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Radioatividade natural de solos na envolvente da antiga central termoelétrica de Sines: impactes da combustão de carvão
No full textABSTRACT: For 36 years, the coal combustion in Sines thermal power plant generated a complex mixture of gases and particles that were partially emitted into the atmosphere and the environment. The determination of radiological parameters in soils surrounding the power plant reveals that soils in the southern area have higher activity concentration of natural radionuclides (40K, 232Th, and 238U), as well as higher exhalation rates and emanation coefficients of 222Rn and 220Rn than those located at north. The higher values of radiological parameters in the southern area are explained by dispersion of gases and particles driven by the preferential direction of winds and the proximity to storage facilitates of coal and products derived from combustion. The higher exhalation rates and low emanation coefficients of thoron indicates that K and Th may be accumulated and encapsulated in the mineral fraction of ash particles while U, preferentially bounded to organic matter, was mobilized during coal combustion. The results do not indicate a significant radiological risk, although it is higher in the southern area.RESUMO: Durante 36 anos, a combustão do carvão na central termoelétrica de Sines gerou uma mistura complexa de gases e partículas que foram parcialmente emitidas para a atmosfera e para o ambiente. A determinação de parâmetros radiológicos nos solos no entorno da central termoelétrica revela que os solos da área sul apresentam maior concentração de atividade de radionuclídeos naturais (40K, 232Th e 238U), assim como maiores taxas de exalação e coeficientes de emanação de 222Rn e 220Rn do que os localizados a norte. Os valores mais elevados dos parâmetros radiológicos na zona sul são explicados pela dispersão de gases e particular conduidas pela direção preferencial dos ventos e pela proximidade das instalações de armazenamento de carvão e produtos derivados da combustão. As maiores taxas de exalação e os baixos coeficientes de emanação do torão indicam que K e Th podem ser acumulados e encapsulados na fração mineral das cinzas enquanto o U, preferencialmente ligado à matéria orgânica, foi mobilizado durante a combustão do carvão. Os resultados não indicam um risco radiológicosignificativo, embora este seja maior na zona sul
A Machine Learning Model for Procurement of Secondary Reserve Capacity in Power Systems with Significant vRES Penetrations
No full textABSTRACT: The growing investment in variable renewable energy sources is changing how electricity markets operate. In Europe, players rely on forecasts to participate in day-ahead markets closing between 12 and 37 h ahead of real-time operation. Usually, transmission system operators use a symmetrical procurement of up and down secondary power reserves based on the expected demand. This work uses machine learning techniques that dynamically compute it using the day-ahead programmed and expected dispatches of variable renewable energy sources, demand, and other technologies. Specifically, the methodology incorporates neural networks, such as Long Short-Term Memory (LSTM) or Convolutional neural network (CNN) models, to improve forecasting accuracy by capturing temporal dependencies and nonlinear patterns in the data. This study uses operational open data from the Spanish operator from 2014 to 2023 for training. Benchmark and test data are from the year 2024. Different machine learning architectures have been tested, but a Fully Connected Neural Network (FCNN) has the best results. The proposed methodology improves the usage of the up and down secondary reserved power by almost 22% and 11%, respectively
Stratigraphic re-evaluation of Coimbra Formation (Sinemurian) through gamma-ray in wells
No full textRESUMO: Os dados litostratigráficos de subsuperfície da Bacia Lusitânica apresentam uma grosseira resolução e interpretação, sendo a conceptualização da evolução da bacia substanciada principalmente por afloramento. A espectrometria de radiação gama tem demonstrado ser uma grande utilidade na correlação entre unidades geológicas em afloramento e subsuperfície,
reconhecimento de fácies margosas ricas em matéria orgânica, e análise sequencial. Nesta investigação, este método é aplicado à Formação de Coimbra registada em 19 sondagens onshore e offshore da bacia sendo feita uma reinterpretação litostratigráfica e uma análise da evolução sequencial desta unidade.ABSTRACT: Subsurface stratigraphic data on the Lusitanian Basin present a coarse interpretation and resolution, and the conceptualization of its evolution is mostly constrained to outcrop studies. Gamma-ray spectrometry has shown promise in the subsurface of organic marly successions by correlating geological units, identifying marly and organic-rich intervals, and providing sequence analysis. In this investigation, this method is applied to the Coimbra Formation, wich is recorded in 19 onshore and offshore wells, providing new insights into this unit’s stratigraphy and its sequential evolution
