Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Neste trabalho utilizamos a tÃcnica de espectroscopia Raman para investigar as caracterÃsticas dos fÃnons de duas sÃries de cristais contendo elementos terras-raras: (i) arsenatos de terras-rara (REAsO4) e (ii) molibdatos de terras-rara (RE(MoO4)3). Para a sÃrie REAsO4 interpretamos os resultados de modo sistemÃtico baseado na estrutura tetragonal do tipo zircon destes compostos. Utilizamos correlaÃÃes com outras publicaÃÃes para fazer a designaÃÃo dos modos observados. Notamos que as frequÃncias dos modos internos do tetraedro AsO4 aumenta a medida que nÃmero atÃmico do elemento RE aumenta. Este aumento parece estar relacionado com a diminuiÃÃo das distÃncias das ligaÃÃes RE â O. Entretanto, esta diminuiÃÃo nÃo foi observada de maneira marcante para os modos de baixa frequÃncia. Para a sÃrie RE2 (MoO4)3 (RE = Sm, Eu, Gd and Tb), observamos que os espectros Raman exibem menos modos do que aqueles previstos pela anÃlise de teoria de grupos. Devido à sobreposiÃÃo das bandas, conseguimos designar com certeza apenas os modos n1 e n3 do tetraedro MoO4. Observamos que as vibraÃÃes dos tetraedros II e III sÃo degenerados. A frequÃncia dos modos n1e n3 aumentam ligeiramente quando o elemento RE varia de Sm atà Tb, e isto deve estar relacionado com a contraÃÃo da cÃlula ortorrÃmbica. TambÃm registramos os espectros Raman dos compostos REGd((MoO4)3) (RE = Sm, Er e Tb). NÃo foram observadas alteraÃÃes significativas nos espectros Raman. No entanto, quando Mo à parcialmente substituÃdo por W, um modo de alta freqÃÃncia adicional aparece no espectro de Raman. / The Raman spectroscopy technique was used to investigate the room-temperature phonon characteristics of two series of single crystals containing rare-earth elements: (i) the rare-eartharsenates (REAsO4), RE=Sm, Eu, Gd, Tb, Dy, Ho, Tm, Yb, and Lu) and (ii) the rare-earth molybdates (RE2(MoO4)3). For the REAsO4(RE=Sm, Eu, Gd, Tb, Dy, Ho, Tm, Yb, and Lu)series the Raman data were interpreted in a systematic manner based on the known tetragonal zircon structure of these compounds, and assignments and correlations were made for the observed bands. We found that the wavenumbers of the internal modes of the AsO4 tetrahedron increased with increasing atomic number. This increase seems to be correlated to the contraction of the REâO bond length. For three out of four lattice wavenumbers observed, this tendency was not nearly so marked as in the case of the internal mode wavenumber. For the RE2(MoO4)3(RE = Sm, Eu, Gd and Tb) series the Raman spectra exhibit fewer bands than those predicted by the group theory analysis. Due to the large band overlap, correct assignment was given only to the n1 and n3 modes of the MoO4tetrahedra. We observe that the vibrations from tetrahedra II and III are degenerated. The slightly increase of the frequency of the modes n1 and n3 as RE goes from Sm to Tb is likely to be related to the contraction of the orthorhombic cell. We also recorded the Raman spectra of REGd((MoO4)3) (RE = Sm, Er and Tb). No changes were observed. However, when Mo is partially substituted by W, an extra high-frequency mode appears in the Raman spectrum.

Made available in DSpace on 2014-10-09T12:26:39Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:22Z (GMT). No. of bitstreams: 0 / Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia) / IPEN/D-MPLO / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP; Faculdade de Odontologia, Universidade de Sao Paulo, Sao Paulo

Made available in DSpace on 2014-10-09T12:26:39Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:22Z (GMT). No. of bitstreams: 0 / Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia) / IPEN/D-MPLO / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP; Faculdade de Odontologia, Universidade de Sao Paulo, Sao Paulo

<p> The magnetic susceptibility of samarium orthophosphate (SmPO4) has been measured over the temperature range from 0.4 to 270°K. A theoretical expression for the susceptibility has been developed assuming a crystal field of cubic symmetry and fitted to the experimental data. </p> / Thesis / Master of Science (MSc)

No description available.

ii SUMMARY This master thesis deals with selectivity assessment of an arsenic sequential extraction procedure for evaluating mobility in mine wastes. A modified sequential extraction procedure was designed on the basis of preliminary tests of extraction efficiency and selectivity for the synthetic As mineral phases (scorodite, amorphous iron arsenate, schwertmannite, goethite, jarosite) and five natural samples (Kaňk, Dlouhá Ves, Giftkies, Roudný) that were previously characterized for As concentration and speciation. The modified sequential extraction has five steps. The first leaching step was performed in nitrogen-purged deionized H2O for 10 hours; next step involved 0.01M NH4H2PO4 leaching for 16 hours. Phases in the third step were dissolved with 0.2M Tamm`s reagent in darkness for 2 hours. The fourth step was represented by 0.2M of Tamm`s reagent heated in water bath at 80řC for 4 hours. Strong acid solutions HCl/KClO3/HNO3 were used to leach sulphide phases in the last step. The testing of the sequential extraction procedure using model mixtures showed a good discrimination of several fractions: adsorbed arsenic, arsenic associated with poorly crystalline oxyhydroxide, hydroxosulfate and arsenate phases (amorphous iron arsenate, schwertmannite, ferrihydrite), arsenic associated with crystalline...

