A comparison of theoretical Mg VI emission line strengths with active-region observations from SERTS

R-matrix calculations of electron impact excitation rates in N-like Mg VI are used to derive theoretical electron-density-sensitive emission line ratios involving 2s²2p³ - 2s2p⁴ transitions in the 269-403 Å wavelength range. A comparison of these with observations of a solar active region, obtained during the 1989 flight of the Solar EUV Rocket Telescope and Spectrograph (SERTS), reveals good agreement between theory and observation for the 2s²2p^{3 4}S - 2s2p ^{4 4}p transitions at 399.28, 400.67, and 403.30 Å, and the 2s²2p^{3 2}p - 2s2p^{4 2}D lines at 387.77 and 387.97 Å. However, intensities for the other lines attributed to Mg VI in this spectrum by various authors do not match the present theoretical predictions. We argue that these discrepancies are not due to errors in the adopted atomic data, as previously suggested, but rather to observational uncertainties or mis-identifications. Some of the features previously identified as Mg VI lines in the SERTS spectrum, such as 291.36 and 293.15 Å, are judged to be noise, while others (including 349.16 Å) appear to be blended.

Heat Activated Prestressing of Shape Memory Alloys for Active Confinement of Concrete Sections

This paper presents the results from the experimental investigation on heat activated prestressing of Shape Memory Alloy (SMA) wires for active confinement of concrete sections. Active confinement of concrete is found to be much more effective than passive confinement which becomes effective only when the concrete starts to dilate. Active confinement achieved using conventional prestressing techniques often faces many obstacles due to practical limitations. A class of smart materials that has recently drawn attention in civil engineering is the super elastic SMA which has the ability to undergo reversible hysteretic shape change known as the shape memory effect. The shape memory effect of SMAs can be utilized to develop a convenient prestressing technique for active confinement of concrete sections.
In this study a series of experimental tests are conducted to study Heat Activated Prestress (HAP) in SMAs. Three different types of tests are conducted with different loading protocol to determine parameters such as HAP, residual strain after heating and range of strain that can be used for effective active confinement after HAP. Test results show a maximum HAP of about 500 MPa can be achieved after heating and approximately 450MPa is retained at 25oC in specimens pre-strained by 6%. A substantial amount of strain recovery upon unloading and after heating the SMA wires is recorded. About 2.5% elastic strain recovery upon unloading from 6% strain level is observed. In the specimen pre-strained by 6%, a total of 4% strain is recovered when unloaded after heating. A strain range of 3% is found available for effective confinement after HAP. Test results demonstrate that SMAs have unique features that can be intelligently employed in many civil engineering applications including active confinement of concrete sections.

Determinants of uptake and maintenance of active commuting to school

The objective was to identify determinants of uptake and maintenance of active school travel (AST) over 4 years in children aged 9 at baseline. Data from wave 1 (n=8502) and 2 (n=7479) of the Growing Up in Ireland study were analysed. At 9- and 13-years 25% and 20% engaged in AST. Children were more likely to maintain or take-up AST if they lived in an urban area. Change in distance to school influenced both maintenance and adoption of AST, with a negative impact seen for increased distance between 9 and 13 years and a positive impact seen for decreased distance. Some factors which predict uptake and maintenance of AST are modifiable and can inform intervention development.

Prevention of falls in the elderly in the home: promoting active ageing

Objective: To determine the frequency of falls and identify risk factors in the homes of the elderly under the Home Care Service of a village in Alentejo (Portugal). Method: Exploratory, descriptive study. The target group were elderly persons under the Home Care Service (23). The questionnaire consists of open and closed questions, and was based on the Jefferson Area Board for Aging Safety in the Home Assessment; Instrument to Assess the Risk of Falls and Adaptations to Prevent Falls at Home. Results: Of the 23 seniors, 13 were men; the mean age was 85; 10 widowers; 11 live alone; 12 cannot read or write; 17 have experienced falls, loss of balance being the main cause. They report changes in vision (21), hearing (14) and rheumatic diseases (14); hypertension (19); they use 4 or more drugs on a daily basis (16). Conclusion: The physiological changes associated with ageing may increase the risk of falls. Due to the consequences, it is a priority field in community intervention.

