• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 82
  • 24
  • 23
  • 18
  • 13
  • 13
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 183
  • 92
  • 70
  • 57
  • 23
  • 22
  • 19
  • 16
  • 16
  • 16
  • 15
  • 13
  • 13
  • 12
  • 12
  • 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.
71

Výroba mostního bednění PREWAG / Mode of production of PREWAG bridge concrete

Chalupa, Karel January 2011 (has links)
This diploma thesis introduces manufacturing documentation needed for the production of a PREWAG welded steel structure. It deals with the execution of the welds as well as with the construction execution and the technological and welding procedure in the production. A selection of drawing documentation and particular WPS techniques is included.
72

Navigationskonceptet DSI:s påverkan på användarupplevelsen : En studie av en elektronisk turistbroschyr / The navigation concept DSI's impact on the user experience : A study of an electronic tourist brochure

Raattamaa, Lena, Ghazali, Mirna January 2015 (has links)
En turistbroschyr är en bekant produkt som turister kan hämta information ifrån. Men hur upplever användarna interaktionen med ett obekant navigationskoncept som vi kallar DSI i kontexten av att söka turistinformation och vad har DSI för påverkan på användarupplevelsen? Vi har utfört en studie på tio respondenter. Studien inkluderar en observation där respondenterna har fått interagera, med applikationen vi skapade med navigationskonceptet DSI, och utföra ett antal uppgifter. De har även fått utföra ett antal uppgifter på en PDF med samma innehåll men med en annan struktur. Därefter utförde vi metoden Product Reaction Cards och till sist en intervju. Vi kom fram till att det tar tid att lära sig någonting obekant som DSI men när respondenterna väl har lärt sig konceptet så har det haft en positiv påverkan på användarupplevelsen och majoritet ansåg den som användbar i kontexten av att söka turistinformation. / A tourist brochure is a familiar product that tourists collect information from. But how do users experience the interaction with an unfamiliar navigation concept we call DSI in the context of seeking tourist information and what impact does DSI have on the user experience (UX)? We conducted a study of ten respondents. The study includes an observation in which the respondents had to interact with the application we created with the navigation concept DSI, and perform a number of tasks. They also performed a number of tasks on a PDF with the same content but with a different structure. Afterwards we performed the method Product Reaction Cards and lastly an interview. We concluded that it takes time to learn something unfamiliar as DSI but when the respondents have learned the concept it turned out to have a positive impact on the user experience and the majority considered it useful in the context of seeking tourist information.
73

Rôle des Résolvines, dérivés trihydroxylés du DHA et de l'EPA, dans la résolution de l'inflammation pour la prévention de l'hypertension artérielle pulmonaire

