A pirólise de aerossóis ou spray pirólise (SP, do inglês Spray Pyrolysis) é uma importante metodologia para a obtenção de luminóforos e diferentes matrizes sólidas em dimensões nano a micrométricas, desde a escala laboratorial ao nível industrial. O arranjo experimental permite o ajuste de uma ampla faixa das temperaturas de pirólise (100 a 1000 °C), possibilitando que sistemas de interesse sejam obtidos em uma única etapa. Contudo, não existe um controle eficiente do ambiente de coordenação do íon emissor e a simetria deste será consequência do ambiente imposto pela estrutura cristalina ou amorfa da matriz sólida final. O tratamento térmico rápido, característico desta metodologia, pode dificultar a total cristalização de determinadas fases e, sendo assim, uma heterogeneidade nos sítios de simetria será obtida. Este trabalho tem como objetivos estudar as propriedades luminescentes de aluminatos dopados com íons terras raras. E nesse sentido, propuseram-se inicialmente metodologias para a obtenção de diferentes matrizes inorgânicas por SP visando o estudo do sítio de coordenação de íons lantanídeos. Num primeiro momento, foi proposto a metodologia para a obtenção de matrizes inorgânicas por SP mantendo a estrutura do sítio de coordenação de íons lantanídeos. Nesta estratégia foi escolhido um meio inorgânico estável, protegendo os íons terras raras ativos de perturbações externas, estável tanto do ponto de vista químico e térmico durante o processo de pirólise, YVO4:Eu3+ foi o escolhido por possuir sítios de simetria bem definidos e por ser um composto de grande interesse tecnológico. Ainda dentro dos objetivos, estudou a síntese de aluminatos dopados com íons ítrio visando à formação de sistemas compósitos (-Al2O3 / YAG). Os compostos foram primeiro obtidos pela co-dopagem com íons Eu3+ visando um estudo estrutural, e posteriormente, sistemas contendo Itérbio/Érbio e Itérbio/Túlio foram preparados, visto que são escassos os trabalhos que descrevem a síntese de partículas com propriedades de conversão ascendente de energia pela metodologia de pirólise de aerossol. A fase YAG foi obtida para diferentes proporções de Y3+/Al3+, porém também foi obtido a fase meta estável YAlO3 (YAH) em uma única etapa, sendo que essa fase é reportada na literatura como de difícil obtenção. Os compostos obtidos foram caracterizados principalmente por espectroscopia de fotoluminescência (espectros de emissão/excitação e tempos de vida), espectroscopia vibracional, Difratometria de raios X de pó, microscopia eletrônica e análise térmica / Spray Pyrolysis (SP) is an important methodology to obtain phosphors and different solid matrices in a nano-to-micrometric dimension, ranging from the laboratory scale up to the industrial level. The experimental arrangement allows the adjustment of a wide range of pyrolysis temperatures (100 up to 1000 ° C), which allows the system of interest obtention in a single step. However, there is no efficient control concerning the emitter ion coordination environment, and its symmetry will be a consequence of the environment imposed by the resultant solid matrix crystalline or amorphous structure. The rapid thermal treatment, which is the main characteristic of this methodology, it might hinder the total crystallization of certain phases and, thus, heterogeneity in the symmetry sites will be obtained. This study aims to study the luminescent properties of aluminates doped with Rare Earth (RE) ions. Under this perspective, several methodologies have been initially proposed in order to obtain different inorganic matrices using SP to study lanthanides coordination sites. At first, the methodology for obtaining inorganic matrices through SP maintaining the structure of the lanthanide ion coordination site was proposed. In this strategy, a stable (both chemically and thermally) inorganic medium was chosen, protecting the active rare earth ions from external perturbations during the pyrolysis process. YVO4:Eu3+ was selected for presenting well-defined symmetry sites and for its wide technological appeal. Moreover, the synthesis of aluminates doped with yttrium ions to form composite systems (-Al2O3 / YAG) has been carried out. The compounds were first obtained by co-doping with Eu3+ ions for a structural study. Subsequently systems containing Ytterbium / Erbium and Ytterbium / Yttrium were prepared, since there is a lack of description of these systems in the literature when its considered the synthesis of particles with energy upward conversion properties by aerosol pyrolysis methodology. The YAG phase was obtained using different proportions of Y3+/Al3+, but the stable YAlO3 (YAH) phase was also attained in a single step, even being reported as difficult to achieve in the literature. The compounds synthesized were characterized mainly by photoluminescence spectroscopy (emission/excitation spectra and lifetimes), vibrational spectroscopy, powder X-ray diffraction, electron microscopy and thermal analysis

