1,707 research outputs found

    Novas tecnologias construtivas com vista à sustentabilidade da construção

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    A dissertação aborda o conceito de “Sustentabilidade” na vertente da construção numa lógica de desenvolvimento da Indústria da Construção, face aos desafios ambientais, sociais e económicos que se colocam às empresas do sector neste início de século. Neste trabalho, pretende-se desmistificar o conceito “Construção Sustentável”, que devido a maus exemplos do passado – que se espera não virem a ser repetidos no presente e no futuro –, ficou quase irremediavelmente associado à construção em que o único objectivo era a diminuição do impacte ambiental, e em que se relegava para segundo plano, para além de outros, parâmetros tão importantes como a qualidade, durabilidade e custo. Este conceito perdeu e continua a perder credibilidade, devido às constantes manobras de marketing avançadas por algumas empresas do sector, que o associam erradamente aos seus produtos, numa lógica selvagem de maximização das vendas e dos lucros. A Indústria da Construção é um dos sectores económicos mais importantes em Portugal. Este sector continua, no entanto, a basear-se excessivamente nos sistemas construtivos tradicionais e na utilização de mão-de-obra não qualificada, sendo caracterizado por uma excessiva utilização de recursos naturais e energéticos. Tal situação causa grande impacte ambiental com igual potencialidade de vir a ser minorado. Neste trabalho são identificados os impactes ambientais da construção em geral e do sector dos edifícios em particular, sendo apresentadas algumas medidas e alguns exemplos de novas tecnologias construtivas e de outras – que resultam do ressurgimento e melhoramento de tecnologias já aplicadas há milhares de anos –, cuja aplicação e desenvolvimento visam alcançar os desígnios de uma Construção cada vez mais sustentável, que assente equilibradamente nos domínios ambiental, económico e social. No final deste trabalho, desenvolve-se uma metodologia que se espera adequada à avaliação relativa da sustentabilidade de soluções construtivas. Essa metodologia é, no final, aplicada a algumas soluções construtivas convencionais e não convencionais para pavimentos e paredes exteriores. Espera-se que as práticas aconselhadas com vista à minoração do impacte ambiental da construção, a metodologia desenvolvida e os resultados obtidos sirvam de base aos diversos intervenientes na Construção, nas tomadas de decisão que potenciem a realização de edifícios cada vez mais sustentáveis.This thesis embraces the “Sustainability” concept in the construction industry being the logical outcome the development of this industry that faces environmental, social and economical challenges, which enterprises have to consider in the beginning of this century. This thesis aims at demystifying the “Sustainable Construction” concept. Due to bad examples in the past, that hopefully will not be repeated in the present and future, this concept became almost irremediably associated to construction, in which the prime objective was reducing environmental impact leaving important parameters, like quality, durability and cost behind. This concept has lost and continues to loose credibility due to constant marketing manoeuvres by companies in this sector, that deceivingly associate this concept to their products, in order to, in a fiercely manner, maximize sales and profit. The construction industry is one of the most important economical sectors in Portugal. Nevertheless, this sector continues to base itself on traditional construction systems and unqualified workers, being characterized by excessive usage of natural and energetic resources. This situation causes great environmental impact with great potentialities to be reduced. This thesis identifies, in general, the environmental impacts in the construction industry, and particularly, in the building sector. A few measures and examples of new construction technologies and others are also presented, that are the result of technological renewal and improvement of building technologies, some of them, already applied thousands of years ago. The development and application of these technologies aim at a construction, more and more sustainable, that settles evenly on environmental, economical and social domains. A methodology, that is expected to be adequate to validate the sustainability of construction solutions, is presented at the end. This methodology is then applied to some conventional and non-conventional solutions of pavements and exterior walls. It is hoped that the practices approached, the methodology developed and the results obtained, may serve as a basis for the various construction intervenients, in the decision making process, in accomplishing buildings more sustainable

    Optimization of the sustainability during the refurbishment operation of a residential building

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    Most of the existing buildings have high resources consumption and low indoor environmental quality, leading to the unsustainability of the built environment. Being aware of this reality and based in the European goal to achieve Nearly-Zero Energy consumption standard in buildings, it is urgent to define guidelines that could support the sustainable refurbishment design since the earlier stages. This paper intends to illustrate the process of sustainable building refurbishment, supported by different guidelines applied to a case study. To achieve this goal the definition and evaluation of a group of procedures to be implemented, and a cost-benefit analysis applied to a case study was performed, having as final goal its sustainability optimization

    Optimization of the sustainability during the refurbishment design phase of a residential building using SBToolpt-H

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    As it has been observed along the years, the unsustainability of the built environment is due to the high resources consumption and low indoor air quality of the existing building stock. In order to support the sustainable refurbishment design of buildings, and to meet European goal to achieve nearly zero-energy consumption standards in buildings in 2020, it is urgent to define guidelines that can be implemented since the earlier stages of the design. This paper defines guidelines to optimize the sustainability of a residential building and presents the process of sustainable building refurbishment, applied to a case study. To achieve this goal, the definition and evaluation of a group of procedures to be implemented, and a cost-benefit analysis applied to a case study was performed

