Orientador: Angela Cristina Cilense Zuanon / Resumo: O cimento de ionômero de vidro (CIV) apresenta características favoráveis como ação antimicrobiana e capacidade de remineralização. A fim de potencializar essas propriedades, sua associação com outros materiais como as nanopartículas (NP) e os vidros bioativos (VB) é estudada e muita atenção deve ser voltada às possíveis alterações que podem ocorrer em suas propriedades físicas, mecânicas e químicas. O objetivo deste estudo foi avaliar propriedades físicas e mecânicas do CIV associado a NP de hidroxiapatita (HPa) a 5% e ao VB 45S5 a 10%, antes e após teste de escovação, em diferentes tempos de armazenamento. Foram avaliadas rugosidade superficial com auxílio de rugosímetro, dureza Vickers por meio de microdurômetro, e variação de massa do material medida por pesagens em balança analítica, além da análise qualitativa de sua superfície, por meio de perfilômetro, nos tempos de 1, 7, 15, 30 e 60 dias, antes e após o teste de escovação. Os dados obtidos foram analisados estatisticamente quanto à normalidade e a homogeneidade. A distribuição foi não normal e os testes não-paramétricos de Wilcoxon, e de Kruskal Wallis seguido pelo de Dunn foram realizados, todos com um nível de significância de 5%. Pode-se observar maiores valores para a perda de massa no primeiro dia de experimento para todos os grupos. A rugosidade superficial foi menor nos grupos Controle e NP aos 30 dias de experimento após o ensaio de escovação. A análise qualitativa por meio do perfil dos materiais confirma a ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The glass ionomer cement (GIC) has favorable characteristics such as antimicrobial action and remineralization capacity. In order to potentiate these properties, its association with other materials such as nanoparticles (NP) and bioactive glasses (BAG) is studied, and a great deal of attention must be given to the possible changes that may occur in the physical, mechanical and chemical properties. The objective of this study was to evaluate the physical and mechanical properties of GIC associated with 5% of hydroxyapatite NP (NPHPa) and of 10% BAG 45S5 before and after brushing test at different storage times. The surface roughness was evaluated using a rugosimeter, Vickers hardness by microdurometer, and mass variation of the material measured by analytical weighing, as well as the qualitative analysis of its surface by means of a profilometer at the times of 1, 7, 15, 30 and 60 days, before and after the brushing test. The data obtained were statistically analyzed for normality and homogeneity. The distribution was non-normal and the non-parametric Wilcoxon and Kruskal Wallis followed by Dunn's tests were performed, all with a significance level of 5%. It is possible to observe higher values for the loss of mass in the first day of experiment for all the groups. The surface roughness was lower in the control and NP groups at 30 days of experiment after the brushing test. The qualitative analysis through the profile of the materials confirms these findings. Larger values fo... (Complete abstract click electronic access below) / Mestre

Hexaferrites have a broad scope for application based on their physical properties. To study the influence of replacing cerium and gadolinium ions in hexaferrites, it is very important to understand their structural, electrical, and magnetic properties of hexaferrites. In this regard, the W-type strontium hexaferrite doped with Ce3 + and Gd3+ ions was prepared using a proteic sol-gel process under a pressure of 3000 psi and sintered at 1200º C for 2 h at a heating rate of 1 and 2º C/min. A pure W-type strontium hexaferrite was identified using X-ray diffraction (XRD); the XRD patterns exhibited increasing lattice parameters and unit cell volume as a function of doping. Scanning electron microscopy analysis indicated growth on plates with hexagonal divisions. The inserted Gd3+ and Ce3+ ions caused imbalance in the lattice. Therefore, some of the Fe3+ ions present in the octahedral site were converted to Fe2+ ions. Thus, the Curie temperature was reduced to 474º C, increasing the coercivity and reducing the superexchange interactions between Fe-O. The high saturation magnetization and low coercivity in the samples indicate that the hexaferrites are potential candidates for applications involving microwave absorption. In addition, impedance spectroscopy measurements indicated the presence of a replacement threshold with rare earth ions, which results in an increased resistivity; this is predominantly mediated by oxygen vacancies