Orientador: Maria Alvina Krähenbühl / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-25T22:39:27Z (GMT). No. of bitstreams: 1 Batista_MatheusMaciel_D.pdf: 6291864 bytes, checksum: b2aef4c09ed3d6ce4ce6e0de8c505d7d (MD5) Previous issue date: 2014 / Resumo: A busca por combustíveis alternativos vem ganhando destaque nas últimas décadas. A substituição de combustíveis fósseis tem sido impulsionada por fatores ambientais, econômicos e sociais, uma vez que toda a sociedade depende de seu uso. Neste contexto, uma alternativa que tem se destacado é o do biodiesel. O biodiesel representa uma alternativa renovável, biodegradável, não inflamável e de baixa toxicidade para o diesel. Os parâmetros de solubilidade tridimensional definidos por Hansen são baseados em forças de dispersão entre as unidades estruturais, interações entre os grupos polares e de ligação de hidrogênio. Estes parâmetros de solubilidade são propriedades importantes de várias substâncias e ferramentas muito úteis para a seleção de seus solventes ou a previsão de seu comportamento em diferentes aplicações. A sua concepção e avaliação baseia-se na regra básica de "similaridade" para solubilidade. Neste trabalho foram determinados os parâmetros de solubilidade de Hansen (?D, ?P e ?H) e raio da esfera de solubilidade do soluto (R0) para os óleos de soja, fritura, palma, coco e mamona; para os biodieseis provenientes desses óleos, diesel e blendas biodiesel-diesel (B10 e B20), usando 45 solventes e misturas de solventes. Os valores dos parâmetros de solubilidade obtidos para os óleos de soja e fritura foram idênticos e similares àqueles obtidos para os óleos de coco e palma. O óleo de mamona apresentou maiores valores ?P e ?H, devido à presença de uma hidroxila em sua estrutura carbônica. O mesmo comportamento foi observado para os biodieseis, ou seja, biodieseis de soja e fritura, com parâmetros de solubilidade idênticos, e similares aos biodieseis de palma e coco; o biodiesel de mamona exibindo valores de ?P e ?H mais elevados entre os biocombustíveis produzidos. Os parâmetros de solubilidade de Hansen de quatro biocombustíveis (soja, palma, coco e mamona) foram obtidos a partir dos valores da média dos parâmetros de solubilidade dos ésteres graxos metílicos, proveniente de cada óleo vegetal, utilizando os métodos de contribuição de grupos. Posteriormente, as solubilidades dos biocombustíveis foram preditas usando abordagens de van Krevelen, Greenhalgh e Bagley. O óleo diesel apresentou menores valores de ?D, ?P e ?H se comparado com os valores obtidos para os biodieseis. Os valores dos parâmetros de solubilidade do diesel, B10 e B20 foram semelhantes, aumentando os valores de acordo com a quantidade (em volume) de biodiesel adicionado ao combustível diesel / Abstract: The search for alternative fuels has been gaining attention in recent decades. The replacement of fossil fuels has been driven by environmental, economic and social factors, since the whole of society is dependent on their usage. In this context, one alternative that has been highlighted is that of biodiesel. Biodiesel represents a renewable, biodegradable, non-inflammable and low toxicity alternative to diesel. The three dimensional solubility parameters defined by Hansen are based on dispersion forces between structural units, interaction between polar groups and hydrogen bonding. These solubility parameters are important properties of the various substances and very useful tools in the selection of their solvents or the prediction of their behavior in different applications. Their design and evaluation are based on the basic rule of "similarity" for solubility. In this work the Hansen solubility parameters (?D, ?P and ?H) and the radii of the solubility spheres of the solutes (R0) were determined for soybean, frying, palm, coconut and castor oils, for the biodiesels obtained from these oils and diesel and the biodiesel-diesel blends (B10 and B20), using 45 solvents and solvent mixtures. The values obtained for the solubility parameters of the soybean and frying oils were identical and similar to those obtained for the coconut and palm oils. Castor oil showed higher ?P and ?H values due to the presence of a hydroxyl in its carbon structure. The same behavior was observed for the biodiesels, i.e. identical solubility parameters for the soybean and frying biodiesels which were similar to the palm and coconut biodiesels, the castor biodiesel showing the highest values for ?P and ?H of the biofuels produced. The Hansen solubility parameters for four biofuels (soybean, palm, coconut and castor) were obtained from the values of the average solubility parameter for the fatty acid methyl esters derived from any vegetable oil, using the group contribution methods. Subsequently, the values for the solubility of the biofuels were predicted using the van Krevelen, Greenhalgh, and Bagley approaches. Diesel presented lower values for ?D, ?P and ?H when compared to the values obtained for the biodiesels. The values of the solubility parameters of diesel, B10 and B20 were similar, the values increasing according to the amount (by volume) of biodiesel added to the diesel fuel / Doutorado / Desenvolvimento de Processos Químicos / Doutor em Engenharia Química

