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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.
191

FUI Ecoating. Comprehension of the Scale Formation Mechanism during the Suspension Polymerization of Vinyl Chloride Monomer and Development of a Durable Protective Polymer Coating / FUI Ecoating. Compréhension du Mécanisme d'Encroûtement lors de la Polymérisation en Suspension du Chlorure de Vinyle et Développement d'un revêtement Polymère Durable

Huser, Julien 01 October 2013 (has links)
La production de poly(chlorure de vinyle) (PVC) sous forme de suspension chez INEOS ChlorVinyls est réalisée en réacteur fermé agité, dont les parois sont en émail ou en acier inoxydable. Il se forme en cours de polymérisation un dépôt de PVC (croûte) sur les parois du réacteur qui génère de nombreux inconvénients. Afin de limiter cet encroûtement, INEOS ChlorVinyls et l’ensemble des producteurs de PVC appliquent à chaque batch (par exemple pour INEOS ChlorVinyls 50 fois par jour pour ses 22 réacteurs) un revêtement organique. L’application systématique du revêtement et la formation de croûtes ont des conséquences économiques non négligeables (arrêts de production, coût de main d’œuvre et matière, coût de traitement des déchets, qualité du PVC contaminé par le revêtement…).La compréhension du phénomène d’encroûtement en vue de développer un revêtement permanent devient donc nécessaire pour améliorer la qualité des produits, diminuer les coûts et dégager un avantage concurrentiel favorable à INEOS vis-à-vis de ses concurrents. Le sujet de thèse a été divisé en deux parties bien distinctes avec premièrement l’étude du mécanisme d’encroûtement et la mise en place d’un scénario permettant d’expliquer de manière physique et chimique la formation de la croûte sur les parois du réacteur. Une seconde partie a été dédiée au développement d’un revêtement polymère avec la sélection d’un système résistant au milieu réactionnel de polymérisation en suspension du chlorure de vinyle puis à l’optimisation de l’adhésion du revêtement polymère sur acier inoxydable afin d’obtenir des performances maximales et durables. / The suspension synthesis of PolyVinyl Chloride (S-PVC) at the INEOS ChlorVinyls facility in Mazingarbe (FRANCE) is realized thanks to a closed-reactor technology with reactor walls made of stainless steel or enamel. One of the major problems during the production of PVC by suspension polymerization is the formation of a deposit (called crust or scale) on the reactor walls. The formation of scale leads to numerous sorts of drawbacks like a decrease of the reactors’ productivity, the need to clean the reactors after each batch, the exposure of the operators to VinylChloride Monomer (VCM) which is classified CMR, some quality issues… At the moment, a coating is applied before each batch (50 times per day for the 22 reactors at Mazingarbe) in order to lower the amount of scale formed during the S-PVC batch. The application of the coating added to the formation of scale leads to important extra costs. The comprehension of the scale formation mechanism with the aim of then developing a durable protective coating becomes a priority in order to increase the final product quality, lower the costs and gain a competitive advantage for INEOS ChlorVinyls. The Ph.D. subject was divided into two parts with the first year dedicated to the comprehension of the scale formation mechanism and the establishment of a complete scenario explaining the formation of scale from a chemical and physical point of view. The second part of this project was dedicated to the development of a polymer coating with the selection of an adapted polymer candidate and then the optimization of its adhesion onto stainless steel in order to obtain the optimal performances and the durability of the coating.
192

Study Of Shear In Dry Granular Flows Through Vertical Channels

Moka, Sudheshna 01 1900 (has links) (PDF)
No description available.
193

Poly (butylene succinate) and poly (butylene adipate) : quantitative determination of degradation products and application as PVC plasticizers

