Últimos itens adicionados do Acervo: Laboratório Nacional de Energia e Geologia

O Laboratório Nacional de Energia e Geologia (LNEG) é uma instituição de I&D orientada para responder às necessidades da sociedade e das empresas. Apostando numa investigação sustentável e para a sustentabilidade através da geração do conhecimento em Portugal.

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‣ Strain partitioning and westwards migration of deformation in NW Gulf of Cadiz (Africa-Iberia plate boundary)

Rosas, Filipe Medeiros; Duarte, João C.; Terrinha, Pedro; Vicente, J.; Matias, Luís; Valadares, Vasco; Duarte, Henrique; Roque, Ana Cristina
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em /04/2007 Português
European Geosciences Union General Assembly 2007 (EGU 2007), Vienna, Austria, 15-20 April 2007

‣ Deep Submarine Giant Scours in northern Gulf of Cadiz (offshore SW Iberia) : a singular case of sedimentary and tectonic coupling

Duarte, João C.; Rosas, Filipe Medeiros; Terrinha, Pedro; Valadares, Vasco; Taborda, Rui; Matias, Luís; Roque, Ana Cristina; Magalhães, Vítor Hugo; Henriet, Jean-Pierre; Pinheiro, Luís M.
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em /04/2007 Português
European Geosciences Union General Assembly 2007 (EGU 2007), Vienna, Austria, 15-20 April 2007

‣ New magnetic survey in the Tagus Abyssal Plain (TECTAP Project)

Moulin, M.; Afilhado, Alexandra; Terrinha, Pedro; Pinheiro, Luís M.; Lourenço, Nuno; Rosas, Filipe Medeiros; Matias, Luis; Neves, S.; Miranda, M.; Luís, J.; Cunha, Tiago A.; Alves, T.; Roque, Ana Cristina; Domingos, M.; Batista, Luís Filipe
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em /04/2009 Português
European Geosciences Union General Assembly 2009 (EGU 2009), Vienna, Austria, April 19-24, 2009

‣ Tectonic control and mass-wasting processes along S. Vicente Canyon (SW Iberia) : evidences from multibeam bathymetry and seismic reflection data

Valadares, Vasco; Roque, Ana Cristina; Terrinha, Pedro
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em /04/2009 Português
European Geosciences Union General Assembly 2009 (EGU 2009), Vienna, Austria, April 19-24, 2009

‣ Morphostructure of the Tore Seamount and evidences of recent tectonic activity (West Iberia Margin)

Roque, Ana Cristina; Terrinha, Pedro; Lourenço, Nuno; Abreu, M. Pinto de
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em /12/2009 Português

‣ Precipitation Maxima and upwelling trends at the NAO Southern Pole during the last millenium

Abrantes, Fátima; Rodrigues, Teresa; Montanari, B.; Santos, Célia Teresa; Voelker, Antje H. L.; Lopes, Cristina Isabel
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em /04/2009 Português
European Geosciences Union General Assembly 2009 (EGU 2009), Vienna, Austria, April 19-24, 2009

‣ Primary productivity evolution during the latest Holocene (2,000 yr) off Oporto (Portuguese Margin)

Abrantes, Fátima; Montanari, B.; Rodrigues, Teresa; Santos, Célia Teresa; Voelker, Antje H. L.
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em /04/2008 Português
European Geosciences Union General Assembly 2008 (EGU 2008), Vienna, Austria, April 13-18, 2008

‣ Millennial-scale deep ocean ventilation and sea-surface variability during the last four glacial cycles : a new assessment for the Northern Hemisphere ice-sheet growth

Rashid, H.; Gruetzner, J.; Lodestro, S.; Voelker, Antje H. L.; Flower, B. P.; Quinn, T. M.
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em /12/2007 Português
AGU Fall Meeting, S. Francisco (USA), 19-14 December 2007, Suppl., Abstract PP44B-07

‣ Surface and deep water variations during MIS 11-15 at IODP Site U1313 in the Mid-Latitude North Atlantic : insights into Mid-Pleistocene rapid climate change

