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Structure, fabric and paragenesis of the Ruivos tungsten-gold-bearing spot : inner-granite shear zone network of Ponte da Barca, Northern Portugal
No full textRESUMO: Na região de Ponte da Barca, os cruzamentos de zonas de cisalhamento multifásicas, N0°-7°E / N70°E, são o foco principal, de mineralização intra-granítica e hidrotermal de W e Au + As, especialmente quando um terceiro conjunto de rupturas (~N30°E), reticula o volume de maciço adjacente àquelas intersecções. O estudo detalhado da junção de cisalhamentos em Boivão – Ruivos mostrou que quanto mais variados são os azimutes e inclinações das rupturas que afetam um compartimento granítico, maior é a diversidade de mineralizações, que podem incluir, scheelites precoces, associadas a microclina, albite e ouro ± prata ± bismuto, teluretos e selenietos, por sua vez, associados a adulária. A análise do petrofabric
permitiu determinar estágios sucessivos de libertação / fixação de ouro a partir de arsenopirite relacionados com a deformação progressiva.ABSTRACT: In Ponte da Barca region, the intersections of multistage shear zones, N0°-7°E and N70°E, are the main focus, of inner-granite, hydrothermal W and Au + As mineralization, especially when a third set of ruptures (~N30°E), reticulates the adjacent volume of massif. The detailed study of the Boivão – Ruivos shear junction showed that the more varied are
the strikes and deeps of the ruptures that affect a granite compartment, the greater is the diversity of mineralizations, which may include, early scheelite associated with microcline and albite and later gold ± silver ± bismuth, tellurides and selenides, associated with adularia. The petrofabric analysis allowed to determine successive stages of gold liberation out from arsenopyrite, related to progressive deformation
Oligo-Holocene morpho-sedimentary evolution of the lower course of the Piranhas-Açu river, Rio Grande do Norte (Brazil)
No full textRESUMO: É objetivo deste trabalho identificar, cartografar e interpretar as principais unidades morfo-sedimentares datáveis do Oligocénico à atualidade, no baixo curso do rio Piranhas-Açu. Durante o Oligocénico e Miocénico ocorreram pulsos vulcânicos na Bacia Potiguar, gerando basaltos. Durante o provável Pliocénico a Gelasiano, houve o preenchimento sedimentar culminante (Formação Barreiras). No Plistocénico, a etapa de incisão fluvial na Formação Barreiras e unidades anteriores, gerou vales com escadarias de terraços. No Holocénico, o dominante controlo eustático gerou várias unidades costeiras que representam sucessivos sistemas de ilhas barreiras-laguna. Caracterizou-se a evolução do canal Piranhas-Açu. A representação das unidades morfo-sedimentares em um mapa com escala 1:100.000 permite a observação dos dados espacializados e suporta as interpretações e discussões de dados.ABSTRACT: This work aims to identify, characterize and map the main sedimentary lithostratigraphic units ascribed to date between the Oligocene and Present, in the lower Piranhas-Açu River. During the Oligocene and Miocene, volcanic pulses in the Potiguar Basin generate the basalts of the Tibau Formation. During the Pliocene, a culminating sedimentary filling (Barreiras Formation) covered the study area. In the Pleistocene, paleovalley incision in the Barreiras Formation and older units was made, but the evolution also included the genesis of alluvial terraces. Holocene eustatic
control on coastal sedimentation in the study area is interpreted as the dominant, recorded by several units of sandy barrier-lagoon systems. The geological evolution of the Piranhas-Açu channel was characterized. The cartography of the morpho-sedimentary units on a 1:100.000 scale map, allows the observation of spatialized data in the area and supports the interpretation and discussion of data
Production of sustainable aviation fuel precursors using the oleaginous yeast Rhodotorula toruloides PYCC 5615 cultivated on eucalyptus bark hydrolysate
No full textABSTRACT: Sustainable aviation fuels (SAF) obtained from renewable sources of carbon can reduce carbon dioxide emissions and contribute for mitigating climate changes. In the present study, the yeast Rhodotorula toruloides PYCC 5615 was found to be highly promising for the bioconversion of eucalyptus bark hydrolysate and the accumulation of intracellular lipids which were further thermochemically processed to bioenergy intermediaries for SAF production. Two growth medium formulations were tested. Eucalyptus bark hydrolysate, obtained by steam explosion followed by enzymatic hydrolysis, was supplemented with yeast nitrogen base medium or with corn steep liquor and mineral medium. The latter produced the highest fatty acid content and productivity (30 % w/w and 0.11 g/ (L.h) respectively). Thereafter, the whole yeast biomass (WB) and the de-oiled biomass (DOB), obtained after lipid extraction, were processed into Bio-crude using a hydrothermal liquefaction (HTL) reactor, with a yield of approximate to 40 % (w/w). The two obtained Bio-crude fractions and the yeast lipids fraction (YL) were further upgraded by hydrodeoxygenation (HDO), to remove oxygen atoms and increase the hydrocarbon content, resulting in a Bio-crude composed of linear long-chain fatty acids suitable for processing to SAF. The best Bio-crude characteristics was observed for WB and YL fractions, with 34.8 % and 40.7 % of hydrocarbons, respectively. Both WB and YL hydrocarbons were composed of C15-C17 compounds. These results demonstrate the potential of an integrated process based on microbial oils from R. toruloides PYCC 5615 to produce SAF precursors from Eucalyptus bark residues, contributing for the sustainable jetfuel bioproduction process
