Last 7 days
Bookmark and Share    
Full Text
See detailMémoires déclinées
Grandjean, Geoffrey ULiege; Henrard, Gaëlle

Conference given outside the academic context (2017)

Detailed reference viewed: 21 (4 ULiège)
Full Text
See detailLes métiers de l’enseignant chercheur : quelle professionnalisation ?
Hanzen, Christian ULiege

Scientific conference (2017, November 08)

Detailed reference viewed: 29 (3 ULiège)
Full Text
See detailQuelle politique agricole commune aujourd'hui?
Habran, Maxime ULiege

Conference given outside the academic context (2017)

Bilan de l'évolution de la politique agricole commune

Detailed reference viewed: 11 (1 ULiège)
Full Text
See detailLes arbres, ces natures sensibles : Oui, les plantes se parlent
Fauconnier, Marie-Laure ULiege

Article for general public (2017)

Marie-Laure Fauconnier, professeur ordinaire à Gembloux Agro-Bio Tech, ULg. Chimiste, elle mène des recherches dans le domaine des molécules naturelles volatiles émises par le règne végétal.

Detailed reference viewed: 62 (0 ULiège)
Full Text
See detailTime to make a choice between a fully liberal or fully regulated model for the electrical industry
Ernst, Damien ULiege

Conference given outside the academic context (2017)

Detailed reference viewed: 35 (2 ULiège)
Peer Reviewed
See detailQuantitative profiling of endogenous polar metabolites from low volumes of blood samples
Kok, Miranda ULiege; Fillet, Marianne ULiege

Conference (2017, November 08)

The etiology of many diseases is not yet completely understood. The involved biological processes might be resolved using a metabolomics approach, because metabolomics provides unique challenging ... [more ▼]

The etiology of many diseases is not yet completely understood. The involved biological processes might be resolved using a metabolomics approach, because metabolomics provides unique challenging opportunities to correlate the metabolome with a physiological or pathophysiological status and provides a vision on the relationships between genes, gene expression, environment and lifestyle. Here, we present the development of two ultra-high performance liquid chromatography (UHPLC) methods coupled to mass spectrometry (MS) for the separation and quantitation of polar metabolites in blood samples. A reversed-phase UHPLC-MS/MS method has been developed to quantify anionic energetic metabolites, whereas hydrophilic interaction chromatography (HILIC)-MS/MS has been used to determine amino acids. Two sample pretreatment procedures have been developed for an optimal recovery of the respective metabolites from whole blood samples. One method involved the precipitation of proteins with organic solvents and acids. In addition, volumetric absorptive microsampling has been used for the sample preparation. Small and accurate quantities of biological fluids (10 or 20 µL) can be collected with this sampling technique, which is of great interest for volume-limited samples or serial collection of samples. The developed methods have been validated and will be applied to determine differences in metabolite concentrations between blood samples from patients and controls. This can lead to a breakthrough in the understanding of diseases and can open new therapeutic perspectives. [less ▲]

Detailed reference viewed: 25 (6 ULiège)
Full Text
See detailOn the design of waste heat recovery organic Rankine cycle systems for engines of long-haul trucks
Guillaume, Ludovic ULiege

Doctoral thesis (2017)

The reduction of CO2 emissions from anthropogenic activities is a strategic goal of the EU in which heavy duty vehicles can contribute in a relevant way. A promising solution is the recovery of the ... [more ▼]

The reduction of CO2 emissions from anthropogenic activities is a strategic goal of the EU in which heavy duty vehicles can contribute in a relevant way. A promising solution is the recovery of the thermal energy initially wasted by the engine, which represents around 60 % of the combustion energy. Transforming this heat into mechanical or electrical energy will thus increase the engine thermal efficiency. The conversion can be performed by means of a thermodynamic cycle (e.g. organic or non-organic Rankine cycles) using the waste heat as energy source, as it has already been developed in large stationary applications. Depending on the operating conditions, fuel consumption, and hence CO2 emissions, can theoretically be reduced by 10% to 15%. Nonetheless, the adoption of such technology in the automotive domain requires specific R&D activities to select the working fluid, the components and the most appropriate system architecture in order to achieve sustainable costs and the required level of reliability, while the transient nature of the heat sources available on the truck must be taken into account to evaluate the resulting fuel economy. In this regards, this thesis, based on experimental studies and simulation models, contributes to the characterization and the design of Waste Heat Recovery Organic Rankine Cycle Systems for engines of long haul trucks. [less ▲]

