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See detailAharonov-Bohm oscillations of bosonic matter-wave beams in the presence of disorder and interaction
Chrétien, Renaud ULg; Dujardin, Julien; Petitjean, Cyril ULg et al

Poster (2016, May 18)

We study the one-dimensional (1D) transport properties of an ultracold gas of Bose-Einstein condensed atoms through Aharonov-Bohm (AB) rings. Our system consists of a Bose-Einstein condensate (BEC) that ... [more ▼]

We study the one-dimensional (1D) transport properties of an ultracold gas of Bose-Einstein condensed atoms through Aharonov-Bohm (AB) rings. Our system consists of a Bose-Einstein condensate (BEC) that is outcoupled from a magnetic trap into a 1D waveguide which is made of two semi-infinite leads that join a ring geometry exposed to a synthetic magnetic flux φ. We specifically investigate the effects both of a disorder potential and of a small atom-atom contact interaction strength on the AB oscillations. The main numerical tools that we use for this purpose are a mean-field Gross-Pitaevskii (GP) description and the truncated Wigner (tW) method. We find that a correlated disorder suppress the AB oscillations leaving thereby place to weaker amplitude, half period oscillations on transmission, namely the Aronov-Al’tshuler-Spivak (AAS) oscillations. The competition between disorder and interaction leads to a flip of the transmission at the AB flux φ = π. This flip could be a possible preliminary signature of an inversion of the coherent backscattering (CBS) peak. Our study paves the way to an analytical description of the inversion of that peak. [less ▲]

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See detailCan tropical basil be integrated in vegetable crop pest management?
Yarou, Boni Barthélémy ULg; Verheggen, François ULg; Heuskin, Stéphanie ULg et al

Poster (2016, May 17)

To address human and environmental health issues related to the use of synthetic pesticides, it is important to explore other ecological pest management approaches. Within this context, a study was ... [more ▼]

To address human and environmental health issues related to the use of synthetic pesticides, it is important to explore other ecological pest management approaches. Within this context, a study was conducted to evaluate the toxic and repellent effect of Ocimum gratissimum L. (Lamiaceae) on Myzus persicae S. (Aphididae). The toxicity of O. gratissimum essential oil (EO) was evaluated on M. persicae comparing 3 concentrations (0.001%; 0.01% and 0.1%) to a control (15% sucrose). Mortality rate and fecundity were assessed for each concentration. The observations were made daily, for 4 days, on 12 replicates per treatment. To test the repellent effect of O. gratissimum plants, 2 treatments were compared: a group of 8 Amaranthus cruentus L. (Amaranthaceae) plants with 1 plant of O. gratissimum in the middle and a group of 9 A. cruentus plants (control). The distribution of aphids was analyzed 12 days after the middle plant infestation (20 aphids per plant) for each treatment (6 replicates per treatment). O. gratissimum EO was found toxic from a concentration of 0.01%, with a mortality rate of 34% versus 12% for the control ; The fecundity felt from 30 larvae after 4 days (control) to 15 larvae for the 3 doses of the EO. The analysis with the generalized linear mixed model with Poisson error distribution followed by Turkey test (5 %) showed that EO is significantly more toxic than the control, both for mortality and fecundity (p <0.001). In association test, the population of M. persicae (15 aphids per plant) was significantly (p<0,001) lower when A. cruentus plants was associated with O. gratissimum plant than with the control (22 aphids per plant). Furthermore, the population increases gradually as one moves away from the infestation point in association test whereas it decreases in the control. With regards to these results, it appears that O. gratissimum has biocide effects on M. persicae. This plant may be used in an integrated pest management strategy in the production of vegetable to reduce the use of synthetic pesticides and avoid chemicals residues. [less ▲]

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See detailFUNCTIONAL SPECIFICATION METHODOLOGY FOR AN ARCHITECTURAL MODELER SUPPORTING A MODULAR CONSTRUCTIVE SYSTEM
Boulanger, Christelle ULg; Rahhal, Anabelle ULg; Delfosse, Vincent ULg et al

in Design2016 (2016, May 16)

This article presents a methodological approach which helped the software development of an architectural modeler that aims to support the life cycle of buildings with a modular construction system. The ... [more ▼]

