A processing procedure for the manufacture of directly acidified cottage cheese curd from 16% total solids ultrafiltered retentate was developed. The effects of preacidification of skim milk before ultrafiltration and heat treatment of retentate were investigated to improve the functional and sensory qualities of retentate curd. Retentate directly acidified with phosphoric acid and glucono-delta-lactone to pH 4.7 formed a dense, rubbery curd that could not be handled well in a vat. A heat treatment of 71.1°C for 30 min applied to the retentate resulted in a curd with acceptable handling properties. However, this heat treatment caused the curd to shift in pH, become translucent in appearance, and have a pasty texture. Preacidification of the skim milk to pH 5.8 12 h prior to ultrafiltration, and a less severe heat treatment of 71.1°C for 6 min made a stable curd with good sensory quality. A 3 x 4 x 3 randomized split block design experiment was done to test the effects of preacidification and heat treatment on the properties of retentate curd. Skim milk was pasteurized at 62.8°C for 30 min and split into three lots which were unacidified, phosphoric acid added to pH 6.2, and phosphoric acid added to pH 5.85. The three lots of skim milk were ultrafiltered at 54.4°C to 16% total solids. Each lot was divided into four treatments which were unheated, heated to 71.1°C for 7 s, 76.7°C for 7 s, and 82.2°C for 7 s. Each vat was replicated three times. Cottage cheese pH, total solids, and six sensory attributes were measured. Finished cottage cheeses were evaluated by an expert panel of five judges. Total solids, protein content, and fines content of the whey were also measured. Preacidification treatment at pH 6.2 enhanced curd structure, which increased solids recovery, reduced fines, and improved curd appearance, firmness, and texture. Heat treatments caused softening of the curd and increased moisture content in the curd. Excessive heat treatment caused shattering, fines, and mealiness. The best curd from the experiment was produced from pH 6.2 retentate heat treated at 71.1°C for 7 s. Whey proteins decreased in wheys from retentates heat treated at 76.7°C for 7 sand 82.2°C for 7 s. The effects of heat treatment were more pronounced with increasing acidification.

Assim como em qualquer processo de fabricação, a qualidade do produto final deve estar aliada à otimização dos custos do processo, portanto, deve-se conhecer os fatores que alteram as propriedades do produto e que possam causar alguma influência indesejada. A trefilação de barras de aço é usualmente utilizada para conferir precisão dimensional e melhores propriedades mecânicas ao material. Um dos grandes problemas encontrados na fabricação de eixos através deste processo é o aparecimento de distorções de forma após o tratamento térmico. Tais distorções estão diretamente ligadas ao acúmulo de tensões residuais geradas durante as etapas de pré-endireitamento, jateamento e trefilação propriamente dita, modificando o comportamento e resistência mecânica, bem como a resistência à fadiga e à corrosão das peças. Portanto, este trabalho tem por objetivo analisar, através de uma abordagem numérica computacional, a influência de parâmetros de processo e propriedades do material no aparecimento de distorções em barras trefiladas de aço AISI 1045, em função de possíveis fontes geradoras de heterogeneidades, principalmente de tensões residuais durante o processo de fabricação. A análise das tensões foi realizada através da modelagem numérica 3D do processo de trefilação, sendo utilizado o software de simulação numérica computacional DeformTM. Da mesma maneira, foram analisadas as formas de agarre que fornecem a velocidade do processo, a primeira utilizando um puxador na extremidade da barra, a segunda com um puxador envolto movimentando-se ao longo da barra. Através destas análises, verificou-se que a forma de como a barra é tracionada ocasiona uma redução de até 100 MPa nas tensões residuais no centro da barra, o que representa um fator importante no estudo das possíveis causas das distorções. Observou-se ainda que os fatores de velocidade e homogeneidade da lubrificação modificaram o perfil das tensões residuais na barra. Outros parâmetros, como desalinhamento da ferramenta, diferenças de atrito, excentricidade do eixo e curvatura da barra, também foram avaliados, sendo que