Caracterização experimental de díodos a temperaturas criogénicas

Dissertação para obtenção do Grau de Mestre em Engenharia Electrotécnica e de Computadores

Liaisons dangereuses, conservation of modern and contemporary art: a study of the synthetic binding media in Portugal

Dissertação apresentada para obtenção do Grau de Doutor em Conservação e Restauro, especialidade de Ciências da Conservação, pela Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia

Desperdício de medicamentos em ambiente hospitalar : identificação dos pontos críticos no circuito, impacto no consumo de recursos e estratégias de controlo

RESUMO - Numa época de constrangimento orçamental, os hospitais do SNS vêm-se na obrigação de melhorar a eficiência de utilização dos recursos disponíveis, por forma a contribuir para o seu equilíbrio financeiro. Cabe a cada prestador analisar a sua posição, avaliar as suas oportunidades e adoptar estratégias que a curto, médio ou longo prazo se traduzam numa efetiva melhoria na eficiência. A análise e o controlo do desperdício associado à prestação de cuidados de saúde apresentam-se, globalmente, como uma dessas oportunidades. Neste trabalho são exploradas oportunidades de redução de desperdício em medicamentos, numa perspectiva meramente operacional, a nível das funções desempenhadas pelos Serviços Farmacêuticos (SF). No hospital em estudo acompanhou-se as diferentes linhas de produção dos SF, nomeadamente as tarefas envolvidas no processo de Distribuição Individual Diária em Dose Unitária, na distribuição de medicamentos para o Serviço de Urgências (SU) e na preparação de citotóxicos e imunomoduladores para o Hospital de Dia de Oncologia. Durante o ano de 2013, os SF devolveram aos fornecedores 0,07% e abateram 0,05% da despesa em medicamentos. A análise dos erros de medicação registados reflete o tipo de distribuição adotado para a maioria dos serviços de internamento do hospital. As melhorias encontradas a este nível passam pelo reforço de recursos humanos a desempenhar as tarefas de dispensa de medicamentos mas também pela implementação de uma cultura de registo de erros e acidentes, baseada no sistema de informação, para que se consiga quantificar o desperdício associado e agir com vista à optimização do circuito. A relação entre o método de distribuição adotado para o SU e a utilização do medicamento neste serviço foi apenas investigada para os medicamentos de registo individual de administração. Foi determinado um índice de eficiência de utilização de 67,7%, entre o dispensado e o administrado. Às discrepâncias encontradas está associado um custo de 32 229,6 € para o ano de 2013. Constatou-se também que, a nível do consumo de citotóxicos e imunomoduladores houve, durante o mês de abril de 2013, um índice de desperdício médio de 14,7%, entre o prescrito e o consumido, que se traduziu num custo do desperdício mensal de 13 070,9 €. Com base no desperdício mensal estimou-se que o desperdício anual associado à manipulação de citotóxicos e imunomoduladores deverá corresponder a 5,5% da despesa anual do serviço com estes medicamentos. Não obstante as limitações encontradas durantes o trabalho, e parte do desperdício apurado ser inevitável, demonstrou-se que o desperdício em medicamentos pode traduzir-se numa fatia não negligenciável mas controlável da despesa do hospital em estudo. No seguimento do seu conhecimento, a sua contenção pode ter um impacto na redução de despesa a curto-médio prazo, sem a necessidade de racionamento da utilização de medicamentos e sem alterar os padrões de qualidade assistencial exigidos pela tutela e pelos doentes. Por último, são apresentadas recomendações para a redução do desperdício em medicamentos, adequadas a cada uma das dimensões analisadas.

The Portuguese contemporary art as an investment

In this paper we investigate what drives the prices of Portuguese contemporary art at auction and explore the potential of art as an asset. Based on a hedonic prices model we construct an Art Price Index as a proxy for the Portuguese contemporary art market over the period of 1994 to 2014. A performance analysis suggests that art underperforms the S&P500 but overperforms the Portuguese stock market and American Government bonds. However, It does it at the cost of higher risk. Results also show that art as low correlation with financial markets, evidencing some potential in risk mitigation when added to traditional equity portfolios.