Complexos contendo íons de terras raras são de grande interesse na fabricação de dispositivos eletroluminescentes como é o caso do diodo emissor de luz construído com compostos orgânicos (OLED). Esses dispositivos, utilizando íons de terras raras trivalentes (TR3+) como centros emissores, exibem alta luminescência com bandas espectrais extremamente finas devido à estrutura dos seus níveis de energia, tempos de vida longos e a alta eficiência quântica. Este trabalho relata a preparação de complexos de β-dicetonatos (tta - tenoiltrifluoroacetonato e acac - acetilacetonato) de terras raras (Tb3+, Eu3+ e Gd3+) contendo ligante macrocíclico éter coroa (DB18C6 - dibenzo18coroa6) e de filmes poliméricos de UO22+. Os materiais obtidos foram caracterizados por titulação complexométrica com EDTA, análise elementar de CH, espectroscopia de absorção na região do infravermelho, análise termogravimétrica, difratometria de raios X (método do pó) e espectroscopia de luminescência. Na manufatura do dispositivo OLED construído neste trabalho utilizou-se a técnica de deposição física de filmes finos por fase vapor (PVD, Physical Vapor Deposition). / Complexes containing Rare Earth ions are of great interest in the manufacture of electroluminescent devices as organic light emitting devices (OLED). These devices, using rare earth trivalent ions (TR3+) as emitting centers, show high luminescence with extremely fine spectral bands due to the structure of their energy levels, long life time and high quantum efficiency. This work reports the preparation of Rare Earth β-diketonate complexes (Tb3+, Eu3+, Gd3+) and (tta - tenoyltrifluoroacetonate and acac - acetylacetonate) containing a ligand macrocyclic crown ether (DB18C6 - dibenzo18coroa6) and polymer films of UO22+. The materials were characterized by complexometric titration with EDTA, CH elemental analysis, near infrared absorption spectroscopy, thermal analysis, X-ray diffraction (powder method) and luminescence spectroscopy. For manufacturing the OLED it was used the technique of deposition of thin films by physical vapor (PVD, Physical Vapor Deposition).

Este trabalho apresenta um estudo sobre a influência de nanopartículas de prata nas propriedades ópticas de vidros de telureto dopados com íons de terras raras para aplicações em fotônica. Foram estudados três sistemas vítreos diferentes, TeO2-ZnO (B1), TeO2-PbO-GeO2 (T1) e TeO2-GeO2-BaO-Nb2O5 (Q3), todos preparados com óxidos de Itérbio (Yb2O3), Praseodímio (Pr2O3) e Érbio (Er2O3), além do reagente Nitrato de Prata (AgNO3), precursor das nanopartículas. Estes vidros possuem uma larga região de transmissão (350-6500 nm), boa estabilidade química, resistências mecânica e térmica, baixa energia de fônon (em torno de 700 cm-1) e alto índice de refração (~ 2,0). Através de medidas de absorção óptica foi observada a incorporação dos íons de terras-raras na forma trivalente, responsável pelo fenômeno de luminescência nos vidros. Para comprovar a presença das nanopartículas foram realizadas análises de Microscopia Eletrônica de Transmissão. As análises de microscopia eletrônica de transmissão permitiram observar o tamanho e o formato das nanopartículas formadas. A composição das nanopartículas foi obtida através da técnica de difração de elétrons realizada durante os ensaios de microscopia eletrônica de transmissão. As nanopartículas obtidas nos sistemas vítreos estudados apresentaram-se na forma metálica e cristalina, com tamanho médio variando entre 3 nm e 12 nm. Para o sistema B1 preparado com Yb2O3 foram feitas as medidas da luminescência cooperativa das amostras vítreas e de fibras nanoestruturadas, e estudada a interferência das nanopartículas. Para os sistemas preparados com Pr2O3 e AgNO3 e com Er2O3 e AgNO3 foram estudadas as interferências das nanopartículas nas emissões. Os resultados mais relevantes foram obtidos para o sistema T1, preparado com Pr2O3, para o qual foi observado aumento significativo da intensidade de emissão, de aproximadamente 100 %, na presença das nanopartículas quando comparadas as amostras tratadas por 1 h e 17 h. A diminuição da luminescência, observada em algumas amostras, é atribuída ao fato de as nanopartículas estarem situadas, em relação aos íons de terras-raras, a distâncias inferiores a 5 nm. Os resultados obtidos demonstram que as emissões de íons de terras-raras mais afetadas são as que se encontram mais próximas da banda de absorção do plasmon das nanopartículas. / This work presents a study about the influence of silver nanoparticles