Made available in DSpace on 2015-04-17T14:49:43Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1163393 bytes, checksum: bfcbc24af43a50f24de2784f58cf2567 (MD5) Previous issue date: 2010-09-09 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Calcium is an essential nutrient required for numerous biological functions. Its deficiency may contribute to the emergence of several chronic diseases. In this study the goal was to obtain a new formulation of bread enriched with whey powder and calcium carbonate, whose concentration is able to classify the product as a food rich in calcium. Were first prepared loaf bread with 7.5% whey powder and different concentrations of calcium carbonate (0.63%, 1.13%, 1.75%, 2.38% and 3.00%). The products obtained had their microbiological, physicochemical and sensory evaluation. Tests were conducted sensory acceptance and purchase intent with the five formulations prepared. The concentration of calcium at all concentrations produced was determined. The chemical composition of the final product was determined on the basis of physico-chemical and sensory. A test of consumer acceptance and attitudes was conducted with groups of different life stages. The microbiological characteristics of whey powder and sliced bread were in accordance with the standards established in legislation. As for the physical and chemical characteristics of bread, there was an increase in pH and acidity decrease with the the high concentration of calcium carbonate, which hampered slightly reduced specific volume at a concentration above 2.38%. The five formulations were developed well accepted and did not differ between groups (p> 0.05), the intention to purchase the formulations with a concentration 0.63%, 1.13% and 2.38% calcium carbonate had an average ≥ a 4.0, however, there was no significant difference (p> 0.05) between formulations. Among the concentrations produced only 0.63% of calcium carbonate was not classified as food rich in calcium. The concentration of 2.38% calcium carbonate was selected as a final product based on the results of physico-chemical and sensory tests, reaching 78% of the RDA for adults. The sensory tests with groups of different stages of life showed that the enrichment of sliced bread with whey powder and calcium carbonate is accepted by the population as well as commercially viable in view of the consumer attitude shown by them. / O cálcio é um nutriente essencial necessário em diversas funções biológicas. Sua deficiência pode contribuir para o surgimento de várias doenças crônicas. Neste trabalho, o objetivo foi obter uma nova formulação de pão de forma enriquecido com soro de leite em pó e carbonato de cálcio, cuja concentração permita classificar o produto como alimento rico em cálcio. Primeiramente foram elaborados pães de forma com 7,5% de soro de leite em pó e diferentes concentrações de carbonato de cálcio (0,63%, 1,13%, 1,75%, 2,38% e 3,00%). Os produtos obtidos tiveram suas características microbiológicas, físico-químicas e sensoriais avaliadas. Foram determinados o Número Mais Provável (NMP) de coliformes totais e fecais (NMP/mL) e pesquisa de Salmonella, pH, acidez, volume específico e umidade. Na avaliação sensorial realizaram-se testes sensoriais de aceitação e intenção de compra com as cinco formulações elaboradas. A concentração de cálcio em todas as concentrações elaboradas foi determinada. A composição química do produto final foi determinada, com base nos testes físico-químicos e sensoriais. Um teste de aceitação e atitude de consumo foi realizado com grupos de diferentes estágios de vida. As características microbiológicas do soro de leite em pó e dos pães de forma estavam de acordo com os padrões estabelecidos na legislação. Quanto às características físico-químicas dos pães, foi observado um aumento no pH e diminuição da acidez com o a elevação da concentração de carbonato de cálcio, o que prejudicou ligeiramente redução do volume específico na concentração acima de 2,38%. As cinco formulações elaboradas tiveram boa aceitação não diferindo entre si (p>0,05), quanto à intenção de compra as formulações com concentração 0,63%, 1,13% e 2,38% de carbonato de cálcio tiveram médias ≥ a 4,0, no entanto, não foi verificada diferença significativa (p>0,05) entre as formulações. Dentre as concentrações elaboradas apenas a 0,63% de carbonato de cálcio não foi classificada como alimento rico em cálcio. A concentração 2,38% de carbonato de cálcio foi selecionada como produto final com base nos resultados da avaliação físico-química e dos testes sensoriais, alcançando 78% da IDR de adultos. Os testes sensoriais com grupos de diferentes estágios de vida mostraram que o enriquecimento de pães de forma com soro de leite em pó e carbonato de cálcio é aceito pela população, bem como viável comercialmente, tendo em vista a atitude de consumo por eles demonstrada.

