Active Metal Brazing of Machinable Aluminum Nitride-Based Ceramic to Stainless Steel

Shapal!-M machinable AlN-based ceramic and AISI 304 stainless steel were joined by active metal brazing, at 750, 800, and 850 !C, with a dwell stage of 10 min at the processing temperature, using a 59Ag- 27.25Cu-12.5In-1.25Ti (wt.%) filler foil. The influences of temperature on the microstructural features of brazed interfaces and on the shear strength of joints were assessed. The interfacial microstructures were analyzed by scanning electron microscopy (SEM), and the composition of the phases detected at the interfaces was evaluated by energy dispersive X-ray spectroscopy (EDS). The fracture surfaces of joints were analyzed by SEM, EDS, and GIXRD (Grazing Incidence X-Ray Diffraction). Reaction between the liquid braze and both base materials led to the formation of a Ti-rich layer, adjacent to each base material. Between the Ti-rich layers, the interfaces consist of a (Ag) solid-solution matrix, where coarse (Cu) particles and either Cu-In or Cu-In-Ti and Cu-Ti intermetallics phases are dispersed. The stronger joints, with shear strength of 220±32 MPa, were produced after brazing at 800 !C. Fracture of joints occurred preferentially not only through the ceramic sample but also across the adjoining TiN layer, independent of the brazing temperature

Monitoring process of the re-construction of an ancient structure: the Baluarte do Cavaleiro

The Baluarte do Cavaleiro is part of the stone masonry wall system existing in the city of Chaves of Portugal and it is a construction dated from the XVII century. The Baluarte do Cavaleiro is formed by three walls (North-East, NE; South-East, SE; South-West, SW) and by two junction elements (designated here by cunhais). The SE wall has suffered two collapses recently. The main objective of this research work is to describe the monitoring process adopted to control the stability of the Baluarte do Cavaleiro and the adjacent constructions that could be affected during the last rebuilding process of this wall. Taking into account that this rebuilding process included the total removal of this wall, it was also possible to identify the real geometry of the cross section of the wall, its building solution and the type of the sustained soil. It was also possible to contribute for a better understanding of the structural behaviour of this kind of stone masonry construction

Microstructure, mechanical properties and corrosion behaviour of Ti6Al4V/Al2O3 joints brazed with TiCuNi filler

Ti6Al4V and Al2O3 were successfully vacuum brazed at 980 °C using TiCuNi filler foil. The microstructure and the chemical composition of the interface were analysed by SEM (scanning electron microscopy) and EDS (energy dispersive spectros- copy), respectively. The hardness profile across the interface and the mechanical strength of joints were assessed by Vickers microhardness tests and shear tests, respectively. The fracture surfaces were analysed by SEM, EDS and XRD (X-ray dif- fraction). The corrosion behaviour of joints was evaluated by OCP (open circuit potential), potentiodynamic polarisation tests and EIS (electrochemical impedance spectroscopy). Brazing produced a layered interface, free of pores and cracks, essentially composed of α-Ti, Ti2(Cu,Ni) and TixOy. The shear strength of joints was 168 ± 13 MPa, and fracture occurred partially through the hardest zone of the interface (1261 HV0.01.), located in the vicinity of the Al2O3 sample, and partially through the ceramic sample. The brazed joint did not significantly affect the corrosion behaviour of Ti6Al4V.This work was supported by the Portuguese Foundation for Science and Technology (FCT), Portugal, under PTDC/CTM-CTM/31579/2017—POCI-01–0145-FEDER – 031579 – funded by FEDER funds through COMPETE2020—Programa Operacional Competitividade e Internacionalização (POCI) and by national funds (PIDDAC) through FCT/MCTES

Tumor de Buschke-Lowenstein

Introduction: Giant condyloma acuminatum belongs to a spectrum of diseases with malignant degeneration. Clinically, it presents as exophytic, fungating masses, sometimes with a cauliflower-like morphology. Case presentation: We present a case of a 32-year-old female patient with a 180x95x80mm exophytic mass of the vulvar region suggestive of Buschke-Lowenstein Tumour. Treatment included wide local excision with electrosurgery and CO2 vaporization of recurrent focal lesions. Histopathological analysis confirmed the expected diagnosis. Surgery went without complications and the patient is lesion-free at the 12th month of follow-up. Conclusion: There is a lack of consistent trials regarding optimal treatment of BLT. Surgery, when feasible, remains the mainstay of treatment. It allows quick lesion size reduction, with fewer side effects and more rapid return to daily living activities, when compared to other treatment options

Single strand conformation polymorphism (SSCP) detection in six genes in the Portuguese indigenous sheep breed "Churra da Terra Quente"

