Thesis (MEng)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Long-chain hydrocarbons are of value to numerous lucrative industries. Due to the low volatility and close melting and boiling points of these solutes, traditional fractionation methods lack the required selectivity for separation and cause thermal degradation of the product. This project investigates the feasibility of Supercritical Fluid Extraction (SFE) for processing these systems, with the primary objective of modelling the high-pressure vapour-liquid equilibrium (VLE) properties of hydrocarbon solutes with a light-weight solvent using a semiempirical equation of state (EOS). Pure component vapour pressures and saturated liquid volumes are also investigated. A thorough investigation into the phase behaviour of the n-alkanes, 1-alcohols, carboxylic acids and esters in light weight supercritical solvents CO2, ethane and propane revealed that the solute structure and temperature largely influence the solute solubility and process feasibility. Good selectivity amongst the various solutes was observed for all three solvents, but very high pressures were required for complete miscibility using CO2 (exceeding 30 MPa). The quadrapole moment of CO2 further leads to complexities in phase behaviour such as temperature and density inversions (CO2/alkanes and CO2/alcohols) and 3-phase regions within the operating range. Simple linear trends in pressure vs. carbon number and temperature were observed for all the considered series using ethane and propane and these solvents were thus selected for conducting the modelling for this study. A thorough review of semi-emperical EOS models from literature revealed that the simple cubic equations of state (CEOSs) provide a promising modelling approach for SFE applications due to their simplicity, flexibility and reliability. The simple Peng-Robinson (PR) and Soave-Redlich-Kwong (SRK) EOSs provide good correlation of vapour pressure (%AAD below 5 %) for all the series over a large carbon number range (up to nC20), provided a two parameter alpha function is used. A 3rd parameter in the volume dependence for Patel-Teja (PT) EOS provides considerable improvement over the PR and SRK EOSs for satureate liquid volume correlations of the non-polar solutes (alkanes and esters), but offers virtually no advantage for the more polar alcohols and acids. The CEOSs therefore suffer clear limitations in simultaneous representation of these saturation properties (vapour pressure and liquid molar volume) for the systems of interest. Good correlations of high pressure binary VLE data were obtained using CEOSs available in the Aspen Plus ® simulator (% AAD in P, T and X2 generally below 1 % and ranging from 4 to 12 % for Y2 for all series) provided that two binary interaction parameters (BIPs) are used in the model mixing rules, irrespective of the model used. Aspen Plus ® was further validated as a reliable thermodynamic tool by comparing model fits using the RK-ASPEN model with parameters obtained from the Aspen Plus ® data regression routine and computational methods used in self-developed MATLAB software. Very similar results were obtained for both computational methods, which encourages the use of Aspen Plus ® for process modelling in SFE applications. A statistical sensitivity analysis into the relative effect and interactions between 6 modelling factors in applying the CEOSs revealed that the mixing rules, temperature and solute structure had the largest effect on the correlation of the high pressure VLE, with the pure component limit having negligible effect once BIPs are fitted to data. A significant interaction was, however, observed between the pure component model and the solute structure and temperature, which suggest that accurate correlation of mixture VLE does not solely rely on appropriate mixing rule selection, but also the pure model. Binary interaction parameters (BIPs) in model mixing rules were found to become intercorrelated when more than one are used, greatly impeding the development of generalized correlations. BIPs were also found to be sensitive to the pure component limit (alpha function and pure constants used), the temperature, the combining rules used and possibly the fluid density. These factors should all be taken into account systematically for developing generalized correlations which therefore fell outside the scope of this study. Recommendations were, however, made on how the MATLAB software developed in this study can be used to both expand the size of the statistical analysis already conducted into relevant modelling factors and to develop new generalized correlations for BIPs and new mixing rules. / AFRIKAANSE OPSOMMING: Lang-ketting koolwaterstowwe is van waarde in talle winsgewende industriële toepassings. Vanweë die lae vlugbaarheiden ooreenstemmende kook- en smeltpunte van hierdie molekules, toon tradisionele fraktioneringsmetodes