La demande actuelle croissante d’excipients multifonctionnels par les laboratoires pharmaceutiques, amène les fabricants de matières premières à développer de nouveaux matériaux pouvant répondre à ces critères de performance. Parmi les différents procédés disponibles pour de telles productions, les techniques de co-traitement sont les plus sollicitées. Considérant l’évaluation de la fonctionnalité de différents excipients désintégrants, l’objectif de cette thèse a été de développer un tel excipient, original, économiquement intéressant et pouvant être utilisé dans la fabrication de comprimés par compression directe.Dans ce travail, nous nous sommes tout d’abord intéressés à étudier et à comparer la fonctionnalité de différents désintégrants commerciaux, en évaluant notamment l’influence des milieux réactionnels sur cette fonctionnalité.La chitine, deuxième polysaccharide naturel le plus abondant au monde, et présentant des propriétés physico-chimiques et pharmacotechniques pertinentes, a retenu notre intérêt. Un mélange co-processé, de chitine et de carbonate de calcium (CC) a été développée, et sa préparation optimisée afin de pouvoir disposer d’un matériau aux propriétés maîtrisées. Par des études conduites sur simulateur de compression, nous avons pu, d’une part, établir un profil complet de compression du CC, d’autre part, évaluer ses performances en compression directe en le formulant avec des proportions variables de composants actifs pharmaceutiques retenus comme traceurs modèles. Des études de stabilité ont enfin été réalisées, afin de déterminer ses meilleures conditions d’utilisation.Les résultats les plus marquants ont montré que la chitine présente une comprimabilité satisfaisante et des propriétés de désintégration qui ne sont pas influencées par l’environnement physico-chimique de la formulation. L’excipient co-processé CC a révélé des propriétés très intéressantes et notamment, une densité vraie et une coulabilité améliorées, par rapport à la chitine seule. Ses propriétés désintégrantes sont également particulièrement notables (comprises entre 2 et 5 s.). Son comportement en compression est par ailleurs très satisfaisant avec, une comprimabilité, une compressibilité et une compactibilité performantes; il est également à noter, que dans nos conditions de formulations, il n’a pas nécessité l'addition de lubrifiant. Les comprimés élaborés avec les composants actifs modèles ont fourni des profils de compression également performants et des aptitudes à la désintégration très satisfaisantes. Quant aux profils de dissolution pharmaceutique, ils ont révélé que, avec une teneur en CC égale à 30% m/m, la libération des actifs était rapide. Les études de stabilité conduites afin de définir les conditions optimales de conservation, ont montré que des précautions de température et d'humidité doivent être prises pour les produits formulés avec CC.L’excipient CC co-traité développé dans cette Etude présente toutes les caractéristiques d’un excellent excipient multifonctionnel (diluant, désintégrant, liant). Valorisant l’usage d’une matière première de base naturelle et très abondante (la chitine), facile à produire et économiquement rentable, il devrait pouvoir trouver un intérêt dans la formulation et la production de comprimés à dissolution rapide par compression directe. / Nowadays, there is an increasing demand for multifunctional excipients that replaces the need and use of multiple excipients. Pharmaceutical excipients coprocessing techniques represent important methods for new excipients development with enhanced functionalities. The objective of this thesis is to develop a cost-effective multifunctional excipient (filler-disintegrant-binder) used in tablet manufacturing by direct compression.In this thesis, we’ve studied and compared disintegrants functionality for different materials and evaluated the effect of media on their disintegrant’s functionality. In addition, chitin was chosen as a base to develop a multifunctional excipient used in direct compression as it showed a good and promising physicochemical and pharmaceutical properties. Chitin-Calcium carbonate (CC) coprocessed excipient was developed and its production was further optimized to ensure better powder properties and functionality. In addition, CC compression profile was established by studying its compression behavior under different conditions and formulating with active pharmaceutical ingredients to determine how it affects the formulation at different percentages. Finally, stability study was carried out to determine best conditions for the excipient handling.Results showed that chitin has good tabletability and disintegration properties that were not influenced by the physicochemical environment of the formulation. CC showed an enhancement in true density and flowability (that are considered as drawbacks for raw chitin use as an excipient) and fast disintegration (2-5s). The excipient had good tabletability, compressibility, compactibility, and it doesn’t need the use of a lubricant. CC showed a good compression profile at different manufacturing conditions (multiple lubrication levels, compression speeds and dwell times) while maintaining fast disintegration. It causes rapid disintegration and dissolution when formulated with active pharmaceutical ingredients starting from 30% w/w, and its inclusion was reflected positively on tablets strength. Stability studies showed that precautions on temperature and humidity conditions would need to be taken on CC formulated products. The results showed that the excipient serves as an excellent multifunctional excipient (filler, disintegrant, binder) used for fast disintegrating tablets produced by direct compression. It represents a cost-effective product that is efficient and easily produced at pilot plant and upon scale-up.

