Super-Gaussian conical refraction beam

We demonstrate the transformation of Gaussian input beams into super-Gaussian beams with a quasi flat-top transverse profile by means of the conical refraction phenomenon by adjusting the ratio between the ring radius and the waist radius of the input beam to 0.445. We discuss the beam propagation of the super-Gaussian beam and show that it has a confocal parameter three times larger than the one that would be obtained from a Gaussian beam. The experiments performed with a KGd(WO4)2 biaxial crystal are in good agreement with the theoretical predictions. © 2014 Optical Society of America.

Adding concurrent data transfer to transport layer

In recent years, the internet has grown exponentially, and become more complex. This increased complexity potentially introduces more network-level instability. But for any end-to-end internet connection, maintaining the connection's throughput and reliability at a certain level is very important. This is because it can directly affect the connection's normal operation. Therefore, a challenging research task is to improve a network's connection performance by optimizing its throughput and reliability. This dissertation proposed an efficient and reliable transport layer protocol (called concurrent TCP (cTCP)), an extension of the current TCP protocol, to optimize end-to-end connection throughput and enhance end-to-end connection fault tolerance. The proposed cTCP protocol could aggregate multiple paths' bandwidth by supporting concurrent data transfer (CDT) on a single connection. Here concurrent data transfer was defined as the concurrent transfer of data from local hosts to foreign hosts via two or more end-to-end paths. An RTT-Based CDT mechanism, which was based on a path's RTT (Round Trip Time) to optimize CDT performance, was developed for the proposed cTCP protocol. This mechanism primarily included an RTT-Based load distribution and path management scheme, which was used to optimize connections' throughput and reliability. A congestion control and retransmission policy based on RTT was also provided. According to experiment results, under different network conditions, our RTT-Based CDT mechanism could acquire good CDT performance. Finally a CWND-Based CDT mechanism, which was based on a path's CWND (Congestion Window), to optimize CDT performance was introduced. This mechanism primarily included: a CWND-Based load allocation scheme, which assigned corresponding data to paths based on their CWND to achieve aggregate bandwidth; a CWND-Based path management, which was used to optimize connections' fault tolerance; and a congestion control and retransmission management policy, which was similar to regular TCP in its separate path handling. According to corresponding experiment results, this mechanism could acquire near-optimal CDT performance under different network conditions.

Evangelical young women, contemporary Christianity, and an empowering self- understanding: a study into how contemporary women of faith understand themselves and God in relation to Dei, Holy Scripture and Christian mission

This thesis combines historical reflection with qualitative research to examine how Christian young women from Evangelical traditions are developing religious self- understanding in empowering ways. It seeks to establish connections between the ways in which historians and feminist theologians have responded to forces of restriction and limitation in Christian women’s past, and the strategies of self-empowerment adopted by Evangelical young women today. This study approaches Christian history and the present condition of female self-understanding through three central questions: How do young women understand themselves in relation to the imago Dei? How do young women understand themselves in relation to the Bible? How do young women understand themselves in relation to Christian mission? The first chapter addresses the ways in which young women are responding to historic denials of woman as the imago Dei and concepts of female inferiority or especial guilt by reclaiming possession of the divine image. The next section discusses how young women are relating to the Bible in empowering ways, both by adopting similar strategies to those utilised throughout Christianity’s past, and through the development of their own patterns of interpretation. Finally, this thesis draws attention to Christian mission as a space of empowerment, examining how young women develop life-enriching knowledge of God and self through involvement with mission. This thesis proposes that as young women continue to develop strategies that enable them to understand themselves and their faith in empowering ways, knowledge of their innate dignity and potential will inspire them — and those who come after them — to witness to God freely and fully in all contexts.

Magnetic ordering of EuTe/PbTe multilayers determined by x-ray resonant diffraction

In this work we use resonant x-ray diffraction combined with polarization analysis of the diffracted beam to study the magnetic ordering in EuTe/PbTe multilayers. The presence of satellites at the (1/2 1/2 1/2) magnetic reflection of a 50 /repetition EuTe/PbTe superlattice demonstrated the existence of magnetic correlations among the alternated EuTe layers. The behavior of the satellites intensity as T increases toward the Neel temperature T(N) indicates that these correlations persist nearly up to T(N) and suggests the preferential decrease of the magnetic order parameter of external monolayers of each EuTe layer within the superlattice. (C) 2008 American Institute of Physics.

Modeling technique for honeycomb FRP deck bridges via finite elements

Honeycomb structures have been used in different engineering fields. In civil engineering, honeycomb fiber-reinforced polymer (FRP) structures have been used as bridge decks to rehabilitate highway bridges in the United States. In this work, a simplified finite-element modeling technique for honeycomb FRP bridge decks is presented. The motivation is the combination of the complex geometry of honeycomb FRP decks and computational limits, which may prevent modeling of these decks in detail. The results from static and modal analyses indicate that the proposed modeling technique provides a viable tool for modeling the complex geometry of honeycomb FRP bridge decks. The modeling of other bridge components (e.g., steel girders, steel guardrails, deck-to-girder connections, and pier supports) is also presented in this work.

