Condition-Based Maintenance (CBM) and Prognostics and Health Management (PHM) technologies aim at improving the availability, reliability, maintainability, and safety of systems through the development of fault diagnostic and failure prognostic algorithms. In complex engineering systems, such as aircraft, power plants, etc., the prognostic activities have been limited to the component-level, primarily due to the complexity of large-scale engineering systems. However, the output of these prognostic algorithms can be practically useful for the system managers, operators, or maintenance personnel, only if it helps them in making decisions, which are based on system-level parameters. Therefore, there is an emerging need to build health assessment methodologies at the system-level. This research employs techniques from the field of design-of-experiments to build response surface metamodels at the system-level that are built on the foundations provided by component-level damage models.

The physiological benefits of flaxseed against pathological disturbances, such as cancers and heart diseases, are mainly attributed to its high lignan content. This study (Experiment 1) examined the application of pressurized low polarity water (PLPW) for extraction of lignans, proteins and carbohydrates from defatted flaxseed meal. Key processing conditions included temperature (130, 160, 190°C), solvent pH (4, 6.5 and 9), solvent to solid ratio (S/S) (90, 150 and 210 mL/g) and introduction of co-packing material (0 and 3 g glass beads). The addition of 3 g glass beads as co-packing material facilitated extraction by enhancing surface contact between the liquid and solid thus shortening extraction time. Elevated temperature accelerated the extraction rate by increasing the solid diffusion coefficient thereby reducing the extraction time. The maximum yield of lignans (99 %) was obtained at temperatures ranging from 160°C to 190°C, with solvent volume of 180 mL (90 mL/g meal) at pH 9. Optimal conditions for protein extraction (70 %) were pH 9, extraction volume of 420 mL (210 mL/g meal) and 160°C. Total carbohydrates yield was maximized at 50% recovery at pH 4 and 160°C with 420 mL solvent (210 mL/g meal). Increased temperature accelerated extraction, thus reducing solvent volume and time to reach equilibrium. For the extraction of proteins, however, a temperature of 130-160°C is recommended, as proteins are vulnerable to thermal degradation due to heat decomposition. The effects of flow rate and geometric dimensions for extraction of lignans and other flaxseed meal bioactives were further investigated in Experiment 2, based on the variables optimized in the previous experiment. Defatted flaxseed meal was extracted with pH 9 buffered water with meal to co-packing glass beads ratio of 1:1.5 at 5.2 MPa (750 psi) and 180°C. The aqueous extracts were analyzed for lignan, protein and carbohydrate using HPLC and colorimetric methods. The optimal extraction yields for lignan, protein and carbohydrate were found at flow rates of 1 to 2 mL/min with bed depth between 20 and 26 cm and a S/S ratio of 40 to 100 mL/g. The combination of low flow rate and high bed depth allowed the use of lower S/S ratio with reduced total solvent volume consumption. This study also evaluated the mass transfer kinetics governing the process of lignan extraction from flaxseed meal in a fixed bed extraction cell. Diffusion of solute into the continuously flowing solvent was mainly responsible for the mass transfer mechanism as flow rate did not increase proportionally with the yield and rate of extraction. The extraction kinetics were studied on the basis of two approaches: Fick’s diffusion equation and a two-site exponential kinetic model. The proposed two-site exponential kinetic model corresponding to the two-stage extraction (rapid and slow phases) successfully described the experimental data. Diffusivities attained from Fick’s diffusion model ranged from 2 x 10-13 to 9 x 10-13 m2s-1 while mass transfer coefficients were between 4.5 x 10-8 and 2.3 x 10-7 ms-1 for extraction of lignans at 180°C, pH 9 with 1:1.5 meal to co-packing material ratio.