ambos influenciam consideravelmente na distribuição das tensões residuais ao longo do perfil da barra. Torna-se evidente a importância de um eficiente pré-endireitamento do fio máquina, pois os resultados das simulações com curvatura mostram que a força de trefilação e a distribuição das tensões residuais ao longo da barra trefilada aumentam, bem como a barra apresenta certa curvatura remanescente, para ambas as fieiras com ângulo de 15° e 20°. Sendo assim, tais resultados evidenciam a elevada influência dos parâmetros estudados no aparecimento de distorções no produto final. / As with any manufacturing process, the quality of the final product must be coupled with cost optimization of the process, so you should know the factors that alter the properties of the product that may cause some unwanted influence. The drawing of steel bars is usually used to impart better dimensional accuracy and mechanical properties to the material. One of the major problems encountered in the manufacturing of axes through this process is the appearance of distortion of size and shape after heat treatment. Such distortions are directly linked to the accumulation of residual stresses generated during the stages of pre-straightening, shot blasting and drawing itself, modifying behavior and mechanical strength, residual stresses and resistance to fatigue and corrosion of parts. Therefore, this work aims to examine, through a computational numerical approach, the influence of material parameters and process the appearance of distortions in cold drawn steel bars AISI 1045, due to possible sources of residual stresses during the manufacture. The analysis of strains and residual stresses were performed by 3D numerical modeling of the drawing process, the software being used numerical simulation computational DeformTM. In order to transmit the drawing speed, the forms of grip were analyzed using a first end of the puller bar, the second wrapped with a puller moving along the bar. Since through these analyzes, it was found that as the shape of the bar is pulled up causes a reduction in the residual stress 100 MPa in the center of the bar, which is an important factor in the study of the possible causes of the distortion. As well as factors speed and homogeneity of lubrication significantly altered the profile of residual stresses in the bar. Other parameters, such as misalignment of the tool, friction differences, curvature and eccentricity of the axis of the bar were also evaluated, both of which significantly modify the distribution of residual stresses along the profile of the bar. It became evident that an efficient pre-straightening of the wire is important because the results of simulations show that the curvature with the drawing force and the distribution of residual stresses along the bar Cold Drawn Bars increase as well as the bar has some remnant curvature, for both dies with an angle of 15 ° and 20 °. Thus, these results demonstrate the high influence of the parameters studied distortions in the appearance of the final product.

Assim como em qualquer processo de fabricação, a qualidade do produto final deve estar aliada à otimização dos custos do processo, portanto, deve-se conhecer os fatores que alteram as propriedades do produto e que possam causar alguma influência indesejada. A trefilação de barras de aço é usualmente utilizada para conferir precisão dimensional e melhores propriedades mecânicas ao material. Um dos grandes problemas encontrados na fabricação de eixos através deste processo é o aparecimento de distorções de forma após o tratamento térmico. Tais distorções estão diretamente ligadas ao acúmulo de tensões residuais geradas durante as etapas de pré-endireitamento, jateamento e trefilação propriamente dita, modificando o comportamento e resistência mecânica, bem como a resistência à fadiga e à corrosão das peças. Portanto, este trabalho tem por objetivo analisar, através de uma abordagem numérica computacional, a influência de parâmetros de processo e propriedades do material no aparecimento de distorções em barras trefiladas de aço AISI 1045, em função de possíveis fontes geradoras de heterogeneidades, principalmente de tensões residuais durante o processo de fabricação. A análise das tensões foi realizada através da modelagem numérica 3D do processo de trefilação, sendo utilizado o software de simulação numérica