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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‣ Águas subterrâneas : recurso escondido e esquecido

Pereira, Ana Paula Teixeira; Santos, Renata; Pinto, Paulo
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em //2010 Português
Comunicação apresentada em Powerpoint, composta por 16 slides

‣ Linkages between North Atlantic surface water circulation patterns and Mediterranean outflow variability on the Western Iberian Margin : examples from marine isotope stages 3 and 12 to 10

Voelker, Antje H. L.; Lebreiro, Susana; Rodrigues, Teresa; Abrantes, Fátima; Martin, Pamela A.
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em /10/2007 Português

‣ Provenance analysis of the Late Ediacaran basins from Southwestern Iberia (Série Negra Succession and Beiras Group) : evidence for a common Neoproterozoic evolution

Chichorro, Martím A.; Solá, Ana Rita; Pereira, M. Francisco; Hofmann, Mandy; Linnemann, Ulf; Gerdes, Axel; Medina, J.; Lopes, L.; Silva, J. Brandão
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em //2014 Português

‣ Separation of non-ferrous frations of shredded end-of-life vehicles for valorising its alloys

Margarido, F.; Santos, R. Novais; Durão, F.; Guimarães, C.; Nogueira, C. A.; Oliveira, Paula C.; Pedrosa, Fátima; Gonçalves, Ana Maria
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em //2014 Português
Worldwide the end-of-life vehicles (ELV) generate millions of tons of waste, requiring an adequate and efficient management. The non-ferrous fraction contains essentially aluminium, magnesium and copper alloys, being valorised by metallurgical processors to obtain new metals and alloys. However most of the recovered metals are downcycled, as is the case of aluminium where the recycled products are essentially used to produce less purity casting alloys. New or improved separation technologies are therefore necessary in order to allow an accurate separation of alloys or alloy groups, increasing the value of the non-ferrous streams. In this paper, the composition of the non-ferrous fractions of ELV shredders are assessed with particular relevance for the aluminium and magnesium alloys. Essentially, the main cast and wrought alloys are characterized and their markets and applications are discussed. Based on waste composition, several physical separation and sorting technologies can be applied to improve the products quality, which are here depicted and discussed. Physical processing includes operations such as eddy current and heavy media separations. For sorting alloys contained in the non-ferrous stream, other sensor-based technologies are being developed...

‣ Comparison of processes for lithium recovery from lepidolite by H2SO4 digestion or HCl leaching

Nogueira, C. A.; Margarido, F.; Vieceli, N.; Durão, F.; Guimarães, C.
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em //2014 Português
Lithium is becoming a strategic metal due to its important applications in secondary battery electrodes used in electronic appliances and also in electric traction vehicles. Lithium primary resources are brines and rock minerals, the former being nowadays almost exclusively used in the production of lithium commodities. With the expected increase in lithium demand, the development of competitive technologies for recovery lithium from ores like pegmatites is getting imperative. The high energy and reagents consumption in processing minerals is an issue that should be considered. This paper presents some results on the comparison of two acid treatment routes for lepidolite, the H2SO4 digestion and HCl leaching. Before both chemical treatments, lepidolite was calcined at 800oC and was transformed in a more reactive species, ƒÀ-spodumene. The H2SO4 digestion at 175oC (followed by water leaching) allowed 88% Li recovery into the solution in 30 min. By the contrary, the HCl leaching process carried out at 90oC also achieved similar yields but only after 4 h of reaction. In both cases, an acid excess was used, but clearly higher for the essays with HCl. The H2SO4 digestion process was also advantageous in what concerns to selectivity over other contained metals. Al...

‣ Zygosaccharomyces bailii strain talf1 inulinases/invertases towards enhanced bioprocesses

