Repositório do LNEG
National Laboratory of Energy and Geology Scientific Repository
Recent Submissions
Towards climate adaptation: a case study of a Coastal City in Portugal
Publication . Aelenei, Laura Elena; Viana, Susana; Simões, Teresa; Amorim, Filipa; Simoes, Sofia; Barbosa, Juliana Pacheco; Justino, Paulo Alexandre; Goncalves, Helder; Dinis, J.; Fernandes, G.
ABSTRACT: The present study focuses on the use of complementary numerical tools to support the development of a climate neutrality roadmap for Cascais, a coastal Portuguese city and one of the nine pilot cities in the Re-Value project. The results contribute to refining the roadmap and updating Cascais' long-term Territorial Transformation Plans to accelerate its journey to climate neutrality by 2050. For this, a spatial analysis was conducted to assess the potential for rooftop solar PV, onshore wind energy, and wave energy along the coastline. Additionally, an innovative and simplified Decision Support Tool (DST) was developed to support municipalities in the development of their climate neutrality roadmaps and was used in the design of the scenarios and trajectories, which are now being integrated into the climate neutrality roadmap for Cascais. The DST tool results show that in the High Development scenario, when compared with the reference year of 2019, the total final energy demand can decrease by 7.2 % in 2050 due to the implementation of energy efficiency measures following the concept "Energy Efficiency First" and along with the increase of electrification, the introduction of hydrogen in the transport sector, and a broader implementation of renewable energy in the urban fabric and public spaces, Green House Gas (GHG) emissions can decrease by 82 % in 2050.
Comparison of the corrosion of ferritic and austenitic stainless steel (AISI 430 and AISI 316L) with LiNaK carbonate salts for thermal energy storage in CSP/CST applications
Publication . Gil, Mafalda; Pedrosa, Fátima; Paiva Luís, Teresa; Figueira Vasques, Isabel; Oliveira, Fernando; Cunha Diamantino, Teresa
ABSTRACT: This study focuses on the corrosion rates and mechanisms of two stainless steels, austenitic AISI 316L and ferritic AISI 430, in contact with a eutectic mixture of LiNaK carbonates in long-term tests at 650 degrees C. The selection of these two stainless steels was based on their differences, both in their intrinsic characteristics and in the cost associated with each one. The research also underscores the importance of optimizing the descaling methods used to evaluate the corrosion rate. Corrosion rates were measured gravimetrically according to ISO 17245:2015, revealing an asymptotic behavior for both steels, with AISI 430 with a corrosion rate of 237 f 21 mu m and AISI 316L of 151 f 13 mu m after 2000 h of testing. Corrosion mechanisms were analyzed using SEM/EDS, GDOES, and XRD techniques, which identified well-defined oxide layers with varying compositions. Given the observed corrosion mechanisms and its lower cost, AISI 430 steel seems to have great applicability in CSP/CST plants, provided it is paired with an appropriate protective coating.
Zeolites and associated minerals as indicators of post-magmatic hydrothermal alteration in Mesozoic tholeiitic basalts in Northeastern Brazil
Publication . Araujo, Lidyane; Castro Jobim Vilalva, Frederico; Franco de Souza, Raquel; Bustamante, Andres; Souza, Laécio
ABSTRACT: In northeastern Brazil, tholeiitic basalts and microgabbros from the Rio Ceará-Mirim dike swarm and Serra do Cuó basaltic flow experienced post-magmatic hydrothermal alteration, forming secondary minerals that replaced magmatic phases and filled amygdules. Petrographic, X-ray diffraction, thermogravimetric, and chemical analyses identified laumontite, quartz, and calcite as the dominant amygdule minerals in the Rio Ceará-Mirim dikes, formed at temperatures < 150 °C (Stage II) following an earlier low to moderate-temperature (< 150 – 200 ºC) alteration phase (Stage I). In the Serra do Cuó basalts, polymineralic amygdule formation began with mafic phyllosilicates (from < 150 to ~200 °C, Stage I) and proceeded to Ca-Na zeolites (~250 °C, Stage II). These assemblages reflect fluid composition changes due to primary mineral destabilization by heated meteoric fluids. Results indicate fluid composition, rather than temperature, as the primary control on mineral variability, highlighting the role of host-rock chemistry in hydrothermal alteration.
Oceanos e continentes: no fim dos séculos XV e XX, e no início do século XXI
Publication . Ribeiro, António
RESUMO: 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.
Cartografía Geológica del Plan Nacional de Geología de Angola (PLANAGEO)
Publication . Merino-Martínez, E.; Rodrigues, José Feliciano; Martín-Banda, Raquel; Francés, Alain Pascal; Feria, María Carmen; López-Bahut, T.; Ferreira, Ezequiel; García-Lobón, J. L.; Gumiel, J. C.; Cuervo, I.; Victorino, Américo da Mata; Manuel, José
RESUMEN: La cartografía geológica fue la actividad central en la que se basó el Plan Nacional de Geología de Angola (PLANAGEO). Los trabajos de cartografía geológica realizados por el consorcio UTE PLANAGEO (IGME/LNEG/IIA) en el sur de Angola (476.512 km2), desarrollados entre 2016 y 2020, comprendieron 44 cartas a escala 1:250.000, 15 cartas a escala 100.000, 8 mapas de síntesis a escala 1:500.000 y 4 mapas geotemáticos a escala 1:1.000.000. A partir de estos trabajos, fueron distinguidos diversos dominios geológicos en el sur del Escudo de Angola, delimitados por macroestructuras bien definidas en los modelos geofísicos. Los mapas y sus memorias asociadas reúnen todo el conocimiento generado durante PLANAGEO, siendo un manual de referencia geológica y un modelo para futuros estudios geológico-mineros. Los mapas geológicos realizados constituyen la base de una infraestructura regional de conocimiento geológico de la región sur de Angola, y proporcionan información básica para el aprovechamiento óptimo del territorio y desarrollar el potencial de los recursos naturales del país.