Les procédés de fabrication de pièces mécaniques par enlèvement de matière (tournage, fraisage, perçage, ...) connaissent une utilisation massive dans l’industrie aéronautique et l’automobile. Les pièces obtenues par ces procédés doivent satisfaire à des propriétés géométriques, métallurgiques et à des caractéristiques de qualité. Pour répondre à ces exigences, plusieurs essais expérimentaux basés sur le choix des conditions de coupe sont souvent nécessaires avant d’aboutir à une pièce satisfaisante. Actuellement, ces méthodes empiriques basées sur l’expérience des fabricants et des utilisateurs des outils coupants sont souvent très longues et coûteuses, donnent une large plage de choix des paramètres en fonction de leurs besoins. Toutefois, le coût très élevé d’un essai limite fondamentalement le nombre d’expériences, avoir une pièce respectant les caractéristiques souhaitées avec un coût acceptable devient une tâche difficile. / Manufacturing processes of mechanical parts by removal of material (turning, milling, drilling ...) have extensive use in aeronautic and automobile industry. The components obtained using these methods must satisfy geometric properties, metallurgical and quality characteristics. To meet these requirements, several experimental tests based on the selection of cutting conditions are often necessary before manufacturing. Currently, these empirical methods based on the experience of manufacturers and users of cutting tools (charts, diagrams with experimental findings, ...) are often very lengthy and costly. However, the high cost of a trial limits the number of experiments, so to have a deserted component with an acceptable cost is a difficult task. The importance of cutting conditions monitored by limitations is related to the type of material to be machined, since it determines the behavior of the machining.