Evaluation of the genetic diversity for six genes in forty animals of the Portuguese indigenous sheep breed (Ovis aries) “Churra da Terra Quente” was done. A non-radioactive method to allow single-strand conformation polymorphism (SSCP) detection was optimised, starting from genomic DNAand PCR amplification of seven fragments: exon 1 of the a-lactalbumin gene; exons 10 and 11 of the as1-casein gene; exon 7 of the b-casein gene; exon 4 of the k-casein gene; exons 4 and 5 of the growth hormone gene and exon 6 of the growth hormone receptor gene. Polymorphisms were detected in five of the PCR products. Only k-casein and growth hormone receptor were monomorphic. a-lactalbumin and as1-casein exons showed three conformational patterns, b-casein and growth hormone exon 4 showed two electrophoretic patterns and growth hormone exon 5 showed five conformational patterns. These data provide evidence that “Churra da Terra Quente” has a high genetic variability, which opens interesting prospects for future selection programs and also for preservation strategies. Also, our data show that PCR-SSCP is an appropriate tool for evaluating genetic variability

O conhecimento tradicional sobre ecologia e extração do óleo de andiroba nas reservas de desenvolvimento sustentável Mamiraua e Amanã, AM, Amazônia Brasileira.

Por trás do aparato comercial das indústrias de produtos naturais, existe o conhecimento das populações que, tradicionalmente, extraem o óleo de andiroba e encontram dificuldades de acesso ao mercado. O objetivo deste foi identificar o conhecimento tradicional sobre a andiroba e caracterizar o modo de extração dos ribeirinhos das Reservas Mamirauá e Amanã, Amazonas, Brasil. Foram realizadas 30 entrevistas, em 18 comunidades. A maioria dos entrevistados possui ensino fundamental incompleto, a renda familiar é composta pelo extrativismo e bolsas sociais. A extração do óleo de andiroba é realizada prioritariamente para o consumo, embora haja potencial para a comercialização. Os extratores visitam o andirobal uma única vez no ano para coletar as sementes. Não identificam claramente as fases fenológicas, mas, sabem quando é o ?tempo de coletar?, por exemplo. A maioria dos informantes afirma que as andirobeiras frutificam entre novembro e junho e a dispersão acontece entre dezembro e julho, sendo melhor para coletar em maio. Declaram que as sementes são todas iguais, porém dizem ter diferença na madeira: branca ou vermelha.Todos os entrevistados relataram saber extrair o óleo e que esta é uma atividade realizada principalmente pelas mulheres. As etapas são: coleta das sementes, cozimento, secagem, descascamento, preparo da massa e escorrimento do óleo. Estas informações facilitam o manejo da atividade nessas áreas, valorizam o conhecimento tradicional associado e o empoderamento feminino na exploração de óleos de sementes florestais. Podendo alavancar a organização social para a comercialização de um produto amazônico de forma sustentável, mantendo a floresta em pé

Multilayered interface in Ti/Macor (R) machinable glass-ceramic joints

Macor® machinable glass-ceramic and commercially pure (cp.) titanium were joined by active metal brazing, using a 64Ag–34.5Cu–1.5Ti (wt.%) filler alloy. The influence of the brazing temperature and holding stage on the microstructure and hardness profile of the interface, as well as on the shear strength of the joint, were assessed. Brazing was performed in a high vacuum furnace at 850, 890 and 930°C for 10 and 30 min. The reaction between the braze alloy and both materials led to the formation of a multilayered interface. The interfacial microstructure was analysed in a scanning electronic microscope (SEM) and the composition of each reaction layer was investigated by energy dispersive X-ray scans (EDS). The interfacial hardness profile was determined by a series of microhardness tests on each reaction layer. The mechanical strength of the joint was assessed from shear tests conducted at room temperature. Brazing at 850°C with a 10 min holding stage produced stronger joints, with an average shear strength of more than 85% of the glass-ceramic bulk strength

Joining Ti-47Al-2Cr-2Nb with a Ti/(Cu,Ni)/Ti clad-laminated braze alloy

The joining of Ti-47Al-2Cr-2Nb using Ti-15Cu-15Ni (wt.%) as braze alloy was investigated. Experiments were conducted at 980 and 1000ºC for 10 min. The microstructure and the chemical composition of the interfaces were studied by scanning electron microscopy (SEM) and by energy dispersive X-ray spectroscopy (EDS), respectively. For both processing conditions the reaction between the gamma-TiAl alloy and the braze alloy produced layered interfaces, which are essentially composed of apha2-Ti3Al and of Ti-Ni-Cu-Al and Ti-Ni-Cu intermetallic compounds. Microhardness tests showed that all reaction layers are harder than either the gamma or the (alpha2 + gamma) lamellar grains of the intermetallic alloy