En tant que polymère de grande diffusion, les applications du polypropylène isotactique (PP) sont limitées par sa faible resistance au choc. D'après la relation structure - propriétés, sa résistance au choc peut être améliorée en contrôlant sa structure. Dans ces travaux, différents types d'agents nucléants ont été utilsés pour promouvoir la formation des cristaux de type bêta et de mélanges de deux PP de masses molaires différentes. Les propriétés mécaniques, le comportement à la rupture, et la morphologie cristalline ont été étudiés. Les influences du type et de la teneur en peroxyde et agent nucléant sur la morphologie cristalline et les propriétés mécaniques ont aussi été explorées. Un agent nucléant suporté sur des nanotubes de carbone multi-parois (MWCNT) a été utilisé pour modifier la structure cristalline du PP, ce qui a permis d'augumeter sa résistance au choc 7 fois comparée à celle du PP vierge et 3 fois comparée à celle du PP cristallisé en phase bêta. Cette importante augmentation en resistance au choc peut être attribuée à la formation des trans-cristaux de type bêta qui est favorisée par l?agent nucléant supporté sur les MWCNT / As a commodity polymer, the applications of isotactic polypropylene (PP) are limited by its low impact strength. Based on the structure-property relationship, its impact strength could be improved by controlling its structure. In this study, different kinds of nucleating agents were used to promote the formation of beta crystals of PP as well as mixtures of two PPs of different molar masses. The mechanical properties, fracture behaviour, and crystalline morphology were investigated. The effects of the type and content of the peroxide and nucleating agent on the crystalline structure and mechanical properties of the PP were also explored. A multi-walled carbon nanotude (MWCNT) supported nucleating agent was introduced to modify the crystalline structure of PP and the impact strength of the resulting PP was 7 times that of the pure PP and more than 3 times that of beta nucleated PP. The large increase in the impact strength was attributed to the formation of beta transcrystalline morphology which was promoted by the MWCT supported nucleating agent

Neste trabalho foram estudadas as microestruturas, dureza, e resistência ao impacto em aço alta resistência e baixa liga (ARBL) na ZAC. O processo de soldagem foi por arco submerso, utilizando corrente de 600A, tensão de 25V, velocidade de soldagem de 25,5; 24; 20,94; e 19,5 cm/min. Utilizou-se chapa de aço USI-SAC-50. Os quatro aportes de calor produzidos 3,53; 3,75; 4,24; 4,61 kJ/mm, permitiram variações microestruturais na região de granulação grosseira da ZAC, promovendo variações nas medidas de durezas e nos resultados do ensaio de impacto medido à -25ºC e -10ºC. Quando realizado o tratamento térmico de alívio de tensões a 580ºC por 1 hora, as morfologias das microestruturas e medidas de dureza na região grosseira da ZAC, praticamente foram iguais, independente do aporte de calor. Os resultados do ensaio de impacto realizado à -25ºC, com e sem tratamento térmico, não sofreram alterações significativas para os valores das energias absorvidas na ZAC. Já a -10ºC a mudança foi mais significativa. O aspecto da morfologia da fratura na região de granulação grosseira da ZAC, após o ensaio de impacto, foi coerente para os quatro aportes de calor utilizados na soldagem. / It was studied in this report the microstructure, hardness and impact resistance in High Strength Low Alloyed (HSLA) steel in HAZ. The submerged are weld metals were made, using corrent of 600A, are voltage of 25V and travel speed of 25,5; 20,9; 24; and 19,5 cm/min. The USI-SAC-50 steel was used in present report. Four different heat input 3,53; 3,75; 4,24 and 4,61 kJ/mm were used to weld, produced significant changes in the coarse heat affected zone (HAZ) microstructure morphology, and this effect promoted changes on the hardness and the impact results at -25°C and -10°C. Using stress reliev treatment at 580°C for one hour, has changed the microstructure morphology in the coarse heat affected zone and the hardness measurements becames quite similar, therefore independent of the heat input. At -25°C the impact results has shown no variations with the stress reliev heat treatment. However, there were significant changes in the impact results at -10°C. After the impact test, the aspect of morphology facture in the coarse heat affected zone (HAZ), was coherent for the four different heat input, were used to weld.

