Made available in DSpace on 2014-12-02T11:16:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-06-27Bitstream added on 2014-12-02T11:21:40Z : No. of bitstreams: 1 000800310.pdf: 1457093 bytes, checksum: 30c4f442544d6afe3a329dc9c8491a8e (MD5) / No sistema de semeadura direta (SSD), a prática da correção da acidez do solo se restringe ao uso do calcário, havendo poucas informações em relação às escórias de siderur gia. O trabalho objetivou avaliar as alterações em atributos químico s do solo, absorção de nutrientes e produtividade do feijoeiro, aveia preta e soja em sucessão, em função da aplicação incorporada e superficial de escórias de siderurgia, comparadas ao ca lcário, na implantação do sistema de plantio direto . O experimento foi conduzido sob um Latossolo Vermelho distrófico , durante três anos (2010 - 2013) . Os tratamentos consistiram na aplicação superficial e incorporada de sete corretivos da acidez do solo: es córias de aciar ia (EA), de alto forno (EAF), forno de panela (EFP), do aço inox (agrosilício ® ) ( AG), wollastonita (W), calcário dolomítico (CD) e calcário dolomítico calcinado (CDC), além de uma testemunha sem aplicação de corretivo. A dose aplicada de cad a corretivo foi calculada para elevar a saturação por bases do solo a 70%. Em fevereiro de 2011 foi realizado o primeiro cultivo com o feijoeiro ( Phaseolus vulgaris ) , em seguida o experimento foi desenvolvido obedecendo a um sistema de sucessão de culturas , ou seja, no inverno foi semeada a aveia preta ( Avena strigosa ) e no verão a soja ( Glycine max ). Os corretivos de acidez do solo proporcionaram alterações nos atributos químicos do solo, com elevação nos teores de Ca, Mg, P refletindo em alterações nos va lores de soma de bases, saturação por bases e capacidade de troca catiônica. As escória s forno de panela (EFP), do aço inox (AG) e de aciaria (EA) pode m ser aplicadas em SSD, com eficiência semelhante aos calcários na neutralização da acidez do solo. A mai or solubilidade do silicato em relação ao carbonato não torna as ... / In the no - tillage system, soil acidity correction practice is restricted to limestone use and there is little information regarding the use of steel slag. The study aimed to evaluate the amendments in soil chemical attributes, yield and nutrient u ptake of common bean, soybean and black oat according to the application forms of slags, compared to limestone, in the implantation of no till system. The experiment was conducted under a Rhodic Hapludox for three years (2010 - 2013). The treatments consiste d of surface and incorporated application of seven soil acidity correctives: steel slag (SS), blast furnace slag (BFS), ladle furnace slag (LFS), stainless steel slag (“agrosilício”) (AG), wollastonite (W), lime (L) and calcined dolomite lime (CDL), plus o ne control without corrective application. Each material dose was calculated to raise the base saturation to 70%. In February 2011, the first cultivation of bean ( Phaseolus vulgaris ) occurred. Afterwards, the experiment was developed according to a success ion of cultures, that is, in winter black oats was sown ( Avena strigosa ) and in summer, soybean ( Glycine max ) was sown. Soil acidity correctives materials provided changes in soil chemical properties, increased Ca, Mg, P and values of sum of bases, base saturation and CEC. The ladle furnace slag (LFS), SS and AG can be applied in the no - tillage system with similar efficiency to limestone to neutralize soil acidity. Higher solubility of the silicate in regard to the carbonate neither become the steel slag more efficient than the limes not even correct soil acidity faster at the establishment of no - tillage system. The common bean yield increases by application of correctives in soil acidity, while, black oat yield shows low answer to the correctives material s applications. The agrosilicate (AG), SS, LFL, W, CDL and L increases similarly soy bean yield in the no - tillage system ...