in the Ce3+-doped hexaferrite. / As hexaferritas apresentam um vasto campo de aplicações a depender de suas propriedades físicas. Estudar a influência da substituição dos íons de cério e gadolínio é de suma importância para entender como funciona o mecanismo de obtenção das propriedades estruturais, elétricas e magnéticas nas hexaferritas. Dessa forma, a hexaferrita de estrôncio tipo W foi dopada com íons de Ce3+ e Gd3+ foi obtida via processo sol-gel proteico à 3000 psi e sinterizada a 1200º C/2h com taxa de aquecimento de 1 e 2 /C/min. A fase pura da hexaferrita de estrôncio tipo W foi identificada por difração de raios X com aumento dos parâmetros de rede e volume da cela unitária em função da dopagem. As análises de microscopia eletrônica de varredura indicam o crescimento em placas com clivagens hexagonais. . Os íons de Gd3+ e Ce3+ quando inseridos provocou um desbalanceamento de cargas, levando a transformação de certa quantidade de íons Fe3+, presente no sítio octaédrico, para Fe2+. Tal fato leva a redução da temperatura de Curie para 474º C, aumento da coercividade e redução das interações de super troca entre Fe-O. A alta magnetização de saturação e baixa coercividade apresentadas pelas amostras, indicam que as hexaferritas são considerados candidatos em potencial para fins de absorção de micro-ondas. Além disso, as medidas de espectroscopia de impedância indicam que existe um limiar de substituição com os íons terra rara para que haja aumento da resistividade e a condução ocorra predominantemente mediada por vacâncias de oxigênio na hexaferrita dopada com íon de Ce3+. Palavras

Orientadores: Antonio Jose de Almeida Meirelles, Fabio Rodolfo Miguel Batista / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-27T18:12:26Z (GMT). No. of bitstreams: 1 Lucchesi_KarolynneWeber_M.pdf: 2545312 bytes, checksum: 924445a68faa88732383166e326ff7eb (MD5) Previous issue date: 2015 / Resumo: A biomassa de microalgas vem despertando grande interesse científico como matéria prima para produção de biodiesel, devido ao elevado teor de óleo de algumas espécies, além de ser uma importante fonte para a produção de diversos biocompostos. Seu cultivo não compete com a produção de alimentos e ainda auxilia na captura de CO2, tendo um impacto benéfico para o meio ambiente. Diante desta promissora potencialidade, este trabalho objetiva investigar a produção de ésteres etílicos a partir de óleo de microalgas, avaliando as propriedades físicas destes ésteres e do óleo, além de estudar o equilíbrio líquido-líquido de algumas misturas de interesse. Óleo comercial de microalga da espécie Chlorella protothecoides, obtido junto à empresa Solebyo, foi utilizado como matéria prima para a produção do biodiesel (etanol como álcool reagente), obtendo-se um biocombustível totalmente renovável. O óleo foi caracterizado em termos dos seus ácidos graxos, estimando-se sua composição em triacilgliceróis (TAG). A dependência da viscosidade e densidade com relação à temperatura, índice de acidez e teor de umidade, foram determinados para o óleo e seu respectivo biodiesel. Uma análise adicional de ponto de fulgor foi realizada exclusivamente para o biodiesel. Por fim, o estudo do equilíbrio líquido - líquido das misturas biodiesel de microalgas + glicerol + etanol e óleo de microalgas + biodiesel de microalga + etanol, foi realizado a 25, 40 e 55 °C. Estes sistemas têm importância nas diversas etapas da reação de transesterificação e nas etapas de purificação do biodiesel. A técnica de HPSEC foi utilizada para quantificar os componentes nas fases e a modelagem do equilíbrio foi realizada utilizando os modelos NRTL e UNIQUAC. Todos os sistemas apresentaram desvios de balanço menores que 0,5%, indicando uma boa qualidade dos dados experimentais e da técnica utilizada. A grande semelhança entre as propriedades do óleo e do biodiesel de microalgas com relação a óleos e biodieseis convencionais indica uma grande potencialidade desta matéria prima para a produção de biodiesel / Abstract: The biomass of microalgae has been attracting great scientific interest as raw material for biodiesel (fatty acid esters), due to the high oil content of some species, and its importance for biocompounds production. Its great advantage with respect to traditional raw materials (oil) is centered on the fact that the microalgae cultivation does not compete with the food production, especially regarding the production of biofuels, and aids in the capture of CO2, having a beneficial impact to the environment. Given this promising potential, this work aims to investigate the production of