1,326 research outputs found

    Use of dialkyldithiocarbamato complexes of bismuth(III) for the preparation of nano- and microsized Bi2S3 particles and the X-ray crystal structures of [Bi{S2CN(CH3)(C6H13)}(3)] and [Bi{S2CN(CH3)(C6H13)}(3)(C12H8N2)]

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    A range of bismuth(III) dithiocarbamato complexes were prepared and characterized. The X-ray crystal structures of the compounds [Bi{S2CN(CH3)(C6H13)}3] (1) and [Bi{S2CN(CH3)- (C6H13)}3(C12H8N2)] (2) are reported. The preparation of Bi2S3 particulates using a wet chemical method and involving the thermalysis of Bi(III) dialkyldithiocarbamato complexes is described. The influence of several experimental parameters on the optical and morphological properties of the Bi2S3 powders was investigated. Nanosized Bi2S3 colloids were obtained having long-term stability and showing a blue shift on the optical band edge; the presence of particles exhibiting quantum size effects is discussed. Morphological welldefined Bi2S3 particles were obtained in which the fiber-type morphology is prevalent.FCT - POCTI/1999/CTM/ 3545

    Petrophysical and geochemical characterization of the late-variscan Santa Eulália Plutonic Complex (Ossa-Morena Zone, Portugal)

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    The Santa Eulália Plutonic Complex (SEPC) is a calc-alkaline granitic body located in the northern part of the Ossa Morena Zone, composed by a medium- to coarse-grained pink granite (G0 group) involving large elongated masses of mafic (gabbroic) to intermediate (granodioritic) rocks, M group, and a central gray monzonitic granite (G1 group) which present dominant medium granular facies. A multidisciplinary study, including petrophysical, AMS and IRM measurements, and geochemical data, elemental and isotopic (Nd and 18O), point out differences in magnetic behaviour, magnetic lineations patterns and geochemical features, reflecting distinct petrogenetic processes at the level of the magmatic sources and evolution, as well as the emplacement mechanisms of M, G0 and G1 facies associated in the SEPC

    O Papel do Ambiente Físico e Social na Construção de Comunidades Saudáveis. Ensaio Metodológico Aplicado à Amadora

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    O reconhecimento do papel do ambiente na determinação da qualidade de vida e da saúde atribuiu ao lugar a capacidade de explicar os padrões de vida, saúde, doença e morte dos indivíduos. Nesta perspectiva, vários estudos concluem que as situações de vulnerabilidade formam clusters, sugerindo uma amplificação do risco identificada pela simultaneidade de vários factores, sobressaindo lugares onde residem pessoas envelhecidas, pouco instruídas, doentes, com alojamentos precários e escassez de oportunidades locais capazes de proporcionar vidas mais saudáveis e até de transportes públicos que permitiriam a deslocação e obtenção de serviços e bens noutros locais. Este texto procura avaliar áreas de risco para a saúde na Amadora utilizando técnicas de estatística espacial e multivariada que, dando a conhecer a geografia de algumas determinantes da saúde, poderão vir a constituir-se como auxiliares de intervenções estratégicas ao nível do planeamento urbano

    Multidisciplinary study of Santa Eulália Plutonic Complex (Central Portugal): Preliminary insight.

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    Multidisciplinary study of Santa Eulalia Plutonic Complex (Central Portugal): Preliminary insight H. SANT’OVAIA1*, J. CARRILHO LOPES2 AND P. NOGUEIRA2 1DGAOT, Centro de Geologia, FCUP, Portugal (*correspondence: [email protected]) 2Dep. Geo., Univ. Évora, Centro de Geologia UL, Portugal The Santa Eulália Plutonic Complex (SEPC) is a late- Variscan calcalkaline granitic body that occupies an area of 400 km2 and is located in the Variscan Iberian sector. The host rocks of the complex are composed by metamorphic formations from Proterozoic to Lower Paleozoic. The SEPC has two main facies which present different compositions and textures. From the rim to the core, there is a medium- to coarse-grained pinkish granite (G0) involving large masses of mafic to intermediate rocks and a central gray monzonitic granite (G1). The central facies can be divided into a porphyritic facies (G1A) and a central medium-grained facies (G1B). Multidisciplinary studies that include petrography, mineral and whole-rock chemistry, Anisotropy of Magnetic Susceptibility (AMS) and microstructural analyses were carried out. Besides petrographic and mineral chemistry data, whole-rock analytical results reveal clear differences between these two main granitic facies. G0 granites represent more evolved liquids (>SiO2 wt.% and <MgO wt.%), plot closer to metaluminous and A-type fields, and present negative Eu anomalies, while G1 facies are typically monzonitic granites with a strong peraluminous character. The AMS study was based on 50 sampling sites. The magnetic susceptibility ranges between 55.09 and 7343.67 x 10-6 SI. Two major groups can be established: facies G0, with Km > 10-3 SI which supports the presence of magnetite, and the central facies (G1A, G1B) with Km< 10-4 SI. In the central facies the paramagnetic behaviour is due to ferromagnesian minerals, such as biotite, and ilmenite. Magnetic anisotropy ranges between 2.2 and 18.2% being in mean >5% in facies G0 and <4% in the central facies. The high P% in G0 facies may be caused by the magnetic bearer, magnetite. Nevertheless, microscope observations show signs of a post-magmatic deformation in G0. These preliminary data support that the facies G0 and the central facies (G1) have a distinct magnetic behaviour which may suggest different redox conditions in magma genesis. This work has been financially supported by PTDC/CTEGIX/ 099447/2008 (FCT-Portugal, COMPETE/FEDER)

