Low-span lightweight membranes in housing : environmental and structural potentialities

Textile membranes are usually used to cover big spans with complex geometries, using the special properties of the Hypar (Hyperbolic paraboloid). However it is possible to use membranes on small external façades and coverings, with low spans, not only as sandwich panels, but also as a junction of small Hypar modules. Like this the mechanical special properties of this geometry can be well explored, allowing a very small weight and thus a good environmental performance, compared to conventional façade and covering solutions, on a comparable thickness. Apart from this, the research on membrane materials for thermal regulation, allows to extend its possibilities in order to fulfill contemporary demands of comfort. In the outer skin, architectural membranes can be used as passive systems, for heating (promoting greenhouse effect) and cooling (shading or even evaporative cooling), as well as allowing some transparency, and thus also natural lighting, specially important on south and north facades. A prototype based on this concept is now under construction on Azurém Campus of the University of Minho, adapted for research on external façade systems as well as for coverings of small spans. This solution will be presented from its mechanical and structural concept, as well as its embodied energy and thermal / lighting performance, in comparison with conventional systems

Membranes for functional conditioning: report on the design and construction of two active bending structures incorporating reused materials

This paper describes the design and assembling process of two experimental structures located in the University of Minho’s School of Architecture, Art and Design, carried out between 2020 and 2022. Both were designed using the concept of active bending, assured by poles made of Glass Fibre Reinforced Polymer (GFRP) as supporting elements to membrane mesh made in PVC coated polyester. The assembling process allowed participants to experiment all the steps related with the design and construction of membrane structures with active bending elements, considering their advantages and disadvantages. The ability of membrane structures for the functional conditioning of the built environment was explored in two different scenarios, showing that they can be adequate both in outdoor as in indoor contexts. The idea of learning by doing served as the foundation for the pedagogical practices used. Each practice was discussed and tailored to the specific situation, regarding the conditions of the site, the participants involved and the functional conditioning requirements of each space.The author wants to acknowledge all the colleagues, students and companies involved in the design and construction of the models and structures presented. The author also acknowledges support from the Project Lab2PT - Landscapes, Heritage and Territory laboratory - UIDB/04509/2020 through the FCT - Fundação para a Ciência e a Tecnologi

Azores EcoBlue

Marine litter is one of the main environmental problems facing the Ocean and the Azores archipelago is not immune to this global issue. Considering the socio-economic role of the fishing sector in the Azores, the Azores EcoBlue project aims to use and develop new and innovative raw materials, transforming the marine litter resulting from this activity, which is currently little or not valued in this Region, into a “supplier” market of excellence. Together with local communities, it aims to collect the litter and waste from fishing activity and proceed with its characterization, quantification and processing, the results of which will be presented on a platform for sharing statistical data. Subsequently, through scientific studies, it aims to develop yarns and fibers that can be transformed and used as raw material in fabrics and insulation blankets for use in the construction sector. A prototype model of an Ecolodge with the new products will also be created. The project will benefit consumers looking for efficient eco-design solutions, as it will offer exclusive recycled eco-design products. The accommodation sector will also benefit from the ecolodge model/prototype to be developed, and other regions can replicate this business model, applicable on a global scale, where marine litter is a reality. This presentation shows up some of the contributions of University of Minho in relation to sustainable materials for buildings developed within this project

Sustainable housing with mixedweight strategy : a case study

Prova tipográfica (In Press)The aim of this research work is to demonstrate how an innovative mixedweight solution can lead to achieve more sustainable housing constructions, having in mind that functional aspects related with comfort - thermal, acoustical and natural illumination should be safeguarded. The integrated accomplishment of all these aspects is difficult and not easily predictable. That’s why, for this comparative study, two Test Cells were built and monitored. The proposed mixedweight strategy was evaluated on a Test Cell made with a heavyweight central area, theoretically conceived to lodge the resting areas of a house - bedrooms, bathroom and living room. North and South envelope façades, pavement and covering are lightweight and lodge the less protected areas, destined for working (office, dining room and kitchen) and a corridor / sunspace, respectively. These compartments also take the role of thermal and acoustical barriers to the resting zone. This mixedweight strategy allowed to significantly less environmental cost in comparison to a conventional heavyweight constructive solution using hollow brick and steel reinforced concrete evaluated on a Reference Test Cell and conceived in a monozone layout. The main aspects and results of this study are presented here.Fundação para a Ciência e a Tecnologia (FCT)

Functional assessment of lightweight construction solutions in view of sustainability