in the optical properties of tellurite glasses doped with rare-earths ions for photonic applications. Three different glassy systems were study, TeO2-ZnO (B1), TeO2-PbOGeO2 (T1) and TeO2-GeO2-BaO-Nb2O5 (Q3), all of them prepared with Ytterbium (Yb2O3), Praseodymium (Pr2O3) and Erbium (Er2O3) oxides, and the Silver Nitrate reagent (AgNO3), the nanoparticles precursor. These glasses have a large transmission window (350-6500 nm), chemical stability, mechanical and thermal resistance, low phonon energy (around 700 cm-1) and high refractive index (~2,0). The optical absorption measurement showed the incorporation of rareearths ions in the trivalent form, responsible for the luminescence phenomenon in the glasses. In order to prove the presence of nanoparticles, analyses of Transmission Electron Microscopy (TEM) were performed. These analyses allowed the observation of the size and of the shape of the formed nanoparticles. The composition of the nanoparticles was obtained by the electron diffraction technique performed during the transmission electron microscopy analyses. The nanoparticles obtained in the studied glassy systems presented themselves in metallic and crystalline form, with average size varying between 3 nm and 12 nm. For the B1 system doped with Yb2O3, the cooperative luminescence analyses from the glassy samples and the nanostructured fiber glasses were performed, and the interference of the nanoparticles was studied. For the systems doped with Pr2O3 and AgNO3 and with Er2O3 and AgNO3, it was studied the interference of the nanoparticles on the emissions. The most relevant results were obtained for the T1 system, prepared with Pr2O3, which presented significant enhancement of luminescence, nearly 100 %, in the presence of nanoparticles when compared to the samples heat treated for 1 h and 17 h. The decrease of the luminescence, observed for some samples, is attributed to the fact that the distance between the nanoparticles and the rare-earth ions is smaller than 5 nm. The results obtained show that the rare-earth emissions, that are more influenced, are those whose wavelengths are nearer of the plasmon resonance band of the nanoparticles.

Accelerated soil erosion and the subsequent decline in soil depth has negative environmental, and consequently financial, impacts that have implications across all land cover classifications and scales of land management. Ironically, although attempts to quantify soil erosion nationally have illustrated that soil erosion can occur in the UK, understanding whether or not the UK has a soil erosion problem still remains a question to be answered. Accurately quantifying rates of soil erosion requires capturing both the volumetric nature of the visible, fluvial pathways and the subtle nature of the less-visible, diffuse pathways, across varying spatial and temporal scales. Accordingly, as we move towards a national-scale understanding of soil erosion in the UK, this thesis aims to explore some of the multiple techniques available for developing an understanding of soil erosion in the UK. The thesis first explored the information content of existing UK-based soil erosion studies, ascertaining the extent to which these existing data and methodological approaches can be used to develop an empirically derived understanding of soil erosion in the UK. The second research chapter then assessed which of two proximal sensing technologies, Terrestrial Laser Scanning and Structure-from-Motion Multi-view Stereo (SfM-MVS), is best suited to a cost-effective, replicable and robust assessment of soil erosion within a laboratory environment. The final research chapter built on these findings, using both Rare Earth Oxide tracers and SfM-MVS to elucidate retrospective information about sediment sources under changing soil erosion conditions, also within a laboratory environment Given the biased nature of the soil erosion story presented within the existing soil erosion research in the UK, it is impossible to ascertain if the frequency and magnitude of soil erosion events in the UK are problematic. However, this study has also identified that without ‘true’ observations of soil loss i.e. collection of sediment leaving known plot areas, proxies, such as the novel techniques presented in the experimental work herein and the methods used in the existing landscape scale assessments of soil erosion as included in the database chapter, are not capable of providing a complete assessment of soil erosion rates. However, this work has indicated that despite this limitation, each technique can present valuable information on the complex and spatially variable nature of soil erosion and associated processes, across different observational environments and scales.

