• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 70
  • 61
  • 30
  • 12
  • 7
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 280
  • 68
  • 52
  • 48
  • 46
  • 43
  • 40
  • 35
  • 29
  • 29
  • 26
  • 26
  • 26
  • 22
  • 21
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Granito Taquaral : evidências de um arco magmático orosiriano no sul do Cráton Amazônico na região de Corumbá - MS

Redes, Letícia Alexandre 13 February 2015 (has links)
Submitted by Jordan (jordanbiblio@gmail.com) on 2016-10-21T11:39:58Z No. of bitstreams: 1 DISS_2015_Leticia Alexandre Redes.pdf: 8294298 bytes, checksum: 8db7bb3276d8fbf7eb60e5f07cf9aec7 (MD5) / Approved for entry into archive by Jordan (jordanbiblio@gmail.com) on 2016-10-21T11:40:54Z (GMT) No. of bitstreams: 1 DISS_2015_Leticia Alexandre Redes.pdf: 8294298 bytes, checksum: 8db7bb3276d8fbf7eb60e5f07cf9aec7 (MD5) / Made available in DSpace on 2016-10-21T11:40:54Z (GMT). No. of bitstreams: 1 DISS_2015_Leticia Alexandre Redes.pdf: 8294298 bytes, checksum: 8db7bb3276d8fbf7eb60e5f07cf9aec7 (MD5) Previous issue date: 2015-02-13 / CAPES / O Granito Taquaral possui dimensões batolíticas, localiza-se no sul do Cráton Amazônico, na região de Corumbá, extremo ocidente do estado de Mato Grosso do Sul, próximo ao limite Brasil-Bolívia, sendo parcialmente recoberto pelas rochas sedimentares das formações Urucum, Tamengo, Bocaina e Pantanal e pelas as Aluviões Atuais. Com base no estudo das rochas do Granito Taquaral a partir de granulação, cor e composição, juntamente com o mapeamento geológico de detalhe, foi realizada a identificação de três fácies petrográficas: Fácies Média a Grossa Cinza, Fácies Grossa Rosa e Fácies Fina Rosa. A primeira é, volumetricamente, dominante no corpo mapeado; caracteriza-se por rochas leucocráticas, de cor cinza, textura inequi a equigranular média a grossa, às vezes, mostra-se milonitizada e são classificadas como quartzo-monzodiorito, granodiorito e monzogranito. A segunda é constituída por rochas leucocráticas de cor rosa, inequigranulares, grossas, de composição quartzo-monzonito e monzogranito. Enquanto que a terceira é composta por rochas hololeucocráticas de cor rosa-claro, equi a inequigranulares classificadas como monzo a sienogranítica, de granulação fina e representadas por diques aplíticos. Localmente são encontrados dois tipos de enclaves de natureza e origens diferentes, um de composição máfica, corresponde a xenólito e outro, identificado como Enclave Microgranular Félsico. Na área de estudo são encontrados, também diques de diabásio sempre em contatos abruptos com o granito. Foram identificadas duas fases deformacionais, uma de natureza dúctil (F1) e outra rúptil/rúptil-dúctil (F2). Os dados geoquímicos indicam composição intermediária a ácida para essas rochas e sugerem sua colocação em ambiente de arco, representando um magmatismo cálcio-alcalino de médio a alto-K, metaluminoso a peraluminoso. Através do método geocronológico U-Pb (SHRIMP) em zircão se obteve idade de 1861±5,3 Ma para sua cristalização. Análises Sm-Nd em rocha total fornecem valores de εNd(1,86 Ga) de -1,48 e -1,28 e TDM de 2,32 e 2,25 Ga apontando para uma provável fonte crustal riaciana. Os resultados obtidos apontam que o Granito Taquaral corresponde a um magmatismo desenvolvido no final do Orosiriano no Arco Magmático Amoguijá. / The Taquaral Granite comprises an intrusion of batholithic dimensions, located in the south of the Amazon Craton in Corumbá region - far west of the state of Mato Grosso do Sul, near the border between Brazil and Bolivia -, partially covered by sedimentary rocks of the Urucum, Tamengo, Bocaina and Pantanal formations and the Alluvial Deposits. Based on grain size, color, and composition along with detailed geological mapping, three petrographic facies are attributed to the rocks of Taquaral Granite: Medium to Coarse-grained Grey Facies, Coarse-grained Pink Facies and Fine-grained Pink Facies. The first facies is volumetrically dominant in the mapped body; characterized by leucocratic rocks, grey, inequigranular to equigranular medium-to-coarse grained, sometimes displaying a mylonitized texture and are classified as quartz-monzodiorite, granodiorite and monzogranite. The second facies consists of pink leucocratic rocks, inequigranular, coarse-grained, of quartz monzonite and monzogranite composition. In turn, the third facies consists of light-pink hololeucocratic rocks, equigranular to inequigranular, classified as fine-grained aplite dykes of monzogranitic to syenogranitic composition. Two different types of enclaves are locally found: one corresponds to a mafic xenolith; another is identified as felsic microgranular enclave. In the study area, diabase dikes are also found, always in direct contact with the granite. Two deformation phases are identified, one of ductile behaviour (F1) and another of brittle / ductile brittle behaviour (F2). Geochemical data indicate intermediate to acid composition for these rocks and suggest an arc environment, representing a medium to high-K calc-alkaline magmatism, metaluminous to peraluminous. SHRIMP U-Pb zircon ages of 1861 ± 5.3 Ma are attributed to crystallization. Sm-Nd whole rock analyses provided negative εNd(1.86 Ga) values (-1.48 and -1.28) and TDM model ages from 2.32 to 2.25 Ga indicating a Rhyacian crustal source. The results indicate that Taquaral Granite is an evidence of a magmatism developed in the Amoguijá Magmatic Arc in late Orosirian.
112

Magmatismo cálcio - alcalino calimiano no embasamento do terreno Jauru (Província Rondoniana San Ignácio), Craton Amazônico : geoquímica e geocronologia Sm-Nd e U-Pb

