Analytical and experimental research into the seismic response of four-bolt extended moment end-plate connections was conducted. Full-scale connections, ranging in size from moderate to large, were designed, fabricated and tested under cyclic loading until connection failure was observed. The design procedures for minimum end-plate thickness were developed from yield-line theory with prying forces included in the bolt tension forces. Stiffened end-plates, four-bolt wide connections and shimmed end-plate connections were valiations of the four-bolt connection tested. A325 and A490 bolts with internal strain gauges were employed to record and analyze bolt tension forces. Test results demonstrate that the design approach is satisfactory, but several aspects of connection response not previously observed nor reported were encountered. When weld access holes were present in an extended end-plate connection, excessive 3-D stresses developed in the hole region, causing a brittle fracture of the beam flange. In the absence of weld access holes, ductile failure occurred, evidenced by local buckling of the beam flanges and plastic hinge formation. These two responses or failures were exhibited by all connection sizes. The use of end-plate stifieners appeared to provide sufficient stress reduction, as ductile failures were observed in all stiffened, extended end-plate connection tests with weld access holes. Grade 50 steel, four-bolt end-plate connections with built-up beam sections were also tested and demonstrated that inadequate weld strength exists in the beam web-toflange welds. Prior to fracture in these welds, the connections responded in a ductile manner with local beam flange buckling. In conjunction with the full-scale testing, finite element models were created for several connection sizes. When actual material properties of the steel and bolts were modeled, an excellent correlation of test data and the model was noted. When weld access holes were introduced in the models, an increase of flange strain in the hole region was noted. Although not conclusive nor comprehensive for every connection configuration, the four-bolt design appears satisfactory to survive seismic activity. Further research should provide answers to other configurations and eventually provide an acceptable alternative beam-to-column connection for high seismic areas. / Ph. D.

The purpose of the present study was to investigate the effect of amount of performance information (API) and discrepant self-appraisal information on the modification of supervisor's original performance ratings. Confidence in original ratings was expected to mediate the relationship between API and modification of ratings after begin presented with discrepant self-appraisal information. The results indicated that AP! was not related to modification of original ratings. Moreover, API was unrelated to confidence in original ratings. However, as expected there was a negative relationship between confidence and modification of ratings, although the correlation was not significant. Additional analyses indicated that supervisors in the low API condition became more confident in their final performance ratings after viewing self-ratings than those in the high API condition. The implications of the findings of this study are discussed. / Ph. D.

This qualitative case study explored a professional development project designed to support teacher learning. A group of teachers and instructional supervisors met regularly for an academic year to create alternative assessment practices for the elementary classroom. The team of instructional supervisors planned and led meetings that encouraged the development of knowledge through interaction among teachers and reflections on classroom practice. In the study I explored the following questions: a) What were the actions of the instructional supervisors as they planned and worked with teachers? b) How did teachers interact within the environment designed for the social construction of knowledge? c) What actions created ambiguity for the participants and what actions accommodated the ambiguity? d) How does knowledge I constructed through this research enhance my practice as a teacher educator? The theoretical frame for this study was grounded in the work of researchers such as Dewey (1904), Vygotsky (1978, 1981), Lave & Wenger (1991), Rogoff (1990), and Short and Burke (1991) who suggested a social constructive perspective on knowledge. These researchers argued that knowledge is constructed through interactions among individuals. The interaction involves a process that is both dynamic and fluid. Through this process knowledge is constructed and reconstructed. Subsequently, the participants take more control over their thinking and their actions within the practice. Materials that were gathered and interpreted for this study were accumulated over the period of a school year from September 1993 through June 1994. They included fieldnotes from sessions with the teachers, transcriptions of audio recordings of interviews with the teachers, transcriptions of audio recordings of planning meetings with the instructional supervisors, analytical notes on the research process, anda research journal. Analysis of materials was a continuous process that began with the writing of analytical notes during the transcription process. I identified major themes from the collected materials and selected the theme of ambiguity as an important theme for understanding the nature of the environments studied. I wrote descriptions of both the learning environment created for the teachers and the planning sessions conducted by the team of supervisors. I described the role ambiguity played in the project and how the instructional supervisors and the teachers accommodated ambiguity. As a result of my research I developed several meaningful insights; through working with the planning team members I developed an appreciation for the complexity of organizing a transactional process in order to accommodate teachers' inquiry. Within the sessions with the teachers I recognized how the providing of opportunities for conversation enhanced interactions. I came to appreciate the complex nature of ambiguity as I understood how ambiguity is a part of the learning process. However, it is important to develop and then implement processes to accommodate ambiguity before that ambiguity reaches a critical point. If one does so then the participants in the learning environment are not overwhelmed. If the ambiguity is accommodated within the environment then the participants are encouraged to seek out multiple perspectives. / Ph. D.

