Synthesis and characterisation of novel superficially porous silica based stationary phases for use in liquid chromatography

The concept of pellicular particles was suggested by Horváth and Lipsky over fifty years ago. The reasoning behind the idea of these particles was to improve column efficiency by shortening the pathways analyte molecules can travel, therefore reducing the effect of the A and C terms. Several types of shell particles were successfully marketed around this time, however with the introduction of high quality fully porous silica under 10 μm, shell particles faded into the background. In recent years a new generation of core shell particles have become popular within the separation science community. These particles allow fast and efficient separations that can be carried out on conventional HPLC systems. Chapter 1 of this thesis introduces the chemistry of chromatographic stationary phases, with an emphasis on silica bonded phases, particularly focusing on the current state of technology in this area. The main focus is on superficially porous silica particles as a support material for liquid chromatography. A summary of the history and development of these particles over the past few decades is explored, along with current methods of synthesis of shell particles. While commercial shell particles have a rough outer surface, Chapter 2 focuses on the novel approach to growth of smooth surface superficially porous particles in a step-by-step manner. From the Stöber methodology to the seeded growth technique, and finally to the layer-bylayer growth of the porous shell. The superficially porous particles generated in this work have an overall diameter of 2.6 μm with a 350 nm porous shell; these silica particles were characterised using SEM, TEM and BET analysis. The uniform spherical nature of the particles along with their surface area, pore size and particle size distribution are examined in this chapter. I discovered that these smooth surface shell particles can be synthesised to give comparable surface area and pore size in comparison to commercial brands. Chapter 3 deals with the bonding of the particles prepared in Chapter 2 with C18 functionality; one with a narrow and one with a wide particle size distribution. This chapter examines the chromatographic and kinetic performance of these silica stationary phases, and compares them to a commercial superficially porous silica phase with a rough outer surface. I found that the particle size distribution does not seem to be the major contributor to the improvement in efficiency. The surface morphology of the particles appears to play an important role in the packing process of these particles and influences the Van Deemter effects. Chapter 4 focuses on the functionalisation of 2.6 μm smooth surface superficially porous particles with a variety of fluorinated and phenyl silanes. The same processes were carried out on 3.0 μm fully porous silica particles to provide a comparison. All phases were accessed using elemental analysis, thermogravimetric analysis, nitrogen sorption analysis and chromatographically evaluated using the Neue test. I observed comparable results for the 2.6 μm shell pentaflurophenyl propyl silica when compared to 3.0 μm fully porous silica. Chapter 5 moves towards nano-particles, with the synthesis of sub-1 μm superficially porous particles, their characterisation and use in chromatography. The particles prepared are 750 nm in total with a 100 nm shell. All reactions and testing carried out on these 750 nm core shell particles are also carried out on 1.5 μm fully porous particles in order to give a comparative result. The 750 nm core shell particles can be synthesised quickly and are very uniform. The main drawback in their use for HPLC is the system itself due to the backpressure experienced using sub – 1 μm particles. The synthesis of modified Stöber particles is also examined in this chapter with a range of non-porous silica and shell silica from 70 nm – 750 nm being tested for use on a Langmuir – Blodgett system. These smooth surface shell particles have only been in existence since 2009. The results displayed in this thesis demonstrate how much potential smooth surface shell particles have provided more in-depth optimisation is carried out. The results on packing studies reported in this thesis aims to be a starting point for a more sophisticated methodology, which in turn can lead to greater chromatographic improvements.

Clean preparation of nanoparticulate metals in porous supports: a supercritical route

Here we present the synthesis of nanometre sized silver particles which have been trapped within porous substrates; poly( styrene-divinylbenzene) beads and silica aerogels. This is the first time that supercritical carbon dioxide has been used to impregnate such porous materials with silver coordination complexes. In this paper we demonstrate that control over the resultant nanoparticles with respect to size, loading and distribution in the support material has been achieved by simple choice of the precursor complex. The solubility of the precursor complexes in the supercritical solvent is shown to be one of the key parameters in determining the size of the nanoparticles, their distribution and their homogeneity within the support matrix. Moreover, we demonstrate that the same methodology can be applied to two very different substrate materials. In the particular case of aerogels, conventional organic solvents could not be used to prepare nanoparticles because the surface tension of the solvent would lead to fracturing of the aerogel structure.