Paixão, Susana M.; Arez, B. F.; Silva, Tiago P.; Teixeira, Pedro D.; Alves, Luís Manuel
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em //2014 Português
Zygosaccharomyces bailii strain Talf1, a yeast recently isolated in our laboratory, produces a crude enzymatic extract that was determined to have both inulinase/ invertase activities. The properties of these activities were characterized and the crude extract was applied towards bioprocesses. The extracellular crude enzymatic extract presents activity in a range of temperatures from 20 to 60°C and pH from 4.5 to 7. Optimal pH and temperature was 5.5 and 50°C for both activities, with long-term thermostability at 25-30°C and pH 5.5. Maximal activities on crude were obtained when Jerusalem artichoke (JA) was used as inducer, attaining 18 and 156 U/ml of inulinase and invertase activities, respectively. Z. bailii Talf1 was used for bioethanol production through consolidated bioprocessing using JA juice as the only nutrients medium (~130 g/l total hydrolysable sugars), producing 67 g/l of ethanol and attaining the maximum theoretical yield (0.51 g/g hydrolysable sugars). Moreover, the crude enzymatic extract was applied for fossil fuels biodesulfurization. Thus, two renewable agro-materials, sugar beet molasses (SBM) and JA, were exploited as cheaper carbon sources for a cost-effective dibenzothiophene desulfurization process by Gordonia alkanivorans strain 1B through simultaneous saccharification and fermentation (SSF) approach. SSF with invertases/inulinases permitted an increase in 2-hydroxybiphenyl specific production rate of 19.5% from SBM (2.61 to 3.12 µmol g-1DCW h-1) and 64.6% (5.06 to 8.33 µmol g-1DCW h-1) from JA juice in comparison to acidic hydrolysis. These results highlight the potential of Talf1 as a CBP strain towards bioethanol and of its enzymatic crude towards enhanced biodesulfurization. 

‣ Properties of Anoxybacillus sp. 3M Xylanases and further application towards sugar rich hydrolysates

Alves, Luís Manuel; Ladeira, S. A.; Arez, B. F.; Paixão, Susana M.
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em //2014 Português
This study aimed to optimize the production of xylanases by Anoxybacillus sp. strain 3M, a thermophilic bacterium isolated from terrestrial hot springs (temperature of 90°C) samples collected on S. Miguel, Azores, Portugal, in batch fermentation testing several agroindustrial byproducts as inducer substrates (BSG - Brewer's spent grain, wheat straw, sugarcane bagasse, and corn cobs). In addition, the xylanases produced by this bacterium with the best inducer substrate were characterized for their optimal pH, temperature and stability. The results for xylanase production showed that the higher levels of xylanases were obtained in growth medium containing 1% (w / v) BSG (1.35 U/mL), but the xylanolytic activity was also observed when wheat straw (1.32 U/mL), sugarcane bagasse (0.80 U/mL), corn cobs (0.30 U/mL) and commercial xylan (0.21 U/mL) were used as substrates. The extracellular crude enzymatic extract from Anoxybacillus sp. 3M was then characterized for its optimal temperature and pH and stability. The best enzyme activity was observed at a temperature of 60 ºC and pH 5.3, and the enzyme retained 100% of its original activity after 96 h at 60 °C and pH 7.0. Zymogram of native gel analysis of the different culture supernatants revealed the presence of an enzyme complex with a molecular weight of 420 kDa. This xylanase may be considered as a biocatalyst thermotolerant and it is interesting for biotechnological applications. Further application of Anoxybacillus 3M crude enzymatic extract to BSG and commercial xylan revealed the presence of xylose and xylooligosaccharides...

‣ KOH for enhanced sugarcane bagasse delignification and further production of sugar-rich hydrolyzates by enzymes application

Paixão, Susana M.; Ladeira, S. A.; Arez, B. F.; Martins, M. L. L.; Roseiro, J. Carlos; Alves, Luís Manuel
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em //2014 Português
Lignocellulosic biomass is envisaged as an important raw material for bioethanol production due to its low cost and high availability. Sugarcane bagasse (SCB), a fibrous residue of cane stalks left over after crushing and extraction of the juice from sugarcane; it is one of the largest cellulosic agro-industrial by-products. Tons of SCB are produced in Brazil as a waste of sugar and ethanol industries. This lignocellulosic by-product is a potential renewable source for 2G-bioethanol production. Usually, SCB is pretreated using alkaline and/or acid treatments viewing higher ethanol yields. The main goal of this study was to optimize the delignification of SCB towards the higher availability of glucans and xylans for further enzymatic hydrolysis to obtain sugar-rich syrups that will be more readily fermented to bioethanol. The delignification was carried out by autoclaving the biomass with KOH and the influence of KOH concentration (1-10%) and the autoclave time (10-60 min) were evaluated through a statistical design. Experimental distribution for two factors according to the Doehlert uniform design was used to produce response surfaces. The responses studied in this design were the percentage of hemicellulose, lignin and total polysaccharides. The results showed that from the two factors evaluated...

