A continuous-stress tetrahedron for finite strain problems

A finite-strain tetrahedron with continuous stresses is proposed and analyzed. The complete stress tensor is now a nodal tensor degree-of-freedom, in addition to displacement. Specifically, stress conjugate to the relative Green-Lagrange strain is used within the framework of the Hellinger-Reissner variational principle. This is an extension of the Dunham and Pister element to arbitrary constitutive laws and finite strain. To avoid the excessive continuity shortcoming, outer faces can have null stress vectors. The resulting formulation is related to the nonlocal approaches popularized as smoothed finite element formulations. In contrast with smoothed formulations, the interpolation and integration domain is retained. Sparsity is also identical to the classical mixed formulations. When compared with variational multiscale methods, there are no parameters. Very high accuracy is obtained for four-node tetrahedra with incompressibility and bending benchmarks being successfully solved. Although the ad-hoc factor is removed and performance is highly competitive, computational cost is high, as each tetrahedron has 36 degrees-of-freedom. Besides the inf-sup test, four benchmark examples are adopted, with exceptional results in bending and compression with finite strains

Correlation of magnetic susceptibility with 18O data in magnetite- and ilmenite-type granites from Iberian massif

The relationship between oxygen isotopic values and magnetic susceptibility composition on 11 Variscan Portuguese granites has been investigated. Whole-rock oxygen-isotope (18O ) values for Vieira do Minho (VM), Vila Pouca de Aguiar (VPA), Chaves, Castelo Branco (CB), Manteigas and Serra da Estrela (SE) granitoids, were compilated from bibliography [1,2,3,4], and 18O for Santa Eulalia Plutonic Complex (SEPC) were obtained by laser fluorination at the Stable Isotopic Laboratory of Salamanca. Magnetic susceptibility (Km) values were obtained with a Kappabridge equipment from Toulouse University and Geology Centre, Porto University [2,5,6,7,8]. In this study is shown that there is a significant inverse correlation between Km and 18O. Magnetite-type granites (Manteigas granodiorite and SEPC external facies) have Km>10-3 SI and low 18O values ranging from 8.9 to 10.3 0/00 instead those of ilmenite-type (all the other granites) have Km 10-4 SI and are 18O enriched (9.3 to 13.5 0/00). The I-type granites (VM, VPA, Chaves, Manteigas and SEPC external facies) show lower average 18O (10.2 0/00) and higher Km values (100x10-6 SI) than the S-type granites (SE and CB) with 18O = 12.6 0/00 and Km = 65x10-6 SI. Figure 1: Semi-log plot of Km (in Si units) versus 18O. This work has been financially supported by PTDC/CTEGIX/ 099447/2008 (FCT-Portugal, COMPETE/FEDER). [1] Martins et al. (in prep.) [2] Martins et al. (2009) Lithos 111, 142-155. [3] Antunes et al. (2008) Lithos 103, 445-465. [4] Neiva et al. (2009) Lithos 111, 186-202. [5] Sant’Ovaia et al. (2010) JSG 32, 1450-1465. [6] Sant’Ovaia et al. (2000) TRSE, ES 91, 123-127. [7] Sant’Ovaia et al. (2008) 33rd IGC CD. [8] Sant’Ovaia et al. (2011) Min. Mag. 75, 3, 1795

Solid-phase extraction of nitro-PAH from aquatic samples and its separation by reverse-phase capillary liquid chromatography

In this work, an analytical methodology to extract 1-nitronaphthalene, 2-nitrofluorene, 9-nitroanthracene, 3-nitrofluoranthene, and 1-nitropyrene aquatic samples is proposed. Capillary liquid chromatography with on-column UV detection (µLC-UV) was employed to separate and quantitate all five nitrated polycyclic aromatic hydrocarbons (nitro-PAH) extracted from water samples. Two different extraction techniques were tested and compared: liquid-liquid extraction (LLE) and solid phase extraction (SPE) with two different sorbents, octadecylsilica (C18) and styrene divinylbenzene (XAD-2) particles. The elution of analytes was tested with both acetonitrile and methylene chloride. The best recovery results were obtained for SPE-C18 extraction with the methylene chloride with values ranging from 76 to 97% with RSD values smaller than 4%. The chromatographic conditions for analysis was carried out using a 250 × 0.3 mm i.d. packed capillary column with 5 µm C18 particles. The elution was isocratic with 65% acetonitrile in water (v/v) as mobile phase with a flow rate of 7 µL min-1. The detection limits due to on-column UV detection (ranging ~3-30 mmol L-1) are limiting for environmental applications, however, they are suited for toxicological studies