Orientador: Giselle Maria Marchi Baron / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-21T14:45:08Z (GMT). No. of bitstreams: 1 Andrade_KamilaMenezesGuedesde_M.pdf: 1062095 bytes, checksum: 01a4c768f4297c41306904dc584e5faa (MD5) Previous issue date: 2012 / Resumo: O objetivo deste estudo foi avaliar a influência da adição de diferentes concentrações do sal hexafluorofosfato de difeniliodônio (DFI) nas propriedades de cimentos resinosos experimentais fotopolimerizáveis contendo as diferentes aminas terciárias Dimetilaminoetil metacrilato (DMAEMA) e Dimetilaminoetl benzoato (EDAB) em diferentes concentrações. À composição base de monômeros Bis-GMA e TEGDMA (1:1 em peso) foi adicionado 1 mol% do fotoiniciador canforoquinona (CQ) e 0,1 mol% do inibidor Hidroxitolueno butilado (BHT). A adição dos co-iniciadores variou em 0, 0,5 e 1mol% de DFI; 1 e 2 mol% de DMAEMA; 1 e 2 mol% de EDAB. Cada concentração de amina foi combinada a cada concentração do sal, totalizando 12 grupos experimentais. Após a manipulação da matriz resinosa, 60% em peso de partículas inorgânicas silanizadas de vidro de bário-alumínio-silicato foram adicionadas. As propriedades analisadas foram sorção (SR) e solubilidade (SL) em água destilada (n=5); Resistência à flexão (RF) e módulo de elasticidade (E) (n=10) e Grau de conversão (GC) (n=5). A análise estatística foi realizada com significância de 5%, para cada teste separadamente. Os resultados mostraram que a adição de diferentes concentrações do DFI, DMAEMA e EDAB influenciaram todas as propriedades testadas. Formulações contendo DMAEMA 1 mol% foram mais sensíveis à adição de 0,5 mol% DFI, apresentando aumento do GC, RF, E e diminuição de SR. O acréscimo de 1 mol% DFI aumentou a SR, E e diminuiu a SL e o GC. Cimentos contendo 2 mol% DMAEMA apresentaram aumento no GC, RF e E com adição de 0,5 mol% DFI e menores valores de SL. A amina EDAB 1 mol% foi influenciada pelas duas concentrações de DFI com aumento gradativo da SR e aumento do GC. A concentração de 2 mol% EDAB foi pouco influenciada pela adição do sal. Pode-se concluir que a adição do DFI melhora os cimentos contendo DMAEMA de forma mais significativa que os cimentos contendo EDAB. Formulações com 2mol% das aminas são mais estáveis para a maioria dos testes realizados / Abstract: The goal of this study was to evaluate the influence of the addition of different concentrations of diphenyliodonium hexafluorophosphate (DPI) on the properties of photoactivaed experimental resin cements containing dimethylaminoethil methacrylate (DMAEMA) and dimethylaminoethil benzoate (EDAB) in different concentrations. To the Bis-GMA/TEGDMA comonomer blend (1:1 in weight) was added 1 mol% of the photoinitiator camphorquinone (CQ) and 0,1 mol% of the inhibitor hydroxyl butyl toluene (BHT). The addition of the co-initiators varied in 0, 0,5 and 1 mol% of DPI; 1 and 2 mol% of DMAEMA; 1 and 2 mol% of EDAB. Each amine concentration was combined to each salt concentration in 12 experimental groups. After the manipulation of the resin matrix, 60% in weight of inorganic sillanated particles of Ba-Al-Si glass were added. The analysed properties were sorption (SR) and solubility (SL) in distilled water (n=5); Flexural strength (FS) and elasticity modulus (E) (n=10) and degree of conversion (DC) (n=5). The statistical analysis was done with significance of 5% to each test separately. The results showed that the addition of different concentrations of DPI, DMAEMA and EDAB had an influence on all the tested properties. Formulations containing 1 mol% of DMAEMA were more sensitive to the addition of 0,5 mol% of DPI, presenting an increase on DC, RF, E and decrease on SR. The addition of 1 mol% of DPI increased the SR, the E and decreased the SL and the DC. Cements containing 2 mol% of DMAEMA presented increase on DC, FS and E with the addition of 0,5 mol% of DPI and minor values of SL. The amine EDAB 1 mol % was influenced by the two concentrations of DFI with gradual increase of the SR and increase of the DC. The concentration of 2 mol% of EDAB was little influenced by the addition of the salt. In conclusion, the addition of the DPI improves the cements containing DMAEMA in a more significant way than the cements containing EDAB. Formulations with 2 mol% of the amines are more stable to most of the realized tests / Mestrado / Dentística / Mestra em Clínica Odontológica

