Thesis (MTech(Chemical engineering))--Cape Technikon, Cape Town,1996 / Metal cyanide complexes are a toxic pollutant in waslewater originating from various industrial and mining activities. The removal/retrieval ofcyanide and metal cyanide complexes has been studiedby researches for many years, leading to the establishment of a variety of patents. The mechanisms used by these patents vary from purely chemical techniques to those using ion exchange Iesins. In this thesis, ,the feasIbility ofthe recovery ofmetal cyanide complexes by using a strong base macroreticular resin, in a fluidized bed configuration, has been investigated. The resin in question is presently used in the sugar indnstry where its main application is the recovery oflarge organic molecules similar in nature to metal cyanides. The selected resin was contacted with synthetic solntions of various metal cyanide complexes. for the purposes of evaluating performance in the adsorption th..."feOf. It was found that polyvalent metal cyanide molecules were adsOlbed efficiently, while divalent metal cyanide molecules were adsorbed satisfactorily. The loaded resin was also evalnated for the ease with which the metal cyanides conId be removed. It was discovered that a brine solntion ofpH 7, conId effectively remove all metal cyanide complexes. This test-work was of particular importance as it is well !moon that the removal ofmetal cyanides from strong base metals is not easily achieved. To distingnish the fluidization characteristics of the selected resin (or any resin for that matter), a method of modelling the expansion of a flnidized resin bed was proposed, that takes into account the diflicnIties associated with the byclrod:)nantic charncteristics of a macroporous resin of this nature. The technique is based on the Serial Afadel which is a discretised application of the Z3ki and Richardson equation. From the interpretation of the resnIts of a matrix of fluidization tests, it was fonnd that the algorithm proposed conId effectively model the expansion of a fluidized bed of ion exchange resin, independently of the dimensions ofthe accomodatiog receptical. Finally. it was shown that the change in the fluidization characteristics of the selected resin, between its chloride and metal cyanide states, could clearly be modelled by the technique referred to above.

Orientadores: Flavio Henrique Baggio Aguiar, Jose Roberto Lovadino / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-13T11:37:42Z (GMT). No. of bitstreams: 1 Soares_GiullianaPanfiglio_M.pdf: 730604 bytes, checksum: 4496655ec779f61c3be30cc95bf5663a (MD5) Previous issue date: 2009 / Resumo: A manutenção da integridade entre dente e restauração é importante para o sucesso clínico de restaurações adesivas, influenciando a longevidade das mesmas. Assim, o objetivo deste trabalho "in vitro", composto por dois experimentos, foi avaliar a infiltração marginal em cavidades Classe II: 1) confeccionadas com um sistema adesivo e compósito dental, variando a fonte de luz e o tempo de fotoativação do sistema adesivo, submetidos aos testes de ciclagem mecânica e térmica; 2) confeccionadas com um sistema adesivo e um compósito dental, variando a fonte de luz e o tempo de fotoativação da resina composta, submetidos ou não aos testes de ciclagem mecânica e térmica. Para tanto foram utilizados 270 dentes bovinos no qual foram realizadas restaurações Classe II variando o aparelho e o tempo de fotoativação, aplicado no sistema adesivo ou resina composta. Após isto, as restaurações foram submetidas ao teste infiltração marginal. De acordo com os resultados obtidos (Análise de Variância (p=0,05) e teste de Tukey) e sob as condições experimentais deste estudo, pôde-se concluir que: 1) o aumento do tempo de fotoativação do sistema adesivo não mostrou melhores resultados no processo de infiltração marginal, independente da fonte luz utilizada; 2) o aumento do tempo de fotoativação da resina composta não mostrou melhores resultados no processo de infiltração marginal, independente da fonte luz utilizada; 3) a utilização de aparelhos fotopolimerizadores com maiores intensidades de luz não mostrou melhores resultados quando comparados ao de menor intensidade, quando utilizados paar fotoativação da resina composta; 4) houve aumento da infiltração marginal após os testes de ciclagem mecânica e térmica nos grupos LED 3a geração e halógena quando estes foram utilizados para fotoativação da resina composta. / Abstract: The maintenance of the bond integrity between tooth and resin systems is important for the clinical success of composite resin restorations. Thus, the aim of this "in vitro" study composed of two manuscripts, was to evaluate the microleakage of Class II dental restorations: 1) made with an adhesive system and a dental composite, varying light curing time and light curing modes of the adhesive system, submitted to the thermal and mechanical loading cycling; 2) made with an adhesive system and a dental composite, varying light curing time and light curing modes of the resin, submitted or not to the thermal and mechanical loading cycling. 