Estruturas de Produção do Documentário Português. Estudo de caso no Doclisboa – Festival Internacional de Cinema Documental de Lisboa

Esta dissertação analisa as estruturas de produção dos documentários portugueses patentes nas três primeiras edições (2002, 2004 e 2005) do Doclisboa – Festival Internacional de Cinema Documental de Lisboa. O estudo empreende um levantamento e avaliação da dimensão económica, sociológica e tecnológica da actividade cinematográfica através da análise dos sistemas de financiamento e das relações de trabalho das equipas técnicas e artísticas. Na prossecução deste objectivo são delineadas e enquadradas as esferas do profissional e do artesanal da respectiva actividade produtiva. A investigação dá um maior enfoque na actividade artística e laboral do realizador, como elemento central da estrutura de produção. A estratégia metodológica adoptada visa apreender as inovações e transformações tecnológicas operadas no domínio do digital e a consequente afectação do campo produtivo. Aborda-se a problemática inerente entre a aceleração e massificação da tecnologia digital e a sustentabilidade das estruturas de produção da actividade cinematográfica documental portuguesa. Percorre-se de modo sucinto alguns momentos da história do documentário português realçando o movimento documentarista dos anos 90. São expostos os seus méritos e as suas dificuldades, características ainda hoje presentes e influentes na produção contemporânea. No quadro teórico é proposta uma reflexão em torno da ontologia do documentário, evidenciando a sua componente criativa e as questões de representatividade numa época e implementação da imagem digital.This dissertation analyses the production structures of the Portuguese documentaries within the three first editions (2002, 2004 and 2005) of Doclisboa – Festival Internacional de Cinema Documental de Lisboa (Lisbon International Documentary Cinema Festival). The study surveys and assesses the economic, sociological and technological dimension of the cinematic activity by analysing the financing systems and work relations of the technical and artistic teams. In the pursuit of this aim the professional and non-professional spheres of the respective productive activity are outlined and framed. The investigation emphasizes the artistic and working activity of the director as central element to the production structure. The adopted methodology aims at understanding the technological innovations and changes carried out within the digital domain and the consequent effect on the production field. The inherent problems between acceleration and massification of digital technology and the sustainability of the production structures of Portuguese documentary cinematography are approached. Some history moments of Portuguese documentaries are summarised giving emphasis to the documentary movement of the 90s. Its merits and difficulties are exposed, characteristics which are still present nowadays and influence the production of our time. Concerning theory, a reflection is proposed on the documentary ontology, emphasizing its creative component and representation matters in a time and implementation of digital image

A New Online Intensity Data Point Database for Portugal

Online macroseismic intensity databases are becoming common tools in the framework activities related to seismic hazard assessment as they can offer a consistent information background. In Europe, institutions such as INGV (IT), ETH (CH) and Sisfrance (FR) have well-established Macroseismic Intensity Databases. In the framework of the EC projects NERIES (2006-2010) and SHARE (2009-2012), the European "Archive of Historical EArthquake Data" AHEAD was established. Other European institutions are now in the process of creating their own intensity databases following such a proposed common standard. Portugal is among those countries working on a macroseismic intensity database, as at present an updated general compilation of the mainland Portugal macroseismicity is still unavailable. The IM, has among its short term objectives to compile a macroseismic database and to give free access to it on the web. To manage it, the MIDOP software, created and developed by the Italian INGV has been selected. It allows easy access to earthquake listing and visualization of geographical distribution of intensity data points through a web page without the need of installing a complex infrastructure. MIDOP underlying structure strictly follows the standard proposed by AHEAD and with its adoption the collected data will be compatible with other national databases. The status of the project is here presented

Third Generation Tsunami scenario matrix for the Portuguese Tsunami Early Warning System

In Portugal, the Instituto de Meteorologia (IM) is the institution responsible for the Portuguese seismic network and it is the candidate to host the Portuguese Tsunami Warning System. One critical component of the system is the scenario database and the Tsunami Analysis Tool that help the operator to take decisions during the course of the event. This paper describes the progress done since 2008 conducting to the 3rd generation of the scenario database that provides a higher resolution modeling at the coastline for the whole North Atlantic. The 3rd generation scenarios are initiated by a simulation domain with a coarse bathymetry cell size (2 min). This initial calculation establishes the adequate initial and boundary conditions to 3 other domain calculations with a much finer cell size (0.25 min). The high-resolution calculation is performed only close to the coast in order to reduce the CPU time.JRC.G.2-Global security and crisis managemen

Petrogenesis of the Santa Eulália Plutonic Complex (Alentejo, Portugal): contribution from recent elemental and isotopic (Sr-Nd) geochemical data

