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  1. 1

    Assessment of geomorphological diversity indices of Portugal mainland

    Publicação
    por Lopes, Catarina
    Outros Autores: Pereira, Paulo; Pereira, Diamantino; Gonçalves Teixeira, Zara Fani
    ABSTRACT: The results from the assessment of diversity, evenness, and richness indices of geomorphology of mainland Portugal are presented, based on four hierarchical levels of geomorphological units. These indices were calculated on a hexagonal analytical grid, testing eight cell dimensions (1 km, 2 km, 5 km, 10 km, 15 km, 20 km, 25 km and 30 km). The 10 km dimension provided a clearer definition of regional geomorphological specificities, which correspond to areas of higher diversity and richness. The results related to evenness did not allow for establishing such clear relationships with geomorphological units. However, the diversity and evenness indices, along with richness, provide a more comprehensive assessment of spatial diversity. These results are part of the assessment of Portugal’s geodiversity and are essential for comparative analyses between various elements of geodiversity and with other natural and cultural elements.
    2025 artigo Portugal acesso aberto
  2. 2

    A importância da Formação de Coimbra no contexto dos sistemas petrolíferos da Bacia Lusitânica

    Publicação
    por Sousa, João
    Outros Autores: Duarte, Luis; Sêco, Sérgio
    RESUMO: Baseado na Resumo: Baseado na análise de 19 sondagens onshore e offshore na margem ocidental da Bacia Lusitânica (Portugal), é apresentada a caracterização do potencial petrolífero da Formação (Fm) de Coimbra, uma unidade carbonatada de idade sinemuriana (Jurássico Inferior). O bom reconhecimento estratigráfico, sedimentológico e geoquímico, em conjunto com a análise de logs de gamma ray permite evidenciar a variabilidade vertical e lateral dos principais intervalos ricos em matéria orgânica desta unidade, com a Fm de Coimbra a assumir se como uma das unidades geradoras da Bacia Lusitânica. A ocorrência de óleo e gás na Fm de Coimbra, registada em 10 entre 19 sondagens analisadas, demostram a existência de vários sistemas petrolíferos associados a esta unidade.
    2025 artigo Portugal acesso aberto
  3. 3

    Enhancing Proton Conductivity of SPEEK Based Membranes by Incorporation Graphene Oxide / Bisphosphonic acid dopant [Resumo]

    Publicação
    por Teixeira, Fatima
    Outros Autores: Teixeira, António Paulo Silva; Rangel, Carmen M.
    ABSTRACT: The most commercially successful membrane for applications in fuel cell and electrolyzers, perfluorinated sulfonic NafionR, exhibits relevant performance limitations due to its dependence on water content with consequent proton mobility restrictions, environmental concerns and very high cost. Poly(etheretherketone) (SPEEK) polymer appears as a versatile non-fluorinated alternative for a low-cost and a more environmentally friendly membrane. Our previous studies showed that the incorporation of biphosphonic acid dopants (BPs) into the mentioned polymeric matrices, improves membrane proton conduction and durability1-5. In this work, we prepared and evaluated new doped SPEEK membranes using graphene oxide (GO) with bisphosphonic acid functionalities as dopant (GOBP), anticipating superior membranes properties, including proton conductivity.
    2025 documento de conferência Portugal acesso aberto
  4. 4

    Investigating ocean acidification off the Iberian Margin: Oceanographic results from the CARBO-ACID cruise

    Publicação
    por Salgueiro, Emilia
    Outros Autores: da Silva Magalhães, Vitor Hugo; Matos, Lelia; Rebotim, Andreia; Sousa, Fátima; Schweizer, Magali et al.
    ABSTRACT: The EUROFLEETS+ CARBO-ACID cruise was carried out to investigate the ocean acidification effects on the carbonate organisms (coccolithophores, pteropods, foraminifera, and corals) along the W Iberian Margin. Samples of the water column, plankton, corals and sediments were collected to investigate the acidification effects since the pre-industrial Era until the present. These samples will allow not only to reconstruct the pH variability under different environmental conditions, but also to estimate the biogeochemical changes along the oceanic coastal waters as the anthropogenic influence increases. The obtained results will contribute to better understand and model the biological response to the expected ocean temperature and pH changes in the future. This work aims to document the type of samples collected, the planned analyses strategy and to show the first oceanographic obtained results in the study area.
    2025 artigo Portugal acesso aberto
  5. 5

