IC test socket and socket pogo pin are the major cost of consumption parts in IC testing house. Test yield is the key point to determine the profit for IC testing house. When the processing speed of CPU (Central Processing Unit) and GPU (Graphic Processing Unit) are boosting, heat generation and power dissipation became a serious problem for IC testing house. Most package type of CPU and GPU are packed by Flip-Chip BGA type. High temperature will melt the solder ball and cause test socket pogo pin to damage. The excellent cooling capability of impinging jet had been proofed by many literatures in past. In this article, impinging jet applied to IC test handler contact chuck is investigated. The contact chuck had been redesigned with thermal solution and uses a rectangle hot plate to simulate the thermal status of IC testing. A circular air jet impinged on the rectangle hot plate from the topside of contact chuck. Out flow open area, open area on the wall location and the distance between jet nozzle and hot plate are major parameters of this heat transfer problem. Parameter ¡§Z¡¨ is the distance between jet nozzle and hot plate; ¡§D¡¨ is the diameter of circular air jet. As shown in the result, ratio of Z/D and the location of out flow open area on the wall is obvious on heat transfer capability for redesigned contact chuck. Taguchi method and analysis of variance (ANOVA) method help to clarify the weighting of influence. The optimum Z/D is 0.5 and the optimum location of out flow open area is at dual side corner. Heat transfer capability can be improved approach to 70% after optimization. Width and height of out flow open area only made about 5% impact on heat transfer capability.

The purpose of this dissertation is to study the robust control for the smart flexible linkage mechanism. The control of flexible linkage induced inertia force under high-speed rotation is taken into consideration with the system parameter uncertainties such as modeling error, truncation error, and both of control spillover and observation spillover due to the residual modes of structural control problem. Based on the principles of LQ, optimal model following (OMF) and frequency shaping, this study proposes some sufficient conditions of stability criteria for the design of robust controller, respectively. These techniques guarantee that the controlled plant, under both bounded parameter perturbations and model truncation, could remain stable. Meanwhile, searching for the optimal locating positions of sensor and actuator by applying Taguchi method and genetic algorithm (GA) combined technique is further studied. The system is modeled through employing finite element method (FEM), and the limited lower frequency part modes are separated into controlled modes and residual modes. In time domain, at first we design a Luenberger-observer-based robust controller for the finite-dimensional mode plant keeping stability in a specified region. And then, a robust controller with the OMF is designed for the controlled system to achieve the performance as those of the specified optimum model. From the view of frequency domain, the robust controller could also be deigned according to the frequency shaping principle to suppress the exciting effect of higher frequency residual modes, and similarly avoid that the system might be destabilized. Finally, the combination of Taguchi method and GA technique to search the optimal locations for placing actuator and sensor to coincide with the stability and performance requirement is also done. From the computer simulation, the middle point movement of the linkage is obviously well controlled; hence, the designed robust controllers can certainly suppress the affection of parameter uncertainties and the spillover stimulation of residual modes, and can produce satisfactory results.

In this thesis, it is aimed to design lithium extraction from boron clays using statistical design of experiments and robust design methodologies. There are several factors affecting extraction of lithium from clays. The most important of these factors have been limited to a number of six which have been gypsum to clay ratio, roasting temperature, roasting time, leaching solid to liquid ratio, leaching time and limestone to clay ratio. For every factor, three levels have been chosen and an experiment has been designed. After performing three replications for each of the experimental run, signal to noise ratio transformation, ANOVA, regression analysis and response surface methodology have been applied on the results of the experiments. Optimization and confirmation experiments have been made sequentially to find factor settings that maximize lithium extraction with minimal variation. The mean of the maximum extraction has been observed as 83.81% with a standard deviation of 4.89 and the 95% prediction interval for the mean extraction is (73.729, 94.730). This result is in agreement with the studies that have been made in the literature. However / this study is unique in the sense that lithium is extracted from boron clays by using limestone directly from the nature, and gypsum as a waste product of boric acid production. Since these two materials add about 20% cost to the extraction process, the results of this study become important. Moreover, in this study it has been shown that statistical design of experiments help mining industry to reduce the need for standardization.

