Spelling suggestions: "subject:"factorial design"" "subject:"factorial 1design""
101 |
Optimization of Recombinant Protein Production by a Fungal HostGheshlaghi, Reza January 2007 (has links)
The natural ability of filamentous fungi to synthesize, glycosylate, and secrete high levels of protein products has made them potentially attractive hosts for heterologous protein production. Advances in fungal genetics enabled the expression of several high value proteins in filamentous fungi. Particularly the genus, Aspergillus has proven to be potentially useful for the expression of eukaryotic gene products. This thesis pertains to the optimization of recombinant protein production by the fungal host, Aspergillus niger. The target recombinant protein of interest is hen egg white lysozyme (HEWL). This protein encoded in the genome resulting in relatively stable gene construct; however, it is subject to extracellular protease attack.
The objective of the proposed research is the development and application of engineering methodology for the analysis and optimization of a fungal bioprocess for recombinant protein production. The underlying hypothesis is that a significant improvement of target protein productivity is achievable by using appropriate optimization techniques.
To accomplish this, during the first phase of this study a statistically based experimental method was used to systematically elucidate the effect of medium components (starch, peptone, ammonium sulfate, yeast extract, and CaCl₂.2H₂O) on hen egg white lysozyme production by Aspergillus niger HEWL WT-13-16. A 2⁵⁻¹ fractional factorial design augmented with center points revealed that peptone, starch, and ammonium sulfate were the most significant factors, whereas the other medium components were not important within the levels tested. Then, the method of steepest ascent was employed to approach the proximity of optimum. This task was followed by a central composite design to develop a response surface for medium optimization. The optimum medium composition for lysozyme production was found to be: starch 34 g/L, peptone 34 g/L, ammonium sulfate 11.9 g/L, yeast extract 0.5 g/L, and CaCl₂.2H₂O 0.5 g/L. This medium was projected to produce theoretically 212 mg/L lysozyme. Using this optimized medium, an experimentally observed maximum lysozyme concentration of 209±18 mg/L verified the applied methodology.
A second optimization approach was based on metabolic flux analysis (MFA). A comprehensive metabolic network comprising three intracellular compartments (cytoplasm, mitochondrion and peroxisome) was developed for Aspergillus niger. The metabolic flux network included carbohydrate and amino acid metabolism in both anabolic and catabolic reactions. According to experimental observations, the time course of fermentation was divided into five phases, each with unique physiological properties. The network was used to form a set of linear algebraic equations based on the stoichiometry of the reactions by assuming pseudo-steady state for intracellular metabolites. The metabolic flux model consists of 137 metabolites and 287 processes, of which 181 represent biochemical conversions and 106 represent transport processes between the different compartments and the extracellular environment. In addition, due to the physiological evidence some biochemical reactions considered to be active only in one direction. Linear programming was used for optimizing of the specific growth rate as the objective function in combination with 37 measured input and output fluxes of the key metabolites to evaluate corresponding intracellular flux distributions throughout the batch fermentations. The general applicability of the methodology was evaluated by establishing commonality to optimize recombinant HEWL production. The proposed model was able to predict correctly the specific growth rate, oxygen uptake rate, and carbon dioxide evolution rate with good precision.
The results of the metabolic flux and sensitivity analysis were employed for medium design. Growth was biphasic; glucose was utilized initially as the carbon source and was followed by its oxidation product, gluconate, later. Logarithmic sensitivity analysis revealed that the addition of proline, alanine and glutamate benefited growth in defined media. The experimental observations and flux analysis showed that tyrosine was a potential candidate for biomass production improvement. The two amino acids, namely proline and tyrosine benefited biomass production during the initial growth phases. Glutamate and alanine were particularly important during the latter stages of the batch process.
A series of growth studies were conducted with the identified amino acids added in the medium. In these preliminary nutritional experiments the contribution to growth enhancement was 46% for proline, 23% for glutamate, and 22% for tyrosine. Model predictions were further verified by conducting batch and fed-batch fermentations in a 7- liter bioreactor. The programmed addition of four amino acids (proline, glutamate, alanine, and tyrosine) according to a predetermined schedule resulted in a 44% improvement in biomass and 41% improvement in recombinant protein production. The experiments also confirmed the model prediction that extra amount of amino acids besides the identified ones would not significantly enhance biomass and the recombinant protein production.
