Browsing by Issue Date, starting with "2023-05"
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- Irradiation damage on CrNbTaVWx high entropy alloysPublication . Martins, Ricardo; Correia, J.B.; Czarkowski, P.; Miklaszewski, R.; Malaquias, A.; Mateus, R.ABSTRACT: CrNbTaVWx high-entropy alloys have been developed for plasma facing components to be applied in nuclear fusion reactors. The CrNbTaVWx (x = 1 and 1.7) compositions were prepared by ball milling and consolidated at 1600 degrees C under 90 MPa. To study the irradiation resistance of these materials, deuterium plasmas were used to irradiate the samples in the PF-1000U facility with 1 and 3 discharges. Structural changes before and after irradiation were analyzed by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy. Nuclear reaction analysis was carried out with 1000 and 2300 keV 3He+ ion beams to evaluate the profile and amount of retained deuterium on the irradiated samples. After irradiation, the sample with higher W content revealed swelling and melting for all discharges, while in the case of CrNbTaVW only blisters were observed. The deuterium retention was higher for CrNbTaVW1.7 when compared with CrNbTaVW for 3 discharges applied.
- The paleoenvironmental and thermal histories of the Permian Irati formation shale in the paraná basin, Brazil: An integrated approach based on mineralogical and organic imprintsPublication . Rocha, Rocha, H.V.; Sant'Anna, L.G.; Rodrigues, Cristina F.A.; Mendes, Márcia; Pereira, Zélia; Lopes, Gilda; Fernandes, Paulo; Pereira, Egberto; Tassinari, Colombo C. G.; Sousa, M.J. Lemos deABSTRACT: Mineralogical assemblages and organofacies are important sources of information to recover the paleoenvironmental and thermal histories of shale deposits. In this study, a detailed qualitative and quantitative characterization of the Permian Irati Formation (Assistência Member) shale is based on mineralogical (XRD and SEM-EDS) and organic components (TOC, Rock-Eval pyrolysis, organofacies, TAI, fluorescence and vitrinite reflectance measurements) and provides integrated data about sediment provenance, depositional environment, diagenesis, and thermal history, while supporting interpretations on the Paraná Basin (PB), Brazil, paleogeography and its correlation to the southwest Gondwana. The results revealed a prevailing type I/II kerogen, with type III kerogen being also present but mainly confined along the paleoshoreline of the PB. The dominance of fluorescent amorphous organic matter (AOM) combined with framboidal pyrite suggests microbial activity in an anoxic-dysoxic neritic-marine paleoenvironment. Additionally, common to abundant well-preserved phytoclasts, as well as the occurrence of Botryococcus braunii, indicates freshwater influx in a brackish marine depositional setting. Immature to early-oil window thermal maturities prevail across the PB, according to the organic maturation indicators. The combined analysis between the organic matter evolution with clay mineralogy, such as the occurrence of interstratified clays (e.g., I/S) and its positive correlation with depth suggest that burial diagenesis reached the transition to early catagenesis on the north, southeast, and south of the basin, attributing a shale oil potential for the Irati Formation on a regional scale. Local scale imprints of the Early Cretaceous Paraná-Etendeka Large Igneous Province (LIP), and its thermal effect in the Irati Formation shale components, are recorded as clay authigenesis (e.g., smectite webby texture and clay coating development), crystallization of minerals by low to high-grade of thermal alteration (e.g., corrensite, talc, lizardite and diopside), and by local scale gas-window maturities. Such thermal alteration, identified in the proximity to intruded sills and dykes, led to a heterogeneous organic maturation pattern with implications on shale gas and shale oil potential of the Irati Formation shale, demonstrating that these subjects in the Paraná Basin should be assessed locally.
- Portuguese Fossil Database: first phase reportPublication . Fialho, Pedro; Da Silva, Roberto; Patrocínio, Sofia; Costa, Bruno; Burigo, AndréABSTRACT: Knowing what has been previously done before starting a new study is of primary importance when conducting novel scientific research. Portugal has more than two centuries of research in Paleontology; however, this information is currently scattered. The present project aims to compile all fossil occurrences reported in the country by creating an occurrence-based paleobiodiversity database. We collected and compiled three primary data types through an exhaustive bibliographic search and analysis process: (i) references to scientific publications; (ii) listed taxa; (iii) occurrences per taxon. Some of our medium/long-term goals are: (i) the analysis of the taxonomic distribution of Portuguese fossil taxa; (ii) estimation of yearly scientific production indexes; (iii) identification of areas with significant paleontological potential. Presently, we have completed the analysis of 330 scientific publications and recorded a total of 11,011 fossil occurrences. We were able to identify over 380 Portuguese outcrops, with 58,246 fossils attributed to 2,890 taxa.
