A direct liquid injection (DLI) metalorganic chemical vapor deposition (MOCVD) technique was devised to deposit ferroelectric lead zirconate titanate (PZT) films for the first time. By utilizing a cheap DLI precursor delivery system, the problems encountered in the conventional precursor delivery system by bubblers were eliminated. Highly uniform PZT films with a spatial variation in film composition of less than ± 3.0% were grown along a range of an 8 cm long substrate holder. The composition and thickness variation within 4 runs was less than ± 5% and ± 8%, respectively. The linear relationship between the composition in precursor solution and in PZT films makes the composition control very easy for the process of DLI-MOCVD preparation of PZT films. The growth temperature had the largest effect on various properties of deposited PZT films. PZT films with (111) orientation were easily deposited at a higher growth temperature while at a low growth temperature, PZT films with (001) orientation tended to form. The effect of annealing on the top electrodes was observed to have the hysterisis loop symmetric and to reduce the leakage current of PZT films. The present DLI-MOCVD grown PZT films showed good ferroelectric properties. Two-remanent polarization from 20 to 50 µC/cm² and two-coercive field from 60 to 100 Kv/cm can be easily obtained from these PZT films which have the thickness range from 300 nm to 1000 nm. The remanent polarization was affected by Lanthanum doping, which decreased from 25µC/cm² at 0% La doping to 12µC/cm² at 8% La doping. No obvious effects on the coercive field and the morphology were observed within these La doping ranges. The leakage current density of our PZT films was decreased as the growth temperature reduced. By reducing the growth temperature from 640°C to 590°C, the leakage current density was reduced one order of magnitude to 5 x 10⁻⁸ A/cm² at an electrical field of 100 Kv/cm. These films also showed high dielectric constants, about 700 for PLZT (4/34/66) and about 1200 for PLZT (4/55/45). The dissipation factors, tan 𝜕, for the above films were 0.023 and 0.03, respectively. The electrical fatigue of the typical PZT films showed 70% switched polarization remained after 10¹⁰ cycles. Surface etching by Ar ion bombardment and H-tetramethylheptadione or H(thd) was applied to get rid of possible PbO which is electrical conducting on the PZT films. No improvement on the leakage current of PZT films was observed. Lead excess from -25% to -10% in the precursor solution was found to produce the PZT films with the strongest (111) orientation and surface flatness. However the best electrical properties were only found in the lead concentration range of -10% to 10% in the precursor solution. PbO may not be the reason for the leakage current of the PZT films. Optical microscopy observation showed that gas phase reaction at higher growth temperature may be the reason for the leakage current of the PZT films. Both the leakage current and morphology were improved obviously by reducing the growth temperature. The non-homogeneous grains of the PZT films may be the other reason to lead the leakage current of our PZT films. Both stochiometry and non-stochiometry two-step-grown PZT films have shown significant improvement in the homogeneity of the grains of PZT films, which should have low leakage current. / Master of Science

Isotactic polypropylene (PP) was reinforced with Vectra B950 (VB), a thermotropic liquid crystalline polymer (TLCP), in two novel fiber spinning processes. In one process, a single VB melt stream was surrounded by a sheath of PP in a manner comparable to a wire coating process just prior to melt spinning to generate fibers possessing a sheath-core structure. The other process involved the distribution of continuous VB melt streams within a separately plasticated PP melt to form a composite melt which was drawn to create matrix-fibril fibers consisting of a PP matrix in situ reinforced with VB fibrils. Both processes allow polymers with non-overlapping processing temperatures to be combined and melt spun to form composite fibers. The effect of fiber draw ratio on the tensile mechanical properties was assessed for composite fibers reinforced with 50 wt.% (39 vol.%) VB. Numerical simulations of the non-isothermal fiber drawing processes and an investigation of fiber morphology were undertaken in order to explain the mechanical properties. The matrix-fibril (in situ) reinforced fibers were woven into fabric preforms. The preforms, pre-wetted with PP, were used to fabricate orthotropic composites, and the mechanical performance and formability of these composites was evaluated. / Master of Science

