Mathematical modeling of pressurized system behaviour with entrapped air

The presence of entrapped air in pressurized hydraulic systems is considered a critical condition for the infrastructure security, due to the transient pressure enhancement related with its dynamic behaviour, similar to non-linear spring action. A mathematical model for the assessment of hydraulic transients resulting from rapid pressurizations, under referred condition is presented. Water movement was modeled through the elastic column theory considering a moving liquid boundary and the entrapped air pocket as lumped gas mass, where the acoustic effects are negligible. The method of characteristics was used to obtain the numerical solution of the liquid flow. The resulting model is applied to an experimental set-up having entrapped air in the top of a vertical pipe section and the numerical results are analyzed.

Extreme Value Theory versus traditional GARCH approaches applied to financial data: a comparative evaluation

Although stock prices fluctuate, the variations are relatively small and are frequently assumed to be normal distributed on a large time scale. But sometimes these fluctuations can become determinant, especially when unforeseen large drops in asset prices are observed that could result in huge losses or even in market crashes. The evidence shows that these events happen far more often than would be expected under the generalized assumption of normal distributed financial returns. Thus it is crucial to properly model the distribution tails so as to be able to predict the frequency and magnitude of extreme stock price returns. In this paper we follow the approach suggested by McNeil and Frey (2000) and combine the GARCH-type models with the Extreme Value Theory (EVT) to estimate the tails of three financial index returns DJI,FTSE 100 and NIKKEI 225 representing three important financial areas in the world. Our results indicate that EVT-based conditional quantile estimates are much more accurate than those from conventional AR-GARCH models assuming normal or Student’s t-distribution innovations when doing out-of-sample estimation (within the insample estimation, this is so for the right tail of the distribution of returns).

Between theory and practice – teaching maths to elementary school students in Poland

The development of children's school achievements in mathematics is one of the most important aims of education in Poland. The results of research concerning monitoring of school achievements in maths is not optimistic. We can observe low levels of children’s understanding of the merits of maths, self-developed strategies in solving problems and practical usage of maths skills. This article frames the discussion of this problem in its psychological and didactic context and analyses the causes as they relate to school practice in teaching maths

Microscopic Theory of Anchoring Transitions at the Surfaces of Pure Liquid-Crystals and their Mixtures .1. The Fowler Approximation

We have generalized earlier work on anchoring of nematic liquid crystals by Sullivan, and Sluckin and Poniewierski, in order to study transitions which may occur in binary mixtures of nematic liquid crystals as a function of composition. Microscopic expressions have been obtained for the anchoring energy of (i) a liquid crystal in contact with a solid aligning surface; (ii) a liquid crystal in contact with an immiscible isotropic medium; (iii) a liquid crystal mixture in contact with a solid aligning surface. For (iii), possible phase diagrams of anchoring angle versus dopant concentration have been calculated using a simple liquid crystal model. These exhibit some interesting features including re-entrant conical anchoring, for what are believed to be realistic values of the molecular parameters. A way of relaxing the most drastic approximation implicit in the above approach is also briefly discussed.

Simulation and theory of hybrid aligned liquid crystal films

We present a study of the effects of nanoconfinement on a system of hard Gaussian overlap particles interacting with planar substrates through the hard-needle-wall potential, extending earlier work by two of us [D. J. Cleaver and P. I. C. Teixeira, Chem. Phys. Lett. 338, 1 (2001)]. Here, we consider the case of hybrid films, where one of the substrates induces strongly homeotropic anchoring, while the other favors either weakly homeotropic or planar anchoring. These systems are investigated using both Monte Carlo simulation and density-functional theory, the latter implemented at the level of Onsager's second-virial approximation with Parsons-Lee rescaling. The orientational structure is found to change either continuously or discontinuously depending on substrate separation, in agreement with earlier predictions by others. The theory is seen to perform well in spite of its simplicity, predicting the positional and orientational structure seen in simulations even for small particle elongations.

A aquisição de competências musicais no ensino da Técnica de Dança Clássica no 2º ano no Conservatório de Música da Jobra

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

As políticas e práticas culturais no seio da Rede Nacional de Teatros e Cineteatros

Artigo baseado na comunicação proferida no 7º Congresso SOPCOM: Comunicação Global, Cultura e Tecnologia, realizado na Faculdade de Letras da Universidade do Porto, Porto, Portugal, 15 -17 dezembro de 2011

