In this study, pharmaceutical-grade and food-grade linker-based lecithin self-emulsifying delivery systems (SEDS) were developed with a combination of lipophilic and hydrophilic linkers. These additives at suggested concentrations are safe for pharmaceutical and food applications. The ratio of surfactant lecithin and linkers in these systems was optimized to develop surfactant in oil preconcentrates. The preconcentrates containing different surfactant concentrations and oil were diluted with fed state simulated intestinal fluid to produce pseudo-ternary phase diagrams and to identify the formulations that produced self-emulsifying or self-microemulsifying delivery systems. Optimal SEDS preconcentrates were evaluated using a dialyzer model to simulate intestinal uptake. An uptake of 39.6 mg/cm2 for the pharmaceutical-grade SEDS was obtained within 72 minutes, which promises substantial improvement in the bioavailability of hydrophobic actives. The optimal uptake of 12.2 mg/cm2 for food-grade SEDS suggests enhancement in the bioavailability of omega-3 fatty acids.

Network structures based upon metal-organic backbones represent a new class of functional materials that can be rationally constructed by employing the concepts of supramolecular chemistry and crystal engineering. The modularity of design strategies, the diversity of prototypal structures, and the dynamic features of networks have afforded great advantages over traditional materials syntheses. The research presented in this dissertation is primarily concerned with developing an in-depth understanding of the basic principles that govern the supramolecular behaviors of metal-organic frameworks and gaining an experimental control over the structure and function of these new classes of hybrid materials. The use of rigid and angular organic ligands along with transition metal clusters gives rise to a wide variety of novel metal-organic architectures ranging from zero-dimensional nanostructures to three-dimensional frameworks. Gas sorption experiments suggest some of these compounds are potentially useful as porous materials. Conformational analysis of these structural models reveals geometrical foundations for the existence of superstructural diversity. Controlled crystallization experiments further indicate synthetic factors that might determine the formation of supramolecular isomers. On the other hand, careful selection of more labile organic components leads to flexible metal-organic frameworks exhibiting dynamic characteristics that have not been observed in their rigid counterparts. The guest-dependent switch-on/off of cavities and the ease of fine-tuning their chemical environments demonstrate the effectiveness of such a strategy in the context of generating tailored functional materials. Discovery and recognition of novel three-periodic metal-organic nets remains a nontrivial exercise. In this context, rigorous topological analysis assists the understanding of complicated nets and application of geometrical principles facilitates desing of new metal-organic structures. Finally, scaled-up metal-organic frameworks are potentially accessible with the aid of existing prototypal structures and a systematic study on ligand design.

Η ανάπτυξη νέων τεχνολογιών ανανεώσιμων πηγών ενέργειας τα τελευταία χρόνια, έχει γίνει αναγκαία με τη συνεχόμενη περιβαλλοντική ρύπανση και την αλόγιστη σπατάλη των φυσικών πόρων. Οι τεχνολογίες υδρογόνου και ειδικά η παραγωγή υδρογόνου μέσω της διαδικασίας της ηλεκτρόλυσης έχει αρχίσει να κερδίζει σημαντικό έδαφος τα τελευταία χρόνια με τη συνεχιζόμενη ανακάλυψη νέων υλικών, αποδοτικών και με χαμηλό κόστος. Στην παρούσα εργασία θα αναλύσουμε την τεχνολογία παραγωγής υδρογόνου με ηλεκτρόλυση καθώς και την παρασκευή υλικών με τη μέθοδο της ηλεκτροχημικής εναπόθεσης διμεταλλικών και τριμεταλλικών λεπτών υμενίων μεταβατικών μετάλλων με βάση το Νικέλιο (Ni). Τα κράματα Νικελίου με προσθήκη άλλων μετάλλων όπως Fe, Co, Mo κ.