Orientador: Yoon Kil Chang / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-07-21T21:46:58Z (GMT). No. of bitstreams: 1 Bernussi_AnaLuciaMedeiros_M.pdf: 4591717 bytes, checksum: bcb46b88cacc792de8853cbf12ef0512 (MD5) Previous issue date: 1996 / Resumo: Neste trabalho foi estudado o efeito da introdução de energia de microondas no assamento de biscoito semi-doce duro, no gradiente de umidade, incidência de quebra, qualidade sensorial, medidas instrumentais de cor e textura e medidas físicas de diâmetro, espessura, fator de expansão, perda de peso, volume e densidade. Inicialmente foi utilizado um planejamento fatorial completo para os tempos de exposição em microondas de 15, 20, 30 e 40 segundos nas potências alta e média, após o assamento convencional dos biscoitos (2400C por 4 minutos), visando avaliar o comportamento do gradiente de umidade e umidade global dos mesmos. A partir da análise do modelo ajustado ao primeiro fatorial selecionou-se um segundo plano fatorial com tempos de exposição de 23 e 29 segundos nas potências alta e média de microondas, para proceder às análises tecnológicas do produto. Os biscoitos resultantes destes tratamentos apresentaram redução significativa (p<0,05) de gradiente de umidade e porcentagem de quebra, e não apresentaram diferença sensorial significativa em relação ao produto padrão. As análises de textura mostraram que todos os tratamentos são iguais entre si e significativamente menos duros que o padrão. Com relação a cor, os produtos submetidos em potência média (23 e 29 segundos) não diferiram significativamente do padrão enquanto que em potência alta (23 e 29 segundos) foram iguais entre si, mas diferiram do padrão. Os biscoitos assados em fomo elétrico convencional a 2400ºC por 4 minutos e submetidos à energia de microondas por 29 segundos em potência média, apresentaram redução significativa no gradiente de umidade (de 2.16% para 0.88%) e na incidência de quebra (de 41.7% para zero). A medida instrumental de cor dos biscoitos não diferiu (p<0.05) d<'>produto padrão, e a textura (dureza) daqueles foi significativamente menor (1207.59g) comparada ao padrão (1601.35g). O valor de fator de expansão (DIE) para biscoitos padrão (11.3) foi significativamente maior do que o tratamento com microondas (10.7), mostrando que á energia de microondas exerce um efeito de encolhimento no produto. Com relação à perda de peso, os resultados evidenciaram que a retirada da umidade residual pela ação das microondas aumenta a perda de peso do produto (de 0.910 para 0.956). No entanto, a diferença de peso não foi suficiente para distinguir as amostras (padrão e microondas) com relação à densidade. Portanto, concluímos que a introdução da energia de microondas no pós-assamento de biscoitos foi capaz de eliminar o problema de fissura do produto através da diminuição do gradiente de umidade dos mesmos, preservando sua qualidade sensorial e alterando muito pouco as propriedades físicas do produto. / Abstract: In this work, the effect of the introduction of microwave energy in the post-baking of hard semi-sweet biscuits, on humidity gradient, incidence of checking, sensory profile, instrumental measurements of colour and texture, and physical diameter, thickness, expansion ratio, loss of weight, volume and density was studied. A complete factorial plan was used initially at 15, 20, 30 and 40 seconds with high and medium power of microwaves in the post-baking (240°C/4min) of biscuits, in order to evaluate the humidity gradient and global humidity. Based on this first factorial ajusted model a second plan was selected at 23 and 29 seconds of high and medium microwave power exposure, in order to carry out a complete analysis of the products. The resulting biscuits showed a significant reduction (p<0.05) in the humidity gradient and percent of checking, and showed no significant sensory difference with respect to the standard product. The texture analyses showed no difference between the treatments, but all were less hard than the standard: With respect to colour, the products submitted to medium microwave power exposure (23 and 29 sec.) did not differ significantly from the standard, but those exposed to high microwave energy (23 and 29 sec.) did not differ from each other but were different from the standard. The biscuits baked in a conventional oven (electrical heating) at 240°C/4min and subsequently dried with medium microwave power for 29sec, showed a significant reduction in the humidity gradient (from 2.16% to 0.88%) and in the incidence of checking (from 41.7 %to 0%). The instrumental measurement of colour (L parameter) of the biscuits (combined, process) was significantly (p<0.05) equal to the standard sample and that of texture (hardness) was lower (1207.59g) then the standard (1601.35g). The expansion ratio of the standard sample. (11.3) was significantly higher than the combined process sample (10.7), showing a shrinkage effect due to the microwave energy. With respect to weight losses, the results showed us that the residual humidity removal by the action of microwaves increased the product weight loss (from 0.912 to 0.956g). However, the weight difference was not sufficient to differenciate the samples. It was concluded that the introduction of microwave energy in the pot-baking of the biscuits could solve the checking problem through a decrease in the humidity gradient, without causing any sensory changes or notable alterations in the physical properties of the product. / Mestrado / Mestre em Engenharia de Alimentos