Elektron 43 (WE43C) is a modern magnesium rare earth alloy (Mg-RE) with potential light-weighting applications in wrought civil aerospace components. Rare earth elements are known to improve mechanical properties and weaken texture of wrought Mg-RE alloys, but for Elektron 43 the parameters of thermomechanical processing (TMP) that produce optimum microstructure development are not well understood. A large data-set of Elektron 43 flow stress data was collected in an extensive range of hot compression tests at typical TMP temperatures (350-500°C) and strain rates (0.001-100\s). Friction parameters were determined in a ring compression study. Material data was corrected for friction, strain rate and temperature variations. Parameters were fit for a sinh constitutive equation. The corrected material data and used to develop an initial finite element model in the commercial software package QForm. Further work to calibrate the heat transfer parameters is required. The effect of two extrusion parameters (temperature and ram speed) on microstructure and mechanical properties was explored. Extrusion of 60 mm diameter Elektron 43 billets to 20 mm diameter rods (ER=9.92) was conducted at three temperatures (380°C, 420°C and 460°C) and a range of ram speeds (~0.1-15 mm/s). An approximate extrusion limit diagram was formed from empirical relations for extrusion load and hot cracking. Extruded microstructures were bi-modal consisting of dynamically recrystallised (DRX) grains and elongated deformed grains. The typical `prismatic' deformation texture (extrusion direction ED||) was weakened by increasing DRX fraction, concomitant of increased ram speed and temperature. Small DRX grains at low temperature/ram speed had very weak preferences for the 'RE component' with ED||. Increase in ram speed/temperature resulted in a rarely reported 'c-axis' RX texture (ED||) becoming increasingly prominent. This texture dominated at high temperatures and speeds. C-axis grains were larger than those of the RE and prismatic orientations, with the relative difference increasing with DRX fraction. Thus a growth advantage of c-axis grains has been demonstrated: it is postulated these grain boundaries have higher boundary mobility (considering the 90° misoreintation with the deformation texture) and driving pressure (as they are not well oriented for basal slip). Suppression of all RE texture modification followed extrusion at 460°C, 0.16 mm/s. The RX texture was typical of non-RE Mg alloys: ED||. It is argued that at this condition solute segregation is suppressed. Extrusions showed low ambient yield asymmetry. The highest measured yield stresses were correlated with partial RX. These two observations can be explained by a balance of texture, Hall-Petch strengthening and work hardening. One unexplained observation of note is that the maximum observed yields generally correspond to a reversed yield asymmetry.

by Kui Chi Fai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references. / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstracts --- p.ii / Table of Contents --- p.v / Abbreviations --- p.viii / Chapter CHAPTER 1. --- METALLATION OF AMINOPYRIDINE AND AMINOQUINOLINE / Chapter 1.1 --- INTRODUCTION --- p.1 / Chapter 1.1.1 --- General Background --- p.1 / Chapter 1.1.2 --- A Brief Review on Sodium and Potassium Amides --- p.3 / Chapter 1.1.3 --- Preparation of Sodium and Potassium Amides --- p.8 / Chapter 1.2 --- RESULTS AND DISCUSSION --- p.10 / Chapter 1.2.1 --- "Synthesis of [NH(SiButMe2)(R)] [ R = 2-C5H3N-6-Me, 8-C9H6N ] as Ligand Precursors" --- p.10 / Chapter 1.2.2 --- Synthesis of Sodium and Potassium Amido Complexes Containing the Pyridine-Functionalized Amido Ligand [N(SiButMe2)(2-C5H3N-6-Me)]- --- p.11 / Chapter 1.2.2.1 --- Sodium Pyridyl Amido Complexes --- p.11 / Chapter 1.2.2.2 --- Potassium Pyridyl Amido Complexes --- p.12 / Chapter 1.2.3 --- Synthesis of Sodium and Potassium Amido Complexes Containing the Quinoline-Functionalized Amido Ligand [N(SiButMe2)(8-C9H6N)]- --- p.15 / Chapter 1.2.3.1 --- Sodium Quinolyl Amido Complexes --- p.15 / Chapter 1.2.3.2 --- Potassium Quinolyl Amido Complexes --- p.16 / Chapter 1.2.4 --- Physical Characterization of Compounds 3-9 --- p.17 / Chapter 1.2.5 --- "Molecular Structures of Compounds 3, 5 and 7" --- p.20 / Chapter 1.3 --- EXPERIMENTALS FOR CHAPTER 1 --- p.30 / Chapter 1.3 --- REFERENCES FOR CHAPTER 1 --- p.36 / Chapter CHAPTER 2. --- "Synthesis,Structures, and Catalytic Properties of Lanthanide Metal