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Caractérisation expérimentale et numérique du comportement hydrodynamique d’une hydrolienne à membrane ondulante ArchiMer
Trasch, Martin.
The thesis presented in this document deals with the caracterisation of the behaviour of an undulating membrane tidal energy converter. This kind of device uses the flutter instabilities occurring between a semi-rigid pre-strained membrane and a fluid flow in order to convert the sea currents energy. Above a certain critical flow speed, the structure ondulates, thus activating the linear converters fixed on it. In order to study this system, an experimental model is developped and tested in a flume tank. The power conversion system is simulated by hydraulic dampers. The membrane’s dynamics is analysed in many configurations through trajectory and force measurements, and leads to a parametric study. More realistic flow conditions are also studied, such as...
Tipo: Text Palavras-chave: Énergies marines renouvelables; Hydrolienne; Interaction fluidestructure; Instabilité de flottement; Essais expérimentaux; Particle Image Velocimetry; Modélisation numérique; Méthode vortex; Éléments finis; Corotationnel; Houle; Effet d’échelle; Marine renewable energy; Tidal energy converter; Power takeoff; Fluid-structure interaction; Flutter instability; Experimental trial; Particle Image Velocimetry; Numerical model; Vortex method; Corotational finite elements; Surface wave; Scale effect.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00490/60185/63527.pdf
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Land use impact on soil erosion at different scales in the Brazilian semi-arid Rev. Ciênc. Agron.
Santos,Julio Cesar Neves dos; Andrade,Eunice Maia de; Medeiros,Pedro Henrique Augusto; Guerreiro,Maria João Simas; Palácio,Helba Araújo de Queiroz.
ABSTRACT Erosion and sediment transport processes are strongly dependent on the spatial scale and land use. The objective of this study is to analyse the effects of slash and burn of vegetation followed by grass cultivation for grazing, on the hydrological and sedimentological behaviour at different spatial scales in a semiarid region in Brazil. Rainfall, runoff and soil loss were measured during three years (total of 116 rainfall-runoff events) at three spatial scales: 1 m2 and 20 m2 plots and 2.8 ha watershed. During the first year (2009) the native dry tropical forest/Caatinga vegetation was maintained, whereas on the following years (2010 and 2011) the original vegetation was cleared using slash and burn techniques to grow pasture (Andropogon gayanus...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Hydrological and sedimentological behaviour; Soil loss; Scale effect.
Ano: 2017 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-66902017000200251
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Mudança da composição agrícola em duas regiões de Minas Gerais AgEcon
Santos, Fernando Antonio Agra; Faria, Roberto Araujo de; Teixeira, Erly Cardoso.
This work analyzes the changes in area under cultivation that occurred between 1985 and 1995/1996 in the meso-regions Triângulo Mineiro/Alto Paranaíba and Zona da Mata in the state of Minas Gerais, Brazil. The analysis was conducted in two methodological stages. First, variation in the area under cultivation for a particular crop was disaggregated into variation due to change in regional agricultural scale and variation due to the substitution effect. Second, an econometric model of the crop that had the greatest growth in cultivated area and highest substitution effect index was developed to identify the main factors responsible for these high figures. It is observed that the area under rice cultivation was reduced in all regions, a fact related to the...
Tipo: Journal Article Palavras-chave: Agricultural composition; Scale effect; Substitution effect.; Agribusiness.
Ano: 2008 URL: http://purl.umn.edu/61226
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Scale and scope effects on communities’ values for environmental improvements in the Namoi catchment: A choice modelling approach AgEcon
Mazur, Kasia; Bennett, Jeffrey W..
This report presents results of research designed to investigate variations in willingness to pay (WTP) estimates across different scales and scopes of environmental investments. The goal is to help catchment management authorities better prioritise their natural resource management actions at both catchment and farm levels. Five split samples were used to test for scale and scope effects. A choice-modelling (CM) analysis was used to elicit household WTP for improvements in environmental quality attributes in the Namoi catchment. The approach was developed so that value estimates could be more accurately transferred between different action scopes.
Tipo: Report Palavras-chave: Choice modelling; Scale effect; Scope effect; Embedding; Non-market valuation; Catchment planning; Environment.; Community/Rural/Urban Development; Environmental Economics and Policy; Research Methods/ Statistical Methods.
Ano: 2009 URL: http://purl.umn.edu/94891
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Scale and size effects on dynamic response and damage of glass/epoxy tubular structures ArchiMer
Tarfaoui, Mostapha; Gning, P.b.; Davies, Peter; Collombet, F.
The impact behavior of composite materials has been extensively studied but interest has been centered on flat plates. For underwater applications, thick composite cylinders are employed and several questions must be addressed concerning the influence of accidental impact. The aim of this work is to study the dynamic response of tubular structures. Such structures find many applications but the damage upon impact is not taken into account during their dimensioning. However, at the time of their handling or in service the damage introduced by accidental impact can compromise their capacity to fulfill their function. The cylinders are thick and consist of epoxy matrix and glass fiber reinforcement. After having observed the nature of the damage related to...
Tipo: Text Palavras-chave: Size effect; Scale effect; Damage; Impact; Filament winding.
Ano: 2007 URL: http://archimer.ifremer.fr/doc/2007/publication-2458.pdf
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