Método de Taguchi aplicado a um processo de corte por fusão de um tecido sintético

A company must have full knowledge and control of its operations so as to meet the market requirements and meet their production goals. Thus this paper uses the Taguchi method to extend the operational control of a cutting process by fusion of a synthetic fabric in the longitudinal direction. For process analysis and tracking of possible causes of the problem techniques of Production Engineering as the cause and effect diagram, also known as Ishikawa diagram, and design of experiments were used, the last one was applied to the design techniques of Taguchi. Finally the preparation method of understanding and design of experiment was due to the use of the software MINITAB v15 ®, which showed that the speed of rolling the fabric after cutting is crucial for controlling the entire operation

A utilização de modelos matemáticos para a otimização de processos

This dissertation has as main theme the discuss about how the use of mathematical models for process optimization. The current scenario of strong competition to conquer the consumer market necessitates the development of improvements to better performance of the process as a whole, is to reduce costs, increase efficiency or effectiveness. Thus, the use of methodologies to assist in this process is becoming increasingly viable. Methodologies developed in the past are being studied and improved. An example is the Desirability, the object of the present study, which was developed in the 80's and has been improved over time. To understand and study this methodology was applied to the desirability function in three instances, where it was used Design of Experiments (DOE), taken from scientific papers, using the Solver tool (Excel ®) and desirability (Minitab ®). Thus, in addition to studying the methodology, it was possible to compare the performance of tools used for optimization in different situations. From the results of this study, it was possible to validate the superiority of one of the models studied compared fairly

Melhoria da qualidade de um processo de usinagem utilizando as técnicas de avaliação de Taguchi

Delivering to the customers a product or service with the expected quality associated to the huge competitiveness that exists in the market nowadays, has been making organizations increasingly focus on quality planning using techniques which are directed towards the continuous improvement process and production optimization. Thus, this paper aims to improve a machining process using the techniques of experimental design to the optimization and this also includes the analysis of the measurement system. For this purpose, the alloy Nimonic 80A, a nickel base superalloy, was used in the process due to its widespread use for high temperatures, applying this study the robust method proposed by Genichi Taguchi, determining the influence of the factors considered input variables, cutting speed, feed rate, depth of cut, type of tool, lubrication, and material hardness, in the output or response variable, surface roughness, concluding with the use of Taguchi orthogonal array L16 and by analysis of ANOVA that the factor feed rate is significant and offers greater effect on the response variable studied, should be set to 0,12mm/rev. Moreover, the factor type of tool has more influence on the process when compared to other factors, being CP250 the one more suitable to the process. Lastly, the interaction feed rate x cutting speed provides greater significance in the process regarding to surface roughness variable, being the best match between them 0,12mm/rev to the feed rate and 90m/min to the cutting speed. In order to evaluate the measurement system, it was applied the repeatability and reproducibility method (R&R), through which we saw that the system needs improvement (R & R = 88.04% >>> 30%) as the value found in the study was well above compared to the one that classifies the system as inappropriate

Compósitos de nanocelulose / PHBV: manta microfibrilica por eletrofiação

Pós-graduação em Engenharia Mecânica - FEG

Diferentes métodos de aglutinação para melhoria de processos com múltiplas respostas

Pós-graduação em Engenharia Mecânica - FEG

Utilização de lama vermelha para oxidação eletrolítica assistida por plasma de liga de alumínio

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

CORRELAÇÕES ENTRE PERCEPÇÃO DA PASSAGEM DO TEMPO, ATENÇÃO DIFUSA E ANSIEDADE

O presente estudo teve como objetivo avaliar aspectos psicofisiológicos da ansiedade em particular a atenção e a percepção da passagem do tempo. Foi aplicada a escala psicométrica de ansiedade do IDATE em 180 alunos do curso de Educação Física da Universidade de São Paulo em sala de aula. Foram selecionados 15 voluntários mais ansiosos e 15 menos ansiosos foi considerado o IDATE traço por apresentar características mais constantes da ansiedade. O experimento 1 foi a tarefa de Tempo Espontâneo onde os participantes deviam bater o dedo no botão A do joystick da forma mais regular e precisa possível por um minuto. Já no experimento 2 os participantes foram orientados a responder o mais rápido possível ao surgimento do estimulo (ponto branco 0,4 grau) com uma luminância de 80 cd/m contra um fundo cinza pressionando o botão A do joystick com qualquer dedo da mão dominante (TRS). Os estímulos eram apresentados randomicamente por 82 posições diferentes na tela do computador. Após tratamento dos dados e analise estatística, o estudo de caráter geral e exploratório apresentado aqui mostra tendências, mas não correlações significativas entre as medidas. Alguns dados, no entanto, chamam a atenção e devem ser considerados no planejamento de experimentos futuros.

