Typescript (photocopy).

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 61-70). Also available via the Internet.

Le but de ces travaux est de mettre en application les caractéristiques particulières des microréacteurs en flux dans le cadre de la synthèse organique. Ces particularités sont expliquées dans l’avant-propos de ce manuscrit, afin de comprendre comment elles peuvent influencer le déroulement d’une réaction. La première partie de ces travaux de thèse concerne l’emploi des réacteurs microfluidiques pour la génération de carbénoïdes vinyliques hautement instables (avec des demi-vies souvent inférieures à la seconde), et leur emploi en synthèse. Même si des conditions de génération efficaces ont été mises au point, le piégeage d’électrophiles variés reste difficile en raison des cinétiques extrêmes mises en jeu. La seconde partie décrit la neutralisation d’agents de guerre chimique (CWA), avec une emphase sur la possibilité d’augmentation d’échelle et la sécurité. Des voies de neutralisation oxydantes ont été explorées sur des thioethers de type hémimoutardes (sulfures de 2-chloroéthyle), analogues de l’ypérite. La méthode développée offre une conversion en sulfoxyde quantitative, et ne produit que des effluents bénins à partir de réactifs disponibles et abordables. Cette méthode d’oxydation en flux a pu être extrapolée rapidement et facilement sur une quantité importante d’hémimoutarde (25g), et couplée à une analyse RMN en ligne. L’applicabilité de cette méthode à des phosphonothioates a également été envisagée. Constituants majoritaires de la série V, ces molécules organophosphorés neurotoxiques peuvent également être neutralisées par l’oxydation sélective d’un atome de soufre. Pour réaliser cette étude, une nouvelle voie d’accès au motif phosphonothioate a été explorée avec succès. Ceci a permis la synthèse du PhX (analogue phénylé proche du VX), ainsi que d’autres analogues pertinents de la série V. Cette méthode offre un rendement élevé à une échelle adaptée au laboratoire, et permet un accès très rapide au produit final. La réactivité de ces modèles a ensuite pu être évaluée vis-à-vis de divers oxydants. Une méthode unique n’a pour le moment pas pu être développée, mais la compréhension plus poussée des mécanismes oxydants impliqués dans ces processus pourrait permettre de répondre prochainement à ce défi. / The goal of this work was to put in application the unmatched properties of fluidic microreactors in the field of organic synthesis. Those particular properties are discussed in this document, in an attempt to rationalize their effects on reaction courses. The first part of this work is dedicated to exploiting unstable vinylic carbenoids as nucleophiles despite their very short half-lives (often inferior to the second). Even if some results show efficient trapping of those elusive intermediates, applicability in synthesis remains very limited because of the extreme nature of the kinetics involved. The second part describes the application of microreactors to neutralization of chemical warfare agent (CWA) with an emphasis on scalability and safety. Oxidative neutralization pathways were explored on half-mustard thioethers (2-chloroethyl sulfides), as yperite simulants. The developed method allows their full conversion to sulfoxides, and only produces non-toxic effluents. This oxidative method was easily scaled up to 25g of half-mustard, and was successfully coupled with an in-line NMR analysis.Effectiveness of this method on phosphonothioates was also explored. These neurotoxic organophosphorus molecules, which are the majority constituents of the V series, can also be neutralized by the selective oxidation of a sulfur atom. To perform this study, a new pathway to phosphonothioate moiety was successfully explored. This allowed a new synthetic path for PhX (a close, phenyl analogue of VX), along with other relevant V series analogues. This method offers good yields at lab scale, in an expedient fashion. Reactivity of these CWA simulants was then evaluated against multiple oxidants. Even if a unified method could not yet be developed, a better understanding of the involved oxidative mechanisms could allow to address this challenge.

This research was originally conceived under the auspices of the UK Government's Foresight Initiative, which aimed to translate the significant body of process tomography knowledge, residing in various British universities, towards applications of generic benefit to industry. In collaboration with the sponsoring life science company, Zeneca Ltd, a number of potential demonstrator projects were identified. Ultimately on-line imaging within pressure filtration was selected by virtue of its direct and broad benefit to the chemical sector and the opportunity to extrapolate the techniques developed towards other batch production processes. The research programme is centred around three empirical studies. These progress from an initial phase, where the early laboratory instrumentation was exposed to a constrained set of filtration conditions, through to the installation of a novel prototype industrial tomography system on to an existing large scale production unit, which was fabricated from an electrically conducting alloy and located in a potentially flammable atmosphere. During the course of these investigations electrical impedance tomography (EIT) was identified as the most viable modality for this class of application. The challenges associated with transferring the EIT technology into the manufacturing environment were addressed by taking advantage of the lenient frame rates acceptable within chemical batch monitoring to develop an instrument structure which was intrinsically safe, suitable for use with earthed metal vessels, tolerant to chemically aggressive media and amenable to three-dimensional image reconstruction via irregular, process compliant, electrode architectures. In the subject production filter a planar sensor array was exploited to provide a relatively uniform electrical field distribution within the process material, whilst not adversely affecting the normal operation of the plant item.

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Thesis--Otaniemi. / Thesis statement for v. C. Vol. A has summary in English. Includes bibliographical references.

The purpose of this report is to describe the course, Analysis of the Real Line, taught at The University of Texas at Austin. Course materials are presented using the inquiry based learning method. Students work a series of warm up problems before being presented rigorous problems in calculus, including topics on integration, exponential functions, and real number line analysis. Additionally, students consider aspects of these problems that could be incorporated into a high school curriculum. Typical problems in several major areas are summarized along with warm up problems that introduce or extend the topics. / text

No description available.

Four rectangular, isotropically reinforced concrete slabs were constructed and loaded until collapse. All slabs were fixed on three edges with the fourth edge free. Three slabs contained openings at various locations while the fourth remained solid. The magnitudes of deflections were measured during loading and the final yield pattern and ultimate load were compared to those predicted by simple and advanced yield-line theory. An analytical computer program was developed and is presented for quick evaluation of the ultimate load and collapse mode of many types of uniformly loaded slabs by simple yield-line theory. Short specialized programs were also formulated to analyze the experimental slabs, considering the presence of simple corner levers and edge loads around the openings. This resulted in more accurate theoretical predictions and produced estimates of the percent difference between simple and advanced theory predictions. Analysis of the results showed excellent agreement between the advanced theory predictions and the experimental results. / M.S.

Concrete bridge rails are rated according to three performance levels. For classification at a given performance level, the rail must meet specific strength and geometric requirements. To meet the strength requirement, the rail must be able to satisfactorily withstand a transverse concentrated load applied at the top of the rail. This load is called F_t (kips) and is listed for each performance level in the Draft NCHRP Project 12-33 document entitled Development of a Comprehensive Bridge Specification and Commentary. Researchers at the Texas Transportation Institute have developed equations to determine R_w (kips), the total transverse resistance of a rail (which must be greater than or equal to F_t), and L_c (ft), the critical length of wall failure (Hirsch 1978). These equations (referred to as Hirsch equations is this study) were developed by yield line analysis for a constant thickness concrete parapet wall. The purpose of this study is to develop similar equations for R_w and L_c based on yield line analysis of a variable thickness New Jersey concrete parapet wall instead of a constant thickness wall. The results from this study indicate that the Hirsch equations significantly over estimate R_w for variable thickness concrete walls where M_c, the flexural resistance of the wall about the horizontal axis, varies substantially over the height of the wall. This study recommends that an average value for M_c, taken over the height of the wall, be used in the Hirsch equations when this situation arises. / Master of Science