nie die nodige selektiwiteit vir ekstraksie nie en veroorsaak bonop termiese degradering van die produk. Hierdie projek ondersoek dus die lewensvatbaarheid van superkritiese ekstraksie vir die prosesering van hierdie sisteme, met primêre fokus op die modellering van die hoë-druk damp-vloeistof ewewig eienskappe van koolwaterstowwe opgelos in ‘n lae-massa oplosmiddel met gebruik van ‘n semi-empiriese toestandsvergelyking. Suiwer-komponent dampdrukke en versadigde vloeistof volumes word ook ondersoek. ‘n Deeglike ondersoek na die fasegedrag van die n-alkane, 1-alkohole, korboksiel-sure asook esters in lae-massa superkritiese oplosmidds CO2, etaan en propaan toon dat die struktuur van die opgeloste stof en die temperatuur ‘n groot invloed het op die oplosbaarheid en proses lewensvatbaarheid. Goeie selektiwiteit tussen die verskillende koolwaterstowwe was waargeneem vir al drie oplosmiddels, alhoewel baie hoë drukke nodig was vir totale vermenging van die fases in CO2 (hoër as 30 MPa). Die quadrupool moment van CO2 veroorsaak verder ongewenste kompleksiteite in fase gedrag soos temperatuuren digtheid inversies (CO2/alkane en CO2/alkohole) en 3-fase-gebiede in die bedryfs-kondisies. Eenvoudige lineêre tendense in druk tenoor die koolstofnommer van die opgeloste stof asook die temperatuur was waargeneem vir al die ondersoekte koolwaterstof reekse in etaan en propaan en hierdie oplosmiddels was dus gekies vir die modellering vir hierdie studie. 'n Deeglike oorsig van semi-empiriese toestandsvergelykings uit die literatuur het getoon dat die eenvoudige kubiese toestandsvergelykings ‘n belowende modelleringsbenadering bied vir superkritiese ekstraksie toepassings vanweë hul eenvoudigeid, buigsaamheid enbetroubaarheid. Die eenvoudige Peng-Robinson (PR) en Soave-Redlich-Kwong (SRK) toestandsvergelykings bied goeie korrelasie van suiwer dampdruk (foute laer as 5 %) vir alle koolwaterstowwe oor ‘n groot koolstofnommer gebied (tot by nC20), met die voorwaarde dat ‘n 2 parameter alpha funksie gebruik word. ‘n 3rde parameter in die volume afhanklikheid van die Patel-Teja (PT) toestandsvergelyking bied ‘n beduidende verbetering in die passing van die versadigde vloeistof volume vir die nie-polêre koolwaterstowwe (n-alkane en die esters), maar bied geen voordeel vir die meer polêre alkohole en karkoksiel sure nie. Die kubiese modelle toon dus duidelike beperkings vir die gelyktydige voorstelling van hierdie versadigingde eienskappe (dampdruk en vloeistof volume) vir die sisteme van belang. Goeie korrelasie van hoë druk binêre damp-vloeistof ewewig data was verkry deur gebruik van die kubiese toestandsvergelykings beskikbaar inAspen Plus ® (fout in P, T en X2 tipies laer as 1 % en van 4 tot 12 % vir Y2 vir alle sisteme), met die voorwaarde dat 2 binêre interaksie parameters gebuik word in die model mengreëls, onafhanklik van die model. Aspen Plus ® was verder bekraktig as ‘n betroubare termodinamiese hulpmiddel deur model passings te vergelyk met die RK-ASPEN model tussen gevalle waar parameters verkry is deur die beskikbare regressie metode in Aspen Plus ® en metodes gebruik in self-ontwikkelde MATLAB sagteware. Eenderse resultate was verkry vir beide berekeningsmetodes, wat die gebruik van Aspen Plus ® vir prosesmodellering in superkritiese ekstrasie toepassings aanmoedig. ‘n Satistiese sensitiwiteits analise op die relatiewe effek en interaksies tussen 6 modelleringsfaktore in die toepassing van die kubiese toestandsvergelykings het gevind dat die mengreëls, temperatuur en die stuktuur van die opgeloste stof die grootste effek op die korrelasie van hoë druk binêre damp-vloeistof ewewig het, met ‘n weglaatbare effek vandie suiwerkomponent limiet waargeneem sodra binêre interaksie parameters gepas is aan data. ‘n Beduidende interaksie was wel waargeneem tussen die suiwerkomponent model en die struktuur van die opgeloste stof asook die temperatuur, wat daarop dui dat akurate korrelasie van mengsel damp-vloeistof ewewig nie slegs afhanklink is van ‘n gepaste keuse van mengreëls nie, maar ook die suiwer-komponent model. Binêre interaksie parameters in die model mengreëls ondergaan inter-korrelasie wanneer meer as een interaksie parameter gebruik word, wat die ontwikkeling van algemeen toepaslike korrelasies grotendeels belemmer. Binêre interaksie parameters was ook bevind om sensitief te wees tot die suiwer component limiet (alpha funksie en suiwer konstantes wat gebruik is), die temperatuur, die kombineringsreëls en moontlik die vloeistof digtheid. Hierdie faktore moet dus almal sistematies in ag geneem word wanneer algemeen toepaslike korrelasies ontwikkel word, wat dus buite die omvang van die huidge studie val. Aanbevelings was wel gemaak vir hoe die MATLAB sagteware ontwikkel vir hierdie studie gebruik kan word om beide die betaande statistiese analise uit te brei, asook nuwe korrelasies vir binêre interaksies parameters en nuwe mengreëls te ontwikkel.