ethyl esters from microalgae oil, evaluating the physical properties of these esters and oil, as well as studying liquid-liquid equilibrium of mixtures of interest.For this purpose, commercial microalgae oil of the species Chlorella protothecoides, obtained from Soleybio company, was used as raw material for biodiesel production and ethanol as reagent alcohol, giving to this biofuel a completely renewable character. The oil was characterized in terms of their fatty acids and its composition in triglycerides (TAG) was estimated. The viscosity and density temperature dependence, acidity number and moisture content were determined for oil and its respective biodiesel. Analysis of flash point has been made exclusively for biodiesel. Finally, the study of the liquid - liquid equilibrium of mixtures biodiesel + glycerol + ethanol and microalgae biodiesel + ethanol + oil was performed at 25, 40 and 55 °C. These systems are important in various stages of transesterification reaction and in the steps of biodiesel purification. The HPSEC technique was used to quantify the components at equilibrium phases and the equilibrium modeling was performed using the NRTL and UNIQUAC models. All the systems studied in this work presented balance deviations lower than 0.5%, indicating a good quality of the experimental data and the technique used. The great similarity between the properties of microalgae oil and biodiesel with respect to conventional oils and biodiesels indicate a high potential of microalgae as alternative raw material for the production of biofuels / Mestrado / Engenharia de Alimentos / Mestra em Engenharia de Alimentos

Orientador: Gladis Camarini / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-27T20:22:32Z (GMT). No. of bitstreams: 1 Pinto_MariaClaraCavalini_M.pdf: 8053440 bytes, checksum: bbe81de24c0023c7d27c30c6e2aeb3c0 (MD5) Previous issue date: 2014 / Resumo: As novas leis ambientais vem forçando a sociedade e empresas a mudar suas atitudes com relação à geração e destino dos resíduos. A produção indiscriminada desses rejeitos e a deposição incorreta do material vem causando impactos ambientais, apresentando-se como um grave problema de gestão pública, pois precisam ser descartados em aterros especiais. Um número limitado desses aterros especiais foram construídos para receber os resíduos de gesso, o que pode motivar a destinação dos resíduos de gesso para centrais de reciclagem. O gesso reciclado é obtido por meio de um simples processo de moagem e calcinação em temperaturas relativamente baixas. Comprovou-se, em trabalhos anteriores, que o gesso reciclado endurece rapidamente, reduzindo seu tempo de aplicação. Aditivos retardadores de pega do gesso têm sido estudados, contudo os testes são baseados em gesso comercial. A escolha de um aditivo adequado, bem como de sua dosagem, pode melhorar o tempo de pega do gesso reciclado, de modo a permitir a reaplicação do produto em obras e na produção de componentes. O objetivo deste trabalho foi estudar as propriedades do gesso reciclado, tanto no estado fresco como no endurecido, com o uso de aditivos retardadores: ácido cítrico, tânico, tartárico e citrato de sódio. Foram avaliadas a consistência, tempo de pega, cinética da temperatura, resistência à compressão, dureza e microestrutura. Os resultados mostraram que alguns aditivos foram capazes de alterar as propriedades do gesso reciclado. No estado fresco, o gesso reciclado teve seu tempo de pega aumentado por influência do ácido cítrico e do citrato de sódio. No estado endurecido, o ácido cítrico e o citrato de sódio reduziram a resistência à compressão e a dureza do gesso reciclado. O ácido tânico e o ácido tartárico, por outro lado, não alteraram significativamente o comportamento do gesso reciclado / Abstract: The new environmental laws are forcing the society and the enterprises to change their attitudes regarding the generation and the destination of wastes. The indiscriminate production of these wastes is causing environmental impacts, presenting itself as a serious problem of public management because it must be discharged in special landfills. A limited number of cells have been built for receiving sulfate waste, which may encourage this waste transfer to special recycling stations. The recycled gypsum plaster is obtained by a simple process of crushing and heating at relatively low temperatures. Previous works on gypsum recycling show that recycled gypsum plaster has fast setting and lack of workability. Gypsum retarders have been studied intensively, but the emphasis was always laid on commercial gypsum. The selection