The purpose of the study was to compare certain hemodynamic and electrocardiographic effects of incremental doses of arbutamine(ESA), a new beta-agonist pharmacologic stress agent, with exercise(ETT). Ten volunteers, mean age 66 years, with known or suspected coronary artery disease completed a symptom-limited ESA and ETT(modified Naughton protocol) to 85% of their age predicted maximum heart rate (APMHR) in a randomized cross-over study design. The ESA delivery system controlled infusion via an intravenous line to increase the subject's heart rate by 8 bt*min⁻¹. Heart rate(HR), systolic blood pressure(SBP), diastolic blood pressure (DBP), rate pressure product (RPP), and both an average of 3 independent observers visual ST segment shifts at J₆₀(VAVEST60) and computer ST segment shifts at J₆₀(CST60) were analyzed from the electrocardiogram(ECG) at baseline(0%TT), 25%TT, 50%TT, 75%TT, and at peak stress(100%TT). The occurrence and character of any dysrhythmias also were noted. Two-way repeated measures analysis of variance for each cardiovascular and electrocardiographic variable demonstrated no difference(p<0.05) by treatment effect alone. All variables, HR, SBP, DBP, RPP, VAVEST60, and CST60, showed a Significant (p<0.05) time effect while only SBP and RPP showed a significant (p≤0.01) time*treatment interaction effect. The following ectopic occurrences were noted during the ESA: PAC (n=4), PVC(n=3), couplet(n=2), and VT(n=5). The ETT produced a PAC(n=1), PVC's(n=3), and a couplet(n=1). The ESA produced a similar ST shift pattern in the ECG responses as did the ETT, however, it did this at a lower myocardial demand with a greater tendency for arrhythmias. These findings suggest a possible difference in receptor stimulation. The Similarities to exercise in the response variables measured in this study offer arbutamine as an alternative mode of stressing the heart for patient populations with multiple health limitations who could not perform an adequate exercise test. / Master of Science

Wastewaters from textile dyeing and finishing industries are often high in color, organic matter, metals and toxicity. Treatment is usually required before discharge into a sewer or body of water. Pretreatment often consists of chemical coagulation to remove color and solid matter. Aerobic biological treatment is incorporated to remove degradable organic matter and additional color and solid matter. The wastewater studied in this research project consisted of thermosol dye, print, and bleach and finish waste streams. The goal of this research project was to continue work on this wastewater that was initiated by Weber (1994). Pretreatment experiments were performed on the bleach and finish stream in an attempt to reduce organic content. Also, bench scale, aerobic biological reactors were operated at hydraulic residence times (HRT) of 4 and 7 days, to determine if higher reductions in color, organic matter or solids would be seen compared to Weber’s results from the 3 day HRT operation. Toxicity tests were performed on reactor effluents to determine if toxicity remained after treatment was performed. The bleach and finish did not respond favorably to the majority of pretreatments. An 84% color reduction was produced with adjustment of the pH to 4.5 and chemical coagulation with 400 mg/L of a blend of inorganic aluminum and a polyamine (AL220; Polymer Systems, Inc.). A 65% reduction in COD resulted from coagulation using 100 mg/L of Nalco polymer 9764, a polyamine. The bench scale reactors were-operated at sludge ages of 15, 20 and 30 days and hydraulic residence times of 4 and 7 days. The 4 day HRT COD removal results were similar to Weber’s (1994) results, while the 7 day HRT operation resulted in COD removals of 89 to 92%. Analysis of the steady state data produced kinetic coefficient values K₆, k, Y and k𝖽 for the 7 day operation of 2.6 mg/L, 0.16 day⁻¹, 0.74, and 0.05 day⁻¹. Toxicity tests performed on effluent from the 7 day HRT operations were passed. Short term chronic tests, using Pimephales promelus, resulted in No Observed Effect Concentrations of 100%. Acute tests, using Ceriodaphnia dubia, yielded LC50 values of greater than or equal to 100%. / Master of Science

Estimates of the social benefits of integrated pest management (IPM) are fundamental to an informed assessment of the value of public expenditures for IPM research and extension. This study evaluates a subset of the potential social benefits if IPM adoption - reductions in the environmental and human health costs of pesticide use. A methodology is developed to estimate the environmental and human health costs of pesticide use associated with the production of any crop. The cost estimates for production under "conventional" (i.e. non-IPM) pest management are compared to the cost estimates associated with production under an IPM program to generate estimates of the environmental and human health benefits of IPM adoption. The development of the methodology resulted in: (1) a new algorithm for assigning levels of IPM adoption to agricultural producers; (2) the design and administration of a contingent valuation survey to estimate society's willingness to pay (WTP) to avoid pesticide related risks to the environment and human health; (3) a new technique for detecting payment vehicle bias in contingent valuation surveys; (4) a set of criteria for assigning to pesticidal active ingredients (a.i.) levels of relative risk that a. i. 's pose to eight environmental and human health categories; and (5) the assignment of relative risk levels to more than one hundred pesticidal active ingredients. All of these results are directly applicable to other studies of this kind. The analysis of Virginia apple production results in several recommendations regarding the design of future chemical use surveys conducted by United States Department of Agriculture. The analysis of the Early Leaf Spot Advisory system (ELSA) for Virginia peanut production estimates the environmental and human health benefits of ELSA to be approximately $840,000 per year. / Master of Science

The purpose of my study is to contribute to our understanding of the complex ways in which race/ethnicity, class, gender and legal status intersect to shape the experiences of wife abuse among women. In this study, I analyze the experiences of one group of abused women -- Indian women in the U.S. I examine how Indian women's experience of abuse, and their reaction to it is shaped by the patriarchal gender relations within the family, as well as by their class status, their legal status, and their status as a minority racial/ethnic group in the U.S. I also examine Indian women's strategies of accommodation, negotiation and resistance to abuse. / Master of Science