270 bovine teeth were used for this study, and prepared Class II restorations varying the time and the light curing modes for the adhesive or composite resin. After that, the restorations were submitted to the microleakage test. Based on the results (Analysis of Variance (p=0,05) and Tukey test), within the experimental limits of this study, it can be concluded that: 1) the increase of the light curing time of an adhesive system did not show better results in the process of marginal microleakage, regardless the light curing modes used; 2) increasing the photoactivation time of the resin composite did not reduce the microleakage of the cervical interface of the restoration, regardless the light curing modes used; 3) use of light curing units with high irradiance did not show better results when compared with low irradiant energy, for the two first layers of resin composite; 4) the thermal and mechanical loading cycling increased the microleakage in groups LED 3a generation and Conventional (QTH) for the two first layers of resin composite. / Mestrado / Dentística / Mestre em Clínica Odontológica

Orientador: Rafael Leonardo Xediek Consani / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-09T18:24:15Z (GMT). No. of bitstreams: 1 Lira_AndreaFabianade_M.pdf: 707416 bytes, checksum: 69b11fb51b91c668991278766f976aa6 (MD5) Previous issue date: 2007 / Resumo: O propósito deste trabalho foi estudar o efeito de métodos de contensão da mufla metálica (grampo convencional e sistema RS de contensão) e do tempo pós-prensagem (imediato e 6 horas) nos níveis de adaptação da base de prótese total superior confeccionada com as resinas acrílicas ativadas termicamente Clássico (Clássico) e QC-20 (Dentsply). Foram confeccionados 80 conjuntos modelo de gesso-base de cera distribuídos aleatoriamente em 8 grupos (n=10), de acordo com os métodos de contensão de mufla metálica e do tempo pós-prensagem. As resinas acrílicas foram proporcionadas e manipuladas de acordo com as instruções dos fabricantes e prensadas na fase plástica, com carga inicial de 850 kgf e final de 1250 kgf em prensa hidráulica de bancada. As bases confeccionadas em resina Clássico foram polimerizadas em ciclo de água a 74?C por 9 horas e as bases de resina QC-20 em água em ebulição por 20 minutos. Depois de esfriadas até atingir a temperatura ambiente, as bases foram desincluídas, acabadas, fixadas nos respectivos modelos de gesso com adesivo à base de cianoacrilato e seccionadas em três secções, correspondentes à distal de caninos, mesial de primeiros molares e região palatina posterior. Em cada secção, o desajuste entre modelo de gesso e base de resina foi verificado nos pontos referenciais fundo de sulco vestibular direito e esquerdo, crista do rebordo alveolar direito e esquerdo e linha mediana palatina posterior, com microscópio comparador linear Olympus, com precisão de 0,0005 mm. Os resultados coletados foram submetidos à análise de variância e ao teste de Tukey (5%). O dispositivo RS produziu níveis médios de adaptação com diferença estatística significante quando comparado com o grampo convencional, independente dos demais fatores. O dispositivo RS produziu níveis médios de adaptação nos tempos imediato e 6 horas com diferença estatística significante quando comparado com o grampo convencional. A polimerização imediata produziu valores entre cortes sem diferença estatística significativa quando comparada com a polimerização após 6 horas. Quando os cortes foram analisados no fator prensagem, os melhores níveis de adaptação foram obtidos com o dispositivo RS, com diferença estatística significativa quando comparado com o grampo convencional. Os tratamentos RS e convencional apresentaram comportamento semelhante, independente da resina, mas foram diferentes no tempo pós-prensagem. A região posterior apresentou maiores valores de desadaptação em ambas as resinas, independente do