Papers

The cryptic habits of subterranean termites impair studies of colony delimitation and the organization of foraging. Whereas feeding sites can be identified and the movements of foragers between them can be assessed using traditional mark-release techniques, the assignment of the termites found at feeding sites to their parent colonies remains problematical. Thus the extent and overlap of individual colony foraging territories are unknown. We used microsatellite markers to delineate colonies of R. grassei and compared the results with data from a mark-release-recapture study (Nobre et al., 2007)carried out in the same population and over the same period of time. The majority of colonies exhibited only a single-feeding site, but presented, even at a local scale, a high degree of variability in colony structure and no evidence of inbreeding. F-statistics for some colonies were consistent with pleometrosis. The population as a whole contained individual colonies that were separately identified as Mendelian, mixed family or pleometrotic families. Furthermore, microsatellite data suggest that what was represented by the MRR technique as a single foraging group could be drawn from more than one colony. Colony delineation is discussed as a tool for understanding overall population structure and termite feeding strategies.

Four different PVC formulations, designed for outdoor applications, in the form of calen dered films, were submitted to artificial accelerated ageing under different radiation sources, with and without water spray, and also to natural exposure. The influence of the different photo-oxidation conditions was evaluated by means of surface analysis using X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy. The photo-oxidation of PVC is well monitored by FTIR measurements by following the formation of oxidation products of the carbonyl type, which are due to radical attack on the double bonds in the molecular structure of PVC, and enhanced by radiation and temperature. Results show that relative rates of PVC degradation reactions are different under different photo-oxidative conditions. XPS results show that, in technical PVC formulations, the fraction of chloride ions trapped in the inorganic filler is a better parameter to measure the PVC degradation (measured by the yellowing index variation) than the total remaining (or lost) chlorine in the surface. When the ageing method includes water jets, the top superficial layers made from the inorganic filler and the organic products from the PVC degradation are removed and leave behind a much more homogeneous layer which is more resistant to ageing than the ‘‘as processed’’ one that contains defects introduced by the calendering process. XPS also makes clear that zinc–calcium additive is a better thermal stabilizer than dibutyltin-maleate, and the presence of tinuvin P retards the PVC degradation. The best simulation of the natural weathering of such PVC materials under laboratory conditions needs to consider, besides the light, the intervention of water jets and/or humidity as well as the existence of light and dark periods.

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As esculturas de exterior em liga de cobre, sem a aplicação de medidas de protecção, podem mostrar aceleração da degradação devido à corrosão, agravada pelo aumento da poluição atmosférica associado ao desenvolvimento industrial e social do último século. Da corrosão resulta a alteração cromática da superfície das estátuas, com a formação de patinas de cor verde e preta, cujas características definem níveis de risco de degradação e, consequentemente, o tipo de intervenção a que a escultura deverá ser submetida para a sua conservação. Neste artigo abordam-se os processos de corrosão mais comuns em estátuas de ligas de cobre expostas no exterior e descreve-se a formação, composição e estrutura das patinas resultantes dessa corrosão. Referem-se ainda alguns aspectos sobre a conservação deste tipo de obras de arte

Portugal is one of the European countries in which built heritage is a testimony of its history. In this context, the legacy of the decorative glazed tile coatings of facades must be preserved and restored. This research is dedicated to the conservation of such facades in the city of Ovar, considered an example due to its rich heritage in glazed tiles, a high percentage of which requires a deep intervention. Therefore, this work is focused on the study of lime renders, serving as a support for this type of tile facades. For this, samples were collected from several buildings in the city, targeting their mechanical and physical study with the aim of producing compatible mortars to be used for application of detached tiles in these buildings and generally for the repair of the facades with glazed tile coatings. For this purpose, four mixtures of lime mortars with different volumetric ratios were composed. The aggregates used were: ordinary river sand and a local gravel. In three of the mixtures metakaolin, was added, with the intention of acting as an artificial pozzolan and thus improving the performance of these mortars. The use of a pozzolanic addition promotes hardening of lime mortars in cases when the ingression of carbon dioxide is low as is the case of mortars placed below glazed tile coatings. These mortars were also tested in the laboratory taking into account their physical and mechanical characteristics. The mechanical characteristics determined were: modulus of elasticity (E) by two different methods, compressive strength and flexural strength. In turn, the physical characteristics determined were: water vapour permeability and water absorption by total immersion and capillary action. The best mechanical behaviour (compressive and flexural) was observed in the mortar with pozzolanic additions. Similarly, the value of the modulus of elasticity was better in mortars with pozzolanic additions. The performance of these mortars was also adequate in terms of water behaviour. The mortars revealed suitable characteristics for application in building conservation situations concerning coating with glazed tiles.