‣ Ability of Gordonia alkanivorans strain 1B for enhanced desulfurization of dibenzothiophene and its derivatives using fructose as carbon source

Alves, Luís Manuel; Silva, Tiago P.; Fernandes, A. S.; Paixão, Susana M.
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em //2014 Português
In order to keep up the strict sulfur limits on fossil fuels and their derivatives, refineries commonly use a desulfurization method, which combines high temperatures and pressures with molecular hydrogen known as hydrodesulfurization (HDS). However, the effectiveness of HDS to desulfurize recalcitrant organic aromatic compounds such as dibenzothiophene (DBT) or its derivatives is low. Biodesulfurization (BDS) has been described as a promising complementary technique to HDS. Using microorganisms, BDS is able of desulfurize several recalcitrant compounds usually present in fossil fuels at mild temperatures and pressures without hydrogen, making it a simple and eco-friendly process. In this context and based in the fructophilic behavior of the desulfurizing bacterium, Gordonia alkanivorans strain 1B, several recalcitrant sulfur sources were tested in BDS assays using fructose as carbon source. So, strain 1B was used in desulfurization assays testing 4-mDBT, 4,6-dmDBT and 4,6-deDBT, as sulfur source, in comparison with DBT. Growth and desulfurization kinetics using the different sulfur sources were evaluated and the desulfurization rates were determined by GC analysis of x-DBT consumed. The results showed that the strain 1B using fructose as carbon source was able to fully desulfurize all the sulfur compounds tested in less than 121 hours. For 4-mDBT...

‣ Towards the recovery of by-product metals from mine wastes : an X-Ray absorption spectroscopy study on the binding state of rhenium in debris from a centennial Iberian Pyrite Belt mine

Figueiredo, M. Ondina; Silva, Teresa Pereira; Veiga, João Pedro; Oliveira, Daniel P. S.; Batista, Maria João
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Artigo de Revista Científica
Publicado em //2014 Português
Rhenium is a very scarce element, occurring in the Earth's crust mainly carried by molybdenite (MoS2). Due to a very low availability comparative to actual industrial demand, rhenium is nowadays one of the most expensive mineral commodities and an increased interest is focused on exploring residues resulting from a long-term mining, particularly of sulphide ore deposits. It is therefore noteworthy to assign the presence of rhenium (in a concentration up to 3 ppm) in the waste materials from the old sulphur factory at the abandoned mine of São Domingos (Iberian Pyrite Belt, Southeast Portugal), exploited since the Roman occupation of Iberia. Aiming at a potential sustainable recovery of rhenium as a by-product, X-ray near-edge absorption spectroscopy (XANES) was applied to clarify the Re-binding and mode of occurrence by comparing Re L3-edge XANES spectra obtained from mine waste samples (previously fully characterized by X-ray laboratory techniques) with similar spectra collected from Re-rich molybdenites (Mo1-xRexS2) and from Re-O model compounds configuring various valences and coordination environments of rhenium ions. Obtained results are commented, ruling out a possible Re-S binding and rather conforming with the binding of rhenium to oxygen in the analysed mine waste materials.

‣ Tectonic and neotectonic implications of a new basement map of the Lower Tagus Valley, Portugal

Carvalho, João P. G.; Rabeh, Taha; Dias, Rui; Dias, Ruben P.; Pinto, Carlos C.; Oliveira, José Tomás; Cunha, Teresa Arriaga; Borges, José Fernando
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Artigo de Revista Científica
Publicado em /03/2014 Português
In this paper we present a new basement (defined here as Paleozoic, Precambrian and Mesozoic igneous rocks) map of the Lower Tagus Valley area. This map is a contribution to the understanding of the structural evolution of the top of the basement in the Lower Tagus Valley area during the Mesozoic and Cenozoic Eras. The map was produced using aeromagnetic, well, seismic reflection and geological outcrop data. It shows unprecedented details of the geometry of the basement rock's surface with higher resolution and covers a larger area than the previous basement map of the study area. In spite of an estimated average error of 200 m in depth and an horizontal resolution of 4 km, our map not only reproduces with accuracy several well known basement structures but it also emphasizes previously unknown features. Major basement faults were inferred from large depth variations at the top of the basement, magnetic 2D Euler deconvolution and horizontal gradient analysis and are compatible with surface geological structures, well data and hydrogeological information. Implications to the geodynamic evolution of the SW European Variscides and consequences to Meso-Cenozoic tectonics are discussed. The correlation of the basement structures with instrumental seismicity is carried out and their neotectonic activity is discussed on the basis of existing geological outcrop data.