A L-asparaginase (EC 3.5.1.1) é a enzima responsável pela hidrólise da L-asparagina em ácido L-aspártico e amônia, sendo utilizada como agente antitumoral e também para reduzir o conteúdo de acrilamida, composto neurotóxico e carcinogênico, presente em certos alimentos processados a altas temperaturas. Atualmente, o número de trabalhos referentes à produção de L-asparaginase por leveduras e fungos é limitado, principalmente quanto à produção da enzima de forma extracelular em fermentação em estado sólido (FES). Assim, o presente trabalho visou avaliar a produção de L-asparaginase extracelular por FES utilizando fungos e leveduras. Foi avaliado um grupo de 10 cepas de microrganismos como potenciais produtores de L-asparaginase extracelular. Na FES empregou-se o bagaço de cana-de-açúcar (80% de umidade relativa) como suporte suplementado com meio Czapek-Dox modificado e essas foram realizadas em frascos Erlenmeyer de 50 mL a 30 °C por 72 horas para leveduras e 96 horas para o fungo A. terreus. A atividade enzimática foi determinada pela metodologia do hidroxamato e confirmada por testes de cromatografia em camada delgada. Após a seleção dos microrganismos produtores de L-asparaginase extracelular, foi testada a influência de diferentes fontes de carbono, fontes de nitrogênio, pH, tamanhos de partícula e temperaturas na produção de L-asparaginase extracelular por FES utilizando um arranjo ortogonal Taguchi L\'16. Após essa etapa de seleção das variáveis foram realizados ensaios visando a otimização do processo, avaliando o efeito da concentração da fonte de carbono e nitrogênio por planejamento composto central rotacional (DCCR) 24. Finalmente, e com as melhores condições, avaliou-se a produção de L-asparaginase em reator em coluna de leito fixo com volume de 180 mL. Dos microrganismos testados na etapa de seleção, o fungo filamentoso Aspergillus terreus CCT7693 demostrou resultados positivos de atividade asparaginolítica, sendo este selecionado para os experimentos posteriores. De acordo com o arranjo ortogonal Taguchi L\'16, a maior produção de L-asparaginase extracelular (112,57 ± 13,65 U/L) foi obtida quando a maltose foi utilizada como fonte de carbono; a glutamina como fonte de nitrogênio (indutor); pH de 5,5; tamanho de partícula inferior a 0,850 mm e temperatura de 25 °C. No DCCR foram determinadas como condições otimizadas uma concentração de amido de 0,54%; ausência de maltose; concentração de L-asparagina de 0,44% e concentração de L-glutamina de 1,14%, obtendo-se uma atividade L-asparaginase máxima de 120,732 ± 16,77 U/L atingindo uma produção 7,39 vezes superior àquela obtida inicialmente (16,34 ± 3,28 U/L). Na etapa de produção da enzima em reator em coluna de leito fixo obteve-se uma atividade enzimática máxima total de 105,3 U/L demonstrando que este novo modo de produção utilizado foi eficaz. Assim, o presente trabalho permitiu avaliar aspectos relacionados com as condições de cultivo e selecionar o fungo Aspergillus terreus CCT7693 como microrganismo produtor de L-asparaginase extracelular por FES, abrindo perspectivas para explorar este sistema visando aumento de escala de produção. / L-asparaginase (EC 3.5.1.1) is the enzyme that hydrolyses L-asparagine into L-aspartic acid and ammonia. It can be used as a chemotherapeutic agent and also to reduce acrylamide concentration, a neurotoxic and carcinogenic compound, present in certain foods processed at high temperatures. Currently, the amount of works related to Lasparaginase production by yeast and fungi is limited, mainly when it comes to extracellular enzyme production under solid-state fermentation (SSF). Thus, the present work aimed to evaluate the production of extracellular L-asparaginase by SSF using fungi and yeasts. The potential to produce extracellular L-asparaginase was evaluated within a group of 10 strains of microorganisms. In the SSF, sugarcane bagasse (80% relative humidity) was used as support, supplemented with modified Czapek-Dox medium, and the fermentations were done in 50 mL-Erlenmeyer flasks at 30 °C, for 72 hours for yeasts and 96 hours for A. terreus fungus. The enzymatic activity was determined by hydroxamate methodology and confirmed by thin-layer chromatography. After the selection of the extracellular Lasparaginase producing microorganisms, the influence of different carbon and nitrogen sources (inductor), pH, particle sizes and temperatures was tested for the extracellular Lasparaginase production by SSF, using a Taguchi L\'16 orthogonal array. After this initial screening of variables stage, assays aiming at optimizing the process were performed, evaluating the effect of carbon and nitrogen source concentration by central composite design 24 (CCD). With the best conditions, the production of L-asparaginase was assayed in a fixed-bed column reactor with a volume of 180 mL. Among the microorganisms tested in the selection stage, only the filamentous fungus Aspergillus terreus CCT7693 showed positive results for asparaginolytic activity, and it was selected for the later experiments. According to orthogonal array Taguchi L\'16, the highest production of extracellular Lasparaginase (112.57 ± 13.65 U/L) was obtained when maltose was used as carbon source; L-glutamine as nitrogen source (inductor); pH 5.5; particle size less than 0.850 mm and temperature of 25 °C. Through CCD, the optimized conditions were set as: 0.54% starch concentration; absence of maltose; 0.44% L-asparagine concentration and 1.14% Lglutamine concentration. The maximum L-asparaginase activity obtained was 120.723 ± 16.77 U/L, reaching a production 7.39 folds higher than an obtained initially (16.34 ± 3.28 U/L). In the stage of enzyme production in a fixed-bed reactor, a total enzymatic activity of 105.3 U/L was obtained, which indicates that the new production mode was efficient. Thus, the present work allowed to evaluate aspects related to the culture conditions and to select the fungus Aspergillus terreus as a microorganism producer of extracellular L-asparaginase by FES, opening perspectives to explore this system, aiming at increasing scale production.