A computer-based control system was developed for the on-line monitoring and control of the major state variables (e.g., temperature, pH, and DO) during the time course of fermentation. The graphical programming environment, LabVIEW was used to acquire and integrate these variables in a supervisor computer. The temperature of the bioreactor during sterilization and fermentation was controlled using a cascade methodology. The controller parameters of the master and slave loops were determined experimentally to yield a smooth response with minimum overshoot of both the bioreactor and jacket temperatures. The program scheduled various required steps in an established order during the fermentation. This feature of the software guarantees that every necessary operation will be met. The graphical representation of the process is displayed on the screen and helps the user to follow the process and perform the required adjustments. Furthermore, different variables can be observed simultaneously and saved in text or spreadsheet files for further analysis.
|
102 |
Optimization of Recombinant Protein Production by a Fungal HostGheshlaghi, Reza January 2007 (has links)
The natural ability of filamentous fungi to synthesize, glycosylate, and secrete high levels of protein products has made them potentially attractive hosts for heterologous protein production. Advances in fungal genetics enabled the expression of several high value proteins in filamentous fungi. Particularly the genus, Aspergillus has proven to be potentially useful for the expression of eukaryotic gene products. This thesis pertains to the optimization of recombinant protein production by the fungal host, Aspergillus niger. The target recombinant protein of interest is hen egg white lysozyme (HEWL). This protein encoded in the genome resulting in relatively stable gene construct; however, it is subject to extracellular protease attack.
The objective of the proposed research is the development and application of engineering methodology for the analysis and optimization of a fungal bioprocess for recombinant protein production. The underlying hypothesis is that a significant improvement of target protein productivity is achievable by using appropriate optimization techniques.
To accomplish this, during the first phase of this study a statistically based experimental method was used to systematically elucidate the effect of medium components (starch, peptone, ammonium sulfate, yeast extract, and CaCl₂.2H₂O) on hen egg white lysozyme production by Aspergillus niger HEWL WT-13-16. A 2⁵⁻¹ fractional factorial design augmented with center points revealed that peptone, starch, and ammonium sulfate were the most significant factors, whereas the other medium components were not important within the levels tested. Then, the method of steepest ascent was employed to approach the proximity of optimum. This task was followed by a central composite design to develop a response surface for medium optimization. The optimum medium composition for lysozyme production was found to be: starch 34 g/L, peptone 34 g/L, ammonium sulfate 11.9 g/L, yeast extract 0.5 g/L, and CaCl₂.2H₂O 0.5 g/L. This medium was projected to produce theoretically 212 mg/L lysozyme. Using this optimized medium, an experimentally observed maximum lysozyme concentration of 209±18 mg/L verified the applied methodology.
A second optimization approach was based on metabolic flux analysis (MFA). A comprehensive metabolic network comprising three intracellular compartments (cytoplasm, mitochondrion and peroxisome) was developed for Aspergillus niger. The metabolic flux network included carbohydrate and amino acid metabolism in both anabolic and catabolic reactions. According to experimental observations, the time course of fermentation was divided into five phases, each with unique physiological properties. The network was used to form a set of linear algebraic equations based on the stoichiometry of the reactions by assuming pseudo-steady state for intracellular metabolites. The metabolic flux model consists of 137 metabolites and 287 processes, of which 181 represent biochemical conversions and 106 represent transport processes between the different compartments and the extracellular environment. In addition, due to the physiological evidence some biochemical reactions considered to be active only in one direction. Linear programming was used for optimizing of the specific growth rate as the objective function in combination with 37 measured input and output fluxes of the key metabolites to evaluate corresponding intracellular flux distributions throughout the batch fermentations. The general applicability of the methodology was evaluated by establishing commonality to optimize recombinant HEWL production. The proposed model was able to predict correctly the specific growth rate, oxygen uptake rate, and carbon dioxide evolution rate with good precision.
The results of the metabolic flux and sensitivity analysis were employed for medium design. Growth was biphasic; glucose was utilized initially as the carbon source and was followed by its oxidation product, gluconate, later. Logarithmic sensitivity analysis revealed that the addition of proline, alanine and glutamate benefited growth in defined media. The experimental observations and flux analysis showed that tyrosine was a potential candidate for biomass production improvement. The two amino acids, namely proline and tyrosine benefited biomass production during the initial growth phases. Glutamate and alanine were particularly important during the latter stages of the batch process.
A series of growth studies were conducted with the identified amino acids added in the medium. In these preliminary nutritional experiments the contribution to growth enhancement was 46% for proline, 23% for glutamate, and 22% for tyrosine. Model predictions were further verified by conducting batch and fed-batch fermentations in a 7- liter bioreactor. The programmed addition of four amino acids (proline, glutamate, alanine, and tyrosine) according to a predetermined schedule resulted in a 44% improvement in biomass and 41% improvement in recombinant protein production. The experiments also confirmed the model prediction that extra amount of amino acids besides the identified ones would not significantly enhance biomass and the recombinant protein production.
