In this dissertation, the response of a slender, elastic, cantilevered beam to a simple harmonic excitation is investigated. The effects of nonlinear curvature, nonlinear inertia, viscous damping and static load are included. The nonlinear equations governing the motion of the beam are derived by the Lagrangian approach. The deflections are expressed as expansions in terms of the linear free-vibration modes. Galerkin’s method is used to eliminate the spatial functions from the governing equations. Three modes are used in this procedure. Approximate solutions of the temporal equations are determined by the method of multiple scales. Four first-order ordinary differential equations govern the amplitudes and phases, and predict a whirling motion under certain situations. The solutions of the modulation equations can be fixed points, limit cycles or chaotic motions. Previous studies considered whirling produced by a primary resonance. In this dissertation, secondary resonances are considered in addition to primary resonance. Previous derivations of equations of motion contain only the linear and cubic terms without consideration of the static displacement produced by the weight of the beam. As a result of this static deflection, there are quadratic terms in the governing equations which introduce the possibility of a superharmonic resonance of order two and a subharmonic resonance of order two. It is shown that out-of-plane motion is possible in every resonance when the principal moments of inertia of the beam cross-section are approximately equal. The longer the beam is, the more prominent the whirling motion becomes. If the excitation frequency is increased or decreased through a resonance, for most cases, the non-stationary response from the method of multiple scales shows good agreement with that from the original differential equations. / Ph. D.

Let <b>X</b> be a compact Hausdorff space and <b>A</b> a uniform algebra on <b>X</b>. Let if be an isometric unital representation that maps <b>A</b> into bounded linear operators on a Hilbert space. This research investigated that there is a one-to-one correspondence between the collection of maximal sets of antisymmetry for <b>A</b> and that of maximal projections of antisymmetry for π (<b>A</b>) under the extension of π if π satisfies a certain regularity property. / Ph. D.

The oxidative addition of the N-H bond of both heterocyclic and acyclic amines and the O-H bond of phenols, water and carboxylic acids to iridium(I) trimethylphosphines complexes was studied and the reactivity of the resulting hydrido amido-, aryloxo- and carboxylato iridium(III) complexes was investigated. Oxidative addition of the N-H bond of pyrrole, indole, 3-methylindole, 7-azaindole, carbazole and aniline to [Ir(COD)(PMe₃)₃]CI (<b>1a</b>) (COD = 1,5-cyclooctadiene) produces merIr( NR₂)H(PMe₃)₃CI (<b>2a-f</b>) complexes. That these amines were bound to iridium through an Ir-N bond was established by ¹H, ³¹P and ¹³C NMR spectroscopy, IR spectroscopy, C-H analyses and single crystal x-ray diffraction. Similarly, oxidative addition of the O-H bond of phenol, p-cresol, 3,5-dimethylphenol, and water to [Ir(COD)(PMe₃)₃]CI (la) produces mer-Ir(OR)H(PMe₃)₃C1 (<b>5a-c and 6</b>) which were characterized by ¹H, ³¹P and ¹³C NMR spectroscopy, C H analyses and single crystal x-ray diffraction. A preliminary study of the reactivity of both the amido and aryloxo complexes suggests that because of the increased electron affinity of the heteroatoms involved (N or 0), there is high electron density at the heteroatoms in these complexes and therefore the M-N or M-O bond can heterolyze more easily than M-C bonds. This increased tendency of the M-N or M-O bond to heterolyze leads to decomposition reactions when attempts are made to open up a coordination site at the metal center by removing the chloride ligand. / Ph. D.

This work presents data concerning the optical nature of the insulated gate field effect transistor (IGFET), how its optical sensitivity relates to its electrical operation, and explores its usefulness as a microluminometer for a chemisensor and biosensor. Although the experiments performed for this dissertation show that the IGFET's light sensitivity does not involve the standard operation of the FET, i.e., the modulation of the source to drain current, they also show that the IGFET's light sensitivity is not a simple photodiode response of the source/base or drain/base junction. This work raises many interesting questions to be answered by future studies concerning the light sensitivity of the IGFET and its possible uses. In this work an instrument was built to probe the IGFET with photons, the IGFET's wavelength response is presented, the detection of recaequorin in a static system is shown to have a limit of detection of 6*10⁻²⁰ moles of recaequorin, and the IGFET is demonstrated as a microluminometer in a FIA system for detecting hypochlorite. The hypochlorite limit of detection is 39 * 10⁻¹² moles.. The author proposes new uses for the IGFET employing its traditional ion sensing role as well as its photosensitivity. Construction of a three dimensional biosensor is suggested. / Ph. D.