L'objectif principal de ce travail a été d'apporter une nouvelle contribution quant à l'approche de contrôle optimal pendant la phase d'identification. Il s'agissait de trouver la commande à appliquer pendant l'expérience qui permet d'optimiser un critère qui est fonction des sensibilités des sorties par rapport aux paramètres du modèle à identifier. Cette approche couplant contrôleur prédictif sous contraintes et estimateur a résolu en ligne le problème d'identification à chaque instant en utilisant l'observateur. En ce sens, c'est une approche permettant d'automatiser et d'optimiser le design d'expérience, tout en réalisant conjointement l'identification d'un paramètre du modèle spécifié. L'aspect temps réel a été pris en compte dans la formulation de la solution apportée. Dans ce contexte, nous avons introduit deux stratégies de commande pour l'identification optimale. La première était basée sur un modèle de prédiction non linéaire et la seconde sur un modèle linéaire temps variant. Si le temps devient un paramètre critique pour l'implémentation de l'approche, cette dernière vise à réduire le temps alloué à l'optimisation. L'approche d'identification optimale en ligne a été appliquée à deux problèmes concrets du Génie des Procédés (réaction de saponification et cuisson de peintures). Ces exemples ont permis de vérifier en simulation, l'efficacité et la faisabilité de cette approche. / The main aim of this work is to give a new approach of optimal control during the phase of identification. The question is how to tune the control action to be applied during the experiment optimize a criterion which is function of the sensitivities of the mesure with respect to the parameters of the model to be identified. This approach coupling constrained predictive controller and estimator solves on line the problem of identification by using the observer. In that sense, it is an approach allowing an optimal and automatic design of experiment, while performing at the same time the identification of one parameter of the specified model. The real time aspect was taken into account in the formulation of the solution. In this context, we introduced two strategies for optimal identification : the first one is based on a nonlinear model of prediction and the second one is based on a linear time varying model that may be used if the real time aspect becomes a critical parameter for the implementation of the approach. This approach of on line optimal identification was applied on two concrete problems in Chemical Engineering. These examples show the performance and the feasibility of this approach.

Diplomová práce představuje vytvoření softwarového 2D MKP modelu přehrady Slezská Harta v České Republice za pomoci softwaru PLAXIS 2D. V úvodu práce je analýza vodní nádrže, vytvořené jako zásobárna vody a protipovodňové dílo. Analýza sleduje geomorfologii, geologii, konstrukci tělesa hráze, použité materiály a metody, a stávající monitorovací zařízení. Pro pochopení tvorby 2D MKP modelu jsou předloženy a definované metody použitých analýz - metoda konečných prvků, analýza prosakování, materiálové modely, citlivostná analýza. Následně byla definována tvorba struktury modelu - určení posloupnosti použitých analýz, definování vstupních dat a mezních podmínek a tvorba kalibračního segmentu. V závěrečné části práce je analýza dosažených výstupů rozsáhlého testování modelu, jejich korelace s reálnými naměřenými hodnotami a celkové shrnutí přínosu vytvořeného modelu pro jeho využití při předpovídání chování přehrady v extrémních případech.

The methodology of the design of experimnet has become an integral part of the optimisation of manufacturing processes in recent decades. Problems regarding designs of experiments are still up to date, especially because of a variety of approaches to collecting and evaluating data. Scientists in different research and development areas often do not take into account possible shortcommings or even essential assumptions of selected design and/or its evaluation methods. This disertation thesis summarizes theoretical bases of selected designs of experiments. Describes several applications of central composite design on responses regarding wire electrical discharge machining process. And compares different designs of experiment for response surfaces of five parameters with regards to algoritmic selection of statistically signifficant parameters.