A computer-based control system was developed for the on-line monitoring and control of the major state variables (e.g., temperature, pH, and DO) during the time course of fermentation. The graphical programming environment, LabVIEW was used to acquire and integrate these variables in a supervisor computer. The temperature of the bioreactor during sterilization and fermentation was controlled using a cascade methodology. The controller parameters of the master and slave loops were determined experimentally to yield a smooth response with minimum overshoot of both the bioreactor and jacket temperatures. The program scheduled various required steps in an established order during the fermentation. This feature of the software guarantees that every necessary operation will be met. The graphical representation of the process is displayed on the screen and helps the user to follow the process and perform the required adjustments. Furthermore, different variables can be observed simultaneously and saved in text or spreadsheet files for further analysis.
|
103 |
Some new ideas on fractional factorial design and computer experimentSu, Heng 08 June 2015 (has links)
This thesis consists of two parts. The first part is on fractional factorial design, and the second part is on computer experiment. The first part has two chapters. In the first chapter, we use the concept of conditional main effect, and propose the CME analysis to solve the problem of effect aliasing in two-level fractional factorial design. In the second chapter, we study the conversion rates of a system of webpages with the proposed funnel testing method, by using directed graph to represent the system, fractional factorial design to conduct the experiment, and a method to optimize the total conversion rate with respect to all the webpages in the system. The second part also has two chapters. In the third chapter, we use regression models to quantify the model form uncertainties in the Perez model in building energy simulations. In the last chapter, we propose a new Gaussian process that can jointly model both point and integral responses.
|
104 |
A multivariate approach to QSARHellberg, Sven January 1986 (has links)
Quantitative structure-activity relationships (OSAR) constitute empirical analogy models connecting chemical structure and biological activity. The analogy approach to QSAR assume that the factors important in the biological system also are contained in chemical model systems. The development of a QSAR can be divided into subproblems: 1. to quantify chemical structure in terms of latent variables expressing analogy, 2. to design test series of compounds, 3. to measure biological activity and 4. to construct a mathematical model connecting chemical structure and biological activity. In this thesis it is proposed that many possibly relevant descriptors should be considered simultaneously in order to efficiently capture the unknown factors inherent in the descriptors. The importance of multivariately and multipositionally varied test series is discussed. Multivariate projection methods such as PCA and PLS are shown to be appropriate far QSAR and to closely correspond to the analogy assumption. The multivariate analogy approach is applied to a beta- adrenergic agents, b haloalkanes, c halogenated ethyl methyl ethers and d four different families of peptides. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1986, härtill 8 uppsatser</p> / digitalisering@umu
|
105 |
Aplicação de polieletrólitos para a separação de metais em efluentes da suinocultura / Polyelectrolytes aplication of metal separation in wastewater of swine poultrySteinmetz, Ricardo Luis Radis 09 February 2007 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / The increase on swine livestock activity demands profitable resources and environmentally sustainable for the treatment, disposal and the residual water reuse. Due to the high wastewater volume, they have a huge pollutant load, among them several metals, that can cause environment impact. This work presents an evaluation of phase separation for Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Sr and Zn removal in swine manure through the coagulation and flocculation whit synthetic and natural polyelectrolyte. For this proposal, the metals were monitored in the effluent and solid-liquid separation assays (Jar Test) with poliphenolic polymer (Tannin) and polyacrilamide (PAM) applied at different concentration. The optimization was accomplished by the application of factorial design. For the metal determination three mixtures