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Tin-bearing granites from the Santa Comba de Rossas area, northern Portugal
No full textRESUMO: Na região de Santa Comba de Rossas aflora um complexo granítico (G1-G3) que se instalou durante os estágios sin-cinemáticos da Orogenia Varisca, há 317,9 ± 8,7 Ma (datação Rb-Sr de rocha total). Os granitos são intrusivos em metassedimentos de idade silúrica, do Domínio Parautóctone da Zona da Galiza – Trás-os-Montes, instalando-se no núcleo de uma antiforma NW-SE, resultante das fases de deformação D1 e D3, apresentando evidências de uma deformação em regime dúctil e frágil. Os dados geoquímicos e isotópicos sugerem que o granito G1, com biotite > moscovite e o granito G3, com biotite ≈ moscovite, correspondem a pulsos magmáticos distintos, que terão resultado da fusão parcial de materiais metassedimentares e sofrido uma diferenciação por cristalização fraccionada. Este processo foi responsável pelo aumento do teor de Sn naqueles granitos e, muito provavelmente, pela ocorrência do granito moscovítico G2, o mais rico em Sn (77 ppm), no exocontacto do plutão granítico G1.ABSTRACT: In the Santa Comba de Rossas area, a granitic complex (G1-G3) was emplaced during the syn-kinematic stages of the Variscan Orogeny, at 317.9 ± 8.7 Ma, as determined by whole rock Rb-Sr dating. The complex is intrusive on Silurian metasediments, from the Parauthocthonous Domain of Galicia – Trás-os-Montes Zone, in a NW-SE trending antiform formed during the D1 and D3 deformation phases and was itself affected by ductile and brittle deformation. Geochemical and isotopic characteristics suggest that the biotite > muscovite granite G1 and the biotite ≈ muscovite granite G3 correspond to distinct pulses of magma formed by partial melting of metasedimentary materials that subsequently evolved by fractional crystallization. This process was responsible for the increase in Sn content in those granites and, most probably, for the occurrence of the G2 muscovite granite, the richest in Sn (77 ppm), in the exocontact of the G1 granite pluton
Design optimisation of five pilot-scale two-stage vertical flow-constructed wetlands for piggery wastewater treatment
No full textABSTRACT: With growing pig farming, sustainable piggery wastewater treatment methods are essential for environmental protection. This study evaluated five pilot-scale two-stage vertical flow-constructed wetlands (VFCWs) with varying configurations of aeration, plantation, and saturation zones. Three VFCW configurations (1VFCW, 2VFCW, and 3VFCW) were unsaturated, while 4VFCW and 5VFCW were saturated in the second stage (up to 60 and 90 cm, respectively). The 5VFCW featured a stacked configuration with no space between its two stages. Passive aeration was selectively applied in 2VFCW, 3VFCW, 4VFCW, and 5VFCW, while plants were present in most configurations except the control. Saturated 4VFCW achieved the highest removal efficiency for TN (77.03 ± 16.24%) and NO3− (46.06 ± 45.96%), while the stacked 5VFCW showed the highest removal for chemical oxygen demand (COD) (94.17 ± 4.85%) and Total ammoniacal nitrogen (TOC) (86.35 ± 6.78%). Unsaturated 1VFCW excelled in TAN removal (98.89 ± 0.33%), and the control system (C) showed the highest removal efficiency for PO43− (90.38 ± 6.52%) and TOC (87.52 ± 9.83%). Overall, 4VFCW emerged as the most balanced and effective system, supported by an optimal combination of aerobic and anaerobic conditions that facilitated sequential nitrification and denitrification, along with an extended hydraulic retention time due to saturation
Exposure to ionizing radiation and dangerous substances inside buildings related to construction products
No full textABSTRACT: The use of many materials of geological origin and recycled materials in the construction of buildings faces an increasing demand and stricter regulation for quality control. Construction products are requested to meet safety standards including those for radon exhalation and gamma radiation emission, amongst other dangerous substances, because if unchecked they could deteriorate the quality and safety of the indoor environment. Construction products shall pass testing for radioactivity in order to meet those standards and to maintain a high ranking position in the international markets.N/
Avaliação da diversidade geomorfológica de Portugal Continental
No full textABSTRACT: 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.RESUMO: Apresentam-se os resultados da avaliação de diversidade, riqueza e equidade geomorfológica de Portugal continental, baseada em 4 níveis hierárquicos de unidades geomorfológicas de Portugal Continental. Os índices foram calculados numa grelha analítica hexagonal, testando-se oito dimensões de células (1 km, 2 km, 5 km, 10 km, 15 km, 20 km, 25 km e 30 km). A dimensão de 10 km forneceu uma definição mais clara das especificidades geomorfológicas regionais, as quais correspondem às áreas de maior diversidade e riqueza. Os resultados relativos à equidade não permitiram estabelecer relações tão claras com as unidades geomorfológicas. Os índices de diversidade e equidade, juntamente com a riqueza, fornecem uma avaliação mais abrangente da diversidade espacial. Estes resultados fazem parte da avaliação da geodiversidade de Portugal e são fundamentais para análises comparativas entre os vários elementos da geodiversidade e com outros elementos naturais e culturais