Detailed reference viewed: 9 (1 ULiège)
Full Text
See detailLe métier d'enseignant : de plus en plus pénible ?
Lafontaine, Dominique ULiege; Quittre, Valérie ULiege

Conference given outside the academic context (2017)

Detailed reference viewed: 12 (0 ULiège)
Full Text
See detailGeneration of unidirectional composite stochastic volume elements from micro-structural statistical information
Wu, Ling ULiege; Bidaine, Benoit; Major, Zoltan et al

Conference (2017, November 07)

The purpose of this work is to generate Stochastic Volume Element (SVE) of unidirectional composites using statistical information obtained from imaging technique in order to study the effect of the micro ... [more ▼]

The purpose of this work is to generate Stochastic Volume Element (SVE) of unidirectional composites using statistical information obtained from imaging technique in order to study the effect of the micro-structure uncertainty on the meso-scale behavior. When considering a homogenization-based multiscale approach, the material properties are obtained at each integration point of a macro-structure from the resolution of a micro-scale boundary value problem. When the separation of scales holds, the macro-point is viewed at the micro-level as the center of a Representative Volume Element (RVE). However, for composite materials which suffer from a large scatter in their constituent properties and microstructure, the separation of scales does not always hold, in particular at the onset of failure, and structural properties exhibit a scatter. In order to predict this scatter, Stochastic Volume Elements (SVE) [1, 2] of unidirectional fiber composite materials should be built from experimental measurements, see Fig. 1(a). Toward this end, statistical functions of the fibers features such as radius, the closest neighboring distance etc. [3] are extracted from several SEM images to generate statistical functions of the micro-structure. The dependent variables are then represented using the copula framework, allowing generating micro-structures, see Fig. 1(b), using an inclusions additive process. Simulations on the generated SVEs are then used to extract the probabilistic meso-scale stochastic behavior. In the future the extracted behaviors will be used to build a stochastic model of homogenized properties based on Mean-Field-Homogenization in order to predict statistical macro-scale behaviors and in particular the failure onset. References [1] Ostoja-Starzewski, M., Wang, X. Stochastic finite elements as a bridge between random material microstructure and global response. Comput. Meth. in Appl. Mech. and Eng. (1999) 168: 35-49. [2] Lucas, V., Golinval, J.-C., Paquay, S., Nguyen, V.-D., Noels, L., Wu, L. A stochastic computational multiscale approach; Application to MEMS resonators. Comput. Meth. in Appl. Mech. and Eng. (2015) 294, 141-167. [3] Vaughan, T.J., McCarthy C.T. A combined experimentalnumerical approach for generating statistically equivalent fibre distributions for high strength laminated composite materials. Compos. Sci. and Tech. (2010) 70, 291-297. [less ▲]

Detailed reference viewed: 20 (1 ULiège)
Full Text
See detailA stochastic 3-scale method to predict the thermo-elastic behaviors of polycrystalline structures
Wu, Ling ULiege; Lucas, Vincent; Golinval, Jean-Claude ULiege et al

Conference (2017, November 07)

The purpose of this work is to upscale material uncertainties in the context of thermo-elastic response of polycrystalline structures. The probabilistic behavior of micro-resonators made of ... [more ▼]

