A produção de fundidos com baixo nível de defeitos e com propriedades mecânicas adequadas é facilmente alcançada com a previsão do comportamento do metal durante a solidificação. A transferência de calor entre o metal-líquido e o molde, nos primeiros instantes de contato, compromete definitivamente as propriedades mecânicas e a qualidade do produto final. O comportamento da transferência de calor entre o metal e o molde foi explorado através da análise térmica experimental e confrontado com o Modelo de Schwarz Modificado (MSM). Para comprovar experimentalmente os fenômenos previstos no MSM tais como: superesfriamento aparente, posição das interfaces líquido-superaquecido/líquido- superesfriado e da sólido/líquido durante a solidificação foram realizados experimentos com alumínio puro, gálio puro e estanho. Para a análise térmica foram utilizados dois sistemas de solidificação vertical descendente (Griffiths et al., 1993; Jinho et al., 1996; Jamgotchian et al., 1987). O sistema A e o sistema B, sendo que o sistema B também permitia a solidificação vertical ascendente. Em ambos os casos, o fluxo de calor foi direcionado através de uma barra de alumínio (na temperatura ambiente) que foi inserida verticalmente no banho (técnica do “dedo frio”). A barra extrai calor do líquido em função da diferença de temperatura entre a massa líquida e a massa sólida e simula o choque térmico do metal líquido com as paredes de um molde. Os resultados experimentais e os obtidos pela simulação foram confrontados. Apresenta-se a relação experimental entre o superesfriamento e a taxa de solidificação. Discute-se o redimensionamento da Ti (temperatura de interface) na solução de Schwarz e a comprovação experimental da solução do MSM. / The production of casting with low level of defects and adjusted mechanical properties can be obtained with the previous knowledge of the metal solidification behavior. The transference of heat between the metal-liquid and the mold, in the first instants of the contact, compromises definitively the mechanical properties and the final product quality. The behavior of the transference of heat between the metal and the mold was carried out through the experimental thermal analysis and the results were compared with the Modified Schwarz Model (MSM). To experimentally prove, the cooled phenomena in the MSM such as: apparent supercooling, liquid superheated/liquid supercooled interfaces position and of the liquid/solid during the solidification experiments had been carried out with pure aluminum, pure gallium and tins. Two systems A and B, one of descending vertical solidification and another one of descending and ascending solidification, had been used for the thermal analysis. In both systems, the heat flow was directed through a bar of aluminum (in the ambient temperature) that was inserted vertically in the bath (“cold finger” technique). The bar extracts heat of the liquid, had the difference of temperature between the liquid mass and the solid mass, and simulates the thermal shock of the metal with the mold walls. The experimental results were compared with simulated data. In this work are presented experimental relation between the supercooling and the rate of solidification. The new dimension of the Ti (temperature of interface) in the Schwarz equation and the experimental evidence of MSM solution, are considered.

The objective of this study is to investigate the accuracy and computational efficiency of two commonly used formulations for performing the geometrically nonlinear thermal analysis of plane framed structures. The formulations considered are the followings: the Beam-Column formulation and the updated Lagrangian version of the finite element formulation that has been adopted in the commercially well-known software SAP2000. These two formulations are used to generate extensive numerical data for three plane frame configurations, which are then compared to evaluate the performance of the two formulations. The Beam-Column method is based on an Eulerian formulation that incorporates the effects of large joint displacements. In addition, local member force-deformation relationships are based on the Beam-Column approach that includes the axial strain, flexural bowing, and thermal strain. The other formulation, the SAP2000, is based on the updated Lagrangian finite element formulation. The results for nonlinear thermal responses were generated for three plane structures by these formulations. Then, the data were compared for accuracy of deflection responses and for computational efficiency of the Newton-Raphson iteration cycles required for the thermal analysis. The results of this study indicate that the Beam-Column method is quite efficient and powerful for the thermal analysis of plane frames since the method is based on the exact solution of the differential equations. In comparison to the SAP2000 software, the Beam-Column method requires fewer iteration cycles and fewer elements per natural member, even when the structures are subjected to significant curvature effects and to restrained support conditions. The accuracy of the SAP2000 generally depends on the number of steps and/or the number of elements per natural member (especially four or more elements per member may be needed when structure member encounters a significant curvature effect). Succinctly, the Beam-Column formulation requires considerably fewer elements per member, fewer iteration cycles, and less time for thermal analysis than the SAP2000 when the structures are subjected to significant bending effects.