James W. Carey as critical theorist of the information age

This paper suggests that the thought of the North-American critical theorist James W. Carey provides a relevant perspective on communication and technology. Having as background American social pragmatism and progressive thinkers of the beginning of the 20th century (as Dewey, Mead, Cooley, and Park), Carey built a perspective that brought together the political economy of Harold A. Innis, the social criticism of David Riesman and Charles W. Mills and incorporated Marxist topics such as commodification and sociocultural domination. The main goal of this paper is to explore the connection established by Carey between modern technological communication and what he called the “transmissive model”, a model which not only reduces the symbolic process of communication to instrumentalization and to information delivery, but also politically converges with capitalism as well as power, control and expansionist goals. Conceiving communication as a process that creates symbolic and cultural systems, in which and through which social life takes place, Carey gives equal emphasis to the incorporation processes of communication.If symbolic forms and culture are ways of conditioning action, they are also influenced by technological and economic materializations of symbolic systems, and by other conditioning structures. In Carey’s view, communication is never a disembodied force; rather, it is a set of practices in which co-exist conceptions, techniques and social relations. These practices configure reality or, alternatively, can refute, transform and celebrate it. Exhibiting sensitiveness favourable to the historical understanding of communication, media and information technologies, one of the issues Carey explored most was the history of the telegraph as an harbinger of the Internet, of its problems and contradictions. For Carey, Internet was seen as the contemporary heir of the communications revolution triggered by the prototype of transmission technologies, namely the telegraph in the 19th century. In the telegraph Carey saw the prototype of many subsequent commercial empires based on science and technology, a pioneer model for complex business management; an example of conflict of interest for the control over patents; an inducer of changes both in language and in structures of knowledge; and a promoter of a futurist and utopian thought of information technologies. After a brief approach to Carey’s communication theory, this paper focuses on his seminal essay "Technology and ideology. The case of the telegraph", bearing in mind the prospect of the communication revolution introduced by Internet. We maintain that this essay has seminal relevance for critically studying the information society. Our reading of it highlights the reach, as well as the problems, of an approach which conceives the innovation of the telegraph as a metaphor for all innovations, announcing the modern stage of history and determining to this day the major lines of development in modern communication systems.

Teacher placement report: investigation: action research project investigating methods for promoting creativity in double bass students attending a portuguese music school

The investigation which employed the action research method (qualitative analysis)was divided into four fases. In phases 1-3 the participants were six double bass students at Nossa Senhora do Cabo Music School. Pilot exercises in creativity were followed by broader and more ambitious projects. In phase 4 the techniques were tested and amplified during a summer course for twelve double bass students at Santa Cecilia College.

Elaboração e aplicação de um Programa de Treino aos alunos do 2º ano de Dança, da Academia de Dança do Vale do Sousa, com vista à realização do exame de Grau 5 da Royal Academy of Dance

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

Action, reaction and protest by publishers in 1960s Portugal: books and other publications in the Catholic opposition

The authoritarian regime of the Portuguese Estado Novo (New State), the longest dictatorship in twentieth-century Western Europe, suffered one of its most serious threats during the late 1950s and the whole of the following decade. An array of events and dynamics of opposition to the regime and condemnation of the political and social situation in Portugal appeared at that time. One of the core groups that displayed their dissidence in the 1960s, with the awakening of their critical conscience, originated in Catholic sectors that rallied the laity and the clergy to express their disagreement or even break with the government of Salazar (and, later, Marcelo Caetano). This article aims to establish the role of print culture and, in particular, publishing in the opposition’s mobilisation of Catholics who criticised the Estado Novo. It will also closely examine the contribution of certain publishers to the formulation of the terms of this mobilisation, in publishing new authors and topics and creating new printed forums (e.g. periodicals) for discussion and reflection. The most detailed case will be that of the publishing house Livraria Moraes Editora, under the command of the publisher António Alçada Baptista.

On lattices from combinatorial game theory modularity and a representation theorem: finite case

We show that a self-generated set of combinatorial games, S. may not be hereditarily closed but, strong self-generation and hereditary closure are equivalent in the universe of short games. In [13], the question "Is there a set which will give a non-distributive but modular lattice?" appears. A useful necessary condition for the existence of a finite non-distributive modular L(S) is proved. We show the existence of S such that L(S) is modular and not distributive, exhibiting the first known example. More, we prove a Representation Theorem with Games that allows the generation of all finite lattices in game context. Finally, a computational tool for drawing lattices of games is presented. (C) 2014 Elsevier B.V. All rights reserved.

Theory and phenomenology of two-higgs-doublet models

We discuss theoretical and phenomenological aspects of two-Higgs-doublet extensions of the Standard Model. In general, these extensions have scalar mediated flavour changing neutral currents which are strongly constrained by experiment. Various strategies are discussed to control these flavour changing scalar currents and their phenomenological consequences are analysed. In particular, scenarios with natural flavour conservation are investigated, including the so-called type I and type II models as well as lepton-specific and inert models. Type III models are then discussed, where scalar flavour changing neutral currents are present at tree level, but are suppressed by either a specific ansatz for the Yukawa couplings or by the introduction of family symmetries leading to a natural suppression mechanism. We also consider the phenomenology of charged scalars in these models. Next we turn to the role of symmetries in the scalar sector. We discuss the six symmetry-constrained scalar potentials and their extension into the fermion sector. The vacuum structure of the scalar potential is analysed, including a study of the vacuum stability conditions on the potential and the renormalization-group improvement of these conditions is also presented. The stability of the tree level minimum of the scalar potential in connection with electric charge conservation and its behaviour under CP is analysed. The question of CP violation is addressed in detail, including the cases of explicit CP violation and spontaneous CP violation. We present a detailed study of weak basis invariants which are odd under CP. These invariants allow for the possibility of studying the CP properties of any two-Higgs-doublet model in an arbitrary Higgs basis. A careful study of spontaneous CP violation is presented, including an analysis of the conditions which have to be satisfied in order for a vacuum to violate CP. We present minimal models of CP violation where the vacuum phase is sufficient to generate a complex CKM matrix, which is at present a requirement for any realistic model of spontaneous CP violation.

Aplicação do princípio das ondas de Elliott à bolsa portuguesa

Tese para a obtenção do grau de Doutor em Economia, especialidade de Economia da Empresa