Orientador: Antonio Marsaioli Junior / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-07-23T02:47:44Z (GMT). No. of bitstreams: 1 Oliveira_EstevanMartinsde_D.pdf: 9750403 bytes, checksum: dc709488be2a3d64759b2ee68ce4648e (MD5) Previous issue date: 1997 / Resumo: A maior parte da energia suprida na indústria de carnes é consumida nos processos de aquecimento e resfriamento. Desta energia, menos de 60 % é efetivamente aproveitada para o processamento térmico. Esta demanda provém da baixa eficiência dos equipamentos utilizados e rendimento da produção de embutidos cozidos, além da necessidade de considerável espaço físico para sua instalação. A conseqüência disto é a agregação de custos com sistemas de isolamento térmico. As indústrias de grande porte existentes no país, que possuem três linhas de processamento, requerem cerca de 64 funcionários operando. continuamente para atingir uma produção média diária de 80 toneladas. O objetivo deste trabalho foi simplificar o processo minimizando o dispêndio de energia, aumentando o rendimento e com a melhoria da qualidade nutricional e higiênico-sanitária das salsichas industrializadas, além de reduzir o custo operacional, através do desenvolvimento de um sistema contínuo fechado para o processamento de salsichas com aplicação de microondas. O sistema, construído a nível de bancada no Laboratório de Microondas do Departamento de Engenharia de Alimentos FEA/UNICAMP, constituiu-se de um gerador de microondas de 1,9 kW operando na freqüência de 2,45 GHz alimentando um aplicador na forma de guia de onda retangular de alumínio, aonde foi inserido um guia de produto cilíndrico de Teflon. Em uma das extremidades do tubo de teflon foi acoplada uma extrusora construída em aço AISI 304, com desenho apropriado para a co-extrusão contínua de salsichas revesti das de um filme de colágeno/metilcelulose, antes do cozimento e pasteurização por microondas. A emulsão cárnea foi extrudada através de uma bomba positiva. O filme de colágeno/metil-celulose e o agente .de coagulação foram administrados por meio de duas bombas peristálticas. Os ensaios de cozimento foram programados com a aplicação de potências de 0,4 kW a 1,8 kW e vazões de emulsão cárnea variando desde 2,35 até 30 kg/h. Os produtos obtidos foram comparados em cor, aparência, textura, composição e qualidade microbiológica com salsichas de igual formulação porém industrializadas por processos convencionais. Os resultados obtidos demonstraram que as salsichas tratadas à densidade de potência de 170,14 Wh/kg apresentaram melhor aparência, cor e textura do que os demais tratamentos. Em comparação com os produtos industrializados, diferiram quanto à uniformidade da superfície externa pela presença de irregularidades no filme de recobrimento e textura mais rígida. Além disto, sofreram segmentação em função da presença dos vapores gerados durante o cozimento dentro do guia de produto, além da focalização de microondas no centro do produto e concentração de sal no agente coagulante. A qualidade microbiológica do produto processado por microondas foi comparável com os resultados obtidos pelo aquecimento convencional, predominando a flora láctica. O gasto energético estimado com bases no protótipo e extrapolado para escala industrial, para a etapa de cocção, equivale a 18,98 da energia gasta no processo convencional. O sistema necessita ser melhorado quanto ao desenho da. extrusora, à dimensão da câmara de aplicação do filme de recobrimento e a exaustão dos vapores de cozimento, para sua otimização / Abstract: The meat industry expends most of the supplied energy in the heating and cooling processes. Less than 60% of the generated energy are directly useful for the heat process. Such requirements have been originated from the low efficiency of the industrial equipment available and the low yielding of the cooked sausage production rate. . Furthermore, the processing lines need a very large installation area bringing about high expenses for the overall systems thermal insulation. The large scale meat industries prevailing in the country, having an average of three processing lines require an operating labor amounting to 64 employee per shift in a continuous way to reach an the average target capacity of 80 ton daily. The objective of this work was to simplifying the plant processes and operations in order to minimize the energy expenses, increasing capacity ratio, improving the nutritional quality and sanitation conditions of industrialized sausages and lowering operation costs through the application of a continuous microwave and closed system for processing sausages. The type of microwave system setup was bench scale, at the Microwave Laboratory of the Food Engineering Department (FEA/UNICAMP/SP-BR). It consisted of one 1,9 kW high voltage generator and launcher at 2,45 GHz coupled to an aluminum waveguide type applicator internally holding a Teflon cylindrical product tube. An extruder made of AISI 304 stainless steel was designed to be coupled to one end of the Teflon tube, and capable of extruding the meat emulsion with simultaneous coverage of colagen-metylcellulose, emulsion, before cooking and pasteurizing into the microwave system. The meat emulsion was pumped by a progressive cavity pump and the collagen emulsion and