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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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Toxicity of Ashes Produced During the Combustion and Co-combustion of Coal and Meat and Bone Meal in a Fluidized- Bed Reactor

Barbosa, Rui; Lapa, N.; Lopes, M. Helena; Gulyurtlu, Ibrahim; Mendes, Benilde
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em /10/2009 Português
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The replacement of fossil fuels by renewable fuels can contribute to improve the environmental performance of the power production and to move forward in the sustainability way. The experience has shown that the availability of alternative fuels can be an obstacle for its extensive use for energy production, since biomass is not always available. The use of non-hazardous wastes may be a good alternative to biomass, mainly if they are economically unattractive for recycling or if they present a high cost for land-filling. The co-firing of non-hazardous wastes with coal is, therefore, a subject of great interest for the sustainability of energy production and the reduction of the emissions of fossil greenhouse gases. The use of these wastes for energy is promising if they combine well with other fuels during the conversion process for energy production and have no negative effect on the combustion system, on the ash quality and on the gaseous emissions.

TGGE-monitoring of the microbial community along the olive mill wastewaters anaerobic treatment

Eusébio, Ana; Tacão, M.; Baeta-Hall, Lina; Freitas, P.; Almeida-Vara, Elsa; Marques, Isabel Paula Ramos
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em 06/04/2008 Português
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Geochemistry of minerals, waters and weathering from the Fonte Santa mine area, NE of Portugal

Gomes, M. E. P.; Antunes, I. Margarida H. Ribeiro; Neiva, Ana Margarida R.; Pacheco, F. A. L.; Silva, Paulo Bravo
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em /09/2009 Português
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The quartz veins containing scheelite from Fonte Santa mine area were exploited for W between 1942 and 1982. At the end of November 2006, a flood event damaged the dam land of Fonte Santa mine and metal content of water increased. Fonte Santa mine area cuts the quartzites close to the Fonte Santa muscovite granite. The granite contains quartz, microcline, albite, muscovite, chlorite, columbite-tantalite, volframite, W-ixiolite and ilmenite. The quartz veins contain muscovite, chlorite, tourmaline, scheelite, pyrrhotite, pyrite, sphalerite, chalcopyrite, galena, arsenopyrite, magnetite, jarosite, phosphates of Pb, Fe and AI. The waters related to the Fonte Santa mine are poorly mineralized, with electrical conductivity < 965 ~S / cm, of mixed type or HCO3- and SO42- types. These waters have Fe and Mn contents that forbid to use that for human consumption and agriculture. Sodium, Mg and K water contents are associated with the alteration of albite, chlorite and muscovite of country rock, while Ca is related to the W-bearing quartz veins.

Transient inversion during the opening stage of the Wilson cycle, Sardic phase, in the Iberian Variscides : stratigraphic and tectonic records

Romão, José Manuel; Coke, Carlos; Dias, Ruben P.; Ribeiro, António
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em /06/2003 Português
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Geomorfologia do Parque Natural de Montesinho : controlo estrutural e superfícies de aplanamento

Pereira, P.; Pereira, Diamantino Ínsua; Alves, Maria Isabel C.; Meireles, Carlos
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em /06/2003 Português
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Cartografia temática do georrecurso, Brecha Algarvia

Henriques, Paulo; Machado, Susana; Quartau, Rui; Carvalho, Jorge M. F.; Manuppella, Giuseppe
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em /06/2003 Português
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Avaliação por modelação em SIG da contaminação mineira por drenagem ácida em S. Domingos, Faixa Piritosa, Alentejo

Batista, Maria João; Brito, M. G.; Abreu, Maria Manuela; Sousa, A. J.; Quental, Lídia Maria; Vairinho, M. Margarida
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em /06/2003 Português
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Pesquisa de Benzo[a]pireno em produtos cárneos fumados caseiros e industriais da zona de Abrantes – Portuga

Costa, Maria do Céu; Silveira, Catarina; Rovisco, Eduardo; Gomes, Ana; Pereira, Paulo; Roseiro, L. Cristina; Santos, Carlos Nunes dos
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em 28/10/2010 Português
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Polarity reversal by fuel starvation in PEM Fuel Cells

Travassos, Maria Antónia; Rangel, C. M.
Tipo: Artigo de Revista Científica
Publicado em //2011 Português
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In this work, the degradation caused by polarity reversal by fuel starvation of a 16 MEA (membrane-electrode assembly) – low power PEM fuel cell is reported. Measuring of the potential of individual cells, while on load, was found instrumental in the location of affected cells which revealed very low or even negative potential. Ex-situ analysis of MEA, after irreversible degradation by fuel starvation, gave as a result delamination of catalyst layers with impacts on fuel cell performance such as development of flooded areas (in the created gaps by membrane separation) increasing the resistance of reactant transport to the catalyst sites. Striking thickness variations of the anode layers as well as carbon corrosion were found. Also, the proton exchange membrane was found to be affected by fluoride depletion.

