Avaliação do ensaio de pull-out na estimativa da resistência à compressão do betão em idades jovens

Dissertação para obtenção do Grau de Mestre em Engenharia Civil – Perfil Estruturas

Fitting the yield curve

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Finance from the NOVA – School of Business and Economics

A way out of the crises for expatriates: The mediating role of psychological capital

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

Hub-and-spoke Interoperability: an out of the skies approach for large-scale data interoperability

Dissertação para obtenção do Grau de Doutor em Engenharia Electrotécnica e de Computadores

Dual track sell-out: Signaling through IPO and Underpricing

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Finance from the NOVA – School of Business and Economics

Buy, sell and chatter: A case analysis of a Lisbon flea market

This thesis aims explore the sociocultural as well as economic significance of the modern-day flea market, as a form of alternative marketplace system. More specifically, the main goal of the research is to determine the motivation for participation in flea markets of different participants, from vendors to consumers, using an interactionist perspective. By studying these groups in details, I seek to explore the embeddedness of social aspects in economic activity and vice versa. The basic assumption is to put aside the previous notions of the flea market as a second-order system with implied inferiority, and to explore the potential of the flea market to both challenge and complement more formal marketplace systems, by comparing and contrasting the flea market with market venues that belong to the formal sector. Feira da Ladra in Lisbon, Portugal, the oldest a hugely successful flea market in Europe, was chosen to be the research site, where its economic participants were studied in details in various exchanges, using naturalistic observations, semi-structured interviews and a sociocultural perspective.

Overstock and stock-out in Volkswagen Autoeuropa

The following work is a case study of overstock and stock-out problems at Volkswagen Autoeuropa (VWAE). It introduces the supply chain of Autoeuropa and specializes then on failures connected to inventory problems. Having a successful supply chain is important in a world where products become more and more similar as it can give to companies an edge over their competitors. The case shows three practices that VWAE uses to prevent and to overcome stock problems. Information was gathered by doing interviews with different managers, by analyzing the company’s key processes and by literature research related to the topics of supply chain management and flexibility in the supply chain. Three practices were further investigated: the use of alternative parts, support of the supplier and a rating system of suppliers. In the question section of this work the importance of flexibility and Supplier Relationship Management (SRM) when connected to supply chain management are explained. The described different practices are numerically analyzed and it is concluded that each practice brings both cost savings and the possibility of achieving target numbers to the company, showing the company’s flexibility to react to supply chain disturbances. Because of confidentiality reasons, persons in the case are fictionalized and numbers are wherever possible equalized to 100 in order to display true proportions.

Breaking Down and Breaking Out: Beckett’s ‘Absolute Liminality’ in the Third Age of Capitalist Traumas

Fundação para a Ciência e a Tecnologia (FCT), Fundação Millennium bcp

Numerical Assessment of the out-of-plane response of a brick masonry structure without box behaviour

This paper presents the assessment of the out-of-plane response due to seismic loading of a masonry structure without rigid diaphragm. This structure corresponds to real scale brick masonry specimen with a main façade connected to two return walls. Two modelling approaches were defined for this evaluation. The first one consisted on macro modelling, whereas the second one on simplified micro modelling. As a first step of this study, static nonlinear analyses were conducted to the macro model aiming at evaluating the out-of-plane response and failure mechanism of the masonry structure. A sensibility analyses was performed in order to assess the mesh size and material model dependency. In addition, the macro models were subjected to dynamic nonlinear analyses with time integration in order to assess the collapse mechanism. Finally, these analyses were also applied to a simplified micro model of the masonry structure. Furthermore, these results were compared to experimental response from shaking table tests. It was observed that these numerical techniques simulate correctly the in-plane behaviour of masonry structures. However, the