This thesis reviews Quality Function Deployment (QFD) and its relation with the Total Quality Management philosophy. In particular the thesis focuses on the inherent drawbacks of QFD and it investigates potential techniques and methods that could be integrated with QFD to overcome some of its problems. Fuzzy Logic/Fuzzy Sets and the Taguchi Method are identified as techniques and methods to be incorporated within the QFD process to provide a more consistent, quantitative and rigorous method to analyse subjective data in the QFD charts. Two approaches are developed that integrate Fuzzy Logic and Fuzzy Set theory with QFD to identify and rectify inconsistencies in the input data in the QFD charts. Another approach that integrates the Taguchi Method and QFD is further developed to set more precise technical target values in the QFD chart. Case studies are used to illustrate the results of the developed Fuzzy-QFD and the QFD-Taguchi approaches. The synergistic approaches take into account nteractions between requirements, which are not utilised in the traditional QFD charts. In addition, it was found that the resulting data in the QFD charts are sensitive to the interaction in the correlation matrices, therefore another method is also proposed to detect inconsistencies in the correlation matrices by utilising an inference mechanism and multi-valued logic theory. An integrated systems approach to QFD is eventually developed that forms a synergy between QFD, Fuzzy Logic/Fuzzy sets and the Taguchi Method. This results in a superior approach that combines the inherent benefits of each of the individual approaches. The integrated systems approach to QFD is a generic approach that can be used for other case studies provided that in addition to the relationship matrix and customer importance ratings, the correlation matrices and benchmarking data are readily available. As a result of this research, the subjectivity and ill-defined data in the QFD process have been partially resolved by the application of Fuzzy Logic/Fuzzy sets. The QFD analysis has been made more rigorous by integrating it to more quantitative techniques (Fuzzy Logic/Fuzzy sets) and method (Taguchi Method). It has been identified that demands are dependent on each other in the QFD charts and how including these dependencies in the problem can change the results. This problem has been addressed by considering interactions between the demands in the Fuzzy-QFD and QFD-Taguchi approaches developed. These interactions between demands have been identified and dealt with in the developed approaches, such that they no longer provide sub-optimal solutions.

A method for performing robust optimal design that combines the efficiency of experimental designs and the accuracy of nonlinear programming (NLP) has been developed, called Search-and-Zoom. Two case studies from the RF and communications industry, a high-frequency micro-strip band-pass filter (BPF) and a rectangular, directional patch antenna, were used to show that sensitivity optimization could be effectively performed in this industry and to compare the computational efficiency of traditional NLP methods (using fmincon solver in MATLAB R2013a) and they hybrid method Search-and-Zoom. The sensitivity of the BPF's S11 response was reduced from 0.06666 at the (non-robust) nominal optimum to 0.01862 at the sensitivity optimum. Feasibility in the design was improved by reducing the likelihood of violating constraints from 20% to nearly 0%, assuming RSS (i.e., normally-distributed) input tolerances and from 40% to nearly 0%, assuming WC (i.e., uniformly-distributed) input tolerances. The sensitivity of the patch antenna's S11 function was also improved from 0.02068 at the nominal optimum to 0.0116 at the sensitivity optimum. Feasibility at the sensitivity optimum was estimated to be 100%, and thus did not need to be improved. In both cases, the computation effort to reach the sensitivity optima, as well as the sensitivity optima with RSS and WC feasibility robustness, was reduced by more than 80% (average) by using Search-and-Zoom, compared to the NLP solver.