α. έχουν τεράστιο ερευνητικό ενδιαφέρον λόγω των πολύ καλών ηλεκτροκαταλυτικών ιδιοτήτων που παρουσιάζουν όσον αφορά την παραγωγή υδρογόνου, καθώς παρουσιάζουν καλύτερες ιδιότητες και από την Πλατίνα(Pt), που αποτελεί το αποδοτικότερο αλλά και το ακριβότερο μέταλλο που έχει χρησιμοποιηθεί ως καταλύτης για παραγωγή υδρογόνου. Η τεχνολογία της ηλεκτροχημικής εναπόθεσης λεπτών υμενίων προσφέρει υλικά πορώδη, αποδοτικά, φθηνά και ανθεκτικά σε συνθήκες έντονο αλκαλικού και όξινου περιβάλλοντος. Τα υλικά που παρασκευάσαμε ήταν NiFe, NiFeZn, NiCoZn, NiCoFeZn και NiMoZn. Κύριος στόχος της εργασίας αυτής ήταν η μελέτη των συνθηκών της ηλεκτροχημικής εναπόθεσης και ο τρόπος με τον οποίο επηρεάζουν τη μορφολογία και τις ιδιότητες των λεπτών υμενίων. Αρχικά μελετήσαμε τα υμένια σε πραγματικές συνθήκες ηλεκτρόλυσης, μετρώντας την παραγωγή υδρογόνου για συγκεκριμένες πάντα συνθήκες. Στη συνέχεια έγιναν μετρήσεις υπερδυναμικού παραγωγής υδρογόνου και από τα δεδομένα αυτά και με τη βοήθεια των διαγραμμάτων Tafel υπολογίσαμε ηλεκτροκαταλυτικούς συντελεστές όπως η πυκνότητα ρεύματος ανταλλαγής και η κλίση Tafel. Τέλος μετρήσεις σε ηλεκτρονικό μικροσκόπιο σάρωσης (SEM) και στοιχειακές αναλύσεις (EDX) μας έδωσαν μια πιο ολοκληρωμένη εικόνα για την επίδραση των συνθηκών της ηλεκτροχημικής εναπόθεσης στην μορφολογία της επιφάνειας των λεπτών υμενίων και των ιδιοτήτων τους. Μελετήσαμε τις ηλεκτροκαταλυτικές ιδιότητες ενός νέου υλικού (NiCoFeZn), καταλήγοντας στο συμπέρασμα ότι είναι ένα πολλά υποσχόμενο υλικό για την παραγωγή υδρογόνου και για το λόγο αυτό πρέπει να μελετηθεί εκτενέστερα, καθώς σήμερα χρησιμοποιείται κυρίως ως μαγνητικό υλικό. / The continuous environmental pollution and the depletion of natural resources have brought forward the need for the development of new renewable energy technologies. Hydrogen technologies and especially electrolytic hydrogen production, has gained considerable ground in the recent years due to the discovery of new, efficient and low cost alloy compounds. In this work we analyze the electrolytic hydrogen production and the fabrication of electrodeposited binary and ternary Nickel-based thin film alloys. The addition of the Fe, Co, Mo transition metals in Nickel-based alloys is of great interest in terms of research, because of their great electrocatalytic properties and high hydrogen production. These alloys even surpass Platinum (Pt), which is the most efficient yet also one of the most expensive metal used as hydrogen production catalyst. The electrodeposition of thin film alloys, offers porous, inexpensive and resistive in basic and acidic environment, compounds. The alloys we fabricated were NiFe, NiFeZn, NiCoZn, NiCoFeZn and NiMoZn. Our main goal was to study the electrodeposition process conditions and the manner in which they affect the morphology and the properties of the thin film alloys. At first we studied the electrocatalytic properties of the thin film alloys during the electrolytic production process using the same conditions every time. The next step was to measure the hydrogen production overvoltage and the estimation of electrocatalytic constants such as the exchange current density and the Tafel slope using the Tafel diagrams. Finally SEM micrographs and EDX stoichiometry analysis gave more accurate results on the morphology and the electrocatalytic properties of the thin film alloys. We also studied the electrocatalytic properties of a new compound (NiCoFeZn), which is in fact a very promising compound for the electrolytic hydrogen production. Today the research around this material is mainly focused on its magnetic properties, so a thorough study of its catalytic properties would be of great importance.