The Santa Eulalia Plutonic Complex (SEPC) is a late-Variscan granitic massif with elliptical contours intersecting the NW-SE Variscan dominant regional structures in the most northerly sectors of the Ossa-Morena Zone (Iberian massif). The host rocks of this plutonic complex are meta-sedimentary formations generated between Proterozoic and Lower Paleozoic, some of them strongly affected by contact metamorphic processes related to the SEPC intrusion, and now recognized as a set of hornfels with a wide compositional range. SEPC has two main granitic facies which present different compositions and textures. It can be classified as a ring igneous complex composed, from the rim to the core, by a medium- to coarse-grained pink granite (G0-group), with biotite ( horneblende) as the dominant mafic mineral, involving large (kilometric) elongated masses of mafic (gabbroic) to intermediate (granodioritic) rocks, here called M-group, and a central gray medium-grained granite (G1-group), typically monzonitic, with biotite as the main mafic mineral, sometimes showing a slight porphyritic tendency, namely in a few outcrops located in transitional zones, near the contact with the peripheral G0-type ring. Magnetic Susceptibility (MS) analysis sustain major genetic differences between pink and gray SEPC granites. G0 facies present relatively high values of magnetic susceptibility (Km>10-3 SI) compatible with the presence of magnetite, while the low values registered in G1-group (Km<10-4 SI) are consistent with the presence of ilmenite. Distinct magnetic behaviour of these two granitic facies also reveal contrasting redox conditions during the magma genesis and cooling process (Sant’Ovaia et al., 2011). Elemental geochemistry confirms significant differences between G0 and G1 facies. G0 granites represent more evolved liquids (>SiO2 wt.% and <MgO wt.%) with dominant metaluminous character, plot close to A-type fields (Whalen et al., 1987), and some samples show negative Eu anomalies. Instead, G1 facies are typically monzonitic granites with a slight peraluminous character and no significant Eu anomalies (Lopes et al., 1998). Relationships between SiO2 vs. (Na2O+K2O-CaO) indicate that G0-group and G1-group have alkali-calcic and calc-alkaline character respectively; both granitic groups, should be classified as magnesian according to SiO2 vs. FeOt/(FeOt+MgO) correlation (Frost et al., 2001). Recent Sr and Nd isotopic data obtained for 15 samples (5 per group of facies) were used considering an age around 290 My (Pinto, 1984). The least evolved gabbro of the M-group has a mantle Nd isotopic signature (ɛNd290=+1.7) representing the highest value of the wide ɛNdi range revealed by this group of facies (-3.0<ɛNd290<+1.7). Representative samples of G0 granite, belonging to the external ring, show a narrower range of ɛNdi values (-2.3<ɛNd290<-0.9) which is included in the previous M-group ɛNdi range. G0-group also plots in the mantle-crust Sr-Nd isotopic alignment apparently defined by mafic-intermediate rocks of M-group. In contrast, the grey granites placed in the central part of the SEPC (G1-group), diverge from this trend, showing clearly lower ɛNd290 values (-5.9<ɛNd290<-4.7) which suggest petrogenetic processes involving dominant crustal melts and/or primary magmas strongly contaminated by crustal fractions. Also (87Sr/86Sr)290 vs. (1/Sr) projection points to a likely ACF-type differentiation process showing that crustal assimilation were probably more important during the petrogenesis of the G1-facies than in the magmatic event which provided the association between M and G0 groups, probably dominated by fractional crystallization mechanisms with relatively lower contribution of crustal assimilation

Project WILAS – West Iberia Lithosphere and Astenosphere Structure

The lithosphere of Iberia has been formed through a number of processes of continental collision and extension: in Lower Paleozoic, the collision of three tectonics blocks produced the Variscan Orogeny, the main event of formation of the lithosphere. The subsequent Mesozoic rifting and breakup of the Pangea had a profound effect on the continental crust of Iberia. Since the Miocene, the southern interaction between Africa and Iberia is characterized by a diffuse convergent margin that originates a vast area of deformation. The impact of this complex tectonic in the structure of the Lithosphere remains an incognito, especially in its western part. Project WILAS (PTDC/CTE-GIX/097946/2008) is a 3 years project funded by FCT in which a temporary network of more than 20 BB seismic stations is being deployed in Portugal between 2010-2012. It will extend to the western border of Iberia the coverage of the TOPO-IBERIA project. The project aims to image the 3D structure beneath W Iberia. The knowledge of the Crust, Lithosphere and Astenosphere seismic structure must be dealt at different scales, involving different but complementary methods