of suitable retarders and dosage can adjust the setting times of recycled gypsum plaster to a desired level to use this material again in construction works or to make components. The present study investigated the properties of recycled gypsum plaster with added citric, tannic, tartaric acid and sodium citrate to improve the performance in fresh and hardened states. The consistency, the setting times and kinetics of temperature, compressive strength, hardness and microstructure were evaluated. The results show that some admixtures can modify the recycled plaster properties. Setting times of the recycled plaster increased by influence of the citric acid and sodium citrate. Compressive strength and hardness were reduced by using citric acid and sodium citrate. On the other hand, tannic and tartaric acid did not change significantly the recycled plaster behavior / Mestrado / Arquitetura e Construção / Mestra em Engenharia Civil

Realizou-se, no contexto deste trabalho, o estudo de espécies tropicais de madeira e a qualificação destas a partir de suas características físicas, de resistência e rigidez. Os ensaios para a determinação das propriedades foram realizados no Laboratório de Madeiras e de Estruturas de Madeira, do Departamento de Engenharia de Estruturas, Escola de Engenharia de São Carlos, seguindo as recomendações do anexo B da NBR 7190/1997 - Projeto de Estruturas de Madeira. O objetivo fundamental é gerar informações que possam fornecer suporte para um direcionamento e perspectiva de novas possibilidades de aplicação na construção civil: construção de estruturas para diferentes finalidades (coberturas, pontes, cimbramentos); industriais para componentes de edificações (pisos, caixilhos); armazenamento; obras portuárias; entre outras. / It was realized, in the context of this work, a study about tropical wood species and their qualification, based on the physical and mechanical properties. The tests to the determination of such properties were realized in Wood and Timber Structures Laboratory, Structural Engineering Departament, São Carlos Engineering School, according to the recommendations of the Annex B, NBR 7190/1997 - Timber Structures Design. The mean subject is to generate information to permit new application in civil construction: structures for different purposes (roofs, bridges, formwork); industrial to building components; storage; among others.

Thesis (MSc. (Soil Science)) -- University of Limpopo, 2015 / There exists a considerable level of spatial variability in soil physical and chemical properties within the research block; and the soils are generally shallow. Of all the measured parameters, electrical conductivity, Bray-1 P, exchangeable potassium, calcium and sodium as well as extractable iron and zinc showed a huge percent of variation across the field. Soil variability maps indicated the degree of variability within the research block. The spatial variability of the characterized parameters was significant across the research block. A correlation study was conducted to investigate the relationship between the measured soil physical and chemical properties. Regular soil analyses should be conducted to avoid failure/delay of experiments. It is recommended that inputs such as irrigation and fertilizer application must be varied based on varying soil conditions across the research block. / VLIR project 6 leaders

In donor-acceptor systems, ultrafast interfacial charge transfer (CT), charge separation (CS) and charge recombination (CR), are among the key factors in determining the overall efficiency of the optoelectronic devices. In this regime, precise knowledge of the mechanisms of these processes on the femtosecond scale is urgently required. In this dissertation, using femtosecond transient absorption and mid-Infrared spectroscopies along with steady-state absorption and emission measurements, we are not only able to address the fundamental understanding of these ultrafast dynamical processes, but also control them at various inter- and intramolecular electron donor-electron acceptor systems. In the photoinduced intermolecular charge transfer systems, where donor and acceptor are separated from each other, three systems have been investigated; cationic poly[(9,9-di(3,3′-N,N′-trimethylammonium) propyl fluorenyl-2,7-diyl)-alt-co-(9,9-dioctyl-fluorenyl-2,7-diyl)] diiodide salt (PFN) conjugated polymer donor with 1,4-dicyanobenzene (DCB) acceptor, negatively charged porphyrin (POS) donor with positively charged (PFN) acceptor, and finally, positively charged (PFN) donor with negatively charged graphene