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Trincamento induzido por hidrogênio em aços inoxidáveis supermartensíticos modificados pela ação de boro para aplicação em exploração de petróleo em águas profundas
(Universidade Federal de São Carlos, 2015-09-21) Bertoldi, Daniel Brito; Silva, Paulo Sérgio Carvalho Pereira da; https://lattes.cnpq.br/4783514460488161; Ishikawa, Tomaz Toshimi; https://lattes.cnpq.br/5726055117451807; https://lattes.cnpq.br/1136545754858954
The oil exploitation and production in deep water involves drilling risers with over 7 km deep. In this condition, the environments found in such wells are too adverse, acting under the exploration and production equipment, high pressures, low temperatures, severe conditions of corrosion, wear and enabling environments to hydrogen formation in the presence of H2S. Stainless steels, such as supermartensitic, duplex and super duplex have corrosion resistance and mechanical properties suitable for use in pipes in oil exploitation; however, such materials have low wear resistance. Recent studies in DEMa-UFSCar shown promising results related to supermartensitic stainless steel with boron addition, promoting the borides formation which, in turn, increases the wear resistance of these materials. In this situation, no studies have yet been performed in relation to another critical requirement in this type of request: the hydrogen permeation. It is known that hydrogen in its atomic form, when it diffuses through the steel is deleterious to the mechanical properties. Thus, a more detailed study is needed to assess the influence of this element in such properties, analyzing his performance in microstructural character. The materials produced were characterized by techniques with X-ray diffraction (XRD), optical microscopy (OM) and scanning electron microscopy (SEM). After this stage, tensile specimens were hydrogenated by electrolytic technique and tested with low strain rate. The results were compared with the same material without a prior hydrogenation and showed a major influence of the microstructure in relation to the reduction of the absolute value of some important mechanical properties.
Síntese e caracterização de filmes finos de TiNb sobre o aço AISI 316L para aplicações biomédicas
(Universidade Federal de São Carlos, 2015-09-21) Cruz, Ernesto David Gonzalez; Afonso, Conrado Ramos Moreira; https://lattes.cnpq.br/2176215981291453; Nascente, Pedro Augusto de Paula; https://lattes.cnpq.br/1387043320265189; https://lattes.cnpq.br/4330577960329954
Titanium and its alloys have been widely used in biomedical devices and components. The commercially pure titanium and Ti-6Al-4V (Ti64) are the biomaterials most widely used for implants, due to its characteristics regarding corrosion resistance, biocompatibility and commercial production. However, in the case of the Ti64 alloy, aluminum and vanadium present problems associated with cytotoxic effects in tissues and adverse reactions such as Alzheimer's disease and other neuropathies. The β type Ti alloys used in orthopedic devices have excellent properties such as low density, high mechanical strength and outstanding corrosion resistance, besides being biocompatible. The β phase in Ti alloys is obtained by adding alloy elements such as Nb, Ta, Zr and Mo. The coatings in form of thin films made by magnetron sputtering - MS have been successfully employed for the surface treatment of metallic biomaterials for ‘applications in the medical industry, with the advantage that low dimensionality coating does not alter the structural properties of the prosthesis to be implanted, thereby allowing improvement of their surface properties and therefore the use in the human body. A new class of Ti alloys employs niobium as a stabilizer of the β phase. The Ti-Nb binary alloys are promising candidates for biomedical applications. Therefore, an interesting option to adjust the surface feature is the thin film technology. Thus, in this dissertation, nanostructured thin films were produced by sputtering on the surface of stainless steel AISI 316L, with the purpose of analyzing the influence of niobium content on the behavior of the films. The produced films were mechanically, morphologically, crystallographically, chemically and electrochemically characterized, presenting the Ti-β phase for all the concentrations along with good mechanical properties and corrosion resistance for its potential use in the manufacture of medical implantation devices.