Lindström, Annika January 2005 (has links)
<p>A solid phase extraction (SPE) method was developed for simultaneous extraction of dicarboxylic acids and diols formed during hydrolysis of poly(butylene succinate), PBS, and poly(butylene adipate), PBA. The developed SPE method and subsequent GC-MS analysis were used to extract, identify and quantify low molecular weight products migrating from linear and branched poly(butylene adipate) (PBA) and poly(butylene succinate) (PBS) during aging in aqueous media. The combination of SPE and GC-MS proved to be a sensitive tool, able to detect small differences in the degradation rate during early stages of hydrolysis before any significant differences were observed by weight loss and molecular weight measurements. The detected low molecular weight products included monomers i.e. adipic acid and 1,4-butanediol for the PBA polymers and succinic acid and 1,4-butanediol for PBS. Several dimers and trimers i.e. hydroxybutyl adipate, hydroxybutyl succinate, di(hydroxybutyl) adipate, di(hydroxybutyl) succinate and hydroxybutyl disuccinate were also detected. Best extraction efficiency for 1,4-butanediol and succinic acid was achieved with a hydroxylated polystyrene-divinylbenzene resin as solid phase. Linear range for the extracted analytes was 1-500 ng/ml for adipic acid and 2-500 ng/ml for 1,4-butanediol and succinic acid. Detection and quantification limits for all analytes were between 1-2 ng/ml (S/N=3) and 2-7 ng/ml (S/N=10) respectively. Relative standard deviations were between 3 % and 7 %. Comparison of measured weight loss and the amount of monomeric products showed that weight loss during early stages of hydrolysis was mainly caused by the release of water-soluble oligomers that on prolonged ageing were further hydrolyzed to monomeric species. Significant differences in degradation rate could be assigned to degree of branching, molecular weight, aging temperature and degradation medium.</p><p>Linear and branched PBA was mixed with PVC in solution cast films to study the effects of molecular weight and branching on plasticizer efficiency. Used as polymeric plasticizer, PBA formed a semi-miscible two-phase system with PVC where the amorphous part exhibited one single glass transition temperature and the degree of polyester crystallinity was dependent on molecular weight, degree of branching and blend composition. Plasticizing efficiency was favored by higher degree of branching and a 40 weight-percent polyester composition.</p>
194

Etude du microbiote susceptible de persister sur les surfaces d'un atelier de la filière viande bovine

Khamisse, Elissa 06 April 2012 (has links) (PDF)
Ce travail de thèse concerne l'étude de l'écologie microbienne d'un atelier de découpe de viande bovine, dans le but de mieux comprendre la persistance bactérienne, c'est-à-dire, la présence répétée d'un même clone bactérien pendant une longue période malgré l'application bien conduite et régulière du nettoyage et de la désinfection (N-D). Des prélèvements par " chiffonnages " multiples de surfaces d'équipements ont été réalisés lors de trois campagnes de prélèvement espacées les unes des autres d'au