Hiram, Roddy January 2016 (has links)
Résumé : L’hypertension artérielle pulmonaire (HTAP) est une maladie rare dans laquelle les artères pulmonaires subissent un important remodelage et un recrutement de cellules proinflammatoires dans la paroi. Généralement les patients atteints sont diagnostiqués tardivement. Or, à son stade avancé, l’HTAP est irréversible. Aucun traitement actuel ne permet de soigner définitivement les patients. Nous émettons l’hypothèse que l’inflammation pourrait être à l’origine de plusieurs dysfonctions cellulaires et que sa résolution pourrait probablement prévenir l’HTAP. Deux modèles d’HTAP expérimentale ont été utilisés. Le premier met en jeu des artères pulmonaires humaines (APH) cultivées in vitro et rendues hyperréactives et sur lesquelles les effets des Résolvines D1 et E1 ainsi que leurs précurseurs respectifs ont été évalués. Le deuxième est un modèle in vivo bien connu de rats hypertendus à la monocrotaline (MCT) sur lesquels le rôle curatif du MAG-DHA (un monoacylglycéride de l’acide docosahexaénoïque) a été étudié quand l’HTAP est déjà installée. Les résultats démontrent que 24 h de prétraitement in vitro avec le TNFalpha, l’IL-6 ou l’ET-1 augmente la réactivité pharmaco-mécanique et la sensibilité au Ca2+ des APH stimulées avec 80 mM de KCl, 1 µM de 5-hydroxytryptamine (5-HT), 30 nM U-46619 et 1 µM de PDBu. En revanche, 300 nM de RvD1 ou de RvE1 ainsi que 1µM de MAG-DHA ou de MAG-EPA (monoacylglycéride de l’acide éicosapentaénoïque) renversent les effets induits par les traitements proinflammatoires et vasoconstricteurs. De plus, in vivo, il a été démontré que 7 jours de traitement avec le MAG-DHA peuvent permettre de résoudre le statut inflammatoire dans un modèle d’hypertension pulmonaire induite par la MCT chez le rat. Dans les deux modèles, l’expression de biomarqueurs inflammatoires (TNFalpha, COX-2, STAT3) et les niveaux de phosphorylation des activateurs nucléaires du remodelage tels que c-Fos, c-Jun, NFkB et MMP9 étaient augmentées par les traitements proinflammatoires. Cependant, les expériences d’immuno-buvardage montrent que la RvD1, la RvE1 et leurs précurseurs normalisaient les niveaux de détections de ces marqueurs de l’inflammation. En conclusion, l’ensemble des données montrent que les Résolvines D1 et E1 ainsi que leurs précurseurs sont des candidats efficaces pour résoudre l’inflammation induite pour prévenir l’hyperréactivité pharmacologique des artères pulmonaires. / Abstract : Pulmonary hypertension (PH) is rare disease characterized by an important remodelling and proinflammatory cells recruitement into the pulmonary artery wall. Because of the late diagnostic, the patient care is often performed when PH is at its irreversible and most severe stage. Unfortunatly, none of the actual treatments are able to cure the patients for the long term. We hypothesize that inflammation could be a major event at the origin of all the other cellular dysfunctions that characterise PH. Resolvins; metabolites from Oméga-3 could resolve inflammation and potentially prevent or reverse PH. In the present study, two models of PH have been used. The first one is an in vitro model involving cultured human pulmonary arteries (HPA) in which inflammatory or hyperreactive conditions have been induced to evaluate the effects of Resolvin D1 and E1 and their precursors. The second model is a well-known in vivo model of monocrotalineinduced PH in rats, treated with MAG-DHA (monoacylglyceride form of docosahexaenoic acid) to evaluate the curative ability of this compound to resolve the disease at its severe stage. Results show that 24-h pre-treatment with TNFα, IL-6 or ET-1 increased the reactivity and Ca2+ sensitivity of HPA as revealed by agonist challenges with: 80 mM KCl, 1 μM 5- hydroxytryptamine (5-HT), 30 nM U-46619 and 1 μM PDBu. However, 300 nM RvD1 or RvE1, as well as 1 μM MAG-DHA or MAG-EPA (monoacylglyceride form of eicosapentaenoic acid) strongly reversed the over responsiveness induced by proinflammatory and hyperreactive treatments.Moreover, a 7-day treatment with MAG-DHA is able to resolve the inflammatory status in a rat model of monocrotaline-induced pulmonary hypertension. In both models, the inflammatory status enhanced the expression of inflammatory biomarkers (TNF-α, COX-2, STAT-3) as well as the detection of MMP9 and phosphorylated nuclear factors such as P-c-Fos, P-c-Jun and P-NF-κB involved in the activation of wall remodeling. Hence, RvD1, RvE1 and their precursors normalized the expression of these inflammatory biomarkers. In conclusion, Resolvin D1 and E1 and their respective precursors MAG-DHA and MAGEPA could inhibit inflammation status to prevent and potentially cure pulmonary hypertension.
74

Digitala publikationer : Nästa steg i tidningens utveckling / Digital publications : The next step in the magazine's development

Lange, Josefin January 2012 (has links)
Denna rapport beskriver hur dagens tekniska processer ser ut vid tillverkning av applikationer för interaktiva publikationer. En interaktiv publikation är en digitalt skapad tidning med ett extra lager av information som man kan interagera med. Exempel på interaktivitet är bildspel, video och informationsflöden i realtid som visas direkt i tidningen.  Rapporten fokuserar på vad det är som ger ett mervärde till en digital interaktiv publikation och vilka funktioner det är som kan ge upphov till detta. Genom en jämförande analys mellan digitala publikationer och papperstidningar tas fyra designaspekter fram för att användas som grund för hur interaktiva element bör hanteras i framställningen av digitala publikationer.  En prototyp av en interaktiv publikation har tagits fram för att visa hur designaspekterna kan tillämpas och för att visa hur information kan presenteras på ett mer interaktivt sätt. / This report describes how today's technological processes look like in the production of applications for interactive publications. An interactive publication is a digitally created magazine with an extra layer of information that you can interact with. Examples of interactivity is slideshows and video and data streams in real time that are displayed directly in the magazine. The report focuses on what it is that adds value to a digital interactive publication, and what functions which may provide cause to this. Through a comparative analysis of digital publications and the newspapers, four designaspects have been developed as an basis for how the interactive elements should be handled in the production of digital publications.  A prototype of an interactive publication was developed to show how the designaspects can be applied and to show how information can be presented in a more interactive way.
75