Eventos meteorológicos extremos de tipo ciclone tropical e seus grandes impactos em Moçambique, no período de 1926 a 2021
No full textABSTRACT: The monitoring and prediction of tropical cyclones in Mozambique rely on short databases that sometimes lead to inadequate interpretations due to the lack of precision in equipment and limited human resources. Misinterpretations are also related to the notoriously unstable climatic conditions in the oceanic domain, especially in the Mozambique Channel
region, particularly in recent years. It is essential to have a better understanding of the history of these events, as Mozambique has been frequently devastated by tropical cyclones. In this paper, we present our contribution to reconstructing the historical record of these events, their human and material impacts on Mozambican territory from 1926 to 2021. In this interval, 33 tropical cyclones were highly destructive, causing severe human, material and environmental impacts. The research has shown that extreme meteorological events of the tropical cyclone type cause greater human,
material and infrastructure damage, mainly because of their duration after landfall and because they are associated with heavy rainfall after energy dissipation.RESUMO: A monitorização e previsão dos ciclones tropicais em Moçambique baseiam-se em bases de dados curtas que, por vezes, conduzem a interpretações deficientes devido à falta de precisão dos equipamentos e de recursos humanos. As interpretações erróneas estão também relacionadas com as condições climáticas reconhecidamente instáveis no domínio oceânico e principalmente na região do canal de Moçambique, sobretudo nos últimos anos. É necessário conhecer melhor a história destes eventos, uma vez que Moçambique tem sido frequentemente devastado por ciclones tropicais. Neste trabalho procurou-se construir o histórico destas ocorrências, os seus impactos humanos e materiais no território moçambicano, no período de 1926 a 2021. Neste intervalo, 33 ciclones tropicais foram bastante
devastadores e tiveram graves impactos humanos, materiais e ambientais. A pesquisa mostrou que os inventos extremos meteorológicos de tipo ciclone tropical causam maior danos humanos, materiais e nas infraestruturas,
principalmente pela sua duração no contente depois do landfall e por estarem associados a grandes precipitações de chuvas depois da dissipação energética
Evaluation of the level of contamination in sediments from watercourses of the Caveira Mining System (Grândola)
No full textRESUMO: O presente trabalho, inserido no Projeto GeoMatRe, visa o levantamento das condições mais atualizadas no que toca aos parâmetros físico-químicos numa mina de drenagem ácida. Uma situação crítica que ocorre na área mineira de Caveira, em Grândola, Portugal, abandonada desde a década de 60 do século passado. O objetivo passa por analisar as condições de contaminação de Elementos Potencialmente Tóxicos (EPT) nos sedimentos que ocorrem quer em fases móveis e dissolvidas na água intersticial dos sedimentos, quer em fases mais imóveis. Neste trabalho é realizada uma caracterização geral da área do sistema mineiro, verificando-se um nível de contaminação da área, através da análise do Índice de Geoacumulação (IGEO) e do Fator de Enriquecimento (FE), onde os elementos Cu, Pb, Zn, As e Hg demonstram ser os principais EPT’s na região, apresentando valores, em alguns dos casos, milhares de vezes acima dos estipulados pelas normas nacionais.ABSTRACT: The following work is inserted in the GeoMatRe Project, in which the conditions of the most updated physical and chemical parameters of an Acid Mine Drainage are analysed. This study shows that the mining area of Caveira, in Grândola, Portugal, which was abandoned since the 60’s, presents a critical situation of contamination, with high levels of Potentially Toxic Elements (PTE) present in the whole mining area and its surroundings. It is intended,
within the scope of the project, and through geochemical analysis, to observe the conditions of contamination by PTE in native sediments from the mine tailing, which occur either in mobile phases, dissolved in the interstitial water of the sediments, or in more immobile phases. With that in mind, preparation of methodologies for geochemical studies were carried out, namely Fusion for further analysis of the element’s total forms, and Partial Digestion with Aqua Regia, for quantification of the most easily extractable forms, which represent the most contaminating fraction. Ultimately, Inductively Coupled Plasma Optical mission Spectrometer (ICP-OES) was used to analyse and quantify the previously prepared samples. It is herein presented a general characterization of the mining system, through analysis and understanding of the Geo-accumulation Index (IGEO) and the Enrichment Factor (EF), tools that improve the visualization of the previously obtained data on the ICP-OES, demonstrating the content and chemical nature of the contaminating elements (As, Cu, Zn, Pb and Hg) as main PTE’s in the region, presenting values, in some cases, thousands of times higher than those stipulated by Nacional standards