Amides Containing the Pyridine - Functionalized Amido Ligand [N(SiButMe2)(2-C5H3N-6-Me)]-" / Chapter 2.1 --- INTRODUCTION --- p.39 / Chapter 2.1.1 --- General Background --- p.39 / Chapter 2.1.2 --- A Brief Review on Rare Earth Amido Complexes --- p.40 / Chapter 2.1.3 --- General Preparation Methods to Lanthanide Metal Amides --- p.44 / Chapter 2.1.4 --- Ring-Opening Polymerization of Lactones --- p.45 / Chapter 2.1.5 --- Objectives of This Work --- p.48 / Chapter 2.2 --- RESULTS AND DISCUSSION --- p.49 / Chapter 2.2.1 --- Synthesis and Physical Properties --- p.49 / Chapter 2.2.1.1 --- Homoleptic Lanthanide Metal Amides 10-18 --- p.49 / Chapter 2.2.1.2 --- Heteroleptic Lanthanide Metal Amides 19-22 --- p.53 / Chapter 2.2.2 --- Molecular Structures --- p.56 / Chapter 2.2.2.1 --- Molecular Structures of Homoleptic Lanthanide Metal Amides 10-18 --- p.56 / Chapter 2.2.2.2 --- Molecular Structures of Heteroleptic Lanthanide Metal Amides 19-22..… --- p.76 / Chapter 2.2.3 --- Reactivity Studies --- p.89 / Chapter 2.2.3.1 --- "Reaction with 3,5-di-tert-butylcatechol (dbcH2)" --- p.89 / Chapter 2.2.3.2 --- Ring-Opening Polymerization of s-Caprolactone --- p.95 / Chapter 2.3 --- EXPERIMENTALS FOR CHAPTER 2 --- p.100 / Chapter 2.4 --- REFERENCES FOR CHAPTER 2 --- p.108 / Chapter CHAPTER 3. --- Preparation of Pyridine Adducts of Zinc(II) Chloride and Low-coordinate Zinc(II) Dithiolate and Bis(aryloxide) Compounds / Chapter 3.1 --- INTRODUCTION --- p.111 / Chapter 3.1.1 --- General Background --- p.111 / Chapter 3.2 --- RESULTS AND DISCUSSION --- p.115 / Chapter 3.2.1 --- Synthesis of Pyridine Adducts of Zinc(II) Chloride --- p.115 / Chapter 3.2.2 --- Synthesis of Novel Three-Coordinate Zinc(II) Dithiolate and Bis(aryloxide) --- p.116 / Chapter 3.2.3 --- Physical Characterization of Compounds 23-26 --- p.118 / Chapter 3.2.4 --- Molecular Structures of Compounds 23-25 --- p.122 / Chapter 3.3 --- EXPERIMENTALS FOR CHAPTER 3 --- p.129 / Chapter 3.4 --- REFERENCES FOR CHAPTER 3 --- p.133 / Chapter CHAPTER 4. --- Summary of this Research Work --- p.135 / Appendix 1 General Procedures and Physical Measurements --- p.137 / "Appendix 2 Table A-l. Selected Crystallographic Data for Compounds 3, 5，7，10 and 11" --- p.139 / Table A-2. Selected Crystallographic Data for Compounds12-16 --- p.140 / Table A-3. Selected Crystallographic Data for Compounds17-21 --- p.141 / Table A-4. Selected Crystallographic Data for Compounds22-25 --- p.142

Neste trabalho foi estudado as ligas La0,7-xMgx Pr0,3Al0,3Mn0,4Co0,5Ni3,8 (x = 0 a 0,7) como eletrodo negativo de baterias de níquel - hidreto metálico. A hidrogenação das ligas foi realizada com duas pressões de H2 (2 bar e 10 bar) e temperaturas (ambiente e 500°C). A capacidade de descarga das ba terias de níquel hidreto metálico foram analisadas pelo equipamento de testes elétricos ARBIN BT-4. As ligas, no estado bruto de fusão, foram analisadas por microscopia eletrônica de varredura (MEV), espectroscopia de energia dispersiva (EDS) e difração de Raios-X. Com o aumento da concentração de Mg nas ligas aumenta-se a capacidade de descarga, porém nota-se a diminuição a estabilidade cíclica das baterias. A capacidade de descarga máxima obtida foi para a liga Mg0,7Pr0,3Al0,3Mn0,4Co0,5Ni3,8 (60 mAh) e a bateria que apresentou a melhor performance foi La0,4Mg0,3Pr0,3Al0,3Mn0,4Co0,5Ni3,8 (53 mAh e 150 ciclos). A capacidade de absorção de hidrogênio diminui quando se adiciona Mg, não ocorrendo tal efeito para a liga Mg0,7Pr0,3Al0,3Mn0,4Co0,5Ni3,8. / In this work were studied of La0.7-xMgx Pr0.3Al0.3Mn0.4Co0.5Ni3.8 (x = 0 and 0.7) alloys for negative electrodes of the nickel-metal hydride batteries. The hydrogenation of the alloys was performed varying pressing of H2 (2 and 10 bar) and temperature (room and 500°C). The discharge capacity of the nic kel-metal hydride batteries were analyzed in ARBIN BT- 4 electrical test equipment. The as-cast alloys were analyzed by scanning electron microscopy (SEM), energy disperse spectroscopy (EDX) and X-Ray diffraction. The increasing Mg addition in the alloy increases maximum discharge capacity but decrease cycle life of the batteries. The maximum discharge capacity was obtained with the Mg0.7Pr0.3Al0.3Mn0.4Co0.5Ni3.8 alloy (60 mAh) and the battery which presented the best performance was La0.4Mg0.3Pr0.3Al0.3Mn0.4Co0.5Ni3.8 alloy (53 mAh and 150 cycles). The H2 capability of absorption was diminished for increased Mg addition and no such effect occurs for Mg0.7Pr0.3Al0.3Mn0.4Co0.5Ni3.8 alloy.

