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Constitutive Equation For Concrete Using Strain-Space Plasticity Model, Yuxiang Xing

Dissertations

Plasticity theory has been used to model the concrete constitutive relationship for about two decades. With the modifications and refinement based on experimental data, achievement has been made in these plasticity models for concrete. Almost all the existing models are developed in stress space. With a lot of experimental data and more understanding about stress states of concrete, the stress-space model shows many advantages. Because of this and also due to conventional engineering practice, the stress-space plasticity approach has been in the dominant position. However, the conventional stress-space plasticity method has one inherent drawback in which it cannot deal with …

On Orthogonal Collocation Solutions Of Partial Differential Equations, Herli Surjanhata

Dissertations

In contrast to the h-version most frequently used, a p-version of the Orthogonal Collocation Method as applied to differential equations in two-dimensional domains is examined. For superior accuracy and convergence, the collocation points are chosen to be the zeros of a Legendre polynomial plus the two endpoints. Hence the method is called the Legendre Collocation Method. The approximate solution in an element is written as a Lagrange interpolation polynomial. This form of the approximate solution makes it possible to fully automate the method on a personal computer using conventional memory.

The Legendre Collocation Method provides a formula for …

Minimum Redundancy Array Structure For Interference Cancellation, Wan-Ling Chen

Dissertations

Adaptive antenna arrays are widely used in many advanced radar, sonar, and communication systems because of their effectiveness in cancelling intentional or unintentional interferers. A uniformly spaced linear array, referred to as a Uniform Regular Array (URA), is the usual structure used for interference cancellation. The Minimum Redundancy Array (MRA) structure proposed in this work is a special kind of thinned array whose application was limited in the past to direction finding. MRAs with the same number of array elements can resolve directions of much more closely spaced signals than URAs.

The URA structure is customarily utilized for interference cancellation, …

Tensile Behavior Of Concrete And Mortar Under Direct Impact Tensile Load, Kayumars Emad

Dissertations

Structures are often subjected to impact loadings during their lifetime. Most structural specifications including the special provisions for seismic design in the current ACI building codes, have been developed on the basis of quasi-static assumptions. Cement composites are strain rate sensitive materials therefore, their properties determined under quasi-static condition should not be used to predict their performance under high strain rates.

The objectives of this investigation are:

• to develop a standard test set-up for direct tensile testing of cementitious composites.
• to study the tensile behavior of mortar and concrete under direct impact tensile load.
• to develop a simplified formula to …

Algorithms For Generation Of Path-Methods In Object-Oriented Databases, Ashish Mehta

Dissertations

A path-method is a mechanism in object-oriented databases (OODBs) to retrieve or to update information relevant to one class that is not stored with that class but with some other class. A path-method is a method which traverses from one class through a chain of connections between classes to access information at another class. However, it is a difficult task for a user to write path-methods, because it might require comprehensive knowledge of many classes of the conceptual schema, while a typical user has often incomplete or even inconsistent knowledge of the schema.

This dissertation proposes an approach to the …

Dmodel And Dalgebra : A Data Model And Algebra For Office Documents, Fortune Solani Mhlanga

Dissertations

This dissertation presents a data model (called D_model) and an algebra (called D_ algebra) for office documents. The data model adopts a very natural view of modeling office documents. Documents are grouped into classes; each class is characterized by a "frame template", which describes the properties (or attributes) for the class of documents. A frame template is instantiated by providing it with values to form a "frame instance" which becomes the synopsis of the document of the class associated with the frame template. Different frame instances can be grouped into a folder. Therefore, a folder is a set of frame …

Characterization Of Advanced Etching Reactors Using Novel Diagnostic Tools, Vipulkumar Patel

Dissertations

Plasma etching equipment used for sub-micron integrated circuit fabrication at present are exclusively based on 13.56 MHz, capacitively coupled, parallel-plate geometry. The underlying mechanisms of plasma processes in these reactors are not well understood and there is even less understanding of how the etch-tool parameters relate to the plasma discharge characteristics which actually determine the etch process. In this thesis, new diagnostic techniques were applied for the characterization and optimization of plasma etching processes in various reactor configurations.