of reagents had been evaluated (nitric acid + perchloric acid, sulfuric acid + hydrogen peroxide and nitric acid + hydrogen peroxide) for samples decomposition of swine manure, the best result for recovery and correlation was found to nitric acid and hydrogen peroxide mixture. After the separation of the liquid fraction, reductions between 68 and 99% were found out in the investigated metal concentrations. Besides that, reductions over 90% for chemical oxygen demand were also observed. A significant influence in turbidity removal only by the tannin utilization was found out. However the PAM application improved directly the flocks generation and influenced the sludge volume reduction. The polyelectrolyte use provided the reduction of metal concentration in the wastewater to adjust to the brazilian legislation for discharging into water bodies or for reuse in irrigation systems. The sludge produced after the solid-liquid separation also showed concentrations of inorganic constituents below of maximum limits claimed by legislation for the agricultural use. / O crescimento da atividade suinícola demanda recursos rentáveis e ambientalmente sustentáveis para o tratamento, disposição e reuso de suas águas residuárias. Além de seu grande volume de efluentes, estes possuem alta carga de poluentes, entre eles diversos metais, danosos ao meio ambiente. Este trabalho apresenta uma avaliação da separação de fases para remoção de Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Sr e Zn em dejetos de suínos através de coagulação e floculação com polieletrólitos, sintético e natural. Para isso, monitoraram-se os metais no efluente e foram realizados ensaios de separação sólido-líquido (Teste de Jarro) com aplicação de polímero polifenólico natural (tanino) e poliacrilamida (PAM). As otimizações foram realizadas aplicando planejamento fatorial. Para as determinações de metais foram avaliadas decomposições de amostras de dejeto de suíno empregando três misturas de reagentes (ácido nítrico + ácido perclórico, ácido sulfúrico + peróxido de hidrogênio, ácido nítrico + peróxido de hidrogênio), onde os resultados de recuperação e correlação permitiram a escolha da mistura ácido nítrico e peróxido de hidrogênio. Foram observadas reduções entre 68% e 99% nas concentrações dos metais investigados após separação da fração líquida, além de reduções superiores 90% para a demanda química de oxigênio e superiores a 98% para a turbidez. Foi constatada interação na remoção de turbidez somente ao emprego de Tanino, porém a aplicação de PAM melhorou diretamente a formação dos flocos e sedimentação do lodo. Os polieletrólitos proporcionaram a redução da concentração de metais na água residuária, auxiliando no enquadramento das concentrações dos metais investigados à legislação, para descarte em corpos de água receptores ou ao reuso em sistemas de irrigação. O lodo produzido após a separação sólido-líquido apresentou concentrações de constituintes inorgânicos abaixo dos limites máximos exigidos pela legislação para o uso agrícola.
|
106 |
Propriedades nutricionais e funcionais de palma (Opuntia ficus-indica) e sua utilização no processamento de geleiasSantos, Marília Cícera Gomes dos 26 February 2014 (has links)
Made available in DSpace on 2015-04-17T14:49:37Z (GMT). No. of bitstreams: 1
arquivototal.pdf: 1143861 bytes, checksum: 8029067c3256f4f85c447cd92bab4fe1 (MD5)
Previous issue date: 2014-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Natural from Mexico, the family of cactus corresponds to approximately 130 genera and 1500 species, lying mainly distributed in arid and semi-arid regions of the New World. One way to include this vegetable in human nutrition is process it into jelly. The objective of this research was to develop jelly palm (Opuntia ficus-indica) that meets the parameters physical, chemical, microbiological and sensory of quality, and characterize it in terms of nutritional composition and antioxidant potential. Formulations for the jelly palm were developed using 23 factorial design with 3 central points totaling 11 trials; having as independent variables the concentrations of sucrose in relation to pulp concentration (S/P), citric acid concentration (A) and concentration of pectin (P). The dependent variables were: pH, water activity, instrumental color (brightness, chromaticity a * and b *), texture, soluble solids and titratable acidity. Considering the parameters of physical quality and chemical, formulations of jelly palm were selected and conducted for microbiological analysis, which allowed the realization of