moins six mois. Les prélèvements ont été réalisés sur un tapis convoyeur en polychlorure de vinyle (PVC) et sur des machines éplucheuses en acier inoxydable avant et après N-D. Nous avons quantifié les cellules totales (les cellules vivantes et les cellules mortes) par PCR quantitative en temps réel (qPCR), les cellules viables par EMA-qPCR, et les UFC (provenant de cellules cultivables) par dénombrement après incubation à 25°C sur gélose tryptone soja. Les résultats montrent qu'avant N-D, les cellules totales (en moyenne 5,6 - exprimé en log10 cellules/cm2 - sur PVC et 4,7 sur acier inoxydable) sont plus nombreuses que les cellules viables (4,5 sur PVC et 4,4 sur acier inoxydable) lesquelles sont plus nombreuses que les UFC (3,8 sur PVC et 2,9 sur acier inoxydable). Le N-D entraîne moins d'une réduction décimale (RD) des populations à l'exception des UFC sur acier inoxydable qui subissent 1,5 RD en moyenne. Ce dernier chiffre s'explique par des forces d'adhésion faibles. L'étude de la diversité des bactéries cultivables montre que sur un total de 51 genres identifiés, 13 seulement sont retrouvés lors des trois campagnes de prélèvements. Les isolats de ces 13 genres représentent 75, 72 et 62% des isolats des campagnes1, 2 et 3 respectivement. Parmi ces isolats, les plus fréquents sont (par ordre décroissant du nombre d'isolats) : Pseudomonas, Staphylococcus, Microbacterium, Acinetobacter, Chryseobacterium, Psychrobacter et Kocuria. Le génotypage d'isolats de 3 genres majoritaires (Staphylococcus, Pseudomonas et Acinetobacter) montre qu'une seule souche, Staphylococcus equorum, est sans aucun doute persistante. L'ensemble de ces observations montrent que l'écosystème varie d'une campagne à une autre. Ces modifications de la diversité bactérienne reflèteraient les modifications de flores des viandes traitées dans l'atelier, qui ont des origines multiples. En outre, il apparaît que, contrairement à ce qui est généralement admis, les bactéries à coloration de Gram négative cultivables sont plus facilement inactivées par le N-D que les bactéries à coloration de Gram positive. L'étude de l'écosystème par PCR-DGGE a permis d'identifier sept genres bactériens et montre que les espèces dominantes sont toutes sous forme vivante, autrement dit, aucune des espèces dominantes n'a été détectée uniquement sous forme de cellules mortes. Sur les sept genres identifiés six sont des Gram - dont majoritairement les genres Acinetobacter, Pseudomonas et Psychrobacter. Cette dominance montre que le N-D permet une forte perte de cultivabilité des bactéries Gram - mais qu'une grande partie n'est pas détachée. La dominance des bactéries Gram - observée par PCR-DGGE masque les staphylocoques qui ne sont pas détectés alors qu'ils sont majoritaires parmi la flore cultivable. Seul un genre bactérien, Propionibacterium, est identifié par PCR-DGGE uniquement mais il n'est trouvé qu'à une seule campagne et uniquement sur l'acier inoxydable avant N-D. En conclusion, l'avancée majeure de ce travail est la mise en évidence qu'une proportion importante de bactéries survit après les opérations très poussées de N-D mais pour une période transitoire.
195