Although compaction and sintering of polymeric powders has been investigated since the early 1970's, this processing method is not widely used, possibly because the fundamental mechanisms which control compaction and sintering have never been fully understood. This study has made significant contributions to our understanding of compaction and sintering of polymers. It was demonstrated that mechanical properties (yield strength, modulus) and physical characteristics (degree of physical aging, glass transition temperature, presence of crystallinity) of the particles, and thus, powder processing, storage, and handling techniques, affect the ability of the polymer to be successfully compacted. The difficulties encountered in sintering polymeric compacts were explained in terms of a loss of configurational entropy of the polymer molecules during compaction, which caused large-scale dimensional recovery in the particles upon heating above T g. Hot compaction (above room temperature, but below Tg) was not found to be useful in eliminating recovery during pressureless sintering. However, consolidation of compacts formed at room temperature (by heating 10-20°C above T g and applying a small pressure (less than 50 kPa» was shown to be a promising processing method. / Ph. D.

Few tests are available for the investigation of emotional learning. The purpose of the present study was to create and provide initial data on the utility of affective list alternatives for the well known Rey Auditory Verbal Learning Test (RAVL). Results suggest that all lists (positive, negative, neutral) exhibited a Similar acquisition pattern and overall primacy effect. The purpose of the present study was to assess the utility of the AAVL in the production of peripheral arousal and cerebral asymmetry correlates of emotion. Experiment 1 assessed the utility of the AAVL in the induction of physiological arousal. Sixty-three right-handed male undergraduates participated in the study. It was anticipated that affective verbal learning would lead to arousal patterns characteristic of different emotions (Izard, 1977), with significant increases in blood pressure following negative list learning and significant decreases following positive list learning. Since blood pressure increased Significantly following the learning of negatively valenced words and decreased significantly following the learning of positively valenced words, this was supported. Experiment 2 assessed the influence of the AAVL on functional cerebral asymmetry using a dichotic listening paradigm. Sixty-three right-handed male undergraduates took part in the experiment. It was anticipated that the negative list would prime right cerebral systems, resulting in heightened left ear identification of sad or angry tones of voice. The positive list was predicted to prime left cerebral systems, resulting in subsequently heightened identification of happy or neutral tones of voice at the right ear. This hypothesis was not supported. The identification of tone of voice was significantly better with left ear (right hemisphere) presentations than with right ear presentations for the identification of sad and angry valences. In partial replication of Bryden and MacRae (1989), the identification of dichotically presented tones of voice also improved with practice across the two blocks of trials for the identification of angry tones of voice. The AAVL provides an objective measure of emotional learning. Given the abundance of research on lateral asymmetries in emotional and verbal processing, the AAVL may provide an objective means for evaluating individual differences in affective verbal learning and potentially provide a tool for assessment of cerebral dysfunction in the clinic or in the assessment of affective disorders. / Ph. D.

New applications of capillary zone electrophoresis (CZE) are explored. These include condensation polymer compositional analysis (1,2,3), drug in urine analysis (4) and nonaqueous CE (5) by using a mixture of N Methylformamide (NMF) and dimethylsulfoxide (DMSO). First, the application of CZE to polyimide compositional analysis is described. The electropherograms of decomposed products from polyimide are determined by the structure of monomers from which a polyimide is made. In most cases, it is difficult to know structures for all peaks that appear in the electropherogram. But different polyimides give different patterns on the electropherogram and the same monomer in different polyimides gives a similar pattern. This pattern of electropherogram can be considered as a "fingerprint" of the polyimide, just as a chromatogram obtained from pyrolysis GC analysis of a polymer. It is possible to deduce the major components of the polyimide from the pattern of the electropherogram of the decomposition products of the polyimide. Second, the application of CZE to nylon compositional analysis is studied. The hydrolysis of nylon in acidic condition gives its corresponding monomer. There is no further decomposition reaction of the monomer. This method is simple and easy. Analysis of trace amount amine impurities is possible, which is very difficult to do by other methods. Third, a method for ranitidine, an ulcer disease, in urine is developed. Solid phase extraction conditions and the CZE procedure conditions are optimized. Experimental results show that good recovery of the drug from a urine sample and relatively good reproducibility are obtained. Finally, non-aqueous CE using a mixture of NMF and DMSO as solvent is studied. The separation of a mixture of aromatic acids by this solvent is described. / Ph. D.