Fachetti, Frankie James Serrano 01 July 2015 (has links)
Submitted by Jordan (jordanbiblio@gmail.com) on 2016-11-03T14:43:40Z No. of bitstreams: 1 DISS_2015_Frankie James Serrano Fachetti.pdf: 2106239 bytes, checksum: 3e47ff5badd6589019a10893b630751b (MD5) / Approved for entry into archive by Jordan (jordanbiblio@gmail.com) on 2016-12-15T15:37:50Z (GMT) No. of bitstreams: 1 DISS_2015_Frankie James Serrano Fachetti.pdf: 2106239 bytes, checksum: 3e47ff5badd6589019a10893b630751b (MD5) / Made available in DSpace on 2016-12-15T15:37:51Z (GMT). No. of bitstreams: 1 DISS_2015_Frankie James Serrano Fachetti.pdf: 2106239 bytes, checksum: 3e47ff5badd6589019a10893b630751b (MD5) Previous issue date: 2015-07-01 / CAPES / O Ortognaisse Taquarussu e o Granodiorito Guadalupe, integrantes do embasamento da Província Rondoniana - San Ignácio, SW do Cráton Amazônico, norte do município de Jauru- MT, correspondem a corpos orientados segundo um trend principal NW/SE. São rochas de composição granodiorítica com ocorrências subordinadas de monzogranitos. Na petrografia, são rochas de granulação fina a grossa, constituídas essencialmente por plagioclásio, quartzo, microclina, ortoclásio e biotita. Os minerais acessórios são: anfibólio, titanita, granada, apatita, epidoto, zircão e opacos. Apresentam evidências de pelo menos três fases de deformação dúcteis onde a principal estrutura relacionada a fase D1 é a foliação S1, representada ora por um bandamento composicional, ora por uma xistosidade. A segunda fase corresponde a uma clivagem de crenulação que transpõe a foliação S1, A terceira fase é exemplificada pela implantação de zonas de cisalhamento que geraram uma foliação/faturamento de escala local. O estudo geoquímico permitiu classificar as rochas como granodioritos e monzogranitos, oriundos de um magmatismo intermediário a ácido, de caráter sub-alcalino, da série cálcio-alcalina a cálcio-alcalina alto K, com índices de alumina que varia de metaluminoso a levemente peraluminoso. Foram classificados como gerados em ambiente de arco de ilhas e os dados U-Pb (Shrimp em zircão) mostram uma idade concórdia de 1575±6Ma. A idade modelo das análises de Sm-Nd (TDM) apontam para 1,63Ga, com εNd (t=1,57Ga) variando entre -1,52 e +0,78. Estes dados permitem caracterizar estas rochas como uma crosta juvenil com uma possível contaminação de rochas crustais. / The Taquarussu orthogneiss and the Guadalupe Granodiorite part of Rondonian-San Ignacio Province basement, southweast of Amazonian Craton, correspond to oriented bodies according to a NW/SE trend. The rocks are granodiorite composition with subordinate monzogranites, fine to coarse grained, consisting essentially of plagioclase, quartz, microcline, orthoclase and biotite. The accessory minerals are amphibole, titanite, garnet, apatite, epidote, zircon and opaque minerals. There is evidence of at least three phases of ductile deformation where the main structure is related to D1 stage (foliation S1), represented by a compositional banding, or by schistosity. The second phase is a crenulation cleavage transposing the foliation S1 and the third phase is exemplified by the deployment of shear zones that generated a foliation/fracturing on a local scale. The geochemical study indicates that the rocks are classify as granodiorites and monzogranites, coming from an intermediate to acid magmatism, sub-alkaline character calc-alkaline to high-K calc-alkaline series, with alumina ratios ranging from metaluminous to lightly peraluminous. The rocks were generate in a volcanic islands arc environment and the UPb data (Shrimp zircon) show a concord age 1575 ± 6Ma. The Sm-Nd model age (TDM) is 1.63Ga with εNd (t = 1.57Ga) ranging between -1.52 and +0.78. These data indicate that these rocks probably are a juvenile crust with a possible contamination of crustal rocks. Keyword: Geology, Gneiss Taquarussu, Granodiorite Guadalupe.
113

Is?topos de Nd na proveni?ncia de rochas e sedimentos da Bacia Potiguar, NE do Brasil

Maruoka, Miriam Tyoka da Silva 04 May 2007 (has links)
Made available in DSpace on 2015-03-13T17:08:28Z (GMT). No. of bitstreams: 1 MiriamTSM_DISSERT.pdf: 746109 bytes, checksum: 9993efc70026d11b86a511c7cf5aa9bc (MD5) Previous issue date: 2007-05-04 / Nd ISOTOPES IN THE PROVENANCE OF TERRIGENOUS AND CARBONATE ROCKS AND SEDIMENTS OF THE POTIGUAR BASIN, NORTHEASTERN BRAZIL. Mesozoic and Cenozoic rocks from the Potiguar Basin, including terrigenous and carbonate sediments have been investigated to identify their isotopic signature and source areas. Additionally, this study aims to determine the provenance of terrigenous and carbonate sediments on the Brazilian Continental shelf adjacent to Potiguar Basin. The Sm-Nd isotopic signatures of the rocks yielded model ages (TDM) in the range of 2,19- 2,88 Ga, indicating archean to paleoproterozoic sources from the basement. The terrigenous sediments yielded model ages (TDM) in the range of 2,31-2,26 Ga, from 17,5 to 0 cm depth. Despite the small number of samples, limited variations of provenance ages indicates the homogenization of the sediments, probably due to the strong influence of the basement, as the main source of sediments to the shelf. The Sm-Nd isotopic signatures of the carbonate sediments yielded model ages (TDM) in the range of 2,09-2,61 Ga, indicating archean to paleoproterozoic sources from the basement. The results also indicate that the shelf sediments are mainly derived from the A?u River or other small rivers from the Setentrional Sector of Rio Grande do Norte State. The littoral drift doesn?t seem to contribute with sediments from the Oriental Sector since isotopic signatures from this sector were not detected. / An?lises isot?picas Sm-Nd em rochas mesoz?icas e cenoz?icas da Bacia Potiguar, incluindo sedimentos terr?genos e carbon?ticos que aportam do Rio Piranhas-A?u, foram realizadas objetivando a caracteriza??o de suas assinaturas isot?picas e identifica??o de suas ?reas fonte. As assinaturas isot?picas Sm-Nd das rochas apresentaram idades modelo (TDM) variando de 2,88 a 2,19 Ga, indicando fontes, principalmente, paleoproteroz?icas e arquenas do embasamento. Os sedimentos terr?genos plataformais apresentaram idades modelo (TDM) de 2,31 Ga e 2,26 Ga, coletados, respectivamente, nas profundidades de 10-17,5 cm e 0-5 cm. Apesar do n?mero pequeno de amostras, a pequena varia??o na idade indica homogeneiza??o dos sedimentos, talvez devido a forte influ?ncia do embasamento como fonte de material para a plataforma. As assinaturas isot?picas Sm-Nd dos sedimentos carbon?ticos plataformais apresentaram idades modelo (TDM) variando de 2,61 a 2,09 Ga, indicando fontes do embasamento arqueano a paleoproteroz?ico. Estes resultados indicam ainda que os sedimentos terr?genos presentes na plataforma em estudo s?o ou foram trazidos principalmente pelo rio A?u, ou outros rios menores da por??o setentrional do Rio Grande do Norte. A deriva litor?nea aparentemente n?o tem compet?ncia para arrastar sedimentos da por??o oriental para a setentrional, tendo em vista que os valores ?Nd registrados n?o s?o compat?veis com as rochas da por??o oriental.
114

