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See detailmodelling heat and mass transfer during convective drying of a building material
Kahlerras, Loubna ULg

Conference (2014, August 24)

The purpose of this study is to characterize experimentally the behaviour of a cement mortar during its convective drying. The work presented here focuses on mortars with water-to cement ratios (w/C) of 0 ... [more ▼]

The purpose of this study is to characterize experimentally the behaviour of a cement mortar during its convective drying. The work presented here focuses on mortars with water-to cement ratios (w/C) of 0, 5. The drying tests are realized in a convective dryer designed for the drying of small samples (0 - 8g). Experiences are realized with different conditions of drying air temperature (60, 90 and 130 °C) and velocity (2, 3 and 5 m/s) the results show the influence of temperature and velocity on drying curve. Mathematical models have been used for the description of drying curves. The exponential mathematical model seems the most adequate to describe the drying curves of cement mortars, with correlation coefficients changing with the air temperature and velocity and close to unity. The convective mass and heat transfer coefficients are determined from the experimental data. The results showed that both mass and heat transfer coefficients were affected by the air temperature and velocity. The convective mass transfer coefficient changed from 0.0232m/s at V=2m/s to 0.045m/s at V=5m/s, and from 0.055 m/s at 60°c to 0.023 at 130°c. Heat transfer coefficient changed from 14.767 w/m2°c at V=2m/s to 28.64 w/m2°c at V=5m/s and from 7.71 at 60° c to 14.77 at 130°c The temperature dependency of the two coefficients was expressed using an Arrhenius-type equation and related parameters were deduced [less ▲]

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See detailExperimental study of the drying kinetic of mortar
Kahlerras, Loubna ULg

Conference (2014, August 24)

This work reports the results of an experimental study concerning on one hand the influence of water-to cement ratios (W/C), and the role of aggregates on the other hand on the drying kinetics of cement ... [more ▼]

This work reports the results of an experimental study concerning on one hand the influence of water-to cement ratios (W/C), and the role of aggregates on the other hand on the drying kinetics of cement pastes during thermal drying. Three types of cement pastes were realized and studied; cement pastes with ratios W/C 0.4, W/C 0.5 and mortar with ratio W/C 0.5. These tries present the advantage to reproduce the natural conditions met in the problems of interaction atmosphere and material. Cylindrical samples of cement of size (17 X 13) mm are dried in a convective dryer. The sample is continuously weighed during the drying test and its mass is recorded every 60 s, in the purpose to obtain the drying curves. The results show that the increase of the W/C ratio leads to an increase of the drying rate due to the increase of the initial porosity. The effect of the introduction of aggregates is observable by the comparison of the drying curve obtained for the mortar and the cement pastes. The results show a decrease of the drying kinetics with mortars. The results also show that the air drying temperature has a large impact on the drying process, increasing the temperature leading to significant drying time reduction. The Effective diffusion coefficient is calculated by comparison between the experimental results and the analytical solution of Fick’s equation written for a finite medium. [less ▲]

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See detailThe taste bud and the form. Ethnography of sensory labs
Vangeebergen, Thomas ULg

Conference (2014, August 22)

Sensory analyses present an opportunity to challenge classical dualism, especially when it is about taste. During long-term fieldworks, I accompanied several types of sensory expert panels, which had the ... [more ▼]

Sensory analyses present an opportunity to challenge classical dualism, especially when it is about taste. During long-term fieldworks, I accompanied several types of sensory expert panels, which had the mission to discriminate different sorts of products and define their respective sensory profile. I was interested to observe the period of training to understand how those people had acquired their expertise, and how their attention toward their own sensations were entangled to scientific infrastructures. Using sensory ethnographic methods, I assisted to the emergence of a particular world, in which the classical categories for science practices and taste perception were completely blurred. To establish a common truth, through sturdy and stable categories, appears to be compatible with personal moods and dispositions, singular and hedonic judgments, sociocultural grounded sensorium, contingent elements, and indeterminate parameters. Resorting to standard tests, educated and coached judges, statistical treatments, specific vocabulary, comparisons to physic-chemical analysis and various other apparatuses, these labs tempt to define and assess some food products. The goal of those examinations could be multiple: to outline consumers¿ feelings and choices, to check the quality of production, to search new applications, or to improve a current array. What interested me is the quest to an object practically exploitable in an industrial and commercial context, avoiding all kind of idiosyncratic experiences. In this presentation, I would tempt an analysis of those particular tests, focusing on the double bind of testing products and testing consumers, and searching to assess the causes of organoleptic variability. [less ▲]

