137 research outputs found

    Ultimate loads and response analysis of a monopile supported offshore wind turbine using fully coupled simulation

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    This PhD research is funded by Lloyd’s Register Group Services Ltd., Aberdeen. Sriramula’s work within the Lloyd’s Register Foundation Centre for Safety and Reliability Engineering at the University of Aberdeen is supported by Lloyd’s Register Foundation. The Foundation helps to protect life and property by supporting engineering-related education, public engagement and the application of research. We would also like to acknowledge the constant assistance provided by Jason Jonkman on using FAST.Peer reviewedPostprin

    Synthesizing and standardizing criteria for the evaluation of sustainability indicators in the water sector

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    This is a pre-print of an article published in Environment, Development and Sustainability. The final authenticated version is available online at: https://doi.org/10.1007/s10668-019-00508-zIndicators are one of the tools available in planning and management projects that aid in the decision-making process and the monitoring of those decisions on the path to sustainable use and management of water and natural resources. However, the quality and trustworthiness of the indicators depend on the constant improvement in the means to assess and design criteria sets. The identification of criteria to evaluate indicators and its subsequence selection are not an ordinary task. The research identified a proliferation of unconsolidated criteria in use in the sustainability and water resource management domains. In response, a process of synthesis and consolidation was undertaken in order to reduce the level of redundancies and to identify possible candidates for “core criteria” that are identified as being a relevant part of most evaluation frameworks. A representative collection of sources from the specialized literature was screened for evaluation criteria. Altogether, 74 sources were assessed, comprising 346 mentions of criteria applied for indicator assessment. A detailed synthesis was performed to organize the criteria and identify possible redundancies. The analysis allowed a reduction from the 346 initial criteria to 60 unique criteria. The study offers a standard title and description for each criterion, contributing to improve clarity and avoid ambiguity. The criteria were also ranked to identify which criteria were in more systemic use. Of the 60 criteria found, the 12 most cited were identified as possible core criteria for framework development. Also, in order to facilitate the design of indicator sets, all 60 criteria were divided into two approaches (scientific/top-down or end-use/bottom-up). This study identified significant redundancies and a lack of standardization in the use of criteria, and it also ranked criteria to facilitate multi-method framework development. Thus, it is essential that indicator designers not only consider criteria that have some level of standardization to be able to compare and communicate with other agencies and communities but also consider how to utilize core criteria in the design of indicator sets.Peer ReviewedPostprint (author's final draft

    Assesing heavy metals in the marine bivalve Pinna nobilis in the Balearic Islands (western Mediterranean)

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    Heavy metals (Cd, Cu, Hg, Pb and Zn) concentration were determined in the marine bivalve Pinna nobilis along the Balearic Islands, comparing a protected area with two sites with strong anthropogenic influence. Analyses of Cabrera and Mallorca indicated that heavy metal concentration were generally higher in the most of samples, specially in Santa Maria bay (Cabrera, MPA), and Magaluf (Mallorca, with strong anthropogenic influence). Pinna nobilis appears to efficiently bioaccumulate heavy metals exhibiting large differences in a range of anthropic scenarios. The results on P. nobilis metal accumulation show that the concentrations decrease according to order: Zn > Cu >Pb> Cd > H

    Alto contenido de metales en el molusco Pinna nobilis en el Archipiélago Balear (Mediterráneo occidental) y una revisión de las concentraciones en bivalvos marinos (Pinnidae)

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    Summary: Concentrations of metals (Cd, Cu, Hg, Pb and Zn) in the marine bivalve Pinna nobilis at several coastal locations of Majorca and the Cabrera Islands (Mediterranean Sea) were investigated. The elevated concentrations of metals found in the soft tissues of P. nobilis indicate high bioaccumulation factors. All concentrations and the calculated metal pollution index showed significant differences between sites, with particularly high concentrations in the Cabrera Archipelago, a marine protected area (MPA). The datasets were evaluated with the limited information published in the literature for Pinnidae species worldwide. In benthic P. nobilis, concentrations of Cd, Cu and Zn are more than 30 times higher and Hg and Pb concentrations are 4 and 7 times higher, respectively, than concentrations in other bivalve species, such as Mytilus galloprovincialis (Mytilidae). These observations from species inhabiting nearby ecological habitats of the coastal environment (Pinnidae vs. Mytilidae) are also discussed in the context of current marine monitoring strategies and assessmentsResumen: Se investigaron las concentraciones de metales (Cd, Cu, Hg, Pb y Zn) en el bivalvo marino Pinna nobilis en diferentes localidades costeras de las Islas de Mallorca y Cabrera (Mar Mediterráneo). Las elevadas concentraciones de metales que se encontraron en los tejidos blandos de P. nobilis revelaron una elevada bioacumulación. Las concentraciones de metales estudiadas, así como el índice de contaminación por metales (ICM) mostraron diferencias significativas entre los sitios, con concentraciones particularmente altas en el archipiélago de Cabrera, un área marina protegida (AMP). Se realizó una revisión bibliográfica de la escasa información publicada sobre las especies de la familia Pinnidae a nivel mundial. En comparación con otras especies de bivalvos, como Mytilus galloprovincialis (Mytilidae), la especie bentónica P. nobilis presentó concentraciones más de 30 veces superiores para Cd, Cu y Zn; y hasta 4 y 7 veces para Hg y Pb, respectivamente. La información recabada sobre estas especies que habitan en ecosistemas costeros (Pinnidae vs. Mytilidae) es discutida en el contexto de las actuales estrategias marinas de seguimiento y evaluaciónVersión del editor1,006

    VARIAN CLINAC 6 MeV Photon Spectra Unfolding using a Monte Carlo Meshed Model

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    [EN] Energy spectrum is the best descriptive function to determine photon beam quality of a Medical Linear Accelerator (LinAc). The use of realistic photon spectra in Monte Carlo simulations has a great importance to obtain precise dose calculations in Radiotherapy Treatment Planning (RTP). Reconstruction of photon spectra emitted by medical accelerators from measured depth dose distributions in a water cube is an important tool for commissioning a Monte Carlo treatment planning system. Regarding this, the reconstruction problem is an inverse radiation transport function which is ill conditioned and its solution may become unstable due to small perturbations in the input data. This paper presents a more stable spectral reconstruction method which can be used to provide an independent confirmation of source models for a given machine without any prior knowledge of the spectral distribution. Monte Carlo models used in this work are built with unstructured meshes to simulate with realism the linear accelerator head geometry.Ha recibido financiación de DESARROLLO E IMPLEMENTACION DE UN SISTEMA DE PLANIFICACION RADIOTERAPÉUTICA (TELETERAPIA Y BRAQUITERAPIA) BASADO EN EL MÉTODO MONTECARLO PARA EL HUPLAFE (UNIVERSIDAD POLITECNICA DE VALENCIA), DESARROLLO Y VALIDACION EXPERIMENTAL DE UN SISTEMA DE PLANIFICACION DE TRATAMIENTOS RADIOTERAPEUTICOS UTILIZANDO TECNICAS DE MONTE CARLO (UNIVERSIDAD POLITECNICA DE VALENCIA), Dosimetría in vivo en radioterapia sin filtro aplanador (FFF) (UNIVERSIDAD POLITECNICA DE VALENCIA), MONTE CARLO TREATMENT PLANNING SYSTEM: SOFTWARE PARA EL CALCULO DOSIMETRICO DE ALTA PRECISION EN RADIOTERAPIA. (UNIVERSIDAD POLITECNICA DE VALENCIA) y SISTEMA DE PLANIFICACION DE TRATAMIENTOS EN RADIOTERAPIA BASADO EN EL METODO DE MOTE CARLO Y EL PROCESADO 3D DE IMAGENES MEDICAS (GENERALITAT VALENCIANA)Morató-Rafet, S.; Juste Vidal, BJ.; Miró Herrero, R.; Verdú Martín, GJ. (2017). VARIAN CLINAC 6 MeV Photon Spectra Unfolding using a Monte Carlo Meshed Model. EPJ Web of Conferences. 153(04012):1-7. https://doi.org/10.1051/epjconf/201715304012S171530401

    BREAKING THE PARADIGM: MARINE SEDIMENTS HOLD TWO-FOLD MICROPLASTICS THAN SEA SURFACE WATERS AND ARE DOMINATED BY FIBERS

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    Marine compartments are often considered independent environments in studies on plastic pollution (Ali et al., 2021). Consequently, little is known about microplastic (MPs) distribution amongst those habitats closely linked. Here, we perform an interactive assessment of MPs abundance and composition from the pelagic habitat to beaches integrating shallow seafloor sediments of a coastal Mediterranean marine protected area and evaluating MPs ingestion in holothurians, echinoderms, molluscs, and fishes inhabiting the area. We observed a gradient in the accumulation of MPs from the sea surface (0.17 ± 0.39 MPs/m2) to the seafloor (76 ± 108 MPs/m2) and beach sediment (13418 ± 28787 MPs/m2), with a skip of two orders of magnitude. Microplastic abundances fit with those reported for more anthropized Mediterranean areas and suggest coastal environments as potential debris sinking areas. Fibers dominate all the studied habitats. Holothurians showed the highest general MPs and fibers ingestion occurrence (91%), with greater values (9.48 ± 8.05 MPs/individual and 8.24 ± 7.95 fibers/individual) than those reported previously (Bulleri et al., 2021). Considering ecological key role, species distribution, and MPs ingestion values, we suggest Holothuroidea as suitable bioindicators for plastic pollution, particularly for fibers. Fibers are composed primarily of cellulose acetate (29%), whereas styrofoam of polystyrene (64%), and films, fragments, and filaments of a variable percentage of polyethylene and polypropylene. Differences found in the polymer composition amongst plastics´ morphologies are reflected in the variability observed between habitats and marine organisms. Particularly the polymer composition of fibers coincides with that of one of the MPs ingested by invertebrates. Results suggest that shape is a key plastic characteristic in determining polymer distribution patterns along with habitats and in marine species. Finally, this study highlights once again the importance and urgency of local and global actions needed to mitigate plastic pollution and particularly fiber release into the marine environment

    Multispecies Assessment of Anthropogenic Particle Ingestion in a Marine Protected Area

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    We have applied a multispecies ecosystem approach to analyse the ingestion of anthropogenic particles (AP) in the gastrointestinal tract of 313 individuals (17 fish species and 8 invertebrate species) from pelagic, demersal and benthic habitats in a marine protected area off the Western Mediterranean (Cabrera National Park). We have quantified and characterized the ingestion at several taxonomic levels of fish, sea urchins, sea cucumbers, bivalves, and jellyfish in relation to biotic/abiotic factors based on taxonomic groups, trophic guilds (functional groups) and habitats. AP ingestion occurrence ranged from 26 to 100% with no significant differences among taxonomic groups. The fish within the MPA showed an overall ingestion occurrence ranging from 0 to 100%, the echinoderms from 29 to 100%, the bivalves from 72 to 96% and the jellyfish 36% ingestion. The ecosystem approach applied to evaluate overall AP ingestion within the species reported that for trophic guilds, the omnivorous species ingested the highest amounts of anthropogenic items, while herbivores ingested significantly fewer items than all other trophic guilds. Moreover, no significant differences were found amongst habitats, indicating a homogeneous spatial distribution of APs at all studied habitats. The multispecies approach provided insight into the high APs exposure to species within Cabrera MPA, highlighting the potential harm linked with marine litter that threatens marine biodiversity.En prensa5,82

    A novel ratiometric fluorescent approach for the modulation of the dynamic range of lateral flow immunoassays

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    The majority of lateral flow assays (LFAs) use single-color optical labels to provide a qualitative naked-eye detection, however this detection method displays two important limitations. First, the use of a single-color label makes the LFA prone to results misinterpretation. Second, it does not allow the precise modulation of the sensitivity and dynamic range of the test. To overcome these limitations, a ratiometric approach is developed. In particular, using anti-HIgG functionalized red-fluorescent quantum dots on the conjugate pad (as target dependent labels) and blue-fluorescent nanoparticles fixed on the test line (as target independent reporters), it is possible to generate a wide color palette (blue, purple, pink, red) on the test line. It is believed that this strategy will facilitate the development of LFAs by easily adjusting their analytical properties to the needs required by the specific application
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