Prevention of falls in the elderly in the home: promoting active ageing

To determine the frequency of falls and identify risk factors in the homes of the elderly under the Home Care Service of a village in Alentejo (Portugal). Method: Exploratory, descriptive study. The target group were elderly persons under the Home Care Service (23). The questionnaire consists of open and closed questions, and was based on the Jefferson Area Board for Aging Safety in the Home Assessment; Instrument to Assess the Risk of Falls and Adaptations to Prevent Falls at Home. Results: Of the 23 seniors, 13 were men; the mean age was 85; 10 widowers; 11 live alone; 12 cannot read or write; 17 have experienced falls, loss of balance being the main cause. They report changes in vision (21), hearing (14) and rheumatic diseases (14); hypertension (19); they use 4 or more drugs on a daily basis (16). Conclusion: The physiological changes associated with ageing may increase the risk of falls. Due to the consequences, it is a priority field in community intervention.

Active corrosion protection of AA2024 by sol-gel coatings with corrosion inhibitors

A indústria aeronáutica utiliza ligas de alumínio de alta resistência para o fabrico dos elementos estruturais dos aviões. As ligas usadas possuem excelentes propriedades mecânicas mas apresentam simultaneamente uma grande tendência para a corrosão. Por esta razão essas ligas necessitam de protecção anticorrosiva eficaz para poderem ser utilizadas com segurança. Até à data, os sistemas anticorrosivos mais eficazes para ligas de alumínio contêm crómio hexavalente na sua composição, sejam pré-tratamentos, camadas de conversão ou pigmentos anticorrosivos. O reconhecimento dos efeitos carcinogénicos do crómio hexavalente levou ao aparecimento de legislação banindo o uso desta forma de crómio pela indústria. Esta decisão trouxe a necessidade de encontrar alternativas ambientalmente inócuas mas igualmente eficazes. O principal objectivo do presente trabalho é o desenvolvimento de prétratamentos anticorrosivos activos para a liga de alumínio 2024, baseados em revestimentos híbridos produzidos pelo método sol-gel. Estes revestimentos deverão possuir boa aderência ao substrato metálico, boas propriedades barreira e capacidade anticorrosiva activa. A protecção activa pode ser alcançada através da incorporação de inibidores anticorrosivos no prétratamento. O objectivo foi atingido através de uma sucessão de etapas. Primeiro investigou-se em detalhe a corrosão localizada (por picada) da liga de alumínio 2024. Os resultados obtidos permitiram uma melhor compreensão da susceptibilidade desta liga a processos de corrosão localizada. Estudaram-se também vários possíveis inibidores de corrosão usando técnicas electroquímicas e microestruturais. Numa segunda etapa desenvolveram-se revestimentos anticorrosivos híbridos orgânico-inorgânico baseados no método sol-gel. Compostos derivados de titania e zirconia foram combinados com siloxanos organofuncionais a fim de obter-se boa aderência entre o revestimento e o substrato metálico assim como boas propriedades barreira. Testes industriais mostraram que estes novos revestimentos são compatíveis com os esquemas de pintura convencionais actualmente em uso. A estabilidade e o prazo de validade das formulações foram optimizados modificando a temperatura de armazenamento e a quantidade de água usada durante a síntese. As formulações sol-gel foram dopadas com os inibidores seleccionados durante a primeira etapa e as propriedades anticorrosivas passivas e activas dos revestimentos obtidos foram estudadas numa terceira etapa do trabalho. Os resultados comprovam a influência dos inibidores nas propriedades anticorrosivas dos revestimentos sol-gel. Em alguns casos a acção activa dos inibidores combinou-se com a protecção passiva dada pelo revestimento mas noutros casos terá ocorrido interacção química entre o inibidor e a matriz de sol-gel, de onde resultou a perda de propriedades protectoras do sistema combinado. Atendendo aos problemas provocados pela adição directa dos inibidores na formulação sol-gel procurou-se, numa quarta etapa, formas alternativas de incorporação. Na primeira, produziu-se uma camada de titania nanoporosa na superfície da liga metálica que serviu de reservatório para os inibidores. O revestimento sol-gel foi aplicado por cima da camada nanoporosa. Os inibidores armazenados nos poros actuam quando o substrato fica exposto ao ambiente agressivo. Numa segunda, os inibidores foram armazenados em nano-reservatórios de sílica ou em nanoargilas (halloysite), os quais foram revestidos por polielectrólitos montados camada a camada. A terceira alternativa consistiu no uso de nano-fios de molibdato de cério amorfo como inibidores anticorrosivos nanoparticulados. Os nano-reservatórios foram incorporados durante a síntese do sol-gel. Qualquer das abordagens permitiu eliminar o efeito negativo do inibidor sobre a estabilidade da matriz do sol-gel. Os revestimentos sol-gel desenvolvidos neste trabalho apresentaram protecção anticorrosiva activa e capacidade de auto-reparação. Os resultados obtidos mostraram o elevado potencial destes revestimentos para a protecção anticorrosiva da liga de alumínio 2024.