The purpose of this work is to upscale material uncertainties in the context of thermo-elastic response of polycrystalline structures. The probabilistic behavior of micro-resonators made of polycrystalline materials is evaluated using a stochastic multi-scale approach defined using the following methodology. 1. Stochastic volume elements (SVEs) [1] are defined from Voronoi tessellations using experimental measurements of the grain size, orientation, and surface roughness [2]; 2. Mesoscopic apparent thermo-elastic properties such as elasticity tensor, thermal conductivity tensor, and thermal dilatation tensor are extracted using a coupled homogenization theory [3, 4] applied on the SVE realizations; 3. A stochastic model of the homogenized properties extracted from Voronoi tessellations using a moving window technique is then constructed in order to be able to generate spatially correlated meso-scale random fields; 4. These meso-scale random fields are then used as input for stochastic finite element simulations. As a result, the probabilistic distribution of micro-resonator properties can be extracted. The applications are two-fold: 1. A stochastic thermo-elastic homogenization, see Fig. 1(a), is coupled to thermoelastic 3D models of the micro-resonator in order to extract the probabilistic distribution of the quality factor of micro-resonators [5]; 2. A stochastic second-order mechanical homogenization, see Fig. 1(b), is coupled to a plate model of the micro-resonator in order to extract the effect of the uncertainties related to the surface roughness of the polycrystalline structures [2]. References [1] Ostoja-Starzewski, M., Wang, X. Stochastic finite elements as a bridge between random material microstructure and global response. Comput. Meth. in Appl. Mech. and Eng. (1999) 168: 35-49. [2] Lucas, V., Golinval, J.-C., Voicu, R., Danila, M., Gravila, R., Muller, R., Dinescu, A., Noels, L., Wu, L. Propagation of material and surface profile uncertainties on MEMS micro-resonators using a stochastic second-order computational multi-scale approach. Int. J. for Num. Meth. in Eng. (2017). [3] Temizer, I., Wriggers, P. Homogenization in finite thermoelasticity.J. of the Mech. and Phys. of Sol. (2011) 59, 344-372. [4] Nguyen, V. D., Wu, L., Noels, L. Unified treatment of boundary conditions and efficient algorithms for estimating tangent operators of the homogenized behavior in the computational homogenization method. Computat. Mech. (2017) 59, 483-505. [5] Wu, L., Lucas, V., Nguyen, V. D., Golinval, J.-C., Paquay, S., Noels, L. A Stochastic Multi-Scale Approach for the Modeling of Thermo-Elastic Damping in Micro-Resonators. Comput. Meth. in Appl. Mech. and Eng. (2016) 310, 802-839. [less ▲]

Detailed reference viewed: 12 (1 ULiège)
Full Text
See detailEcophysiology of elephants to better understand their crop selection: first results of a case study in Monts de Cristal, Gabon
Ngama, Steeve ULiege

Conference (2017, November 07)

Parasites and hormones are one of the best indicators of animal ecophysiology which clarify the role and importance of physiological processes in the ecological relations of species in their natural ... [more ▼]

Parasites and hormones are one of the best indicators of animal ecophysiology which clarify the role and importance of physiological processes in the ecological relations of species in their natural habitat. As damages on crops are often sources of conflict between humans and elephants in elephant home ranges, few data on the relevance of elephant physiology on crop selection exist. For that we investigate elephant ecophysiology to better understand if their parasitism and stress conditions underlie their crops selection. For that we measured parasite loads and stress hormone levels in feces of some elephants eating banana and others eating natural food. We conducted the study during fifteen months covering five different local seasons of the research site in Mont de Cristal, Gabon. Here we report first results from two seasons. We collected 485 samples of elephant dungs and more than 1200 samples of food items eaten by elephants. While stress levels are not correlated to banana selection, the presence of parasites is. Our results show higher parasite loads in dungs of elephants eating banana than in those of elephants eating natural food resources species. Thus elephants may eat banana more as a medicine item than a food resource. But we still need to confirm these results by assessing this trend over seasons and with reproduction hormones. [less ▲]