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See detailVirus indexing and sanitation of international banana collection: insights from a 5-year collaborative effort
De Clerck, Caroline ULg; Parmenter, Kathleen; Vandenhouwe, Ines et al

Conference (2014, August 14)

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See detailContribution à l'exploration de la structure des sols par microtomographie aux rayons X : vers une amélioration de la modélisation hydropédologique
Beckers, Eléonore ULg

Doctoral thesis (2014)

The aim of this thesis is to tend towards a better representation of soil water horizontal fluxes in hydropedological modelling. Tillage practices result in soil structural modifications which impact soil ... [more ▼]

The aim of this thesis is to tend towards a better representation of soil water horizontal fluxes in hydropedological modelling. Tillage practices result in soil structural modifications which impact soil hydrodynamic behaviour. This study takes place in this context, aiming to understand these modifications using X-ray microtomography (µCT), which allows a more fundamental analysis of soil. Indeed, this tool becomes a key in the field of soil science, giving a direct insight of the internal structure of soil. Besides, anisotropy studies are still rare as tiresome, and this work shows that the current hydrological models are anyway unable to represent it correctly: when it is taken into account, it rests on the hypothesis of a simple ratio between vertical and horizontal conductivity functions. First, microtomography is used supplementary to usual methods for the establishment of hydrodynamic functions near saturation. We showed that the retention curve designed with µCT information is more realistic since it leads to a better estimation of unsaturated hydraulic conductivity. However, these results could be doubtful depending on the different µCT acquisition or processing choices and hypothesis. Particularly, the thresholding step is crucial. Consequently, we propose a new global thresholding method based on the visible part of soil sample porosity. This method has been tested and validated in the context of the present study. This step allows us to use microtomography results to increase our knowledge of soil structure. A principal component analysis on soil pores structural parameters confirms that connectivity, specific surface, volume and radius are key factors for the differentiation of soil horizons texturally similar but structurally different. Our results show that structural parameters have to be taken into account to improve hydropedological modelling, especially if pores orientation is considered. We described thus the relevant parameters that can be obtained with µCT and which could help to better model water fluxes in soil while discussing the remaining limits and uncertainties, about upscaling issues notably. [less ▲]

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See detailExactitude du positionnement numérique des axes de ruissellement dans les bassins versants agricoles
Ouedraogo, Mohamar ULg

Doctoral thesis (2014)

Des études récentes menées en Belgique estiment les dommages causés par les inondations et les coulées boueuses entre 12,5 et 122 millions d’euros par an pour les infrastructures publiques, et entre 1,6 ... [more ▼]

