Digital Commons Network^™

Instability Of Electrified Viscous Films, Knograt Savettaseranee

Dissertations

We examine the stability of a thin two-dimensional liquid film with a regular electric field applied in a direction parallel to an initially flat bounding fluid interface. We study the distinct physical effects of surface tension, van der Waals and electrically induced forces for a viscous incompressible fluid. The film is assumed to be sufficiently thin, and the surface tension and electrically induced forces are large enough that gravity can be ignored to the leading order. Our target is to analyse the nonlinear stability of the flow. We attain this by deriving and numerically solving a set of nonlinear evolution …

Development And Characterization Of Methodology And Technology For The Alignment Of Fmri Time Series, Carlo Ciulla

Dissertations

This dissertation has developed, implemented and tested a novel computer based system (AUTOALIGN) that incorporates an algorithm for the alignment of functional Magnetic Resonance Image (fMRI) time series. The algorithm assumes the human brain to be a rigid body and computes a head coordinate system on the basis of three reference points that lie on the directions correspondent to two of the eigenvectors of inertia of the volume, at the intersections with the head boundary. The eigenvectors are found weighting the inertia components with the voxel's intensity values assumed as mass. The three reference points are found in the same …

Two-Dimensional Reflectivity Polarization Elastometry Imaging Techniques (Piet) Of Soft Tissue, Hee Chuan Lim

Dissertations

A non-invasive polarized light reflection measurement method to measure the stretch of soft tissue, such as skin, is described. The technique utilizes changes in the reflectivity of polarized light intensity as a monitor of skin stretch. Measurements on in-vitro pigskin and invivo human skin show that the reflectivity of polarized light intensity increases linearly with stretch over a range. The changes in diffusive reflectivity properties of skin result from the alterations that take place in the roughness across the thickness of the skin layers due to stretch. Conceptually, as the roughness of a layer decreases with stretch, a smoother reflecting …

Process Control Of A Laboratory Combustor Using Neural Networks, Thana Slanvetpan

Dissertations

Active feedback and feedforward-feedback control systems based on static-trained feedforward multi-layer-perceptron (FMLP) neural networks were designed and demonstrated, by experiment and simulation, for selected species from a laboratory two stage combustor. These virtual controllers functioned through a Visual Basic platform. A proportional neural network controller (PNNC) was developed for a monotonic control problem - the variation of outlet oxygen level with overall equivalence ratio (Φ₀). The FMLP neural network maps the control variable to the manipulated variable. This information is in turn transferred to a proportional controller, through the variable control bias value. The proposed feedback control methodology …

Experimental Studies Of Wave Propagation In Three-Dimensional Photonic Crystals, John M. Tobias

Dissertations

Photonic crystals were proposed fifteen years ago. Propagation is selectively prevented through these crystals resulting in a photonic band gap, that is, a frequency region where light cannot propagate. These frequency bands are analogous to electronic band gaps in solid-state crystals.

The optical properties of the photonic crystal in regions near the band gap remain relatively unexplored. Yet, there is significant evidence to suggest that this avenue of investigation can provide useful optical and microwave applications. Numerical studies have predicted that the effective permittivity near the photonic band gap approaches zero and becomes negative. Selfcollimation of the propagating beam and …

A Bi-Level Programming Approach For The Shipper-Carrier Network Problem, Ya Wang

Dissertations

The Stackelberg game betweenshippers and carriers in an intermodal network is formulated as a bi-levelprogram. In this network, shippers make production, consumption, androuting decisions while carriers make pricing and routing decisions.The oligopolistic carrier pricing and routing problem, which comprisesthe upper level of the bi-level program, is formulated either as a nonlinearconstrained optimization problem or as a variational inequality problem,depending on whether the oligopolistic carriers choose to collude orcompete with each other in their pricing decision. The shippers' decisionbehavior is defined by the spatial price equilibrium principle. Forthe spatial price equilibrium problem, which is the lower level of thebi-level program, a …

