Orientador: Maria Angela de Almeida Meireles / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-12T20:43:53Z (GMT). No. of bitstreams: 1 Prado_IvorMartindo_M.pdf: 4325447 bytes, checksum: 55d908ce9e06c61099119b0e52a49ba1 (MD5) Previous issue date: 2009 / Resumo: O presente trabalho teve por objetivo validar um modelo do processo supercrítico aplicado a avaliação econômica utilizando-se um simulador comercial de processos (SuperPro Designer®) a partir de dados obtidos na literatura para a cúrcuma (Curcuma longa L.) e dados laboratoriais obtidos para o alecrim-pimenta (Lippia sidoides) e estudar os efeitos de aumento de escala no custo de manufatura (COM) do extrato vegetal de planta condimentar obtido por tecnologia supercrítica em equipamentos de extração supercrítica de diferentes capacidades. A validação do modelo de extrator SFE foi realizada utilizando-se o simulador de processos SuperPro Designer® que consiste de um conjunto de ferramentas capaz de estimar parâmetros econômicos e de processos, provido de um amplo banco de dados contendo substâncias simples e compostas comumente encontradas nas indústrias de alimento, química e farmacêutica. A montagem do modelo ocorreu utilizando os equipamentos disponíveis no banco de dados do simulador, porém por se tratar de um processo não convencional de extração o simulador não compreende um modelo de extrator SFE, sendo necessário adaptar esta operação unitária a um equipamento disponível, apto a realizar as funções necessárias. O aumento de escala foi avaliado utilizando-se o modelo SFE proposto que permitiu utilizar as ferramentas de aumento de escala disponíveis no simulador SuperPro Designer®. Nesta etapa assumiu-se que a relação entre a massa de solvente e a massa de alimentação permanece constante quando o modelo passa da escala laboratorial para a escala industrial, sendo assim, a relação entre rendimento e tempo de processo será igual para ambos os casos. Os fluxograma das plantas SFE estudadas no aumento de escala foram unidades semi-contínuas contendo dois extratores variando suas capacidades de 0,005 m3 a 1 m3. Os custos dos equipamentos utilizados na estimativa de custo foram comparados os preços praticados no mercado americano e chinês. Para a estimativa do custo de manufatura (COM) do processo SFE pelo simulador foram utilizados os modelos da etapa de avaliação do aumento de escala e a curva global de extração (OEC) para a cúrcuma obtida da literatura. Os tempos de ciclos do processo foram selecionados de acordo com o menor valor de estimativa do custo de manufatura segundo a avaliação da curva global de extração (OEC), no caso da cúrcuma o tempo utilizado foi de 37 minutos enquanto que no caso do alecrim-pimenta o tempo utilizado foi de 100 minutos por ciclo. Verificou-se que quando se trabalha com equipamentos de grande capacidade de produção o custo de manufatura não apresenta diferenças significativas independentemente do custo da unidade SFE, ou seja, o custo de equipamentos americanos ou chineses. Isto ocorre devido à grande participação do custo de matériaprima (CRM) no COM, enquanto que os custos de investimento (FCI) não apresentaram grande influência no custo final de manufatura / Abstract: Using the commercial simulator SuperPro Designer® the present work had for objective of validate a process model of supercritical solvent extraction (SFE) using data from literature for turmeric (Curcuma longa L.) and studying the effect of scale-up in the cost of manufacture (COM) in vegetal extract obtain via supercritical fluid extraction. The validation of the supercritical fluid extractor (SFE) was carried out using the process simulator SuperPro Designer® that consist in a set of tools capable to estimate economic parameters of processes; the simulator contains a large data base with simple substances and complex mixtures found in food chemistry and drug industries. The assembly of the model occurred using the available equipments in the data base of the simulator, however since we are dealing with a non conventional extraction process, the SFE equipment was not available in the simulator, and thus, it was necessary to develop the extraction unit before caring out the simulations. The scale-up was evaluated using the proposed model SFE that allowed the use of the available tools for scale up of the simulator SuperPro Designer®. In this stage it was assumed that the ratio between the mass of solvent and the feed mass remains constant for the laboratorial scale and the industrial scale units, therefore, the ratio between yield and process time will be equal in both cases. The flow diagram of the SFE units contains two extractors with capacities varying from 0,005 m3 to 1 m3. The costs of the SFE units were taken from manufactures in USA and China. To estimate the cost of manufacturing (COM) for the extract produced by the SFE process data for the overall extraction curve (OEC) from literature for turmeric was used. The cycles of process used in the estimate of cost had been chosen in accordance with the times that had presented lowest cost evaluated along of the overall curve of extraction (OEC), in the case of turmeric the process time used was 37 minutes whereas in the case of the alecrim-pimenta the time was used 100 minutes per cycle. It was verified that for equipment of larger capacity of production the cost of manufacturing (COM) is not significantly affected by the cost of the SFE unit (American and Chinese). This occurs due the fact that the cost of the raw material cost (CRM) predominates in the COM, while of the fixed costs of investment (FCI) represents a smaller fraction of the final COM / Mestrado / Mestre em Engenharia de Alimentos

