926 resultados para Blocos de Alvenaria
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Uma das maiores causas de degradao dos revestimentos a presena de sais solveis, tanto nas zonas costeiras como nas zonas continentais. Estes sais podem ter origens distintas, tais como: humidade ascensional, nevoeiro salino, inundaes ou ainda estarem presentes nos prprios materiais, como o caso da utilizao de areias mal lavadas. O local onde os sais cristalizam dependente do tipo de transporte entre a alvenaria e o revestimento, assim como da severidade da envolvente ambiental (temperatura e humidade relativa). Com esta tese pretende-se desenvolver revestimentos de substituio compatveis, eficazes e durveis para alvenarias antigas sujeitas ao severa da gua (humidade ascensional atravs das fundaes com elevada concentrao de NaCl); desenvolver ensaios de envelhecimento acelerado baseados em ciclos de dissoluo e cristalizao que permitam simular a ao severa da gua; perceber a influncia de revestimentos com caratersticas extremas de permeabilidade ao vapor de gua aplicados nas duas faces do mesmo suporte (argamassas de cimento e resina versus argamassas de cal), e sujeitos ao severa da gua; perceber a influncia de vrios fatores, tais como : rasgos verticais contnuos executados no emboo e a utilizao de hidrfugo no reboco no desempenho dos vrios sistemas de revestimento desenvolvidos, quando sujeitos ao severa da gua;; utilizar a remoo eletrocintica de sais, em provetes simulando a influncia da alvenaria e dos revestimentos, com o objetivo de reduzir a sua concentrao de NaCl, para que no futuro possa ser aplicado de forma eficaz em paredes de edifcios antigos, enquanto ao de manuteno, e desta forma aumentar a durabilidade dos revestimentos. Para atingir os objetivos descritos, foram considerados: i) o desenvolvimento de provetes que permitam considerar os sistemas de revestimento desenvolvidos nesta tese e o suporte, e que simulem uma alvenaria revestida em ambas as faces, e com os quais seja possvel a simulao da ao severa da gua em laboratrio e, ii) o desenvolvimento ciclos de dissoluo e cristalizao numa parede de grandes dimenses existente em laboratrio, que permitam simular a ao severa da gua em condies to reais quanto possvel. O objetivo final deste estudo o desenvolvimento de um revestimento de substituio denominado emboo ventilado para paredes de edifcios antigos com revestimentos degradados devido presena de humidade ascensional e sais solveis. Pretende-se que este sistema de revestimento, composto por duas camadas de revestimento (camada base e reboco), seja compatvel, durvel e eficaz, e que funcione como um sistema de acumulao no qual os sais cristalizem na camada base do sistema de revestimento (executada com rasgos verticais) e no na alvenaria ou na camada exterior.
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Esta tese investiga a caracterizao (e modelao) de dispositivos que realizam o interface entre os domnios digital e analgico, tal como os buffers de sada dos circuitos integrados (CI). Os terminais sem fios da atualidade esto a ser desenvolvidos tendo em vista o conceito de rdio-definido-por-software introduzido por Mitola. Idealmente esta arquitetura tira partido de poderosos processadores e estende a operao dos blocos digitais o mais prximo possvel da antena. Neste sentido, no de estranhar que haja uma crescente preocupao, no seio da comunidade cientfica, relativamente caracterizao dos blocos que fazem o interface entre os domnios analgico e digital, sendo os conversores digital-analgico e analgico-digital dois bons exemplos destes circuitos. Dentro dos circuitos digitais de alta velocidade, tais como as memrias Flash, um papel semelhante desempenhado pelos buffers de sada. Estes realizam o interface entre o domnio digital (ncleo lgico) e o domnio analgico (encapsulamento dos CI e parasitas associados s linhas de transmisso), determinando a integridade do sinal transmitido. Por forma a acelerar a anlise de integridade do sinal, aquando do projeto de um CI, fundamental ter modelos que so simultaneamente eficientes (em termos computacionais) e precisos. Tipicamente a extrao/validao dos modelos para buffers de sada feita usando dados obtidos da simulao de um modelo detalhado (ao nvel do transstor) ou a partir de resultados experimentais. A ltima abordagem no envolve problemas de propriedade intelectual; contudo raramente mencionada na literatura referente caracterizao de buffers de sada. Neste sentido, esta tese de Doutoramento foca-se no desenvolvimento de uma nova configurao de medio para a caracterizao e modelao de buffers de sada de alta velocidade, com a natural extenso aos dispositivos amplificadores comutados RF-CMOS. Tendo por base um procedimento experimental bem definido, um modelo estado-da-arte extrado e validado. A configurao de medio desenvolvida aborda no apenas a integridade dos sinais de sada mas tambm do barramento de alimentao. Por forma a determinar a sensibilidade das quantias estimadas (tenso e corrente) aos erros presentes nas diversas variveis associadas ao procedimento experimental, uma anlise de incerteza tambm apresentada.