Orientador: Everson Alves Miranda / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-04T07:13:28Z (GMT). No. of bitstreams: 1 Barros_GeorgiadeOliveiraFigueiredo_M.pdf: 2282903 bytes, checksum: b104323f697a813ec6af57b15ba7b95b (MD5) Previous issue date: 2005 / Resumo: A separação de enantiômetros em altos níveis de pureza enantiomérica é atualmente um requerimento da industria farmacêutica. No entanto, altas purezas estão sendo alcançadas neste sistema com comprometimento da produtividade. O acoplamento do leito móvel simulado (LSM) a uma etapa de cristalização pode resultar num processo de maior produtividade global . A escolha do método de cristalização para a resolução de misturas racêmicas por cristalização é dependente do tipo de cristal (conglomerado ou composto racêmico) e da localização do ponto eutético no diagrama de solubilidade. O ponto eutético difine a mínima puraza enantiomérica que deve ser fornecida pelo LMS para assegurar que a cristalização irá produzir somente um dos enantiômeros puros. A cetamina é um anstésico que possui um isômero R com indesejáveis efeitos colaterais. O objetivo deste trabalho é trabalho é o desenvolvimento de conhecimento básico (identificação do tipo de racemato e seu ponto eutético no diagrama de solubilidade) para o acolplamento do LMS a uma etapa de cristalização a fim de produzir o isômero S da cetamina em pureza enantiomérica e produtividade alta. Para caracterizar a natureza cristalina da cetamina, diração de raios-X e espectroscopia de infravermelho da mistura racêmica e dos enantilômero puros foram realizados e as curvas de solubilidade em função da temperatura foram determinadas...Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital / Abstract: The resolution of enantiomers to high levels of enantiomeric purity is presntly a requeriment in the pharmaceutical industry. However, high, purities are reached with this system at the expenses of productivity. Coupling of simulated moving bed (SMB) to a crystallization step can result in a process whith a overall higher productivity. The choise ofcristallization method for the resolution of racemic mixtures is dependent on the eutetic point on the solubility diagram. Eutetic point is the minimum enantiomeric purity that has to be delivered by the SMB to assure that crystallization will produce just one pure isomer. Ketamine is a anesthetic that has a R-isomer with undesirable side-effect. The objective of this work was development of basic knowlwdge for a process (identification of the type of racemate and its eutetic point in the solubility diagram) coupling the SMB to a crystallization step in order to produce the S-isomer of ketamine at high enantiomeric purity and productivity. To characterize the crystalline nature of ketamine, X-ray diffraction and infrared spectroscopy of the racemic mixture and pure enantiomers were performed between powder x-ray pattems, infrared spectra, and solubility curve slopes of the pure enantiomers and racemic mixture indicated racemic compound formation...Note: The complete abstract is available with the full electronic digital thesis or dissertations / Mestrado / Desenvolvimento de Processos Biotecnologicos / Mestre em Engenharia Química

L'objectif de cette thèse est l'obtention de nouvelles données expérimentales en milieu acide borique dans le cadre du développement de modèles décrivant le comportement des produits de corrosion dans le circuit primaire, et notamment sur le relâchement du nickel par des phénomènes de dissolution/précipitation. Le travail présenté dans ce mémoire s'est focalisé sur une des phases solides du nickel, l'oxyde de nickel (NiO), ainsi que sur le comportement en solution de sa forme ionique, Ni2+. La solubilité de l'oxyde de nickel a été mesurée à haute température à l'aide d'un réacteur à circulation ouverte spécialement conçu pour fonctionner à haute température et haute pression. Compte tenu des concentrations très faibles en Ni dans les conditions de nos essais (300°C, pH>7, matrice bore-lithium), une méthode d'analyse du nickel dissous à l'échelle de l'ultra-trace (ng.kg-1) en milieu bore-lithium a été développée par ICP-MS et a été validée statistiquement par la méthode du profil d'exactitude. La complexation du nickel par les (poly)borates a ensuite été étudiée. Une expérience a été conduite où les ions nickel sont progressivement formés par oxydation d'une électrode de nickel métallique dans une solution d'acide borique. Basé sur les résultats expérimentaux et sur la modélisation de la spéciation aqueuse du bore, l'évolution du pH a montré l'existence significative d'un complexe nickel-bore. Le complexe neutre NiB3O4(OH)3 a été mis en évidence pour de fortes concentrations en acide borique, lorsque les polyborates sont présents. Les constantes d'équilibres ont été calculées à 25, 50 et 70°C, ainsi que les données thermodynamiques associées. Enfin, les cinétiques de dissolution de