Use of weight-saving materials to produce lightweight components with enhanced dimensional control is important to the automotive industry. This has increased the need to understand the material behavior with respect to the forming process at the microstructural level. A test matrix was developed based on the orthogonal array of Taguchi design of experiment (DOE) approach. Experiments were conducted for the V-bending process using 6022-T4 AA to study the variation of springback due to both process and material parameters such as bend radius, sheet thickness, grain size, plastic anisotropy, heat treatment, punching speeds, and time. The design of experiments was used to evaluate the predominate parameters for a specific lot of sheet metal. It was observed that bend radius had greatest effect on springback. Next, finite element simulation of springback using ANSYS implicit code was conducted to explore the limits regarding process control by boundary values versus material parameters. 2-D finite element modeling was considered in the springback simulations. A multilinear isotropic material model was used where the true stress-strain material description was input in discrete form. Experimental results compare well with the simulated predictions. It was found that the microstructure of the material used in this study was processed for sheet metal forming process.

[ES] En la presente Tesis Doctoral se investigó la aplicación del proceso de ultrafiltración (UF) y el fenómeno de ensuciamiento de las membranas en la eliminación de sustancias disueltas y coloidales (DCS) de efluentes tratados de la industria papelera (PMTE) para su reutilización en los diferentes procesos de fabricación de papel y cartón reciclado. El objetivo general de esta investigación se dividió en tres partes principales: i) describe cómo encontrar las condiciones óptimas de operación de cuatro parámetros de proceso: presión transmembrana (TMP), velocidad de flujo cruzado (CFV), temperatura y corte de peso molecular (MWCO) para maximizar el flujo promedio de permeado (Jp) y rechazo de la demanda química de oxígeno (COD) y minimizar el descenso del flujo de permeado acumulado (SFD) utilizando el método de Taguchi (Design Robusto) y utility concept aplicado a un proceso de UF a flujo cruzado, para remover DCS de efluentes tratados de la industria papelera, ii) el descenso del flujo de permeado y los mecanismos de ensuciamiento de las membranas de UF ensuciadas con PMTE se examinaron mediante modelos matemáticos semi-empíricos. Los resultados para los diferentes ensayos de UF se expresaron en términos de variación del Jp en función del tiempo para verificar la precisión del ajuste (mayor valor de R2 y menor valor de desviación estándar) de los distintos modelos de Hermia adaptados a flujo tangencial y del modelo de formación de torta en filtración a presión constante ajustados a los datos experimentales, y iii) describe métodos de identificación, caracterización y posibles orígenes de las sustancias contaminantes (foulants) en las membranas de UF. Técnicas como el análisis físico-química, FESEM, SEM-EDS, ATR-FTIR y 3DEEM se llevaron a cabo para comprender qué fracción de los contaminantes son responsables por la formación de incrustaciones en las membranas. Los resultados obtenidos durante la etapa de optimización de parámetros del procesos demostraron que TMP y MWCO tienen la mayor contribución en el Jp y SFD. En el caso de la tasa de rechazo de COD, los resultados mostraron que MWCO tiene la mayor contribución seguida de CFV. Por consiguiente, las condiciones óptimas se encontraron para el segundo nivel de TMP (2.0 bar), el tercer nivel del CFV (1.041 m/s), el segundo nivel de la temperatura (15°C) y el tercer nivel de MWCO (100 kDa). Bajo estas condiciones óptimas de operación Jp, rechazo de COD y SFD alcanzaron respuestas de 81.15 L/m2.h, 43.90% y 6.01 (alrededor de 28.96 % para (FD), respectivamente, valores dentro del rango previsto del intervalo de confianza del 95%. Además, los modelos de Hermia adaptados a UF en flujo tangencial fueron capaces de predecir con gran precisión el descenso del Jp y los mecanismos de ensuciamiento en función del tiempo para todas las membranas seleccionadas (10, 30 y 100 kDa) y bajo diferentes condiciones ensayadas de UF. Por lo tanto, los modelos que presentan un mayor grado de ajuste son el bloqueo completo de poros (coeficiente de determinación R2 >0.97) y bloqueo intermedio (R2 >0.96), seguido por el modelo de formación de torta (R2 >0.94), lo que indica