    SERS Research Applied to Polymer Based Nanocomposites

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    Polymer based nanocomposites containing metal nanoparticles (e.g. Au, Ag) have gained increased attention as a new class of SERS (Surface Enhanced Raman Scattering) substrates for analytical platforms. On the other hand, the application of SERS using such platforms can also provide new insights on the properties of composite materials. In this chapter, we review recent research on the development of SERS substrates based on polymer nanocomposites and their applications in different fields. The fundamentals of SERS are briefly approached and subsequently there is a reference to the strategies of preparation of polymer based nanocomposites. Here the main focus is on SERS studies that have used a diversity of polymer based nanocomposites, highlighting certain properties of the materials that are relevant for the envisaged functionalities. A final section is devoted to the joint use of Raman imaging and SERS in nanocomposites development, a topic that presents a great potential still to be explored as shown by the recent research in this field

    Pollination Services Provided by Melipona quadrifasciata Lepeletier (Hymenoptera: Meliponini) in Greenhouses with Solanum lycopersicum L. (Solanaceae)

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    Stingless bees are considered particularly promising for use as commercial pollinators, but studies testing the effectiveness of these bees in pollinating grape tomatoes in greenhouses have not yet been made. This study aimed to analyse the floral biology of the grape tomato and evaluate whether additional pollination performed by Melipona quadrifasciata Lepeletier, 1836 generates an effective increase in production and improves the quality of this variety of tomato when grown in greenhouses. The research was conducted in two greenhouses located in Araguari, Minas Gerais state, Brazil. In one, we only used a mechanical method of pollination and, in the other, pollination by the mechanical method was associated with pollination performed by the bees. The productivity of the greenhouses was compared by recording the number of flowers and fruits formed on different branches, and the quality of the tomatoes was assessed by analysing their size, weight, number of seeds and total sugar content. Tomatoes originating from flowers visited by M. quadrifasciata workers produced about 47% more seeds and their concentration of sugar was approximately 14% higher. These results suggest that using M. quadrifasciata for tomato pollination shows promise, since positive effects were generated on fruit quality

    MODELAÇÃO E INVERSÃO DE DADOS GRAVIMÉTRICOS. DETERMINAÇÃO NUMÉRICA COM APLICAÇÃO AO COMPLEXO PLUTÓNICO DE SANTA EULÁLIA

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    Os dados gravimétricos obtidos para o Complexo Plutónico de Santa Eulália - CPSE (Maximo, 2008; Sant'Ovaia et al., 2012) serviram de base para uma interpretação sobre a geologia 3D da região estudada. As densidades supostas das rochas são utilizadas para recalcular o campo gravítico à superfície, permitindo assim a consolidação da cartografia geológica proposta, a partir de um programa de cálculo numérico direto desenvolvido especificamente no âmbito de um projeto de investigação. Com base nos dados gravimétricos de campo é possível determinar, utilizando alguns pressupostos adicionais, o campo de densidades num volume englobando a área de estudo. Complementarmente está em desenvolvimento um outro programa numérico para efetuar esta inversão, com o objetivo de determinar as variações da densidade em profundidade a partir dos dados gravimétricos recolhidos no campo. Os resultados já obtidos com a utilização deste segundo programa (inversão) apontam para a existência de boa exatidão na determinação das densidades, a baixas profundidades (<3km). A maiores profundidades a incerteza dos valores da densidade aumenta. Em ambos os programas numéricos, a lei da gravitação universal é utilizada para relacionar densidades e acelerações gravíticas à superfície. O cálculo de g a partir de é efetuado de forma direta, admitindo valores médios regionais para e g conhecidos. Para a inversão são utilizados os mesmos princípios de base, aplicando-se o método de Monte Carlo para determinar os valores de que reproduzem as medidas de g. A abordagem apresentada tem como ponto de partida a distribuição de densidades em volumes de controlo. O domínio de cálculo é um paralelepípedo de 40x40x10 km, dividido em 4356 volumes de controlo com densidades uniformes. Os programas numéricos desenvolvidos utilizam a linguagem de programação Fortran. Na figura 1 são apresentados os resultados da inversão realizada para z = 0m, onde se pode observar que os resultados reproduzem de forma fiel a cartografia geológica da região, nomeadamente no que diz respeito às litologia aflorantes
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