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Simulação numérica integrada do comportamento de um navio amarrado no Terminal XXI do Porto de Sines
No full textEste trabalho apresenta a aplicação da ferramenta numérica SWAMS para caracterizar o comportamento de um navio amarrado na bacia do Terminal de Contentores do Porto de Sines. São analisados os movimentos do navio, as forças nas amarras e nas defensas. Analisa-se ainda a influência do vento e da introdução de pré tensionamento nas amarras assim como a resposta do sistema quando sujeito a ondas longas. Os resultados permitem avaliar qual destes fatores tem maior influência sobre os movimentos do navio e a sua segurança.81-87ppDHA/NP
Application of the numerical model SWAN in locations with vegetation in the Tiete-Paraná waterway—lake of Ilha Solteira’s Dam—Brazil
No full textThis paper describes the application of SWAN-VEG to the lake of Ilha Solteiras’s dam—São Paulo, Brazil that is part of the Tietê-Paraná waterway, in order to analyze the influence of vegetation on the reduction of energy of the waves near the lake margins. First the model is applied considering a constant water depth in the entire dam reservoir and a small area of vegetation is implemented at the end of the dam. Several values of velocity and wind directions as well as different vegetation characteristics are tested. Then, the real bathymetry of the lake is considered as well as vegetation in certain margins of the lake. Several wind conditions are tested and compared with the situation with and without vegetation.1371-1378ppDHA/NP
“Libertar” a habitação das instalações
No full textAqui se quer definir por “instalações” se refere a todo um conjunto de "aparatos" técnicos, associados a redes técnicas diversas com especial enfoque nas águas, esgotos, electricidade e redes de telecomunicações por cabo, que são fundamentais para o habitar doméstico e cujas ligações ou “pontos” de serviço estão disseminados pelos vários espaços da habitação, proporcionando padrões de uso das respetivas instalações que devem ser eficazes no sentido das respetivas utilidades.1 fig4 pInfohabitar, Ano X, n.º 496DED/NUTRevista Infohabita
Effects of thermal cycles on the mechanical response of pultruded GFRP profiles used in civil engineering applications
No full textThis paper presents a literature review and results of an experimental study about the effects of thermal cycles on the physical and mechanical properties of pultruded glass fibre reinforced polymer (GFRP) profiles used in civil engineering structural applications. The GFRP profiles used in this study present similar fibre architecture, differing only in their matrix nature: unsaturated polyester and vinylester. Small-scale coupons obtained from both types of GFRP profiles were exposed to a Mediterranean range of thermal variations (-5 °C to 40 °C) for up to 190 cycles in a dry condition. The effects of such exposure on the physical and mechanical response of the GFRP materials were assessed and compared using the following experimental techniques: (a) dynamic mechanical analyses (DMA) to assess the viscoelastic behaviour; (b) tensile, flexural and interlaminar shear tests, to evaluate the mechanical properties; and (c) scanning electron microscopy (SEM), to monitor the potential changes in the microstructure due to the degradation (if any) caused by the thermal cycles, as well as the possible changes into the main mechanisms of fracture. After exposure to thermal cycles, the viscoelastic behaviour of the GFRP profiles presented only slight changes, indicating no significant degradation, neither in the matrix structure nor at the fibre-matrix interphase. In terms of mechanical properties, both types of GFRP materials suffered slight changes regarding tensile and interlaminar shear properties. Flexural properties were more affected, particularly the flexural modulus, especially in the first cycles, as degradation tended to stabilize for increasing cycles. The GFRP profile made of vinylester resin presented better overall performance than the one made of polyester, especially regarding the tensile properties. SEM observations of the surfaces of fracture of mechanically tested pultruded specimens showed two main mechanisms of crack propagation: cohesive rupture (matrix cracking), where the crack propagates inside the matrix, and adhesive rupture (fibre-matrix debonding), where the crack propagates at the interface fibre-matrix. Degradation of the polyester matrix caused by the thermal cycles is evidenced by extensive matrix microcracking and increased fibre-matrix debonding. The vinylester matrix resists better to such degradation as fibre-matrix debonding occurs in less extent, and matrix microcracking is scarcely present.14312116DM/NMOComposite Structure
Estação meteorológica do LNEC - Compilação de dados – ano 2013 Edifício Principal – Terraço da ala Nascente
No full textEste registo pertence ao Repositório Científico do LNECNo presente relatório apresentam-se os dados meteorológicos do ano de 2013, recolhidos na estação
meteorológica existente no Núcleo de Materiais Orgânicos do Departamento de Materiais do LNEC, em Lisboa.Estudo efetuado no âmbito do Plano de Investigação e Inovação do LNEC para 2013-2020 / NÃO CONFIDENCIALDM/NM
Development of an oil spill hazard scenarios database for risk assessment
No full textThe occurrence of oil spills in coastal regions may have catastrophic consequences on the environment and severe
socio-economic impacts. This work presents a new methodology to evaluate the risk associated with oil spills in coastal
zones and estuaries, and illustrates its application in a coastal lagoon (Ria de Aveiro, Portugal). A ranked list of the
hydrodynamic scenarios under which oil spills are most likely generated through the analysis of 33 years of wave and