L'implantation par les collectivités locales d'un ENT (Espace Numérique de Travail) dans les lycées et collèges n'est pas sans conséquences pour le quotidien de la communauté éducative. Notre étude s'intéresse ainsi à comprendre les usages émergents en procédant à une décomposition du processus d'appropriation. Elle répond également à une commande institutionnelle dont l'objectif politique est tourné vers l'encouragement et la stimulation des usages de ce type d'outil. Par conséquent, nous avons cherché à créer un modèle permettant de comprendre qui sont les utilisateurs de l'ENT et comment s'enclenche le passage des usages prescrits par les concepteurs aux comportements d'usages constatés sur le terrain.Pour sa concrétisation, notre modèle s'est construit sur la base d'un ensemble de travaux préalables.- L'étude du cadre de fonctionnement, à partir d'entretiens auprès des prescripteurs et de l'analyse du cahier des charges de l'ENT lorrain.- L'étude du cadre d'usage, d'une part, grâce aux mesures d'audiences de la CDC (Caisse des Dépôts et Consignation), d'autre part, par des questionnaires chargés de rendre compte des premiers usages ainsi que de la représentation sociale de l'ENT et de son cahier de textes pour les élèves, leurs enseignants et parents.Le modèle ainsi formalisé, soutenu par une littérature déjà robuste, est nommé : DAME (Dynamic Acceptance Model for Education). Il a été élaboré sur une population de 3 100 élèves, 774 parents, 617 enseignants et 44 membres du personnel de la vie scolaire.Les résultats obtenus, témoignent dans un premier temps, de l'importance à accorder aux perceptions d'« utilité » et d'« utilisabilité ». Pour favoriser l'adoption d'un l'ENT et donc son acceptabilité dans le cadre des activités quotidiennes d'enseignement, il est essentiel que sa prise en main ainsi que sa plus-value liée à son usage soit pleinement perçue. Dans un deuxième temps, il apparaît nécessaire de tenir compte des personnes qui entourent l'utilisateur, ce que nous qualifions dans notre modèle de « pression sociale », les élèves et le personnel de vie scolaire y étant particulièrement réceptifs. Dans un troisième temps, nous observons que les propriétés de l'outil peuvent engendrer ce que nous désignons par une « pression instrumentale » qui agit de manière rétroactive sur les précédentes variables. Du fait d'un usage répété, une dépendance à l'ENT peut s'installer lorsque celui-ci devient essentiel au bon déroulement de son activité, qu'elle soit professionnelle ou d'apprentissage, ce qui est notamment le cas pour les fonctionnalités : cahier de textes et espace d'informations. Néanmoins, notre modèle met également en évidence que d'autres facteurs sont susceptibles d'intervenir pour expliquer les usages, de nouvelles perspectives de recherches sont par conséquent à prévoir. Enfin, il apparaît évident, sur la base de nos différentes enquêtes, que les principaux bénéficiaires des ENT restent incontestablement les parents et les élèves. Ils manifestent tous deux de forts intérêts pour son usage mais se heurtent à la résistance de certains enseignants dénonçant une charge de travail supplémentaire et une trop grande transparence des informations qu'ils y déposent. / The implementation, by local collectivity, of a VLE (Virtual Learning Environment) in secondary schools and high school is not without consequences for the educational community daily activities. Our study aims to understand emerging uses by carry out a decomposition of the appropriation process. It also responds to an institutional command whose aim is turned toward the promotion and stimulation of the utilisation of this type of tool. Therefore, our objective is to create a model to understand which are VLE users and how is managed the transition between uses prescribed by the creators and observed behaviors.For its concretization, our model is built on a set of preliminary work.