Contaminantes orgânicos em monômero cloreto de vinila (MVC): desenvolvimento de método para identificação por TD-GC-MS e análise por PCA aplicada a amostras de diferentes pontos de um processo industrial

Santos, Fábio Neves dos 02 1900 (has links)
Submitted by Ana Hilda Fonseca (anahilda@ufba.br) on 2014-09-17T15:13:51Z No. of bitstreams: 1 Fabio Neves Dissertação.pdf: 1617814 bytes, checksum: 880cf6fc37213ab6dcd60cf882b1ffb3 (MD5) / Approved for entry into archive by Fatima Cleômenis Botelho Maria (botelho@ufba.br) on 2014-09-19T12:31:43Z (GMT) No. of bitstreams: 1 Fabio Neves Dissertação.pdf: 1617814 bytes, checksum: 880cf6fc37213ab6dcd60cf882b1ffb3 (MD5) / Made available in DSpace on 2014-09-19T12:31:43Z (GMT). No. of bitstreams: 1 Fabio Neves Dissertação.pdf: 1617814 bytes, checksum: 880cf6fc37213ab6dcd60cf882b1ffb3 (MD5) / O monômero cloreto de vinila (MVC) é a principal matéria-prima utilizada na produção do Policloreto de vinila (PVC). Sendo assim, o controle da pureza do MVC é fundamental para o controle da reação de polimerização, bem como para as propriedades do PVC, visto que alguns contaminantes orgânicos reagem como co-monômeros. Portanto, faz-se necessário o desenvolvimento de metodologias para identificação das substâncias presentes como contaminantes do MVC. Neste trabalho, foram desenvolvidos métodos de identificação dos contaminantes, baseados na sua pré-concentração por adsorção em Tenax-TA e Tenax- TA/Carboxen1000/CarbosieveSIII, seguidos de dessorção térmica e análise por cromatografia gasosa acoplada à espectrometria de massas (TD-GC-MS). A otimização desses métodos foi realizada utilizando-se planejamento fatorial de experimentos completo e fracionário. Os métodos otimizados foram utilizados na identificação dos contaminantes do MVC nas etapas do processo de obtenção, armazenamento e recuperação do monômero, correspondendo a quatro pontos distintos de coleta das amostras. Foram identificadas ao todo dezenove substâncias dentre as quais hidrocarbonetos alifáticos e aromáticos, organoclorados, alcoóis, fenóis e fenonas. Destas, doze estavam presentes no MVC virgem, treze no MVC da esfera de armazenamento, doze no MVC da entrada dos reatores de polimerização e dezesseis no MVC recuperado. Os contaminantes presentes com as maiores concentrações relativas nos diferentes pontos foram estireno, aromático C6, tolueno, naftaleno, 1-octanol e 1,3- butadieno. Destes, estireno e 1,3-butadieno tem sido relatados na literatura como sendo fortes inibidores de polimerização para o MVC. Através da análise de componentes principais foi possível comprovar que há diferenças nas características do MVC, a depender do ponto do processo de onde ele é captado. Além disso, foi possível classificar as amostras de MVC, provenientes de diferentes pontos do processo, em três agrupamentos distintos, bem como identificar em cada agrupamento os principais contaminantes responsáveis pelas diferenciações. Considerando que o controle da pureza do monômero é fundamental para a qualidade do PVC, estes resultados demonstram a importância de realizar experimentos em escala de laboratório com o MVC proveniente de cada ponto, a fim de verificar a influência dos seus contaminantes característicos sobre as propriedades do PVC produzido. Com essas informações será possível buscar estratégias para a eliminação ou redução dos principais contaminantes responsáveis pelas alterações nas propriedades do produto final. / The Vinyl Chloride Monomer (MVC) is the main raw material used in the production of Poly (Vinyl Chloride) (PVC). Thus, the control of MVC purity is essential to control polymerization reaction, as well as the properties of PVC, since some organic contaminants react as co-monomers. Therefore, it is necessary to develop methodologies for the identification of substances as contaminants MVC. In this work, we developed methods for identifying contaminants, based on your pre- concentration by adsorption on Tenax-TA and Tenax- TA/Carboxen1000/CarbosieveSIII, followed by thermal desorption and analysis by Gas Chromatography-Mass Spectrometry (TD-GC-MS). The optimization of these methods was performed using full factorial design of experiments and fractional. The optimized methods were used in the identification of contaminants in the MVC stages of acquisition, storage and retrieval of the monomer, corresponding to four distinct points of sample collection. We identified a total of nineteen substances among which aliphatic and aromatic hydrocarbons, organochlorine, alcohols, phenols and fenonas. Of these, twelve were present in virgin MVC, MVC thirteen in the storage sphere, twelve in MVC input of polymerization reactors and sixteen in MVC recovered. Contaminants with higher relative concentrations in different points were styrene, benzene, toluene, naphthalene, 1-octanol and 1,3-butadiene. Of these, 1,3-butadiene and styrene have been reported in the literature as strong polymerization inhibitors for MVC. Through Principal Component Analysis was possible to prove that there are differences in the characteristics of the MVC, depending on the point in the process where it is captured. Moreover, it was possible to classify the samples MVC from different points of the process in three distinct clusters and identify each cluster major contaminants responsible for differentiation. Whereas the control of the purity of the monomer is critical to the quality of the PVC, these results demonstrate the importance of conducting experiments on a laboratory scale with the MVC from each point, in order to check the influence of its contaminants on the characteristic properties of PVC produced. With this information you can find strategies for elimination or reduction of major pollutants responsible for changes in the properties of the final product.
196

Modifica??o do eletrodo AWS E7018 com adi??o de filmes finos externos de PVC e Al, para soldagem de a?o C-Mn

