Determinação experimental da tenacidade à fratura em baixas temperaturas de tubos de aço API 5L X70

Because of the great metallurgical advances, the welded tubes by HF / ERW (High Frequency / Electrical Resistance Welding) have played a more active role in the oil and gas, gradually replacing tubes produced by other processes (UOE, SAW, and others) to deep water applications, in high and extremely low temperatures, highpressure conditions and in highly corrosive environments. However, studies have revealed that defects in the welded joints are in one of main causes of failures in pipelines. Associated with damage external and the stringent requirements of this sector, the welded joints become particularly critical for his toughness and the determination of this particular property is fundamental. This study aims to evaluate the toughness of the HF / ERW pipes in HSLA steel API X70 class, used in pipelines transport systems of gas and oil from data obtained with CTOD tests (Crack Tip Opening Displacement). The main objectives of this project are: mechanical and microstructural characterization of steels API X70 manufactured in Brazil; and evaluation of the toughness of weld process by HF / ERW steel API X70 national. After having the tests done, mechanical, chemical and metallurgical, we have the conclusion that those pipe are in agreement to API 5L 42ª edition for X70MO and the toughness behaves like the expected

Avaliação da tenacidade à fratura em juntas soldadas circunferenciais de tubulações de processo

This work aims to analyze the toughness of a welded joint in the presence of a crack through the analysis of maximum tension the material can withstand the presence of this type of defect, since a discontinuity is likely to occur in this type of joint and its detection and its design is simple, using non-destructive testing techniques. The study will be conducted through the CTOD test - Crack-Tip Opening Displacement, with type specimens SE (B) - Single Edge Bend taken from a weld in the L-C position in relation to the length (longitudinal axis) of a test tube. The main idea is to simulate the welding conditions for the manufacture of industrial pipes, made in boiler shops (pipe-shop) within petrochemical plants. These pipes are often subject to operation with flammable and toxic subjected to high pressures and temperatures, where one can break the line can cause irreparable damage to the plant, the environment and the health of surrounding communities. With this study we evaluate whether the weld metal has the same properties as fracture toughness of the base material. This study shows the importance of using a qualified welding procedure for performing quality welds while maintaining the properties of the fracture toughness of the base metal. It was found from the results of tests using a welding procedure described for carrying out welding ensures mechanical properties very close to the base metal, which in terms of design is great, since one can ensure that the weld will the same characteristics of the base metal specified for the assembly of the pipe

Fractografia quantitativa e o conceito de tenacidade à fratura para a análise do efeitodo choque térmicos em TiO2

The present study evaluated the use of semicircular bending test (SCB) as an alternative to conventional bending test to examine the effect of thermal shock. Still, studies the behavior of fracture surfaces generated by monofractal behavior analysis, which allows us to evaluate the contributions of the microstructure and the mechanical context in forming reliefs during the crack propagation. The fractal analysis is made from elevation maps obtained by reconstruction method by extension of the focus stacks of digital images acquired in microscope. The specimens used were samples semicircular pressed TiO2 (rutile) with and without heat shock, prepared for testing mode I loading. Were also produced, specimens in the form of bars for Weibull statistical analysis. From the three-point bending test, we found the variation of fracture toughness between the samples after the heat shock and natural condition. The SCB test was feasible for the analysis of thermal shock resistance. The results showed that the value of the fracture toughness decreases as the heat shock treatment

Efeito de diferentes espessuras, técnicas de aplicação e protocolos de resfriamento na resistência à fratura da cerâmica de cobertura aplicada sobre infraestrutura de y-tzp

Pós-graduação em Odontologia Restauradora - ICT

Efeito de protocolos de cimentação na carga de fratura para uma cerâmica de dissilicato de lítio

Pós-graduação em Odontologia Restauradora - ICT

Clima e vulnerabilidade socioespacial: uma avaliação dos fatores de risco na população urbana do município de São Luís (MA)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A gênese e a distribuição socioespacial das chuvas no município de Ubatuba-SP

This monograph aims to contribute to the understanding and analysis of extreme events and its correlation with anthropogenic actions, in order to understand the levels of human interference in the environment and to identify potential social and environmental damage that such events may result in Ubatuba, located on the northern coast of São Paulo state. Therefore, two strategies were established, on one hand, episodic analysis of extreme weather events, and on the other, the analysis of the impact of atmospheric phenomena in everyday society. In this case we gave greater emphasis to analysis years that had higher total rainfall. In this sense, the research was based on the standard deviation technique and percentages, which supported to characterize the exceptional rainy years, in addition, use of rhythm analysis technique that has helped to identify the active atmospheric systems. From a qualitative point of view, field works were carried out in order to make use of news by the local press and civil defense for years considered extreme (positive standard deviation). From this, it was analyzed how the extreme episodes of rainfall trigger repercussions in geographic space. Also the spatial distribution of rainfall were carried out by means of quantitative analysis of six rain gauges. It was found that the highest occurrences of impacts, are located in the central areas of the city, as well as the highest rainfall totals. In fact, Ubatuba/SP suffers from very high rainfall totals and has a singularity on the climate...

