The effect of preharvest foliar applications of ethephon and postharvest curing on baked sweet potatoes (Ipomoea batata) were analyzed. Ethylene had negative effects on appearance of baked roots while curing increased the total phenolics in sweet potatoes. Panelists preferred the non-ethylene treated and green or cured over ethylene treated sweet potatoes with respect to texture, color and flavor. No differences in chemical or color properties were found between treatments. The effect of curing time (0, 7, 14 days) on baked sweet potatoes was studied. Curing caused more browning on flesh of sweet potatoes. Moreover, panelists preferred the texture of the green over the cured roots but did not find any differences in flavor sensory quality. The effect of hot water treatment on sprouting and spoilage of cured sweet potatoes was investigated. The most effective treatment was at 53-56 °C for less than 10 min, resulting in less than 60% (control=80%).

This research addresses the novel application of design of experiment, artificial neural net-works and logistic regression to study the effect of demographic characteristics on the risk of acquiring HIV infection among the antenatal clinic attendees in South Africa. The annual antenatal HIV survey is the only major national indicator for HIV prevalence in South Africa. This is a vital technique to understand the changes in the HIV epidemic over time. The annual antenatal clinic data contains the following demographic characteristics for each pregnant woman; age (herein called mother's age), partner's age (herein father's age), population group (race), level of education, gravidity (number of pregnancies), parity (number of children born), HIV and syphilis status. This project applied a screening design of experiment technique to rank the effects of individual demographic characteristics on the risk of acquiring an HIV infection. There are a various screening design techniques such as fractional or full factorial and Plackett-Burman designs. In this work, a two-level fractional factorial design was selected for the purposes of screening. In addition to screening designs, this project employed response surface methodologies (RSM) to estimate interaction and quadratic effects of demographic characteristics using a central composite face-centered and a Box-Behnken design. Furthermore, this research presents the novel application of multi-layer perceptron’s (MLP) neural networks to model the demographic characteristics of antenatal clinic attendees. A review report was produced to study the application of neural networks to modelling HIV/AIDS around the world. The latter report is important to enhance our understanding of the extent to which neural networks have been applied to study the HIV/AIDS pandemic. Finally, a binary logistic regression technique was employed to benchmark the results obtained by the design of experiments and neural networks methodologies. The two-level fractional factorial design demonstrated that HIV prevalence was highly sensitive to changes in the mother's age (15-55 years) and level of her education (Grades 0-13). The central composite face centered and Box-Behnken designs employed to study the individual and interaction effects of demographic characteristics on the spread of HIV in South Africa, demonstrated that HIV status of an antenatal clinic attendee was highly sensitive to changes in pregnant mother's age and her educational level. In addition, the interaction of the mother's age with other demographic characteristics was also found to be an important determinant of the risk of acquiring an HIV infection. Furthermore, the central composite face centered and Box-Behnken designs illustrated that, individual-ally the pregnant mother's parity and her partner's age had no marked effect on her HIV status. However, the pregnant woman’s parity and her male partner’s age did show marked effects on her HIV status in “two way interactions with other demographic characteristics”. The multilayer perceptron (MLP) sensitivity test also showed that the age of the pregnant woman had the greatest effect on the risk of acquiring an HIV infection, while her gravidity and syphilis status had the lowest effects. The outcome of the MLP modelling produced the same results obtained by the screening and response surface methodologies. The binary logistic regression technique was compared with a Box-Behnken design to further elucidate the differential effects of demographic characteristics on the risk of acquiring HIV amongst pregnant women. The two methodologies indicated that the age of the pregnant woman and her level of education had the most profound effects on her risk of acquiring an HIV infection. To facilitate the comparison of the performance of the classifiers used in this study, a receiver operating characteristics (ROC) curve was applied. Theoretically, an ROC analysis provides tools to select optimal models and to discard suboptimal ones independent from the cost context or the classification distribution. SAS Enterprise MinerTM was employed to develop the required receiver-of-characteristics (ROC) curves. To validate the results obtained by the above classification methodologies, a credit scoring add-on in SAS Enterprise MinerTM was used to build binary target scorecards comprised of HIV positive and negative datasets for probability determination. The process involved grouping variables using weights-of-evidence (WOE), prior to performing a logistic regression to produce predicted probabilities. The process of creating bins for the scorecard enables the study of the inherent relationship between demographic characteristics and an in-dividual’s HIV status. This technique increases the understanding of the risk ranking ability of the scorecard method, while offering an added advantage of being predictive.

