Very limited research studies have been conducted to examine bond of glass fibre reinforced polymer (GFRP) bars with high concrete strength. The current research project aims to compare between bond measured from a pull-out test and a hinged beam test for GFRP bars embedded in high strength concrete. Different parameters influencing bond such as GFRP bar diameter, embedment length and surface configuration were investigated in both test methods, while the bar position, i.e. top or bottom, was only studied in hinged beams. Seventy-two pull-out cubes, eight pull-out prisms and twenty-four hinged beams reinforced with GFRP bars were constructed and tested to failure. Twelve pull-out cubes and four hinged beams reinforced with steel bars were also tested for comparison purposes. The results showed that bond stress – slip curves obtained from various testing methods were similar, consisting of high initial stiffness, followed by nonlinear ascending and softening branches. In addition, it was found that the experimental bond strength obtained from hinged beams was higher than both bond strengths measured by the pull-out cube and pull-out prism. However, when a finite element analysis was conducted for hinged beams, it was shown that the tensile force in the reinforcing bar estimated by equilibrium conditions is overestimated as the large deformation of hinged beams at failure was not considered. Therefore, if the tensile force obtained from the finite element analysis is used to calculate the bond strength, it would be similar to that obtained from pull-out cube and prism. Moreover, it was found that the distribution of tensile and bond stresses was nonlinear along the GFRP embedment length and bond stress at the vicinity of the free end increased with increasing the load due to redistribution of bond stresses along the embedment length. Bond strengths were compared against the prediction methods provided in ACI-440.1R, CSA-S806, CSA-S6 and JSCE 1997. In general, all design codes showed conservative results for all specimens tested and ACI predictions gave a good agreement with experimental data compared to other codes. Artificial neural network models were developed to predict bond strength of GFRP bars in concrete. These models used bar diameter, embedment length, concrete compressive strength and concrete cover as input variables. The developed ANN models showed to be able to predict bond strength of GFRP bars in concrete and, therefore, were used to conduct a parametric study. / Higher Education Institute, Government of Libya

Solvent effects on the chemical exchange of a push pull Ethylenes <p> Chemical exchange rates provide a sensitive probe of solvent effects in solution. The push-pull ethylene methyl 3-dimethylamino-2-cyanocrotonate (MDACC) has three exchange processes E-Z (the same as E' -Z'), E-E', and Z-Z', and we have measured these rates in acetone-d6, chloroform-d, tetrahydrofuran-d8, toluene-d8, methanol-d4, acetonitrile-d3, and methylene chloride-d2 through 1D 1 H.NMR at different temperatures. From this we obtain ΔG+, ΔHt+, ΔS+ of activation for each solvent by employing an Eyring plot. As the solvent changes, ΔH+ is approximately constant whereas ΔS+ follows the solvent polarity. </p> <p> Since the equilibrium constant is less than one, we would expect it to increase with temperature, but it decreases. This is seen in the Van't Hoff plot where the slope is positive indicating that the process of going from the major site to the minor site is exothermic, so not only is the rate governed by entropy effects, but also the equilibrium constant between E and Z. </p> <p> The rotation between the C-N and the C=C bond occurs through a non-concerted mechanism. Two reasons why this occurred was apparent through EXSY, since the intensity of the off diagonal peak varies with different mixing time and second, the rates from C=C rotation (E-Z) and C-N rotations (E-E' and Z-Z') are different at the same temperature </p> / Thesis / Master of Science (MSc)