Concrete structures may be subjected to dynamic loading during their service life. Understanding the dynamic properties of concrete structures is becoming critical because of the increased concern about the dynamic loading of both civilian and military structures, and especially, the recent increase in terrorist attacks on structures. Fiber reinforced concrete (FRC) is known to exhibit superior performance in its post-peak energy absorption capacity, (i.e., toughness) under flexural and tensile loading. However, the behavior of fiber reinforced concrete under compressive impact has not previously been investigated. In the present research, the response of fiber reinforced concrete was investigated over the full strain rate regime, from static loading to high strain rate loading, and finally to impact loading. The compressive toughness of FRC under static loading was studied using an existing Japanese standard (JSCE SF-5). Then, a test method for FRC under compressive impact loading was developed, involving the use of a high speed video camera system to measure the deformation of FRC cylinders under compressive impact. The strain rate sensitivity of FRC in both flexure and compression was also fully investigated. FRC was found to have higher strengths under impact loading (both flexural and compressive) than under static loading. The compressive toughness under impact loading increased due to the high peak load and the high strain capacity. FRC under flexural impact loading showed a greater strength improvement than under static flexure. FRC displays a much higher Dynamic Improvement Factor (DIF) under flexural impact than under compressive impact. It gave an overall higher performance under impact than under static loading. It also exhibited a higher strain rate sensitivity than plain concrete in both compression and flexure. Damage analysis, in terms of loss of strain energy, was carried out based on damage mechanics principles. Damage was found to increase with increasing strain rate. A new constitutive model was proposed to account for the relationship between DIF (Comp) and strain rate and the data derived from the model were found to be consistent with the experimental results.

Concrete structures may be subjected to dynamic loading during their service life. Understanding the dynamic properties of concrete structures is becoming critical because of the increased concern about the dynamic loading of both civilian and military structures, and especially, the recent increase in terrorist attacks on structures. Fiber reinforced concrete (FRC) is known to exhibit superior performance in its post-peak energy absorption capacity, (i.e., toughness) under flexural and tensile loading. However, the behavior of fiber reinforced concrete under compressive impact has not previously been investigated. In the present research, the response of fiber reinforced concrete was investigated over the full strain rate regime, from static loading to high strain rate loading, and finally to impact loading. The compressive toughness of FRC under static loading was studied using an existing Japanese standard (JSCE SF-5). Then, a test method for FRC under compressive impact loading was developed, involving the use of a high speed video camera system to measure the deformation of FRC cylinders under compressive impact. The strain rate sensitivity of FRC in both flexure and compression was also fully investigated. FRC was found to have higher strengths under impact loading (both flexural and compressive) than under static loading. The compressive toughness under impact loading increased due to the high peak load and the high strain capacity. FRC under flexural impact loading showed a greater strength improvement than under static flexure. FRC displays a much higher Dynamic Improvement Factor (DIF) under flexural impact than under compressive impact. It gave an overall higher performance under impact than under static loading. It also exhibited a higher strain rate sensitivity than plain concrete in both compression and flexure. Damage analysis, in terms of loss of strain energy, was carried out based on damage mechanics principles. Damage was found to increase with increasing strain rate. A new constitutive model was proposed to account for the relationship between DIF (Comp) and strain rate and the data derived from the model were found to be consistent with the experimental results.

