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  • 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.
41

Caracterizacao de componentes inorganicos e tipos de polimeros em materiais plasticos metalizados

SOARES, EUFEMIA P. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:47:44Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:08:16Z (GMT). No. of bitstreams: 1 08316.pdf: 3292431 bytes, checksum: 351990e9278a88c1aa015f5320b23c32 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
42

Estudos microestruturais e microanalise de fases intermetalicas presentes na producao do silicio grau quimico

MORCELLI, APARECIDO E. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:47:52Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:08:07Z (GMT). No. of bitstreams: 1 08328.pdf: 5698756 bytes, checksum: 666e31b1eb88511baa0febca1d995e14 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
43

Avaliacao da contaminacao por mercurio dos sedimentos do estuario Santos - Sao Vicente, no periodo de 1996 - 2000

HORTELLANI, MARCOS A. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:47:58Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:07:58Z (GMT). No. of bitstreams: 1 09022.pdf: 7421043 bytes, checksum: 44a990a45b4428a51fbaede4e9638fd1 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
44

Estudo da composição inorgânica e avaliação da atividade biológica de Peperomia pellucida no crescimento de Aspergillus flavus / Inorganic composition determination and evaluation of the biologic activity of Peperomia pellucida in the Aspergillus flavus growth

SUSSA, FABIO V. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:34:23Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:10:32Z (GMT). No. of bitstreams: 0 / Nas últimas décadas houve um grande avanço em pesquisas no desenvolvimento de medicamentos à base de plantas medicinais. Entretanto, constata-se que há pouca preocupação sobre as concentrações de elementos estáveis, bem como as concentrações de atividade de radionuclídeos naturais das séries do 238U e 232Th em plantas com esta finalidade no Brasil. A presença de minerais e radionuclídeos em plantas constitui um meio de migração destes elementos para o organismo humano, através da ingestão de chás ou medicamentos feitos com ervas medicinais. Peperomia pellucida é conhecida popularmente por erva de jabuti e por suas propriedades medicinais, como cicatrizante, analgésica, bactericida e fungicida. As amostras de Peperomia pellucida e de solo analisadas neste trabalho foram coletadas no Jardim Botânico do Rio de Janeiro e em suas proximidades. A concentração elementar de As, Ba, Br, Ce, Cl, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Mg, Mn, Na, Nd, Rb, Sb, Sc, Sm, Ta, Tb, Th, U, Yb e Zn foi determinada nas folhas, partes aéreas, compreendendo folhas e caule, e raiz de Peperomia pellucida, nos extratos obtidos por maceração e infusão e no solo pela técnica da Análise por Ativação Neutrônica Instrumental (AANI). O método analítico utilizado para determinar os elementos Cd, Hg e Pb foi a Espectrometria por Absorção Atômica e as atividades de 226Ra, 228Ra e 210Pb foram determinadas pela contagem alfa e beta total após separação radioquímica. A qualidade dos resultados obtidos foi verificada pela análise dos materiais de referência certificados IAEA-336 Lichen, IAEA-Soil-7, IAEA-326 Radionuclides in soil, NIST 1515 Apples Leaves e NIST 1542 Peach Leaves. Os resultados obtidos nas análises apresentaram boa precisão e exatidão. O óleo essencial e os extratos etanólico e hexânico obtidos das partes aéreas de P. pellucida foram testados in vitro, em placas de Petri, para verificar a atividade antifúngica diante ao fungo Aspergillus flavus. A atividade antifúngica baseou-se na zona de inibição e nos valores de CI50 frente ao patógeno. Também foi determinada a composição química do óleo essencial pela Cromatografia Gasosa acoplada ao Espectrômetro de Massa (GC-EM). / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
45

Traces of the Past : XRF analysis of soils samples from a medieval churchyard in Sigtuna, Sweden