- From piggery wastewater to wheat using microalgae towards zero wastePublication . Ferreira, Alice; Figueiredo, Daniel; Ferreira, Francisca; Marujo, Ana; Bastos, Carolina R. V.; Martin-Atanes, Guillermo; Ribeiro, Belina; Štěrbová, Karolína; Santos, Cláudia Marques dos; Acién, F. Gabriel; Gouveia, LuisaABSTRACT: Microalgae production is still expensive, driving the need to lower costs while strengthening the industry's environmental sustainability. Microalgae are recognized tools for efficient wastewater treatment, offering the recycling of nutrients and water for agriculture, and producing biomass rich in growth-promoting compounds to improve plant productivity and resistance to adverse conditions. The use of wastewater can reduce cultivation costs as it is a source of nutrients and water. Alternative low-cost methods can significantly decrease harvesting costs, which represents one of the most expensive steps of the whole process.The goal of this work was to evaluate the potential of wastewater-grown microalga biomass for agriculture purposes. To reduce production costs, the microalga Tetradesmus obliquus was produced in pre-treated photo-Fenton (PF) piggery wastewater in combination with the use of different harvesting techniques - electro-coagulation, flocculation, and centrifugation, and different combinations. From the wastewater treatment pro-cess, two fractions (biomass and supernatant) were evaluated for germination and growth of wheat (Triticum aestivum L.) plants and compared to non-harvested microalga culture (MC), distilled water, and Hoagland (synthetic) solution. The concentrated resulting from PF was also tested as a biofertilizer.The results confirm that both biomass and supernatants are useful for agricultural applications. The obtained biomass elicited a 20-105 % increase in germination index compared to the control, while supernatants were inhibiting. The opposite trend was observed at later stages of wheat growth, where the nutrient-enriched su-pernatants and the PF concentrate (PF-CC) increased the number of tillers (3-5) and leaves (30-42) after 83 days. Wheat plants treated with MC and PF-CC produced similar number of ears (3.4 & PLUSMN; 0.5 and 6.0 & PLUSMN; 4.1 ears per plant, respectively) than the synthetic control (5.7 & PLUSMN; 1.4) after 182 days. All fractions obtained from the process can be used in a zero-waste process.
- Transformative business models for decarbonization: The case of Web Summit award-winning start-upsPublication . Costa, Evaldo; Bento, Nuno; Fontes, MargaridaABSTRACT: The social demand for decarbonization has placed increasing pressure on businesses to contribute actively to mitigate the risks of a climate disruption resulting from carbon emissions. The development of new business models capable of transforming conventional systems of production and consumption and replacing them with more sustainable alternatives is one critical step towards this goal. This study combines several streams of literature including sustainability transitions and business model theories to investigate the key elements of the business models that have the potential to transform the provision of goods and services in a way that enables the transition to a low carbon society. We investigate the start-ups and relate to the extent to which they avoid, shift or improve the production or consumption of goods and services in a way that significantly reduces carbon emissions. For that, we analyze the start-ups that received innovation awards on the Web of Summit between 2014-2020.
- Opportunities and challenges for companies diversifying into the value chain: The case study of marine renewable energy technologiesPublication . Conceição, Oscarina; Sousa, Cristina; Fontes, MargaridaABSTRACT: Marine renewable energy technologies (MRET) have the potential to become an important source of clean energy and, simultaneously, contribute to the revitalisation of other sectors (Fontes et al, 2021). The realization of such potential requires the construction of a new industrial value chain that combines the competences associated with the new technologies with complementary resources and competences present in the existing industry (Makitie et al, 2018).
- LUÍS REBÊLO : missão e dedicação ao litoral e aos sistemas dunaresPublication . Nave, Silvia; Monteiro, José HipólitoRESUMO: Luís Rebêlo foi o principal impulsionador, nas últimas duas décadas, da área de geologia costeira da Instituição onde trabalhou durante 33 anos nos Serviços Geológicos Portugueses. O seu abrupto falecimento veio provocar uma enorme perda e um dano de difícil reparação, dada a falta que faz um especialista consagrado em geologia costeira à Unidade de Geologia, Hidrogeologia e Geologia Costeira. Licenciou-se em Geologia pela Faculdade de Ciências da Universidade Clássica de Lisboa. O início da sua carreira profissional deu-se como Hidrogeólogo da PGIRH/T – Projecto Tejo, num breve período entre 1988 e 1989, data em que ingressou, como geólogo, e sob orientação de Hipólito Monteiro, no Departamento de Geologia Aplicada dos Serviços Geológicos de Portugal (SGP), da então Direcção-Geral de Minas e Serviços Geológicos. Em 1993, com a criação do novo Departamento de Geologia Marinha, transitou para esta unidade onde iniciou o seu percurso de investigação no domínio da Geologia Costeira.