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The promise of a truly mobile experience is to have the freedom to roam around anywhere and not be bound to a single location. However, the energy required to keep mobile devices connected to the network over extended periods of time quickly dissipates. In fact, energy is a critical resource in the design of wireless networks since wireless devices are usually powered by batteries. Furthermore, multi-standard mobile devices are allowing users to enjoy higher data rates with ubiquitous connectivity. However, the bene ts gained from multiple interfaces come at a cost in terms of energy consumption having profound e ect on the mobile battery lifetime and standby time. This concern is rea rmed by the fact that battery lifetime is one of the top reasons why consumers are deterred from using advanced multimedia services on their mobile on a frequent basis. In order to secure market penetration for next generation services energy e ciency needs to be placed at the forefront of system design. However, despite recent e orts, energy compliant features in legacy technologies are still in its infancy, and new disruptive architectures coupled with interdisciplinary design approaches are required in order to not only promote the energy gain within a single protocol layer, but to enhance the energy gain from a holistic perspective. A promising approach is cooperative smart systems, that in addition to exploiting context information, are entities that are able to form a coalition and cooperate in order to achieve a common goal. Migrating from this baseline, this thesis investigates how these technology paradigm can be applied towards reducing the energy consumption in mobile networks. In addition, we introduce an additional energy saving dimension by adopting an interlayer design so that protocol layers are designed to work in synergy with the host system, rather than independently, for harnessing energy. In this work, we exploit context information, cooperation and inter-layer design for developing new energy e cient and technology agnostic building blocks for mobile networks. These technology enablers include energy e cient node discovery and short-range cooperation for energy saving in mobile handsets, complemented by energy-aware smart scheduling for promoting energy saving on the network side. Analytical and simulations results were obtained, and veri ed in the lab on a real hardware testbed. Results have shown that up to 50% energy saving could be obtained.
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Slender masonry structures are distributed all over the world and constitute a relevant part of the architectural and cultural heritage of humanity. Their protection against earthquakes is a topic of great concern among the scientific community. This concern mainly arises from the strong damage or complete loss suffered by this group of structures due to catastrophic events and the need and interest to preserve them. Although the great progress in technology, and in the knowledge of seismology and earthquake engineering, the preservation of these brittle and massive structures still represents a major challenge. Based on the research developed in this work it is proposed a methodology for the seismic risk assessment of slender masonry structures. The proposed methodology was applied for the vulnerability assessment of Nepalese Pagoda temples which follow very simple construction procedure and construction detailing in relation to seismic resistance requirements. The work is divided in three main parts. Firstly, particular structural fragilities and building characteristics of the important UNESCO classified Nepalese Pagoda temples which affect their seismic performance and dynamic properties are discussed. In the second part the simplified method proposed for seismic vulnerability assessment of slender masonry structures is presented. Finally, the methodology proposed in this work is applied to study Nepalese Pagoda temples, as well as in the efficiency assessment of seismic performance improvement solution compatible with original cultural and technological value.
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The massive adoption of sophisticated mobile devices and applications led to the increase of mobile data in the last decade, which it is expected to continue. This increase of mobile data negatively impacts the network planning and dimension, since core networks are heavy centralized. Mobile operators are investigating atten network architectures that distribute the responsibility of providing connectivity and mobility, in order to improve the network scalability and performance. Moreover, service providers are moving the content servers closer to the user, in order to ensure high availability and performance of content delivery. Besides the e orts to overcome the explosion of mobile data, current mobility management models are heavy centralized to ensure reachability and session continuity to the users connected to the network. Nowadays, deployed architectures have a small number of centralized mobility anchors managing the mobile data and the mobility context of millions of users, which introduces issues related to performance and scalability that require costly network mechanisms. The mobility management needs to be rethought out-of-the box to cope with atten network architectures and distributed content servers closer to the user, which is the purpose of the work developed in this Thesis. The Thesis starts with a characterization of mobility management into well-de ned functional blocks, their interaction and potential grouping. The decentralized mobility management is studied through analytical models and simulations, in which di erent mobility approaches distinctly distribute the mobility management functionalities through the network. The outcome of this study showed that decentralized mobility management brings advantages. Hence, it was proposed a novel distributed and dynamic mobility management approach, which is exhaustively evaluated through analytical models, simulations and testbed experiments. The proposed approach is also integrated with seamless horizontal handover mechanisms, as well as evaluated in vehicular environments. The mobility mechanisms are also speci ed for multihomed scenarios, in order to provide data o oading with IP mobility from cellular to other access networks. In the pursuing of the optimized mobile routing path, a novel network-based strategy for localized mobility is addressed, in which a replication binding system is deployed in the mobility anchors distributed through the access routers and gateways. Finally, we go further in the mobility anchoring subject, presenting a context-aware adaptive IP mobility anchoring model that dynamically assigns the mobility anchors that provide the optimized routing path to a session, based on the user and network context. The integration of dynamic and distributed concepts in the mobility management, such as context-aware adaptive mobility anchoring and dynamic mobility support, allow the optimization of network resources and the improvement of user experience. The overall outcome demonstrates that decentralized mobility management is a promising direction, hence, its ideas should be taken into account by mobile operators in the deployment of future networks.