Building materials produced and used in Portugal that may raise concern from the radiological protection point of view
No full textRESUMO: Na construção civil, é comum a utilização de materiais geológicos, seja diretamente ou incorporados nos materiais de construção. A presença de radionuclídeos naturais nesses materiais pode resultar em exposição à radiação ionizante, seja por meio da exposição externa à radiação gama ou pela inalação do gás radão. A Agência Portuguesa do Ambiente estabelece medidas adequadas para controlar os materiais de construção, visando proteger a população contra radiações ionizantes no interior dos edifícios. Um estudo foi conduzido com o objetivo de identificar os materiais de construção
produzidos e utilizados em Portugal que possam gerar preocupações radiológicas, com especial ênfase na radiação gama. Neste trabalho, apresentam-se os resultados relativos ao índice de concentração de atividade (I), relacionado com a dose de radiação gama proveniente dos materiais de construção, permitindo rastrear os materiais que podem fazer com que o nível de referência de dose seja excedido. O estudo destaca maior preocupação radiológica em relação aos granitos e pozolana natural, bem como alguns subprodutos e produtos industriais, como cinzas volantes, argila expandida, betão com agregado granítico e determinados pavimentos e revestimentos cerâmicos.ABSTRACT: Geological materials are commonly used in construction, either directly or incorporated into building materials. The presence of natural radionuclides in these materials can lead to exposure to ionizing radiation, either
through external exposure to gamma radiation or by inhalation of radon gas. The Portuguese Environment Agency establishes appropriate measures to control building materials, aiming protect the population from ionizing radiation inside buildings. A study was conducted to identify building materials produced and used in Portugal that may raise radiological concerns, with a particular focus on gamma radiation. In this work, the results related to the activity concentration index (I), linked to the dose of gamma radiation from building materials, are presented, allowing the screening of materials that may cause the dose reference level to be exceeded. The study highlights greater radiological concern regarding granites and natural pozzolan, as well as some by-products and industrial products, such as fly ash, expanded clay, concrete with granite aggregate, and specific ceramic floor and coatings
Biopolymers Derived from Forest Biomass for the Sustainable Textile Industry
No full textABSTRACT: In line with environmental awareness movements and social concerns, the textile industry is prioritizing sustainability in its strategic planning, product decisions, and brand initiatives. The use of non-biodegradable materials, obtained from non-renewable sources, contributes heavily to environmental pollution throughout the textile production chain. As sustainable alternatives, considerable efforts are being made to incorporate biodegradable biopolymers derived from residual biomass, with reasonable production costs, to replace or reduce the use of synthetic petrochemical-based polymers. However, the commercial deployment of these biopolymers is dependent on high biomass availability and a cost-effective supply. Residual forest biomass, with lignocellulosic composition and seasonably available at low cost, constitutes an attractive renewable resource that might be used as raw material. Thus, this review aims at carrying out a comprehensive analysis of the existing literature on the use of residual forest biomass as a source of new biomaterials for the textile industry, identifying current gaps or problems. Three specific biopolymers are considered: lignin that is recovered from forest biomass, and the bacterial biopolymers poly(hydroxyalkanoates) (PHAs) and bacterial cellulose (BC), which can be produced from sugar-rich hydrolysates derived from the polysaccharide fractions of forest biomass. Lignin, PHA, and BC can find use in textile applications, for example, to develop fibers or technical textiles, thus replacing the currently used synthetic materials. This approach will considerably contribute to improving the sustainability of the textile industry by reducing the amount of non-biodegradable materials upon disposal of textiles, reducing their environmental impact. Moreover, the integration of residual forest biomass as renewable raw material to produce advanced biomaterials for the textile industry is consistent with the principles of the circular economy and the bioeconomy and offers potential for the development of innovative materials for this industry
Instrumental recording of the physical effects of the Tunguska Event at the Geophysical and Astronomical Observatory of the University of Coimbra