Physical and electrochemical evaluation of ATO supported IrO2 catalyst for proton exchange membrane water electrolyser

Antimony doped tin oxide (ATO) was studied as a support material for IrO₂ in proton exchange membrane water electrolyser (PEMWE). Adams fusion method was used to prepare the IrO₂-ATO catalysts. The physical and electrochemical characterisation of the catalysts were carried out using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder conductivity, cyclic voltammetry (CV) and membrane electrode assembly (MEA) polarisation. The BET surface area and electronic conductivity of the supported catalysts were found to be predominantly arisen from the IrO₂. Supported catalyst showed higher active surface area than the pristine IrO₂ in CV analysis with 85% H₃PO₄ as electrolyte. The MEA performance using Nafion®−115 membrane at 80 °C and atmospheric pressure showed a better performance for IrO₂ loading ≥60 wt.% than the pristine IrO₂ with a normalised current density of 1625 mA cm⁻² @1.8 V for the 60% IrO₂-ATO compared to 1341 mA cm⁻² for the pristine IrO₂ under the same condition. The higher performance of the supported catalysts was mainly attributed to better dispersion of active IrO₂ on electrochemically inactive ATO support material, forming smaller IrO₂ crystallites. A 40 wt.% reduction in the IrO₂ was achieved by utilising the support material.

Investigation of supported IrO2 as electrocatalyst for the oxygen evolution reaction in proton exchange membrane water electrolyser

Indium tin oxide (ITO) was used as a support for IrO2 catalyst in the oxygen evolution reaction. IrO2 nanoparticles were deposited in various loading on commercially available ITO nanoparticle, 17–28 nm in size using the Adam's fusion method. The prepared catalysts were characterised using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The BET surface area of the support (35 m2/g) was 3 times lower than the unsupported IrO2 (112.7 m2/g). The surface area and electronic conductivity of the catalysts were predominantly contributed by the IrO2. The supported catalysts were tested in a membrane electrode assembly (MEA) for electrolyser operation. The 90% IrO2-ITO gave similar performance (1.74 V@1 A/cm2) to that of the unsupported IrO2 (1.73 V@1 A/cm2) in the MEA polarisation test at 80 °C with Nafion 115 membrane which was attributed to a better dispersion of the active IrO2 on the electrochemically inactive ITO support, giving rise to smaller catalyst particle and thereby higher surface area. Large IrO2 particles on the support significantly reduced the electrode performance. A comparison of TiO2 and ITO as support material showed that, 60% IrO2 loading was able to cover the support surface and giving sufficient conductivity to the catalyst.

O interesse socioeducativo (e as dificuldades) de traduzir em português-espanhol

O Projeto que apresentamos insere-se nos estudos do Mestrado em Tradução Especializada dentro da vertente da Saúde e Ciências da Vida; é por isso que, partindo de um texto/suporte que visa promover uma alimentação saudável nas escolas (manual de referência difundido pelos Ministérios da Educação e Ciência e Ministério da Saúde de Portugal), procedemos à tradução (de português para espanhol) de um conteúdo que suscita, nos nossos dias, um grande interesse socioeducativo e cultural. É preciso destacar que o facto de ter nascido e vivido na Venezuela durante doze anos permitiu-me superar com êxito os meus estudos de espanhol na Licenciatura e no referido Mestrado; mas, ao mesmo tempo, tive que me adaptar, enquanto cidadã portuguesa, ao complexo e inacabado processo de ir interiorizando estas duas línguas – português/espanhol – tão próximas e no entanto com sistemas linguísticos bem distintos. Esta evidência encontra a sua maior justificação no grande capítulo dos erros (de forma e de significado) que consegui detetar e analisar graças à ajuda da minha professora orientadora, ao longo deste meu primeiro trabalho académico (texto traduzido para espanhol). Só agora, depois da minha primeira e “ingénua” tradução desse texto/manual, sou capaz de perceber com toda nitidez a dimensão do erro na atividade tradutora, assim como das suas consequências. Além desta importante reflexão, também o facto de elaborar este projeto permitiu-me abordar um aspeto linguístico da língua espanhola que me cativa pessoalmente (no que me diz respeito): o das variantes lexicais do castelhano nos países hispanofalantes. Não duvido em apontar um outro aspeto fundamental: o esforço de ter tido que corrigir minuciosamente e com rigor esta tarefa tradutora (com os seus respetivos comentários tradutológicos) converteu-se numa fonte de múltiplas satisfações pessoais; são aquelas que têm a ver com o cultivo de valores tais como o esforço, o espírito de superação, o exercício da responsabilidade e o (re)conhecimento da honestidade intelectual, entre outros.

