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See detailIntegration of Migrants from a comparative perspective
Martiniello, Marco ULg

Scientific conference (2005, May 26)

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See detailIntegration of near-surface geophysical, geological and hydrogeological data with multiple-point geostatistics in alluvial aquifers
Hermans, Thomas ULg

Doctoral thesis (2014)

Alluvial plains constitute essential geological bodies for environmental studies such as contaminated sites remediation, low-enthalpy geothermal energy or groundwater resources. The heterogeneity of these ... [more ▼]

Alluvial plains constitute essential geological bodies for environmental studies such as contaminated sites remediation, low-enthalpy geothermal energy or groundwater resources. The heterogeneity of these deposits governs flow processes and needs to be quantified. A proper description of such complex deposits requires an integrated approach combining geological, geophysical and hydrogeological data. Solving such spatial inverse problems in the Earth Sciences remains a considerable challenge given the large number of parameters to invert for, the non-linearity of forward models and, as a result, the ill-posedness of the problem. Geostatistics is therefore needed to specify prior models, more particularly, information to control the spatial features of the inverse solutions. Two-point geostatistical approaches have been developed to describe the heterogeneity of one geological formation but fail to reproduce the heterogeneity of fluvial deposits with multiple facies. Multiple-point statistics (MPS) introduced the training image (TI) concept to replace the variogram within an extended sequential simulation framework. The use of geophysics to constrain such simulations has been studied in the petroleum industry with wave-based methods (seismic reflection), but little research has been done to assess the use of near-surface potential methods to condition MPS in environmental studies. In this work, we propose to integrate geological (borehole logs), geophysical (electrical resistivity tomography (ERT) profiles) and hydrogeological (hydraulic heads) data within MPS models on the alluvial plain of the Meuse River, Belgium. Potential-based geophysical methods being integrative, they suffer from a relatively poor resolution. We first study how we can improve the informative content of geophysical inversion by including prior information in the ERT inverse problem. Three methods are tested and compared in several field cases, namely the reference model inversion, the structural inversion and the regularized geostatistical inversion. If every method has advantages and drawbacks, the best suited method for the considered problem is the regularized geostatistical method. Electromagnetic borehole logs enable to derive the vertical correlation length of electrical resistivity in the deposits and to subsequently use it to constrain the inversion. In addition to the knowledge of the bedrock position, it enables to retrieve an electrical resistivity distribution of the deposits close to direct observations. This ensures that geophysical models will be informative to constrain MPS simulations. Given the lack of geological and sedimentological data to build accurate TIs, a data base of TIs is built using several different parameters and scenarios. They are all based on a three facies description: clay/loam, sand and gravel corresponding to low, intermediate and high hydraulic conductivity. Then, we develop a methodology to verify the consistency of independently-built TIs with geophysical data. Our methodology starts by creating subsurface models with each TI. From these models we create synthetic geophysical data and from this synthetic data, synthetic inverted models. These models are now compared with a single inverted model obtained from the field survey, allowing for our definition of what is ``consistent''. To that extent, we calculate the Euclidean distance between any two inverted models as well as field data and visualize the results in a 2D or 3D space using multidimensional scaling (MDS). With this technique, it is possible to verify if field cases fall in the distribution represented by synthetic cases, and thus are consistent with them. In a second step, we present a cluster analysis on the MDS-map to highlight which parameters are the most sensitive for the construction of TI. Based on this analysis, a probability of each geological scenario is computed through kernel smoothing of the densities in reduced projected metric space. The integration of hydrogeological data is made through a stochastic inversion method: the probability perturbation method (PPM), using MPS constrained with geophysical data to generate models. The PPM algorithm automatically seeks solutions fitting both hydrogeological data and training-image based geostatistical constraints. Only geometrical features of the model are affected by the perturbation, i.e. we do not attempt to directly find the optimal value of hydrogeological parameters (chosen a priori), but the optimal spatial distribution of facies whose prior distribution is quantified in a training image. Tracing experiments may be used to further constrain hydrogeological models. ERT has proven its ability to monitor salt tracer tests, but few studies have investigated its performances in thermal tracing experiments. In this study, we demonstrate the ability of surface and crosshole ERT to image quantitatively temperature changes during heat injection experiments. Such resistivity data provides important information to improve hydrogeological models. Our study proves that ERT, especially crosshole ERT, is a reliable tool to follow thermal tracing experiments. It also confirms that ERT should be included to in situ techniques to characterize heat transfer in the subsurface and to monitor geothermal resources exploitation. [less ▲]

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See detailIntegration of near-surface geophysical, geological and hydrogeological data with multiple-point geostatistics in alluvial aquifers
Hermans, Thomas ULg; Nguyen, Frédéric ULg

Scientific conference (2011, October 20)

