802 resultados para Juntas adesivas
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This work analyses the chapter 35, book I, of the agricultural treatise Opus agriculturæ, written by Rutilius Taurus Aemilianus Palladius (V C.E.). In that chapter the author presents some recipes, called remedia, to protect the farm and the garden against weeds and weather phenomena, as blight and fogs. The magical practices are identified according to both the fundamental principles of magic (similarity, contiguity, contrariety), which rule magical thought, and some elements of magical symbology. As the author seems not to distinguish magic and science, for he brings together both kinds of recipes, the analysis of some remedia emphasizes a specific study on the materials and substances employed in those recipes and their value in Science today. This leads to the discussions of how magical thought works, what are the limits (if they actually exist) between Magic and Science and between Magic and Religion. This work covers the subjects above and it has the following pourposes: demonstrate the characteristics that authorize the remedia described by Palladius to be classified as folk magic; identify the relations between this kind of practice with more complex forms of magic, as with religion, with science; demonstrate the contribution of the folk magic in ancient Rome farming for the formulation of more apropriated criteria of evaluating magic in comparison to religious and scientific thought.
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On the grounds of the great advances achieved over recent years, the process HF/ERW (High-Frequency/Electric Resistance Welding)welded pipe have played an active role in the oil and gas industry for deep water applications, at high and extremely low temperatures, under high pressure and in highly corrosive environments, gradually replacing manufactured pipes by other processes. However, studies have shown that defects in the welded joints are a the leading causes of pipelines failures, which has required the determination of toughness values in this region, in compliance with the strict recommendations of the codes and standards with manufacturers and construction companies, on the oil and gas sector. As part of the validation process required toughness values, this research project focuses on a microstructural analysis in HF / ERW tubes microalloyed, steel grade API 5CT N80, designed to explore oil and gas in deep waters, the subject of strategic relevance to the country because of the recent discoveries in the Santos mega fields: Tupi and Libra (pre-salt). In this scientific work will be presented and discussed the results of mechanical tensile and Charpy, a few CTOD tests curves (showing the trend of toughness values to be obtained), and the microstructures of the base material obtained by optical microscopy, with special emphasis on the formation of non-metallic inclusions in the welded joint
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Pós-graduação em Odontologia Restauradora - ICT
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In contemporary industrial, welding processes are widely used, this is the most important process of joining metals used industrially. The welding can be used to build simple structures, like doors and gates for instance, in the same way can be used in situations of high responsibility, such as the nuclear industry and oil industry. Dissimilar welding is a case of welded joints, is characterized by the junction between different materials, for this case, stainless steel and carbon steel that are widely used in steam lines, power plants, nuclear reactors, petrochemical plants. Because their different mechanical and corrosive properties, the join, stainless steel with carbon steel, not only meets environmental requirements and also reduces cost. By using penetrating liquid tests, macrograph, hardness and tensile test was compared the possibility of replacing the current use of 309 rods as filler metal in dissimilar welding between carbon steel and stainless steel by add-on material carbon steel essentially, in this case E7018 coated electrode was used, but without the coating. After analysis of the results and for comparison, was proposed with some certainty that it is possible to replace the addition of materials, thus leading economy in this process widely used in the modern industry
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This work focuses on a study on the fatigue behavior of a microalloyed steel API 5L X70, used in pipes lines to transport oil and gas. These types of steels have excellent mechanical resistance values and ductility and therefore increased their study driven by increased demand for oil and especially natural gas, which consequently raises the need to build new pipelines to transport these products. The oil extraction units, composed of the risers (pipelines connecting the oil well to the ship), are dimensioned to remain installed for periods of 20 to 30 years in the marine environment, a hostile environment for high pressure, corrosion, low temperatures and the stresses caused by the movement of water and tides. For analysis, the S-N (stress versus number of cycles) curves were obtained from data collected from bodies-of-proof cylindrical longitudinal, transverse and that one removed from the weld area of the pipe, tested in accordance with ASTM E466. Tensile tests were performed for characterizing the mechanical properties of the samples and welded joints, concluded that the values meet the specifications of the standard API 5L. To characterize microstructural material, also metallographic analysis was made of regions of the base metal and the HAZ. The results of fatigue tests demonstrated a higher life for the specimens removed from the longitudinal direction the pipe, followed by those in the transverse direction and, finally, the welded joint. The origins of the fatigue cracks were determined by scanning electron microscopy (SEM)
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The success rate of resin-bonded fixed partial dentures is directly related to the adhesive system and the tooth preparation design for good retention. These resin-bonded bridges represent a prosthodontic alternative, based on their costeffectiveness, conservative techniques, and ease of laboratory manufacturing. Through a thorough review of the literature, this study aimed to report on cavity designs, types of materials used, and the advantages and disadvantages of the resin-bonded fixed partial denture. One of significant advantages of the resin-bonded fixed partial dentures is the conservation of the tooth structure, whereas its main disadvantage includes aesthetic limitations, given that the alloy may in fact be visible. Preparation design, cement type, and casting alloy type, as well as surface treatment, are among the factors that influence the longevity of resin-bonded fixed partial dentures. Treatments with resin-bonded fixed partial dentures present a bright outlook regarding the conservation of tooth structures, as well as a high level of success.