sensory analysis without causing health risk assessors. The sensory characteristics were obtained by means of acceptance test and purchase s intent test. The formulation that received the best acceptance rates and lower sugar content was sent to continue the study in order to evaluate their nutritional and functional properties. The results of the experimental design demonstrated that pH, texture, soluble solids and titratable acidity were the dependent variables with the biggest influence on the quality of jelly palm due to models showed significance with 95 % confidence. The formulation with 35 % sucrose, 65 % pulp, 0.55 % citric acid and 0.5 % pectin was selected to continue the study due to lower sugar content and higher amount of pulp. The nutritional composition showed that the jelly palm is a compatible product to marmalades, has significant quantities of bioactive compounds and is low calorie. However it has an expressive little capacity to sequester the DPPH and ABTS radical. These data make the palm a product with technological feasibility. / Natural do México a família das cactáceas corresponde a aproximadamente 130 gêneros e 1500 espécies, encontrando-se distribuída principalmente nas regiões áridas e semiáridas do novo mundo. Uma das formas de incluir esse vegetal na alimentação humana é processá-lo em geleia. O objetivo desta pesquisa foi desenvolver geleia de palma (Opuntia ficus-indica) que atenda aos parâmetros de qualidade física, química, microbiológica e sensorial, além de caracterizá-la quanto à composição nutricional e seu potencial antioxidante. As formulações para a geleia de palma foram desenvolvidas utilizando o planejamento fatorial 23, com 3 pontos centrais totalizando 11 ensaios; tendo como variáveis independentes as concentrações de sacarose em relação à concentração de polpa (S/P), concentração de ácido cítrico (A) e concentração de pectina (P). As variáveis dependentes analisadas foram: pH, atividade de água, cor instrumental (luminosidade, cromaticidade a* e b*), textura, sólidos solúveis e acidez titulável. Considerando os parâmetros de qualidade físicos e químicos as formulações de geleia de palma foram selecionadas e conduzidas para análise microbiológica, que permitiu a realização da análise sensorial sem causar risco à saúde dos provadores. As características sensoriais foram obtidas por meio dos testes de aceitação e de intenção de compra. A formulação que recebeu os melhores índices de aceitação e o menor teor de açúcar foi encaminhada para dar continuidade ao estudo, de modo a avaliar suas propriedades nutricionais e funcionais. Os resultados do planejamento experimental demonstraram que as variáveis dependente de maior influência na qualidade das geleias de palma foram pH, textura, sólidos solúveis e acidez titulável, pois apresentaram modelos com significância de 95% de confiança. A formulação com 35% de sacarose, 65% de polpa, 0,55% de ácido cítrico e 0,5% de pectina foi selecionada para dar continuidade ao estudo por apresentar menor teor de açúcar e maior quantidade de polpa. A composição nutricional demonstrou que a geleia de palma é um produto compatível as geleias de fruta, possui quantidade apreciável de compostos bioativos e é hipocalórica. No entanto possui uma capacidade pouco expressiva para sequestrar o radical DPPH e ABTS. Esses dados tornam a palma um produto com viabilidade tecnológica.
|
107 |
Secagem em camada de espuma da polpa de cajá. / Foam mat drying of the cajá pulp.FERNANDES, Tâmila Kassimura da Silva. 13 June 2018 (has links)
Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-06-13T13:18:30Z
No. of bitstreams: 1
TÂMILA KASSIMURA DA SILVA FERNANDES - DISSERTAÇÃO PPGEA 2010..pdf: 33235363 bytes, checksum: 4b55d8a3a81c743809e6243d3ff527ae (MD5) / Made available in DSpace on 2018-06-13T13:18:30Z (GMT). No. of bitstreams: 1
TÂMILA KASSIMURA DA SILVA FERNANDES - DISSERTAÇÃO PPGEA 2010..pdf: 33235363 bytes, checksum: 4b55d8a3a81c743809e6243d3ff527ae (MD5)
Previous issue date: 2010-12 / Este trabalho foi desenvolvido com o objetivo de desidratar a polpa de cajá através
do processo de secagem em camada de espuma e analisar, através do planejamento
experimental fatorial, o produto em pó obtido. Três formulações foram elaboradas com a
polpa de cajá integral e três diferentes concentrações do emulsificante Emustab® (1, 2 e
3%), e uma concentração fixa do aditivo Super Liga Neutra (2%), as quais foram agitadas
em batedeira durante 15 minutos, formando espuma. A polpa de cajá e as formulações
foram caracterizadas quanto aos parâmetros químicos, físicos e físico-químicos. As