AN ABSTRACT OF THE THESIS OF Sujan Shrestha, for the Master of Science degree in Civil Engineering, presented on March 3, 2015, at Southern Illinois University, Carbondale. TITLE: POST BUCKLING RESPONSE OF SWAY COLUMNS UNDER MECHANICAL AND THERMAL (FIRE) LOADS MAJOR PROFESSOR: Dr. Aslam Kassimali, Ph.D. The post-buckling response of sway columns under mechanical and thermal loadings are presented by using the geometrical nonlinear analysis. For thermal analysis, the columns are assumed to be fully restrained in their axial directions. The method of analysis uses Beam-Column theory which is based on an Eulerian (corotational) formulation. Numerical solutions are shown for the post-buckling response of sway columns. The numerical investigations of the geometrically nonlinear analysis of sway columns were carried out with three different boundary conditions of sway columns as suggested by AISC, under mechanical loading and temperature changes. The sway columns considered are the cases `c', `e' and `f' in Table C-A-7.1 of AISC Manual (2011). These were modeled and analyzed to predict the post-buckling response under the mechanical and thermal loads. Furthermore, for each of these support conditions, the effects of slenderness ratios on the post-buckling response were analyzed by considering the slenderness ratios of 50,125 and 200. Also, the effects on post-buckling strength were observed keeping the same slenderness ratios but varying rotational end conditions of sway columns. Many useful conclusions can be drawn from this study. The more important conclusions are: 1) As all unrestrained sway columns undergo excessive deformation under mechanical loading, they do not possess significant post-buckling strength once the loading reaches the buckling load. 2) All restrained sway columns undergo much smaller deformations under thermal loading as compared to mechanical loading; thus significant post-buckling strength is achieved even after reaching the buckling temperature. This post-buckling strength can be considered during the design of structures which will aid in safe and economical structures. 3) Slenderness ratios play an important role on post-buckling strength only in thermal analysis but not in mechanical analysis. Increase in slenderness ratio tends to decrease the post-buckling relative deformation of the columns under thermal loading but has no such effect under mechanical loading. 4) Rotational end conditions also play significant role on post-buckling strength during thermal analysis but not during mechanical analysis. Keeping the slenderness ratio constant and varying the rotational end conditions, the post-buckling strength of all sway columns remains same under mechanical loading but is different under thermal loading.

SENA JÚNIOR, Diniz Maciel de. Propriedades Vibracionais e Térmicas do Topiramato Cristalino. 2008. 129 f. Tese (Doutorado em Física) - Programa de Pós-Graduação em Física, Departamento de Física, Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2008. / Submitted by Edvander Pires (edvanderpires@gmail.com) on 2015-05-04T19:42:01Z No. of bitstreams: 1 2008_tese_dmsenajunior.pdf: 1941905 bytes, checksum: cd866cd3390085e83129c5851eaff4d6 (MD5) / Approved for entry into archive by Edvander Pires(edvanderpires@gmail.com) on 2015-05-07T16:55:19Z (GMT) No. of bitstreams: 1 2008_tese_dmsenajunior.pdf: 1941905 bytes, checksum: cd866cd3390085e83129c5851eaff4d6 (MD5) / Made available in DSpace on 2015-05-07T16:55:19Z (GMT). No. of bitstreams: 1 2008_tese_dmsenajunior.pdf: 1941905 bytes, checksum: cd866cd3390085e83129c5851eaff4d6 (MD5) Previous issue date: 2008 / The scientific interest on molecular crystals stems from their great versatility and ease of processing. For pharmaceutically active ingredients, the structure-activity relationship is of major importance. Topiramate, a white and crystalline solid, is a powerful drug efficiently employed to control epilepsy symptoms. The mechanism of action involves a negative modulatory effect on the AMPA/kainate subtypes of glutamate receptors and some types of voltage-gated Na+ and Ca2+ channels, and a positive modulatory effect on some types of GABAA receptors and at least one type of K+ channels in neurons. Despite its pharmacological attributes, the lack of publications regarding its physical-chemical properties in the literature is apparent. In order to fill this gap, a research comprising vibrational spectroscopy techniques (Raman and infrared), thermal analysis (TGA/DTA/DSC), and theoretical calculations, was carried out. With the aid of calculations