Submitted by FRANCISCO XAVIER DE CAMPOS null (franciscoxc1@hotmail.com) on 2017-03-01T22:20:44Z No. of bitstreams: 1 Tese_Francisco_Versão Final.pdf: 6434767 bytes, checksum: 1bd6138a771979437fdd6c3bb6d33b68 (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-03-07T17:39:41Z (GMT) No. of bitstreams: 1 campos_fx_dr_araiq.pdf: 6434767 bytes, checksum: 1bd6138a771979437fdd6c3bb6d33b68 (MD5) / Made available in DSpace on 2017-03-07T17:39:41Z (GMT). No. of bitstreams: 1 campos_fx_dr_araiq.pdf: 6434767 bytes, checksum: 1bd6138a771979437fdd6c3bb6d33b68 (MD5) Previous issue date: 2017-02-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Foram sintetizados os compostos Ln(Mef)3, sendo que Ln representa os lantanídeos trivalentes (La ao Lu e o ítrio (Y) e o Mef representa o mefenamato (C15H14NO2-). Os compostos foram sintetizados por adição de solução de mefenamato de sódio sobre solução dos cloretos de lantanídeos e ítrio, sob agitação e aquecimento, e consequentemente foi feita a filtragem, lavagem e secagem dos compostos. A caracterização dos compostos no estado sólido, foi realizada utilizando as técnicas de difratometria de raios X pelo método do pó, complexometria, espectroscopia de absorção na região do infravermelho com transformada de Fourier (FTIR) e pelas técnicas termoanalíticas: termogravimetria e calorimetria exploratória diferencial simultâneas (TG-DSC), e análise dos gases desprendidos (EGA) por espectroscopia de absorção na região do infravermelho com transformada de Fourier (EGA: TG-FTIR). Os resultados forneceram informações sobre o comportamento térmico, estequiometria dos compostos estudados, cristalinidade, sítios de coordenação e também foi possível identificar os principais produtos gasosos desprendidos durante o aquecimento. / The Ln(Mef)3 compounds, where Ln represents the trivalent lanthanides (La to Lu) and yttrium (Y), and Mef represents mefenamate (C15H14NO2 -), were synthesized. The synthesis was perfomed by addition of sodium mefenamate solution to the lathanides and yttrium chloride solutions, with stirring and heating, and the compounds were filtered, washed and dried. The characterization of the compounds in the solid state was carried out using the techniques of X-ray diffraction powder pattern, complexometry, infrared spectroscopy (FTIR) and by thermoanalytical techniques: simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC), and evolved gas analysis (EGA) by infrared spectroscopy (EGA: TG-FTIR). The results provided information on the thermal behavior of the studied compounds as stoichiometry, crystallinity and coordination sites. It was also possible to identify the main gaseous products evolved during the heating.

