Poly(arylene ether)s (PAEs) were synthesized via the silyl ether displacement route. Both AA, BB, and AB silylated monomers were prepared by partial or complete hydrolysis of the dihalide using potassium hydroxide in aqueous dimethyl sulfoxide followed by silylation with hexamethyl disilazane. Both linear and star-branched structures of PAEs were synthesized and this polymerization route allowed both random and block copolymers to be prepared. Triaryl phosphine oxide containing homo-& co-PAEs exhibited very high char yields, which suggested that these polymers were potentially flame-resistant materials. The AB type halogenophenols were also polymerized in the presence of diphenylsulfone as a diluent and potassium carbonate as a base at elevated temperatures. Poly(ε-caprolactam) (Nylon 6) copolymers were prepared by the incorporation of controlled molecular weight poly(arylene ether sulfone) (PES) oligomer segments into the polymer backbone which were functionalized with carboxyl end groups. A hydrolytic melt polymerization process was used to copolymerize the oligomers with ε-caprolactam. Two series of the copolymers, with varying weight ratios and PES segment lengths, were investigated. Extensive characterization experiments including thermal analysis, mechanical property measurement, wide angle x-ray diffraction and dynamic mechanical analysis were performed to illustrate that the copolymers displayed a good balance of properties. Hydrolytically stable triaryl phosphine oxide containing dicarboxylic acid monomers were synthesized and were chemically incorporated into the poly(hexamethylene adipamide) backbone to produce improved flame-resistant copolymers. The content of triaryl phosphine oxide comonomer in the melt synthesized copolymers was controlled from 0-30 mole%. The copolymers were melt crystallizable only at 10 and 20 mole% incorporation of the phosphine oxide comonomer. Cone calorimetric tests were employed to investigate the fundamental flame retardancy behavior of the copolymers. The tests were conducted in a constant heat environment (40 kW/m²). Significantly depressed heat release rates were observed for the copolymers containing phosphine oxide moiety. The results of the cone calorimetric tests and TGA data suggested that the triaryl phosphine oxide containing nylon 6,6 copolymers had improved flame resistance properties. The triaryl phosphine oxide dicarboxylic methyl ester was also introduced into poly(ethylene terephthalate) via melt transesterification to produce copolymers which had increased char yields as the P(O) content increased. However, crystallinity was totally disrupted at 20 mole percent P(O) incorporation in compression molded specimen. Novel star-branched liquid crystalline polyarylates (LCP) were made via melt acidolysis which were subsequently transformed to liquid crystalline foams by supersaturation of carbon dioxide followed by thermal blowing. It was found that the AB type monomers were essential to generate star shaped LCPs without crosslinking. The branching agents were necessary to control the molecular weights, disrupt crystallinity and to allow for higher gas uptake by the polymer matrix. / Ph. D.

Several aspects influencing the adoption of timber bridges were investigated. Initially, perceptions of timber as a bridge material were rated by highway officials in twenty-eight states. Timber was rated lowest in overall performance by each group (State Department of Transportation engineers, private consultants, and local highway officials) throughout the United States. The highest rated bridge material was prestressed concrete, followed by reinforced concrete, steel and timber. The most important factors in the bridge material decision included: Lifespan of material, past performance of material, maintenance requirements of material, resistance to natural deterioration, initial cost, and lifecycle cost. Timber was compared to other bridge materials on eight preselected attributes. Timber rated the lowest on the attributes of low maintenance, ease of design, long life, and high strength. Highway officials in four states (Mississippi, Virginia, Washington, and Wisconsin) were personally interviewed. The Analytic Hierarchy Process (AHP) was used to characterize their decision of a bridge material. The most important bridge criteria were similar in each state, however, their effect on the overall decision differed by state. Prestressed and reinforced concrete were the materials of choice in all states. The results of this study indicate that, based on the six criteria measured, timber will seldom be the material of choice for highway bridges. Timber bridge manufacturers were surveyed to understand current marketing and management techniques in the promotion of timber bridges. Marketing efforts were most prevalent in the Midwest. Timber bridge sales represented, on average, less than 7% of total sales from responding companies. Wood treating and gluelaminating firms represented over 75% of the timber bridge firms. One-half of the responding timber bridge companies felt that timber bridge sales would increase an average of 15% over the next five years. Barriers and incentives to timber bridge adoption were investigated. The greatest incentives include: year around construction, resistance to deicing chemicals, quick construction, and aesthetic qualities. Major barriers appear to be: short lifespan, maintenance requirements, decay, perceptions of strength, and that "timber doesn't perform well under high weight and traffic volumes". The realistic size of the bridge market was estimated not to exceed 600 to 700 designed bridges a year. This would require the use of 10 to 12 million board feet of lumber. / Ph. D.