The physiological benefits of flaxseed against pathological disturbances, such as cancers and heart diseases, are mainly attributed to its high lignan content. This study (Experiment 1) examined the application of pressurized low polarity water (PLPW) for extraction of lignans, proteins and carbohydrates from defatted flaxseed meal. Key processing conditions included temperature (130, 160, 190°C), solvent pH (4, 6.5 and 9), solvent to solid ratio (S/S) (90, 150 and 210 mL/g) and introduction of co-packing material (0 and 3 g glass beads). The addition of 3 g glass beads as co-packing material facilitated extraction by enhancing surface contact between the liquid and solid thus shortening extraction time. Elevated temperature accelerated the extraction rate by increasing the solid diffusion coefficient thereby reducing the extraction time. The maximum yield of lignans (99 %) was obtained at temperatures ranging from 160°C to 190°C, with solvent volume of 180 mL (90 mL/g meal) at pH 9. Optimal conditions for protein extraction (70 %) were pH 9, extraction volume of 420 mL (210 mL/g meal) and 160°C. Total carbohydrates yield was maximized at 50% recovery at pH 4 and 160°C with 420 mL solvent (210 mL/g meal). Increased temperature accelerated extraction, thus reducing solvent volume and time to reach equilibrium. For the extraction of proteins, however, a temperature of 130-160°C is recommended, as proteins are vulnerable to thermal degradation due to heat decomposition. The effects of flow rate and geometric dimensions for extraction of lignans and other flaxseed meal bioactives were further investigated in Experiment 2, based on the variables optimized in the previous experiment. Defatted flaxseed meal was extracted with pH 9 buffered water with meal to co-packing glass beads ratio of 1:1.5 at 5.2 MPa (750 psi) and 180°C. The aqueous extracts were analyzed for lignan, protein and carbohydrate using HPLC and colorimetric methods. The optimal extraction yields for lignan, protein and carbohydrate were found at flow rates of 1 to 2 mL/min with bed depth between 20 and 26 cm and a S/S ratio of 40 to 100 mL/g. The combination of low flow rate and high bed depth allowed the use of lower S/S ratio with reduced total solvent volume consumption. This study also evaluated the mass transfer kinetics governing the process of lignan extraction from flaxseed meal in a fixed bed extraction cell. Diffusion of solute into the continuously flowing solvent was mainly responsible for the mass transfer mechanism as flow rate did not increase proportionally with the yield and rate of extraction. The extraction kinetics were studied on the basis of two approaches: Fick’s diffusion equation and a two-site exponential kinetic model. The proposed two-site exponential kinetic model corresponding to the two-stage extraction (rapid and slow phases) successfully described the experimental data. Diffusivities attained from Fick’s diffusion model ranged from 2 x 10-13 to 9 x 10-13 m2s-1 while mass transfer coefficients were between 4.5 x 10-8 and 2.3 x 10-7 ms-1 for extraction of lignans at 180°C, pH 9 with 1:1.5 meal to co-packing material ratio.

This thesis illustrates parameter optimization of compressive strength, flexural strength and impact resistance of steel fiber reinforced high strength concrete (SFRHSC) by statistical design and analysis of experiments. Among several factors affecting the compressive strength, flexural strength and impact resistance of SFRHSC, five parameters that maximize all of the responses have been chosen as the most important ones as age of testing, binder type, binder amount, curing type and steel fiber volume fraction. Taguchi and regression analysis techniques have been used to evaluate L27(313) Taguchi&amp / #65533 / s orthogonal array and 3421 full factorial experimental design results. Signal to noise ratio transformation and ANOVA have been applied to the results of experiments in Taguchi analysis. Response surface methodology has been employed to optimize the best regression model selected for all the three responses. In this study Charpy Impact Test, which is a different kind of impact test, have been applied to SFRHSC for the first time. The mean of compressive strength, flexural strength and impact resistance have been observed as around 125 MPa, 14.5 MPa and 9.5 kgf.m respectively which are very close to the desired values. Moreover, this study is unique in the sense that the derived models enable the identification of underlying primary factors and their interactions that influence the modeled responses of steel fiber reinforced high strength concrete.

Thesis (MComm)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Work Engagement is one construct of many that forms part of the complex nomological network of constructs underlying the behaviour of working man2. Work Engagement is an important construct both from an individual as well as from an organisational perspective. Human resource management interventions aimed at enhancing Work Engagement aspire to contribute to the achievement of the organisation’s primary objective and the well-being of the organisation’s employees. Such interventions will most likely also be valued by individuals within the workplace, as individuals will be able to experience a sense of personal fulfilment through self-expression at work. It is therefore essential to gain a valid understanding of the Work Engagement construct and the psychological mechanism that