The objective of this study is to design a pultrusion die with a desired temperature profile. Design optimization programs were developed to synthesize the number of cartridge heaters, power input and location of each cartridge heater for a laboratory-scale pultrusion die. This is the first step in developing a pultrusion control process. Before this can be done, a thorough understanding of the pultrusion process is required. The parameters investigated are fiber-resin mixture, degree of curing, production temperature profile and pulling speed. It was found that these parameters are interrelated. / Master of Science

A study was conducted to investigate the effect ofspray drying on concentration of sulfamethazine (SMZ) in fluid milk dried to powder «10% moisture). Antibiotic-free skim and whole (homogenized) milk were spiked at 5, 10, 50 and 100 ppb sulfamethazine levels, pasteurized and stored at 4°C till further processed. All samples were spray dried at an inlet temperature of 180 ± 2°C and outlet temperature of 100 ± 2°C and stored at -20°C until analyzed. Sulfamethazine concentration was determined quantitatively by HPLC, a microbial receptor assay (Charm-II®) and an ELISA assay (LacTek®) and qualitatively by an ELISA method (Cite®) in milk samples before and after spray drying. Dry milk samples were reconstituted (10% w/w) for all analyses. statistical determination of significant differences (p = 0.05) between fluid and dry milk samples and whole and skim milk sample~was completed by paired t-tests. Sulfamethazine concentrations increased 81.4% and 84.1% in skim and whole milk respectively at 100 ppb spiked level but were lower than expected increase of 88-91% based on their total solids for whole and skim milk as obtained by modified FDA HPLC method. At lower levels of 5 and 10 ppb, the HPLC method was not sensitive enough to provide usable data. Increase in sulfamethazine concentration from fluid to dry milk was also determined by· Charm-II® and LacTek® techniques. Poor recoveries and variability in data were evident due to binding of sulfamethazine to undetermined milk components as a result of processing and storage also due to break-down of sulfamethazine (mp = 176°C) at 1S00C during spray drying. Sulfamethazine 163 ppb by LacTek® and 94.6 ppb by Charm-II® (at a spiked level of 10 ppb fluid milk) was successfully removed from dried milk after 120 min using supercritical CO₂ (pressure = 5500 psi, 50 0 C / Master of Science

Lightweight (Ca,Mg)Zr₄(PO₄)₆(CMZP) ceramics have been fabricated with relative densities (P_lightweight/p_dense) of less than 0.35 by the polymer foam technique, and higher than 0.35 by the polymer powder technique. The polymer powder method forms an inhomogeneous pore structure having average pore sizes of 30-80 μm compared with the polymer foam method, which yields a large and uniform pore structures with pores 250-300 μm in diameter. The thermal expansion of the lightweight CMZP ceramics varies from positive (+2.7x1 0⁻⁶/â C) to negative (-2.6x10⁻⁶/ â C) with increasing grain size. The lightweight CMZP ceramics exhibit an excellent thermal shock resistance and this resistance is improved by increasing porosity. Mechanical properties including tensile strength, compressive strength, Modulus of rupture (MOR), and Young's moduli have been determined and vary exponentially with porosity. The strengths of the lightweight CMZP ceramics are superior to those of lightweight Zr0₂ with the same bulk density. Young's moduli, which were determined using a sonic velocity technique, range from about 5 GPa to 30 GPa, depending on the composition and the relative density. Furthermore, corrosion studies show that lightweight CMZP ceramics possess high resistance to acid corrosion at ambient temperature. / Master of Science

Not available until OCRd / Master of Science

The exact mechanisms controlling uterine secretion of prostaglandin F₂α (PGF₂α) are not known. This study (Experiments 1, 2 and 3) was conducted to evaluate the relationships of progesterone and estrogen to changes in 13,14-dihydro-15-keto-prostaglandin F₂α (PGFM) and PGF₂α in ewes. Experiment 1 was designed to determine whether a radioimmunoassay (RIA) for progesterone would detect pessary-released 6α-methyl-17α-hydroxy-progesterone (MPA; n=3) and oral 17α-acetoxy-6-methyl-16-methylene-4, 6-pregnadiene-3, 20 dione (MGA; n=3) in blood plasma of ovariectomized ewes. Neither progestogen treatment interfered with the RIA. Experiment 2 was conducted to answer the question: Do MPA-containing pessaries delay luteolysis in intact ewes? Ewes were treated with MPA containing (n=10) or blank pessaries (controls; n=8) from d 7 and until d 18 of the estrous cycle for control and until d 22 for MPA-treated ewes; d 0 was the day of estrus. Blood samples were collected from the jugular vein throughout the experiment. Pessaries containing MPA did not affect the timing of luteolysis (d 15.4 ± .2), but they prolonged (P<.O5) the interestrous interval (17.5 d for control vs 24.1 d for MPA-treated ewes). Experiment 3 was designed to study the relationships among progesterone, estrogen, PGFM and PGF₂α in ewes. Ewes were treated with MPA-containing (n=7; 60 mg), progesterone-containing (n=8i 45 mg) or blank pessaries (n=8) from d 7 until d 20 of the estrous cycle. From d 14 and continuing until 24 h after estrus, jugular and vena caval blood samples were collected during two sampling periods daily. Plasma was assayed for progesterone, estrogen, PGFM and PGF₂α. Treatment did not affect the profiles of change in concentration of progesterone, PGFM and jugular PGF₂α, but treatment affected (P < .05) estrogen and vena caval PGF₂α profiles. Overall, treatment affected (P < .05) the mean concentrations of estrogen, progesterone, PGFM and PGF₂α. sampling site (jugular vs. vena cava) affected (P < .0001) the mean concentration of progesterone, estrogen and PGF₂α, but site did not affect PGFM concentrations. Hormonal relationships associated with changes in release of PGF₂α were evaluated. Estrogen seemed to be the primary hormone controlling PGF₂α release. In conclusion, MPA treatment did not delay the timing of luteolysis, but it increased the interestrous interval. Of the compounds measured, estrogen accounted for the greatest proportion of the variation in PGF₂α release in ewes around the time of luteolysis. / Master of Science