Portal de apoio à matemática

Trabalho de projeto de mestrado, Educação (Especialidade de Educação e Tecnologias Digitais), Universidade de Lisboa, Instituto de Educação, 2014

Avaliação da satisfação do utente na comunicação com os profissionais de saúde construção e validação de um instrumento

A satisfação do utente na comunicação com profissionais de saúde é um indicador de qualidade dos serviços ou instituições. Na literatura não encontramos instrumentos padronizados e validados, que avaliem a satisfação do utente na comunicação com os profissionais de saúde. O presente estudo tem como objetivo construir e validar um instrumento para avaliar a satisfação do utente na comunicação com os profissionais de saúde. Desenvolvemos este estudo em três ciclos. Um primeiro, revisão da literatura, para identificar dimensões e itens da comunicação interpessoal na saúde. No segundo ciclo, conduzimos um método de Delphi modificado em três rondas, com recurso à plataforma informática de questionários Survey Monkey, no qual participou um painel de 25 peritos; estabelecemos como critério mínimo de retenção para a ronda seguinte os itens que recebessem 70% do consenso por parte do painel. Após as três rondas, obtivemos um instrumento com seis dimensões comunicacionais (comunicação verbal, comunicação não verbal, empatia, respeito, resolução de problemas e material de apoio), vinte e cinco itens específicos, e mais seis dimensões genéricas, que avaliam cada uma das dimensões. No terceiro ciclo avaliamos as características psicométricas, em termos de sensibilidade, validade do construto e fidelidade, numa amostra de 348 participantes. Os resultados mostram que todas as categorias de resposta estavam representadas em todos os itens. Validade do construto- a análise fatorial identificou uma solução de seis componentes que explicam 71% da variância total. Fiabilidade - os valores da correlação item-total variam entre 0,387 e 0,722, existindo uma correlação positiva moderada a forte. O valor de alfa de Cronbach (α=0,928) indica que a consistência interna é excelente. O instrumento construído apresenta boas propriedades psicométricas. Fica assim disponível uma nova ferramenta para auxiliar na gestão e no processo de planeamento necessários ao incremento da qualidade nos serviços e instituições de saúde.

Desidratação/oxidação seletiva de metanol recorrendo a catalisadores heterogéneos para a obtenção de biocombustíveis (DME e DMM)

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Química e Biológica

Major depressive disorders in the general hospital: how to implement guidelines.

OBJECTIVE: An implementation study that evaluated the impact of previously adopted guidelines on the clinical practice of medical residents was conducted to improve the recognition and treatment of major depressive disorders (MDDs) in hospitalized patients with somatic diseases. METHODS: Guidelines were implemented in two wards (ENT and oncology) using intranet diffusion, interactive sessions with medical residents, and support material. Discharge letters of 337 and 325 patients, before and after the intervention, respectively, were checked for statement of diagnosis or treatment of MDDs and, in a post hoc analysis, for any mention about psychiatric management. RESULTS: No difference was found in the number of diagnosed or treated MDDs before and after the intervention. However, significantly more statements about psychological status (29/309 vs. 13/327) and its management (36/309 vs. 19/327) were observed after the intervention (P<.01). CONCLUSION: The intervention was not successful in improving the management of MDDs. However, a possible effect on general psychological aspects of medical diseases was observed.