This research addresses the novel application of design of experiment, artificial neural net-works and logistic regression to study the effect of demographic characteristics on the risk of acquiring HIV infection among the antenatal clinic attendees in South Africa. The annual antenatal HIV survey is the only major national indicator for HIV prevalence in South Africa. This is a vital technique to understand the changes in the HIV epidemic over time. The annual antenatal clinic data contains the following demographic characteristics for each pregnant woman; age (herein called mother's age), partner's age (herein father's age), population group (race), level of education, gravidity (number of pregnancies), parity (number of children born), HIV and syphilis status. This project applied a screening design of experiment technique to rank the effects of individual demographic characteristics on the risk of acquiring an HIV infection. There are a various screening design techniques such as fractional or full factorial and Plackett-Burman designs. In this work, a two-level fractional factorial design was selected for the purposes of screening. In addition to screening designs, this project employed response surface methodologies (RSM) to estimate interaction and quadratic effects of demographic characteristics using a central composite face-centered and a Box-Behnken design. Furthermore, this research presents the novel application of multi-layer perceptron’s (MLP) neural networks to model the demographic characteristics of antenatal clinic attendees. A review report was produced to study the application of neural networks to modelling HIV/AIDS around the world. The latter report is important to enhance our understanding of the extent to which neural networks have been applied to study the HIV/AIDS pandemic. Finally, a binary logistic regression technique was employed to benchmark the results obtained by the design of experiments and neural networks methodologies. The two-level fractional factorial design demonstrated that HIV prevalence was highly sensitive to changes in the mother's age (15-55 years) and level of her education (Grades 0-13). The central composite face centered and Box-Behnken designs employed to study the individual and interaction effects of demographic characteristics on the spread of HIV in South Africa, demonstrated that HIV status of an antenatal clinic attendee was highly sensitive to changes in pregnant mother's age and her educational level. In addition, the interaction of the mother's age with other demographic characteristics was also found to be an important determinant of the risk of acquiring an HIV infection. Furthermore, the central composite face centered and Box-Behnken designs illustrated that, individual-ally the pregnant mother's parity and her partner's age had no marked effect on her HIV status. However, the pregnant woman’s parity and her male partner’s age did show marked effects on her HIV status in “two way interactions with other demographic characteristics”. The multilayer perceptron (MLP) sensitivity test also showed that the age of the pregnant woman had the greatest effect on the risk of acquiring an HIV infection, while her gravidity and syphilis status had the lowest effects. The outcome of the MLP modelling produced the same results obtained by the screening and response surface methodologies. The binary logistic regression technique was compared with a Box-Behnken design to further elucidate the differential effects of demographic characteristics on the risk of acquiring HIV amongst pregnant women. The two methodologies indicated that the age of the pregnant woman and her level of education had the most profound effects on her risk of acquiring an HIV infection. To facilitate the comparison of the performance of the classifiers used in this study, a receiver operating characteristics (ROC) curve was applied. Theoretically, an ROC analysis provides tools to select optimal models and to discard suboptimal ones independent from the cost context or the classification distribution. SAS Enterprise MinerTM was employed to develop the required receiver-of-characteristics (ROC) curves. To validate the results obtained by the above classification methodologies, a credit scoring add-on in SAS Enterprise MinerTM was used to build binary target scorecards comprised of HIV positive and negative datasets for probability determination. The process involved grouping variables using weights-of-evidence (WOE), prior to performing a logistic regression to produce predicted probabilities. The process of creating bins for the scorecard enables the study of the inherent relationship between demographic characteristics and an in-dividual’s HIV status. This technique increases the understanding of the risk ranking ability of the scorecard method, while offering an added advantage of being predictive.