The perfect paint in modern art conservation: a comparative study of 21st century vinyl emulsions

Contemporary painting places, and will continue to place, several questions about its meaning, its chemical nature, its durability and the best way to preserve it. This research aims at putting together comprehensive data on vinyl based paints, including their components, their properties, their aging behavior and their response to selected cleaning products. In this project degradation mechanisms of vinyl binders and formulations used in the 20th and 21st century were studied. Stability over time of selected vinyl polymers was assessed through natural indoor and artificially aging. The objective was to enhance knowledge and understanding of vinyl emulsion formulations and their performance over time. Overall conservation state of pictorial layers namely, adhesion, cohesion and discoloration of selected case studies from the Portuguese artist Julião Sarmento (b.1948) was correlated with the observed molecular level changes studied in laboratory experiments. Sarmento’s paintings were chosen due to conservation concerns (discoloration) on some of his works from the 90’s. Besides, research was carried out to start increasing the knowledge of what can be expected of PVAc based paints in terms of response to conservation treatments namely, surface cleaning. Artificial aging showed that the most recent formulations which are based on a poly(vinyl acetate), poly(vinyl chloride) and polyethylene terpolymer are less stable when compared to some homopolymer formulations. From the four pigments studied, titanium dioxide rutile and a carbon based black proved to be stabilizers for both types of polymer. The mixture lithopone plus calcium carbonate has showed to have a photocatalytic effect on the binders. The studied paintings showed to be in an overall good state of conservation except for the paintings created in the 90’s with white glue and a mixture of white lithoponeand calcium carbonate. Discoloration of this white paint seems to be irreversible and ongoing and is still a major concern. The disapearance of the plasticizer was the only change detected. The current works created by Sarmento are expected to be more stable as they were painted using the rutile titanium dioxide. Immersion/cleaning tests showed that vinyl based paints can be susceptible to water and organic solvents like ethanol as some evidences point to the removal/diffusion of additives from the paint. The observations made point to the need to further proceed in this research field.

Máquina síncrona em regime transitório após brusco curto-circuito no estator

A partir das equações de Park pretende-se modelar a máquina de rotor de pólos salientes com enrolamentos amortecedores e prever o seu funcionamento em regime transitório. A dissertação tem como objectivo estabelecer a teoria generalizada da máquina síncrona em regime transitório e proceder a ensaios laboratoriais a fim de obter as correntes de curto-circuito trifásico simétrico, difásico e fase-neutro. A partir destes ensaios é possível obter as constantes de tempo e reactâncias transitórias e subtransitórias do alternador, cujo conhecimento é importante para o dimensionamento dos disjuntores de protecção do alternador e toda a carga a jusante.

Concurrent tabling

In the past few years Tabling has emerged as a powerful logic programming model. The integration of concurrent features into the implementation of Tabling systems is demanded by need to use recently developed tabling applications within distributed systems, where a process has to respond concurrently to several requests. The support for sharing of tables among the concurrent threads of a Tabling process is a desirable feature, to allow one of Tabling’s virtues, the re-use of computations by other threads and to allow efficient usage of available memory. However, the incremental completion of tables which are evaluated concurrently is not a trivial problem. In this dissertation we describe the integration of concurrency mechanisms, by the way of multi-threading, in a state of the art Tabling and Prolog system, XSB. We begin by reviewing the main concepts for a formal description of tabled computations, called SLG resolution and for the implementation of Tabling under the SLG-WAM, the abstract machine supported by XSB. We describe the different scheduling strategies provided by XSB and introduce some new properties of local scheduling, a scheduling strategy for SLG resolution. We proceed to describe our implementation work by describing the process of integrating multi-threading in a Prolog system supporting Tabling, without addressing the problem of shared tables. We describe the trade-offs and implementation decisions involved. We then describe an optimistic algorithm for the concurrent sharing of completed tables, Shared Completed Tables, which allows the sharing of tables without incurring in deadlocks, under local scheduling. This method relies on the execution properties of local scheduling and includes full support for negation. We provide a theoretical framework and discuss the implementation’s correctness and complexity. After that, we describe amethod for the sharing of tables among threads that allows parallelism in the computation of inter-dependent subgoals, which we name Concurrent Completion. We informally argue for the correctness of Concurrent Completion. We give detailed performance measurements of the multi-threaded XSB systems over a variety of machines and operating systems, for both the Shared Completed Tables and the Concurrent Completion implementations. We focus our measurements inthe overhead over the sequential engine and the scalability of the system. We finish with a comparison of XSB with other multi-threaded Prolog systems and we compare our approach to concurrent tabling with parallel and distributed methods for the evaluation of tabling. Finally, we identify future research directions.

