Melhoramento de terrenos de fundação através de "cutter soil mixing"

Dissertação para obtenção do Grau de Mestre em Engenharia Civil Perfil de Estruturas e Geotecnia (elaborada no Laboratório Nacional de Engenharia Civil no âmbito do protocolo entre a FCT-UNL e o LNEC)

Ambivalent Islam: the identity construction of Muslims under Portuguese colonial rule

This article wishes to contribute to the study of the historical processes that have been spotting Muslim populations as favourite targets for political analysis and governance. Focusing on the Portuguese archives, civil as well as military, the article tries to uncover the most conspicuous identity representations (mainly negative or ambivalent) that members of Portuguese colonial apparatus built around Muslim communities living in African colonies, particularly in Guinea-Bissau and Mozambique. The paper shows how these culturally and politically constructed images were related to the more general strategies by which Portuguese imagined their own national identity, both as ‘European’ and as ‘coloniser’ or ‘imperial people’. The basic assumption of this article is that policies enforced in a context of inter-ethnic and religious competition are better understood when linked to the identity strategies inherent to them. These are conceived as strategic constructions aimed at the preservation, the protection and the imaginary expansion of the subject, who looks for groups to be included in and out-groups to reject, exclude, aggress or eliminate. We think that most of the inter-ethnic relationships and conflicts, as well as the very experience of ethnicity, are born from this identity matrix.

A rule-based grapheme-to-phone converter for TTS systems in european portuguese

In this paper, a linguistically rule-based grapheme-to-phone (G2P) transcription algorithm is described for European Portuguese. A complete set of phonological and phonetic transcription rules regarding the European Portuguese standard variety is presented. This algorithm was implemented and tested by using online newspaper articles. The obtained experimental results gave rise to 98.80% of accuracy rate. Future developments in order to increase this value are foreseen. Our purpose with this work is to develop a module/ tool that can improve synthetic speech naturalness in European Portuguese. Other applications of this system can be expected like language teaching/learning. These results, together with our perspectives of future improvements, have proved the dramatic importance of linguistic knowledge on the development of Text-to-Speech systems (TTS).

Ambivalent Islam: the identity construction of Muslims under Portuguese colonial rule

This article wishes to contribute to the study of the historical processes that have been spotting Muslim populations as favourite targets for political analysis and governance. Focusing on the Portuguese archives, civil as well as military, the article tries to uncover the most conspicuous identity representations (mainly negative or ambivalent) that members of Portuguese colonial apparatus built around Muslim communities living in African colonies, particularly in Guinea- Bissau and Mozambique. The paper shows how these culturally and politically constructed images were related to the more general strategies by which Portuguese imagined their own national identity, both as ‘European’ and as ‘coloniser’ or ‘imperial people’. The basic assumption of this article is that policies enforced in a context of interethnic and religious competition are better understood when linked to the identity strategies inherent to them. These are conceived as strategic constructions aimed at the preservation, protection and imaginary expansion of the subject, who looks for groups to be included in and out-groups to reject, exclude, aggress or eliminate. The author argues that most of the inter-ethnic relationships and conflicts, as well as the very experience of ethnicity, are born from this identity matrix.

Abordagem às soluções de contenção de escavações usando a técnica Deep Soil Mixing

Dissertação para obtenção do Grau de Mestre em Engenharia Geológica-Geotecnia

Facilitated CO2 separation membranes: mixing cyano and amino acid-based ionic liquids

Dissertação para obtenção do Grau de Mestre em Engenharia Química e Bioquímica

Harvest control rule vs optimal harvesting of an age-structured population: The case of the Ibero-Atlantic Sardine Fishery

Research Masters

Probing dispersion and re-agglomeration phenomena upon melt-mixing of polymer-functionalized graphite nanoplates

A one-step melt-mixing method is proposed to study dispersion and re-agglomeration phenomena of the as-received and functionalized graphite nanoplates in polypropylene melts. Graphite nanoplates were chemically modified via 1,3-dipolar cycloaddition of an azomethine ylide and then grafted with polypropylene-graft-maleic anhydride. The effect of surface functionalization on the dispersion kinetics, nanoparticle re-agglomeration and interface bonding with the polymer is investigated. Nanocomposites with 2 or 10 wt% of as-received and functionalized graphite nanoplates were prepared in a small-scale prototype mixer coupled to a capillary rheometer. Samples were collected along the flow axis and characterized by optical microscopy, scanning electron microscopy and electrical conductivity measurements. The as-received graphite nanoplates tend to re-agglomerate upon stress relaxation of the polymer melt. The covalent attachment of a polymer to the nanoparticle surface enhances the stability of dispersion, delaying the re-agglomeration. Surface modification also improves interfacial interactions and the resulting composites presented improved electrical conductivity.