Este trabalho estudou a aplicação de oito métodos clássicos de escalonamento de tanques condicionadores, testando sua validade para dois tanques de geometria semelhante, mas com diferentes volumes (V1=10 e V2=49 decímetros cúbicos). No interior dos tanques, operavam impulsores (diâmetro D1=0,078m x D2=0,132m) que exibiam três distintos desenhos (2 pás versus 4 pás inclinadas em 45 graus versus turbina de Rushton). Sua rotação (N1 no tanque menor x N2 no tanque maior) visava à suspensão de partículas grossas de apatita (diâmetro médio = 254 micrometros) em polpas com 40% de sólidos em massa. Para balizar o escalonamento, adotou-se como variável de controle a mínima rotação do impulsor (Njs) que é capaz de fazer com que nenhuma partícula repouse no fundo do tanque por mais do que 1 ou 2 segundos (Critério 1-s), além de perfis axiais de distribuição de sólidos e a extensão da Zona Turbulenta versus Zona Quiescente no interior dos tanques. A diferença entre o valor previsto de Njs para o tanque de 49 decímetros cúbicos (N2) pelos métodos de escalonamento versus o valor de Njs (N2) determinado experimentalmente foi expressa como erro percentual (E). Consideraram-se como adequados para a aplicação que constitui o objetivo desta dissertação todos os métodos que exibiram E menor que 10%. Para o impelidor de 2 pás inclinadas, a adequação do método baseado na constância da razão potência/volume (E=2%) e também do método empírico de Rautzen (E=6%), indica a expressão N2=N1.(D1/D2) com seu expoente da relação entre os diâmetros variando entre 0,67 e 0,75 para a aplicação desejada. Considerando o impulsor de 4 pás inclinadas, a adequação do método da constância da razão potência/volume (E=4%); assim como dos métodos empíricos de Rautzen (E=0%) e Zwietering (5%), sugere o uso da expressão N2=N1.(D1/D2) com seu expoente da relação entre os diâmetros variando entre 0,67 e 0,85. Para a turbina de Rushton, o único método que exibiu E menor que 10% foi o da constância da relação potência/volume (E=8%), cuja expressão é N2=N1.(D1/D2) com seu expoente da relação entre os diâmetros igual a 0,67. Uma vez que a determinação do valor real de N2 foi baseada numa técnica experimental influenciada pelas limitações do observador, pode-se inferir que uma expressão geral de escalonamento do tipo N2=N1.(D1/D2) com seu expoente da relação entre os diâmetros igual a 0,75 atende aos propósitos desta aplicação. Por outro lado, o uso da relação P/V provê um critério mais objetivo para se balizar o escalonamento, haja vista que ele se adequou a todos os três tipos de impelidores contemplados por este estudo. / This work has studied the application of eight classical methods appointed by literature to accomplish the scale-up of stirred tanks which aimed to suspend slurries of 40% of solids, containing coarse (mean diameter=254 micrometers) apatite particles. The validity of the methods was accomplished by using two tanks of similar geometry but different capacity (V1=10 e V2=49 cubic decimeter), together with impellers of different diameter (D1=0,078m versus D2=0,132m) and design (turbine of 2 or 4 blades inclined at 45 degrees and Rushton turbine). To assist the process of validation, the impeller speed (Njs) under which no particle rests on the bottom of the tank for more than 1-2 seconds (1-s Criterium) was used together with the axial profile of solids percent distribution plus the extension of the turbulent versus quiescent zones within the two tanks. For any of the eight scale-up methods, the difference between the predicted value of Njs (N2) for the 49 cubic decimeter tank and the actual value (experimental) of the same variable was determined and its magnitude was expressed in terms of the percent error (E). The methods that yielded E less than 10% were considered as suitable for the aimed application. Considering the 2-inclined blade impeller, low value of E yielded by the method based on the constancy of the ratio power/volume (E=2%) and also by the empiric method of Rautzen (E=6%) indicate that the expression N2=N1.(D1/D2) with its exponent of the relation between diameters ranging between 0,67 and 0,75 is suitable for the desired application. Regarding the 4-inclined blade impeller, because the method based on the constancy of the ratio power/volume (E=4%) and also the empiric methods of Rautzen (E=0%) and Zwietering (E=5%) yielded the lowest values of E, the expression N2=N1.(D1/D2) with its exponent of the relation between diameters ranging between 0,67 and 0,85 is suitable for the aimed application. Moreover, for the Rusthon turbine, only the method based on the constancy of the ratio power/volume (E=8%) was adequate for the aimed application and, thus, the expression N2=N1.(D1/D2) with its exponent of the relation between the diameters equal to 0,67 is suitable for the purpose of this dissertation. Once the actual value of N2 is determined by visual observation, it is not possible to get very accurate results. This way, a generic scale-up expression is proposed: N2=N1.(D1/D2) with its exponent of the relation between the diameters equal to 0,75. On the other hand, the ratio P/V may provide a more objective criterium for scale-up, because the three sort of impellers used in this study yielded E less than 10% when the power/volume method was applied for the purpose of scale-up.

