Petrography and geochemistry of Sepeda Li-rich aplite-pegmatite dyke swarm (Montalegre, N Portugal)

The Sepeda aplite-pegmatite dyke swarm is situated in the Barroso-Alvão region (Montalegre, Northern Portugal) and is currently a strategic Li ore deposit in Europe. Geologically, it is located in the Parautochthonous Thrust Complex of the Galicia-Trás-os-Montes Zone (Variscan Iberian Belt), more exactly on its southern edge, next to the Central-Iberian Zone. Numerous aplitic and pegmatitic bodies, considered of the LCT type (e.g. Noronha et al., 2013), that cross cut the host metasediments of Silurian age were recently targeted in a diamond drilling campaign. From 4 drill hole logs with suspected Li mineralizations, 120 samples were selected for whole-rock chemical analysis and also 13 samples for thin section preparation. Petrographically, the Sepeda pegmatitic rocks are characterized by distinctive igneous textures that include the following major crystalline phases: K-feldspar, plagioclase, quartz, muscovite, petalite and spodumene. The latter is commonly altered to other Li bearing minerals such as eucryptite and cookeite. The most common accessory minerals are the phosphates montebrasite and apatite and the opaques cassiterite and sphalerite. Aditionally, there are strong evidence of solid state deformation like the dynamic recrystalization of quartz and bent muscovites in addition to plagioclase and K-feldspar flexured twins. In relation to whole-rock geochemistry, these intrusive rocks are mainly felsic with SiO2 contents ranging between 60,97 and 85,78%. The lithologies of intermediate compositions are mostly the aplitic types occuring at shallower depths. With regards to Li2O, the concentration interval varies from 0,01 up to 4,13% where the richer samples (>1% of Li2O) are the pegmatites with aproximately 74% of Si2O in which petalite is the major constituent. Other relevant trace element is Sn reaching 2100 ppm in opposition to Cs (1,68 - 191,50 ppm) and Ta (1,10 - 97,40 ppm). They also show low concentrations in ΣREE (1,37 - 5,61 ppm) with strongly variable Eu anomalies (0,36 ≤ Eu/Eu* ≤ 2,98).publishe

Application of Visual-Inertial SLAM for 3D Mapping of Underground Environments

The underground scenarios are one of the most challenging environments for accurate and precise 3d mapping where hostile conditions like absence of Global Positioning Systems, extreme lighting variations and geometrically smooth surfaces may be expected. So far, the state-of-the-art methods in underground modelling remain restricted to environments in which pronounced geometric features are abundant. This limitation is a consequence of the scan matching algorithms used to solve the localization and registration problems. This paper contributes to the expansion of the modelling capabilities to structures characterized by uniform geometry and smooth surfaces, as is the case of road and train tunnels. To achieve that, we combine some state of the art techniques from mobile robotics, and propose a method for 6DOF platform positioning in such scenarios, that is latter used for the environment modelling. A visual monocular Simultaneous Localization and Mapping (MonoSLAM) approach based on the Extended Kalman Filter (EKF), complemented by the introduction of inertial measurements in the prediction step, allows our system to localize himself over long distances, using exclusively sensors carried on board a mobile platform. By feeding the Extended Kalman Filter with inertial data we were able to overcome the major problem related with MonoSLAM implementations, known as scale factor ambiguity. Despite extreme lighting variations, reliable visual features were extracted through the SIFT algorithm, and inserted directly in the EKF mechanism according to the Inverse Depth Parametrization. Through the 1-Point RANSAC (Random Sample Consensus) wrong frame-to-frame feature matches were rejected. The developed method was tested based on a dataset acquired inside a road tunnel and the navigation results compared with a ground truth obtained by post-processing a high grade Inertial Navigation System and L1/L2 RTK-GPS measurements acquired outside the tunnel. Results from the localization strategy are presented and analyzed

Towards a Mobile Three-dimensional Modelling System for Underground Structures

Robotica 2012: 12th International Conference on Autonomous Robot Systems and Competitions April 11, 2012, Guimarães, PortugalThis paper addresses the three-dimensional modelling of large scale underground galleries, such as traffic tunnels and mines. This work employs techniques from mobile robotics to achieve an autonomous mobile modelling system, adapted to general underground environments. So far, the state-of-the-art methods in underground modelling remain restricted to environments in which pronounced geometric features are abundant. This limitation is a consequence of the scan matching algorithms used to solve the localization and registration problems. This work aims to extend the modeling capability to structures characterized by uniform geometry and smooth surfaces, as is the case of road and train tunnels. A visual monocular Simultaneous Localization and Mapping (MonoSLAM) approach based on the Extended Kalman Filter (EKF) and complemented by the introduction of inertial measurements in the prediction step, allows our system to build threedimensional models and localize himself over long distances, using exclusively sensors carried on board a mobile platform. By feeding the Extended Kalman Filter with inertial data we were able to overcome the major problem related with MonoSLAM implementations, known as scale factor ambiguity, which emerges from the absence of metric measurements in monocular images. The monocular visual features used in MonoSLAM were extracted by the SIFT algorithm, and inserted directly in the EKF mechanism according to the Inverse Depth Parametrization. Through the 1-Point RANSAC (Random Sample Consensus) wrong frame-to-frame feature matches were rejected. To build the model, vertical cross-sections of the gallery, acquired by a laser range finder sensor, are placed on a common reference frame using the estimated localization. The system was tested based on a dataset acquired inside a real road tunnel. Results from the localization strategy and the modelling process are presented