This dissertation describes investigations of several methodologies appropriate for the synthesis of aromatic poly(amide-imides). An evaluation of the relative merits and drawbacks of each method has also been made based on molecular, thermal and solid state characterization of the polymers. The synthesis of both high molecular weight as well as controlled molecular weight systems has been attempted. A detailed study of the route employing an acid chloride-anhydride has been conducted, which has particularly emphasized the use of quantitative non-aqueous titrimetry and proton NMR. Residual acid was found to limit molecular weight. Hydrolytic side reactions promoted by the acid have been proposed and were subsequently confirmed. Employment of an acid scavenger such as triethyl amine as well as the effect of alternative work-up procedures on the residual acid content in the polymer has also been determined. The Yamazaki catalytic amidation reaction was found to be the most efficient among the various synthetic routes explored in this dissertation and it was used to generate a wide range of moderate to very high molecular weight polymers. Characterization of the soluble, amorphous polymers included solution viscometry in conjunction with gel permeation chromatography, vapor pressure osmometry and low angle laser light scattering. The various methods showed good correlation to one another and represent the first extensive solution characterization of soluble poly(amide-imides). The catalytic imidization of σ- ester acids was found to be a novel and rapid route with a lot of promise. Solid state transitions were investigated using a combination of a variety of techniques including DSC, Wide angle X-ray scattering, dynamic mechanical thermal analysis and dynamic melt rheometry. Many of the para-linkage containing homopolymers showed the tendency to develop crystallinity upon thermal treatment even though the initial "worked-up" polymers were amorphous. This aspect has hitherto not been reported and promises to be extremely valuable in allowing initially amorphous polymers to be easily processed to the desired shapes followed by a thermal treatment to develop crystallinity that would enhance solvent resistance and thermooxidative stability. Some novel poly(amide-imides) were also synthesized that showed improvements in existing properties such as increased flame-retardancy and elevated glass transition temperatures. / Ph. D.

The primary objective of this study was to investigate the roles of plant proteinase inhibitors in plant-nematode (Meloidogyne spp.) interactions. Transgenic tomato and tobacco plants were employed to examine the effects of proteinase inhibitor I or II transgene on nematode disease development. In the first part of this study, tomato and tobacco root cultures and seedlings aseptically grown in agar medium were developed to test the roles of proteinase inhibitor transgenes in enhancing plant resistance against nematodes. Root galling in cultured root and seedlings expressing inhibitor I or II gene was reduced as compared with controls. Nematode development was also retarded in proteinase inhibitor-expressing root cultures. In the second part of this study, the effects of high expression of proteinase inhibitor I or II transgene on nematode disease development were examined in whole plants grown under greenhouse conditions. It was found that both root galling, nematode egg and egg mass production were inhibited in transgenic tomato plants during the early infection stage. However, this inhibition ceased during the late infection stage. The suitability of cauliflower mosaic virus (CaMV) 35S promoter used for transgene constructs was evaluated in this study. It was found that the expression of proteinase inhibitors, driven by the CaMV 35S promoter, decreased in root tissues of transgenic plants during late nematode infection stage. The developmental expression pattern of proteinase inhibitors in root tissues was clearly correlated with nematode disease development. In addition, the GUS gene, driven by CaMV 35S promoter, was not expressed in gall tissues containing feeding nematodes during the late infection Stage. The results of this study suggested that CaMV 35S promoter might not be suitable for engineering nematode resistant crop plants. Additional experiments were performed to identify the proteolytic activity present in root-knot nematodes at different developmental stages. Both trypsin and chymotrypsin activities were detected in second-stage juvenile extracts. Only trypsin activity was found in female extracts. Both tomato proteinase inhibitor I and II were induced in root tissues in response to nematode infection. The preliminary results of this study further confirmed the involvement of proteinases and proteinase inhibitors in plant-nematode interactions. / Ph. D.