l'oxyde de nickel ont été mesurées en milieu acide chlorhydrique et en milieu acide borique de 25 à 100°C et un pH de 6. Les résultats ont mis en évidence un effet inhibiteur de l'acide borique sur les vitesses de dissolution de NiO dont le phénomène est exacerbé par l'augmentation de la température et de la concentration en bore. La formation d'un complexe surfacique a été mise en avant pour expliquer cet effet. / This work focuses on the nickel oxide phase (NiO) and the behavior in solution of its ionic form Ni2+. The solubility of nickel oxide has been determined at high temperature and pressure by the use of a flow through cell reactor specially designed to perform measurements in the conditions of the primary circuit. Because the solubility of nickel is very low at 300°C and pH>7, a new method for the determination of ultra-traces nickel concentrations in lithium/boron medium by ICP-MS coupled with a desolvator system nebulizer has been developed and validated by the statistical approach of accuracy profiles. The complexation of nickel by the (poly)borates has been also studied. Based on the experimental results and aqueous speciation modeling, the evolution of pH showed the existence of significant nickel-boron complexation. A neutral complex NiB3O4(OH)3 was postulated at high boric acid concentrations when polyborates are present, and the equilibrium constants were determined at 25, 50 and 70°C. The associated thermodynamics data have also been determined. Dissolution rates of nickel oxide have been measured in hydrochloric acid and in boric acid media up to 100°C and pH 6. Results showed that boric acid inhibits the dissolution rates of NiO and this phenomenon is enhanced by the temperature and the concentration of boron. The formation of a surface complex was postulated to explain this effect.

No description available.

Les matériaux basés sur le système Fe-Ni-Cr utilisés à haute température doivent présenter une bonne résistance à l'oxydation, généralement obtenu par la croissance lente d’une couche d’oxyde de chrome à la surface de ces alliages. Pour prédire la formation d'une couche d’oxyde protectrice la perméabilité de l'oxygène dans l’alliage doit être connue, la perméabilité étant définie comme le produit de la solubilité et du coefficient de diffusion de l’oxygène. L'objectif de nos travaux est de mesurer la perméabilité, la solubilité et la diffusivité de l'oxygène dans des alliages Fe-Ni pour des températures supérieures à 1000°C. Afin d'obtenir les meilleurs résultats,la formation d'une couche externe d'oxyde pendant les expériences doit être évitée. Pour cela, la pression partielle d'oxygène a été fixée à la pression d'équilibre Fe/FeO dans toutes les expériences. En outre, afin d'étudier l'effet de la vapeur d'eau sur la perméabilité, la solubilité et la diffusivité de l’oxygène, deux atmosphères ont été utilisées: l’une considérée comme sèche et l’autre comme humide. L'atmosphère sèche a été obtenue en utilisant la technique du « pack de Rhines »: les échantillons sont oxydés dans des capsules en quartz sous vide qui contiennent un mélange de poudre de fer et de wüstite. L'atmosphère humide a quant à elle été obtenue en utilisant des mélanges gazeux H2/H2O avec un ratio approprié de vapeur d'eau et d’hydrogène afin de fixer la pression partielle d’oxygène à la pression d’équilibre Fe/FeO. Les mesures de solubilité réalisées dans ce travail ont montré que celle-ci atteint son maximum dans le fer pur et diminue avec l’ajout de nickel. Cependant, la dépendance de la solubilité avec la composition de l’alliage Fe-Ni n'est pas idéale et ne peut être prédite à partir de modèles simples. De plus, les résultats obtenus sous atmosphère humide suggèrent que la présence de vapeur d'eau dans l'atmosphère augmente la solubilité de l'oxygène d’un facteur 2 dans les alliages avec une concentration en nickel inférieure ou égale à 60 at.% pour des températures proches de 1000°C,tandis qu'à 1150°C, la solubilité de l'oxygène est indépendante de l'environnement. La perméabilité de l'oxygène a été déterminée en mesurant la cinétique d'oxydation interne d'alliages Fe-Ni-Cr. Les résultats ont montré que la perméabilité de l'oxygène présente les mêmes variations avec la composition de l’alliage que la solubilité de l'oxygène, indépendamment de l'atmosphère.De plus, aucun effet significatif de la vapeur d'eau sur les valeurs de perméabilité de l'oxygène n'a été observé. Le coefficient de diffusion de l'oxygène a également été déterminé en utilisant les résultats précédents, c’est à dire la perméabilité et la solubilité de l’oxygène mesurées dans notre étude. Pour une température supérieure à 1000°C, la variation du coefficient de diffusion de l'oxygène avec la composition de l'alliage est similaire dans tous les environnements testés et un maximum est observé pour les alliages avec une teneur en nickel de 40 at.