This article presents a methodological approach which helped the software development of an architectural modeler that aims to support the life cycle of buildings with a modular construction system. The modeler assists the building composition processes, the production of useful documents like drawing plans, quantities and specifications, and the evaluation of the thermal performance of the building at any phase of its design. Conducted within a multidisciplinary team of architects engineers, computer engineers and ergonomists, this methodology is based on a constant interaction between the various skills, so that the different perspectives are systematically integrated into the decision process. The methodology is based on the analysis of three fields of functions (composition - production and evaluation) which are considered simultaneously through a theoretical framework stemming from ergonomics: Activity Theory [Engeström 1987]. At first, the software development context is presented. Then, the choice of the Activity Theory as a framework for the analysis will be motivated. The next section relates the multiple concepts of the methodology to each others, in order to identify the principles as well as the inputs and the outputs. Each step in its implementation is then described, followed by the results in terms of the software interface. Finally, the discussion that will follow will consider the contributions and limitations of this methodological approach in the understanding of a system, in order to offer an efficient IT support. [less ▲]

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See detailMonstruosité cinématographique : déployer l’écart
Jousten, Lison ULg

Scientific conference (2016, May 13)

La communication revient sur la possibilité d’étudier autrement la monstruosité cinématographique, en effectuant un pas de côté par rapport aux approches qui ont abordé le monstre comme motif. Elle ... [more ▼]

La communication revient sur la possibilité d’étudier autrement la monstruosité cinématographique, en effectuant un pas de côté par rapport aux approches qui ont abordé le monstre comme motif. Elle propose de penser l’écart dans l’écart, en déployant cette notion matricielle à au moins trois niveaux : dans la figure même du monstre, dans la nature des films envisagés, ainsi que dans la constitution du corpus. [less ▲]

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See detailVivre et faire vivre la transdisciplinarité. Retour d'expérience du cours "Approche intégrée d'une question d'environnement"
Denayer, Dorothée ULg; Melard, François ULg; Semal, Nathalie ULg

Conference (2016, May 13)

Cette communication présente la démarche pédagogique qui a mené un collectif d'enseignants, à la recherche d'une approche intégrée des questions d'environnement au développement d’une approche ... [more ▼]

Cette communication présente la démarche pédagogique qui a mené un collectif d'enseignants, à la recherche d'une approche intégrée des questions d'environnement au développement d’une approche d’apprentissage où l'entrée des publics concernés dans le dispositif d'apprentissage (Public-based-learning) permettent de faire vivre plutôt que d'enseigner aux étudiants la transdisciplinarité. Cette communication, centrée sur le collectif enseignant, developpe la dimension fondamentalement expérientielle et pratique de l’interdisciplinarité et son ancrage dans un certain type d’engagement du collectif.] [less ▲]

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See detailApproches intégrées en Sciences Pharmaceutiques
Servais, Anne-Catherine ULg; Ziemons, Eric ULg

Conference (2016, May 13)

Detailed reference viewed: 13 (1 ULg)
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See detailSpatial Analysis of the Landslide Risk in the Cameroon Volcanic Line (CVL)
Mukenga, Williams ULg; Havenith, Hans-Balder ULg; Medjo Eko, Robert et al

Poster (2016, May 12)

Landslides are recognized as important geomorphologic process due to the role they play in the development of hill slopes in mountainous regions, and to related socio-economic consequences. There are many ... [more ▼]

Landslides are recognized as important geomorphologic process due to the role they play in the development of hill slopes in mountainous regions, and to related socio-economic consequences. There are many causes of landslides and their distribution varies with the changing conditioning factors. Slope stability depends on a number of causative factors and the knowledge of these variables can help to predict the type of landslide expected in the future. In this study, past landslide activity and triggering factors will be used to assess mass movement hazards along the Cameroon Volcanic Line (CVL). Spatial aspects will be studied in terms of landslide susceptibility maps that are important for development planning and disaster management. The current synthesis of landslide susceptibility map at regional scale is based on a literature review to inventory passed mass movement impacts, on the detection of landslide features from Google Earth imagery, combined with spatial analysis using Geographical Information Systems (GIS) and remote sensing. One of the most critical stages in landslide susceptibility mapping is the selection of landslide pre-conditioning, conditioning and triggering factors and weighting of the selected causative factors in accordance to their influence on slope stability. Google earth helps for delineating past (but recent) and present landslide activity whereas GIS is suitable when deriving static factors (slope aspect and surface curvature) and time-dependent factors (annual precipitation and changing groundwater table level) that are needed to produce landslide susceptibility maps. Landslide susceptibility mapping is based on the assumption that future landslides will occur under similar circumstances as past and present mass movements. Different methods, including the weight of evidence methods, are used for landslide susceptibility mapping along the Cameroon Volcanic line, as the area is known to be highly susceptible to landslide occurrences. [less ▲]