computacional DeformTM. Da mesma maneira, foram analisadas as formas de agarre que fornecem a velocidade do processo, a primeira utilizando um puxador na extremidade da barra, a segunda com um puxador envolto movimentando-se ao longo da barra. Através destas análises, verificou-se que a forma de como a barra é tracionada ocasiona uma redução de até 100 MPa nas tensões residuais no centro da barra, o que representa um fator importante no estudo das possíveis causas das distorções. Observou-se ainda que os fatores de velocidade e homogeneidade da lubrificação modificaram o perfil das tensões residuais na barra. Outros parâmetros, como desalinhamento da ferramenta, diferenças de atrito, excentricidade do eixo e curvatura da barra, também foram avaliados, sendo que ambos influenciam consideravelmente na distribuição das tensões residuais ao longo do perfil da barra. Torna-se evidente a importância de um eficiente pré-endireitamento do fio máquina, pois os resultados das simulações com curvatura mostram que a força de trefilação e a distribuição das tensões residuais ao longo da barra trefilada aumentam, bem como a barra apresenta certa curvatura remanescente, para ambas as fieiras com ângulo de 15° e 20°. Sendo assim, tais resultados evidenciam a elevada influência dos parâmetros estudados no aparecimento de distorções no produto final. / As with any manufacturing process, the quality of the final product must be coupled with cost optimization of the process, so you should know the factors that alter the properties of the product that may cause some unwanted influence. The drawing of steel bars is usually used to impart better dimensional accuracy and mechanical properties to the material. One of the major problems encountered in the manufacturing of axes through this process is the appearance of distortion of size and shape after heat treatment. Such distortions are directly linked to the accumulation of residual stresses generated during the stages of pre-straightening, shot blasting and drawing itself, modifying behavior and mechanical strength, residual stresses and resistance to fatigue and corrosion of parts. Therefore, this work aims to examine, through a computational numerical approach, the influence of material parameters and process the appearance of distortions in cold drawn steel bars AISI 1045, due to possible sources of residual stresses during the manufacture. The analysis of strains and residual stresses were performed by 3D numerical modeling of the drawing process, the software being used numerical simulation computational DeformTM. In order to transmit the drawing speed, the forms of grip were analyzed using a first end of the puller bar, the second wrapped with a puller moving along the bar. Since through these analyzes, it was found that as the shape of the bar is pulled up causes a reduction in the residual stress 100 MPa in the center of the bar, which is an important factor in the study of the possible causes of the distortion. As well as factors speed and homogeneity of lubrication significantly altered the profile of residual stresses in the bar. Other parameters, such as misalignment of the tool, friction differences, curvature and eccentricity of the axis of the bar were also evaluated, both of which significantly modify the distribution of residual stresses along the profile of the bar. It became evident that an efficient pre-straightening of the wire is important because the results of simulations show that the curvature with the drawing force and the distribution of residual stresses along the bar Cold Drawn Bars increase as well as the bar has some remnant curvature, for both dies with an angle of 15 ° and 20 °. Thus, these results demonstrate the high influence of the parameters studied distortions in the appearance of the final product.

Laser joining processes, such as brazing and welding, are a common application in industry, especially in the automotive industry. These processes are the key to lightweight and efficient design with regard to the automotive industry. There, laser brazing is used mainly for visible joints due to the superior paint adhesion and surface roughness of brazed joints compared to welds. As laser brazing is applied in the automotive industry without using any fluxes or shielding gas, this leads to a difficulty in maintaining and ensuring the quality of brazed joints.