Litogeoquímica, geocronologia (U-Pb) e geoquímica isotópica (Sr-Nd) dos granitoides do Domínio Cambuci (Faixa Ribeira) na região limítrofe dos Estados do Rio de Janeiro e Espírito Santo / Litogeochemistry, geochonology (U-Pb) and isotope geochemistry (Sr-Nd) of granitoids in Cambuci Domain (Ribeira Belt) between Rio de Janeiro and Espírito Santo states

Rodson de Abreu Marques 09 March 2015 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / Os granitoides do Domínio Cambuci, na região limítrofe entre os estados do Rio de Janeiro e Espírito Santo, foram separados em quatro principais grupos: (1) Complexo Serra da Bolívia (CSB) - Ortogranulitos e Ortognaisses Heterogêneos; Ortognaisse Cinza Foliado; e charnockitos da Região de Monte Verde (2) Leucogranitos/leucocharnockitos gnaissificados da Suíte São João do Paraíso (SSJP) (3) Granito Cinza Foliado (4) Leucogranito isotrópico. O CSB é caracterizado pelo magmatismo de caráter calcioalcalino do tipo I, oriundo em ambiente de arco vulcânico (Suíte Monte Verde) e retrabalhamento crustal (ortogranulitos leucocráticos). O Ortogranulito esverdeado fino, é considerado no presente estudo como rocha do embasamento para o Terreno Oriental, cristalizada durante o paleoproterozoico - Riaciano (2184,3 21 Ma) e recristalizada durante o evento metamórfico Brasiliano no neoproterozoico - Edicariano (607,2 1,5 Ma), cuja idade TDM é de 2936 Ma. O Ortogranulito leucocrático médio cristalizou-se no neoproterozoico Edicariano (entre 592 e 609 Ma) e idade TDM ca. 2100 Ma, ao qual apresenta registro de herança no paleoproterozoico. A Suíte Monte Verde caracteriza-se por um magmatismo calcioalcalino e a Suíte Córrego Fortaleza, por um magmatismo calcioalcalino de alto K, ambas com assinatura de arco magmático. Registram dois pulsos magmáticos, em no Neoproterozoico - Edicarano: um em 592 2 Ma, idade do charnoenderbito, com idade TDM 1797 Ma, e outro em 571,2 1,8 Ma (injeção de um charnockitoide). Para todas as rochas do CSB são registradas feições protomiloníticas, miloníticas e localmente ultramiloníticas. Os dados geoquímicos indicam que os granitoides da SSJP são da série calcioalcalina de alto K, gerados no Neoproterozoico (idades que variam desde 610,3 4,7 Ma até, 592,2 1,3 Ma. As idades TDM revelam valores discrepantes para duas amostras: 1918 Ma e 2415 Ma, sugerindo que tenham sido geradas de diferentes fontes. O Granito Cinza Foliado é da Série Shoshonítica, metaluminoso do tipo I e, de ambiência tectônica de granitos intraplaca. Entretanto, poderiam ter sido fomados em ambiente de arco cordilheirano, havendo contaminação de outras fontes crustais. Fato este pode ser confirmado pelas as idades TDM calculadas ≈ 1429 1446 Ma. O Leucogranito isotrópico ocorre em forma de diques de direção NW, possui textura maciça e é inequigranular. Dados geoquímicos revelam que são granitoides metaluminosos do tipo I da série shoshonítica, e, de acordo com a ambiência tectônica, são granitos intraplaca. O Leucogranito Isotrópico representa o magmatismo pós-colisional ao qual ocorreu entre 80 a 90 Ma de anos após o término do evento colisional na região central da Faixa Ribeira. O Leucogranito Issotrópico cristalizou-se no cambriano (512,3 3,3 Ma e 508,6 2,2 Ma) e com idades TDM ca. 1900 / The granitoids of Cambuci Domain, situated between Rio de Janeiro and Espírito Santo states, were divided into four main groups: (1) Serra Bolivia Complex (CSB) - Heterogeneous Orthogranulites and Orthogneisses; Grey Fine grained Orthogneiss; and charnockites of Monte Verde Region (2) leucogranites / leucocharnockites gness of the São João do Paraíso Suite (SSJP) (3) Grey Foliated Granite (4) Isotropic Leucogranite. The CSB is characterized by type I calc character of magmatism, generate in volcanic arc environment (Monte Verde Suite) and crustal reworking (Leucocratic ortogranulites). The Fine grained Greenish, is considered in this research as the embasement rock for the Oriental Terrain, crystallized during the Paleoproterozoic - Riacian (2184.3 21 Ma) and recrystallized during in the metamorphic event in the Neoproterozoic - Edicarian (607.2 1.5 Ma), whose TDM age is 2936 Ma. The Medium grained Leucocratic Ortogranulite was crystallized in the Neoproterozoic - Edicarian (between 592 and 609 Ma) and its TDM age is ca. 2100 Ma, which features heritage record in the Paleoproterozoic. The Monte Verde Suite is characterized by a magmatism calcialcalin and the Córrego Fortaleza Suite, magmatism calc-alkaline high K, both show magmatic arc signature. Records two magmatic pulses in a sample (JP-RM-08A) in the Neoproterozoic - Edicaran: the first one in 592 2 Ma, and TDM age 1797 Ma, and the second one in 571.2 1.8 Ma (injecting a charnockitoids). For all CSB rocks, protomylonítics, Mylonitic and locally ultramilonítics features were portrayed. Geochemical data show these SSJP granitoids are the calc-alkaline series of high-K, crystallyzed in Neoproterozoic (ranging from 610.3 4.7 Ma to 592.2 1.3 Ma). TDM ages show outliers in two samples: 1918 Ma and 2415 Ma, suggesting that have been generated from different sources. The Gray Foliated Granite belongs to the shoshonitic series, type I and metaluminous and are intraplate granites. However, could have been formed into arc cordilheirano, with crustal contamination of other sources. This fact would be confirmed by the TDM ages calculated ≈ 1429 - 1446 Ma. The Isotropic Leucogranite occurs in the form of dykes, NW direction, has massive texture and is inequigranular. Geochemical data show these granitoids are metaluminous the type I shoshonitic series. They are intraplate granites. The Isotropic Leucogranite represents the post-collisional magmatism which took place between 80 and 90 Ma years after the collisional event in central sector of Ribeira Belt. It is crystallized in the Cambrian (512.3 3.3 Ma e 508.6 2.2 Ma) and TDM ages, ca. 1900 Ma
115

