Perovskite Solar Cells: Developing a simple, fast and low-cost Fabrication Technology

Solar energy is the most abundant renewable resource and is regarded as the most promising for the sustainability of our society. Perovskites are a class of semiconductor materials with unique properties since they allow films fabrication with high electronic quality using non-vacuum solution techniques. Therefore, such materials are interesting for a wide range of opto-electronic applications. Perovskites allow rapid, simple and low-cost solar cell manufacturing, being nowadays considered the most promising material to compete with silicon in photovoltaics technology. However, the production of homogeneous MAPbI3 films by Spin Coating is challenging, as it requires precise control of several factors that influence the films’ properties. In this work, the influence of the main deposition parameters on the MAPbI3 thin films manufacture was studied to find the best processing conditions that enable obtaining films as homogeneous and uniform as possible. This allowed attaining MAPbI3 polycrystalline films with state-of-art quality, having grain sizes between 3 and 13 μm and UV-Visible absorption of 85-90 %. The remaining layers (i.e. selective contacts) of the Perovskite cell structure were investigated as well, allowing the fabrication of sets of full solar cells with a maximum VOC of 0.77 V and JSC of 7.65 mA.cm-2

History, Nation and Politics: the Middle Ages in Modern Portugal (1890-1947)

Nas últimas décadas, o estudo da historiografia, da memória histórica e dos usos do passado tem suscitado cada vez maior atenção junto dos meios académicos. O medievalismo em particular, comummente entendido como a representação ou o uso da Idade Média no período pós-medieval, assume aqui um papel significativo, dada a importância da época medieval na cultura histórica romântica e nos processos de construção das identidades nacionais desde o século XIX. No contexto académico português, porém, o medievalismo foi ainda escassamente analisado, faltando um estudo que abranja as suas várias dimensões, da historiografia às políticas de memória. Esta dissertação pretende colmatar esta lacuna, ao explorar as várias representações da Idade Média em Portugal entre o final do século XIX e a primeira metade do século XX. Focando três grandes temas – escrita da história, património artístico e comemorações históricas – iremos demonstrar como certos conceitos, instituições, figuras, eventos e obras da história medieval portuguesa foram narrados, retrabalhados e celebrados, à luz dos discursos decadentistas sobre a nação e sobre o mundo ocidental e da evolução política do país neste período. Estudos internacionais sobre este tema permitirão a realização de exercícios comparativos, bem como considerar a dimensão transnacional do medievalismo português, inserido nas grandes correntes culturais e ideologias políticas que influenciaram as várias representações da época medieval neste período. No final, iremos verificar como uma visão essencialmente romântica da história portuguesa persistiu ao longo de grande parte do século XX, ao representar dicotomicamente a Idade Média de forma positiva em comparação com uma Modernidade identificada com declínio civilizacional e espiritual.In recent decades, the study of historiography, historical memory and the uses of the past has become a subject of increasing attention in academic circles. Medievalism in particular, commonly understood as the representation or use of the Middle Ages in the post-medieval period, assumes here an significant role, given the importance of the medieval epoch in Romantic historical culture and in nation-building processes since the nineteenth century. However, medievalism has still been scarcely analysed in the Portuguese context, lacking a study that encompasses its multiple dimensions, from historiography to politics of memory. This dissertation aims to fulfil this gap, by exploring the various representations of the Middle Ages in Portugal between the late nineteenth and the first half of the twentieth century. Focusing on three major topics – writing of history, artistic heritage and historical commemorations –, we will demonstrate how certain concepts, institutions, figures, events and works of Portuguese medieval history were narrated, reworked and celebrated, in the light of decadentist discourses about the nation and the Western world and of Portugal‘s political evolution in this period. International research on the topic will allow the making of comparative analyses and the understanding of the transnational dimension of Portuguese medievalism, inserted in the major cultural trends and political ideologies that influenced the various depictions of the medieval epoch in this period. In the end, we will show that an essentially Romantic view of Portuguese history persisted through the twentieth century, dichotomically presenting the Middle Ages in a positive light in comparison with a Modernity identified with civilizational and spiritual decline

Walking towards the “hidden” role of dirigent proteins in Vitis vinifera secondary metabolism

