The intent of this research was to enhance our knowledge of aqueous phenolformaldehyde resin cure as it is affected by the elevated water vapor pressures that occur during hot-pressing of a wood-based composite. Microdielectric spectroscopy (DEA) was used to monitor the cure reaction, and thermomechanical analysis (TMA), swelling tests and scanning electron microscopy (SEM) techniques were used to characterize the final resin-network. Microdielectric results showed that as the water vapor pressure of the sy stem increases the time to gelation increases. It was also found that the injection of saturated water vapor sharply decreased the gelation time when compared to the other water vapor environmental conditions. In addition, it was found that the higher the water vapor pressure the lower the residual ion viscosity. Thermomechanical analysis and swelling test experiments showed that as the water vapor pressure increases the glass transition temperature and the cross-link density of the cured resin-network decreases. Considerable differences in the morphology of the network were found using SEM. Thus, it can be established that during the curing process under elevated water vapor pressures of a liquid phenol-formaldehyde adhesive some water is trapped into the resin network and it is acting as a plasticizer. A theoretical approach to model the cure kinetics of phenol-formaldehyde has been developed. The model is based on the occurrence of two simultaneous processes (condensation polymerization and evaporation of water) and on the concentration dependency of the activation energy of polymerization. / Ph. D.

The synthesis of two types of Localized Wave (L W) pulses is considered; these are the 'Focus Wave Model (FWM) pulse and the X Wave pulse. First, we introduce the modified bidirectional representation where one can select new basis functions resulting in different representations for a solution to the scalar wave equation. Through this new representation, we find a new class of focused X Waves which can be extremely localized. The modified bidirectional decomposition is applied to the nonhomogeneous scalar wave equation, resulting in moving sources generating L W pulses. In this work, we also address the possibility of exciting L W pulses from dynamic apertures, or apertures the effective radius of which is varied with time. Ideal L W pulses cannot be realized because they require infinite time excitation. However, in the case of finite L W pulses, the aperture of excitation is finite and is varied from a time - T to T. We show that the resulting L W pulses are more resistant to decay than classical monochromatic Gaussian pulses occupying the same beam waist. Both types of finite L W pulses, such as the FWM and X Wave pulse, can propagate without significant decay to much greater distances than classical monochromatic pulses. This desirable behavior is attributed to the superior aperture efficiency of the L W pulses, which in turn is attributed to their unique spectral structure. / Ph. D.

A large-eddy simulation methodology (LES) has been developed for predicting the turbulent physics of an incompressible flow in simple and complex geometries. The Cartesian form of the governing equations was first verified, and then later used to investigate a three-dimensional shear-driven cavity flow. The investigation involved Reynolds numbers of 2000, 3200, 5000 and 10000 and focused on the unsteadiness and turbulent characteristics of the flow. At the low Reynolds numbers (Re ~ 5000) where the cavity flow is fully laminar, direct numerical simulations (DNS) were conducted whereas the LES methodology was adopted to predict the cavity flow at the higher Reynolds number (Re = 10000). Determining the parameters in the damped subgrid scale (SGS) turbulence model for this complex flow was guided by the DNS results at Re = 5000. The SGS model was also verified against DNS results at Re = 7500 where the cavity flow was known through laboratory experimentation to be locally transitional. The LES results using the damped SGS model verified the published experimental evidence as well as uncovered new flow features within the cavity. LES computations were also carried-out of the three-dimensional shear driven cavity flow at a high Reynolds number where the SGS turbulent field was represented by a dynamic model. Lilly's least-squares expression was tested for determining Smagorinsky's coefficient in the model without ad hoc measures such as ensemble-averaging or filtering. However, zero cutoff of negative total viscosity (kinematic plus turbulent eddy viscosity) was necessary to maintain stable solutions. A discretized filter function was derived for the test filter. Both qualitative and quantitative comparisons to experimental data show that the dynamic model performed quite well. The dynamic model gave better comparisons to the experimental evidence than the damped model did. Vortex formation in the wake of a circular cylinder and their subsequent downstream transport was also numerically investigated by LES. Here however, the curvilinear form of the governing equations was necessary to perform the computations. A new generalized dynamic model was derived to represent the SGS stress field in the curvilinear space. This new model introduced the contravariant velocity components as part of the field variables. New downstream boundary conditions were also formulated to permit the shed vortices to exit with minimum disturbance. The focus of the investigation was at Re = 5600 with some verification of the computations at Re = 200 and Re = 3000. At all of these Reynolds numbers. the upstream boundary layer was laminar but the wake was fully turbulent at Re = 3000 and Re = 5600. The LES results of the many interesting characteristics of the wake showed good comparisons to the experimental data. / Ph. D.