Irritable bowel syndrome diagnosed in primary care : occurrence, treatment and impact on everyday life /

Olsen Faresjö, Åshild, January 2006 (has links)
Diss. (sammanfattning) Linköping : Linköpings universitet, 2006. / Härtill 5 uppsatser. NB: Rätt ISBN från spikblad.
76

Neuropathies périphériques et hémopathies B : de l'étude clinique des neuropathies associées à une gammapathie monoclonale IgM à activité anti-MAG au mécanisme de mort cellulaire induit par le Fingolimod (FTY720) dans les hémopathies B / Peripheral neuropathy and B cell malignancy : anti MAG neuropathy and cell cytotoxicity induced by FTY720 in chronic lymphocytic leuckemia

Delmont, Émilien 26 November 2013 (has links)
Les neuropathies à anticorps anti-MAG sont secondaires à une gammapathie monoclonale IgM dirigée contre la MAG des gaines de myéline des nerfs périphériques. Le traitement est celui de l’hémopathie sous‐jacente. Même si les thérapeutiques sont de plus en plus efficaces, les hémopathies restent le plus souvent incurables. Le rituximab est couramment utilisé dans le traitement des neuropathies à anticorps anti‐MAG, mais son efficacité n’a pas pu être clairement démontrée dans deux études contrôlées. Le FTY720 ou fingolimod est un sphingolipide, analogue de la sphingosine, qui inhibe les récepteurs de la sphingosine-1-phosphate (S1P). Il est utilisé comme immunosuppresseur dans la Sclérose en Plaques. Des études ont également rapporté un effet cytotoxique du FTY720 dans des hémopathies sans toutefois clairement expliquer son mécanisme d’action. L’objectif de ce travail est d’élucider les mécanismes moléculaires de l’effet cytotoxique du FTY720 dans un modèle d’hémopathie B, la leucémie lymphoïde chronique (LLC). Des cellules leucémiques primaires de LLC et une lignée cellulaire MEC1 ont été utilisées comme modèle expérimental in vitro. Le FTY720, comme la sphingosine, entraîne une cytotoxicité dose‐dépendante dans la LLC. Cet effet, médié par la forme non phosphorylée de FTY720, est indépendant des récepteurs au S1P. Le FTY720 induit l’expression de marqueurs d’apoptose: exposition de la phosphaJdylsérine, clivage de PARP et de caspase 3. Cependant sa toxicité apparaît indépendante des caspases. La lipidation accrue de LC3 et la formation d’autophagolysosomes indiquent que le FTY720 augmente également le flux autophagique. Cependant, des inhibiteurs de l’autophagie ne permettent pas de bloquer la mort cellulaire induite par le FTY720, suggérant que l’autophagie a ici un rôle protecteur vis à vis de la toxicité du FTY720. Plusieurs éléments permettent de conclure que le FTY720 est responsable d’une nécrose cellulaire : aspect morphologique de nécrose en microscopie électronique, perméabilisation membranaire précoce avec relocalisation cytoplasmique de HMGB1, libération extracellulaire de LDH, perméabilisation de la membrane lysosomale associée à une activation des cathepsines. Au niveau moléculaire, l’action du FTY720 n’est pas bloquée par la nécrostatine 1, indiquant que la nécrose induite par le FTY720 est indépendante de RIPK1 (receptor interacJng protein 1), une kinase clef des voies extrinsèques de nécrose cellulaire programmée. Par contre, nos travaux ont établi l’implication de DRP1 (dynamin related protein), une enzyme régulatrice de la fission mitochondriale, dans le processus de nécrose induite par le FTY720. En plus d’une relocalisation précoce de DRP1 à la mitochondrie accompagnée d’une augmentation de sa phosphorylation sur des sites régulateurs de son activité, nos expériences montrent que la suppression de son expression par interférence à ARN dans les cellules leucémiques réduit fortement la mort cellulaire induite par le FTY720. Le FTY720 est donc responsable dans la LLC d’une nécrose cellulaire programmée dépendante de DRP1. Nos résultats illustrent l’implication des sphingolipides dans la régulation de la survie cellulaire et dans les voies de nécrose programmée. Le FTY720 a un mode d’action original différent de l’apoptose induite par les chimiothérapies classiques. Le FTY720 pourrait donc être une alternative thérapeutique dans les néoplasies B résistantes aux chimiothérapies usuelles et dans certaines manifestations auto‐immunes des hémopathies comme les neuropathies à anticorps anti‐MAG. / Fingolimod (FTY720) is an immunosuppressive drug that was recently approved for the treatment of multiple sclerosis and is currently under pre-clinical investigation as a therapy for a number of haematological malignancies. Previous studies have indicated a role for FTY720 in inducing autophagy and caspase-independent cell death in cancer cells through incompletely characterized molecular mechanisms. Our study thus aims at a beeer understanding of the way of action of FTY720. In chronic lymphocytic leukaemia (CLL) cells, FTY720 induced cell death with typical features of apoptosis, including phosphatidylserine exposure and caspase-3 activation, and features of autophagy, including LC3 conversion, autophagolysosome formation and lysosomal cathepsins activation. However, neither caspase nor autophagy blockade prevented the cytotoxic effect of FTY720, suggesting another mechanism of cell death. Using electron and fluorescence microscopy, flow cytometry and biochemical analyses, we found that FTY720 treatment increased a fraction of annexin V-/7-AAD+ cells both in primary and transformed leukemic cells and induced morphological changes representative of necrosis, including oncosis, mitochondrial and plasma membrane alteration. FTY720 treatment resulted in increased plasma membrane permeability as shown by the extracellular translocation of the nuclear high mobility group box 1 (HMGB1) protein and by the release into the culture medium of the cytosolic enzyme lactate dehydrogenase (LDH). Interestingly, cell death induced by FTY720 was not prevented by pharmacological inhibition of RIPK1 and PP2A. In contrast, FTY720--‐induced necrosis was accompanied by an early relocation to the mitochondria of Dynamin Related Protein 1, DRP1. Importantly, FTY720 stimulation led to ma tior changes in the phosphorylation of serine residues associated with the mitochondrial fission activity of DRP1. Finally, siRNA--‐mediated knockdown of DRP1 significantly reduced necrotic cell death induced by FTY720. In this study, we thus demonstrate that in leukemic cells the cytotoxic effect of the immunosuppressive drug Fingolimod involves a DRP1--‐dependent regulated necrosis. These observations are important in line of the future development of Fingolimod as a new therapeutic agent in haematological malignancies.
77

