A avaliação da integridade estrutural de dutos pelo uso de corpos-de-prova laboratoriais depende da escolha de corpos-de-prova de geometrias que representem condições de restrições plásticas na frente da trinca, similares às encontradas nas condições operacionais dos dutos. O Núcleo de Ensaios de Materiais e Análise de Falhas, NEMAF do SMM, EESC-USP vem realizando pesquisas para o desenvolvimento de corpos-de-prova e metodologias experimentais que melhor represente esta situação. Entretanto, no caso de dutos existem situações onde a geometria e o tamanho do corpo-de-prova são limitados pelas dimensões do duto. Este trabalho apresenta o desenvolvimento e aplicação de espécimes SE(T) em aço API 5L X70, avaliando a influência da geometria e dimensões do corpo-de-prova na tenacidade à fratura do citado aço, sendo este utilizado na fabricação de dutos para transporte de gás e petróleo. Para isto, foram obtidas curvas de resistência à propagação dúctil de trincas, curvas J-R\'s, utilizando a metodologia do espécime único (single specimen) em conjunto com a técnica da variação da flexibilidade elástica (unloading elastic compliance), medida na boca da trinca (CMOD) que fornece ao mesmo tempo a área plástica abaixo da curva de carregamento versus deslocamento e o tamanho da trinca, segundo a norma de ensaios ASTM E1820-05. Foram ensaiados corpos-de-prova SE(T) com trincas rasa (a/W=0,2) e profunda (a/W=0,5) e razão W/B de 2,5 e 1,0, com a finalidade de garantir que o ensaio seja realizado em dominância de um estado plano de deformação como recomendado pela referida norma, para outros tipos de corpos-de-prova. Dos resultados observou-se que, independente do tamanho de trinca inicial adotado, não foram observadas diferenças significativas nas curvas J-R. Este fato pode ser comprovado nos casos de W/B = 2,5 e 1,0, sendo obtidas curvas J-R similares para cada caso, independente do valor de a/W. Entretanto, na grande maioria dos CDP\'s, foi obtida uma propagação dúctil de trinca anômala, ou seja, trincas que apresentam um tunelamento acentuado, decorrente de um elevado estado de tensão plana próximo das laterais, mesmo com o entalhe lateral de 20% da espessura. Os corpos-de-prova com W/B = 1,0 foram capazes de produzir curvas J-R, sem que as trincas apresentassem tunelamento e que os valores médios de trinca (ai e af) medidos conforme a norma (ASTM, 2005), são bastante próximos dos valores obtidos pelo método da variação de flexibilidade elástica. As razões para este fato são discutidas em detalhes. De um modo geral as delaminações, quando existente, não permitem uma correta medição do tamanho de trinca. Ainda, contrário à observação de outros pesquisadores, neste trabalho, foi observado que em vários casos as delaminações induziram fratura instável. / The evaluation of pipes´ structural integrity from laboratories specimens depends on choosing the right specimen geometry that is able to present the conditions of plastic constrain at the crack tip, similar to the one found in the pipes´ operational conditions. The NEMAF Group from SMM, EESC-USP has been performing studies in this area, trying to develop specimen´s geometry that is able to represent this situation, as well as the necessary experimental methodologies to evaluate the fracture toughness of pipes. However, in some cases, the pipe size is a limiting factor in determining the specimen size and geometry. In this work is presented the development and application of specimens SE(T), evaluating the influence of the geometry and dimensions of the specimens on the fracture toughness of API 5L X70 steel, regularly used in the pipes for gas and petroleum transportation. Therefore, the resistance curves to ductile crack propagation, J-R`s curves, using the single specimen methodology, together with the variation of the elastic compliance technique (multiple unloading), measure at the crack mouth (CMOD) that provides both the plastic area under the load x displacement curve and crack size, according to the ASTM E1820-05 standard. The SE(T) specimens with shallow (a/W=0.2) and deep (a/W=0.5) cracks and W/B ratio of 2.5 and 1.0 trying to reduce the amount of plastic deformation and a straight crack front, as well as a dominance of a plane strain state at the crack tip, as recommended by the ASTM E1820-05 standard for other specimens type. From the results it was observed that, independent of the initial a/W, no significant differences were observed in the J-R curves. This fact is verified in both cases, this is, W/B = 2.5 and 1.0. However, in the great majority of CDP\'s with W/B = 2.5, it was obtained an anomalous crack propagation during testing, in other words, they presented an accentuated tunneling due to a high plane tension state near the CDP´s lateral faces, even with the side groove of 20% thickness. The specimens with W/B = 1.0 were capable to produce J-R curves with straight crack fronts, this is, without tunneling, allowing the measurement of medium values of the crack (ai e af) according to the ASTM E1820-05 standard. The reasons for this fact are discussed in details in this work. In general, the split, when present, did not allow a correct crack size measurement. Still, contrary to the other researchers\' observation, in this work, it was observed that in several cases the splits were able to induced unstable fracture.