O complexo Juiz de Fora na região de Três Rios (RJ): litogeoquímica, geocronologia U-Pb (LA-ICPMS) e geoquímica isotópica de Nd / The Juiz de Fora Complex in the region of Três Rios (RJ): lithogeochemistry, geochronology e isotopic geochemistry of Nd

Jefferson Lima Fernandes André 24 March 2009 (has links)
Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O Complexo Juiz de Fora (CJF) na região de Três Rios (RJ) é constituído por uma ampla variedade composicional, tendo desde granitos, tonalitos a rochas de composição gabróica. Através da litogeoquímica pôde-se subdividir essa unidade em 4 conjuntos: (i) cálcioalcalino de alto-K, (ii) cálcioalcalino de médio-K, (iii) toleítico e (iv) alcalino. Pela análise geocronológica (LA-ICPMS, U-Pb) foi obtida a idade de 2,1Ga para o conjunto cácioalcalino de médio-K, duas idades neoproterozóicas (615.9 6.4 Ma e 589.1 5 Ma) foram datadas em um ortogranulito do conjunto toleítico, que foram interpretadas como sendo idades de metamorfismo. A idade modelo de Nd (≈ 2,37 Ga) e os dados de U-Pb e litogeoquímicos balizam a hipótese do conjunto cálcioalcalino de médio-K representar rochas de um arco magmático juvenil. A análise isotópica em conjunto com a litogeoquímica sugere que a série toleítica do CJF da região estudada foi gerada em ambiente de fundo oceânico, sendo diferenciada a partir de uma fonte depletada com alguma contribuição de uma fonte enriquecida. / The Juiz de Fora Complex (JFC) in the region of Três Rios (Rio de Janeiro) is appointed by an ample variety composicional, having from granites, tonalite to rocks of composition basic. Through the lithogeochemistry it was possible to subdivide this unity in 4 associations: (i) calc-alkaline of high-K, (ii) calc-alkaline of medium-K, (iii) tholeiitic and (iv) alkaline. By the geochronological analysis(LA-ICPMS, U-Pb) was obtained the age of 2,1Ga for the calc-alkaline group of medium-K, two ages neoproterozoic (615.9 6.4 Ma and 589.1 5 Ma) were dated in an orthogranulite of the toleítico group, what they were interpreted like ages of metamorphism. The model age of Nd (≈ 2,37 Ga) and the data of U-Pb and lithogeochemical mark the hypothesis of the calc-alkaline group of middle-K represents rocks of a youthful magmatic arc. The isotópica together with the lithogeochemistry analysis suggests that the toleítica group of the CJF of the studied region were produced in environment of ocean extensional, being differentiated from a fountain depletada with some contribution of a rich fountain.
116

Obtenção de pós e filmes finos do sistema SrTiO3:Nd / Obtention of Powders and Thin Films of the SrTiO3:Nd System

