Cette étude porte sur la caractérisation des matériaux constituant le revêtement isolant de pipeline offshore ainsi que la soudure réalisée entre les deux polymères semi-cristallins du revêtement au niveau de la jonction entre deux tubes successifs.L’épaisseur très importante du revêtement induit, au cours du procédé de soudage, des vitesses hétérogènes de chauffe et de refroidissement des matériaux. Ces dernières ont été caractérisées grâce à une instrumentation du procédé en site industriel. Une modélisation numérique intégrant les phases successives du procédé est en bon accord avec les résultats expérimentaux. Cette modélisation permet de dresser une cartographie complète des champs de température dans l’ensemble du pipeline et plus précisément dans la zone de soudage.Cette étude nous a amené à réaliser une caractérisation des deux matériaux soudés au cours de leurs fusions et cristallisations qui représentent deux étapes cruciales lors du soudage. Une attention particulière a été portée au comportement rhéologique dans la zone de transition entre l’état fondu et l’état solide et inversement. Les données en refroidissement à différentes vitesses ont été corrélées avec le taux de transformation des matériaux.Les propriétés mécaniques des isolants ont été testées ainsi que celles des soudures en prélevant des éprouvettes sur les essais effectués en site industriel. Le peu de flexibilité du procédé industriel rend difficile une investigation de l’influence des paramètres de soudage. Une expérience « image », représentative des grandeurs industrielles, a donc été développée à l’échelle du laboratoire permettant de faire varier les paramètres de soudage. Il a été montré que le point de faiblesse de l’assemblage ne se situe pas au niveau de la soudure mais dans l’un des matériaux du revêtement. / This PhD focuses on the characterization of the materials of the insulating coating of offshore pipelines as well as the welding made between the two semi-crystalline polymers of the coating at the junction of two consecutives pipes.The important thickness of the coating induces heterogeneous heating and cooling rates during the welding process. Those rates have been characterized through the implementation of thermal sensors during the industrial process. A simulation model of the different steps of the welding process is consistent with the experimental results. This simulation gives access to the thermal fields in the entire pipe and especially in the welding zone.This study allows us to characterize the two welded materials during their melting and crystallization which represent the two crucial steps during the welding. A particular attention has been drawn to their rheological behavior in the transition zone from the molten to the solid state and vice versa. The cooling data at different rates have been correlated with the transformation fraction of the materials.The mechanical properties of the insulating materials have been tested especially in the welding zone via the industrial process. However, the imposing infrastructure of the industrial process does not allow the study of the influence of welding parameters. To do so, a “mirror” experiment, representative of the industrial one, has been developed at a laboratory scale. Both the welding made via the industrial process and the “mirror” experiment have shown that the weak point of the structure is not the welding itself but one of the materials of the coating.

Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2018-03-07T15:22:05Z No. of bitstreams: 1 2017 - Gabriela Vieira do Amaral.pdf: 1320069 bytes, checksum: bc0ab4f1fe7a912edee70092297020a1 (MD5) / Made available in DSpace on 2018-03-07T15:22:12Z (GMT). No. of bitstreams: 1 2017 - Gabriela Vieira do Amaral.pdf: 1320069 bytes, checksum: bc0ab4f1fe7a912edee70092297020a1 (MD5) Previous issue date: 2017-07-17 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Emerging supercritical carbon dioxide (SCCD) technology has been studied as a cold pasteurizing agent, however, few studies are available on its efficiency in dairy products. In this study, the effects of SCCD processing by different pressures 14, 16 and 18 MPa (35 ? 