Publicidade e moda: um estudo sobre a materialidade da m?dia e a produ??o de sentido na revista ffw>>mag!

Moura, Nayana Gurgel de 16 September 2013 (has links)
Made available in DSpace on 2014-12-17T15:08:34Z (GMT). No. of bitstreams: 1 NayanaGM_DISSERT.pdf: 3639908 bytes, checksum: 068d2520cb24980c9518d5d6f0d255fe (MD5) Previous issue date: 2013-09-16 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The proposal of this research is to analyze the convergence between fashion and communication shown on the materiality of the print media, and how the language from the supporter influences on the production of sense by the target market. Made real in the research corpus comprised of six ffw>>mag! magazines from the year 2011. The applied conceptual mechanism tries to investigate the production of sense from the physical attributes before interpreting the message s content, to do so, the Materiality of Communication is used, which offers an investigative apparatus of the media in its material shape, and those as influences in the communicative acts and processes. Methodologically, we adopt the Peircean Semiotics Theory, for its study focus on the analysis of the possible processes of production of sense. Through Semiotics we achieve the interpretative levels that allow us to clarify the questionings that come from the research s objectives, identifying and tracing the cognitive and intelligibility schemes bound to the media speeches of materiality. The analysis coordinated to the concepts and theories employed in this study point to a confirmation that the materiality of the reviewed media communicates to the readers in the same intensity as its content, provides a preview of the content and notifies the intentions of the publication. In the commercial way, characterizing the target audience it craves, and also in the conceptual way, demonstrating the ideas it wants to communicate. Where the convergence between communication and fashion unfolds as the materiality of the media by the choice of the materials and finishing options, and mainly by the selection and manipulation of technical images and colors from the cycles of fashion / A presente pesquisa se prop?e a analisar a converg?ncia entre comunica??o e moda, que se manifesta na materialidade da m?dia impressa, e como a linguagem proveniente desse suporte influencia na produ??o de sentido por parte do p?blico alvo, que se concretiza no corpus de pesquisa composto por seis revistas ffw>>mag! referentes ao ano de 2011. O mecanismo conceitual aplicado busca investigar a produ??o de sentido partindo das caracter?sticas f?sicas antes de se interpretar o conte?do da mensagem. Para tanto, empregamos a Teoria das Materialidades da Comunica??o, que oferece um aparato investigativo dos meios em seu car?ter material, e estes como influ?ncia nos processos e atos comunicativos. Metodologicamente, adotamos a Teoria Semi?tica de origem peirceana, uma vez que seu foco de estudo reside na an?lise dos poss?veis processos de produ??o de sentido. Por meio da Semi?tica, alcan?amos os n?veis interpretativos que permitam solucionar as indaga??es provenientes dos objetivos da pesquisa, identificando e delineando os esquemas cognitivos e de inteligibilidade vinculados aos discursos provenientes da materialidade da m?dia. As an?lises articuladas aos conceitos e teorias empregados neste trabalho apontam para a confirma??o de que a materialidade da m?dia revista comunica aos leitores na mesma intensidade que seu conte?do. Ela disponibiliza uma pr?via do conte?do e informa as inten??es da publica??o, tanto pelo lado comercial, caracterizando o p?blico consumidor que ela almeja, quanto do lado conceitual, demonstrando as ideias que deseja transmitir, onde a converg?ncia da comunica??o com a moda se manifesta na materialidade da m?dia por meio da escolha dos materiais e formas de acabamentos e principalmente pela sele??o e manipula??o de imagens t?cnicas e cores provenientes dos ciclos da moda
78

Avaliação cinemática e dinâmica da transferência metálica na soldagem mig/mag / Dynamic and cinematic evaluation of MIG/MAG metal transfer