Silva, Marcia Rejane Santos da 15 December 2010 (has links)
Made available in DSpace on 2015-05-14T13:21:52Z (GMT). No. of bitstreams: 1 parte1.pdf: 2740601 bytes, checksum: 60bd87566aa111195ece86e01435aaf6 (MD5) Previous issue date: 2010-12-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / SrTiO3 is a compound with perovskite structure usually found with cubic phase. This works reports the synthesis of powders and thin films of the undoped and Nd3+ doped SrTiO3, replacing Ti4+ or Sr2+ with the stoichiometries SrTi1-xNdxO3 (x = 0.00; 0.01; 0.02; 0.04) and Sr0.99Nd0.01TiO3. The powders were synthesized by the polymeric precursor method. The thin films were prepared by chemical solution deposition (CSD) using the spin coating technique and by pulsed laser deposition (PLD), being deposited on LaAlO3 (100), MgO (100), SrTiO3 (100), Al2O3-R, and SiO2. The structural and optical properties of these materials were evaluated by infrared spectroscopy, UV-vis spectroscopy, photoluminescent emission, micro Raman spectroscopy and X-ray diffraction (XRD) Rietveld refinement of the XRD patterns was realized for powder samples. Moreover the photocatalytic property was evaluated in the degradation of textile dyes. The coexistence of the cubic and tetragonal phases for SrTiO3 powders was confirmed after calcinations at 550 oC. For doped samples calcined at 700 oC, it was observed that the sites occupied by Nd3+ influenced in the amount of these phases, leading to a direct influence in the photoluminescent emission. Emission in the yellow region was observed, while temperature increase lead to a shift to the green region, with higher energy indicating that short range ordering occurred. Thin films deposited on LaAlO3 substrate showed high quality epitaxial growth by CSD and a very high quality by PLD. On MgO doping changed the film orientation. For deposition on Al2O3-R and SiO2, polycrystalline films were obtained. Photocatalytic degradation efficiency was similar in powders and undoped films, increasing for films doped with 4 % of Nd3+ when synthesis was done by PLD. Key words: / SrTiO3 é um composto de estrutura perovskita comumente encontrado na fase cúbica. Este trabalho reporta a síntese de pós e filmes finos deste composto na sua forma pura e dopada com Nd3+ em substituição a Ti4+ ou Sr2+ nas estequiometrias SrTi1-xNdxO3 (x = 0,00; 0,01; 0,02; 0,04) e Sr0,99Nd0,01TiO3. Os pós foram sintetizados pelo método dos precursores poliméricos. Os filmes finos foram preparados pelo método de deposição de solução química (CSD) utilizando a técnica spin coating e pelo método de deposição por laser pulsado (PLD), sendo depositados em substratos de LaAlO3 (100), MgO (100), SrTiO3 (100), Al2O3-R, e SiO2. As propriedades estruturais e óticas desses materiais foram avaliadas por espectroscopia de infravermelho, espectroscopia UV-Vis, espectroscopia de emissão fotoluminescente, espectroscopia micro Raman e difração de raios-X (DRX). Refinamento Rietveld dos dados de DRX foi realizado para algumas amostras em pó. Além disso, a propriedade fotocatalítica foi estudada frente à degradação de corantes têxteis. A coexistência das fases cúbica e tetragonal para os pós de SrTiO3 foi confirmada, já na temperatura de 550 ºC e foi verificado para as amostras dopadas (700 ºC) que o sítio de ocupação do Nd3+ influenciou na quantidade dessas fases. Esse resultado teve influência direta na propriedade fotoluminescente observada. Os materiais emitiram principalmente na região do amarelo, mas com o aumento da temperatura essa região se deslocou para o verde (maior energia) indicando a organização do sistema. Os filmes finos depositados sobre o substrato de LaAlO3 mostraram crescimento epitaxial de alta qualidade por CSD e de qualidade muita alta por PLD. Sobre MgO a dopagem influenciou na orientação dos filmes. Os filmes depositados em Al2O3-R, e SiO2 foram policristalinos. A eficiência de degradação fotocatalítica foi similar entre pós e filmes puros, sendo aumentada com 4 % de Nd3+ nos filmes depositados por PLD.
117

Análise integrada de métodos moleculares e sorológicos para diagnóstico de hanseníase e monitoramento de contatos domiciliares