not OCRd / Master of Science

In this thesis, the proof-mass actuator is studied for vibration suppression of a flexible structure. While these actuators have a favorable force-to-weight ratio, the finite travel of the proof-mass, called the stroke length, imposes restrictions on the use of the actuator. This restriction implies that the actuator has a finite operating region in terms of initial conditions on the state. This operating region, along with the amount of vibration suppression potential, defines the performance of the actuator. To increase the performance, nonlinear control is proposed. These control laws monitor the position and velocity of the proof-mass and apply a large restoring force whenever the proof-mass is in danger of breaking its stroke limit. A harmonic balance analysis concludes that these nonlinear control laws do not induce limit cycles. The performance of actuators with different parameters is also compared. A relation is presented that associates the modal frequency of the structure to these parameters. It is also found that large stroke with small mass offers the best performance with the nonlinear control in place. / Master of Science

The optimal projection approach to solving the reduced order model problem produces two coupled, highly nonlinear matrix equations with rank conditions as constraints. Due to the resemblance of these equations to standard matrix Lyapunov equations, they are called modified Lyapunov equations. The proposed algorithms utilize probability-one homotopy theory as the main tool. It is shown that there is a family of systems (the homotopy) that make a continuous transformation from some initial system to the final system. With a carefully chosen initial problem a theorem guarantees that all the systems along the homotopy path will be asymptotically stable, controllable and observable. One method, which solves the equations in their original form, requires a decomposition of the projection matrix using the Drazin inverse of a matrix. It is shown that the appropriate inverse is a differentiable function. An effective algorithm for computing the derivative of the projection matrix that involves solving a set of Sylvester equations is given. Another class of methods considers the equations in a modified form, using a decomposition of the pseudogramians based on a contragredient transformation. Some freedom is left in making an exact match between the number of equations and the number of unknowns, thus effectively generating a family of methods. Three strategies are considered for balancing the number of equations and unknowns. This approach proved to be very successful on a number of examples. The tests have shown that using the ‘best’ method practically always leads to a solution. / Master of Science

Anolis carolinensis was found to have three stereotyped and distinct territorial headbob patterns, referred to as Types A, B, and C. Each type had two variants, one in which the dewlap appeared mid-display and a second in which dewlap extension was absent. Use of these signals was examined in two contexts: a "male-alone” or advertisement context and a "male-male" or aggressive context. Context accounted for only minor amounts of the variability while display type explained the majority of unit variability. Display rate in advertisement was 0.3 displays/ min, half the displays were solitary, and half occurred in volleys of 2-6 displays. Dewlap extension accompanied 97% of the displays, and all three types of displays were used. Display rate was eightfold greater in male-male context, and the rate doubled again as males came within 20 cm of each other. At large separation distances (>60 cm), long volleys (4-9 displays) were common, Type C displays predominated, and dewlap extension accompanied 92% of the displays. At smaller separation distances (<20 cm), single displays predominated, volleys had fewer displays, displays were more evenly divided among the three types, and 93% of the displays had no dewlap extension. / Master of Science

Three uncertainty analysis methods, namely : (1) Monte Carlo (MC) simulation, (2) First-Order Second Moment (FOSM) method, and (3) Modified Point Estimate (MPE) method, were compared in terms of computational efficiency and accuracy for evaluation of contaminant concentration at a down-gradient receptor. Benzene and chloride, two contaminants most commonly found in petroleum exploration and production waste, were analyzed for two waste disposal scenarios, i.e. (1) closed waste pit, and (2) landspreading. Using MC method as the basis for comparison, results of the analysis suggested the use of FOSM method as the most attractive alternative to the more tedious MC method. Based on 2000 MC simulations for analysis, the FOSM method required 1.053% of the computational effort required for the MC analysis. Considering a regulatory guideline of 85% probability level of exceedance, results of the analysis indicated that the MPE method consistently underestimated the benzene concentration and overestimated the chloride concentration at a receptor, whereas the FOSM analyses indicate good agreement with MC method. However, in the event where a more precise and complete analysis is mandatory, the MC method remains the most appropriate methodology available. / Master of Science