coagulation solution were pumped by two peristaltic pumps. The cooking stages were programmed with power densities ranging from 0,4 kW to 1,8 kW under the flow rates from 2,35 to 30 kg/h. The final products were compared by color, appearance, texture, composition and microbiological quality to the sausage of the same formulation obtained by the conventional process. The results showed that sausage treated with 170,4 Wh/kg power density had the best appearance, color and texture as compared to the other treatments. Differences occurred in relation to the industrialized products concerning both to the surface uniformity, due to the rugosity of covering film, and to the segmentation caused by the vapor pressure during the cooking process, in the addition to the problem of focusing energy at the center of the product and salt concentration of the coagulating solution. The microorganism counting of the final microwaved product was similar to the industrialized product heated by the conventional process, with predominance of lactic microorganisms. The supplied energy predicted on the basis of the prototype operation and converted to industrial scale for the cooking step was equal to 18,98 % of the conventional process. The system needs to be improved as regards. to the extruder design, the dimension of the film application chamber and the sizing of the exhaustion chamber for the generated vapors. The coagulating salt solution must be eliminated / Doutorado / Doutor em Engenharia de Alimentos

Orientador: Antonio Marsaioli Jr. / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-07-27T02:06:12Z (GMT). No. of bitstreams: 1 Arevalo_ZildaDoratiottodeSalles_M.pdf: 11966297 bytes, checksum: aef10e426c07a6b1dd7a15f703e3ab37 (MD5) Previous issue date: 2000 / Resumo: A utilização de leveduras, em especial Saccharomyces cerevisiae, como fonte alimentícia,cresceu nos últimos anos. Contrariamenteao caso da levedura destinada à indústria de fermentação, a levedura alimentar deve se apresentar biologicamente inativa, preservando seu alto teor protéico e vitamínico, de forma a poder ser aproveitada tanto para ração animal quanto para o consumo-humano. A produção industrial de leveduras e seu uso como complemento alimentar pode amenizar os problemas agropecuários devido ao clima e sazonalidade de culturas. Se um método de conservação for acoplado à produção, é possível ainda propiciar um fornecimento equilibrado ao mercado consumidor através do controle de estoques. Neste contexto, a operação de secagem se toma atraente pois coloca a biomassa de leveduras sob uma forma física que facilita a estocagem, o transporte e a comercialização. Por outro lado, poucas informações existem sobre o comportamento de leveduras quando submetidas à ação do calor visando sua secagem e inativação simultâneas, bem como das conseqüências sobre o produto final. No presente trabalho, tratou-se de verificar os efeitos das microondas sobre a termolisação da levedura obtida da usina de álcool. Efetivou-se uma série de tratamentos térmicos com forno de microondas, sob temperaturas de 80, 90, 110, 120 e 1250 C, em tempos de 15 e 30 minutos. Procurou-se colocar em evidência o efeito da termólise das células de levedura,fenômeno provocado pela ação do calor. Essa termólise foi conhecida através da avaliação da digestibilidade da proteína, rendimento da extração e da viabilidade celular. Foram conseguidos valores de digestibilidade na faixa de 32 a 85%, com 38% de extração da proteína e zero de viabilidade das células. / Abstract: The use of yeasts, especially Saccharomyces cerevisiae, as a food source, has grown considerably in the last few years. Contrary to those destiIled for industrial fermentation, yeast for food must be biologically inactive, but preserving its high protein and vitamin content, such that it can be used for both animal feed and human consumption. The industrial production of yeasts and their use as a food supprement, could ease the problems faced by the agrarían and animal farming sectors due to the climate and seasonal aspects of other cultures. If a preservation method were coupled to production, this could allow for a balanced supply to the consumer market by controlling stocks. In this context a drying operation would be an attractive alternative, since it would present the yeast bíomass in a physical form which facilitates storage, transport and ommercialization. In this study, a series of heat treatments in a microwave oven were applied, using temperatures of 80, 90, 110, 120 and 125°C for either 15 or 30 minutes. Evidence of thermolysis of the yeast cells as a result of the heat treatment, was searched for. Such thermolysis can be recognized trom an evaluation of protein digestíbility, extraction yíeldand cell viabilíty. In this study the following parameters were obtaíned: 32-85% protein dígestibility, 38% proteín extraction and zero cell víability. / Mestrado / Mestre em Engenharia de Alimentos