>Magister Scientiae - MSc / Liposomes as a drug carrier in the pharmaceutical industry has gained currency since its discovery in 1965 by Bangham A. D. Liposomes have been shown to improve bioavailability as they can be delivered to target sites and possess sustained release properties which could be used to mitigate certain weaknesses associated with current diclofenac sodium eye drops. Diclofenac sodium (DNa) eye drop is a sterile Nonsteroidal Anti-inflammatory Drug (NSAID) with diclofenac sodium as its active ingredient. It is indicated for the lessening of ocular pain, prevention of miosis in eye operations, easing of postoperative inflammation and cystoids macular edema. The residence time of eye drops after application has been found to be 1-2 minutes as a result of continuous production of tears diluting the active ingredient, draining the eye drops into the nasolacrimal path, and eliminating it during blinking. As a result of the active ingredient not residing at the target site for the required duration, more frequent administration and medication is required and the risk of non-compliance is increased. Given the aforementioned potential of liposomes to redress the above weaknesses of current eye drops (dosage form) available for diclofenac sodium ophthalmic application, this study sought to encapsulate diclofenac sodium into liposomes for ophthalmic application. The main components of liposomes (cholesterol and phosphotidylcholine) and incubation time were set as the independent variables while percentage encapsulation, polydispersity index (PDI) and drug release profile constituted the dependent variable. Using analysis of variance (ANOVA) and t-test statistics, the interaction between the independent variables and their effect on the dependent variables were tested.

O presente trabalho estuda a degradação fotocatalítica da nicotina em solução aquosa, um alcaloide altamente tóxico que tem sido detectado em efluentes, águas subterrâneas e água mineral. Os experimentos foram realizados em um reator batelada sob irradiação ultravioleta, tendo sido avaliadas três principais variáveis: concentração inicial do contaminante, concentração de catalisador e pH inicial da solução. Foram realizados dois planejamentos de experimentos para os catalisadores comerciais ZnO e TiO2, com o objetivo de encontrar a melhor condição para promover a degradação da nicotina em água. Outros catalisadores, preparados a partir de resíduos industriais e laboratoriais, foram testados nas condições otimizadas. O método analítico empregado para quantificar a nicotina nas amostras foi a cromatografia líquida de alta eficiência, o que permitiu registrar a formação de intermediários e subprodutos de reação. Os resultados experimentais demostraram que a degradação da nicotina por fotocatálise heterogênea é um processo bastante eficiente. Em ambos os planejamentos, o pH foi a variável que exerceu o maior efeito sobre a degradação, sendo este fortemente positivo. Já a concentração inicial de nicotina exerceu efeito negativo sobre a resposta e a concentração de catalisador em suspensão exibiu um ponto ótimo, que correspondeu a 0,91 g.L-1 para o ZnO, e 1,20 g.L-1 para o TiO2. Ensaios foram realizados nas condições otimizadas encontradas, onde cerca de 98% da molécula foi degradada utilizando ZnO em suspensão e 88% empregando TiO2, em uma hora de reação. A degradação fotocatalítica da nicotina demonstrou seguir uma cinética de pseudoprimeira ordem dentro do tempo de reação de 60 minutos, para os dois catalisadores comerciais. Entre os catalisadores não convencionais que foram testados, aquele que demonstrou o maior percentual de degradação foi obtido a partir de resíduo de uma indústria petroquímica, cerca de 43%. / The present work studies the photocatalytic degradation of nicotine in aqueous solution. This alkaloid is highly toxic and it has been detected in wastewater, groundwater and mineral water. The experiments were performed in a batch reactor under ultraviolet radiation. Three main variables of process were evaluated: initial concentration of pollutant, catalyst concentration and initial pH of the solution. Two experimental designs were performed for commercial catalysts ZnO and TiO2. The purpose was to find the best condition to promote the nicotine degradation in water. Other catalysts prepared from industrial and laboratory waste were tested under the optimized conditions. Analytical method used to quantify nicotine and its degradation products in all samples was high performance liquid chromatography. Experimental results showed that nicotine degradation by heterogeneous photocatalysis is a very efficient process. In both designs, initial pH was the most significant variable which has a strong positive effect. Initial nicotine concentration showed a negative effect, and catalyst concentration exhibited an optimal value for both commercial catalysts: 0,91 g.L-1 using ZnO, and 1,20 g.L-1 with TiO2. At the best conditions, about 98% of the molecule was degraded using ZnO and 88% with TiO2. Photocatalytic nicotine degradation followed a pseudo first order kinetic until 60 minutes of reaction for both commercial catalysts. Among the non-conventional catalysts tested, the one prepared from a petrochemical industry residue exhibited the highest photocatalytic degradation, about 43%.