Aplicações de alto desempenho, como as de dutos utilizados no transporte de derivados de petróleo, exigem materiais com uma combinação excepcional de propriedades mecânicas, dentre as quais, elevada resistência mecânica, tenacidade e resistência à fadiga. O aço API 5L X70 com adição de nióbio apresenta-se, quando comparado com o API 5L X70 padrão, como sendo uma opção para a melhora em seu processo de fabricação, sendo sua composição química diferenciada, devido a um maior teor de nióbio. A Arcelor Mittal Tubarão tem mostrado interesse em fabricar aços API X70/X80, sem a adição de V e com adições de Nb acima do recomendado pela Petrobras. O objetivo principal deste trabalho é o estudo da resistência mecânica e de tenacidade à fratura de dois aços API 5L X70, com teores de Nb de 0,06% e Nb de 0,09% em peso, processados conforme processo HSM Arcelor Mittal Tubarão. Para o atendimento deste objetivo, serão executadas a caracterização microestrutural conforme norma ASTM E3, ensaios de tração conforme ASTM E8M e ensaios de tenacidade à fratura conforme a norma ASTM E1820 com obtenção das curvas J-R\'s. Foram retirados corpos de prova da região de material base, região da solda e zona termicamente afetada. A partir dos resultados obtidos observa-se que o processo de laminação controlada a quente da Arcelor Mittal, produziu microestruturas bastante similares para ambas as composições, produzindo parâmetros de resistência mecânica similares e que atenderam o especificado pela Norma API 5L X70, nível PSL2. As soldas se apresentaram, a partir de valores de dureza, ligeiramente superiores ao do metal base (overmatch), sendo o resultado de microestruturas bastante similares. Os ensaios para obtenção das curvas J-R foram capazes de apresentar resultados representativos da resistência à propagação dúctil de trinca, para as espessuras de tubos estudadas. Estes resultados indicaram elevada resistência a propagação dúctil de trinca em ambos os aços, sendo que, o MB do aço NNb apresentou resistência superior ao ANb. O MS apresentou curvas J-R bem inferiores às do MB e ZTA. Estas diferenças foram atribuídas a composição microestrutural de cada região. / High performance applications such as pipelines used to transport oil products require materials with an exceptional combination of mechanical properties, such as high mechanical strength, toughness and fatigue resistance. The API 5L X70 steel with enhanced niobium as an option to the production of this type of HSLA steel. Arcelor Mittal, Tubarão/Brazil has great interest in producing API 5L X70/X80 steels, without V and with Nb content above the recommended by Petrobras. Thus, the main objective of this thesis is the study of the mechanical strength and fracture toughness of API 5L X70 steel with Nb content of 0.06% Nb and 0.09% by weight processed as HSM Arcelor Mittal Tubarão process. To meet this goal, microstructural characterization following the ASTM E3, tensile tests following the ASTM E8M and Elastic Plastic Fracture toughness testing, according to ASTM E1820, were carried out. Specimens were taken from the base material region, weld bead and heat affected zone. From the results obtained it was observed that the controlled hot rolling process from ArcelorMittal, produced very similar microstructures for both compositions, as a consequence similar mechanical resistance and both met the criteria specified by the API Standard 5L X70, PSL2 level. The produced girth welds presented hardness values slightly higher than those from the base metal (overmatch), and resulted in very similar microstructures. The fracture toughness tests were able to provide valid JR curves that are representative results of resistance to ductile crack propagation for this pipe thickness. Both steels presented resistance to ductile crack propagation, and that the MB of the NNB steel showed superior resistance to the ANb steel. MS showed the lowest J-R curves, while MB and ZTA presented similar behavior. These differences were attributed to microstructural composition of each region.

