Thesis--University of Louisville. / At head of title: Chemical Technology Division. Chemical Development Section B. Includes bibliographical references (p. 55-56).

Thesis (D.Sc. (Chemistry)) - Rhodes University, 2006. / [Appendix]. Dedication - Acknowledgements - Curriculum vitae - Biographical notes - Publication list - Introduction to my research - Commentary-books - Commentary-research papers - Conclusions.

Orientador: Gilbert Bannach / Banca: Egon Schnitzler / Banca: Massao Ionashiro / O Programa de Pós Graduação em Ciência e Tecnologia de Materiais, PosMat, tem caráter institucional e integra as atividades de pesquisa em materiais de diversos campi / Resumo: O comportamento térmico e a caracterização de formas cristalinas dos anti-histamínicos cimetidina, famotidina, ranitidina-HCI e nizatidina foram estudados neste trabalho. As técnicas de calorimetria exploratória diferencial (DSC), termogravimetria e calorimetria exploratória diferencial simultâneas (TG-DSC), difração de raios X (DRX), termomicroscopia de luz Polarizada (PLTM) e espectroscopia de absorção na região do infravermelho com transformada de Fourier (FTIR) foram às técnicas utilizadas para a caracterização dos fármacos e das suas formas recristalizadas. As curvas TG-DSC forneceram informações sobre a estabilidade térmica dos compostos estudados, sendo que a mesma aumenta na seguinte ordem: ranitidina-HCI < famotidina < cimetidina < nizatidina. Essas curvas também demonstraram que os processos de recristalização aumentaram a estabilidade térmica da cimetidina e famotidina, mas diminuíram a estabilidade térmica da nizatidina. As curvas DSC indicaram, através do picos de fusão, que a cimetidina e todas as suas recristalizações possuem uma mesma forma cristalina, ocorrendo o mesmo no caso da nizatidina. Com relação à famotidina, os picos de fusão indicaram que ela pode se apresentar sobre duas estruturas cristalinas distintas entre si. Os experimentos de termomicroscopia confirmaram as informações obtidas a partir das curvas TG-DSC e DSC, em relação à estabilidade térmica e descomposição térmica dos compostos estudados. Esses experimentos também mostraram informações quanto à inversibilidade dos processos térmicos ocorridos durante o aquecimento e resfriamento dos anti-histamínicos estudados. Através do deslocamento das bandas de absorção nos espectros de FTIR e da análise da intensidade e posição dos picos dos difratogramasde pó, foi possível verificar que apenas a famotidina apresentou indícios de ocorrência de polimorfismo / Abstract: The thermal behavior and characterization of crystalline forms of antihistamines, cimetidine, famotidine, nizatidine, and ranitidine-HCI were studied in this work. The techniques of differential scanning calorimetry (DSC), thermogravimetry and differential scanning calorimetry simultaneous (TG-DSC), X-ray diffraction (XRD), polarized light termomicroscopy (PLTM) and Fourier transform infrared spectroscopy (FTIR) were used for the characterization of drugs and their recrystallised forms. The TG-DSC curves provided information on the thermal stability of the compounds studied, and the same increases in the following order: ranitidine-HCI <famotidine <cimetidine <nizatidine. These curves demonstrated that the processes of recrystallization increase the thermal stability of cimetidine and famotidine, but decreased the thermal stability of nizatidine. The DSC curves indicated through the melding peak, that cimetidine and all its recrystallization have the same crystalline form, the same happening in the case of nizatidine. With respect to famotidine, the melting peak indicated that it may present on two different crystal structures between them. The thermomicroscopy experiments confirmed the information obtained from the TG-DSC and DSC curves in relation to the thermal stability and thermal decomposition of the compounds studied. These experiments also revealed information about the irreversibility of the thermal processes occurring during heating and cooling of the antihistamines. Through the shift of the absorption bands in FTIR spectra and analysis of the intensity and position of the peaks of powder diffraction patterns, it was observed that only the famotidine has shown evidence of the occurrence of polymorphism / Mestre

