Browsing by Author "Rodrigues, B."
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- Caracterização Geoquímica da Formação da Brejeira, Grupo do Flysch do Baixo Alentejo : resultados preliminaresPublication . Fernandes, Paulo; Jorge, Raul CG Santos; Rodrigues, B.; Pereira, Zélia; Oliveira, José Tomás
- Carbon isotope record of the Middle to Late Jurassic, Callovian-Oxfordian, from the Algarve Basin, PortugalPublication . Borges, Marisa; Fernandes, Paulo; Rodrigues, B.; Googhue, R.
- Degradation of a Lithium Iron Phosphate based Cathode in Lithium-ion Batteries after 2000 cyclesPublication . Plancha, Maria João; Rangel, C. M.; Rodrigues, B.; Azevedo, F.
- Degradation of lithium Iron phosphate-based cathode in lithium-ion batteries: a post-mortem analysisPublication . Plancha, Maria João; Rangel, C. M.; Rodrigues, B.; Azevedo, F.; Silva, A. A.Commercial Li-ion batteries were studied in view to investigate the degradation of the positive electrode in an end-of-life battery condition. Post-mortem analyses were performed by using SEM and DRX techniques; structural and morphological changes after prolonged cycling were evaluated comparatively to a fresh cathode sample. The cycling procedure based on a constant current (CC)/constant voltage (CV) charge and CC discharge was executed, being the condition of end-of-life battery achieved after submitting the Li-ion battery to nearly 2000 charge/discharge cycles. EDS analysis revealed zirconium element as the dopant of a LiFePO4-based cathode of the battery under study. According to X-ray diffraction results for the fresh (charged condition) cathode, the positive electrode includes in its constitution a mixture of crystalline compounds, LiFePO4 and FePO4. SEM images displayed and DRX patterns obtained for the cycled cathode showed modifications compared to the fresh cathode results, evidencing the degradation of the battery at the end-of-life: decrease in the density of microparticles associated to areas where the insertion/de-insertion occurs; decrease of the LiFePO4/FePO4 ratio; both results pointed out to the occurrence of battery loss capacity with the imposed charge/discharge cycles.
- Detrital zircon geochronology of the Carboniferous Baixo Alentejo Flysch Group (South Portugal); constraints on the provenance and geodynamic evolution of the South Portuguese ZonePublication . Rodrigues, B.; Chew, David; Jorge, Raul CG Santos; Fernandes, Paulo; Pires, Cristina Veiga; Oliveira, José TomásU–Pb detrital zircon data from the Baixo Alentejo Flysch Group in the South Portuguese Zone show significant age differences between formations. The Visean Mértola Formation and Serpukhovian to early Bashkirian Mira Formation are dominated by zircons in the 316–388?Ma age range, whereas the late Bashkirian to late Moscovian Brejeira Formation is dominated by zircons with an age range of 498–687?Ma. Detrital zircons spanning an age range of 0.9–1.1?Ga are present in the Brejeira Formation but are absent in the Mértola and Mira formations. Detrital zircon ages of the Mértola and Mira formations indicate provenance from an extra-basinal source (Ossa–Morena Zone) with a minor intra-basinal contribution (South Portuguese Zone). The abundant presence of detrital zircon with age ranges of 500–750 and 0.9–1.1?Ga in the Brejeira Formation suggests a sediment source from the Avalon–Meguma terranes with limited recycling from the SW Portugal Domain. The different inferred source areas for the Baixo Alentejo Flysch Group formations are attributed to the presence of a forebulge that was formed in Mid-Visean times during the foreland phase of the South Portuguese Zone. The forebulge acted as a physical barrier separating sub-basins that accumulated the Mértola–Mira and Brejeira sediments respectively.
- Maturação orgânica da Bacia Algarvia: resultados preliminares e implicações para a prospecção de hidrocarbonetosPublication . Fernandes, Paulo; Rodrigues, B.; Borges, Marisa; Matos, V.A Bacia Algarvia constitui um importante depocentro localizado no sul de Portugal, cuja sucessão estratigráfica do Mesozóico se distribui entre o Triásico Sup. e o Cretácico Inf. Com a fnalidade de se conhecer o grau de maturação da Bacia Algarvia foram medidos os poderes reflectores da vitrinite (%Rm) de 53 amostras da sua sucessão estratigráfica. Os valores encontrados estão entre os 0,82 e os 1,34%Rm, indicando que a sucessão estratigráfica está dentro da "janela do petróleo". Os resultados são pertinentes na análise da Bacia Algarvia e em futuros trabalhos de prospecção de hidrocarbonetos.
- Maturação orgânica e palinoestratigrafia da Sondagem RUIVO-1, região imersa da Bacia Algarvia: contribuições para a prospecção de hidrocarbonetosPublication . Borges, Marisa; Fernandes, Paulo; Rodrigues, B.; Matos, V.A sondagem RUIVO-1, localizada na região imersa da Bacia Algarvia, foi estudada com a finalidade de se caracterizar o grau de maturação e conhecer as idades das unidades litológicas com base na bioestratigrafia dos dinoflagelados. O estudo do poder reflector da vitrinite indica que a sucessão do Mesozóico está matura em relação à "janela do petróleo". Os dinoflagelados evidenciaram a presença de uma espessa sucessão do caloviano, discordante sobre os depósitos evaporíticos do ?Triásico-Hetangiano.
- A re-assessment of the organic maturation and palynostratigraphy of the wells Ruivo-1 and Corvina, offshore Algarve Basin PortugalPublication . Fernandes, Paulo; Borges, Marisa; Rodrigues, B.; Matos, V.The Algarve Basin is the southernmost geological province of portugal. The nowledge of its offshore geology is limited to a few hydrocarbon exploration wells and seismic profiles. Two of these wells, Ruivo-1 and Corvina, were studied in order to assess its organic maturation levels and age using the biostratigraphy of dinoflagellate cysts. The well Ruivo-1 intercepted a thick Callovian succession whereas the well Corvina intercepted a thick Oxfordian succession. Both Jurassic successions are within the oil-window.