underpins it, in order to design human resource interventions that will successfully enhance Work Engagement. The current study raises the question why variance in Work Engagement exists amongst different employees working in different organisational contexts. The research objective of the current study is to develop and empirically test an explanatory Work Engagement structural model that will provide a valid answer to this question. In this study, a comprehensive Work Engagement structural model was proposed. An ex post facto correlational design with structural equation modelling (SEM) as the statistical analysis technique was used to test the substantive research hypotheses as represented by the Work Engagement structural model. Furthermore, the current study tested two additional narrow-focus structural models describing the impact of value congruence on Work Engagement by using an ex post facto correlational design with polynomial regression as the statistical analysis technique. A convenience sample of 227 teachers working in public sector schools falling under the jurisdiction of the Western Cape Education Department (WCED) participated in the study. The comprehensive Work Engagement model achieved reasonable close fit. Support was found for all of the hypothesised theoretical relationships in the Work Engagement structural model, except for the influence of the PsyCap*Job Characteristics interaction effect on Meaningfulness and for three of the five latent polynomial regression terms added in the model in an attempt to derive response surface test values. The response surface analyses findings were mixed. Based on the obtained results, meaningful practical recommendations were derived. / AFRIKAANSE OPSOMMING: Werkverbintenis1 is een van ‘n groot verskeidenheid konstrukte wat deel vorm van die komplekse nomologiese netwerk van konstrukte wat die gedrag van die arbeidende mens onderlê. Werkverbintenis word as ‘n belangrike konstruk beskou vanuit ‘n individuele sowel as vanuit ‘n organisatoriese perspektief. Menslike hulpbronbestuurs-intervensies gerig op die bevordering van Werkverbintenis streef daarna om by te dra tot die bereiking van die organisasie se primêre doel sowel as tot die welstand van die organisasie se werknemers. Sodanige intervensies sal waarskynlik ook deur werknemers waardeer word, aangesien sodanige intervensies die kanse verhoog dat individue selfvervulling in hul werk sal ervaar omdat die werk hul die geleentheid bied om hulself in hul werk uit te leef. Dit is gevolglik noodsaaklik om ‘n geldige begrip te ontwikkel van die Werkverbintenis-konstruk en die sielkundige meganisme wat dit onderlê ten einde menslike hulpronbestuurs-intervensies te ontwerp wat suksesvol Werkverbintenis sal bevorder. Die huidige studie stel die vraag aan die orde waarom variansie in Werkverbintenis tussen verskillende werknemers bestaan wat in verskillende organisatoriese kontekste werk. Die navorsingsdoelstelling van die huidige studie is om ‘n verklarende Werkverbintenisstrukturele model te ontwikkel en te toets wat ‘n geldige antwoord op hierdie vraag sal bied. ‘n Omvattende Werkverbintenis strukturele model is in hierdie studie voorgestel. ‘n Ex post facto korrelatiewe ontwerp met strukturele vergelykingsmodellering (SVM) as die statistiese ontledingstegniek is gebruik om die substantiewe navorsingshipotese soos voorgestel deur die Werkverbintenis strukturele model te toets. Die huidige studie het voorts twee addisionele nouer-fokus strukturele modelle getoets wat die impak van waardekongruensie op Werkverbintenis beskryf deur middel van ‘n ex post facto korrelatiewe ontwerp met polinomiese regressie-ontleding as statistiese ontledingstegniek. ‘n Geriefsteekproef van 227 onderwysers wat in openbare skole werksaam is wat onder die beheer van die Wes Kaapse Department van Onderwys val (WKDO) het aan die studie deelgeneem. Die omvattende Werkverbintenis-model het redelik goeie pasgehalte getoon. Steun is gevind vir all die voorgestelde teoretiese verwantskappe in die Werkverbintenis strukturele model, behalwe vir die invloed van die Sielkundige kapitaal*Werk eienskappe-interaksie-effek op Betekenisvolheid en vir drie van die vyf polinomiese latente regressie-terme wat in die model ingesluit is in ‘n poging om responsoppervlakte-waardes af te lei. Gemengde resultate is verkry vir die responsoppervlakte-ontleding. Betekenisvolle praktiese aanbevelings is gemaak op grond van die navorsingsresultate.

Made available in DSpace on 2015-04-17T14:49:14Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1368291 bytes, checksum: c9504d31896cd49c514d45cee104f03b (MD5) Previous issue date: 2011-09-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The objective of the present work was to produce pineapple stem raisin by means of osmo-solar drying. The raw material was selected taking into account parameters such as: color of the rind and level of soluble solids from the fruits. A type 23 factorial design was preceded with 4 repetitions at the central point, for further optimization of the osmotic dehydration using the methodology of surface responses. The partially dry product obtained from the osmotic dehydration, utilizing as conditions the ones from the planning, passed through complementary sun drying by means of a solar drier, build with assessable materials such as joined wood, aluminum plates, glass boards, matte black paint, Styrofoam and coal. The raw material, the product partially dehydrated and the final