Assim como em qualquer processo de fabricação, a qualidade do produto final deve estar aliada à otimização dos custos do processo, portanto, deve-se conhecer os fatores que alteram as propriedades do produto e que possam causar alguma influência indesejada. A trefilação de barras de aço é usualmente utilizada para conferir precisão dimensional e melhores propriedades mecânicas ao material. Um dos grandes problemas encontrados na fabricação de eixos através deste processo é o aparecimento de distorções de forma após o tratamento térmico. Tais distorções estão diretamente ligadas ao acúmulo de tensões residuais geradas durante as etapas de pré-endireitamento, jateamento e trefilação propriamente dita, modificando o comportamento e resistência mecânica, bem como a resistência à fadiga e à corrosão das peças. Portanto, este trabalho tem por objetivo analisar, através de uma abordagem numérica computacional, a influência de parâmetros de processo e propriedades do material no aparecimento de distorções em barras trefiladas de aço AISI 1045, em função de possíveis fontes geradoras de heterogeneidades, principalmente de tensões residuais durante o processo de fabricação. A análise das tensões foi realizada através da modelagem numérica 3D do processo de trefilação, sendo utilizado o software de simulação numérica computacional DeformTM. Da mesma maneira, foram analisadas as formas de agarre que fornecem a velocidade do processo, a primeira utilizando um puxador na extremidade da barra, a segunda com um puxador envolto movimentando-se ao longo da barra. Através destas análises, verificou-se que a forma de como a barra é tracionada ocasiona uma redução de até 100 MPa nas tensões residuais no centro da barra, o que representa um fator importante no estudo das possíveis causas das distorções. Observou-se ainda que os fatores de velocidade e homogeneidade da lubrificação modificaram o perfil das tensões residuais na barra. Outros parâmetros, como desalinhamento da ferramenta, diferenças de atrito, excentricidade do eixo e curvatura da barra, também foram avaliados, sendo que ambos influenciam consideravelmente na distribuição das tensões residuais ao longo do perfil da barra. Torna-se evidente a importância de um eficiente pré-endireitamento do fio máquina, pois os resultados das simulações com curvatura mostram que a força de trefilação e a distribuição das tensões residuais ao longo da barra trefilada aumentam, bem como a barra apresenta certa curvatura remanescente, para ambas as fieiras com ângulo de 15° e 20°. Sendo assim, tais resultados evidenciam a elevada influência dos parâmetros estudados no aparecimento de distorções no produto final. / As with any manufacturing process, the quality of the final product must be coupled with cost optimization of the process, so you should know the factors that alter the properties of the product that may cause some unwanted influence. The drawing of steel bars is usually used to impart better dimensional accuracy and mechanical properties to the material. One of the major problems encountered in the manufacturing of axes through this process is the appearance of distortion of size and shape after heat treatment. Such distortions are directly linked to the accumulation of residual stresses generated during the stages of pre-straightening, shot blasting and drawing itself, modifying behavior and mechanical strength, residual stresses and resistance to fatigue and corrosion of parts. Therefore, this work aims to examine, through a computational numerical approach, the influence of material parameters and process the appearance of distortions in cold drawn steel bars AISI 1045, due to possible sources of residual stresses during the manufacture. The analysis of strains and residual stresses were performed by 3D numerical modeling of the drawing process, the software being used numerical simulation computational DeformTM. In order to transmit the drawing speed, the forms of grip were analyzed using a first end of the puller bar, the second wrapped with a puller moving along the bar. Since through these analyzes, it was found that as the shape of the bar is pulled up causes a reduction in the residual stress 100 MPa in the center of the bar, which is an important factor in the study of the possible causes of the distortion. As well as factors speed and homogeneity of lubrication significantly altered the profile of residual stresses in the bar. Other parameters, such as misalignment of the tool, friction differences, curvature and eccentricity of the axis of the bar were also evaluated, both of which significantly modify the distribution of residual stresses along the profile of the bar. It became evident that an efficient pre-straightening of the wire is important because the results of simulations show that the curvature with the drawing force and the distribution of residual stresses along the bar Cold Drawn Bars increase as well as the bar has some remnant curvature, for both dies with an angle of 15 ° and 20 °. Thus, these results demonstrate the high influence of the parameters studied distortions in the appearance of the final product.

