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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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Assessing and modelling hard rock aquifer recharge based on complementary methodologies : a case study in the Gabbros of Beja Aquifer System, South Portugal

Paralta, Eduardo; Oliveira, M.
Tipo: info:eu-repo/semantics/other
Publicado em /05/2005 Português
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The "Gabbros of Beja" Aquifer System extends for approximately 350 km2 and is one of the most important reservoirs of groundwater in the context of hard rocks aquifers of South Portugal (Alentejo Region). The average annual rainfall in the area is about 500 to 600 mm. Groundwater resources are used for public supply over 3 councils and irrigation. During drought cycles consumption increases and pumping rates decrease with correspondent management difficulties and conflicts between private and public interests. The correct assessment of annual recharge is of utmost importance for regional planning and management of groundwater resources under semiarid climate conditions. Moreover the aquifer was recently declared vulnerable to nitrate diffuse pollution of agriculture origin and recharge mechanisms are the major natural factor controlling contamination of shallow waters in the "Gabbros of Beja" aquifer. Recharge assessment and modelling was performed on the base of several complementary methodologies: 1) water balance based on historical data of annual pumping rates; 2) chloride mass balance between groundwater and rainfall compositions; 3) daily sequential water balance modelling of hydrological parameters using Balseq model, and 4) soil and vadose zone daily water balance modelling using lumped model Earth and piezometric water level curves for calibration. Results of direct and indirect methods show that annual average recharge should be between 10% and 20% or even more of annual rainfall.

Electrodeposition of black chromium from CR(III) ionic liquid solution

Eugénio, S.; Rangel, C. M.; Vilar, Rui
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em 21/09/2009 Português
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Black chromium is an important coating material used in solar thermal systems as a spectrally selective surface. This coating is usually obtained by electrodeposition from sulphate free chromium (VI) aqueous solutions which represent a health and environmental hazard due to the presence of Cr(VI), a known toxic and carcinogenic agent. Recent developments in green chemistry have shown that ionic liquids can be used as electrolytes, allowing the deposition of a wide range of materials with negligible environmental and health impacts. In the present study, the electrodeposition of black chromium films from a solution of ionic liquid containing chromium (III) has been investigated by cyclic voltammetry and chronoamperometry. Homogeneous and well adherent black Cr films have been obtained on several substrates, by potentiostatic electrodeposition. The films morphology and composition have been characterised by SEM/EDS and GI-XRD.

Hidrogeologia

Pereira, Ana Paula
Tipo: Artigo de Revista Científica
Publicado em //2008 Português
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O novo RCCTE: Estratégias e medidas para a sua verificação

Gonçalves, Helder; Horta, Cristina; Ramalho, Álvaro; Camelo, Susana; Graça, João Mariz
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em /11/2006 Português
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Post-metamorphic evolution of the Lower Cambrian section at Enfermarias, Moura, Portugal : its record and metallogenic implications

Martins, R.; Mateus, António; Figueiras, Jorge; Barroso, M.; Oliveira, V.
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em /06/2003 Português
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A Formação de Vale do Guizo e o bordo oriental da Bacia do Baixo Tejo entre Crato e Avis : dados preliminares

Costa, A. M.; Pimentel, N. L. V.; Barbosa, Bernardo
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em /06/2003 Português
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Cartografia temática e breve caracterização dos depósitos argilosos nos terraços fluviais de Aileu, Timor Leste

Lisboa, J. Vítor; Carvalho, Jorge M. F.; Oliveira, Álvaro; Carvalho, C.; Grade, José
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em /06/2003 Português
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Efectuou-se a cartografia litoestrutural dos depósitos argilosos nos terraços fluviais de Aileu (Timor Leste) e respectiva amostragem, com vista a uma primeira caracterização e avaliação das potencialidades daqueles depósitos. Estes constituem níveis de areia fina, silte e argila, de cor branca amarelada ou acizentada. As argilas amostradas são ilito-quartzo-cauliníticas com interestratificados de ilite-vermiculite em teores acessórios, ocorrendo também feldspato potássico. Os níveis argilosos têm estrutura tabular, estão confinados e nos locais onde não afloram, têm uma cobertura pouco espessa de terraço, com possibilidade de desmonte. Considerando algumas condicionantes, (espessura, a superfície ocupada pelos depósitos e perdas de rendimento), admite-se um volume para os recursos da ordem dos dois milhões de metros cúbicos. Estas argilas têm aptidão no sector da cerâmica do barro branco.

Comparison of a pilot scale gasification installation performance when air or oxygen is used as gasificatio medium

Pinto, Filomena; Gulyurtlu, Ibrahim; André, Rui Neto; Lopes, M. Helena; Franco, Carlos
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em 06/09/2010 Português
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Petrological cooling rates from central Ribeira Belt, SE Brazil : new breakthroughs and developments [Abstract]

Bento dos Santos, Telmo; Munhá, José; Fonseca, Paulo E.; Tassinari, Colombo C. G.
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em /06/2010 Português
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Seismotectonics of the Gulf of Cadiz: new insights from instrumental seismicity

Silva, S. M.; Romsdorf, M.; Matias, L.; Terrinha, Pedro; Geissier, W.
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em /10/2010 Português
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Evolução e estrutura da zona de cisalhamento dúctil Malpica-Lamego : livro guia da excursão pós-congresso

