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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Šiaulių profesinio rengimo centro portalas / Portal of Šiauliai Vocational Education and Training Centre

Šaparauskienė, Lina 03 June 2005 (has links)
Siauliai vocational training centre is an education institution, which prepares a student for vocational career, establishes effective and modern ways of teaching and learning. Siauliai vocational training centre portal is an excellent implement to accomplish these goals. Nowadays explore is of great importance to reach generally used data and documents at any time and place. In the research there were introduced concepts of a portal, analyzed portal’s methods of estimation, accordance with school and teaching portal were investigated. Moreover, there were analyzed the production of informational system with the means of Lotus Domino Designer R6 and their use in setting up an internet portal. It was described the motion of portal modeling too. Portal is made up for Lotus Notes clients and the users of internet by using Lotus Domino Designer elements ( framesets, outlines, pages, forms, subforms, views, agents, image resources, script libraries, combined with Lotus Script, Lotus formulae, JavaScript, HTML programming languages and Java applets). The portal system comprises database of teachers, students, estimation and announcements, and administrator’s module (database performing systemic function). Access to reading/editing documents is set according to the subordination of school commune hierarchy (administration, teachers, students) and roles in the portal system.
62

Rhodium and Palladium Catalysed Domino Reactions of Alkenyl Pyridines and Alkenyl Pyrazines

Friedman, Adam Alexander 22 November 2013 (has links)
Domino catalysis is an ideal strategy in the synthesis of heterocyclic scaffolds, as multiple bonds can be formed under a single set of reaction conditions. In this work, we present the development of two novel domino processes which afford access to aza-analogues of the dihydrodibenzoxepine motif. Careful optimisation revealed that the Rh catalysed hydroarylation proceeds under mild conditions as compared to the C-O coupling. Furthermore, Pd was not required for the C-O bond formation when using alkenyl pyrazines as substrates. Variation of the substituents on both the heterocycle and on the boronic ester provided insight into the structural features required for successful domino reaction, and a stepwise protocol was developed for incompatible substrates. We have also developed the first multi-metal, multi-ligand domino reaction featuring both a chiral and achiral ligand in the same pot, still leading to an enantioenriched product.
63

Rhodium and Palladium Catalysed Domino Reactions of Alkenyl Pyridines and Alkenyl Pyrazines

Friedman, Adam Alexander 22 November 2013 (has links)
Domino catalysis is an ideal strategy in the synthesis of heterocyclic scaffolds, as multiple bonds can be formed under a single set of reaction conditions. In this work, we present the development of two novel domino processes which afford access to aza-analogues of the dihydrodibenzoxepine motif. Careful optimisation revealed that the Rh catalysed hydroarylation proceeds under mild conditions as compared to the C-O coupling. Furthermore, Pd was not required for the C-O bond formation when using alkenyl pyrazines as substrates. Variation of the substituents on both the heterocycle and on the boronic ester provided insight into the structural features required for successful domino reaction, and a stepwise protocol was developed for incompatible substrates. We have also developed the first multi-metal, multi-ligand domino reaction featuring both a chiral and achiral ligand in the same pot, still leading to an enantioenriched product.
64

Stereoselective Synthesis of Nitrogen Containing Compounds from Hydroxy Allylic Azides

Tjeng, Andy 19 November 2013 (has links)
This thesis describes research conducted since September 2006 in Prof. Robert Batey’s laboratory. The thesis is divided into four chapters. Chapter one presents a general introduction of domino reactions, sigmatropic rearrangements, and the allylic azide rearrangement. Several factors affecting the allylic azide rearrangement along with some respective examples are presented. Chapter two describes an efficient synthesis of azido unsaturated ester compounds using a microwave-assisted domino allylic azide / Johnson-Claisen rearrangement. The domino rearrangement reaction proceeds to give the azido ester compounds in good yield and excellent diastereoselectivity. The synthesis of vinyl epoxides and hydroxy allylic azides starting materials are also presented. In addition, other variants of Claisen rearrangements are briefly discussed. Chapter three describes a microwave-assisted domino allylic azide / Overman rearrangement process. The scope of the domino rearrangements, including an example involving an enantioenriched compound, is presented. The product of the domino rearrangements can be used as precursors to 1,2-vicinal diamines. Several functional group transformations and potential application of the product of the domino rearrangement are also described. Chapter four provides the synthesis of cis-2,5-disubstituted pyrrolidines from domino reduction / cyclization of γ-azido-α,β-unsaturated ketones. The overall process involves hydrogenation of the alkene and the azido group, followed by intramolecular cyclization and loss of H2O to form an imine, which is further reduced to give cis-2,5-disubstituted pyrrolidines. The reaction proceeds cleanly to give the products in high yield and with a very high diastereoselectivity ratio. In addition, the formation of pyrrolidinones via domino reduction / cyclication of γ-azido esters are also reported
65

