Digital Commons Network^™

Soil Hydraulic Controls Over Nitrogen Oxide Emissions And Nitrogen Cycling In Tropical Agriculture, Antje M. Weitz

Doctoral Dissertations

Soils are the major natural source of nitrous oxide (N2O). Intensive land use increased atmospheric concentrations of this greenhouse gas. Soil microbes produce and consume nitrogen oxides (NO, N2O) during the processes of nitrification (aerobic) and denitrification (anaerobic). Micro-scale variability of controlling factors cause nitrification and denitrification to occur simultaneously in soils, resulting in high spatial variability of nitrogen oxide emissions. Fertilization increases nutrient availability and thus N2O fluxes. Forest soils in the humid tropics account for 20--50% of all N2O sources. Expansion and intensification of tropical agriculture is expected to increase atmospheric N2O concentrations.

We measured N2O fluxes from …

Integration Of Battery Energy Storage With Flexible Ac Transmission System Devices, Zhiping Yang

Doctoral Dissertations

"This dissertation, consisting of five papers, presents the results of research on the incorporation of battery energy storage into a Static Synchronous Compensator (StatCom). The main contribution of this body of work is the establishment of the modeling and control of the StatCom/BESS in power system dynamic applications. The first paper is focused on the steady state characteristics of the StatCom and StatCom/BESS. The characteristic curves of output voltage and output power were proposed and used in comparing the functionality of the StatCom and StatCom/BESS. In the second paper, a StatCom model was proposed and used in power flow analysis. …

Changing And Choosing Together: A Case Study On Improving Professional Development And Student Achievement Through A Teacher-Initiated Early Literacy Program, Theresa Connor Molinelli

Doctoral Dissertations

The purpose of this study was to ascertain teacher's perceptions of the success of an early literacy professional development program designed to achieve more meaningful student assessment, facilitate observation of effective teaching practices, promote teacher-centered staff development, and encourage greater teacher collaboration. This research study also examined the extent to which teachers believed that school- and district-administrative support for this program benefited their classroom teaching practices.

A Thin-Film Micromanufactured Oxygen Microelectrode, James Clay Mcguyer Jr.

Doctoral Dissertations

The methods for production of recessed oxygen microelectrodes developed by Whalen, et al. (1967) and improved upon by Linsenmeier, et al. (1987) are dated production methods by the standards of sensor production of the current time. The production process for this type of polarographic oxygen sensing electrode has remained unchanged for over 10 years, and is a time consuming, extremely low-yield process. The goal of this project has been to use the techniques of micromanufacturing available at the Institute for Micromanufacturing at Louisiana Tech University to construct a recessed oxygen microelectrode with a batch process that has higher yield than …

A Comparison Of Student Achievement, Self-Esteem, And Classroom Interactions In Technology -Enriched And Traditional Elementary Classrooms With Low Socioeconomic Students, Michael Shawn Page

Doctoral Dissertations

The purpose of this study was to compare the attainments of elementary students in technology-enriched classrooms and students in traditional classrooms, while considering performance levels in student achievement, self-esteem, and classroom interactions. Student achievement was measured by the reading and mathematics sections of the Iowa Tests of Basic Skills (ITBS) and the California Achievement Test (CAT). Composite self-esteem, as well as subscale self-esteem levels, was measured by the Coopersmith Self-Esteem Inventories (CSEI), and classroom interaction analysis measurements were conducted using an adaptation of Flanders Interaction Analysis System.

Intact classes from 5 Louisiana elementary schools were randomly assigned to either …

The Microchannel Flow Of A Micropolar Fluid, Guohua Liu

Doctoral Dissertations

Micro-channel flows have been computed to investigate the influence of Navier-Stokes formulation for the slip-flow boundary condition, and a micro-polar fluid model, respectively.

The results of the slip boundary condition show that the current methodology is valid for slip-flow regime (i.e., for values of Knudsen number less than approximately 0.1). Drag reduction phenomena apparent in some micro-channels can be explained by slip-flow theory. These results are in agreement with some computations and experiments.