employing density functional theory (DFT), most of the observed vibrational bands is assigned. Consideration of Raman spectra recorded at temperatures above and below room temperature, as well as under high hydrostatic pressures, indicated maintenance of the orthorhombic crystalline structure under the diverse thermodynamic conditions employed. Thermal analysis, however, showed that, after the melting point, the sample undergoes decomposition in a process comprising three stages, possibly initiated with loss of the sulfamate group by the molecule. This event inspired a theoretical study aimed at promoting the sulfamate group bond breakage in a controlled way by employing a laser instead of heat. This was accomplished by quantum dynamics simulations which showed that, by using a set of ultrashort pulses in the infrared region, it is possible to reach levels close to 70 % dissociation in less than 3 ps. / O interesse científico pelos cristais moleculares resulta da facilidade de processamento destes materiais, e de sua grande versatilidade. No caso de drogas, a relação entre estrutura e atividade é de suma importância. Topiramato, um sólido branco e cristalino, é um fármaco utilizado com bastante eficiência para controlar os sintomas da epilepsia. O mecanismo de ação envolve um efeito modulatório negativo nos receptores de glutamato do subtipo AMPA/kainato e alguns tipos de canais de Na+ e Ca2+ voltagem-dependentes, bem como um efeito modulatório positivo em alguns tipos de receptores GABAA e pelo menos um tipo de canal de K+ nos neurônios. A despeito de suas qualidades farmacológicas, a escassez de trabalhos relacionados às suas propriedades físico-químicas na literatura é evidente. Para ajudar a preencher esta lacuna, uma investigação envolvendo técnicas de espectroscopia vibracional (Raman e infravermelho), análises térmicas (TGA/DTA/DSC), e cálculos teóricos, foi realizada. Com a ajuda de cálculos empregando a teoria do funcional de densidade (DFT), a atribuição da maioria das bandas vibracionais observadas foi realizada. A observação dos espectros Raman obtidos em temperaturas acima e abaixo da ambiente, bem como sob altas pressões hidrostáticas, indicou que a estrutura cristalina ortorrômbica é mantida nas diferentes condições termodinâmicas empregadas. A análise térmica, entretanto, mostrou que, após a fusão, o material sofre decomposição em um processo que envolve três etapas, possivelmente iniciado com a perda do grupo sulfamato pela molécula. Este fato motivou um estudo teórico a fim de modelar a quebra da ligação do sulfamato de maneira controlada, utilizando um laser em lugar de calor. Isto foi realizado com simulações de dinâmica quântica, que mostraram que, através da utilização de uma combinação de pulsos ultracurtos na região do infravermelho, é possível atingir níveis próximos a 70% de dissociação em menos de 3 ps.

This thesis investigates the broad subject of thermal management problems currently encountered in Formula One race car design. A computationally economical tool, based on linear superposition, for predicting the temperature field arising from a set of thermal and inlet velocity boundary conditions was developed. Using a set of base analyses, the research showed that it is possible to superpose and scale these results in order to predict the temperature field for differing sets of boundary conditions. This method was shown to have a significant speed advantage over typical computational simulations. An experimental facility was designed and built to provide validation for aspects of the linear superposition approach. A method of measuring the cylinder wall heat flux has been developed using thin film gauge technology. The resulting sensor was designed to fit the mounting of existing instrumentation in order to avoid requiring large scale modifications to existing test facilities. The design makes use of modern rapid prototyping techniques in order to meet this mounting requirement and to provide a novel solution to routing the signal from the thin film gauge. In addition, the research investigated a method for predicting the cylinder wall temperature in real-time. The cylinder wall is subject to heat fluxes from in-cylinder gases during the engine cycle on the inner face and the effect of the coolant jacket on the outer face. Two separate methods were used to process these thermal boundary conditions respectively, before being superposed in order to form the whole solution. The computation time of the method is characterised in order to demonstrate its feasibility for real-time operation.