An Analysis Of Field Data For Evidence Of Anaerobic Degradation Of Pah And Btex Plumes At Manufactured Gas Plant Sites, Georgene Mortimer

Dissertations

Field data (including geology, hydrogeology, soil chemistry, groundwater chemistry, and aquifer characteristics) were analyzed at eight MGP sites located in the New Jersey Coastal Plain. These data were used to calculate biodegradation rate constants, which were then compared with laboratory microcosm data and published values. Isopleths were drawn from the field data to indicate the dominant biodegradation mechanisms at each of the sites, and stoichiometric calculations were used to determine the total capacity of the electron acceptors present to degrade the plume contaminants. In examining these data, the protocol described by the Air Force Center for Environmental Excellence (AFCEE) was …

Collaborative Problem Solving And Program Development Model, Joanna Defranco-Tommarello

Dissertations

A model to enhance collaborative problem solving and program development is presented. The collaborative model is a detailed cognitive model that takes into consideration the cognitive and social activities that occur during collaborative problem solving and program development. The cognitive activities required for collaborative problem solving and program development are identified and integrated into a six-stage model. An extensive literature review in the associated fields is presented to show the need for the model described in this dissertation. In addition, a comprehensive study of tools to support collaboration during problem solving and program development was also performed as well as …

Concurrent Evaporating Spray Jets In Dilute Gas-Solid Pipe Flows, Xiaohua Wang

Dissertations

Evaporating spray jets into gas-solids suspensions are encountered in many industrial applications. The rapid evaporation of spray jets has significant effects on the gas-solids mixing near the jet nozzle regions, including non-uniform solids concentration dilution, gas/solids temperature reduction, and gas/solids velocity acceleration. Furthermore, the jet structure is altered by the change of solids loading, jet mass flow rate and initial droplet size distribution. These interactions of gas, solids and evaporating droplets dominate the process efficiency and product quality. There is an urgent need for exploring fundamental mechanisms of the multi-phase interactions with heat and mass transfer as there are few …

Genre Studies: Temporary Homogeneous Grouping To Improve Reading Or Merely Another Form Of Tracking?, Brenda Wright Campbell Edd

Dissertations

For the last fifty years, raising the achievement levels of students thought to be “at-risk” has proven to be one of the most difficult and vexing problems facing educators. Although many different strategies have been tried with varying levels of success, no single at-risk solution has emerged that both promotes significant achievement gains and helps to narrow the achievement gap between people of color and whites. This study examined the effectiveness of a particular district-wide literacy strategy in its first year that focused on literacy to educate students identified as “at-risk”. Specifically, this study used data gathered from two measures …

Prenatal Maternal Attachment: The Lived Experience, Regina Ann Leva-Giroux Dnsc

Dissertations

Prenatal maternal attachment and the practice of health promoting behaviors during pregnancy are considered universal phenomena to women. Yet, the understanding of these phenomena from the lived experiences of pregnant women has not been well researched. The purpose of this phenomenological study was to describe the experience of maternal attachment to the unborn child and how that attachment might relate to the practice of these behaviors during pregnancy. The participants in this study were ten English speaking women, college educated, professionally employed, who were pregnant for the first time. Unstructured interviews were conducted with the participants at 14–16 weeks and …

An Examination Of The Effects Of Fluency Training On Retention, Distractibility, And Generativity, Victoria Mary Pellettiere

Dissertations

The Precision Teaching movement grew out of a commitment to use frequency as a universal measure of behavior, as well as the desire to employ research methods derived from the experimental analysis of behavior in education (Lindsley, 1991). One component of instruction employing the precision teaching model is fluency training that typically involves exposing learners to the training materials until they have met criteria for both accuracy and speed. Proponents of fluency training ascribe a number of specific benefits to this instructional tool. Lindsley (1992, 1995) and others (Binder, 1993, 1996; Haughton, 1981b) suggested that fluency training enhances retention, endurance, …