Este trabalho apresenta o desenvolvimento e aplicação de espécimes SE(T) em aço API X60 para avaliação de integridade estrutural em dutos condutores de gás e petróleo, o qual consiste na implantação de três técnicas que forneçam as curvas de resistência à propagação dútil de trincas, curvas J-Rs. As metodologias utilizadas foram a da variação da flexibilidade elástica, da queda de potencial elétrico e da normalização linear da carga, nas quais duas análises são verificadas para obtenção da área plástica abaixo da curva de carregamento. A primeira, através da medida do deslocamento da linha de carga e a segunda, pelo deslocamento do extensômetro colocado na boca da trinca. Foram ensaiados corpos de prova SE(T) com trincas rasa (a/W = 0,2) e profunda (a/W = 0,5) e os resultados obtidos permitiram observar a iniciação da propagação por rasgamento dúctil e discutir os limites das metodologias aplicadas. Os resultados mostraram que é possível obter as curvas J-Rs medindo o deslocamento na boca da trinca, podendo-se converter os deslocamentos de CMOD em deslocamentos do LLD. Foi constatada também que a técnica de normalização linear da carga é a que possibilitou o menor tempo de preparação e execução do ensaio, por utilizar apenas a medição do CMOD e não necessitar da realização dos descarregamentos. A variação da flexibilidade elástica é uma técnica rápida e confiável e não sofre alterações devido às delaminações. Já a técnica de queda do potencial elétrico se mostrou a mais consistente para o caso de a/W = 0,5, porém no caso de trincas curtas, a plasticidade desenvolvida na frente da trinca influencia nas medições causando imprecisões. As curvas J-Rs são deslocadas para a esquerda quando o tamanho inicial de trinca é reduzido, isto é, ocorre um aumento na energia de iniciação da propagação, JIC. / This work presents the development and application of SE(T) type specimen for structural integrity evaluation of pipeline steels used for gas and oil transportation, and it consists of the implementation of different techniques to provide the crack growth resistance curves, J-R curves. The methodologies used for crack growth measurement were: the elastic compliance, the electrical potential drop and the linear normalization techniques. Two techniques to provide the plastic area, Apl under the load versus displacement curve were used to evaluate Jpl, one based on the load line displacement, LLD, and the other based on the crack mouth opening displacement, CMOD. SE(T) specimens with two different initial crack size, denominate as shallow crack (a0/W = 0.2) and deep crack (a0/W = 0.5). The obtained results allowed the determination of the ductile tearing initiation point and to discuss the limits of the methodologies applied. It was proved be possible to get J-R curves using only one extensometer to measure the CMOD, which provides both crack size and Apl. The linear normalization technique is the one that provided the lower preparation and testing time, since there is no need of multiples unloading for crack growth measurement. The elastic compliance is a very easy, fast and reliable technique, and it is not sensible to the effect of the occurrence of delaminations, as it was the linear normalization technique. The electrical potential drop technique proved to very consistent for a0/W = 0.5, however in the case of shallow cracks the developed plasticity at the crack tip affected the measurements. The J-R curves were displaced to the left as the initial crack size is reduced, this is, there is an increase in the energy for crack tearing initiation, JIC.