Tratamento ortodôntico da agenesia de incisivo lateral superior com envolvimento de fratura radicular de incisivo central superior

Patients with agenesis of maxillary lateral incisor must have in your planning functional and aesthetic considerations, important to the success of the treatment, regardless of whether the choice of treatment is closing or opening and maintenance of space for rehabilitation with prosthesis. This choice will depend on factors such as skeletal and tooth structure and profile. Children and adolescents are the group of individuals most exposed to trauma and fracture of the maxillary lateral incisor due to the activities they perform. Proper diagnosis and good treatment are essential to the success of the treatment. This article aims to report a case of agenesis of the maxillary lateral incisor along with the involvement of a root fracture of the maxillary central incisor. The orthodontic treatment was successfully finished with a favorable prognosis for the fractured incisor to stay in a esthetic and functional position.

Diferença, dispersão e fragmentação socioespacial: explorações metropolitanas em Brasília e Curitiba = Différence, dispersion et fragmentation sociospatiale : explorations métropolitaines à Brasilia et Curitiba

Pós-graduação em Geografia - FCT

Estudo mecânico comparativo da estabilização de fratura ilíaca com dois tipos de implantes (parafusos com placa de compressão dinâmica e parafusos associados ao polimetilmetacrilato) em hemipelves caninas sintéticas

Pós-graduação em Cirurgia Veterinária - FCAV

Influência da geometria oclusal e material restaurador na carga para fratura e distribuição de tensões em coroas totais

Pós-graduação em Odontologia Restauradora - ICT

Avaliação da resistência à fratura de próteses fixas temporárias reforçadas por uma malha experimental

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Pinos transcorticais e gesso associados à aplicação local de plasma rico em plaquetas no tratamento de fratura do III metatarsiano em potro

In horses less than one year of age fractures of the third metacarpal bone (McIII) or metatarsal bone III (MtIII) are mainly attributed to trauma. Open reduction and internal fixation are the most common treatment method. A Quarter Horse filly with three months of age, which weighed 150kg presented a diaphyseal multifragmentar wedge fracture of right MtIII which was treated with transcortical pins and cast, associated with intralesional application of platelet rich plasma (PRP). After two years of surgery, the animal initiated a training program for racing, and six months later, the patient ran its first official match. The choice of therapeutic methods for treating fractures in horses should be one that provides an earlier repair and minor possibility of complications. Thus, the therapy association which was adopted was considered favorable, since allowed full reestablishment of locomotion of the patient and made possible its return to race.

Avaliação da tenacidade à fratura de diferentes sistemas cerâmicos

Although ceramics present high compressive strength, they are brittle materials due to their low tensile strength so they have lower capacity to absorb shocks. This study evaluated the fracture toughness of different ceramic systems, which refers to the ability of a friable material to absorb defformation energy. Three ceramic systems were investigated. Ten cylindrical samples (5,0mm x 3,0mm), were obtained from each ceramic material as follows: G1- 10 samples of Vitadur Alpha (Vita-Zahnfabrik); G2- 10 samples of IPS Empress2 (Ivoclar-Vivadent); G3- 10 samples of In-Ceram Alumina (Vita-Zahnfabrik). Fracture toughness values were collected upon indentation tests that were performed under a heavy load. A microhardness tester (Digital Microhardness Tester FM) utilized a 500gf load cell during 10seconds to perform four impressions on each sample. Statistically significant results were observed (ANOVA and Kruskal-Wallis tests). In-Ceram Alumina presented the highest median toughness values (2,96N/m3/2), followed by Vitadur Alpha (2,08N/m3/2) and IPS Empress2 (1,05N/m3/2). It may be concluded that different ceramic systems present distinct fracture toughness values, thus In-Ceram is capable of absorbing superior stress when compared to Vitadur Alpha and IPS Empress2.