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This dissertation introduces several methodological approaches which integrate a proposed coastal management model in an interdisciplinary perspective. The research presented herein is displayed as a set of publications comprising different thematic outlooks. The thesis develops an integrated coastal geoengineering approach which is intrinsically linked to the studied maritime environments. From sandy coasts and marine works to rocky platforms and sea cliffs, this study includes field work between Caminha Figueira da Foz (NW Portugal) and Galicia (NW Spain). The research also involves an analysis and geological-geotechnical characterisation of natural rock (armourstone) and artificial units (concrete blocks) applied to coastal structures. The main goal is to contribute to the characterisation and re-evaluation of georesources and to determine armourstone suitability and availability from its source (quarry). It was also important to diagnose the geomaterials in situ concerning their degradation/deterioration level on the basis of the current status of the coastal protection works in order to facilitate more efficient monitoring and maintenance, with economic benefits. In the rocky coast approach the coastal blocks were studied along the platform, but also the geoforms were studied from a coastal morphodynamics point of view. A shoreline evolution analysis was developed for sandy coasts through Digital Shoreline Analysis System (DSAS) extension. In addition, the spatial and statistical analysis applied to sea cliffs allowed the establishment of susceptibility zones to erosion and hazardous areas. All of these studies have different purposes and results however, there is a common denominator GIS mapping. Hence, apart from the studied coastal environment, there is an integrated system which includes a sequence of procedures and methodologies that persisted during the research period. This is a step forward in the study of different coastal environments by using almost the same methodologies. This will allow the characterisation, monitoring and assessment of coastal protection works, rocky coasts, and shore platforms. With such data, it is possible to propose or recommend strategies for coastal and shoreline management based on several justifications in terms of social, economic, and environmental questions, or even provide a GIS-based planning support system reinforced by geocartographic decisions. Overall the development of the applied cartography embraces six stages which will allow the production of detailed maps of the maritime environment: (1) high-resolution aerial imagery surveys; (2) visual inspection and systematic monitoring; (3) applied field datasheet; (4) in situ evaluation; (5) scanline surveying; and (6) GIS mapping. This thesis covers fundamental matters that were developed over the course of scientific publication and as a consequence they represent the results obtained and discussed. The subjects directly related to the thesis architecture are: (i) cartography applied to coastal dynamics (including an art historical analysis as a tool to comprehend the coastal evolution and the littoral zone); (ii) georesources assessment (the role of cartography in georesources zoning, assessment and armourstone durability); (iii) coastal geoengineering applications and monitoring (Espinho pilot site in NW Portugal as an experimental field); (iv) rocky coast and shore platform studies and characterisation; (v) sandy and mixed environment approaches; (vi) coastal geosciences GIS mapping and photogrammetric surveying (coastal geoengineering); and (vii) shoreline change mapping and coastal management strategies (the CartGalicia Project as an example NW Spain). Finally, all of these thematic areas were crucial to generate the conceptual models proposed and to shape the future of integrated coastal coastal geoengineering management.
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Tese de dout., Engenharia Electrnica e Computao, Faculdade de Cincias e Tecnologia, Univ. do Algarve, 2003
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Relatrio da Prtica de Ensino Supervisionada, Ensino das Artes Visuais no 3 Ciclo do Ensino Bsico e no Ensino Secundrio, Universidade de Lisboa, 2013
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Relatrio da Prtica de Ensino Supervisionada, Ensino de Artes Visuais, Universidade de Lisboa, 2013
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Relatrio da Prtica de Ensino Supervisionada, Ensino de Ingls e de Espanhol no 3 ciclo do Ensino Bsico e no Ensino Secundrio, Universidade de Lisboa, 2013
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Tese de doutoramento, Farmcia (Qumica Farmacutica e Teraputica), Universidade de Lisboa, Faculdade de Farmcia, 2014
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Relatrio da Prtica de Ensino Supervisionada, Mestrado em Ensino de Fsica e Qumica no 3 ciclo do Ensino Bsico e no Ensino Secundrio, Universidade de Lisboa, 2014
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Relatrio da prtica de ensino supervisionada, Mestrado em Ensino de Informtica, Universidade de Lisboa, Instituto de Educao, 2014
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Relatrio da Prtica de Ensino Supervisionada, Mestrado em Ensino da Fsica e da Qumica no 3 ciclo do Ensino Bsico e no Ensino Secundrio, Universidade de Lisboa, 2014
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Tese de mestrado, Cincias do Sono, Faculdade de Medicina, Universidade de Lisboa, 2016