Alquilação de tolueno com propeno, através de complexo ferro (II) ᵦ- diimina homogêneo e heterogeneizado em MCM-41, Al-MCM-41 e SBA-15

This work describes the synthesis and aplication of homogeneous and heterogenized iron catalysts in the alkylation reaction of toluene with propene, empolying experimental design. The homogenous complex was obtained trough the synthesis of the organic ligand folowed by the complexation of the iron(II) chloride. As to the heterogenized complexes, first were synthetized the inorganic supports (SBA-15, MCM-41 and Al-MCM-41). Then, it was synthetized the ligand again, that through funcionalization with chloropropyltrimethoxysilane (CPTMS), was anchored on the support previously calcinated. To these anchored ligands, was complexed the iron(II) chloride, previously solubilizated in tetrahydrofuran (THF). The organic ligand characterization was accomplished trough nuclear magnetic resonance (NMR) and Infrared spectroscopy (IV). The supports were characterized with x-ray diffraction (DRX), texture analysis with nitrogen adsorption/desorption (before and after the anchoring), termogravimetric analysis (TG) and infrared (IV). The metalic content was quantified trough the atomic absorption spectrophotometry (AAS). The complexes were tested in catalytic reactions emolying ethylaluminium sesquichloride (EASC) as co-catalyst in steel reactor, under mecanic stirring. The reaction conditions ranged from 4 to 36 ◦C, with many aluminum/iron ratios. The catalysts were actives in homogeneous and heterogenized ways. The homogenous catalytic complex showed a maximum turnover frequency (TOF) of 8.63 ×103 · h −1 , while, in some conditions, the anchored complexes showed better results, with TOF of until 8.08 ×103 · h −1 . Aditionally, it was possible to determine an equation, to the homogenous catalyst, that describes the product quantity in function of reacional temperature and aluminum/iron ratio.

Otimização de parâmetros mecânicos e microestruturais dos moldes em areia de sílica ligados quimicamente pelo processo de cura a frio em fundição de aço

Surface defects on steel parts borne costs of smelting industries due to the need of rework. Sand molds are frequently used in foundry industries and largely responsible for providing surface defects. This study aims to optimize the levels of the molding process variables to minimize the occurrence of surface defects in steel castings in silica sand molds chemically linked by cold cure process. The methodology used the experimental design with split plot, being considered in the study the resin percentage factors in the mold formulation, addition of iron oxide, type of paint, the paint application method, amount of ink layers, use of hot air along the lines and waiting time of the mold before casting. They were analyzed as response variables erosion defects, sand inclusion, penetration, porosity and surface finish. Tensile strength tests were performed to evaluate the influence of factors on mechanical parameters and the microstructural parameters were carried out the analysis of X-ray diffraction, scanning electron microscopy (SEM) and thermal analysis (TG / DSC / dilatometry). The results elucidate that for the faulty erosion, the only significant factor with a 95% confidence level was the type of ink and the ink alumina-based superior results obtained. For the sand inclusion of defect, there were three significant factors, with best results obtained with alumina-based paint and spray applied using hot air in the mold before casting the metal. For the defect penetration, there were four significant factors, the best results being achieved with 0.8% of resin and addition of iron oxide in the molding formulation, the paint being applied by brush and standby time of 24 hours before leak. For the defect porosity with a 95% confidence level, no significant factors. For the defect surface finish, the best results were achieved with the 0.8% formulation of the resin in the mold and application of the paint brush. To obtain the levels of the factors that optimize all defects simultaneously, we performed a weighted average of the results of each type of fault, concluding that the best levels of the factors were: 0.8% resin and addition of iron oxide in the formulation of the template, application of two coats of paint applied with a brush or spray, using hot air in the mold before casting and 24 hours of waiting ready the mold before casting. These levels of the optimized factors were used in an experiment to confirm that ratified the results, helping to reduce rework and consequently reducing costs of cast steel parts.