Out-of-plane behavior of masonry infill walls

In order to investigate the out-of-plane behaviour of masonry infill walls, quasi-static testing was performed on a masonry infill walls built inside a reinforced concrete frame by means of an airbag system to apply the uniform out-of-plane load to each component of the infill. The main advantage of this testing setup is that the out-of-plane loading can be applied more uniformly in the walls, contrarily to point load configuration. The test was performed under displacement control by selecting the mid-point of the infill as control point. Input and output air in the airbag was controlled by using a software to apply a specific displacement in the control point of the infill wall. The effect of the distance between the reaction frame of the airbag and the masonry infill on the effective contact area was previously analysed. Four load cells were attached to the reaction frame to measure the out-of-plane force. The effective contact area of the airbag was calculated by dividing the load measured in load cells by the pressure inside the airbag. When the distance between the reaction walls and the masonry infill wall is smaller, the effective area is closer to the nominal area of the airbag. Deformation and crack patterns of the infill confirm the formation of arching mechanism and two-way bending of the masonry infill. Until collapse of the horizontal interface between infill and upper beam in RC frame, the infill bends in two directions but the failure of that interface which is known as weakest interface due to difficulties in filling the mortar between bricks of last row and upper beam results in the crack opening trough a well-defined path and the consequent collapse of the infill.

In-plane and out-of plane experimental characterization of rc masonry infilled frames

Seismic investigations of typical south European masonry infilled frames were performed by testing two reduced scale specimens: one in the in-plane direction and another in the out-ofplane direction. Information about geometry and reinforcement scheme of those structures constructed in 1980s were obtained by [1]. The specimen to be tested in the in-plane direction was constructed as double leaf masonry while the specimen for testing in the out-of-plane direction is constructed with only its exterior leaf since the recent earthquakes have highlighted the vulnerability of the external leaf of the infills in out-of-plane direction [2]. The tests were performed by applying the pre-defined values of displacements in the in-plane and out-of-plane directions in the control points. For in-plane testing it was done by hydraulic actuator and for out-of-plane testing through the application of an airbag. Input and output air in the airbag was controlled by using a software to apply a specific displacement in the control point of the infill wall. Mid-point of the infill was assumed as a control point for outof- plane testing. Deformation and crack patterns of the infill confirm the formation of two-way arching mechanism of the masonry infill until collapse of the upper horizontal interface between infill and frame which is known as weakest interface due to difficulties in filling the mortar between bricks of last row and upper beam. This results in the crack opening through a welldefined path and the consequent collapse of the infill.

Preschool education in Brazil: does public supply crowd out private enrollment?

Expanding access to preschool education is a particularly important policy issue in developing countries, where enrollment rates are generally much lower, and where private institutions constitute a much larger share of the formal preschool sector, than in developed countries. This paper examines if an expansion in the supply of public preschool crowds-out private enrollment using rich data for municipalities in Brazil from 2000 to 2006, where federal transfers to local governments change discontinuously with given population thresholds. Results from a regression-discontinuity design reveal that larger federal transfers lead to a significant expansion of local public preschool services, but show no evidence of crowding-out of private enrollment, nor of negative impacts on the quality of private providers. This finding is consistent with a theory in which households differ in willingness-to-pay for preschool services, and private suppliers optimally adjust prices in response to an expansion of lower-quality, free-of-charge public supply. In the context of the model, the absence of crowding-out effects of more public preschool providers can be rationalized by the existence of relatively large differences in willingness-to-pay for preschool services across different demand segments. Our theoretical and empirical findings therefore suggest that in developing country settings characterized by relatively high income inequality, an expansion in public preschool supply will likely significantly increase enrollment among the poorest segments of society, and need not have adverse effects on the quantity or quality of local private supply.

Dynamic interface model for masonry walls subjected to high strain rate out-of-plane loads

The present study proposes a dynamic constitutive material interface model that includes non-associated flow rule and high strain rate effects, implemented in the finite element code ABAQUS as a user subroutine. First, the model capability is validated with numerical simulations of unreinforced block work masonry walls subjected to low velocity impact. The results obtained are compared with field test data and good agreement is found. Subsequently, a comprehensive parametric analysis is accomplished with different joint tensile strengths and cohesion, and wall thickness to evaluate the effect of the parameter variations on the impact response of masonry walls.

Girls out of school. State, culture and education in poor rural Lao People's Democratic Republic

Tese de Doutoramento em Sociologia