Voelker, Antje H. L.; Abrantes, Fátima; Lebreiro, Susana
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em /12/2007 Português
AGU Fall Meeting, S. Francisco (USA), 19-14 December 2007

‣ Sedimentation and climatic processes on the Tagus River System (Portuguese Margin)

Abrantes, Fátima; Rodrigues, Teresa; Vis, Geert-Jan; Alt-Epping, Ulrich; Voelker, Antje H. L.; Gil, Isabelle M.; Lebreiro, Susana; Schneider, Ralph
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em /08/2007 Português
17th INQUA Congress in Cairns (Australia), 28th July to 3rd August, 2007

‣ Proxy calibration to instrumental dataset : implications for paleoceanographic reconstructions

Abrantes, Fátima; Rodrigues, Teresa; Lopes, Cristina Isabel; Gil, Isabelle M.; Bartels-Jónsdóttir, Helga Bára; Harris, Ian; Witt, Lynn; Grimalt, Joan O.
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em /08/2007 Português
17th INQUA Congress in Cairns (Australia), 28th July to 3rd August, 2007

‣ Detrital zircon geochronology of the Carboniferous Baixo Alentejo Flysch Group (South Portugal); constraints on the provenance and geodynamic evolution of the South Portuguese Zone

Rodrigues, B.; Chew, D. M.; Jorge, Raul C. G. Santos; Fernandes, P.; Pires, Cristina Veiga; Oliveira, José Tomás
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Artigo de Revista Científica
Publicado em /05/2015 Português
U–Pb detrital zircon data from the Baixo Alentejo Flysch Group in the South Portuguese Zone show significant age differences between formations. The Visean Mértola Formation and Serpukhovian to early Bashkirian Mira Formation are dominated by zircons in the 316–388?Ma age range, whereas the late Bashkirian to late Moscovian Brejeira Formation is dominated by zircons with an age range of 498–687?Ma. Detrital zircons spanning an age range of 0.9–1.1?Ga are present in the Brejeira Formation but are absent in the Mértola and Mira formations. Detrital zircon ages of the Mértola and Mira formations indicate provenance from an extra-basinal source (Ossa–Morena Zone) with a minor intra-basinal contribution (South Portuguese Zone). The abundant presence of detrital zircon with age ranges of 500–750 and 0.9–1.1?Ga in the Brejeira Formation suggests a sediment source from the Avalon–Meguma terranes with limited recycling from the SW Portugal Domain. The different inferred source areas for the Baixo Alentejo Flysch Group formations are attributed to the presence of a forebulge that was formed in Mid-Visean times during the foreland phase of the South Portuguese Zone. The forebulge acted as a physical barrier separating sub-basins that accumulated the Mértola–Mira and Brejeira sediments respectively.

‣ Earth observation contribution as a component for mineral resources systems

Quental, Lídia Maria; Oliveira, Daniel P. S.; Filipe, Augusto; Lopes, Catarina; Fortes, Carla
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em /05/2015 Português
Apresentação em Powerpoint com 24 diapositivos

‣ Earth observation contribution as a component for mineral resources systems

Quental, Lídia Maria; Oliveira, Daniel P. S.; Filipe, Augusto; Lopes, Catarina; Fortes, Carla
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em /05/2015 Português

‣ A multi-analytical approach to gold in Ancient Egypt: studies on provenance and corrosion