Gama, Rafael Silva 30 October 2017 (has links)
Submitted by Geandra Rodrigues (geandrar@gmail.com) on 2018-04-10T18:04:35Z No. of bitstreams: 1 rafaelsilvagama.pdf: 1774054 bytes, checksum: b50899947c904ace42800056fa0d9afc (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-04-11T15:19:43Z (GMT) No. of bitstreams: 1 rafaelsilvagama.pdf: 1774054 bytes, checksum: b50899947c904ace42800056fa0d9afc (MD5) / Made available in DSpace on 2018-04-11T15:19:43Z (GMT). No. of bitstreams: 1 rafaelsilvagama.pdf: 1774054 bytes, checksum: b50899947c904ace42800056fa0d9afc (MD5) Previous issue date: 2017-10-30 / O diagnóstico da hanseníase é eminentemente clínico, podendo ser complementado com baciloscopia, histopatologia e testes imunológicos. Métodos bacteriológicos clássicos para identificação de bactérias patogênicas não podem ser aplicados para o diagnóstico de hanseníase, sobretudo pela impossibilidade de cultivo in vitro do M. leprae. O exame histopatológico e a baciloscopia têm sido utilizados como métodos auxiliares para a classificação clínica dos casos. Técnicas moleculares e sorológicas têm sido avaliadas como ferramentas de diagnóstico na hanseníase. Ao contrário da baciloscopia, que requer cerca de 104 organismos por grama de tecido para detecção real, a PCR é uma técnica de alta especificidade e sensibilidade, capaz de detectar 25 fg (10-15g) de DNA de M. leprae. Além disso, a possibilidade de sua utilização em quase todos os tipos de amostras clínicas confere a este método um alto potencial para o diagnóstico diferencial. Os testes sorológicos têm como alvo a detecção de anticorpos específicos contra o M. leprae que indicam infecção. Esses testes podem ser úteis no monitoramento da eficácia da terapia, na determinação da prevalência da doença e na avaliação da distribuição da infecção entre contatos domiciliares. Considera-se que o indivíduo que reside ou tenha residido com o doente de hanseníase apresenta maior risco de adoecimento em relação à população em geral, pelo fato de estarem expostos ao M. leprae. Familiares de pacientes Multibacilar e Paucibacilar devem ser examinados, independente do tempo de convívio. Sugere-se avaliar anualmente, durante cinco anos, todos os contatos não doentes, quer sejam familiares ou sociais. Neste estudo utilizou-se o suporte da Inteligência Artificial (Random Forest) para análise integrada de métodos sorológicos e moleculares, no diagnóstico de novos casos de hanseníase e monitoramento de contatos domiciliares por um período de cinco anos. O estudo foi desenvolvido em Governador Valadares – MG, considerada área endêmica de hanseníase. O desenho proposto é do tipo longitudinal, com coleta de dados cadastrais de todos os casos diagnosticados em 2011 e seus respectivos contatos domiciliares registrados no período de 2011, 2012 e 2016. Um total de 196 indivíduos, sendo 43 casos, 113 contatos domiciliares e 40 indivíduos considerados controles endêmicos que relataram não ter convívio com pacientes com hanseníase nem tão pouco histórico de hanseníase na família foi incluído no estudo. Foram coletadas amostras sangue e de raspado intradérmico dos casos de hanseníase e seus respectivos contatos domiciliares, para análise por qPCR (16S rRNA) e ELISA (anti NO-OLID e LID-1). A análise integrada dos dados foi realizada por meio da Random Forest com o objetivo de melhorar o desempenho dos testes para o diagnóstico de hanseníase. Isoladamente, a qPCR apresentou sensibilidade de 48,8% e especificidade de 100% no diagnóstico de casos de hanseníase. No ensaio de ELISA anti-ND-O-LID a sensibilidade alcançada foi de 57,9% e especificidade de 97,5%, enquanto que no ensaio de anti-LID-1, a sensibilidade e especificidade foram de 63,2% e 92,5%, respectivamente. Entretanto, a análise integrada dos dados por Random Forest, utilizando 10.000 árvores de decisão, com um erro modal de 12,8%, obteve-se uma taxa de sensibilidade de 81,6% e especificidade de 92,5% na predição de novos casos de hanseníase. O modelo de Random Forest foi utilizado para o monitoramento de contatos domiciliares no período de 05 anos. Esta ferramenta de análise identificou entre os contatos, 02 doentes, mesmo antes do diagnóstico clínico. Ao final do período de acompanhamento, 03 contatos domiciliares foram notificados como casos novos de hanseníase. Desta forma, o modelo proposto pela análise Random Forest permitiu diagnosticar casos de hanseníase com alta sensibilidade e especificidade e identificar precocemente novos casos entre os contatos domiciliares durante o monitoramento. / The diagnosis of leprosy is eminently clinical and may be supplemented with bacilloscopy, histopathology and immunological tests. Classical bacteriological methods for the identification of pathogenic bacteria can not be applied for the diagnosis of leprosy, mainly due to the impossibility of in vitro culture of M. leprae. Histopathological examination and smear microscopy have been used as auxiliary methods for the clinical classification of cases. Molecular and serological techniques have been evaluated as diagnostic tools in leprosy. Unlike smear microscopy, which requires about 104 organisms per gram of tissue for actual detection, PCR is a technique of high specificity and sensitivity, capable of detecting 25 fg (10-15g) of M. leprae DNA. In addition, a possibility of its use in almost all types of clinical specimens gives this method a high potential for differential diagnosis. Serological tests are aimed at detecting specific antibodies against M. leprae that indicate infection. These tests may be useful in monitoring therapy efficacy, in determining disease prevalence, and in assessing the distribution of infection between household contacts. It is considered that the individual who resides or has lived with the leprosy patient has a higher risk of becoming ill in relation to the general population due to the fact that they are exposed to M. leprae. Relatives of patients Multibacillary and Paucibacillary should be examined, regardless of the time of conviviality. It is suggested to evaluate annually, for five years, all non-sick contacts, whether family or social. In this study we used the support of Artificial Intelligence (Random Forest) for integrated analysis of serological and molecular methods, in the diagnosis of new cases of leprosy and monitoring of household contacts for a period of five years. The study was developed in Governador Valadares - MG, considered an endemic area of leprosy. The proposed design is of the longitudinal type, with the collection of cadastral data of all cases diagnosed in 2011 and their respective household contacts registered in the period of 2011, 2012 and 2016. A total of 196 subjects, including 43 cases, 113 household contacts and 40 individuals considered endemic controls who reported not having lived with patients with leprosy or a history of leprosy in the family were included in the study. Blood samples and intradermal scrapings were collected from leprosy cases and their respective household contacts for analysis by qPCR (16S rRNA) and ELISA (anti-ND-O-LID and LID-1). The integrated analysis of the data was performed through Random Forest with the objective of improving the performance of the tests for leprosy diagnosis. In isolation, the qPCR showed sensitivity of 48.8% and specificity of 100% in the diagnosis of leprosy cases. In the anti-NDO- LID ELISA the sensitivity reached was 57.9% and specificity was 97.5%, whereas in the anti-LID-1 assay the sensitivity and specificity were 63.2% and 92.5%, respectively. However, the integrated analysis of the data by Random forest, using 10,000 decision trees, with a modal error of 12.8%, obtained a sensitivity rate of 81.6% and specificity of 92.5% in the prediction of new cases of leprosy. The Random Forest model was used to monitor household contacts within a period of 5 years. This analysis tool identified between the contacts, 02 patients, even before the clinical diagnosis. At the end of the follow-up period, 03 household contacts were reported as new cases of leprosy. Thus, the model proposed by the Random Forest analysis allowed the diagnosis of leprosy cases with high sensitivity and specificity and early identification of new cases among household contacts during monitoring.
118

Erschließung domänenübergreifender Informationsräume mit Multimodellen / Access of cross-domain information spaces using multi-models

Fuchs, Sebastian 23 October 2015 (has links) (PDF)
Mit dem Übergang von bauwerksorientierter zu prozessorientierter Arbeitsweise erlangt die domänenübergreifende Bereitstellung von Informationen wachsende Bedeutung. Das betrifft bspw. die Erstellung von Controlling-Kennwerten, die Vorbereitung von Simulationen oder die Betrachtung neuer Aspekte wie Energieeffizienz. Aktuelle Datenformate und Erschließungsmethoden können diese Herausforderung jedoch nicht befriedigend bewältigen. Daher bedarf es einer Methode, welche interdisziplinäre Bauinformationsprozesse uneingeschränkt ermöglicht. Vorhandene Kommunikationsprozesse und Fachanwendungen sollen dabei beibehalten und weitergenutzt werden können. Mit der Multimodell-Methode wird ein Lösungsansatz für die strukturellen Probleme interdisziplinärer Bauinformationsprozesse vorgestellt. Multimodelle bündeln heterogene Fachmodelle unterschiedlicher Domänen und erlauben die Verbindung ihrer Elemente in externen, ID-basierten Linkmodellen. Da die Fachmodelle unberührt bleiben, wird auf diesem Weg eine lose und temporäre Kopplung ermöglicht. Durch den Verzicht auf ein führendes oder integrierendes Datenschema werden keine Transformationsprozesse benötigt, können etablierte und heute übliche Datenformate weitergenutzt und die verlinkten Fachmodelle neutral ausgetauscht werden. Die in Multimodellen verknüpften Daten bieten einen informationellen Mehrwert gegenüber alleinstehenden Fachmodellen. Zusammengehörende Informationen können über die persistenten Links automatisch ausgewertet werden, anstelle manuell vom Menschen immer wieder flüchtig neu zugeordnet werden zu müssen. Somit erscheint ein Multimodell gegenüber einem Benutzer wie ein einziger abgeschlossener Informationsraum. Um solche datenmodell-, datenformat- und domänenübergreifenden Informationsräume komfortabel erstellen und filtern zu können, wird die deklarative Multimodell-Abfragesprache MMQL eingeführt. Diese erlaubt einen generischen Zugriff auf die Originaldaten und bildet die Kernkonzepte der Multimodell-Erschließung - mehrwertige Linkerzeugung und strukturelle Linksemantik - ab. Ein zugehöriger Interpreter ermittelt den Lösungsweg für konkrete Anweisungen und führt diesen auf realen Daten aus. Die Umsetzung und Bereitstellung der Konzepte als IT-Komponenten auf verschiedenen Ebenen - von der Datenstruktur über Bibliotheken und Services bis hin zur alleinstehenden, universellen Multimodell-Software M2A2 - erlaubt die sofortige und direkte Anwendung der Multimodell-Methode in der Praxis. / With the transition of building-oriented to process-oriented work, the provision of cross-domain information gained growing importance - for example in the creation of controlling parameters, the preparation of simulations or when considering new aspects such as energy efficiency. However, current data formats and access methods cannot cope with this challenge satisfactory. Therefore, a method is required, that enables interdisciplinary construction information processes fully. Thereby existing communication processes and domain applications have to be retained and continued to be used as possible. With the multi-model method, an approach to structural problems of such interdisciplinary construction information processes is presented. Multi-models combine heterogeneous models of different domains and allow the connection of their elements in external ID-based link models. As the domain models remain unaffected, a loose and temporary coupling is possible in this way. By not using a leading or integrating data schema, no transformation processes are required, common established data formats can be retained and the linked domain models can be exchanged neutrally. The linked data in multi-models offer an additional value of information over single domain models. Information belonging together can be automatically evaluated by the persistent links - instead of being repeatedly reassigned by people in a volatile way. Thus, a multi-model appears to a user as a single self-contained information space. In order to create and filter such cross-format and cross-domain information spaces comfortably, the declarative multi-model query language MMQL is introduced. It allows for generic access to the original data and integrates the core concepts of the multi-model development - n-ary link generation and structural link semantics. An associated interpreter determines the approach for specific instructions and executes it on real data. The implementation and deployment of the concepts as IT components at various levels - from the data structure via libraries and services, to the universal multi-model software M2A2 - allows an immediate and direct application of the multi-model method in practice.
119

