24 documents found, page 1 of 3

Online communication and assessment practices during the Covid Pandemic: a stud...

This proposal is part of an ongoing research and presents the results on the perceptions and pedagogical practices experienced by students from various higher education degrees in Portuguese higher education institutions, during the period of social confinement determined by the Portuguese Government, due to the COVID-19 pandemic. The main objective of the general research was to understand how Higher Education...

Tecnologias e estratégias de comunicação online durante a pandemia covid-19: o ...

The suspension of classroom classes from March 2020, determined by the Portuguese government in response to the CoViD-19 pandemic, imposed on educational institutions an unprecedented urgency of innovative pedagogical practices facilitated by technology. Among the many challenges, teachers had to adapt and reinvent their teaching strategies and methodologies. Having additional difficulties such as the lack of a...

Atractocerus Brasiliensis Lep. & Serv. (Coleoptera: Lymexylidae): Aspectos Repr...

Surface modification of a polyethersulfone microfiltration membrane with graphe...

Polyethersulfone microfiltration membranes (mPES) were modified with polyethilenimine (PEI) and graphene oxide (GO) by layer-by-layer self-assembly method via electrostatic interaction using a pressurized filtration system. The high positively charge of PEI allowed it to be easily assembled on the polyethersulfone substrate, and also to receive the negative layer of GO. Several techniques were applied to charac...

Oxypetalum banksii subsp. banksii: a taxon of Asclepiadaceae with an extragynoe...

The floral morphology of seven Oxypetalum species and, in particular, the spatial relationship between the five stigmatic chambers and two separate ovaries of their flowers with respect to transmission of the pollen tube are studied. In all species, except O. banksii subsp. banksii, floral morphology is similar to that in other Asclepiadeae, and the flowers pollinated with one pollinium develop only one follicl...

Microstructure and strength of γ-TiAl alloy/Inconel 718 brazed Joints

Intermetallics and superalloys brazing development is a current topic owing the extending use of these alloys in industrial applications. In this work a γ-TiAl alloy was joined to Inconel 718 by active metal brazing, using Incusil-ABA as filler. Joining was performed at 730 °C, 830 °C and 930 °C, with a 10 min dwelling time. The interfaces were characterized by Scanning Electron Microscopy (SEM), Energy Dispers...

Brazing Ti-47Al-2Cr-2Nb to Inconel 718 with different filler alloys: microstruc...

Vacuum brazing of γ-TiAl alloy (Ti-47Al-2Cr-2Nb, at.%) to Inconel 718 (53Ni-19Fe-19Cr-5Nb-3Mo-1Ti wt.%) using Incusil-ABA (Ag-27.25Cu-12.5In-l.25Ti, wt.%), Nicusil-3 (Ag-28.lCu-0.75Ni, wt.%) and Tini 67 (Ti-33Ni, wt.%) as filler alloys was investigated. The lowest temperatures at which joining was successfully accomplished were 730, 810 and 1200°C for brazing with Incusil-ABA, Nicusil-3 and Tini 67, respectivel...

Strain path and work-hardening behavior of brass

http://www.sciencedirect.com/science/article/B6TXD-4VCH6XN-2/2/f2fdcdb8e9296ed402996e926d4803b4

Diffusion brazing of a gamma-TiAl Alloy Using Tini 67: microstructural evolutio...

A detail study focussing the microstructural evolution of the interfacial zone in the course of the processing of Ti-47Al-2Cr-2Nb joints using Tini 67 as filler alloy was carried out in this investigation. Experiments, aiming the understanding of the mechanisms that promote the melting of the braze alloy, were performed below the solidus temperature of the filler, at 750 and 900 degrees C. Diffusion brazed samp...

Solid-state diffusion bonding of gamma-TiAl alloys using Ti/Al thin films as in...

Alternating nanometric layers of titanium and aluminium were used as filler material to promote joining between titanium aluminide samples. The improved diffusivity of these nanometric layers is thought to overcome the difficulties in solid-state joining of titanium aluminides without producing chemical discontinuities at the interface. In this study, a thin multilayer (alternating titanium and aluminium layers...