A partir de um alerta internacional emitido pelas autoridades sanitárias francesas no ano de 2010 com respeito a altas taxas de ruptura de implantes mamários da marca Poly Implant Prothèse (PIP), a Agência de Vigilância Sanitária brasileira (ANVISA) suspendeu a importação, distribuição, comércio e uso destes implantes no país. Visando manter a qualidade destes produtos no mercado brasileiro, a partir de março de 2012 – conforme publicado pelo Instituto Nacional de Metrologia (INMETRO) – foi instituída a certificação compulsória dos implantes mamários e em seguida definidos os ensaios através dos quais os implantes mamários devem ter sua conformidade avaliada, sendo esses ensaios mecânicos e químicos. Este trabalho apresenta o desenvolvimento de equipamentos e metodologia para avaliação da conformidade de dois ensaios mecânicos em implantes mamários: ensaio de fadiga e ensaio de resistência ao impacto. Duas normas foram utilizadas para o processo de acreditação: ISO 14607 – Non - active surgical implants – Mammary implants – Particular Requirements, e ABNT NBR ISO 14607 – Implantes cirúrgicos não ativos – Implantes mamários – Requisitos particulares. Os equipamentos utilizados foram desenvolvidos e construídos ao longo do desenvolvimento deste estudo e os testes foram realizados em implantes mamários da marca PIP obtidos junto a ANVISA. A primeira etapa consistiu em organizar os documentos necessários para acreditação junto ao INMETRO e, após, ensaios os ensaios foram realizados. Ao todo trinta e cinco implantes foram ensaiados – 31 na primeira parte do trabalho e 04 na segunda – e analisados em lupa para verificação de defeitos causados pelos testes como: fraturas, cortes, alteração de forma, entre outros. Os equipamentos e metodologia desenvolvida atendem os requisitos de ambas as normas e permitem avaliação de conformidade de próteses mamárias comercializadas no país, no que diz respeito ao ensaio de fadiga e resistência ao impacto. / Due an international alert issued by French authorities in 2010 regarding high rupture rate of breast implants related to Poly Implant Prothèse (PIP), the Brazilian Health Surveillance Agency has suspended the importation, distribution, commercialization and use of these implants into Brazil. In order to maintain the quality of these products in Brazilian market, on March 2012 – according published by National Institute of Metrology – it has been decided for compulsory certification of breast implants and then defined the tests through which these products have to be submitted for its conformity assessment, being these mechanical and chemical tests. This dissertation evaluates the development and methodology for conformity assessment of two mechanical tests on breast implants: fatigue and impact resistance test. The process was based on two standards: ISO 14607 and ABNT NBR ISO – Non - active surgical implants – Mammary implants – Particular Requirements. The equipment used was developed in the laboratory during the realization of this study and the tests were performed on implants produced by PIP provided by National Sanitary Surveillance Agency. It started with the organization of the documents to be sent to National Institute of Metrology, in order to ask the accreditation and then tests were performed. Thirty five implants were tested – 31 on first part of the work and 04 on the second one – and then analyzed to detect any anomaly that could be considered a defect such as: rupture, cuts, shape alteration, etc. The equipment and methodology has met the requirements from both standards and enable conformity assessment of breast implants commercialized in Brazil, regarding to fatigue and impact resistance tests.

A partir de um alerta internacional emitido pelas autoridades sanitárias francesas no ano de 2010 com respeito a altas taxas de ruptura de implantes mamários da marca Poly Implant Prothèse (PIP), a Agência de Vigilância Sanitária brasileira (ANVISA) suspendeu a importação, distribuição, comércio e uso destes implantes no país. Visando manter a qualidade destes produtos no mercado brasileiro, a partir de março de 2012 – conforme publicado pelo Instituto Nacional de Metrologia (INMETRO) – foi instituída a certificação compulsória dos implantes mamários e em seguida definidos os ensaios através dos quais os implantes mamários devem ter sua conformidade avaliada, sendo esses ensaios mecânicos e químicos. Este trabalho apresenta o desenvolvimento de equipamentos e metodologia para avaliação da conformidade de dois ensaios mecânicos em implantes mamários: ensaio de fadiga e ensaio de resistência ao impacto. Duas normas foram utilizadas para o processo de acreditação: ISO 14607 – Non - active surgical implants – Mammary implants – Particular Requirements, e ABNT NBR ISO 14607 – Implantes cirúrgicos não ativos – Implantes mamários – Requisitos particulares. Os equipamentos utilizados foram desenvolvidos e construídos ao longo do desenvolvimento deste estudo e os testes foram realizados em implantes mamários da marca PIP obtidos junto a ANVISA. A primeira etapa consistiu em organizar os documentos necessários para acreditação junto ao INMETRO e, após, ensaios os ensaios foram realizados. Ao todo trinta e cinco implantes foram ensaiados – 31 na primeira parte do trabalho e 04 na segunda – e analisados em lupa para verificação de defeitos causados pelos testes como: fraturas, cortes, alteração de forma, entre outros. Os equipamentos e metodologia desenvolvida atendem os requisitos de ambas as normas e permitem avaliação de conformidade