Educação para a diversidade e desenvolvimento fonológico na infância

O presente trabalho analisa o papel de uma abordagem plural de sensibilização à diversidade linguística na promoção da consciência fonológica de crianças em idade pré-escolar. Para o efeito, acompanha o percurso de desenvolvimento da consciência fonológica de um grupo de vinte e uma crianças, com idades compreendidas entre os 3 e os 6 anos, que participaram num projeto de sensibilização à diversidade linguística, intitulado «Uma viagem pelo mundo das línguas e dos sons». Abraçando um paradigma misto de investigação, o estudo recorreu a procedimentos quantitativos e qualitativos de recolha e análise de dados: com o objetivo de avaliar o desenvolvimento fonológico das crianças, recolheram-se e analisaram-se estatisticamente dados provenientes de testes de consciência fonológica, que foram aplicados a um grupo experimental e a um grupo de controlo, antes e após a realização do projeto de intervenção; de forma a compreender como se processou o desenvolvimento da consciência fonológica das crianças, foram feitos registos áudio e vídeo das sete sessões do projeto que foram, posteriormente, transcritos e submetidos a uma análise de conteúdo. Os resultados da análise revelam que, ao contrário das crianças do grupo de controlo, as crianças que participaram no projeto de intervenção desenvolveram a sua consciência fonológica de forma significativa, sobretudo no que se refere às capacidades de manipulação e segmentação fonémicas. Esse desenvolvimento foi mais visível em crianças mais velhas (5-6 anos) do que em crianças mais novas (3-4 anos) e parece ter sido promovido pelas atividades de sensibilização à diversidade linguística em que as crianças participaram. Em particular, as atividades de análise e de comparação inter e intralinguística despertaram a curiosidade das crianças em relação ao objeto-língua e estimularam uma vontade para brincar com os sons e com as letras, o que possibilitou o desenvolvimento de uma consciência mais explícita das unidades do oral e a descoberta do princípio alfabético. Estes resultados atestam a importância da integração curricular de abordagens plurais na educação da infância, no âmbito de uma educação global e integrada, capaz de atender às diversidades das crianças, promover atitudes positivas face à alteridade e assegurar o desenvolvimento de competências metalinguísticas, indispensáveis para uma aprendizagem ao longo da vida e para uma participação ativa em sociedades multilingues e multiculturais.

Extension of electrochemically active sites in SOFCs and SOECs

Solid oxide fuel (SOFCs) and electrolyzer (SOECs) cells have been promoted as promising technologies for the stabilization of fuel supply and usage in future green energy systems. SOFCs are devices that produce electricity by the oxidation of hydrogen or hydrocarbon fuels with high efficiency. Conversely, SOECs can offer the reverse reaction, where synthetic fuels can be generated by the input of renewable electricity. Due to this similar but inverse nature of SOFCs and SOECs, these devices have traditionally been constructed from comparable materials. Nonetheless, several limitations have hindered the entry of SOFCs and SOECs into the marketplace. One of the most debilitating is associated with chemical interreactions between cell components that can lead to poor longevities at high working temperatures and/or depleted electrochemcial performance. Normally such interreactions are countered by the introduction of thin, purely ionic conducting, buffer layers between the electrode and electrolyte interface. The objective of this thesis is to assess if possible improvements in electrode kinetics can also be obtained by modifying the transport properties of these buffer layers by the introduction of multivalent cations. The introduction of minor electronic conductivity in the surface of the electrolyte material has previously been shown to radically enhance the electrochemically active area for oxygen exchange, reducing polarization resistance losses. Hence, the current thesis aims to extend this knowledge to tailor a bi-functional buffer layer that can prevent chemical interreaction while also enhancing electrode kinetics.The thesis selects a typical scenario of an yttria stabilized zirconia electrolyte combined with a lanthanide containing oxygen electrode. Gadolinium, terbium and praseodymium doped cerium oxide materials have been investigated as potential buffer layers. The mixed ionic electronic conducting (MIEC) properties of the doped-cerium materials have been analyzed and collated. A detailed analysis is further presented of the impact of the buffer layers on the kinetics of the oxygen electrode in SOFC and SOEC devices. Special focus is made to assess for potential links between the transport properties of the buffer layer and subsequent electrode performance. The work also evaluates the electrochemical performance of different K2NiF4 structure cathodes deposited onto a peak performing Pr doped-cerium buffer layer, the influence of buffer layer thickness and the Pr content of the ceria buffer layer. It is shown that dramatic increases in electrode performance can be obtained by the introduction of MIEC buffer layers, where the best performances are shown to be offered by buffer layers of highest ambipolar conductivity. These buffer layers are also shown to continue to offer the bifunctional role to protect from unwanted chemical interactions at the electrode/electrolyte interface.