An ad hoc micro-polar fluid model is developed to investigate the influence of micro effects, such as micro-gyration, in micro-scale flows. The foundation of the ad hoc …

A Study Of Teachers' Perceptions About Staff Development Factors And Their Classroom Implementation Of Reform-Based Science Instruction, Deborah Thompson Silver

Doctoral Dissertations

The purpose of this study was two-fold: (1) to determine whether or not there were significant differences in implementation levels of reform-based science instructional strategies by teachers who participated in an established staff development program, Project LIFE and those who did not, and (2) to distinguish specific program factors that may have impacted the level of implementation of reform-based instructional classroom practices. The instrument used, the Survey of Reform-Based Science Teaching Strategies (SRBSTS ), was developed by the researcher and had reliability of .912 as measured by Cronbach Alpha.

An independent samples t-test analysis was used to compare the …

Environmental Behavior Of Hafnium: The Impact On The Disposition Of Weapons-Grade Plutonium, Gary S. Cerefice '89

Doctoral Dissertations

Experimental and analytical studies were performed to examine the environmental behavior of hafnium and its utility as a neutron poison for the disposition of weapons-grade plutonium in Yucca Mountain. The hydrolysis of hafnium was investigated by potentiometric titration in solutions of varying ionic strength to determine the stability constants for the first four monomeric hydrolysis products. The specific ion interaction theory is used to extrapolate these results to infinite dilution. The solubility of hafnium hydroxide and a meta-stable hafnium carbonate solid phase are studied via solubility experiments using ICP-AES. An upper bound for the stability constant of the first carbonate …

Finite Element Simulation Of Creep Buckling Of Cipp Liners Under External Pressure, Qiang Zhao

Doctoral Dissertations

The problem of long-term structural behavior of CIPP liners under external hydrostatic pressure has been characterized as a structural instability problem which is induced by time-dependent material deformation or creep. It is also a contact problem since the liner deflection is externally constrained by the host pipe. The intrinsically nonlinear problem is investigated by means of finite element simulation, with emphases on (a) the essential structural behaviors and mechanisms of buckling, and (b) the influences of inelastic material properties (i.e. yield strengths and creep rates) and geometrical parameters on liner's buckling resistance.

A liner first deforms as a free pipe …

An Empirical Investigation On The Impacts Of Ground-Level Ozone Concentrations On National Ambient Air Quality Standards: The Case Of Lake Charles, Louisiana, Benedict Nweke Nwokolo

Doctoral Dissertations

This study presents information upon which the state of Louisiana can base its ozone State Implementation Plans (SIPs) designed to achieve planned emissions reduction that are required by the Clean Air Act (CAAA) of 1990. The research investigation included an assessment survey on a number of Transportation Control Measures (TCMs) and their degree of acceptability by the residents of Lake Charles area of Louisiana, the research target area. The TCMS were first ranked on the basis of people's perception of each TCM and four TCMs were later analyzed for cost-effectiveness using computer mathematical models. The Traffic Flow Improvements TCM was …

Optimum Advertising Pulsation Strategies: A Dynamic Programming Approach, Hongkai Zhang

Doctoral Dissertations

This study, using the dynamic programming approach, has addressed the problem of optimally allocating a fixed advertising budget of a monopolistic firm over a planning horizon comprised of n equal periods to maximize two popular measures of advertising performance: (1) profits related to the advertising effort (discount factor r = 0), and (2) present value of profits related to the advertising effort (discount factor r > 0).

Two dynamic programming models that use the modified Vidale-Wolfe model to represent sales response to advertising are formulated with respect to whether the time value of money is considered. For a planning horizon comprised …

A Systematic Integration Of Register Allocation And Instruction Scheduling, Yukong Zhang

Doctoral Dissertations

In order to achieve high performance, processor architecture has become more and more complicated. As a result, compiler-time optimizations have become more and more important for the effective use of a complex processor. One of the promising compiler-time optimizations is the integration of register allocation and instruction scheduling based on register-reuse chains. In the previous approach, however, the generation of register-reuse chains was not completely systematic and consequently created many unnecessary dependencies that restrict instruction scheduling.