O complexo estuarino-lagunar de Cananéia-Iguape, localizado na porção sul do litoral do Estado de São Paulo, integra uma importante reserva ambiental e um ecossistema costeiro extremamente produtivo. A região abriga o canal do Valo Grande, construído há mais de 160 anos, o qual favorece a introdução água doce do rio Ribeira de Iguape diretamente no sistema estuarino contribuindo à importantes alterações biogeoquímicas como o aporte de nutrientes, metais e outros elementos pouco solúveis, que acabam tendo como destino os sedimentos. No presente trabalho foi realizada a coleta de amostras da coluna de água e de sedimentos de superfície ao longo do complexo estuarino-lagunar de Cananéia-Iguape e ambientes contíguos. Também houve a realização de perfis de sedimento na região sul do estuário, considerada mais preservada. O objetivo principal foi avaliar os processos que regem a distribuição dos Elementos Terras Raras (ETR) nos sedimentos do sistema, conhecendo as propriedades hidroquímicas do sistema, associando e comparando os ETR a outros elementos presentes em baixas concentrações, de modo natural ou resultantes de alterações de origem antrópica, utilizando padrões de fracionamento, anomalias e assinatura geoquímica de minerais que atuam na distribuição dos ETR verificando seu potencial para evidenciar a origem e interpretar níveis naturais e efeitos antrópicos aos quais o Complexo está submetido. Os resultados mostraram que as características hidroquímicas na região norte do Complexo encontram-se fortemente influenciadas pelo aporte de águas fluviais via Valo Grande e pelos processos biogeoquímicos associados a ele, enquanto a região sul apresentou-se mais conservada, mostrando equilíbrio biogeoquímico natural de sistemas estuarinos, oferecendo maior suporte à produção primária. Nos sedimentos de superfície, as concentrações elementares de Al, As, Ba, Ca, Cd, Co, Cr, Cs, Fe, Hg, Hf, P, Pb, Rb, Sb, Sc, Th, U, Zn, Zr e ETR* apresentaram distribuição bastante relacionada às características deposicionais/texturais, de forma que a maioria destes elementos tiveram maiores concentrações em regiões de baixa energia hidrodinâmica, no interior do rio Ribeira de Iguape e no mar Pequeno. Considerando como referência os valores guias de qualidade dos sedimentos canadenses (TEL e PEL), os elementos As, Cd, Pb, Cr, Hg e Zn apresentaram concentração abaixo dos valores que indicam frequente ocorrência de efeitos adversos nos organismos aquáticos (PEL), mas foi observado que em alguns locais, As, Cr, Pb e Zn superaram os valores de concentração que indicam uma baixa probabilidade de ocorrência de efeitos adversos à biota (TEL). Fatores de enriquecimento calculados com relação à crosta continental superior (FEUCC) e ao background geoquímico regional (FEBG) apontaram regiões onde ocorrem concentrações de Pb, P e Sb acima dos níveis considerados naturais, entretanto evidenciaram que os altos valores de As e Cr estariam relacionados a um enriquecimento natural dos sedimentos na região. No caso dos ETR, o FEUCC e FEBG indicaram enriquecimento na região do mar adjacente ao estuário e em estações no rio Ribeira e no Valo Grande. A aplicação de modelagem através da regressão múltipla linear mostrou que os valores, que seriam normalmente considerados anômalos, são naturais e refletem a presença de minerais pesados nestes locais. Outros elementos que parecem naturalmente enriquecidos onde há ocorrência minerais pesados são: As, Ca, Cr, Th, U, além dos elementos ditos sinalizadores, como Hf e Zr. Anomalias de Ce mostraram a possível relação com processos de oxidação de Ce+3 a Ce+4 mediada biológicamente nas zonas mais produtivas do estuário. Dos quatro perfis de sedimento obtidos na região sul do estuário, três mostraram seções com valores de FEUCC e FEBG para Pb que sugerem contribuição antrópica. Tais padrões decrescem em direção ao sul do sistema, porém praticamente não mostram variação temporal. Nenhuma concentração de Pb superou o valor de TEL nos testemunhos estudados. Zn e Hg mostraram enriquecimentos pontuais em diferentes seções do testemunho T3. Com relação aos ETR, houve novamente a observação de enriquecimento causado por minerais pesados, e os teores modelados parecem refletir níveis naturais para estes elementos nos quatro testemunhos. Tais informações podem ser utilizadas na ampliação do uso de ferramentas biogeoquímicas de avaliação e prevenção de riscos aos quais o sistema estudado está sujeito, e na tomada de decisão pelo poder público no sentido da conservação ambiental da região. / The estuary-lagoon complex of Cananéia-Iguape, in the southern portion of the coast of São Paulo state, is part of an important environmental reserve and an extremely productive coastal ecosystem. The region encloses the Valo Grande channel, built more than 160 years ago, which favors the introduction of fresh water from Ribeira de Iguape river directly into the estuarine system contributing to important biogeochemical changes in the region. Through this channel, many nutrients arrive at the estuary, as well as, metals and other slightly soluble elements, that end up as sediments. In this research, samples of the water column and surface sediments were collected in the estuary-lagoon complex of Cananéia-Iguape