- The Role of Mild Alkaline Pretreatment in the Biorefinery Upgrade of Spent Coffee GroundsPublication . Ribeiro, Gabriel Mota; Martins, Pedro L.; Oliveira, Ana Cristina; Carvalheiro, Florbela; Fragoso, Rita; Duarte, Luís C.ABSTRACT: This work proposes a valorization route for spent coffee grounds (SCG), a widespread lignocellulosic residue, encompassing the production of: biomethane, lignin, and oligosaccharides as value-added products obtained simultaneously during a mild alkaline (NaOH) pretreatment. The studied operational variables were the reaction time (60-240 min), temperature (25-75 degrees C), and the NaOH concentration (0-2.5 M). The severity factor suitably describes the global process kinetics, with higher severities (log Mo = 5.5) yielding high product yields, 18.02% and 13.25% (on dry SCG basis) for lignin and oligosaccharides (XGMOS), respectively. Solid yield is negatively impacted by all studied variables (at the 95% confidence level). Conversely, XGMOS yield is positively influenced both by time and catalyst concentration, whereas lignin yield is only (positively) influenced by catalyst concentration. Optimal balance between product formation and potential operational costs is putatively achieved when using 0.625 M NaOH, at 50 degrees C for 60 min. The mild alkaline pretreated biomass (MAP-SCG) was compared to untreated SCG for biomethane production by anaerobic co-digestion with pig slurry (PS), using a ratio of biomass/PS = 1/3 (volatile solids (VS) basis). The proposed valorization route enabled the sequential production of 6.25 kg lignin, 6.36 kg oligosaccharides, and 138.05 kg biomethane per 100 kg of non-extracted SCG (and 287.60 kg pig slurry), in an integrated process that is technically feasible and promotes the circular bioeconomy.
- Synthesis, photophysical and electrochemical properties of π-conjugated pyrene based down-shifting molecules with fluorinated aryl groupsPublication . Barros, Helio; Esteves, M. Alexandra; Brites, Maria JoãoABSTRACT: Pyrene molecule, with excellent photophysical properties (strong absorption cross section, excellent emission properties and a long-excited state lifetime), excellent thermal and photochemical stability, has been widely used as a building block for the synthesis of pyrene-based fluorophores for optoelectronic applications. In this work, we report the synthesis of two series of pyrene-pi-A compounds, series I (3-6) and II (10-13), in which nitro, cyano, cyanoacrylonitrile and cyanoacrylic acid as electron acceptor groups are connected to the pyrene core via aryl or fluoroaryl pi-conjugating bridges. The incorporation of fluorine atom on the pi-extension bridge cause a slightly red-shift at emission wavelength (lambda em) in solution and polymethylmethacrylate (PMMA) films and in-crease the Stokes shift due to greater stabilization of molecular orbitals in the excited state, especially for series I. Solvatochromic measurements and theoretical computational studies suggest a higher intramolecular charge transfer in the excited state for series II when compared to series I due to their stronger electron acceptor moieties. All pyrene derivatives are stable and exhibited initial mass loss at temperature above 200 degrees C. The good photophysical and thermal properties of the synthesized pyrene derivatives, associated with high molar ab-sorption coefficients in the UV spectrum and good fluorescence emission in the range of 430-480 nm (series I) and 505-567 nm (series II) in PMMA films, make them possible candidates for organic light-emitting diode (OLED) and luminescent down-shifting (LDS) layers for stable perovskite solar cells, respectively.
- Climate Policies in Decarbonization Strategies: A computational approachPublication . Fontes, Margarida; Alves, Tiago; Bento, NunoABSTRACT: The transition to a low-carbon society should accelerate to avoid an increase in the temperatures above 1.5º to 2ºC, and this is unlikely to occur without policy intervention (IPCC, 2022). Given the complexity of the problem to be addressed, recent debates have increasingly pointed to the need of adopting a broader view on policy intervention (Weber and Rohracher, 2012; Hekkert et al., 2020). This entails a move beyond a single focus on economic competitiveness and growth, towards a focus on societal problems or “grand challenges”, leading to the emergence of the concept of transformative innovation policy (Schot and Steinmueller 2018; Dierks et al, 2019). This new rationale implies the consideration of a much broader range of policy objectives, targets and instruments, as well as the notion that a mix of policies needs to be deployed to achieve the desired goals (Rogge and Reichardt 2016). While this policy rationale has started to enter innovation policy agendas, it remains to be seen to what extent it is reflected in the actual policies being implemented (Casula, 2022; Peñasco et al., 2021). On the other hand, it is also unclear whether the directions set by those policies align with the visions and strategies for decarbonization and whether there are still uncovered areas.