Chemical, Isotopic, And Hydrogeologic Investigations Of An Agriculturally Impacted Area, Nottawa Creek Watershed, Calhoun County, Michigan, Gerald A. Unterreiner

Dissertations

A 4 km2 agricultural area within the somewhat poorly drained Nottawa Creek Watershed, south central Michigan, was investigated to help understand transport and transformation processes of nutrients and herbicides to surface water. Geology o f the study area is comprised of a thin glacial drift cover overlying shale bedrock. A one layer, two-dimensional numerical triangular finite element groundwater flow model was developed to evaluate regional groundwater flow. Selected horizontal hydraulic conductivities ranged from 3 x 10‘3 m/day to 107 m/day. Field-scale infiltration modeling with the computer program GLEAMS, substantiated with water level measurements, suggest significant recharge events occur during summer, …

Systematic Methods For The Design Of A Class Of Fuzzy Logic Controllers, Saad Y. Yasin

Dissertations

Fuzzy logic control, a relatively new branch of control, can be used effectively whenever conventional control techniques become inapplicable or impractical. Various attempts have been made to create a generalized fuzzy control system and to formulate an analytically based fuzzy control law. In this study, two methods, the left and right parameterization method and the normalized spline-base membership function method, were utilized for formulating analytical fuzzy control laws in important practical control applications. The first model was used to design an idle speed controller, while the second was used to control an inverted control problem. The results of both showed …

A New Theory Of Premixed Flames In Near-Stoichiometric Mixtures, Eliana S. Antoniou

Dissertations

In this dissertation, a new model of premixed flames in near-stoichiometric mixtures is derived. Unlike most previous theories, which are valid only for very lean or very rich, i.e. off-stoichiometric conditions, our model remains valid over the entire spectrum of mixture compositions, from lean to rich, including the near-stoichiometric regime. Since fuel-mixture composition is known to have a significant effect on flame behavior, such a model is expected to contribute new insights into classical problems in premixed combustion.

In the first part of this dissertation, we describe the derivation of a model for premixed flames in two-reactant mixtures in a …

Simultaneous Removal Of Ortho-Dichlorobenzene And Ethanol Vapors In A Biotrickling Filter : Experimental Results And Process Modeling, Suchismita Bhattacharya

Dissertations

This study investigated the possibility of simultaneous removal of vapors of dissimilar volatile organic compounds from air streams in a biotrickling filter (BTF). Using a rricrobial consortium known to utilize ortho-dichlorobenzene (o-DCB) as sole carbon and energy source, a culture was developed on o-DCB/ethanol mixtures and a BTF unit was developed and operated with air streams carrying o-DCB and ethanol vapors. Simultaneous removal of the two compounds was observed in experiments that span a period of over three years.

Experiments were performed at air residence times ranging from 4 to 6.5 min, liquid flow rates from 3.6 to 9 Lh …

Application Of Chemical Kinetic Modeling To Improve Design And Performance Criteria For A Practical Incineration System, Charles A. Bass Jr.

Dissertations

In this study, detailed thermo-chemical kinetics with networked ideal reactor model were applied to simulate a practical combustion system -the Secondary Combustion Chamber (SCC) of the Rotary Kiln incineration Simulator (RKIS) at the EPA facility at Research Triangle Park, NC. The networked ideal model was developed using analysis of reactor geometry, temperature profile measurements, and SO₂ tracer data provided by EPA. A computer simulation of the networked model was developed using the CHEMKIN H library. A parallel effort considered the effects of non-ideal mixing on detailed thermo-kinetic, simulations. Specifically, an alternate approach was developed to solve the Partially Stirred …

On Performance Analysis And Implementation Issues Of Iterative Decoding For Graph Based Codes, Xuefei Wei