This work has been performed at Outokumpu Stainless AB, QPE, in Degerfors where focus is on production of hot rolled tailor-made quarto plate in special stainless steel grades such as highly alloyed austenitics and duplex steel grades. After a period with low values in strength and a lot of deviations in tensile tests for the highly alloyed austenitic stainless steel, 254 SMO, there was a need to investigate what influence some parameters during process has on strength values. Process parameters during hot rolling and levelling have been examined to see if there is a connection between these and the strength. A statistical data base has been created to investigate the connection with strength. There has been experimental work involving two test plates in different dimensions to see how a double/extended heat treatment influence the sigma phase values and grain size, and if these can be connected to the strength values. The test plates have also been used to investigate how the position of the test coupon is affecting the tensile test result. Moreover, there have been tests performed in the cold plate leveller. The strength is a complex problem since there are many parameters that contribute to a variation in strength value. It is possible to see an influence from the investigated parameters, but their individual impact on strength varies. There are several indications in the results that the flatness seems to be a factor affecting the variation in strength. However, there is a need for more thorough investigations where the flatness can be measured to completely verify this / Det här arbetet har utförts på Outokumpu Stainless AB, QPE, i Degerfors där man inriktar sig på produktion av varmvalsad, skräddarsydd kvartoplåt i olika specialstål som höglegerade austeniter och duplexa stålsorter. Efter en period med låga värden i hållfasthet och många avvikelser i provning för ett höglegerat austenitiskt stål, 254 SMO, så fanns ett behov av att undersöka vissa parametrars inverkan på hållfastheten. Processparametrar vid valsning och riktning har undersökts för att se om det går att se ett samband mellan dessa och hållfastheten. Statistisk data har tagits fram för att undersöka sambandet med hållfastheten. Även experimentella försök har gjorts, främst på två testplåtar i olika dimensioner, för att se hur en dubbel/förlängd värmebehandling påverkar sigmafas och kornstorlek men även om dessa värden, genom försöken, kan kopplas till hållfasthetsvärden. Plåtarna har också använts till att se hur testresultatet påverkas av var i plåten som testkupongen tas ut. Dessutom har det gjorts försök i riktverket med olika parametrar. Hållfastheten är ett komplext problem att utreda eftersom det finns så många parametrar som ger en variation i resultaten. Det är möjligt att se en påverkan från flera av de undersökta parametrarna men deras individuella påverkan på hållfastheten varierar. Det finns många indikationer i resultaten som pekar på att planheten verkar vara en faktor som påverkar den variation som finns i resultat. Dock behövs det grundligare undersökningar där planheten kan mätas för att helt verifiera detta.

Abstract This thesis describes efforts made on the development of an existing catalytic incinerator. The development work, called process characterization, consists of four general parts. These are the development of measurement methodology, the studying of construction materials, the selection of suitable catalysts and the testing of the effects of process operation conditions. The two application areas for catalytic incineration considered in this thesis are solvent emission abatement (VOC, volatile organic compounds) and chip bin emission abatement (SVOC, sulphur-containing volatile organic compounds). As a baseline, the process characterization is started with the development of measurement methodology. In general, the methodology will decrease costs and simplify the carrying out of the actual measurements and thereby make the measurement time more effective. In the methodology it is proposed that continuous total concentration measurement should be used in connection with qualitative sampling to obtain reliable measurement data. The selection of suitable construction materials for the application is very important. As shown in this thesis, the end conversions in solvent emission abatement may even be improved through the selection of the proper construction materials. In chip bin emission abatement, the problem arises from corrosive oxidation products that set limits on the construction materials used as well as on oxidation conditions. Catalyst selection is based on the following catalytic properties: activity, selectivity and durability. These catalytic properties are studied either at the laboratory or on an industrial scale. The catalytic materials tested are Pt, Pd, Pt-Pd, Cu-Mn oxides, MnO2-MgO, CuxMg(1-x)Cr2O4 and CuxCr2O4. The most important selection criteria in solvent emission abatement are proposed to be activity and selectivity. In the case of chip bin-SVOC-abatement, these are selectivity and durability. Based on these criteria, catalysts containing Cu-Mn oxides and Pt were demonstrated to be the best catalysts in VOC oxidation, and catalyst containing MnO2-MgO was shown to be best catalyst in SVOC oxidation. A study on the effect of process operation parameters (temperature, concentration and gas hourly space velocity (GHSV)) and moisture was carried out with the aid of factorial design. In VOC (n-butyl acetate) oxidation, the most influential process parameter was GHSV, which decreased the end conversion when it was increased. In SVOC (DMDS) oxidation, the effect of temperature was most significant. The end conversions increased as the temperature increased. Moisture slightly decreased the formation of by-products in n-butyl acetate oxidation. In DMDS oxidation, moisture slightly increased the end conversions at a lower temperature level (300°C). At the end of the thesis, these process parameters are also discussed from the standpoint of the catalysts' activity, selectivity and durability. Finally, proposals for process improvements are suggested.