Castro, Paulo Ferreira; Coke, Carlos; Ferreira, Narciso; Llana-Fúnez, S.; Pamplona, J.; Pereira, Eurico; Pimenta, P.; Rodrigues, B. C.; Rodrigues, José Feliciano
Tipo: info:eu-repo/semantics/book
Publicado em //2010 Português
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Effect of the oxide loading on the surface characteristics of LaNio3 oxide coated electrodes

Soares, C. O.; Silva, R. A.; Carvalho, M. D.; Jorge, M. E. Melo; Gomes, A.; Rangel, C. M.; Pereira, M. I. da Silva
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em 12/12/2011 Português
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The LaNiO3 perovskite-type oxide is one of the most tested anode for the oxygen evolution reaction in alkaline solutions. It is well established that the oxide preparation conditions and the electrode fabrication are key factors to control the electrochemical behaviour of oxide coatings. In a previous work the authors studied the influence of preparation conditions of the oxide and support type on the electrochemical behaviour of Ni foam coated LaNiO3 electrodes. Ni foam was selected as support due to its unique characteristics namely low contact resistance between the oxide and support, possibility of high metal oxide loadings and dimensional stability [1]. No studies were performed, concerning the influence of the oxide loading. Studies performed by Singh et al. on LaNiO3 coatings on Ni foil supports have shown that the electrode roughness factor increased with increase in oxide loading at the beginning and finally attained a constant value around 0.03 g cm-2 [2]. The present work reports on the study of the dependence of roughness factor (Rf) and morphology factor (φ) on the oxide loading for Ni foam coated LaNiO3 electrodes with loadings varying between 0.02 and 0.14 g cm-2. Cyclic voltammetry and electrochemical impedance spectroscopy were used to evaluate the Rf and φ values...

Padrões de fraturação regional e exploração de rochas ornamentais

Carvalho, Jorge M. F.; Lisboa, J. Vítor
Tipo: info:eu-repo/semantics/bookpart
Publicado em //2013 Português
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Publicação da Red Minería XXI. - Red Iberoamericana para la aplicación y divulgación de tecnologías limpias enfocadas a la caracterización y aprovechamiento de recursos minerales.

A Bacia Lusitaniana : estratigrafia, paleogeografia e tectónica

Kullberg, José Carlos; Rocha, Rogério Bordalo; Soares, A. F.; Rey, Jacques; Terrinha, Pedro; Azerêdo, Ana Cristina; Callapez, Pedro; Duarte, Luís Victor; Kullberg, Maria Carla; Martins, L.; Miranda, R. M.; Alves, Carlos; Mata, João; Madeira, J.; Mate
Tipo: info:eu-repo/semantics/bookpart
Publicado em //2013 Português
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Lousal, Portugal : património geológico e mineiro de uma antiga mina na Faixa Piritosa Ibérica

Oliveira, M.; Ferreira, T.; Relvas, Jorge M. R. S.; Pinto, A. M. M.; Pereira, Zélia; Matos, João Xavier; Fernandes, Carlos
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em /09/2013 Português
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Geologia da região costeira de Maputo-Catembe

Dias, Ruben P.; Oliveira, José Tomás
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em 14/05/2013 Português
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Estudos geológicos no sinclinal de Moncorvo

Ribeiro, Maria Luísa; Coutinho, Júlio; Barros, Rui de; Ribeiro, António
Tipo: Artigo de Revista Científica
Publicado em /03/1966 Português
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Cork wastes treatment and biogas production

Marques, Isabel Paula Ramos; Gil, Luís
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em //2013 Português
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Cork industry is an important economic and social sector in the western Mediterranean region. Portugal is the producer and processing leader of this sector. The cork processing industry gives rise to several effluents that must be treated and valorised. This work is a part of a study that aims to develop an integrated process in order to maximize the valorization of the different wastes/effluents of the cork processing sector taking in count the biorefinery concept. The main objective of the present work is to conduct a survey of all operations involve in the cork processing and identify the possible effluents which may be treated and valorise by anaerobic digestion for energy production.

Petrology and geochemistry of granulites from the São Fidelis area, Ribeira Belt, SE Brazil

Bento dos Santos, Telmo; Munhá, José; Tassinari, Colombo C. G.; Fonseca, Paulo E.; Neto, Coriolano Dias
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em /07/2007 Português
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Synthesis, optical and electrochemical properties of perylenes dyes for solar cells applications

Torres, Erica; Sequeira, S.; Berberan-Santos, M. N.; Brites, Maria João
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em //2014 Português
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Perylene monoimides or monoanhydrides are being intensively investigated as sensitizers in DSSCs. Keeping only one acceptor group, i.e. imide or anhydride, and introducing a donor group in the 9-position (such as diarylamine) proved to be important in order to obtain a favorable orbital partitioning strength and dipole moment of perylene compounds for DSSCs [1]. One way to control optical and electrochemical properties of perylenes dyes is achieved by functionalizing periand bay positions of perylene core with different substituents. In a simplified view, the peri groups coarsely tune the spectroscopic and electrochemical properties whereas the bay functional groups provide an additional fine tuning [2,3]. Here we report the design and synthesis of new perylene dyes (Figure 1) comprising: (1) a 4-alkoxyphenylamino moiety in the 9-position as a strong donating group, (2) a cyanoacrylic acid as electron acceptor and anchoring group and (3) a triple bond as short and rigid linker between perylene core and the acceptor group [4]. The photophysical properties (i.e. absorption and emission spectra, absorption extinction coefficients, fluorescence quantum yields and lifetime measurements) and electrochemical properties of the new perylene dyes were investigated and all results will be presented and discussed.