Self compacting concrete (SCC) is first developed in Japan in the late 1980s in order to overcome the consolidation problems associated with the presence of congested reinforcement. It is also termed as a high performance concrete, as it can flow under its own weight and completely fill the formworks. As the fresh properties of SCC are quite important, mix design of a SCC is performed by considering various workability related fresh properties. Therefore, a well designed SCC should satisfy all requirements of a hardened concrete, besides its superior workability properties. The aim of this research is to assess the effects of some basic ingredients of SCC on the fresh properties of SCC. This will be performed by applying design of experiment techniques and obtaining significant statistical models, which will give valuable information about the effects of the model parameters on the rheology and fresh state characteristics of SCC. In this research program, four different variables / use of fly ash replacement, use of high range water reducing admixture (HRWRA), use of viscosity modifying admixtures (VMA) and water-cementitious material ratio, are considered as the variables of the experimental design. Central Composite Design (CCD), a design of experiment technique, is employed throughout the experimental program and a total of 21 mixtures of concrete are cast. Slump flow, V-funnel, L-box, sieve segregation, initial and final setting time tests are performed, furthermore / to investigate the effects of these variables to the rheology of SCC, relative plastic viscosity and relative yield stress, which are the parameters of Bingham Model are measured with the help of a concrete rheometer. As a result of the experimental program, the fresh state properties of SCC are expressed by mathematical equations. Those equations are then used in order to explain the effects of fly ash replacement, HRWRA and VMA concentration, and the w/cm ratio on the fresh state properties of SCC. According to the derived models, it is stated that the water-cementitious material ratio of the concrete mixture is the most effective parameter on the flowability and passing ability of SCC beside the other parameters utilized in this research as its coefficient was the highest in the related models.

O presente trabalho estuda a degradação fotocatalítica da nicotina em solução aquosa, um alcaloide altamente tóxico que tem sido detectado em efluentes, águas subterrâneas e água mineral. Os experimentos foram realizados em um reator batelada sob irradiação ultravioleta, tendo sido avaliadas três principais variáveis: concentração inicial do contaminante, concentração de catalisador e pH inicial da solução. Foram realizados dois planejamentos de experimentos para os catalisadores comerciais ZnO e TiO2, com o objetivo de encontrar a melhor condição para promover a degradação da nicotina em água. Outros catalisadores, preparados a partir de resíduos industriais e laboratoriais, foram testados nas condições otimizadas. O método analítico empregado para quantificar a nicotina nas amostras foi a cromatografia líquida de alta eficiência, o que permitiu registrar a formação de intermediários e subprodutos de reação. Os resultados experimentais demostraram que a degradação da nicotina por fotocatálise heterogênea é um processo bastante eficiente. Em ambos os planejamentos, o pH foi a variável que exerceu o maior efeito sobre a degradação, sendo este fortemente positivo. Já a concentração inicial de nicotina exerceu efeito negativo sobre a resposta e a concentração de catalisador em suspensão exibiu um ponto ótimo, que correspondeu a 0,91 g.L-1 para o ZnO, e 1,20 g.L-1 para o TiO2. Ensaios foram realizados nas condições otimizadas encontradas, onde cerca de 98% da molécula foi degradada utilizando ZnO em suspensão e 88% empregando TiO2, em uma hora de reação. A degradação fotocatalítica da nicotina demonstrou seguir uma cinética de pseudoprimeira ordem dentro do tempo de reação de 60 minutos, para os dois catalisadores comerciais. Entre os catalisadores não convencionais que foram testados, aquele que demonstrou o maior percentual de degradação foi obtido a partir de resíduo de uma indústria petroquímica, cerca de 43%. / The present work studies the photocatalytic degradation of nicotine in aqueous solution. This alkaloid is highly toxic and it has been detected in wastewater, groundwater and mineral water. The experiments were performed