tipo de contensão da mufla e do tempo pós-prensagem / Abstract: The purpose of this study was to verify the effect of flask closure method (conventional clamp and RS tension system) and post-pressing time (immediate and after 6 hours) on the maxillary denture base adaptation made with Classico and QC-20 heat?cured acrylic resins. Eighty maxillary stone cast/wax base sets were made and randomly assigned into 8 groups (n=10) according to the flask closure method and post- pressing time. The acrylic resins were proportioned and manipulated following the manufacturer?s instructions and flask pressed in the doughlike stage with an initial load of 850 kgf and final load of 1,250 kgf in hydraulic press. Classico acrylic resin was submitted to polymerization in water at 74°C during 9 hours in immediate or after 6 hour post-pressing times. QC-20 acrylic resin was submitted to polymerization in boiling water for 20 minutes. After bench cooling the resin bases were deflasked, finished, and fixed on the casts with instantaneous adhesive. The cast-resin base sets were laterally sectioned in the regions corresponding to the distal of canines (A), mesial of first molars (B), and posterior palatal zone (C). The gap between the stone cast and resin base was measured with an Olympus comparative microscope with accuracy of 0.0005mm at five referential points for each section. Data submitted to ANOVA and Tukey?s test (5%) showed that the RS system produced medium levels of adaptation with statistically significant difference when compared to the conventional clamp, independent of the other factors. RS system produced levels of adaptation in the immediate and 6 hours post-pressing times with statistical significant difference when compared to the conventional clamp. The immediate polymerization produced values among cuts without statistical difference when compared to the polymerization after 6 hours. When the cuts were analyzed in the factor flask pressure method, the best levels of adaptation were showed with the RS system, with statistical significant difference when compared to the conventional clamp. The RS system and conventional clamp treatments showed similar results independent of the resin factor; however they were different in the post-pressing time. The posterior region showed greater values of desadaptation in both resins, independent of the flask closure method and post-pressing time / Mestrado / Protese Dental / Mestre em Clínica Odontológica

Orientador: Mário Alexandre Coelho Sinhoreti / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-22T12:31:43Z (GMT). No. of bitstreams: 1 Grohmann_CaioViniciusSignorelli_M.pdf: 1289626 bytes, checksum: 3364946c62d131765f918bfae157fa67 (MD5) Previous issue date: 2013 / Resumo: O objetivo neste estudo foi determinar a influência da concentração e proporção de canforoquinona (CQ) e etil-dimetilaminobenzoato (amina terciária - DABE) em propriedades de compósitos microhíbridos experimentais. Foram testados o Grau de Conversão (GC), Amarelamento (AM), Módulo de Elasticidade (ME), Resistência à Flexão (RF), Sorção de Água (SO) e Solubilidade (SL). Para tanto, 10 compósitos experimentais com a mesma composição monomérica (Bis-GMA, UDMA, BisEMA e TEGDMA) foram manipulados, variando-se apenas as concentrações e proporções de CQ/DABE (% em peso): 0,4/0,4 (C1); 0,4/0,8 (C2); 0,6/0,6 (C3); 0,6/1,2 (C4); 0,8/0,8 (C5); 0,8/1,6 (C6); 1/1 (C7); 1/2 (C8); 1,5/1,5 (C9) e 1,5/3 (C10). Para o ensaio de GC, 8 espécimes de cada material foram confeccionados, a partir de uma matriz de silicone em forma de barra (comprimento = 7 mm; largura = 2mm e espessura = 1mm), os quais foram fotoativados com um aparelho LED (Radii Cal, SDI, 800 mW/cm2), durante 20 segundos. Após 24 horas, o GC foi analisado por Espectroscopia de Infravermelho Transformada de Fourier (FTIR). Posteriormente, as mesmas amostras foram submetidas ao ensaio de flexão de 3 pontos em máquina de ensaio universal (Instron), e a RF e ME calculados. Para os testes de AM, SO e SL, foi utilizada uma matriz de silicone cilíndrica (diâmetro = 6 mm e espessura = 0,5 mm), e confeccionadas 5 amostras de cada material para cada teste. Todas as amostras foram armazenadas em estufa a 37º C, até que fossem submetidas aos seus respectivos testes. O AM foi mensurado após 24 horas de armazenamento em água, utilizando o espectrofotômetro Chroma Meter CR-400 (Konica Minolta). A análise se baseou no eixo b* (+b = amarelo; -b = azul). Para os testes de SO e SL, as amostras foram