%. Cependant, la présence de vapeur d'eau dans l'atmosphère diminue les valeurs du coefficient de diffusion de l'oxygène, par un facteur 2-3 à 1000°C, pour les alliages avec une concentration en nickel inférieure ou égal à 60 at.%. De plus, il a été trouvé que la différence entre les coefficients de diffusion mesurés dans l’atmosphère sèche et humide augmente à mesure que la température diminue. En conclusion, il a été constaté que la vapeur d'eau n'a aucun effet sur la manière dont la perméabilité, la solubilité et la diffusivité de l'oxygène varient avec la composition des alliages Fe-Ni. Cependant, la présence de vapeur d'eau dans l'environnement semble augmenter la solubilité de l'oxygène et diminuer sa diffusivité dans les alliages riches en fer. De plus, l’effet de la vapeur d’eau apparaît plus important aux plus basses températures étudiées. / It is a worldwide priority to reduce emissions of greenhouse gases such as CO2. One solution for reducing these emissions is to improve the efficiency of energy production units by increasing their operating temperature. However, in order to increase operating temperature, new austenitic materials based on the Fe-Ni-Cr system have to be designed. In addition, these materials need to exhibit good protection against high temperature oxidation, which is achieved by the formation of a slow growing chromium oxide or alumina scale on the metal. However, to predict the formation of a protective scale, knowledge of the oxygen permeability, the product of oxygen solubility and diffusivity, in the base alloy is required. The objective of this study is to measure the permeability, solubility and diffusivity of oxygen in Fe- Ni alloys at temperatures above 1,000°C. In order to obtain the best results, the formation of an external oxide layer during the experiment has to be avoided. To achieve this, the oxygen partial pressure was fixed at the Fe/FeO equilibrium pressure in all experiments. In addition, two types of atmospheres were used: one dry and one wet, in order to investigate the effect of water vapour on oxygen permeability, solubility and diffusivity. The dry atmosphere was achieved using the Rhines Pack technique. The samples were oxidised in vacuum-sealed quartz capsules, which contained a mixture of powdered iron and wüstite. The humid atmosphere was obtained by using H2/H2O gas mixtures with the appropriate water vapour to hydrogen ratio to fix oxygen partial pressure at the Fe/FeO equilibrium. The maximum oxygen solubility was found in pure iron, and decreased continuously with nickel additions to the alloy. The dependence of solubility on alloy composition is non-ideal, and cannot be predicted from simple models. Moreover, the presence of water vapour in the atmosphere seems to increase the solubility by a factor of 2 in alloys with nickel content lower than 80 at.% at temperatures near 1,000°C. However, at 1,150°C the solubility of the oxygen is independent of the environment. The oxygen permeability was determined by measuring the internal oxidation kinetics of Fe-Ni-Cr alloy. These kinetics were evaluated by measuring the internal oxidation zone depth by optical microscopy, or by continuous and discontinuous thermogravimetry. Results showed that the oxygen permeability exhibits the same variation with alloy composition as the oxygen solubility, independent of the atmosphere. In particular, no significant effect of water vapour on oxygen permeability values was observed. In the present study, the oxygen diffusion coefficient was also determined using permeability, in addition to the independent measurement of the oxygen solubility carried out in the present study. For temperature above 1,000°C, the variation of oxygen diffusion coefficient with the alloy composition is similar in all environments tested, and a maximum is observed for alloys with a nickel content of 40 at.%. However, for a given nickel content up to 60 at.%, the presence of water vapour in the atmosphere decreases the value of the oxygen diffusion coefficient by a factor of 2-3 at 1,000°C. In addition, this difference between diffusion coefficients measured in a dry and wet atmosphere increases as the temperature decreases. Overall, it was found that the water vapour has no effect on the way in which oxygen permeability, solubility and diffusivity vary with the alloy composition. However, the presence of water vapour in the environment appears to increase the oxygen solubility and decrease the oxygen diffusivity in iron-rich alloys, the effect being more significant at low temperatures. These results suggest further research into interactions between O, H and metal vacancies, particularly for temperature around 1,000°C and below, as the latter defect is thought to change the diffusion and solubility properties of interstitial species.

