Digital Commons Network^™

Changing Mathematical Discourse: A Case Study Of A Secondary Mathematics Teacher, Mary Lynn Breyfogle

Dissertations

No abstract provided.

Buckling Of Composite Conical Shells Under Combined Axial Compression, External Pressure, And Bending, Youngjin Chung

Dissertations

Conical shells are extensively used in space crafts, robots, shelters, domes, tanks, and in machinery or devices (e.g. as Belleville washers). Thus, the design of minimum weight, maximum strength, stiffened conical (and cylindrical) shells under combined loads has long been of interest to designers. The objective of this study is to improve the strength of conical shells and reduce the weight of the structure. Buckling of composite conical shells subjected to combined axial loading, external pressure, and bending is investigated using energy and finite element methods. The conical shells have single and multiple layers, different cone angle, length, and radius. …

The Structure And Stability Of Expanding And Converging Near-Stoichiometric Flames, Raymond Addabbo

Dissertations

The stability of expanding and converging premixed flames is investigated theoretically. These configurations are inherently unsteady and represent simple examples of positively (expanding) and negatively (converging) stretched flames. A new model is employed in this study that incorporates both hydrodynamic and diffusional-thermal effects. The model expands earlier works by incorporating variable transport properties, variations in the mixture strength and a more realistic dependence on viscosity.

The expanding flame is shown to remain stable at small radii provided the thermal diffusivity exceeds the mass diffusivity of the deficient reactant. However, once the flame achieves a critical size, a cellular instability appears, …

Evolutionary Polymorphic Neural Networks In Chemical Engineering Modeling, Li Gao

Dissertations

Evolutionary Polymorphic Neural Network (EPNN) is a novel approach to modeling chemical, biochemical and physical processes. This approach has its basis in modern artificial intelligence, especially neural networks and evolutionary computing. EPNN can perform networked symbolic regressions for input-output data, while providing information about both the structure and complexity of a process during its own evolution.

In this work three different processes are modeled: 1. A dynamic neutralization process. 2. An aqueous two-phase system. 3. Reduction of a biodegradation model. In all three cases, EPNN shows better or at least equal performances over published data than traditional thermodynamics /transport or …

Asymptotic Methods In Applied Waveguide Problems, Helen Martynov

Dissertations

Some of the most challenging problems in acoustics and electromagnetics involve the study of scattered fields in waveguides caused by targets of elaborate shape. The complexity of the resulting scattered field depends on the geometry of the scatterer, and exact solutions exist only for the simple geometries.

The asymptotic methods developed in this dissertation give the approximate solutions for the scattered fields in two practically important geometries: an object placed inside a stratified waveguide, and a waveguide with multiple abrupt width transitions. The solutions for these geometries are obtained by approximating the field near the target or junction by the …

Saturation Routing For Asynchronous Transfer Mode (Atm) Networks, Jose Luis Ucles

Dissertations

The main objective of this thesis is to show that saturation routing, often in the past considered inefficient, can in fact be a viable approach to use in many important applications and services over an Asynchronous Transfer Mode (ATM) network. For other applications and services, a hybrid approach (one that partially uses saturation routing) is presented. First, the minimum effects of saturation routing are demonstrated by showing that the ratio, defined as f, of routing overhead cells over information cells is small even for large networks. Second, modeling and simulation and M/D/l queuing analysis techniques are used to show that …

Structural, Transport And Magnetic Studies Of Perovskite Bi1-X Cax Mn O3, Hyungje Woo

Dissertations

This dissertation presents an investigation of the fundamental physics of the perovskite system Bi_1-xCa_xMn0₃. This material belongs to a group of simple perovskites called the manganites which are of technological importance for magnetic device applications as read-head sensors.

The Bi_1-xCa_xMnO₃ system is known to exhibit charge ordering (and high sensitivity to magnetic fields) for a much broader range of x than the well-characterized La_1-xCa_xMnO₃ system. However, the properties of Bi_1-xCa_xMnO₃ over the entire doping range are not well understood. …

Detection Of Vapor Phase Mercury Species By Laser Fluorescence Methods, Xiaomei Tong

Dissertations

Elemental and compound mercury are often both volatile and air stable. Several mercury species emissions have been identified in off-gases from industrial processes. The high toxicity of mercury species and the presence of mercury species in municipal waste and coal have prompted a demand for a cost-effective, accurate, and rugged technique for real-time, continuous detection of mercury species vapors. Real-time, continuous emission measurements are important for process control, monitoring, and remediation. At present, there is no commercial continuous emission monitoring (CEM) technique or instrumentation to reliably monitor volatile mercury species emissions from industrial stacks. Conventional measurement methods, such as cold …