Orientadores: Antonio Marsaioli Jr., Hilary Castle de Menezes / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-07-29T03:45:05Z (GMT). No. of bitstreams: 1 Canto_MartaWeberdo_D.pdf: 58370719 bytes, checksum: 428c2c874411981c53d63ba06bc39bee (MD5) Previous issue date: 2001 / Resumo: Este trabalho teve como escopo contribuir com um maior conhecimento sobre a aplicação da tecnologia de microondas, na torração de café, em comparação ao método convencional, nas diferentes qualidades de cafés arabicas (duro para melhor, mole e estritamente mole). Para este fim, foram desenvolvidas condições experimentais para a torração dos grãos de café por microondas a 3500W, 3700We 3850W, na freqüência de 2450 MHz, em um secador rotativo combinado a ar quente, em planta piloto, e para a torração por método convencional [doméstico e rápido (industrial) a 210°C e 220°C], em um torrador de prova de café. o sistema de aquecimento por microondas promoveu um aumento de qualidade no café duro para melhor, menor qualidade de café neste estudo, quando torrado à potências de 3500W e de 3700W, passando de uma resposta sensorial de café duro para melhor com acidez forte para café mole com acidez considerável. Todavia, no café mole, de maior qualidade que café duro para melhor, as microondas apenas proporcionaram a manutenção desta mesma qualidade na potência de 3500W, e uma diminuição desta a 3700W. Nas condições estudadas, não foi possível torrar o café estritamente mole, por este sistema de aquecimento não convencional. Assim, a tecnologia de microondas, desponta como um potencial de desenvolvimento, principalmente para a aplicação em cafés verdes de menor qualidade. Os parâmetros físicos [densidade aparente, diâmetro do grão, grau de inchação, aumento de volume e aumento de tamanho do grão, atividade de água, pH, concentração iônica, cor CIELAB e perda de peso] do café verde e torrado foram avaliados nas diferentes condições de aquecimento convencional e de microondas. As propriedades dielétricas (coeficiente de atenuação, profundidade de penetração, coeficiente dielétrico, fator de perda dielétrica, tangente de perda dielétrica, coeficiente de fase, velocidade de fase, condutividade dielétrica, intensidade de campo elétrico, energia dissipada por volume, fator de perda dielétrica efetiva e tangente de perda dielétrica efetiva) do café também foram determinadas a fim de se avaliar o seu comportamento sob a ação das microondas, e relacioná-Ias com o processo de torração por microondas. A presença de cafeína e dos ácidos 5-cafeoil quínico e caféico foram determinados por CLAE, no café verde e torrado, de maneira a, relacioná-Ios com os diferentes processos de torração e as diferentes qualidades de café arabica. Testes sensoriais foram realizados por classificadores e provadores de café. A utilização das propriedades dielétricas para a avaliação do processo de microondas permitiu uma maior compreensão dos fenômenos que ocorreram durante a torração do café. E desta maneira prever e avaliar o comportamento do café, frente a um determinado campo eletromagnético. No grão verde de café duro para melhor, uma maior densidade aparente média em um maior diâmetro de grão, ou seja, uma estrutura de grão verde mais compactada em relação as outras qualidades de café, reportou em termos de propriedades dielétricas, uma maior constante de atenuação, menor profundidade de penetração, menor impedância intrínseca (maior reflexão e menor transmissão), maior coeficiente dielétrico, maior perda dielétrica, maior condutividade dielétrica, maior coeficiente e velocidade de fase, em uma menor tangente de perda dielétrica. Estas em diferentes potências de microondas, no café torrado, resultaram em uma menor taxa de aumento de temperatura, menor intensidade de campo elétrico (Erms) a 3500 W e 3700 W, menor perda de peso (mas em valores de menor luminosidade para L*) em comparação ao café mole. A resposta sensorial para estes cafés torrados a 3500W e a 3700W foi de, cafés moles com acidez considerável. / Abstract: The objective of this study was to contribute a greater knowledge about different coffee roasting processes by both conventional and microwave methods, comparing the effects on different qualities of arabica coffee (hard to better, soft and very soft). Thus experimental coffee roasting conditions were developed [domestic and rapid (industrial) at 210°C and 220°C] using a laboratory scale roaster, and by microwaves at 3500W, 3700Wand 3850W at a frequency of 2450 MHz, in a pilot rotary dryer combined with hot air. The heating system using microwaves resulted in an increase in quality in the lowest quality coffee sample studied (hard to better), when roasted at 3500W and at 3700W, improving from a classification of hard to better with strong acidity to soft with considerable acidity. However, with the soft coffee sample, the use of microwaves at 3500W only maintained this classification, and at 3700W, resulted in a decrease in quality. Under the conditions studied, it was not possible to roast the very soft coffee sample using microwaves. Thus a technology with potential for development, especially for application in lower quality coffees, was demonstrated. The physical parameters [apparent density, bean diameter, bean swelling, increase in volume and size, water activity, pH, ionic concentration, CIELAB colour and loss of weight] of the rawand roasted coffees, were evaluated for the different heating conditions by both conventional and microwave systems. The dielectric properties (attenuation coefficient, depth of penetration, dielectric coefficient, dielectric loss factor, dielectric loss tangent, phase coefficient and velocity, dielectric conductivity, electric field intensity, energy dissipated per volume, factor and tangent of the effective dielectric loss) of the coffees were also determined, in order to evaluate the