2 ?C / 10 min) on whey drink, whey drink and grape juice were investigated in comparison To conventional pasteurization (heat treatment at 72 ?C / 15 s). Physicochemical analyzes of pH, titratable acidity, total soluble solids, phenolic compounds, anthocyanins, antioxidant activity, angiotensin converting enzyme (ACE) inhibitory activity and volatile compounds were performed. The color, particle size, rheology, physical stability, as well as microbiological quality and sensory analysis of beverages were also smoothed. The results of this study evidenced the absence of differences between treatments in pH, titratable acidity, soluble solids, total anthocyanins and DPPH activity (p> 0.05). A direct relationship between SCCD pressure and ACE inhibitory activity was observed, with 34.63, 38.75 and 44.31% (14, 16 and 18 MPa, respectively). Few differences were found in the volatile compounds profile. The beverage processing by SCCD resulted in a product with lower particle diameter, lower consistency index and a reduction in pseudoplastic character compared to the beverage treated by the conventional process. No effect of high pressure CO2 on the sensorial attributes of the drink was observed for the studied levels. Consumers found no difference between CO2 treated beverages and heat-treated beverages. The results confirm the processing of SCCD as a promising technology for the non-thermal treatment of grape whey drink made available a health and wellness promoter beverage. Background: Non-thermal food processing is configured as an interesting alternative for the food industry due to the increased nutrient retention and minimal sensory changes in processed products. Scope and approach: The aim of this review is to address the potential of supercritical carbon dioxide technology, emphasizing milk and dairy processing, including the historical aspects, main advantages, microbial inactivation mechanisms, as well as effects in some quality parameters of dairy products. Key findings and conclusions: The use of supercritical carbon dioxide technology (SC-CO2) presents great potential application in dairy processing, since it is effective to reduce microbial load when compared to the pasteurization process, thus obtaining a product with greater shelf life and better organoleptic properties with minimal and sometimes positive changes in the intrinsic quality parameters The effect of supercritical carbon dioxide technology (SCCD, 140, 160, and 180 bar at 35 ? 2 ?C for 10 min) on whey-grape juice drink characteristics was investigated. Physicochemical characterization (pH, titratable acidity, total soluble solids), bioactive compounds ( phenolic compunds, anthocyanins , DPPH and ACE activity) and the volatile compounds were performed. Absence of differences were found among treatments for pH, titratable acidity, soluble solids, total anthocyanins and DPPH activity (p>0.05). A direct relationship between SCCD pressure and ACE inhibitory activity was observed, with 34.63, 38.75, and 44.31% (140, 160, and 180 bar, respectively). Regards the volatile compounds, it was noted few differences except by the presence of ketones. The findings confirm the SCCD processing as a potential promising technology to the conventional thermal treatment. The use of supercritical technology as a non-thermal pasteurization process of the whey-grape juice drink was investigated in this study. The effects of supercritical carbon dioxide at 14, 16, and 18 MPa (35 ? 2?C/10 min) on the physical and sensory properties of the beverage, when compared to conventional pasteurization (heat treatment at 72?C/15 s) were evaluated. High-pressure CO2 processing of whey-grape juice drink resulted in a product with lower particle diameter, lower consistency index, and a reduction in pseudoplastic character when compared to the beverage treated by the conventional process. No effect of high-pressure CO2 was observed on the sensory attributes of the beverage for the levels studied. Consumers did not find differences between the CO2-treated and heat-treated beverages. Our findings suggest the use of supercritical technology with carbon dioxide as an effective alternative for the production and availability of a health and wellness promoting beverage / A tecnologia emergente de di?xido de carbono supercr?tico (DCSC) vem sendo estudada como agente pasteuriza??o a frio, no entanto, s?o poucos os estudos dispon?veis a cerca da sua efici?ncia em derivados l?cteos. Neste estudo, foram investigados os efeitos do processamento do DCSC por diferentes press?es 14, 16 e 18 MPa (35 ? 