Digital preservation aims at maintaining digital objects and data accessible over long periods of time. The emerging context of e- Science imposes new scenarios and new requirements for digital preser- vation. This paper presents the main issues, current solutions and promi- nent projects for digital preservation and e-Science data management. Fi- nally, it presents the problem to be addressed, the solutions to explore, the proposed methodology and expected contributions of the associated PhD work.

Digital preservation aims at maintaining digital objects and data accessible over long periods of time. We propose the use of dedicated or surplus storage resources of data grids to build frameworks of digital preservation. In this paper we focus on the problem of digital preservation in two scenarios: a national digital library and a repository of scientific information for dam safety. We detail the scenario of dam safety data and provide an analysis of an existing data grid solution that can be used for this purpose.

Apresenta-se uma panorâmica geral sobre os principais problemas relacionados com a fisiografia costeira e as principais técnicas de protecção da orla costeira. Referem-se os processos físicos responsáveis pela dinâmica sedimentar, e os principais problemas a ela associados que afectam praias e embocaduras de estuários e lagunas. As soluções mais comuns para este tipo de problemas são depois revistas de forma crítica. Finalmente, três casos de estudo são utilizados para exemplificar problemas e soluções, e, simultaneamente, ilustrar abordagens seguidas em estudos de engenharia: uma praia encaixada em erosão (praia de Hac-Sá, República Popular da China), um sistema no Rio de Janeiro, Brasil, composto por uma praia arqueada (praias de Leblon, Ipanema e Arpoador), um canal e uma laguna com problemas simultâneos de erosão e assoreamento e uma embocadura lagunar com problemas de assoreamento e de estabilidade (Lagoa de Óbidos, Portugal).

Performance assessment (PA) of urban infrastructure services, mainly in the case of water systems, is becoming a major issue worldwide. Therefore, in the last decade, the need for a clear definition of management objectives of water services and the subsequent need to monitor goals achievement have led to the development of some initiatives to tackle the evaluation of the efficiency of those services, their main aim being the definitin of systems of performance indicators. However, these PA systems are strongly oriented by a management/economic perspective and technical aspects have often been ignored. In addition, none of them has specifically addressed the drinking water treatment. This paper presents a proposal for a PI system that applies to drinking water treatment facilities as a part of a standardised methodology for performance assessment. In total, ca.80 PI have been define and classified according to seven evaluation domains, namely: treated water quality; plant reliability; use of natural resources and raw materials; by-products management; safety; human resources; and, economical and financial resources.

Em muitas utilizações, especialmente em ambientes húmidos ou expostos à chuva, o risco de degradação da madeira depende em grande medida das disposições construtivas adoptadas, no que se refere à pormenorização e ao cuidado na realização das ligações. A absorção e retenção de água pela madeira podem ocasionar o seu inchamento e ataque por insectos como as térmitas subterrâneas, ou a instalação e o desenvolvimento de fungos causadores de manchas ou de podridão. A variação das condições ambientais provoca ainda empenos e fendas. Compreende-se assim a importância da pormenorização para o desempenho e a durabilidade das estruturas de madeira, no sentido de limitar o acesso da água à madeira, promover a sua eliminação rápida e/ou minimizar as suas consequências. Também a escolha de materiais e a execução podem comprometer de forma drástica a qualidade e a durabilidade das estruturas, referindo-se adiante alguns aspectos relacionados com as ligações.