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An Impedance Study on the sPEEK/ZrO2 Membranes for Direct Methanol Fuel Cell Ap...

V. B. Silva; V. S. Silva; L. M. Madeira; S. P. Nunes; A. Mendes

Electrochemical impedance experiments were carried out in order to study the influence of the ZrO2 inorganic incorporation on the proton conductivity of sulfonated poly(ether ether ketone) (sPEEK) membranes. The impedance data was fitted to an extension of Randles' circuit, within the inorganic content and temperature ranges considered. The model fits quite well for ZrO2 loads up to 10 wt.%. Such a model allows...


Non-Fluorinated Membranes Thickness Effect on the DMFC Performance

Vasco Freitas Silva; Valter B. Silva; R. Reissner; S. Vetter; A. Mendes; L. M. Madeira; S. P. Nunes

In order to study the influence of the proton exchange membrane thickness on the direct methanol fuel cell (DMFC) performance, sulfortated poly (ether ether ketone) (sPEEK) membranes with a sulfonation degree (SD) of 42% and thicknesses of 25, 40, and 55 pm were prepared, characterized, and tested in a DMFC. These polymeric membranes were tested in a DMFC at several temperatures by evaluating the current-voltag...


The diseases we cause: Iatrogenic illness in a department of internal medicine

Madeira, S; Melo, M; Porto, J; Monteiro, S; Pereira de Moura, JM; Alexandrino, MB; Moura, JJ

BACKGROUND: The aim of this study was to estimate the incidence, main causes, and risk factors of iatrogenic disease occurring in a department of internal medicine. METHODS: Over a 1-year period, physicians systematically filled out a 2-page questionnaire for all patients admitted to the ward. A database was created and the data were statistically analyzed. Patients undergoing immunosuppressive, chemo-, or rad...


Estupor recurrente idiopático. ¿Un caso de estupor por endocepinas?

Melo, M; Madeira, S; Gaspar, E; Pereira de Moura, JM; Freire-Gonçalves, A; Alexandrino, MB; Moura, JA


Zirconium Oxide Modified Sulfonated Poly(ether ether ketone) Membranes for Dire...

V. Silva; B. Ruffmann; H. Silva; A. Mendes; M. Madeira; S. Nunes


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Fundação para a Ciência e a Tecnologia Universidade do Minho   Governo Português Ministério da Educação e Ciência Programa Operacional da Sociedade do Conhecimento União Europeia