This thesis focuses on the description of 3D printing technologies using the FDM method, which uses deposition of molten thermoplastics and their subsequent cooling and solidification layer by layer. This unique structure then shows a strong anisotropy of mechanical properties and, as a result, their testing and print settings are very important. Tensile testing of plastic materials, including indicators of mechanical properties, are described in this thesis according to ČSN EN ISO standard. The practical part presents the concept of a device capable of performing these tests. The block diagram indicates the functional elements and the connections among them. Tensile strength test is described together with results processing. Necessary product documentation is also included.

This thesis is focused on assessment of fracture behaviour of heterogeneous welded joint. The goal is to determine fracture behaviour at the interface of ferritic base metal and austenitic weld metal at temperature of 255°C. This kind of weld is widely used at energy industry. Fracture toughness was evaluated using CT specimens with size 0,5T in order to determine the initiation values of stable crack propagation. Fracture behaviour of the weld is correlated with results of metallography and fractography analysis. Both light and scanning electron microscopy is used for fractography analysis. An assessment of fracture behaviour of the interface of the weld joint is first of all connected with a need of suitable location of cycled crack to the interface of metals. In the case of well-prepared crack the lowest values of J-integral are observed. In other cases of slight crack deviation from the notch plane fracture values increase. Due to a large scatter of mechanical properties of heterogeneous weld joints an increased number of test specimens is needed to obtain relevant and conservative fracture toughness values. Correlation of fracture toughness with the results of fractography analysis leads to clarification of the crack trajectory and to description of fracture mechanism.

A testing system MTS Tytron 250 with an original construction was bought at the Institute of Physics of Materials, AVCR v.v.i. The main aim of this diploma thesis was to obtain experiences with the controlling of the system and with its advantages and limitations. The tensile tests were performed on Al fibres with diameters of 125 micrometer, 180 micrometer a 500 micrometer, nylon fibres of 250 micrometer and 500 micrometer and tensile and cyclic tests on Al foil of 77 micrometer in thickness. It was found that the machine is suitable for testing of either subtle specimens with low loading forces or specimens with low stiffness as e.g. polymers or very long metallic or ceramic fibres. On the other side, the Tytrom system is not able to perform tests on specimens with a high stiffness and high loading forces. Material parameters were determined with a high reproducibility. Advantages and limitations of several types of subtle specimen's fixation into the grips were studied too.