Electrostatic Micro Actuators For Mirror And Other Applications, Xingtao Wu

Dissertations

Micro-electro-mechanical systems (MEMS) based electrostatic micro actuators are becoming important building blocks for innovations in optical signal processing and computing systems due to their inherently small size, high density, high speed and low power consumption. Generally, the principle of operation in these systems can be described as: an electrostatic attractive force causes a mechanical rotation, translation or deformation of a mirror plate, controlling the power, phase or direction of a light beam while it propagates through some medium or through free space. The fast paced, competitive research and development efforts widely being undertaken, both in academia and industry, are demanding …

Therapeutic Alliance: Development, Evaluation, And Application Of The Kim Alliance Scale, Son Chae Kim Phd, Msn, Fnp, Rn

Dissertations

The quality of therapeutic alliance between the patient and healthcare provider is a pivotal contributing factor toward optimal healthcare in the current context of rising healthcare costs, shorter hospital stays, and patient's rights. The availability of a well-designed and sound therapeutic alliance instrument can provide understanding and insight into improving the quality of healthcare. The purpose of this study was to develop a reliable and valid therapeutic alliance instrument, to evaluate its psychometric properties, and to explore its usefulness in predicting patient satisfaction. The retroductive triangulation method provided a framework for the development of the instrument, the Kim Alliance Scale …

Vortex-Defect Interactions In High-Temperature Superconductors, Valentina Tobos

Dissertations

The topics covered in this thesis are related to two objectives: one refers to the search for methods of improving die critical current density of high-temperature superconductors, a subject which remains of continuing interest for its importance in technological applications. The other direction is aimed at clarifying the phase diagram of high-Tc materials.

The interaction between the structural defects and the vortex system plays a significant role in the capability of these materials to carry large electrical transport currents. Through proton irradiation induced defects we follow the evolution of the critical current density, and its enhancement with increasing point-like defects …

Empirical Spectral Analysis Of Random Number Generators, David Zeitler

Dissertations

Computer simulation procedures have become a staple of research and development in many fields, including statistics. The generation of pseudo random number sequences is the core of computer simulation procedures. Validity of research results often depend on the underlying validity of the generator being used.

In this work we develop the machinery for a class of tests of spatial uniformity based on a multi-dimensional Fourier transform of the empirical probability density function. The test can be adapted to specific requirements and has the added advantage that it has computational complexity that is relatively independent of the number of data points …

Learning To Construct Proofs In A First Course On Mathematical Proof, Peter R. Atwood

Dissertations

This study examined the conceptions o f proof that undergraduate students have upon entry to a transition course on mathematical proof how they develop skill in planning and reporting proofs, obstacles encountered, and effects of instruction on their performance in solidifying schema in proof-planning and proof-reporting.

The subjects were sophomores and juniors (n=16) in a transition course at a large midwestern university. The course was taught by one o f the co-authors o f the text, "Mathematical Proofs" (Chartrand, Polimeni, and Zhang, 1999, in press). Assessment of learning to construct proofs was through quizzes and a final exam developed by …

The Role Of A Middle School Assistant Principal In Establishing And Maintaining Positive School Climate, Charles R. Girvin Iii Edd

Dissertations

Organizational theorists have for over 50 years used the concept of organizational climate to study and describe the effects of environment on the attitudes and behaviors of individual members and subgroups within organizations. Within the school setting, researchers and practitioners have increasingly used the concept of organizational climate to evaluate school effectiveness, particularly in middle schools where school climate plays a central role in middle school strategies and philosophies. Though extensive research has examined the relationship between climate and leadership in business, industry, and government, relatively few studies have eyed the linkages between school climate and leadership within the school …

Quantification Of Benzo[A]Pyrene-Guanine Adducts In In Vitro And In Vivo Tissue Samples By Lc Tandem Mass Spectrometry, Po-Chang Chiang

Dissertations

No abstract provided.