- The operating frame study based on interviews with prescribers and the analysis of the Lorraine VLE project specification chart.- The use frame study, on one hand, through uses counter measures from the CDC (Caisse des Dépôts group), on the other hand, by questionnaires upon which functions we report first uses and social representation of a VLE and his book-texts by students, teachers and parents.The model pattern, supported by a robust literature, is called: DAME (Dynamic Acceptance Model for Education). It was applied to a population of 3,100 students, 774 parents, 617 teachers and 44 staff members of school life.The results show in a first step, the importance given to "usefulness" and "usability" perceptions. To promote the adoption of a VLA, and therefore its acceptability in the daily teaching activities, it's crucial that its handling and its added value were associated with its use are fully perceived. In a second step, it seems necessary to take into account, the social network of the user, what we call in our model "social pressure", students and staff of school life being particularly responsive to it. In a third step, we observe that tool properties can generate what we designate by "instrumental pressure" which retroactively impact on previous variables. Due to repeated use, addiction to ENT may be installed when it becomes essential for the quality of his professional or learning activity, which is notably the case for two functionalities: text-book and information space. Nevertheless, our model shows that other factors can be able to explain uses; therefore, new research prospects can be expected. Finally, it seems clear, on the basis of our various surveys, that the main beneficiaries of VLE are mainly parents and students. But if both show strong interest for its use, they are confronted to the resistance of some teachers denouncing an overwork and an excessive transparency of uploaded information.

A formação dos engenheiros de produção com competências capazes de se tornarem profissionais adequados para trabalhar em equipes, resolver problemas de forma rápida e colaborativa, em redes e acompanhar as inovações tecnológicas no parque industrial e na administração das empresas, necessidades inerentes ao contexto da sociedade da informação, mostrou-se insuficiente, onde a metodologia tradicional de ensino não tem permitido, de forma adequada, a obtenção desses propósitos. O objetivo desta dissertação é propor a implementação de melhoria no desenvolvimento das competências profissionais no ensino de engenharia de produção com o auxílio de um Ambiente Virtual de Aprendizagem (AVA) - MOODLE e a metodologia PBL (Problem Based Learning). A metodologia que será utilizada é a pesquisa bibliográfica na utilização do PBL em vários cursos e também a criação de um protótipo com as duas ferramentas para a disciplina Sistema de Informação no curso de graduação de engenharia de produção, com o propósito de possibilitar a validação da proposta na continuidade do trabalho após a defesa da dissertação. / The traditional teaching method in the production engineer formation is inadequate to promote the development of their necessary competencies. The information society environment requires team working, quickly problems solving in a collaborative network, and keeping up with the technology innovation in the industrial plants and in the organizations management. This dissertation proposes an improvement of the professional competencies development in the production engineering teaching with the aid of a Virtual Learning Environment (VLE) - MOODLE and the PBL methodology (Problem Based Learning). The library searching methodology will be used when applying PBL into various courses. A prototype will also be applied with both tools in the Information System subject matter included in the production engineering graduation course. The purpose is to validate the proposal following the dissertation presentation.