Este trabalho traz como proposta a obtenção de nanocompósitos (PLA/HDPE-g-AM/HDPE-Verde/n-CaCO3) com propriedades mecânicas e de fluxo adequadas para aplicação no setor de embalagens. A produção desses nanocompósitos ocorreu por meio de uma mistura de PLA e polietileno proveniente de fonte renovável (HDPE-Verde), viabilizada pela ação do agente compatibilizante polietileno enxertado com anidrido maleico (HDPE-g-AM) e do aditivo carbonato de cálcio nanoparticulado (n-CaCO3), através do estudo das condições ótimas de processamento e composição, realizado por meio do Planejamento Fatorial Delineamento Composto Central Rotacional (DCCR). A obtenção deste balanço ótimo se deu ao se avaliar a influência dos fatores de estudo velocidade de rotação (100-400rpm), teor da fase dispersa PLA 2003D (0-35%) e teor da nanocarga mineral - n-CaCO3 (1-4%) sobre as propriedades mecânicas, térmicas, morfológicas e de fluxo dos nanocompósitos, através das variáveis de resposta - módulo de Young, resistência ao impacto, grau de cristalinidade (c) e índice de fluidez (MFI).Avaliações preliminares conduziram à escolha do PLA como fase dispersa dos compósitos. As variáveis de resposta do planejamento indicaram que a viscosidade dessas amostras é diretamente proporcional à concentração de n-CaCO3 e a velocidade de processamento, por promoverem, respectivamente, maior resistência ao escoamento e dispersão da carga. As composições apresentaram como característica resistência ao impacto similar ao comportamento do PLA puro e em contrapartida, módulo de Young similar a matriz de HDPE-Verde. A cristalinidade dos polímeros foi melhorada, observando-se uma ação mútua do HDPE-Verde e do PLA para este aumento, havendo ainda colaboração do n-CaCO3 e da velocidade de mistura. A morfologia dos compósitos foi função da velocidade que favoreceu maior dispersão e distribuição da fase dispersa e ainda por maiores teores de n-CaCO3 que ocasionaram a formação de gotas de PLA de menores dimensões, favorecendo uma estrutura mais homogênea. Maiores teores de PLA alteraram a morfologia dos compósitos, ocasionando a formação de grandes domínios dessa fase na forma de gota que atribuíram ao material maior rigidez. A avaliação individual do efeito do n-CaCO3 sobre o PLA e o HDPE-Verde individualmente apontaram que a ação da carga mineral em geral é benéfica para a melhoria das propriedades, com exceção da resistência ao impacto. Além disso, os resultados mostram que a compatibilizante HDPE-g-AM também minimiza a atuação da carga. Em relação à influência do HDPE-g-AM sobre a mistura HDPE-Verde/PLA é possível observar que a compatibilização da mistura tende a ocorrer, porém não de forma eficiente como o esperado

Este trabalho traz como proposta a obtenção de nanocompósitos (PLA/HDPE-g-AM/HDPE-Verde/n-CaCO3) com propriedades mecânicas e de fluxo adequadas para aplicação no setor de embalagens. A produção desses nanocompósitos ocorreu por meio de uma mistura de PLA e polietileno proveniente de fonte renovável (HDPE-Verde), viabilizada pela ação do agente compatibilizante polietileno enxertado com anidrido maleico (HDPE-g-AM) e do aditivo carbonato de cálcio nanoparticulado (n-CaCO3), através do estudo das condições ótimas de processamento e composição, realizado por meio do Planejamento Fatorial Delineamento Composto Central Rotacional (DCCR). A obtenção deste balanço ótimo se deu ao se avaliar a influência dos fatores de estudo velocidade de rotação (100-400rpm), teor da fase dispersa PLA 2003D (0-35%) e teor da nanocarga mineral - n-CaCO3 (1-4%) sobre as propriedades mecânicas, térmicas, morfológicas e de fluxo dos nanocompósitos, através das variáveis de resposta - módulo de Young, resistência ao impacto, grau de cristalinidade (c) e índice de fluidez (MFI).Avaliações preliminares conduziram à escolha do PLA como fase dispersa dos compósitos. As variáveis de resposta do planejamento indicaram