Krebserkrankungen sind das Resultat komplexer Vorgänge und Veränderungen. Eine wichtige Variable in der Initialisierung ist die Interaktion zwischen Genotyp und Umwelt. Da Magenkarzinome zu den wenigen Krebserkrankungen gehören, bei denen im letzten Jahrhundert ein deutlicher Rückgang in der Inzidenz beobachtet werden konnte (Becker 2006), stellt sich die Frage, ob es Unterschiede in der genetischen Ausstattung von historischen Tumorgenomen im Vergleich zu rezenten gibt. Als typisches Zielgen für Tumormutationen wurde das Tumorsuppressorgen p53 untersucht. Au¬ßerdem wurde Helicobacter pylori (H. pylori) als Risikofaktor für die Entstehung von Magenkarzinomen in den historischen Proben identifiziert. Insgesamt standen 51 Gewebeproben von Magenkarzinompatienten aus den Medizinhistori¬schen Museen Berlin und Zürich, dem Pathologisch-anatomischen Bundesmuseum Wien sowie der anatomischen Sammlung der Universität Tartu zur Verfügung. Bei 47 Proben handelte es sich nach histologischer Diagnose um Magenkarzinome. Die Proben sind zwischen 50 und 180 Jahre alt und wurden in Konservierungsflüssigkeiten unbekannter Zusammensetzung gelagert. Von 45% der Proben konnten vollständige Sequenzen der Exons 5 bis 8 des p53-Gens generiert werden. Es konnten Veränderungen im Mutationsspektrum und in der Lokalisation der Mutationen in den historischen Proben im Vergleich zu rezenten Tumormutationen festgestellt werden. Die Mutationsfrequenz betrug 52%. Insgesamt wurden zehn verschiedene Mutationsereignisse in p53 bei elf verschiedenen Proben detektiert, wobei drei Proben von zwei Mutationen betroffen waren. Zwei Mutationen führen direkt (Q144X) bzw. indirekt (S166fs) zu der Entstehung von Stoppcodons. Zu einem Verlust des p53-Proteins bei gleichzeitiger Akquirierung onkogener Funktionen kommt es durch die Hotspot-Mutation R248W (Wang & El-Deiry 2007). Zu einer Zunahme der Funktionsfähigkeit (gain-of-function) kommt es außerdem durch die Mutation K291E. Die Mutation E271K ist an einer splice site lokalisiert, so dass das Exon nicht in die mRNA übernommen werden kann. Die Konsequenzen der anderen Mutationsereignisse sind nicht eindeutig belegt, scheinen aber einen geringeren Einfluss auf die Funktionalität von p53 zu haben. Abweichend zu rezenten Magenkarzinomen konnte die Mutation M246K als Hotspot der historischen Proben identifiziert werden. Insgesamt waren nur vier historische Mutationen bisher aus rezentem Magenkarzinomgewebe beschrieben, davon die Mehrheit in Studien mit asiatischen Patienten. Die veränderten Mutationen der historischen Magenkarzinome können als Hinweis auf Veränderungen in den karzinogen wirkenden Einflussfaktoren dienen, etwa eine veränderte Lebens- und Ernährungsweise durch die Einführung von Kühlmöglichkeiten für Lebensmittel. Der Risikofaktor H. pylori konnte in 70% der Gewebeproben sicher nachgewiesen werden. Der Anteil der Träger des Virulenzfaktors cag betrug 44%. 73% der Proben mit p53-Mutation waren nachweislich mit H. pylori und davon wiederum 63% mit einem cag-positiven Stamm infiziert. Die Infektion ermöglicht eine Teilerklärung für die untypische Lokalisation der Mutationen, da H. pylori-induzierte Mutationen seltener an Magenkarzinom-Hotspots vorkommen (Murakami et al. 1999). Es konnten keine resistenztypischen Mutationen gegen das Antibiotikum Clarithromycin in den historischen Geweben identifiziert werden. Die vorliegende Arbeit konnte p53-Mutationen und das Bakterium H. pylori in den historischen Gewebeproben identifizieren. Ein verändertes Mutationsspektrum und die veränderte Lokalisation der Mutationen geben den Hinweis, dass sich die Einflüsse auf die Entstehung der Magenkarzinome im letzten Jahrhundert verändert haben.

This study is made to determine the educational inequalities that exist in the schools of Wheeler County and to set up a plan that will help to equalize the educational opportunities for all the children in the county, on a basis well within its financial ability. The study consists of three phases of the problem of equalizing educational opportunities in the schools of Wheeler County. The first will consist of a study of the educational conditions of the schools, based upon the general population trends, scholastic trends, the per pupil load of each elementary classroom, the subject-pupil load of each high school teacher, and the qualification of the teachers according to college work. The second will consist of a financial survey of the schools based upon assessed valuations, tax rates, cost per scholastic, and outstanding bonded indebtedness. The third will be the formulating of a plan for the equalization of educational opportunities based upon the findings of the educational and financial surveys.

The purpose of this study has been to determine the nature and extent of educational opportunity offered to prison inmates in the Texas Department of Corrections, and as far as is possible, to evaluate the effectiveness of the program. Both primary and secondary data were used. Primary data were obtained by correspondence and personal interviews with TDC officials and staff members. Secondary data were obtained from annual reports submitted to the Texas Prison Board and the Board of Pardons and Paroles by the Department of Welfare, of which the Educational Department is a branch, from the Echo, prison inmate publication, and from mimeographed material prepared by prison officials.

The purpose of this study is to show that an awareness of modern architecture is developing in Dallas, Texas. This will be shown by an analysis of several recently constructed residential, civic, and commercial buildings. The contributions of American and European architects who have influenced our contemporary architecture are reviewed to in order to develop a background for this study. This will be shown by an analysis of several recently constructed residential, civic and commercial buildings.