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Peer Reviewed
See detailModelling nitrogen incorporation by primary producers of a Mediterranean coastal area
Elkalay, Khalid; Frangoulis, Constantin; Richir, Jonathan ULg et al

Conference (2016, May 11)

The aim of this study was to simulate the uptake flow of nitrogen (gN m-2) of P. oceanica meadow for 4 primary producers of the bay of Calvi (Corsica, France) (phytoplankton, macro-algae, the Posidonia ... [more ▼]

The aim of this study was to simulate the uptake flow of nitrogen (gN m-2) of P. oceanica meadow for 4 primary producers of the bay of Calvi (Corsica, France) (phytoplankton, macro-algae, the Posidonia oceanica leaves and their epiphytes). The model developed for this purpose simulates the evolution of nitrogen incorporation. The effect of the light intensity, and the water column temperature and concentration in internal and external nitrogen on nitrogen incorporation by the 4 primary producers is modeled. Thus, the incorporation rate of both NO3-and NH4+by phytoplankton was more important than for benthic producers. Macro-algae incorporations had intermediate incorporation rates between the ones of, the phytoplankton and P. oceanic leaves and their epiphytes. The incorporation of NH4+ by the phytoplankton is higher than the incorporation of NO3-. The model appears well adapted to establish the main environmental factors that determine the incorporation of inorganic nitrogen by the various primary producers. It is also able to represent the relative importance of nitrogen incorporation by the various producers. [less ▲]

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See detailHow to specify the environmental footprint of electricity? A methodological approach
Belboom, Sandra ULg; Léonard, Angélique ULg

Conference (2016, May 09)

When assessing the environmental footprint of a product or an industrial process, ma-jor impacts in climate change and resources depletion are usually linked to direct or indi-rect energy consumptions ... [more ▼]

When assessing the environmental footprint of a product or an industrial process, ma-jor impacts in climate change and resources depletion are usually linked to direct or indi-rect energy consumptions. Focusing on electricity generation, largely dispersed results can appear for the concerned impact categories depending on the energy mix taken into account. An accurate knowledge of the mix is of major importance for the prediction of the environmental footprint of electricity. As this mix changes from one country to another and through time, regular update is needed to obtain an accurate value of impact for the studied product. Another criteria to also take into account is the specific technology used to generate electricity depending on the primary energy (gas, coal, uranium, sun, wind, etc.). This study aims to generate a simplified tool, containing sufficient data to assess, within a range of 10 % uncertainty, the value of the environmental footprint of electricity, based on a limited amount of accessible parameters. The global life cycle of electricity generation is taken into account, from the resources extraction to the end-of-life. This is essential to be able to compare, on a same basis, the renewable and classical resources for electricity generation. The functional unit of this study for numerical applications is 1 MWhe. To achieve our goal, the following methodological approach has been pursued. First, the energy mix for electricity generation has been collected trough years for different countries. Then a deeper study of specific technologies relative to each kind of primary energy consumption has been performed. Meta-analyses relative to LCA results have been studied to highlight the main important criteria of these technologies. Then, the amount of needed data for the environmental assessment of these technologies has been reduced to the main important ones. The step further is about the use of these data to obtain an available tool to predict the environmental footprint of electricity depending mainly on the energy mix and used technologies. The environmental impact of 1 MWhe can then be easily calculated using this tool in several categories as climate change, acidification, ozone layer depletion, etc. using the ILCD method. Concerning the resources depletion assessment, all available methodolo-gies have been studied with a specific focus on the CEENE method using an exergetic assessment of resources. This method allows the highlighting of the use of energy and all types of resources (fossil, renewable like wind, sun or land). This perspective can also be used to discriminate several resources for the electricity production. A comparison of the results obtained using resources impact methods has then been performed and some challenges concerning the use of existing impact pathways have been highlighted as well as some perspectives to tackle them. This research has been supported by the Public Service of Wallonia – Department of Energy and Sustainable Building within the framework of the ECEB project [less ▲]

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See detailImproving probiotic viability and functionality by bioreactors engineering
Nguyen, Huu Thanh ULg

Doctoral thesis (2016)

There is a growing market for probiotic bacteria, but their production is still the subject to technical limitations, i.e. susceptibility to the stress conditions found during upstream and downstream ... [more ▼]