product had their compositions analyzed. The evaluation of the dimensions of the pineapples showed little variation, with a CV < 10%, an important factor for the standardization and control of the industrial processes. The raw material also presented a high level of soluble solids and low level of acidity, proving the analyzed pineapple useful for in natura consumption and for the industrial processing of several products, among them alcoholic and non-alcoholic beverages. Furthermore, the raw material has proven to be an excellent source of vitamin C, with a concentration of such nutrient higher than what is daily recommend according to legislation. The adopted linear factors have presented themselves to be adequate, they were fairly adjusted and predictive for the loss of (PA) and weight loss (PP) and fairly adjusted and predictive to gain of solids and gain of solid-loss of water ratio (GS:PA). Analyzing the level curves and surface of answer of the optimization parameters GS:PA, built from the statistical models, it was determined the ideal conditions of osmotic dehydration which were: T = 50 ºC, C = 40 g 100 g-1 and F:SO= 3:20. In evaluation, the Sun dryer presented and average temperature of 41.2 ºC against 35.7 ºC of natural air and maximum temperature of 46 ºC, besides the minimal relative air humidity of 37%. The product obtained after the draught presented humidity of 13.70 g 100 g-1 obeying the legislation concerning the maximum levels of humidity for dehydrated fruit. / O objetivo deste trabalho foi produzir passas de talo de abacaxi pérola por processo de secagem combinado osmo-solar. Selecionou-se a matéria-prima levando em consideração parâmetros como: cor da casca e teor de sólidos solúveis da fruta. Procedeu-se um planejamento fatorial do tipo 23 com 4 repetições no ponto central, para posterior otimização de desidratação osmótica usando a metodologia de superfícies de resposta. O produto parcialmente seco obtido a partir da desidratação osmótica, utilizando-se como condições às obtidas no planejamento, passou por secagem solar complementar em secador solar, construído com materiais acessíveis, tais como: madeira compensada, folhas de alumínio, placas de vidro, esmalte sintético preto fosco, isopor e carvão. A matéria-prima, o produto parcialmente desidratação e o produto final, tiveram a sua composição analisada. A avaliação das dimensões dos abacaxis mostrou pequena variação, com CV < 10%, fator importante para a padronização e controle de processos industriais. A matériaprima ainda apresentou alto teor de sólidos solúveis e baixo teor de acidez, fazendo o abacaxi analisado propício para o consumo in natura e para o processamento industrial de diversos produtos, entre eles: bebidas alcoólicas e não-alcoólicas. Além disso, a matéria-prima mostrou-se excelente fonte de vitamina C, com concentração deste nutriente superior à sua recomendação diária, preconizada pela legislação. Os modelos lineares adotados apresentaram-se adequados, sendo bastante ajustados e preditivos para a perda de água (PA) e perda de peso (PP) e razoavelmente ajustados e preditivos para o ganho de sólidos e razão ganho de sólidos-perda de água (GS:PA). Analisando-se as curvas de nível e superfície de resposta do parâmetro de otimização GS:PA, construídos a partir dos modelos estatísticos, determinaram-se as condições ideais de desidratação osmótica que foram: T = 50 ºC, C = 40 g 100 g-1 e F:SO= 3:20. Em avaliação, o secador solar apresentou temperatura média de 41,2 ºC contra 35,7 ºC do ar ambiente e temperatura máxima de 46 ºC, além de umidade relativa mínima do ar secagem de 37%. O produto obtido após a secagem apresentou umidade de 13,70 g 100 g-1 atendendo o a legislação quanto ao teor máximo de umidade para fruta desidratada.

Destacam-se as semelhanças entre os nutrientes boro (B) e cálcio (Ca) quanto às formas e as funções que eles exercem nos vegetais. Partindo do princípio que a interação Ca - B afeta os atributos morfológicos, ultraestruturais e bioquímicos, bem como a nodulação nas plantas leguminosas, objetivou-se com esse estudo determinar a relação Ca:B mais adequada para a produção de grãos e matéria seca de soja, bem como avaliar os efeitos da interação B e Ca na fixação biológica de N2 (atividade da nitrogenase -N-ase [EC 1.18.6.1]), na morfologia de raízes (comprimento e superfície total), anatomia de raízes (nódulos) e de folhas, assim como as avaliações ultraestruturais dos mesófilos foliares, rendimento do teor de óleo nos grãos das plantas de soja (cultivar BRS 284), crescidas em solução nutritiva. Foram avaliadas ainda a produção de massa seca das plantas, as concentrações e os acúmulos de Ca, B, Mg, K e N na parte aérea e raízes. Foi empregado um esquema fatorial 5² incompleto, perfazendo treze combinações de doses de Ca (mmol L-1) e B (µmol L-1), as quais foram distribuídas segundo o delineamento experimental de blocos ao acaso, com quatro repetições. As maiores atividades da N-ase foram obtidas com as maiores doses de Ca e B (7,25 mmol L-1 de Ca e 50 µmol L-1 de B). A menor dose de Ca resultou na inibição da N-ase em cerca de 90%. Os maiores comprimentos e superfícies totais de raízes foram obtidos na combinação de doses de 7,25Ca e 12,5B, enquanto que para a combinação das menores doses de Ca e B observou-se uma redução de cerca de 70% e 60% para comprimento e superficial de raízes, respectivamente. A maior produção de biomassa seca das plantas e de grãos, os maiores acúmulos de Ca, B, N, K e