Stereoselective Synthesis of Nitrogen Containing Compounds from Hydroxy Allylic Azides

Tjeng, Andy 19 November 2013 (has links)
This thesis describes research conducted since September 2006 in Prof. Robert Batey’s laboratory. The thesis is divided into four chapters. Chapter one presents a general introduction of domino reactions, sigmatropic rearrangements, and the allylic azide rearrangement. Several factors affecting the allylic azide rearrangement along with some respective examples are presented. Chapter two describes an efficient synthesis of azido unsaturated ester compounds using a microwave-assisted domino allylic azide / Johnson-Claisen rearrangement. The domino rearrangement reaction proceeds to give the azido ester compounds in good yield and excellent diastereoselectivity. The synthesis of vinyl epoxides and hydroxy allylic azides starting materials are also presented. In addition, other variants of Claisen rearrangements are briefly discussed. Chapter three describes a microwave-assisted domino allylic azide / Overman rearrangement process. The scope of the domino rearrangements, including an example involving an enantioenriched compound, is presented. The product of the domino rearrangements can be used as precursors to 1,2-vicinal diamines. Several functional group transformations and potential application of the product of the domino rearrangement are also described. Chapter four provides the synthesis of cis-2,5-disubstituted pyrrolidines from domino reduction / cyclization of γ-azido-α,β-unsaturated ketones. The overall process involves hydrogenation of the alkene and the azido group, followed by intramolecular cyclization and loss of H2O to form an imine, which is further reduced to give cis-2,5-disubstituted pyrrolidines. The reaction proceeds cleanly to give the products in high yield and with a very high diastereoselectivity ratio. In addition, the formation of pyrrolidinones via domino reduction / cyclication of γ-azido esters are also reported
66

Nouvelle méthodologie de synthèse de γ-butyrolactones par une réaction domino métallo-catalysée entre dérivés halogénés, composés carbonylés, et accepteurs de Michael

Le Floch, Camille, Le Floch, Camille 21 November 2011 (has links) (PDF)
Le motif γ-butyrolactone est une entité naturelle très répandue et présente dans de nombreuses molécules à activité biologique. La substitution du cycle à cinq chaînons définit plusieurs classes de composés auxquels les acides paraconiques (portant une fonction acide carboxylique en position β du carbonyle) appartiennent. Ces composés possèdent des activités antitumorales et antibiotiques et représentent une unité structurale intéressante pour la synthèse de molécules à intérêt pharmaceutique. Cependant, la synthèse multicomposant de γ-butyrolactones a été très peu décrite jusqu'à présent. En se basant sur la réactivité sélective des organozinciques aromatiques, il a été supposé qu'une gamme d'acides paraconiques 2,3-polysubstitués pourrait être accessible à partir d'un organozincique, d'un composé carbonylé et d'un accepteur de Michael via une séquence domino métallo-catalysée impliquant la formation de trois liaisons simples par l'intermédiaire d'une addition conjuguée, d'une réaction d'aldolisation et d'une transestérification intramoléculaire aboutissant à la formation du cycle lactone. La réaction développée sur cette base a permis l'accès à une large gamme d'acides paraconiques 2,3-polysubstitués caractérisés par une chaîne benzyle fonctionnalisée en β du carbonyle. Une étude dédiée à la mise en lumière du mécanisme de cette réaction a été effectuée. L'activité antitumorale in vitro de ces composés a été testée sur différentes lignées de cellules cancéreuses (KB, HCT116, MCF7, HL60). Ces tests ont permis de mettre en évidence une molécule à activité intéressante, sur laquelle des tests supplémentaires ont été effectués (PC3, SK-OV3, MCF7R, HL60R, MRC5, EPC, mécanisme d'action) et des IC50 de 0,6 à 6 µM ont été mesurées sur la plupart de ces lignées. Une extension de la réaction à partir de dérivés ortho-bisubstitués a permis d'obtenir une gamme de lactones tricycliques ortho-condensées avec de bons rendements et de manière diastéréosélective, par un procédé domino. Ces différents composés présentent le motif tricyclique ABC, caractéristique de la structure des strigolactones, hormones jouant un rôle fondamental dans le processus de germination des plantes
67