    Some examples of quantifier elimination and o-minimality

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    Tese de mestrado, Matemática, Universidade de Lisboa, Faculdade de ciências, 2021A structure with a total order that is dense without end-points is o-minimal if every definable set in dimension 1is a finite union of intervals and points. This notion materialized from observations that many of the proprieties of semialgebraic sets were deduced from very simple axioms, the ones that now define o-minimal structures. Indeed, o-minimality establishes strong regularity results of the definable sets. In this way, o-minimality can be viewed as a candidate to “topologie mod´er´ee” mentioned by Grothendieck in his Esquisse d’un programme. In the context of this dissertation, despite of its intrinsic richness, we study the property of quantifier elimination (abbreviated QE) as a way of proving o-minimality of a given structure. The goal of this dissertation was to study proofs of o-minimality and QE by studying a concrete example, the real closed ordered fields (abbreviated rcof). In Chapter 1, we begin by defining basic notions of first-order logic. We present some examples that will be useful later, such as the theory of rcof. We alude to the usefulness of different axiomatizations, such as the universal axiomatization, and simplifications of formulas, such as QE, that make the theories much more easier to understand. We present some criterias for a theory to admit QE. We present a geometrical perspective of the definable sets in general and the special case of o-minimality. In Chapter 2 we prove that the theory of rcof has QE. As a consequence we prove that every rcof is o-minimal. In Chapter 3 we study proprieties of o-minimal structures. In Chapter 4 we study the theory Tan of rcof with restricted analytic functions. We state that Tan has QE in the language Lan(1) and as a consequence we show that Tan admits an universal axiomatization in the language Lan(1; ( np)n=2;3;:::). In Chapter 5 we establish the result that every model of Tan can be seen as a substructure of a power series field R((t)). We use this fact to deduce key results concerning valuations on these structures and use these to prove that Tan(exp) admits QE and universal axiomatization, both in the language Lan(exp; log). In the last section of this chapter we begin by noting that, provided the theory admits QE, o-minimality is equivalent to regularity of the signal (whether it is greater, less or equal to zero) “at infinity” of the definable functions in one variable. This leads us to consider Hardy fields and using properties from these fields we prove that Tan(exp) is o-minimal

    The narratives of Juliana Huxtable and DeForrest Brown Jr.

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    Developed for the context of the V Narrative, Media, and Cognition Colloquium, this article focuses on the narratives generated by the works of Juliana Huxtable and DeForrest Brown Jr. With the intention of focusing on marginal productions, and using “Outwardly Coiling Context Collapse” by DeForrest Brown Jr. and “THERE ARE CERTAIN FACTS THAT CAN NOT BE DISPUTED” by Juliana Huxtable as case studies, this paper tries to understand what narratives try to be asserted, and how are they put in practice by these works. With the help of the contributions made by Patrícia Castello Branco and Levinas, the article concludes that the works of the artist’s move towards the creation of collective narratives with a clear social impact that simultaneously tries to steer away from a dominant historical narrative

    Sustainability assessment of an affordable residential building using the SBTool PT approach

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    This paper will present the sustainability assessment of an affordable residential building block using the SBTool PT – H approach. This building block resulted from a cooperative housing project that fulfils some of the priorities of high-performance and low environmental impact buildings and is internationally recognised as a good example of a sustainable project. The aim of this study is to verify the usefulness of the SBToolPT approach in promoting sustainable buildings that have lower life-cycle costs when compared to conventional ones

    Improving the design of a residential building using the Portuguese rating system SBToolPT

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    Construction affects all dimensions of sustainability (environment, society and economy) and therefore a sustainable building design has to cope with tens of criteria, most of them interrelated and partly contradictory. There are a great number of indicators and assessment tools that have been developed recently in order to evaluate the sustainability of buildings and urban settlements. Most of these tools are based on national standards, building codes and local methods of construction. Sustainable design of construction is only possible through a real methodological work. Sustainability assessment tools play an important role at this level, since they convert the sustainability issues into tangible goals while are used to collect and communicate the results of a sustainability assessment. This paper will present the role of the Portuguese Sustainability Rating System SBToolPT in promoting the sustainability of residential buildings.European Science Foundation

    Comparative assessment of exterior walls construction solutions’ sustainability

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    In this document a methodology for the comparative sustainability assessment of construction solutions will be approached. This work intends to be a contribution for the Con-struction in order to turn this industry more compatible with the sustainable development aims. The presented methodology will be applied to some conventional and non-conventional exterior walls construction solutions in order to find, inside the sample, the most sustainable solution.(undefined

    LCA database for portuguese building technologies

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    The aim of this paper is to present one solution to integrate more accurate environmental assessment methods in rating systems and that could be used to support the design teams’ decisions that aim the implementation of low impact building solutions. The solution is the development of a LCA database that is based in the EPD’s (Environmental Product Declarations) approach and that gathers the quantification of several environmental impact categories of the most common building solutions used in Portugal. This database is in continuous update and now covers about 50 building solutions for floors and exterior walls, 40 building materials and the impacts related to the use of 12 systems for acclimatization and hot water

    Princípios de racionalização energética na arquitectura vernacular

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    A arquitectura vernacular caracteriza-se por materializar formalmente uma pluralidade de condicionalismos – geográficos, climáticos e económicos – dos locais onde se insere. Estas implicações traduzem-se na diferenciação regional das estratégias usadas para mitigar os efeitos do clima. Apesar das condições de conforto destas construções não se enquadrarem nos parâmetros actuais, as estratégias adoptadas apresentam potencial de evolução e adaptação à contemporaneidade. Na altura, a fragilidade económica de grande parte das famílias levava à adopção de soluções pragmáticas e de profunda racionalização dos recursos disponíveis. O abandono destas abordagens arquitectónicas em detrimento de uma arquitectura universal baseada em materiais industriais, desarraigada do seu meio, levou a um tipo de construção muito dependente de energia para se garantirem os requisitos de conforto dos ocupantes. Num momento de viragem, promovido pelos actuais contextos ambiental e económico, em que se procuram formas de energia mais limpas e edifícios mais eficientes, é pertinente voltar ao passado para estudar e compreender estas formas de construção intrínsecas ao lugar, com o intuito de adaptar e desenvolver as suas mais-valias na descoberta das formas do futuro
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