Des études récentes menées en Belgique estiment les dommages causés par les inondations et les coulées boueuses entre 12,5 et 122 millions d’euros par an pour les infrastructures publiques, et entre 1,6 et 16,5 millions d’euros par an pour les habitations. La carte des zones à risque potentiel de ruissellement concentré est l’un des outils mis en place par la Wallonie pour lutter contre ces phénomènes de plus en plus fréquents. Cependant, la résolution (10 × 10 m) du MNT utilisé pour extraire les axes de ruissellement est trop faible pour prendre en compte les détails de la microtopographie (travail du sol, résidus de cultures, cultures…) des parcelles agricoles. De plus, elle ne tient pas compte des incertitudes inévitables, présentes dans les données altimétriques utilisées. L’objectif de cette thèse est d’envisager l’utilisation des nouvelles technologies d’acquisition des données altimétriques de haute densité (plusieurs points/m²), i.e., le scanner laser terrestre (TLS) et la photogrammétrie à partir d’un véhicule non piloté (VNP) pour créer un modèle numérique de terrain (MNT) de meilleure exactitude et de haute résolution spatiale (maille de dimensions ± 1 x 1 m). Cela permet de tenir compte de la variabilité altimétrique des parcelles agricoles, et d’analyser son impact sur le positionnement numérique des axes de ruissellement. Dans un premier temps, un TLS et un VNP à voilure fixe ont été utilisés pour acquérir des données altimétriques sur un bassin versant agricole de 12 ha. Deux logiciels photogrammétriques ont permis de générer le MNTPSC (Agisoft PhotoScan) et le MNTMCM (MicMac) ; tandis que des traitements statistiques ont été nécessaires pour supprimer les erreurs systématiques présentes dans les nuages de points obtenus au TLS avant de les fusionner pour générer le MNTTLS. La comparaison des MNT avec des points de contrôle (GCP) positionnés au récepteur GNSS (Global Navigation Satellite System) en mode RTK (Real Time Kinematic) a montré que le MNTTLS est le plus exact avec un RMSE (Root Mean Square Error) de 4,5 cm, suivi par le MNTMCM et le MNTPSC avec des RMSE valant respectivement 9,0 et 13,9 cm. Dans un second temps, la méthode de Monte Carlo a été utilisée pour générer à partir du MNTTLS, des MNT équiprobables. L’extraction des axes de ruissellement à partir des MNT équiprobables a permis de définir pour chaque maille du MNT, la probabilité d’appartenir à l’axe de ruissellement, et de définir une zone contenant l’axe de ruissellement extrait du MNTTLS avec une probabilité définie. Une telle zone peut être utilisée pour la mise en place de solutions telles que les bandes et les chenaux enherbés. La comparaison des algorithmes de suppressions des dépressions fermées d’une part, et des algorithmes d’extraction de la direction de l’eau d’autre part, a montré peu de différence au niveau de la probabilité d’appartenance des mailles à l’axe de ruissellement lorsque le MNT est de haute résolution spatiale (± 1 m). Enfin, les analyses statistiques ont montré que les altitudes des GCP utilisés dans la méthode de Monte Carlo sont influencées par l’état d’ameublissement et par la rugosité des sols des parcelles agricoles. Les études futures, e.g., à l’échelle de la Wallonie, devront prendre en compte l’impact de ces erreurs. [less ▲]

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See detailStandardization of DiaSorin and Roche automated third generation PTH assays with an international standard: impact on clinical populations
CAVALIER, Etienne ULg; DELANAYE, Pierre ULg; LUKAS, Pierre ULg et al

in Clinical Chemistry & Laboratory Medicine (2014), 52(8), 1137-41

Background: Standardization of parathyroid hormone (PTH) assays is a major issue, especially in hemodialyzed (HD) patients. Two automated third generation PTH assays (Roche Elecsys and DiaSorin Liaison ... [more ▼]

Background: Standardization of parathyroid hormone (PTH) assays is a major issue, especially in hemodialyzed (HD) patients. Two automated third generation PTH assays (Roche Elecsys and DiaSorin Liaison) are now available. These assays are specific for the (1-84) PTH and do not cross-react with the (7-84) fragment, contrary to second generation (intact) assays. We aimed to calibrate the two methods against the WHO International PTH Standard (IS) 95/646 to see if the two assays could provide comparable results in a population of healthy subjects, HD patients and patients suffering from primary hyperparathyroidism (PHP). Methods: We selected 79 healthy subjects and two populations of patients presenting PTH disorders: 56 HD and 27 PHP patients. We reconstituted the IS in a pool of human serum containing undetectable levels of 1-84 PTH and prepared 13 serum standards ranging from 0 to 2000 pg/mL. The standards were run on the two instruments to calibrate the assays on the IS. The different populations were run before and after restandardization. Results: As these kits were differently calibrated, the results obtained after restandarization were significantly different. Restandardization process improved concordance between assays and, taking the analytical variability of the two kits into account, the results could be considered to be similar. Conclusions: Restandardization of automated third generation PTH assays with the WHO 1-84 PTH Standard significantly reduces inter-method variability. Reference ranges and raw values are totally transposable from one method to the other in healthy subjects, but also in diseased patients, e.g., with HD or those suffering from PHP. [less ▲]