    Heterogeneity of the mixed siliciclastic-carbonate deposits of the upper Cabo Carvoeiro formation (Lower-Middle Jurassic), Lusitanian Basin, Portugal

    Publicação
    por Barata, Joao
    Outros Autores: Duarte, Luis; Azerêdo, Ana Cristina; Gomes, J.
    ABSTRACT: The upper CC5 member of the Cabo Carvoeiro Formation (Toarcian-Aalenian(?)) of the Lusitanian Basin is characterized by grainstone facies with quartz grains, ooids and intraclasts. These facies are observed exclusively at Peniche, contrasting with the hemipelagic marly sediments of coeval outcrop sections in the basin. A detailed facies scheme reveals the relative local heterogeneity of the succession on outcrops, while the analysed subsurface data helps to better understand its regional heterogeneity. Lateral facies variability on outcrop is observed to occur through gradation, interfingering or pinching-out geometries. Coeval sections in the analysed offshore wells are generally characterized by micritic mudstone facies, which might transition laterally into the Peniche grainstones through similar geometric relationships based on the existing conceptual model. The relative heterogeneity of this sedimentary system is defined in this study by integrating outcrop and subsurface data, allowing for its perception at different observation scales.
    2025 artigo Portugal acesso aberto
  6. 6

    Influence of Inhibitors Generated in Lignocellulosic Hydrolysates from Group of Acids on the Growth of Strains TG1 and Tuner of Escherichia coli

    Publicação
    por Gaspar, Suelen S.
    Outros Autores: Alves Ferreira Caturra, Júnia Aparecida; Moniz, Patricia; Silva-Fernandes, Talita; Silvestre, Adriana I. R; Torrado, Ivone et al.
    ABSTRACT: Concerns over fossil fuels are of increasing interest in biorefineries that utilize lignocellulosic residues. Besides sugars, inhibitors are formed during biomass pretreatment, including acetic acid (AI) and formic acid (FI), which can hinder microbial fermentation. The TG1 and Tuner strains of Escherichia coli were subjected to various acid concentrations. Samples were taken during fermentation to monitor growth, sugar consumption, biomass yield, and product yield. With increasing AI, the TG1 strain maintained stable growth (0.102 1/h), while xylose consumption decreased, and product formation improved, making it better suited for high-acetic-acid industrial applications. In contrast, the Tuner strain performed better under low-inhibitor conditions but suffered metabolic inhibition at high AI levels, compensating by increasing lactic acid production-an adaptation absent in TG1. However, Tuner showed greater resistance to formic acid stress, sustaining higher growth and ethanol production, whereas TG1 experienced a greater metabolic decline but maintained stable acetic acid output. Both strains experienced inhibition in formic acid metabolism, but TG1 had a higher yield despite its lower overall robustness in formic acid conditions. The use of TG1 for value-added compounds such as ethanol or formic acid may help to avoid the use of chemicals that eliminate acetic acid. Tuner could be used for lactic acid production, especially in hydrolysates with under moderate concentration.
    2025 artigo Portugal acesso aberto
  7. 7

    Green Catalytic Transformation of CO₂ to Syngas Using Aerogels [Resumo]

    Publicação
    por Paninho, A. B.
    Outros Autores: Messias, Sofia; Fernandes, I.; Rangel, Carmen M.; Nunes, A. V. M.; Branco, Luis et al.
    2025 documento de conferência Portugal acesso aberto
  8. 8

    The materials of historical monuments: characterisation of the mortars of the Roman aqueduct of Zaghouan-Carthage

    Publicação
    por Carvalho, Fernanda
    Outros Autores: Lima, Maria Margarida Rolim Augusto; Silva, Teresa; Veiga, João Pedro
    ABSTRACT: The Zaghouan-Carthage Roman aqueduct was the largest built by the Roman Empire at the time, and its archaeological remains bear witness to the excellence of Roman construction. Its importance over the centuries makes it a unique case study for characterising the different types of mortar used. This work aims to study these materials, considering their functions, especially as structural elements or as render, to relate the chemical and mineralogical characteristics observed to both the function and historical context of the monument. Using a multi-analytical approach, the preservation of samples was prioritised whenever possible. The results indicate that mortars with a structural function have higher silicon contents than those used as render. In the case of water conduit coatings, the mortars were formulated with ground ceramics to develop hydraulic properties and ensure the waterproofing material. However, it was not possible to identify a characteristic pattern related to the historical construction periods.
    2025 artigo Portugal acesso aberto
  9. 9