Ramos, Moacir Bispo 07 December 2015 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-07-20T22:04:59Z No. of bitstreams: 1 MoacirBispoRamos_TESE.pdf: 16232608 bytes, checksum: 452eef16e8cb0bb6456bb9da73f46508 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-07-21T21:33:32Z (GMT) No. of bitstreams: 1 MoacirBispoRamos_TESE.pdf: 16232608 bytes, checksum: 452eef16e8cb0bb6456bb9da73f46508 (MD5) / Made available in DSpace on 2016-07-21T21:33:32Z (GMT). No. of bitstreams: 1 MoacirBispoRamos_TESE.pdf: 16232608 bytes, checksum: 452eef16e8cb0bb6456bb9da73f46508 (MD5) Previous issue date: 2015-12-07 / O presente trabalho prop?e a modifica??o do revestimento de eletrodos de baixo hidrog?nio, propiciando uma alternativa para execu??o de soldagem com o AWS E-7018 sem precisar resseca-los, reduzindo por conseguinte os custos financeiros e o tempo de fabrica??o de soldas estruturais de alta resist?ncia. As soldas deste estudo foram produzidas a partir de eletrodos com revestimento b?sico (higrosc?picos) - processo manual - pintados com tinta spray de alum?nio para altas temperaturas ou revestidos com filmes finos de PVC e de papel alum?nio (99,9%), comumente utilizados para prote??o de alimentos. A premissa b?sica ?, que estabelecendo uma barreira entre a atmosfera e o revestimento do eletrodo, poder-se-? diminuir os efeitos da alta higroscopicidade apresentada pelo revestimento, minimizando assim, a principal fonte de fornecimento de hidrog?nio ? po?a de fus?o durante a soldagem, tamb?m ? esperado, que a adi??o de novos materiais no revestimento ? po?a de fus?o, provoque altera??es metal?rgicas no metal depositado e consequentemente altera??es nas propriedades mec?nicas. Mensurar o hidrog?nio dissolvido no metal depositado ap?s soldado com os eletrodos modificados, avaliar a influencia dessas modifica??es nas microestruturas produzidas, nas propriedades mec?nicas da solda resultante e comparar esses resultados obtidos com procedimentos de soldagem padr?o normatizados e com os novos eletrodos imperme?veis recentemente desenvolvidos, balizou o estudo. Os resultados obtidos, na maioria das amostras soldadas com eletrodos modificados, apresentaram aumento significativo da resist?ncia mec?nica e de tenacidade, justificados pelo aumento percentual de ferrita acicular no metal depositado, sem, contudo, eleva??o significativa da dureza, quando comparados com a soldagem com eletrodo AWS E-7018 da forma tradicional. O hidrog?nio difus?vel nos eletrodos modificados manteve-se dentro do estabelecido pelos c?digos internacionais. / This paper suggests modifications in coating of electrodes providing an alternative for execution of welding with low hydrogen electrode AWS E7018 without having to dry it, reducing thus the cost and time of manufacturing of high resistance welds. The welds in this research were developed with basic coated electrodes (hygroscopic) ? SMAW process ? externally painted with aluminum spray paint for high temperatures or wrapped with thin plastic films (PVC) and aluminum foil films used commonly for food protection. The basic premise is that establishing a barrier between the atmosphere and the electrode coating could reduce the effects of high hygroscopicity presented by coatings of low hydrogen, minimizing this way the main source of supply of hydrogen to the fusion pool during welding. It is also expected that the addition of new materials from the electrode coating to the fusion pool would induce metallurgical changes in the deposited metal and, as a consequence, modifications in its mechanical properties. This research dealt with measuring the dissolved hydrogen in the deposited metal after welding with modified electrodes, evaluating the influence of these changes in the produced microstructures and in the mechanical properties of the resulting weld, and comparing the obtained results with the standard welding procedures and with the recently developed waterproof electrodes. The results obtained in most samples welded with modified electrodes showed increased mechanical resistance and increased tenacity due to the increased percentage of acicular ferrite in metal deposited without significant elevation of hardness, when compared with the traditional welding with AWS E7018 electrode and with ELBR?S BRH4R waterproof electrode. The diffusing hydrogen measured in the modified electrodes was kept inside the parameters defined by international codes.
197

Influ?ncia do aporte t?rmico e da adi??o de filmes de alum?nio e PVC em eletrodos revestidos E7018