Evolution and trends of the kaolin market in Portugal
No full textRESUMO: A evolução do mercado português de caulino revela uma tendência crescente de produção com flutuações, geralmente mais sensível às crises económicas nacionais porque o consumo é maioritariamente doméstico. As importações, que eram muito baixas até à década de 1980, aumentaram até ao final da década seguinte, mas posteriormente tenderam a diminuir gradualmente. As exportações apresentam crescimento desde o início do século até uma relativa estabilização com flutuações. A relação entre produção e consumo aparente, a partir de 2010 mostra um excedente de produção, sugerindo que parte do caulino explorado não está sendo comercializado. O problema não se deve a uma sobre-exploração dos recursos, mas provavelmente à necessidade de uma exploração mais seletiva com impacto na qualidade do caulino e na utilização integral das matérias-primas exploradas. Dada a atual situação geopolítica, espera-se um aumento das exportações nacionais de caulino.ABSTRACT: The evolution of the Portuguese kaolin market shows a production growing trend with peaks and troughs, generally more sensitive to national economic crises because consumption is mainly domestic. Imports, which were very low until the 1980s, increased until the end of the following decade, but subsequently tended to gradually decline. Exports show growth from the beginning of the century with subsequent relative stabilization with peaks and troughs. The relationship between production and apparent consumption from 2010 onwards shows a surplus production of kaolin, suggesting that part of the exploited kaolin is not being sold. The problem is not due to an over-exploitation of resources, but probably to the need for more selective exploitation with an impact on the quality of the kaolin and the full use of the exploited raw materials. Given the current geopolitical situation, an increase in national exports of kaolin is expected
Contribution to the improvement of the Buçaco Carboniferous Basin geological mapping
No full textRESUMO: A revisão da cartografia geológica da área onde se situa a Bacia Carbonífera do Buçaco (BCB) mostrou que os seus limites se encontram ou fortemente tectonizados ou em discordância angular sobre litologias neoproterozóicas e paleozóicas. Os sedimentos mesocenozóicos cartografados também estabelecem limites com as unidades da BCB. No limite oriental da bacia foi identificada uma falha normal gerada em regime distensivo, ativa durante a deposição das unidades litoestratigráficas datadas do Gzheliano, enquanto no limite ocidental foi identificada uma tectónica compressiva tangencial (direção ENE-WSW), com transporte de material para ENE, posterior ao evento extensional. Os episódios tectónicos descritos estão associados às fases finais da Orogenia Varisca.ABSTRACT: The geological cartography review of the area where the Bussaco Carboniferous Basin (BCB) is located showed that its limits are either strongly tectonized or in angular discordance over Neoproterozoic and Paleozoic lithology’s. Mapped mesocenozoic sediments also settle limits with the BCB units. At the eastern limit of the basin, a normal fault generated in an extensional regime was identified, active during the deposition of lithostratigraphic units dated from the Gzhelian, while on the western boundary, a tangential compressive tectonic was identified (ENE-WSW direction), with material transport to ENE, posterior to the extensional tectonic event. The described tectonic episodes are associated with the final stages of the Variscan Orogeny
EGU Geosciences Education Field Officers: an international programme to promote geosciences teaching