Poly(arylene ether)s containing phosphorus, sulfur, and heterocyclic pendant moieties were synthesized and their properties investigated. The preparation of monomers containing phosphorus as well as monomers derived from phenolphthalein were synthesized in high purity. These monomers were then successfully polymerized by a nucleophilic displacement reaction to prepare poly(arylene ether)s of both high and controlled molecular weight. The novel poly(arylene ether)s based on phenolphthalein had glass transition temperatures ranging from 265 to 312 °C. Furthermore, the modulus of these macromolecules was significantly higher than that of typical poly(arylene ether)s (e.g. bisphenol A based systems), probably as a result of enhanced intermolecular forces. Phenolphthalein in poly(arylene ether)s has been shown not only to improve the thermal and mechanical properties, but also it provides a pendant functional group for chemical modification of the polymer. As a result, a base polymer can be customized to a variety of new materials using derivatization techniques. The possibility of metal complexing in phenolphthalein poly(arylene ether)s was also investigated. A variety of reactive and non-reactive end-capped poly(arylene ether)s of controlled molecular weight were synthesized for use in reactive toughening modified epoxy and cyanate ester networks and these results are briefly summarized. Model studies using HPLC were also conducted to determine reaction kinetics in nucleophilic poly(arylene ether) formation. The results demonstrate that potassium carbonate mediated step polymerizations likely proceed with etherification of one of the phenolic groups, prior to difunctional coupling, which can achieve high molecular weight. The formation of cyclic oligomers in the step-growth polymerization of poly(arylene ether)s was also studied. / Ph. D.

Knowledge of water distribution in sludges is important in developing a better understanding of the mechanisms by which various fractions of water are bound to the sludge matrix as well as the extent to which sludges may be dewatered in an economic manner. Various models have been proposed in the literature to describe the types or fractions of water present in sludges, both before and after dewatering. Likewise, there exist a variety of measurement techniques to quantify the fractions of water believed to be present in sludges. The major objective of the research reported herein was an attempt to develop a more rational basis for defining the various fractions of water present in sludges, as well as to apply and develop feasible analytical techniques to characterize moisture distribution in sludges and determine if there was any correlation between these techniques. Secondary objectives included investigation of polymer addition, mechanical dewatering, and the effect of freeze-thaw cycles to different water fractions in sludge samples, and measuring or estimating various densities (bulk, floc, dry) and specific surface areas of sludge particles in an attempt to predict the dewatering performance of various sludge samples. The matrix of sludges included various water treatment plant/inorganic chemical sludges and biosolids. The sludge moisture characterization techniques used or developed in this study were the thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dilatometric methods. The TGA method developed used the drying curve rate technique whereby changes in the drying (water removal) rates would provide information on moisture distribution in sludges. The DSC and dilatometric methods used the property of the free water fraction to freeze by -20° C, as compared to the bound water fraction that is thought not to freeze until well below -20°C. It was found that there were uncertainties in the determination of different sub-fractions of sludge water. In an effort to better rationalize these various subfractions, it has been proposed in this study that water in sludges be considered to be in two major fractions: bound and unbound. For the TGA, the demarcation point between these two fractions was indicated by the onset of the first critical/inflection point on the drying rate curve. The DSC and dilatometric methods determined the amount of bound water by first measuring the amount of unbound water that froze by -20°C, and subtracting this value from the total water present in the dry solids analysis. While the DSC measured the calorimetric (enthalpic) changes, the dilatometer measured the expansion of the unbound water. The three DSC instruments evaluated in this study were not able to measure the rapid exothermic change of the freezing of unbound water, but was able to measure the amount of unbound water that melted. Freezing point depression (supercooling) phenomena was also observed for various samples using this technique. Due to these effects, the sludge moisture characterization method developed for the DSC measured the amount of unbound water from the endothermic changes upon melting. The three different analytical techniques used to determine moisture in sludges were found to provide different quantities of the bound water fraction. Other sludge characteristics evaluated included the bulk, floc, and dry density values, as well as the specific surface area of dry sludge particles. Correlations were attempted to determine if there were any meaningful relationships in the results obtained. / Ph. D.