Sunshine and palmetto bass (different crosses of hybrid striped bass) were used to determine immunologic, hematologic and serum chemistry changes under different culture conditions. The kinetics of the humoral immune response was determined for sunshine bass acclimated to 10, 18, 24, 29°C, and to elevated ammonia (0.15 mg/L NH3) and elevated nitrate (200 mg/L). These conditions are frequently encountered in aquaculture situations. Cooler temperatures decreased both the magnitude and onset of the humoral response, being lowest at 10°C, intermediate at 18°C, the highest at 24 and 29°C. Elevated ammonia did not affect the immune response, while elevated nitrate decreased antibody production to the level of the 18°C response. Hematologic reference intervals were determined for sunshine bass in tanks and recirculating systems, and palmetto bass in tanks. Serum chemistry reference intervals were determined for sunshine bass in tanks, recirculating systems and cage systems. Greater differences were observed in reference intervals between the culture systems, than between the two types of hybrid. To determine if environmental factors influenced the differences seen in the reference, sunshine bass were acclimated to 10, 18, 24, 29°C, elevated ammonia (0.15 mg/L NH3) and elevated nitrate (200 mg/L). The hematology and serum chemistry profiles of these fish were compared with the reference intervals for sunshine bass in tanks. Leukocyte, lymphocyte and monocyte counts at 10°C, and glucose and calcium at 10 and 18°C deviated sufficiently to suggest generating separate reference intervals at these temperatures. In the nitrate treated fish, creatinine levels were elevated and chloride levels were lower than controls and outside the reference interval. These two responses were presumed to be pathologic changes associated with elevated nitrate levels due to the large deviation in the analytes and the mortalities seen in the nitrate treated fish. The remaining analytes for fish in the different environments were within or slightly outside the reference intervals. These slight changes were presumed to be due to individual variation as the reference intervals were determined for fish under relatively uniform conditions and may not be sufficiently broad to cover fish from more varied environments. With minor modification, the reference intervals should apply to sunshine bass in most situations. / Ph. D.

In this thesis, I examine the possibility of deriving a normative position and political stance from the theory of Michel Foucault. In an attempt to answer the question, "If power cannot be separated from knowledge, then how can one use knowledge to critique forms of power?" I analyze and judge the arguments against Foucault's perspective by Nancy Fraser and Jurgen Habermas. I argue that the criticisms made by each are incongruent with the position from which Foucault speaks and are the result of their own theoretical frameworks. I then problematize the frameworks of need interpretation and universal pragmatics that Fraser and Habermas, respectively, appeal to revealing the connection between their foundations and bio-power. Following this, I explore William Connolly's suggestion of "dialogical ethics" as a normative foundation for Foucault's suggestions concluding that this approach fails due to its ultimate appeal to an imaginary telos as justification. Rather, I suggest that Foucault's normativity rests in the desire to open up possibilities for being other than what we are and that this translates into a politics centered less on locating and overturning centers of power and more on local struggles against government and market intrusions into our lives. Nevertheless, I conclude that questions concerning the utility of Foucault's work for social theory are better answered not through metatheoretical discussions concerning it, but rather through genealogical analyses of sociohistorical phenomena that draw from it. / Master of Arts

Chlorine dioxide has gained much attention for use as a possible alternative disinfectant in water treatment plants due to concerns regarding trihalomethane formation in drinking waters which utilize chlorine as the primary disinfectant and the strict regulations regarding THM's and THMFP (MCL of 0.080 mg/L for TTHMs) (Pontius, 1993). Although the use of Cl02 as a disinfectant prevents the formation of THM's, concern exists regarding the potential health risks due to the disinfection-by-products of chlorite and chlorate. The main objective of this project was to study the removal of chlorite by reaction with ferrous iron under elevated pH conditions. The stoichiometry of the reaction was evaluated under the following conditions: solution pH of 6.0 to 10.0, 02(aq) concentration of 0.5 to 10 mg/L, and solution DOC concentrations of 0 to 15 mg/L. Mass balances were conducted to define the speciation of the oxychlorine residuals associated with the reduction of Cl02 by Fe(II). / Master of Science