Les tourbières ombrotrophes en tant qu'archives de la variabilité des apports de poussières atmosphériques holocènes au Québec boréal - Implications paléoenvironnementales et paléoclimatiques. / Peat bogs as archives of the variability of holocene dust deposition in boreal Quebec - Paleoenvironmental and paleoclimatic implications

Pratte, Steve 06 June 2016 (has links)
Les poussières atmosphériques naturelles jouent un rôle complexe dans le système climatique global étant à la fois un facteur affectant le climat et variant en fonction de ce dernier. Notre compréhension des différentes interactions entre les poussières atmosphériques et le climat est limitée par l’importante variabilité spatiale et temporelle des celles-ci. À l’aide de tourbières ombrotrophes, la variabilité spatiale et temporelle des dépôts de poussières atmosphériques holocènes au Québec boréal fut caractérisée en lien avec les fluctuations climatiques. Les flux de poussières atmosphériques furent reconstruits à l’aide des concentrations en terres rares. Les isotopes du Nd et Pb en combinaison avec les terres rares ont été utilisés afin de déterminer la source des particules déposées dans les tourbières. Afin d’évaluer les liens entre les flux de poussières et la variabilité climatique, les changements temporels dans les flux de poussières et l’isotopie du Nd furent comparés à la taille des particules déposée et des reconstitutions écohydrologiques basées sur l’analyse des macrorestes végétaux et des thécamoebiens. Dans les deux premiers volets de l’étude, les flux de poussières atmosphériques furent reconstruits dans deux tourbières de la Côte-Nord alors que les particules déposées dans celles-ci furent caractérisées à l’aide des concentrations des terres rares (REE), des isotopes du néodyme et du plomb ainsi que la granulométrie. Les deux profils présentent des valeurs de Nd similaires, ce qui s’explique soit par une source commune des poussières atmosphériques ou encore des sources distinctes, mais possédant des valeurs de Nd similaires dans les deux régions. Les deux sites étudiés montrent des tendances différentes dans les flux de poussières. La tourbière IDH montre peu de variations dans les flux de poussières, ce qui s’explique en partie par l’emplacement du site d’étude, qui prévient les apports de poussières atmosphérique. La tourbière Baie quant à elle, montre deux périodes de flux de poussières plus élevés soit 1700-1000 et 650-100 cal a BP correspondant avec des périodes de refroidissement du climat documentées. Les REE, le Nd et les tailles de particules suggèrent qu’au cours des 2000 dernières années, la tourbières de Baie a reçu une proportion accrue de poussières atmosphériques provenant de sources locales. Ces deux périodes ont été identifiées comme des épisodes d’instabilité climatique en réponse à une instabilité hydroclimatique régionale et une plus grande variabilité des températures (principalement contrôlée par l’activité solaire). Un changement du régime des vents dans la région a aussi probablement influencé ces les variations observées. Dans le troisième chapitre, les mêmes analyses furent réalisées sur des carottes de tourbe d’une tourbières de la Baie James, La Grande 2 (LG2). Des apports accrus de poussières furent observés lors de différentes période : 4000 à 3000, 2600 à 2000, 1600 à 1000, 800 à 650 cal a BP et de 1960 à 1990AD. Au moins trois sources distinctes constituent les apports de poussières dans le temps: les sédiments marins à la base de la tourbières, la moraine de Sakami, deux sources locales, ainsi qu’une source probablement plus régionale dont l’origine est non-identifiée. La période allant de 7000 à 4100 cal a BP montre des valeurs près des sources locales (Nd : -36 à -29). Une augmentation graduelle des valeurs de Nd à partir de 4100 cal a BP suggère une diminution des apports locaux de poussière à la faveur d’une source non identifiée. La majorité des périodes d’apports accrus de poussières identifiées correspondent à des périodes documentées comme étant froides et sèches probablement lié à des intrusions de masses d’air arctiques. La présence de certains de ces pics de poussières lors de minimums solaires suggère que la variabilité solaire joue aussi un rôle dans la variabilité climatique de la région. / Mineral dust plays an important role in the global climate system having effects on the radiation budget and the chemical composition of the atmosphere. Our understanding of the exact role of dust in the Earth’s climate system is still poorly constrained mostly due to a lack of data reflecting the high spatial and temporal variability of dust. Using peat bogs, spatial and temporal variability of Holocene dust deposition in boreal Quebec was investigated in relation to climate fluctuations. Dust fluxes were reconstructed using rare earth elements (REE) concentrations in bulk peat, while Nd and Pb isotopes in combination with REE were used to identify the source of dust particles deposited into these bogs. In order to evaluate the relationship between dust fluxes and climate variability, temporal changes in dust flux, and Nd isotopes were compared to dust grain size and ecohydrological reconstructions derived from testate amoebae and plant macrofossils. In two peat bogs from the North Shore region of the St. Lawrence Estuary (Baie bog) and Gulf (IDH bog), atmospheric dust fluxes were reconstructed using REE concentration while the geochemical composition of deposited dust was characterized using Nd and Pb isotopes combined with REE and grain size. Both peat bogs present similar Nd values, which suggests either a common source or sources with similar signatures in both regions. In terms of dust flux, the two study sites display distinct tendencies. IDH bog show few variations in dust flux, which can be explained by its geographical setting, where a tree fringe and higher altitude likely partially prevent dust from reaching the peat bog. Two dust events were recorded in the Baie bog from 1750 to 1000 cal BP and 600 to 100 cal BP and correspond to documented cold periods. These two periods have been found to occur at the same time as periods of high variability in the macrofossil record (i.e. successive layers dominated by Sphagnum or Ericaceae). REE elements, Nd and grain-size distribution suggest that, over the last 2000 years, the Baie bog received more local dust. The two periods were identified as periods of increased local storminess in response to regional hydroclimatic instability and temperature variations mainly controlled by solar activity. These episodes of climatic instability could also have been caused by changes in the wind regime. The same set of analyses were performed in a third peatland located in the James Bay region, the La Grande 2 bog (LG2). Increases in dust flux were reconstructed from 4000-3000, 2600-2000, 1600-1000, 800-650 cal BP and from 1960-1990AD. The Nd values show a large variability from -37 to -12, identifying a least three sources: local marine sediment, the Sakami moraine and another unidentified source likely from a more regional origin. Between 7000 and 4100 cal BP, Nd values resemble those localsources (-36 to -29). A gradual increase in Nd signature is observed from 4100 to 1500 cal BP suggesting a decreasing influence of local sources in favor of a yet unidentified source. The occurrence of increased dust deposition during cold periods in two of the three studied bogs suggests that dust fluxes can be used as an indicator of cold and dry climatic conditions in boreal Quebec. In northeastern Canada, these cold and dry conditions are usually the results of the intrusion of Arctic air masses. The exact mechanism controlling these incursion is yet unknown, but the similar timing of solar minima and dust peaks suggest that solar irradiance may also have played a role. The fact that both Baie and LG2 sites display similar tendencies during the last 2000 years reveals that both regions were likely controlled by the same climatic processes.
120