que a viscosidade dessas amostras é diretamente proporcional à concentração de n-CaCO3 e a velocidade de processamento, por promoverem, respectivamente, maior resistência ao escoamento e dispersão da carga. As composições apresentaram como característica resistência ao impacto similar ao comportamento do PLA puro e em contrapartida, módulo de Young similar a matriz de HDPE-Verde. A cristalinidade dos polímeros foi melhorada, observando-se uma ação mútua do HDPE-Verde e do PLA para este aumento, havendo ainda colaboração do n-CaCO3 e da velocidade de mistura. A morfologia dos compósitos foi função da velocidade que favoreceu maior dispersão e distribuição da fase dispersa e ainda por maiores teores de n-CaCO3 que ocasionaram a formação de gotas de PLA de menores dimensões, favorecendo uma estrutura mais homogênea. Maiores teores de PLA alteraram a morfologia dos compósitos, ocasionando a formação de grandes domínios dessa fase na forma de gota que atribuíram ao material maior rigidez. A avaliação individual do efeito do n-CaCO3 sobre o PLA e o HDPE-Verde individualmente apontaram que a ação da carga mineral em geral é benéfica para a melhoria das propriedades, com exceção da resistência ao impacto. Além disso, os resultados mostram que a compatibilizante HDPE-g-AM também minimiza a atuação da carga. Em relação à influência do HDPE-g-AM sobre a mistura HDPE-Verde/PLA é possível observar que a compatibilização da mistura tende a ocorrer, porém não de forma eficiente como o esperado

Esta pesquisa teve como objetivo analisar a remoção de cistos de Giardia spp. e oocistos de Cryptosporidium spp. em água de abastecimento utilizando a tecnologia de tratamento de ciclo completo com flotação (coagulação, floculação, flotação e filtração) em escala de bancada e utilizando cloreto de polialumínio – PAC como coagulante. Para isso, o método de floculação em carbonato de cálcio – FCCa com e sem a separação imunomagnética – IMS foi utilizado para quantificação dos organismos. Os resultados mostraram que as etapas de coagulação, floculação e flotação (Fase1) removeram 1,55 log de cistos de Giardia spp. e 1,21 log de oocistos de Cryptosporidium spp. O tratamento apenas com filtração (Fase 2) removeu 1,2 log de cistos de Giardia spp. e 0,88 log de oocistos de Cryptosporidium spp. A combinação dos tratamentos (Fase 3) foi capaz de remover 2,64 log de cistos de Giardia spp. e 2,5 log de oocistos de Cryptosporidium spp. Na quantificação de protozoários, o método de FCCa sem IMS demonstrou ser mais econômico e com melhor recuperação do que com IMS. Também foi analisada a influência da terceira dissociação ácida no método com IMS e tal procedimento acarretou em diferenças significativas nos resultados. Mesmo atendendo aos padrões de potabilidade, o tratamento estudado não removeu completamente os protozoários, este fato demonstra a necessidade da preservação dos mananciais, do tratamento dos esgotos e da desinfecção final para maximizar as barreiras que permitam reduzir o risco microbiológico presente na água de consumo. / This research aimed to analyze the removal of Giardia spp. cysts and Cryptosporidium spp. oocysts in drinking water using the full cycle of treatment with flotation technology (coagulation, flocculation, flotation and filtration) at bench scale and using polyaluminum chloride - PAC as coagulant. For this, the flocculation in calcium carbonate - FCCa method with and without immunomagnetic separation - IMS was used for quantification of organisms. The results showed that the stages of coagulation, flocculation and flotation (Step 1) removed 1,55 log Giardia spp. and 1,21 log Cryptosporidium spp. oocysts. Only the treatment with filtration (Step 2) removed 1,2 log Giardia spp. and 0,88 log Cryptosporidium spp. oocysts. The combination of treatment (Step 3) was able to remove 2,64 log Giardia spp. and 2,5 log Cryptosporidium spp. oocysts. In quantifying of protozoa, the FCCa method without IMS proved to be more economical and better recovery than with IMS. It also analyzed the influence of the third acid dissociation in the method with IMS and this procedure resulted in significant differences in the results. Even taking into account the potability standards, the treatment studied didnt completely remove protozoa, this fact demonstrates the need for preservation of water sources, treatment of sewage and final disinfection to maximize the barriers to reduce the microbiological risk present in drinking water.

