Pesquisa e desenvolvimento de um sistema termoelétrico do tipo linear fresnel reflector

Dissertação para obtenção do Grau de Mestre em Energias Renováveis – Conversão Elétrica e Utilização Sustentável

Optimisation and design of post-tensioning anchorage corner blisters in concrete box girder bidges

The design of anchorage blisters of internal continuity post-tensioning tendons of bridges built by the cantilever method, presents some peculiarities, not only because they are intermediate anchorages but also because these anchorages are located in blisters, so the prestressing force has to be transferred from the blister the bottom slab and web of the girder. The high density of steel reinforcement in anchorage blisters is the most common reason for problems with concrete cast in situ, resulting in zones with low concrete compacity, leading to concrete crushing failures under the anchor plates. A solution may involve improving the concrete compression and tensile strength. To meet these requirements a high-performance fibre reinforced self-compacting mix- ture (HPFRC) was used in anchorage corner blisters of post-tensioning tendons, reducing the concrete cross-section and decreasing the reinforcement needed. To assess the ultimate capacity and the adequate serviceability of the local anchorage zone after reducing the minimum concrete cross-section and the confining reinforcement, specified by the anchorage device supplier for the particular tendon, load transfer tests were performed. To investigate the behaviour of anchorage blisters regarding the transmission of stresses to the web and the bottom slab of the girder, and the feasibility of using high performance concrete only in the blister, two half scale models of the inferior corner of a box girder existing bridge were studied: a reference specimen of ordinary reinforced concrete and a HPFRC blister specimen. The design of the reinforcement was based in the tensile forces obtained on strut-and-tie models. An experimental program was carried out to assess the models used in design and to study the feasibility of using high performance concrete only in the blister, either with casting in situ, or with precast solutions. A non-linear finite element analysis of the tested specimens was also performed and the results compared.

Internationalization of Papo D’anjo to Mexico

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

Haida Totem Poles: Reflections of a Society

The Haida were a First Nations group located on the Northwest Coast of Canada. They were exceptional wood carvers that produced various types of works, the most monumental of which were their totem poles. This dissertation analyses 26 of these open architectural structures, each of which belonged to one of the following five types: frontal, mortuary, memorial, house post, or corner post. Of the representations found on poles, 28 different figures were identified. However, individual poles were found to contain between one and fourteen different figures with frontal poles generally featuring the most. The predominant figures on the inventoried poles proved to be birds, humans, and bears. An iconographic structure of a tripartite character was detected that reflects the religious ideology of the Haida population with birds being featured at the top of the poles, humans in the middle, and bears at the lowest point. It also suggests the possible transition from a hunter-gatherer economy to a food producing economy.***********************************************************************************Os Haida foram um grupo das Primeiras Nações que habitaram a costa Noroeste do Canadá. Eram excepcionais escultores de madeira, tendo produzido variados tipos de artefactos, dos quais os totem poles eram os mais monumentais. Na presente dissertação são analisadas 26 dessas estruturas arquitectónicas de exterior, sendo que cada uma delas pertenceria a um dos seguintes cinco tipos: frontal, funerário, memorial, travemestra, ou postes de esquina. Das representações encontradas nos postes, foram individualizadas 28 figuras. No entanto, em postes isolados foi possível identificar entre uma e catorze figuras distintas, sendo os postes frontais os que apresentavam, geralmente, o maior número. A análise destes postes permitiu detectar uma estrutura iconográfica tripartida que reflectia a ideologia religiosa das populações Haida, representando-se as aves no topo, os humanos a meio, e os ursos na base dos postes. Por outro lado, foi possível sugerir, para estas populações, a transição de uma economia baseada na caça-recolecção para uma economia de produção alimentar.

Architecture and mosaics in recently discovered Palaeochristian basilicas

The excavations of the Dericik Early Christian Basilicas revealed the importance of the surrounding area of Bursa for understanding Early Christianity between the Late Roman and Early Byzantine periods. In the salvage excavations of 2001, the basic plan of the basilica (nave, narthex, presbyterium and apse) was revealed. The most important artefacts uncovered in that year were the mosaic pavements with geometric and plant ornaments and a grave located in the North Eastern corner of the church. The mosaic of the basilica was laid with the opus tessellatum technique on a thick mortar foundation with white, red, yellow, olive green and dark blue tesserae. A refrigerium scene is represented in the middle of the narthex mosaic. The mosaic in the centre of the nave is divided into parts, one of which with figures of birds inside octagons. In the transitional area between the nave and apse, three heavily damaged inscriptions have been conserved each of three or four lines, one of them indicating the wish of Epituchanos, diakôn, a church member.