Encontrados 15 documentos, a visualizar página 1 de 2
Galvanic Corrosion Behaviour of Ti and Ti6Al4V Coupled to Noble Dental Alloys
Solá, Cristina; Amorim, Armanda; Espías, Ángel; Capelo, Sofia; Fernandes, João; Proença, Luís; Sanchez, Luis; Fonseca, InêsThis study aims to evaluate the electrochemical corrosion behaviour of titanium and Ti6Al4V alloy coupled to the following noble dental alloys: Pontor® 2, Cerapall® 2, V-Gnathos® Plus and Pagalin® 2. The study was conducted in artificial saliva, pH 7.1, at 37 , by linear sweep voltammetry, electrochemical impedance spectroscopy and chronoamperometry.The Rp values of the noble dental alloys varied from 104 to 10...
The corrosion resistance of two non-noble alloys
Capelo, Sofia; Fernandes, JCS; Proença, L; Fonseca, ITENickel-chromium and cobalt-chromium alloys are commonly used for crown and bridge castings. These non-noble dental alloys are much cheaper than noble dental alloys but on the other hand they have disadvantages related to their lower corrosion resistance and corrosion products (released ions), some of them recognized as toxic ions that may cause allergies and other oral pathologies. Therefore it is important to ...
Copper corrosion in soils contaminated with high concentrations of chlorides
Niculita, E.; Ornelas, I.; Capelo, Sofia; Fonseca, I.T.E.The influence of the soil composition on the corrosion resistance of buried metallic structures and the nature of the corrosion products formed are of great importance in many industrial applications, as well as in archaeological studies of metallic finds. Modifications in the soils characteristics can result from agricultural activity, such as fertilization, chemicals accidentally spilled into the soil (acids ...
Galvanic Corrosion of Two Non Noble Dental Alloys
Capelo, Sofia; Proença, L; Fernandes, JCS; Fonseca, ITEThis study aims to evaluate the corrosion resistance of two nonnoble dental alloys, namely, the Wiron®88 (Ni–Cr–Mo) and the Remanium 2000+ (Co–Cr–Mo–W). A noble alloy, the V-Gnathos® Plus (AuPt) previously studied was also considered for the purpose of comparison. The study was conducted in artificial saliva, pH 7.1, at 37 °C, by cyclic and linear sweep voltammetry, electrochemical impedance spectroscopy and ...
Is social coesion affecting heritage landscape perservation and interpretation?
de Mascarenhas, José Manuel; Themudo Barata, Filipe; Capelo, SofiaUsually heritage landscape is seen as a natural and a cultural resource. But, in the base of those landscapes we can meet social practices, an intangible heritage that give cohesion to the natural and cultural aspects. Our scope it's to debate ideas comparing examples. Between the well preserved Chinese rice heritage landscapes, supported by millenary social and farming practices, and the abandoned European ter...
Ups-and-downs of Mediterranean terraced landscapes: comparative study of four c...
Barata, Filipe Themudo; Capelo, Sofia; de Mascarenhas, José ManuelBeyond politic decisions, landscape changes mostly result from the economic perception that each community has of its own territory and from the social practices related with agriculture and technical knowledge. Among the cultural landscapes with heritage value, the terraced ones are common in Mediterranean area. Terraces are used by people, or not, in reply to challenges arisen from economic, social and politi...
Is it possible to keep heritage landscapes original functions? Remarks on land ...
Capelo, Sofia; Barata, F. T.; de Mascarenhas, J.M.The most important value contained in the territory is the cultural landscape in which heritage appears as the structuring value in its invention. In fact, the authors have been studying problems concerning the valorisation and sustainable development of heritage landscapes, through cultural parks and related monitoring indicators, and often facing problems how to deal with land degrading problems. Those are c...
Linear sweep voltammetry: a cheap and powerful technique for the identification...
Capelo, Sofia; Menino Homem, P.; Cavalheiro, J.; Fonseca, I.T. E.The potentialities of linear sweep voltammetry (LSV) for the characterization of the tarnish layer formed on pure and sterling silver samples exposed in the chapel and in the museum, at the Cathedral of Porto, in Portugal, are well demonstrated in this study. The technique allows the identification of the constituents of the thin tarnishing layers and also its relative abundance. A much more complex composition...
Controlling pollution effects on metallic cultural heritage using linear sweep ...
Capelo, Sofia; Menino Homem, P.; Cavalheiro, J.; Fonseca, I. T. E.This work demonstrates the potentialities of the linear sweep voltammetry (LSV) for monitoring the composition of the tarnishing layers formed on silver and on the silver-copper alloys exposed to atmospheres contaminated with pollutants, such as H2S and chloride ions, among others. A collection of silver and sterling silver coupons exposed during periods of 1 and 12 months, at the Holy Altar of the Chapel and a...
Monitoring Corrosion Products on Metal Artefacts by Linear Sweep Voltammetry (LSV)
Capelo, Sofia; Homem, P.; Cavalheiro, J.; Fonseca, I.T.E.Metallic surfaces are highly sensitive to their surroundings, and prone to react with airborne pollutants to form complex layers. Electrochemical techniques have the possibility of simultaneously identifying different electroactive compounds [1]. The high sensitivity of Linear Sweep Voltammetry (LSV) allows the detection of extremely thin surface films before they became visible. LSV leads to reduction peaks, w...
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