Os líquidos iônicos são uma das principais apostas para revolucionar a química no século XXI. Em geral, apresentam propriedades como baixa pressão de vapor, alta estabilidade térmica, e ampla existência liquida e outras que os tornam interessantes para aplicações como solventes para extração, meio reacional e como meio catalítico. Estas propriedades permitem a redução da geração de efluentes industriais, o que os torna potenciais solventes verdes. O interesse recente aumentou a quantidade de ânions e cátions disponíveis para formar líquidos iônicos. Essa maior diversidade por um lado aumenta o potencial de aplicação industrial dos líquidos iônicos, mas por outro aumenta a carga de trabalho para obter as propriedades necessárias para projeto industrial destas novas substâncias. Métodos preditivos podem ser utilizados para evitar a grande demanda de ensaios experimentais para obter essas propriedades. Entretanto modelos puramente preditivos, como o COSMO-RS, usualmente não obtém uma acurácia adequada para o uso industrial. Modelos que fazem uso de dados experimentais de misturas para estimar seus parâmetros, como o UNIFAC (Do) e o F-SAC, são predominantes na indústria. Esses modelos, que são modelos de coeficiente de atividade, permitem o cálculo de equilíbrio de fases e outras propriedades termodinâmicas. Este trabalho teve como objetivo o desenvolvimento do modelo F-SAC para líquidos iônicos. Baseado em trabalhos anteriores, foram reestimados os parâmetros dos grupos de líquidos iônicos já existentes e adicionados novos grupos de cátions e ânions. Também foram geradas as primeiras curvas de equilíbrio líquido-vapor de misturas contendo líquidos iônicos com o F-SAC. De forma geral, para os 1-alquil-3-etil-imidazólios, foi obtido um R2 de 0.9794 e o valor de AAD de 0.1721 para 1514 misturas com o modelo F-SAC, superior ao encontrado para o UNIFAC (Do). Para o piridínio e o pirrolidínio o F-SAC obteve, respectivamente, um R2 de 0.9281 e 0.9837 e um valor de AAD de 0.2749 e 0.0962. Com este trabalho é possível formar 24 diferentes líquidos iônicos base com o uso de 33 parâmetros eletrostáticos estimados e 22 parâmetros geométricos no F-SAC. Para o mesmo objetivo o modelo UNIFAC (Do) necessitaria de 180 parâmetros binários e 26 parâmetros individuais – todos estimados. Ou seja, o F-SAC, nesse caso, precisou estimar apenas 27% do número de parâmetros que o UNIFAC (Do). / Ionic Liquids are one of the most promising fields to revolutionize chemistry in the 21st century. In general, they show properties like negligible vapor pressure, high thermal stability, wide liquid existence turn them interesting for applications as solvents for extraction, as reactional and catalytic media. These properties allow a reduction in industrial effluent production, making them eligible green solvents. Recent inteerest expanded the number of anions and cations available to compose Ionic. This great diversity enhances the industrial application potential of Ionic Liquids, while increases the workload needed for obtaining properties of these new substances needed for industrial project. Predictive methods can used to avoid the demand of experiments to obtain these properties. Purely predictive methods, as COSMO-RS, are usually not accurate enough for industrial use. Models use experimental data from mixtures for parameter estimation like UNIFAC (Do) and F-SAC, are predominant in the industry. Activity coefficient models like these allow the solving of phase equilibria and other thermodynamic properties. This work aimed at developing the F-SAC model for Ionic Liquids. Based on previous works, the already existing parameters for Ionic Liquid groups were reestimated and new cation and anion groups were added. In addition, the first vapor-liquid equilibrium curves for mixtures containing Ionic Liquids were created for the F-SAC model. For 1-alkyl-3-ethyl-imidazoliums, an overall R2 of 0.9794 and AAD of 0.1721 for 1514 mixtures was obtained, superior to UNIFAC (Do) values. For pyridinium and pyrrolidinium, F-SAC achieved, respectively, R2 of 0.9281 and 0.9837 and AAD of 0.2749 and 0.0962. With this work is possible to form 24 different base Ionic Liquids with 33 estimated electrostatic parameters and 22 geometric parameters with F-SAC. For the same purpose, UNIFAC (Do) would need 180 binary parameters and 23 individual parameters – all estimated. For this particular case the F-SAC model needed to estimate only 27% of the parameter number UNIFAC (Do) needed.