Caracterização de águas salinas da Ria de Aveiro (Portugal) para potencial uso em tratamentos de SPA
No full textABSTRACT: This study aims to characterize the properties of the saline waters from an old saltpan at the Ria de Aveiro, and assess its potential use in skin treatments. Eight water samples were collected from two different areas of an open-air salt SPA, during four different climatic seasons between 2020 and 2021. Physichochemical parameters of the waters revealed an alkaline pH and high electrical conductivity (EC), mainly in the area where salt production takes place (Area 2). Chemical analysis revealead an enrichment in potentially toxic elements (PTEs), namely Cu and Cr6+, in samples of Area 2, collected in the summer. MEV-EDE analysis of the total suspended matter (TSM) showed the presence of NaCl cubic particles, microorganisms (e.g., diatoms) and particles enriched in PTEs. The low concentrations of PTEs does not pose a risk to SPA users, allowing these waters to be used as a liquid phase in SPA treatments for skin diseases.RESUMO: O presente estudo tem como objetivo caracterizar as propriedades de águas salinas de uma antiga salina da Ria de Aveiro e avaliar o seu potencial uso em tratamentos de pele. Foram colhidas oito amostras de água em duas áreas distintas de um SPA salino ao ar livre, em quatro diferentes estações climáticas, entre 2020 e 2021. Os parâmetros físico-químicos da água revelaram um pH alcalino e elevada condutividade elétrica (CE), principalmente na área onde ocorre a produção de sal (Área 2). A análise química revelou um enriquecimento em elementos potencialmente tóxicos (EPTs), nomeadamente Cu and Cr6+, em amostras da Área 2, colhidas no verão. A análise do material total em suspensão (MTS) por SEM-EDS revelou a presença de partículas cúbicas de NaCl, microorganismos e partículas enriquecidas em EPTs. As baixas concentrações de EPTs não representaram qualquer risco para os utilizadores do SPA, permitindo a utilização destas águas como fase líquida em tratamentos de doenças de pele, em SPA
Chemical and Mineralogical Characterization ofWaste from Abandoned Copper and Manganese Mines in the Iberian Pyrite Belt, Portugal: A First Step Towards the Waste-to-Value Recycling Process
No full textABSTRACT: This study examines the chemical and mineralogical composition of waste materials from abandoned copper and manganese mines in the Iberian Pyrite Belt, Portugal, as a first step toward their potential recycling for critical and strategic raw materials (CRM and SRM). Using portable X-ray fluorescence (pXRF) and other analytical techniques, this research highlights the presence of valuable elements, including copper, manganese, and rare earth elements, in concentrations significantly above their crustal abundance. The findings underscore the dual potential of these wastes: as sources of secondary raw materials and for mitigating environmental hazards such as acid mine drainage (AMD).
Recovered materials include chalcopyrite, pyrolusite, and rhodochrosite, with critical elements like cobalt, lithium, and tungsten identified. pXRF proved to be a reliable, cost effective tool for rapid field and laboratory analyses, demonstrating high precision and good correlation with standard laboratory methods. The study emphasizes the importance of characterizing historical mining waste to support a circular economy, reduce reliance on foreign material imports, and address environmental challenges. This approach aligns with the European Union’s Critical Raw Materials Act, promoting sustainable resource use and the recovery of strategic resources from historical mining sites
Advancing Sustainable Production of High-Performance Cellulose Pulps
No full textABSTRACT: Highlights What are the main findings? Enzymatic hydrolysis pretreatment of industrial pulps Pulp composition influencing the enzymatic performance Enhanced conditions for high-performance cellulose pulps What is the implication of the main finding? Sustainable methodology to produce cellulose pulps Lower environmental impact and alignment with circular economic principles Improvements in tensile strength, air permeability, hydrophobicity, and internal bondingHighlights What are the main findings? Enzymatic hydrolysis pretreatment of industrial pulps Pulp composition influencing the enzymatic performance Enhanced conditions for high-performance cellulose pulps What is the implication of the main finding? Sustainable methodology to produce cellulose pulps Lower environmental impact and alignment with circular economic principles Improvements in tensile strength, air permeability, hydrophobicity, and internal bondingAbstract With a growing demand for renewable resources in high-performance materials, sustainable methods are preferred for their lower environmental impact and alignment with circular economy principles. Among these, enzymatic hydrolysis remains relatively underexplored yet shows strong potential for cellulose fibrillation, offering a promising route that may lower energy requirements by minimizing the need for extensive refining compared to conventional mechanical or chemical approaches. In this study, enzyme cocktails rich in cellulase and xylanase were applied to three industrial pulps, sulphite, bleached Kraft eucalyptus and thermomechanical pine, to produce high-performance cellulose pulps. Treatments were carried out using varying enzyme loads (5-40 filter paper units per gram of dry pulp, FPU/gdp) and reaction times (1-16 h). The resulting chemical composition, structural morphology, and physical-mechanical properties were systematically evaluated. The findings revealed that pulp composition strongly influenced enzymatic treatment, affecting surface fibrillation, fibre aggregation, swelling, and fibre shortening. Under optimized conditions, enzymatic pretreatment significantly enhanced paper performance, with improvements in tensile strength, air permeability, hydrophobicity, and internal bonding. Overall, enzymatic hydrolysis represents a sustainable solution and a strategy which could reduce energy expenditures to high-performance cellulose pulps, suitable as reinforcing fibres in packaging applications