Master of Science / Food Science Institute / Jayendra K. Amamcharla / Milk protein concentrate (MPC) powders are high-protein dairy ingredients obtained from membrane filtration processes and subsequent spray drying. MPC powders have extensive applications due to their nutritional, functional, and sensory properties. However, their flow properties, rehydration behavior, and morphological characteristics are affected by various factors such as processing, storage, particle size, and composition of the powder. Literature has shown that knowledge about the powder flowability characteristics is critical in their handling, processing, and subsequent storage. For this study, FT4 powder rheometer (FT4, Freeman Technologies, UK) was used to characterize the flowability of MPC powders during storage. This study investigated the flowability and morphological characteristics of commercial MPC powders with three different protein contents (70, 80, and 90%, w/w) after storage at 25ºC and 40ºC for 12 weeks. Powder flow properties (basic flowability energy (BFE), flow rate index (FRI), permeability, etc.) and shear properties (cohesion, flow function, etc.) were evaluated. After 12 weeks of storage at 40ºC, the BFE and FRI values significantly increased (P < 0.05) as the protein content increased from 70 to 90% (w/w). Dynamic flow tests indicated that MPC powders with high protein contents displayed higher permeability. Shear tests confirmed that samples stored at 40ºC were relatively less flowable than samples stored at 25ºC. Also, the lower protein content samples showed better shear flow behavior. The results indicated that MPC powders stored at 40ºC had more cohesiveness and poor flow characteristics than MPC powders stored at 25ºC. The circle equivalent diameter, circularity, and elongation of MPC powders increased as protein content and storage temperature increased, while the convexity decreased as protein content and storage temperature increased. Overall, the MPC powders evidently showed different flow properties and morphological characteristics due to their difference in composition and storage temperature. Literature has shown various methods for determining the solubility of dairy powders, but it requires expensive instruments and skilled technicians. The front-face fluorescence spectroscopy (FFFS) coupled with chemometrics could be used as an efficient alternative, which is commonly used as fingerprints of the various food products. To evaluate FFFS as a useful tool for the non-destructive measurement of solubility in the MPC powders, commercially procured MPC powders were stored at two temperatures (25 and 40ºC) for 1, 2, 4, 8, and 12 weeks to produce powders with different rehydration properties, which subsequently influenced their fluorescence spectra. The spectra of tryptophan and Maillard products were recorded and analyzed with principal components analysis. The solubility index and the relative dissolution index (RDI) obtained from focused beam reflectance measurement was used to predict solubility and dissolution changes using fluorescence spectra of tryptophan and Maillard products. The solubility index and RDI showed that the MPC powders had decreased solubility as the storage time and temperature increased. The results suggest that FFFS has the potential to provide rapid, nondestructive, and accurate measurements of rehydration behavior in MPC powders. Overall, the results indicated that solubility and dissolution behavior of MPC powders were related to protein content and storage conditions that could be measured using FFFS.