991 resultados para RAIOS CÓSMICOS
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This thesis focuses on the coprecipitation synthesis method for preparation of ceramic materials with perovskite structure, their characterization and application as catalytic material in the reaction of converting CO to CO2 developing a methodological alternative route of synthesis from the middle via oxalate coprecipitation material SrCo0,8Fe0,2O3-d. In order to check the influence of this method, it was also synthesized using a combined citrate - EDTA complexing method. The material was characterized by: X-ray diffraction (XRD), Rietveld refinement method, thermogravimetry and differential thermo analysis (TG / DTA), scanning (SEM) and transmission (TEM) electron microscopy, particle size distribution and surface analysis method BET. Both methods led to post-phase synthesis, with pH as a relevant parameter. The synthesis based on the method via oxalate coprecipitation among particles led to the crystalline phase as those obtained using a combined citrate - EDTA complexing method under the same conditions of heat treatment. The nature of the reagent used via oxalate coprecipitation method produced a material with approximately 80 % lower than the average size of crystallites. Moreover, the via oxalate coprecipitation method precursors obtained in the solid state at low temperature (~ 26 oC), shorter synthesis, greater thermal stability and a higher yield of around 90-95 %, maintaining the same order of magnitude the crystallite size that the combined citrate - EDTA complexing method. For purposes of comparing the catalytic properties of the material was also synthesized by the using a combined citrate - EDTA complexing method. The evaluation of catalytic materials SrCo0,8Fe0,2O3-d LaNi0,3Co0,7O3-d was accompanied on the oxidation of CO to CO2 using a stainless steel tubular reactor in the temperature range of 75-300 oC. The conversion CO gas was evaluated in both materials on the results shaved that the firm conversion was loves for the material LaNi0,3Co0,7O3-d
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A incidência do carcinoma basocelular vem aumentando em todos os países. Realizou-se estudo ecológico de 5169 laudos de carcinoma basocelular, da FMB-Unesp, entre janeiro/1999 e dezembro/2009. O incremento médio da incidência para o período foi de 90,6%, projetando-se um diagnóstico para cada 15 pacientes encaminhados à dermatologia. Tal tendência se manteve, mesmo quando indexada pelo número de laudos histopatológicos, movimento hospitalar, atendimentos da dermatologia e população de Botucatu.
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Queratoses actínicas são neoplasias benignas intraepiteliais formadas por proliferações atípicas de queratinócitos com potencial de transformação em carcinoma espinocelular. Desenvolvem-se em áreas fotoexpostas da pele, são induzidas principalmente pela radiação ultravioleta e constituem marcadores de exposição solar crônica. Acometem indivíduos adultos e idosos, de fototipos claros, representando o quarto diagnóstico dermatológico mais comum no Brasil. Danos nas vias de apoptose do epitélio fotoexposto favorecem a proliferação celular e manutenção das lesões. Nesta revisão os autores reúnem os principais dados epidemiológicos sobre a doença e defendem que estratégias de identificação de fenótipos de risco, diagnóstico precoce, tratamento adequado, seguimento clínico, incentivo ao autoexame da pele, fotoeducação e fotoproteção devem ser promovidas, a fim de evitar a evolução das lesões, e também prevenir e diagnosticar neoplasias concomitantes também induzidas pela radiação solar.