    Enhanced borohydride oxidation kinetics with Au@MOF-808 nanocomposite electrocatalysts with ultra-low Au loading

    Publicação
    por Belhaj, Ines
    Outros Autores: Becker, J. Alexander; Viana, Alexandre M.; Gusmão, Filipe M. B.; Chaves, Miguel; Pereira, Eulália et al.
    ABSTRACT: The highly stable metal-organic framework (MOF) composed of[Zr6O4(mu 3-OH)4(OH)6(H2O)6(BTC)2]& sdot;nH2O units (MOF-808) was modified by incorporating gold (Au) nanoparticles and functional groups to enhance electrocatalytic activity for the borohydride oxidation reaction (BOR). Three composite materials (Au@MOF-808, Au@MOF-808-NH2, and Au@MOF-808-SH) were prepared by the incorporation of Au in structurally related MOFs, MOF-808, MOF-808-NH2, and MOF-808-SH, respectively. These composite materials were evaluated as anodic electrocatalysts for BOR in alkaline media using cyclic voltammetry and chronoamperometry. Among the prepared materials, Au@MOF-808-NH2 exhibited the highest BOR activity, with an apparent activation energy of 15.3 kJ mol-1, a reaction order of 0.6, an anodic charge transfer coefficient of 0.63, and a number of exchanged electrons of 4.4. The latter was significantly below the theoretical eight-electron value, indicating the presence of alternative reaction pathways. Notably, this material achieved a high mass-specific BOR peak current of 4.23 A mu gAu-1, demonstrating outstanding electrocatalytic efficiency despite the ultralow noble metal loading. These results underscore the potential of Au@MOF-808-NH2 as a cost-effective and scalable anodic electrocatalyst for high-performance direct borohydride fuel cells.
    2026 artigo original Portugal acesso aberto
  10. 10

    Nanobubble-enhanced oxygen transfer in bacterial nanocellulose production: Comparative evaluation with static and airlift systems

    Publicação
    por Rodrigues, Ana Cristina
    Outros Autores: Martins, Daniela; Carvalho, Ricardo; Marques, Susana; Belo, Isabel; Espina, Begona et al.
    ABSTRACT: Despite the unique properties of bacterial nanocellulose (BNC), oxygen limitation during large-scale production impairs microbial metabolism and cellulose synthesis, leading to high production costs and limited commercial success. Static fermentation can achieve high titers, but industrially it is operationally challenging. Agitated systems like airlift (AL) bioreactors, allow faster production but typically yield lower titers. This study pioneered the use of an agitated bioreactor equipped with a nanobubble (NB) generator, and its performance was compared with that of static and AL systems, employing a newly isolated Komagataeibacter sp. strain from kombucha cultivated in Eucalyptus bark hydrolysate and corn steep liquor. Key monitored parameters included dissolved oxygen, cell density, pH, sugar and lactic acid contents, and BNC production. The obtained BNC was characterized for its crystallinity, thermal stability, degree of polymerization, morphology and fiber size. The AL-and NB-derived BNC exhibited a denser network structure, lower crystallinity index, and lower polymerization degrees than that from static culture. NB technology generated stable nanobubbles (size: 95.8 f 12.9 nm; zeta potential:-14.2 f 8.6 mV). At 1 L. min-1 airflow, compared to AL, the NB bioreactor achieved a 6-fold higher volumetric mass transfer coefficient (kLa 35.9 f 1.2 h-1) and oxygen transfer rate (OTR: 309.7 f 10.2 mg.L-1.h-1). It supported greater cell density but maintained a similar BNC volumetric productivity to that of the AL (0.023 g.L-1.h-1), and moderately higher (near 280%) than that of static culture (0.0082 g.L-1.h-1). Thus, the improved oxygen levels provided by the NB system favored biomass growth rather than BNC production, suggesting that further optimization is needed to redirect carbon flux toward BNC production.
    2026 artigo Portugal acesso aberto