2 ?C / 10 min) no whey drink de uva, bebida a base de soro de leite e suco de uva, em compara??o ? pasteuriza??o convencional (tratamento t?rmico a 72 ?C / 15 s). Foram realizadas an?lises f?sico-quimicas de pH, acidez titul?vel, s?lidos sol?veis totais, compostos fen?licos, antocianinas, atividade antioxidante, atividade inibidora da enzima conversora de angiotensina (ECA) e compostos vol?teis. Tamb?m foramam alisados a cor, o tamanho de part?cula, reologia, estabilidade f?sica, assim como a qualidade microbiol?gica e analise sensorial das bebidas. Os resultados deste estudo evidenciaram a aus?ncia de diferen?as entre os tratamentos nas an?lises de pH, acidez titul?vel, s?lidos sol?veis, antocianinas totais e atividade de DPPH (p> 0,05). Foi observada uma rela??o direta entre press?o DCSC e atividade inibit?ria ACE, com 34,63, 38,75 e 44,31% (14, 16 e 18 MPa, respectivamente). Poucas diferen?as foram encontratdas no perfil dos compostos vol?teis. O processamento das bebidas por DCSC resultou em um produto com menor di?metro de part?cula, menor ?ndice de consist?ncia e uma redu??o no car?ter pseudopl?stico em compara??o com a bebida tratada pelo processo convencional. N?o foi observado efeito de CO2 de alta press?o nos atributos sensoriais da bebida para os n?veis estudados. Os consumidores n?o encontraram diferen?as entre as bebidas tratadas com CO2 e as bebidas tratadas termicamente. Os resultados confirmam o processamento do DCSC como uma tecnologia promissora para o tratamento n?o t?rmico de whey drink de uva disponibilizado uma bebida promotora de sa?de e bem-estar Antecedentes: Os processamentos de alimentos n?o t?rmicos s?o configurados como uma alternativa interessante para a ind?stria de alimentos devido ao aumento da reten??o de nutrientes e mudan?as sensoriais m?nimas nos produtos processados. ?mbito e abordagem: o objetivo desta revis?o ? abordar o potencial da tecnologia de di?xido de carbono supercr?tico, enfatizando o processamento de leite e l?cteos, incluindo os aspectos hist?ricos, as principais vantagens, os mecanismos de inativa??o microbiana, bem como os efeitos em alguns par?metros de qualidade dos produtos l?cteos. Principais conclus?es e conclus?es: o uso de tecnologia supercr?tica de di?xido de carbono (SC-CO2) apresenta grande potencial de aplica??o no processamento de l?cteos, uma vez que ? efetivo reduzir a carga microbiana quando comparado ao processo de pasteuriza??o, obtendo-se assim um produto com maior prateleira e melhores propriedades sensoriais com mudan?as m?nimas e ?s vezes positivas nos par?metros de qualidade intr?nseca. O efeito da tecnologia de di?xido de carbono supercr?tico (SCCD, 140, 160 e 180 bar a 35 ? 2 ?C durante 10 min) em caracter?sticas de bebidas de suco de uva foi investigado. Caracteriza??o f?sico-qu?mica (pH, acidez titul?vel, s?lidos sol?veis totais), compostos bioativos (compostos fen?licos, antocianinas, DPPH e atividade ACE) e os compostos vol?teis foram realizados. A aus?ncia de diferen?as foi encontrada entre tratamentos para pH, acidez titul?vel, s?lidos sol?veis, antocianinas totais e atividade de DPPH (p> 0,05). Foi observada uma rela??o direta entre press?o SCCD e atividade inibit?ria ACE, com 34,63, 38,75 e 44,31% (140, 160 e 180 bar, respectivamente). Atende aos compostos vol?teis, observou-se poucas diferen?as, exceto pela presen?a de cetonas. Os resultados confirmam o processamento do SCCD como uma potencial tecnologia promissora para o tratamento t?rmico convencional O uso da tecnologia supercr?tica como processo de pasteuriza??o a frio da bebida de suco de uva e soro de uva foi investigado neste estudo. Os efeitos do di?xido de carbono supercr?tico em 14, 16 e 18 MPa (35 ? 2 ?C / 10 min) nas propriedades f?sicas e sensoriais da bebida, quando comparados ? pasteuriza??o convencional (tratamento t?rmico a 72 ?C / 15 s) Foram avaliados. O processamento de CO2 de alta press?o da bebida de suco de soro de soro de leite resultou em um produto com menor di?metro de part?cula, menor ?ndice de consist?ncia e uma redu??o no car?ter pseudopl?stico em compara??o com a bebida tratada pelo processo convencional. N?o foi observado efeito de CO2 de alta press?o nos atributos sensoriais da bebida para os n?veis estudados. Os consumidores n?o encontraram diferen?as entre as bebidas tratadas com CO2 e as bebidas tratadas termicamente. Nossas descobertas sugerem o uso da tecnologia supercr?tica com di?xido de carbono como uma alternativa efetiva para a produ??o e disponibilidade de uma bebida promotora de sa?de e bem-estar