeros of the Dedekind zeta function of the number field.

On The Rayleigh -Brillouin Scattering In Air, Qiuhua Zheng

Doctoral Dissertations

GroundWinds lidar system is a high-spectral-resolution lidar system that can directly measure the Rayleigh-Brillouin scattering (RBS) spectra, from which the wind, temperature, and turbulence in the troposphere can be measured. Its transmitter is a double-frequency Nd-YAG laser at 532nm. Most of the data used in this research were taken on 31 July 2002.

A widely used mathematic model---the S6 model---is fitted to the measured RBS spectra. The discrepancies between the measured temperature from the RayleighBrillouin spectra and from the radiosonde, combined with the discrepancies between the model and the measured RBS spectra, indicate that there is room for the S6 …

The Role -Taking Experience Of Undergraduate Peer Tutors: A Cognitive -Developmental Approach, Margaret Coulthard Pobywajlo

Doctoral Dissertations

The two purposes of this study were (1) to investigate the effects on undergraduate peer tutors of taking on the role as tutors (2) to explore what happens in tutors' experience to impact growth. Three research questions investigated changes in tutors' cognitive-structural development, the complexity of their thinking about tutoring, and tutoring practice. The fourth question investigated the mechanisms of change. This study addresses the lack of research about undergraduate college tutors and the ways in which they change as a result of taking on the tutoring role.

The participants were nine undergraduate peer tutors at an urban commuter college …

The Interplay Between Instructional Policy And Its Constituents: How Mathematics Teachers Interact With And Understand "Principles And Standards For School Mathematics", Dawn M. Berk

Doctoral Dissertations

Educational policies aimed at reforming school mathematics education have been disseminated at an increasing rate in recent years. The impact of such policies hinges on if and how constituents decide to implement the policy recommendations, and these decisions depend largely on constituents' interpretations of the policy. Investigating how classroom teachers make sense of policy recommendations is particularly important, for teachers are the ones who ultimately decide what mathematics students learn, and how they learn it. This research followed a group of teachers as they studied a particular instructional policy, Principles and Standards for School Mathematics (NCTM, 2000). Fourteen middle school …

Chemical Heterogeneity Of Glaciofluvial Deposits: Outcrop Study And Implications For Reactive Transport, Gordon M. Sturgeon

Doctoral Dissertations

Spatial variations in the reactive properties of geologic systems and their influence on contaminant transport are poorly understood. Consequently, an outcrop study was conducted in a glaciofluvial deposit in Deerfield, New Hampshire in order to: (1) identify the sediment properties controlling heavy metal adsorption, (2) evaluate the extent to which geologic information can be used to characterize their spatial variation, and (3) assess the impact of spatial variations on heavy metal transport. Four hundred seventy-six, spatially-located sediment samples were collected from an eight square meter vertical exposure of outwash sands and gravels. Lithologic facies were mapped on outcrop photographs. Sample …

A Three-Level Finite Difference Scheme For Solving A Dual-Phase-Lagging Heat Transport Equation In Spherical Coordinates, Lixin Shen

Doctoral Dissertations

Heat transport through thin films or micro-objects is of vital importance in microtechnology applications. For instance, metal thin films are important components of microelectronic devices. The reduction of the device size to microscale has the advantage of enhancing the switching speed of the device. On the other hand, size reduction increases the rate of heat generation, which leads to a high thermal load on the microelectronic devices. Heat transfer at the microscale is also important for the thermal possessing of materials with a pulsed-laser. Examples in metal processing are laser micromachining, laser patterning, laser processing of diamond films from carbon …

Modeling Of The Inverse Heat -Conduction Problem With Application To Laser Chemical Vapor Deposition And Bioheat Transfer, Peng Zhen

Doctoral Dissertations

This dissertation consists of two parts. Part one deals with three-dimensional laser induced chemical vapor deposition (3D-LCVD), whereas part two deals with a Pennes model of a 3D skin structure. LCVD is an important technique in manufacturing complex micro-structures with high aspect ratio. In part one, a numerical model was developed for simulating kinetically-limited growth of an axisymmetric cylindrical rod by pre-specifying the surface temperature distribution required for growing the rod and then by obtaining optimized laser power that gives rise to the pre-specified temperature distribution. The temperature distribution at the surface of the rod was assumed to be at …

Museum -Based Learning: Informal Learning Settings And Their Role In Student Motivation And Achievement In Science, Julie Ann Holmes

Doctoral Dissertations

This study examined changes in student motivation and achievement in science in relationship with a visit to the IDEA Place Experiment Gallery. The study was based on the pretest-posttest control comparison group design with four treatment groups: control, exhibit, lesson, and exhibit/lesson. The sample was 228 sixth grade students from a public north central Louisiana school who were randomly assigned to one of the four experimental groups. Pretest, posttest, and delayed posttest measures of intrinsic motivation and achievement in science were determined using the Children's Academic Intrinsic Motivation Inventory and an achievement test written to measure areas of science incorporated …

Finite Element Analysis And Statistical Modeling Of Pipeline Rehabilitation Liners With Material Imperfections, Wei Zhao

Doctoral Dissertations

Thin-walled plastic liners are routinely used to rehabilitate structurally sound host pipes that have lost their hydraulic integrity. The liner/host pipe structure is treated as a ring encased in a rigid wall. Significant research work dealing with liner stability has been completed in North America and Europe. These research works include laboratory experiments, numerical analysis, and statistical modeling. The objective of this dissertation is to achieve a better understanding of liner buckling phenomenon using the finite element method and statistical analysis.

Short-term liner buckling models have been applied by several researchers to study the influence of liner geometric imperfections on …