Orientador: Gilbert Bannach / Banca: Daniel Rinaldo / Banca: Egon Schnitzler / Resumo: O processo de fabricação de painéis MDF é muito dinâmico e a todo instante surgem novidades tecnológicas buscando não somente otimizar custos de processo, mas incrementar novas características ou melhorar a resistência mecânica e usinabilidade. As fibras de madeira de eucalipto e as resinas termofixas como a uréia-formaldeído desempenham papel importantíssimo no contexto industrial. Um grande número de pesquisas e estudos se direciona a aperfeiçoar os processos de fabricação por meio do aprimoramento da matéria-prima. Muitos materiais foram desenvolvidos e adicionados tanto as fibras como as resinas sendo muito comum a busca por melhorias na resistência mecânica nas chapas MDF. A resina MDI (metileno difenil diisocianato), por exemplo, possui muitas vantagens conhecidas como a isenção de emissão de formol e a alta resistência a água, porém, outras características relacionadas à interação química com a madeira são pouco estudadas. Nesse contexto tecnológico, o presente trabalho se dedicou ao uso das técnicas termoanalíticas TG/DTG-DTA e DSC para investigar e compreender melhor a interação química entre as fibras de madeira de eucalipto e as resinas sintéticas termofixas e por fim, sugerir melhorias ao processo produtivo buscando assim, reduzir custos de fabricação. Além das técnicas termogravimétricas, a espectroscopia vibracional de absorção na região infravermelho médio com transformada de Fourier também foi usada para auxiliar na proposta reacional de polimerização e princi... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The process of manufacturing MDF panels is very dynamic and at every moment technological innovations are emerging, seeking not only to optimize process costs, but to increase new characteristics or improve mechanical strength and machinability. Eucalyptus wood fibers and thermoset resins such as urea-formaldehyde play a very important role in the industrial context. A great number of researches and studies are directed at perfecting the manufacturing processes through the improvement of the raw material. Many materials have been developed and added to both fibers and resins, and the search for improvements in mechanical strength in MDF sheets is very common. MDI resin (methylene diphenyl diisocyanate), for example, has many advantages known as formaldehyde emission exemption and high water resistance, but other characteristics related to the chemical interaction with wood are little studied. In this technological context, the present work was dedicated to the use of TG / DTG-DTA and DSC thermoanalytical techniques to investigate and better understand the chemical interaction between eucalyptus wood fibers and thermosetting synthetic resins and, finally, to suggest improvements to the production process thus seeking to reduce manufacturing costs. In addition to the thermogravimetric techniques, the vibrational absorption spectroscopy in the medium infrared region with Fourier transform was also used to aid in the polymerization reaction proposal and mainly in the identificati... (Complete abstract click electronic access below) / Mestre

I have chosen the title for this thesis, "Reactions in the Solid State", for two reasons: Firstly, it is broad enough to cover all of my areas of research, which have been: • Effects of irradiation on solids (PhD topic) • Silver refining (while at the Chamber of Mines) • Kinetics of decomposition of solids (with Dr A.K. Galwey and various others) • Techniques of thermal analysis • Pyrotechnic delay systems (with support from AECI Explosives) • Thermal and photostability of drugs (with Prof B.D. Glass) and, secondly, it was the title of the very successful book co-authored by Drs Andrew Galwey, David Dollimore and me. A large part of my research has been involved in the writing and editing of books, so these are covered in a separate commentary, while commentary on the more than 100 papers to which I have contributed forms the main part of this compilation. It is hoped that the electronic format will enable ready access of to all aspects of my research, including electronic versions of the original papers. The reader will need a copy of Adobe Acrobat Reader to access these.