Rhodium and Palladium Catalysis in the Synthesis of Carbo- and Heterocycles

Panteleev, Jane 18 December 2012 (has links)
This thesis describes the development of transition metal catalyzed transformations towards the synthesis of stereochemically rich motifs and heterocycles. The main themes present throughout this thesis are rhodium-catalysis in reactions of boronic acids with alkenes and alkynes, the use of alkynes as a key motif in the synthesis of heterocycles, and the use of domino and one-pot processes to effect high efficiency in multistep transformations. In Chapter 1, a rhodium-catalyzed desymmetrization of diazabicyclic alkenes with boronic acids is discussed. In this work a chemodivergent and enantioselective process for the synthesis of substituted cyclopentenes and cyclopentanes is developed. Both the chemo- and the enantioselectivity of the reaction are shown to be highly dependent on the phosphine ligand structure. The observed reactivity of rhodium is further applied to a domino reaction to synthesize highly substituted benzofuranones. In Chapter 2, the reactivity of boronic acids and alkynes under rhodium catalysis is exploited as a key step to access polycyclic motifs. In the first part of this chapter the development of a domino process using both rhodium and palladium catalysis is described. Detailed mechanistic investigations allow some insight into the interactions between two catalysts. In the last part of this chapter, preliminary experiments in the application of multimetallic catalysis in the synthesis of azadibenzoxepines are discussed. Chapter 3 summarizes work on the arylation of propargylic alcohols with boronic acids under rhodium catalysis. This reaction is shown to proceed with high regioselectivity and can be conducted under mild conditions. The resulting allylic alcohols are shown to be versatile motifs and are applied in a synthesis of indenes and quinolines. In the final chapter of this thesis, iodotriazoles are explored as key intermediates in the synthesis of fused triazole-containing heterocycles. Palladium-catalyzed cyclization, either through C-H functionalization or through Heck coupling, is achieved. Furthermore, it is shown that the copper-catalyzed azide-alkyne cycloaddition and palladium-catalyzed C-H arylation can be combined into a one-pot process.
68

Etude de la vulnérabilité de structures cylindriques soumises à une forte explosion externe / Study of the vulnerability of cylindrical structures subjected to strong external explosion

Duong, Duy-Hung 23 March 2012 (has links)
Ce travail s'inscrit dans le contexte de l'évaluation et de la prévention des risques d'effets dominos suite à une explosion sur un site industriel. Il s'intéresse plus précisément à la vulnérabilité de réservoirs de stockage soumis à une onde de souffle. Le mode d'explosion étudié est celui de la détonation gazeuse. L’objectif est double. Il consiste d'une part à caractériser le chargement auquel est soumis le réservoir et d'autre part à prédire la réponse du réservoir à ce chargement. Des expérimentations ont été réalisées à échelle réduite, pour trois géométries caractéristiques de réservoirs, satisfaisant des conditions de similitudes énergétiques et mécaniques. Des essais sur maquettes de réservoirs rigides ont permis de caractériser le chargement issu d'une détonation : répartition spatio-temporelle de la surpression et de l’impulsion et détermination de coefficients de réflexion. Des essais sur maquettes métalliques déformables ont permis de déterminer le niveau de chargement nécessaire pour endommager la structure par flambage. Une approche semi-analytique du flambage dynamique basée sur une modélisation simplifiée du chargement de surpression de type Friedlander associée à un modèle de coque élastique surbaissée de Donnell et à la croissance d'imperfections géométriques jusqu'à une taille critique a été développée. Son application permet la construction des courbes critiques de flambage des réservoirs métalliques dans des diagrammes pression-impulsion. La confrontation entre les résultats expérimentaux et les prédictions numériques souligne l'intérêt et la pertinence de la démarche proposée. / This work is a contribution to the assessment and prevention of potential domino effects caused by an explosion in an industrial area. It focuses specifically on the vulnerability of storage tanks subjected to a blast wave. Within this context, we investigate the effects of gaseous detonation. The objective is twofold: on one hand, to characterize the blast loading and, on the other, to predict the structural response. Three representative atmospheric chemical tanks were selected. Experiments were conducted at small scale satisfying Hopkinson-Cranz and structural scaling laws. A first campaign was performed on rigid instrumented cylinders to quantify the loading in terms of time and space pressure distribution. A second campaign was performed on flexible cylinders to quantify the structural response in terms of dynamic buckling damage. Simplified semi-analytical models were developed to provide damage predictions. They are based on a Friedlander pressure-time history pulse description, shallow-shell (Donnell's) equations and critical shape imperfection amplification thresholds. These models are used to construct pressure-impulse buckling damage diagrams for atmospheric tanks subjected to blast loading. The comparison between experimental results and numerical predictions highlights the interest and the relevance of the proposed approach.
69