The purpose of this descriptive investigation was to determine the effectiveness of the Ed.D. Program in Educational Administration at Virginia Polytechnic Institute and State University as perceived by its graduates. Surveys returned by graduates were analyzed for the purposes of determining whether the program was effective in preparing them to perform administrative tasks, whether the program assisted in career advancement and if the program was not effective, how could it have been improved. The results overwhelmingly indicated graduates perceived the program as effective. They indicated the program broadened their perspectives and provided knowledge that helped them become agents of change in educational administration. Graduates indicated achieving the degree provided them with a high level of personal satisfaction and accomplishment. The Ed.D. Administration Degree enhanced their chances for career advancement. Graduates who did not experience career advancement indicated the degree served them well by increasing their knowledge in the field. The Ed.D. Administration faculty were praised highly and were referred to as Educational "trend setters." The Ed.D. Administration degree has become the "degree" to have in Virginia as indicated by graduates of the program. Results of the study led to recommendations that the caliber of graduates remain high; use professors from Blacksburg to maintain high caliber of instruction; program flexibility should remain so that candidates who are not a part of a cohort group may enter the program at different stages; continue to seek diversity in students and staff; maintain status of College of Education; and finally, College of Education should continue to prepare Educational Leaders and should not merge with any other college at Virginia Polytechnic Institute and State University. / Ph. D.

Accurate numerical algorithms for solving systems of nonlinear hyperbolic equations are considered. The issues of the capturing and the non-diffusive resolution of contact discontinuities were investigated using two different approaches: a kinetic fluctuation splitting scheme and a discontinuity confinement scheme based on an antidiffusion approach. In both approaches cell-vertex fluctuation-splitting methods are used in order to generate a multi-dimensional procedure. The kinetic fluctuation-splitting scheme presented here is a Boltzmann type scheme based on an LDA-scheme discretization on a triangulated Cartesian mesh that uses diagonal adaptive strategy. The LDA scheme developed by Struijs, Deconinck and Roe has the property of being second-order accurate and linear for a scalar advection equation. It is implemented for the Boltzmann equation following the work of Eppard and Grossman and completes the series of multi-dimensional Euler solvers with upwinding applied at the kinetic level. The MKFS-LDA scheme is a cell-vertex scheme. It was obtained by taking the moments of the fluctuation in the distribution function that are calculated according to the LDA fluctuation splitting procedure on a kinetic level. The diagonal-adaptive procedure designed by Eppard and Grossman for MKFS-NDA scheme was applied to eliminate the diagonal dependence. Results show improvement over lower-order N-scheme based solvers. Results for a simple oblique-shock reflection and a shear wave demonstrate that the adaptive procedure and the higher order low diffusion scheme provide sharper resolution than the dimensionally-split kinetic CIR scheme and the first order N-scheme. Moreover, no evidence of oscillations near discontinuities was observed but the order of accuracy is probably lower than the second-order theoretically predicted accuracy on regular meshes. Results for the inviscid reflection of an oblique shock wave and for an oblique shear wave indicate greatly improved resolution over first-order dimensionally-split approach. However, the complexity of the scheme and CPU usage increase were not justified by slight improvement over the first order N-scheme. In the second part a new discontinuity confinement procedure is described. It uses ideas developed by Steinhoff to capture concentrated vorticity layers and short acoustic pulses. The discontinuity confinement method not only captures contact discontinuities over a few grid cells but also safeguards them from numerical dissipation as they evolve with time and over long spatial distances. A one dimensional discontinuity confinement method in terms of flux correction was developed and applied to the Euler solver. The results for the shock tube problem and contact discontinuity propagation were encouraging but the extension to two dimensional problems was not possible in the flux correction framework. A new scheme was developed using a closely related antidiffusion convection and fluctuation splitting ideas used in vortex confinement method by Steinhoff. The new formulation provides a simple and multi-dimensional procedure that can be used with any monotone basic solver. A comparison of the dissipative property of the confinement scheme with a higher-order dimensionally split upwind scheme and several solutions on adaptive unstructured grids demonstrate that the new method has the ability to much more sharply resolve complex regions with contact discontinuities. Moreover, the quality of the solution does not deteriorate over many time iterations or long spatial distances. Solutions for several two-dimensional steady problems are presented to demonstrate the high resolution property of the new scheme. It includes oblique shear layer problem, triple point problem and underexpanded nozzle flow. Underexpanded nozzle flow involves complex interaction of free surface, shock waves and slip lines. Traditional high-order schemes smear the contact surfaces preventing accurate definition of the flow structure inside the jet. However, using a Cartesian grid and the discontinuity confinement procedure the free surface of the jet and slip lines were resolved within 3 grid cells. In the case of an oblique shear layer the new scheme demonstrated no degradation of the initial profile for the discontinuity. Robustness of the confinement scheme depends on the monotone basic solver and also multi-dimensional switch that excludes expansion regions from effect of the confinement. Research still needs to be done in order to develop a switch which can be used on a wide variety of applications. / Ph. D.