in a batch reactor under ultraviolet radiation. Three main variables of process were evaluated: initial concentration of pollutant, catalyst concentration and initial pH of the solution. Two experimental designs were performed for commercial catalysts ZnO and TiO2. The purpose was to find the best condition to promote the nicotine degradation in water. Other catalysts prepared from industrial and laboratory waste were tested under the optimized conditions. Analytical method used to quantify nicotine and its degradation products in all samples was high performance liquid chromatography. Experimental results showed that nicotine degradation by heterogeneous photocatalysis is a very efficient process. In both designs, initial pH was the most significant variable which has a strong positive effect. Initial nicotine concentration showed a negative effect, and catalyst concentration exhibited an optimal value for both commercial catalysts: 0,91 g.L-1 using ZnO, and 1,20 g.L-1 with TiO2. At the best conditions, about 98% of the molecule was degraded using ZnO and 88% with TiO2. Photocatalytic nicotine degradation followed a pseudo first order kinetic until 60 minutes of reaction for both commercial catalysts. Among the non-conventional catalysts tested, the one prepared from a petrochemical industry residue exhibited the highest photocatalytic degradation, about 43%.

CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / O objetivo deste trabalho foi desenvolver formulaÃÃes de pÃes tipo forma processados com os ingredientes funcionais: polidextrose, tomate, brÃcolis e aÃaà em pà e estudar o processo de obtenÃÃo atravÃs da tecnologia de massas congeladas, avaliando o efeito da estocagem congelada por 60 dias nos parÃmetros de qualidade dos pÃes. Aplicou-se trÃs Delineamento Composto Central Rotacional (DCCR) para o desenvolvimento das formulaÃÃes. Foram utilizadas trÃs combinaÃÃes de ingredientes: polidextrose e tomate em pÃ; polidextrose e brÃcolis em pÃ; polidextrose e aÃaà em pÃ, sendo essas variÃveis independentes, incorporadas em nÃveis de 0-20%, baseado no peso total da farinha de trigo. O DCCR incluiu onze ensaios: quatro pontos fatoriais, quatro axiais e trÃs repetiÃÃes no ponto central. Os resultados do DCCR foram analisados atravÃs da Metodologia de SuperfÃcie de Resposta (MSR), tendo como variÃveis resposta o fator de expansÃo mÃximo das massas, volume especÃfico, densidade e Ãndice de expansÃo dos pÃes. Dois ensaios, de cada combinaÃÃo de ingredientes, que obtiveram os melhores resultados com relaÃÃo a estes parÃmetros foram escolhidos para o estudo de sua obtenÃÃo pela tecnologia de massas congeladas. Os efeitos do perÃodo de estocagem congelada (0, 15, 30, 45 e 60 dias) foram avaliados atravÃs dos valores mÃdios dos dados das caracterÃsticas de qualidade dos pÃes, onde foram avaliados o fator de expansÃo e volume produzido das massas, bem como o volume especÃfico, densidade, Ãndice de expansÃo, pH, acidez, colorimetria, estrutura do miolo, anÃlise de perfil de textura (TPA) e anÃlise sensorial. Para a avaliaÃÃo estatÃstica foi aplicada a anÃlise de variÃncia, teste de Tukey e anÃlise de regressÃo. Os resultados mostraram que a incorporaÃÃo dos ingredientes funcionais, em quantidades superiores a 10%, modificaram os parÃmetros de fator de expansÃo mÃximo, volume especÃfico, densidade e Ãndice de expansÃo dos pÃes, resultando em pÃes de qualidade inferior. O estudo da obtenÃÃo por massas congeladas foi realizado com sete formulaÃÃes (padrÃo, sem a adiÃÃo de ingredientes funcionais, T1 e T2, com 5% e 10% de polidextrose e tomate em pÃ, respectivamente, B1 e B2, com 5% e 10% de polidextrose e brÃcolis em pà e A1 e A2, contendo 5% e 10% de polidextrose e aÃaà em pÃ. O tempo de estocagem congelada promoveu a reduÃÃo das cÃlulas viÃveis de levedura, esta reduÃÃo foi menor nos pÃes com ingredientes funcionais, que preservaram maior nÃmero de cÃlulas apÃs 60 dias de estocagem congelada, quando comparados à formulaÃÃo padrÃo. A estocagem congelada reduziu o fator de expansÃo e volume produzido das massas, assim como o volume especÃfico e Ãndice de expansÃo dos pÃes e aumentou a densidade. Houve aumento da luminosidade dos pÃes com ingredientes funcionais e reduÃÃo da cromaticidade, o que pode ser relacionado com a degradaÃÃo de pigmentos. O teor de umidade total das massas apresentou reduÃÃo significativa (p≤0,05), bem como o nÃmero de alvÃolos e a sua circularidade. Houve aumento da Ãrea e