Cost Domination In Graphs, David John Erwin

Dissertations

Let G be a connected graph having order at least 2. A function f : V (G) —> {0 , 1 , . . . , diam G} for which f ( v ) < e(v) for every vertex v of G is a cost function on G. A vertex v with f ( v ) > 0 is an f-dominating vertex, and the set Vj~ = {v 6 V(G) : f(v) > 0} of f-dominating vertices is the f-dominating set. An /-dominating vertex v is said to f-dominate every vertex u with d(n, v) < f(u ), while …

Parametric Study Of Heavy Metal Partitioning In A Pilot Scale Incinerator Burning Simulated Municipal Solid Waste, Sukrut S. Thipse

Dissertations

Incineration is a combustion process used to convert toxic waste to benign gases and residue in presence of excess air. The products of the incineration process are bottom ash, fly ash and the flue gas. Most of the metal-based phases formed in incineration are toxic and their emissions need to be strictly controlled. Therefore, behavior of metal species during incineration must be well understood. Such understanding is possible based on the experimental identification of the metal phases formed in the waste combustion and determination of their concentration in various incineration products.

A pilot-scale incinerator of 140,000 Btu/hr capacity was constructed, …

Turbo Space-Time Coded Modulation : Principle And Performance Analysis, Dongzhe Cui

Dissertations

A breakthrough in coding was achieved with the invention of turbo codes. Turbo codes approach Shannon capacity by displaying the properties of long random codes, yet allowing efficient decoding. Coding alone, however, cannot fully address the problem of multipath fading channel. Recent advances in information theory have revolutionized the traditional view of multipath channel as an impairment. New results show that high gains in capacity can be achieved through the use of multiple antennas at the transmitter and the receiver. To take advantage of these new results in information theory, it is necessary to devise methods that allow communication systems …

E-Docspros : Exploring Texpros Into E-Business Era, Zhenfu Cheng

Dissertations

Document processing is a critical element of office automation. TEXPROS (TEXt PROcessing System) is a knowledge-based system designed to manage personal documents. However, as the Internet and e-Business changed the way offices operate, there is a need to re-envision document processing, storage, retrieval, and sharing. In the current environment, people must be able to access documents remotely and to share those documents with others. e-DOCPROS (e-DOCument PROcessing System) is a new document processing system that takes advantage of many of TEXPROS's structures but adapts the system to this new environment. The new system is built to serve e-businesses, takes advantage …

Ultrathin Silicon Wafer Bonding Physics And Applications, Michael H. Beggans

Dissertations

Ultrathin silicon wafer bonding is an emerging process that simplifies device fabrication, reduces manufacturing costs, increases yield, and allows the realization of novel devices. Ultrathin silicon wafers are between 3 and 200 microns thick with all the same properties of the thicker silicon wafers (greater than 300 microns) normally used by the semiconductor electronics industry. Wafer bonding is one technique by which multiple layers are formed.

In this thesis, the history and practice of wafer bonding is described and applied to the manufacture of microelectomechanical systems (MEMS) devices with layer thickness on the scale of microns. Handling and processing problems …

Waqs : A Web-Based Approximate Query System, George Jyh-Shian Chang

Dissertations

The Web is often viewed as a gigantic database holding vast stores of information and provides ubiquitous accessibility to end-users. Since its inception, the Internet has experienced explosive growth both in the number of users and the amount of content available on it. However, searching for information on the Web has become increasingly difficult. Although query languages have long been part of database management systems, the standard query language being the Structural Query Language is not suitable for the Web content retrieval.

In this dissertation, a new technique for document retrieval on the Web is presented. This technique is designed …

Broadband Whole Package Fdtd Simulation, Shenjun Li

Dissertations

Whole package analysis is becoming more and more important with the rapid expansion of high frequency electronics. The motivation of this thesis is to find and implement a new method for broadband whole package simulation. 3-dimension (3-D) whole package Finite Difference Time Domain (FDTD) simulation result was first reported in detail in this thesis.

The FDTD method is a widely used full-wave time-domain simulation method used in the design and analysis for electromagnetic (EM) systems, such as antennas, wave propagating, and microwave circuits. Absorbing boundary condition (ABC), such as the perfect matched layer (PML) method, makes it possible to accurately …

Augmenting Applications With Hyper Media, Functionality And Meta-Information, Roberto Galnares

Dissertations

The Dynamic Hypermedia Engine (DHE) enhances analytical applications by adding relationships, semantics and other metadata to the application's output and user interface. DHE also provides additional hypermedia navigational, structural and annotation functionality. These features allow application developers and users to add guided tours, personal links and sharable annotations, among other features, into applications. DHE runs as a middleware between the application user interface and its business logic and processes, in a n-tier architecture, supporting the extra functionalities without altering the original systems by means of application wrappers.