Specifically, diode and triode configurations were studied extensively using tuned scanning Langmuir probes. Both radial and axial distributions of plasma density were …

Kinetic Study Of Decomposition Of Azo Dyes And Phenol In Advanced Oxidation Processes Reaction Mechanisms, Pathways And Intermediates, Hung-Yee Shu

Dissertations

Advanced Oxidation Processes (AOP) are an emerging technology for treatment of various hazardous organics in wastewater and groundwater. However, the kinetics and mechanisms for AOP have not been well understood. A mechanism including light intensity was studied for the decomposition of azo dyes and phenol in an AOP reactor with a 5,000 watt low pressure mercury lamp. UV light absorption is an important parameter. The effect of pH, hydrogen peroxide dosage, and dye concentration on the decomposition of azo dyes in an H₂O₂/UV reactor were also studied. Reaction pathways and intermediates of phenol oxidation by different …

Unreinforced Masonry Structures : Nonlinear Analysis And Evaluation Of Some Rehab Schemes, Sanjay Mehta

Dissertations

Unreinforced masonry (URM) structures have been a common type of construction in the past and are still used in regions of low seismicity. Retrofitting of these structures is necessary because of two reasons: Firstly, observed damage after earthquakes reveals that URM construction is one of the most hazardous constructions even in the region of low seismicity; secondly, reclassification of seismic zones would require retrofitting of existing structures to comply with new guidelines for earthquake design.

Retrofitting measures require that the response of original and new structural systems as well as their interaction be considered. It is therefore important to correctly …

Megsdf Mega-System Development Framework, Tamar Zemel

Dissertations

A framework for developing large, complex software systems, called Mega-Systems, is specified. The framework incorporates engineering, managerial, and technological aspects of development, concentrating on an engineering process. MegSDF proposes developing Mega-Systems as open distributed systems, pre-planned to be integrated with other systems, and designed for change.

At the management level, MegSDF divides the development of a Mega-System into multiple coordinated projects, distinguishing between a meta-management for the whole development effort, responsible for long-term, global objectives, and local managements for the smaller projects, responsible for local, temporary objectives.

At the engineering level, MegSDF defines a process model which specifies the tasks …

Utilization Of Fly Ash In Concrete, Chai Jaturapitakkul

Dissertations

Fly ash, a by-product of coal burning power plants, is produced in large quantities each year. It is commonly known that fly ash possesses pozzolanic behavior which can enhance the properties of concrete. Due to a lack of proper understanding on the formation of fly ash and its performance in concrete, the question of quality assurance has frequently been a major concern of engineers using fly ash in their construction projects. As a result, much fly ash is disposed of as waste material in landfills. Recent environmental concerns and a shortage of landfill space have rapidly escalated the disposal cost …

Competition Between Two Microbial Populations In A Sequencing Fed-Batch Reactor And Its Implications For Waste Treatment Applications, Sitaram Dikshitulu

Dissertations

Pure and simple competition between two microbial populations in a sequencing fed-batch reactor (SFBR) was studied both at the theoretical and experimental level. Competition occurred for a single chemical pollutant which could serve as the sole carbon and energy source for both competitors. A mathematical model describing the process under inhibitory kinetics (as is usually the case with hazardous and toxic substances) was derived and theoretically analyzed. The model predicts that the dynamics of a SFBR, and the kinetics of biodegradation, result in a complex set of operating regimes in which neither species, only one species, or both species survive …

From Untrained Nurses Toward Professional Preparation In Montana, 1912-1987, A. Gretchen Mcneely Dnsc, Msn, Rnc

Dissertations

Since the American Nurses' Association (ANA) published its first position paper in 1965 and in 1978 reaffirmed its position on the educational preparation for nursing practice at the ANA National Biennium, the Montana Nurses' Association (MNA) has maintained a consistent position that a minimum of the baccalaureate degree in nursing should be required for licensure as a professional nurse. As of the closure of the 1987 session, the MNA had not yet been able to secure legislation for this requirement. The influence of the Montana Nurses' Association on the legislative process regarding the regulatory efforts of the profession from 1912 …

Self-Control And Choice In Children: Effects Of Food Magnitude And Reinforcer Delay, Ellen Lee Sharenow

Dissertations

The present research was designed to replicate and extend earlier studies with humans and nonhumans in the area of self-control. A discrete trial, within-subject experimental design over multiple sessions, with food as the reinforcer, was used. Instructions did not describe contingencies of reinforcement Subjects were preschool age children, a population that questionably possess the verbal repertoire capable of generating sophisticated tacting, or mediating behavior during long delays. Four experiments consisted of fixed-ratio, concurrent chain schedules with initial and terminal links. Initial links were forced trials, terminal links, choice trials. In Experiment I, the effects of differences in magnitude while holding …

The Impact Of Test Sophistication On Tenth Grade Students’ Michigan Educational Assessment Program (Meap) Scores, Iris Williams

Dissertations

The primary purpose of this study was to determine whether test sophistication training would result in more tenth grade students achieving performance levels on the Michigan Educational Assessment Program (MEAP) subtests in mathematics and reading which would entitle them to receive the state endorsed diploma.

