Repositório do LNEG

National Laboratory of Energy and Geology Scientific Repository

Welcome to LNEG’s Scientific Repository

The LNEG’s Scientific Repository intends to preserve, disseminate and give access to LNEG's scientific production in digital format.

The objectives of the Repository are: to increase the visibility and impact of the research carried out at LNEG, to improve internal and external communication and to preserve the institution's intellectual memory.

Email repositorio@lneg.pt

Recent Submissions

Exploring photozincographic metal plates collections: Manufacturing techniques and zinc corrosion

Publication . Ioaneș, Alexandra; Roldão, Élia; Cunha Diamantino, Teresa; Tissot, Isabel

ABSTRACT: 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.

2025-09Conference object

Open access

Dielectric UV filters for protection of fire-resistant glass based on intumescent layers

Publication . Silva, Ricardo Magno Lopes; Hashim, Hurraira; Roy, Deepto; Oliveira Fernandes, Carolina; Oliveira, Kevin; Leitão Pinheiro, Xavier Alexandre; Esteves, M. Alexandra; Capelo, Anabela; Donato, Mariana; Oliveira, Fernando; Ferreira, Cristina; Alves, Isabel N.; Cunha Diamantino, Teresa; Barreiros, Maria Alexandra; Rocha, Jorge; Passos Teixeira, Jennifer; Salomé, Pedro

ABSTRACT: Structures such as OLEDs, perovskite solar cells, intumescent glasses, and other components in modern devices and buildings contain materials suscep-tible to degradation when exposed to UV radiation, requiring protection to with-stand outdoor environmental conditions. In this work, multilayer coating config-ured as a Bragg Reflector on glass is employed as spectral filtering to protect the intumescent component of fire-resistant glass from degradation due to prolonged UV solar radiation exposure. By alternating low-n (SiO2)/high-n (TiO2) dielectric layers through spin-coating, precise control over film thickness could be achieved, allowing the fabrication of thin (<700 nm) UV filters with high trans-mission of visible sunlight – 88% of the 780 to 380 nm wavelength range – while reflecting almost all the incident UV – 90% of the wavelength below 380nm. Using relatively simple techniques, high precision coating was successfully achieved, resulting in an effective UV radiation protective barrier applied to en-hance the durability of the components in fire-resistant glass.

2025-06Conference object

Open access

Protection of Steel Structures against Fire and Corrosion by Paint Coatings: A comparative study

Publication . Ferreira, Cristina; Gonçalves, Rita; Alves, Isabel N.; Vieira, Ana; Donato, Mariana; Morgado, Vanessa; Silva, Helena; Cristino, Ana Filipa Russo de Albuquerque; Nunes Soares, Tiago Diogo; Barreiros, Maria Alexandra; Cunha Diamantino, Teresa

ABSTRACT: Steel structural systems in modular construction must be protected against corrosion and fire exposure. The durability of both protective properties plays a key role in ensuring long-term service life and minimizing maintenance costs. The present work aims to validate anticorrosive protection systems for steel structures, with and without fire protection properties, evaluating degradation mechanisms and assessing the compatibility of intumescent layers with anticor-rosive coatings, in terms of their impact on corrosion resistance and fire protec-tion properties.

2025-06Conference object

Open access

New SPEEK Membranes Modified with Bisphophonate Dopants [Resumo]

Publication . Teixeira, Fatima; Teixeira, António Paulo Silva; Rangel, Carmen M.

ABSTRACT: ustainable emerging energy technologies are pivotal to a decarbonized society that still continuously increases its energy demands. Fuel cells and eletrolyzers are part of these promising sustainable technologies, but they still depend on several factors, especially on their membranes. These are a key component acting as a separator, between their different materials and electrolytes of different devices' compartments, and as a selective ion-exchange barrier, controlling the ion flow and species permeability. Sulfonated poly(etheretherketone) (SPEEK) polymer is a versatile non-fluorinated alternative, as a low-cost and more environmentally friendly membrane, to the most commercially successful membrane based on the perfluorinated sulfonic Nafion®. Also, our previous studies showed that the incorporation of BPs dopants into the polymeric matrices, modifies the properties of the doped membranes, including their proton conduction and durability.

2025-09Conference object

Open access

Arquivo de lâminas e superfícies polidas do LNEG, uma coleção de valor científico nacional: LAMINOTECA 1.0 do LNEG

Publication . Pereira, Zélia; Quental, Lídia; Jorge, Micael; Teixeira, Rui; Patinha, Pedro; Xavier Matos, João Manuel; Mesquita Soares, Sofia; Silva Mendes, Márcia Cristina; Pereira, Aurete; de Oliveira, Daniel Pipa Soares; Matos, Luísa; Carvalho, Cristina Isabel Paulo; Dias, Ruben

RESUMO: O arquivo histórico do Laboratório Nacional de Energia e Geologia (LNEG) engloba um espólio científico resultante de quase 180 anos de atividade geológica e mineira, o que constitui um banco de dados excecional e um verdadeiro repositório geológico nacional. No âmbito das áreas de missão do LNEG, consta a preservação, tratamento e disponibilização deste património único. Este espólio é considerado património científico nacional, com significado histórico e fundamental à investigação estratégica do país e de enorme valor económico. Todavia, é pois, necessário que as coleções existentes se encontrem devidamente organizadas e preparadas para serem disponibilizadas online através da plataforma geoPortal da Energia e Geologia (GEG), infraestrutura online do LNEG. E, para a concretizar este objetivo, será necessário criar e desenvolver um centro de dados digital sobre coleções especificas, que facilite e promova a consulta da informação existente. O projeto LAMINOTECA 1.0 visa estabelecer um novo modelo de organização e valorização do espólio histórico do LNEG, parte integrante do repositório geológico nacional. Paralelamente, promove o reforço funcional do GEG, enquanto plataforma digital central institucional e de acesso público, para disponibilização estruturada e georreferenciada das coleções temáticas, com destaque para as geológicas e mineiras. Esta iniciativa facilitará a pesquisa e consulta especializada, contribuindo para o avanço científico, educativo e económico. Espera-se que este projeto apoie, no futuro, atividades de I&D aplicadas às áreas estratégicas do LNEG, nomeadamente o Plano Nacional de Cartografia e o Plano Nacional de Prospeção no âmbito do Ato das Matérias Primas Críticas, reconhecendo o valor económico e territorial do conhecimento geológico e fomentando a especialização inteligente em petrografia, paleontologia e mineralizações.

2025-10Technical report

Open access