Polypropylene (PP) and ethylene-co-octene copolymer (EOC) blends were prepared at various component ratios and reinforced with silica nanoparticles (SiO2). Strategies to improve filler dispersion involved the grafting of a silane coupling agent on the PP matrix, the addition of a maleated PP (PP-g-MA) as a compatibilizer and the use of hydrophobic silica nanoparticles. These approaches resulted in a fine dispersion of the nanoparticles within the PP phase and induced a reduction of the size of the EOC domains, due to a barrier effect. Tensile and flexural properties were significantly increased, whereas ductility and impact properties were not affected. These enhancements are attributed to the favourable microstructure of the blends, featuring a segregated microstructure, and to the improved interfacial adhesion between the functionalized polymer matrix and the surface of the nanoparticles. The microstructure and rheology of model melt compounded EOC-based nanocomposites were investigated. Functionalization of the polyolefin matrix was accomplished through silane grafting, or addition of a maleated EOC (EOC-g-MA) compatibilizer. Various grades of unmodified SiO2 having different specific surface areas (SSA), as well as a surface-modified grade were added to the EOC matrix at various loadings. The formation of covalent and hydrogen bonds between the silanol groups and the functionalized polymer generated strong polymer/filler (P/F) interactions, resulting in improved filler dispersion. Bound polymer characterization revealed that in the compatibilized materials, the amount of polymer physically attached to the nanoparticles was higher than in the non-compatibilized samples. In the absence of a compatibilizer, larger SiO2 aggregates formed upon increasing SSA because of increased probability of hydrogen bonding between the particles. The increased propensity for aggregation was revealed by time sweeps as well as by the increased strain sensitivity in stress sweeps. On the contrary, the compatibilized composites exhibited a stable response and a higher critical strain for the onset of non-linearity, indicative of stronger adhesion between the fillers and the matrix. Superposition of oscillatory and creep/recovery experiments revealed that the viscoelastic properties in the terminal region were influenced substantially by the state of dispersion of the nanoparticles. In the absence of a compatibilizer, substantial enhancements in the linear viscoelastic (LVE) functions were noted and an increasing SSA resulted in more significant deviations from terminal flow. On the contrary, the SSA of the particles had no effect on the viscoelastic and mechanical properties of the compatibilized composites. / Thesis (Ph.D, Chemical Engineering) -- Queen's University, 2011-04-18 15:17:52.471

En 1993, Conway et Schneeberger fournirent un critère simple permettant de déterminer si une forme quadratique donnée représente tous les entiers positifs ; le théorème des 15. Dans ce mémoire, nous nous intéressons à un problème analogue, soit la recherche d’un critère similaire permettant de détecter si une forme quadratique en trois variables représente tous les entiers impairs. On débute donc par une introduction générale à la théorie des formes quadratiques, notamment en deux variables, puis on expose différents points de vue sous lesquels on peut les considérer. On décrit ensuite le théorème des 15 et ses généralisations, en soulignant les techniques utilisées dans la preuve de Bhargava. Enfin, on démontre deux théorèmes qui fournissent des critères permettant de déterminer si une forme quadratique ternaire représente tous les entiers impairs. / In 1993, Conway and Schneeberger gave a simple criterion allowing one to determine whether a given quadratic form represents all positive integers ; the 15-theorem. In this thesis, we investigate an analogous problem, that is the search for a similar criterion allowing one to detect if a quadratic form in three variables represents all odd integers. We start with a general introduction to the theory of quadratic forms, namely in two variables, then, we expose different points of view under which quadratic forms can be considered. We then describe the 15-theorem and its generalizations, with a particular emphasis on the techniques used in Bhargava’s proof of the theorem. Finally, we give a proof of two theorems which provide a criteria to determine whether a ternary quadratic form represents all odd integers. / Les calculs numériques ont été effectués à l'aide du logiciel SAGE.