EFFICIENT DESIGN OF CARRY SELECT ADDER USING DOMINO MANCHESTER CARRY CHAIN

Meruguboina, Dronacharya 01 May 2017 (has links)
Significant characteristic of any VLSI design circuit is its power, reliability, operating frequency and implementation cost. Dynamic CMOS designs provide high operating speeds compared to static CMOS designs combined with low silicon area requirement. This thesis describes the design and the optimization of high performance carry select adder. Previous researchers believed that existing CSA designs has reached theoretical speed bound. But, only a considerable portion of hardware resources of traditional adders are used in worst case scenario. Based on this observation our proposed design will improve on theoretical limit. The major scope of this proposed design is to increase the speed of carry generation between intermediate blocks of Carry select Adder (CSA) by introducing fast multiple clock Domino Manchester carry chain (MCC) that generates carry outputs. This design technique will have some advantages compared to pre-existing implementations in operating speed and power delay product. Simulation has been done using GPDK (Generic Process Design Kits) technology using cadence virtuoso. Thus the proposed technique provides advantages over pre-existing techniques in terms of operating speed.
70

O jogo dominó algébrico / The game algebraic domino

Franco, Felipe Barbosa 03 April 2018 (has links)
Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2018-06-29T10:56:16Z No. of bitstreams: 2 Dissertação - Felipe Barbosa Franco - 2018.pdf: 2597060 bytes, checksum: b4c3ff56766b29c5a01cd7de1c3ba60a (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-06-29T11:55:57Z (GMT) No. of bitstreams: 2 Dissertação - Felipe Barbosa Franco - 2018.pdf: 2597060 bytes, checksum: b4c3ff56766b29c5a01cd7de1c3ba60a (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-06-29T11:55:57Z (GMT). No. of bitstreams: 2 Dissertação - Felipe Barbosa Franco - 2018.pdf: 2597060 bytes, checksum: b4c3ff56766b29c5a01cd7de1c3ba60a (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-04-03 / This work is theoretical, and its methodology was initially based on the research and bibliographic review of the Euclidean Algorithm, as well as the use of games in Mathematics education. A proposal was elaborated for the 7th year of Middle School, based on the Algebraic Dominoes of Freitas-Teodoro [8]. This proposal follows the methodology of Souza [22], which has lesson plans defined in four different moments. An analysis was made to justify the efficiency and importance of the Adapted Algebraic Domino restricted to the Use of Games in education based on the work of authors Regina Grando [10], Kishimoto [13], [14], [15], [16], [17] and Cristiano Muniz [18]. In addition, some simulations of plays related to the Algebraic Domino were made, for better understanding of the proposed subject. / Este trabalho é de cunho teórico, cuja metodologia baseou-se inicialmente na elaboração de pesquisas e revisões bibliográficas sobre o Algoritmo de Euclides, bem como sobre do Uso de Jogos no ensino de Matemática. Foi elaborada uma proposta inédita para o Sétimo Ano do Ensino Fundamental com base no Dominó Algébrico de Freitas-Teodoro [8]. Essa proposta segue a metodologia de Souza [22], que tem planos de aula definidos em quatro Momentos. Foi realizada uma análise para justificar a eficiência e importância da proposta do Dominó Algébrico Adaptado restritas ao Uso de Jogos no ensino com base em obras dos autores Regina Grando [10], Tizuko Kishimoto [13], [14], [15], [16], [17] e Cristiano Muniz [18]. Ademais, foram realizadas algumas simulações de jogadas relativas ao jogo Dominó Algébrico para melhor elucidação do tema proposto.

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