Two groups of English II students (grade 10) from the same school participated in the study. One group received test sophistication instruction, and the other received no treatment. During the test sophistication training, students were instructed using the Ace That Test Preparation for Success Student Guide (Yarosz & Yarosz, 1991a) which was based on the …

Comparison Study Of The Implementation Rate Of Eighteen Middle School Characteristics In Michigan And National Blue Ribbon Schools, Gregg G. Mowen

Dissertations

The purpose of this study was to determine the current amount of Implementation of the 18 middle school characteristics as reported by principals from randomly selected middle level schools In the state of Michigan and In middle level schools designated as Blue Ribbon schools (U.S. Department of Education, 1991). This study used a survey questionnaire that was initially designed by RIegle (1971) to measure the rate of Implementation of the middle school characteristics. The survey was mailed to Michigan and Blue Ribbon middle level school principals, selected randomly via a table of random numbers. The return rate for Michigan schools …

The Effects Of Differing Response Force Requirements On Response Rate And Post-Reinforcement Pause, Kenneth Lee Ailing

Dissertations

The present study consisted of three experiments in which rats were exposed to two-component multiple schedules of reinforcement. In the first experiment, fifteen responses were required to produce reinforcement in both components of the multiple schedule. In one component 25 g of downward force was always required to operate the response lever. In the other, the force required varied from 25 g to 200 g across conditions. In the second experiment, fifteen responses were required to produce reinforcement in both components of the multiple schedule. In one component 25 g of downward force was always required to operate the response …

Robust Rank-Based Inference Procedures In The Heteroscedastic Linear Model, Sherry L. Dixon

Dissertations

No abstract provided.

Analysis Of The Optimum Extraction System Design For The Separation And Purification Of Rare Earths, Kenneth Yeon-Kang Chan

Dissertations

A mathematical model for the liquid-liquid equilibrium of the lanthanide and yttrium oxides in the nitric acid - water - tributyl phosphate (HNO₃-H₂O-TBP) two-phase system has been developed. This model is based on the interrelationships of chemical reactions, phase equilibrium, and material balance. The chemical reactions were modelled using experimentally derived empirical equations for components involved. The distribution coefficients of 16 rare earths which were experimentally determined. by UK Harwell Laboratory were used to evaluate the parameters of this equilibrium model. Once model parameters are determined, material balance for all species in the HNO₃-H …

Analysis Of A Band-Saw, Suat Ali Ozsoylu

Dissertations

The solution for the transverse oscillations of a band-saw is determined. Two different models are treated: a fourth-order model and a second-order model. The response characteristics for both models are determined using Laplace transformation. To obtain the inverse Laplace Transform for the fourth-order model, it was necessary to fmd the frequencies by applying the Extended Lanczos Method in order to overcome the problem for computer overflow.

The limits of stability for both models are studied by plotting the eigenvalues against changing parameter values. Conditions for the onset of divergence and flutter instabilities, which need to be taken into account in …

Kinematic Synthesis Of Adjustable Four-Bar Mechanisms For Multi-Phase Motion Generation, Shao Jie Wang

Dissertations

A four-bar linkage can satisfy up to five prescribed positions for the motion generation problem. The adjustable four-bar linkage, on the other hand, can satisfy more than five given positions by making some of the parameters adjustable.

Limited work had been done in the area of motion generation problems of kinematic synthesis of adjustable four-bar linkages until Wilhelm introduced the concept of multiple adjustments.

This study considers for the first time, the adjustment of a moving pivot, and the problems of three phases of motion. Various combinations of the number of prescribed positions for the motion generation problems are solved …

Study Of Surface Properties Produced By Magneto-Plasma On Nitriding For Improving Wear Resistance, I-Tsung Shih

Dissertations

In this work a newly developed surface treatment process, Magneto-Plasma Ion Nitriding process, was developed and studied. This process was developed to increase durability and wear resistance of operational surfaces of different machine components.