Concentração do óleo de girassol em compostos insaturados utilizando destilação molecular

Vegetable oils are characterized as important raw materials in the supplying of natural substances of interest pharmaceutical, food and cosmetic industry. Sunflower oil stands out for its important composition present in unsaturated fatty acids such as oleic acid (C18:1) and linoleic (C18:2), responsible for many health benefits. The main objective of this study is obtain enriched fractions in unsaturated compounds from refined sunflower oil. The oil used in this study was characterized by the determination of some properties, like iodine number, acid number and viscosity. A transesterification was done to transform the triglycerides into their corresponding methyl esters of fatty acids. These was submitted the molecular distillation process, for present as an efficient alternative to separation and purification of these substances, using high vacuum and low temperatures. Of the esters fractions that was obtained, were analyzed by gas chromatography. The experimental design technique was used to evaluate the influence of the temperature variation of evaporation and condensation system on the percentage obtained residue. The evaporator temperature proved to be the most influential variable on the studied response. The optimized conditions for the answer was studied at 100 °C for evaporator temperature and 10 °C for the condenser temperature. The graph of "split ratio" showed that for the lowest flow feed (1 mL/min) and higher evaporator temperature (110 °C) was obtained in the largest fraction of distillate. It also used the study of the influence of evaporator temperature on the concentration of unsaturated compounds. The best operating conditions for temperature was 90 °C reached 82.21 % of unsaturated compounds. Elimination curves of the unsaturated compounds present in the distillate stream were obtained. The simulation results of the molecular distillation process of sunflower oil showed the concentration profiles for three different feed flow rates. The speed, temperature and thickness profiles of the liquid film were obtained. The speed of the film increases as the fluid flows through the walls of the evaporator, reaching a maximum on length of 0.075 m. The film thickness decreases on the route, since many compounds are volatilized. The result of the temperature profile had to be consistent with the literature reproduced, being constant after reaching the maximum operating temperature in the length of 0.15 m. This study allowed characterizing and focusing, through experimental analysis, unsaturated compounds and observing the sunflower oil´s behavior through process simulation.

Concentração do óleo de girassol em compostos insaturados utilizando destilação molecular

Vegetable oils are characterized as important raw materials in the supplying of natural substances of interest pharmaceutical, food and cosmetic industry. Sunflower oil stands out for its important composition present in unsaturated fatty acids such as oleic acid (C18:1) and linoleic (C18:2), responsible for many health benefits. The main objective of this study is obtain enriched fractions in unsaturated compounds from refined sunflower oil. The oil used in this study was characterized by the determination of some properties, like iodine number, acid number and viscosity. A transesterification was done to transform the triglycerides into their corresponding methyl esters of fatty acids. These was submitted the molecular distillation process, for present as an efficient alternative to separation and purification of these substances, using high vacuum and low temperatures. Of the esters fractions that was obtained, were analyzed by gas chromatography. The experimental design technique was used to evaluate the influence of the temperature variation of evaporation and condensation system on the percentage obtained residue. The evaporator temperature proved to be the most influential variable on the studied response. The optimized conditions for the answer was studied at 100 °C for evaporator temperature and 10 °C for the condenser temperature. The graph of "split ratio" showed that for the lowest flow feed (1 mL/min) and higher evaporator temperature (110 °C) was obtained in the largest fraction of distillate. It also used the study of the influence of evaporator temperature on the concentration of unsaturated compounds. The best operating conditions for temperature was 90 °C reached 82.21 % of unsaturated compounds. Elimination curves of the unsaturated compounds present in the distillate stream were obtained. The simulation results of the molecular distillation process of sunflower oil showed the concentration profiles for three different feed flow rates. The speed, temperature and thickness profiles of the liquid film were obtained. The speed of the film increases as the fluid flows through the walls of the evaporator, reaching a maximum on length of 0.075 m. The film thickness decreases on the route, since many compounds are volatilized. The result of the temperature profile had to be consistent with the literature reproduced, being constant after reaching the maximum operating temperature in the length of 0.15 m. This study allowed characterizing and focusing, through experimental analysis, unsaturated compounds and observing the sunflower oil´s behavior through process simulation.