‣ Towards a strategy to zero energy buildings (ZEB) concept

Gonçalves, Helder
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
The energy consumption in buildings and the need for its reduction has been since the late 60’s and 70ś a main question among professionals (designer, architects, and engineers), legislators and users around the word. Reduction in energy demand for heating for instance was implemented in the so called Solar Buildings (with reduction of 70 to 80% in the heating demand). The building regulation start putting targets, in the overall annual energy consumption xx kWh/m2 year, and some achieve the level of standards, imposing very low values, such as Passivhaus standard which fundamentally consists of an energy limit (net useful energy demand for heating of 15 kWh/m²/year and a total primary energy consumption of 120 kWh/m²/year). Now we are dealing for a new concept, in which those values approach zero (ZEB) or even minus, which correspond to building which produce more than what they spend (ENERGY PLUS BUILDINGS). This paper discusses some of the main issues regarding the strategy to achieve some of these goals in the future.

‣ CIMP Faro'09 : II Joint Meeting of Spores-Pollen and Acritarch Subcommissions. Abstracts

Fernandes, Paulo; Pereira, Zélia; Oliveira, José Tomás; Clayton, G.; Wicander, R.
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Livro
Publicado em /09/2009 Português

‣ CIMP Faro'09 : II Joint Meeting of Spores-Pollen and Acritarch Subcommissions. Palynostratigraphic contributions to the understanding the Southwest Portugal and Algarve Basin Geology, Portugal : Post Meeting Field-Trip, 23-24 September 2009

Oliveira, José Tomás; Fernandes, Paulo; Pereira, Zélia; Borges, Marisa
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Livro
Publicado em /09/2009 Português

‣ Matter under extreme conditions in the earth's interior : a challenge for physicists and mineralogical crystallographers

Figueiredo, M. Ondina
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em /07/2009 Português

‣ Optimisation of preparation and measurement protocols for luminescence dating of small samples from a suite of porcelains and faiences

Burbidge, Christopher Ian; Rodrigues, Ana L.; Dias, M. Isabel; Prudêncio, M. Isabel; Cardoso, Guilherme; Figueiredo, M. Ondina; Silva, Teresa Pereira; Matos, Maria Antónia; Pais, Alexandre Manuel
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em /09/2009 Português

‣ Silurian to Lower Devonian palynomorphs from the Barrancos region, Ossa Morena Zone, Portugal : preliminary results

Lopes, Gilda; Pereira, Zélia; Fernandes, Paulo; Piçarra, José Manuel; Oliveira, José Tomás
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em //2009 Português

‣ New Lower Givetian age Miospores of the Phyllite-Quartzite Group, São Francisco da Serra anticline, Iberian Pyrite Belt, Portugal

Pereira, Zélia; Matos, João Xavier; Fernandes, Paulo; Jorge, Raul; Oliveira, José Tomás
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em //2009 Português

‣ Simulating antigenic drift and shift in influenza A

Fachada, Nuno; Lopes, Vitor V.; Rosa, Agostino
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em 08/03/2009 Português
Computational models of the immune system and pathogenic agents have several applications, such as theory testing and validation, or as a complement to first stages of drug trials. One possible application is the prediction of the lethality of new Influenza A strains, which are constantly created due to antigenic drift and shift. Here, we present an agent-based model of immune-influenza A dynamics, with focus on low level molecular antigen-antibody interactions, in order to study antigenic drift and shift events, and analyze the virulence of emergent strains. At this stage of the investigation, results are presented and discussed from a qualitative point of view against recent and generally recognized immunology and influenza literature.

‣ Reactive versus Latching Phase Control of a Two-body Heaving Wave Energy Converter

Falcão, António F. de O.; Justino, Paulo Alexandre; Henriques, João C.C.; André, José M.C.S.
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em /08/2009 Português
The paper deals with the modelling, optimization and control of the IPS buoy wave energy converter, a two-body point-absorber oscillating in heave, consisting of a floater rigidly connected to a long submerged vertical acceleration tube open at both ends within which a piston can slide, forcing the motion of the inside water below and above it. Energy is converted from the relative motion between the piston and the buoy-tube pair. The modelling is performed in the frequency domain (including reactive phase control), in order to provide some kind of geometry optimization, and also in the timedomain to allow the simulation of a more realistic highpressure- oil power take-off system.