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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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Contributos para a protecção dos recursos hídricos subterrâneos numa área agrícola com características semi-áridas em Portugal

Leitão, Teresa E.; Laranjeira, Isabel; Paralta, Eduardo; Cunha, Maria da Conceição
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em //2007 Português
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Neste artigo apresenta-se uma breve síntese do projecto "Metodologias para um melhor planeamento e gestão do uso do solo agrícola atendendo à vulnerabilidade dos aquíferos à poluição difusa", em curso em Portugal entre Maio de 2005/2008, coordenado pelo Laboratório Nacional de Engenharia Civil, com a participação do Instituto de Ciências Agrárias e Mediterrânicas, do Instituto do Mar e do Instituto Superior Técnico. O objecto deste projecto enquadra-se nos propósitos mais vastos da Directiva-Quadro da Água (DQA) e da Directiva das Águas Subterrâneas, de alcançar o Bom estado das águas subterrâneas (definido na DQA) até 2015, através de um conjunto de actuações destinadas à protecção das massas de água e à redução gradual da poluição em massas de água já poluídas. Estes objectivos só serão alcançados através de medidas de gestão integrada e sustentável dos recursos hídricos ao nível da bacia hidrográfica, onde as opções de uso e ocupação do solo tenham em consideração se os seus efeitos são compatíveis com os padrões de qualidade impostos para as características das águas subterrâneas de jusante. Nesse contexto, o objectivo global do projecto é estimular a utilização futura de culturas associadas a práticas agrícolas mais sustentáveis que possam contribuir para diminuir o risco de degradação da qualidade das águas subterrâneas atendendo...

Recommendation on Summer energy efficiency on national building codes

Gonçalves, Helder; Camelo, Susana
Fonte: LNEG Publicador: LNEG
Tipo: info:eu-repo/semantics/book
Publicado em //2009 Português
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The building regulations have a major role in controlling and limiting the energy consumption of the building sector. The Thermal Building Regulations of the European countries although had followed the EPBD Directive in what concerns the methodologies, differs on the re-quirements and recommendations on summer comfort and energy consumption for cooling, due to the particular conditions of each country. A review of the national building codes concerning envelope constructive solutions (opaque and transparent), thermal mass, ventilation rates, energy consumption methodology and correspondent values limits has been undertaken for the participating countries of the Keep-Cool II Project and, was extended to other countries, by consulting building codes, technical reports concerning energy use in buildings and by direct contacts with colleagues. The goal of this analysis consists on put in evidence the different strategies adopted and try to share and to supply information and experiences in so far as, the energy demand for cooling in European buildings is the energy use in the building sector with high increase rate among the other energy uses. In fact, cooling can be avoided or significantly reduced, with-out risking summer thermal comfort...

Yeast metabolic state identification by fiber optics spectroscopy

Castro, C. C.; Silva, J. S.; Lopes, Vitor V.; Martins, R. C.
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em //2009 Português
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In this manuscript we explore the feasibility of using LWUV-VIS-SWNIR (340 - 1100 nm) spectroscopy to classify Saccharomyces cerevisiae colony structures in YP agar and YPD agar, under different growth conditions, such as: i) no alcohol; ii) 1 % (v/v) Ethanol; iii) 1 % (v/v) 1-Propanol; iv) 1 % (v/v) 1- butanol; v) 1 % (v/v) Isopropanol; vi) 1 % (v/v) (±)-1-Phenylethanol; vii) 1 % (v/v) Isoamyl alcohol; viii) 1 % (v/v) tert-Amyl alcohol (2-Methyl-2-butanol); and ix) 1 % (v/v) Amyl alcohol. Results show that LWUV-VISSWNIR spectroscopy has the potential for yeasts metabolic state identification once the spectral signatures of colonies differs from each others, being possible to acheive 100% of classification in UV-VIS and VISSWNIR. The UV-VIS region present high discriminant information (350-450 nm), and different responses to UV excitation were obtained. Therefore, high precision is obtained because UV-VIS and VIS-NIR exhibit different kinds of information. In the future, high precision analytical chemistry techniques such as mass spectroscopy and molecular biology transcriptomic studies should be performed in order to understand the detailed cell metabolism and genomic phenomena that characterize the yeast colony state

Silurian of the Barrancos-Hinojales domain of SW Iberia : a contribution to the geological heritage of the Barrancos area, Portugal, and the Sierra de Aracena-Picos de Aroche Natural Park, Spain