perimetro. Para os parÃmetros de textura, houve elevaÃÃo da dureza, gomosidade, mastigabilidade e coesividade, o que influenciou o decrÃscimo dos atributos sensoriais em funÃÃo do tempo de estocagem. Concluiu-se que o tempo de estocagem congelada atà 60 dias diminui as caracterÃsticas de qualidade dos pÃes, entretanto, este efeito foi menor nos pÃes incorporados com os ingredientes funcionais, devido à maior preservaÃÃo das cÃlulas viÃveis de levedura, apresentando qualidade superior aos pÃes processados sem a adiÃÃo dos ingredientes funcionais. / The aim of this study was to develop formulations of breads type processed form with functional ingredients polydextrose, tomatoes, broccoli and acai powder and study its getting through the frozen mass technology, evaluating the effect of frozen storage for 60 days in quality parameters breads. It was applied three a central composite design (CCRD) for the development of formulations. Three combinations of ingredients were used: polydextrose and broccoli powder, tomato powder and polydextrose polydextrose and acai powder, and these independent variables incorporated at levels of 0-20 % (flour basis). The CCRD included eleven trials : four factorial points , four axial and three replicates at the center point. The results of the CCRD were analyzed by Response Surface Methodology (RSM), with the response variable the factor of maximum expansion of the masses, specific volume, density and rate of expansion of the loaves. Two trials of each combination of ingredients , which achieved the best results with respect to these parameters were chosen for the study of obtaining the frozen dough technology. The effect of frozen storage period (0, 15, 30, 45 and 60 days) was evaluated through the average data values of the quality characteristics of bread, which we assessed the factor of expansion and production volume of the masses as well as the specific volume, density, expansion ratio, pH, acidity, colorimetry, crumb structure, texture profile analysis (TPA) and sensory analysis. For statistical analysis we used variance analysis, Tukey test and regression analysis was applied. The results showed that the incorporation of the functional parameters altered ingredients maximum expansion factor , specific volume, density, and expansion ratio of the loaves, damaging them in quantities up to 30 g. The study of obtaining frozen dough was held for seven formulations (standard, without adding functional ingredients , T1 and T2, with 5 to 10% polydextrose and tomato powder, respectively, B1 and B2, 5 to 10%, polydextrose and broccoli powder and A1 and A2, containing 5% to 10% polydextrose and acai powder. Generally, the time for frozen storage promoted the reduction of viable yeast cells, this reduction was less with the bread functional ingredients that have preserved greater number of cells after 60 days of frozen storage as compared to standard formulation. frozen storage expansion factor reduced the production volume and the mass and the specific volume expansion ratio and breads and enhanced density. was increased brightness of the loaves with functional ingredients and reduced chromaticity. Total moisture content of the mass showed a significant reduction (p≤0.05), and the number of alveoli and its circularity. Was increased the area and perimeter. For texture parameters, there was an increase in hardness, gumminess, chewiness and cohesiveness, which influenced the decrease of sensory attributes as a function of storage time. was concluded that the time of frozen storage was damaging the quality of breads however, this harmful effect was smaller breads incorporated with functional ingredients, due to greater preservation of viable yeast cells.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2016-09-01T14:42:20Z No. of bitstreams: 2 Dissertação - Danielle Pires Nogueira - 2016.pdf: 2016091 bytes, checksum: eb50931397d77906f88aaeec4a5fa5d0 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-09-01T14:42:33Z (GMT) No. of bitstreams: 2 Dissertação - Danielle Pires Nogueira - 2016.pdf: 2016091 bytes, checksum: eb50931397d77906f88aaeec4a5fa5d0 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-09-01T14:42:33Z (GMT). No. of bitstreams: 2 Dissertação - Danielle Pires Nogueira - 2016.pdf: 2016091 bytes, checksum: eb50931397d77906f88aaeec4a5fa5d0 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-04-18 / Due to the recent research for new fuels from renewable sources