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The calcium ferrite (Ca2Fe2O5) has a perovskite-type structure with oxygen deficiency and is used as a chemical catalyst. With the advent of nanoscience and nanotechnology, methods of preparation, physical and chemical characterizations, and the technological applications of nanoparticles have attracted great scientific interest. Calcium nanostructured ferrites were produced via high-energy milling, with subsequent heat treatment. The milling products were characterized by X-ray diffraction, magnetization and Mössbauer spectroscopy. Samples of the type Ca2Fe2O5 were obtained from the CaCO3 and Fe2O3 powder precursors, which were mixed stoichiometrically and milled for 10h and thermally treated at 700ºC, 900ºC and 1100ºC. The Mössbauer spectra of the treated samples were adjusted three subespectros: calcium ferrite (octahedral and tetrahedral sites) and a paramagnetic component, related to very small particles of calcium ferrite, which are in a superparamagnetic state. For samples beats in an atmosphere of methyl alcohol, there is a significant increase in area associated with the paramagnetic component. Hysteresis curves obtained are characteristic of a weak ferromagnetic-like material
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Samples of lanthanum Ortoferrites doped with strontium were synthesized in a single phase by the sol-gel method. Two samples were prepared, one by varying the concentration of strontium in lanthanum ortoferrites La1−xSrxFeO3−δ with (0 ≤ x ≤ 0.5), and another batch of samples of type, La1/3Sr2/3FeO3−δ, now varying only the temperature of calcination. Our samples were obtained by Pechini method and sintered in air and oxygen atmospheric. Their crystal structures were determined by x-ray diraction (XRD), scanning electron microscopy (SEM), where we observed that the samples (0 ≤ x ≤ 0.3) have orthorhombic symmetry and the volume of the single cell decreases with the increasing of concentration of strontium. For x = 0.5 it is only observed the simple phase when that is sintered in O2 atmospheric. Their magnetic characteristics were obtained by the Mössbauer spectroscopy and magnetic measurements. The magnetization measurements for samples La1−xSrxFeO3−δ with (0 ≤ x ≤ 0.5) revealed that the magnetization decreases with increasing concentration of strontium, but for the sample x = 0.4 the magnetization shows a high coercive field and a ferrimagnetic behavior, which is attributed to a small amount of strontium hexaferrite. As for the samples La1/3Sr2/3FeO3−δ calcined between 800 oC e 1200 oC. The hysteresis curves revealed two distinct behaviors: an declined antiferromagnetic behavior (Canted) for samples calcined between 800 oC and 1000 oC and a paramagnetic behavior for the samples calcined at 1100 oC e 1200 o C. Thermal hysteresis and sharp peaks around the Néel temperature (TN), over the curves of specific heat as a function of temperature was only observed in calcined samples with 1100 oC and 1200 oC. This eect is attributed to the charge ordering. These results indicate that the charge ordering occurs only in the samples without oxygen deficiency. Magnetic measurements as a function of temperature are also in agreement with this interpretation
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In this work we have developed a way to grow Fe/MgO(100) monocrystals by magnetron sputtering DC. We investigated the growing in a temperature range among 100 oC and 300 oC. Structural and magneto-crystalline properties were studied by different experimental techniques. Thickness and surface roughness of the films were investigated by atomic force microscopy, while magneto-crystalline properties were investigated by magneto-optical Kerr effect and ferromagnetic resonance. Our results show that as we increase the deposition temperature, the magneto-crystalline anisotropy of the films also increases, following the equation of Avrami. The best temperature value to make a film is 300 oC. As the main result, we built a base of magnetoresistence devices and as an aplication, we present measurements of Fe/Cr/Fe trilayer coupling. In a second work we investigated the temperature dependence of the first three interlayer spacings of Ag(100) surface using low energy electron diffraction. A linear expansion model of crystal surface was used and the values of Debye temperatures of the first two layers and thermal expansion coefficient were determinated. A relaxation of 1% was found for Ag(100) surface and these results are matched with faces (110) and (111) of the silver. iv
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
