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Geochemical and Sr-Nd isotope constraints on the provenance of Permian deposits from Mozambique's Lower Karoo Zambezi Basin
Publication . Jorge, Raul C. G. Santos; Fernandes, Paulo; Pereira, Zélia; Santos, José Francisco; Lopes, Gilda; Marques, João
ABSTRACT: Whole-rock geochemistry and Sr-Nd isotopic compositions of Permian mudrocks from the Moatize and Matinde formations were analysed to constrain the sediment provenance, weathering history and palaeogeographic setting of the Moatize - Minjova Sub-Basin in the Karoo Zambezi Basin of Mozambique. The geochemical signatures of both formations suggest minimal effects of recycling and sorting, and point to rapid sediment deposition within an active tectonic setting. Trace element systematics and key provenance ratios (Th/Sc, La/Sc, Cr/Th, La-N/Sm-N,Sm- Eu/Eu & lowast;) indicate heterogeneous source areas dominated by felsic rocks with a minor mafic contribution. The mudrocks of the Moatize and Matinde formations exhibit similar isotopic signatures, with epsilon Nd (t) values of -9.32 +/- 0.74 and -7.99 +/- 1.10, and Nd T-DM model ages of 1.68 +/- 0.08 and 1.51 +/- 0.12 Ga, respectively. These isotopic signatures indicate that both formations were derived from mixed sources, including late Mesoproterozoic and Neoproterozoic rocks from southern Malawi, the Nampula Block (a subdomain of southernmost Malawi), the Guro Suite and the Macossa-Chimoio Nappe. Both Moatize and Matinde mudrocks exhibit high Chemical Index of Alteration (>85) and Chemical Index of Weathering (>90) values, along with low Index of Compositional Variability and low K/Cs ratios. The Al2O3-(CaO + Na2O)-K2O (A-CN-K) relationships indicate that the Moatize and Matinde mudrocks have not undergone post-depositional K-metasomatism. The data collectively indicate intense palaeoweathering conditions in the source areas. Furthermore, the weathering indices suggest warm and humid palaeoclimate during the deposition of the Moatize and Matinde formations. These formations were deposited in a confined continental basin between the Guadalupian (middle Permian) and the Lopingian (late Permian).
Uncertainty-Aware Planning of EV Charging Infrastructure and Renewable Integration in Distribution Networks: A Review
Publication . Tripathy, Sasmita; Fahnbulleh, Edwin Boima; Ghatak, Sriparna Roy; Lopes, Fernando; Acharjee, Parimal
ABSTRACT: Transitioning from internal combustion engines to electric vehicles (EVs) is critical for fighting climate change. This requires widespread adoption of Electric Vehicle Charging Stations (EVCSs). Integrating EVCSs and renewable energy sources (RESs) into distribution networks (DNs) is vital for a sustainable transportation system while enhancing power generation in an environmentally friendly manner. This review explores challenges and opportunities of EVCS and RES integration, concentrating on EV charging-demand uncertainty modeling, forecasting algorithms, planning techniques, and the impacts on DN. It discusses forecasting algorithms in terms of learning-based and non-learning-based methods. EVCS planning algorithms are also discussed, involving deterministic and stochastic methods. The technical, environmental, reliability, and economic impacts of EVCS-RES on DNs are discussed. It explores optimization strategies to minimize these impacts, incorporating them as objective functions. Additionally, the survey examines the methods of incorporating EVs and RES in DN, optimizing EVCS allocation while addressing EVCS impacts on voltage regulation, power loss, and network reliability. The importance of energy management systems and advanced forecasting techniques in balancing power fluctuation and improving efficiency is emphasized. Finally, it identifies open problems and future directions for forecasting and optimizing EVCS-RES integration in the networks. These findings are highly relevant for designing resilient and efficient modern power systems that leverage RES and EVCS in the grids.
CrFeVWX (X = Ta or Ti) High-Entropy Alloy: A Theoretical and Experimental Comparative Investigation on Phase Stability
Publication . Martins, Ricardo; Valadares, Vasco; Pereira, André; Pereira Gonçalves, Antonio; Neves, Filipe; Sá, Ana; Luz, Paulo P. da; Monteiro, Bernardo; Galatanu, Andrei; Monnier, Judith; Villeroy, Benjamin; Dias, Marta
ABSTRACT: Materials capable of withstanding extreme environments open promising opportunities for nuclear fusion reactors. In this study, equiatomic CrFeTaVW and CrFeTiVW high-entropy alloys are investigated as interlayer materials between W and CuCrZr. Monte Carlo and Molecular Dynamics simulations predicted a bcc-type structure for both systems. Additionally, the Monte Carlo simulation predicts lower potential energy and a more stable structure for both systems than Molecular Dynamics. For CrFeTaVW, the chemical segregation values are lower in MC than in the MD simulation, whereas for CrFeTiVW, the opposite trend is observed, with MC indicating stronger segregation values. After simulation, the high-entropy alloys were prepared by planetary ball milling, consolidated by spark plasma sintering, and analyzed using X-ray diffraction, scanning electron microscopy, and thermal diffusivity. The experimental results for the milled powders confirmed the formation of a bcc structure in both alloys. The consolidated material revealed a bcc-type structure and an Fe2Ta Laves phase for the CrFeTaVW HEA, while the CrFeTiVW HEA exhibits two different bcc-type structures. The values of CrFeTaVW and CrFeTiVW thermal diffusivity are between 3.5 and 7 mm2/s, which is consistent with the expected values for high-entropy alloys. Overall, the findings indicate that these HEAs have promising properties that can be used in extreme environments.
Estudos de Geologia e Energia via deteção remota no LNEG [Comunicação oral]
Publication . Quental, Lídia; Simões, Teresa; Gonçalves, Pedro; Couto, António; Costa, Paula Silva; Nave, Silvia; Carvalho, João; de Oliveira, Daniel Pipa Soares; Simoes, Sofia; Patinha, Pedro; Dias, Ruben; Justino, Paulo Alexandre
Stakeholder views of land conflicts in utility-scale solar energy: toward a spatial assessment tool
Publication . Alves, André; Simoes, Sofia
ABSTRACT: Renewable energy sources (RESs) power plants, particularly solar photovoltaic (PV) infrastructure, are being deployed at an unprecedented scale to allow the transition to carbon neutrality. Rapid expansion of PV facilities cannot proceed without careful consideration of spatial planning and environmental impacts. Although social acceptance of RES is generally high, there is little consensus on where such plants should be located, as stakeholders perceive their impacts in diverse and often conflicting ways. This study aimed to (i) assess the spatial distribution of planned utility-scale solar power plants (SPP) in Portugal in relation to environmentally and culturally sensitive areas; (ii) analyse stakeholder perceptions of SPP impacts across different land uses and territorial settings; and (iii) develop an impact index that incorporates stakeholder information to classify PV projects by degree of impact. An online survey was conducted to examine perceived impacts associated with SPP development, and a classification methodology was designed using an additive aggregation method to produce a geographic information system-based index to classify projects. The questionnaire answers reveal substantial heterogeneity in individual preferences but also indicate intragroup convergence and intergroup divergence among stakeholder groups. The impact index provides a framework for classifying land-use conflicts related to large-scale solar projects and enables preliminary assessment of planned developments in relation to stakeholder alignment. These findings contribute to spatial energy planning by demonstrating how stakeholder perceptions of land-related impacts can be operationalised to inform siting decisions for RES plants.