This dissertation thesis deals with the development of technology which could tackle two major issues related to biogas plants. These issues concern the insufficient use of waste heat from biogas combustion and its subsequent processing. It also concerns the use of the fermentation residues which are formed in large quantities and whose use is restricted by law. Based on a literary search of separation methods, a vacuum evaporator was selected as the most suitable technology. Its advantages include its simple construction, operational reliability and robustness, low costs of thickening medium pre-treatment, potential for a quick commercial application and, especially, the chance to use a low-potential waste heat. A primary purpose of this technological unit is the reduction in the volume of fermentation residues. Other benefits include the efficient use of waste heat from a biogas plant, which would otherwise be wasted. Evaporators with a low consumption of electrical energy (which is a main product of a biogas plant) seem to be the best option for applications in the biogas plants. Three of these technologies were subjected to a more thorough analysis, which included the development of computational models and their quantification for conditions in a sample biogas plant. A one-stage evaporator with a forced circulation (680 – 712 kWhth/m3, 25.9 – 30.5 kWhel/m3) was evaluated as the least suitable option in terms of energy demands. The energy intensity of a three-stage evaporator with a falling film (241 – 319 kWhth/m3, 12.0 – 23.6 kWhel/m3) and a nine-stage flash evaporator (236 – 268 kWhth/m3, 13.6 – 18.4 kWhel/m3) is significantly lower. A multi-stage flash evaporator (MSF) was then chosen for development and will form the central focus of this thesis. The reasons for the choice are as follows: the low requirements on the heat transfer surface, good operational experience in the field of desalination, its simple construction, modularity and evaporation outside the heat transfer surface. A thorough technical-economic evaluation was also performed on the integration of the evaporator into the biogas plant. The main part of the work included the experimental development of a MSF evaporator prototype. The main objective of this development was to achieve a stable flow rate of the thickening liquid digestate fraction and the continuous formation of the distillate. This was not an easy objective to achieve, especially due to the properties of the liquid digestate, which has a non-newtonian characteristic and increased density and viscosity compared to water. The tendency of the liquid digestate to form foam was also the subject of analysis. The development of the evaporator and first successful operational test are described in the thesis in detail. This required the use of an anti-foaming product. A fully-developed prototype of the MSF evaporator allowed us to achieve continuous operation with a distillate production, reaching from 5 to 10 kg/h at a liquid digestate flow rate of 0.4–0.5 m3/h. The main drawback of this technology is the pollution of the distillate with ammonia nitrogen, and it is for this reason that the basic procedures of its subsequent elimination was selected for further analysis.

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This study had the purpose to further the use of industrial lasers in the manufacturing of hairpin electric motors by optimizing the process of contacting the hairpins. A problem with laser beam welding of copper is the porosity created in the process which can lead to increased resistance of the welded region along with degraded mechanical properties. By experiment this study aimed to find the optimal parameters to reduce the porosity while maintaining all other requirements for the weld. The track of achieving a satisfactory simulation was done to minimize the need of physical experiments which can be argued as a sustainable development aspect. A set of parameters was found that achieved a low volume of pores, a sufficient weld depth and a desirable bead geometry. Some pores still remained, mostly at the endpoint of the laser path which could be caused by the laser shut-off leading to a keyhole collapse enclosing some pores in that region. The simulation showed promising results in welding depth and melt region. Further work on ramping the laser power at the endpoint could be beneficial for eliminating the remaining porosity as well as refining the simulation in terms of porosity.

<div> <p> Aircraft engines require lightweight efficient thermal management devices to improve engine performance at high pressure ratios. Acoustic streaming can provide a viable, lightweight solution to improve the heat exchanger capacity with a reduced drag penalty within engine heat exchangers. This project develops a test section that will experimentally characterize the effect of acoustic streaming on the unsteady heat flux and shear stress within a narrow channel. This is accomplished by careful selection of measurement techniques to monitor the steady and unsteady properties of the flow and iteratively designing the test section with CFD support to converge to an optimal test model. Using CFD support to revise each iteration reduces the experimental cost of developing an effective geometry. </p> <p> Pressure taps and K-type thermocouples are used to monitor the total inlet pressure and temperature as well as the wall surface pressure and temperature. Optical shear stress sensors are selected to monitor the unsteady wall shear stress. A thin film sensor array is designed for high frequency wall temperature measurements which serve the boundary condition for a 1-D heat flux analysis to determine the unsteady heat flux through the wall. The test model consists of two hollow Teflon airfoils that create a narrow channel within a larger flow area. The airfoils create three flow paths within the wind tunnel test section and the area ratio between the measured flow and the bypass flow controls the Mach number of within the measured flow channel. The acoustic waves drive acoustic streaming and are generated by a Rossiter Cavity with L/D =2 which produces pressure oscillations with dominant frequency of 8 kHz in a Mach 0.8 flow. </p> <p> The test geometry successfully achieves <a>Mach 0.8 flow and the 8 kHz signal </a><a href="https://purdue0-my.sharepoint.com/personal/mbutzen_purdue_edu/Documents/MS Thesis/Thesis Living Document.docx#_msocom_1">[BMJW1]</a> from the Rossiter cavity. The successful commissioning sets the stage for future experiments to determine the potential of acoustic streaming as a low weight modification to improve compact heat exchangers. </p> </div> <div><div><div><br> </div> </div> </div>