The Álvaro Siza’s master plan, the architectural and structural projects for the reconstruction of Chiado, in Lisbon

On 1988 a frightful fire broke out in Chiado, destroying 18 buildings, of which most part only the facades remained. A reconstruction plan was committed to Álvaro Siza, who fulfilled the request to preserve the existing buildings. The bibliography is mainly devoted to historical events, and architectural design options. There are few publications on the constructive and structural interventions, the objective of this study, to allow a broader knowledge about the intervention at various levels and disciplines. This is of particular interest in the scope of the research project “Siza Atlas. Filling the gaps for World Heritage” which aims to contribute to the nomination of a group of Siza's works for the World Heritage List. The subject is analyzed trough complementary readings: research of bibliography, documentation from the archive and in situ observations. A comparative analysis of the interventions proves a common method of construction with reinforced concrete structure built in situ. The principal improvement of the plan concerned the public space, recreating paths between the blocks, connecting the lower and upper levels of Chiado.info:eu-repo/semantics/publishedVersio

Hyperbolic outer billiards : a first example

We present the first example of a hyperbolic outer billiard. More precisely we construct a one parameter family of examples which in some sense correspond to the Bunimovich billiards.Comment: 11 pages, 8 figures, to appear in Nonlinearit

Remodeling by fibroblasts alters the rate-dependent mechanical properties of collagen

The ways that fibroblasts remodel their environment are central to wound healing, development of musculoskeletal tissues, and progression of pathologies such as fibrosis. However, the changes that fibroblasts make to the material around them and the mechanical consequences of these changes have proven difficult to quantify, especially in realistic, viscoelastic three-dimensional culture environments, leaving a critical need for quantitative data. Here, we observed the mechanisms and quantified the mechanical effects of fibroblast remodeling in engineered tissue constructs (ETCs) comprised of reconstituted rat tail (type I) collagen and human fibroblast cells. To study the effects of remodeling on tissue mechanics, stress-relaxation tests were performed on ETCs cultured for 24, 48, and 72 h. ETCs were treated with deoxycholate and tested again to assess the ECM response. Viscoelastic relaxation spectra were obtained using the generalized Maxwell model. Cells exhibited viscoelastic damping at two finite time constants over which the ECM showed little damping, approximately 0.2 s and 10-30 s. Different finite time constants in the range of 1-7000 s were attributed to ECM relaxation. Cells remodeled the ECM to produce a relaxation time constant on the order of 7000 s, and to merge relaxation finite time constants in the 0.5-2 s range into a single time content in the 1 s range. Results shed light on hierarchical deformation mechanisms in tissues, and on pathologies related to collagen relaxation such as diastolic dysfunction. Statement of Significance As fibroblasts proliferate within and remodel a tissue, they change the tissue mechanically. Quantifying these changes is critical for understanding wound healing and the development of pathologies such as cardiac fibrosis. Here, we characterize for the first time the spectrum of viscoelastic (rate-dependent) changes arising from the remodeling of reconstituted collagen by fibroblasts. The method also provides estimates of the viscoelastic spectra of fibroblasts within a three-dimensional culture environment. Results are of particular interest because of the ways that fibroblasts alter the mechanical response of collagen at loading frequencies associated with cardiac contraction in humans. © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved

Reading of the evolution of the urban shape of the Plateau - City of Praia

An analysis of urban morphology of the historical nucleus (the Plateau) of Praia (Cape Verde) highlights the process of thinking and making a city expressed in António de Lencastre 's plan and its further development. For this, the processes of urban transformation occurring over time in the Plateau are shown. The methodology used for this urban analysis allowed an understanding of the intervention process on the Plateau through an interpretative analysis of morphological evolution obtained from: i) a detailed identification of cartography; ii) a comparative morphological analysis of urban development based on old and current cartography; iii) a vectorization of the maps through scale normalization (the letters were overlapped with the 2018 chart); iv) an identification of public buildings and public spaces; and v) a quantification of the elements of urban form. In the quantification of the elements of the urban form, the reading and interpretation of the different maps is synthesized through analytical drawings and tables.info:eu-repo/semantics/publishedVersio

Photon Self-Induced Spin to Orbital Conversion in TGG crystal at high laser power

In this paper, we present experimental evidence of a newly discovered third-order nonlinear optical process Self-Induced Spin-to-Orbital Conversion (SISTOC) of the photon angular momentum. This effect is the physical mechanism at the origin of the depolarization of very intense laser beams propagating in isotropic materials. The SISTOC process, like self-focusing, is triggered by laser heating leading to a radial temperature gradient in the medium. In this work we tested the occurrence of SISTOC in a terbium gallium garnet (TGG) rod for an impinging laser power of about 100~W. To study the SISTOC process we used different techniques: polarization analysis, interferometry and tomography of the photon orbital angular momentum. Our results confirm, in particular, that the apparent depolarization of the beam is due to the occurrence of maximal entanglement between the spin and orbital angular momentum of the photons undergoing the SISTOC process. This explanation of the true nature of the depolarization mechanism could be of some help in finding novel methods to reduce or to compensate for this usually unwanted depolarization effect in all cases where very high laser power and good beam quality are required.Comment: 6 pages, 10 figures, submitte