This research proposes a new register allocation technique based on a systematic generation of register-reuse chains. The first phase of the proposed technique is …

Graphical Display And Data Structure For Virtual Prototyping, David William Manry

Doctoral Dissertations

One of the goals of engineering firms is to bring better products to market faster. Although concurrent engineering can aid in this endeavor, it requires that all areas of an organization work simultaneously. Thus, current product data must be accessible to everyone.

Virtual prototyping allows this simultaneous exchange of information. Virtual prototyping not only replaces the physical model in product development with a virtual model, but also it goes further by allowing data associated with each part of the model to be accessed. This data is not limited to just geometric properties but could contain other quantifiable properties, such as …

The Dynamics Of Cyberspace: Examining And Modelling Online Social Structure, Brian S. Butler '89

Doctoral Dissertations

It has been proposed that online social structures represent new forms of organizing which are fundamentally different from traditional social structures. However, while there is a growing body of empirical research that considers behavioral aspects of online activity, research on online social structure structural remains largely anecdotal. This work consists of three papers that combine previous studies of traditional social structures, empirical analysis of longitudinal data from a sample of Internet listservs, and computational modeling to examine the dynamics of social structure development in networked environments.

The first paper (Title: When is a Group not a Group: An Empirical Examination …

Dynamic Analysis Of Unevenly Sampled Data With Applications To Statistical Process Control, Laura Ann Mcsweeney

Doctoral Dissertations

Dynamic analysis involves describing how a process changes over time. Applications of this type of analysis can be implemented in industrial settings in order to control manufacturing processes and recognize when they have changed significantly. The primary focus of this work is to construct methods to detect the onset of periodic behavior in a process which is being monitored using a scheme where data is sampled unevenly.

Techniques that can be used to identify statistically significant periodic structure using the periodogram will be reviewed and developed. The statistical properties of the periodogram for unevenly sampled data will be calculated. These …

Analysis Of Impact And Value Of Neasc High School Accreditation Procedures On School Accountability And School Improvement From 1987-1997, George Allan Cushing

Doctoral Dissertations

From a 1983 federal study which concluded, as its title suggests, that America had become A Nation at Risk because of a failing public school system, the modern standards movement was born. This educational reform movement beginning in the 1980's and continuing through the 1990's brought about the development and establishment of many accountability and improvement initiatives aimed at public schools. Also during this time, the New England Association of Schools and Colleges (NEASC), through its Commission on Public Secondary Schools along with five other regional accrediting agencies across the country, was continuously engaged in the practice of evaluating and …

The Word Problem And The Ideal Membership Problem, Damon Anthony Demas

Doctoral Dissertations

This dissertation concerns two problems from computational algebra, the word problem for semigroups and the ideal membership problem for noncommutative polynomial rings. Historically, the word problem provided one of the first examples of an algorithmically unsolvable problem from outside of logic and computability theory. In terms of solvability, the word problem is equivalent to a restricted version of the membership problem.

For ideals whose membership problem is solvable, computational techniques such as Grobner basis methods often can be used to solve the problem, but not always. In Chapter two, we develop a method which can be used to solve the …

Paleoclimatic Significance Of Insoluble Microparticle Records From Canadian Arctic And Greenland Ice Cores, Christian Michel Zdanowicz

Doctoral Dissertations

The past and present variability of climate in the Arctic region is investigated using ice core records of atmospheric dust (microparticles) and volcanic aerosols developed from the Canadian Arctic and Greenland. A high-resolution, 10 4-year long proxy record of atmospheric dust deposition is developed from an ice core (P95) drilled through the Penny Ice Cap, Baffin Island. Snowpit studies indicate that dust deposited on the Penny Ice Cap are representative of background mineral aerosol, and demonstrate that the variability of dust fallout is preserved in the P95 core at multi-annual to longer time scales. The P95 dust record reveals a …