Mg nas folhas e o maior rendimento de óleo foram obtidos com o fornecimento de 4,25 mmol L-1 de Ca e 12,5 µmol L-1 de B, observando-se relação Ca:B na solução nutritiva próxima de 350:1 e nas folhas de 700:1. O teor de óleo nos grãos incrementou cerca de 20% com o aumento das doses de B de 3,125 para 50 µmol L 1. O número de camadas de células do córtex dos nódulos aumentou com o incremento das concentrações de Ca e B na solução. Observou-se ruptura da membrana dos cloroplastos no mesófilo foliar e elevado número de bactérias fixadoras de N2 penetrando o interior dos tecidos nodulares quando as plantas foram submetidas ao menor suprimento de Ca e maior de B. A combinação da menor dose de B junto a maior dose de Ca provocou ruptura da parede celular e o espessamento da lamela média das folhas. O aumento no fornecimento de Ca ameniza os efeitos negativos do baixo suprimento de B na produção de biomassa das plantas e de grãos, no comprimento e superfície de raízes e na atividade da nitrogenase. A relação Ca:B, tanto na solução, quanto no tecido vegetal, não pode ser entendida como parâmetro exclusivo de equilíbrio nutricional / Regarding mineral nutrition of plants, we highlight the similarities between nutrients boron (B) and calcium (Ca) in relation to similar functions they play in plant physiology. However, the mechanisms involved in the interaction between these nutrients are not very well known. Assuming that the interaction Ca - B affects the morphological, ultrastructural and biochemical attributes, as well as the nodulation in leguminous plants, the objective with this study was to determine the optimum Ca:B ratio, in the solution and plan tissue as well for dry matter yield of grain and dry matter of soybean, and to evaluate the effects of B - Ca interaction in the biological N2 fixation (nitrogenase activity - N-ase [EC 1.18.6.1]), root morphology (total root length and total root surface area), root anatomy (nodules), as well as in the ultrastructural evaluation of foliar mesophilic, and yield of oil content of soybean (cultivar BRS 284), grown in nutrient solution. Dry matter yield of plants, Ca-concentrations and amounts of Ca, B, Mg, K and N in shoots and roots were also evaluated. The experimental arrange used was an incomplete 5² factorial, making thirteen combinations of Ca (mmol L-1) and B (µmol L-1) rates, which were set in a randomized block design, with four replications. The highest N-ase activity was obtained with the highest doses of Ca and B (7,25 mmol L-1 of Ca and 50 µmol L-1 of B). The lowest Ca rate resulted in approximately 90% inhibition of N-ase. The highest total root length and total root surface area were obtained with combination of 7,25Ca and 12,5B rates, whereas the combination of the lowest Ca and B rates caused reduction of approximately 70% and 60% on root length and area, respectively. The highest dry matter and grain yield, highest accumulations of Ca, B, N, K and Mg on the leaves and the highest oil content in grains were obtained when 4,25 mmol L-1 of Ca and 12,5 µmol L-1 of B were supplied, resulting in a Ca:B ratio of approximately 350:1 on nutrient solution and 700:1 on leaves. The oil content in grains raised about 20% increasing B rates from 3,125 to 50 µmol L-1. The number of cell layers of nodule cortex raised with increasing Ca and B levels in the solution. It was observed membrane rupture of chloroplasts in leaf mesophyll and high number of N2-fixing bacteria entering the interior of nodular tissues when plants were supplied with the lowest Ca rate (1,75Ca) and the highest B (50B). The combination of the lowest B rate (3,125B) and the highest Ca rate (7,25) caused cell wall rupture and thickening of the middle lamella on the leaves. The increase of Ca levels on the solution mitigates the negative effects of the low B supply in plant biomass and grain yield, in root length and root surface area and in N-ase activity. The Ca:B ratio either in the solution or plant tissue, cannot be understood as an exclusive parameter of nutritional status

Conselho Nacional de Desenvolvimento Científico e Tecnológico / The so called amination water (AW), an effluent stream from the industrial production of the trifluraline herbicide, toxic and recalcitrant to conventional treatments such as the microbiological, was submitted to a combined advanced process. For the degradation study of this effluent a recent, promising alternative was chosen - the potassium ferrate (K2FeO4) oxidation-coagulation - that demonstrates high oxidant capability (from 2.2 up to 0.72 V) in a large pH range. In this study, a response surface methodology (RSM) design using pH and K2FeO4 concentration as independent variables, and the absorptiometric color reduction as a dependent one, was applied. The resultant regression equation for the quadratic model of the star design was nAbs (%) = 26.142 - 1.044A - 2.065A2 - 0.941B - 0.505B2 + 1.55AB. The second order results of the star design from the variance analysis (ANOVA) showed that the quadratic model is better than the lineal, and gave evidence that, a maximum of 29% absorptiometric color reduction occurs, when an initial pH of 7 and lower K2FeO4 concentration were used. By the same conditions, the reduction of the chemical oxygen demand (COD) was 49.5%. As the reduction of potassium ferrate generate ferric iron salts in aqueous solution, there is a great potential for its combined use as Fe(III) source for Fenton reagent, generating hydroxyl radicals (HO·) by addition of H2O2 to the reaction system. A new design based on RSM was applied, evaluating the potentiality of the oxidationcoagulation-Fenton like process having the pH, Fe(VI) -> Fe(III) and H2O2 as independent variables, and absorptiometric color reduction efficiency as evaluation responses for the dependent variable. The resulting regression equation for the quadratic model was nAbs (%) = 36.9 - 21.58A + 8.37A2 + 1.36B + 0.92B2 + 1.08C + 1.52C2 + 1.27AB - 1.34AC + 1.33BC. The ANOVA results evidenced that the maximum absorptiometric color reduction occurs by pH 3, and by correspondent 10 g L-1 de Fe(VI) and 20 g L-1 hydrogen peroxide. The absorptiometric color and COD reduction were 96% and 57%, respectively. An efficiency increase of the HO· radical generation was achieved when the previous process was combined to UV irradiation, carrying out the so called oxidation-coagulationphoto-Fenton like process. As before, a RSM was applied, where the pH, Fe(VI) -> Fe(III) concentration, H2O2 concentration and temperature were evaluated as independent variables. The efficiency of the absorptiometric color reduction was chosen as dependent variable. The resulting regression equation for the quadratic model was nAbs (%) = 38.3 - 20.2A + 8.12A2 - 0.27B + 3.73B2 + 0.3C + 3.6C2 + 1.67D + 3.1D2 + 1.72AB + 0.51AC - 1.82AD + 0.74BC - 1.11BD + 0.03CD. The ANOVA results evidenced that the maximum absorptiometric color reduction occurs by pH 3 and by 10 g L-1 de Fe(VI) and 20 g L-1 hydrogen peroxide amounts, at 60 °C. The maxima efficiencies achieved for the effluent stream treatment by the oxidationcoagulation-photo-Fenton process were 95% and 85%, for absorptiometric color and COD reduction, respectively. The high efficiency of the combined process as an oxidative-coagulant-oxidative pretreatment for posterior conventional process (e.g., microbiological treatment) can be looked out as an interesting and advantageous alternative for the AW treatment, as well as other recalcitrant streams. / A produção industrial do herbicida trifluralina gera a corrente efluente água de aminação (AA), tóxica e recalcitrante a processos convencionais, tais como o tratamento microbiológico. Para o estudo da degradação deste efluente escolheu-se uma recente e promissora alternativa para a degradação de biorecalcitrantes - a oxidação-coagulação com Ferrato de Potássio (K2FeO4) - que demonstra alto poder oxidante, de 2,2 a 0,72 V, em toda faixa de pH. Foi aplicado, também, neste estudo, a metodologia de planejamento com superfície de resposta (RSM), tendo-se como variáveis independentes, o pH e a concentração de K2FeO4; e como variável dependente, a remoção de cor. A equação de regressão resultante do planejamento estrela, para o modelo quadrático, é nAbs (%)= 26,142 - 1,044A - 2,065A2 - 0,941B - 0,505B2 + 1,55AB. Os resultados do modelo de superfície de resposta de segunda ordem, na forma de análise de variância (ANOVA), demonstraram que o modelo quadrático é superior ao modelo linear e evidenciaram que a máxima redução da cor absorciométrica (29%) ocorre com pH inicial 7 e com a menor concentração de ferrato de potássio utilizada. Da mesma forma, obteve-se redução da demanda química de oxigênio (DQO) de 49,5%. Como a redução do ferrato de potássio produz sais de Fe(III) em solução, aproveitouse a grande potencialidade para a combinação como fonte de íons férricos para o reagente Fenton, adicionando H2O2 para a geração de radicais hidroxil (HO·). Foi, então, aplicado um novo planejamento baseado em RSM, avaliando a potencialidade do processo de oxidaçãocoagulação-Fenton com as variáveis independentes pH, concentração de Fe(VI) -> Fe(III) e H2O2, e, como variável dependente para a avaliação dos resultados, a eficiência da redução da cor absorciométrica. A equação de regressão resultante deste planejamento, para o modelo quadrático, que se mostrou superior ao modelo linear é nAbs (%) = 36,9 - 21,58A + 8,37A2 + 1,36B + 0,92B2 + 1,08C + 1,52C2 + 1,27AB - 1,34AC + 1,33BC. Os resultados da análise ANOVA evidenciaram que a máxima redução da cor absorciométrica ocorre quando o pH inicial foi 3, usando-se 10g L-1 de Fe(VI) e 20 g L-1 peróxido de hidrogênio. Assim, se obteve ainda redução da cor absorciométrica da ordem de 96% e, da DQO, de 57%. Por ainda acreditar num aumento da eficiência da geração de radicais HO·, o processo anterior foi combinado à radiação UV, realizando-se então o chamado processo oxidaçãocoagulação-foto-Fenton e, como nos anteriores, através de RSM avaliaram-se as variáveis independentes, pH, concentração de Fe(VI) -> Fe(III), H2O2 e temperatura. Como variável dependente foi escolhida a redução da cor absorciométrica. A equação resultante para este planejamento, para o modelo quadrático, superior ao linear, é nAbs (%) = 38,3 - 20,2A + 8,12A2 - 0,27B + 3,73B2 + 0,3C + 3,6C2 + 1,67D + 3,1D2 + 1,72AB + 0,51AC - 1,82AD + 0,74BC - 1,11BD + 0,03CD. Os resultados da ANOVA demonstraram que a máxima redução ocorreu quando o pH inicial foi 3, usando-se 10 g L-1 de Fe(VI), 20 g L-1 peróxido de hidrogênio e temperatura de 60 °C. A máxima eficiência alcançada no tratamento do efluente AA pelo processo de oxidação-coagulação-foto-Fenton foi de 95% e, de 85%, para a cor absorciométrica e a DQO, respectivamente. A eficiência dos processos estudados, como pré-tratamento oxidativo-coagulanteoxidativo para posterior tratamento convencional (ex. microbiológico), pode ser interessante alternativa para o tratamento da corrente recalcitrante AA.