O modelo F–SAC (Functional–Segment Activity Coefficient), recentemente introduzido, combina a ideia de contribuição de grupos com a teoria de superfícies de contato COSMO–RS. Este modelo tem uma dependência reduzida dos parâmetros de interação binária quando comparado com as variantes do modelo UNIFAC e precisão melhorada quando comparada com modelos baseados em COSMO. No presente trabalho uma modificação na formulação do modelo F–SAC é proposta para a inclusão de interações dispersivas. Para testar esta modificação, foram considerados os dados experimentais de alcanos, ciclo–alcanos, alcenos, aromáticos e perfluorocarbonetos. O modelo proposto foi capaz de correlacionar entalpias de vaporização de substâncias puras, não consideradas em versões anteriores do modelo. Uma vez que a capacidade calorífica de líquidos está intimamente relacionada com a entalpia de vaporização, o modelo também pode prever a capacidade calorífica de substâncias puras. Em relação ao coeficiente de atividade em diluição infinita e dados de equilíbrio líquido–vapor, o modelo modificado manteve o bom desempenho do modelo original, também semelhante a outros modelos similares, como variantes do modelo UNIFAC. Além disso, o modelo modificado pode agora calcular valores consistentes para a entalpia e entropia de excesso para sistemas onde as interações são principalmente dispersivas. Para estes sistemas, a maioria dos modelos de coeficiente de atividade prevê entalpia de excesso zero, contrabalançando valores de energia de Gibbs de excesso confiáveis com entropias de excesso distorcidas. / The recently introduced F–SAC (Functional–Segment Activity Coefficient) model combines the group contribution idea with a COSMO–RS surface contacting theory. This model has a reduced dependency on binary interaction parameters when compared to classical UNIFAC type models and improved accuracy when compared with COSMO based models. In the present work a modified F–SAC formulation is proposed for including dispersive interactions. For testing the modification, experimental data of alkanes, cycloalkanes, alkenes aromatics and perfluorocarbons were considered. The proposed model was able to correlate pure compound enthalpies of vaporization, not considered in previous versions of the model. Since the heat capacity of liquids is closely related to the enthalpies of vaporization, the model also can predict pure compound heat capacity of liquids. Regarding mixture infinite dilution activity coefficient and vapor–liquid equilibrium data, the modified model maintained the good performance of the original model, also similar to other competing models such as UNIFAC variants. Additionally, the modified model now can compute consistent values for the excess enthalpy and entropy for systems where the interactions are mainly dispersive. For these systems, most activity coefficient models predict zero excess enthalpies, counterbalancing that with distorted excess entropies.

Modelos de atividade baseados em COSMO se apresentam como uma interessante alternativa para a predição do comportamento de substâncias em mistura. Estes modelos dependem apenas de informações das substâncias puras, como volume e área superficial e outra informação conhecida como perfil sigma, que podem ser determinados através de cálculos de química quântica computacional. O presente trabalho tem por objetivo criar e disponibilizar gratuitamente um banco de dados de perfis sigma para um vasto conjunto de moléculas utilizando o software GAMESS. Para a criação desse banco de dados com informações confiáveis de perfis sigma, foram testados diferentes níveis de teoria para o cálculo da estrutura eletrônica das moléculas, bem como conjuntos de bases distintos, considerando funções de polarização e efeitos difusos. Para realizar a validação dos perfis sigma obtidos, foram estimados valores de coeficientes de atividade em diluição infinita, obtidos através do modelo COSMO-SAC para um conjunto de 689 misturas, as quais não apresentam ligação de hidrogênio. A correlação com os valores de coeficiente de atividade em diluição infinita (IDAC) experimentais, foram construídos gráficos do logaritmo natural de IDAC experimentais e aqueles calculados pelo modelo. O tempo computacional total para obter os perfis sigma também foi avaliado com o intuito de escolher a melhor combinação de teoria e função de base. Dentre os métodos analisados, a teoria de Hartree-Fock (HF) com a função de base 6-311G(d,p) apresentou um bom custo benefício no que se refere ao tempo computacional e a precisão dos resultados frente a dados experimentais, apresentando um coeficiente de determinação superior a 0,94. A partir desses resultados, foi possível criar outros perfis sigma para um número maior de moléculas e disponibilizar essas informações em um banco de dados criado na plataforma do GitHub. / COSMO-based activity coefficient models are widely used to predict non-ideality in mixtures. They require only pure substance properties, such as the -profile, a representation of the screening charge density along the molecular surface. The present work aims to create and freely distribute a -profile database which can be easily extended by the community using the free GAMESS quantum chemistry (QC) package. Different combinations of QC methods and basis sets were tested in the calculation of the -profiles, aiming to define an efficient approach to create the database. The accuracy of COSMO-SAC predictions using these -profiles was evaluated by comparison with experimental infinite dilution activity coefficients and phase equilibrium diagrams. Among the studied alternatives, the Hartree-Fock method with the 6-311G(d,p) basis set led to results with a good balance between accuracy and computational cost. Our database was created using this approach, and it is already available to be used and extended by the community without requiring any commercial software.