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See detailCompeting Latin American Regionalisms in a changing world
Santander, Sébastian ULg

in Telò, Mario (Ed.) European Union and New Regionalism. (2014)

Collective ambitions in Latin America (LA) go hand in hand with the processes of independence and the creation of States. Since the 19th century, the continent has experienced wave after wave of different ... [more ▼]

Collective ambitions in Latin America (LA) go hand in hand with the processes of independence and the creation of States. Since the 19th century, the continent has experienced wave after wave of different types of regionalism: the ‘Bolivarian’ joint project, ‘introverted’ regional associations and ‘open’ regionalism. LA’s ‘left-turn’ has given rise to a new wave of regional projects. Described by some as post-liberal, these projects have also seen changes. Shared ambitions have therefore continued to be at the heart of the political debate of LA decision-makers. Nonetheless, while LA regionalism is a constant over time, it is still a work-in-progress. Its nature keeps evolving, based on changes in the domestic and international political context. As a political phenomenon, regionalism covers a dynamic and shifting reality. This reality can move forward, slow down or move backwards, as this comparative analysis of LA regional organisations (ROs) shows. These changes can also be the result of competition between these projects. We will also see that, while regionalisms are the result of a political will of their own, they can also be fashioned by external actors’ strategies. The US’s penchant for bilateralism and the EU’s role as an active promoter of international regionalism all affect these collective LA projects. Thus, this paper does not just aim to study regionalism in a comparative way but also to situate it in its links with international relations (IR). The article is structured in three parts. The first aims to study the structural nature of regionalism in LA. To do so, a comparative analysis of the different regional initiatives is suggested, plus a look at the impact from outside factors and actors. This approach will also allow us to bring out the similarities and differences between the different waves of regionalism, to understand what has been achieved and the lessons learnt from old projects in order to better grasp the specificity and nature of current regional initiatives. Our last point will focus on the implications of LA and global geopolitical changes for the new regionalism in LA. [less ▲]

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See detailRegional, Interregional and Global Arrangements and Multilateral Organizations
Santander, Sébastian ULg

in Telò, Mario (Ed.) European Union and New Regionalism. Regional actors and global governance in a post-hegemonic era (2014)

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See detailImprovement of defect detection in shearography by using Principal Component Analysis
Vandenrijt, Jean-François ULg; Lièvre, Nicolas; Georges, Marc ULg

in Proceedings of Conference on Interferometry XVII: Techniques and Analysis (2014, August)

Detailed reference viewed: 16 (8 ULg)
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See detailDeveloping situational judgment tests to assess organizational citizenship behaviours
Lothe, Benoit ULg; Hansez, Isabelle ULg

Conference (2014, August)

a) Purpose As Organizational Citizenship Behaviours (OCBs) positively influence a number of important outcomes (e.g. job performance, unit productivity, organizational efficiency, etc.) and are valued by ... [more ▼]

a) Purpose As Organizational Citizenship Behaviours (OCBs) positively influence a number of important outcomes (e.g. job performance, unit productivity, organizational efficiency, etc.) and are valued by managers as well, Organ, Podsakoff and Podsakoff (2010) assert the need “to try to identify and select those job candidates who have a propensity to exhibit these behaviours” (p.314). This study provides some empirical evidence about using Situational Judgment Tests (SJTs) for this specific target and allows us to discuss the main methodological issues in the development of such SJTs. b) Method Based on relevant best practices and recommendations from the literature (e.g. Weekley, Ployhart & Holtz, 2006), two distinct SJTs were especially developed to comply with OCBs assessment. The two SJTs differ on their job specificity degree (project manager in the industrial sector vs transversal function in the services sector), both propose ten different work related situations and, for each stem, five action proposals are available. Data were collected through online survey on two different samples (220 white collars professionals and 291 university students). Professionals were allowed to choose which SJT they wanted to participate, students were randomized within the two SJTS. An experimental manipulation of the response instructions (ipsative vs normative) was added within the student sample. OCBs were concurrently collected using self-reported measurement scales. c) Results In both samples (respectively professionals and students), the internal consistency was higher for the “job specific” SJT (α = .79 & .81) than for the “transversal job” SJT (α = .49 & 64). Notwithstanding, significant relations were found between the SJT scores and overall OCB ratings for both of the SJT forms in each of the two samples (r ranged from .30 to .57). Other specifics findings also provided substantial evidence for the concurrent validity of the SJTs to measure sub-dimensions of OCBs (altruism, courtesy, civic virtue, sportsmanship, loyalty and voice). d) Conclusions This study is, to our knowledge, the first to address the development and validation of a SJT for the assessment of OCBs. Review of the literature indicates that researches on techniques to predict OCBs are scarce and the present findings appear to surpass the average personality traits validity coefficients (r= .20) according to Organ & al. (2010)’s meta-analysis. There are two main practical implications. The first is the opportunity to use OCBs-SJTs as an alternative to assess applicants OCBs for job-specific or generic personnel selection issue. The second is to provide methodological development advices (e.g. the choice of response instruction) to ensure the SJT match the OCBs assessment requirement. Principal current limitations call for further research development that will be discussed: using different sources of OCBs rating, testing the incremental validity on personality tests, determining whether OCBs-SJTs are correlated with cognitive ability and establishing criterion validity with job performance. [less ▲]

