994 resultados para Ce


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PARA ONDE SOPRAM OS VENTOS , metaphor used to indicate turism public politicsway to the west zone of Fortaleza, against the direction where until now this public politics was targeted, to the east zone. This context, análise the public politics implemented in the Grande Pirambu, so like the processes of nonterritorialization and reterritorialization unchain by the program os settlement and indemnification of the Projeto Costa Oeste. Aim to learn the transformations that unroll in the studied área, based in proceding methodologic that privileged the interviews with many social actors resettled, indemnificators, intirenants, livers and fishmen. The public politics analyzes run to the Grande Pirambu infer that the same answer at trying of urbam requalification of the área, object of the new exigence pretender by the touristics activities developed in Fortaleza, wish to incorporate this área at the turistics dynamic of the city. However, the implementation of the Projeto Costa Oeste do not occuring in calm way, by opposite sence the beginning, the same has been propitiated polemics and discussions, stired up about public politics between the municipa and state power, to bring about injury in the public coffers, to the developing turismo f the city and, mainly to the living around Grande Pirambu, unquiet and sad with the buildings of the referring project that there is running for four years

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The work present entitled the participation of resident in the production process of the tourist territory in Canoa Quebrada/CE has as objective analyse of which form the site population participates of the manufacturing process and appropriation of the territory s tourist Canoa Quebrada CE , in period undestood between from 1980 to the present day. The theoretical variable about which rest this search is the concept the territory expressed in the manifested in the process deterritorialization that always appears in conjuction whith the reconstruction of territories, in other words, the process of repossession. The migratory movement of new residents acts in the new sociospatial configuration that location, form new territoriality and (de) territorializing in space turistificado reflected dialectically through the emergence of a new sociospatial setting consisting of forms and images expressed physically in place.Finish the job showing that the participation of resident native and nonnative in the production process of the tourist territory in Canoa Quebrada occurred unevenly characterized by dominance of a small group, who has control of the practice of this activity, thus appears that tourism can be tendentious, since a large portion of the population does not benefit from their results, having a exclusion with various impacts that directly affect the everyday social population

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The Metropolitan Region of Fortaleza (RMF) is composed by thirteen cities, where is call the attention of Aquiraz. The city has a excellent resort area and a big importance in socioculture and historics aspects. It was one of the first village of Ceará, and it was founded in 1699, with was also the capital of the state until 1726. The urban local development has been disorganized in the last decades, the fact is, insert of turismon in its coast, and it is unable with alow capacity of the natural suppots, configuring unsustainable and et environment ambience. Considering as a turistic region, it is preoccupy, been necessart to create a better control of the nature of the region by the users. The environmental zoning in this work it is to plan of adequate form the use of the ground based in the management of the interests and the social and economic necessities in accord with the preservation of the environment and the natural characteristics of the city. The same is one great instrument planning where use to be analized in differents ways: social, ambiental, economical and institucional, and promove alternatives of use and occupation of the land to recreate the city. The methodo used to get the real objective, englobed zonal maps in ambiental unities and others themes (geologic/geomorphologic) since than the images from satelities LANDSAT and SPOT and fotografies under position of maps, secundaries listes gets in publics department, bibliographie, informations by the local populations. This prociduries mede easy to create maps, geologic/geomorphologic, of use and occupation the earth and the environmental zoning to analize the dynamic and the working of each ambiental unity of the city Aquiraz wich is located by map of this job. As a result of this job was confectionated the environmental zoning map of Aquiraz wich was divided in five ambiental unities and restrictions areas of occupation: unit I Littoral Plain (zoning with serious restrictions to the occupation); unit II Sub-Littoral Plain (improper zoning to the occupation); unit III between tray zoning Pré-Littoral and Peripheral Depression (improper zoning to the occupation); unit IV Strativism reserve of the plug (zoning used more under control in its occupation) and unit V Fluvial Plain Localities of the Indians Jenipapo-Kaninde/ locality Quilombolas (zoning used more without official regulation). With proposal in the ambient units above one expects that it has a reduction of the ambient degradation and protection of the local biodiversity of the city of Aquiraz in the State of the Ceará

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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In this work we propose the study of the spectroscopy properties and the energy level location of Ce(3+) and Pr(3+) in Gd(2)O(2)S, along with the effects of Ce(4+) (Ce(2)O(2)S(2)) incorporation in Gd(2)O(2)S and Gd(2)O(2)S: Pr(3+) in order to understand the formation and position of the associated defects energy levels in relation to the band structure of Gd(2)O(2)S and Pr(3+) energy levels. Ce-, Pr(3+)-doped and Pr(3+), Ce-doped Gd(2)O(2)S were prepared by the sulfidization of a basic gadolinium carbonate with S(8) using H(2)/N(2) (3.0/97.0%) and air during the firing of the precursor. Samples were analyzed by X-ray diffraction in order to guarantee the formation of the Gd(2)O(2)S single phase. Diffuse reflectance spectroscopy and luminescent measurements (emission/excitation) were used to locate Ce(3+), Pr(3+) and defects energy levels in relation to the band structure of Gd(2)O(2)S. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Ce-doped and undoped LiCaAlF6 (LiCAF) single crystals 50 mm in diameter were grown by the Czochralski technique. The formation of inclusions and cracks accompanying the crystal growth was investigated. The dependence of lattice parameters on the temperature was measured for LiCAF and LiSrAlF6 single crystals. Linear thermal expansion coefficients for both these crystals were evaluated. Higher transmission properties for LiCAF single crystals were achieved in the UV and VUV wavelength regions. (C) 2001 Elsevier B.V. B.V. All rights reserved.