and contiguous environments, as well as, sediment profiles in the south of the estuary, considered to be the most conserved region. The main objective of this study was to evaluate the processes that govern the distribution of rare earth elements (REE) in the sediments of the system, associating and comparing them to other elements, both essential and toxic, using fractionation patterns, anomalies and the geochemical signature of minerals that act in the distribution of REE to evaluate the origin and interpret natural levels and the amplitude of possible anthropic effects to which the Complex is submitted. The results show that the hydrochemical characteristics in the northern region of the complex are strongly influenced by the provision of fresh water through Valo Grande channel and its resulting biogeochemical processes, while the southern region is more conserved, showing the natural biogeochemical balance of estuarine systems, offering greater support to primary production. The elemental concentrations of Al, As, Ba, Ca, Cd, Co, Cr, Cs, Fe, Hg, Hf, P, Pb, Rb, Sb, Sc, Th, U, Zn, Zr and REE* in the surface sediments, show distribution related to depositional/textural characteristics, in such a way most of these elements presented their highest concentrations in regions of recognized low hydrodynamic energy, in the Ribeira de Iguape river and Mar Pequeno region. A comparison of the values obtained for As, Cd, Pb, Cr, Hg and Zn with the Canadian sediment quality guidelines (TEL and PEL) shows that none of the evaluated elements reached concentrations indicating a frequent occurrence of negative effects on aquatic organisms (PEL), however, As, Cr, Pb and Zn have sometimes exceeded concentration values indicating a low probability of occurrence of adverse effects on biota (TEL). Enrichment factors calculated in relation to the upper continental crust (FEUCC) and the regional geochemical background (FEBG) pointed out regions where Pb, P and Sb accumulated above the levels considered natural, however have shown that the high values of As and Cr are related to a natural enrichment of the sediments in the region. For the REE, FEUCC and FEBG indicated enrichment in the sea region adjacent to the estuary and at stations in Ribeira de Iguape river and Valo Grande. Data modeling through linear multiple regression showed that the values, which would normally be considered anomalous, are natural and reflect the presence of heavy minerals at these sites. Other elements that appear to be naturally enriched where there is the indication of occurrence of such minerals are As, Ca, Cr, Th, U, in addition to the signaling elements Hf and Zr. Ce anomalies showed a possible relationship with biologically mediated Ce+3 to Ce+4 oxidation processes in the most productive areas of the estuary. Out of the four sediment profiles obtained in the southern region of the estuary, three showed sections with FEUCC and FEBG values for Pb suggesting anthropogenic contribution. Such values decrease towards the south of the system, however showed a small time variation. None of the obtained Pb values overcame the values of TEL for such sediment profiles. Zn and Hg showed one-off enrichments in different sections of T3 sediment core. Regarding REE, there was again the observation of enrichment caused by heavy minerals in one of the sediment cores, and the modeled contents seem to reflect natural levels for these elements in the four cores. Such information can be used in the expansion of the biogeochemical tools for assessment and prevention of the risks to which the studied system is subject and in the decision making by the public sector towards the environmental preservation of the region.

O objetivo principal deste trabalho foi identificar e separar os níveis de energia dos multipletos excitado, 4S3/2, e fundamental, 4I15/2, provenientes do íon Er3+ alojado nos vários sítios não equivalentes existentes no garnet Ca3Ga2Ge3O12. Várias técnicas de espectroscopia óptica (absorção, luminescência com bombeio seletivo, excitação e conversão ascendente de luz) foram usadas com este objetivo. A partir dos resultados experimentais foram calculados, pela primeira vez, os parâmetros de íon livre e de campo cristalino para o Er3+ em cada um dos sítios identificados. Experimentos de luminescência e absorção sob a influência de campo magnético também foram realizados, e o fator g tanto do estado 4S3/2 quanto do 4I15/2 do Er3+ neste garnet foram determinados. / The main objective of this work was to identify and attribute the energy levels of excited 4S3/2 and ground 4I15/2states, corresponding to the Er3+ ions located at the various non equivalent sites present in the Ca3Ga2Ge3O12 garnet. Several optical spectroscopic techniques, (absorption, site-selective luminescence, excitation and upconversion of light), were used with this objective. From the experimental results, it was possible, for the first time, to calculate the free ion parameters, as well as the crystalline field parameters, for the Er3+ ions in each of the identified sites. Luminescence experiments and absorption under the influence of the magnetic field were performed, and the g factor associated to both, 4S3/2 and 4I15/2 estates in this garnet were determined.