Mentoring In Adolescence: A Sociocultural And Cognitive Developmental Study Of Undergraduate Women And Sixth-Grade Girls In A Mentoring Program, Katharina Maria Fachin Lucas

Doctoral Dissertations

The purpose of this study was two-fold. First, a quasi-experimental study was conducted to explore the cognitive developmental effects of taking on the role of "mentor" as an undergraduate or the role of "mentee" as a sixth grader in one university-based mentoring program. Second, an ethnographic study was conducted to study the experiences of ten sixth graders and ten undergraduates as they took on the role of "mentor" or "mentee" in a planned mentoring relationship. A sociocultural analysis explored processes occurring on the personal, interpersonal, and community level that shaped the mentoring experiences of the participants.

The participants in this …

Central Sequences And C*-Algebras, Hemant Pendharkar

Doctoral Dissertations

We study central sequences of C*-algebras. We find connections of the central sequences of a C*-algebra and its representations. More specifically, we prove the following results: (a) Characterization of central sequences in certain C*-subalgebras of C(X, Mn), where X is a compact Hausdorff space. We also state the conditions under which central sequences are trivial/hypercentral. (b) A representation of the C*-algebra is in the point norm closure of the set of all equivalence classes of irreducible representation if and only if it is multiplicity free. (c) For a C*-algebra A, all of whose representations are bounded by some fixed number, …

Topics In Chaotic Secure Communication, Andrew Thomas Parker

Doctoral Dissertations

Results in nonlinear dynamics and chaos during this decade have been applied to problems in secure communications with limited success. Most of these applications have been based on the chaotic synchronization property discovered by Pecora and Carroll in 1989 [37]. Short [44, 45, 48] demonstrated the effectiveness of nonlinear dynamic (NLD) forecasting methods in breaking this class of communication schemes. In response, investigators have proposed enhancements to the basic synchronization technique in an attempt to improve the security properties. In this work two of these newer communication systems will be analyzed using NLD forecasting and other techniques to determine the …

The Effects Of Reversible Inactivation By Lidocaine Of Ventral Striatum And Intralaminar Nucleus Of The Thalamus In Match To Sample Tasks With And Without Delays Trained In The Lever Box, Mary Christine Porter

Doctoral Dissertations

Three experiments systematically examined the effects of reversibly inactivating intralaminar nuclei and ventral striatum with infusions of lidocaine. The ventral striatum and the intralaminar nucleus were targeted based on deficits in accuracy and speed of responding in delayed conditional discrimination tasks associated with permanent lesions of these structures (Mair, Burk and Porter, 1998).

The present research showed that a 4.0 mul of 2% lidocaine caused impairments accuracy, but not in response speed, in a match to sample task trained in the lever box without delays when the internal cannula projects 0.5 mm from the guide cannula. One microliter of 2%, …

New Methods For Modeling Accelerated Life Test Data, Michelle Hopkins Capozzoli

Doctoral Dissertations

An accelerated life test (ALT) is often used to obtain timely information for highly reliable items. The increased use of ALTs has resulted in nontraditional reliability data which can not be analyzed with standard statistical methodologies. I propose new methods for analyzing ALT data for studies with (1) two independent populations, (2) paired samples and (3) limited failure populations (LFP). Here, the Weibull distribution, which can accommodate a variety of failure rates, is assumed for the models I develop. For case (1), a parametric hypothesis test, a Bayesian analysis and a test using partial likelihood are proposed and discussed. For …

Hardware-Software Codesign In A High-Level Synthesis Environment, Tamas L. Visegrady

Doctoral Dissertations

Interfacing hardware-oriented high-level synthesis to software development is a computationally hard problem for which no general solution exists. Under special conditions, the hardware-software codesign (system-level synthesis) problem may be analyzed with traditional tools and efficient heuristics. This dissertation introduces a new alternative to the currently used heuristic methods. The new approach combines the results of top-down hardware development with existing basic hardware units (bottom-up libraries) and compiler generation tools. The optimization goal is to maximize operating frequency or minimize cost with reasonable tradeoffs in other properties.