Made available in DSpace on 2014-06-11T19:25:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-27Bitstream added on 2014-06-13T19:32:46Z : No. of bitstreams: 1 costa_fb_me_ilha.pdf: 9510999 bytes, checksum: 9a5d3acde99bb0f41fcb579520ce6a76 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Os vidros preparados para diversas aplicações têm um ponto em comum: a possibilidade de nuclear e cristalizar novas fases, quando preparados a partir de uma massa fundida ou através de um tratamento térmico acima da temperatura de transição vítrea. Neste trabalho são apresentadas de forma sucinta as formulações teóricas de formação de vidros incidindo principalmente nos processos de nucleação e crescimento de fases. O estudo da cristalização de vidros pode ser feito através de métodos cinéticos baseados na descrição teórica formulada por Johnson-Mehl- Avrami (JMA). Estes métodos descrevem os processos de nucleação e cristalização utilizando dados provenientes das curvas de DTA/DSC. Uma delas é aquela proposta por Kurajica, que determina os parâmetros cinéticos utilizando um modelo para a resolução da sobreposição dos picos de cristalização. Para a aplicação deste modelo, foram utilizados vidros teluretos, de composição 80TeO2 - 10Nb2O5 - 8Li2O - 2V2O5 (mol%) denominados TNLV, e vidros fosfatos, de composição 50P2O5 - 36Na2O - 10CdO - 4La2O3 (mol%), dopados com 20 e 60mg de CeO2 denominados PNCL20 e PNCL60. O estudo cinético teve início com a identificação das fases cristalinas formadas, utilizando a difratometria de raios X (DRX). Considerando a formação de três fases cristalinas para cada sistema vítreo, a equação proposta por Kurajica foi aplicada, utilizando o software Origin 7.0, para determinação dos parâmetros cinéticos, a partir dos ajustes dos dados de DSC. Os coeficientes de Avrami (n) determinados mostraram que para o sistema TNLV o crescimento se dá em três dimensões com mecanismos diferentes, enquanto que para os sistemas PNCL20 e PNCL60, o crescimento ocorre em três dimensões com reação de interface. Foi observado que... / The glasses prepared for various applications have one common point: the possibility of new phases nucleation and crystallization, when prepared from a melt or through a heat treatment above the glass transition temperature. In this work are presented briefly the theoretical formulations of formation of glass focusing mainly in the processes of phases nucleation and growth. The study of glass crystallization can be done by kinetic methods based on the theoretical description formulated by Johnson- Mehl-Avrami (JMA). These methods describe the processes of nucleation and crystallization using data from DTA/DSC curves. One model is that proposed by Kurajica which determine the kinetic parameters resolving overlapping peaks of crystallization. To apply this model were used a tellurite glass, with composition 80TeO2 - 10Nb2O5 - 8Li2O - 2V2O5 (mol%) denominated TNLV, and two phosphate glasses of composition 50P2O5 - 36Na2O - 10CdO - 4La2O3 (mol%) doped with 20 and 60mg of CeO2 denominated PNCL20 and PNCL60. The kinetic study started us with the identification of crystalline phase, using the X-ray diffraction (XRD). Considering that three crystalline phases are formed for each glassy system, the Kurajica equation was applied using the Origin 7.0 software, for determining the kinetic parameters. The calculated Avrami coefficients (n) shown that for the TNLV system the growth occurs in three dimensions with different mechanisms, while for the PNCL20 and PNCL60 systems the growth occurs in three dimensions with an interface reaction. It was observed that the PNCL20 system has higher activation energy that the PNCL60 system and XRD patterns showed that the characteristic peaks of the phases containing CeO2, become higher and thinner in the system PNCL60. These results show that the cerium may favors the glass crystallization.