Rodrigues, Carlos Eduardo Aguiar Lima 19 October 2007 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / The goal of this work is to improve the knowledge of the metal transfer in MIG/MAG welding and supply data to improve the elaboration of its models. In this intention, experiments were accomplished with steel (inverse polarity; Ar+5%O2 shield gas) and aluminum (inverse polarity, Ar shield gas) electrodes, with steel electrode and several shield gases (inverse polarity, Ar+5%O2+ of 0 to 25%He shield gases) and experiments with steel electrode in direct polarity (Ar+5%O2 shield gas). The flat position welds were filmed by a high-speed video camera using the shadowgraph technique. Kinematics and dynamics characteristics of metal transfers in those experiments were obtained experimentally (droplets arrival speed in the weld pool, in flight droplets average acceleration, effective quantity of movement), and the weld geometry, and compared whenever possible with experimental and numeric results available in literature. The results showed that the weld current influences the kinematics and dynamics characteristics of the drops in all of studied conditions, that the arc length influences the cinematic characteristics and dynamics in the welds with steel and aluminum electrodes, and in the steel welds with different shield gasses; that the shield gas doesn't exercise significant influence in the appraised characteristics, and that the current polarity only affects the cinematic characteristics and dynamics in globular transfer mode. Additionally, the welding current affects the weld penetration despite the use of approximately the same heat input, the arc length affect the steel and aluminum weld penetration and with different shield gasses, the shield gas didn't exercise influences in the values of the penetration but it altered the form of the weld and the current polarity didn't exercise influences the weld penetration, but just in width and reinforcement, being more slender the weld bead in direct polarity. / Com o intuito de aprofundar o conhecimento da transferência metálica em MIG/MAG goticular e fornecer dados para aprimorar a elaboração de modelos da mesma, foram realizados experimentos com eletrodos de aço (polaridade inversa, gás de proteção Ar+5%O2) e alumínio (polaridade inversa, gás de proteção Ar), experimentos com eletrodo de aço e vários gases de proteção (polaridade inversa, gases de proteção Ar+5%O2+de 0 a 25%He), e experimentos com eletrodo de aço em polaridade direta (gás de proteção Ar+5%O2). As soldas, em posição plana, foram filmadas em alta velocidade através da técnica da perfilografia. Determinou-se experimentalmente características da transferência metálica (diâmetro das gotas e sua freqüência de destacamento e o comprimento do arco elétrico), bem como as características cinemáticas e dinâmicas das transferências metálicas obtidas nesses experimentos (velocidade de chegada das gotas à poça de fusão; aceleração média das gotas durante a trajetória; quantidade de movimento efetiva das gotas) e a geometria dos cordões de solda, comparados sempre que possível a resultados experimentais e numéricos disponíveis na literatura. Os resultados mostraram que a corrente e o comprimento do arco influenciam as características cinemáticas e dinâmicas das gotas em todas as condições estudadas, que o gás de proteção não exerce influência significativa nas características avaliadas, que a polaridade do eletrodo só afeta as características cinemáticas e dinâmicas no modo de transferência globular e que a quantidade de movimento efetiva das gotas influencia claramente a penetração do cordão de solda apenas quando associada à mudança no modo de transferência de globular para goticular. Adicionalmente, a corrente de soldagem afetou a penetração das soldas, mesmo utilizando-se aproximadamente o mesmo calor imposto, o comprimento do arco afetou a penetração das soldas de aço e alumínio e com diferentes gases de proteção, o gás de proteção não exerceu influência nos valores da penetração, mas alterou a forma do cordão e a polaridade não exerceu influência na penetração da solda, mas apenas na sua largura e reforço, sendo mais esbelto o cordão de solda em polaridade direta. / Doutor em Engenharia Mecânica
79