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In this work, a CE method for the determination of olive oil acidity was proposed. The method was based on an ethanolic extraction (at 60 degrees C) of the oil long-chain free fatty acids (LC-FFAs) components followed by CE determination in pH 6.86 phosphate buffer at 15 mmol/L concentration containing 4 mmol/L sodium dodecylbenzenesulfonate (SDBS), 10 mmol/L polyoxyethylene 23 lauryl ether (Brij 35((R))), 2% v/v 1-octanol and 45% v/v ACN under indirect UV detection at 224 nm. Although this electrolyte promoted baseline separation of myristic acid (C14:0) (internal standard (IS)) and olive oil major components (palmitic acid (C16:0), oleic acid (C18:1c) and linoleic acid (C18:2cc)) in less than 8 min, after a few injections, the electropherogram profiles were severely altered (peak broadening, migration time shifts, etc.) and the current increased substantially. An adsorption study was conducted revealing that the dissolution of the capillary external polyimide coating during the electrophoretic run caused the detrimental effect. After removal of the capillary tip coating, ten consecutive injections could be performed without any disturbances and this simple procedure was, therefore, implemented during quantitative purposes. The reliability of the proposed method was further investigated by the determination of acidity of an extra virgin olive oil sample in comparison to the established methodology (AOCS method Ca 5a40, alkaline volumetric titration (AVT)). No statistical differences were found within 95% confidence level. A % acidity of 0.39 +/- 0.02 was found for the olive oil sample under consideration.

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Anomalous thermal behavior on the EPR linewidths of Gd impurities diluted in Cc compounds has been observed. In metals, the local magnetic moment EPR linewidth, Delta H, is expected to increase linearly with the temperature. In contrast, in CexLa1-xOs2 the Gd EPR spectra show a nonlinear increase. In this work, the mechanisms that are responsible for the thermal behavior of the EPR lines in CexLa1-xOs2 are examined. We show that the exchange interaction between the local magnetic moments and the conduction electrons are responsible for the narrowing of the spectra at low temperatures. At high temperatures, the contribution to the linewidth of the exchange interaction between the local magnetic moments and the Ce ions has an exponential dependence on the excitation energy of the intermediate valent ions. A complete fitting of the EPR spectra for powdered samples is obtained, (C) 1998 American Institute of Physics. [S0021-8979(98)39911-9].

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Structural morphological studies in pure and Ce-doped tin dioxide nanoparticles with high stability against particle growth were performed in samples, obtained using the polymeric precursor method and prepared at different annealing temperatures. A Ce-rich surface layer was used to control the particle size and stabilize SnO2 against particle growth. The formation of this segregated layer can contribute to a decreased surface energy, acting in the driving force, or reducing the surface mobility. Only the cassiterite SnO2 phase was observed below 1000 degreesC and a secondary phase (CeO2) was observed for the Ce-doped SnO2 at temperatures higher than 1000 degreesC, when de-mixing process occurs. The evolution of crystallite size, microstrain and morphology of the nanoparticles with annealing temperatures was investigated by X-ray diffraction (XRD), associated to Rietveld refinements, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). (C) 2002 Elsevier B.V. Ltd. All rights reserved.

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In this work particles of ZnO of size range 33-56 Angstrom were prepared by a sol-gel method. The effect of reaction time on the particle size of ZnO or ZnO:Ce was investigated by transmission electron microscopy measurements, UV-vis absorption and luminescence spectroscopy. A linear increase of the mean particle size is observed as a function of reaction time. The cerium-doped particles are bigger than the pure ZnO ones obtained at the same reaction time. A shift to lower energy at the maximum of the bands is observed in all absorption, emission and excitation spectra as a function of particle growth. From the absorption spectra the optical energy gap values (Eg) for these particles were determined. In the quantum size regime, Eg was found to decrease with particle growth.

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Anomalous thermal behavior on the EPR linewidths has been observed for Gd impurities diluted in CexA1-xBn (A=La,Y, B=Ir,Os,Rh,Pd) intermediate-valence compounds. In this work we show that the exchange interaction between the local magnetic moments and the intermediate-valence host ions has an important contribution to the relaxation rates of the local moments. We calculated the relaxation, using the Redfield formalism and the ideas contained in the interconfigurational fluctuation model of Hirst. We show that the exchange interaction contribution has an exponential dependence on the excitation energy of the intermediate-valence ions. © 1992 The American Physical Society.

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The CO2 reforming of CH4 was carried out over Ni catalysts supported on γ-Al2O3 and CeO 2-promoted γ-Al2O3. The catalysts were characterized by means of surface area measurements, TPR, CO2 and H2 chemisorption, XRD, SEM, and TEM. The CeO2 addition promoted an increase of catalytic activity and stability. The improvement in the resistance to carbon deposition is attributed to the highest CO2 adsorption presented by the CeO2 addition. The catalytic behavior presented by the samples, with a different CH4/CO2 ratio used, points to the CH4 decomposition reaction as the main source of carbon deposition.

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Optical excitation of Ce3+-doped SnO2 thin films, obtained by the sol-gel-dip-coating technique, is carried out and the effects on electrical transport are evaluated. Samples are doped with O. lat% of Ce, just above the saturation limit. The excitation is done with an intensity-controlled halogen-tungsten lamp through an interference filter, yielding an excitation wavelength of 513nm, 9 nm wide (width at half intensity peak). Irradiation at low temperature (25K) yields a conductivity increase much lower than above bandgap light. Such a behavior assures the ionization of intra-bandgap defect levels, since the filter does not allow excitation of electron-hole pairs, what would happen only in the UV range (below about 350nm). The decay of intra-bandgap excited levels in the range 250-320 K is recorded, leading to a temperature dependent behavior related to a thermally excited capture cross section for the dominating defect level. © 2008 American Institute of Physics.