DHE automatically generates links at run-time for each of those elements having relationships …

Fractionation & Segregation Of Suspended Particles Using Acoustic And Flow Fields, Nazhat Aboobaker

Dissertations

The fractionation of particles by size or by density has many applications in a variety of technologies. Decontamination and separation of fine sediments is useful in treating sediments. The application of acoustic standing wave fields for the fractionation and segregation of suspended particles was studied.

The above technology was implemented at the bench scale by building a Plexiglas chamber. Two ultrasound transducers were fixed to opposite sides of the chamber to generate the acoustic standing wave field. The technology was evaluated using silica dioxide (Si02) (1-5 ~tm) and silicon carbide (SiQ (5-20 ~tm) particle suspensions in deionized water. Due to …

Volume Change Behavior Of Clay Soils And The Effect On Discrete Fractures, Heather Ann Hall

Dissertations

This study examines the behavior of subsurface fractures in fine-grained soil such as clays in response to changing environmental conditions. Fractures serve as conduits for moisture transfer, which can lead to substantial shrinking and swelling of the surrounding fracture boundary soils. These volume changes, in turn, affect fracture geometry and moisture transmission rates. A new predictive model, termed the 'Fracture Volume Change Model' (FVC Model), has been developed to relate moisture transfer, soil volume change and associated changes in fracture aperture. The model assumes a discrete horizontal fracture in a laterally-infinite, saturated, expansive clay with rigid, outer no-flow boundaries and …

A Dynamical Model Of The Distributed Interaction Of Intracellular Signals, Adrienne C.N. James

Dissertations

A major goal of modern cell biology is to understand the regulation of cell behavior in the reductive terms of all the molecular interactions. This aim is made explicit by the assertion that understanding a cell's response to stimuli requires a full inventory of details. Currently, no satisfactory explanation exists to explain why cells exhibit only a relatively small number of different behavioral modes.

In this thesis, a discrete dynamical model is developed to study interactions between certain types of signaling proteins. The model is generic and "connectionist" in nature and incorporates important concepts from the biology. The emphasis is …

Knowledge-Based Document Retrieval With Application To Texpros, Fang Sheng

Dissertations

Document retrieval in an information system is most often accomplished through keyword search. The common technique behind keyword search is indexing. The major drawback of such a search technique is its lack of effectiveness and accuracy. It is very common in a typical keyword search over the Internet to identify hundreds or even thousands of records as the potentially desired records. However, often few of them are relevant to users' interests.

This dissertation presents knowledge-based document retrieval architecture with application to TEXPROS. The architecture is based on a dual document model that consists of a document type hierarchy and, a …

An Investigation Of Centrifugal Blood-Cell Separation, Timothy Edward Roche

Dissertations

This dissertation investigated the centrifugal, batch separation of whole blood into subpopulations of red blood cells (erythrocytes) and white blood cells (leukocytes). Separations took place in a custom-built centrifuge (using a seal-less, anti-twisting feed/withdrawal system) containing, a 25-ml capacity separation chamber. The blood separation chamber had dart-shaped geometry in the radial plane and a constant depth in the axial direction. Separation experiments were performed on whole bovine blood at varying hematocrit, centrifuge speed, and batch duration. A small, companion study of whole human blood separation runs also were conducted; they concentrated on batch duration effect and achieved superior separations.

A …

Efficient Inversion Methods In Underwater Acoustics, Xiaoqun Ma

Dissertations

This dissertation describes efficient methods developed and implemented for source localization and sound speed and bottom depth estimation using sound propagation in the ocean. The proposed inversion techniques are based on the linearization of the generally non-linear inverse problem of parameter estimation in underwater acoustics. These techniques take into account properties of the ocean environment and are accurate in their estimation results without being prohibitively computationally intensive. For the inversion, select ray paths are taken into account: the direct, first surface bounce, and first bottom bounce. Ray travel time derivatives with respect to parameters that affect path arrival times are …

Near-Field Imaging With Terahertz Pulses, Oleg Mitrofanov

Dissertations

High spatial resolution imaging is implemented with a novel collection mode near-field terahertz (THz) probe. Exceptional sensitivity of the probe allows imaging with spatial resolution of few microns using THz pulses with spectral content of 120 to 1500 microns. In the present study, the principle of the probe operation as well as the probe design and characteristics are described.

The probe performance is related to effective detection of radiation coupled into the probe aperture. Propagation of short single-cycle electromagnetic pulses through apertures as small as 1/300 of the wavelength is experimentally and numerically studied. Finite-difference time-domain method is used to …