Dispersion of graphite nanoplates during melt mixing

Artigo publicado a convite da Society for Polymer Engineers

Improvign mixing processes with the help of numerical tools

In several industrial applications, highly complex behaviour materials are used together with intricate mixing processes, which difficult the achievement of the desired properties for the produced materials. This is the case of the well-known dispersion of nano-sized fillers in a melt polymer matrix, used to improve the nanocomposite mechanical and/or electrical properties. This mixing is usually performed in twin-screw extruders, that promote complex flow patterns, and, since an in loco analysis of the material evolution and mixing is difficult to perform, numerical tools can be very useful to predict the evolution and behaviour of the material. This work presents a numerical based study to improve the understanding of mixing processes. Initial numerical studies were performed with generalized Newtonian fluids, but, due to the null relaxation time that characterize this type of fluids, the assumption of viscoelastic behavior was required. Therefore, the polymer melt was rheologically characterized, and, a six mode Phan-Thien-Tanner and Giesekus models were used to fit the rheological data. These viscoelastic rheological models were used to model the process. The conclusions obtained in this work provide additional and useful data to correlate the type and intensity of the deformation history promoted to the polymer nanocomposite and the quality of the mixing obtained.

kinetic analysis of ester hydrolysis reactions considering volume and enthalpy changes due to mixing

Magdeburg, Univ., Fak. für Verfahrens- und Systemtechnik, Diss., 2012

Optimization of radial jets mixing in cross-flow of combustion chambers using computational fluid dynamics

Cross-Flow, Radial Jets Mixing, Temperature Homogenization, Optimization, Combustion Chamber, CFD

Free triples, large indifference classes and the majority rule

We present a new domain of preferences under which the majority relation is always quasi-transitive and thus Condorcet winners always exist. We model situations where a set of individuals must choose one individual in the group. Agents are connected through some relationship that can be interpreted as expressing neighborhood, and which is formalized by a graph. Our restriction on preferences is as follows: each agent can freely rank his immediate neighbors, but then he is indifferent between each neighbor and all other agents that this neighbor "leads to". Hence, agents can be highly perceptive regarding their neighbors, while being insensitive to the differences between these and other agents which are further removed from them. We show quasi-transitivity of the majority relation when the graph expressing the neighborhood relation is a tree. We also discuss a further restriction allowing to extend the result for more general graphs. Finally, we compare the proposed restriction with others in the literature, to conclude that it is independent of any previously discussed domain restriction.

Mixing invariants of hyperbolic 3-manifolds

Let M be a compact hyperbolic 3-manifold with incompressible boundary. Consider a complete hyperbolic metric on int(M). To each geometrically finite end of int(M) are traditionnaly associated 3 different invariants : the hyperbolic metric associated to the conformal structure at infinity, the hyperbolic metric on the boundary of the convex core and the bending measured lamination of the convex core. In this note we show how invariants of different types can be realised in the different ends.

Distinct neurophysiological mechanisms mediate mixing costs and switch costs.

Using event-related potentials (ERPs), we investigated the neural response associated with preparing to switch from one task to another. We used a cued task-switching paradigm in which the interval between the cue and the imperative stimulus was varied. The difference between response time (RT) to trials on which the task switched and trials on which the task repeated (switch cost) decreased as the interval between cue and target (CTI) was increased, demonstrating that subjects used the CTI to prepare for the forthcoming task. However, the RT on repeated-task trials in blocks during which the task could switch (mixed-task blocks) were never as short as RTs during single-task blocks (mixing cost). This replicates previous research. The ERPs in response to the cue were compared across three conditions: single-task trials, switch trials, and repeat trials. ERP topographic differences were found between single-task trials and mixed-task (switch and repeat) trials at approximately 160 and approximately 310 msec after the cue, indicative of changes in the underlying neural generator configuration as a basis for the mixing cost. In contrast, there were no topographic differences evident between switch and repeat trials during the CTI. Rather, the response of statistically indistinguishable generator configurations was stronger at approximately 310 msec on switch than on repeat trials. By separating differences in ERP topography from differences in response strength, these results suggest that a reappraisal of previous research is appropriate.