There is a growing market for probiotic bacteria, but their production is still the subject to technical limitations, i.e. susceptibility to the stress conditions found during upstream and downstream operations. In this work, we have investigated the effect of cultivation and drying conditions on Bifidobacterium bifidum MG 25628, a probiotic bacteria being particularly sensitive to bioprocessing conditions. Previous results have shown that microbial physiology, and the ability of microbes to cope with stress, is dependent of the growth rate and the growth phase. It is also known that the preliminary exposure of microbial cells to sub-lethal stress enhance its robustness. Accordingly, the effect of the exposure of B. bifidum in a two-compartment reactor designed in order to expose the strain to different temperature conditions was investigated. We found that the exposure of B. bifidum at 42°C for 1h at the onset of the stationary phase enhanced significantly survival after freeze-drying. It appeared that the increase in cell survival was attributed to the induction of the synthesis and an exopolysaccharide layer surrounding the cells. The method involving the exposure of the strain to sub-lethal temperature stress was further successfully scaled-up to a bioreactor volume of 2000 L. EPS synthesis can also be stimulated by sparing the bioreactor with carbon dioxide. In this context, we investigated the EPS yield in two specific bioreactor designs for the intensification of the CO2 gas-liquid mass transfer, i.e. a trickle bed and a falling-film microreactor. Depending of the operating conditions, these two bioreactor configurations led to a significant improvement in EPS synthesis (around 21 g/L). Extensive comparative proteomic analysis confirmed the impact on CO2 mass transfer on cell physiology, notably by enhancing the intracellular concentration of two key enzymes implied in carbonate uptake, i.e. phosphoenolpyruvate carboxylase and carbamoyl phosphate synthase. Taken altogether, these results point out that biochemical engineering parameters can be used as a very efficient strategy for improving probiotic robustness. Additionally, this non-GMO approach is more suited to the consumer expectations. [less ▲]

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See detailA class of valid inequalities for multilinear 0-1 optimization problems
Crama, Yves ULg; Rodriguez Heck, Elisabeth ULg

E-print/Working paper (2016)

This paper investigates the polytope associated with the classical standard linearization technique for the unconstrained optimization of multilinear polynomials in 0-1 variables. A new class of valid ... [more ▼]

This paper investigates the polytope associated with the classical standard linearization technique for the unconstrained optimization of multilinear polynomials in 0-1 variables. A new class of valid inequalities, called 2-links, is introduced to strengthen the LP relaxation of the standard linearization. The addition of the 2-links to the standard linearization inequalities provides a complete description of the convex hull of integer solutions for the case of functions consisting of at most two nonlinear monomials. For the general case, various computational experiments show that the 2- links improve both the standard linearization bound and the computational performance of exact branch & cut methods. The improvements are especially significant for a class of instances inspired from the image restoration problem in computer vision. The magnitude of this effect is rather surprising in that the 2-links are in relatively small number (quadratic in the number of terms of the objective function). [less ▲]

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See detailDepositional Sequences of the Late Pleistocene Shoreline System, Bor Basin, Southern-Central Anatolia: Implications for Reconstructing Lake Level Changes
Bayer Altın, Türkan; El Ouahabi, Meriam ULg; Fagel, Nathalie ULg

Conference (2016, May 08)

The Bor Basin is located in the east part of the Konya-Ereğli Plain occupied by Pleistocene lake (Fig. 1). Paleo-shoreline deposits rising western margins of the basin marked the former extent of a now ... [more ▼]

The Bor Basin is located in the east part of the Konya-Ereğli Plain occupied by Pleistocene lake (Fig. 1). Paleo-shoreline deposits rising western margins of the basin marked the former extent of a now desiccated Late Pleistocene Lake. This study evaluates the former lake level changes and the sequential evolution of a shoreline system that developed at the western margin with lacustrine fills of the Bor paleolake near Zengen settlement. The fills belongs to alluvial fans formed by streams coming from the high volcanic mountains located within the northern part of the basin. The sediment sequence of the fan reflects receded and extended levels of the former lake. 23 samples were obtained at the sand-quarry representing of various facies of the lacustrine fills. These samples were analyzed for mineralogical characterization, using XRD and their CaCO3 values were quantified. According to analysis, three evident different phases of weathering were distinguished in this deposit (Fig. 2). Weathering conditions occurred at the bottom of the profile (level 7) with the appearance of the vermiculite and illite/smectite mixed layer clays. Aridification phases occurred at the level of sample 16 with the appearance of the palygorskite. At the shallow levels from the samples 21 to 22, another aridification phase occurred attested by the appearance of the palygorskite, the mixed layers clays (illite/smectite) and the neoformation of the chlorite by weathering. The palygorskite occurrence showed only in the clay fraction (<2µm) associated with dolomite levels which support its secondary formation during dry periods and pedogenetic transformation. Pedogenesis conditions were attested also by the presence of the mixed layers clays at those levels. [less ▲]