Dissertations

There is no doubt that long random-like code has the potential to achieve good performance because of its excellent distance spectrum. However, these codes remain useless in practical applications due to the lack of decoders rendering good performance at an acceptable complexity. The invention of turbo code marks a milestone progress in channel coding theory in that it achieves near Shannon limit performance by using an elegant iterative decoding algorithm. This great success stimulated intensive research oil long compound codes sharing the same decoding mechanism. Among these long codes are low-density parity-check (LDPC) code and product code, which render brilliant …

On The Data Hiding Theory And Multimedia Content Security Applications, Litao Gang

Dissertations

This dissertation is a comprehensive study of digital steganography for multimedia content protection. With the increasing development of Internet technology, protection and enforcement of multimedia property rights has become a great concern to multimedia authors and distributors. Watermarking technologies provide a possible solution for this problem.

The dissertation first briefly introduces the current watermarking schemes, including their applications in video,, image and audio. Most available embedding schemes are based on direct Spread Sequence (SS) modulation. A small value pseudo random signature sequence is embedded into the host signal and the information is extracted via correlation. The correlation detection problem is …

Development Of Analytical Systems And Monitoring Of Vocs Emissions During Polymer Processing, Qin Xiang

Dissertations

A method using direct flame ionization detector (FID) measurement was developed to study total volatile organic compounds (VOCs) emissions during thermal degradation of polymers. This was used to estimate organic emissions from both virgin polymer resins and commingled plastics. The effects of process parameters, i. e., temperature, heating rate and residence time, were also studied. Significant VOCs emissions were observed at normal processing temperatures, particularly from recycled polymers. Each polymer showed a distinct evolution pattern during its thermal degradation. Kinetics of VOCs emissions were also studied using a non-isothermal technique. The kinetic parameters were in agreement with data from the …

Computation And Control Of Flow-Induced Noise Behind A Circular Cylinder Using An Acoustic Analogy Approach, Sirivit Taechajedcadarungsri

Dissertations

The computational aeroacoustics (CAA) research, which focuses on predicting acoustics by means of advanced numerical techniques, has recently gained a great deal of progress. In most applications, the prediction of both the sound source and its far-field propagation is necessary as required by regulations. Recently, powerful computers and reliable algorithms have allowed the prediction of far-field noise through the use of Computational Fluid Dynamics (CFD) data as near-field sound sources. One of the most useful analytical methods, used for the computation of noise, is Lighthill's acoustic analogy. The latter will be used in the present study.

Lighthill's acoustic analogy, combined …

Renegotiation Based Dynamic Bandwidth Allocation For Selfsimilar Vbr Traffic, Zafer Sahinoglu

Dissertations

The provision of QoS to applications traffic depends heavily on how different traffic types are categorized and classified, and how the prioritization of these applications are managed. Bandwidth is the most scarce network resource. Therefore, there is a need for a method or system that distributes an available bandwidth in a network among different applications in such a way that each class or type of traffic receives their constraint QoS requirements.

In this dissertation, a new renegotiation based dynamic resource allocation method for variable bit rate (VBR) traffic is presented. First, pros and cons of available off-line methods that are …

Modeling Hydrogen Diffusion For Solar Cell Passivation And Process Optimization, Yi Zhang

Dissertations

A diffusion model for hydrogen (H) in crystalline silicon was established which takes into account the charged state conversion, junction field, mobile traps, and complex formation and dissociation at dopant and trap sites. Carrier exchange among the various charged species is a "fast" process compared to the diffusion process. A numerical method was developed to solve the densities of various charged species from the Poisson's equation that involves shallow-level dopants and one "negative U" impurity, e.g., H. Time domain implicit method was adopted in finite difference scheme to solve the fully coupled equations.

