4161 research outputs found
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Thermochemical performance of ceria coated-macroporous 3D-printed black zirconia structures for solar CO/H2 fuels production
No full textABSTRACT: The use of macroporous structured ceria for the solar thermochemical splitting of CO2 and H2O to produce clean fuels through two-step redox cycles was investigated. The research aimed to assess the reactivity of 3D-printed black zirconia gyroid structures coated with a microporous layer of pure CeO2 for producing CO and H2. Such porous designs are intended to increase both the absorption of solar radiation and the available surface area for the solid-gas reaction. It was observed that the structure degraded more at the top of the reactor cavity, where the formation of CexZr1-xO2 solid solutions occurred at the coating/substrate interface. Besides, the porous ceria structure remained after redox cycles in the samples not directly exposed to solar radiation. Consequently, the solar reactor achieved CO and H2 production rates of up to 5.4 and 1.9 mL min-1 g-1 with fuel yield over 0.2 mmol g-1, and the material maintained its performance over several consecutive cycles without any loss of reactivity. This indicates a strong potential for producing solar fuels at a large facility using custom 3D-printed ceria-coated structures
Foresighting Scenarios for Green Hydrogen in Portugal: Systematization of Potential Futures and Identification of Bottlenecks and Constraints
No full textABSTRACT: The use of green hydrogen has emerged as a promising avenue for facilitating the decarbonization of society. In this study, the potential futures of green hydrogen in Portugal, a key player in Europe's energy transition, are explored. Utilizing General Morphological Analysis combined with advanced clustering, the various political, social, and technological elements are analyzed to create a multifaceted view of the sector's future. This results in seven distinct scenario clusters, each offering unique insights into the challenges and opportunities for green hydrogen. The scenarios span a range of outcomes, from rapid growth fueled by strong policy support and technological advancements to more measured development due to economic or infrastructural hurdles. This study intends to provide stakeholders a deep understanding of the factors influencing green hydrogen's role in Portugal's push towards a sustainable energy landscape by 2030. These results provide a basis for the development of new projects and research directions, providing them with the necessary knowledge to make informed decisions. Moreover, this study will contribute to decision support by facilitating actions aimed at fostering the appropriate development of green hydrogen.The present research has been partially funded by Missão Interface-Centros de Tecnologia e Inovação (CTI)-Investimento RE‐C05‐i02-
N.° 03/C05‐i02/2022, under the Portuguese PRR, RE‐C05‐i02—N.°03/C05‐i02/2022
Exploring photozincographic metal plates collections: Manufacturing techniques and zinc corrosion
No full textABSTRACT: This study explores the materials, manufacturing processes, and corrosion behavior of photozincographic plates from the Lactário Museum in Lisbon, Portugal. Analysis of thirty-three historical plates (1927–1971) and three non-historical plates using stereomicroscopy, micro-X-ray fluorescence, X-ray diffraction, and accelerated aging tests revealed that the plates are primarily composed of zinc with trace elements (lead, iron, and calcium) and produced by distinct manufacturing techniques. Corrosion products containing sulfur-based compounds indicate the influence of an outdoor environment. Accelerated aging demonstrates significant image degradation from corrosion, highlighting the need for tailored preservation
strategies for these unique composite objects
Winds of change: the potential path disturbing effect induced by the offshore wind energy technology
No full textABSTRACT: Path development literature focus on path creation or on changes in mature paths but gives limited attention to early path evolution. The paper addresses this gap by investigating the disturbance, in the early trajectory of technology-driven regional industrial paths, that results from the emergence of new generations of technology. We propose that changes in actor composition and purposeful resource modification actions by path actors are important elements of disturbance and develop an approach to investigate their effects. The ongoing changes in the wind energy regional industrial path, associated with the development and diffusion of offshore wind energy technology, are empirically investigated. The research finds evidence of path disturbing effects at the level of actors and resources. As onshore wind actors start engaging in offshore activities and new actors enter the wind business, the composition and industrial structure of the wind energy regional path and its spatial distribution start to change. There are equally important effects upon the process of resource formation, at the level of knowledge, market, financial and legitimacy system resources and across the various phases of the industrial value chain. The paper contributes to a better understanding of path disturbance and offers an instrument to assess deviation in path trajectories and pinpoint its sources
Unconventional Three-Dimensional Active Seismic Tomography Applied in the Lousal Mine (Iberian Pyrite Belt, Portugal)
No full textABSTRACT: The Lousal Mine (Iberian Pyrite Belt, Portugal) was operated from 1900 to 1988 for the extraction of massive sulphides and was later rehabilitated as a science museum. It was selected as a test site for underground muon tomography applied to geophysical surveys, as part of the LouMu project. This study focuses on seismic tomography to analyse the subsurface above the mine gallery, primarily surveyed by a muography telescope, which was developed specifically for this site by the Laboratory of Instrumentation and Experimental Particle Physics. To validate the muon tomography results, an initial approach using conventional 2D seismic refraction failed to reach the Waldemar gallery depth, due to limited seismic ray coverage. Therefore, an innovative setup using surface shots and in-gallery geophones was implemented, providing full ray coverage. A 3D velocity model was then produced using the ATOM3D code, which enabled the integration of this configuration and performed travel-time inversion for velocity calculation. A regional dextral strike-slip fault, the Corona Fault (CF), crosses the surveyed area, and served as the main focus of this investigation. The 3D velocity model successfully detected this structure, that corresponded to the boundary between positive anomalies of the Volcano-Sedimentary Complex (VSC) and negative anomalies of the Phyllite-Quartzite Group (PQG). The absolute velocity distribution showed a distinct offset around the Corona Fault (CF), indicating a dextral strike-slip mechanism. A subvertical extension of secondary faults was observed, reflecting deformation similar to that of the main tectonic context. Previous data from the gallery confirmed that these results are consistent with the known geology and can serve as a reference for the muon tomography interpretations