L’objectif principal de cette thèse est de mieux comprendre les différents facteurs contrôlant la pompe biologique de carbone en Atlantique Nord et dans l’Océan Austral, à proximité des îles Kerguelen, en utilisant notamment deux approches: le Thorium-234 (234Th) et le baryum biogénique (Baxs).En Atlantique Nord, les flux d’export de carbone organique particulaire (POC) augmentent lorsqu’ils sont associés à des minéraux biogéniques (silice biogénique et carbonate de calcium) et lithogènes, capable de lester les particules. L’efficacité d’export, généralement plus faible que précédemment supposé (< 10%), est inversement corrélée à la production, soulignant un décalage temporel entre production et export. La plus forte efficacité de transfert, i.e. la fraction de POC atteignant 400m, est reliée à des particules lestées par du carbonate de calcium ou des minéraux lithogènes.Les flux de reminéralisation mésopélagique sont similaires ou parfois supérieurs aux flux d’exports et dépendent de l’intensité du développement phytoplanctonique, de la structure en taille, des communautés phytoplanctoniques et des processus physiques (advection verticale).Comme observé pour le POC, l’export des éléments traces est influencé par les particules lithogènes provenant des marges océaniques, mais aussi des différentes espèces phytoplanctoniques.Dans l’Océan Austral, la zone à proximité de l’île de Kerguelen est naturellement fertilisée en fer, augmentant les flux d’export de fer, d’azote et de silice biogénique. Il a été démontré que la variabilité des flux dépendait des communautés phytoplanctoniques dans la zone fertilisée. / The main objective of this thesis is to improve our understanding of the different controls that affect the oceanic biological carbon pump. Particulate export and remineralization fluxes were investigated using the thorium-234 (234Th) and biogenic barium (Baxs) proxies.In the North Atlantic, the highest particulate organic carbon (POC) export fluxes were associated to biogenic (biogenic silica or calcium carbonate) and lithogenic minerals, ballasting the particles.Export efficiency was generally low (< 10%) and inversely related to primary production, highlighting a phase lag between production and export. The highest transfer efficiencies, i.e. the fraction of POC that reached 400m, were driven by sinking particles ballasted by calcite or lithogenic minerals.The regional variation of mesopelagic remineralization was attributed to changes in bloom intensity, phytoplankton cell size, community structure and physical forcing (downwelling). Carbon remineralization balanced, or even exceeded, POC export, highlighting the impact of mesopelagic remineralization on the biological pump with a near-zero, deep carbon sequestration for spring 2014.Export of trace metals appeared strongly influenced by lithogenic material advected from the margins. However, at open ocean stations not influenced by lithogenic matter, trace metal export rather depended on phytoplankton activity and biomass.A last part of this work focused on export of biogenic silica, particulate nitrogen and iron near the Kerguelen Island. This area is characterized by a natural iron-fertilization that increases export fluxes. Inside the fertilized area, flux variability is related to phytoplankton community composition.