Formulações (espumas) 1, 2 e 3 foram desidratadas em estufa com circulação forçada de
ar, nas temperaturas de 60, 70 e 80 °C e com espessura da camada de espuma de 0,5; 1,0 e 1,5 cm. Os modelos de Page, Henderson & Pabis e Cavalcanti Mata foram ajustados aos dados experimentais das curvas de secagem. Os pós obtidos ao fim do processo de secagem foram analisados quanto aos parâmetros teor de água, °Brix, pH, acidez, açúcares (redutores, totais e não-redutores), ácido ascórbico, cinzas, cor, atividade de água e rendimento, com a finalidade de se avaliar a influência da temperatura de secagem, espessura da camada de espuma e da concentração de Emustab, através do planejamento experimental fatorial. Determinou-se a isoterma de adsorção de água a 25 °C, da melhor amostra em pó selecionada através do planejamento fatorial, e a ela se ajustaram os modelos de GAB, Oswin e Peleg. Com os resultados obtidos neste trabalho verificou-se que a polpa de cajá integral é ácida e pode ser considerada fonte de vitamina C; trata-se de um fluido pseudoplástico, em que o modelo de Herschel Bulkley foi o que melhor se ajustou aos dados experimentais. Avaliando-se os parâmetros de massa específica, expansão volumétrica e estabilidade da espuma, as três formulações estudadas (1, 2 e 3) se apresentaram dentro dos padrões de secagem em camada de espuma; verificou-se a influência dos aditivos nas características da polpa integral e as espumas apresentaram comportamento pseudoplástico, em que o modelo de Mizrahi-Berk foi o que melhor se ajustou aos dados experimentais. As curvas de secagem das espumas foram influenciadas pela espessura da camada e pela temperatura de secagem. As secagens mais rápidas ocorreram na menor espessura e maior temperatura e apresentaram menor teor de água final; a secagem mais rápida ocorreu na Formulação 3, com maior concentração de Emustab. O modelo de Cavalcanti Mata foi o que melhor se ajustou às curvas de cinética de secagem das espumas. Através do planejamento experimental verificou-se que o melhor pó encontrado foi o do Experimento 2 (polpa de cajá com 3% de Emustab e 2% de Super Liga Neutra; espessura da camada de espuma de 0,5 cm e temperatura de secagem de 60 °C). / The cajá pulp was dryed using foam-mat drying process and results were analyzed
using the experimental factorial design. Were prepared formulations of cajá pulp with
three different concentrations of the emulsifier Emustab® (1, 2 and 3%) and fixed
concentration Super Liga Neutra (2%) additive; this mixture was stirred during 15 minutes
until the foam formation. AH samples at the end were analyzed for its chemical, physical
and physico-chemical properties. The Formulations 1, 2 and 3% were dried in a stove with
air circulation at 60, 70 and 80 °C and thickness 0.5; 1.0 and 1.5 cm. The Page, Henderson & Pabis and Cavalcanti Mata models were used to fit the experimental data. The moisture content, °Brix, pH, acidity, sugars (reducing, total and non-reducing sugars), ascorbic acid, ashes, color, water activity and yield of the powder pulp was determined to study the effect of the drying temperature, foam layer thickness and the emulsifier concentration. From these results, the best sample was selected to study the moisture adsorption isotherm at 25 °C, fitting data by the GAB, Oswin and Peleg models. According the results it can be concluded that the whole cajá pulp is acid and could have its applications as a vitamin C source; furthermore is classified as pseudoplastic fluid, whereby its experimental data was best fítted by the Herschel Bulkley model. It can be stated that the density, volumetric expansion and stability of the foam of the three different formulations were in agreement with the drying standards of foam layers. There was an effect of the additives on the properties of the whole pulp as well as on the different formulations, whereby the formulations presented a pseudoplastic behavior, with its experimental data best fitted by the Mizrahi-Berk model. The drying curves were affected by the thickness of the layer and temperature. It was noticed that thinner layers resulted in higher drying rates with a lower final moisture content. The highest drying rate was obtained by the sample with 3% of the emulsifier. The experimental data of the drying process was best fitted by the Cavalcanti Mata model. According to the experimental factorial design the sample with the concentration of 3% of Emustab® and 2% of Super Liga Neutra, dried with a layer thickness of 0.5 cm at a temperature of 60 °C presented the best results.