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See detailNatural intrauterine infection with Schmallenberg virus in malformed newborn calves: pathology and distribution of viral RNA
Bayrou, Calixte ULg; Garigliany, Mutien-Marie ULg; Sarlet, Michaël ULg et al

in Emerging Infectious Diseases (2014), 20(8),

We comprehensively surveyed morphologic alterations in calves naturally infected in utero by Schmallenberg virus (SBV) and born deformed. SBV-specific RNA was distributed unevenly in different tissues ... [more ▼]

We comprehensively surveyed morphologic alterations in calves naturally infected in utero by Schmallenberg virus (SBV) and born deformed. SBV-specific RNA was distributed unevenly in different tissues. Implications for diagnosic procedures are highlighted. [less ▲]

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See detailDiplomacia pública, ¿de la teoría a la práctica?: El caso de la Unión Europea en Brasil
Azpíroz Manero, María Luisa ULg

Conference (2014, August)

El entusiasmo académico por la diplomacia pública no se refleja en una atención específica a la misma en las estrategias de política exterior de la Unión Europea (UE). Sin embargo, su presencia se revela ... [more ▼]

El entusiasmo académico por la diplomacia pública no se refleja en una atención específica a la misma en las estrategias de política exterior de la Unión Europea (UE). Sin embargo, su presencia se revela en múltiples iniciativas en las que los agentes no gubernamentales tienen un papel clave como receptores o actores: actividades de cooperación, de intercambio, informativas. La diplomacia pública es una actividad diplomática y de comunicación política internacional que busca influenciar a públicos extranjeros con el fin de contribuir al logro de objetivos de política exterior y/o generar una imagen positiva. Funciona como una herramienta efectiva para movilizar recursos de poder blando, un poder basado en la atracción y la persuasión que se produce de modo indirecto cuando los actores políticos movilizan recursos como la cultura, los valores, las instituciones y las estrategias de política exterior. Pese a la crisis económica, la UE conserva un gran potencial de poder blando. Por eso, y dada la relevancia de Brasil como socio prioritario en la región latinoamericana, este artículo investiga qué diplomacia pública ha desarrollado la UE en este país los últimos tres años, así como su correspondencia con el cuerpo teórico sobre esta actividad. [less ▲]

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See detailUnderstanding of the diversity of earthquake turbiditic flows in a single lake: the case of the Lake Hazar on the East Anatolian Fault
Lamair, Laura ULg; Hage, Sophie ULg; Hubert, Aurelia ULg et al

Poster (2014, August)

The East Anatolian Fault (EAF) is a major left-lateral strike-slip fault accommodating with the conjugate North Anatolian Fault the westward extrusion of the Anatolian Plate away from the Arabia-Eurasia ... [more ▼]