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See detailCatégoriser les effets autodéclarés de la formation technico-pédagogique des enseignants – La grille de codage CInOpTIC
Van de Poël, Jean-François ULg; Verpoorten, Dominique ULg

Conference (2016, May 05)

Cette communication présente une démarche de conception, de validation et d’utilisation d’une grille de codage destinée à aider le centre d’enseignement et d’apprentissage de l’Université de Liège (IFRES ... [more ▼]

Cette communication présente une démarche de conception, de validation et d’utilisation d’une grille de codage destinée à aider le centre d’enseignement et d’apprentissage de l’Université de Liège (IFRES-ULg – Belgique) à repérer les effets des séances de formation technopédagogique qu’il donne à plus de 150 enseignants par an dans le cadre des formations pédagogiques obligatoires pour les nouveaux encadrants. Le matériel qui a servi à cette démarche est constitué des rapports réflexifs rédigés par les participants à la fin de leur cycle de 30 h de formation (plus de 380 rapports ont été analysés sur une période de 3 ans). CInOpTIC est passé par un processus de validation mené avec 6 conseillers pédagogiques de divers horizons. Elle impliquait une série de mouvements de va-et-vient entre les données et les tentatives de catégorisation. L’acronyme CInOpTIC englobe 3 types d’effets trouvés dans les rapports : la prise de Conscience (sensibilisation), l’intention (de l’utilisation de l’apprentissage amélioré par la technologie), et l’opérationnalisation (mesures déjà prises) concernant les TIC. Le processus de validation a également enrichi chaque type d’effet avec des critères de définition plus pointus qui devraient faciliter encore davantage son utilisation future. [less ▲]

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See detailCrystallization behavior of neutralized and bleached shea butter under dynamic conditions
Gibon, V.; Dijckmans, P.; Blecker, Christophe ULg et al

Poster (2016, May 01)

Detailed reference viewed: 19 (3 ULg)
See detailShakespeare and Belgium
Hamélius, Paul ULg

in Gollancz, Israel; McMullan, Gordon (Eds.) A Book of Homage to Shakespeare (2016)

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See detailModelling and Emulation of an Unbalanced LV Feeder with Photovoltaic Inverters
López-Erauskin, Ramón; Gyselinck, Johan; Olivier, Frédéric ULg et al

in Proc. of 8th IEEE Benelux Young researchers symposium in Electrical Power Engineering (2016, May)

In this paper, the penetration of grid-connected pho- tovoltaic systems is studied, experimentally tested and compared to simulation results. In particular, how the inverse current flow and unbalance ... [more ▼]

In this paper, the penetration of grid-connected pho- tovoltaic systems is studied, experimentally tested and compared to simulation results. In particular, how the inverse current flow and unbalance situations affect the voltage in the low-voltage grid. Thus, a test platform has been developed for obtaining experimental results with grid-tied commercial inverters. Photo- voltaic arrays are emulated and subjected to different irradiance profiles and the inverters are controlled to produce at different power conditions. A model has been developed in order to repro- duce the same operating conditions and working environment. Simulations are performed with the software PowerFactory and the results compared to the experimental ones. [less ▲]

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See detailA Comparison of 3D Methods for Identifying the Stance Phase in Treadmill Running for Both Rearfoot and Forefoot Runners
Deflandre, Dorian ULg; Schwartz, Cédric ULg; Weertz et al

in Journal of sports Science (2016), 4

We compared six 3D methods, OptoGait, and Myotest Run for the determination of contact time for runners with different foot strike patterns. Twenty male participants were divided into two groups: the heel ... [more ▼]

We compared six 3D methods, OptoGait, and Myotest Run for the determination of contact time for runners with different foot strike patterns. Twenty male participants were divided into two groups: the heel group, who attack the ground with the heel (n = 12), and the toe group, who attack the ground with the middle/front of the foot (n = 8). They performed trials at speeds of 8 km/h then 16 km/h. To detect foot strike, the use of peak velocity of 3D markers located on the heel, the fifth metatarsal, and the great toe provided the best results for both groups. To detect the toe off, the minimum vertical position of a 3D marker placed in line with the great toe gave the most satisfactory results for both groups. In this way, the values of contact time measured with the 3D methods are consistent. Values measured with OptoGait appear consistent too, while those of the Myotest Run underestimate the contact time for both speeds. 3D analysis provides interesting opportunities for calculation of contact time for both rearfoot and forefoot runners, using specific peak velocities to determine foot strike and marker displacement to determine toe off. [less ▲]

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