Résumé confidentiel / Résumé confidentiel

Slot-rectangular spouted beds, with rectangular cross-section and slotted gas inlets, have been proposed as a solution to overcoming scale-up difficulties with conventional axisymmetric spouted beds. They can be utilized in gas/particle processes such as drying of coarse particles and coating of tablets. However, application of this spouted bed was limited because of instability and insufficient hydrodynamic studies. The present work is therefore aimed at the study of hydrodynamics, stability and scale-up of slot-rectangular spouted beds. The hydrodynamic study was carried out in four slot-rectangular columns of various width-to-thickness ratios combined with various slot configurations, particles of different properties and a range of operating conditions. Hydrodynamics of slot-rectangular spouted beds showed major similarity with conventional spouted beds. However, equations and mechanistic models adopted from conventional axisymmetric spouted beds generally failed to provide good predictions for the three-dimensional slot-rectangular geometry. New empirical correlations were derived for the minimum spouting velocity and maximum pressure drop for different slot configurations. Slot-rectangular spouted beds also showed more flow regimes than conventional spouted beds. Nine flow regimes, as well as unstable conditions, were identified based on frequency and statistical analysis of pressure fluctuations. Slot geometrical configuration was found to be the main factor affecting the stability of slot-rectangular spouted beds. A comprehensive hydrodynamic study on the effect of slot configuration was therefore carried out. Slots of smaller length-to-width ratio, smaller length and greater depth were found to provide greater stability. Stable criteria for the slot configuration were found consistent with the conventional axisymmetric spouted beds with extra limitation on slot length-to-width ratio and slot depth. Local distributions of pressure, particle velocity and voidage, as well as spout shape and particle circulating flux, were compared for different slot configurations. Higher slot length-to-width ratios lead to slightly higher particle circulation rates. A previously proposed scale-up method involving multiple chambers was tested in the present work using multiple slots. Instability caused by the merging of multiple spouts and asymmetric flow was successfully prevented by suspending vertical partitions between the fountains. Some criteria and guidelines were also proposed for scale-up using multiple chambers. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

The Student-Centered Active Learning Environment for Undergraduate Programs (SCALE-UP) method incorporates active learning pedagogies into space designed to facilitate effective active learning. Methods predominately used to demonstrate the effectiveness of active learning in STEM fields do not generally account for differences in student characteristics; furthermore, there is a lack of data sources that measure student-centered educational practices. This study examined the impact of SCALE-UP on student achievement in introductory biology, as evidenced by course grades. A regression framework was used to account for student characteristics. Course syllabi, classroom observation data, and an instructor interview were examined to gain deeper understanding of teaching practices across classes being compared. Findings indicate the SCALE-UP classroom did not directly impact biology course grades; however, it did impact the nature of active learning techniques used during the course. Implications for practice and future research were discussed.