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OBJETIVO: Avaliar a prevalência de lesões cutâneas actínicas em portadores de carcinoma basocelular do segmento cefálico. MÉTODOS: Foi conduzido estudo tipo caso-controle. Os casos, constituídos por pacientes com carcinoma basocelular sólido, primário, menor que dois centímetros, no segmento cefálico; e controles, por pacientes com outras dermatoses. Foram analisadas variáveis constitucionais, comportamentais e lesões actínicas. RESULTADOS: Avaliaram-se 120 casos e 360 controles. Mílio facial (OR = 2,3), leucodermia puntacta de membros superiores (OR = 2,9) e cutis romboidalis nuchae (OR = 1,8) associaram-se à neoplasia independentemente das demais variáveis, sugerindo um fenótipo de risco. Houve ainda associação com fenótipos claros, genética familiar e exposição solar cumulativa. Queimadura solar, tabagismo e alcoolismo não foram identificados como fatores de risco. O uso de fotoprotetores não evidenciou proteção; porém, o grupo controle era composto por pacientes dermatológicos, aos quais são indicados fotoprotetores regularmente. CONCLUSÃO: Lesões actínicas foram mais prevalentes em portadores de carcinoma basocelular sólido do segmento cefálico que em controles, especialmente mílio, cutis romboidalis nuchae e leucodermia puntacta, independentemente dos demais fatores de risco conhecidos.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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In this work we obtain nickel ferrite by the combustion synthesis method whcih involves synthesising in an oven at temperatures of 750oC, 950oC and 125oC. The precursors oxidizing used were nickel nitrate, ferric as an oxidizing and reducing urea (fuel). After obtaining the mixture, the product was deagglomerated and past through a 270 mesh sieve. To assess the structure, morphology, particle size, magnetic and electrical properties of nanoparticles obtained the samples were sintered and characterized by x-ray distraction (XRD), x-ray fluorescence spectroscopy (FRX); scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), vibrating sample magnetometer (MAV ) and electrical permittivity. The results indicated the majority of phase inverse spinel ferrite and Hematite secondary phase nickel and nickel oxide. Through the intensity of the distraction, the average size of the crystallization peaks were half-height width which was calculated using the Scherrer equation. From observing the peaks of all the reflections, it appears that samples are crystal clear with the formation of nanoparticles. Morphologically, the nanoferritas sintered nickel pellet formation was observed with three systems of particle size below 100mn, which favored the formation of soft pellets. The average size of the grains in their micrometric scale. FRX and EDS showed qualitatively the presence of iron elements nickel and oxygen, where through quantitative data we can observe the presence of the secondary phase. The magnetic properties and the saturation magnetization and the coercive field are in accordance with the nickel, ferrite where the curve of hysteresis has aspects of a soft material. Dielectric constant values are below 10 and low tangent loss
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This dissertation presents a study on crustal seismic anisotropy in Cascavel - CE. The earthquake data employed here are from the Seismological Laboratory at Universidade Federal do Rio Grande do Norte (UFRN) and were colected from 29 September 1997 to 05 march 1998 using six three-component digital seismographic stations. In general, the cause of the observed seismic anisotropy in many regions of the world is interpreted in terms of fluid-filled stress aligned microcracks in the rockmass (EDA). In other words, the polarisation direction of the faster shear-wave splitting is parallel to SHmax. However, other researches on seismic anisotropy carried out in NE Brazil have shown a remarkable consistency of the faster shear-wave polarisation direction with the direction of the Precambrian fabric. The present work is another case study that is used to investigate this issue. In order to map the Precambrian fabric we used aeromagnetic data, since the study area is mostly covered with sediments (up to 50m thick) and in-situ field mapping would be very difficult to be carried out. According to the results from the present research, the observations of the faster shear-wave polarisation directions in two seismographic stations in Cascavel region are best explained in the framework of EDA. For the remaining two stations, the observed anisotropy may have two interpretions: (i) - 90_ flips of the direction of polarisation of the faster shear-wave, since that the event-to-station ray path would be through the fracture zone and hence would travel under a higher pore pressure and (ii) - the observed seismic anisotropy would agree with the direction on the ductile Precambrian fabric