Souza, C?cero Leonardo Pereira de 10 March 2017 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2018-02-15T11:17:50Z No. of bitstreams: 1 CiceroLeonardoPereiraDeSouza_DISSERT.pdf: 12093980 bytes, checksum: 07b7fe22cb40d5bdd02b643fb06ab78a (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-02-16T11:10:32Z (GMT) No. of bitstreams: 1 CiceroLeonardoPereiraDeSouza_DISSERT.pdf: 12093980 bytes, checksum: 07b7fe22cb40d5bdd02b643fb06ab78a (MD5) / Made available in DSpace on 2018-02-16T11:10:32Z (GMT). No. of bitstreams: 1 CiceroLeonardoPereiraDeSouza_DISSERT.pdf: 12093980 bytes, checksum: 07b7fe22cb40d5bdd02b643fb06ab78a (MD5) Previous issue date: 2017-03-10 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / A soldagem a arco el?trico por eletrodo revestido (SMAW) ? uma das mais antigas t?cnicas de soldagem e a primeira a ser utilizada industrialmente em grande escala. Durante o s?culo XX a soldagem SMAW foi a mais usada como t?cnica de uni?o permanente de metais, sendo at? hoje, mesmo com coexist?ncia de diversas outras t?cnicas, uma das que possuem maior utiliza??o no mercado brasileiro. Nesse tipo de soldagem uma das maiores preocupa??es ? o cuidado no armazenamento do eletrodo, pois o mesmo n?o pode ficar exposto a atmosfera ambiente, j? que absorveria umidade, que ? danoso para a qualidade da solda. A umidade introduz na zona fundida o hidrog?nio que pode levar ao surgimento de trincas a frio. A solu??o normalmente usada ? a da ressecagem em temperaturas at? 450? C, acompanhada de armazenamento em estufas, pr?tica que gera custos adicionais para um projeto de fabrica??o. Nesse contexto o presente trabalho teve a inten??o de caracterizar a zona fundida de soldas feitas com eletrodos revestidos E7018 encobertos com filmes de alum?nio e PVC, aplicados com o intuito de resguarda-los contra a umidade ambiente, diminuindo custos e tempo com secagem, tamb?m variando o valor de aporte t?rmico utilizado durante a soldagem. Essa atual investiga??o d? continuidade ? pesquisa recente sobre a influ?ncia de tais filmes protetores na composi??o e, em especial, na microestrutura do metal de solda depositado, onde a quantifica??o dos constituintes e caracteriza??o microestrutural ocorreu atrav?s de um software para avalia??o de imagens. No presente caso, com a utiliza??o de um microsc?pio com emiss?o de campo, MEV-FEG, foram obtidas imagens com elevado contraste, que permitiram um levantamento detalhado dos tipos de constituintes presentes, assim como uma an?lise mais precisa de sua morfologia. Em particular foi poss?vel avaliar quantitativamente o efeito dos filmes protetores no tamanho de gr?o e na raz?o de aspecto do microconstituinte AF (ferrita acicular). Com base numa revis?o da literatura ? apresentada uma an?lise cr?tica acerca dos par?metros que tiveram maior relev?ncia na forma??o da microestrutura final e nas propriedades mec?nicas obtidas. Os resultados conduziram a constata??o de que para maiores valores de aporte t?rmico a microestrutura, em especial a ferrita acicular, tende a ser mais grosseira. Com a utiliza??o dos revestimentos de PVC e tinta de alum?nio obteve-se uma leve diminui??o nessa granulometria, j? que a microestrutura apresentou-se mais refinada do que com os eletrodos de refer?ncia (E7018 puro e BRH4R). / The shield metal arc welding (SMAW) is one of the oldest welding processes and the first one to be used in large industrial scale. During the XX century the SMAW was the most applied process for metal joining, remaining until nowadays as one of the most used in the Brazilian market. In this kind of welding one of the biggest problems is to avoid the hydrogen induced cold cracking, what imposes rigid requirements in the storing of the weld consumables. In order to avoid the humidity absorption, the consumables must be dried out in special ovens at temperatures in the order of 450 C, what implies in additional and higher manufacturing costs. In this context a recent research suggested modifications in coating of electrodes providing an alternative for execution of welding with low hydrogen electrode AWS E7018 without having to dry it, The welds were developed with basic coated electrodes (hygroscopic) externally painted with aluminum spray paint for high temperatures or wrapped with thin plastic films (PVC) and aluminum foil films. The induced metallurgical changes in the deposited metal, associated with the addition of new materials to the electrode coating, were investigated, wereby the microconstituents in the fusion zone were quantified using a software for image analysis. In the actual work, with the use of a field emission microscope, MEV-FEG, high contrast images could be obtained, this allowed a detailed characterization of the various microconstituents and a more precise description of their morphology. In special it was possible to evaluate the influence of the protective films in the grain size and aspect ratio of the microconstituent AF (acicular ferrite). On base of a literature review a critical analysis is presented, that embraces the effect of the more relevant parameters on the final microstructure and resulting mechanical properties. The results showed that for higher values of heat input the microstructure, especially the acicular ferrite, tends to be coarser. With the use of PVC coatings and aluminum paint, a slight reduction was achieved in this granulometry, since the microstructure was more refined than with reference electrodes (E7018 pure and BRH4R).
198