Denna uppsats ska studera hur befolkningsutveckling och flyttmönster påverkas av lärosäten i Sverige. Sedan 1990-talet har andelen utbildade med högre utbildning sett en ständig ökning. Lärosäten fick med högskolereformen 1993 större frihet hur utvecklingen skulle ske. Samtidigt förändrades utbildningens strukturer från att vara linjebaserad till att vara programbaserad. Detta ledde till att högre utbildning blev mer tillgängliga för individer vilket har lett till ökningen av utbildade i Sverige. Kommuner med lärosäten blir därför mer eftersökta till följd av en högre vilja av att utbilda sig vidare efter gymnasiet.  Denna studie ska därför försöka besvara hur olika kommuner blir påverkade av de lärosäten som finns runt om i landet. Målet för studien är Sveriges 290 kommuner och de lärosäten som är belägna i olika kommuner som erbjuder en högre utbildning, 3 år eller längre eftergymnasial utbildning. Genom användandet av registerdata från Statistiska centralbyrån [SCB] baserat på befolkningen i Sveriges kommuner, ska studien belysa hur olika faktorer kan påverka hur flyttmönster kan synliggöras och förklaras. Trender ska synliggöras utifrån olika utgångspunkter som hur en kommuns socioekonomiska bakgrund påverkar flyttmönster. Även hur push-pull påverkar hur kommuner kan vara attraktiva för vissa och avvisande för andra, där ålder är en faktor i hur en livsstil förändras under tid. Denna studie ska undersöka hur befolkningsutvecklingen sett ut, genom att skapa cirklar med intervallspann på 50 kilometers avstånd från samtliga svenska lärosäten. De kommuner som faller inom detta upptagningsområde kommer att benämnas vara inom ett högre lärosätets influensfält då det även innefattar påverkan utåt genom en export och skapande av kunskap. Därav blir frågan om lärosätenas lokalisering har en påverkan på befolkningsutvecklingen genom sin dragkraft av människor, samt hur stark och hur långt sträcker sig deras influensfält? Studien synliggör mönster hur individer i åldersgruppen 18-25 i större grad flyttar från kommuner utan lärosäten och samtidigt ökar inflyttningen till kommuner med lärosäten. Den största minskningen visar sig vara i kommungrupper inom pendlingsavstånd till kommunerna med lärosäten. Kommuner kring storstäderna och kommuner med högre lärosäten upplever en tillväxt av deras utbildade befolkning och samtidigt en hög nettoutflytt av den yngre åldersgruppen. Samtidigt som en minskning sker bland pendlingskommuner och landsbygdskommuner ser de även en positiv nettoinflytt av äldre åldersgrupperna 46-55 och 56-65. Efter en viss ålder synliggörs ett förändrat flyttmönster med en högre flyttfrekvens från storstäderna och större städer mot pendlingskommuner, mindre stad/tätorter och landsbygdskommuner. Lärosätena har även påverkat kommuner utan lärosäten då generellt alla kommuner ser en positiv ökning i utbildningsgraden, även om den är liten eller i mindre utbredning jämfört med större kommuner. Denna slutsats tolkas bero på att många unga flyttar för högre studier men väljer sedan att flytta därifrån efter avklarade studier vilket ökat den nationella utbildningsgraden.

Cyclic ketene-N,N-acetal chemistry was explored. 2-Methylimidazoline and 2-methyl-1,4,5,6-tetrahydropyrimidine derivatives were prepared from the condensation reactions of diamines with nitriles under Lewis acid catalysis and used as the precursors of cyclic ketene-N,N-acetals including the N-methyl and N-acyl cyclic ketene-N,N-acetals. The reactions of 2-methylimidazoline with excess benzoyl chlorides in THF or MeCN in the presence of triethylamine generate N,N'-diacyl-beta-keto-cyclic ketene-N,N-acetals. The corresponding reactions of 1,2-dimethylimidazoline under the same conditions form the ring-opened (Z)-3-((2-benzamidoethyl)(methyl)amino)-3-oxo-1-phenylprop-1-enyl benzoates. The latter reactions feature the formation of carbon-carbon bonds, carbon-nitrogen bonds, and carbon-oxygen bonds in one operation. The reactions of 2-methyl-1,4,5,6-tetrahydropyrimidine with excess acid chlorides in Et3N/THF generate N,N-diacyl-cyclic ketene-N,N-acetals, with no further acylation on the exocyclic beta-carbons. In contrast, the reactions of 1,2-dimethyl-1,4,5,6-tetrahydropyrimidine under the same conditions form N-acyl-N'-methyl-beta,beta-diketo-cyclic ketene-N,N-acetals, with the dual acylations on the exocyclic beta-carbons. Significant double bond torsion and elongation were observed by the X-ray analysis of an example compound from the latter reactions. The reactions of 2-methylimidazoline and 2-methyl-1,4,5,6-tetrahydropyrimidine with 1,3-diacid chlorides, in the presence of Et3N in refluxing MeCN give highly functionalized potentially bioactive 1,8-naphthyridinetetraones. 2-Methylimidazoline and 2-methyl-1,4,5,6-tetra-hydropyrimidine can be viewed as tridentate nucleophiles which give four consecutive tandem nucleophilic attacks on electrophiles. The reactions of 1,2-dimethylimidazoline and 1,2-dimethyl-1,4,5,6-tetrahydropyrimidine with isocyanates in refluxing MeCN gave bicyclic pyrimidinediones. The reactions of N,N'-dimethyl cyclic ketene-N,N-acetals with various isocyanates generated push-pull alkenes which have never been reported. Significant elongations and torsions of the polarized carbon-carbon double bonds in the novel push-pull alkenes were observed using the X-ray crystallography. The stronger pushing effect of the six-membered cyclic ketene acetal portion in a push-pull alkene, versus the five-membered analog, was detected by reactivity differences for the first time.