Submitted by Maike Costa (maiksebas@gmail.com) on 2017-09-05T11:30:32Z No. of bitstreams: 1 arquivototal.pdf: 2959046 bytes, checksum: a3f9f3b11f2ba3b9c5298a8b10c24c58 (MD5) / Made available in DSpace on 2017-09-05T11:30:33Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2959046 bytes, checksum: a3f9f3b11f2ba3b9c5298a8b10c24c58 (MD5) Previous issue date: 2017-02-17 / Caprine livestock is among the main economic activities in semi-arid region of Northeastern Brazil which is characterized by low rain rates and a dry weather, where caatinga biome represents the most important feed source for caprine herds. In this study, we evaluated the fatty acids and volatile compounds profiles as well as the sensorial properties of milk and cheese from caprines kept and raised under different systems in semi-arid Brazil, confined space and open pastures. An optimization of the extraction conditions for the volatile compounds in caprine milk was made by using Response Surface Methodology. From this statistical tool we could identify the best conditions to maximize the number of volatile compounds extracted, corresponding them to 15 minutes for equilibrium time, 30 minutes for extraction time and 45 °C for extraction temperature. Using these conditions, 19 different volatile compounds were identified. Amongst these compounds, octanoic acid (caprylic acid) and decanoic acid (capric acid) can be highlighted with having larger relative areas, and they are volatile fatty acids correlated to the characteristic flavor presented in caprine milk. The dairy caprines (Saanen and American Alpine) used were divided into two groups: Caprines fed in open pasture plus concentrate supplementation (OF) and those fed in confined space (CS) with hay and concentrate. Milk and cheese from animals fed in OF presented higher content of fatty acids for oleic acid (C18:1c9), stearic acid (C18:0), polyunsaturated (PUFA) and monounsaturated (MUFA), including C16:1c7 C16:1c9 e C17:1c9, isomers cis and trans of C18:1, linoleic acid (C18:2n6), linolenic acid (C18:3n3), arachidonic acid (C20:4n6), desired fatty acids (DFA) and higher PUFA/SFA and MUFA/SFA rates. Several volatile compounds found in milk and cheese from OF were not present in CS, such as the terpene compounds α-terpineol e β-caryophyllene. The milk from OS was described for having a more intense herbal flavor whereas the milk from CS was more intense in butter flavor and taste and showed a higher residual aftertaste. Regarding to the sensorial properties of the cheese, no differences were found between the two different systems, however, the overall acceptability was higher for milk and cheese from animals feed in OF. Our results suggest that raising caprines in open field can be considered the best production system to be used in semi-arid region of Northeastern Brazil as it valorizes the use of the native pasture found in Caatinga to feed caprine herds, being an interesting economic alternative for the local farmers. / A pecuária caprina é uma das principais atividades realizadas na região semiárida do Nordeste brasileiro. Essa região caracteriza-se por apresentar condições ambientais de terras áridas e de baixa pluviosidade, onde os caprinos têm no Bioma caatinga sua principal fonte alimentar. Neste estudo, avaliou-se o impacto do sistema de produção realizado na região semiárida brasileira sobre os perfis de ácidos graxos, voláteis e sensorial do leite e do queijo caprino. Inicialmente, foi realizada a otimização das condições de extração de compostos voláteis em leite caprino por meio da metodologia da superfície de resposta. A partir desta metodologia estatística, foi possível identificar as melhores condições para maximizar a variável resposta (número de compostos voláteis extraídos), correspondendo a 15 minutos para o tempo de equilíbrio, 30 minutos para o tempo de extração e 45 °C para a temperatura de extração. Utilizando estas condições, foram identificados 19 compostos voláteis diferentes, dentre os quais se destacaram o ácido octanóico (ácido caprílico) e ácido decanóico (ácido cáprico) com maiores áreas relativas. Em seguida, cabras leiteiras mestiças, Sannen e Alpina-americana, foram divididas, em delineamento inteiramente casualizado, em dois grupos: cabras alimentadas em sistema de pastagem mais a suplementação concentrada (SP), e aquelas alimentadas em sistema de confinamento (SC), com feno e concentrado. O leite e o queijo de animais alimentados em SP apresentaram maiores quantidades ácido oleico (C18:1c9), esteárico (C18:0), de poli-insaturados (PUFA) e monoinsaturados (MUFA) totais, incluindo os monoinsaturados C16:1c7 C16:1c9 e C17:1c9, os isômeros cis e trans de C18:1, o ácido linoleico (C18:2n6), linolênico (C18:3n3), araquidônico (C20:4n6), ácidos graxos desejáveis (DFA) e maior razão PUFA/SFA, MUFA/SFA. Alguns compostos voláteis estavam ausentes nos leites e queijos provenientes de animais de confinamento, destacando-se a presença de dois compostos terpênicos (α-terpineol e β-cariofileno), encontrados exclusivamente em leite e queijo de animais de pasto. O leite SP foi descrito com maior sabor herbáceo e o leite SC com maior aroma e sabor de manteiga e maior persistência residual. As variações entre os sistemas de produção não foram suficientes para promover diferenças perceptíveis nos atributos sensoriais dos queijos, mas, para o atributo aceitabilidade geral, tanto o leite quanto o queijo SP foram considerados mais aceitos pelos julgadores. Os resultados provenientes da execução deste estudo indicam que o melhor sistema de produção a ser realizado na região semiárida nordestina é o sistema desenvolvido na pastagem nativa com suplementação, pois valoriza a criação de caprinos leiteiros na Caatinga, tornando-se uma alternativa economicamente vantajosa para os produtores e processadores de leite de cabra.

