16 research outputs found

    On POD analysis of PIV measurements applied to mixing in a stirred vessel with a shear thinning fluid

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    P.O.D. technique is applied to 2D P.I.V. data in the field of hydrodynamics in a mixing tank with a Rushton turbine and a shear thinning fluid. Classical eigen-value spectrum is presented and phase portrait of P.O.D. coefficients are plotted and analyzed in terms of trailing vortices. A spectrum of dissipation rate of kinetic energy is introduced and discussed. Length scales associated to each P.O.D. modes are proposed

    Flood vulnerability and resilience in peri-urbanizing Vietnam : a case study from Ninh Binh province

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    Peri-urban areas in Vietnam are caught between development and conservation needs, between economic development and environmental protection, between cultural preservation and sustainable development. This chapter/article examines vulnerabilities and challenges from flooding in peri-urban communities of the city of Ninh Binh, focusing on: (a) local socioeconomic development policy and the establishment of the Khanh Phu Industrial Zone; (b) impacts caused by flooding and lack of regulations, unplanned built environments, and underdeveloped water infrastructure; and (c) the varying adaptations of different social groups of households. It also explores how institutional adaptation programmes together with household responses collectively determine the resilience of the system

    Transformation, adaptation and development: relating concepts to practice

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    In recent years there has been a growing number of academic reviews discussing the theme of transformation and its association with adaptation to climate change. On the one hand this has stimulated exchange of ideas and perspectives on the parameters of transformation, but it has also given rise to confusion in terms of identifying what constitutes a non-incremental form of adaptation on the ground. What this article aims to do instead is help researchers and practitioners relate different interpretations of transformation to practice by proposing a typological framework for categorising forms of change that focuses on mechanisms and objectives. It then discusses how these categorisations link to the broader conceptions and critiques noted above, with the idea that this will enable those who seek to analyse or plan adaptation to better analyse what types of action are potentially constitutive of transformation. In doing so, it should equally assist in the identification and specification of critical questions that need to be asked of such activity in relation to issues of sustainability and equity. As the term transformation gains ground in discussions of climate change adaptation, it is necessary to take a step back, review quite what commentators mean when they use the word, and consider the implications on people, especially the most vulnerable and marginalised, of “doing” or promoting transformation in its different forms

    Current vulnerability in the Monte Alén - Monts de Cristal landscape, Equatorial Guinea

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    Estimation of wind energy over roof of two perpendicular buildings

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    WOS:000349732100006International audienceWind energy development in a built up environment will be an important subject for future sustainable cities. Maturing CFD technology is making more wind flow simulation experiments available, which can be validated by in situ and wind tunnel measurements. Starting from research on wind accumulation by the Venturi effect in built environment, this paper tries to establish the relationship between wind energy potential and the configuration of two perpendicular buildings by performing parametric CFD wind tests. Two reference buildings (width x length x height = 6 m x 15 m x 10 m) forming a symmetrical corner are chosen and different building lengths, widths, heights, corner separation distances, angles of inlet and altitudes of assessment are considered. Results show that, in converging inlet mode, wind energy potential over the roof generally increases sensibly as the corner separation becomes larger, while in diverging inlet mode it decreases rather slowly with corner enlargement. Meanwhile, compared with a single, isolated reference building, most of the corner configuration cases studied here show greater wind energy density over the roof. (C) 2014 Elsevier B.V. All rights reserved

    How Mixing and Light Heterogeneity Impact the Overall Growth Rate in Photobioreactors

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    The microalgae growth rate in photobioreactors responds with inertia to light stimuli. Here, light variations experienced by the algae are accessed through a coupling of an irradiance field calculation and a Lagrangian particle tracking. The response of algae to fluctuating light is then described by a relaxation model involving a single time constant, the value of which is identified from published data. The overall growth rate is calculated as the sum of individual growth rates of all particles. Instantaneous adaptation and full integration asymptotic behaviors are recovered whilst a finite time constant reveals that the overall growth rate is dependent both on mixing and light distribution. This methodology thus quantitatively relates the design parameters to the photobioreactor performance
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