In this study, pharmaceutical-grade and food-grade linker-based lecithin self-emulsifying delivery systems (SEDS) were developed with a combination of lipophilic and hydrophilic linkers. These additives at suggested concentrations are safe for pharmaceutical and food applications. The ratio of surfactant lecithin and linkers in these systems was optimized to develop surfactant in oil preconcentrates. The preconcentrates containing different surfactant concentrations and oil were diluted with fed state simulated intestinal fluid to produce pseudo-ternary phase diagrams and to identify the formulations that produced self-emulsifying or self-microemulsifying delivery systems. Optimal SEDS preconcentrates were evaluated using a dialyzer model to simulate intestinal uptake. An uptake of 39.6 mg/cm2 for the pharmaceutical-grade SEDS was obtained within 72 minutes, which promises substantial improvement in the bioavailability of hydrophobic actives. The optimal uptake of 12.2 mg/cm2 for food-grade SEDS suggests enhancement in the bioavailability of omega-3 fatty acids.

Made available in DSpace on 2015-04-17T14:49:22Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1134733 bytes, checksum: 28cffd4f9ffcc33dac5566773d86f7c7 (MD5) Previous issue date: 2012-06-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work aimed to utilize the combined osmotic dehydration and convective drying process to obtain eggplant chips by a non-conventional healthier and more low cost way. The combined process was studied through a factorial experimental design having as independent variables the temperature (30-50°C), sucrose (27,5 to 42,5% w/w) and sodium chloride (3,75 to 6,25% w/w) solution concentrations and immersion time (142,5 to 247,5 min.). The dependent ones were the water loss (PA), sucrose gain (GSac), sodium gain (GSódio), and the GSac/GSódio ratio. Samples from each osmotic condition were dried at 60°C for 4 hours in a convective dryer with a 1m/s air velocity. The objective was to obtain a maximum water loss with a minimum sucrose and sodium impregnation. Statistic models were well fitted according to the Response Surface Methodology. Once PA was above 90% and water activity was less than 0,4 for all samples, it was used the GSac/GSódio ratio as a parameter for choosing the best process condition which should be maximum. Thus, from this analysis, the best way to obtain eggplant chips was at 50°C, with a sucrose and sodium chloride concentrations of 45% and 7,5%, respectively, for 127,5 minutes. This independent variables combination led to a final product with its sodium content sensory attenuated due the sucrose presence and based on this point of view, it could be considered a healthier product compared with similar commercial, as well as by non-use of conventional frying process. / O presente trabalho teve como objetivo a utilização da tecnologia combinada de desidratação osmótica e secagem para obtenção de berinjela seca em forma de chips , de modo a aproveitar esta matéria-prima e obter um produto final, por vias não convencionais, mais saudável e de baixo custo. O processo de desidratação osmótica seguida de secagem convectiva foi realizado através de um delineamento experimental, tendo como variáveis independentes a temperatura (30 50°C), concentração de sacarose (27,5 42,5% p/p) e concentração de cloreto de sódio (3,75 6,25% p/p) da solução osmótica e o tempo de imersão (142,5 247,5 min.), e como variáveis dependentes PA, GSac, GSódio, GSac/GSódio e aw, secas numa temperatura e tempo de 60°C e 4 horas, respectivamente, a uma velocidade de 1m/s, onde o objetivo foi obter uma máxima perda de água com uma mínima incorporação de sacarose e sódio. Foram ajustados modelos de primeira ordem segundo a metodologia de superfície de resposta. Uma vez que PA foi acima de 90% e a aw foi menor que 0,4 para todos os ensaios, utilizou-se como parâmetro de escolha da melhor condição do processo, a análise do agente osmótico, mediante a razão GSac/GSódio, a qual deveria ser máxima, segundo a composição de amostras de batata chips comerciais. A condição ideal para obtenção de berinjela seca em forma de chips foi T=50ºC, CSac=45%, CSal=7,5%, t=127,5 minutos, onde tal fato implica em um produto final com um teor de sódio sensorialmente atenuado devido à presença da sacarose e sendo considerado, portanto, mais saudável em função dos menores teores de sódio e sacarose, quando comparado com os similares comerciais, assim como também, pela não utilização do processo de fritura convencional.