Oceans and continents: at the end of the 15th and 20th centuries, and the beginning of the 21st
No full textRESUMO: Durante os séculos XV e XVI, os descobridores portugueses substituíram a geografia Mediterrânica pela Atlântica. De algum modo, é possível estabelecer um paralelo com a perspetiva atual da Tectónica de Placas Macias, em que a litosfera oceânica arrasta a litosfera rígida dos escudos pré-câmbricos.ABSTRACT: During the 15th and 16th centuries, the Portuguese discoverers replaced the Mediterranean geography by the Atlantic geography. To some extent, a parallel can be drawn with the modern perspective of Soft Plate Tectonics, where a soft oceanic lithosphere drags the rigid shield lithosphere
Influence of Cr on the quaternary FeTaTiW medium entropy alloy
No full textABSTRACT: The search for advanced materials has been growing, and high entropy alloys (HEAs) are emerging as promising candidates for application in the fusion domain. This work investigates the effect of Cr on the FeTaTiW medium entropy alloy to form (CrFeTaTi)70W30 high entropy alloy, comparing the experimental production and characterization with the simulation (molecular dynamics and hybrid molecular dynamics-Monte Carlo) of the phases formed. The alloys were produced by mechanical alloying and sintered by spark plasma sintering. Both simulations have shown that a body-centered cubic structure is formed for both compositions. Monte Carlo simulation provides a more precise prediction of microstructural formation and element segregation. Microstructural examination of the consolidated material revealed the presence of a W-rich phase and a Ti-rich phase, consistent with the phase separation observed in the MC simulations. Moreover, X-ray diffraction analysis of the milled powder for FeTaTiW and (CrFeTaTi)70W30 confirmed the formation of a bcc (body-centered cubic)-type structure with a low fraction of intermetallic phases. Mechanical testing showed ductile behavior at 1000 degrees C where (CrFeTaTi)70W30 showed a stress magnitude almost double that of FeTaTiW. Additionally, the thermal diffusivity between 20 and 1000 degrees C of both alloys increases as the temperature rises. (CrFeTaTi)70W30 exhibits an increase from 3 to 5 mm2/s, while FeTaTiW increases from 4 to 9 mm2/s. Still, both system's thermal diffusivity values are lower than those of CuCrZr and pure tungsten. Despite this, the study underscores the promising attributes of HEAs and highlights areas for further optimization to enhance its suitability for extreme conditions
Transição Ordovícico-Silúrico na Zona Centro-Ibérica: Apenas um contacto estratigráfico ou um elemento estruturante do Varisco Ibérico?
No full textABSTRACT: The Ordovician-Silurian boundary in the Central-Iberian Zone is often considered a normal stratigraphic transition. Nevertheless, in studies carried out in Portugal (e.g. Espinhosela, São Mamede and Buçaco areas) and Spain (e.g. Alcañices Synform) this contact is marked by the development of shear zones subparallel to the lithostratigraphic units. Ongoing structural mapping in Celorico de Basto (Marão region) shows that near Campanhó, the Ordovician (Pardelhas Formation) and the Silurian (Campanhó Formation) units are bounded by a regional shear zone with a normal kinematics (the Covelo do Monte Fault, here presented). Although their origin is debatable, the intraorogenic normal faults are common mechanisms active during Variscan times in the Central-Iberian Zone. In the case of the Ordovician-Silurian boundary, these detachments could be facilitated by shale and organic materials prone to control the development of shear zones.RESUMO: O limite Ordovícico-Silúrico na Zona Centro-Ibérica é frequentemente considerado uma transição estratigráfica normal. No entanto, estudos realizados em Portugal (e.g. áreas de Espinhosela, São Mamede e Buçaco) e Espanha (e.g. Sinforma de Alcañices), mostram que este contato é frequentemente marcado pelo desenvolvimento de zonas de cisalhamento subparalelas às unidades litostratigráficas. Cartografia estrutural de pormenor em curso em Celorico de Basto (região do Marão) mostram que, próximo a Campanhó, as unidades do Ordovícico (Formação de Pardelhas) e do Silúrico (Formação de Campanhó) são limitadas por uma falha normal (a Falha de Covelo do Monte, aqui apresentada). Embora a sua génese seja controversa, a instalação de falhas normais intra-orogénicas é um mecanismo comum ativo durante o orógeno Varisco na Zona Centro-Ibérica. No caso do contacto Ordovícico-Silúrico, estas falhas parecem ter sido controladas por material
orgânico e argiloso suscetível de desenvolver superfícies de descolamento