Graph-structured data can be found in nearly every aspect of today's world, be it road networks, social networks or the internet itself. From a processing perspective, finding comprehensive patterns in graph-structured data is a core processing primitive in a variety of applications, such as fraud detection, biological engineering or social graph analytics. On the hardware side, multiprocessor systems, that consist of multiple processors in a single scale-up server, are the next important wave on top of multi-core systems. In particular, symmetric multiprocessor systems (SMP) are characterized by the fact, that each processor has the same architecture, e.g. every processor is a multi-core and all multiprocessors share a common and huge main memory space. Moreover, large SMPs will feature a non-uniform memory access (NUMA), whose impact on the design of efficient data processing concepts should not be neglected. The efficient usage of SMP systems, that still increase in size, is an interesting and ongoing research topic. Current state-of-the-art architectural design principles provide different and in parts disjunct suggestions on which data should be partitioned and or how intra-process communication should be realized. In this thesis, we propose a new synthesis of four of the most well-known principles Shared Everything, Partition Serial Execution, Data Oriented Architecture and Delegation, to create the NORAD architecture, which stands for NUMA-aware DORA with Delegation. We built our research prototype called NeMeSys on top of the NORAD architecture to fully exploit the provided hardware capacities of SMPs for graph pattern matching. Being an in-memory engine, NeMeSys allows for online data ingestion as well as online query generation and processing through a terminal based user interface. Storing a graph on a NUMA system inherently requires data partitioning to cope with the mentioned NUMA effect. Hence, we need to dissect the graph into a disjunct set of partitions, which can then be stored on the individual memory domains. This thesis analyzes the capabilites of the NORAD architecture, to perform scalable graph pattern matching on SMP systems. To increase the systems performance, we further develop, integrate and evaluate suitable optimization techniques. That is, we investigate the influence of the inherent data partitioning, the interplay of messaging with and without sufficient locality information and the actual partition placement on any NUMA socket in the system. To underline the applicability of our approach, we evaluate NeMeSys against synthetic datasets and perform an end-to-end evaluation of the whole system stack on the real world knowledge graph of Wikidata.

The future of fuels will most probably be a mixture of different fuels, called drop-in fuels. It is already known that these drop-in fuels will lead to solubility issues, with creation of deposit on crucial fuel system parts, due to the formation of soft particles. The fuel system of the future should be robust against any type of soft particles. Today, there is no scaled up test fluid existing for testing full scale fuel systems. The objective of this thesis was to develop a scaled up test fluid which is a key element to the development of a test method to enhance the fuel system robustness against soft particles. A test fluid was achieved by a concentrate of calcium soap diluted two thousand times to reach a volume of 1000 litres with a concentration of 1,4 ppm. The concentration was measured by gas chromatography mass spectroscopy method following a derivatisation as sample preparation. The formation of the concentrate was established by changing the type of fuel, the level of aging, the amount of calcium and other counterions and eventually by addition of third elements. The concentrate was made of aged B100, calcium oxide powder and water. The test fluid was made by diluting the concentrate with fresh B7 and a protocol to characterise the stability of this test fluid was developed. This test fluid was tested under real condition in a filter rig giving homogeneous concentration all along the experiment, which confirmed the stability of the test fluid.

The objective of this study was to evaluate the effect of two pedagogical models used in general education science on non-majors' science teaching self-efficacy. Science teaching self-efficacy can be influenced by inquiry and cooperative learning, through cognitive mechanisms described by Bandura (1997). The Student Centered Activities for Large Enrollment Undergraduate Programs (SCALE-UP) model of inquiry and cooperative learning incorporates cooperative learning and inquiry-guided learning in large enrollment combined lecture-laboratory classes (Oliver-Hoyo & Beichner, 2004). SCALE-UP was adopted by a small but rapidly growing public university in the southeastern United States in three undergraduate, general education science courses for non-science majors in the Fall 2006 and Spring 2007 semesters. Students in these courses were compared with students in three other general education science courses for non-science majors taught with the standard teaching model at the host university. The standard model combines lecture and laboratory in the same course, with smaller enrollments and utilizes cooperative learning. Science teaching self-efficacy was measured using the Science Teaching Efficacy Belief Instrument - B (STEBI-B; Bleicher, 2004). A science teaching self-efficacy score was computed from the Personal Science Teaching Efficacy (PTSE) factor of the instrument. Using non-parametric statistics, no significant difference was found between teaching models, between genders, within models, among instructors, or among courses. The number of previous science courses was significantly correlated with PTSE score. Student responses to open-ended questions indicated that students felt the larger enrollment in the SCALE-UP room reduced individual teacher attention but that the large round SCALE-UP tables promoted group interaction. Students responded positively to cooperative and hands-on activities, and would encourage inclusion of more such activities in all of the courses. The large enrollment SCALE-UP model as implemented at the host university did not increase science teaching self-efficacy of non-science majors, as hypothesized. This was likely due to limited modification of standard cooperative activities according to the inquiry-guided SCALE-UP model. It was also found that larger SCALE-UP enrollments did not decrease science teaching self-efficacy when standard cooperative activities were used in the larger class.