The purpose of this study is to describe and analyze the behavior of the term structure of interest rates on a daily basis between January 2, 1980, and March 31, 1994, especially with respect to the synchronization and the relative amplitude of change of different maturities in the term structure. Results reveal a high degree of synchronization of the elements of the yield curve during this period. Volatility was found to vary inversely with maturity during this time. The characteristics seen in the daily term structure of this period are consistent with observations in prior studies, including a study of 1901-1954 annual data by Dr. David I. Meiselman and a study of 1955-1989 monthly data by Maj-Lis A. Voss. / Master of Arts

Men (N = 25) and women (N = 27} rated as either high or low in visuospatial ability as assessed on a battery of visuospatial tests (Card Rotations, Mental Rotations, Minnesota Paper Form Board), performed a computer-administered task requiring the mental rotation of abstract geometric shapes presented sequentially, either alone or with a concurrent task of repeating sets of six random digits. Gender and skill-level effects were found. Men were faster than women, and high visuospatial subjects were faster than low. Individual performance did not significantly differ between the single- and dual-task conditions, either in terms of mean response time or rate of mental rotation. This finding is counter to previous studies (Corballis, 1986; Kail, 1991) that found subjects performed slower overall in dual-task conditions, but did not differ in terms of rotation rate. Differences in group variability were also found; that is, women were more variable in response time and error rates than men, and lows were more variable than highs. The gender differences are interpreted in terms of variability; with the major finding that for rotation rate, intercept, and errors, only within the low visuospatial skill category did women perform poorer than men. Furthermore, only women in the low visuospatial skill group showed the classic mental rotation function of increasing response time with increasing angular disparity. / Master of Science

This thesis describes the development of the Voice Coding Development and Research (VoCoDeR) System, a software tool for testing and development of new speech coding methods. This tool enables a researcher to build a voice encoder and speech filters, determine an optimal bit allocation scheme, and/or create an error correction scheme, as desired. Using a channel simulation tool such as BERSIM, the user can create bit error patterns to corrupt the data and then decode the speech for playback and analysis. The system is based upon the North American Digital Cellular (NADC) 8kbps Vector-Sum Excited Linear Prediction (VSELP) speech coder and is currently capable of simulating the complete IS-54 source and channel coding scheme. The system is tested using Multi-Stage Vector Quantization and Finite-State Vector Quantization (FSVQ) applied to the linear prediction coefficients. FSVQ provides significant bit rate savings over previous methods of quantization. A variety of coefficient representations are compared including log-area ratios, arcsine reflection coefficients, line spectrum pairs and immittance spectrum pairs. This has allowed the recently introduced immittance spectrum pairs to be tested using vector quantization. Multiple distortion measures are also examined. The VoCoDeR System provides a tool that will allow an engineer to work on new speech coding algorithms or to determine an optimal source and channel coding scheme. / Master of Science

Much research has been accomplished on the effects of target motion on visual acuity. Research has also been accomplished on the effects of target orientation on visual acuity. The contrast sensitivity function (CSF) also has been studied as a predictor of visual performance under dynamic conditions. However, no previous studies have combined these areas of research and examined the effect of target orientation on the Dynamic Contrast Sensitivity Function (DCSF). This study examined the effects of target orientation on the DCSF and found that diagonal lines (relative to vertical lines) decreased the DCSF, on average over 19%. Previous research indicated that target motion reduces contrast sensitivity, and at the same time shifts the peak of the CSF toward lower spatial frequencies. This study rotated the target in a circular path (velocities of 22°, 30°, and 39°/second) and found a similar decrement and shift in the CSF. The main effects for Target Orientation, Velocity, and Spatial Frequency and their two-way interactions were all statistically significant (p ≤ .05). Additionally, all velocity conditions were found to be statistically different from each other. These results advance the validity of our measurement device and procedures. The effect of target orientation presumably is a function of the magnocellular and parvocellular visual pathway systems and their roles in the detection of form and motion. While the magnocellular system is primarily responsible for detection of motion and large objects, the parvocellular system is responsible for the detection of color and fine detail. / Master of Science