Made available in DSpace on 2014-10-09T12:43:21Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:56:45Z (GMT). No. of bitstreams: 1 06435.pdf: 7431452 bytes, checksum: 52a613c5fd6687de6ee09e587bde83c2 (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

[pt] Foram estudados os sistemas binários e ternários de cobalto (II) e de níquel(II) com os aminoácidos glicina, serina, ácido aspártico e ácido guanidoacético. Os aminoácidos glicina - Gly, serina - Ser, ácido aspártico - Asp e ácido guanidoacético - Gaa estão envolvidos em muitos processos bioquímicos. Esses aminoácidos fazem parte de muitas proteínas que, por sua vez, são bons agentes complexantes. O estudo das interações metal- aminoácido tem grande interesse, visto que estas representam modelos simplificados para a análise das mudanças provocadas nas propriedades das proteínas, quando estas se ligam aos íons metálicos. Neste estudo foram determinadas as constantes de formação e de interação das espécies pertencentes aos sistemas binários e ternários de cobalto(II) e de níquel(II), e também foram realizados estudos espectrofotométricos de UVVis de todos os sistemas estudados. A comparação dos espectros de UV-Vis em diferentes valores de pH com os gráficos de distribuição de espécies permitiu relacionar as bandas d-d com as respectivas espécies propostas. Analisando as constantes de formação dos complexos ternários ML1L2, constatou-se que os complexos de Ni(II) apresentam valores mais altos que os respectivos de Co(II), o que está de acordo com a série de Irving-Williams. Comparando-se os espectros de UV-Vis com os da literatura, pode-se concluir que as bandas encontradas, assim como os seus respectivos posicionamentos e absortividades molares referem-se a complexos octaédricos não regulares. Verificou-se que as maiores interações intramoleculares dos ligantes nos complexos estudados, ocorreram com as espécies contendo Gaa. A partir dos gráficos de distribuição de espécies em função do pH, pode-se verificar que, em pH biológico, para os três sistemas de Co(II), predominam as espécies ternárias protonadas. Para os sistemas de Ni(II), não é possível generalizar. No sistema Ni-Gly-Ser a espécie NiGlySer está em maior quantidade em pH em torno de 7; no sistema Ni-Asp- Gly, as espécies ternárias formam-se em menor quantidade em valores de pH mais baixos e em pH biológio, as espécies binárias de NiAsp hidrolizadas é que predominam; no sistema Ni-Ser-Gaa, as espécies ternárias protonadas é que estão em maior concentração. Em pH ~ 9, já encontramos espécies hidrolisadas (binárias e/ou ternárias) em todos os sistemas ternários. Em meio mais básico, as espécies ternárias fragmentam-se, gerando espécies binárias hidrolisadas dos tipos ML(OH)3 e ML(OH)4 que passam a ter maiores estabilidades. / [en] The binary and ternary systems of cobalt(II) and nickel (II) with the amino acids glycine, serine, aspartic acid and guanidinoacetic acid were studied. The amino acids glycine - Gly, serine - Ser, aspartic acid - Asp and guanidinoacetic acid - Gaa are all involved in several biochemical processes. These amino acids are constituents of many proteins, which are in turn, good complexing agents. The study of metal-amino acid interactions are of great interest, as they represent simplified models for the analysis of the changes caused in the proteins` properties, when these bond to metal ions. It was determined, in this work, the formation and interaction constants of species belonging to the binary and ternary systems of cobalt(II) and nickel(II). UV-Vis spectrophotometric analysis were also made for each of the systems studied. The comparison of the UV-Vis spectra in different pHs with the species` distribution graphs indicated a relationship between the d-d bands and the respective proposed specie. When analyzing the formation constants of the ternary complexes ML1L2, the Ni (II) complexes showed higher values than those of respective Co(II) complexes, a pattern which is in