Pattern operators for grid

The definition and programming of distributed applications has become a major research issue due to the increasing availability of (large scale) distributed platforms and the requirements posed by the economical globalization. However, such a task requires a huge effort due to the complexity of the distributed environments: large amount of users may communicate and share information across different authority domains; moreover, the “execution environment” or “computations” are dynamic since the number of users and the computational infrastructure change in time. Grid environments, in particular, promise to be an answer to deal with such complexity, by providing high performance execution support to large amount of users, and resource sharing across different organizations. Nevertheless, programming in Grid environments is still a difficult task. There is a lack of high level programming paradigms and support tools that may guide the application developer and allow reusability of state-of-the-art solutions. Specifically, the main goal of the work presented in this thesis is to contribute to the simplification of the development cycle of applications for Grid environments by bringing structure and flexibility to three stages of that cycle through a commonmodel. The stages are: the design phase, the execution phase, and the reconfiguration phase. The common model is based on the manipulation of patterns through pattern operators, and the division of both patterns and operators into two categories, namely structural and behavioural. Moreover, both structural and behavioural patterns are first class entities at each of the aforesaid stages. At the design phase, patterns can be manipulated like other first class entities such as components. This allows a more structured way to build applications by reusing and composing state-of-the-art patterns. At the execution phase, patterns are units of execution control: it is possible, for example, to start or stop and to resume the execution of a pattern as a single entity. At the reconfiguration phase, patterns can also be manipulated as single entities with the additional advantage that it is possible to perform a structural reconfiguration while keeping some of the behavioural constraints, and vice-versa. For example, it is possible to replace a behavioural pattern, which was applied to some structural pattern, with another behavioural pattern. In this thesis, besides the proposal of the methodology for distributed application development, as sketched above, a definition of a relevant set of pattern operators was made. The methodology and the expressivity of the pattern operators were assessed through the development of several representative distributed applications. To support this validation, a prototype was designed and implemented, encompassing some relevant patterns and a significant part of the patterns operators defined. This prototype was based in the Triana environment; Triana supports the development and deployment of distributed applications in the Grid through a dataflow-based programming model. Additionally, this thesis also presents the analysis of a mapping of some operators for execution control onto the Distributed Resource Management Application API (DRMAA). This assessment confirmed the suitability of the proposed model, as well as the generality and flexibility of the defined pattern operators

Services innovation and economic performance: An analysis at the firm

In this paper we estimate a model linking innovation effort and economic performance, along the lines of the Mairesse and Mohnen (2003) model. We examine this relationship in the context of services sectors instead of Research and Development intensive manufacturing sectors. Much effort has already been made to explore the innovation-performance relationship for manufacturing sectors but it is still much understudied for services, particularly for Portugal. In this paper we aim to take a step in fulfilling this gap. We use new firm level data for ten services sectors from the Second Community Innovation Survey of Portugal, to estimate the model.

Orchestration of heterogeneous middleware services and its application to a comand and control platform

MSC Dissertation in Computer Engineering

Case study: Estratégia de aplicação de ferramentas de apoio à gestão da performance humana em ambientes Lean

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do Grau de Mestre em Engenharia Industrial

Framework for a business interoperability quotient measurement model

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova da Lisboa para obtenção do grau de Mestre em Engenharia e Gestão Industrial (MEGI)

High-performance flexible hybrid field-effect transistors based on cellulose fiber paper

IEEE Electron Device Letters, VOL. 29, NO. 9,

Análise do balanço entre sequestro e emissão de CO2 resultante do circuito de produção e consumo de biomassa florestal numa central de co-geração

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Bioenergia

Effect of fungal colonization on mechanical performance of cork

The industrialization of traditional processes relies on the scientific ability to understand the empirical evidence associated with traditional knowledge. Cork manufacturing includes one operation known as stabilization, where humid cork slabs are extensively colonized by fungi. The implications of fungal growth on the chemical quality of cork through the analysis of putative fungal metabolites have already been investigated. However, the effect of fungal growth on the mechanical properties of cork remains unexplored. This study investigated the effect of cork colonization on the integrity of the cork cell walls and their mechanical performance. Fungal colonization of cork by Chrysonilia sitophila, Mucor plumbeus Penicillium glabrum, P. olsonii, and Trichoderma longibrachiatum was investigated by microscopy. Growth occurred primarily on the surface of the cork pieces, but mycelium extended deeper into the cork layers, mostly via lenticular channels and by hyphal penetration of the cork cell wall. In this first report on cork decay in which specific correlation between fungal colonization and mechanical proprieties of the cork has been investigated, all colonizing fungi except C. sitophila, reduced cork strength, markedly altering its viscoelastic behaviour and reducing its Young’s modulus.