behaviour under the action of microwaves, and relate this to the microwave roasting process. Caffeine, 5-caffeoylquinic acid and caffeic acid were determined in both the raw and roasted coffees by HPLC, so as to relate them to the different roasting processes and to the different qualities of arabica coffee. Sensory tests were carried out by qualified coffee tasters and classifiers. The use of the dielectric properties to evaluate the microwave process allowed for a greater understanding of the phenomena occurring during the roasting of coffee, and thus forecast and evaluate the behaviour of the coffee when submitted to a determined electromagnetic field. In the raw coffee bean of the hard to better sample, a greater mean apparent density in a bean with a greater diameter, that is, a more compact green bean structure in relation to the other coffee qualities, resulted in the following effects on the dielectric properties: a greater attenuation constant, greater depth of penetration, lower intrinsic impedance (greater reflection and lower transmission), greater dielectric coefficient, greater dielectric loss, greater dielectric conductivity, greater phase coefficient and velocity, in a smaller tangent of dielectric loss. These effects, at the different microwave powers, resulted in roasted coffees with a lower rate of temperature increase, a lower intensityo f electric field (Erms)at 3500Wand 3700W and a smaller weight loss (but with lower values for luminosity L*), as compared to the soft coffee. The sensory classification of these coffees, roasted at 3500W and at 3700W, was soft coffees with considerable aeidity. The hard to better eoffee roasted at 3500W, exhibited a greater L* and greater "f' factor, a greater degree of thermal destruction on the bean surface as compared to that in the internal part of the grain, a greater degree of thermal lack of uniformity. When roasted at 3700W, it showed a lower positive ~L* and lower positive "f' factor, and, together with this, less thermal destruction on the bean surface and a greater degree of lack of uniformity with the thermal treatment. / Doutorado / Doutor em Tecnologia de Alimentos

Orientador: Marco Aurelio Zezzi Arruda / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-07-25T01:06:27Z (GMT). No. of bitstreams: 1 PereiraFilho_EdenirRodrigues_M.pdf: 2114505 bytes, checksum: 86c77ff88ede9e6b4a723f0eb717d3ab (MD5) Previous issue date: 1999 / Mestrado

Orientadores: Theo Guenter Kieckbusch, Evandro Conforti / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-07-13T23:42:49Z (GMT). No. of bitstreams: 1 MarsaioliJunior_Antonio_D.pdf: 11405717 bytes, checksum: 8969c74e5f1dd34b43ce0e58022ac9a3 (MD5) Previous issue date: 1991 / Resumo: O protótipo desenvolvido e apresentado neste trabalho é o resultado da superposição de dois sistemas contínuos de aplicação de energia aos processos de aquecimento e/ou secagem de produtos sólidos granulados : um em que se considera uma câmara de secagem na qual o produto, em contacto direto com um gás circulante,, proveniente de um circuito gerador auxiliar, troca calor com o mesmo ; outro, que se compre de um sistema aonde a energia de microondas gerada e conduzida à cavidade de aplicação, que corresponde deliberadamente à mesma câmara de secagem anterior, na qual a potência pode ser dissipada no produto a ser aquecido. No estudo da câmara buscou-se conciliar os critérios de projeto aplicáveis aos secadores rotativos convencionais com as dimensões recomendadas para os aplicadores de potencia de microondas. Outro objetivo foi o de garantir o confinamento das microondas ao interior do aplicador, evitando qualquer vazamento da energia das mesmas para o meio ambiente. Esta garantia foi conseguida antes mesmo do inicio da fabricação do protótipo, com a construção de um modelo do aplicador cilíndrico, em escala isométrica reduzida, dotado de filtros adequados nas suas extremidades; os filtros foram testados em laboratório quanto à. aua capacidade de reter as microondas, n£o tendo acusado nenhum vazamento significativo de radiação para o ambiente, antevendo~se assim que o protótipo final poderia perfeitamente aer enquadrado dentro das normas internacionais de segurança e homologação. O desenho do conjunto funcional do protótipo e auxiliares, bem como o seu detalhamento, tiveram sequência, passando-se para as etapas de construção, montagem, instalação e colocação em marcha. O Inicio da operação foi acompanhada de ajustes mecânicos, elétricos e de controle, primeiro com o protótipo em vazio, seguindo-se alguns ciclos com produtos específicos. O desempenho do sistema foi satisfatório, principalmente quanto à rapidez dos tratamentos e à aparente qualidade superior das amostras testadas. Um estudo mais específico foi feito da viabilidade operacional do protótipo na inativação enzimática de grãos de soja integral por microondas, analisando-se os aspectos técnicos e econômicos do processo e do produto tratado e comparando-os com os do produto obtido por um meio convencional, adotado em escala industrial. Os resultados deste estudo revelaram condições mais favoráveis 4 nova opção tecnológica das microondas quando comparadas ao processo convencional / Abstract: The developed prototype, presented in this work, results from the overlapping of two continuous systems of energy, application to the heating and/or drying processes of granulated solid products : one, consisting of a drying chamber in which the product is in direct contact with a circulating gas, coming from an auxiliary generating circuit, exchanging heat with it ; the other one, composed of a system in which the microwave energy is generated and guided toward the application cavity, purposely corresponding to the same drying chamber cited before, in which the power can be dissipated into the product to be heated. During the chamber designing, the conventional rotary dryer project criteria and the recommended dimensions for the microwave power applicators were taken into consideration. Care was taken in order to insure that the microwaves were confined to the interior side of the applicator, keeping any microwave energy from leaking to the surroundings. A reduced size isometric model of the cylindrical application cavity, endowed with suitable filters at its extremities, was built before initiating the prototype construction. The filters were tested in the laboratory as to their ability to retain the microwaves, revealing no significant radiation leakage to the surroundings, therefore it was predicted that the final prototype would perfectly comply with the international safety and homologation standards. The functional assembly drawing of the prototype and its ancillaries as well as the detail drawings of the parte proceeded toward the building, assembling, installation and start up steps. The operation beginning was followed up by mechanical, electrical and control adjustments, first by testing the equipment void of product and secondly running a few cycles with specific products. The performance of the system was satisfactory, mainly concerning the processing rates and the apparent superior quality of the treated samples. The prototype was further submitted to a more specific study in order to verify the operational feasibility of applying microwaves to full fat soybean enzyme inactivation. The technical and economical aspects of the process were also analyzed and the treated samples were compared with those obtained from a conventional industrial method. The results favored the new technology using the microwave inactivation process / Doutorado / Doutor em Engenharia de Alimentos

Les procédés de micro-fabrication connaissent actuellement une croissance importante dans les applications industrielles et pour des secteurs majeurs. Parmi les techniques d’usinage en micro-fabrication, le micro-fraisage est sans doute le plus polyvalent que ce soit en termes de matériau usiné ou de géométrie obtenue. La fabrication de micro-fraises est encore limitée par un certain nombre de paramètres (comme le rayon d’acuité d’arête) et demande alors à être optimisée. L’approche utilisée consistant à reproduire à petite échelle ce qui se fait de mieux à une échelle conventionnelle n’est alors plus forcément adaptée. Il en résulte que le micro-fraisage est un procédé encore mal maîtrisé (usure prématurée de l’outil, bris d’outil, trajectoire non maîtrisée, bavures…).L’objectif de la thèse est donc de comprendre les mécanismes mis en jeu lors de l’enlèvement de matière en micro-usinage et d’en établir un modèle permettant de prédire les efforts de coupe selon les conditions choisies et qui permettra par la suite de faciliter l’optimisation de la géométrie des outils coupantDans un premier temps, une étude expérimentale s’attache à observer la micro-coupe élémentaire d’un acier dur à l’aide de dispositifs réalisés dans le cadre de ces travaux. Un premier dispositif permet de mesurer les efforts d’usinage en micro-coupe élémentaire et un deuxième dispositif innovant permet d’étudier la formation du copeau par coupe interrompue.Par la suite, une démarche de modélisation de la micro-coupe élémentaire est proposée en complément de l’étude expérimentale. Une approche par loi de coupe basée sur les résultats des essais de micro-coupe élémentaire permet de modéliser les efforts d’usinage. En complément, des simulations numériques utilisant la méthode SPH donnent aussi des informations intéressantes sur la formation du copeau, notamment au niveau des zones de déformation.Enfin la loi de coupe associée à un modèle géométrique du micro-fraisage permet de prédire les efforts de coupe lors de l’usinage du même acier. Le modèle géométrique basé sur des travaux précédents a été complété pour prendre en compte la flexion d’outil ainsi que le faux-rond. Ce faux-rond est mesuré directement sur la machine à l’aide d’un moyen d’observation spécialement développé. Les résultats obtenus montrent une concordance entre les efforts expérimentaux et les efforts prédits. / Micro-manufacturing processes are undergoing a significant growth in industrial applications and in a number of major sectors. Among the micro-machining techniques, micro-milling is probably the most versatile both in terms of machined material and in terms geometrical achievability. However, micro-end-mill manufacturing is still limited by some parameters (such as cutting edge radius) and needs improvement. The top-down approach used to reproduce what is best from conventional scale to micro-scale is not necessarily suitable. As a result, micro-milling is still a poorly controlled process (tool wear, tool breakage, path control, burrs...).The aim of the thesis is to understand the mechanisms occurring during the material removal with micro-cutting and to propose a model to predict cutting forces