Orientador: Maria Angela de Almeida Meireles / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-26T11:16:03Z (GMT). No. of bitstreams: 1 Moraes_MoysesNavesde_D.pdf: 11795880 bytes, checksum: 816fd6cdb3996f8cf9ea868d729c0050 (MD5) Previous issue date: 2015 / Resumo: A busca por produtos naturais que apresentem elevado grau de pureza tem impulsionado pesquisas por processos de extração e, preferencialmente, que não agridam o meio ambiente. Assim, processos de extração com fluido supercrítico (SFE ¿ Supercritical Fluid Extraction) vêm ganhando espaço por propiciar extratos diferenciados. O resíduo obtido da SFE é a matriz sólida livre do extrato de interesse, sendo que esse resíduo pode ser utilizado como matéria-prima em outros processos. Atualmente há grande interesse também em processos que utilizem integralmente a matéria-prima, minimizando a produção de resíduo, e garantindo uma produção mais diversificada oriunda de uma mesma matéria-prima, mas não se pode desconsiderar o processo industrial, e para isso, é necessário desenvolver processos que possam ser integrados sem perder a continuidade da produção, mesmo que o processo, por definição, seja intitulado pseudocontínuo. Para a implementação da SFE em escala industrial uma opção é a operação pseudocontínua de extração com CO2 supercrítico (ScCO2), para que isso seja possível é necessário que a unidade de extração possua no mínimo n+1 extratores, tal que n seja um número inteiro positivo. Então, neste trabalho foi estudada a obtenção de dois tipos de extratos em operação pseudocontínua: (1) óleo volátil de cravo-da-índia, para a validação do processo de extração em modo pseudocontínuo e (2) extrato rico em tocotrienóis de sementes de urucum. Nos dois casos as matrizes vegetais após a SFE podem ser utilizadas para obtenção de outros produtos. No caso do urucum, as sementes desengorduradas possuem grande quantidade de bixina, a qual tem grande aceitabilidade no mercado devido ao seu poder corante, e por isso, utilizou-se esse resíduo como matéria-prima para a obtenção de bixina, promovendo, uma integração de processo. Ademais, o resíduo da extração da bixina e o material lignocelulósico obtido após a SFE do cravo-da-índia podem ser hidrolisados a alta pressão catalisada ou não por CO2 para produzir biopolímeros úteis para serem utilizados na fabricação de nanoestruturas porosas. Para que o processo pseudocontínuo pudesse ser desenvolvido foi necessário o conhecimento atual da área supercrítica, principalmente a nível regional (América Latina e Brasil), além da necessidade de entender as limitações que as diferentes técnicas de extração apresentam para as diferentes classes de compostos de interesse. Então o processo de extração pseudocontínuo foi avaliado, e se mostrou eficaz, permitindo aproveitamento do tempo, pois durante o período de carga e descarga de um leito extrativo o outro estava em período de extração. Deste modo, houve a manutenção de ao menos um extrator em período de extração, caracterizando-se assim a operação pseudocontínua. A extração pseudocontínua do óleo de cravo-da-índia apresentou uma taxa média 3,6 vezes maior que o processo em batelada. A manutenção da razão S/F e do tempo de extração iguais pode ser usada satisfatoriamente para mudança de escala para o cravo e o urucum, ao se utilizar extratores de relação Hb/Db distintas. Por fim, a composição química do óleo de cravo-da-índia foi distinta, sendo então aconselhado uma avaliação prévia dessa composição química antes de definir qual a relação Hb/Db será utilizada / Abstract: The demand for natural products with high purity is promoting studies focused on extraction processes that avoid environmental damages. Supercritical fluid extraction (SFE) processes are gaining emphasis because they afford the extraction of selective compounds when compared with conventional techniques. The residue from SFE is the solid matrix free of target compounds; this residue can be a raw material in other processes. Recently, the appeal for green technologies and the searching for integral use of raw materials are receiving attention. These green technologies minimize the residue generation and promote a diversified production of bioactive compounds from the same raw material. Regarding the industrial scale, integrated processes with continuous productive lines are needed, even that in some cases the processes are named pseudo continuous. Thus, the pseudo continuous extraction using supercritical CO2 (ScCO2) is an important issue for implementing SFE processes in industrial scales. To make it possible, the extraction equipment needs to contain at least n+1 extractors, where n should be a positive integer number. Based