Robustness of corroded reinforced concrete structures

Short Term Scienti c Mission, COST ACTION TU-0601

Synopsis of global scenario and forecasting surveys scenarios in risk habitat megacity (RHM)

The main objective of the paper is to provide a synopsis of global scenario and forecasting surveys. First, the paper will give an overview on existing global scenario and forecasting surveys and their specific scenario philosophies and storylines. Second, the major driving forces that shape and characterise the different scenarios will be identified. The scenario analysis has been provided for the research project Risk Habitat Megacity (HRM) that aims at developing strategies for sustainable development in megacities and urban agglomerations. The analysis of international scenario surveys is an essential component within RHM. The scenario analysis will be the basis and source for the development of own RHM-framework scenarios and for defining specific driving forces of change.

Assessing scenarios on the future of work

In this paper will be discussed different types of scenarios and the aims for using scenarios. Normaly they are being used by organisations due to the need to anticipate processes, to support policy-making and to understand the complexities of relations. Such organisations can be private companies, R&D organisations and networks of organisations, or even by some public administration institutions. Some cases will be discussed as the methods for ongoing scenario-building process (Shell Internacional). Scenarios should anticipate possible relations among social actors as in the Triple Helix Model, and is possible to develop strategic intelligence in the innovation process that would enable the construction of scenarios. Such processes can be assessed. The focus will be made in relation to the steps chosen for the WORKS scenarios. In this case is there a model of work changes that can be used for foresight? Differences according to sectors were found, as well on other dimensions. Problems of assessment are analysed with specific application to the scenario construction methods.

Integrating the theme approach with aspectual scenarios

Dissertação de Mestrado em Engenharia Informática

Robustness of timber structures in seismic areas

Some of the properties sought in seismic design of buildings are also considered fundamental to guarantee structural robustness. Moreover, some key concepts are common to both seismic and robustness design. In fact, both analyses consider events with a very small probability of occurrence, and consequently, a significant level of damage is admissible. As very rare events,in both cases, the actions are extremely hard to quantify. The acceptance of limited damage requires a system based analysis of structures, rather than an element by element methodology, as employed for other load cases. As for robustness analysis, in seismic design the main objective is to guarantee that the structure survives an earthquake, without extensive damage. In the case of seismic design, this is achieved by guaranteeing the dissipation of energy through plastic hinges distributed in the structure. For this to be possible, some key properties must be assured, in particular ductility and redundancy. The same properties could be fundamental in robustness design, as a structure can only sustain significant damage if capable of distributing stresses to parts of the structure unaffected by the triggering event. Timber is often used for primary load‐bearing elements in single storey long‐span structures for public buildings and arenas, where severe consequences can be expected if one or more of the primary load bearing elements fail. The structural system used for these structures consists of main frames, secondary elements and bracing elements. The main frame, composed by columns and beams, can be seen as key elements in the system and should be designed with high safety against failure and under strict quality control. The main frames may sometimes be designed with moment resisting joints between columns and beams. Scenarios, where one or more of these key elements, fail should be considered at least for high consequence buildings. Two alternative strategies may be applied: isolation of collapsing sections and, provision of alternate load paths [1]. The first one is relatively straightforward to provide by deliberately designing the secondary structural system less strong and stiff. Alternatively, the secondary structural system and the bracing system can be design so that loss of capacity in the main frame does not lead to the collapse. A case study has been selected aiming to assess the consequences of these two different strategies, in particular, under seismic loads.

A framework for robustness assessment in the context of corroded RC structures

Structural robustness is an emergent concept related to the structural response to damage. At the present time, robustness is not well defined and much controversy still remains around this subject. Even if robustness has seen growing interest as a consequence of catastrophic consequences due to extreme events, the fact is that the concept can also be very useful when considered on more probable exposure scenarios such as deterioration, among others. This paper intends to be a contribution to the definition of structural robustness, especially in the analysis of reinforced concrete structures subjected to corrosion. To achieve this, first of all, several proposed robustness definitions and indicators and misunderstood concepts will be analyzed and compared. From this point and regarding a concept that could be applied to most type of structures and dam-age scenarios, a robustness definition is proposed. To illustrate the proposed concept, an example of corroded reinforced concrete structures will be analyzed using nonlinear analysis numerical methods based on a contin-uum strong discontinuities approach and isotropic damage models for concrete. Finally the robustness of the presented example will be assessed.