Orientador: Guilherme de Siqueira Ferreira Anzaloni Saavedra / Banca: Renata Marques de Melo Marinho / Banca: Alexandre Luiz Souto Borges / Banca: Tiago Moreira Bastos Campos / Banca: Marcelo Lucchesi Teixeira / Resumo: O objetivo deste trabalho foi avaliar o silicato de lítio reforçado por zircônia quanto a sua microestrutura e as mesmas propriedades mecânicas em diferentes fases de cristalização. Cento e vinte amostras de discos de silicato de lítio reforçado por zircônia foram usinados de acordo com as normas ISO 6872 (12x1,2mm) para o ensaio de flexão biaxial. Foram separados em 4 grupos de acordo com a fase de cristalização. Grupo I: 30 amostras de Celtra pré cristalizado (CNC); Grupo II: 30 amostras de Celtra cristalizado (CC); Grupo III: 30 amostras de Suprinity Não Cristalizado (SNC) e Grupo IV: 30 amostras de Suprinity Cristalizado (SC). Os corpos de prova foram submetidos ao ensaio mecânico de flexão biaxial e em seguida realizadas análises qualitativas e quantitativas. Por meio microscopia eletrônica de varredura, microscopia eletrônica com emissão de campo MEV-FEG, EDS e difração de raios X (n=4), foi realizada a caracterização completa dos materiais e análise morfológica da microestrutura para todos os grupos. Para as análises estatísticas foram utilizados o módulo Weibull (m) e resistência característica (σ0) / Abstract: The objective of this work was to evaluate the lithium silicate reinforced by zirconia as to its microstructure and the same mechanical properties in different phases of crystallization. One hundred and twenty samples of zirconia-reinforced lithium silicate discs were machined according to ISO 6872 (12x1,2mm) standards for the biaxial flexural test. They were separated into 4 groups according to the crystallization step. Group I: 30 samples of Pre-Crystallized Celtra (CPC); Group II: 30 samples of Crystallized Celtra (CC); Group III: 30 samples of Uncrystallized Suprinity (SNC) and Group IV: 30 samples of Crystallized Suprinity (SC). The specimens were submitted to the mechanical biaxial flexion test and qualitative and quantitative analyzes were performed. Scanning Electron Microscopy, Electron Microscopy with Field emission SEM-FEG, EDS and X-ray diffraction (n = 4) were carried out to characterize the materials and morphological analysis of the microstructure for all groups. The Weibull (m) and characteristic resistance (σ0) were used for the statistical analysis / Doutor

Made available in DSpace on 2014-10-09T12:33:36Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:02Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP

Orientador: Leonardo Theodoro Büll / Banca: Rosemary Marques de A. Bertani / Banca: Marcelo Andreotti / Banca: Dirceu Maximino Fernandes / Banca: Carlos Alexandre Costa Crusciol / Resumo: No sistema de semeadura direta (SSD), a prática da correção da acidez do solo se restringe ao uso do calcário, havendo poucas informações em relação às escórias de siderur gia. O trabalho objetivou avaliar as alterações em atributos químico s do solo, absorção de nutrientes e produtividade do feijoeiro, aveia preta e soja em sucessão, em função da aplicação incorporada e superficial de escórias de siderurgia, comparadas ao ca lcário, na implantação do sistema de plantio direto . O experimento foi conduzido sob um Latossolo Vermelho distrófico , durante três anos (2010 - 2013) . Os tratamentos consistiram na aplicação superficial e incorporada de sete corretivos da acidez do solo: es córias de aciar ia (EA), de alto forno (EAF), forno de panela (EFP), do aço inox (agrosilício ® ) ( AG), wollastonita (W), calcário dolomítico (CD) e calcário dolomítico calcinado (CDC), além de uma testemunha sem aplicação de corretivo. A dose aplicada de cad a corretivo foi calculada para elevar a saturação por bases do solo a 70%. Em fevereiro de 2011 foi realizado o primeiro cultivo com o feijoeiro ( Phaseolus vulgaris ) , em seguida o experimento foi desenvolvido obedecendo a um sistema de sucessão de culturas , ou seja, no inverno foi semeada a aveia preta ( Avena strigosa ) e no verão a soja ( Glycine max ). Os corretivos de acidez do solo proporcionaram alterações nos atributos químicos do solo, com elevação nos teores de Ca, Mg, P refletindo em alterações nos va lores de soma de bases, saturação por bases e capacidade de troca catiônica. As escória s forno de panela (EFP), do aço inox (AG) e de aciaria (EA) pode m ser aplicadas em SSD, com eficiência semelhante aos calcários na neutralização da acidez do solo. A mai or solubilidade do silicato em relação ao carbonato não torna as ... / Abstract: In the no - tillage system, soil acidity correction practice is restricted to limestone use and there is little information regarding the use of steel slag. The study aimed to evaluate the amendments in soil chemical attributes, yield and nutrient u ptake of common bean, soybean and black oat according to the application forms of slags, compared to limestone, in the implantation of no till system. The experiment was conducted under a Rhodic Hapludox for three years (2010 - 2013). The treatments consiste d of surface and incorporated application of seven soil acidity correctives: steel slag (SS), blast furnace slag (BFS), ladle furnace slag (LFS), stainless steel slag ("agrosilício") (AG), wollastonite (W), lime (L) and calcined dolomite lime (CDL), plus o ne control without corrective application. Each material dose was calculated to raise the base saturation to 70%. In February 2011, the first cultivation of bean ( Phaseolus vulgaris ) occurred. Afterwards, the experiment was developed according to a success ion of cultures, that is, in winter black oats was sown ( Avena strigosa ) and in summer, soybean ( Glycine max ) was sown. Soil acidity correctives materials provided changes in soil chemical properties, increased Ca, Mg, P and values of sum of bases, base saturation and CEC. The ladle furnace slag (LFS), SS and AG can be applied in the no - tillage system with similar efficiency to limestone to neutralize soil acidity. Higher solubility of the silicate in regard to the carbonate neither become the steel slag more efficient than the limes not even correct soil acidity faster at the establishment of no - tillage system. The common bean yield increases by application of correctives in soil acidity, while, black oat yield shows low answer to the correctives material s applications. The agrosilicate (AG), SS, LFL, W, CDL and L increases similarly soy bean yield in the no - tillage system ... / Doutor