Hobbs, Jeremy January 2020 (has links)
Sigtuna is one of the first settlements in Sweden considered to be a proper town. Taking over Birka´s function as a central trading hub when it was founded in the late 10th century AD, Sigtuna was characterized by its early connection to Christianity, and many churches were built there. The foundations of one of these medieval stone churches and its churchyard lie beneath Sigtuna museum’s plot on the block S: t Gertrud 3. However, the full extent of this church and churchyard as well as its foundation date and function is not fully known. The over-arching purpose of this study is to achieve a better understanding of this church’s function. This will be done by geochemically analysing soil samples taken from the museum plot under which the churchyard is located. The first aim of this study is to establish the extent of the churchyard. During excavations carried out between 1990- 1991 in the neighbouring block Urmakaren, archaeologists discovered the remains of King Olof Skötkonung’s minting house along with various finds, notably two lead pieces with imprints of coin stamps. The second aim of this study is to see if traces of these metalworking activities can be detected on the museum plot. The third aim is to see how the church and churchyard related to the minting house on a spatial plane.
46

Multivariate calibration for ICP-AES

Griffiths, Michael Lee January 2001 (has links)
The analysis of metals is now a major application area for ICP-AES, however, the technique suffers from both spectral and non-spectral interferences. This thesis details the application of univariate and multivariate calibration methods for the prediction of Pt, Pd, and Rh in acid-digested and of Au, Ag and Pd in fusion-digested autocatalyst samples. Of all the univariate calibration methods investigated matrix matching proved the most accurate method with relative root mean square errors (RRMSEs) for Pt, Pd and Rh of 2.4, 3.7, and 2.4 % for a series of synihelic lest solutions, and 12.0, 2.4, and 8.0 % for autocatalyst samples. In comparison, the multivariate calibration method (PLSl) yielded average relative errors for Pt, Pd, and RJi of 5.8, 3.0, and 3.5 % in the test solutions, and 32.0, 7.5, and 75.0 % in the autocatalyst samples. A variable selection procedure has been developed enabling multivariate models to be built using large parts of the atomic emission spectrum. The first stage identified and removed wavelengths whose PLS regression coefficients were equal to zero. The second stage ranked the remaining wavelengths according to their PLS regression coefficient and estimated standard error ratio. The algorithms were applied to the emission spectra for the determination of Pt, Pd and Rh in a synthetic matrix. For independent test samples variable selection gave RRMSEs of 5.3, 2.5 and 1.7 % for Pt, Pd and Rh respectively compared with 8.3, 7.0 and 3.1 % when using integrated atomic emission lines. Variable selection was then applied for the prediction of Au, Ag and Pd in independent test fusion digests. This resulted in RRMSEs of 74.2, 8.8 and 12.2 % for Au, Ag and Pd respectively which were comparable to those obtained using a more traditional univariate calibration approach. A preliminary study has shown that calibration drift can be corrected using Piecewise Direct Standardisation (PDS). The application of PDS to synthetic test samples analysed 10 days apart resulted in RRMSEs of 4.14, 3.03 and 1.88%, compared to 73.04, 44.39 and 28.06 % without correction, for Pt, Pd, and Rh respectively.
47

Determinacao de elementos metalicos em sedimentos da Baia do Almirantado, Ilha Rei George, Penisula Antartica

GOMES, MARCELO da S. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:43:43Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:58:06Z (GMT). No. of bitstreams: 1 06649.pdf: 21672592 bytes, checksum: ce3be21667c4c3939460ddeff380f31c (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
48

Avaliacao do conteudo de alguns elementos essenciais e toxicos em dietas de criancas e idosos pelo metodo de analise por ativacao de neutrons

MAIHARA, VERA A. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:38:48Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:55Z (GMT). No. of bitstreams: 1 02808.pdf: 3051127 bytes, checksum: ee0b80e362c14864a245ed624e93fff2 (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
49

Determinacao de mercurio tital e organico e avaliacao dos processos de metilacao e desmetilacao em sedimentos do reservatorio Rio Grande, Estado de Sao Paulo / Determination of total organic mercury and evaluation of methylation and demethylation processes in sediments of the Rio Grande reservoir, State of Sao Paulo

FRANKLIN, ROBSON L. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:28:00Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:01:28Z (GMT). No. of bitstreams: 0 / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
50

Determinacao de impurezas em compostos de uranio por meio da tecnica de espectrometria de massas de alta resolucao com fonte de plasma indutivo (HR-ICPMS)

ULRICH, JOAO C. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:46:10Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:01:57Z (GMT). No. of bitstreams: 1 07537.pdf: 6037545 bytes, checksum: e5c0c7ed539b9c85328768099422ceff (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

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