on these aspects, we performed in this study the pseudo continuous extraction of two classes of compounds: (1) volatile oil from clove buds for validating the process and (2) tocotrienol rich-extracts from annatto seeds. In both cases the material from SFE can be used to obtain other products. Defatted annatto seeds contain bixin, a coloring pigment that finds several applications. Then, we selected annatto to obtain bixin by using process integration. Furthermore, the residue from the extraction of bixin and the lignocellulosic fraction from the extraction of clove compounds can be hydrolyzed applying high pressure. The reaction can be catalyzed with CO2 to produce biopolymers useful for manufacturing porous nanostructures. To become the pseudo continuous process feasible, we evaluated the information available on the scientific community, especially in Latin America and Brazil. With this search, we could find some limitations about extracting different classes of compounds. Then, we performed the proposed operation, and it yielded good results with respect to optimizing the time. While one bed was in extraction step, the other was in charge/discharge step, characterizing the pseudo continuous extraction mode. In this case, at least one bed was maintained in extraction step along the time. The pseudo continuous extraction of clove oil presented an extraction rate 3.6-fold higher when compared with batch extraction. Besides, process scale up using the studied raw materials might be accomplished by maintaining the S/F ratio equal (for a fixed time) in different Hb/Db ratios. Finally, we observed significant difference (5 % of probability) in the chemical composition of clove oil obtained in both extractors. An evaluation of the oil composition is needed to define the suitable Hb/Db ratio for extraction processes / Doutorado / Engenharia de Alimentos / Doutor em Engenharia de Alimentos

Additive Manufacturing (AM), commonly known as 3D printing is a production method that utilises repeated addition of layers in order to produce a final shape. AM utilises less raw material and does not have drawbacks such as tool wear and material wastage as seen in conventional machining. However, they do have drawbacks such as poor surface and internal defects.  A common practice in AM is the fabrication of contour and bulk region using separate parameters.  The aim of this project was to study the effects of various process parameters on the contour properties. The process parameters considered were scanning speed, beam current and focus offset. The Nickel alloy Inconel 718 was utilised in Electron Beam Melting (EBM) to fabricate the test specimen. The samples used in this project were in an as-built condition which was priorly subjected to tensile testing for a different project. The tests performed in this project are hardness testing and microstructural investigation about grains, precipitates and the various defects.  The test results helped to understand the effect of various process parameters on the hardness and microstructure of the samples. The samples with lower scanning speed had higher hardness and lesser lack of fusion than samples with higher speed. In the case of varying beam current, the samples with higher beam current had higher hardness values and fewer lack of fusions. Similarly, the effects of varying two or more process parameters were also studied and their findings recorded. The microstructure consisted of a large number of shrinkage porosities in the bulk and contour regions. The presence of Niobium rich precipitates at grain boundaries and the grain structure for various process parameters were identified and recorded.

Method selective laser melting can produce metal parts by using 3D printing. This diploma thesis deals with the influence of process parameters on the workability of AlSi9Cu3 high-strength aluminum alloy using selective laser melting. The theoretical part deals with relations between process parameters and identifies phenomena occurring during the processing of metals by this technology. It also deals with conventionally manufactured aluminum alloy AlSi9Cu3. In the work, material research is performed from single tracks tests, porosity tests with different process parameters and mechanical testing. Here are showing the trends of porosity change at scanning speed, laser power, individual laser stop distance, bulk energy, and powder quality. The workability of the material can be judged by the degree of relative density achieved. Simultaneously the values of the achieved mechanical properties of the selected process parameters are presented. The data obtained are analyzed and compared with literature.