de próteses mamárias comercializadas no país, no que diz respeito ao ensaio de fadiga e resistência ao impacto. / Due an international alert issued by French authorities in 2010 regarding high rupture rate of breast implants related to Poly Implant Prothèse (PIP), the Brazilian Health Surveillance Agency has suspended the importation, distribution, commercialization and use of these implants into Brazil. In order to maintain the quality of these products in Brazilian market, on March 2012 – according published by National Institute of Metrology – it has been decided for compulsory certification of breast implants and then defined the tests through which these products have to be submitted for its conformity assessment, being these mechanical and chemical tests. This dissertation evaluates the development and methodology for conformity assessment of two mechanical tests on breast implants: fatigue and impact resistance test. The process was based on two standards: ISO 14607 and ABNT NBR ISO – Non - active surgical implants – Mammary implants – Particular Requirements. The equipment used was developed in the laboratory during the realization of this study and the tests were performed on implants produced by PIP provided by National Sanitary Surveillance Agency. It started with the organization of the documents to be sent to National Institute of Metrology, in order to ask the accreditation and then tests were performed. Thirty five implants were tested – 31 on first part of the work and 04 on the second one – and then analyzed to detect any anomaly that could be considered a defect such as: rupture, cuts, shape alteration, etc. The equipment and methodology has met the requirements from both standards and enable conformity assessment of breast implants commercialized in Brazil, regarding to fatigue and impact resistance tests.

A partir de um alerta internacional emitido pelas autoridades sanitárias francesas no ano de 2010 com respeito a altas taxas de ruptura de implantes mamários da marca Poly Implant Prothèse (PIP), a Agência de Vigilância Sanitária brasileira (ANVISA) suspendeu a importação, distribuição, comércio e uso destes implantes no país. Visando manter a qualidade destes produtos no mercado brasileiro, a partir de março de 2012 – conforme publicado pelo Instituto Nacional de Metrologia (INMETRO) – foi instituída a certificação compulsória dos implantes mamários e em seguida definidos os ensaios através dos quais os implantes mamários devem ter sua conformidade avaliada, sendo esses ensaios mecânicos e químicos. Este trabalho apresenta o desenvolvimento de equipamentos e metodologia para avaliação da conformidade de dois ensaios mecânicos em implantes mamários: ensaio de fadiga e ensaio de resistência ao impacto. Duas normas foram utilizadas para o processo de acreditação: ISO 14607 – Non - active surgical implants – Mammary implants – Particular Requirements, e ABNT NBR ISO 14607 – Implantes cirúrgicos não ativos – Implantes mamários – Requisitos particulares. Os equipamentos utilizados foram desenvolvidos e construídos ao longo do desenvolvimento deste estudo e os testes foram realizados em implantes mamários da marca PIP obtidos junto a ANVISA. A primeira etapa consistiu em organizar os documentos necessários para acreditação junto ao INMETRO e, após, ensaios os ensaios foram realizados. Ao todo trinta e cinco implantes foram ensaiados – 31 na primeira parte do trabalho e 04 na segunda – e analisados em lupa para verificação de defeitos causados pelos testes como: fraturas, cortes, alteração de forma, entre outros. Os equipamentos e metodologia desenvolvida atendem os requisitos de ambas as normas e permitem avaliação de conformidade de próteses mamárias comercializadas no país, no que diz respeito ao ensaio de fadiga e resistência ao impacto. / Due an international alert issued by French authorities in 2010 regarding high rupture rate of breast implants related to Poly Implant Prothèse (PIP), the Brazilian Health Surveillance Agency has suspended the importation, distribution, commercialization and use of these implants into Brazil. In order to maintain the quality of these products in Brazilian market, on March 2012 – according published by National Institute of Metrology – it has been decided for compulsory certification of breast implants and then defined the tests through which these products have to be submitted for its conformity assessment, being these mechanical and chemical tests. This dissertation evaluates the development and methodology for conformity assessment of two mechanical tests on breast implants: fatigue and impact resistance test. The process was based on two standards: ISO 14607 and ABNT NBR ISO – Non - active surgical implants – Mammary implants – Particular Requirements. The equipment used was developed in the laboratory during the realization of this study and the tests were performed on implants produced by PIP provided by National Sanitary Surveillance Agency. It started with the organization of the documents to be sent to National Institute of Metrology, in order to ask the accreditation and then tests were performed. Thirty five implants were tested – 31 on first part of the work and 04 on the second one – and then analyzed to detect any anomaly that could be considered a defect such as: rupture, cuts, shape alteration, etc. The equipment and methodology has met the requirements from both standards and enable conformity assessment of breast implants commercialized in Brazil, regarding to fatigue and impact resistance tests.