A comprehensive approach to soil P management in agricultural systems requires a balance between nutritional enhancement of the soil and a reduction in adverse consequences on the environment. Evaluation of forms in which P is present in the soil, dynamics of P transformation across these forms, determinants of spatial and temporal distribution of P pools in the soil, and impacts of agricultural practices on the rate and direction of these reactions were the key objectives of the present investigation. Phosphorus extracted by the four widely used soil extractants, i.e., Bray 1, Mehlich 1, Mehlich 3, and Olsen, represented less than 25 percent of the total P content in 43 Virginia soils from the Coastal Plain, Piedmont, and Ridge and Valley regions. Correlation between Bray 1 (1 minute and 5-minute shaking), Mehlich 1, and Mehlich 3 extractable P was high: correlation of these extractants was poor with the Olsen procedure which extracted the lowest soil P contents. The Mehlich 3 procedure was more reliable in the extraction of labile P than the Mehlich 1 procedure in soils with a wide range of pH values. The Mehlich 3 procedure was less prone to extraction of plant unavailable, structurally adsorbed phosphorus, particularly in dithionite-citrate-bicarbonate extractable Al₂O₃ rich soils, than the other procedures. The process of P extraction by different extractants under varying physical and chemical conditions was satisfactorily explained by an acid-catalyzed nucleophilic substitution reaction mechanism. This mechanism satisfactorily links the solubilization of P from Al and Fe surfaces to the strength of nucleophilic agents such as OH⁻, CH₃COO⁻, CI⁻, F⁻, and H₂O, and to the acidity of the supernatant solution. Inorganic P fractionation was determined by the modified Chang and Jackson (1957) procedure of Peterson and Corey (1966) with several modifications, and the organic P analyzed by the Bowman (1989) method. The total P content of the 43 soils in this study ranged from 0.02% to 0.4%. Twenty six percent of the total P was in the labile to moderately labile pool, 49% in the non-labile pool, and 25% in the organic fraction. The distribution pattern of Fe-P, reductant soluble P, occluded P, residual P, and organic P fractions was directly related to soil Fe₂O₃ and clay contents. The Al-P content was not markedly influenced by the clay content or pH. It was concluded that Fe-P, a dominant labile P form in agricultural soils was transformed over time to reductant soluble P, the dominant P form in the soils. The reductant soluble P fraction, which increases with P fertilization and has higher solubility under reduced conditions, through erosion poses a major potential eutrophication threat to surface waters. The eutrophication potential is high in the Piedmont and high clay soils. Phosphorus adsorption in the Davidson and Tatum soils from the Piedmont physiographic region was well explained by the two-site-Langmuir adsorption model. The adsorption maxima was slightly (5%) decreased by long-term P fertilization over three decades. All soil inorganic and organic P fractions were increased by fertilizer application with the reductant soluble fraction increasing by 61 and 57 percent in the Davidson and Tatum soils, respectively. The residual effects of long-term application of P fertilizer increased labile P contents extracted by soil test methods, and in the Davidson soil the uptake from the residual fertilizer P was sufficient to maintain the tissue P concentrations of young corn seedlings at the sufficiency range. / Ph. D.

In this work, we considered an “inverse-design” problem, where we specified the flow distribution in the computational domain or on its subset and sought the geometrical configuration that produced this flow. Based on this idea, we formulated a control problem, in which the optimization procedure minimizes the error between the target flow and the actual flow through successive adjustment of the design parameters. We were interested in exploring the computational efficiency of the numerical solution of this problem, particularly the implementation of workstation cluster environment to the solution of the control problem by employing numerical algorithms, which would allow coarse-grained parallelization. These aspects were studied with an example of one-dimensional heat transfer in surfaces of non-uniform cross-sectional area and the optimal design of a two-dimensional nozzle. We compared the computational cost and convergence properties of the optimization procedure for two approaches: the “Black-Box” method and domain decomposition method. When employing the “Black-Box” technique, the unconstrained control problem was solved in terms of the design variables and in the case of domain decomposition implementation, the constrained control problem was solved in terms of design variables and boundary data on interfaces. Also, we implemented the grid-embedding chimera technique to the solution of a one-dimensional heat transfer problem. The formulation of this scheme in terms of domain decomposition leads to an overlapping domain decomposition method. It was concluded from one-dimensional results that domain decomposition methods can be successfully incorporated into the optimization-based design framework. The original analysis problem can be split into problems on subdomains, which can be solved in parallel with data transfer at each step limited to exchanging boundary information between the neighboring subdomains and between the “master” processor. In the case of a two-dimensional flow, the optimization was applied to supersonic flow and the discontinuous flow. It was concluded, that if one wishes to implement this algorithm in a parallel environment, the computations should be spread between the processors in such a way, that the number of processors is proportional to the number of control variables. / Master of Science