ethanol has been gaining momentum, because it can be produced from diverse raw materials, such as agro-industrial residues. The objective with this work was to study the production of reducing sugar by dilute acid, and enzymatic hydrolysis of the orange bagasse from juice industry. The orange bagasse was collected, cut into pieces, and crushed. Granulometry, and the contents of moisture, ashes, holocellulose, cellulose, hemicelulose, soluble and insoluble lignin were determined. The pre-treatment was done with calcium hydroxide following what was previously tested by Silva et al. (2013). A pre-test of the enzymes combination was done using 2 g of pre-treated biomass, in dry base, using 3 FPU/mL of cellulase, and 0 U/g and 3 U/g of xylanase. For the hydrolysis two central composite factorial 2³ designs were done, with the answer in total reducing sugars (ART). For the dilute acid hydrolysis the factors were HCl concentration, temperature, and time, and for the enzymatic the concentrations of cellulase and xylanase and time. The granulometry showed that 47.75% of the biomass with diameter over 0.833 mm, 32.84% of the biomass with an average diameter of 0.564 mm, and 19.41% of the biomass with diameter under 0.295 mm. The moisture content prior to drying was 84.69% and 7.38%, the ashes content was 3.79%. The cellulose content was 22.90% and the hemicellulose was 3.39%. The lignin content was 9.90%. The reducing sugar results for the acid hydrolysis varied from 9.32±0.68 mg ART per g of biomass to 30.15±0.31 mg ART per g biomass, the most significant factor was temperature, and the least was time. It was not possible to find the optimum region with the studied factors. The reducing sugar results for the enzymatic hydrolysis varied from 75.33±3.82 mg ART per g biomass to 99.66±0.62 mg ART per g biomass, the most significant factor was the cellulase concentration, and the least significant the xylanase concentration. The studied factors did not show the optimum region to maximize the reducing sugars content. The enzymatic hydrolysis produced larger concentrations of reducing sugars than the acid hydrolysis. / Frente as recentes buscas por novos combustíveis de fontes renováveis o etanol de segunda geração tem ganhado força, por poder ser produzido a partir de diversas matérias primas lignocelulósicas, como os resíduos agroindustriais. Objetivou-se com este trabalho estudar a geração de açúcares redutores por hidrólises ácida diluída e enzimática do bagaço de laranja proveniente da indústria de suco. O bagaço de laranja foi coletado, cortado, seco e moído. Granulometria, umidade, cinzas, concentrações de holocelulose, celulose, hemicelulose e lignina solúvel e insolúvel foram determinadas. O pré-tratamento foi realizado com hidróxido de cálcio de acordo com o previamente testado por Silva et al. (2013). Foi realizado um pré-teste da combinação das enzimas. Para as hidrólises foram feitos dois planejamentos fatoriais do tipo composto central 2³, com resposta em açúcares redutores totais (ART). Para a hidrólise ácida diluída os fatores estudados foram concentração de HCl, temperatura e tempo de hidrólise, na enzimática as concentrações de celulase e hemicelulase e o tempo. Na análise granulométrica encontrou-se 47,75% da biomassa com diâmetro superior a 0,833 mm, 32,84% de biomassa com diâmetro médio de 0,564 mm e 19,41% com diâmetro inferior a 0,295 mm. A umidade da biomassa antes da secagem foi de 84,69%, depois da secagem de 7,38% e as cinzas 3,79%. O conteúdo de celulose foi de 22,90% e o de hemicelulose 3,39%. O conteúdo de lignina foi de 9,90%. Houve uma perda de massa média de 30,03% no pré-tratamento. O pré-teste indicou um efeito positivo na combinação das enzimas para geração de açúcares redutores. Os resultados de açúcares redutores da hidrólise ácida variaram de 9,32±0,68 mg ART por g de biomassa a 30,15±0,31 mg ART por g biomassa, o fator mais significativo foi a temperatura e o menos o tempo, não foi possível encontrar a região ótima com os fatores estudados. Os resultados de açúcares redutores da hidrólise enzimática variaram de 75,33±3,82 mg ART por g biomassa a 99,66±0,62 mg ART por g biomassa, o fator mais significativo foi a concentração de celulase e o menos a concentração de xilanase. Com os fatores estudados não foi possível encontrar a região ótima de geração de açúcares redutores. A hidrólise enzimática gerou maiores concentrações de açúcares redutores que a hidrólise ácida.

