560 resultados para Mor


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The effect of several desilication experimental parameters (base concentration, temperature and time) on the characteristics of MOR zeolite was studied. The samples were characterized by X-ray diffraction, Al-27 and Si-29 MAS-NMR, chemical analysis, and FTIR (framework vibration region). The textural characterization was made by N-2 adsorption and the acidity was evaluated by pyridine adsorption followed by FTIR and by the catalytic model reaction of n-heptane cracking. The alkaline treatments promoted the Si extraction from the zeolite framework, without considerable loss of crystallinity and, as it was envisaged, an important increase of the mesoporous structure was attained. A linear correlation between the number of framework Si per unit cell. N-Si and the asymmetric stretching wavenumber, nu(i), was observed. The acidity characterization shows that the desilicated samples exhibit practically the same acid properties than the parent HMOR zeolite. The optimum desilication conditions were those used to obtain sample M/0.2/85/2, i.e., sample treated with 0.2 M NaOH solution at 85 degrees C for 2 h.

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MOR zeolites were modified via desilication treatments with NaOH, under conventional and microwave heating. The samples were characterized by powder X-ray diffraction, (27)Al and (29)Si NMR spectroscopy. TEM and N(2) adsorption at -196 degrees C. The acidity of the samples and the space available inside the pores were evaluated through a catalytic model reaction, the isomerization of m-xylene, for which the profiles of the coke thermal decomposition were also analyzed. Powder X-ray diffraction and (29)Si and (27)Al MNR results show that in comparison with conventional heating, microwave irradiation (a less time consuming process) leads to identical amount of Si extraction from the zeolite framework. With this treatment. in addition to the customary mesopores development promoted by conventional heating, a partial conversion of the zeolite microporosity into larger micropores, is observed. The microwave irradiated and conventionally heated samples show different catalytic behavior in the m-xylene isomerization model reaction. It was observed that, by controlling the experimental conditions, it is possible to obtain samples with catalytic properties closer to the parent material, which is also confirmed by the respective coke analysis. (C) 2011 Elsevier B.V. All rights reserved.

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The hydrotris(pyrazol-1-yl)methane iron(II) complex [FeCl2{eta(3)-HC(pz)(3)}] (Fe, pz = pyrazol-1-yl) immobilized on commercial (MOR) or desilicated (MOR-D) zeolite, catalyses the oxidation of cyclohexane with hydrogen peroxide to cyclohexanol and cyclohexanone, under mild conditions. MOR-D/Fe (desilicated zeolite supported [FeCl2{eta(3)-HC(pz)(3)}] complex) provides an outstanding catalytic activity (TON up to 2.90 x 10(3)) with the concomitant overall yield of 38%, and can be easy recovered and reused. The MOR or MOR-D supported hydrotris(pyrazol-1-yl)methane iron(II) complex (MOR/Fe and MOR-D/Fe, respectively) was characterized by X-ray powder diffraction, ICP-AES, and TEM studies as well as by IR spectroscopy and N-2 adsorption at -196 degrees C. The catalytic operational conditions (e.g., reaction time, type and amount of oxidant, presence of acid and type of solvent) were optimized. (C) 2013 Elsevier B.V. All rights reserved.

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L'1 de setembre va morir a Barcelona el primer catedràtic de genètica de l'estat, el professor Antoni Prevosti i Pelegrín.

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[spa]El presente trabajo culmina un proyecto dedicado al estudio de cuatro láminas de plomo con escritura ibérica procedentes del área ilergeta, que habñian sido extraídas de forma irregular de forma irregular a principios de la década de los años 80 del pasado siglo y que acabaron en el Instituto de Estudios Ilerdenses. En 2005 se dio a conocer el plomo de Olriols (Sant Esteve de Llitera), en 2009 los plomos 1 y 2 de Monteró (Camarasa) y ahora finalmente el plomo del Tossal del Mor (Tárrega). Este texto es muy corto, sólo consta de cuatro segmentos, todos posiblemete antropónimos sin ningún morfo añadido. Desde el punto de vista paleográfico, es significativo que por primera vez se documente un signo dual ko complejo en la zona ilergeta. Mientras que del léxico, cabe destacar que en uno de los antroponimos se documenta por primera vez con claridad en una inscripción ibérica el elemento iber. Independientemente de su significado parece plausible su relación con el etnónimo o con el río con los que antiguos griegos y romanos identificaban a los íberos. [eng]This work is the culmination of a project dedicated to the study of four sheets of lead with Iberian writing from the Ilerget area that had been extracted without authorisation in the early 1980s and that found way to the Institut d"Estudis Ilerdencs (Lleida). In 2005, the lead from Olriols (Sant Esteve de Llitera) was presented, as were lead sheets 1 and 2 from Monteró (Camarasa) in 2009 and now finally the lad piece from Tossal del Mor (Tàrrega). The text is very short, with only four segments, all possibly anthroponyms without any added morph. From the palaeographic point of view, it is significant that, for the first time, a complex dual ko sign is documented in the Ilerget area. Regarding the lexis, it is of note that in one of the anthroponyms the element ibeŕ is documented clearly for the first time in an Iberian inscription. Independently of its meaning, it seems plausible to link it to the ethnonym or the river with which the ancient Greeks and Romans identified the Iberians.

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kuv., 14 x 22 cm

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The study area of the Guarda-Mor target (Israelândia-GO) contextualizes the terrains of the estaern portion of the Arenópolis Magmatic Arc, more accurately, the Neoproterozoic associations inserted in the field of the Jaupaci volcano-sedimentary sequence. The mapped area is located in the central-western of Goiás state. The presente paper has as main objective to characterize the structural, petrographic and litogeochemistry of the target rocks beyond to compare these factors with the Mina Bacilândia rocks (Fazenda Nova-GO) in order to assess the genetic similarity of volcano-sedimentary units and deposits associated. The Guarda-Mor target is represented by the Jaupaci metavolcanic rocks sequence presenting bimodal volcanism. This sequence consists in metafelsic rocks like sericite/muscovite quartz schist, phyllite and metarriolites and/or metariodacites with calc-alkaline geochemical signature and metamafic rocks with tholeiitic character formed by actinolite - chlorite schist and chlorite - quartz schist. Besides the package of supracrustal rocks also can be observed the occurrence of a local intrusion syn- to late - tectonic named Granito Subvulcânico. In the study area beyond the marked volcanism also seen an event of crustal melting granitogênese evidenced by the presence of 2 granites at the east and the west of the map, Granito Israelândia and Granito Iporá respectively. Structural analysis both at the macro and micro have identified 3 deformation phases. The types of rock on the region record features in the metamorphic facies top and down. These features were subdivided into 3 metamorphic areas: the east and West areas show thermal metamorphism due to intrusion of adjacente granites while the central domain displays features of regional metamorphism. Gold mineralization of the Guarda –Mor deposit target suggests a possible structural control beyond pronounced the hydrothermal alteration. The mineralization may also be...