Polymer extrusion is an energy intensive process whereby the simultaneous action of viscous shear and thermal conduction are used to convert solid polymer to a melt which can be formed into a shape. To optimise efficiency, a homogeneous melt is required with minimum consumption of process energy. In this work, in-process monitoring techniques have been used to characterise the thermal dynamics of the single screw extrusion process with real-time quantification of energy consumption. Thermocouple grid sensors were used to measure radial melt temperatures across the melt flow at the entrance to the extruder die. Moreover, an infrared sensor flush mounted at the end of the extruder barrel was used to measure non-invasive melt temperature profiles across the width of the screw channel in the metering section of the extruder screw. Both techniques were found to provide useful information concerning the thermal dynamics of the extrusion process; in particular this application of infrared thermometry could prove useful for industrial extrusion process monitoring applications. Extruder screw geometry and extrusion variables should ideally be tailored to suit the properties of individual polymers but in practise this is rarely achieved due the lack of understanding. Here, LDPE, LLDPE, three grades of HDPE, PS, PP and PET were extruded using three geometries of extruder screws at several set temperatures and screw rotation speeds. Extrusion data showed that polymer rheology had a significant effect on the thermal efficiency on the extrusion process. In particular, melt viscosity was found to have a significant effect on specific energy consumption and thermal homogeneity of the melt. Extruder screw geometry, set extrusion temperature and screw rotation speed were also found to have a direct effect on energy consumption and melt consistency. Single flighted extruder screws exhibited poorer temperature homogeneity and larger fluctuations than a barrier flighted screw with a spiral mixer. These results highlighted the importance of careful selection of processing conditions and extruder screw geometry on melt homogeneity and process efficiency. Extruder scale was found to have a significant influence on thermal characteristics due to changes in surface area of the screw, barrel and heaters which consequently affect the effectiveness of the melting process and extrusion process energy demand. In this thesis, the thermal and energy characteristics of two single screw extruders were compared to examine the effect of extruder scale and processing conditions on measured melt temperature and energy consumption. Extrusion thermal dynamics were shown to be highly dependent upon extruder scale whilst specific energy consumption compared more favourably, enabling prediction of a process window from lab to industrial scale within which energy efficiency can be optimised. Overall, this detailed experimental study has helped to improve understanding of the single screw extrusion process, in terms of thermal stability and energy consumption. It is hoped that the findings will allow those working in this field to make more informed decisions regarding set conditions, screw geometry and extruder scale, in order to improve the efficiency of the extrusion process. / Engineering and Physical Sciences Research Council

L'optimisation d'une opération de mélange de poudre repose essentiellement sur un travail expérimental à l'échelle du laboratoire qui doit pouvoir être transposer aux mélangeurs de plus grandes tailles. Définir des lois d'extrapolation et améliorer notre connaissance de la dynamique du mélange est donc nécessaire. Dans ces travaux, la dynamique de mélange au sein des mélangeurs Turbula® a été étudiée en s'appuyant sur l'analyse des cinétiques de mélange et des fonctions d'autocorrélation pour plusieurs systèmes particulaires. Selon les vitesses de rotation de l'axe moteur, 3 régimes d'écoulement ont été définis et les principaux mécanismes de mélange et de ségrégation apparaissant pour chacun de ces régimes ont été identifiés en lien avec les propriétés d'écoulement des produits. Dans un deuxième temps, les qualités de mélange obtenues dans différentes tailles de mélangeurs ont été comparées sur la base du principe des similitudes afin de mettre en évidence les facteurs ayant une influence lors du passage d'une taille de mélangeur à une autre. Enfin dans le cadre d'une application industrielle, une méthodologie s'appuyant sur l'intensité de ségrégation et l'autocorrélation spatiale, a été développée pour identifier des défauts d'homogénéité au sein de plaques bipolaires composites / The optimization of a powder mixing step typically involves an experimental work at lab scale in order to be transposed to larger mixers. Defining scale-up laws and improving our knowledge of the mixing dynamics remains some of the mains industrial issues of this century. In this work, the mixing dynamics of several particulate systems has been studied in Turbula mixers thanks to the analysis of mixing kinetics and autocorrelation functions. According to the engine speed, three flow regimes have been defined. The corresponding main mixing and segregation mechanisms at play for each of these regimes have been identified in relation with the flow properties of the products. In a second phase, the qualities of the mixtures obtained in the different mixer sizes have been compared on the basis of the principle of similarities in order to shed light the factors which influencing scale-up. Finally, as part of an industrial application, a methodology has been developed using the concept of intensity of segregation and the spatial autocorrelation tools to identify heterogeneities in bipolar plates made of composite materials