Five experiments were conducted to investigate the effects of early feed restriction on body weights, feed conversion, organ weights, fat deposition, carcass and muscle composition, plasma lipids, lipogenesis, lipolysis, and muscle tissue DNA and RNA in broiler chickens. In Experiments 1 and 2, broiler chicks were reared in litter pens for 49 days, while Experiments 3,4, and 5 were conducted in battery cages for 28 days. Feed restriction in all experiments was induced by providing male broiler chicks with 40 kcal/bird/day for 7 (Experiments 1 and 2) or 6 (Experiments 3, 4, and 5) days, starting at 4 days of age. Feed restriction (40 kcal/bird/day) for broiler females in Experiment 1 was imposed from 4 to 9 days of age. Ad libitum feeding was resumed after the restriction periods and continued to the conclusion of each experiment. Broilers fed ad libitum for the entire experimental period were used as controls in each study. Broilers under early feed restriction had significantly (P s .05) lower mean body weights than ad libitum fed controls, for all ages measured. However, feed to gain ratios for restricted birds were Significantly lower at 28 (Experiments 1 through 4) and 49 (Experiments 1 and 2) days of age than for birds fed ad libitum. Total pen body weights for restricted and ad libitum fed groups were similar at 49 days of age in Experiments 1 and 2 which, reflected a significant reduction in the rate of mortality observed in the early restricted groups. Significantly higher levels of lipogenic activity, plasma triglycerides and lipoproteins (VLDL + LDL), and significantly larger abdominal fat pads were observed in restricted broilers than in ad libitum fed controls at 28 days of age (Experiment 4). No significant differences were found in organ weights, carcass composition, lipolysis, and muscle tissue DNA/RNA levels, and muscle composition between early restricted and unrestricted broilers. Results from these studies indicate that restricted broilers were not able to attain body weights comparable to ad libitum fed birds at 49 days of age. In contrast, early feed restriction resulted in consistently better feed efficiency in restricted birds when compared to controls. Furthermore, it appears that early feed restriction altered lipid metabolism early in life; however, organ weights, fat deposition, muscle composition, and carcass composition were only minimally affected by this procedure. / Ph. D.

Wing structures often contain nonlinearities which affect their aeroelastic behavior and performance characteristics. Aerodynamic flows at transonic Mach numbers generate nonlinear aerodynamic forces on the wing affecting the aeroelastic response of the wing. Analysis techniques accounting for these structural and aerodynamic nonlinearities, and an understanding of their potential influence on the flutter mechanism of two-dimensional and three-dimensional wing-structures model are the main objective of this study. Two different categories of structural nonlinearities, i.e. (i) distributed nonlinearity and (ii) concentrated nonlinearity , are considered. The concentrated nonlinearities are mathematically modeled using Asymptotic Expansion method which based on on the Krylov-Bogoliubov-Mitropolski technique. The effective stiffness coefficient of a nonlinear element is defined as the ratio of the amplitude of the Fourier series expansion of the load and the amplitude of the displacement of that element. The effects of distributed nonlinearities on the aeroelastic characteristic of three-dimensional wing model are also investigated. The influences of this type of nonlinearity is treated in a quasi-nonlinear approach, which allows the variation of the the natural frequencies and damping factor of the structure model with respect to the amplitude of the motion. The transonic aerodynamic pressure distributions have been obtained by solving the unsteady Transonic Small Disturbance ( TSD ) flow equation using finite-difference techniques. An Alternating Direction Implicit ( ADI ) algorithm was used for two-dimensional flow model, and an Approximate Factorization ( AF ) algorithm was used for three-dimensional flow model. The finite-state generalized aerodynamic forces used in the aeroelastic analysis have been calculated by employing the Method of Harmonic Oscillation and the Pulse Transfer Function analysis. The solution of the aeroelastic equation in frequency domain is obtained by representing the equation in a finite-state form through the modal approach using Lagrange’s equation. The flutter boundary is obtained by solving this equation using the classical U-g method and root locus analysis. Flutter analysis of a two degree-of-freedom , two-dimensional typical wing sections with nonlinear torsional springs are studied. The aeroelastic responses of the system are obtained by integrating the nonlinear structural terms and aerodynamic terms simultaneously using Newmark-β and Wilson-θ methods. Flutter results obtained from both time integration and eigenvalue solutions are compared. These two results, in general, are in agreement. Flutter behavior of a simple three-dimensional swept wing model is also investigated. Comparison of the flutter boundary obtained by using the eigenvalue solution with flutter data from wind-tunnel experiments are made. / Ph. D.