This study focuses on the U.S. policy of conditioning China's Most-FavoredNation (MFN) status on its intellectual property protection in the 1991-1993 period. It seeks to evaluate the importance of U.S. foreign policy interests, societal actors, institutions (the presidency or Congress), and the interaction between these institutions in the MFN decisionmaking process. By applying three conceptual models -- the rational actor model, the interest group model, and the interbranch politics model -- to the three distinct phases in the development of the MFN-IPR policy, this study finds that it is most useful to combine the international explanation with one stressing domestic rules and institutions. Although U.S. strategic interests define the boundary of China policy and provide a justification of why the United States would continue to grant MFN status to China, MFN policy formulation has also been a function of U.S. domestic political process. With the diversification of China policy objectives and the pluralization of the policymaking process, U.S. strategic interests are frequently weighted and balanced by concerned governmental and societal institutions in the process, and are eventually reconciled with various political preferences to shape foreign policy outcomes. By breaking down the concept of a unitary state actor in the foreign policymaking process and unpacking the "black box" of domestic politics, the interest group model and the interbranch politics model allow us to see how domestic actors and institutions could serve to modify U.S. response to systemic conditions. They are useful supplements to the rational actor model in explaining the U.S. policy of conditional MFN. / Master of Arts

A method for chordwise redistribution of lift over a wing for poststall flight simulation is investigated. Aerofoil section moment data is used to divide and distribute into two parts the wing lifting line of Prandtl finite wing circulation theory. The method of lift distribution is applied in the aerodynamic package of a six degree-of-freedom flight simulator. The aerodynamic are computed with a nonlinear lifting line method which includes unsteady wake effects due to a discrete, nonplanar vortex system. The fidelity and vortex distribution of the wake is made adjustable under the constraint that the vortex distribution on the surface of the wing provide the same two dimensional angle of attack as did a single bound lifting line. The simulation is that of an actual general aviation aircraft. The wing lifting surface is modeled using the two lifting lines developed here, while the tail lifting surfaces are modeled by a single lifting line and associated control points. The simulation aircraft is “flown” through a prescribed maneuver by integrating the equations of motion. Results for the two lifting line system showed lateral responses in better agreement, over a single lifting line, with full scale flight tests. A form of the Kutta-Joukowski equation that relates circulation to pitching moment is also presented. / Master of Science

The study of Great Power behavior is a relevant and timeless pursuit, as the major powers can impact economies, societies, and lives around the world. Be it war, trade, or other assertions of interests abroad, such activities affect the global political landscape significantly. Important questions raised in the current literature revolve around issues such as: Why do Great Powers overexpand? And why do they expand at some points in time but not in others? This study asks, Why does a power expand differently in two similar situations at the same point in time? To probe such a question I explore McKinley's policy choices toward Cuba and the Philippines in 1898, the latter territory being annexed while the former not. Each case is presented against three competing explanations derived from recent expansionist literature. Propositions from each perspective--offensive realism, defensive realism and domestic coalition logrolling--are introduced in a structured, focused manner in each case. Despite the shortcomings of realism as a progressive paradigm for international relations inquiry, this study hints that a variant of realism-- offensive--could be a persuasive "first cut" theory at understanding foreign policy expansionism. At least, it is not apparent here that realism should be displaced by a domestic politics paradigm. Practically, what follows reveals the ability of Great Powers to expand 1s not necessarily thwarted due to internal characteristics (democratic, pluralist, "weak" state), whether they have popular support or not. The findings also suggest that it is out of confidence and opportunity that expansionism occurs in these cases, rather than out of insecurity. / Master of Arts

A simulated driving experiment was conducted to assess the potential benefits of using an auditory prompt to assist in target acquisition of in-vehicle navigational information, presented as a secondary task in commercial truck cab noise. Dual-task (driving in addition to performing a secondary task) and secondary task scenarios were presented, and acquisition time and accuracy on the secondary task were measured under three prompt types, three levels of information density, and three noise types. A subjective workload rating was also obtained from participants following each unique treatment condition. Accuracy was significantly higher for both auditory prompt types as compared to visual prompts under the dual-task configuration, but not significantly different under the secondary task configuration, suggesting that the increased visual demand of the primary task affected performance during the visual-only trials, but not during the trials in which prompts were presented auditorially. Under all levels of information density in the secondary task scenarios, acquisition time was significantly faster for the trials during which information was presented using the auditory-directional prompt, compared with the auditory-diotic and visual trials, suggesting that the aural lateralization cues helped drivers locate information more quickly. The techniques explored in the study have resulted in the benefit of presenting information more efficiently to a driver experiencing a high degree of visual workload. The potential exists to expand upon these findings, toward the goal of improving information display techniques which minimize the inherent visual burden with which many commercial truck drivers must contend. / Master of Science