Made available in DSpace on 2014-06-11T19:29:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-01-19Bitstream added on 2014-06-13T18:38:43Z : No. of bitstreams: 1 turquetti_jr_me_araiq.pdf: 2440105 bytes, checksum: 350f9c996d550c9b871c4348d00295eb (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Técnicas de análise térmica (TG-DTA), eletroquímica (voltametria cíclica) e de análise de superfície (Microanálise por EDX, mapeamento dos elementos, obtenção das imagens SEM e XRD) foram empregadas para o estudo das reações em estado sólido da liga de composição Pt-Rh15% e Hg. A partir das técnicas de VC e TG-DTA, foi possível ESTUDAR O SISTEMA Pt-Rh15%-Hg e, com o emprego da análise de superfície, evidenciar o ataque efetivo do Hg sobre o substrato, e ainda, a formação de compostos de caráter covalente, compostos do tipo: PtHg, PtHg2, RhHg2 e PtHg4, caracterizados através da técnica de XRD. As técnicas de análise de superfície, permitiram, ainda, revelar a presença de um filme de intermetálicos sobre a superfície do substrato, e uma distribuição homogênea do Hg sobre a superfície. O sistema Pt-Rh15%-Hg apresentou um comportamento térmico (TG) e eletroquímico (VC), similar ao sistema Pt-Rh10%-Hg, diferindo, apenas, quanto à presença do intermetálico PtHg2, visto que para o sistema Pt-Rh10%-Hg, apresenta a formação deste intermetálico, se dá como resultado da decomposição térmica do PtHg4. Quando comparado à liga de Pt-Rh30%, esta, por sua vez, não apresenta a formação do intermetálico PtHg4. Desta forma, o comportamento observado para o sistema Pt-Rh15%-Hg, apresentando reatividade intermediária aos sistemas Pt-Rh10%-Hg e Pt-Rh30%- Hg, é resultado do teor do elemento modificador, Rh, na matriz de Pt. / The thermal analysis (TG-DTA), electrochemistry (CV) and surface analysis (EDX microanalysis, Mapping, SEM and XRD) techniques were used to study solid-state reactions of Pt-Rh15% alloy and Hg. The CV and TG showed an effective Hg attack on the alloy, and the covalent compounds formation as PtHg, PtHg2, RhHg2 and PtHg4, characterized by XRD technique. The surface analysis showed, an intermetallic film on the alloy surface, and the Hg homogeneous distribution on the surface. The Pt-Rh15%-Hg system, showed an electrochemical (VC) and thermal (TG) behavior, similar to Pt-Rh10%-Hg, but, the Pt-Rh10%-Hg system, presents the PtHg2 formation as result of thermal PtHg4 decomposition. The Pt-Rh15% alloy, presents, a considerable Hg attack in comparison with the Pt-Rh30% alloy, this system, do not present the PtHg4 intermetallic formation. The Pt-Rh15%-Hg behavior, presenting an intermediary reactivity in comparison with Pt-Rh10%-Hg and Pt-Rh30%-Hg system, it is result of the Rh in the Pt matrix.