Made available in DSpace on 2014-06-11T19:32:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-02-28Bitstream added on 2014-06-13T18:43:10Z : No. of bitstreams: 1 carvalho_tm_dr_araiq.pdf: 2738200 bytes, checksum: 7e03a4b975a3e46138463fcb45b37a6d (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Neste trabalho foi analisado o efeito de adições de 4, 6, 8 e 10% de Ag (m/m) na cinética não-isotérmica da reação eutetóide em ligas de Cu-Al contendo 9, 10 e 11%Al (m/m), utilizando-se calorimetria exploratória diferencial (DSC), microscopia óptica (MO), microscopia eletrônica de varredura (MEV) e difração de raios X (DRX). Foram considerados dois caminhos reacionais distintos, um partindo das ligas inicialmente submetidas a recozimento e outro das ligas inicialmente submetidas a têmpera. Os resultados indicaram que os valores da energia de ativação (Ea) obtidos para a reação eutetóide reversa pelos métodos de Kissinger e de Ozawa foram bastante semelhantes. Para as ligas submetidas a têmpera, os valores de Ea obtidos foram maiores do que para as ligas inicialmente recozidas. Esse aumento no valor da energia de ativação deve estar relacionado com o caminho de reação de formação da fase β a partir da fase complexa (α+g1). Para as amostras submetidas a recozimento prolongado o caminho reacional segue uma seqüência de transformações mais simples (a+a2) ® (a+g1) ® b e para as amostras submetidas a têmpera o caminho reacional é mais complexo, b’ (ou b’1) ® b1 ® (a+g1) ® b. As adições de Ag, em ligas do sistema Cu-Al, interferem nos valores da energia de ativação da reação eutetóide reversa. As alterações dos valores de energia de ativação podem também ser atribuídas às mudanças do comportamento do soluto da reação e da solubilidade da prata devido ao aumento do teor de alumínio na composição das ligas. A análise da variação da energia de ativação Ey com a fração transformada (y) na reação (a+g1) ® b, foi feita aplicando-se o método isoconversional (“model-free”). Os resultados mostraram que os valores... / In this work, the effect of additions of 4, 6, 8 and 10wt.% Ag on the nonisothermal kinetics of the eutectoid reaction in alloys of the Cu-Al system containing 9, 10 and 11wt.%Al, was studied using differential scanning calorimetry (DSC), optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffractometry (XRD) and considering two different reaction paths, one starting from annealed and other from quenched alloys. The results indicated that the activation energy values obtained for the reverse eutectoid reaction using the Kissinger and Ozawa methods were very similar. The values obtained for the quenched alloys were higher than those obtained for the annealed alloys. This increase in the activation energy values must be related to the reaction path for the β phase formation from the (a+g1) complex phase. The reaction paths for the β phase formation could be as follows: (a+a2)®(a+g1)®b for annealed alloys and b’(or b’1)®b1®(a+g1)®b for quenched alloys. The results indicated that Ag additions to Cu–Al alloys interfere on the reverse eutectoid reaction. The changes in the activation energy were attributed to changes in the reaction solute and in Ag solubility due to the increase in Al concentration. The isoconversional method was used to obtain a variation of the activation energy Ey with y, the conversion factor, for the (a+g1)®b reverse eutectoid reaction. The results showed that the activation energy for the reaction changes with Al concentration and strongly depends on the reaction path. The conversion dependence of the activation energy indicates a complex process comprising consecutive... (Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:35:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-22Bitstream added on 2014-06-13T19:24:24Z : No. of bitstreams: 1 carvalho_ct_dr_araiq.pdf: 783523 bytes, checksum: 845f90e2b52f8926bba04e0f2219f870 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Sintetizou-se o ácido 2-metoxicinamalpirúvico (2-MeO-HCP), através da reação de