Geologia da região de Granja (Brasil) e potenciais recursos de rochas ornamentais

Mestrado em Geomateriais e Recursos GeológicosO Complexo de Granja (CG), localizado no Domínio Médio Coreaú (NW Ceará, Brasil), corresponde a um cinturão metamórfico de médio a alto grau, composto por três unidades principais: (1) ortognaisses migmatizados de afinidade TTG (Tonalito-Trondhjemito-Granodiorito); (2) paragnaisses diatexíticos e; (3) granulitos máficos e félsicos. De acordo com os dados geocronológicos actualmente disponíveis, estas sequências representam um segmento do soco Paleoproterozóico (2.3-2.1 Ga), profundamente afectado pela orogenia Brasiliana durante o Neoproterozóico (» 600 Ma). Os principais objectivos da investigação realizada no âmbito desta tese consistiram em: (a) proceder à cartografia detalhada das diferentes unidades do CG e reconstituir a geometria das estruturas produzidas durante a deformação brasiliana, em particular as associadas ao último evento de deformação; (b) estudar as principais modificações mineralógicas e texturais induzidas pelo metamorfismo regional prógrado nas rochas do CG; (c) propor um modelo explicativo para a evolução tectono-metamórfica da região e, finalmente, (d) caracterizar tecnologicamente amostras de ortognaisses TTG e de paragnaisses diatexíticos com vista a avaliar o seu potencial interesse para utilização como rochas ornamentais. Com base nos dados de campo, no estudo petrográfico e na análise microestrutural das relações blastese/deformação foi possível elaborar um novo mapa geológico para a área em investigação, usando o suporte “ARCGIS” da “ESRITM” e propor um modelo preliminar para a evolução geodinâmica deste segmento do cinturão orogénico brasiliano. Outros dos resultados relevantes deste projecto foram: (a) a caracterização petrográfica e tecnológica de algumas das rochas do CG e (b) a elaboração de uma proposta de plano de viabilização económica para uma lavra piloto. A informação obtida demonstrou que estes materiais satisfazem todos os requisitos necessários para futura exploração como rochas ornamentais.The Granja Complex (GC), located in the Médio Coreaú Domain (NW Ceará, Brasil) corresponds to a medium to high grade metamorphic belt consisting of three main units: (1) Tonalite-throndjemite-granodiorite orthogneisses - TTG; (2) Diatexitic garnet-sillimanite bearing paragneisses and (3) Mafic and felsic granulites. According to the published geochronological data, these sequences represent a segment of the Paleoproterozoic basement (2.3-2.1 Ga), intensely metamorphosed and deformed during the Brasilian orogeny in the Neoproterozoic (» 600 Ma). The main objectives of the investigation carried out in the scope of this thesis can be summarized as follows: (a) to map in detail the different GC units and to establish the geometry of the structures produced during the Brasilian deformation, particularly those related to the last deformation event; (b) to study the main mineralogical and textural changes induced by high-grade regional metamorphism in the GC; (c) to propose a tectono-metamorphic model for the studied area and, finally, (d) to perform the technological characterization of samples from the TTG orthogneisses and the garnet-sillimanite paragneisses in order to evaluate their potential interest as decorative dimension stones. Based on field data, petrography and micro-structural analysis, it was possible to draw a new geological map for the studied area, using the ARCGIS (ESRITM) application and propose a preliminary model for the geotectonic evolution of this segment of the Brasilian orogenic belt. Other relevant outcomes of this project are. (a) the technological characterization of some GC rocks and (b) the elaboration of a proposal for an economic feasibility plan for their exploration. The results obtained show that the prospects fulfill all the qualitative, technical and economic requirements for future exploration as dimension stone

Sobre a avaliação do conhecimento gramatical escolar : um estudo dos exames nacionais de português de 2009

Se aceitamos que “a avaliação é sinónimo de sucesso” (Pacheco & Zabalza, 1995: 7), ao estudar a problemática da avaliação e entendendo a avaliação oficial como um factor constitutivo da disciplina de Português, discutiremos como são representados e avaliados os conhecimentos explícitos sobre a língua materna. Assim, na sequência de um outro trabalho sobre a avaliação gramatical (Silva, no prelo), pretendemos, com o presente artigo, continuar o estudo do domínio da gramática em provas de avaliação externa, identificando o conhecimento gramatical oficialmente avaliado. Neste sentido, o objectivo principal deste texto é o de caracterizar a configuração do conhecimento gramatical nos exames nacionais de Português realizados em 2009. Para debater tais questões, este trabalho desenvolve-se em duas partes: a) apresentação das dimensões do estudo das provas de avaliação externa de Português; b) discussão e análise dos dados, com a apresentação dos primeiros resultados do estudo das provas de avaliação de Português realizadas em 2009. As conclusões de um trabalho desta natureza deverão apontar no sentido de uma melhor compreensão do papel da regulação externa dos saberes relativos ao conhecimento explícito da língua, ao mesmo tempo que nos permitirão determinar as novas formas de configuração da gramática escolar portuguesa