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The knowledge of previous conceptions of students is an important tool in the teaching-learning process, since it can significantly help the planning of educational activities. Solubility is a fundamental concept in Chemistry present in a wide range of everyday situations; however, it is little explored regarding previous conceptions. In this context, this study aimed to investigate the previous conceptions of high school students on solubility, to evaluate if Biology and Chemistry teachers develop experimental and interdisciplinary activities on the theme and to elaborate a booklet with experiments on solubility. The study was performed in public schools of Santa Maria-RS and Rosário do Sul-RS and involved 314 students and 30 teachers of Biology and Chemistry. In order to investigate the previous conceptions of students, we used a semi-structured questionnaire for data collection consisting of questions concerning the concept of solubility, the importance of this concept in everyday life and the existence of correlation of this content with the content studied in Biology. With regard to Biology and Chemistry teachers, we used a closed questionnaire with issues related to the workload of teachers, the realization of practical classes and the interdisciplinary approach of the solubility content. In general, we verified that students have knowledge about solubility, but little is based on scientific knowledge. Students also reported the importance of this knowledge mainly regarding the food. The results obtained also showed that most of the teachers do not work the theme solubility in an interdisciplinary way or perform experimental activities related to it. Therefore, we can conclude that some teachers still have a fragmented and compartmentalized teaching, where the student is a mere receiver of knowledge. After the analysis of the data obtained, a booklet will be prepared with experiments on solubility, which will be distributed to teachers participating the research in order to help them carry out these experiments and develop new experimental activities in the classroom. / O conhecimento das concepções prévias dos estudantes constitui uma ferramenta de grande importância no processo de ensino-aprendizagem, uma vez que estas podem auxiliar de forma significativa no planejamento de atividades pedagógicas. Um conceito fundamental em Química e pouco explorado nas investigações sobre concepções prévias é o conceito de solubilidade, o qual está presente em uma vasta gama de situações do cotidiano. Neste contexto, o presente estudo teve como objetivos: investigar as concepções prévias de estudantes do Ensino Médio sobre solubilidade; averiguar se os professores de Biologia e Química desenvolvem atividades experimentais e interdisciplinares sobre o tema; e elaborar uma apostila com experimentos sobre solubilidade. O estudo foi realizado em Escolas Públicas de Santa Maria-RS e Rosário do Sul-RS e envolveu 314 estudantes e 30 professores de Biologia e Química. A fim de investigar as concepções dos estudantes, foi utilizado para coleta de dados um questionário semi-estruturado composto por questões referentes ao conceito de solubilidade, a aplicabilidade deste conceito no dia a dia e a existência de correlação deste conteúdo com os trabalhados em Biologia. Com relação aos professores de Biologia e Química, foi utilizado um questionário fechado composto por questões referentes à carga horária dos professores, a realização de aulas práticas e a abordagem interdisciplinar do conteúdo solubilidade. De forma geral, verificou-se com este estudo, que os estudantes possuem conhecimentos sobre o tema solubilidade, porém pouco ancorados em conhecimentos científicos e que também relacionam a importância deste conhecimento principalmente com a Alimentação. Os resultados obtidos, também mostram que a maioria dos professores não trabalha o tema Solubilidade de forma interdisciplinar e nem realiza atividades experimentais sobre conteúdos relacionados. Pode-se concluir que alguns professores ainda mantêm um Ensino fragmentado e compartimentalizado, onde o estudante é um mero receptor de conhecimentos. Após a análise dos dados obtidos, será elaborada uma apostila com experimentos sobre solubilidade, a qual será distribuída aos professores participantes da pesquisa. Pretende-se auxiliá-los na execução destes experimentos e no desenvolvimento de novas atividades experimentais em sala de aula.

