299 research outputs found

    Indicadores para avaliação dos impactos ambientais e sociais das nano-cápsulas e nanopartículas na agricultura.

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    Resumo: A Nanotecnologia oferece a perspectiva de grandes avanços que permitirão melhorar a qualidade de vida e preservar o meio ambiente e os nano-produtos agrícolas ganham espaço com as descobertas de novas aplicações, muitas das quais já disponíveis no mercado. Este projeto visa desenvolver indicadores para avaliação dos impactos ambientais e sociais das nano-cápsulas e nano-partículas utilizadas na agricultura. Estes serão futuramente validados através de consultas a especialistas de áreas correlatas à Nanotecnologia na Agricultura e utilizados no software Impactos NanoAgri

    Emprego da técnica Delphi para validação de indicadores de impacto de nanotecnologias agrícolas.

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    Para estudar os impactos das nanotecnologias agrícolas é essencial avaliar quais fatores definem o sistema estudado com base na literatura especializada, embasando estes indicadores com dados científicos relevantes e de consenso na comunidade científica. Após o levantamento, os indicadores devem passar por um processo de validação para que tenha relevância técnica e credibilidade científica. Existem várias modalidades de validação, a escolhida pela equipe consistiu em submeter os indicadores em formato de questionários a um painel de convidados, empregando a Técnica Delphi. Através da análise das respostas foi possível elaborar um perfil dos especialistas envolvidos com pesquisas na área de Nanotecnologia no Brasil, além de informações que podem contribuir para melhorar a eficiência de futuras consultas

    Wave climate of the Adriatic Sea: a future scenario simulation

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    Abstract. We present a study on expected wind wave severity changes in the Adriatic Sea for the period 2070–2099 and their impact on extremes. To do so, the phase-averaged spectral wave model SWAN is forced using wind fields computed by the high-resolution regional climate model COSMO-CLM, the climate version of the COSMO meteorological model downscaled from a global climate model running under the IPCC-A1B emission scenario. Namely, the adopted wind fields are given with a horizontal resolution of 14 km and 40 vertical levels, and they are prepared by the Italian Aerospace Research Centre (CIRA). Firstly, in order to infer the wave model accuracy in predicting seasonal variability and extreme events, SWAN results are validated against a control simulation, which covers the period 1965–1994. In particular, numerical predictions of the significant wave height Hs are compared against available in-situ data. Further, a statistical analysis is carried out to estimate changes on wave storms and extremes during the simulated periods (control and future scenario simulations). In particular, the generalized Pareto distribution is used to predict changes of storm peak Hs for frequent and rare storms in the Adriatic Sea. Finally, Borgman's theory is applied to estimate the spatial pattern of the expected maximum wave height Hmax during a storm, both for the present climate and that of the future scenario. Results show a future wave climate in the Adriatic Sea milder than the present climate, even though increases of wave severity can occur locally

    Wave extreme characterization using self-organizing maps

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    The self-organizing map (SOM) technique is considered and extended to assess the extremes of a multivariate sea wave climate at a site. The main purpose is to obtain a more complete representation of the sea states, including the most severe states that otherwise would be missed by a SOM. Indeed, it is commonly recognized, and herein confirmed, that a SOM is a good regressor of a sample if the frequency of events is high (e.g., for low/moderate sea states), while a SOM fails if the frequency is low (e.g., for the most severe sea states). Therefore, we have considered a trivariate wave climate (composed by significant wave height, mean wave period and mean wave direction) collected continuously at the Acqua Alta oceanographic tower (northern Adriatic Sea, Italy) during the period 1979–2008. Three different strategies derived by SOM have been tested in order to capture the most extreme events. The first contemplates a pre-processing of the input data set aimed at reducing redundancies; the second, based on the post-processing of SOM outputs, consists in a two-step SOM where the first step is applied to the original data set, and the second step is applied on the events exceeding a given threshold. A complete graphical representation of the outcomes of a two-step SOM is proposed. Results suggest that the post-processing strategy is more effective than the pre-processing one in order to represent the wave climate extremes. An application of the proposed two-step approach is also provided, showing that a proper representation of the extreme wave climate leads to enhanced quantification of, for instance, the alongshore component of the wave energy flux in shallow water. Finally, the third strategy focuses on the peaks of the storms