Tissot, I.; Troalen, L. G.; Manso, M.; Ponting, M.; Radtke, U.; Barreiros, Maria Alexandra; Shaw, I.; Carvalho, M. L.; Guerra, M. F.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2015 Português
Recent results from a three-year multi-disciplinary project on Ancient Egyptian gold jewellery revealed that items of jewellery from the Middle Kingdom to the New Kingdom were manufactured using a variety of alluvial gold alloys. These alloys cover a wide range of colours and the majority contain Platinum Group Elements inclusions. However, in all the gold foils analysed, these inclusions were found to be absent. In this work a selection of gilded wood and leather items and gold foil fragments, all from the excavations by John Garstang at Abydos (primarily from Middle Kingdom graves), were examined using Scanning Electron Microscopy-Energy Disperse Spectroscopy (SEM-EDS), X-Ray Fluorescence (µXRF), Particle Induced X-Ray Emission (µPIXE) and Double Dispersive X-Ray Fluorescence (D2XRF). The work allowed us to characterise the composition of the base-alloys and also to reveal the presence of Pt at trace levels, confirming the use of alluvial gold deposits. Corrosion products were also investigated in the foils where surface tarnish was visually observed. Results showed that the differences in the colour of corrosion observed for the foils are related not only to the thickness of the corrosion layer but also to a multi-layer structure containing the various corrosion products.

‣ Nitriding VI-group metals (Cr, Mo and W) in stream of NH3 gas under concentrated solar irradiation in a solar furnace at PSA (Plataforma Solar de Almería)

Oliveira, F. A. Costa; Rosa, Luís Guerra; Fernandes, Jorge Cruz; Rodriguez, José; Canadas, Inmaculada; Magalhães, Teresa; Shohoji, Nobumitsu
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2015 Português
Carbides and nitrides of d-group transition metals are classified as refractory hard material and their industrial importance has been recognized for long. In recent years, unique functionalities including catalytic function and superconductivity are discovered for this group of materials to raise serious attention of materials researchers and engineers to refractory carbides and nitrides as novel functional materials. Synthesis of refractory carbides and nitrides demands high temperature reaction route to consume considerable amount of electricity or gas in conventional industrial process. In view of saving cost of such conventional energy, feasibility of using concentrated solar beam as heat source for synthesizing carbide and nitride has been investigated by the authors since 1997. After verifying usefulness of concentrated solar beam as heat source for carbide forming reactions, similar attempts of employing concentrated solar beam as heat source for nitride synthesis were initiated recently. After brief experimental verification of nitride synthesis for IVa group metal, Ti, and Vg group metals, V, Nb and Ta, in N2 gas environment under irradiation with concentrated solar beam to 2000 °C, the authors decided to undertake nitride synthesis of VIa group metals...

‣ Low-temperature nitriding of VA-group metal powders (V,Nb,Ta) in flowing NH3 gas under heating with concentrated solar beam at PSA

Fernandes, Jorge Cruz; Oliveira, F. A. Costa; Rosa, Rosa, Luís Guerra; Rodríguez, José; Canadas, Inmaculada; Magalhães, Teresa; Shohoji, Nobumitsu
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em //2015 Português
Over the last two decades, we have been using concentrated solar beam as the reaction heat source for synthesizing carbides and nitrides of d-group transition elements in view of usage of ecological renewable energy source in place of conventional heat sources using electricity or gas. In recent works [1,2] nitriding of VIa-group metals (Cr, Mo, W) and Fe in stream of NH3 gas with suppressed extent of dissociation (uncracked NH3) was attempted under heating with concentrated solar beam. It was demonstrated that mono-nitride -MoN of Mo and sub-nitride -Fe2N of Fe that are known to be impossible to synthesize in N2 gas environment even at elevated pressure p(N2) were successfully synthesized by the reactions of these metals in stream of NH3 gas under heating with concentrated solar beam up to 800ºC. In the present work, nitriding of Va-group metals (V, Nb and Ta) was attempted in stream of NH3 gas under irradiation of concentrated solar beam. By up to 90 min heating in uncracked NH3 under concentrated solar beam up to 800ºC, reaction products were identified by X-ray diffraction (XRD) analysis to be consisted of mono-nitride MN co-existent with sub-nitride M2N.