|
108 |
Finite Element Modelling and Parametric Studies of Semi-Closed Thin-Walled Steel Polygonal Columns - Application on Steel Lattice Towers for Wind TurbinesRyan, Bona January 2017 (has links)
The trend of structural engineering in the recent years is toward the use of lighter and moreeconomical structural elements. In steel construction, peculiarly, thin-walled structural elements arebecoming more popular and have a growing importance. Improved techniques in a manufacturing ofthin-walled elements have led to increased competitiveness of such products in the buildingapplications. Some examples of such structural element can be found in everyday life in form ofcolumns, studs, roofing trusses, and light-weight frames. However, the use of slender profiles and acomplex cross sections shape lead to requirements to study instability phenomenon in a form of local,distortional, flexural, torsional and coupled instability. Such complex structural behavior is inevitablyaccompanied by demand to improve calculation methods and design provisions. In this thesis, aninnovative solution of structural element composed of thin-walled plates is proposed for theapplication on lattice support structure of wind turbine.Thin-walled cold-formed profiles are steel products usually made from cold rolled coils and folded inthe second step. In this way, only open profiles can be produced. The predominant problem of theopen cross-section is the excessive torsional effect caused by the non-coincidence between the shearcenter and mass center, and a poor torsional resistance. A better response is possible with closed crosssections, but such profiles could not be produced by the folding. The solution is to make semi-closedsection by assembling them into polygonal profiles with mechanical fasteners, as presented in thisthesis.Objective of this work is to study the proposed structural sections in design situation and toinvestigate possible design models. The expected structural behavior of the column is a mixturebetween the open and closed cross-section. These cases will be investigated through numerical study.In this thesis presented a comprehensive parametric study on the ultimate strength of proposed coldformedsteel columns using the Finite Element package ABAQUS. FE models were first developedfor columns by using automation that was made through MATLAB and Python script. The bucklingand non-linear FE study was done for the investigation of local (L), distortional (D) and global (G)possible buckling failures and ultimate resistance, respectively. Modelling issues such as boundaryconditions, meshing, initial imperfections, material models, and non-linear solution controls in FEAwere also addressed.The parametric study involved series of profiles of built-up polygonal cross-section types with variedthickness (t), number of corners (n), diameter (d), slenderness (slend), yield strength (fy), number ofpoints along corner radii (np), extension lip length (lext), gusset plate thickness (tg), member length (l),and density of fasteners (s/d ratio), loaded in compression and bending moment. The bending momentoccurs as the effect of forces acting on the connection. The purpose of this analysis is to study thecritical load, cross-sectional behavior, influence of the amplitude of initial imperfections on theultimate load, and influence of each parameter used in the analysis through Full Factorial Design.
|
109 |
Otimização da co-pirólise de gasóleo pesado com embalagens de PEAD pós-uso utilizando planejamento fatorial / Optimization co-pyrolysys from HDPE and heavy gas oil using factorial design methodologyNey Joppert Junior 07 January 2015 (has links)
A co-pirólise é uma rota promissora, uma vez que minimiza o impacto ambiental causado pela disposição do plástico de maneira inadequada, evita seu acúmulo em lixões e permite um melhor aproveitamento de um recurso natural não-renovável, o petróleo, matéria prima importante para a geração de energia e obtenção de produtos químicos. O presente trabalho teve como objetivo a definição das condições experimentais mais propícias à obtenção de líquidos pirolíticos com alta fração de óleo diesel, resultantes da co-pirólise de polietileno de alta densidade (PEAD) pós-consumo com gasóleo pesado tilizando-se catalisador de FCC (Fluid Catalytic Cracking). Como instrumento de otimização das condições experimentais, optou-se pela Metodologia Planejamento Fatorial. Foi também
estudado o efeito das condições experimentais, como: a temperatura de reação, a relação gasóleo/polietileno e a quantidade de catalisador no meio reacional. As amostras de
polietileno, gasóleo e catalisador foram submetidas à co-pirólise em sistema de leito fixo, sob fluxo constante de nitrogênio, variando-se a temperatura entre 450 C a 550 C, a quantidade de PEAD no meio reacional foi de 0,2 a 0,6 g, e a quantidade de catalisador foi de zero a 0,06 g, mantendo-se fixa a quantidade de gasóleo em 2 g. Foram efetuadas as caracterizações física e química do gasóleo, polietileno pós-uso e do catalisador. Como resultado, obteve-se a produção de 87% de fração de óleo diesel em duas condições diferentes: (a) 550 0C de temperatura sem catalisador; (b) 500 0C de temperatura e 25% de catalisador FCC. Em ambos
os casos, a quantidade de gasóleo pesado e PEAD foram constantes (2 g Gasóleo; 0,2 g PEAD), assim com o tempo de reação de 15 minutos. A fração de óleo diesel obtida neste
estudo alcançou o poder calorífico de 44,0 MJ/Kg que é similar ao óleo diesel comercial. É importante ressaltar que em ambos os casos nenhum resíduo foi produzido, sendo uma rota