Piçarra, José Manuel; Gutiérrez-Marco, Juan Carlos; Sarmiento, Graciela Noemi; Rábano, Isabel
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em /06/2009 Português
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Sondagem de Belverde, Bacia do Baixo Tejo, Península de Setúbal, Portugal

Pais, João; Lopes, Carlos Silva; Legoinha, Paulo; Ramalho, Elsa Cristina; Ferreira, João; Ribeiro, Isabel; Amado, Ana Rita; Sousa, Lígia; Torres, Luís; Baptista, Rui; Reis, Rui Pena
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em /06/2003 Português
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Estudo de lineamentos fotointerpretados na região do Algarve ocidental

Moniz, Catarina; González-Clavijo, Emilio J.; Matias, L.; Cabral, João
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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Os recursos minerais e o acesso ao território : conclusões dos workshops regionais

Santana, Helena; Martins, Luís Plácido
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em /02/2010 Português
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PEM Fuel Cells: materials ageing and degradation

Silva, R. A.; Paiva, T. I.; Rangel, C. M.
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em 29/04/2010 Português
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As fuel cell technology matures and time scale to commercialization decreases, the need for a more comprehensive knowledge of materials ageing mechanisms is essential to attain specified lifetime requirements for applications. In this work, the membrane-electrode assembly (MEA) degradation of an eight cell PEM low power stack was evaluated, during and after fuel cell ageing in extreme testing conditions. The stack degradation analysis comprised observation of catalytic layer, morphology and composition. Cross sections examination of the MEAs revealed thickness variation of catalytic layer and membrane. Other modes of degradation such as cracking,

Sedimentos marinhos : caracterização química expedita por espectrometria de fluorescência de raios X = Marine sediments : an easy-and-quick chemical characterization through X-ray fluorescence spectrometry

Figueiredo, M. Ondina; Nave, Sílvia; Silva, Teresa Pereira
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em /07/2010 Português
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Com o objectivo de obter dados químicos sobre sedimentos marinhos em tempo reduzido e por uma via expedita, desenvolveu-se uma metodologia analítica baseada em espectrometria de fluorescência de raios X por dispersão em comprimentos de onfa (FRX-DCO). Descreve-se esta metodologia expedita não destrutiva e apresentam-se os primeiros resultados relativos a uma secção de uma sondagem de sedimentos marinhos, testados com sucesso por comparação com dados obtidos por uma técnica analítica de aplicação corrente.

Graptólitos do Silúrico do Sinclinal de Buçaco : paleontologia e biostratigrafia = Graptolite faunas from Silurian of the Buçaco Syncline : paleontology and biostratigraphy

Piçarra, José Manuel; Sequeira, António J. D.
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em /07/2010 Português
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Estudaram-se exemplares de Graptólitos do Silúrico do sinclinal de Buçaco proveninentes de colecções de Nery Delgado e de amostragem recente. Foi realizada a actualização taxonómica das colecções antigas. Determinaram-se novas espécies e biozonas. Os novos resultados permitem precisar o Silúrico do Buçaco que tem muitas características estratigráficas e sedimentológicas em comum com o de outras áreas da parte sul da Zona Centro Ibérica.

Identificação de estruturas com potencial sismogénico na Região do Vale Inferior do Tejo = Identification of Seismogenic Structures in the Lower Tagus Basin

Pinto, Carlos C.
Tipo: info:eu-repo/semantics/masterthesis
Publicado em /11/2011 Português
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Quartzo de pegmatitos graníticos : uma matéria-prima para alta tecnologia

Figueiredo, M. Ondina
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em //2011 Português
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Soda and aluminum recovery from spent etching baths by aqueous precipitation

Berto, Andrea; Nogueira, C. A.; Margarido, F.
Fonte: Trans Tech Publications Publicador: Trans Tech Publications
Tipo: Artigo de Revista Científica
Publicado em //2013 Português
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The aluminum anodising industry is an important industrial sector that produces great amounts of polluted effluents, which after treatment generate sludge. This fact brings environmental and economical concerns to the companies. Best way to deal with the problem, according to the “prevention strategy” set by the European Directive on Integrated Pollution Prevention and Control, is to implement preventive techniques and technologies to optimise the use of resources and minimise losses, and in turn waste. Among the operations of an anodising line, the etching/satinising stage is responsible for the production of a huge quantity of wastewater neutralisation sludge and for the wrong use of caustic soda. “Caustic etch recovery” technology is claimed to drastically reduce the generation of neutralisation sludge and the purchasing of fresh caustic soda by regenerating the exhausted etching/satinising solution, through an aqueous precipitation reaction. This paper presents the capability of the technology to effectively regenerate the exhausted caustic solution, and investigated the parameters with major effect on the process yield, in order to optimise it. It was demonstrated that the technology effectively recovers the solution, increases its soda content and diminishes the dissolved aluminum content by precipitation. Moreover the conditions that optimise the process are simple and inexpensive. After treatment the solution present the properties to be recycled in the etching/satinising operation.