carboxylate (GC) acceptor. Based on studying these three systems, we were able to explore some important factors and deriving forces including chemical structure, electrostatic interactions, energy band alignment, hydrogen bonding and solvents with different polarities and capabilities for hydrogen bonding that influence the rate and efficiency of the charge transfer at the interfaces of these donor-acceptor systems. For instance, unlike the conventional understanding of the key role of hydrogen bonding in promoting the charge-transfer process, our results reveal that the hydrogen-bonding increases the spacing between the donor and acceptor units which significantly hinders the charge-transfer process. On the other hand, in the photoinduced intramolecular charge transfer systems, where donor and acceptor are chemically attached to each other, we investigate the effects of conjugation length on photoinduced charge transfer in π-conjugated oligomers naphthalene diimide (NDI) end-capped oligo(phenylene ethynylene)s (PEn-NDI), and poly-(phenylene ethynylene) (PPE) donor backbone with (NDI) acceptor end-caps (PPE-NDI-n) systems. The results of femtosecond transient absorption and mid-IR spectroscopies show that the charge separation occurs on the 1-10 ps time scale with the rates decreasing as oligomer length increases in PEn-NDI system. In addition, in PPE-NDI-n system, the fluorescence quenching measurements indicate very efficient photoinduced electron transfer from the PPE backbone to the NDI end-groups, and the transfer efficiency increases with decreasing the number of units. Finally, the new physical insights reported in this thesis provide an understanding of several key variable components involved, thus paving the way toward the exploitation of efficient charge transfer at donor-acceptor interfaces, which is the key element and urgently required for optimal optoelectronic-device performance.

PhD (Food Science and Technology) / Department of Food Science and Technology / Finger millet (FM) (Eleusine coracana) grains are the staple food in Africa and India for communities with low socio-economic growth. The grains have high content of calcium, dietary fibre, carbohydrates that are rich in protein, fat, iron, phosphorus, vitamin and essential amino acids. Flours from milky cream (MC), brown and black varieties of FM were fortified with vitamin (vit) B₂ and zinc oxide (ZnO) in order to restore the nutrients that were lost during milling and sieving processes. The main aim of the study was to analyse the physical, nutritional composition and functional properties of flours from three (3) FM varieties fortified with vit B2 and ZnO. Pearl millet was used for comparison with the results obtained from this study. MC, brown and black varieties of FM flour treatments were arranged as a completely randomized design (CRD) in three (3) replicates. Physical properties: dimensional properties, colour attributes, kernel weight, bulk density (BD), true density, porosity, surface area, kernel volume, aspect ratio, sphericity and moisture content of the FM grains were analysed. Vitamins and minerals were also analysed. Functional properties: colour attributes, bulk density (BD), water absorption capacity (WAC), oil absorption capacity (OAC), swelling capacity (SC), swelling index (SI), foaming capacity (FC), foaming solubility (FS), dispersibility (Dis), viscosity (cool & hot paste), pasting properties, thermal properties and microscopic structure of FM flours were determined. Data generated were analysed using SPSS version 23.0. Moisture content of MC FM grain and flour was significantly higher (p < 0.05) than brown and black varieties but was within the specified range of <12%. This indicated the long storage shelf-life of the grains and flours. Length of brown FM grains was significantly higher (p < 0.05) when compared to MC and black varieties. MC variety was significantly higher than other varieties in width, kernel weight, bulk density, true density, aspect ratio and sphericity. The information obtained from this study will help in designing suitable equipment for planting, harvesting, storage, processing and packaging of grains. Pearl millet grain was significantly higher than FM flours in all physical properties. MC FM was significantly higher iii in L* (whiteness/ brightness), b* (yellowness/ blueness), C* (chroma), Hº (hue angle) and ZnO values compared to brown and black flours. MC raw fortified finger millet (RFFM) and instant fortified finger millet (IFFM) flours were significantly higher in vitamin B2. People prefer fortified