wind data, retrieved from the ERA-INTERIM project database, and from the analysis of oil spills that occurred in the
Atlantic Iberian shelf. Considering six spill locations and a single oil type spill inside the Aveiro harbor, the database
resulted in approximately 3500 simulations. Hydrodynamic simulations were made with the MORSYS2D modeling
system, a soft coupling of the hydrodynamic model ELCIRC and the wave model SWAN. The high-accuracy,
unstructured grid, oil fate model VOILS was used in 2D mode to simulate the transport and the oil weathering processes
at the surface and in the intertidal areas. The hazard assessment analysis included the determination of the trajectory of
the plumes, the shoreline retention areas affected by the oil and their oil exposure time. Time evolution of the oil
properties, such as the oil evaporation rate and emulsification processes of the mixture, are provided to support clean-up
operations, as well as robustness controls such as oil mass balance.f10t3p6DHA/GT
Projeto de investigação programada “Alterações climáticas e águas subterrâneas” - Relatório final de apresentação de resultados
No full textEste registo pertence ao Repositório Científico do LNECNo presente relatório apresentam-se os objetivos, as atividades desenvolvidas, os resultados obtidos
do projeto supracitado e a bibliografia produzida, assim como as alterações ao programa inicialmente
estabelecido, de modo a superar limitações que foram ocorrendo ao longo da investigação. Os
resultados apresentam-se associados aos projetos que lhes deram origem e que concorreram para o
presente Projecto de Investigação Programada.422571ppNÃO CONFIDENCIAL2391 - Arquivado na SE do DHADHA/NR
Modelação numérica da circulação e do transporte na Ria Formosa
No full textEste registo pertence ao Repositório Científico do LNECA Ria Formosa (sul de Portugal) é uma laguna muito produtiva, de elevada importância ecológica e
económica. Assim, perceber os processos que afetam a produtividade deste ecossistema é
fundamental para a sua gestão sustentável. O projeto COALA visa estudar a dinâmica de trocas de
nutrientes, clorofila e material particulado entre a Ria Formosa e o oceano adjacente, assim como a
influência dos principais forçamentos (e.g. maré) nesta dinâmica, utilizando uma abordagem
multidisciplinar que combina modelação numérica e campanhas de campo. O modelo hidrodinâmico
SELFE foi aplicado na Ria Formosa, representando adequadamente os principais padrões de
circulação. Este modelo foi combinado com um modelo de transporte lagrangeano para estudar a
influência dos forçamentos ambientais na dinâmica de trocas lagoa – oceano. Foram simulados
diversos cenários de vento, de batimetria e de descarga de efluentes de estações de tratamento de
águas residuais (ETAR) locais. Os resultados sugerem uma influência significativa do vento e da
batimetria na quantidade de partículas exportadas para a zona exterior a escalas temporais curtas. A
análise do transporte de potenciais poluentes (e.g. nutrientes) das estações de tratamento de águas
residuais pode contribuir para suportar a gestão da Ria Formosa.875172ppCOALA: Dinâmica dos nutrientes e da matéria particulada –
trocas entre uma lagoa costeira e o oceano adjacente através
de um sistema de múltiplas barras: o caso da Ria Formosa,
sul de Portugal
Fundação para a Ciência e a Tecnologia / NÃO CONFIDENCIAL2390 - Arquivado na Se do DHADHA/NE
Implementation of an early warning system in urban drainage infrastructures for direct discharges and flood risk management
No full textCombined sewer systems are often unable to respond adequately to rising water
volumes draining from urban areas during rainfall events, resulting in frequent
direct discharges into receiving waters and floods, with severe environmental
and economic impacts. Despite stricter legislation on pollution control and flood
risk assessment, there are still some challenges regarding the development of
early warning systems based on water quality issues and fully integrated models.
An innovative, real-time urban warning system for flooding and pollution events
was built for the Alcântara basin (the largest in Lisbon), to provide timely
information to wastewater management entities and to civil protection services.
The platform provides real-time access to monitoring data and, based on 48-hour
precipitation forecasts, predicts the performance of the system through the
integrated use of mathematical models for both drainage network and estuary.
Predictions are automatically compared and validated with on-line data. This
paper presents the overall design of the system and main results obtained thus
far. The analysis of the system shows the ability of the integrated models to
represent the main spatial and temporal patterns observed, effectively predicting
the system response to precipitation events and estimating volumes discharged
into the water bodies and their average pollution loads. Furthermore, the overall results strongly indicate UV-Vis spectra to be reliable for TSS and COD
estimation in sewer systems.f7p10DHA/GT
HIDRALERTA Project – A flood forecast and alert system in coastal and port areas
No full textThis paper describes the recent advances on the research project HIDRALERTA - "Flood Forecast and Early Warning System in Coastal and Port Areas", whose main objective is developing a system for forecasting, warning and assessment of risks associated with wave overtopping and flooding in coastal and port areas, supported by measurements/predictions of waves and water levels in these areas. The case study here presented is the port and bay of Praia da Vitória, at the Terceira Island, Azores. Methodologies and accomplishments of the HIDRALERTA project achieved so far, with the focus on its more relevant results, are herein described.8pDHA/NP