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Microestrutura e propriedades mecânicas da liga AA6061 processada por deformação plástica severa em temperatura criogênica
(Universidade Federal de São Carlos, 2017-08-08) Magalhães, Danielle Cristina Camilo; Kliauga, Andrea Madeira; https://lattes.cnpq.br/3527528295399928; Sordi, Vitor Luiz; https://lattes.cnpq.br/8364164402481940; https://lattes.cnpq.br/5486724956564584
The present work aimed two fronts: to characterize the mechanical behavior of the AA6061 alloy at cryogenic temperature, and to study the microstructural and properties evolution after cryogenic severe plastic deformation. Samples of AA6061 alloy were solution heat-treated and processed by conventional rolling, asymmetric rolling and equal-channel angular pressing (ECAP), both at room temperature and cryogenic temperature. After processing, such samples were treated for precipitation at 25 °C and at 100 °C, for different times. On the cryogenic mechanical behavior it was observed the suppression of the dynamic strain aging, which also allowed the ECAP processing without cracking. Uniform and total elongation and mechanical strength were always higher at -196 °C than at room temperature. The strain-rate sensitivity, despite having low values, becomes positive for cryogenic deformation, directly affecting the deformation capacity. Regardless of the processing route employed, a saturation of the hardness around 125 HV has been seen. The microstructures after cryogenic ECAP were very refined in relation to the starting material (average grain size up to 500 nm). In addition, it was observed a homogeneous strains distribution after cryogenic processing, with detection of several new fine grains from grain boundaries, which suggests recrystallization. The tensile tests results, after cryogenic processing in combination with artificial aging at 100 °C (48 hours), indicated an increase in uniform elongation. Regarding mechanical strength, the highest values were observed for extrusion at room temperature combined with artificial aging. In addition, there was to some static recovery during artificial aging, especially for cryogenic processing, which generates thermodynamically unstable microstructures. The density of dislocations, in fact, decreases with the prolongation of artificial aging time. Thus, the present study was based on a study of the cryogenic mechanical behavior of the AA6061 alloy, as well as the possibility of processing by cryogenic severe deformation.
GromaXy: uma ferramenta para integração do Galaxy com o GROMACS
(Universidade Federal de São Carlos, 2017-08-08) Souza, Alfredo Guilherme da Silva; Trevelin, Luis Carlos; https://lattes.cnpq.br/5082419783043736; https://lattes.cnpq.br/0459570418915149
Considering the significant advances in biomolecular researches, the raise of various limitations is predicted. Thereby, reinforcing the link between science and technology, by introducing the new and effective development tools which can be used in a variety of scientific studies (i.e. Molecular Dynamics methods for drug discovery), becomes necessary. This method enables the realization of simulations in biomolecular studies in which atoms' behavior can be observed during a specific period of time. In the state of art various researches related to development of tools, whose main goal is facilitating Molecular Dynamics studies, are encountered. The GROMACS is one of these tools that is known as an open-source tool that has been used in lots of research projects. Due to the complexity of manipulating the GROMACS, the current study presents a new tool called GromaXy, which aims at providing a new interaction way with GROMACS, by introducing a new graphical interface which is much more convenient than the GROMACS command line. In addition to providing a new interaction way with GROMACS, the GromaXy also offers an adoptation of Atom Validation, which is another tool that has been developed in one of the previous studies. Atom Validation identifies the absent atoms in protein structure and show the to the user in form of a list. GromaXy was developed using a well-known framework in bioinformatic area called Galaxy. This framework was preferred due to its simple environment, the ability of sharing the work history and the history of realized experiments, enabling the high-level storage of data related to the trajectory of simulation process. The GromaXy was chosen as an adequate name which presents the join of Galaxy and GROMACS.