Thickness shear mode (TSM) sensors, also known as quartz crystal micro-balances (QCM) are a class of acoustic wave sensors that have been used for gas phase sensing. In this thesis this device is used to measure vapor-liquid equilibrium data for copolymers of poly(styrene-butadiene) at 294K. Copolymers of poly(styrene-butadiene) with varying percentages of styrene (85%, 45% and 21 %) were studied with benzene, n-hexane, dichloroethane and chloroform as solvents. Literature data for pure polystyrene/benzene and polystyrene/chloroform and polybutadiene/benzene were obtained to complement the measured data. Obtained experimental data were fit with a modified Flory-Huggins model and compared with the predictions of three models (UNIFAC-FV, Entropic-FV, and GK-FV). Flory-Huggins model gave a good quantitative fit for the solvent activities in the copolymer solutions.

This study aims to identify the effect of using the blended learning method on students' academic achievement and satisfaction level in a university course for female student teachers who follow the General Teaching Method Course (304) at the College of Basic Education in Kuwait. The content of the course (304) was based on the five stages of the ADDIE instructional design model, comprising five phases: (1) Analysis, (2) Design, (3) Development, (4) Implementation, and (5) Evaluation. The research questions of the study can be summarised in two main questions: 1. What is the effect of using the method of blended learning in the General Teaching Method Course (304) on students’ academic achievement, compared to using face–to–face approaches to learning alone? 2. What is the effect of using the method of blended learning in the General Teaching Method Course (304) on students’ satisfaction, compared to using face–to-face approaches to learning alone? The researcher answered these questions through a mixed method research approach using the Explanatory Sequential Design, in order to determine the nature and objectives of the study. In this, the researcher started with the collection and analysis of quantitative data (using a quasi-experimental approach), which has priority for addressing the two research questions, and then followed this with the collection and analysis of qualitative data (using group interviews) to help explain the quantitative results. The researcher identified the study sample as 96 female students’ teachers at the College of Basic Education in Kuwait. The sample consisted of a first experimental group (n= 39)who followed the General Teaching Method Course (304) by blended learning using virtual learning environment (VLE) of Blackboard, a second experimental group (n=31) who followed the course (304) by blended learning using personal learning environment (PLE) of Facebook, and the control group (n= 26) who followed the course (304) using face-to-face approaches to learning alone. The dependent variables were academic achievement (as assessed in the course’s midterm, final and practical exams) and students’ satisfaction (as assessed by the questionnaire, giving a total mark and 3 sub-marks in reference to the students’ satisfaction about the teaching method of the course, the content of the course, and the instructor's support during the course). When answering the first question of the research, the study found that there was a significant difference in both mid-term and final tests between the first experimental group (studying through the blended learning method using VLE of Blackboard) and the control group (studying through face-to-face learning alone). However, there was no significant difference in both mid-term and final tests between the second experimental group (studying through the blended learning method using PLE of Facebook) and the control group. And there was also no significant difference in the practical test between the two experimental groups (each separately) and the control group. When answering the second question of the research, the study found that there was a significant difference in the teaching method dimension of the satisfaction questionnaire between the two experimental groups (each separately) and the control group. And there was also a significant difference in the instructor’s support dimension of the satisfaction questionnaire between the first experimental group and the control group, but no significant difference was found between the second experimental group and the control group. There was also no significant difference in the course content dimension of the satisfaction questionnaire between the two experimental groups (each separately) and the control group.

Today popular learning management systems (LMS) lack interactivity. Interactivity is very important in the learning process, because it‘s a great mean of interest and motivation. The level of interactivity could be increased by using scripts, but some of the modern scripting languages are not universal, and the majority are too hard to comprehend for non-IT specialists. That’s why a brand new scripting language has been created. It can be integrated to an open-source PHP based LMS and because of it‘s simplicity and usage of native language in syntax is rather easy to learn for non-IT staff. Experiments showed that it‘s rather convenient, compared to other similar languages and it’s speed does not slow down the process of webpage generation to an extent a user would notice. It’s also capable of performing basic mathematical and other scientific task modeling, making the language sufficient for common use. The script language has some of the complex template language properties, so it can be also used as a tool of managing content rendering. Practical integration of the script language with “Google Maps” service and VRML showed that it can be expanded to the required extent. Further works with this language may include expansion of syntax and implementation of AJAX technology.