Síntese promovida por irradiação de micro-ondas de novos adutos de Morita-Baylis-Hillman hidrossolúveis com potencial atividade antiparasitária : um propostapara o uso do glicerol / Microwave-promoted synthesis of new water soluble Morita-Baylis- Hillman adducts with potential biological activity: a proposal for the use of glycerol.

Sousa, Suervy Canuto de Oliveira 30 March 2011 (has links)
Made available in DSpace on 2015-05-14T13:21:06Z (GMT). No. of bitstreams: 1 parte1.pdf: 1561006 bytes, checksum: 92830d9ef59f992edaa0a7616cdb4412 (MD5) Previous issue date: 2011-03-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This study was conducted in order to develop the synthesis of new Morita-Baylis-Hillman adducts of (MBHA) water soluble (29-34) with potential parasitic activity, using glycerol (1) as raw material. Two synthetic routes were carried out producing twelve new MBHA (23 - 34), six of which have hydrophilic characteristics 29-34 (main target of the work) and six more hydrophobic 23 28 (as synthesis intermediates), and these intermediaries are also important for comparative studies of structure and biological activity (SAR). Starting from glycerol (1), we synthesize the 2,2-dimethyl-1,3-dioxolan-4-yl)methyl acrylates (21, 94%) and from this, two synthetic routes were investigated to produce the 29- 34 adducts. On Route 1, the adducts 29-34 were produced in one-step (54 - 82%) from the Michael acceptor 2,3-dihydroxypropyl acrylate 22, which was prepared in 100% yield from 21. In route 2, MBHA intermediates 23 - 28 were prepared directly from 21 (90 - 100%) and these adducts were subsequently processed in adducts 29-34 (70 - 90%). In the synthesis of adduct 32 was observed the formation of the Michael addition product 47 and Indolizines unprecedented 48 as co-products of synthesis and characterized only by CGMS during the synthetic route 2. All syntheses in this work were developed in industry standards convenient. The activation reaction by microwave irradiation (MW) was widely used in most steps of this synthetic work, leading to high chemical yields and reduced reaction times. / Este trabalho foi realizado no intuito de desenvolver a síntese de novos adutos de Morita-Baylis-Hillman (AMBH) hidrossolúveis (29-34) com potenciais atividades antiparasitárias, usando o glicerol (1) como matéria-prima. Duas rotas sintéticas foram desenvolvidas conduzindo a doze AMBH inéditos (23 - 34), dos quais seis possuem as características hidrofílicas 29-34 (alvo principal do trabalho) e as outras seis mais hidrofóbicas 23 - 28 (como intermediários de síntese), sendo que estes intermediários são também importantes para estudos comparativos entre estrutura e atividades biológicas (SAR). Partindo do glicerol (1), sintetizamos o acrilato de 2,2-dimetil-1,3-dioxalila (21, 94%) e a partir deste, duas rotas sintéticas foram investigadas para os adutos-alvo 29- 34. Na rota 1, os adutos 29-34 foram produzidos em uma única etapa sintética (54 - 82%) a partir do aceptor de Michael acrilato de 2,3- dihidroxipropila 22, que foi preparado em 100% de rendimento a partir de 21. Na rota 2, os AMBH intermediários 23 28 foram preparados em 90 - 100% diretamente de 21 e estes adutos foram subseqüentemente transformados nos adutos 29-34 (70 - 90%). Na síntese do aduto 32 foi observado a formação do produto de adição de Michael 47 e da indolizina inédita 48 como co-produtos de síntese e caracterizados apenas por CGMS, durante a rota sintética 2. Todas as sínteses neste trabalho foram desenvolvidas em padrões convenientes a indústria. A ativação reacional por irradiação de microondas (MO) foi amplamente utilizada na maioria das etapas sintéticas deste trabalho, conduzindo aos altos rendimentos químicos e aos tempos reacionais reduzidos.
80