Limiting versions of the model were applied …

Aircrew Adaptive Decision Making: A Cross-Case Analysis, Constance Ann Gillan Edd

Dissertations

Although the accident rate for military aviation has declined significantly from earlier decades, during the 1990's it reached a plateau. Human error in the cockpit still accounts for over 80% of the aircraft mishaps resulting in loss of life or over one million dollars in damage. Decision error has been a contributing factor for approximately 60% of these mishaps. The purpose of this research was to investigate aircrew process performance variables as predictors of decision-making outcomes. This study was modeled on elements of previous research in naturalistic decision making. Data were collected for cross-case analysis of the role experience plays …

Modeling The Effects Of Financial Aid On Student Enrollment Decisions: A Quantitative Case Study Of A Private Catholic University, Linda Siefert Edd

Dissertations

Over the last two decades, many institutions of higher education have experienced admissions-related problems due to fluctuations in student enrollment and the increasing need for institutional financial aid. Because of this, administrators need tools that can help them modify policy as the market changes. The purpose of this research was to develop a tool for a private, more selective institution that would answer the following questions: (1) what is the probability of enrollment for each admitted student, and (2) how would changes in the financial aid package affect this probability? The model in this research was based on both economic …

A Model Health-Related Elementary Physical Education Program For Saipan: Teachers' Knowledge, Attitudes, And Practices, Kurt C. Barnes Edd

Dissertations

The purpose of this study was to determine if there was significant differences in changes of knowledge, attitudes, and practices between elementary school teachers who took part in an in-service physical education training program and those who did not take part. The in-service training program utilized a model health-related physical education program. The setting for the study was a school district on Saipan whose teachers were required to teach physical education. Teachers in five of nine public elementary schools were placed in the in-service training program. A questionnaire assessing knowledge, attitudes, and practices, was administrated as a pre- and post-test. …

Means And Ends Of The Andrews University Leadership Program: A Study Of Its Critical Components And Outcomes As They Relate To The Mission Statement, José A. Alaby

Dissertations

Problem. The history of education shows tensions between its means and ends. Tensions became more apparent in contemporary Christian educational institutions. The Leadership Program (LP) of Andrews University was developed as an alternative and innovative means of delivering graduate education with a defined mission. It is job-embedded-theory and practice are united in the participants' workplaces, where they show their competency in 20 areas. It stresses the importance of the individuality of the participant in the development of a teaching/learning community. Yet, the dialectical relationship of the LP's ends and means has not been systematically studied in light of its …

A Legal History Of The Job Corps, Joseph E. Blackett

Dissertations

Purpose. The purpose of this dissertation was to construct the legal history of the Job Corps. I focus on five basic questions that guide the study: (1) What were the statutes that created the Job Corps? (2) What was the mission of the Job Corps? (3) How did the Job Corps change over time? (4) What effect did legal challenges have on the Job Corps? and (5) What changes were brought about by recent legislation?

Method. This study involved three basic activities: review of available sources of data to secure information relevant to the five focus questions in the purpose …

Variables Related To The Successful Completion Of The First Course In Business Calculus At Three Jamaican Universities, Martin Nkhrama Richards

Dissertations

Problem. Many students at all levels of the education system in Jamaica perform poorly at mathematics. In particular, the results of both the Caribbean Examinations Council and Business Calculus 1 at the university level have reflected a declining trend in mathematics performance in recent years. Consequently, this study sought to investigate the variables related to the successful completion of the first course in business calculus at Jamaican universities. To this end, the study looked at perceptions of students and their professors regarding students' cognitive, affective, and professor effectiveness variables impacting success.

Method. The sample for this study consisted of 389 …

Exemplary Bilingual Teachers In Puerto Rico: A Multiple-Case Study, Aurea Laracuente Araújo

Dissertations

Problem. Within a context of inadequate pre-service training, insufficient administrative support, and an ambivalent social environment regarding the teaching of ESL in Puerto Rico, a number of conscientious bilingual teachers try to overcome the odds of the system and have an impact on students' ability to speak English. Some even become exemplary teachers. How do they learn to meet so many expectations successfully in spite of real short comings found in their job, and how do they acquire the skills and competencies necessary to be exemplary bilingual teachers in Puerto Rico?

Method. A qualitative multiple-case study design was …