que estés son los principales mecanismos de ensuciamiento de las membranas. Análisis de 3DEEM revelaron que la mayoría de la materia orgánica fluorescentes en las membranas sucias eran proteínas coloidales (componentes similares a proteínas I + II) y proteínas macromoleculares (componentes similares a SMP). Además, polisacáridos (especie celulósica) y sustancias como ácidos grasos y resinosos fueron identificadas en las membranas contaminadas mediante análisis ATR-FTIR. Por fin, análisis SEM-EDS para las membranas ensuciadas con PMTE se detectó concentración de contaminantes inorgánicos (iones metálicos multivalentes) especialmente el Ca2+ que podría acelerar la formación torta en la superficie de la membrana. / [CA] En la present Tesi Doctoral es va investigar l'aplicació del procés d'ultrafiltració (UF) i el fenomen d'embrutiment de les membranes en l'eliminació de substàncies dissoltes i col·loïdals (DCS) d'efluents tractats de la indústria paperera (PMTE) per al seu reutilització en els diferents processos de fabricació de paper i cartó reciclatge. L'objectiu general d'aquesta investigació es va dividir en tres parts principals: i) descriu com trobar les condicions òptimes d'operació de quatre paràmetres de procés: pressió transmembrana (TMP), velocitat de flux creuat (CFV), temperatura i tall de pes molecular (MWCO) per a maximitzar el flux mitjà de permeat (Jp) i rebuig de la demanda química d'oxigen (COD) i minimitzar el descens del flux de permeado acumulat (SFD) utilitzant el mètode de Taguchi (Design Robust) i utility concept aplicat a un procés de UF a flux creuat en escala pilot, per a remoure DCS d'efluents tractats de la indústria paperera (PMTE), ii) el descens del flux de permeat i els mecanismes de embrutiment (fouling) de les membranes de UF embrutades amb PMTE es van examinar mitjançant models matemàtics semi-empírics. Els resultats per als diferents assajos de UF es van expressar en termes de variació del flux de permeat (Jp) en funció del temps per a verificar la precisió de l'ajust (major valor de R2 i menor valor de desviació estàndard) dels diferents models de Hermia adaptats a flux tangencial i del model de formació de coca en filtració a pressió constant ajustats a les dades experimentals, i iii) descriu mètodes d'identificació, caracterització i possibles orígens de les substàncies contaminants (foulants) en les membranes de UF. Tècniques com l'anàlisi física-química, FESEM, SEM-EDS, ATR-FTIR i 3DEEM es van dur a terme per a comprendre quina fracció dels contaminants són responsables per la formació d'incrustacions sobre la superfície i adsorció dins dels porus de les membranes. Els resultats obtinguts durant l'etapa d'optimització de paràmetres del processos van demostrar que TMP i MWCO tenen la major contribució en el Jp i SFD. En el cas de la taxa de rebuig de COD, els resultats van mostrar que MWCO té la major contribució seguida de CFV. Per consegüent, les condicions òptimes es van trobar per al segon nivell de TMP (2.0 bar), el tercer nivell del CFV (1.041 m/s), el segon nivell de la temperatura (15°C) i el tercer nivell de MWCO (100 kDa). Sota aquestes condicions òptimes d'operació Jp, rebuig de COD i SFD van aconseguir respostes de 81.15 L/m².h, 43.90% i 6.01 (al voltant de 28.96% per a (FD)), respectivament, valors dins del rang previst de l'interval de confiança del 95%. A més, els models de Hermia adaptats a UF en flux tangencial van ser capaços de predir amb gran precisió el descens del Jp i els mecanismes de embrutiment en funció del temps per a totes les membranes seleccionades (10, 30 i 100 kDa) i baix diferents condicions assajades de UF. Per tant, els models que presenten un major grau d'ajust són el bloqueig complet de porus (coeficient de determinació R2 >0.97) i bloqueig intermedi (R2 >0.96), seguit pel model de formació de coca (R2 >0.94), la qual cosa indica que estigues són els principals mecanismes de embrutiment de les membranes. Anàlisi de 3DEEM van revelar que la majoria de la matèria orgànica fluorescents en les membranes brutes eren proteïnes col·loidals (components similars a proteïnes I + II) i proteïnes macromoleculars (components similars a SMP). A més, polisacàrids (espècie cel·lulòsica) i substàncies com a àcids grassos i resinosos van ser identificades en les membranes contaminades mitjançant anàlisis ATR-FTIR, tals substàncies exerceixen un paper important en el embrutiment de les membranes. Per fi, anàlisi SEM-EDS per a les membranes embrutades amb PMTE es va detectar concentració de contaminants