Study of metal transfer process in MIG / MAG through the fractal dimension of the signal voltage / Estudo da transferÃncia metÃlica no processo de soldagem MIG/MAG atravÃs da dimensÃo fractal do sinal de tensÃo

Josà Carlos de Souza Carneiro 04 April 2005 (has links)
The techniques for estimating the fractal dimension of signals have been widely applied in the description of many physical systems, from studies of atmospheric turbulence, EEG signals, water systems to studies on the behavior of fractal surfaces fractured by impact. The analysis of the fractal dimension of complex phenomena has become an important tool to quantify the degree of irregularity of artificial or natural phenomena. In this paper we investigate the fractal dimension of the signal voltage of the arc processode MIG / MAG welding. The estimation technique used for calculating the fractal dimension of the signals in the study was the method box couting. It was verified that rapid changes in the values ​​of fractal dimension were associated with the phenomenon of metal transfer. Shows the signal analyzed in the time domain, the photographic pictures of the metal transfer, obtained by the technique of shadowgrafia, and programs used to obtain the graphs, calculating the fractal dimension as well as statistics of the signals welding. In the literature review is made a presentation of the electric arc welding considering only its physical aspects. It appears the method used in calculating the fractal dimension of signals. Are also treated the electron emission mechanisms, the process of welding MIG / MAG, the phenomenon of metal transfer in MIG / MAG and the forces involved during metal transfer. / As tÃcnicas de estimativa da dimensÃo fractal de sinais tÃm sido amplamente aplicadas na descriÃÃo de inÃmeros sistemas fÃsicos, desde estudos sobre turbulÃncia atmosfÃrica, sinais de eletroencefalograma, sistemas hidrolÃgicos atà estudos sobre o comportamento fractal de superfÃcies fraturadas por impacto. A anÃlise da dimensÃo fractal de fenÃmenos complexos passou a ser uma ferramenta importante para quantificar o grau de irregularidade de fenÃmenos artificias ou naturais. Neste trabalho investigou-se a dimensÃo fractal dos sinais de tensÃo do arco voltaico do processode soldagem MIG/MAG. A tÃcnica de estimativa empregada para o cÃlculo da dimensÃo fractal no estudo dos sinais foi o mÃtodo box couting. PÃde-se verificar que variaÃÃes bruscas nos valores da dimensÃo fractal estavam associadas com o fenÃmeno da transferÃncia metÃlica. SÃo apresentados os sinais analisados, no domÃnio do tempo, os quadros fotogrÃficos da transferÃncia metÃlica, obtidos pela tÃcnica de shadowgrafia, e os programas utilizados para obtenÃÃo dos grÃficos, cÃlculo da dimensÃo fractal e tambÃm de dados estatÃsticos dos sinais de soldagem. Na revisÃo bibliogrÃfica à feita uma apresentaÃÃo do arco elÃtrico de soldagem considerando-se apenas seus aspectos fÃsicos. à apresentado o mÃtodo empregado no cÃlculo da dimensÃo fractal dos sinais. SÃo tratados tambÃm os mecanismos de emissÃo eletrÃnica, o processo de soldagem MIG/MAG, o fenÃmeno da transferÃncia metÃlica no processo MIG/MAG e as forÃas envolvidas durante a transferÃncia metÃlica.

Page generated in 0.0254 seconds