Detailed reference viewed: 17 (1 ULiège)
Full Text
Peer Reviewed
See detailGreenland Ice Sheet Surface Mass Loss: Recent Developments in Observation and Modeling
van den Broeke, M.; Box, J.; Fettweis, Xavier ULiege et al

in Current Climate Change Reports (2017)

Surface processes currently dominate Greenland ice sheet (GrIS) mass loss. We review recent developments in the observation and modeling of GrIS surface mass balance (SMB), published after the July 2012 ... [more ▼]

Surface processes currently dominate Greenland ice sheet (GrIS) mass loss. We review recent developments in the observation and modeling of GrIS surface mass balance (SMB), published after the July 2012 deadline for the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR5). Since IPCC AR5, our understanding of GrIS SMB has further improved, but new observational and model studies have also revealed that temporal and spatial variability of many processes are still poorly quantified and understood, e.g., bio-albedo, the formation of ice lenses and their impact on lateral meltwater transport, heterogeneous vertical meltwater transport (‘piping’), the impact of atmospheric-circulation changes and mixed-phase clouds on the surface energy balance, and the magnitude of turbulent heat exchange over rough ice surfaces. As a result, these processes are only schematically or not at all included in models that are currently used to assess and predict future GrIS surface mass loss. [less ▲]

Detailed reference viewed: 31 (3 ULiège)
Full Text
See detailDevelopment of an Interferometric Mass Processing Chain for Multitemporal Ground Deformation Measurements
Libert, Ludivine ULiege; De Rauw, Dominique ULiege; d'Oreye, Nicolas

Conference (2017, November 07)

The main goal of the RESIST project is to understand the mechanisms driving volcanic eruptions and landslides in the Kivu region, on the East African Rift. In order to model both volcanic and landslide ... [more ▼]

The main goal of the RESIST project is to understand the mechanisms driving volcanic eruptions and landslides in the Kivu region, on the East African Rift. In order to model both volcanic and landslide processes, it is necessary to measure ground deformations in the region accurately. For this purpose, both ground-based instruments (e.g. GPS network) and spaceborne data (e.g. optical and SAR images) are used. One aspect of the project focuses on Differential SAR Interferometry (DInSAR), which is a technique used to map ground deformations occurring between two SAR images acquired at different times. It is today a well-mastered technique that offers large spatial coverage with a typical temporal sampling of one to several days, depending on the chosen sensor. In the last years, multitemporal approaches based on DInSAR have been developed, like the Small BAseline Subset (SBAS) [1] and Multidimensional Small BAseline Subset (MSBAS) [2] techniques, or the Persistent Scatterers Interferometry (PSI) [3]. In the framework of RESIST, we use MSBAS to perform ground deformations monitoring along time. The Multidimensional Small BAseline Subset (MSBAS) technique produces 2-D time series of ground deformations by integrating data sets of SAR images acquired by different sensors, with different spatial and temporal sampling, resolutions, incidence angles, wavelengths, pass directions and other varying parameters. By combining at least two data sets with overlapping spatial and temporal coverage and an extended range of look angles, the evolution of deformations in the vertical and west-east directions can be computed by the MSBAS approach [2]. The MSBAS software feeds on a large amount of deformation maps, which are produce by DInSAR. Such an amount of data cannot be produced by hand and that is the reason why we developed an automatic interferometric processing chain meant to produce large amounts of products adequate for multitemporal methods like MSBAS. The interferometric processing is supported by the CSL InSAR Suite (CIS) software developed at Centre Spatial de Liège, which presents the advantages to be fully adaptable to the needs of the MSBAS technique and the thematic specificities. Indeed, numerous options (e.g. adaptive filtering, wide swath interferometry) have been added to the CIS software in the framework of the RESIST project. In a first time, we will briefly present the MSBAS approach and its advantages regarding the ground deformation measurements. In the second part of the presentation, we will introduce the mass processing chain step by step and its functionalities. Critical steps of the chain, like the chosen strategy for the interferometric pairs selection, the integration of Sentinel-1 data or the image interpolation approach, will be presented in more details. Finally, preliminary results of an MSBAS processing over the Bukavu area will be presented. REFERENCES: [1] Berardino, P., Fornaro, G., Lanari, R., and Sansosti, E. (2002). A new algorithm for surface deformation monitoring based on small baseline differential SAR interferograms, IEEE Trans. Geosci. Remote Sens., 40, 11, pp. 2375-2383. doi: 10.1109/TGRS.2002.803792. [2] Samsonov, S., and d’Oreye, N. (2012). Multidimensional time series analysis of ground deformation from multiple InSAR data sets applied to Virunga Volcanic Province, Geophysical Journal International, 191, 3, pp. 1095-1108. doi: 10.1111/j.1365-246X.2012.05669.x [3] Ferretti, A., Prati, C., and Rocca, F. (2001). Permanent scatterers in SAR interferometry, IEEE Trans. Geosci. Remote Sens., 39, 1, pp. 8-20. doi: 10.1109/36.898661. [less ▲]