ambientalmente importante para reciclagem de embalagens plásticas contaminadas com óleo lubrificante originárias de postos de serviço, visando à recuperação de ambos conteúdo
energético e orgânico dos resíduos de embalagens plásticas pós-uso / In this work it was studied the co-pyrolysis process applied to HDPE plastic package with motor oil residues with Heavy Gas Oil and FCC Catalyst. The main objective of this work was to find the experimental conditions that enhanced the diesel fuel fraction in the pyrolitic oil. Factorial Design Methodology (FDM) was developed to enhance diesel fuel fraction (C9-C23) from waste high-density polyethylene (HDPE) and heavy gas oil (HGO) through copyrolysis. FDM was used for optimization of the following reaction parameters: temperature, catalyst and HDPE amounts. The HGO amount was constant (2.0 g) in all experiments. The model optimum conditions were determined to be temperature of 550 C, HDPE = 0.20 g and no FCC catalyst. Under such conditions, 94% of pyrolytic oil was recovered, of which diesel fuel fraction was 93% (87% diesel fuel fraction yield), no residue was produced and 6% of
noncondensable gaseous/volatile fraction was obtained. Seeking to reduce the cost due to high process temperatures, the impact of using higher catalyst content (25 %) with a lower temperature (500 C) was investigated. Under these conditions, 88% of pyrolytic oil was recovered (diesel fuel fraction yield was also 87%) as well as 12% of the noncondensable gaseous/volatile fraction. No waste was produced in these conditions, being an environmentally friendly approach for recycling the waste plastic. The diesel fuel fraction obtained in this study achieved heating value (44.0 MJ/Kg) similar to commercial diesel oil. This paper demonstrated the usefulness of using FDM to predict and to optimize diesel fuel fraction yield with a great reduction in the number of experiments. Based on experimental results, co-pyrolysis can represent a significant role in future in the recovery of both energetic and organic content of HDPE plastic package with motor oil residues
|
110 |
DESONIDA: VALIDAÇÃO DE MÉTODOS ANALÍTICOS E ESTUDO DE FOTOESTABILIDADE DE FORMULAÇÕES / DESONIDE: VALIDATION OF ANALYTICAL METHOD AND PHOTOSTABILITY STUDY OF FORMULATIONSBraga, Muriele Picoli 26 April 2013 (has links)
Desonide is a nonfluorinated corticosteroid with glucorticoid activity. It is used
topically in the treatment of atopic dermatitis, inflammation, pruritus and seborrheic
dermatitis of mild to moderate severity. In Brazil, this drug is available as ointment,
cream, lotion, hair lotion and cream gel. Until now, there are no official methods
focused in the quality control of desonide raw material or its pharmaceutical forms. In
this work, methods were developed and validated by high performance liquid
chromatography (HPLC) for quantitation of desonide in lotion and cream gel.
Furthermore, photostability studies of these formulations were conducted. The HPLC
methods were validated by parameters of linearity, precision, accuracy, robustness
and specificity, which results showed that both methods are stability-indicating.
Chemometric tools were used to study the robustness of the proposed methods
(desonide lotion and cream gel) and also for the optimization of chromatographic
conditions (cream gel). Photostability studies were conducted with an equivalent
procedure, by exposure to UVA radiation (352 nm) portions of the samples for a
period of 48 h. The results showed that both formulations undergo photodegradation,
and the lotion exhibits a degradation rate greater than the cream gel (t90% 1.58 h for
the lotion and 3.65 h for the gel). The study of the kinetics of the reactions indicated
that lotion follows second-order kinetics, while the cream gel follows first order
kinetics. / A desonida é um corticosteroide não fluorado com atividade glicocorticoide
usada topicamente no tratamento de dermatite atópica, doenças inflamatórias e
pruriginosas e dermatite seborreica de intensidade leve a moderada. No mercado
brasileiro estão disponíveis as formas farmacêuticas pomada, creme, loção cremosa,
gel creme e loção capilar. Até o momento, não constam monografias da desonida
em compêndios oficiais, tanto para o controle de qualidade da matéria-prima, quanto
das formas farmacêuticas. No presente trabalho, foram desenvolvidos e validados
métodos por cromatografia líquida de alta eficiência (CLAE) para quantificação da
desonida em loção cremosa e gel creme, e foram realizados estudos de
fotoestabilidade dessas formulações. Os métodos por CLAE para ambas as
formulações foram validados frente aos parâmetros de linearidade, precisão,
exatidão, robustez e especificidade, cujos resultados indicaram que ambos os
métodos são indicativos de estabilidade. Ferramentas quimiométricas foram usadas
para o estudo da robustez dos métodos propostos (loção e gel creme), bem como na
etapa de otimização das condições cromatográficas (gel creme). Os estudos de
fotoestabilidade para ambas as amostras foram conduzidos de maneira equivalente,
através de exposição à radiação UVA (352 nm) de porções da amostra, por até 48h,
e demonstraram que as duas formulações analisadas sofrem fotodegradação, sendo
que a velocidade de degradação da loção é maior do que a observada para o gel
creme (t90% de 1,58 h para a loção e de 3,65 h para o gel). O estudo da cinética das
reações indicou que a loção cremosa segue cinética de segunda ordem, enquanto o
gel creme segue cinética de primeira ordem.
|
Page generated in 0.0433 seconds