Made available in DSpace on 2014-06-11T19:30:19Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-12-09Bitstream added on 2014-06-13T19:39:47Z : No. of bitstreams: 1 perpetuo_gl_me_bauru.pdf: 3715637 bytes, checksum: b7318ddf8ea48c5cbde1a7071a8927ed (MD5) / O comportamento térmico e a caracterização de formas cristalinas dos anti-histamínicos cimetidina, famotidina, ranitidina-HCI e nizatidina foram estudados neste trabalho. As técnicas de calorimetria exploratória diferencial (DSC), termogravimetria e calorimetria exploratória diferencial simultâneas (TG-DSC), difração de raios X (DRX), termomicroscopia de luz Polarizada (PLTM) e espectroscopia de absorção na região do infravermelho com transformada de Fourier (FTIR) foram às técnicas utilizadas para a caracterização dos fármacos e das suas formas recristalizadas. As curvas TG-DSC forneceram informações sobre a estabilidade térmica dos compostos estudados, sendo que a mesma aumenta na seguinte ordem: ranitidina-HCI < famotidina < cimetidina < nizatidina. Essas curvas também demonstraram que os processos de recristalização aumentaram a estabilidade térmica da cimetidina e famotidina, mas diminuíram a estabilidade térmica da nizatidina. As curvas DSC indicaram, através do picos de fusão, que a cimetidina e todas as suas recristalizações possuem uma mesma forma cristalina, ocorrendo o mesmo no caso da nizatidina. Com relação à famotidina, os picos de fusão indicaram que ela pode se apresentar sobre duas estruturas cristalinas distintas entre si. Os experimentos de termomicroscopia confirmaram as informações obtidas a partir das curvas TG-DSC e DSC, em relação à estabilidade térmica e descomposição térmica dos compostos estudados. Esses experimentos também mostraram informações quanto à inversibilidade dos processos térmicos ocorridos durante o aquecimento e resfriamento dos anti-histamínicos estudados. Através do deslocamento das bandas de absorção nos espectros de FTIR e da análise da intensidade e posição dos picos dos difratogramasde pó, foi possível verificar que apenas a famotidina apresentou indícios de ocorrência de polimorfismo / The thermal behavior and characterization of crystalline forms of antihistamines, cimetidine, famotidine, nizatidine, and ranitidine-HCI were studied in this work. The techniques of differential scanning calorimetry (DSC), thermogravimetry and differential scanning calorimetry simultaneous (TG-DSC), X-ray diffraction (XRD), polarized light termomicroscopy (PLTM) and Fourier transform infrared spectroscopy (FTIR) were used for the characterization of drugs and their recrystallised forms. The TG-DSC curves provided information on the thermal stability of the compounds studied, and the same increases in the following order: ranitidine-HCI <famotidine <cimetidine <nizatidine. These curves demonstrated that the processes of recrystallization increase the thermal stability of cimetidine and famotidine, but decreased the thermal stability of nizatidine. The DSC curves indicated through the melding peak, that cimetidine and all its recrystallization have the same crystalline form, the same happening in the case of nizatidine. With respect to famotidine, the melting peak indicated that it may present on two different crystal structures between them. The thermomicroscopy experiments confirmed the information obtained from the TG-DSC and DSC curves in relation to the thermal stability and thermal decomposition of the compounds studied. These experiments also revealed information about the irreversibility of the thermal processes occurring during heating and cooling of the antihistamines. Through the shift of the absorption bands in FTIR spectra and analysis of the intensity and position of the peaks of powder diffraction patterns, it was observed that only the famotidine has shown evidence of the occurrence of polymorphism

This work deals with problem of analyzing cooling curves of ductile iron and discovering possibility to predict shrinkage tendency of melt from thermal analysis results. This work was executed in foundry production conditions where obtained data from thermal analysis data linked to experimental castings where amount of shrinkage was estimated. Data were analyzed and looked for correlations between acquired thermal data and shrinkage defects.

No description available.

A study was made of the problem of differential thermal analysis utilizing statistical experimental design. A factorial type of design was chosen to yield maximum efficiency of the data obtained. “Lakeland”, Florida Kaolin of commercial whiteware grade was selected because of its relative purity. Due to the large number of samples to be analyzed, it was found necessary to choose a commercial brand rather than a very pure kaolinite which was found impossible to obtain in sufficient quantity. A statistical 2x3x3 factorial design was used and the calculations incident thereto made in detail. Data, which to the eye appeared erratic, was found to be acceptable within the probability limits of error of the experiment. The effects of two different furnaces, three rates of heating, and three densities of the samples were analyzed to determine the area under the endothermic reaction peaks as measured by Cr-Al differential thermocouples. It was found that densities and rates both yielded highly significant values and that the interactions of the two showed significant results when examined by a distribution of “F”¹. These effects were analyzed for the regressions therein and were found to be significant in the linear trends only. From this indication it would seem evident that the optimum density and rate of heating had not been reached in the limits of this experiment. Replications and furnaces did not yield significant results when tested by “F” distribution. From this it was deduced that the experiment could be conducted with sufficient precision under the present procedure and conditions and reproducibility obtained irrespective of the furnace used. Examination of the data will indicate that the level of the two furnaces is different, but the trends within are in the same areas. A certain amount of erratic data were obtained due to a lag in heating rates and this difficulty will be discussed. / Master of Science