Environmental effects on glazed ceramics : green stains in 18th century blue-and-white portuguese tile glazes

Silva, Teresa Pereira; Figueiredo, M. Ondina; Barreiros, A.; Prudêncio, Maria Isabel
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em /05/2012 Português
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Cartografia geológica da Guiné-Bissau

Alves, Paulo Hagendorn
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em /01/2012 Português
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North Atlantic paleo-productivity changes during Marine Isotope Stages (MIS) 10 to 16 - Coccolithophore Sr-Ca evidence

Cavaleiro, C.; Voelker, Antje H. L.; Stoll, H.; Kulhanek, D. K.
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em /12/2012 Português
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Assessment of the sustainable offshore wind potential in Portugal

Costa, P.; Simões, T.; Estanqueiro, Ana
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em //2006 Português
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The sustainable offshore wind potential for the west and south coasts of Portugal is presented. Results were carried out using an atmospheric mesoscale model and GIS tools. Unlike previous common opinions, the preliminary results show the existence of interesting areas for the developing of offshore wind parks.

Water management in a passive direct methanol fuel cell

Oliveira, V. B.; Falcão, D. S.; Rangel, C. M.; Pinto, A. M. F. R.
Fonte: John Wiley & Sons Publicador: John Wiley & Sons
Tipo: Artigo de Revista Científica
Publicado em //2013 Português
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Passive direct methanol fuel cells (DMFCs) are under development for use in portable applications because of their enhanced energy density in comparison with other fuel cell types. The most significant obstacles for DMFC development are methanol and water crossover because methanol diffuses through the membrane generating heat but no power. The presence of a large amount of water floods the cathode and reduces cell performance. The present study was carried out to understand the performance of passive DMFCs, focused on the water crossover through the membrane from the anode to the cathode side. The water crossover behaviour in passive DMFCs was studied analytically with the results of a developed model for passive DMFCs. The model was validated with an in-house designed passive DMFC. The effect of methanol concentration, membrane thickness, gas diffusion layer material and thickness and catalyst loading on fuel cell performance and water crossover is presented. Water crossover was lowered with reduction on methanol concentration, reduction of membrane thickness and increase on anode diffusion layer thickness and anode and cathode catalyst layer thickness. It was found that these conditions also reduced methanol crossover rate. A membrane electrode assembly was proposed to achieve low methanol and water crossover and high power density...

GeoPortal do LNEG - uma ferramenta para disponibilização de cartografia geológica oficial

Almeida, Paula Alexandra C.; Patinha, Pedro; Luís, Gabriel
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em /12/2013 Português
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Pre-treatment of lignocellulosic biomass using ionic liquids: wheat straw fractionation

Lopes, André; João, Karen; Rubik, Djonatam; Bogel-Lukasik, Ewa; Duarte, Luís C.; Andreaus, Jurgen; Bogel-Lukasik, R.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2013 Português
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This work is devoted to study pre-treatment methodologies of wheat straw with 1-ethyl-3-methylimidazolium acetate ([emim][CH3COO]) and subsequent fractionation to cellulose, hemicellulose and lignin. The method developed and described here allows the separation into high purity carbohydrate and lignin fractions and permits an efficient IL recovery. A versatility of the established method was confirmed by the IL reuse. The fractionation of completely dissolved biomass led to cellulose-rich and hemicellulose-rich fractions. A high purity lignin was also achieved. To verify the potential further applicability of the obtained carbohydrate-rich fractions, and to evaluate the pre-treatment efficiency, the cellulose fraction resulting from the treatment with [emim][CH3COO] was subjected to enzymatic hydrolysis. Results showed a very high digestibility of the cellulose samples and confirmed a high glucose yield for the optimized pre-treatment methodology.

LNEG 2.0: Mais inovação e competitividade: Inovação organizacional e alinhamento estratégico

Leão, Teresa Ponce de; Costa, Maria do Céu
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em //2014 Português
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Matérias primas críticas para a Europa : o caso do rénio

Figueiredo, M. Ondina
Tipo: info:eu-repo/semantics/lecture
Publicado em /03/2014 Português
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Resumo de palestra inserida no Ciclo de Palestras 2014 do LNEG

The Levelized Cost of Energy (LCOE) of wave energy using GIS based analysis: the case study of Portugal

Castro-Santos, Laura; Garcia, Geuffer; Estanqueiro, Ana; Justino, Paulo Alexandre
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2015 Português
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The main objective of this paper is to establish an economic modelling of wave energy through a Geographical Information System (GIS). Furthermore, this method has been tested for the particular case of the Portuguese coast. It determines the best sea areas to install wave energy converters in this region, using spatial analysis of the Levelized Cost of Energy (LCOE). Several economic parameters, as capital or O&M costs, have been considered. In addition, a sensitivity analysis has been performed by varying the discount rate in three different scenarios. Several types of physical restrictions have been taken into account: bathymetry, submarine electrical cables, seabed geology, environmental conditions, protected areas in terms of heritage, navigation areas, seismic fault lines, etc. Spatial operations have been carried out to complete the procedure, using Model Builder of GIS software. Results indicate the most suitable areas in economic terms in Portugal to install wave energy devices.

C-O-H isotopic evidences for fluid sources of granulites in Ribeira Belt, SE Brazil

Bento dos Santos, Telmo; Munhá, José; Tassinari, Colombo C. G.; Fonseca, Paulo E.
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em /07/2008 Português
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Publicado em: Geochemica et Cosmochimica Acta, Vol. 72, issue 12, Suppl. 1, A75