Programa Vamos Cuidar do Brasil com Escolas Sustentáveis : análise de uma experiência na Escola Estadual Antonio Padilha no munícipio de Sorocaba-SP
(Universidade Federal de São Carlos, 2015-09-21) Freitas, Maria Estela Maciel; Freitas, Denise de; https://lattes.cnpq.br/3330976062026878; https://lattes.cnpq.br/4535850065796436
Considering that the construction of sustainable social practices are central goals to guide the education of citizens in any learning context the Ministry of Education (MEC) has prepared the Progran “Let’s take care of Brazil” with sustainable schools which provides guidelines for the development of environmental education practices in schools. To participate in this program the school must present an ongoing project, addressing social and environmental issues in which the student is the subject of their learning in order to reach a personal, collective, conscious and critical training. Thus, among the objectives of this research are highlighted as follows: describe and analyze the development of the Program proposed by Ministry of Education (MEC) “Let’s take care of Brazil with sustainable schools / COM –VIDA” in school E.E. Antonio Padilha, located in Sorocaba-SP between the years 2013 and 2014, describe and analyze the practices developed by COM-VIDA and identify practices related to sustainability of those involved in the project. The methodology that leads this research is the study of qualitative case, as the case study focuses on a particular event revealing its peculiarities. For data collection were used different methods such as document analysis, participant observation, questionnaires and semi-structured interview. The Project began timidly in 2013 with the realization of practices that motivated students to participate in the IV National Children and Youth Conference for the Environment and as a result, we have the first group of students who started actions of environmental education at school. In 2014, such actions kept leading the construction of the COM-VIDA, a discussion space on environmental issues, providing carrying out actions to improve the quality of life and sustainability in the school environment. The implementation of the program and the construction of the COM-VIDA, provided to students of elementary school (6º to 9º years) practical experiences in environmental education focused on sustainability. The workshops COM-VIDA, guided in education for sustainability, the students had the opportunity to identify, discuss and propose solutions to local environmental and social problems. Among these activities are the awareness Project “Sustainability without being cliché” about the waste and proper disposal of garbage with the implementation of selective collection in our school, and growing food in the school garden. All activities were designed by the students themselves are the main protagonists in this process. Through these experiences for building theory knowledge about sustainability, it has been built their environmental identities. The move COM-VIDA has made the theme enter therein in the school environment both by students and by the managment staff causing small changes in individual and collective attitudes of the entire school community.
Síntese e propriedades de sílicas híbridas contendo surfactantes catiônicos
(Universidade Federal de São Carlos, 2015-09-21) Campos, Ana Flavia Pinheiro de; Cardoso, Dilson; https://lattes.cnpq.br/2462847535959232; https://lattes.cnpq.br/7465177122348197
The control of pore geometry and pore diameter of silica mesoporous materials is necessary for application of these materials, mainly in industrial process that depends on the shape selectivity. This way, considerable efforts have been devoted to control pore structure of these materials. In this study it has been found the influence of cetyltrialkylammonium and alkyltripropylammonium (CnPr3Br, n = 14-22) surfactants in the formation and properties of mesoporous silicas and subsequently microporous silicas. Regarding the mesoporous silicas synthesized through cetyltrialkylammonium surfactants, it was observed that the silicas pore size increased and the structural ordering decreased as the head group of surfactants increased. In contrast, the increase of lkyltripropylammonium tail resulted in silicas with larger porous diameter and structural ordering. The mesoporous silica with the largest pore diameter (3,60 nm), synthesized with C22Pr3Br surfactant exhibited narrow pore-diameter distribution and a hexagonal organization characteristic of MCM-41 silica. The performance of alkyltripropylammonium surfactant as zeolitic structure directing agents was also investigated. The results showed the formation of a physical mixture between MFI and magadiite structures under different hydrothermal treatment temperatures. Only after addition of tetrapropylammonium cations to reaction mixture containing alkyltripropylammonium cations it was possible to obtain pure MFI structure. However, the presence of alkyltripropylammonium cations had strong influence on the crystals growth and consequently in the form of zeolite crystals obtained.