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No. of bitstreams: 2 Dissertação - Mariana Rezende de Barros - 2016.pdf: 5601059 bytes, checksum: 953996d14e3ede469126893d305e59ce (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-08-01 / Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG / Modern agriculture requires productivity, efficiency and quality. Therefore, there is need for the application of agricultural lime to correct the soil acidity. The Midwest was appointed as the largest producer of agricultural limestone, with 38.2% and Goiás and holder of 11.6%. In limestone beneficiation process is the generation of fine material (through in # 400 (0.035 mm)), which does not have economic viability in the agricultural, metallurgical and calcination. This is because this particle size of particle decreases the percolation of gas in blast furnaces and has slow settling when used in agriculture, can be transported by wind generating environmental liabilities. Briquetting is to agglomeration of fine particles by pressure, aided or not by a binder, allowing obtaining not only compacts, but with size, shape and mechanical parameters. The objective of this study was to investigate the binding of fine limestone through briquetting through use of a specific type known to have very fine grained (<0.075 mm) using organic and inorganic binders. Agglomeration of fine limestone through the briquetting was conducted by varying the amounts of water (used as inorganic binding agent) 0; 5; 7.5; 10; 12.5% and 2.5; 5; 7.5 and 8.5% organic binders - Molasses Soy and Treacle of cane sugar. The limestone powder and briquettes were analyzed chemically and physically by Scanning Electron Microscopy, Energy Dispersive X-ray (EDS), chemical and particle size analysis. The briquettes were subjected to impact resistance test, resistance to breakdown in water and compressive strength. The best results in impact resistance tests were analyzed and from these results of other tests were performed. The results of mechanical impact resistance were analyzed statistically by analysis of variance (ANOVA), checking if the binder content and factors influenced the agglomeration of the mineral. In addition to lowering the environmental liabilities, the briquettes will also generate profits for the mining industry and can offer a co-product with similar characteristics to the product originally marketed. / A agricultura moderna exige produtividade, eficiência e qualidade. Por isso, há necessidade da aplicação do calcário agrícola para corrigir a acidez dos solos. O Centro- Oeste foi apontado como o maior produtor de calcário agrícola, com 38,2% e Goiás sendo detentor de 11,6%. No processo de beneficiamento do calcário ocorre a geração de material fino (passante em 400# (0,035 mm)), que não possui viabilidade econômica nos setores agrícola, metalúrgico e de calcinação. Isso ocorre porque essa granulometria de partícula diminui a percolação de gases nos altos-fornos e possui sedimentação lenta quando empregada na agricultura, podendo ser transportada pelo vento gerando passivo ambiental. A briquetagem consiste na aglomeração de partículas finas através de pressão, auxiliada ou não por aglutinantes, permitindo obtenção de produtos não só compactados, porém com forma, tamanho e parâmetros mecânicos. O objetivo do trabalho foi verificar a aglomeração dos finos de calcário por meio da briquetagem através aproveitamento de um tipo específico conhecido por possuir granulometria bastante fina (< 0,075 mm) utilizando aglomerantes orgânicos e inorgânicos. A aglomeração dos finos de calcário através da briquetagem, foi realizada variando as dosagens de água (utilizada como agente aglomerante inorgânico) de 0; 5; 7,5; 10; 12,5% e 2,5; 5; 7,5 e 8,5% de aglomerantes orgânicos – Melaço de Soja e Melado de Cana-de-açúcar. O calcário em pó e os briquetes foram analisados química e fisicamente por meio de Microscopia Eletrônica de Varredura, Energia Dispersiva de Raios-X (EDS), análises química e granulométrica. Os briquetes foram submetidos a testes de resistência ao impacto, resistência à decomposição em água e resistência a compressão. Os melhores resultados obtidos no teste de resistência ao impacto foram analisados e a partir desses resultados foram realizados os demais testes. Os resultados de resistência mecânica ao impacto foram analisados estatisticamente através da análise de variância (ANOVA), verificando se os fatores aglomerantes e teor influenciaram na aglomeração do mineral. Além de diminuir o passivo ambiental, os briquetes também irão gerar lucros para a indústria mineral, podendo oferecer um coproduto com características semelhantes ao produto originalmente comercializado.