dissecadas por 1 semana e pesadas diariamente até que a variação máxima de massa fosse de 0,0001 g de um dia para o outro, obtendo m1. Para obter m2, as amostras foram armazenadas em água por 1 semana e pesadas novamente, uma única vez. Por último, m3 foram obtidas do mesmo modo em que m1, após recondicionamento das amostras. Para o cálculo foram utilizadas as fórmulas: SO = (m2-m3) / V e SL = (m1-m3) / V. Após os testes, os dados foram submetidos ao ANOVA one-way e teste Tukey (5%). As diferentes concentrações e proporções de CQ e DABE não alteraram significativamente as propriedades de RF e SO. Por outro lado, o GC foi influenciado positivamente, seguindo a ordem crescente da concentração CQ/DABE (C1 a C10). A SL foi inversamente proporcional à concentração do sistema CQ/DABE. Já relacionado ao ME, observou-se valores diretamente proporcionais à porcentagem em volume de CQ/DABE. Os compósitos 9 e 10, com maiores concentrações de CQ, apresentaram maior AM, comparados aos demais. Pode-se concluir que as altas concentrações de CQ/DABE levaram às melhores propriedades, porém ao maior AM. O aumento na proporção do co-iniciador (DABE) não influenciou nas propriedades de todas as formulações experimentais / Abstract: The aim of this study was to determine the influence of the concentration and ratio of camphorquinone (CQ) and ethyl-dimethylaminobenzoic (tertiary amine - DABE) on properties of microhybrids experimental composites. It was tested Degree of Conversion (DC), Yellowing (YL), Elastic Modulus (EM), Flexural Strength (FS), Water Sorption (WSP) and Solubility (SL). For this, 10 experimental composites with the same monomer composition (Bis-GMA, UDMA, BisEMA and TEGDMA) were manipulated by varying the concentration and ratio of CQ / DABE (wt%): 0.4 / 0.4 (C1); 0.4 / 0.8 (C2); 0.6 / 0.6 (C3); 0.6 / 1.2 (C4); 0.8 / 0.8 (C5); 0. 8 / 1. 6 (C6); 1 / 1 (C7); 1 / 2 (C8); 1.5 / 1.5 (C9); 1.5 / 3 (C10). For DC testing, 8 specimens of each material were prepared from a matrix of silicone-shaped bar (length = 7 mm, width = 2 mm and thickness = 1mm), which were photoactivated with one LED unit (Radii Cal, SDI, 800 mW/cm²) for 20 seconds . After 24 hours, the DC was analyzed by Infrared Fourier Transformed (FTIR). Subsequently, the same samples were subjected to bending test of three points on a universal testing machine (Instron), and the FS and EM calculated. For testing of YL, WSP and SL was used an array of cylindrical silicon (diameter = 6 mm and thickness = 0.5 mm), and made 5 samples of each material for each test. All samples were stored at 37 º C until they were subjected to their respective tests. The YL was measured after 24 hours of storage in water using the spectrophotometer Chroma Meter CR-400 (Konica Minolta). The analysis was based on the axis b * (+ b = yellow,-b = blue). For testing WSP and SL, the samples were dissected for 1 week and weighed daily until the maximum variation in weight was 0.0001 g of an overnight, obtaining m1. For m2, the samples were stored in water for 1 week and weighed once again. Finally, m3 were obtained in the same manner in which m1, after reconditioning of samples. For the calculation, were used: WSP = (m2-m3) / V and SL = (m1-m3) / V. After the tests, the data were subjected to one-way ANOVA and Tukey test (5%). The different concentration and ratio of CQ and DABE not significantly altered the properties of FS and WSP. Moreover, the DC was influenced positively in the order of increasing concentration of CQ / DABE (C1 to C10). The SL was inversely proportional to the concentration of the system CQ / DABE. Related to EM, was observed values directly proportional to the percentage by volume of CQ / DABE. The composites 9 and 10, with higher concentration of CQ showed higher YL, compared to the others. It can be concluded that high concentrations of CQ / DABE took the best properties, but the larger YL. The increase in the proportion of co-initiator (DABE) did not affect the properties of all experimental formulations / Mestrado / Materiais Dentarios / Mestre em Materiais Dentários

The object of this research is to further investigate the possiblitiy of resolving racemic bases on an optically active cation exchange resin. Any success in this direction would help to explain the reason for Bunnett and Mark's failure, since the general assumption that selective adsorption of one enantimorph of a racemic compound on an active exchanger should occur has been verified by Grubhofer and Schleith. The work can be conveniently divided into two sections. a) The preparation of optically active cation exchange resins and, b) the use of these as resolving agents. P. 8