The amount of waste produced every year, the exhaustion of resources and the construction solutions currently used on construction may not be sustainable in the future. All these issues lead to the research of new construction techniques, the recycling of waste into use-ful materials, the re-use of construction materials, etc. Most of the new and innovative solutions arise from the general feeling that something should be done to change the conventional way of construction in order to give an answer to current society concerns: the reduction of energy con-sumption, the minimization of pollution problems, the maximisation of the use of renewable and/or recyclable materials, etc. The aim of this study is to evaluate the potentialities of using more lightweight construction solutions with respect to functional comfort criteria (thermal, acoustic and visual comfort) and to assess the relative merits of this type of construction in view of maximising sustainability. Beyond the structural behaviour of a building the demand of a bet-ter habitat requires also a good performance in terms of serviceability. In this work the perform-ance of lightweight construction solutions (optimized for reducing environmental impact) and conventional construction solutions were compared under the energy costs point of view (con-struction and heating). The acoustic performance was also studied, but just in order to achieve similar conditions, thus becoming not relevant to the purpose of this study.Fundação para a Ciência e a Tecnologia (FCT)

Efeito da utilização de probiótico sobre aspectos microbiológicos e parâmetros de qualidade da água e produtividade em viveiros de cultivo de camarão marinho Litopenaeus vannamei

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias. Programa de Pós-Graduação em AquiculturaFoi realizado estudo sobre a influência de um probiótico no cultivo de camarão (Litopenaeus vannamei) em viveiros de 1,25 ha em solo natural. Utilizou-se 2 tratamentos, sendo T1 com adição de probiótico e T2 sem adição. Realizado em triplicata e estocados com 21 juvenis de 3g/m². O experimento foi conduzido no município de Barra do Sul, SC, Brasil, durante um período de cultivo correspondendo aos meses de fevereiro á junho de 2004. Foram analisados os parâmetros microbiológicos: contagem padrão em placas de microrganismos mesófilos, bactérias acido lácticas, bolores e leveduras, vibrio sp e coliformes termotolerantes segundo metodologia APHA 2001. Entre os parâmetros físico-químicos: amônia, nitrito, nitrato. Os índices de produtividade foram comparados. As coletas para os parâmetros microbiológicos aconteceram a cada 15 dias. Determinação de amônia, nitrito e nitrato, 2 vezes por semana. Para parâmetros microbiológicos foi observada a variação da população ao longo do cultivo, não havendo diferenças entre tratamentos. Para físico-químicos as curvas ficaram sobrepostas para T1 e T2 evidenciando não haver influência do probiótico. Estes parâmetros mantiveram-se dentro de níveis adequados para a espécie durante todo o ciclo. Os resultados de produtividade para T1 foram: 2417,6 kg/ha (±478,82), TCA de 1,89 (±0,27), sobrevivência de 82,3% (±19,3), peso médio final de 14,2 gr (±0,72). Para T2 os resultados foram respectivamente: 2444,6 kg/ha (±498,53), TCA de 1,98 (± 0,22), sobrevivência de 83,0% (±14,73) e peso médio final de 13,8 gr (±1,58), não mostrando diferença estatística. Observou-se, nas condições do teste, que o probiótico não influenciou qualquer dos parâmetros medidos

Embodied carbon and economic cost analysis of a contemporary house design using local and reused materials

This paper presents a house design that uses adobe in the walls and wood in the roof, a mixed building system that vernacular houses in the region where it is located already use, however it presents a contemporary strategy based on less, more natural, reused, and local materials, implying also less transport. The environmental impact analysis of the Case Study was made considering the Embodied Carbon of the construction materials used and compared with conventional building systems. In spite of presenting a much lower embodied carbon than all the conventional solutions in comparison, it turns to be more expensive.FCT -Fundação para a Ciência e a Tecnologia(undefined