Concrete structures may be subjected to dynamic loading during their service life. Understanding the dynamic properties of concrete structures is becoming critical because of the increased concern about the dynamic loading of both civilian and military structures, and especially, the recent increase in terrorist attacks on structures. Fiber reinforced concrete (FRC) is known to exhibit superior performance in its post-peak energy absorption capacity, (i.e., toughness) under flexural and tensile loading. However, the behavior of fiber reinforced concrete under compressive impact has not previously been investigated. In the present research, the response of fiber reinforced concrete was investigated over the full strain rate regime, from static loading to high strain rate loading, and finally to impact loading. The compressive toughness of FRC under static loading was studied using an existing Japanese standard (JSCE SF-5). Then, a test method for FRC under compressive impact loading was developed, involving the use of a high speed video camera system to measure the deformation of FRC cylinders under compressive impact. The strain rate sensitivity of FRC in both flexure and compression was also fully investigated. FRC was found to have higher strengths under impact loading (both flexural and compressive) than under static loading. The compressive toughness under impact loading increased due to the high peak load and the high strain capacity. FRC under flexural impact loading showed a greater strength improvement than under static flexure. FRC displays a much higher Dynamic Improvement Factor (DIF) under flexural impact than under compressive impact. It gave an overall higher performance under impact than under static loading. It also exhibited a higher strain rate sensitivity than plain concrete in both compression and flexure. Damage analysis, in terms of loss of strain energy, was carried out based on damage mechanics principles. Damage was found to increase with increasing strain rate. A new constitutive model was proposed to account for the relationship between DIF (Comp) and strain rate and the data derived from the model were found to be consistent with the experimental results. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Neste trabalho foram estudadas as microestruturas, dureza, e resistência ao impacto em aço alta resistência e baixa liga (ARBL) na ZAC. O processo de soldagem foi por arco submerso, utilizando corrente de 600A, tensão de 25V, velocidade de soldagem de 25,5; 24; 20,94; e 19,5 cm/min. Utilizou-se chapa de aço USI-SAC-50. Os quatro aportes de calor produzidos 3,53; 3,75; 4,24; 4,61 kJ/mm, permitiram variações microestruturais na região de granulação grosseira da ZAC, promovendo variações nas medidas de durezas e nos resultados do ensaio de impacto medido à -25ºC e -10ºC. Quando realizado o tratamento térmico de alívio de tensões a 580ºC por 1 hora, as morfologias das microestruturas e medidas de dureza na região grosseira da ZAC, praticamente foram iguais, independente do aporte de calor. Os resultados do ensaio de impacto realizado à -25ºC, com e sem tratamento térmico, não sofreram alterações significativas para os valores das energias absorvidas na ZAC. Já a -10ºC a mudança foi mais significativa. O aspecto da morfologia da fratura na região de granulação grosseira da ZAC, após o ensaio de impacto, foi coerente para os quatro aportes de calor utilizados na soldagem. / It was studied in this report the microstructure, hardness and impact resistance in High Strength Low Alloyed (HSLA) steel in HAZ. The submerged are weld metals were made, using corrent of 600A, are voltage of 25V and travel speed of 25,5; 20,9; 24; and 19,5 cm/min. The USI-SAC-50 steel was used in present report. Four different heat input 3,53; 3,75; 4,24 and 4,61 kJ/mm were used to weld, produced significant changes in the coarse heat affected zone (HAZ) microstructure morphology, and this effect promoted changes on the hardness and the impact results at -25°C and -10°C. Using stress reliev treatment at 580°C for one hour, has changed the microstructure morphology in the coarse heat affected zone and the hardness measurements becames quite similar, therefore independent of the heat input. At -25°C the impact results has shown no variations with the stress reliev heat treatment. However, there were significant changes in the impact results at -10°C. After the impact test, the aspect of morphology facture in the coarse heat affected zone (HAZ), was coherent for the four different heat input, were used to weld.