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An investigation into the responses of microbeams to electric actuations is presented. Attention is focused mainly on the use of microbeams in two important MEMS-based devices: capacitive microswitches and resonant microsensors. Nonlinear models are developed to simulate the behavior of the microbeams in each device. The models account for mid-plane stretching, an applied axial load, a DC electrostatic force, and, for the case of resonant sensors, an AC harmonic force. Further, a novel method that uses a reduced-order model is introduced for simulating the behavior of microbeams under a DC electrostatic force. The presented method shows attractive features, like for example, a high stability near the pull-in and a low computational cost. Thus, it can be of significant benefit to the development of MEMS design software. The static behavior of microbeams under electrostatic forces is studied using two methods. One method employs a shooting technique for solving the boundary-value problem that governs the static behavior. The second method is based on solving an algebraic system of equations obtained from the reduced-order model. Further, the eigenvalue problem describing the vibrations of a microbeam around its statically deflected position is solved using a shooting method to obtain the microbeam mode shapes and natural frequencies. The dynamic behavior of resonant microbeams is also investigated. A perturbation method, the method of multiple scales, is used to obtain two first-order nonlinear ordinary-differential equations that describe the amplitude and phase of the response and its stability. The results show that an inaccurate representation of the system nonlinearities may lead to an erroneous prediction of the nonlinear resonance frequency of a microbeam. The case of three-to-one internal resonance between the lowest two modes is treated. Finally, the reduced-order model is used to study the dynamic behavior of the electrostatically actuated microbeams. The proposed models are validated by comparing their results with experimental results available in the literature. / Master of Science

Ten strategically placed push-pull wells were installed to determine in-situ degradation rates at a creosote contaminated site and to assess the contribution of hybrid poplar trees to polynuclear aromatic hydrocarbon (PAH) remediation. Well positioning enabled comparison between contaminated and non-contaminated locations, as well as comparisons between locations with and without trees. Comparison of areas with and without trees enabled an improved understanding of the role that the phytoremediation system has on the overall degradation of PAHs at the site. Bromide, a conservative, non-reactive tracer, was injected in solution along with dissolved oxygen. Twelve push-pull tests (PPTs) were performed, of which three did not include naphthalene in the injection solution, so that the developed method could be evaluated, tested, and yield an initial set of rates to make seasonal and spatial varying in-situ comparisons. Method comparison used for rate analysis found the highest confidence in the method of Snodgrass and Kitanidis (1998) for zero order rates and the method of Haggerty et al. (1998) for first order rates. The largest zero and first order rates, 2.43 mgnaphthalene/L-hr and 1.25 1/hr, respectively, occurred at treed regions in June. Zero and first order winter rates at treed regions were greater by a factor of at least 2.5 when compared to non-treed regions. Degradation rates at treed regions were found to steadily increase by over four times from winter to summer. Results validate that decay variations attributed to phytoremediation can be detected with the push-pull method. PPTs performed at the Oneida site verified observed trends determined from six years of monitoring data, microbial characterization, and microcosm studies. / Master of Science

In many situations, different consumers have different degrees of willingness to wait to get delivery of a product. So, consumers can be segregated based upon the demand lead time they are providing. In this paper, two types of consumers have been considered. The first category needs immediate delivery of the product, so there is no demand lead time; whereas for the other category, demand lead time is positive. A manufacturer, which produces the items using a base stock policy, can benefit from the advance demand information that the second category of consumers are providing. Early fulfillment for a particular order means fulfilling the order before the demand lead time. In this research, it is shown that a restrictive early fulfillment policy can help the firm to reduce the chances of order loss. A production control approach for restrictive early fulfillment is discussed and the factors that may affect the early fulfillment policy are examined. / Master of Science