A importância do estudo da difusão alvéolo-capilar, como complemento da pletismografia, na avaliação funcional de fumadores

AbstractThis study comprised 194 male and female heavy smokers or ex-smokers (≥ 1 pack-year) aged between 20 and 82, whose symptoms varied. Cases were only selected from patients with normal whole-body plethysmography. Subjects with any significant pathology and occupational risk factors were excluded from the study.Varying degrees of symptoms were found and a range of results from normal plethysmography examination, with abnormal levels of alveolar-capillary transfer, determined by the single-breath method to analyse CO (TLCO and TLCO -VA) coefficients. Using the chi-square test for statistical analysis of the sample revealed a significant variation in sensitivity between both parameters (p=0.0001).Possible limitations of using the single-breath method, of were reduced in this study (ventilatory restriction withVital Capacity <1.5 litres) by the routine plethysmography results seen. Likewise, the presence of alterations in ventilatory distribution was, in principle, minimised by the absence of TLCsb/TLCplet values below 0.85%Conclusions: Normal plethysmography results in heavy or ex-smokers are not enough to confirm normal respiratory function, as a large percentage of cases present abnormalities in the alveolar-capillary transfer factor for CO. Alveolar limitation was considered not only anatomically, but also from a functional perspective.Rev Port Pneumol 2007; XIII (6): 763-77

O desenvolvimento de significados das letras na aprendizagem de equações literais

Nesta comunicação aborda-se a questão do desenvolvimento de significados das letras na aprendizagem de equações literais, explorada no âmbito de uma intervenção pedagógica supervisionada do curso de Mestrado em Ensino de Matemática no 3º Ciclo do Ensino Básico e no Ensino Secundário, da Universidade do Minho. A intervenção de ensino, implementada pelo primeiro autor e supervisionada pelos dois outros autores, decorreu numa turma do 8º ano de escolaridade no ano letivo de 2011/2012, durante sete blocos de 90 minutos e incidiu sobre o tema Equações literais e Polinómios, embora neste texto apenas nos referimos às Equações literais. Neste último caso, o desenvolvimento de significados das letras foi incentivado através da exploração de tarefas contextualizadas, relacionadas com situações da realidade, de modo a levar os alunos a ligarem as letras a referentes desses contextos. Apesar da análise das primeiras tarefas exploradas nas aulas mostrar que os alunos tinham dificuldade em atribuir significado às expressões e às letras envolvidas nas equações, o que revela a dificuldade dos alunos face ao uso e interpretação das letras, com o progresso da intervenção de ensino verificou-se que os alunos se tornaram mais capazes de atribuir significados às letras e de manipularem expressões e equações com várias letras. Para essa evolução dos alunos terá contribuído a ênfase dada ao tipo de tarefas exploradas, uma visão da Matemática associada ao desenvolvimento de capacidades e à construção de conhecimentos e uma perspetiva de ensino e aprendizagem centrada no aluno

Improving The Order Fulfilment Process At A Metalwork Company

This article describes the 14 measures implemented at a company in the metalwork sector with a view to improving its order fulfilment process. Based on Lean thinking, each of the actions, as well as their potential impact on the process, is explained. Despite the constraints encountered during implementation, and the fact that manufacturing processes are invariably different, the overall results achieved were satisfactory. As a result of the interventions, internal functions were revised and processes simplified. There was also a reduction of 25% in budgeting time, as well as an improvement in communication systems and production management. One additionally was achieved the reorganization of storage spaces, a reduction in logistic operation times of about 20% and a decrease in the time spent accessing tools in near 61%. Far more important than the first results obtained is the company’s current commitment to the pursuance of these measures, allowing the different actions to generate synergies and produce improvements, which will undoubtedly set the company on the course of Lean culture.info:eu-repo/semantics/publishedVersio

A model for the Portuguese tourism market

The discussion of tourism problems is classical and many developments have brought tourism models to the actual debate. In a moment when global crisis is painful for many economies mainly in many developed countries, this topic is now particularly relevant. In this study, factors explaining demand, supply and prices are discussed. At macroeconomic level, it is seen how they contribute to model the Portuguese tourism market. A relationship among the variables is analyzed and its modeling is represented mathematically. The model allows us to conclude about the contribution of this kind of model to show the importance of these variables and relationships to the determination of the macroeconomic aggregates in the Portuguese tourism market