Certificate polygamy: a matter of trust

Tese de mestrado em Segurança Informática, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2011O acesso a serviços disponíveis na Internet expõe os utilizadores a diversos ataques, tal como o Man-in-the-Middle (MitM). As defesas para estes ataques, tais como autenticação mútua através de uma Public Key Infrastructure (PKI), baseiam-se em infra-estruturas complexas que os utilizadores não estão disponíveis para utilizar e suportar. A enorme aceitação de métodos de autenticação designados por “acto de fé” (leap-of-faith) ou “confiar na primeira utilização” (TOFU, trust-on-first-use), utilizado em implementações comuns de SSH e TLS/SSL, dão sinais claros da pré-disposição dos utilizadores em sacrificar a segurança em prol de uma melhor usabilidade. Aliás, este é um comportamento comum na vida quotidiana das pessoas. Se alguém se apresentar apenas com um cartão de visita, teremos tendência a confiar no seu conteúdo. Apenas desconfiaremos se, mais tarde, outra identificação for apresentada. Por outras palavras, confiamos nas primeiras credenciais apresentadas. Esta temática foi abordada por soluções como o Perspectives, que fornecem autenticação tipo SSH com sondagens através de múltiplos caminhos/acessos, descrito em [1]. Através da observação e recolha das chaves públicas observadas ao longo do tempo por servidores espalhados geograficamente, designados por Notários, o Perspectives impede muitos dos ataques possíveis num cenário de TOFU. Um utilizador pode solicitar o historial de chaves de um determinado serviço, comparando-o à chave oferecida na utilização corrente, e com esse historial tomar uma decisão mais informada quanto ao aceitar uma chave que não exista em cache. No entanto, o Perspectives assume um certificado por sítio, o que não é um pressuposto válido em muitos casos. Nesse caso, como pode o utilizador distinguir entre um certificado adicional introduzido pelo serviço a que está a aceder, e uma situação de ataque, em que o certificado está a ser fornecido pelo atacante? A presente tese endereça esta temática de poligamia de certificados, aumentando a visão dos Notários por forma a fornecer uma visão consolidada de diversos certificados. Adicionalmente, sugerimos alterações a alguns módulos do Perspectives, nomeadamente o módulo de sondagem (probing) for forma a lidar com questões tais como existência de mecanismos de caching acoplados aos serviços, pela utilização de, por exemplo, proxies.Users are vulnerable to attacks, such as Man-in-the-Middle (MitM) attack, whenever they resort to services in the Internet. Common defenses for these attacks, like mutual authentication based, for example, on a Public Key Infrastructure (PKI), rely on complex infra-structures that users are unwilling to support. Huge acceptance of simple methods like Trust-on-first-use (TOFU, also known as “leap-of-faith” authentication), employed by popular implementations of SSH and TLS/SSL, clearly indicate that users are prepared to sacrifice security for the sake of low-cost and more usable solutions. Moreover, this is a behavior that users are familiar with. If one meets a person who hands over some credentials, such as nickname, email address or even a business card, one will bind those credentials to that person in all future contacts, without initially asking for his or her ID. In other words, one trusts these credentials on the first time they are seen, and then uses them in all future interactions with that person. This topic has been addressed previously in solutions like Perspectives, which provides SSH-style Host Authentication with Multi-Path Probing, as described in [1]. By observing and collecting the server’s public keys over time, maintaining them in a set of geographically disperse servers known as “Notaries”, Perspective thwarts many of the attacks that are possible in a TOFU scenario. A user can download such records on demand, comparing them with the current key provided by the site being accessed. Although not secure to all attacks, users can make a more educated decision on accepting or rejecting each certificate. However, Perspectives assumes one certificate per site, which is a false assumption in some cases. So, how can users differentiate between a distinct, legitimate certificate provided by the site, and a fake certificate provided by an attacker? This thesis addresses this certificate polygamy issue, by enhancing the concept of the Notaries used in Perspectives, and provides a consistent view of a set of certificates to the user. Moreover, it suggests changes in modules like the probing module, to keep a clear and consistent observation of certificates, despite caching and reutilization made by components such as proxies. By allowing the user (or, by company policies) to fine tune some configuration parameters, the proposed solution will provide different levels of confidence to the observed server’s public keys, thus satisfying distinct levels of security, or user proficiency

Detection of Polyps via Shape and Appearance Modeling

Presented at the MICCAI 2008 Workshop on Computational and Visualization Challenges in the New Era of Virtual Colonoscopy, September 6, 2008, New York, USA.This paper describes a CAD system for the detection of colorectal polyps in CT. It is based on stochastic shape and appearance modeling of structures of the colon and rectum, in contrast to the data-driven approaches more commonly found in the literature it derives predictive stochastic models for the features used for classification. The method makes extensive use of medical domain knowledge in the design of the models and in the setting of their parameters. The proposed approach was successfully tested on challenging datasets acquired under a protocol with little colonic preparation; such protocol reduces patient discomfort and potentially improves compliance

Soil : a material for bio-compatible and eco-sustainable contemporary buildings

For long time the research has been addressing towards the creation and the design of “high tech” components for buildings with an high performance level in any kind of situation, so as to increase a global scale dissemination and thus to ensure large market segments and wide economic incomes. This logic, based on production of goods rather than on saving resources, has provided, upon time, a number of negative effects, such as the enlargement of prime matter and pure energy source consumption, but also a massification of the architecture language and a cultural flatting, by proposing stereotypes and formal layouts which were insensitive to site diversity and peculiarity. Studies made by the authors on the Mediterranean area, its construction traditions and its social and cultural differences, focused on the presence of various invariant lines, due to similar climatic, geological, historic and human conditions, has shown that, during the whole pre-industrial period, those conditions have led to the affirmation of such techniques and materials strictly depending on the peculiar characters of each zone. The various regions, even presenting the aforesaid common and distinctive features, can be often compared to each other, and provide hints for new research currents: “low-tech” materials, and thus at low embodied energy, by exploiting a number of local resources and various configuration solutions, allowing to obtain buildings that can adapt to different site conditions, and can provide a clear saving as far as both economic and environmental items are concerned. The Rammed Earth and Adobe, even in contemporary building applications, object of the proposed paper, have been demonstrated to own various relevant characters, since they appear as good compromises between thermal mass and insulation and hold good hygroscopic regulation capacity, by absorbing and giving back the humidity to the environment. These properties allow to achieve eco-efficiency aims, by limiting resource consumption, as well as bio-compatible objectives, by providing users’ health and comfort. Our research groups have carried out theoretical and experimental research that led to the chance of re-employing this traditional material within innovative products, thus considering soil, still nowadays, as a very good construction material. Case studies in Italy and Portugal are shown.(undefined