This dissertation is concerned with the global optimization of polynomial programming problems, and a detailed treatment of its particular special case, the indefinite quadratic programming problem. Polynomial programming problems are generally nonconvex, involving the optimization of a polynomial objective function over a compact feasible region defined in terms of polynomial constraints. These problems arise in a variety of applications in the context of engineering design and chemical process design situations. Despite the wide applicability of these classes of problems, there is a significant gap between the theory and practice in this field, principally due to the challenge faced in solving these rather difficult problems. The purpose of this dissertation is to introduce new solution strategies that assist in closing this gap. For solving polynomial programming problems, we present a branch and bound algorithm that uses a Reformulation Linearization Technique (RLT) to generate tight linear programming relaxations. This bounding scheme involves an automatic reformulation of the problem via the addition of certain nonlinear implied constraints that are generated by using the products of the simple bounding restrictions and, optionally, products involving the structural constraints. Subsequently, in a linearization phase, each distinct nonlinear term in the resulting problem is replaced by a new variable to obtain a linear program. The underlying purpose of this procedure is to closely approximate the convex envelope of the objective function over the convex hull of the feasible region. Various implementation issues regarding the derivation of such a bounding problem using the RLT, and the dominance of such bounds over existing alternative schemes, are investigated, both the- theoretically and computationally. The principal thrust of the proposed method is to construct a tight linear programming relaxation of the problem via an appropriate RLT procedure, and to use this in concert with a suitable partitioning strategy, in order to derive a practically effective algorithm that is theoretically guaranteed to be globally convergent. To address various implementation issues, empirical experiments are conducted using several test problems from the literature, many motivated by the aforementioned practical applications. Our results on solving several such practical engineering design problems demonstrate the viability of the proposed approach. This approach is also specialized and further enhanced for the particular class of indefinite (and concave) quadratic programming problems. These problems are important in their own right, and arise in many applications such as in modelling economies of scale in a cost structure, in location-allocation problems, several production planning and risk management problems, and in various other mathematical models such as the maximum clique problem and the jointly constrained bilinear programming problem. The proposed algorithm is more than just a specialization of the polynomial programming approach; it involves new, nontrivial extensions that exploit the particular special structure of the problem, along with many additional supporting features that improve the computational efficiency of the procedure. Certain types of nonlinearities are also retained and handled implicitly within the bounding problem to obtain sharper bounds. Computational results are presented on a set of test problems from the literature to demonstrate the efficiency of the approach. (One of these test problems had not previously been solved to optimality.) It is shown that for many problems, including randomly generated problems having up to 50 variables, the initial relaxation itself produces an optimal or a near optimal solution. This is significant in that the proposed methodology affords an approach whereby such hard nonconvex problems can be practically solved via a single or a few higher dimensional linear programming problems. / Ph. D.

The efficiency of a flashing flow converging-diverging nozzle was measured. The primary motivation for measurement of nozzle efficiency in this work was to improve the performance of an ejector as a refrigerant expander; previous experimentation has suggested that motive nozzle efficiency is poor. Measurement of the efficiency was performed using a technique which does not require knowledge of the non-equilibrium nozzle outlet state. This technique is based on the measurement of nozzle thrust and mass flow rate to determine the actual kinetic energy at the nozzle exit. A vapor compression refrigeration cycle using refrigerant R-12 was employed to test the nozzle. Use of a bubble seeding device upstream of the nozzle to provide nucleation sites in the flow was expected to decrease the non-equilibrium, therefore producing an increase in nozzle efficiency. Experiments were performed at various condenser pressures and mass flow rates. In addition to the efficiency measurement, a parameter to quantify the metastability in the nozzle flow was defined and empirical correlations were developed for both. The experimentation illustrated that the efficiency did indeed increase when flow conditions were closer to equilibrium. Efficiency and metastability parameter results indicate an unexplained dependence on the condenser subcooling. Recommendations were therefore made to investigate this unexpected phenomenon. / M.S.