inorgànics (ions metàl·lics multivalents) especialment el Ca2+ que podria accelerar la formació coca en la àrea de la membrana. / [EN] In this PhD Thesis, the application of ultrafiltration process (UF) and membrane fouling phenomenon used to remove dissolved and colloidal substances (DCS) from paper mill treated effluent (PMTE) for reuse in different recycled paper and cardboard manufacturing processes was investigated. The overall goal of this research has been divided into three main parts: i) describes how to find optimal operating conditions of four controlling parameters, such as transmembrane pressure (TMP), cross-flow velocity (CFV), temperature and molecular weight cut-off (MWCO) for maximizing the average permeate flux (Jp) and chemical oxygen demand (COD) rejection, and minimizing the cumulative flux decline (SFD) using Taguchi method and utility concept for a cross-flow UF in pilot scale, used to remove DCS from a paper mill treated effluent (PMTE), ii) flux decline and fouling mechanisms of UF membranes fouled with PMTE were examined by theoretical modelling. The results from UF tests were expressed in terms of permeate flux (Jp) as a function of time to check modified Hermia's models adapted to crossflow filtration and cake formation in constant-pressure filtration, and iii) describes the Identification, characterization and possible origins of UF membrane foulants. Techniques such as chemical analysis, FESEM, SEM-EDS, ATR-FTIR and 3DEEM analysis were applied to understand which fraction of the foulants caused the fouling. This research found that the TMP and MWCO have the greatest contribution to the average permeate flux and SFD. In the case of the COD rejection rate, the results showed that MWCO has the highest contribution followed by CFV. The optimum conditions were found to be the second level of TMP (2.0 bar), the third level of the CFV (1.041 m/s), the second level of the temperature (15°C), and the third level of MWCO (100 kDa). Under these optimum conditions Jp, COD rejection and SFD resistance of 81.15 L/m2/h, 43.90% and 6.01 (around 28.96 % of (FD), respectively, were obtained and they were within of the predicted range at the 95% confidence interval. Furthermore, the results showed that the predictions of the modified Hermia's models adapted to cross-flow UF had good agreements with experimental data, under different conditions tested for PMTE. Therefore, it can be concluded that for all cases the best fit (higher accuracy) to the experimental data corresponds to the complete (coefficient of determination R2 >0.97) and intermediate (R2 >0.96) blocking, followed by the cake layer formation (R2 >0.94). Moreover, measurements of particle size distribution and zeta potential near the isoelectric point, showed a substantial reduction in colloidal compounds. The 3DEEM analysis revealed that the majority of the organic foulants with fluorescence characteristics on the fouled membranes were colloidal proteins (protein-like substances I+II) and macromolecular proteins (SMP-like substances). Further, polysaccharide (cellulosic specie), fatty and resin acid substances were identified on the fouled membrane by the ATR-FTIR analysis and they play an important role in membrane fouling. In addition, the membrane SEM-EDS analysis showed accumulate and adsorbed onto the membrane surfaces of inorganic foulants, such as multivalent metal ions and especially Ca2+ (acts as a binding agent) that could accelerate cake layer formation on the membrane. / Santos Sousa, MR. (2020). Optimization of Operation Parameters in Ultrafiltration by Experiment Design, Mathematical Modelling and Fouling Characterization of the Membranes Used to Remove Dissolved and Colloidal Substances from a Treated Paper Mill Effluent [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/155975

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: Polysulfone hollow-fibre membranes were fabricated via the dry-wet solution spinning technique. The objective was to demonstrate the influence of the various fabrication parameters on the diameter and mechanical properties of the hollow-fibre membranes and to optimize the spinning process by controlling these parameters with a computer control system. The effects of the operation parameters were investigated using an experimental design based on a fractional factorial method (Taguchi’s design of experiments). The parameters that were considered are the spinneret size, dope solution temperature, bore fluid temperature, coagulation bath