This work takes place in the context of the following PhD research topic. Alluvial plains constitute essential geological bodies for environmental studies such contaminated sites remediation, low-enthalpy ... [more ▼]

This work takes place in the context of the following PhD research topic. Alluvial plains constitute essential geological bodies for environmental studies such contaminated sites remediation, low-enthalpy geothermal energy or groundwater resources. The general objective of this work is to contribute to a better quantification of the heterogeneity of the parameters governing flow and transport processes by combining near-surface geophysics and geostatistics. Two-points geostatistical approaches (variogram based) have been developed to quantify the heterogeneity of one geological formation but fail to reproduce the heterogeneity of fluvial deposits with multiple facies. Multiple-points geostatistics introduced the training image concept to replace the variogram within an extended sequential simulation framework. The role of the training image is to depict the conceptual geological patterns. Previous studies have demonstrated the need for more conditioning data to generate an efficient training image. The use of geophysics in this context has been studied in the petroleum research with wave-based methods (seismic reflection data). However, little research has been done to assess the use of near-surface geophysical measurements, relying on potential and wave methods, to condition multiple-point geostatistics for environmental studies. This research project will focus on three specific objectives. The first will consist in computing conceptual training images from the combination of near-surface geophysics images, geological information and borehole data. The second objective will use these images to build models of the subsurface properties with multiple-point geostatistics conditioned to site-specific near-surface geophysical data and borehole information. Finally, groundwater model parameter estimation will be performed using a geologically consistent perturbation approach based on tracer experiments, using well sampling and time-lapse geophysical data. The approach will be demonstrated on both synthetic benchmarks and real field sites. This presentation shows preliminary research results on the use of combined geophysical techniques to improve geophysical models, the building of geological scenarios (training images) in the Meuse alluvial aquifer and the use of time-lapse ERT data to improve our understanding of hydrogeological reservoirs. [less ▲]

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See detailIntegration of photovoltaic cells in solar drying systems
Bennamoun, Lyes ULg

in Drying Technology (2013), 31(11), 1284-1296

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See detailIntegration of Photovoltaic Panels Into Low-voltage Distribution Networks
Olivier, Frédéric ULg

Master's dissertation (2013)

We address in this thesis the problem of overvoltages caused by photovoltaic (PV) panels in low-voltage networks. As a solution to this problem, we propose new active network management schemes. They work ... [more ▼]

We address in this thesis the problem of overvoltages caused by photovoltaic (PV) panels in low-voltage networks. As a solution to this problem, we propose new active network management schemes. They work by modulating in an ad-hoc way the power injected by the PV inverters into the low-voltage network. Two types of control schemes are studied: centralized ones and distributed ones. The centralized schemes compute the modulation orders by exploiting an optimal power flow formulation of the problem. The distributed schemes are based on simple control logics implemented in the inverters and using only local information. Henceforth, they are less expensive to build than centralized ones. Both types of schemes are tested on a simple test network. The simulation results show that they are indeed able to control the voltages so that they stay within their limits. Moreover, the distributed schemes are shown to perform almost as well as the centralized ones, when using as performance metric the amount of energy curtailed on the PV installations. [less ▲]

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See detailIntegration of quality indices of distribution in benchmarking analysis
Coelli, Tim; Gautier, Axel ULg; Perelman, Sergio ULg et al

Report (2011)

Detailed reference viewed: 16 (7 ULg)
See detailIntegration of quality indices of distribution in benchmarking analysis
Coelli, Tim; Gautier, Axel ULg; Perelman, Sergio ULg et al

Report (2011)

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See detailIntegration of recrystallisation model coupled with an elasto-visco-plastic law - Experimental tests and calibration of this model
Charles, J. F.; Habraken, Anne ULg; Lecomte-Beckers, Jacqueline ULg

in Proceedings of the 2nd ESAFORM Conference on Material Forming (1999)

The recrystallisation model is based on the model developed by Kopp [1,2]. This model is implemented in our finite element code "lagamine" and is coupled with a thermomechanical elasto-visco-plastic law ... [more ▼]

The recrystallisation model is based on the model developed by Kopp [1,2]. This model is implemented in our finite element code "lagamine" and is coupled with a thermomechanical elasto-visco-plastic law. It assumes that each integration point in the mesh is represented by a number of sub-structures with a different volumic recrystallised fraction. In order to be able to calibrate such a model, we need to perform a lot of experimentals tests. Hot compression tests on small cylinder at different temperatures and strain rates are made till strain level from 0.1 up to 0.7. The compressed cylinders are quenched after the tests. A metallographic study of the quenched cylinders gives the recrystallised fraction function of the strain, the strain rate and temperature. So experimental, numerical and metallographic studies of hot compression tests aim the definition of an accurate predictive thermo-mechanic metallurgical model able to stimulate forging processes. [less ▲]

