DSpace Collection:http://hdl.handle.net/10174/11202024-03-29T13:54:30Z2024-03-29T13:54:30ZNovas Membranas Condutoras de Protões para Células de CombustívelTeixeira, António P.S.Teixeira, Fátima C.Rangel, C. M.http://hdl.handle.net/10174/289112021-01-27T11:42:24Z2020-11-01T00:00:00ZTitle: Novas Membranas Condutoras de Protões para Células de Combustível
Authors: Teixeira, António P.S.; Teixeira, Fátima C.; Rangel, C. M.
Editors: Gonçalves, H.; Romero, M.
Abstract: As membranas de permuta protónica continuam a ser um material fundamental e um desafio chave no desenvolvimento das células de combustível. Neste trabalho foram preparadas, usando um método de casting, novas membranas de Nafion dopadas com 1 wt% de diferentes ácidos bisfosfónicos (BPs). As novas membranas foram avaliadas relativamente à sua capacidade de absorção de água (water uptake), por gravimetria, à sua capacidade de troca iónica (IEC), através da determinação da presença de grupos ionizáveis na membrana utilizando titulação potenciométrica ácido-base, e ao grau de hidratação. As novas membranas apresentaram valores superiores aos da membrana de Nafion utilizada como referência. A condutividade protónica das novas membranas foi avaliada por Espectroscopia de Impedância Eletroquímica (EIS), em diferentes condições de humidade relativa e de temperatura, tendo apresentado valores de condutividade protónica superiores às da membrana comercial de Nafion em todas as temperaturas e humidades relativas testadas.2020-11-01T00:00:00ZFully Informed Vulnerable Road Users - Simpler, Maybe BetterFernandes, BrunoVicente, HenriqueRibeiro, JorgeCapita, AntónioAnalide, CésarNeves, Joséhttp://hdl.handle.net/10174/276762020-03-03T13:53:44Z2019-01-01T00:00:00ZTitle: Fully Informed Vulnerable Road Users - Simpler, Maybe Better
Authors: Fernandes, Bruno; Vicente, Henrique; Ribeiro, Jorge; Capita, António; Analide, César; Neves, José
Editors: Indrawan-Santiago, Maria; Pardede, Eric; Salvadori, Ivan; Steinbauer, Matthias; Khalil, Ismail; Anderst-Kotsis, Gabriele
Abstract: Vulnerable Road Users (VRUs) are all those with an increased vulnerability on the road, in particular non-motorised ones. Until now, the emphasis has been in politics more focused on drivers, vehicles and infrastructures. However, recent developments show a shift in other directions, with researchers now devoting efforts to improve VRUs' safety. Hence, this work focuses on pedestrian walking and crossing behaviour, attitudes, motivations and habits, being grounded on an approach to Knowledge Representation and Reasoning centred on logic programming, which establishes a formal logical inference engine that is complemented with an Artificial Neural Network line to computation.2019-01-01T00:00:00ZFull Informed Road Networks Evaluation: Simpler, Maybe BetterRibeiro, JorgeFernandes, BrunoAnalide, CésarVicente, HenriqueNeves, Joséhttp://hdl.handle.net/10174/263412020-01-09T11:58:15Z2019-01-01T00:00:00ZTitle: Full Informed Road Networks Evaluation: Simpler, Maybe Better
Authors: Ribeiro, Jorge; Fernandes, Bruno; Analide, César; Vicente, Henrique; Neves, José
Abstract: The aim of this work is to categorize the current state of a road network, to determine quality of service and to assess the need to establish a program for maintenance or investment with respect to an evaluation of the user’s network satisfaction. It was designed to obtain information on the level of service provided and road network conditions, using a series of hypothetical questions. The instruments (logical functions or predicates) used considered only two or three attributes, so that respondents are able to easily comprehend and evaluate the scenarios presented to them. On the other hand, the hypothetical scenarios within each instrument were generated by varying the levels of the attributes entropy in a way that is specific to each of them, i.e., this study investigates the measurement of road network structure according to this assumption. Existing measures of heterogeneity, connectivity, accessibility, and interconnectivity are reviewed and supplemental measures are proposed, including measures of entropy, connection patterns, and continuity.2019-01-01T00:00:00ZSBA-15 with sulfonic acid groups as acid solid catalyst for glycerol conversion into biofuel additivesHenriques, PCastanheiro, Jhttp://hdl.handle.net/10174/248902019-02-26T11:33:02Z2018-09-30T23:00:00ZTitle: SBA-15 with sulfonic acid groups as acid solid catalyst for glycerol conversion into biofuel additives
Authors: Henriques, P; Castanheiro, J
Editors: Castro, E
Abstract: Acetalization of glycerol with pentanal was carried out in the presence of SBA-15 with sulfonic acid groups. Materials with different amounts of sulfonic acid groups were prepared. It was observed that the catalytic activity increases with the amount of sulfonic acid groups on SBA-15 until a maximum. With high amount of sulfonic groups, a decrease of activity is observed.
All catalysts show high selectivity to (2-butyl-1,3-dioxolan-4-yl) methanol.
The catalyst [SO3H]3-SBA-15 showed a good stabilized.2018-09-30T23:00:00Z