[No abstract submitted] / Science, Faculty of / Chemistry, Department of / Graduate

A dark red resin was isolated from the reaction mixture obtained by treatment of quinoline hydrochloride with zinc dust. Indications, from chromatographic studies of the resin, that it contained a number of different components led to extensive investigations of methods of separation. Satisfactory separation of the resin into pure components was finally achieved by a scheme which essentially involved fractional extraction and fractional adsorption-desorption. Three pure components were isolated, and characterized by chemical and physical analyses. Two of the components were suggested as heterocyclic compounds of quinoline probably of polymeric nature. The third component appeared to be an aniline type compound resulting from reductive cleavage of quinoline. Ultra-violet spectra of the isolated pure components supported the deductions made from chemical and other physical evidence. / Science, Faculty of / Chemistry, Department of / Graduate

Two samples of gum supposedly obtained from Sapotaceae achras and named "sapote gum" were studied using the methods of partition chromatography. The two samples were proven to be entirely different in composition and to constitute in fact two separate and distinct gums. The previously unreported gum was characterized and shown to contain D-xylose, L-arabinose, D-galactose, and one or more glucuronic acids, including some methoxy-glucuronic acid. A new spray reagent was developed for paper chromatography of the sugars, and a novel technique used for making permanent photographic prints of the papergrams. Crystalline sugars were obtained from hydrolysates in pure form by separation on partition columns of powdered cellulose. / Science, Faculty of / Chemistry, Department of / Graduate

Comparative studies were carried out on the curing kinetics, physical and mechanical properties of conventionally and microwave cured epoxy resins. Epoxy resins Araldite LY 5052 and DLS 772 were used for this study. 4 4' Diaminodiphenyl sulfone was used as a hardener in the preparation of both systems. Nuclear magnetic resonance and gel permeation chromatography were used to identify the chemical structure of the resins. Differential scanning calorimetry was used to monitor the curing kinetics of conventionally cured epoxy samples while a microwave heating calorimeter was used to monitor the curing kinetics of microwave cured epoxy samples 'in situ'. These studies were carried out under non-isothermal and isothermal conditions. For both conditions, there was a significant increase in the fractional conversion of the microwave cured samples compared to the conventionally cured samples. The curing reactions for samples cured using microwave heating took place over a smaller temperature range. Higher reaction rates were observed in the samples cured using microwave heating.There were some differences in the kinetic parameters of the non-isothermal curing reactions of samples cured using microwave and conventional heating. For the Araldite LY 5052 / 4 4' DDS epoxy system, the microwave cured samples had higher activation energy than conventionally cured samples, while for the Araldite DLS 772 / 4 4' DDS epoxy system, the microwave cured samples had lower activation energy. The activation energies of the microwave isothermal curing of both Araldite LY 5052 / 4 4' DDS and Araldite DLS 772 / 4 4'DDS epoxy systems were lower than the activation energies of the conventionally cured samples.Infrared spectroscopy showed that the curing reaction followed the same path during conventional and microwave heating. It also revealed that the reaction rate of the microwave cured samples was higher than the conventionally cured samples.For both epoxy systems, the microwave cured samples had a higher glass transition temperature (Tg) , higher cross-link density (v) and lower molecular weight between cross-links. These showed that the microwave cured samples had a more compact network structure than the conventionally cured samples, which is an indication of better mechanical properties.A microwave reaction system was used to successfully dissolve conventional and microwave cured samples of Araldite DLS 772 / 4 4' DDS epoxy system. The chemical structure of the decomposed product was determined.