Micro/nanoreservoirs for controlled release of active species in smart functional coatings

This work reports one possible way to develop new functional coatings used to increase the life time of metallic structures. The functionalities selected and attributed to model coatings in the frame of this work were corrosion protection, self-sensing and prevention of fouling (antifouling). The way used to confer those functionalities to coatings was based on the encapsulation of active compounds (corrosion inhibitors, pH indicators and biocides) in micro and nanocontainers followed by their incorporation into the coating matrices. To confer active corrosion protection, one corrosion inhibitor (2-mercaptobenzothiazole, MBT) was encapsulated in two different containers, firstly in silica nanocapsules (SiNC) and in polyurea microcapsules (PU-MC). The incorporation of both containers in different models coatings shows a significant improvement in the corrosion protection of aluminum alloy 2024 (AA2024). Following the same approach, SiNC and PU-MC were also used for the encapsulation of phenolphthalein (one well known pH indicator) to introduce sensing properties in polymeric coatings. SiNC and PU-MC containing phenolphthalein acted as corrosion sensor, showing a pink coloration due to the beginning of cathodic reaction, resulting in a pH increase identified by those capsules. Their sensing performance was proved in suspension and when integrated in coatings for aluminium alloy 2024 and magnesium alloy AZ31. In a similar way, the biocide activity (antifouling) was assigned to two polymeric matrices using SiNC for encapsulation of one biocide (Dichloro-2-octyl-2H-isothiazol-3-one, DCOIT) and also SiNC-MBT was tested as biocide. The antifouling activity of those two encapsulated compounds was assessed through inhibition and consequent decrease in the bioluminescence of modified E. coli. That effect was verified in suspension and when incorporated in coatings for AISI 1008 carbon steel. The developed micro and nanocontainers presented the desired performance, allowing the introduction of new functionalities to model coatings, showing potential to be used as functional additives in the next generation of multifunctional coatings.

Finit element model for active control of adaptive laminated structures

A finite element formulation for active vibration control of thin plate laminated structures with integrated piezoelectric layers, acting as sensors and actuators in presented. The finite element model is a nonconforming single layer triangular plate/shell element with 18 degrees of freedom for the generalized displacements and one electrical potential degree of freedom for each piezoelectric element layer, and is based on the kirchhoff classical laminated theory. To achieve a mechanism of active control of the structure dynamic response, a feedback control algorithm is used, coupling the sensor and active piezoelectric layers, and Newmark method is used to calculate yhe dynamic response of the laminated structures. The model is applied in the solution of several illustrative cases, and the results are presented and discussed.

Construction d'une communauté apprenante dans le contexte de la réforme le cas d'un récit d'apprentissage d'une équipe-école au Brésil