A characterization of quasi-rational polygons

The aim of this paper is to study quasi-rational polygons related to the outer billiard. We compare different notions introduced, and make a synthesis of those.Comment: 15 pages, 9 figure

A conceptual model for building design coordination using open source tools

Building Design Coordination is the process of communicating and integrating multidisciplinary designs into a single, coherent set of information that can be used for construction, to anticipate problems that would otherwise only be raised on the construction site. As projects grow in complexity and size, digital communication tools and other technological improvements have made it possible for physically distant design teams to collaborate in novel ways. More recently, BIM (Building Information Modelling), has opened even greater possibilities, although the design process nevertheless is often one of trial and error, demanding on each small change multiple possibilities to be considered, with decisions requiring to be validated among designers and other project stakeholders. Regardless of all the advantages that BIM has brought to the industry, testing for design changes in BIM models often requires a big effort and is a time-consuming activity that should be avoided whenever simpler processes can be used. Further developments on this study will propose a framework for building design coordination, using a non-relational graph database. The system can track design issues between unlimited users, organized into teams, handling formal project documents and keeping an historical record of the design development timeline. Since all the information regarding the design development process is stored in the form of Nodes and Relationships these can be intuitively be manipulated making it easier for teams to provide input on design decisions in real time with least cost impact to the project, providing at the same time access to pertinent information on the status of design issues and how the various stakeholders are contributing to the project. Through the use of reliable open source tools, a prototype can be implemented and made available to the industry professionals for testing, providing guidelines for modelling a Building Design Coordination system.info:eu-repo/semantics/publishedVersio

O Património e o sector da construção. Teoria e prática

A oferta formativa do setor da Construção contempla sobretudo a construção nova, quer ao nível da formação profissional, quer ao nível da licenciatura e mestrado integrado. As universidades continuam a graduar profissionais responsáveis por projetos e obras, sem formação adequada em Conservação do Património Arquitetónico, apesar de ser a maior fonte de emprego atual. Falta teoria mas todos praticam. Por isso assiste-se a tantas demolições e a construções em vez de “reabilitações” que anunciam, porque desconhecem o significado, intervenções irreversíveis e perda total da autenticidade. “Reabilitação” é a palavra da moda, em vez de “Conservação”, pois esta significa claramente “conservar”.info:eu-repo/semantics/publishedVersio

As abóbadas de combados da Sé de Braga e da igreja do convento de Jesus de Setúbal

A atribuição da autoria da abóbada da capela-mor da igreja do convento de Jesús de Setúbal tem sido polémica. Os Historiadores da Arte dividem-se entre Diogo Boitaca (c. 1460-1528), sobretudo baseados nas crónicas de Soror Leonor de São João, e João de Castilho (c. 1470-1552), por comparação arquitetónica com a abóbada da capela-mor da Sé de Braga. A abóbada de Sé de Braga está documentada como a primeira abóbada de combados (nervuras curvas entre chaves) construída em Portugal, por João de Castilho. Relativamente à abóbada de Setúbal, os dados são insuficientes: as crónicas datam de 1630, mais de 100 anos após a construção da igreja, e as análises arquitetónicas baseiam-se apenas na observação visual, carecem de provas. Este artigo apresenta a análise histórica e arquitetónica das duas abóbadas, desenvolvida no âmbito da tese de doutoramento “Voûtes à nervures Manuélines. Le caractère innovant de João de Castilho”, concluida em 2014. Analisamos a informação bibliográfica; identificamos a origem e influência da tipologia de combados usada em Setúbal, a partir de um inventário de quase mil abóbadas europeias; analisamos a geometria e os métodos de conceção e de construção das abóbadas, a partir de levantamentos arquitetónicos e com base nos métodos indicados por Hernán Ruiz (1500-1569) e Rodrigo Gil de Hontañón (1500-1577). Os resultados contribuem para a questão histórica relativa à atribuição da abóbada da capela-mor da igreja de Setúbal. Confirmam a sua semelhança com a abóbada da Sé de Braga, nomeadamente no traçado e no método de construção, características espanholas e de João de Castilho. A metodologia usada para a análise arquitetónica, contribui para questões técnicas e de interesse internacional, relativas ao método de traçado e de construção de abóbadas góticas.info:eu-repo/semantics/acceptedVersio