Many bodybuilders attempt to lose large amounts of weight in short periods of time through the use of low energy diets. Research suggests that consumption of a low energy, low carbohydrate diet may negatively affect mood states. Further research suggests that carbohydrate consumption can positively affect mood states. This study evaluated two main ideas: (1) does the consumption of a carbohydrate supplement affect mood states during weight training bouts and (2) does carbohydrate supplementation affect perception of effort of a weight training bout. Male weightlifters (N=17) consumed a low energy diet for four days (21 kcal/kg body weight). On the fifth day, the weightlifters consumed either a carbohydrate beverage ( "Sports Shot" at 1.15 gm CHO/kg bw) or a placebo beverage ( "Challenge" at 1.06 gm protein/kg bw) before testing was started. The subjects filled out a Profile of Mood states (POMS) questionnaire fifteen minutes prior to and immediately after a bench press exercise test. The flat bench press exercise test consisted of lifting 7 sets of decreasing repetitions at 60% of their maximum lift with the final set continuing until volitional fatigue. Ratings of Perceived Exertion (RPE) were recorded between each set. Data were analyzed by three-way ANOVA. The carbohydrate group had a significantly (p<0.05) lower total POMS score compared with the placebo and control groups (30±5.84 vs. 46.6±5.84 and 42.3±5.46). There were no differences in RPE between groups. These results suggest that carbohydrate ingestion 15 minutes prior to lifting weights decreases the total mood disturbance that may be experienced while lifting on a low-calorie diet. / M.S.

Research in cellulose esters in recent years has concentrated on creating a variety of novel esters with a wide range of thermal and mechanical properties. These cellulose derivatives can be used for membranes, coatings, polymer blends, and other products. Novel cellulose solvent systems (DMAc/LiCl) introduced within the last twenty years have allowed the use of several esterification techniques that could not be used effectively in the past. The combination of the new cellulose solvent systems and esterification chemistry has enabled a large variety of novel cellulose esters to be produced. Four groups of novel cellulose esters were produced in this study, cellulose trifluoroethoxy acetate (CT), cellulose acetate trifluoroethoxy acetate (CATA), cellulose esters of long chain linear aliphatic acids, and cellulose acetate laurate (CAL). The derivatives were synthesized in a homogeneous reaction medium of DMAc/LiCl. Several esterification chemistries were used including one based on reactions with TsCl (para-tolulene sulphonyl chloride). A wide range of degree of substitutions (DS) were produced without degradation to the starting polymer using a range of stoichiometric ratios. The fully substituted mixed cellulose esters were synthesized by consecutive reactions (work-up between reactions) and by "single pot" reactions. "Single" cellulose esters, with free hydroxyls, were produced by single pot reactions. Structure property relationships were examined by several thermal and mechanical analyses. Mechanical response was studied with dynamic mechanical thermal analysis (DMTA) and thermal mechanical analysis (TMA). Thermal response was recorded by differential scanning calorimetry (DSC) and visual analysis. The CT derivatives revealed a linear relationship between T_g and DS between a DS range of 0.6 and 3.0, but no T_m was apparent. All the products with DS > 0.6 flowed without discoloration, therefore the materials were assumed to be mainly amorphous. The CATA derivatives revealed sharp T_gs and T_ms. Surprisingly, the T_gs did not change between the CT and CATA derivatives, and the CATA's T_ms decreased linearly with increasing DS of fluoro-ester. Substituent and main chain T_gs were observed for both CT and CATA derivatives, but the substituent T_g remaining constant throughout the DS range of the flouro-esters. Surprising solubilities were also observed for both CT and CATA derivatives. The long linear aliphatic cellulose esters (with C₁₂ to C₂₀ alkyl substituents) revealed a wide range of thermal and mechanical responses. Side chain and main chain T_gs and T_ms were observed for C₁₂ and C₁₄ derivatives. Only one broad T_m with no T_g was observed for C₁₈ and C₂₀ derivatives by DSC analysis. After annealing, multiple crystalline responses were seen for all the highly substituted C₁₂ to C₂₀ cellulose esters. CAL derivatives revealed sharp T_ms with no T_g. The crystallization rate proved to be much faster for the CAL derivatives than any other derivative in this study. / M.S.