Contribution to EPMA to airbone pollen analysis

Guimarães, Fernanda M. G.; Duque, L.; Ribeiro, H.; Sousa, R.; Abreu, I.
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em /05/2011 Português
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As a component of aerosol, pollen is found in suspension with other mineralogical and anthropogenic particles that can adhere to the pollen wall. The aim of this study was to determine possible alterations that pollen grains suffer under different meteorological conditions in the coastal city of Porto, Portugal. For this study, 2 airborne pollen types were taken into account: Poaceae and Alnus spp sampled in July 2010 and February 2011, respectively. Quantitative analysis and X-ray map analysis were performed with a Field Emission Electron Probe Microanalyser (EPMA). Samples were mounted over adhesive carbon tape and carbon coated. Control pollen showed mainly the presence of C, O, N, P, K, Mg, S, Cl and Ca in different quantities, depending on the considered species. Airborne pollen consistently revealed a higher content of Mg and Cl than control pollen, while Si, Ca, K and P contents varied differently according to the samples. Our results show that during their “flight”, pollen grains acquire an external coating, become heavier and change significantly their composition.

Cork boiling wastewater 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 boiling wastewater (CBW) is a very important effluent of the cork processing industry which is produced in the western Mediterranean region and western north of Africa. CBW has no utility till now constituting an environmental hazard. It is a complex liquid stream which is produced during the boiling of the cork planks. This process step is one of the key operations in cork processing. CBW is known as having suspended and dissolved solids and organic materials such as phenolic compounds being characterized by a low biodegradability and an acid pH.

CHRONIBERIA : ongoing development of a geochronological GIS database of Iberia

Lopes, C.; Ferreira, A.; Chichorro, Martím A.; Pereira, Manuel Francisco Costa; Almeida, J. A.; Solá, Ana Rita
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em /07/2013 Português
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Energy performance certificate: a valuable tool for building-to-grid interaction?

Panão, Marta Oliveira; Gonçalves, Helder
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em //2013 Português
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New challenges were opened with the recast of Energy Performance of Buildings Directive, requiring by 2020 that new buildings be “nearly Zero-Energy Buildings” (nearly ZEB). In addition to consumer buildings, Net ZEBs are also producers’ by using as much renewable energy sources as possible to compensate the building energy load. Sustainable cities require energy-efficient buildings, i.e. buildings where the use of energy is minimized without compromising the occupants comfort, namely for heating, cooling, lighting and indoor air quality. But smart cities require energy-efficient ‘interactive’ buildings, which integrate multiplecarrier energy networks and provide up-to-date valuable information for their management, where buildings are simplified to single nodes characterized by their energy load, generation, storage and conversion, applying the load-generation approach. The information currently available in the Energy Performance Certificate is not relevant for estimating the time dependent building energy load, but it can be easily improved by including a few descriptive parameters.

Optimality-based bound contraction with multiparametric disaggregation for the global optimization of mixed-integer bilinear problems

Castro, Pedro; Grossmann, Ignacio E.
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
Publicado em //2014 Português
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We address nonconvex mixed-integer bilinear problems where the main challenge is the computation of a tight upper bound for the objective function to be maximized. This can be obtained by using the recently developed concept of multiparametric disaggregation following the solution of a mixed-integer linear relaxation of the bilinear problem. Besides showing that it can provide tighter bounds than a commercial global optimization solver within a given computational time, we propose to also take advantage of the relaxed formulation for contracting the variables domain and further reduce the optimality gap. Through the solution of a real-life case study from a hydroelectric power system, we show that this can be an efficient approach depending on the problem size. The relaxed formulation from multiparametric formulation is provided for a generic numeric representation system featuring a base between 2 (binary) and 10 (decimal).

Evidence of intraplate deformation in the West Madeira Abyssal Plain (eastern North Atlantic) from seismic reflection and multibeam swalth bathymetry data

Roque, Ana Cristina; Simões, M.; Lourenço, Nuno; Abreu, M. Pinto de
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em /04/2009 Português
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