No full textRESUMO: A explosão de Tunguska ocorreu na Sibéria Central na manhã de 30 de junho de 1908 (cerca de 0h13, hora GMT), devastando uma vasta área de floresta e desencadeando grandes perturbações geofísicas, meteorológicas e biológicas. Abalos sísmicos, flutuações na pressão atmosférica e anomalias no campo magnético terrestre foram registados em diversas regiões da Eurásia setentrional e central. Nessa época, já se faziam observações magnéticas, meteorológicas e sísmicas no Observatório Meteorológico e Magnético da Universidade de Coimbra (OMMUC). Neste trabalho procedeu-se à análise dos registos sísmicos e magnéticos do património documental do antigo OMMUC, de modo a identificar qualquer perturbação que pudesse ser atribuída ao Evento de Tunguska. Foi possível concluir que, enquanto a vibração sísmica causada pela explosão de Tunguska foi registada, o mesmo não aconteceu com a perturbação magnética.ABSTRACT: The Tunguska explosion occurred in Central Siberia on the morning of June 30, 1908 (around 0 h 13 min, GMT), devastated a large area of forest and triggered major geophysical, meteorological and biological disturbances. Seismic shocks, fluctuations in atmospheric pressure and anomalies in the geomagnetic field have been recorded in several places in northern and central Eurasia. At that time, magnetic, meteorological and seismic observations were made at the Meteorological and Magnetic Observatory of the University of Coimbra (Observatório Meteorológico e Magnético da Universidade de Coimbra; OMMUC). In this work, we proceeded to the analysis of the seismic and magnetic records belonging to the documental heritage of the old OMMUC, in order to identify any disturbance that could be attributed to the Tunguska Event. It was possible to conclude that, while the seismic vibration caused by the Tunguska explosion was registered, the same did not happen with the
geomagnetic disturbance.Observatório Geofísico e Astronómico da Universidade de Coimbr
Assessment of piggery wastewater treatment in vertical flow constructed wetlands: role of plants and aeration
No full textABSTRACT: Piggery wastewater (PWW), rich in pollutants, poses significant environmental risks if not properly treated. Natural treatment processes, such as constructed wetlands (combined action of plants, substrates, and microbes) and microalgae cultivation, offer sustainable and low-cost alternatives for managing these effluents while enabling resource recovery. This study represents an initial step toward optimizing key operational conditions, such as aeration (passive and active), vegetation presence, and the use of single or sequential Vertical Flow Constructed Wetlands (VFCWs), for the treatment of piggery wastewater, using different experimental setups, at a laboratory scale. Indoor experiments were conducted over an 8-week period to optimize operational conditions for the treatment of PWW. The VFCWs, arranged in two stages and operated in series through gravity flow, were fed daily and monitored weekly. The best removal rates of total Kjeldahl nitrogen (42.9 %), ammoniacal nitrogen (50.3 %), and chemical oxygen demand (20.5 %), were observed in the second stage of VFCW without aeration and with plant. Nitrate and phosphorus levels increased during the experiment, likely due to microbial activity within the substrate and plant root zones. The final goal is to treat the piggery wastewater from a rural farm in India, produce electricity (by a Microbial Fuel Cell), to generate an effluent suitable for microalgae cultivation, with the produced biomass intended for use either as a biostimulant to enhance cereal crops included in pig diets or as a direct nutritional supplement in pig feed
Exams under pressure: analysis of metamorphism questions in the Biology and Geology National Final Exams
No full textRESUMO: A finalização da disciplina bienal de Biologia e Geologia (BG) pressupõe um exame final nacional (EFN) no 11º ano de escolaridade, que pode constituir um requisito de acesso ao ensino superior. Neste estudo, pretende-se compreender o peso atribuído à temática “metamorfismo e rochas metamórficas”, nos EFN da disciplina de BG da 1.ª e 2.ª fases, entre 2006-2021, e analisar a tipologia dessas questões. Foram analisadas 493 questões de Geologia de 32 EFN, tendo-se quantificado as questões com a temática em estudo (42) e avaliou-se a sua tipologia. Analisados os dados, constatou-se uma representatividade variável entre 5,0% (2020) e 33,3% (2013) na 1.ª fase e entre 5,9% (2016) e 20,0% (2009) na 2.ª fase, o que sublinha a importância conferida a esta temática nos EFN. As questões de escolha múltipla predominam tanto nas provas da 1.ª (34,1%) como da 2.ª fase (27,3%), não se constatando uma distribuição equitativa quanto à tipologia dessas questões.ABSTRACT: The completion of the biennial Biology and Geology (BG) subject presupposes a national final exam (EFN) in the 11th year of schooling, which can be a requirement for access to higher education. This study aims to understand the weight attributed to the theme “metamorphism and metamorphic rocks”, in the 1st and 2nd phases BG NFE, between 2006-2021 of the, and analyze the typology of these questions. A total of 493 Geology questions from 32 NGTs were analyzed. The questions related to the topic under study (42 questions) were quantified and their typology was evaluated. The representation varies between 5.0% (2020) and 33.3% (2013) in the
1st phase and between 5.9% (2016) and 20.0% (2009) in the 2nd,which underlines the importance given to this subject in this NFE. Multiple choice questions predominate in both the 1st (34,1%) and 2nd phase (27,3%), without an even distribution of the type of question