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http://hdl.handle.net/10174/50
2024-03-29T08:16:38ZChemical stability of new nafion membranes doped with bisphosphonic acids under Fenton oxidative conditions
http://hdl.handle.net/10174/36202
Title: Chemical stability of new nafion membranes doped with bisphosphonic acids under Fenton oxidative conditions
Authors: Teixeira, António P. S.; Teixeira, Fátima C.; Rangel, C. M.
Abstract: The development of new proton exchange membranes for PEM technology in fuel cells and electrolysers with increased durability is paramount to system's lifetime and scalability. In this work, new modified Nafion membranes doped with bisphosphonic acids are proposed with increased resilience to chemical degradation by H2O2/Fe2+, mimicking ex-situ radical attack to membrane structure. Relevant properties were evaluated throughout Fenton's test using fluoride ion release and gravimetry determinations, and by ATR-FTIR spectros-copy and SEM before and after the chemical degradation. The new membranes showed a very good chemical stability after oxidative degradation under Fenton's test conditions at 80 degrees C, with more durability than Nafion 115 commercial membrane. After chemical degradation, the proton conduction of the membranes was assessed through EIS which reveals a decrease in the proton conductivity of all membranes, with the new modified membranes showing a smaller decrease of their proton conduction properties than Nafion 115 membrane. Fluoride ion release, weight loss measurements and ATR-FTIR spectros-copy data analysis suggest degradation of the side chain of the ionomer.2023-07-31T23:00:00ZNew proton conductive membranes of indazole- and condensed pyrazolebisphosphonic acid-Nafion membranes for PEMFC
http://hdl.handle.net/10174/33455
Title: New proton conductive membranes of indazole- and condensed pyrazolebisphosphonic acid-Nafion membranes for PEMFC
Authors: Teixeira, António P. S.; Teixeira, Fátima C.; Rangel, C. M.
Abstract: In this work, new doped Nafion membranes for PEMFC are prepared by casting with 1 wt% loading of the prepared indazole- and condensed pyrazolebisphosphonic acids (AzBPs). The new membranes were analysed by ATR-FTIR spectroscopy and their morphology was examined by SEM. Membranes were evaluated for water uptake and ion exchange capacity (IEC), and their hydration number was estimated. The proton conduction properties of the modified membranes were evaluated by electrochemical impedance spectroscopy (EIS), at different temperatures (30, 40, 50 and 60 ºC) and relative humidity (RH) (40, 60 and 80%). The proton conductivities of all membranes increase with increasing temperature and RH. Also, all new membranes doped with AzBPs exhibited higher proton conductivities than Nafion N-115, used as a reference and tested at the same experimental conditions, with values up to 1.5-fold. Results show that the incorporation of AzBPs dopants on Nafion membranes enhances the proton conduction throughout the modified membranes. The best proton conductivity was observed for membranes with AzBP1 as dopant, with a value of 94 mS cm-1. These results indicate that the Nafion membranes doped with indazole- and condensed pyrazolebisphosphonic acids are a promising approach for new membranes for PEMFC with improved proton conductivity.2022-06-30T23:00:00ZEffective Communication in Transition Care During Shift Change
http://hdl.handle.net/10174/32709
Title: Effective Communication in Transition Care During Shift Change
Authors: Fernandes, Filipe; Dias, Almeida; Araújo, Isabel; Marreiros, Goreti; Machado, Joana; Dawa, Hossam; Vicente, Henrique; Neves, José
Abstract: The aim of this study is to examine the effective communication pro cess during shift changes in a transitional care unit; communication should be clear, concise and relevant. The caregivers should be able to understand their mates needs and wants, and they should understand what is happening. Indeed, it will be study if there is inconsistency in the communication process during shift change, since there are some factors that could be affecting the consistency, such as inadequate time for communication, lack of awareness about the needs of other team members and unclear expectations from managers, a process carried out by interviewing employees who have experience in transitional care. The intervie wees are asked about their past experiences and what they think are the most important points for effective communication. No doubt this article will discuss the communication challenges and opportunities that arise when a caregiver trans fers care from one shift to the next, with effective communication being the key. On the other hand, in this work is also set a Logic Programming based framework
that nurses may use to optimize their insight into how caregivers may make their communication more effective by understanding the needs of both parties involved in the shift change process.2022-01-01T00:00:00ZStorage time evaluation of a residue from wine industry as a microencapsulated corrosion inhibitor for 1 M HCl
http://hdl.handle.net/10174/31305
Title: Storage time evaluation of a residue from wine industry as a microencapsulated corrosion inhibitor for 1 M HCl
Authors: Furtado, Luana; Rocha, Janaina; Ponciano, Jose; Nascimento, Rafaela; Seidl, Peter; Guimaraes, Maria Jose; Tonon, Renata; Cabral, Lourdes Maria; Mattos, Gabriela
Editors: Chan, Sammy; Duh, Jenq-Gong
Abstract: The effect of a residue from wine industry was investigated as a corrosion inhibitor for API P110 steel in hydrochloric acid. The extract was characterized using Fourier-transform infrared spectroscopy (FTIR), hydrogen nuclear magnetic resonance (1H NMR) and chromatography. The influence of temperature (303–333 K) and grape peel extract concentration were studied using gravimetric and electrochemical experiments. The coupon surfaces were evaluated using microscopy techniques, FTIR-ATR and the contact angle. The by-product exhibited high weight loss efficiencies at 303 K with 4.0 g/L of the extract (83.81%) even after storage. The inhibition increased with the addition of an inorganic enhancer, indicating a synergistic effect between the active compounds and maximum efficiency of 94.48%. Polarization tests indicated that the inhibitor adsorbs on anodic and cathodic regions. The surface characterization techniques confirmed the formation of an organic film and a less attacked surface was observed for the inhibited system.2020-01-01T00:00:00Z