Made available in DSpace on 2014-10-09T12:33:36Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:02Z (GMT). No. of bitstreams: 0 / Os resíduos sólidos galvânicos despertam especial atenção, devido à sua composição tóxica. Tais resíduos geralmente são estocados nas empresas de galvanoplastia, criando um preocupante passivo ambiental, em particular, nas áreas densamente povoadas, como a zona leste da cidade de São Paulo, que, por sua vez, possui um pólo de empresas de galvanoplastia do setor de cromação. Face ao pressuposto, na primeira parte do trabalho, um estudo foi realizado com a compilação dos dados de empresas galvânicas situadas na zona leste de São Paulo, abordando aspectos socioeconômicos e de processo, que influenciam na geração e na destinação dos resíduos sólidos industriais. Na segunda parte do trabalho, amostras selecionadas de resíduos sólidos foram avaliadas quanto às suas características químicas e físico-químicas e foi apresentada a viabilidade do uso tecnológico visando o aproveitamento destes resíduos. Os principais resultados obtidos mostraram que nas dezessete empresas visitadas são geradas 106 toneladas de resíduos sólidos por ano e estes são armazenados em condições precárias, podendo afetar a população vizinha em caso de acidentes ambientais. Os resíduos constituídos majoritariamente por Ni, Cr, B, Cu, Ca, S, C, Na, Fe e Zn, quando aquecidos até 1400°C, apresentaram formações de compostos identificados como Ca2Cr2O5, BaCrO4, NiCr2O4, CuCrO2, CaSO4, Ni2SiO4, NiO e CuO. Estes compostos são difíceis de serem obtidos e, por si só, apresentam potencial para comercialização como matérias-primas para a produção de produtos cerâmicos. Os resíduos sólidos galvânicos foram incorporados em matrizes vítreas, indicando uma alternativa satisfatória e de baixo custo para a inertização dos constituintes nocivos à saúde. Os vidros obtidos apresentaram aspectos coloridos, podendo ser utilizados como produtos finais ou como matérias-primas para a produção de esmaltes cerâmicos ou pigmentos inorgânicos. Existem diversas possibilidades de destinação dos lodos galvânicos e, independente de qual seja adotada, conclui-se que é de extrema importância a sua retirada de dentro das empresas, para eliminar o enorme e crescente passivo ambiental. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP

The present thesis gives a summary of results obtained through theoretical and experimental studies of systems with relevance to copper smelting and converting. Many chemical elements are involved in the copper production pro­cesses and a detailed experimental study would be very time- consuming and expensive. A complicating fact is also the corrosivity of the liquid phases towards container material. A powerful alternative is equilibrium calculations, in which models for the liquid phases as well as reliable basic thermodynamic data are needed. In the present thesis, a generalized structure based model for liquid silicates was developed and used in assessments of the sys­tems PbO-SiO2, Fe-O-SiO2, CuO0.5-SÌO2 and Cu-Fe-O-SiO2. In the model, the non-ideal silicate melt is treated as an ideal solu­tion but containing a few complexes. The PbO-Si02 melt could be described by introducing the complexes Pb3Si207, Pb4Si4010 and Pb13Si12O37 in addition to the components PbO and Pb2Si04. The species considered in the Fe-O-SiO2 melt were FeO, FeO1.5, Fe2Si04, Fe3Si207, Fe3Si6O15 and in the CUO0.5-SiO2 melt CuO0.5 ana CU4SiO4. Trie calculated phase diagrams, the activities of me­tal oxides and the oxygen partial pressures were all in good agreement with the published data. Two of the papers in this thesis concern the determination of Gibbs free energies for Cu2S(s,l) and Ca2Fe2O5(s) through emf measurements utilizing a solid electrolyte. Activities and termi­nal solubilities in the solid solution [Fet,Ca]0 were also deter­mined. The results obtained from the quantitative equilibrium calcula­tions for conventional copper smelting and converting were used to outline the overall reactions taking place and the outcome of changes in process parameters. Comparison with observed values, however, showed that the copper and magnetite contents in slag were calculated too low. These discrepancies could be completely explained by using a non-equilibrium approach in which the con­verter was assumed to consist of several segments with concentra­tion gradients between the segments. / digitalisering@umu.se