Análise das principais variáveis na flotação industrial do complexo de mineração de Tapira - MG

Faced with an agribusiness expansion scenario and the increase in fertilizer consumption due to the exponential growth of the population, it is necessary to make better use of existing reserves, by obtaining products of better quality and in adequate quantities to meet demand national. In Tapira Mining Complex, Vale Fertilizantes, the phosphate concentrate is produced with content of 35.0% P2O5 from ore with content of about 8.0% P2O5, which are intended to supply Complex Industrial Uberaba and Araxá Minero Chemical Complex for the production of fertilizers. The industrial flotation step responsible for the recovery of P2O5 and hence the viability of the business is divided into the crumbly, grainy and ultrathin circuits, and, friable and granular concentrate comprise the conventional concentrated. Today only 14.7% of the mass which feeds the mill product becomes, the remainder being considered losses in the process, and the larger mass losses are located in the waste of flotation, representing 42.3%. From 2012 to 2014, the daily global mass recovery processing plants varied from 12.4 to 15.9% while the daily metallurgical recovery of P2O5 from 48.7 to 82.4%. By the degree of variability, it appears that the plant operated under different conditions. Seen this, this study aimed to analyze the influence of operational and process variables in P2O5 mass and metallurgical recoveries of industrial flotation circuits of grainy, crumbly and ultrathin. And besides was made an analysis of the effect of ore variables, as degrees, hardnesse and the ore front 02 percentage, in global recoveries of processing plant and the effect of dosages of reagents in the recoveries obtained from the bench flotation using the experimental design methodology. All work was performed using the historical database of Vale Fertilizantes of Tapira-MG, where all independent variables were dimensionless as the experimental range used. To make the statistical analysis it used the response surface technique and the values of the independent variables that maximize recoveries were found by canonical analysis. In the study of industrial flotation circuit crispy were obtained from 41.3% mass recovery and 91.3% metallurgical recovery P2O5, good values for the circuit, and the highest recoveries occur for solids concentration of the new flotation power between 45 and 50%, which values are assigned to the residence time of the pulp in cells and industrial flotation columns. The greater the number of ore heaps resumed on the higher the mass recovery, but in this scenario flotation becomes unstable because there is enormous weight variation in the feed. Higher recoveries are obtained for mass depressant dosage exceeding 120 g / t for synthetic collector dosage of 11.6%. In the study of industrial flotation circuit of the granulate were obtained 28.3% to 79.4% mass recovery and metallurgical recovery of P2O5 being considered good values for the circuit. Higher recoveries are obtained when the front ore 02 percentage is above 90%, because the ore of this front have more clear apatite. Likewise recoveries increase when the level of pulp rougher step is highest due to the high mass of circulating step receives loads. In the analysis of industrial flotation circuit of the ultrafine were obtained 23.95% of mass recovery, and the same is maximized to depressant dosage and the top collector 420 and 300 g / t, respectively. The analysis of the influence of variables ore, it was observed that higher recoveries are obtained for ores with P2O5 content above 8.0%, Fe2O3 content in the order of 28% forward and 02 of ore percentage of 83%. Hard ore percentage has strong influence on recoveries due to mass division in the circuit that is linked to this variable. However, the hard ore percentage that maximizes recoveries was very close to the design capacity of the processing plant, which is 20%. Finally, the study of the bench flotation, has noted that in friable and granular circuits the highest recoveries are achieved for a collector dosage exceeding 250 g / t and the simultaneous increase of collector dosage and synthetic collector percentage contributes to the increase recovery in the flotation, but this scenario is suitable to produce a concentrate poorer in terms of P2O5 content, showing that higher recovery is not always the ideal scenario. Thus, the results show the values of variables that provide higher recoveries in the flotation and hence lower losses in the waste.

Otimização da co-pirólise de gasóleo pesado com embalagens de PEAD pós-uso utilizando planejamento fatorial

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

Delineamentos ótimos para experimentos farmacocinéticos

Pós-graduação em Biometria - IBB

Produção de ciclodextrina glicosiltransferase por Bacillus sp subgrupo alcalophilus: otimização por planejamento experimental

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)