Aesthetic value: between universality and exclusivity

This study brings a reflection on aesthetic values, trying to consider connections between universality, social exclusion and contemporary violence.

Optically driven micromachine elements

We report on a proof of principle demonstration of an optically driven micromachine element. Optical angular momentum is transferred from a circularly polarized laser beam to a birefringent particle confined in an optical tweezers trap. The optical torque causes the particle to spin at up to 350 Hz, and this torque is harnessed to drive an optically trapped microfabricated structure. We describe a photolithographic method for producing the microstructures and show how a light driven motor could be used in a micromachine system. (C) 2001 American Institute of Physics.

Comporta de vigas: dimensionamento e análise estrutural

As comportas de vigas de fundo, objecto de estudo no presente trabalho, são essenciais devido à sua capacidade de controlo do fluxo de água em casos de emergência. Assim este trabalho visou o dimensionamento e análise estrutural de uma comporta dessa natureza. Para o seu dimensionamento foi essencial a norma DIN19704-1:1998, que define todos os padrões que devem ser levados em conta numa construção hidráulica em aço. Deste modo, após uma breve descrição do enquadramento e do estado da arte relativamente a este assunto, foram apresentados ao longo do trabalho, os cálculos dos principais componentes mecânicos que fazem parte dum projecto de uma comporta de vigas. Para comprovar a validade do dimensionamento da comporta realizado através da norma, recorreu-se a um software de análise e simulação por elementos finitos, COSMOSWorks, no sentido de assim prever o comportamento mecânico em análise estática linear, que as solicitações mecânicas em presença têm sobre a comporta. Os resultados da comparação entre o dimensionamento teórico e a análise de tensões através do COSMOSWorks nos elementos mais críticos da estrutura, permitem concluir globalmente que a comporta está bem dimensionada tendo em conta os esforços que tem de suportar.

Monitorização integrada para sistemas de alimentação distribuídos

Mestrado em Engenharia Electrotécnica e de Computadores

Aprender matemática através de expressões : uma reflexão no âmbito da prática de estágio na Educação Pré-Escolar e no 1.º Ciclo do Ensino Básico

Mestrado (PES II), Educação Pré-Escolar e Ensino do 1.º Ciclo do Ensino Básico, 22 de Junho de 2015, Universidade dos Açores.

A Técnica de Dança Clássica na Performance Contemporânea : desenvolvimento de competências técnicas e artísticas, nos alunos dos últimos anos da Academia de Dança Contemporânea de Setúbal, visando a sua entrada no meio artístico profissional

Relatório Final de Estágio apresentado à Escola Superior de Dança com vista à obtenção do grau de Mestre em Ensino de Dança.

Prática de ensino supervisionado no 1.º e 2.º ciclo do ensino básico: perspetivas e práticas sobre a realização dos trabalhos para casa

Relatório Final apresentado à Escola Superior de Educação de Lisboa para obtenção de grau de mestre em Ensino do 1.º e do 2.º Ciclo do Ensino Básico

Integrated didactics: an example of a curriculum model enhancing knowledge crossing

In this paper, we introduce an innovative course in the Portuguese Context, the Master's Course in “Integrated Didactics in Mother Tongue, Maths, Natural and Social Sciences”, taking place at the Lisbon School of Education and discussing in particular the results of the evaluation made by the students who attended the Curricular Unit - Integrated Didactics (CU-ID). This course was designed for in-service teachers of the first six years of schooling and intends to improve connections between different curriculum areas. In this paper, we start to present a few general ideas about curriculum development; to discuss the concept of integration; to present the principles and objectives of the course created as well as its structure; to describe the methodology used in the evaluation process of the above mentioned CU-ID. The results allow us to state that the students recognized, as positive features of the CU-ID, the presence in all sessions of two teachers simultaneously from different scientific areas, as well as invitations issued to specialists on the subject of integration and to other teachers that already promote forms of integration in schools. As negative features, students noted a lack of integrated purpose, applying simultaneously the four scientific areas of the course, and also indicated the need to be familiar with more models of integrated education. Consequently, the suggestions for improvement derived from these negative features. The students also considered that their evaluation process was correct, due to the fact that it was focused on the design of an integrated project for one of the school years already mentioned.

MAC regenerative analysis of wireless Ad-Hoc networks

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Electrotécnica e de Computadores

Study of nuclear reactions relevant for astrophysics by Micro-AMS

Dissertação para obtenção do Grau de Doutor em Física