The International Multilateral System: Imperatives of Change, Potential Scenarios and Suggestions for the Future

Thesis presented to satisfy the necessary requirements for obtaining a PhD degree in International Relation with specialization in Globalization and the Environment,

Empirical models for quantification of machining damage in composite materials

Dissertação para obtenção do Grau de Doutor em Engenharia Mecânica

Impacts of climate change scenarios on terrestrial productivity and biomass for energy in the Iberian Peninsula: assessment through the JSBACH model

Dissertação para obtenção do Grau de Mestre em Engenharia do Ambiente, Perfil de Gestão e Sistemas Ambientais

Credit risk stress testing: The Portuguese environment, macroeconomic scenarios and the estimation of losses for corporate sectors

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

Image processing methodology for assessment of drilling induced damage in CFRP

Dissertação para obtenção do Grau de Mestre em Engenharia Mecânica

DNA damage induced by acrylamide: roe of genetic polymorphisms in DNA damage levels

RESUMO:Em 1994 a acrilamida (AA) foi classificada pela IARC como um provável cancerígeno para o homem. Para além da utilização de AA em numerosas aplicações industriais, a AA está também presente numa grande variedade de alimentos ricos em amido e processados a temperaturas elevadas. Esta exposição através da ingestão de produtos alimentares despoletou elevadas preocupações ao nível do risco para a saúde pública e poderá implicar um risco adicional para o aparecimento de cancro. A glicidamida (GA), o metabolito epóxido formado a partir da oxidação da AA provavelmente através do citocromo P450 2E1, é considerada por vários estudos, o principal responsável pela carcinogenicidade da AA. Actualmente existe uma escassez de resultados relativamente aos mecanismos de genotoxicidade da AA e GA em células de mamífero. Por este motivo, o objectivo deste estudo centra-se na avaliação das consequências genéticas da exposição à AA e GA, recorrendo-se para tal ao uso de células de mamífero como modelo. Tendo como base este objectivo avaliou-se a citotoxicidade da AA e GA, através do ensaio do MTT, e realizaram-se dois testes citogenéticos, o teste das aberrações cromossómicas (CAs) e o teste da troca de cromátides irmãs (SCEs), de modo a avaliar as lesões de DNA induzidas por estes compostos em células de hamster Chinês V79. Os resultados globalmente mostraram que a GA é mais citotóxica e clastogénica do que a AA. No âmbito deste trabalho, foi também efectuada a quantificação de aductos específicos de DNA, nomeadamente N7-(2-carbamoil-2-hidroxietil)guanina (N7-GA-Gua) e N3-(2-carbamoil-2-hidroxietil)adenina (N3-GA-Ade). Os resultados obtidos permitem afirmar que os níveis de N7-GA-Gua e a concentração de GA apresentam uma relação linear dose-resposta. Foi também identificada uma óptima correlação entre os níveis de N7-GA-Gua e a frequência de troca de cromátides irmãs. Adicionalmente, e de forma a compreender os mecanismos de toxicidade da AA, estudaram-se os mecanismos dependentes da modulação do glutationo reduzido (GSH), nomeadamente da butionina sulfoximina (BSO), um inibidor da síntese de GSH, do GSH-monoetil estér (GSH-EE), um composto permeável nas células e que é intra-celularmente hidrolisado a GSH e ainda do GSH adicionado exogenamente ao meio de cultura, em células V79. Os resultados obtidos reforçaram o papel da modulação do GSH nos efeitos de citotoxicidade e clastogenicidade da AA. Para além dos estudos efetuados com células V79, procedeu-se também à determinação da frequência de SCEs, à quantificação de aductos específicos de DNA, bem como ao ensaio do cometa alcalino em amostras de dadores saudáveis expostos à AA e GA. Tanto os resultados obtidos através do ensaio das SCE, como pela quantificação de aductos específicos de DNA, ambos efectuados em linfócitos estimulados, originaram resultados comparáveis aos obtidos anteriormente para as células V79, reforçando a ideia de que a GA é bastante mais genotóxica do que a AA. Por outro lado, os resultados obtidos pelo ensaio do cometa para exposição à AA e GA mostraram que apenas esta última aumenta o nível das lesões de DNA. Outro objectivo deste trabalho, foi a identificação de possíveis associações existentes entre as lesões de DNA, quantificadas através do ensaio das SCEs e do cometa, e biomarcadores de susceptibilidade, tendo em conta os polimorfismos genéticos individuais envolvidos na destoxificação e nas vias de reparação do DNA (BER, NER, HRR e NHEJ) em linfócitos expostos à GA. Tal permitiu identificar associações entre os níveis de lesão de DNA determinados através do ensaio das SCEs, e os polimorfismos genéticos estudados, apontando para uma possível associação entre o GSTP1 (Ile105Val) e GSTA2 (Glu210Ala) e a frequência de SCEs. Por outro lado, os resultados obtidos através do ensaio do cometa sugerem uma associação entre as lesões de DNA e polimorfismos da via BER (MUTYH Gln335His e XRCC1 Gln39Arg) e da via NER (XPC Ala499val e Lys939Gln), considerando os genes isoladamente ou combinados. Estes estudos contribuem para um melhor entendimento da genotoxicidade e carcinogenicidade da AA e GA em células de mamífero, bem como da variabilidade da susceptibilidade individual na destoxificação e reparação de lesões de DNA provocadas pela exposição a estes xenobióticos alimentares. ----------- ABSTRACT:Acrylamide (AA) has been classified as a probable human carcinogen by IARC. Besides being used in numerous industrial applications, AA is also present in a variety of starchy cooked foods. This AA exposure scenario raised concerns about risk in human health and suggests that the oral consumption of AA is an additional risk factor for cancer. A considerable number of findings strongly suggest that the reactive metabolite glycidamide (GA), an epoxide generated presumably by cytochrome P450 2E1, plays a central role in AA carcinogenesis. Until now there are a scarcity of results concerning the mechanisms of genotoxicity of AA and GA in mammalian cells. In view of that, the study described in this thesis aims to unveil the genetic consequences of AA and GA exposure using mammalian cells as a model system. With this aim we evaluated the cytotoxicity of AA and GA using the MTT assay and subsequently performed two cytogenetic end-points: chromosomal aberrations (CAs) and sister chromatid exchanges (SCEs), in order to evaluate DNA damage induced by these compounds in V79 Chinese hamster cell line. The results showed that GA was more cytotoxic and clastogenic than AA. Within the scope of this thesis the quantification of specific DNA adducts were also performed, namely N7-(2-carbamoyl-2-hydroxyethyl)guanine (N7-GA-Gua) and N3-(2-carbamoyl-2-hydroxyethyl)adenine (N3-GA-Ade). Interestingly, the GA concentration and the levels of N7-GA-Gua presented a linear dose-response relationship. Further, a very good correlation between the levels of N7-GA-Gua and the extent of SCEs were observed. In order to understand the mechanisms of AA-induced toxicity, the modulation of reduced glutathione (GSH)-dependent mechanisms were studied, namely the evaluation of the effect of buthionine sulfoximine (BSO), an effective inhibitor of GSH synthesis, of GSH-monoethyl ester (GSH-EE), a cell permeable compound that is intracellularly hydrolysed to GSH and also of GSH endogenously added to culture medium,z in V79 cell line. The overall results reinforced the role of GSH in the modulation of the cytotoxic and clastogenic effects induced by AA.Complementary to the studies performed in V79 cells, SCEs, specific DNA-adducts and alkaline comet assay in lymphocytes from healthy donors exposed to AA and GA were also evaluated. Both, the frequency of SCE and the quantification of specific GA DNA adducts, produced comparable results with those obtained in V79 cell line, reinforcing the idea that GA is far more genotoxic than AA. Further, the DNA damaging potential of AA and GA in whole blood leukocytes evaluated by the alkaline comet assay, showed that GA, but not AA, increases DNA damage. Additionally, this study aimed to identify associations between DNA damage and biomarkers of susceptibility, concerning individual genetic polymorphisms involved in detoxification and DNA repair pathways (BER, NER, HRR and NHEJ) on the GA-induced genotoxicity assessed by the SCE assay and by the alkaline comet assay. The extent of DNA damage determined by the levels of SCEs induced by GA seems to be modulated by GSTP1 (Ile105Val) and GSTA2 (Glu210Ala) genotypes. Moreover, the results obtained from the comet assay suggested associations between DNA damage and polymorphisms of BER (MUTYH Gln335His and XRCC1 Gln399Arg) and NER (XPC Ala499Val and Lys939Gln) genes, either alone or in combination. The overall results from this study contribute to a better understanding of the genotoxicity and carcinogenicity of AA and GA in mammalian cells, as well as the knowledge about the variability in individual susceptibility involved in detoxification and repair of DNA damage due to these dietary xenobiotics.

Geospatial assessment of pest-induced forest damage through the use of UAV-bases NIR imaging and Gi-technology

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.

Predisposition assessment modelling

Dissertation submitted for obtaining the degree of Master in Environmental Engineering

Clearing the cloudy crystal balls: Hybrid modelling for energy and climate change mitigation scenarios – A case study for Portugal

Dissertação para obtenção do Grau de Doutor em Ambiente