Les discours ruraux, urbains et périurbains du cinéma québécois

Ce projet s’intéresse aux représentations que fait le cinéma des territoires et à la manière dont ces représentations reflètent des grands enjeux socio-spatiaux. L’espace cinématographique devient une clé d’entrée pour l’analyse géographique. Cette analyse porte plus particulièrement sur les représentations que fait le cinéma québécois contemporain des espaces urbains, ruraux et périurbains. Les récits et les représentations spatiales qui les composent se positionnent souvent sur les enjeux socio-spatiaux, produits par l’histoire nationale et les processus socioéconomiques. La proposition d’analyser les représentations cinématographiques en lien avec le contexte socioéconomique vise deux principaux objectifs conceptuels. D’une part, elle s’intéresse à une meilleure compréhension du façonnement des discours sur l’espace, en ce qui a trait à leur émergence et leur négociation. D’autre part, l’analyse vise une définition élargie des espaces ruraux, urbains et périurbains contemporains, en révélant la complexité et simultanément, la simplification dont ils font l’objet, ainsi que les enjeux qui leurs sont associés. Il s’agit d’exploiter la cinématographie québécoise comme un outil d’analyse qui permet de dévoiler la diversité des discours socio-spatiaux. Des approches quantitatives et qualitatives d’interprétation des discours sont jumelées pour réaliser une analyse complète. La méthode retenue est l’analyse critique du discours (ACD), qui tient compte des rapports idéologiques et vise à la dénaturalisation du discours. En quelques mots, l’analyse consiste en l’identification de relations entre les représentations spatiales et le contexte socioéconomique duquel elles ont émergé. Le cadre opérationnel est constitué d’un corpus de 50 films québécois réalisés entre 1980-2008, « lus » à l’aide d’une grille de lecture originale et analysés avec des méthodes d’analyse spatiale et statistique, combinées à une interprétation qualitative. L’analyse quantitative révèle que le monde urbain et le monde rural sont souvent mis en opposition. Les films font de Montréal le principal pôle urbain, tandis que le reste du Québec est associé au milieu rural. Influencées par les flux culturels et économiques globaux, les représentations montréalaises suggèrent une ville fragmentée et continuellement en mouvement. En opposition à ces représentations urbaines, les cinéastes envisagent l’espace rural comme étant exempt de travail, axé sur le chez-soi et doté d’un esprit communautaire. Il est suggéré que la ville, toujours en croissance, restreint les possibilités d’un développement communautaire fort. Face à une ville transformée par la globalisation et en perte d’authenticité, une forme de régionalisme est observée. Ce dernier associe un ensemble de valeurs à une communauté ou à un territoire, afin de se distinguer devant des forces globalisantes qui semblent homogénéiser les valeurs. Pourtant, l’analyse quantitative laisse voir des contradictions au sein de chaque entité géographique ou milieu. L’analyse qualitative permet d’approfondir l’interprétation et révèle sept grands discours sur les espaces urbains et ruraux. Sont notamment identifiés des discours sur la contestation de la modernité urbaine, sur la réappropriation du milieu de vie par les citoyens et sur un espace rural parfois brutal. Cette analyse amène à conclure que la diversité des discours s’explique par l’hétérogénéité des pratiques socio-spatiales, qui remettent en question l’idée d’un discours national homogène. Cela témoigne de l’évolution et la négociation des regards que nous posons sur nos espaces. Au final, cette thèse contribue à une meilleure utilisation du matériel cinématographique comme support d’étude géographique en proposant une approche méthodologique claire et originale. Sur un plan conceptuel, elle rappelle la complexité et le dynamisme des représentations territoriales québécoises, ainsi que les stratégies de négociation des cinéastes face aux enjeux socio-spatiaux vécus dans la province.