Orientador: Luis Roberto Marcondes Martins / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-26T11:37:31Z (GMT). No. of bitstreams: 1 Bertaglia_PriscilaCamondy_D.pdf: 1620456 bytes, checksum: 044aa4cbf344b86191934f41f4525929 (MD5) Previous issue date: 2015 / Resumo: O objetivo deste estudo in vivo foi avaliar clinicamente através do critério USPHS e a sensibilidade pós-operatória de restaurações Classe I de compósito nanoparticulado, associado a sistemas de união do tipo condicionamento total e autocondicionante. Trinta e duas restaurações de amálgama Classe I foram substituídas por restaurações adesivas. Após a confecção do preparo cavitário, as restaurações foram confeccionadas aleatoriamente, sob isolamento absoluto, utilizando os seguintes grupos (n=8): G1 - Adper Single Bond 2 + Filtek Supreme XT (XT); G2 - Adper Easy One Bond + XT; G3 - Adper Scotchbond + XT; G4 - Clearfil SE Bond + Filtek XT. A sensibilidade pós-operatória foi analisada através de escores antes da substituição (T1) (baseline), após 15 dias (T2), 12 meses (T3) e 24 meses (T4), utilizando-se estímulo frio e escala analógica de dor. A avaliação clínica das restaurações foram realizadas através de exame clínico direto em campo limpo e seco, utilizando o critério USPHS. O preenchimento da ficha de avaliação clínica (estabilidade de cor, integridade marginal, alteração de cor marginal, forma anatômica e cárie secundária) foram realizados nos tempos T2, T3 e T4, por um único avaliador. Ao final das avaliações, os dados foram agrupados e analisados estatisticamente. Ao compararmos a sensibilidade pós-operatória entre os grupos, não houve diferença estatística durante os tempos analisados e todos os grupos se comportaram de maneira semelhante quando avaliamos um único grupo durante os tempos analisamos, obtendo diferença estatística somente no T2, com relação aos demais. Com relação a avaliação clínica através do critério USPHS modificado, podemos observar que o grupo 2 apresentou a pior performance clínica com quantidades expressivas de restaurações com alteração de integridade marginal e de cor marginal, sendo 37,5% que necessitaram troca da restauração (escores Charlie). Os demais grupos se comportaram de maneira semelhante, mantendo-se em nível aceitável após 24 meses. Após a análise dos resultados, podemos concluir que o sistema adesivo autocondicionante de passo único apresentou menor longevidade das restaurações confeccionadas, se comparado aos demais sistemas utilizados, devendo ser utilizado com critério / Abstract: The aim of this in vivo study was to evaluate clinically through the USPHS criteria and postoperative sensitivity in Class I restorations restored with etch-and-rinse and self-etch adhesive system. Thirty-two Class I amalgam restorations are replaced with adhesive restorations. After the cavity preparation, the restorations were made randomly, under rubber dam, using the following groups (n = 8): G1 - 2 Single Bond + Filtek Supreme XT (XT); G2 - Adper Easy Bond + XT; G3 - Adper Scotchbond + XT; G4 - Clearfil SE Bond + XT. Postoperative sensitivity was analyzed using scores before (T1) (baseline), after 15 days (T2), 12 months (T3) and 24 months (T4), using cold stimulus and analog pain scale. The clinical evaluation of restorations were performed by USPHS criteria. The clinical evaluation (color stability, marginal integrity, marginal change color, anatomic form and secondary caries) were performed at the times T2 and T4, by a single evaluator. At the end of the assessment, data were grouped and analyzed statistically. No statistically significant difference when we compared the postoperative sensitivity between groups during the analyzed times and all groups behaved similarly when we evaluated a single group during the time, presenting statistical difference in T2 if we compared to others . The USPHS modified criteria indicated that G2 (EB+XT) had a worse clinical performance with significant amounts of exchanged restorations (37.5% requiring replacement - Charlie scores) with modification of marginal adaptation and marginal staining, . The other groups behaved similarly. The restorations were considered acceptable after 24 months. It is concluded that the one-step self-etching adhesive system showed a lower restoration longevity if compared to other systems used. The 2-step self-etch, 2-step and 3-step etch-and-rinse adhesive systems showed similar clinical results / Doutorado / Dentística / Doutora em Clínica Odontológica