according to cutting conditions, which will then make the optimization of micro-end-mills geometry easier.First, an experimental study is used to observe the elementary micro-cutting operation of a hardened tool steel using specially designed devices. A first device is used to measure cutting forces in elementary micro-cutting and a second innovative device is used to study chip formation by quick-stop tests.Then, modelling approaches of elementary micro-cutting are proposed to complete the experimental study. A cutting law approach based on the results of the elementary micro-cutting tests allows the cutting forces to be modelled. In addition, numerical simulations using the SPH method investigate chip formation and particularly deformation and shear zones.Finally, the proposed cutting law combined with a micro-milling geometric model allows the prediction of cutting forces when micro-milling the same hardened tool steel. The geometric model based on previous work has been completed to consider static tool deflection and run-out. This run-out is measured directly on the machine using a specially developed device. The results obtained show a good correlation between experimental and predicted forces.

Electrochemical machining (ECM) is a non-conventional machining technique capable of machining any conductive substrate, regardless of its physical properties e.g. hardness. ECM became an attractive method due to its ability to machine substrates without creating a defective surface layer. ECM utilises electrolysis; a small gap is maintained between two electrodes whilst a favourable potential is applied between them to remove material from the workpiece. The parameters are adjusted to obtain the desired machining results i.e. surface finish, machining resolution and machining rate. Much work has been conducted for the anodic dissolution of stainless steels and brass but little work outside of these materials is available. This work demonstrates the applicability of ECM for a new range of materials; superconductors and semiconductors, along with the application of ECM for medical needle production and an alteration to the machine set up to anodically dissolve titanium metal at reduced potentials. Through a series of electrochemical techniques, namely polarisation curves, machining potentials were defined for a cuprate superconductor and a semiconductor. These were then demonstrated as suitable settings by completing tests on an electrochemical machine. Hypodermic needles were created on an electrochemical machine and polarisation curves of titanium with the addition of ultrasonic vibrations were used to demonstrate the anodic dissolution of titanium at much reduced potentials.

L’hétérogénéité cellulaire au sein d’une même population cellulaire a été observée chez des organismes procaryotes, chez des organismes plus complexes tels que les mammifères et chez les cellules cancéreuses. L’expression des gènes est un phénomène stochastique ou « bruité ». La connaissance, à l’échelle d’une cellule isolée, des variations stochastiques de l’expression génique, ses oscillations dans le temps et en fonction des fluctuations extérieures constitue un enjeu majeur. Elle permettrait de connaitre les mécanismes de croissance, de différenciation et de migration cellulaire et par voie de conséquence de développer de nouveaux outils thérapeutiques. Par ailleurs, les techniques actuelles d’analyses sur cellule unique nécessitent des protocoles longs et laborieux. Cependant, l’avènement des microcircuits dans les années 80, puis celle de la microfluidique dans les années qui ont suivi, ont ouvert les portes des analyses (chimiques, biologiques et biochimiques) à haut débit, sur de très petits volumes (pl à fl). Nous avons développé un microsystème fluidique, permettant la génération de micro gouttelettes ultrastables et facilement manipulables ; et ce, en utilisant les qualités de changement de phase de l’agarose. Par ailleurs, nous avons conçu un system innovant de génération de microgouttelettes le système « push-pull » qui permet de réduire les volumes morts. Le très petit volume des microgouttelettes font d’elles des microréacteurs dans lesquels nous avons pu encapsuler des suspensions d’ADN, puis des cellules isolées, réaliser des réactions biochimiques, et analyser leur transcriptome ; et améliorer encore l’efficacité et l’intérêt des microémulsions, une technique à très haut débit, et en plein essor.L’hétérogénéité cellulaire au sein d’une même population cellulaire a été observée chez des organismes procaryotes, chez des organismes plus complexes tels que les mammifères et chez les cellules cancéreuses. L’expression des gènes est un phénomène stochastique ou « bruité ». La connaissance, à l’échelle d’une cellule isolée, des variations stochastiques de l’expression génique, ses oscillations dans le temps et en fonction des fluctuations extérieures constitue un enjeu majeur. Elle permettrait de connaitre les mécanismes de croissance, de différenciation et de migration cellulaire et par voie de conséquence de développer de nouveaux outils thérapeutiques. Par ailleurs, les techniques actuelles d’analyses sur cellule unique nécessitent des protocoles longs et laborieux. Cependant, l’avènement des microcircuits dans les années 80, puis celle de la microfluidique dans les années qui ont suivi, ont ouvert les portes des analyses (chimiques, biologiques