[en] ANALYSIS OF CONCRETE - PVC CONSTRUCTION SYSTEM CONCERNING THE LOGISTICS TRANSPORTATION TO THE BUILDING OF THE SCIENTIFIC STATION OF TRINDADE ISLAND (ECIT) / [pt] ANÁLISE DO SISTEMA CONSTRUTIVO CONCRETO - PVC EM RELAÇÃO À LOGÍSTICA DE TRANSPORTE PARA CONSTRUÇÃO DA ESTAÇÃO CIENTÍFICA DA ILHA DA TRINDADE (ECIT)

MAURO CESAR DELARUE DOS SANTOS 29 February 2016 (has links)
[pt] Construir em ilhas oceânicas ou locais de difícil acesso exige o prévio conhecimento das restrições impostas pelas dificuldades de transporte. Nesta dissertação o objetivo é reconhecer qual é o sistema construtivo mais adequado à logística de transporte de materiais para produção de edificações na Ilha da Trindade. Com esse propósito é apresentada uma proposta de investigação e análise da transportabilidade dos materiais peculiares aos sistemas construtivos já empregados em construções na Ilha da Trindade. O enfoque á a análise do sistema construtivo concreto – PVC empregado na produção da Estação Científica da Ilha da Trindade (ECIT), construída no ano de 2011 na Ilha da Trindade, Vitória – ES, destacando suas características ecológicas e de sustentabilidade aliadas à aplicação do PVC, nunca antes utilizado em construções de edificações em ilhas oceânicas brasileiras. A metodologia proposta consiste em atribuir conceito e valores aos resultados das análises qualitativas e quantitativas das características (peso e volume), propriedades executivas (pré-fabricação, montagem e desmontagem), necessidades de embalagens (resistência e mobilidade) e aspectos de sustentabilidade aplicados na transportação (prazos e consumos) dos materiais peculiares aos sistemas construtivos investigados. Os resultados das análises e avaliação final mostram que o sistema construtivo constituído de painéis de PVC é o mais adequado à logística de transporte de materiais para produção de edificações na Ilha da Trindade. Dentre outros fatos tem-se a proposta de metodologia apresentada, que pode servir de consulta a profissionais e/ou empresas do ramo, de forma a contribuir para futuras investigações e pesquisas relacionadas ao tema abordado, ou a permitir dar origem a novos questionamentos. / [en] To verify what construction system is more suitable to the complex transportation logistics of Trindade Island, the transportability of materials and construction systems already used in the production of buildings in the Oceanographic Station of the Trindade Island (POIT) was analysed by means of transportation made available by the Brazilian Navy, considering as a case study the construction of the Station Scientific of Trindade Island (ECIT), built in the period between the years 2009 and 2011. For this purpose, the technical aspects analyzed were the characteristics (weights and measures), executive properties (prefabrication possibilities, assembly and disassembly), the need of packages (resistance and mobility), and sustainability (impact, time spent and consumption in transport) of the main materials of construction systems using ceramic brick masonry, concrete blocks, wood paneling and forms of PVC filled with concrete (concrete-PVC).
199

Environmental Impacts of Fiber Composite Materials : Study on Life Cycle Assessment of Materials used forShip Superstructure

Umair, Shakila January 2006 (has links)
This thesis was conducted to investigate the impacts of fiber composites on theenvironment. Composition, properties and application of fiber compositeswere also studied. On the basis of its application, taking into account previousstudies information was gathered related to impacts of these fiber composites.In order to study impacts of fiber composites in marine application a detailstudy was conducted where using the LCA method and Sima Pro softwarethree ship superstructures of the ship Stena Hollandica were compared. Thesewere steel superstructure, balsawood core superstructure and PVC foamsuperstructure. The results showed that over the lifecycle the impacts of PVCand balsawood superstructure were almost the same and were better than thesteel superstructure. The main contribution of impacts over the lifetime wasdue to the fuel consumed. When only the superstructure was consideredseparately from the life cycle the best choice was balsawood and the PVC foamsuperstructure had the most impacts. Overall it was found that balsawoodcould be considered as the best alternative as a material for the construction ofthis ship superstructure.
200

Developing Constitutive Equations for Polymer Foams Under Cyclic Loading

Chen, Linling 11 December 2012 (has links)
No description available.

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