Submitted by Alexandre Sousa (alexandre.sousa@incqs.fiocruz.br) on 2015-04-07T12:09:12Z No. of bitstreams: 1 Dissertação_Serodio.pdf: 586656 bytes, checksum: 807186c9c0240e06062add7281e114c6 (MD5) / Approved for entry into archive by Alexandre Sousa (alexandre.sousa@incqs.fiocruz.br) on 2015-04-07T12:09:28Z (GMT) No. of bitstreams: 1 Dissertação_Serodio.pdf: 586656 bytes, checksum: 807186c9c0240e06062add7281e114c6 (MD5) / Approved for entry into archive by Alexandre Sousa (alexandre.sousa@incqs.fiocruz.br) on 2015-04-07T12:09:39Z (GMT) No. of bitstreams: 1 Dissertação_Serodio.pdf: 586656 bytes, checksum: 807186c9c0240e06062add7281e114c6 (MD5) / Made available in DSpace on 2015-04-07T12:09:39Z (GMT). No. of bitstreams: 1 Dissertação_Serodio.pdf: 586656 bytes, checksum: 807186c9c0240e06062add7281e114c6 (MD5) Previous issue date: 2014 / Fundação Oswaldo Cruz. Instituto Nacional de Controle de Qualidade em Saúde / A ampla diversidade do uso dos agrotóxicos pode causar danos ambientais e à saúde humana que muitas vezes, são irreversíveis, ou cujas ações mitigatórias podem ser econômicas, políticas ou socialmente inviáveis. Segundo a Organização Mundial da Saúde, os agrotóxicos são potencialmente tóxicos para outros organismos, incluindo seres humanos, portanto necessitam que sejam descartados apropriadamente e utilizados de maneira segura. Os agrotóxicos são avaliados previamente à produção, à exportação, à importação, à comercialização e ao uso sendo por lei, obrigatório o registro desses produtos com a avaliação dos órgãos federais responsáveis pelos setores de saúde, meio ambiente e agricultura. Tal avaliação visa identificar potenciais danos pelo uso dessas substâncias, com o objetivo de estabelecer proibições, restrições e recomendações para o uso de agrotóxicos, prevenindo e dimensionando os perigos à saúde humana e meio ambiente. A proibição de agrotóxicos que provoquem tais danos deve ser feita a partir de informações dos achados científicos e sua relevância para a exposição humana. A relevância dos estudos experimentais que utilizam sistemas in vitro ou in vivo, se dá a partir da elucidação dos modos de ação tóxica do agrotóxico. O presente trabalho teve como objetivo a reavaliação toxicológica do ingrediente ativo metano arseniato ácido monossódico (MSMA) através de um levantamento bibliográfico criterioso. O intuito é o banimento do MSMA visto que ele quando é metabolizado no solo se biotransforma em espécies arsenicais extremamente tóxicas. Estudos demonstraram que os metabólitos do MSMA que são: As V,As III, MMA e DMAque causam efeitos carcinogênico, teratogênico entre outros que são proibitivos ao seu uso. Este trabalho priorizou os achados mais relevantes para a saúde pública visando o risco do uso de um agrotóxico que causa efeito deletério. / The wide diversity of the use of pesticides can damage the environment and human health, which often are irreversible or whose mitigating actions can be economic, political or socially unviable. According to the World Health Organization, pesticides are potentially toxic to other organisms, including humans, and therefore need to be safely used and properly disposed. Pesticides are evaluated prior to its production, export, import, marketing and use having by law its required registration assessed by the federal agencies responsible for the health, environment and agriculture. This evaluation aims to identify potential damage due to the use of these substances, establishing prohibitions, restrictions and recommendations for their use, preventing and measuring the dangers to human health and the environment. The banishment of pesticides that cause such damage should be basedon information from scientific findings and their relevance to human exposure. The importance of experimental studies using in vitro systems or in vivo, anchors in the elucidation of toxic action mechanisms of pesticides. The present study aimed a toxicological re-evaluation of the active ingredient monosodium methane arsenate acid (MSMA) through a careful literature survey and its official ban, since it is metabolized when the soil biotransforms in extremely toxic arsenic species. Studies have shown that the metabolites of MSMA: AsV, AsIII, MMA and DMA cause carcinogenic, teratogenic and others effects that make their use prohibitive. This work prioritized the most relevant findings for public health about the risk of using a pesticide that causes deleterious effect.