In this study, orthogonal experimental analysis was used to develop, optimize, and select the process parameters. Coating layers were characterized and studied by using scanning electron microscopy(SEM), Auger electron spectroscopy(AES), and image analysis system. The influence of different process treatment parameters, such as temperature, nitrogen concentration, and magnetization, on the layers properties was studied. The mechanism of layer formation and bonding was proposed and a mathematical …

Investigation Of The Striation Formation In The Course Of Abrasive Waterjet Cutting, Jo-Fei Chao

Dissertations

The principal defect of the surfaces generated by abrasive waterjet machining is excessive waviness (striation). The existing theories of striation formation are not adequate to explain this phenomenon. The presented study is concerned with the development of an understanding of the mechanism of striation formation.

A spectral analysis of temporal process and spatial surface characteristics demonstrated that the striation is caused by nozzle vibration that is due to the conditions of the motion control of the nozzle. This enabled us to discover a means for improving the surface finish. From a study of the surface spectra, it was found that …

Investigation Of The Consumer Electronics Bus, Jaesoo Yang

Dissertations

The objectives of this dissertation are to investigate the performance of the Consumer Electronics Bus (CEBus) and to develop a theoretical formulation of the Carrier Sense Multiple Access with Contention Detection and Contention Resolution (CSMA/CDCR) with three priority classes protocol utilized by the CEBus

A new priority channel assigned multiple access with embedded priority resolution (PAMA/PR) theoretical model is formulated. It incorporates the main features of the CEBus with three priority classes. The analytical results for throughput and delay obtained by this formulation were compared to simulation experiments. A close agreement has been found thus validated both theory and simulation …

On Adaptive Censored Cfar Detection, Loizos Anastasiou Prastitis

Dissertations

In an automatic radar detection system the received signal in every range resolution cell is compared with a threshold to test for the presence of a target. A Neyman-Pearson type test is used which maximizes the probability of detection for a fixed probability of false alarm. For the simple case where the noise is homogeneous a fixed threshold is chosen to achieve the designed constant false alarm rate (CFAR). In the more realistic case the noise background is non-stationary due to clutter and interference. In this situation, the threshold used for testing a particular cell is usually set adaptively using …

Investigation Of Reactor Design Parameters Towards Optimizing Biodegradation Of Chlorophenols By Phanerochaete Chrysosporium, Nirupam Pal

Dissertations

The biodegradation of 2,4,6-trichlorophenol (246-TCP) and 2,4,5-trichiorophenol (245-TCP) by Phanerochaete chrysosporium was studied in batch and in continuous systems. Contrary to most of the previous reports from the literature, this study shows that degradation of both TCPs can occur in the absence of any measurable ligninase activity. The microorganism did not retain its degradative ability for more than about two weeks

In order to better understand the degradation process, the individual contributions of both the biomass and the extracellular proteins were studied separately. The results show that neither the biomass nor the extracellular proteins alone can completely degrade 246-TCP, but …

Effective Administration And Implementation Of External Programs Addressing Social Issues Operating Within Schools, Roselyn R. Cole

Dissertations

Problem. It is difficult for schools to make sound decisions regarding whether to use external programs to address teenage pregnancy, AIDS, substance abuse, or any other social issue. Questions arise as to which administrative factors impact decisions to use an external program and also what indicators influence successful program implementation. The effects of central office support for a program, staff training, and ample funding are administrative factors to be examined before a program is selected.

Method. The research was conducted across several school districts within Indiana. Data collection involved the distribution of a questionnaire developed for this study. Schooladministrators comprised …

Chronic Estrogen-Induced Alterations In Adrenocorticotropin And Corticosterone Secretion: Relationship To Mineralocorticoid And Glucocorticoid Receptor Regulation In The Female Rat Anterior Pituitary Gland And Brain, Loyd H. Burgess

Dissertations

No abstract provided.

Effects Of Dopamine And Dopaminergic Agents On Neuronal Activity Of The Ventral Pallidum/Substantia Innominata, Renata J. Maslowski-Cobuzzi

Dissertations

No abstract provided.

A Continuous Culture Model To Examine Factors That Affect Transduction Among Pseudomonas Aeruginosa, Jean Replicon

Dissertations

No abstract provided.