Cette thèse résulte d'une recherche qualitative qui s'inscrit dans le domaine de la recherche-action. L'origine de cette étude vient d'un projet pilote exploratoire réalisé auprès d'enseignants dans une école secondaire du Brésil. Les problèmes de transfert quant à la formation et à l'appropriation de la réforme en éducation nous ont amenée à développer une démarche particulière.Cette démarche privilégie l'usage de l'apprentissage dans l'action selon deux approches complémentaires: l'approche du codéveloppement professionnel (Payette et Champagne, 2000) et l'approche normative de l'organisation apprenante (Senge et al ., 2000) dans la construction d'une communauté apprenante dans un contexte de réforme scolaire. L'approche du codéveloppement met l'accent sur le partage des expériences, sur la réflexion individuelle et de groupe, sur les interactions structurées entre professionnels expérimentés. Elle vise à élargir les capacités d'action et de réflexion de chaque membre du groupe. L'approche normative de l'organisation apprenante suppose que l'apprentissage, comme activité collective, se produit sous certaines conditions ou certaines circonstances. Le rôle des responsables de l'organisation dans cette perspective est de créer les conditions essentielles afin que se produise l'apprentissage. L'objectif de cette recherche porte sur l'évolution du développement de la communauté d'apprentissage dans une équipe-école au Brésil. Une communauté apprenante est un groupe de personnes qui adopte une approche active, collaborative, orientée vers l'apprentissage, lequel favorise la croissance et le développement des individus pour résoudre les problèmes, les mystères et les incertitudes liées à l'enseignement et à l'apprentissage (Mitchell et Sackney, 2000). Grâce à une collecte de données articulant l'observation participante, les questions et les exercices réflexifs, nous avons pu faire émerger les données. L'analyse des données a été guidée par le modèle interactif de Huberman et Miles (1991) et de la théorie ancrée de Glaser et Strauss (1967). Le récit d'apprentissage (Roth et Kleiner, 2000), une approche qui préconise l'entrevue semi-structurée comme principal instrument de collecte des données, a permis de décrire et de comprendre l'évolution du processus et les impacts produits par les stratégies d'intervention.Cette approche se caractérise par une nouvelle façon de présenter et de raconter un changement à travers les mots et les voix des personnes impliquées. Elle est composé de sept étapes: vie réelle, sessions de planification, collecte de données, distillation, écriture et production, validité et dissémination. À la lumière des résultats, nous avons pu dégager que les stratégies d'intervention ont eu des effets significatifs sur le développement personnel, professionnel et organisationnel, que la réforme de l'éducation, dans ce cas, passe premièrement par un processus de développement individuel et de groupe et par une transformation d'une équipe-école en une communauté apprenante.Cette communauté s'avère un véritable processus dynamique, qui se construit à l'intérieur d'un espace scolaire, à partir d'échanges d'expérience et à l'aide de stratégies particulières.

Effects of active pharmaceutical ingredients in mussel mytilus galloprovincialis

More than 3000 types of active pharmaceutical ingredients (APIs) are applied in Human and veterinary medicine practice. These compounds are considered an emergent class of environmental contaminants with the ability to cause damage and unexpected effects to aquatic organisms, namely in species of high commercial value. APIs are ubiquitous in the environment being frequently detected in influents and effluents of waste water treatment plants (WWTPs), surface waters and more distressingly in the public tap water in concentrations ranging from ng to μg.L-1. Considering these premises, the present thesis focused on APIs detection in the Arade river water, the impact of summer period in APIs’ concentration alterations applying the passive sampler device, POCIS (polar organic compound integrative sampler), as well as, the assessment of the effects caused by non-steroidal anti-inflammatory drugs (NSAID) ibuprofen (IBU) and diclofenac (DCF) and antidepressant selective serotonin reuptake inhibitor (SSRI) fluoxetine as single and mixture exposures along with a classical contaminant copper (Cu) on a non-target species, mussel Mytilus galloprovincialis. For this purpose, a multibiomarker approach was applied namely including biomarkers of oxidative stress (antioxidant enzymes activities of superoxide dismutase – SOD, catalase – CAT, glutathione reductase – GR and Phase II glutathione-S-transferase), damage - lipid peroxidation (LPO), neurotoxic effects (through the activity of acetylcholinesterase enzyme - AChE) and endocrine disruption (through vitellogenin-like proteins measurement applying the indirect method of alkali-labile phosphate - ALP) after exposure of mussel species’ to selected APIs at environmental relevant concentrations. The main results highlighted the occurrence of 19 APIs in the river Arade from several distinct therapeutic classes. Stimulant caffeine, antiasthmatic theophylline, NSAID ibuprofen and analgesic paracetamol presented the highest concentrations. Summer impact was inconclusive due to each API transient concentration in each month. The multibiomarker results revealed distinct responses towards each selected API (as single exposure or as mixtures) that were tissue and time dependent. Several multistressor interactions were proposed for each biomarker. The results also revealed APIs potential to induce oxidative stress, LPO, neurotoxicity and endocrine disruption even at extremely low concentrations on a species extremely vulnerable to APIs presence highlighting the urgency on the development of methodologies able to prevent its entrance in the aquatic environment.