Structural and magnetic characterization of Nd-based Nd-Fe and Nd-Fe-Co-Al metastable alloys

Kumar, Golden 27 May 2005 (has links)
The aim of the present work is to characterize a metastable hard magnetic phase referred to as "A1" in Nd-Fe alloys, which forms as a part of the fine eutectic depending on the composition and cooling rate. In order to define the range of composition for the formation of A1, Nd100-xFex (x = 20, 25, 40) alloys are cooled at about 150 K/s. The results indicate that for a cooling rate of 150 K/s, the hypereutectic Nd100-xFex (x = 20) alloys solidify into hard magnetic A1 whilst the hypoeutectic alloys (x = 40) show the formation of Nd2Fe17 crystallites. However, no sample cooled at 150 K/s shows the peaks of Nd5Fe17 as expected from the equilibrium Nd-Fe phase diagram. The effect of cooling rate on the formation of hard magnetic A1 is studied by investigating the Nd80Fe20 alloys cooled at different rates. The microstructure of hard magnetic Nd80Fe20 alloys displays a fine eutectic-like matrix consisting of Nd-richer and Fe-richer regions. The Nd-richer regions are identified as dhcp Nd and fcc Nd-Fe solid solution. However, the Fe-richer regions also referred to as A1, are diffuse and give an average composition of Nd56Fe44. These regions yield complex electron diffraction patterns, which do not match with any known Nd-Fe phase. HRTEM images of the Fe-richer regions reveal the presence of 5-10 nm crystallites embedded in an amorphous phase. Thus the Fe-richer regions of the hard magnetic Nd80Fe20 specimens are not a single homogeneous phase rather they are mixture of finely dispersed nanocrystallites in an amorphous phase. The demagnetization curves the hard magnetic Nd80Fe20 measured at temperatures above 30 K are typical of a hard magnetic material. The coercivity increases from 0.48 to 4.4 T with the temperature decreasing from 300 to 55 K. The demagnetization curves change from single to two-phase type when the temperature approaches 29 K, ordering temperature of fcc Nd-Fe solid solution. The measurements of initial magnetization, field dependence of coercivity, and temperature dependence of coercivity suggest the Stoner-Wohlfarth type magnetization reversal process for the hard magnetic A1. The values of anisotropy constant are estimated by fitting the magnetization data to the law-of-approach to saturation. The temperature dependence of anisotropy constant and the coercivity indicate that the origin of coercivity is magnetic anisotropy. A cluster model with sperimagnetic arrangement of Nd and Fe spins is used to explain the hard magnetic behavior of the mold-cast Nd80Fe20. Structural and magnetic properties of multicomponent Nd60Co30-xFexAl10 (0 < x < 30) alloys are compared with the binary Nd-Fe alloys. Magnetic measurements of the multicomponent alloys show that the magnetic properties are controlled by the fraction of the Fe content. The coercivity of the Nd60Co30-xFexAl10 mold-cast rods does not vary much with the Fe-content for more than 10 at.% Fe but the remanence and the maximum magnetization increase linearly with the Fe content. The temperature dependence of coercivity, effective anisotropy constant, and anisotropy field are identical to those for the binary Nd80Fe20 mold-cast rod. These results clearly suggest that the binary Nd80Fe20 and the multicomponent Nd60Co30-xFexAl10 (x > 5) mold-cast rods are magnetically identical.

Page generated in 0.0582 seconds