O presente trabalho estuda a degradação fotocatalítica da nicotina em solução aquosa, um alcaloide altamente tóxico que tem sido detectado em efluentes, águas subterrâneas e água mineral. Os experimentos foram realizados em um reator batelada sob irradiação ultravioleta, tendo sido avaliadas três principais variáveis: concentração inicial do contaminante, concentração de catalisador e pH inicial da solução. Foram realizados dois planejamentos de experimentos para os catalisadores comerciais ZnO e TiO2, com o objetivo de encontrar a melhor condição para promover a degradação da nicotina em água. Outros catalisadores, preparados a partir de resíduos industriais e laboratoriais, foram testados nas condições otimizadas. O método analítico empregado para quantificar a nicotina nas amostras foi a cromatografia líquida de alta eficiência, o que permitiu registrar a formação de intermediários e subprodutos de reação. Os resultados experimentais demostraram que a degradação da nicotina por fotocatálise heterogênea é um processo bastante eficiente. Em ambos os planejamentos, o pH foi a variável que exerceu o maior efeito sobre a degradação, sendo este fortemente positivo. Já a concentração inicial de nicotina exerceu efeito negativo sobre a resposta e a concentração de catalisador em suspensão exibiu um ponto ótimo, que correspondeu a 0,91 g.L-1 para o ZnO, e 1,20 g.L-1 para o TiO2. Ensaios foram realizados nas condições otimizadas encontradas, onde cerca de 98% da molécula foi degradada utilizando ZnO em suspensão e 88% empregando TiO2, em uma hora de reação. A degradação fotocatalítica da nicotina demonstrou seguir uma cinética de pseudoprimeira ordem dentro do tempo de reação de 60 minutos, para os dois catalisadores comerciais. Entre os catalisadores não convencionais que foram testados, aquele que demonstrou o maior percentual de degradação foi obtido a partir de resíduo de uma indústria petroquímica, cerca de 43%. / The present work studies the photocatalytic degradation of nicotine in aqueous solution. This alkaloid is highly toxic and it has been detected in wastewater, groundwater and mineral water. The experiments were performed in a batch reactor under ultraviolet radiation. Three main variables of process were evaluated: initial concentration of pollutant, catalyst concentration and initial pH of the solution. Two experimental designs were performed for commercial catalysts ZnO and TiO2. The purpose was to find the best condition to promote the nicotine degradation in water. Other catalysts prepared from industrial and laboratory waste were tested under the optimized conditions. Analytical method used to quantify nicotine and its degradation products in all samples was high performance liquid chromatography. Experimental results showed that nicotine degradation by heterogeneous photocatalysis is a very efficient process. In both designs, initial pH was the most significant variable which has a strong positive effect. Initial nicotine concentration showed a negative effect, and catalyst concentration exhibited an optimal value for both commercial catalysts: 0,91 g.L-1 using ZnO, and 1,20 g.L-1 with TiO2. At the best conditions, about 98% of the molecule was degraded using ZnO and 88% with TiO2. Photocatalytic nicotine degradation followed a pseudo first order kinetic until 60 minutes of reaction for both commercial catalysts. Among the non-conventional catalysts tested, the one prepared from a petrochemical industry residue exhibited the highest photocatalytic degradation, about 43%.