temperature, dope extrusion rate, bore flow rate and the take-up speed. A new pilot solution spinning plant was installed and upgraded, and a computer control system, based on LabView, was developed to control, monitor and log the experimental data. The diameter of the hollow-fibres were determined using a scanning electron microscope (SEM) while the mechanical properties were measured using a tensile tester. The effects of diameter size and wall thickness of the hollow-fibres on the performance of the membranes were studied. The results showed the significance of the fabrication parameters that dominate the diameter and strength of the hollow-fibres. / AFRIKAANSE OPSOMMING: Polisulfoon holvesel membrane is met ‘n droë-nat oplossingspin proses vervaardig. Die doel hiermee was om die invloed van verskeie vervaardigingsparameters op die deursnee en meganiese eienskappe van die holvesel membrane te demonstreer asook om die spin proses te optimeer deur gerekenariseerde beheer van die aanleg. ‘n Eksperimentele ontwerp, gebaseer op ‘n gedeeltelike faktoriaal metode (Taguchi se eksperimentele ontwerp) is gebruik om die invloed van die vervaardigingsparameters te ondersoek. Die parameters wat oorweeg is, is spindop grootte, materiaal temperatuur, boorvloeistof temperatuur, stolbad temperatuur, materiaal ekstrusie tempo and opwen spoed. ‘n Nuwe oplossingspin loodsaanleg was geïnstalleer en opgegradeer en ‘n rekenaar beheerstelsel, gebaseer op LabView, is ontwikkel om die aanleg te beheer, moniteer en eksperimentele data te stoor. Die deursnee van die holvesel is gemeet met ‘n skanderingelektron mikroskoop (SEM) terwyl die meganiese eienskappe bepaal is met ‘n trektoets apparaat. Die effek van die deursnee en wanddikte van die holvesels op die werkverrigting van die membrane is ook bestudeer. Die resultate toon watter vervaardigingsparameters is beduidend vir die deursnee en sterkte van die holvesels.

This thesis focuses on the development of a novel polymer based housing for power thyristor devices typically used in long distance high voltage direct current (HVDC) transmission. Power thyristor devices used in HVDC power conversion stations are typically packaged in a hermetically sealed ceramic housing and have demonstrated an excellent history of reliability and performance. However, to avoid increasing the number of thyristors in future higher powered HVDC schemes thyristors having higher power ratings at 8.5 kV and sizes at 125 mm and 150 mm diameters are sought for implementation to achieve higher transmission ratings of, for example, 4000 A at +/- 800 kV. The main disadvantages of such large ceramic-based packages are higher processing cost and weight whilst robustness is also a concern. To overcome these issues, replacing the current ceramic housing with a polymeric material has been investigated in this project. The advantages it is anticipated such packages will provide include lower cost, less weight, robustness, recyclability, etc. However, some challenges it will also offer are: non-hermeticity i.e. polymers are moisture and gas permeable, potentially more complex manufacturing routes, and different electrical, mechanical and thermal properties compared to ceramic materials. The work presented in this thesis was part of a larger project where these challenges have been addressed by developing and testing a prototype polymeric thyristor housing. The prototype is aimed at demonstrating that polymer packages can deliver performance and reliability comparable to, if not better than, current ceramic packages. In this thesis, it is the package development and reliability related studies that are discussed. Because the housings will experience severe electrical stresses and various thermal excursions during their service life, the electrical and thermo-mechanical behaviour of the polymer housing was studied using finite element analysis to gain an understanding of the effects of various design variables and materials properties on performance and the tradeoffs between performance and manufacturability. From these modelling studies, design guidelines have been established for the future development of polymer housings. On the other hand, to identify the physics-of-failure of the prototype that was manufactured as part of the project, accelerated life tests were performed to study its reliability. The knowledge gained from the polymer prototype development was then applied to the design of a larger 125 mm diameter housing using the Taguchi method of experimental design.