accordance with the Irving-Williams series. In conclusion to the comparison of the UV-Vis spectra with those in literature, we have that the bands found, as well as their respective position and molar absortivities, refer themselves to nonregular octahedral complexes. It was verified that the greatest intramolecular interactions beetween the ligands in the complexes studied were those of the species cointaining Gaa. From the graphs of species distribution in terms of pH, we were able to verify that in biological pH, for all three systems of Co(II), protonated ternary species were predominant. No generalizations were visible for the Ni(II) systems. In the Ni-Gly-Ser system, the specie NiGlySer is present in greater amounts in pH close to 7; in the Ni-Asp-Gly system, the ternary species are formed in lower quantities in lower pH values and in higher and biological pH values, binary species of hydrolyzed NiAsp are predominant; in Ni-Ser-Gaa systems, protonated ternary species are in higher concentration. In pH ~ 9, hydrolyzed (binary and/or ternary) species were found in all ternary systems. In more basic medium, the ternary species were fragmented, therefore generating ML(OH)3 and ML(OH)4 hydrolyzed binary species, which have in turn greater stability.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / As propriedades fÃsico-quÃmicas do Ãster EtÃlico do Ãleo de Mamona (EEOM) foram estimadas a partir de modelos teÃricos e anÃlises experimentais. Por nÃo ser um combustÃvel comercial, o EEOM foi manufaturado por meio de um processo de fabricaÃÃo denominado (Transesterification Double Step Process) TDPS. AtravÃs do mÃtodo de contribuiÃÃo de grupos, as propriedades crÃticas e o ponto de ebuliÃÃo normal foram estimados. Utilizando os valores das propriedades crÃticas e correlaÃÃes matemÃticas, estimaram-se a tensÃo superficial, a entalpia de vaporizaÃÃo, a pressÃo de vapor, a condutividade tÃrmica, a viscosidade e a densidade. A anÃlise experimental do EEOM foi conduzida utilizando tÃcnicas tradicionalmente associadas à pesquisa de densidade e viscosidade de combustÃveis. Na anÃlise experimental de viscosidade utilizou-se um viscosÃmetro copo Ford. TambÃm foram analisadas experimentalmente as misturas ternÃrias do EEOM, etanol e diesel comercial em diversas fraÃÃes volumÃtricas. A anÃlise das misturas ternÃrias vem como uma alternativa para amenizar os valores de viscosidade e densidade do EEOM no combustÃvel de uso final, estimando os valores de fraÃÃes volumÃtricas que podem atender as normas brasileiras e europeias. Os resultados das propriedades fÃsico-quÃmicas servirÃo como base para rotinas computacionais de simulaÃÃo aplicadas ao estudo de emissÃes de poluentes e formaÃÃo do jato combustÃvel para o EEOM. / The physicochemical properties of the Ethyl Ester of Castor Oil (EECO) were estimated from theoretical models and experimental analysis. As it is not a comercial fuel, the EECO has been manufactured by a special fabrication process denominated (Transesterification Double Step Process) TDPS. Through the group contribution method, critical properties and normal boiling point were estimated. Using the values of the critical properties and mathematical correlations, were surface tension, enthalpy vaporization, vapor pressure, thermal conductivity, viscosity and density estimated. The experimental analysis of EEOM was conducted using techniques traditionally associated with research of density and viscosity of fuel. In the experimental analysis of viscosity it was used a Ford cup viscometer. As an alternative to alleviate the values of viscosity and density of the fuel EECO in ultimate use, as well as analyzed mixtures EECO, ethanol and diesel trade in various volume fractions, estimating the values that can meet the Brazilian and European standards. The results of the physical and chemical properties will serve as a basis for computer simulation routines applied to the study of emissions and formation of jet fuel for EECO.