“Landscape and Heritage of Hydroelectricity in Portugal”

Hydroelectric power plants provided countries with scarcity of coal, such as Portugal, with a vital source of energy for the production of electricity in large quantities. Therefore, since the late 19th century the use of waterfalls as producers of electric power was a topic of study and interest among engineers and the matter was regularly discussed at the Association of Portuguese Civilian Engineers. The great hydroelectric power plants, considered by many as the cathedrals of the second industrial revolution are an important industrial heritage which is important to value and appreciate. Hydroelectricity also gave origin to new landscapes and the problem today regards the management of this new landscape and the construction of new patrimonial values

Asserting the Portuguese Civil Engineering Identity: the Role Played by the École des ponts et chaussées

This paper focuses on the Portuguese engineers who returned to Portugal following a training period at École des Ponts et Chaussées, in Paris between 1831 and 1870. During the 19th century, in spite of the creation of engineering schools, such as the Military Academy (1836), the Polytechnic School of Lisbon (1837), the Polytechnic Academy of Oporto (1837), the number of engineers to ensure the planning and the direction of the public works remained insufficient. Moreover, the education provided by these schools granted almost no room for fieldwork. Like in the other European States, some Portuguese engineers tried to complete their training in foreign countries, in particular by attending schools such as the École des Ponts et Chaussées de Paris. The studies which they carried out as well as the projects and the “missions d’études” enabled them to intervene in various areas, from the construction of bridges and railways to agricultural hydraulics on their return to Portugal. Following their return, these engineers played an important role both in the transfer of knowledge as well as in updating Portuguese engineering. They designed and directed various public works and transmitted to their subordinates the most modern methods of planning and construction of roads, railways and seaports. In addition, they were appointed to political and administrative positions in particular within the Ministério das Obras Públicas, Comércio e Indústria created in 1852, in the context of which they had to evaluate, authorize or reject various engineering projects. Finally, some were appointed professors in Portuguese engineering schools where they taught new theories, methods and practices of civil engineering which they had learnt in Paris or during trips abroad

First study of the three-gluon static potential in Lattice QCD

We estimate the potential energy for a system of three static gluons in Lattice QCD. This is relevant for the different models of three-body glueballs have been proposed in the literature, either for gluons with a constituent mass, or for massless ones. A Wilson loop adequate to the static hybrid three-body system is developed. We study different spacial geometries, to compare the starfish model with the triangle model, for the three-gluon potential. We also study two different colour structures, symmetric and antisymmetric, and compare the respective static potentials. A first simulation is performed in a $24^3 \times 48$ periodic Lattice, with $\beta=6.2$ and $a \sim 0.072$ fm.Comment: 8 pages, 10 figure

On the Dirac equation with PT-symmetric potentials in the presence of position-dependent mass

The relativistic problem of fermions subject to a PT-symmetric potential in the presence of position-dependent mass is reinvestigated. The influence of the PT-symmetric potential in the continuity equation and in the orthonormalization condition are analyzed. In addition, a misconception diffused in the literature on the interaction of neutral fermions is clarified.Comment: 8 page

The Blackbody Radiation in D-Dimensional Universes

The blackbody radiation is analyzed in universes with $D$ spatial dimensions. With the classical electrodynamics suited to the universe in focus and recurring to the hyperspherical coordinates, it is shown that the spectral energy density as well as the total energy density are sensible to the dimensionality of the universe. Wien's displacement law and the Stefan-Boltzmann law are properly generalized

Higher-Order Gravitational Couplings and Modular Forms in N=2,D=4N=2,D=4 Heterotic String Compactifications

The restrictions of target--space duality are imposed at the perturbative level on the holomorphic Wilsonian couplings that encode certain higher-order gravitational interactions in $N=2, D=4$ heterotic string compactifications. A crucial role is played by non-holomorphic corrections. The requirement of symplectic covariance and an associated symplectic anomaly equation play an important role in determining their form. For models which also admit a type-II description, this equation coincides with the holomorphic anomaly equation for type-II compactifications in the limit that a specific K\"ahler-class modulus grows large. We explicitly evaluate some of the higher-order couplings for a toroidal compactification with two moduli $T$ and $U$, and we express them in terms of modular forms.Comment: 39 pages, Late

Heterotic Strings on Generalized Calabi-Yau Manifolds and Kaehler Moduli Stabilization

Compactifications of heterotic string theory on Generalized Calabi-Yau manifolds have been expected to give the same type of flexibility that type IIB compactifications on Calabi-Yau orientifolds have. In this note we generalize the work done on half-flat manifolds by other authors, to show how flux quantization occurs in the general case, by starting with a basis of harmonic forms and then extending it. However it turns out that only the axions associated with the non-harmonic directions in the space of Kaehler moduli, can be stabilized by the geometric (torsion) terms. Also we argue that there are no supersymmetric extrema of the potential when the second (and fourth) cohomology groups on the manifold are non-trivial. We suggest that threshold corrections to the classical gauge coupling function could solve these problems.Comment: 9 page

Tapada da Ajuda (Lisbon, Portugal) bronze age pin

A pin made of a copper-based alloy, found at Tapada da Ajuda (Lisbon, Portugal), a site dated to the beginning of the Late Bronze Age, was analyzed by X-ray fluorescence (XRF) spectroscopy and examined by microscopy. The results of this study and the unusual manufacturing technique of the pin are presented and discussed in this paper. Typology and production technique of this object seem to indicate a Central European origininfo:eu-repo/semantics/publishedVersio