The dissertation research provides a unified approach to hardware-software codesign. The improvements over previously …

Thinking Through Performance: Children Make Sense Of Characters And Social Relationships Through A Gesture-Based Theatre Convention (Tableau), Georgia Patricia Wilson

Doctoral Dissertations

This inquiry considers a gesture-based theatre convention called tableau as used by first and second graders during language arts instruction. I argue that tableau acts as a medium of thinking, used to make sense of literary text and of social relationships. Tableau is largely non-language-based; it augments instructional practices that are primarily language-based. Tableau reveals sophisticated understandings children cannot yet put into language. As such, tableau offers educators a means to cast children as capable analysts of literature.

Qualitatively oriented, this inquiry uses instrumental case study methods of observation and data analysis coupled with a concurrent conceptual study of the …

Small Firms, Global Economies: The Economic Sociology Of The Northwest Atlantic Sea Urchin Industry, Sean Raymond Lauer

Doctoral Dissertations

This dissertation examines the organizational dynamics of firms operating in the East Coast sea urchin industry. First, I examine the confluence of economic and political conditions under which the industry evolved. As a part of the export driven growth of the past decade in the US the East Coast sea urchin industry benefited from political conditions, which encouraged development of global markets for US products. Along with this, the Japanese have displayed a seemingly insatiable demand for sea urchin roe through the 1990s. In 1971 the governance of the international monetary system changed from a fixed to floating exchange rate. …

Atmospheric Transport And Deposition Of Water -Soluble Nitrogen To The Gulf Of Maine, Carolyn Estelle Jordan

Doctoral Dissertations

An intensive sampling program was carried out from May 1994 through November 1997 on the shore of the Gulf of Maine in New Castle, New Hampshire. Daily (24 hour averages) samples of bulk aerosol and gas phase HNO3, precipitation, and 20 aerosol size distributions were obtained. Particulate NH4+ and gas phase HNO3 were the dominant water-soluble nitrogen species in the atmosphere. Nitrate was the dominant inorganic nitrogen ion in precipitation.

These samples were used with 1000 hPa streamlines to classify sampled air masses according to their surface level transport and chemistry. Overall, mixed conditions occurred in 42% of the samples, …

Using Writing Composition Pedagogy In An Introductory Teacher Education Practicum To Learn About The Motivations, Journeys, And Understandings Of Preservice Teachers, Daniel Archer Rothermel

Doctoral Dissertations

Over the last third of the twentieth century, best practice in America's public schools has evolved from a focus on the teacher's behavior in presenting material to a focus on whether and how students learn. Over that same period, writing composition pedagogy has focused on the emphasis on students' growth and development as they think reflectively, write drafts, and self-monitor. Integrating writing composition pedagogy in the education of preservice teachers, I use Exploring Teaching, a learner-centered introductory course in teacher education that I teach, as the specific context of my inquiry. As my students write Dear Classmates Letters, portfolio reflections, …

A Constraint-Based Framework For Configuration, Daniel Sabin

Doctoral Dissertations

The research presented here aims at providing a comprehensive framework for solving configuration problems, based on the Constraint Satisfaction paradigm. This thesis is addressing the two main issues raised by a configuration task: modeling the problem and solving it efficiently. Our approach subsumes previous approaches, incorporating both Simplification and further extension, offering increased representational power and efficiency.

Modeling. We advance the idea of local, context independent models for the types of objects in the application domain, and show how the model of an artifact can be built as a composition of local models of the constituent parts. Our modeling technique …

Learning To Read Music Cooperatively In A Choral Setting: A Case Study, Andrew Inzenga

Doctoral Dissertations

Two volunteer cooperative teams of ninth grade girls were studied for six months to discover whether and how they learned to read music. The two teams represented novice students and students who had received private instruction. Study teams represented the population of the freshman Girls Chorus. Teams met regularly during daily chorus rehearsals, with only occasional help from the director. These meetings were analyzed through video tape recordings to observe if students employed traditional teaching and learning strategies to assist each other in learning. It was determined that team members regularly use certain teaching and learning strategies to assist in …