Petrofísica e Geoquímica no Complexo Plutónico de Santa Eulália

O Complexo Plutónico de Santa Eulália (CPSE) é um corpo granítico calco-alcalino situado na parte norte da Zona da Ossa Morena do maciço Ibérico Varisco. O complexo é considerado tardi-Varisco, uma vez que corta estruturas regionais variscas. O CPSE é um complexo anelar onde podem identificar-se, da periferia para o centro: (i) uma fácies granítica de cor rosa e grão médio a grosseiro (G0) que envolve corpos de composição gabróica a granodiorítica (grupo-M); (ii) uma fácies central de granito cinzento monzonítico de grão médio (G1). Neste trabalho apresentam-se resultados de um estudo que inclui: (i) anisotropia da susceptibilidade magnética (ASM); (ii) magnetização remanescente isotérmica (MRI); (iii) geoquímica isotópica (Nd e O); (iv) orientação dos planos de inclusões fluidas (PIF). Os dados de ASM e MRI suportam o comportamento magnético distinto das duas fácies: G0 com suscetibilidade >10-3 SI e MRI1T=2042.1 mA/m, é controlado por uma fração ferrimagnética (magnetite ou titanomagnetite); G1 com suscetibilidade 5% no granito G0 e <3% no granito central G1. A elevada anisotropia de G0 é justificada pela presença de magnetite mas as observações petrográficas indicaram microestruturas indicativas de deformação pós-magmática. As foliações magnéticas são subverticais e com direcção ENE-WSW em G0 e G1. As lineações magnéticas são subverticais na fácies G0 e mergulham moderadamente para SE na fácies G1. Em termos geoquímicos os granitos G0 representam líquidos magmáticos mais evoluídos (>SiO2 e <MgO, % peso) do que os materializados pelos granitos G1. Assumindo uma idade de 290 Ma para o CPSE, os dados isotópicos de Nd revelam valores compatíveis com uma origem mantélica para a fácies gabróica menos evoluída do grupo M (ɛNd290=+1.7). O intervalo definido pelo grupo M (-4.0<ɛNd290<+1.7) inclui os valores obtidos nos granitos G0 (-2.7<ɛNd290<-1.9), divergindo dos resultados revelados pelos granitos G1 (-5.9<ɛNd290<-5.7). Estes dados isotópicos sugerem que o CPSE se terá gerado por processos de diferenciação de tipo ACF com contribuições crustais mais significativas no grupo G1 do que no conjunto formado pelas fácies M e G0, situadas na periferia do CPSE. Há uma relação inversa entre os valores da suscetibilidade de G0 e G1 e os valores de δ18O destas fácies, o que está de acordo com o obtido para outros granitos variscos indicando que os granitos da série "magnetite-type” têm valores mais baixos de δ18O relativamente aos “ilmenite-type” que são enriquecidos em δ18O. Os PIF indicam a existência de campos de tensões distintos nas duas fácies, durante os episódios de tectónica tardia, frágil. Estas direções são compatíveis com as estruturas regionais no caso da fácies G0, com direção predominante NW-SE e com o campo de tensões tardi-varisco, regionalmente com direção NE-SW no caso da fácies G1. O comportamento e fabric magnético e a geoquímica isotópica diferentes refletem processos petrogenéticos distintos assim como diferentes mecanismos de instalação para as duas fácies G0 e G1. Este trabalho é financiado pelo projeto PTDC/CTE-GIX/099447/2008 (FCT-Portugal, COMPETE/FEDER)

Evaluation of a simple hyphenated system for flow injection solid-phase pre-concentration and capillary electrophoresis

In this work, the development and evaluation of a hyphenated flow injection-capillary electrophoresis system with on-line pre-concentration is described. Preliminary tests were performed to investigate the influence of flow rates over the analytical signals. Results revealed losses in terms of sensitivity of the FIA-CE system when compared to the conventional CE system. To overcome signal decrease and to make the system more efficient, a lower flow rate was set and an anionic resin column was added to the flow manifold in order to pre-concentrate the analyte. The pre-concentration FIA-CE system presented a sensitivity improvement of about 660% and there was only a small increase of 8% in total peak dispersion. These results have confirmed the great potential of the proposed system for many analytical tasks especially for low concentration samples.Nesse trabalho apresentamos um sistema hifenizado envolvendo as duas técnicas analíticas: eletroforese capilar (CE) e análises por injeção em fluxo (FIA), denominado de FIA-CE. Parâmetros como a influência do fluxo e a natureza do eluente frente ao sistema CE foram avaliados. O sistema demonstrou-se promissor quanto à possibilidade de aplicações em diferentes áreas da química analítica. O aumento da sensibilidade foi da ordem de 660% devido ao emprego de colunas de troca iônica no sistema FIA. Esse resultado comprova o grande potencial do sistema FIA-CE.Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)CNPqFAPES