Atualmente, as microalgas têm se mostrado uma matéria prima de interesse para a produção de biocombustíveis, por ser uma fonte renovável, não poluente e por não competir em áreas de cultivos de alimentos. No entanto, há a necessidade de se explorar fatores e metodologias na produção de biodiesel de microalgas para que o processo seja viabilizado. Este estudo buscou potencializar o processo de transesterificação direta (extração e reação simultaneamente) da biomassa da microalga Chlorella minutíssima para a produção de ésteres etílicos brutos tendo em vista a produção de biodiesel. O processamento direto (in situ) investigou separadamente o uso da biomassa seca e úmida, sob os efeitos dos fatores etanol, clorofórmio e ácido como catalisador. A metodologia de Taguchi foi utilizada como planejamento de experimentos para potencializar a conversão e rendimento mássico em ésteres etílicos. A partir da biomassa seca, analisadas as razões de etanol/biomassa de 100, 50, 25 e 10 mL/g teve a maximização dos resultados utilizando 25 mL de etanol (86,16% em massa com 96% de conversão) e 50 mL de etanol (104% em massa com 88% de conversão), ambas, com 5 mL de clorofórmio e 1mL de ácido sulfúrico por grama de biomassa. Posteriormente, com a inclusão dos catalisadores ácidos HCl e H2SO4 como variável, investigou-se o a reação de transesterificação in situ a partir da biomassa úmida (84% em base seca). Ambos ácidos demonstraram não ter efeito sobre as repostas. A maximização tanto do rendimento mássico quanto da conversão (131,5% em massa com 84% de conversão), bem como produzir a maior quantidade de ésteres com a menor uso de reagentes, utiliza a concentração do ácido a 0,6 mol/L, 25 mL de etanol e proporção de 1:10 de clorofórmio. Tanto a partir da biomassa seca quanto a partir da biomassa úmida, a metodologia de Taguchi foi capaz de determinar os melhores ajustes das condições reacionais para a síntese de ésteres etílicos brutos sem a necessidade de aplicar condições reacionais limitadas pela construção ou segurança do projeto como irradiação de micro-ondas ou condições supercríticas. / Currently, microalgae are considered an interest feedstock for the biofuel production, since they correspond to a renewable and non-polluting source, not competing with food crops areas. However, there is a need to explore factors and methodologies in the production of microalgae biodiesel to enable the process. This study aimed to enhance the direct transesterification process (simultaneous extraction and reaction) of the Chlorella minutíssima microalgae for the crude ethyl esters production in order to produce biodiesel. The direct processing (in situ) was investigated separately dry and wet biomass use under the effects of ethanol, chloroform and acid as a catalyst. The Taguchi methodology (design of experiments) was used to increase conversion and ethyl esters mass yields. The ethanol ratios 100, 50, 25 and 10 mL/g were analyzed from dry biomass. The results were maximized using 25 mL of ethanol (86.16% by mass with 96% conversion) and 50 mL (104% by mass with 88% conversion) with 5 mL of chloroform and 1 mL of sulfuric acid per gram of biomass. Subsequently, with the inclusion of acid catalysts HCl and H2SO4 as a variable, the in situ transesterification reaction of wet biomass (84% on dry basis) was investigated. In both cases, the acids showed no effect on the responses. Mass yield and conversion were maximized (131.5% by mass with 84% conversion), as the highest number of esters with the lowest use of reagents, take 0.6 mol/L acid concentration, 25 mL ethanol and 1:10 chloroform ratio. Taguchi methodology was able to determine the best reaction conditions adjustments for crude ethyl esters synthesis from dry biomass and wet biomass were met without the need to apply reaction conditions limited by the construction or project safety, as microwave irradiation or supercritical conditions.