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See detailIntegration of the selective deconvolution algorithm into a multiresolution scheme
Van Droogenbroeck, Marc ULg; Vandendorpe, Luc

in Image Processing: Algorithms and Techniques III (1992, February)

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Peer Reviewed
See detailIntegration of vehicle, propulsion system and separation unit designs for a launcher using in-flight oxygen collection
Bizzarri, Didier; Hendrick, Patrick; Heyen, Georges ULg et al

in AIAA/CIRA 13th International Space Planes and Hypersonics Systems and Technologies Conference (2005, May)

The use of in-flight Oxygen Collection has shown to significantly improve space launcher performance. The conceptual approach followed by the Royal Military Academy of Brussels (RMA) has tried to widen ... [more ▼]

The use of in-flight Oxygen Collection has shown to significantly improve space launcher performance. The conceptual approach followed by the Royal Military Academy of Brussels (RMA) has tried to widen the available design margins in order to reduce the required technological leap and limit the economical risk associated with such a development. The aim of the ESA-funded theoretical and experimental study on an air separation device is to demonstrate the possibility of performing efficient air distillation in a compact rotating column. An integration of the vehicle, propulsion system and separation unit designs is presented aiming to optimise the overall vehicle performance while keeping technological difficulty and system complexity at a reasonable level. Reference vehicles are presented in their specific mission profiles with an emphasis on TSTO’s. Different layouts of the internal energy and mass flowsheets are compared, in order to make best use of the refrigeration capacity of the hydrogen fuel running though the propulsion system during the first phase of the flight considering the separator as a classical distillation column. This analysis provides the requirements in terms of heat exchange capacity, compression ratios and number of so-called transfer units needed in the separator. Here, the system is intentionally kept simple, to limit complexity, but the analysis is thorough and accurate, including, for example, the effect of the presence of argon. An analysis of the separation unit to reach those requirements is proposed. That includes internals, practical building with estimates of pressure drop, separation performance and flow limitation. Analysis of size reduction of the distillation unit from usual 1-g column to the high-g unit is provided as well as the scale up methodology of laboratory results. First experimental results obtained with our centrifugally enhanced distillation separation system are presented and perspectives for a larger on-board operational unit proposed. [less ▲]

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See detailL'intégration par les jeunes des stéréotypes sexistes véhiculés par les médias
Dizier, Céline; Nibona, Marjorie; Willems, Isabelle et al

Report (2007)

Le rapport analyse la manière dont les stéréotypes sexistes sont diffusés dans les médias, notamment par les situations et par l'image. Il présente également une enquête sur les jeunes pour percevoir la ... [more ▼]

Le rapport analyse la manière dont les stéréotypes sexistes sont diffusés dans les médias, notamment par les situations et par l'image. Il présente également une enquête sur les jeunes pour percevoir la façon dont ces stéréotypes sont intégrés ou mis en distance en fonction des pratiques de consommation médiatique mais aussi du contexte. [less ▲]

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See detailIntegration Processes and Policies
Martiniello, Marco ULg; Penninx, Rinus

in Martiniello, Marco; Penninx, Rinus; Kraal, Karen (Eds.) et al Citizenship in European Cities. Immigrants, Local Politics and Integration Policies (2004)

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See detailIntégration régionale et démocratie. Quelques réflexions à partir de la pensée d'Alexis de Tocqueville
Carlier, Jean-Yves ULg

in Revue Burkinabè du droit (2001), (39-40), 9-20

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See detailIntegration sites of BLV provirus in the tumor cell genome : implications for the mechanism of leukemogenesis.
Gregoire, D.; Kettmann, Richard ULg; Couez, D. et al

in Straub, O. C. (Ed.) Proceedings of the Fifth international symposium on bovine leukosisgs (1984)

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See detailL'intégration sociale des immigrés en Espagne
Brey, Elisa ULg

Conference (2009)

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See detailIntegration und Interaktion: Möglichkeiten des Einsatzes von Notebooks und Internet in der regelungstechnischen Lehre
Schumm, Peter; Bullinger, Eric ULg; Schweickhardt, Tobias et al

in at - Automatisierungstechnik (2004), vol.52, no.2

Since a few years high-schools are testing the use of notebooks for teaching purposes and already use them quite successfully. A new approach is to use them also for academic education. In the first part ... [more ▼]

Since a few years high-schools are testing the use of notebooks for teaching purposes and already use them quite successfully. A new approach is to use them also for academic education. In the first part of this article an overview will be given about the concepts of the BMBF-sponsored project Notebook University. The second part describes how notebooks are used in the e-learning project to support the teaching of control theory [less ▲]

Detailed reference viewed: 36 (12 ULg)