Grapevine is one of the most cultivated fruit crop worldwide with Vitis vinifera being the species with the highest economical importance due to the high quality standards of its berries. Nonetheless, it is also the most susceptible Vitis species to fungal pathogens. Among others, relevant fungal diseases currently threatening grapevine cultures are powdery mildew, caused by Erysiphe necator, and esca, a disease complex comprised of several fungi in which Phaeomoniella chlamydospora and Phaeoacremonium aleophilum participate.(...)Fundação para a Ciência e a Tecnologi

Development of the Structure of a long Endurance Electric UAV

The goal of this project is to design and create the structure of a long endurance unmanned aerial vehicle (UAV) using solar power. The design’s main requirement was the creation of a low weight structure to handle diverse missions with a 1 Kilogram of payload. The UAV structure was divided in three parts: fuselage, empennages and empennage support, designed using CATIA® to verify interfaces and to study the positioning of the systems access and functionality. Because the main target is to build a low weight structure, the carbon fibre and wood were chosen for the fuselage, empennage support and tail, respectively. Two methods of structure analyses were used to design the composite structures, one a numerical analysis and the other the finite element method from ANSYS®. The UAV structure was manufactured in two phases. First was the composite structure using the hand lay-up and vacuum bagging method. And the second was the empennage structure using balsa wood construction. When the UAV structure was finished, a structural test was carried out to verify both analysis and manufacturing methods.Este trabalho tem como objetivo o desenvolvimento e criação da estrutura de um avião não tripulado (UAV) de longa autonomia movido a energia solar. O desenvolvimento teve como principal objetivo a criação de uma estrutura suficientemente leve, para poder efetuar diversas missões com uma carga útil de 1 Kg. A estrutura do UAV foi dividida em três partes, as quais compreendem: a fuselagem, empenagens e suporte de empenagens. Estas foram projetadas utilizando o CATIA® para verificar as interfaces e para estudar posições de acesso e funcionalidade. Dado que o objetivo principal é de uma estrutura leve, foi utilizado como material a fibra de carbono para a fuselagem e suporte de empenagens e a madeira para as empenagens. A estrutura em compósito foi dimensionada utilizando dois métodos: método numérico e método computacional, com recurso ao software de elementos finitos ANSYS®. A produção da estrutura do UAV foi executada em duas fases. A primeira foi a estrutura em compósito utilizando o método de hand lay-up e vacuum baggin method. E a segunda as estruturas das empenagens, utilizando os métodos de construção em madeira. Produzida toda a estrutura, foram efetuados testes estruturais para verificação de todos os métodos de construção bem como da análise estrutural

State aid & competition: The TAP case

This thesis aims to provide an insight into the entire process of State aid. Using the recent measure of State aid approved by the European Commission to give support to the Portuguese airline company TAP, we explore how the process of State aid is conducted, what are its aims, and how it affects the market in which the firm on the receiving end of the State Aid operation is inserted, from the perspective of both firms and consumers alike. For this end, we work with flight data gathered directly from official sources such as Google Flights and the official website the airline company easyJet. Using the data collected, we assessed the Herfindahl-Hirschman Index (HHI) in order to measure the market concentration of the markets in question. Furthermore, we discuss the general aims of the applicable policies as well as their implementation and consequences. We find that the most important policies succeed in their main objectives of mitigating the distortions of market competition caused by the application of a State Aid operation.Esta tese tem como principal objetivo providenciar uma melhor compreensão de todo o processo de Ajudas de Estado. Usando com exemplo a recente operação de Ajuda de Estado aprovada pela Comissão Europeia com fim de dar ajudar a companhia aérea portuguesa TAP, exploramos como o processo de Ajudas de Estado é executado, quais os seus objetivos, e a maneira como afeta o mercado no qual a empresa que recebe a Ajuda de Estado esta inserida, tanto das perspetivas das empresas e dos consumidores. Para este fim, trabalhamos com dados de voos recolhidos diretamente de fonte oficiais como Google Flights e o website oficial da companhia aérea easyJet. Através dos dados recolhidos, calculamos o Índice Herfindahl-Hirschman (HHI) com o objetivo de medir o nível de concentração de mercado dos mercados em questão. Continuando, discutimos os objetivos gerais das medidas aplicadas assim como a sua implementação e consequências. Concluímos que as medidas mais importantes são bem-sucedidas nos seus principais objetivos de restringir as distorções de competição de mercado causadas pela aplicação da operação de Ajudas de Estado