Made available in DSpace on 2015-03-26T13:51:59Z (GMT). No. of bitstreams: 1 texto completo.pdf: 2800985 bytes, checksum: 40fca2e6fae55c6c55dc0ea1697df826 (MD5) Previous issue date: 2013-10-22 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / In pigmented microorganisms, carotenoids are pigments, precursors of vitamin A that provide protective effects against oxidative damage. Extrinsic environmental factors such as temperature, specific carbon sources and inducers of reactive oxygen species (ROS) such as hydrogen peroxide and light associated with physiological conditions (maximum exponential growth phase, early and late stationary phase) influence the accumulation of carotenoids in microbial cells. A pigmented yeast was isolated from an orchard in Universidade Federal de Viçosa, Minas Gerais, Brazil. The main aims were to identify the isolated yeast and analyze the influence of environmental (light, temperature and arabinose) and physiological conditions (log phase, early and late stationary phase) on the production of carotenoids and the growth rate of the yeast. The taxonomical identification of the yeast strain was accomplished through analysis of 5.8S and 26S rRNA by the Centraalbureau voor Schimmelcultures (CBS) and biochemical and molecular approaches. The yeast was identified as Rhodotorula mucilaginosa. In order to analyze the influence of factors on production of carotenoids and growth rate we used a methodology of response surface (RSM), and a central composite factorial design (CCD) with three factors and six replicates of central point was applied. The 20 experiments were done in batch in 91h and samples were collected at different physiological stages of the culture, at maximum growth rate (log phase), at deceleration growth phase (2h initial at the entrance of the stationary phase) and at stationary phase (60h after reaching the maximum cell mass). It implicates that carotenogenesis is not associated with cellular growth. The maximum carotenoid yield per cell mass (&#956;g/g) occurred at deceleration growth phase. The growth rate (&#956;) and total carotenoid yield (&#956;g/g) calculations well- adjusted to the mathematical model, with R2 of 0.96 and 0.91, respectively, and the lack of fit was not significant (p>0.05). The levels of light (&#956;mol m-2s-1), arabinose (%w/v) and temperature (°C) that created a maximum answer of total carotenoid yield (93.92 &#956;g/g) were 100 &#956;mol m-2s-1; 5% and 18 °C and growth rate (0.31h-1) were 63.6 &#956;mol m-2s-1; 3.7% and 24.6 °C. / Em micro-organismos produtores, carotenoides são pigmentos, precursores de vitamina A, que os protegem contra o estresse oxidativo. Fatores ambientais extrínsecos tais como temperatura, fontes específicas de carbono e indutores de espécies reativas de oxigênio (ROS) como luz e peróxido de hidrogênio associados a condições fisiológicas (fase de crescimento exponencial máxima, fase estacionária inicial e tardia) influenciam no acúmulo de carotenoides pelas células microbianas. Uma levedura pigmentada foi isolada do horto da Universidade Federal de Viçosa, Minas Gerais, Brasil. Os objetivos desse trabalho foram identificar esta levedura isolada no horto da UFV e analisar a influência dos fatores ambientais (temperatura, intensidade de luz e concentração de arabinose) e das diferentes condições fisiológicas (fase log, estacionária inicial e tardia) na produção de carotenoides e na velocidade de crescimento da levedura. A identificação taxonômica da levedura foi feita pelo Centraalbureau voor Schimmelcultures (CBS) por meio das análises das sequências 5,8S e 26S do rRNA e por ferramentas moleculares e bioquímicas, resultando na identificação da espécie como Rhodotorula mucilaginosa. A influência das condições ambientais e fisiológicas na produção de carotenoides e na taxa de crescimento foi verificada pela metodologia de superfície de resposta (RSM) por meio de um delineamento composto central (CCD) com três fatores e seis replicatas do ponto central. Os 20 experimentos foram feitos em 91h de batelada e as amostras foram coletadas em diferentes estados fisiológicos da cultura, isto é na fase de crescimento máximo (fase log), fase de desaceleração do crescimento (2h iniciais na entrada da fase estacionária) e fase estacionária (60h após alcançar a massa celular máxima). Demonstrou-se que a formação de carotenoides pela levedura não é associada ao crescimento. O rendimento máximo de carotenoides por massa celular (&#956;g/g) ocorreu na fase de desaceleração do crescimento. A velocidade específica máxima de crescimento (&#956;max) e o rendimento em carotenóide total por massa celular (&#956;g/g) foram ajustados ao modelo matemático, com R2 de 0,96 e 0,91 respectivamente, e o desajuste não foi significante (p>0,05). Os níveis de intensidade de luz (&#956;mol m-2s-1), arabinose (%p/v) e temperatura (°C) que criaram a resposta máxima de rendimento de carotenóides totais (93,92 &#956;g/g) foram 100 &#956;mol m-2s-1; 5%; 18 °C e da velocidade de crescimento (0,31h-1) foram 63,6 &#956;mol m-2s-1; 3,7% e 24,6 °C.