The East Anatolian Fault (EAF) is a major left-lateral strike-slip fault accommodating with the conjugate North Anatolian Fault the westward extrusion of the Anatolian Plate away from the Arabia-Eurasia collision zone. The East Anatolian Fault ruptured over most of its length during the 19th century in a series of magnitude ~7 earthquakes. During the 20th century this fault was less active with only two events of magnitude greater than 6. This absence of large earthquakes has resulted in relatively little attention being paid to the East Anatolian Fault compared to the North Anatolian Fault, which has ruptured during the last century in several earthquakes of Ms~7. To constrain the seismic history of the East Anatolian Fault in its central part, we focus on the Hazar Lake, occupying a 20 km long pull-apart basin. Short cores and long sedimentary cores were collected at three different sites to retrieve a paleoseismic record. Small correlative coarse-grained sedimentary events are identified in all cores. The age of the events is inferred combining radiocarbon and radionuclide (137 Cs and 210Pb) dating. We present here detailed analyses of three sedimentary events assigned respectively to the historical earthquakes occurring in 1789, 1513-1514, 1285. The source of the sedimentary events is different at the three sites. We combine X-ray imagery, magnetic susceptibility, grain-size and XRF measurements with thin section analysis to investigate the nature of sedimentary events. The analyses show first that the three sedimentary events are different. The magnitude of the terrigenous signal varies significantly. Second the correlative events have a different expression at the three sites. So each site has a different and specific sensitivity. In particular, an individual event can be composed of several coarse-grained sub-events of different magnitude with a time lapse in between greater than a week. The latter is reveals by the presence of bioturbation in particular by chironomids in individual thin sand layers. Thin section also shows that subevents are gradded. Each coarse-grained layer is thus a separated turbiditic flow. The site with the highest sensitivity is the one located near the near-shore steep submarine southern slopes overhanged by the steep subaerial slopes of the Hazar Mountains. The rivers draining the Hazar Mountains are ephemeral and provide a restricted sedimentary supply. In addition, seismic reflection data show that the submarine slopes do not to accumulate a significant sedimentary load. However on these steep slopes, an earthquake intensity of 6 or less is enough to trigger a slope failure and the associated turbiditic flow. We conclude that the different sub-events at this site may record a complete earthquake sequence, i.e the main-shock and its foreshocks and aftershocks. [less ▲]

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See detailHARBIYE AQUEDUCT: A RECORD OF PAST EARTHQUAKES
Lamair, Laura ULg; Degée, Hervé ULg; Hubert, Aurelia ULg et al

Poster (2014, August)

This paper presents a detailed analysis of Harbiye aqueduct (Hatay, Turkey). The region is situated at the junction of two major faults (East Anatolian fault and the Dead Sea fault) and is well known for ... [more ▼]

This paper presents a detailed analysis of Harbiye aqueduct (Hatay, Turkey). The region is situated at the junction of two major faults (East Anatolian fault and the Dead Sea fault) and is well known for his important historic seismicity. The aqueduct is located close to Antioch on the Orontes (known as Antakya). The city was founded in the third century BC. Harbiye aqueduct is characterized by different stages of building (Benjelloun et al., submitted). A phase is dated to Caligula period. After the 37 AD earthquake, the aqueduct was rebuilt. We noticed the presence of two dissociated travertine and a changing of masonry material. We also observed several damages and repair structures dating from Roman time. We assume that our observations are the results of one or more earthquakes. Since the construction of the aqueduct, historical seismic records mention 13 earthquakes that provoked severe damages in the city of Antioch (Guidoboni et al. 1994, Al-Tarazi, 1999, Över et al. 2002). The last one occurred in 1872 (M=7.2). In order to test our hypothesis, we modelled the structure of the aqueduct by using FineLg, a software developed at University of Liege. The seismic signals were chosen in the European Strong-motion database (Ambraseys et al., 2002) according the following criteria: a bedrock station (to avoid site effect), a strike-slip fault mechanism and a distance between the station and the epicenter around 20-30 km. The aqueduct is located at about 25 km of the Dead Sea Fault. We tested several magnitudes for the purpose of estimate the magnitude of the earthquake(s) which destroy(s) the studied aqueduct. Our results highlight the bond between the magnitude, the damage and the weakness area of this type of structure. [less ▲]

Detailed reference viewed: 13 (0 ULg)