The Swedish government has decided that waste containing more than 0.1% mercury is to be placed in a permanent repository in the bedrock1,10. To minimize the risk of spreading mercury, elemental mercury must first be converted into a practically insoluble compound. In a PhD investigation of stabilization attempts at SAKAB AB in Kumla favorable conditions for conversion of mercury to cinnabar (the sparingly soluble sulphide form of mercury and the naturally occurring mineral) was found. In a long-term study of diffusion of mercury it was found that water solubility of mercury varied much, from 0.05 to 5 μmolL-1. To be able to study the water solubility of mercury as detailed as possible a speciation method was developed and verified. This investigation includes how different parameters, like matrix properties and Hg0/solution ratios effects the solubility of mercury and how the different species are distributed in the water phase. The total solubility of mercury is very dependent of both the matrix properties and the Hg0/solution ratio. Aqueous elemental mercury (Hg0 aq) is not as matrix dependent as the oxidized species. However, trends show that a higher Hg0/solution ratio contributes to a higher solubility of Hg0 aq. Factors like time, pH, ionic strength and degree of stirring, greatly effects the total solubility of mercury. The concentration of the oxidized mercury species generated from elemental mercury increases over time and is very dependent on the properties of the matrix. After 18 hours the solubility of Hg0 aq ranges from 0.2 to 0.7 μmolL-1, depending on Hg0/solution ratio. The solubility for the oxidized species has a much larger variation, ranging from 0.1 to 28.6 μmolL-1. Among other things, because the composition and redox potential of the matrix plays an important role in what mercuric complexes can be expected to form, and contribute to the solubility. / Det har beslutats av regeringen att senast år 2010 skall kvicksilverhaltigt avfall med en kvicksilverhalt på mer än 0.1% slutförvaras i en stabiliserad from djupt ner i berggrunden. I en doktorsavhandling som genomförts på SAKAB AB i Kumla har det konstaterats att det är möjligt att överföra elementärt kvicksilver till cinnober, den stabila sulfidformen av kvicksilver som för övrigt är ett naturligt förekommande mineral. Experiment som pågått under lång tid för att studera det elementära kvicksilvrets diffusion under olika omständigheter har också utförts. De uppmätta halterna i vattenfasen har varierat mycket, från 0.05 till 5 μmolL-1. Det är vad som ligger till grund för det här arbetet. För att kvicksilvers löslighet skall kunna studeras fullt ut har en specierings metod vidareutvecklats och verifierats att den fungerar. Studien innefattar hur lösligheten av kvicksilver påverkas av olika parametrar, som till exempel; matriser med olika egenskaper och olika kvicksilver/vatten kvoter, samt hur fördelningen mellan oxiderade species och det elementära kvicksilvret är i vattenfasen (Hg0 aq). Den totala lösligheten av kvicksilver beror dels av matrisens egenskaper och mängden kvicksilver i förhållande till mängden vätska. Lösligheten av Hg0 aq är inte lika beroende av matrisen som de oxiderade species. Däremot finns trender som visar att högre Hg0/lösning kvot bidrar till en aningen högre löslighet av Hg0 aq. Tid, konduktivitet, pH och omrörning spelar stor roll för vilken totalhalt och hur stor andel oxiderade species man får i vattenfasen. Lösligheten av Hg0 aq, efter 18 timmar, varierar mellan 0.2 till 0.7 μmolL-1, beroende på Hg0/lösning kvoten. Efter 18 timmar är lösligheten för de oxiderade species mycket mer varierande, från 0.1 till 28.6 μmolL-1. Detta beror bland annat på att matrisens sammansättning och redoxpotential spelar en viktig roll för vilka komplex som kan bildas med kvicksilverjonerna och på så sätt bidra till en ökad löslighet.

The importance of renewable energy sources is becoming clearer and clearer as unsustainable energy sources are running out and global warming is getting worse. Energy derived from sunlight is already commonly used, but more energy can be produced from sunlight when solar cells become cheaper. Organic solar cells use organic compounds as semiconductors which can be prepared from solutions, resulting in lower production costs. However, these semiconductors;Poly(3-hexylthiophene) and [6,6]-Phenyl-C61-butric acid methyl ester, are commonly dissolved inhalogenated and aromatic solvents. These solvents have toxic properties, which is why alternative solvents should be identified. Potential solvents were predicted by using the Hansen solubilityparameters and thin films were prepared by spin-coating the solutions. The thin films were evaluated with absorption spectroscopy, the fluorescence spectroscopy and atomic force microscopy. Since the alternative solvents had lower solubilites than the commonly used solvents, i.e., chlorobenzene, ortho-dichlorobenzene and chloroform, the absorption of the films with new solvents were lower as well. Using tetrahydrofuran resulted in the highest absorption of the used solvents, while xylene hada better film morphology. Increasing the absorption was attempted by spin-coating multiple thin films on top each other or by using a lower rotational speed. Spin-coating multiple films had nouniform effect on the absorption, while lowering the rotational speed increased the absorption, but not enough to equal the original absorption. Contrasting the results of the absorption spectra, the morphology improved when multiple layers were used while the film with the lower rotational speed’s morphology got worse. In conclusion, tetrahydrofuran and xylene are the best alternative solvents and using multiple layers as well as decreasing the rotational speed show improvements oneither the morphology or the absorption.