Le couplage covalent sur surface métallique en UHV (Ultra High Vacuum) est une technique émergente permettant de synthétiser des structures moléculaires impossibles à obtenir par la chimie en solution (nanorubans de graphène, polymères 2D par exemple). Aujourd'hui, le plus grand défi reste le développement de ces réactions sur des surfaces isolantes pour différentes applications comme, par exemple, l'électronique moléculaire. En particulier, le couplage de dérivés d'acides benzoïques, greffés sur les surfaces de carbonate de calcium en UHV par des groupes carboxyliques, a été démontré récemment pour la première fois. Lors de ces travaux, nous avons dans un premier temps synthétisé des molécules précurseurs de réactions de couplage (homo-couplage d'éthyne, photopolymérisation, polycondensation et réaction d'Ullmann) sur des surfaces de carbonate de calcium en UHV. Par la suite, nous avons mené cette étude à l'échelle macroscopique (semi-préparatoire), par greffage de molécules sur des microparticules de carbonate de calcium, puis activation de la réaction, et enfin dissolution du substrat afin d'extraire le produit final. Les microparticules ont été obtenues par broyage de produit commercial ainsi que par spray pyrolyse et complètement caractérisées par FTIR, ATG/DTG, DRX, MEB et BET. Les réactions de couplage ont été activées par deux méthodes sans solvant: par broyage dans une broyeuse planétaire ou par traitement thermique sous vide. Alors qu'en UHV le couplage de l'acide 4-iodobenzoïque donne l'acide biphenyldicarboxylique, en mécanochimie nous avons obtenu l'acide benzoïque et par activation thermique l'éther dibenzoïque. / Covalent coupling on metallic surfaces in UHV (Ultra High Vacuum) conditions is a new method for preparing molecular structures otherwise impossible to achieve in solution (graphene nanoribbons, 2D polymers for instance). The major challenge is now to extend these reactions from metallic to insulating surfaces, for future applications as, for instance, in molecular electronics. In particular, the coupling reaction of benzoic acid derivatives, grafted on calcite via carboxylic groups, has been demonstrated for the first time in UHV conditions. In the first part of this work, we synthesized precursor molecules for specific reactions (homocoupling of ethynes, photopolymerization, polycondensation and Ullmann reaction) on calcium carbonate in UHV conditions. In the second part of this work we extended this investigation up to the macroscale level (semi-preparative) by grafting molecules on calcium carbonate microparticles, followed by reaction activation and finally by dissolution of the substrate in order to recover the coupling products. The calcium carbonate microparticles were prepared by grinding commercial product or by spray pyrolysis and were fully characterized by FTIR, TG/DTG, XRD, SEM and BET techniques. Then, after grafting of organic reactant, the reactions were activated with two different solvent-free methods: by grinding in a planetary milling machine or by heating the samples in a furnace under vacuum. Whereas in UHV conditions, 4-iodobenzoic acid affords biphenyldicarboxylic acid, mechanochemical condition gives benzoic acid and thermal activation the dibenzoic acid ether.

