Paulo Atsushi Suzuki

Neste trabalho investigamos as trajetórias adotadas por uma professora de matemática que assiste particularmente um aluno com Deficiência Intelectual (DI) o qual apresentou progressos significativos em interpretação de texto matemático, raciocínio lógico e cálculo no decorrer de 3 anos. O objetivo foi o de compreender como a docente produziu a interação entre professor, aluno e objeto de ensino, de modo que a prática pedagógica fosse significativa e efetiva. Para tanto, utilizamos a Fenomenologia para descrever o processo interativo entre professora e aluno, bem como as trajetórias adotadas pela professora em seu fazer pedagógico. Os dados foram coletados em diários de campo que descrevem o atendimento particular e mediante a realização de entrevistas com os parentes e profissionais da escola regular em que o aluno está matriculado. A análise dos dados foi feita em função dos existenciais propostos na filosofia existencialista de Heidegger.

To solve chipping of veneer porcelain in zirconia dental prosthesis it has been studied different cooling rates in firing schedules to control residual stresses generated by differences in thermal properties between the ceramics. However, cooling rates may affect the porcelain, irrespectively of interaction with zirconia. This study analyzed the effect of cooling rate on the three-point flexural strength (FS), residual stress, Vickers hardness (VH) and V-notch fracture toughness (SEVNB) on a feldspathic porcelain (Vita VM9) indicated for covering zirconia. Bar-shaped specimens were sintered according manufacturer's schedule firing and cooled at different rates (slow, normal or fast). Specimens were tested for FS (n=30), VH (n=15) and SEVNB tests (n=15). Weibull analysis were performed from FS values to measure reliability and probability of failure (PF). One-way ANOVA was significant for VH (p<0.001), and Tukey's test showed that slow cooling led to higher values. There was no significant difference for FS (p=0.654) and SEVNB (p=0.734). Fast cooling led to the lowest PF, but cooling rate factor was not significant for Weibull modulus. All cooling group showed residual tensile stress (MPa): Slow = 34.81; Normal = 27.04; Fast = 18,98. It was concluded that cooling rate produce minor changes in the porcelain properties.

Multicomponent Ti₆Si₂B-based alloys are potentially attractive for structural applications due to the low Ti₆Si₂B crystallographic anisotropy, and their oxidation resistance are higher than the Ti₅Si₃-based alloys. There is a limited amount of information on effect of alloying on stability of Ti₆Si₂B. The present work reports on the structural evaluation during ball milling and subsequent sintering of Ti-2Cr-22Si-11B and Ti-7Cr-22Si-11B (at-%) powders. The milling process was carried out in a planetary Fritsch P-5 ball mill under Ar atmosphere using hardened steel balls (19 mm diameter), stainless steel vials (225 mL), rotary speed of 300 rpm, and a ball-to-powder weight ratio of 10:1. Samples were collected after different milling times: 20, 60, 180, 300, 420 and 600 min. Addicional wet milling (isopropyl alcohol) for 20 more minutes was adopted to increase the yield powder into the vials. Following, the powders milled for 620 min were uniaxially compacted (20 MPa) in order to obtain cilinder green bodies with 10 mm diameter and subsequently sintered under vacuum at 1100°C for 240 min. The milled powders were characterized by X-ray diffraction, and scanning electron microscopy. The chromium addition have contributed to form a large amount of Ti₆Si₂B in the mechanically alloyed and sintered Ti-2Cr-22Si-11B and Ti-7Cr-22Si-11B alloys.