The overall objective of this work was to enhance the mechanical properties of thermoplastics by blending with liquid crystalline polymers (LCPs). Injection molding and sheet extrusion studies of blends of poly(ethylene terephthalate) (PET) with several LCPs were conducted with an emphasis on blends containing 50 wt % or less of the LCP. It was seen that significant enhancements (50-350%) in the tensile and flex moduli of PET were achieved by blending with 0-50 wt % LCPs via injection molding. The level of property enhancements was lower in the case of-sheet extrusion due largely to processing limitations which made it difficult to obtain high draw ratios. Since thermotropic LCPs typically have high melting temperatures it is difficult to blend several thermoplastics such as polypropylene (PP) with these LCPs in the same extruder or molding unit. Thus a blending method (hereon referred to as the dual-extruder mixing method) was developed to overcome this limitation. In this method, the matrix and LCP polymers were plasticated in two separate extruders, subsequently mixed downstream in a static mixer (Kenics) and the melt blend than passed through an appropriate capillary or sheet die to generate strands or sheets, respectively. Using this method, blends of PET and PP with several LCPs were extruded into strands and sheets. In some cases, for example PP and Vectra A900 (LCP), the difference in their normal processing temperatures was in excess of 100°C. Strands of PET/Vectra A900 70/30 composition ratio were observed to have higher moduli than a blend of the same composition extruded using a single extruder at all the draw ratios tested. This was determined to be due to the different LCP fibrillar morphology in the two cases. In the case of the dual-extruder mixing method, the LcP fibrils were continuous, running the length of the extrudate, and further devoid of any skin-core structure. In contrast, the single-screw extruder blend had a distinct skin-core fibril-droplet type of structure and the LCP fibrils were not continuous. On the basis of other independent experiments, it was confirmed that the LCP fibrils in the dual-extruder mixing method were generated in the static mixer itself whereas the LCP fibrils in the case of single-screw extrusion were generated in the converging section of the die and/or by drawing at the die exit. This difference in the mode of LCP fibril generation in the two cases was attributed to the distributive mixing mechanism of the static mixer compared to the dispersive mixing in the extruder. Strands of PP/LCP and PET/LCP had significantly enhanced tensile moduli compared to the corresponding matrix tensile modulus. Enhancements of 10-20 times that of the pure matrix were achieved when blends containing about 20-30 wt % of the LCP were extruded from the dual-extruder mixing method. The tensile moduli of sheets of PET/LCP and PP/LCP blends were not much higher than that of the corresponding matrix polymer and this was attributed to the low molecular orientation achieved in the sheets due to low draw ratios. The tensile strengths of the majority of the blends were not enhanced to any appreciable degree and poor wetting and adhesion between the thermoplastic-LCP polymers was believed to be the cause. Comparison of some of the mechanical properties (tensile modulus, tensile strength, flexural modulus) of the thermoplastic/LCP blends generated in this study with data from the literature on thermoplastic/inorganic filler composites showed that when compared on the basis of equal wt % of the reinforcement in the blend, the LCP composites can yield mechanical properties which are in the same range as those obtained using inorganic fillers. / Ph. D.

Data from two groups of lambs were analyzed. In group one, seasonal patterns of testis growth through 16 mo of age were assessed on 40 spring-born ram lambs (eight Barbados Blackbelly, 10 Suffolk and 22 1/2-Dorset, 1/4-Finnish Landrace, 1/4-Rambouillet). Scrotal circumference (sc) and body weight (wt) were measured at mean ages of 30, 62, 96, 124, 153, 180, 212, 243, 290, 333, 364, 398, 427, 454, 488 and 517 d. A multivariate repeated measures analysis indicated that there were breed differences in ram sc and wt measurements at each age. When logistic growth curves were fit to ram sc data, breed differences were associated with parameters of the logistic curve that defined mature testis size and the period of rapid testis growth. For group two, data were collected on 1,044 lambs from 727 spring lambings over 5 years; 67 sires and 525 dams were represented. Sc and wt were measured in rams at 5 times (mean ages of 44, 63, 97, 129 and 156 d); ewes were weighed at these times and at three additional times (187, 230 and 271 d). All ewe lambs were kept for fall breeding. Fertility, prolificacy and postweaning spring mating behavior of ewes that had lambed were measured. After ewes lambed, they were exposed to vasectomized rams and checked for postweaning spring mating behavior. Restricted maximum likelihood (REML) was used to estimate variance components for additive genetic, ewe, and litter effects in group two Jambs. Heritability estimates for wt at birth to 150 d ranged from .14 to .42. Heritabilities for sc and sc scaled to the 1/3 power of body weight (rsc) ranged from .09 to .57 and from .13 to .55, respectively, and were largest at approximately 90 d. Logistic sc growth curves were fitted to data from individual ram lambs. Heritabilities of the estimated logistic parameters mature sc (A), sc maturing rate (k), age at inflection of the sc growth curve (t₁) and initial 14-d sc (SC14), were estimated at .09±.15, .17±.18, .37±.29 and .40±.14, respectively. Heritability estimates for fertility and spring mating behavior (spbrd) were .04±.13 and .41±.19, respectively. The heritability estimate for prolificacy was zero. Longitudinal additive genetic covariances among wt, sc and rsc at the second, third and fourth measurements were estimated from approximate multivariate REML analysis treating variances as known. Estimated genetic correlations among wts were largest, and ranged from. 77 to .93. Estimated genetic correlations for rsc traits were between .48 and .90. Estimated genetic correlations for sc ranged only from .10 to .67. Pairwise genetic correlations among sc or rsc with fertility or spbrd were estimated to be moderate and positive (.20 and .34, respectively); t₁ had correlations of -.32 and -.48 with fertility and spbrd, respectively. / Ph. D.

The mechanism of catalytic hydroboration was studied through the use of iridium and rhodium model complexes. Oxidative addition of the B-H bond in (1,2-phenylenedioxy) borane (catecholborane) to (Me₃P)₃Ir(Cl)(H) (BO₂C₆H₄ (<B>II</B>) produces <i>mer</i>-(Me₃P}₃Ir(Cl)(H)(B0₂C₆H₄) (<B>II</B>), which was characterized by ¹H NMR spectroscopy and single crystal X-ray diffraction. Compound <B>II</B> reacted with alkynes to form vinyliridium complexes and will catalyze the hydroboration of alkynes with (1,2- phenylenedioxy)borane. The reaction of <B>II</B> with acetylenes was inhibited by the presence of free Lewis bases indicating that the reaction proceeds by a dissociative mechanism. Exchange of the chloride ligand in <B>II</B> occurred with other Lewis bases, indicating that chloride dissociation was responsible for opening up the vacant coordination site on the complex and thus providing for acetylene coordination. When the chloride ligand on <B>II</B> was replaced with other Lewis bases, the reactivity towards trimethylsiliylacetylene was qualitatively determined to be inversely proportional to the strength of the new ligand. The above experiments indicated that the mechanism of catalytic hydroboration of acetylenes with catecholborane involves: oxidative addition of the B-H bond to the iridium center, followed by chloride dissociation and acetylene coordination, migratory-insertion into the Ir-H bond to form the metallo-vinyl complex, and finally reductive elimination to produce trans-alkylvinylborole esters. The stable metallo-vinyl complex, <b>IX</b>, produced in the reaction of <b>II</b> with dimethyl acetylene dicarboxylate produced twO isomers in solution, one of which showed fluxional behavior. Single crystal X-ray diffraction elucidated a single solid state structure, but the structures of the isomers in solution and the fluxional properties observed have not yet been explained. The rhodium complex was synthesized by oxidative addition of the B-H bond in (1,2- phenylenedioxy) borane to (Me₃P)₃RhCl producing <i>mer</i>-(Me₃Rh(CI)(H)(BO₂C₆H-₄) (<b>XXIV</b>), which was characterized by ¹H NMR spectroscopy. This complex reacted with acetylenes, but more slowly than the iridium complex, <b>II</b>. The resulting vinyl products were also different than those produced in the iridium case. Phosphine dissociation in <b>XXIV</b> was observed, indicating the possibility of a different mechanism than proposed for the iridium complex. / Ph. D.

The activity of the enzyme 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR, EC 1.1.1.34) is highly expressed in 4-day-old etiolated seedlings of normal ('DeKalb XL72AA'), dwarf (<u>d₅</u>), and albino (<u>lw₃</u>) maize (<u>Zea mays</u> L.). HMGR activity of maize seedlings appeared to be exclusively associated with the microsomal rather than the plastidic fraction of maize cells. Maize tissues with high meristematic activity such as germinating seeds, leaf bases, root tips, and the site of origin of lateral roots contained high levels of HMGR activity. The activity of HMGR extracted from leaf tips of normal, dwarf, and albino maize seedlings was regulated by light. HMGR activity from leaf tips of 4-day-old maize seedlings was inhibited significantly following exposure to strong light (600 μol/m²/s) for more than 10 h. In contrast, HMGR activity from leaf bases and root tips of maize was not inhibited by exposure to strong light. These results suggest that HMGR may play an important role in cell division and that light may regulate HMGR activity indirectly by increasing cell differentiation. Under conditions of strong light pretreatment with the bleaching herbicides clomazone, norflurazon, fluridone and acifluorfen stimulated by 4-to 7-fold the activity of HMGR extracted from 'Dekalb XL72AA' maize seedlings. / Ph. D.