et biochimiques) à haut débit, sur de très petits volumes (pl à fl). Nous avons développé un microsystème fluidique, permettant la génération de micro gouttelettes ultrastables et facilement manipulables ; et ce, en utilisant les qualités de changement de phase de l’agarose. Par ailleurs, nous avons conçu un system innovant de génération de microgouttelettes le système « push-pull » qui permet de réduire les volumes morts. Le très petit volume des microgouttelettes font d’elles des microréacteurs dans lesquels nous avons pu encapsuler des suspensions d’ADN, puis des cellules isolées, réaliser des réactions biochimiques, et analyser leur transcriptome ; et améliorer encore l’efficacité et l’intérêt des microémulsions, une technique à très haut débit, et en plein essor. / In the post-genomic era, it is now critical to characterize living organisms at the singlecell level. CAGE (Cap Analysis of Gene Expression) is a technology developed by agroup of RIKEN instituteto get genome-wide profile of gene expression. It can beused for profiling of gene expression and identifying the TSS (transcription start site)to analyze promoters architecture. By using the CAGE technology, it could be foundthat different tissues and families of genes differentially use distinct types ofpromoters. Applying CAGE technology against single cells is an ideal way tounderstand life phenomenon based on genome and will have a major impact inbiology. To address this, a novel platform to manipulate single cell and analyze itsown transcriptome with higher precision and efficiency is required.This project aims to develop a microfluidic platform to realize the protocol of CAGEtechnology against single cells with higher-throughput and sensitivity overconventional microtube-based way. For this, we encapsulated single cells inmicrodroplets, lysed them, and performed RT reaction in order to sequence andanalyze their transcriptome.

Mechanical micro machining is an emerging material removal process in precision manufacturing industries. There are challenges involved in micro drilling of difficult to cut alloys. These relate to the development of a feasible and reliable manufacturing process given the fragile nature of the micro drill and the poor machinability of difficult to cut materials. Moreover, the established knowledge of macro scale machining may not be directly transferable into micro machining domain. Therefore, mechanical micro machining needs to be adapted to a specific application. Currently, electrical discharge machining (EDM) is an established industrial process for making micro holes in nickel alloys. The mechanical micro drilling process is at present being considered for improved surface integrity, better hole definition and high productivity. Considering the potential of mechanical micro drilling process in nickel based super alloys, the research presented in this thesis focused on developing a novel micro drilling strategy and a process window. Having developed the process window and selected optimum tool geometry, workpiece surface integrity was evaluated at various cutting conditions. Mechanical and microstructural characterization of the modified layers was conducted using electron backscatter diffraction (EBSD), focused ion beam (FIB), backscatter election (BSE), transmission electron microscopy (TEM) and nano-indentation techniques. The mechanisms behind the generation of these modified layers were revealed. The effects of various feedrates, cutting speeds and tool edge radius were analyzed under dry and wet cutting conditions. A new and novel contribution to modified material microstructure analysis was presented in dry and wet drilling conditions. Furthermore, important findings were presented on the tool-chip and tool-workpiece cutting zones. This research provides a comprehensive picture of the surface integrity definition of the micro hole features in drilling nickel based super alloys. Since nickel based super alloys are known for their poor machinability, tool life becomes an important economic variable. For this purpose, tool wear was studied in the micro machining domain. A new tool wear map was developed on a feed-speed plane, identifying low tool wear zones at high productivity. Wear mechanisms were identified which contributed to better understanding of tool-workpiece interactions. A range of different heat resistant and wear resistant coatings were tested which helped identifying the critical material requirements of machining these alloys. Finally, after having developed a complete set of requirements for the mechanical micro drilling process in terms of process window, suitable tool geometry, workpiece surface integrity, tool wear evaluation and selection of suitable coatings for the micro drilling process; the surface integrity produced by mechanical drilling was compared with EDM and laser drilling processes. Mechanical and microstructural character of surface and subsurface layers was assessed. Comparison of surface integrity parameters showed that the mechanical micro drilling process has the potential to benefit industry making micro size holes with better hole definition and surface integrity. This work is an important contribution to industry in that it presents process feasibility assessment and characterization and is regarded by the industrial partners as having achieved Manufacturing Capability Readiness Level (MCRL) 3.