condensação aldólica do 2-metoxicinamaldeído (CH3O-C6H4-(CH)2-CHO), 96 % de pureza com o piruvato de sódio, (Na-2-MeO-CP), 99% puro, ambos da Aldrich. A pureza do ácido 2-metoxicinamalpirúvico sintetizado foi determinada por DSC através do pico de fusão em 125 ºC. O ácido 2-metoxicinamalpirúvico foi convertido a uma solução de aproximadamente 0,15 mol L-1 de 2-metoxicinamalpiruvato de sódio (pH~7,5). Com esse sal foram sintetizados os compostos no estado sólido (Ln-2-MeO-CP.nH2O), sendo que Ln representa os lantanídeos trivalentes e Y(III), 2-MeO-CP o ligante 2-metoxicinamalpiruvato e n o número de moléculas de água com n = 1,5 para o composto de túlio e itérbio e para os demais compostos n = 1. Os Ln-2-MeO-CP.nH2O foram obtidos no estado sólido por adição lenta do ligante aos respectivos cloretos metálicos ou nitratos sob agitação contínua até a total precipitação dos íons metálicos. Os precipitados foram filtrados em papel de filtro Whatman n 42 lavando-se os mesmos com água destilada até a obtenção de teste negativo para cloretos com AgNO3 em meio nítrico e difenilamina para nitratos. Posteriormente os precipitados foram secos em temperatura ambiente e armazenados em dessecador contendo cloreto de cálcio. Técnicas instrumentais utilizadas no estudo dos compostos: Termogravimetria e Análise Térmica Diferencial Simultânea (TG-DTA) e Calorimetria Exploratória Diferencial (DSC) e Complexometria com EDTA (padrão de 1,000 x 10-2 mol L-1 ) forneceu informações sobre grau de hidratação, comportamento térmico e estequiometria; Difratometria de Raios X pelo método do pó, informações da cristalinidade e Espectroscopia de Absorção na Região do Infravermelho sugeriu a forma de coordenação dos compostos sintetizados. Na caracterização do ácido... / The 2-methoxycinnamylidenepyruvic acid (2-MeO-HCP) was synthesized through the reaction of aldolic condensation of 2-methoxycinnamaldehyde (CH3O-C6H4-(CH) 2-CHO), 96% purity, with sodium pyruvate, (Na-2 - MeO-CP) 99% pure, both from Aldrich. The purity of 2-methoxycinnamylidenepyruvic synthesized was determined by DSC through the melting peak at 125 ºC. The 2-methoxycinnamylidenepyruvic acid was converted to a solution of about 0.15 mol L-1 of the sodium 2-methoxycinnamylidenepyruvate (pH ~ 7.5). With this salt were synthesized the solid compounds (Ln-2-MeO-CP.nH2O), where Ln represents trivalent lanthanides and Y (III), 2-MeO-CP is the methoxycinnamylidenepyruvate ligand and n the number of water molecules with n = 1.5 for the compound thulium, ytterbium and for the other compounds, n = 1. The Ln-2-MeO-CP.nH2O were obtained in the solid state by slow addition of the ligand to the respective metal chlorides or nitrates on continuous stirring until total precipitation of metal ions. The precipitates were filtered through filter paper Whatman number 42, washing them with distilled water to obtain a negative test for chloride with AgNO3 in nitric acid and diphenylamine to nitrates. Subsequently the precipitates were dried at room temperature and stored in a desiccator containing calcium chloride. Instrumental techniques used in the study of compounds: Thermogravimetry and differential thermal analysis (TG-DTA), Differential Scanning Calorimetry (DSC) and Complexometry with EDTA (standard padrão de 1,000 x 10-2 mol L-1 ) provided information on degree of hydration, thermal behavior and stoichiometry; X-ray Diffractometry by the method of powder provided information about crystallinity, and Absorption Spectroscopy in the Infrared Region suggested the form of coordination of the compounds synthesized. In the characterization of 2-methoxycinnamylidenepyruvic, apart from the DSC... (Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:35:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-02-22Bitstream added on 2014-06-13T20:45:59Z : No. of bitstreams: 1 lima_ls_dr_araiq.pdf: 1748247 bytes, checksum: 80701efb22420181e8d4d0411c29aa85 (MD5) / Foram sintetizados, no estado sólido, os compostos Ln2L3∙nH2O, sendo que Ln representa os lantanídeos trivalentes (La ao Lu) e o ítrio(III) e o L representa o succinato (C4H4O4). Os compostos foram sintetizados por adição estequiométrica, sob agitação, do ligante nas respectivas soluções de cloretos ou nitratos de lantanídeos. A caracterização dos compostos foi realizada utilizando métodos como difratometria de raios X pelo método do pó, análise elementar, complexometria e as técnicas termoanalíticas como termogravimetria e análise térmica diferencial simultânea (TG-DTA), caloria exploratória diferencial (DSC) e termogravimetria acoplada à espectroscopia de absorção na região do infravermelho com transformada de Fourier (TG-FTIR). Os resultados forneceram informações sobre o comportamento térmico, cristalinidade, estequiometria dos compostos estudados. Também foi possível identificar os produtos gasosos liberados durante o aquecimento / Solid-state Ln2L3∙nH2O compounds, where Ln stands for trivalent lanthanides (La to Lu) or yttrium(III) and L is succinate(C4H4O4), have been synthesized. The solid-state compounds were prepared by stoichiometric relation adding slowly, with continuous stirring the ligand solution to the respective metal chloride or nitrate solution. The characterization of the compounds was performed using X-ray powder diffratometry, elemental analysis,complexometry, simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC) and thermogravimetry coupled to absorption spectroscopy in the region of infrared with Fourier transform (TG-FTIR). The results provided information about thermal behaviour, crystallinity, stoichiometry of the compounds studied. It was also possible to identify the gaseous products released during heating

Made available in DSpace on 2014-06-11T19:35:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-11-13Bitstream added on 2014-06-13T19:24:25Z : No. of bitstreams: 1 ionashiro_ey_dr_araiq.pdf: 1019528 bytes, checksum: 4d4e903d3f05bbf9a22a2874ae1638f3 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Os 2-metoxibenzalpiruvatos de lantanídios (III) (exceto promécio) e ítrio (III) foram preparados adicionando-se solução de 2-metoxibenzalpiruvato de sódio na solução aquosa dos seus respectivos cloretos metálicos, exceto o cério, que foi empregado na forma de nitrato. A caracterização dos compostos sintetizados foi realizada utilizando: termogravimetria e análise térmica diferencial simultânea (TG-DTA), Calorimetria Exploratória Diferencial (DSC), espectroscopia de absorção na região do infravermelho, difratometria de raios X pelo método do pó e complexometria com EDTA. Os resultados da complexometria com EDTA e das curvas TG, permitiram inferir sobre a estequiometria dos compostos obtidos. Resultados de TG-DTA e DSC também forneceram informações sobre desidratação, estabilidade e decomposição térmica dos mesmos. Os espectros de absorção na região do infravermelho sugerem que a coordenação metal-ligante ocorre através do carboxilato e carbonila cetônica. Os difratogramas de raios X, pelo método do pó mostraram que os compostos formados não apresentaram reflexões, sugerindo uma estrutura não cristalina, ou microcristalina. / The 2-methoxybenzylidenepyruvate of lanthanides (III) (except promethium) and yttrium (III), were prepared by adding aqueous solution of sodium 2-methoxybenzylidenepyruvate to the solutions of the metal chlorides, expect the cerium that was used as its nitrate. The synthesized compounds were characterized using the simultaneous thermogravimetry and differential thermal analysis (TG-DTA), infrared spectroscopy, X-ray powder diffraction and EDTA complexometry. The results from EDTA complexometry and from TG curves, permitted to establish the stoichiometry of these compounds. The TG-DTA results also permitted to obtain information's about the dehydration, thermal stability and thermal decomposition of these compounds. The infrared spectra suggested that the metal-ligand coordination occurs through the carboxylate and ketonic carbonyl groups. The X-ray powder patterns showed that the obtained compounds do not present a crystalline structure.