Detailed reference viewed: 125 (1 ULiège)
See detailAura-t-on toujours besoin de chômeurs en 2030 ?
Orianne, Jean-François ULiege

Scientific conference (2017, November 07)

Detailed reference viewed: 8 (0 ULiège)
Full Text
See detailA TMS–EEG contribution to the multimodal assessment of brain connectivity and consciousness
BODART, Olivier ULiege

Doctoral thesis (2017)

Patients with chronic disorders of consciousness make a challenging population. On the clinical side, establishing an accurate diagnosis is arduous, as the signs of consciousness can be subtle, or even ... [more ▼]

Patients with chronic disorders of consciousness make a challenging population. On the clinical side, establishing an accurate diagnosis is arduous, as the signs of consciousness can be subtle, or even undetectable behaviourally. Both the families and the caregivers need truthful information to make tough decisions about the patient’s management. Transcranial magnetic stimulation, coupled with high-density electroencephalography, is a promising technique to improve our diagnostic ability. The perturbational complexity index derived from this technique is able to distinguish between unconscious and conscious conditions. Its specificity remains to be determined. On the scientific side, the long-standing quest to discover the neural correlates of consciousness is still ongoing. Patients with disorders of consciousness have structural brain damage, and several areas may lose their ability to causally interact in complex patterns with long distance structure. The relation between this ability and structural integrity remains undetermined, despite a vast amount of neuroimaging studies on several networks and connectivities in this population. Our objectives are i) to cross-validate the perturbational complexity index with other neuroimaging techniques, and to determine its specificity, and ii) to determine the relation between global structural integrity and the brain global ability to sustain complex long-range interactions. To do so, we first combined transcranial magnetic stimulation with fluoro-deoxyglucose positron emission tomography, a validated technique studying the brain metabolism, in a population of patients behaviourally characterized by repeated assessments with the gold standard scale, the coma recovery scale – revised. To meet our second objective, we computed and compared the perturbational complexity index and the global fractional anisotropy, a magnetic resonance imaging marker of structural integrity, in patients and in healthy subjects. We found an excellent congruence between electrophysiological and metabolic results in our first study, even in behaviourally unconscious patients showing indirect signs of consciousness. In our second study, we demonstrated that structural integrity largely correlated with the perturbational complexity index, and did not depend on the time since onset or the aetiology. This confirms the diagnostic value of transcranial magnetic stimulation and the perturbational complexity index. It is not only sensitive at the single subject level, but also highly specific. It can detect covert signs of consciousness, as confirmed by other neuroimaging techniques. As such, it could be integrated in diagnostic algorithms and improve their accuracy, leading to better management of these patients. Moreover, the brain’s ability to sustain complex long-range interactions is highly dependant on the global structural integrity. By looking further in detail at the local correlation between these two parameters, our understanding of the emergence of consciousness from fixed structure with variable connectivity would improve. This would be one step forward in the quest for the neural correlates of consciousness. [less ▲]