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Atualmente, os pacientes buscam cada vez mais estética, e o profissional deve ser capaz de suprir a necessidade da demanda atual. Para isso, os profissionais devem estar atentos a não somente devolver funcionalidade a seus procedimentos restauradores, mas acima de tudo buscar excelência estética. Entre esses procedimentos, as restaurações adesivas diretas são capazes de mimetizar o que é artificial, tornando as restaurações naturais. Esse artigo tem o objetivo de expor uma sequência clínica, de certa maneira simplificada, em que o profissional conseguiu uma restauração altamente estética.
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Pós-graduação em Agronomia (Horticultura) - FCA
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Pós-graduação em Odontologia Restauradora - ICT
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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This study evaluated the influence of different forms of heat treatment on a pre-hydrolyzed silane to improve the adhesion of phosphate monomer-based (MDP) resin cement to glass ceramic. Resin and feldspathic ceramic blocks (n=48, n=6 for bond test, n=2 for microscopy) were randomly divided into 6 groups and subject to surface treatments: G1: Hydrofluoric acid (HF) 9.6% for 20 s + Silane + MDP resin cement (Panavia F); G2: HF 9.6% for 20 s + Silane + Heat Treatment (oven) + Panavia F; G3: Silane + Heat Treatment (oven) + Panavia F; G4: HF 9.6% for 20 s + Silane + Heat Treatment (hot air) + Panavia F; G5: Silane + Heat Treatment (hot air) + Panavia F; G6: Silane + Panavia F. Microtensile bond strength (MTBS) test was performed using a universal testing machine (1 mm/min). After debonding, the substrate and adherent surfaces were analyzed using stereomicroscope and scanning electron microscope (SEM) to categorize the failure types. Data were analyzed statistically using two-way test ANOVA and Tukey's test (=0.05). Heat treatment of the silane containing MDP, with prior etching with HF (G2: 13.15 ± 0.89a; G4: 12.58 ± 1.03a) presented significantly higher bond strength values than the control group (G1: 9.16 ± 0.64b). The groups without prior etching (G3: 10.47 ± 0.70b; G5: 9.47 ± 0.32b) showed statistically similar bond strength values between them and the control group (G1). The silane application without prior etching and heat treatment resulted in the lowest mean bond strength (G6: 8.05 ± 0.37c). SEM analysis showed predominantly adhesive failures and EDS analysis showed common elements of spectra (Si, Na, Al, K, O, C) characterizing the microstructure of the glass-ceramic studied. Heat treatment of the pre-hydrolyzed silane containing MDP in an oven at 100 °C for 2 min or with hot air application at 50 ± 5 ºC for 1 min, was effective in increasing the bond strength values between the ceramic and resin cement containing MDP.
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O profissional de educação física nos dias atuais deve ter amplo conhecimento sobre diversos assuntos relacionados à prevenção e manutenção da saúde de modo que este poderá atuar diretamente na melhora e reeducação da qualidade de vida de diferentes estados físicos e emocionais das pessoas em que irá trabalhar. O consumo abusivo de drogas ilícitas no século XXI, trás consequências emocionais e físicas, as dependências econômicas e de saúde geradas pelo seu consumo e propaga-se que, quando não tratadas adequadamente podem gerar um ciclo caótico de complicações, vindo a estabelecer problema real para a saúde pública mundial. O presente trabalho tem por objetivo enfatizar por meio da revisão de literatura os efeitos benéficos, tanto psicológicos como fisiológicos, que os programas de atividade física regular exerce no processo de cuidado e/ou zelo do dependente químico em meio ao tratamento. Constatou-se que a atividade física nos cuidados e/ou zelo do dependente proporciona inúmeros benefícios à saúde, além de contribuição fisiológica como desintoxicação, diminuição da frequência cardíaca de repouso e pressão arterial, melhorar a vascularização, diminuir a fadiga central, liberação do hormônio do prazer (endorfina) e as capacidades funcionais musculoesqueléticas. O exercício também é de fundamental importância para resgatar aspectos psicológicos como controle da ansiedade, depressão, alivio do estresse, melhora da autoimagem, autoestima, confiança e disciplina para seguir o tratamento e futuramente sua vida, e por fim possibilitou, ainda, entender as relações entre as funções fisiológicas e psicológicas do homem, de modo a deixar explícito que ambas caminham juntas e uma equipe multidisciplinar contando com psicólogos, nutricionista e profissionais de educação física se faz necessário, visto que eles trabalham em equipe levando em consideração as especificidades de cada...
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Pós-graduação em Odontologia Restauradora - ICT
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)