Unveiling the mating system and genetic variability in the yeast Kwoniella mangroviensis using molecular approaches

Dissertação para obtenção do Grau de Mestre em Genética Molecular e BiomedicinaIn fungi, sexual reproduction is orchestrated by genomic regions known as mating type loci (MAT), which can be defined by two physically unlinked sex determining regions (tetrapolar mating system) or a single locus (bipolar system). Kwoniella mangroviensis is a saprobic basidiomycetous yeast, belonging to the Kwoniella clade of the order Tremellales, which was described as possessing a bipolar mating-system, similar to the related pathogenic species Cryptococcus neoformans and Cryptococcus gattii of the sister Filobasidiella clade. Studies aimed at elucidating the evolution of the MAT locus of these two Cryptococcus species of clinical importance, targeted several related saprobic species in the Kwoniella and Filobasidiella clades. An evolutionary model ensuing from those studies suggests that the tetrapolar mating-systems found in most species are ancestral and gave rise to the bipolar mating-system of C. neoformans by chromosomal rearrangements and fusion events. The present study comprised strains from the original work describing K. mangroviensis, as well as additional isolates from plant substrates in Europe and Africa. A multilocus sequence typing approach revealed genetic variability among those strains and led to the identification of two novel species closely related to K. mangroviensis: Kwoniella sp. A and Kwoniella sp. B. The mating system of K. mangroviensis and sibling species was further explored by a genetic approach based on sequencing of two MAT genes: STE20 and the divergently transcribed genes SXI1 and SXI2. The results obtained demonstrated tetrapolar mating systems in K. mangroviensis, as well as in Kwoniella sp. A and Kwoniella sp. B. Additionally, the MAT locus structure of K. mangroviensis was unveiled by sequencing a 43 kb genomic region containing the STE20 gene. Twelve genes also present in the MAT loci of related species were identified, and full synteny was found between K. mangroviensis and Cryptococcus heveanensis, a distant member of the Kwoniella clade. These findings provided novel insights into the evolution of MAT loci in basidiomycetous yeasts in the Tremellales.Fundação para a Ciência e Tecnologia - PTDC/BIA-MIC/113051/200

The talent attractiveness of the city of London after Brexit

Talent Attraction of the City of London was long hailed as a main driver for the City´s success in the world stage, being also noted to be the key for its adaptability when dealing with the 2008 crisis. In a post-Brexit UK, the City faces new challenges leading us to question how Brexit seems to be impacting the City´s talent attractiveness. This is particularly relevant as Brexit brought an end to the free movement of people from the EU, which for long facilitated the migration inflows of highly skilled talent. With this in mind, we have collected the perception of 159 people interested in working in the financial industry which has shown a grim image for the City´s attractiveness. Other than the Quality-of-life factors and the factor internationally competitive salary, all other factors of talent attraction have suffered with Brexit as evidenced by the City’s lower ratings compared to other big financial centres in Europe. Findings additionally show that this is reversible if the UK were to return to the EU. However, as it stands, the findings from the t test and the OLS regression show the Quality-of-life factors to be paramount for the current talent attractiveness of the City.A atração de Talento da City de Londres foi há muito aclamada como o principal motor do seu sucesso no palco mundial, tendo sido também indicada como a chave para a sua adaptabilidade durante a crise de 2008. Num Reino Unido pós-Brexit, a City enfrenta novos desafios que nos levaram a questionar que impacto o Brexit parece estar a ter na atratividade do talento da City. Isto é particularmente relevante uma vez que o Brexit trouxe um fim à livre circulação de pessoas da UE, o que durante muito tempo facilitou os fluxos migratórios de talentos altamente qualificados. Com isto em mente, recolhemos a perceção de 159 pessoas interessadas em trabalhar na indústria financeira, o que mostrou uma imagem desanimadora da atratividade da City. Para além dos fatores Qualidade-de-vida e do fator Salário-internacionalmente-competitivo, todos os outros fatores de atração de talentos sofreram com o Brexit, tal como indicam as classificações mais baixas da City por comparação com outros grandes centros financeiros na Europa. Os resultados mostram ainda que isto é reversível se o Reino Unido regressar à UE. No entanto, a manter-se a situação, os fatores de qualidade-de-vida parecem ser críticos para a atual atração de talentos da City

New simple Lie algebras over fields of characteristic 2

New simple Lie algebras over fields of characteristic