No full textRESUMO: O programa Geosciences Education Field Officers (GEFO), criado e apoiado pelo Comité de Educação da European Geosciences Union, teve início em 2019 em seis países (Espanha, França, Índia, Itália, Marrocos e Portugal) e foi expandido em 2022 estando, atualmente, em desenvolvimento em 19 países europeus e não europeus. Está a ser preparada uma nova expansão do programa, prevista para 2025. O principal objetivo desta iniciativa é promover o desenvolvimento do ensino das geociências, através da organização e realização de oficinas interativas para professores, no ativo e em formação, dos ensinos básico e secundário. Esta iniciativa pretende fomentar o ensino das geociências, particularmente a componente prática, e contribuir para a concretização Pacto Ecológico Europeu e dos Objetivos de Desenvolvimento Sustentável das Nações Unidas.ABSTRACT: The Geosciences Education Field Officers (GEFO) programme, launched and supported by the Education Committee (EC) of the European Geosciences Union (EGU), began in 2019 in six countries (France, India, Italy, Morocco, Portugal, and Spain), was expanded in 2022, and now is under developing in 19 European and non-European countries. The latter was supported by the Commission on Geoscience Education of the International Union of Geological Sciences. For 2025 is being prepared a new expansion of the programme. The main goal of this initiative is to promote the development of geoscience teaching, by organizing and running interactive workshops to primary and secondary school teachers. The GEFO are geoscience teachers, in service or retired, and/or researchers, and besides performing workshops for teachers in their countries, they attend teacher´s conferences/webinars promoting EGU GEFO programme and produce publications regarding their activity. Between April 2019 and December 2023, more than 160 workshops were held, in which participated approximately 3000 teachers, eight articles, 18 abstracts and a chapter of a book were published; twelve talks and 11 webinars were presented at scientific meetings. Furthermore, EGU GEFO are working with national and international educational institutions as teacher’s associations and geosciences scientific structures. An important partnership that allowed writing the Barcelona Manifest (Manifesto for the teaching of Geoscience), a collaboration between EC and institutions from 10 different countries and, so far more than 30 associations
and institutions already signed and are promoting the document. GEFO programme is an initiative that aims to encourage the teaching of geosciences, particularly its practical component, and intend to contribute to the achievement of the European Green Deal and the United Nations Sustainable Development Goals
Consortium of microalgae/nitrogen-fixing bacteria as a next-generation biofertilizer, biostimulant and biopesticide
No full textABSTRACT: This study aims to provide insights into a new consortium of a microalga, twelve nitrogen-fixing (N-fixing) bacteria and a cyanobacterium. The microalga Tetradesmus obliquus (T), in conjunction with various N-fixing bacteria and the cyanobacterium Synechocystis sp. PCC 6803 (S), the N-fixing bacterium Sphingobacterium sp. L13G8 (5), cultivated in complete Bristol medium and in Bristol-NaNO3 free conditions, were examined. The study encompassed the analysis of their consortia, including evaluation of their growth, and potential as a biostimulant, biofertilizer and biopesticide, and assessed for sedimentation performance for targeted applications. The T and N-fixing bacteria consortia had higher growth in Bristol NaNO3-free media. The triple culture TS5 had the highest growth parameter (2.4 OD540) in the same medium, followed by T5. The consortia were employed to ascertain the efficacy of their biostimulants and biofertilizers on watercress (Lepidium sativum) and to determine the potency of their biopesticides against the fungal pathogens Fusarium oxysporum and Rhizoctonia solani (in certain consortia). Consortium T5 demonstrated the most significant impact on the seeds germination index (212.7%) and root length (6.0 cm) of L. sativum. The same consortium had a significant impact on the shoot length (4.4 cm) of L. sativum. Among all consortia that were examined, T5 exhibited significant inhibitory effects on the growth of F. oxysporum (60.6%) and R. solani (69.2%). In the same consortium, the rate of microalgal biomass sedimentation was enhanced by the N-fixing bacterium (0.4 cm h-1). Consortium T5 was the most effective in relation to growth and biomass sedimentation efficiency, in addition to its use as a biostimulant, biofertilizer and biopesticide. The created combination of microalga and N-fixing bacterium represents significant progress in the field of microalga cultivation, with notable benefits including improved biomass sedimentation and enhanced agricultural practices, as well as environmental friendliness and safety
Contributions of the Correspondence Analysis as a methodology for the selection of case studies in the evaluation of the environmental degradation of abandoned mining areas