Investigations on Some Titania Supported Catalysts

Titania is a versatile metal oxide with multiple applications. Titania supported catalysts are reported to be much more active compared to conventional silica or alumina supported ones in some reactions. TiO2 (anatase) having high surface area, with better crystallinity and high onset temperature of rutilation can be prepared by thermal hydrolysis of titanyl sulfate solution under controlled conditions. Calcinations at 350oC for 6 hrs were necessary to crystallize anatase. Method of preparation and percentage of the loaded metal oxides have greater influence on surface area. Drastic decrease in surface area was observed upon rutilation. Rutilation started at different temperatures depending on the metal oxide and the method of preparation. TiO2 should be characterized with high surface area, phase purity and high onset temperature of rutilation.Which should be well above the optimum temperature of a designated reaction in which it is employed as a catalyst. Variation in physical properties, depending upon the method of preparation is greater in TiO2 supported catalysts. Methanation activity was found to be highly dependent on nickel concentration present on the surface of the pellets. The methanation activity is strongly influenced by support material. The rate and turn over frequency of methanation and toluene oxidation activity of these catalysts are also equally important from an industrial point of view.

Studies on immobilization of Bacteria

Cell immnhilizatinn technology in a rapidly expanding arna in the endeavour of microbial fnrmentatiwn.During the lnmt 15 years anveral prnceafinn have been developed and more are in developmental atage of approaching commercial utilizatinn.In the present programme it was planned to develop an optimized process for the innobilization of alpha amylase producing Bacillus polymyxa (CBTB 25) an isolate obtained from Cochin University campus primarily for the production of alpha-amylase.Optimal concentration of support material that attributaa stability and maximal activity to the immobilized cell beads was determined using different concentrations of sodium aliginate as support and estimation of amylase production.An overeall assessment of the data obtained for the various studies conducted denotes that immobilized cells synthesize alpha-amylase at comparable rates with free cells and produce reducing sugara at a higher level than free cells.Results indicated that both phosphate and citrate buffers could be used for disrupting the immobilized beads since they enforced maximal release of cells through leaching from the beads within one hour.On comparative analysis it was observed that immobilized cells could synthesize alpha amylase at similar levels with free cells of B.polymyxa.On Co-immobilization of B.Polymyxa with S.cerevisiae,the co-immobilizate beads could effeciently convert starch directly to ethanol with a yield of 14.8% at 1 : 2 ratio.

Technical report template, links to additonal writing resources

A set of support material to be used when preparing a technical report. Includes report template, and links to other supporting materials specific to the University. Finally link to 2015 COMP1205 technical report assignment specification and allocations http://www.edshare.soton.ac.uk/14582/

Fronteiras da nova economia institucional

These papers deal with some main topics in new institutional economics. I make a survey of the literature, considering the contributions presented by Buchanan, Tullock, Coase, Olson and North to modern approaches to political economy. In fact, the first article is very simple. It should be used as support material in economics seminars at undergraduated level. The second one is an academic paper and deals basically with the contributions of public choice theory to the political understanding.

Avaliação de bactérias nitrificantes em filtros biológicos submersos aerados

This study investigates a new treatment system of wastewater by anaerobic and aerobic biological filters for nitrogen modification. The main objective of this study was evaluate, on a pilot scale, quantitatively and qualitatively the bacterian nitrifying community in a experimental sewage treatment system made by aerobics biological filters in series, in search of figure out the dynamic of nitrogen modification process. It was collected and laboratorial analysed microbiologically, regarding NMP of Nitrosomonas e Nitrobacter, and physical-chemically considering nitrogen sequence. We conclude that: the association in aerobic biological filters under nutrition controlled conditions and oxygen level allows the appearance of bacterian community responsible for the nitrogen modification; the method used, despite its limitations, provided the selection of autotrophic nitrifying microorganisms, allowing the identification of Nitrosomonas and Nitrobacter; the flow direction tested in the experimental unit did not affect the nitrifying bacterial community, certainly because they were kept drowned and did not occur flow speed that could breake the formed biomass; the nitrification process happened in aerated biological filters in all phases of the research, comproved by microbiological tests; in the third phase of the research the increase of the oxygen rate was significant for the nitrificant bacterian community in the aerate biological filters, allowing its growth, occurring relation between the efficiency of nitrification system and the quantity of organisms responsible for this process; the conduit used in aerated biological filters showed satisfactory performance support material to the nitrifying bacteria development