Detailed reference viewed: 29 (1 ULiège)
Full Text
See detailElectrification and DRC
Ernst, Damien ULiege

Conference given outside the academic context (2017)

Detailed reference viewed: 49 (5 ULiège)
Full Text
Peer Reviewed
See detailPictorial scale of perceived water competences The building of a new tool adapted to the children
Jidovtseff, Boris ULiege; De Sousa Morgado, Liliane ULiege; Sääkslahti, Arja et al

Conference (2017, November 07)

Introduction Researches have demonstrated the interest to develop pictorial instrument for assessing fundamental movement skill perceived competence in young children (1). Perceived competence appears ... [more ▼]

Introduction Researches have demonstrated the interest to develop pictorial instrument for assessing fundamental movement skill perceived competence in young children (1). Perceived competence appears appear at least as important as actual competence as it may more directly affect motivation towards an active behavior (2). For different reasons, it is worth developing such a pictorial instrument for assessing children’s perceived water competencies. With that aim, a collective of researchers have decided to work on the development of such a new tool. Methods The collective of researcher started in 2016 during AIESEP congress in Laramie (USA) and grew up by including additional experts specialized in aquatic skill and/or pictorial scale tools. Videos skype conference and email exchanges were used for communication. Important discussions and decisions concerned the list of aquatic competence skills, the scoring system, the selection of an illustrator and the characteristics of the pictures. In order to build the tool within a reasonable delay, timing with the different actions has been suggested. Results A first list of water competencies has been dressed based on scientific references (3-5). According to these skills, different practical situation have been selected to be included in the pictorial scale. The collective of researcher decided to start with a three level score system including ‘not able’, ‘in progression’ and ‘able’ pictures for each situation. All pictures must be digital in such a way they could be used on paper and/or on computer and android/apple applications. Pictures have to be neutral and to be representative of different cultures and contexts in order to be adapted to all countries and situations. The possibility of having the same image in different cultural contexts is investigated. The different steps in the scale development have been scheduled and will include: content validity, face validity, construct validity, reliability, data collection. Conclusion The development of a pictorial instrument for assessing children perceived water competencies is progressing well and a usable version of the tool should be available by the end of 2017 References 1. Barnett, L. M., Ridgers, N. D., Zask, A., & Salmon, J. (2015). Face validity and reliability of a pictorial instrument for assessing fundamental movement skill perceived competence in young children. Journal of science and medicine in sport, 18(1), 98-102. 2. Barnett, L. M., Morgan, P. J., van Beurden, E., & Beard, J. R. (2008). Perceived sports competence mediates the relationship between childhood motor skill proficiency and adolescent physical activity and fitness: a longitudinal assessment. International journal of behavioral nutrition and physical activity, 5(1), 40. 3. Langendorfer, S. J., & Bruya, L. D. (1995). Aquatic readiness: Developing water competence in young children. Human Kinetics 1. 4. Langendorfer (2015). Changing Learn-to-Swim and Drowning Prevention Using Aquatic Readiness and Water Competence, International Journal of Aquatic Research and Education, 2015, 9, 4-11 5. Quan et al. (2015). Toward Defining Water Competency: An American Red Cross Definition, International Journal of Aquatic Research and Education, 2015, 9, 12-23 [less ▲]

Detailed reference viewed: 14 (0 ULiège)
Full Text
See detailThe 4th power
George, Philippe ULiege

Scientific conference (2017, November 06)

Detailed reference viewed: 12 (1 ULiège)
Peer Reviewed
See detailResource efficiency and circularity in engineering higher education
Attia, Shady ULiege

in Moula, Munjur; Pekka, Oinas; Jaana, Sorvari (Eds.) et al Constructing A Green Circular Society (2017)

Detailed reference viewed: 40 (1 ULiège)
See detailPhotographies clandestines. Les images de la RAF en prison(s).
Hamers, Jérémy ULiege

Scientific conference (2017, November 06)

Detailed reference viewed: 15 (0 ULiège)