Ce travail a eu pour objectif la création de matériaux composites à base de nanocharges de carbonate de calcium. L'étude des phénomènes interfaciaux qui régissent ces systèmes, ainsi que leurs impacts sur les propriétés fonctionnelles du matériau et plus particulièrement des propriétés de transport, ont été réalisées. Pour ce faire, nous avons considéré deux matrices polymères de nature chimique différente : le polylactide et le polyfluore de vinylidène. Les nanocomposites ont été élaborés par deux voies de mise en œuvre : la voie fondu et la voix solvant. Une analyse fine des relations structure/morphologie/propriétés des composites a été réalisée. Nous avons mis en évidence, quelle que soit la matrice polymère choisie, l'importance du traitement de surface des charges afin d'améliorer leurs états de dispersion dans le matériau et d'augmenter la qualité de l'interface charge/polymère. Ces paramètres ont été corrélés aux propriétés de transport de ces matériaux composites. / The aim of this PhD work is to elaborate composites based on calcium carbonate nanoparticles. Polylactide and polyvinylidene fluoride were used as polymer matrix and nanocomposite were elaborated either by melting process and either by casting method. The interfacial behaviour between polymer and calcium carbonate were studied and we especially focused on their impact on the composite gas barrier properties. The importance of filler surface treatment had been highlighted on the filler dispersion state improvment and filler/polymer interface reinforcement. Both parameters were important in the improvement of composite gas barrier properties.

A modified two-element membrane pressure vessel assembly has been used to monitor process operational changes in a full-scale reverse osmosis (RO) water treatment plant (WTP). This study evaluated the effectiveness of the assembly as an on-line monitoring device intended to detect scale formation conditions when connected to an operating RO process train. This study was implemented to support the requirements of a larger University of Central Florida (UCF) research project ongoing at the city of Sarasota’s Public Works and Utilities (City) water treatment facilities located in Sarasota, Florida. During the time-frame of this study, the City was in the process of eliminating their sulfuric acid feed from the pretreatment system of their existing 4.5 million gallon per day (MGD) RO membrane process. The City was motivated to eliminate its dependence on sulfuric acid to reduce operating costs as well as reduce operation health and safety risks associated with the use of the acid as a pretreatment chemical. Because the City was concerned with secondary process impacts associated with acid elimination, additional measures were desired in order to protect the full-scale process. This thesis reports on the design, fabrication and installation of a third-stage two membrane element pressure vessel “canary” sentinel monitoring device (Canary), its effectiveness as an online scaling monitor during full-scale acid elimination, and presents the results of the study. The Canary sentinel device was controlled using the normalized specific flux of the two membrane elements fed by a portion of the second stage concentrate of one of the City’s full-scale RO process skids. Although the Canary demonstrated the ability to detect changes in an RO process operation, scaling did not occur under the conditions evaluated in this study. An autopsy of one iv of the Canary elements revealed that no scaling had occurred during the acid elimination process. Therefore, the Canary was found to be useful in its function as a sentinel, even though no scaling was detected by the device after acid elimination at the City’s full-scale plant had been accomplished.

This doctoral work was developed in the frame of bone tissue engineering, dealing with the fabrication of scaffolds for the regeneration of bones. At this purpose, calcium phosphates derived from natural sources are very interesting because they are more similar to the bone mineral and possess better bioactivity. Indeed, the bone mineral is different from synthetic hydroxyapatite as it is non-stoichiometric, nanosized, it presents a high degree of disorder and contains many additional ions and impurities such as CO32-, Mg2+, Sr2+, Na+, etc. These characteristics can be easily obtained by synthesizing hydroxyapatite from natural sources, such as corals, starfishes, seashells, animal bones, bird eggshells etc. The natural sources used in the present work are three types of biogenic calcium carbonate, i.e. calcium carbonate that is produced by living organisms in the form of aragonite or calcite. Among the different sources, three biogenic calcium carbonates were chosen: cuttlefish (Sepia Officinalis) bones, mussel (Mytilus Galloprovincialis) shells and chicken eggshells. Besides their abundance and availability, they were selected because of their different composition: aragonite in cuttlebones, calcite in eggshells and a mixture of aragonite and calcite in mussel shells. After the first chapter, which is a theoretical introduction, this