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This study focuses on the potential of several techniques used to identify depositional geometries and paleogeographical investigation on the SW border of the Potiguar Basin. Three areas were selected for an integrated geological, geophysical and geochemistry study. The main used techniques were facies analysis, remote sensing,ground penetrating radar (GPR) and gamma-ray in outcrops, as well as petrographic microscope observations and the using of scanning eletronic microscopic (SEM), and Carbon and Oxygen Isotopic study in the carbonate tufa. These methodological approaches were very efficient in the facies analysis of 2D geometries. The GPR profiles carried out in Quixeré identified important geological reflectors which allowed to the identification of depositional geometries of tufa. However, GPR profiles were not able to identify geological reflectors in the Apodi and Olho d´Água da Bica outcrops. Gammaray profiles also presented good results, which justify their use in 1D and 2D geometric analysis. Carbon and Oxygen Isotopic analyses were also used to investigate paleoenvironmental setting of tufa deposits. It is important to remark the excellent resultsof GRP using in the identification of deposition al geometries of tufa and their contact relationships with the underlying rocks. Field analysis of faults indicate a vertical sigma-1 orientation which was associated to normal faults
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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In this paper we present the methodological procedures involved in the digital imaging in mesoscale of a block of travertines rock of quaternary age, originating from the city of Acquasanta, located in the Apennines, Italy. This rocky block, called T-Block, was stored in the courtyard of the Laboratório Experimental Petróleo "Kelsen Valente" (LabPetro), of Universidade Estadual de Campinas (UNICAMP), so that from it were performed Scientific studies, mainly for research groups universities and research centers working in brazilian areas of reservoir characterization and 3D digital imaging. The purpose of this work is the development of a Model Solid Digital, from the use of non-invasive techniques of digital 3D imaging of internal and external surfaces of the T-Block. For the imaging of the external surfaces technology has been used LIDAR (Light Detection and Range) and the imaging surface Interior was done using Ground Penetrating Radar (GPR), moreover, profiles were obtained with a Gamma Ray Gamae-spectômetro laptop. The goal of 3D digital imaging involved the identification and parameterization of surface geological and sedimentary facies that could represent heterogeneities depositional mesoscale, based on study of a block rocky with dimensions of approximately 1.60 m x 1.60 m x 2.70 m. The data acquired by means of terrestrial laser scanner made available georeferenced spatial information of the surface of the block (X, Y, Z), and varying the intensity values of the return laser beam and high resolution RGB data (3 mm x 3 mm), total points acquired 28,505,106. This information was used as an aid in the interpretation of radargrams and are ready to be displayed in rooms virtual reality. With the GPR was obtained 15 profiles of 2.3 m and 2 3D grids, each with 24 sections horizontal of 1.3 and 14 m vertical sections of 2.3 m, both the Antenna 900 MHz to about 2600 MHz antenna. Finally, the use of GPR associated with Laser Scanner enabled the identification and 3D mapping of 3 different radarfácies which were correlated with three sedimentary facies as had been defined at the outset. The 6 profiles showed gamma a low amplitude variation in the values of radioactivity. This is likely due to the fact of the sedimentary layers profiled have the same mineralogical composition, being composed by carbonate sediments, with no clay in siliciclastic pellitic layers or other mineral carrier elements radioactive
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OBJETIVO: Avaliar o volume orbitário de coelhos recém-nascidos, enucleados ou eviscerados, sem ou com reposição do volume orbitário por esferas de polietileno poroso de 10 mm, usando a tomografia computadorizada, o teste de deslocamento de água e a medida da abertura orbitária por Image-J. MÉTODOS: Estudo experimental, usando 48 coelhos albinos, com idade de 42 dias, submetidos à evisceração ou enucleação, com implante de esfera de polietileno poroso de 10 mm de diâmetro ou sem implante. O lado esquerdo não foi submetido à cirurgia e foi usado como controle. Após 1, 3 e 6 meses, foram sacrificados quatro animais de cada grupo. Os crânios foram preparados para estudo do osso seco por maceração da peça, e analisados em relação ao volume orbitário por tomografia computadorizada, teste de deslocamento de água e avaliação da abertura orbitária usando o software Image-J. RESULTADOS: O volume das órbitas enucleadas ou evisceradas, com ou sem o uso do implante não apresentaram diferenças estatisticamente significativas (p<0,05) entre si, quando avaliadas por tomografia computadorizada, pelo teste de deslocamento de água e pelo Image-J. CONCLUSÃO: O desenvolvimento orbitário de coelhos com idade superior a 42 dias de vida não se altera quando se opta pela enucleação ou pela evisceração, ou quando se utiliza ou não implantes orbitários. O teste de deslocamento de água apresentou resultados semelhantes aos fornecidos pela tomografia, sugerindo-se sua utilização em experimentação científica.