MC flour because most of people living in South Africa use white maize as their staple food and it is similar to MC. Colour is the most important quality parameter in food processing industries and it is also attracts the consumer’s choice and preference. The vitamins and minerals that were lost during sieving, drying and milling were replaced by the two (2) fortificants added which may help to reduce the micronutrient deficiencies. Milky cream FM flours showed significantly high (p < 0.05) values in BD, WAC, OAC, SI, FC and dis. These are the fundamental physico-chemical properties that reflect the interaction between the composition and molecular structure. Length of brown FM grains was significantly higher (p < 0.05) when compared to MC and black variety. The MC variety was significantly higher than other varieties in width, kernel weight, bulk density, true density, aspect ratio and sphericity. Pearl millet was significantly higher than FM flours in all physical properties. MCFM variety was significantly higher in L* (whiteness/ brightness), b* (yellowness/ blueness), C* (chroma), and Hº (hue angle) values as compared to other FM varieties. Moisture content of MC flour was significantly higher as compared to brown and black FM flours. Pasting properties of MC raw finger millet (RFM) and RFFM flours showed significantly higher in peak viscosity (PV) (3518 cP), final viscosity (FV) (6554 cP), breakdown viscosity (BDV) (703 cP) and setback viscosity (SV) (3868 cP) as compared to other RFM and RFFM flours. Brown instant finger millet (IFM) and IFFM flours had significantly higher of PV (723 cP), trough viscosity (TV) (655 cP) and FV (983 cP). IFFM flours had significantly higher values of PV (712 cP), TV (614 cP) and FV (970 cP), respectively. The instant pearl millet (IPM) and instant fortified pearl millet (IFPM) showed significantly higher value in BDV (330 cP and 131 cP) and SV (362 cP and 346 cP), respectively. Thermal properties of black RFM was significantly higher in onset temperature (To) (74.31), peak temperature (TP) (81.94ºC) and conclusion temperature (Tc) (89.64) and RFFM starches were significantly high in To (81.80ºC), TP (84.22ºC) and TC (92.81ºC), respectively. Milky ivcream IFM starch showed significantly higher values in TO (84.57ºC), TP (87.27ºC), Tc (92.81ºC) and ΔH (7.63ºC) compared to other starches. Brown IFFM flour was significantly higher value in To (85.88ºC) and TP (87.14ºC). The starch of IFPM was significantly higher in enthalpy of gelatinisation (6.91ºC) and PHI (2.94ºC) as compared to other FM starches. Brown IFM flour showed significantly higher value in gelatinisation temperature range (13.50ºC). The microscopic structure revealed that RFM and RFFM flours had oval and smooth surfaces. RFM and RFFM flours showed positive effect after fortificants were added because the starch granules, protein bodies and protein matrix were visible and formed crystal. IFM and IFFM flours had some holes, dents and rough surfaces. Instant fortified flours showed negative effect after fortificants were added due to technological processes such as recooking and remilling of flours. Different variations observed on physical, nutritional and functional properties after adding the fortificants may affect the physical, chemical and organoleptic properties of food produced from fortified flour. There is need to fortify FM flours with ZnO which may help to replace the value lost during milling and sieving operations. It is possible that the availability of ZnO could reduce the incidence of some non-communicable diseases. / NRF

Summary: Diploma thesis covers characterization of molecular crystals by X-ray structural analysis. N-carbamimidazoylisonikotinamid and 1-phenylguanidin were chosen, because their potential use in second harmony generation. Their salts with inorganic acids were prepared and determined their structures. Phase transition of 4,6-diaminopyrimidinium nitrate was studied by x-ray diffraction and differential scanning calorimetry. This phase transition is accompanied by thermosalient effect, causing that the crystals jump. Keywords: thermosalient, jumping crystal, X-ray diffraction, non-linear optics, N-carbamimidazoylnikotinamid, 1-phenylguanidin, 4,6diaminopyrmidin.

Magister Theologiae - MTh / This study aimed to determine the association between dimensional change and surface roughness (Ra) of Vitremer, Activa and Cention N after immersing them into two different media: acidic and artificial saliva media for the period of a year. Measurements were made at 10 time intervals during the observation period.