The composite formed by 316L steel with 10% of Sr1,8Y0,2CrReO6 (SYCRO) double perovskite was successfully sintered using Top Down nanotechnology associated with powder metallurgy. SEM images showed that the SYCRO nanoparticles were deposited on the steel surface homogeneously. The scattering spectra of the images confirmed the presence of the Sr and Re elements scattered homogeneously on the surface of the composite, which corroborates the images observed by SEM. X-ray microtomography showed a solid build, with few pores and cracks, and a 3D distribution of the main components. X-ray diffraction measurements showed that SYCRO particles were embedded in the 316L steel matrix. Magnetic susceptibility a.c. showed that the composite has ferromagnetism and Tc close to that found in the literature for the ceramic composite Sr1,8Y0,2CrReO6, which certifies that the sintering of the composite was obtained successfully.

Aureliano Junior, R. T. Production and characterization of nodular cast irons alloyed with niobium subjected to boronizing and thermoreactive thermochemical treatments.

The Brazilian Caatinga houses a number of cacti species, which are considered endangered due to human influence. Two of them, Melocactus zehntneri Braun ex Ritter f. and Cereus gounellei Luetzelb ex Schum k., are endemic of the Brazilian Caatinga. Cryopreservation can provide a means for long-term preservation of endangered plant material. The aim of this study was to evaluate the efficiency of cryoprotectants for the cryopreservation of seeds from these two ­species. The treatments consisted of immersing seeds in different cryoprotectant solutions and vitrification solutions before storage in liquid nitrogen (NL) at -196 °C, as follows: T1- Control: no cryoprotectants; T2- PVS2 (10 min), T3-  PVS2 + phloroglucinol 1% (10 min), T4- PVS2 (10 min) + Supercool 1%; T5- PVS2 + phloroglucinol 1% (10 min) + Supercool 1%. Seed germination was evaluated after cryopreservation. The experimental design was completely randomized with five treatments and five replicates per treatment. Seed moisture at the beginning of the experiment was 6.2% for M. zehntneri and 7.8% for C. gounellei. There were no statistically significant differences for the seed germination percentage among the different treatments. Therefore, we concluded that seed of these two cacti species can be cryopreserved directly without the need for cryoprotectant solutions.

Dedico este trabalho ao meu tio José Pereira (in memorian) e minha tia Sonia, aos meus pais Ricardo e Dalva, a minha irmã Lais e a todos os demais familiares, pela paciência, compreensão e pela força dada durante todo esse período de estudo. AGRADECIMENTOSAgradeço primeiramente a DEUS por me dar sabedoria e força para enfrentar as batalhas do dia-a-dia.Ao professor e Orientador José Ricardo Tarpani, pela orientação, atenção e pelos ensinamentos passados ao longo desse período de mestrado.Ao professor Rudimar Riva e a todos os funcionários do IEAv pela colaboração junto a esse projeto de pesquisa.A todos os professores do SMM e externos, pelos ensinamentos passados, sejam eles durante uma disciplina, ou através de uma simples conversa.Aos técnicos do departamento de Engenharia Materiais USP -São Carlos: Alberto, João, Pedro, Eliezer (Tico), Douglas, Ricardo e Wagner pelas dicas e por estarem sempre prontos a ajudar.À Escola de Engenharia de São Carlos, pela oportunidade de realização do curso de mestrado.À CAPES, pela concessão da bolsa de mestrado e pelo apoio financeiro para a realização desta pesquisa.Aos amigos do grupo de compósito pelo companheirismo, de todos os dias. À todos os pós graduando e alunos, em especial: