208 research outputs found

    Design of a decision support system for combined cycle schemes

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    The growing desire for sponsors of power generation projects to share risk with the lenders has promoted the use of computational tools, simulating and evaluating from a techno-economic viewpoint long-term, high-risk projects. Such models need to include reliable engine diagnostics, life cycle costing and risk analysis technique. This work consisted in designing a Decision Support System (DSS) for the assessment of power generation projects using industrial gas turbines in combined cycle. The software, programmed in Visual Basic in Excel in a windows-frame, runs an external application named Pythia, which has been developed by the Department of Propulsion, Power; Energy and Automotive Engineering at Cranfield University. It can perform gas turbine performance simulations, including off-design conditions, with or without degradation effects providing thus reliable engine diagnostics. Steam cycle models including different heat recovery steam generator configurations have been developed to simulate steam turbine design and off-design performance. Plant performance simulation takes into account off-design conditions, part-load governing strategies and degradation effects. Besides a robust economic mode and a life cycle costing model including maintenance planning assessments offer a wide range of possible operating and economic scenarios. The degree of uncertainty relating to technical and economic factors is assessed using normal distributions, and the level of risk is then evaluated using a risk analysis, technique based upon the Monte Carlo method. The DSS provides all sorts of charts and techno-economic figures in order to support the decision making through an effective user-friendly window-oriented interface.MPhi

    Producing red clover seeds for organic agriculture

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    This tool is a data sheet that can be used by French farmers who produce or want to produce red clover seeds in organic conditions. It provides advice starting from the contract signing to the seed drying, going through the specificities of the crop, the sowing, irrigation, specific pests and their management, and the harvest

    Le cas des marmites modelées e type M4.1. Nouvelles données archéologiques et archéometriques

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    Póster presentado en XI Congrès AIECM3 sur la céramique médiévale et moderne en Méditerranée, Antalya, Turquía, 19-23 octubre 2015Parmi les mobiliers présents en Méditerranée occidentale durant le haut Moyen Âge, la marmite modelée, à base plane et préhensions en languettes, correspondant au type M4.1 a été mise en évidence par S. Gutiérrez Lloret dans le sud-est de la péninsule Ibérique. Elle semble constituer un marqueur chronologique caractéristique des contextes archéologiques des VIIIe, IXe et Xe s. (Gutiérrez Lloret 1996, 2015). Ce type d’ustensile culinaire, assez générique, est présent sur les deux rives de la Méditerranée occidentale. En Espagne, ces marmites présentes dans de nombreux contextes précoces de la période islamique semble toutefois procéder de formes M.1 et M.2, issues de la tradition tardo antique et wisigothique. Dans le nord de l’Afrique, ce type s’inscrit vraisemblablement dans le prolongement des modèles de la Calcitic Ware de l’Antiquité tardive

    Terminal-repeat retrotransposons with GAG domain in plant genomes : a new testimony on the complex world of transposable elements

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    A novel structure of nonautonomous long terminal repeat (LTR) retrotransposons called terminal repeat with GAG domain (TR-GAG) has been described in plants, both in monocotyledonous, dicotyledonous and basal angiosperm genomes. TR-GAGs are relatively short elements in length (<4 kb) showing the typical features of LTR-retrotransposons. However, they carry only one open reading frame coding for the GAG precursor protein involved for instance in transposition, the assembly, and the packaging of the element into the virus-like particle. GAG precursors show similarities with both Copia and Gypsy GAG proteins, suggesting evolutionary relationships of TR-GAG elements with both families. Despite the lack of the enzymatic machinery required for their mobility, strong evidences suggest that TR-GAGs are still active. TR-GAGs represent ubiquitous nonautonomous structures that could be involved in the molecular diversities of plant genomes

    Fine sediment reduces vertical migrations of Gammarus pulex (Crustacea: Amphipoda) in response to surface water loss

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    Surface and subsurface sediments in river ecosystems are recognized as refuges that may promote invertebrate survival during disturbances such as floods and streambed drying. Refuge use is spatiotemporally variable, with environmental factors including substrate composition, in particular the proportion of fine sediment (FS), affecting the ability of organisms to move through interstitial spaces. We conducted a laboratory experiment to examine the effects of FS on the movement of Gammarus pulex Linnaeus (Crustacea: Amphipoda) into subsurface sediments in response to surface water loss. We hypothesized that increasing volumes of FS would impede and ultimately prevent individuals from migrating into the sediments. To test this hypothesis, the proportion of FS (1–2 mm diameter) present within an open gravel matrix (4–16 mm diameter) was varied from 10 to 20% by volume in 2.5% increments. Under control conditions (0% FS), 93% of individuals moved into subsurface sediments as the water level was reduced. The proportion of individuals moving into the subsurface decreased to 74% at 10% FS, and at 20% FS no individuals entered the sediments, supporting our hypothesis. These results demonstrate the importance of reducing FS inputs into river ecosystems and restoring FS-clogged riverbeds, to promote refuge use during increasingly common instream disturbances

    Radiation-induced skin injury in the animal model of scleroderma: implications for post-radiotherapy fibrosis

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    <p>Abstract</p> <p>Background</p> <p>Radiation therapy is generally contraindicated for cancer patients with collagen vascular diseases (CVD) such as scleroderma due to an increased risk of fibrosis. The tight skin (TSK) mouse has skin which, in some respects, mimics that of patients with scleroderma. The skin radiation response of TSK mice has not been previously reported. If TSK mice are shown to have radiation sensitive skin, they may prove to be a useful model to examine the mechanisms underlying skin radiation injury, protection, mitigation and treatment.</p> <p>Methods</p> <p>The hind limbs of TSK and parental control C57BL/6 mice received a radiation exposure sufficient to cause approximately the same level of acute injury. Endpoints included skin damage scored using a non-linear, semi-quantitative scale and tissue fibrosis assessed by measuring passive leg extension. In addition, TGF-β1 cytokine levels were measured monthly in skin tissue.</p> <p>Results</p> <p>Contrary to our expectations, TSK mice were more resistant (i.e. 20%) to radiation than parental control mice. Although acute skin reactions were similar in both mouse strains, radiation injury in TSK mice continued to decrease with time such that several months after radiation there was significantly less skin damage and leg contraction compared to C57BL/6 mice (p < 0.05). Consistent with the expected association of transforming growth factor beta-1 (TGF-β1) with late tissue injury, levels of the cytokine were significantly higher in the skin of the C57BL/6 mouse compared to TSK mouse at all time points (p < 0.05).</p> <p>Conclusion</p> <p>TSK mice are not recommended as a model of scleroderma involving radiation injury. The genetic and molecular basis for reduced radiation injury observed in TSK mice warrants further investigation particularly to identify mechanisms capable of reducing tissue fibrosis after radiation injury.</p

    Knowledge and health care resource allocation: CME/CPD course guidelines-based efficacy.

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    BACKGROUND: Most health care systems consider continuing medical education a potential tool to improve quality of care and reduce disease management costs. Its efficacy in general practitioners needs to be further explored. OBJECTIVE: This study assesses the effectiveness of a one-year continuing medical education/continuing professional development course for general practitioners, regarding the improvement in knowledge of ARIA and GINA guidelines and compliance with them in asthma management. METHODS: Sixty general practitioners, covering 68,146 inhabitants, were randomly allocated to continuing medical education/continuing professional development (five residential events +four short distance-learning refresher courses over one year) or no training. Participants completed a questionnaire after each continuing medical education event; key questions were repeated at least twice. The Local Health Unit prescription database was used to verify prescription habits (diagnostic investigations and pharmacological therapy) and hospitalizations over one year before and after training. RESULTS: Fourteen general practitioners (46.7%) reached the cut-off of 50% attendance of the training courses. Knowledge improved significantly after training (p < 0.001, correct answers to key questions +13%). Training resulted in pharmaceutical cost containment (trained general practitioners +0.5% vs. controls +18.8%) and greater attention to diagnosis and monitoring (increase in spirometry +63.4%, p < 0.01). CONCLUSION: This study revealed an encouraging impact of educational events on improvement in general practitioner knowledge of guidelines and daily practice behavioral changes. Long-term studies of large populations are required to assess the effectiveness of education on the behavior of physicians in asthma management, and to establish the best format for educational events

    Benthic and Hyporheic Macroinvertebrate Distribution Within the Heads and Tails of Riffles During Baseflow Conditions

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    The distribution of lotic fauna is widely acknowledged to be patchy reflecting the interaction between biotic and abiotic factors. In an in-situ field study, the distribution of benthic and hyporheic invertebrates in the heads (downwelling) and tails (upwelling) of riffles were examined during stable baseflow conditions. Riffle heads were found to contain a greater proportion of interstitial fine sediment than riffle tails. Significant differences in the composition of benthic communities were associated with the amount of fine sediment. Riffle tail habitats supported a greater abundance and diversity of invertebrates sensitive to fine sediment such as EPT taxa. Shredder feeding taxa were more abundant in riffle heads suggesting greater availability of organic matter. In contrast, no significant differences in the hyporheic community were recorded between riffle heads and tails. We hypothesise that clogging of hyporheic interstices with fine sediments may have resulted in the homogenization of the invertebrate community by limiting faunal movement into the hyporheic zone at both the riffle head and tail. The results suggest that vertical hydrological exchange significantly influences the distribution of fine sediment and macroinvertebrate communities at the riffle scale
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