    Stokes drift

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    During its periodic motion, a particle floating at the free surface of a water wave experiences a net drift velocity in the direction of wave propagation, known as the Stokes drift (Stokes 1847 Trans. Camb. Philos. Soc.8, 441-455). More generally, the Stokes drift velocity is the difference between the average Lagrangian flow velocity of a fluid parcel and the average Eulerian flow velocity of the fluid. This paper reviews progress in fundamental and applied research on the induced mean flow associated with surface gravity waves since the first description of the Stokes drift, now 170 years ago. After briefly reviewing the fundamental physical processes, most of which have been established for decades, the review addresses progress in laboratory and field observations of the Stokes drift. Despite more than a century of experimental studies, laboratory studies of the mean circulation set up by waves in a laboratory flume remain somewhat contentious. In the field, rapid advances are expected due to increasingly small and cheap sensors and transmitters, making widespread use of small surface-following drifters possible. We also discuss remote sensing of the Stokes drift from high-frequency radar. Finally, the paper discusses the three main areas of application of the Stokes drift: in the coastal zone, in Eulerian models of the upper ocean layer and in the modelling of tracer transport, such as oil and plastic pollution. Future climate models will probably involve full coupling of ocean and atmosphere systems, in which the wave model provides consistent forcing on the ocean surface boundary layer. Together with the advent of new space-borne instruments that can measure surface Stokes drift, such models hold the promise of quantifying the impact of wave effects on the global atmosphere-ocean system and hopefully contribute to improved climate projections.This article is part of the theme issue 'Nonlinear water waves'

    Wave climate of the Adriatic Sea: a future scenario simulation

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    We present a study on expected wind wave severity changes in the Adriatic Sea for the period 2070–2099 and their impact on extremes. To do so, the phase-averaged spectral wave model SWAN is forced using wind fields computed by the high-resolution regional climate model COSMO-CLM, the climate version of the COSMO meteorological model downscaled from a global climate model running under the IPCC-A1B emission scenario. Namely, the adopted wind fields are given with a horizontal resolution of 14 km and 40 vertical levels, and they are prepared by the Italian Aerospace Research Centre (CIRA). Firstly, in order to infer the wave model accuracy in predicting seasonal variability and extreme events, SWAN results are validated against a control simulation, which covers the period 1965–1994. In particular, numerical predictions of the significant wave height <i>H</i><sub>s</sub> are compared against available in-situ data. Further, a statistical analysis is carried out to estimate changes on wave storms and extremes during the simulated periods (control and future scenario simulations). In particular, the generalized Pareto distribution is used to predict changes of storm peak <i>H</i><sub>s</sub> for frequent and rare storms in the Adriatic Sea. Finally, Borgman's theory is applied to estimate the spatial pattern of the expected maximum wave height <i>H</i><sub>max</sub> during a storm, both for the present climate and that of the future scenario. Results show a future wave climate in the Adriatic Sea milder than the present climate, even though increases of wave severity can occur locally

    Geodetic Observations at the Eolian Islands (Southern Italy)

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    In order to investigate the dynamic processes actually in progress in the Aeolian Islands a volcanic area in Southern Italy, high precision geodetic observations are employed. the knowledge of the kinematic field (vertical and horizontal displacements) and of the time-space gravity variations is an important constrain for any model describing the geodynamic processes involving the investigated area. Gravimetric (absolute, relative and gradiometric), photogrammetric, altimetric and GPS surveys are periodically carried out on networks spanning over the whole aeolian archipelagus. Recently a GPS network has been designed and surveyed to obtain a more complete knowledge of the kinematic field taking place in the area. This will improve the understanding of the tectonic processes acting in the area. The result of the interdisplinary approach are presented and discussed.Published33-501.3. TTC - Sorveglianza geodetica delle aree vulcaniche attivereserve

    Relative sea-level rise and potential submersion risk for 2100 on 16 coastal plains of the mediterranean sea

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    The coasts of the Mediterranean Sea are dynamic habitats in which human activities have been conducted for centuries and which feature micro-tidal environments with about 0.40 m of range. For this reason, human settlements are still concentrated along a narrow coastline strip, where any change in the sea level and coastal dynamics may impact anthropic activities. In the frame of the RITMARE and the Copernicus Projects, we analyzed light detection and ranging (LiDAR) and Copernicus Earth Observation data to provide estimates of potential marine submersion for 2100 for 16 small-sized coastal plains located in the Italian peninsula and four Mediterranean countries (France, Spain, Tunisia, Cyprus) all characterized by different geological, tectonic and morphological features. The objective of this multidisciplinary study is to provide the first maps of sea-level rise scenarios for 2100 for the IPCC RCP 8.5 and Rahmstorf (2007) projections for the above affected coastal zones, which are the locations of touristic resorts, railways, airports and heritage sites. On the basis of our model (eustatic projection for 2100, glaciohydrostasy values and tectonic vertical movement), we provide 16 high-definition submersion maps. We estimated a potential loss of land for the above areas of between about 148 km2 (IPCC-RCP8.5 scenario) and 192 km2 (Rahmstorf scenario), along a coastline length of about 400 km
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