‣ Reverse osmosis powered by concentrating solar power (CSP): a case study for Trapani, Sicily

Ahmed, Mahran K. A.; Cardoso, João P.; Mendes, J. Farinha; Casimiro, Sergio
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em //2015 Português
The objective of this paper is to analyse the physical performance of two technologies in a water and electricity co-generation scheme: Concentrated Solar Power (CSP) plant coupled to a Reverse Osmosis (RO) unit for a location in the city of Trapani, in southern Italy. The modelled system is compared with the results of another study [2], in which a Multi-Effect Desalination (MED) is powered by a CSP plant for the same location in Italy, using as reference an existing stand-alone gas powered MED plant located at Trapani [3] (which has operated until very recently). The overall aim is to assess and compare these two cogeneration schemes, using as reference the existing MED plant. This work was conducted using as the main simulation tool: the System Advisor Model (SAM) developed by the US National Renewable Energy Laboratory (NREL); a recent upgrade to SAM made available to this work through Laboratório Nacional de Energia e Geologia I.P. (LNEG); and the Reverse Osmosis System Analysis (ROSA) developed by the Dow Chemical Company. A technical visit to a real commercial RO plant in the south of Portugal (Alvor) was conducted, and the data gathered was used in the validation of the ROSA model. The results for the Trapani case study show that the CSP-RO arrangement has the capability to produce ~50% of the total production of the full scale plant at Trapani...

‣ ELV recycling steps up a gear: development of improved sorting technologies for the non-ferrous fraction of auto-shredders

Nogueira, C. A.; Pedrosa, Fátima; Margarido, F.; Santos, R. Novais; Durão, F.; Guimarães, C.
Fonte: PennWell Corporation Publicador: PennWell Corporation
Tipo: Artigo de Revista Científica
Publicado em //2015 Português
Although the number of end of life vehicles (ELVs) needing recycling is growing, due to processing limitations aluminium recycling rates are being hindered. A European-funded project - ShredderSort - aims to contribute to new solutions to the aluminium recycling industry. More than 10 million tons of automotive waste from end of life vehicles (ELV) are generated yearly in the EU and the values are continuously increasing. ELV wastes are managed by the auto-shredder plants which process ELVs through a series of mechanical and physical operations in order to separate the materials into different streams: ferrous, non-ferrous, heavy non-metal and fluff. Ferrous materials, constituting more than 60wt% (percentage by weight), are sent to steel-making plants, while the non-ferrous (NF) fraction, rich in aluminium and representing slightly less than 10wt%, is processed to separate some alloys.

‣ Minero-metallurgical processes for lithium recovery from pegmatitic ores = Processos minero-metalúrgicos para a recuperação de lítio de minérios pegmatíticos

Margarido, F.; Vieceli, N.; Durão, F.; Guimarães, C.; Nogueira, C. A.
Fonte: LNEG – Laboratório Nacional de Energia e Geologia, I.P. Publicador: LNEG – Laboratório Nacional de Energia e Geologia, I.P.
Tipo: Artigo de Revista Científica
Publicado em //2014 Português
ABSTRACT: With the expected increase of lithium demand in the forthcoming years, an efficient management of all the available resources is necessary. Rock minerals like pegmatites are important primary sources of lithium that shall be valorized. Minero-metallurgical processes have been developed for lithium recovery from pegmatitic ore deposits, involving physical concentration, thermal treatment, digestion and/or leaching in order to obtain a lithium soluble species adequate to produce lithium carbonate by precipitation. Physical concentration by froth flotation or by optical sorting are the two main alternative operations to produce a Li concentrate. Metallurgical treatment starts by calcination where the silicate structure is transformed to a more reactive solid phase (ß-spodumene). Afterwards digestion with sulfuric acid and water leaching allows the dissolution of lithium sulfate. Carbonate pressure leaching is an alternative technology for treating pegmatites and production of lithium carbonate. Energy and chemicals savings is crucial in order to reduce the high costs associated with metallurgical processing of Li rock minerals.  ; RESUMO: Com o aumento na procura de lítio nos próximos anos, torna-se necessária uma gestão eficiente de todos os recursos disponíveis. Os minérios pegmatíticos são fontes primárias importantes deste metal que devem ser valorizadas. Neste contexto...