Cette thèse traite de la diffusion couplée dans un système verrier industriel contenant quatre oxydes (SiO2, Al2O3, CaO, Na2O). La gamme de températures considérée s’étend de la transition vitreuse (650°C) au liquidus (1200°C). Les premiers résultats concernent la nature macroscopique de la diffusion. La matrice des coefficients de diffusion permet de quantifier la mobilité des composants et met en évidence de nombreuses interactions entre eux. D’autres informations sont obtenues à l’échelle microscopique. Les équations d’échanges synthétisent les principaux chemins de diffusion suivis au sein du système sous la forme de réactions. L’ensemble des données de la littérature est traité et semble converger vers des chemins de diffusion préférentiels. Des hypothèses sur les mécanismes de la diffusion des espèces sont proposées. Les résultats obtenus à basse température permettent de discuter les liens entre propriétés de transport et diffusion. L’étude de la structure du matériau s’est appuyée sur la spectroscopie Raman. Les expériences de diffusion donnent accès à un grand nombre de compositions verrières, permettant ainsi de développer un outil statistique de traitement des spectres. Les composantes spectrales ainsi obtenues sont discutées à la lumière des nombreuses observations décrites dans la littérature. Cette démarche permet également d’interpréter les composantes au travers des corrélations entre leurs intensités relatives et la composition du matériau ainsi qu’en étudiant leur évolution le long des profils de diffusion. La possibilité de faire de la spectroscopie Raman une technique de quantification des espèces est discutée. / This manuscript deals with the coupled diffusion in an industrial glass system containing four oxides (SiO2, Al2O3, CaO, Na2O). The temperature range extends from the glass transition temperature (650°C) to the liquidus (1200°C). The first results concern the macroscopic nature of diffusion. The matrix containing the diffusion coefficients quantifies the mobility of the components and highlights many interactions between them. Other information can be obtained at the microscopic scale. The exchange equations summarize the main diffusion paths followed by the system in reactions form. All the data from the literature are processed and they seem to converge towards preferential diffusion paths. Hypothesis about the mechanisms of diffusion of the species are proposed. The results obtained at low temperatures open a discussion of the relationship between transport properties and diffusion. The study of the structure of the material was based on Raman spectroscopy. Diffusion experiments provide a large number of glass compositions, which allowed us to develop a statistical tool for handling spectra. The spectral components thus obtained are discussed in the light of the many observations described in the literature. This approach allowed us to interpret the components through correlations between their relative intensities and the composition of the material and by studying their evolution along the diffusion profiles. The possibility of a Raman spectroscopy technique for quantifying species is discussed.

The presented study deals with the sol-gel synthesis of nanocrystalline ternary phases of the general formula ZnxTiyOz, their characterization and potential application in photonics. Achieved results brings new fundamental knowledge about the processes leading to the formation of ZnxTiyOz nanocrystals from amorphous xerogels and gives novel information about structural and opto-electrical properties of prepared materials. Based on the presented results, most of all up-to-date reported ZnxTiyOz compounds with tailored nanocrystalline size and structure can be prepared as powders or thin films. Two sol-gel approaches based on the cluster process and direct heteronucleation were employed to prepare initial sol. Sols were optionally doped by Eu3+ ions to evaluate the effects of rare earth element to crystallization properties of formed compounds. In the first part of our study crystallization properties and structural evolution of thermally treated xerogels were analyzed. As a result a versatile method allowing the preparation of inverse spinel Zn2TiO4, cubic defect spinel ZnTiO3 and rhombohedral ZnTiO3 with tailored nanocrystal sizes was established. Initial composition and thermal annealing allow us to prepare selected ternary phase with tailored nanocrystal size ranging from tens of nanometers up to...

No description available.

<P> This thesis is concerned with the investigation of the diffusion controlled reaction between MgO and β-quartz in the temperature range 1200 - 1450 °C in wet and dry atmospheres. The reactions were studied by placing known faces of quartz crystals in direct contact with Mg0 powder, heat treating them, and then investigating the cross sections. The product layer was investigated by both reflected light and thin section metallography, electron - microprobe and X- ray diffraction. Using Wagner's and Schmalzried's ideas on solid state reactions, a theoretical model for the diffusion controlled formation of silicates was developed. With this model, a mechanism for the diffusion controlled formation of forsterite from MgO and β-quartz was advanced. </P> / Thesis / Master of Science (MSc)