Os líquidos iônicos são uma das principais apostas para revolucionar a química no século XXI. Em geral, apresentam propriedades como baixa pressão de vapor, alta estabilidade térmica, e ampla existência liquida e outras que os tornam interessantes para aplicações como solventes para extração, meio reacional e como meio catalítico. Estas propriedades permitem a redução da geração de efluentes industriais, o que os torna potenciais solventes verdes. O interesse recente aumentou a quantidade de ânions e cátions disponíveis para formar líquidos iônicos. Essa maior diversidade por um lado aumenta o potencial de aplicação industrial dos líquidos iônicos, mas por outro aumenta a carga de trabalho para obter as propriedades necessárias para projeto industrial destas novas substâncias. Métodos preditivos podem ser utilizados para evitar a grande demanda de ensaios experimentais para obter essas propriedades. Entretanto modelos puramente preditivos, como o COSMO-RS, usualmente não obtém uma acurácia adequada para o uso industrial. Modelos que fazem uso de dados experimentais de misturas para estimar seus parâmetros, como o UNIFAC (Do) e o F-SAC, são predominantes na indústria. Esses modelos, que são modelos de coeficiente de atividade, permitem o cálculo de equilíbrio de fases e outras propriedades termodinâmicas. Este trabalho teve como objetivo o desenvolvimento do modelo F-SAC para líquidos iônicos. Baseado em trabalhos anteriores, foram reestimados os parâmetros dos grupos de líquidos iônicos já existentes e adicionados novos grupos de cátions e ânions. Também foram geradas as primeiras curvas de equilíbrio líquido-vapor de misturas contendo líquidos iônicos com o F-SAC. De forma geral, para os 1-alquil-3-etil-imidazólios, foi obtido um R2 de 0.9794 e o valor de AAD de 0.1721 para 1514 misturas com o modelo F-SAC, superior ao encontrado para o UNIFAC (Do). Para o piridínio e o pirrolidínio o F-SAC obteve, respectivamente, um R2 de 0.9281 e 0.9837 e um valor de AAD de 0.2749 e 0.0962. Com este trabalho é possível formar 24 diferentes líquidos iônicos base com o uso de 33 parâmetros eletrostáticos estimados e 22 parâmetros geométricos no F-SAC. Para o mesmo objetivo o modelo UNIFAC (Do) necessitaria de 180 parâmetros binários e 26 parâmetros individuais – todos estimados. Ou seja, o F-SAC, nesse caso, precisou estimar apenas 27% do número de parâmetros que o UNIFAC (Do). / Ionic Liquids are one of the most promising fields to revolutionize chemistry in the 21st century. In general, they show properties like negligible vapor pressure, high thermal stability, wide liquid existence turn them interesting for applications as solvents for extraction, as reactional and catalytic media. These properties allow a reduction in industrial effluent production, making them eligible green solvents. Recent inteerest expanded the number of anions and cations available to compose Ionic. This great diversity enhances the industrial application potential of Ionic Liquids, while increases the workload needed for obtaining properties of these new substances needed for industrial project. Predictive methods can used to avoid the demand of experiments to obtain these properties. Purely predictive methods, as COSMO-RS, are usually not accurate enough for industrial use. Models use experimental data from mixtures for parameter estimation like UNIFAC (Do) and F-SAC, are predominant in the industry. Activity coefficient models like these allow the solving of phase equilibria and other thermodynamic properties. This work aimed at developing the F-SAC model for Ionic Liquids. Based on previous works, the already existing parameters for Ionic Liquid groups were reestimated and new cation and anion groups were added. In addition, the first vapor-liquid equilibrium curves for mixtures containing Ionic Liquids were created for the F-SAC model. For 1-alkyl-3-ethyl-imidazoliums, an overall R2 of 0.9794 and AAD of 0.1721 for 1514 mixtures was obtained, superior to UNIFAC (Do) values. For pyridinium and pyrrolidinium, F-SAC achieved, respectively, R2 of 0.9281 and 0.9837 and AAD of 0.2749 and 0.0962. With this work is possible to form 24 different base Ionic Liquids with 33 estimated electrostatic parameters and 22 geometric parameters with F-SAC. For the same purpose, UNIFAC (Do) would need 180 binary parameters and 23 individual parameters – all estimated. For this particular case the F-SAC model needed to estimate only 27% of the parameter number UNIFAC (Do) needed.