No full textRESUMO: A negligência para com as áreas mineiras abandonadas no último século tem vindo a preocupar a comunidade científica por poderem representar problemas ambientais, o que tornou necessária a implementação de metodologias capazes de identificar e selecionar casos representativos de áreas alvo para estudo. A aplicação da análise fatorial das correspondências binárias permitiu verificar as semelhanças entre as áreas em estudo e, desta forma, a seleção representativa dos diferentes casos de estudo. Para este trabalho, com a aplicação desta metodologia, foi possível selecionar seis casos de estudo, que são representativos, segundo os critérios adotados, dos principais grupos referentes à degradação ambiental de áreas mineiras abandonadas em Portugal, inseridas na Província Portuguesa Metalogenética Estano-Tungstífera: mina da Cerdeirinha, mina do Pintor, mina do Ramalhoso, mina de Regoufe, mina de Vale das Gatas e mina da Bejanca.ABSTRACT: The neglect of abandoned mining areas in the last century has been worrying the scientific community due to their possible representation of environmental problems, which has made it necessary to implement methodologies capable of identifying and selecting representative cases of target areas for study. The application of factor analysis of binary correspondences made it possible to verify the similarities between the areas under study and, in this way, the representative selection of the different case studies. For this work, with the application of this methodology, it was possible to select six study cases, which are representative, according to the adopted criteria, of the main groups referring to the environmental degradation of abandoned mining areas in Portugal, inserted in the Portuguese
Metallogenetic Province Tin-Tungsten: Cerdeirinha mine, Pintor mine, Ramalhoso mine, Regoufe mine, Vale das Gatas mine and Bejanca mine
Pre-Solve Methodologies for Short-Run Identification of Critical Sectors in the ACSR Overhead Lines While Using Dynamic Line Rating Models for Resource Sustainability
No full textABSTRACT: Most transmission system operators (TSOs) use seasonally static models considering extreme weather conditions, serving as a reference for computing the transmission capacity of power lines. The use of dynamic line rating (DLR) models can avoid the construction of new lines, market splitting, false congestions and the degradation of lines in a cost-effective way. The operation of power systems is planned based on market results, which consider transactions hours ahead of real-time operation using forecasts with errors. The same is true for the DLR. So, during real-time operation TSOs should rapidly compute the DLR of overhead lines to avoid considering an ampacity above their lines' design, reflecting the real-time weather conditions. Considering that the DLR of the lines can affect the power flow of an entire region, the use of the complete indirect DLR methodology has a high computation burden for all sectors and lines in a region. So, this article presents and tests three pre-solve methodologies able to rapidly identify the critical sector of each line. These methodologies solve the problem of the high computation burden of the CIGR & Eacute; thermodynamic model of overhead lines. They have been tested by using real data of the transmission grid and the weather conditions for two different regions in Portugal, leading to errors in the computation of the DLR lower than 1% in relation to the complete CIGR & Eacute; model, identifying the critical sector in significantly less time
Extraction and assessment of the colouring capacity of Arthrospira platensis-derived pigments
No full textABSTRACT: This study presents a zero-waste biorefinery approach for the sequential extraction of phycocyanin and chlorophyll from Arthrospira platensis, followed by the valorisation of the remaining biomass as a plant biostimulant. Natural deep eutectic solvents were screened for phycocyanin recovery, with the mixture proline:glycerol:sorbitol:water (1:1:1:13 molar ratio) showing the highest potential (1.15 g⋅100 g-1; p < 0.05). An initial ultrasound-assisted cell wall disruption step significantly enhanced phycocyanin yield by 400–450 % relative to the untreated control (p < 0.05). A response surface methodology optimised extraction achieved a recovery yield of 8.26 g⋅100 g-1 at 39.7 °C and 127.9 min. The phycocyanin-rich extract was used to mimic the blue colour of commercial blue gin, with a minimal colour difference (ΔE) of 4.53. Subsequent chlorophyll extraction from the phycocyanin leftovers yielded an extract that successfully coloured a commercial green alcohol-free apple liquor (ΔE = 3.93) and green gin (ΔE = 1.65). Finally, the residual biomass demonstrated a significant biostimulant capacity, increasing the germination index of various seeds by 80–150 % compared to water (p < 0.05). This work highlights the potential of A. platensis as a sustainable source for natural colourants and agricultural inputs