thesis is divided into other five chapters. Chapter 2 contains a careful characterization of the three biogenic raw materials while Chapter 3 deals with the synthesis of hydroxyapatite starting from these natural sources. The process developed here takes place entirely at nearly room temperature, which allows the organic part of the biological materials to be preserved. This synthesis process is basically a wet mechanosynthesis followed by a mild heat treatment (up to 150°C). The study focuses on the influence of several process parameters on the synthesis efficiency: temperature, milling time, pH and raw material. The temperature used to dry the slurry after the wet ball-milling was found to be the most important parameter, the higher the temperature the faster the conversion of CaCO3 into hydroxyapatite. Moreover, aragonite was found to transform more easily into hydroxyapatite with respect to calcite, and also to follow a different reaction path. The synthesis process described in Chapter 3 allowed to produce different bio-derived powders that were found to be non-stoichiometric, nanosized, carbonated hydroxyapatites, containing also additional ions, especially Mg2+ in the eggshell-derived material and Sr2+ in the cuttlebone-derived one. These powders were then used as a starting point for the studies presented in the next three chapters. Chapter 4 shows a very preliminary evaluation of the interaction with human cells in vitro. First, the as-synthesized powders were consolidated by uniaxial pressing and sintering at temperatures between 900°C and 1100°C and their crystallographic composition was analyzed. Then, after having established the non-cytotoxicity of the sintered pellets, osteoblasts from human osteosarcoma cell line were seeded on the pellets and their behavior after 1, 3 and 5 days of culture was observed by confocal microscopy. In general, all materials promoted good cell adhesion and proliferation, especially the eggshell-derived one. At this point, the bio-derived materials were found to induce a good cellular response but, in order to foster the regeneration of bones, a scaffold must also contain a large amount of interconnected porosity. Among the numerous methods to fabricate porous structures, additive manufacturing is surely very attractive due many advantages, such as the possibility of customizing the shape based on tomography images from the patients, the fact that no mold is needed and the freedom of fully designing the porosity. Indeed, not only the size and the amount of porosity are important, but also the shape of the pores and their position and orientation have a deep effect on the interaction with the cells. Therefore, Chapter 5 and Chapter 6 deal with the fabrication of scaffolds by 3D printing, following two different approaches. In the study presented in Chapter 5, the powders synthesized from cuttlebones, mussel shells and eggshells were used in combination with a thermoplastic polymer (PCL, polycaprolactone) to obtain bioactive composites. Composite materials made of 85 wt% PCL and 15 wt% bio-derived hydroxyapatite were used to fabricate porous scaffolds by extrusion 3D printing. The biological in vitro tests showed that the composite scaffolds possess better bioactivity than the pure PCL ones, especially those containing mussel shell- and cuttlebone-derived powders, which promoted the best cell adhesion, proliferation and metabolic activity of human osteosarcoma cells after 7 days of culture. In addition, the elastic compressive modulus, which was found to be between 177-316 MPa, thus in the range of that of trabecular bone, was found to increase of about ∼50% with the addition of the bio-derived nanopowders. Finally, in Chapter 6, the cuttlebone-derived powder was used to fabricate porous bioceramic scaffolds by binder jetting 3D printing. Due to serious technical issues related to the printing of a nanosized powder, 10 wt% of bio-derived powder was mixed with a glass-ceramic powder with bigger particle size. Moreover, the organic part of the cuttlebone had to be previously eliminated by a heat treatment at 800°C. Thanks to the great freedom of design that is allowed by the binder jetting process, scaffolds with two different pore geometries were fabricated: with pores of uniform size and with a size-gradient. Indeed, natural bone possesses a gradient in porosity from the core to the surface, from porous trabecular bone to dense cortical bone. The sintered scaffolds showed a total porosity of ∼60% for the pure glass-ceramic and ∼70% for the glass-ceramic with 10 wt% of cuttlebone-derived nanoparticles, which most probably slowed down the densification by limiting the contact between the glassy particles. All the bioceramic scaffolds promoted good adhesion and proliferation of human bone marrow-derived mesenchymal stem cells in vitro, without any significant difference between the different samples. However, the scaffolds with the cuttlebone-derived powder and with gradient porosity showed the greatest decrease of metabolic activity after 10 days of culture, which could be accounted as a sign of differentiation of stem cells.