EN 12440: A necessary review of the denomination criteria standard to elevate EU natural stone in a digital and sustainable market
No full textABSTRACT: The European standard EN 12440, which regulates the denomination of natural stones, is a vital strategic asset for the industry's competitiveness. However, its effectiveness has long been compromised by ambiguous criteria and a slow revision process. As the new Construction Products Regulation (CPR) and the introduction of Digital Product Passports (DPPs) make traceability and transparency mandatory, the shortcomings of the standard have become a critical liability. This paper presents a detailed analysis of EN 12440's deficiencies and, drawing on the work of a multidisciplinary technical group, outlines concrete proposals for its modernisation. The aim is to transform the standard into a robust and dynamic tool, enabling the natural stone sector to meet future regulatory, digital, and sustainability requirements
Ensuring Fairness in Global Energy Transition: The Role of the Eu Carbon Border Adjustment Mechanism
No full textABSTRACT: The European Union’s Carbon Border Adjustment Mechanism (CBAM), as part of the Fit for 55 package, introduces a carbon pricing policy for imports from carbon-intensive sectors to mitigate carbon leakage and level the playing field in global trade. This article analyses the potential of CBAM to promote fairness and transparency in climate policy, both within and beyond the EU. We examine its integration with the EU Emissions Trading System (EU ETS), analyses the complementarity of both systems, evaluate its Monitoring, Reporting and Verification (MRV) system, and present a multi-criteria regional comparison based on environmental, circular, and social standards. The steel sector serves as a case study to illustrate economic implications and the effectiveness of carbon pricing models. Our findings suggest that while CBAM can reduce emissions and encourage innovation, its fairness depends on careful implementation, support mechanisms for developing countries, and continuous alignment with international climate goals
Ranked Mappable Criteria for Magmatic Units: Systematization of the Ossa-Morena Zone Rift-Related Alkaline Bodies
No full textABSTRACT: The Ossa-Morena Zone (SW Iberian Massif) hosts the largest set of Cambro-Ordovician alkaline magmatic plutons related to the Palaeozoic rifting of the northern Gondwana margin so far described. An organized framework for their classification at different scales is proposed through data-driven ranks based on their distinctive petrological features relative to other rift-related magmatic rocks found throughout western Europe. The classification method aims to enhance geological mapping at different scales, regional- and continental-scale correlations, and, as such, facilitate the petrogenetic interpretation of this magmatism. The hierarchical scheme, from highest to lowest rank, is as follows: rank-1 (supersuite) assembles rocks that have distinctive characteristics from other magmatic units emplaced in the same magmatic event; rank-2 (suite) categorizes the units based on their major textural features, indicating if the body is plutonic, sub-volcanic, or a strongly deformed magmatic-derived unit; rank-3 (subsuite) clusters according to their spatial arrangement (magmatic centres) or association to larger structures (e.g., shear zones or alignments); rank-4, the fundamental mapping unit, characterizes the lithotype (alkaline granite, alkaline gabbro, syenite, albitite, etc.) by considering higher ranks (alkalinity and textural aspects); rank-5 characterizes the geometry of individual plutons (with several intrusions) or swarms; rank-6 (smallest mappable unit) corresponds to each intrusion or individual body from a swarm. Although this classification scheme is currently presented solely for the Ossa-Morena Zone, the scheme can be easily extended to incorporate other co-magmatic alkaline bodies, such as those in the NW Iberian allochthonous units or other peri-Gondwanan zones or massifs, in order to facilitate regional correlations of the rift-related magmatism
Systematic review on social acceptance of mining in the context of the energy transition
No full textABSTRACT: This technical report presents a systematic review of the scientific literature on the social acceptance of mining in the context of the energy transition. The analysis covered 118 publications from 1998 to 2025 in English, Portuguese, and Spanish, integrating quantitative and qualitative methods. The results show the growth of the field (7.47% per year) and reveal the following central factors for social acceptance: community participation, transparency, procedural justice, institutional trust, and conflict management. Regional differences were identified: in Europe, the emphasis falls on governance and transparency, whereas in Latin America socio-environmental justice, conflicts, and expectations prevail. Despite the centrality of critical minerals for the energy transition, few studies explicitly articulate both themes. The report proposes recommendations for policymakers, companies, and communities, aiming at more participatory practices. This is the first LNEG study on this topic, contributing to public policies and institutional strategies in the mining sector
Natural Stones from EU - Denomination Criteria Standard: A Review
No full textABSTRACT: Harmonization is vital in the European Union. It is mainly applied to materials, processes, products and services. However, it is also crucial for other domains. An example of this is the denomination of natural stones. It is important that denomination meets strict criteria to promote natural stone Market, as well as their products in the imperative new “Construction Products Regulation (CPR)”. This was the purpose behind the development and recent revision of EN 12440. However, the important role that was intended for this standard in the natural stone sector was never fully achieved, due to the vague and unobjective way in which the denomination criteria were laid down. This review aims to analyse the standard, pointing out what needs to be harmonized, and to present concrete proposals for its improvement, so that the standard can fully perform its purpose