References of "Lebeau, Frédéric"
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See detailDéveloppements scientifiques et nouvelles technologies pour l'application de produits phytosanitaires de précision
Lebeau, Frédéric ULg

Conference (2017, March 10)

Depuis leur introduction, les produits phytosanitaires ont largement démontré leur efficacité pour assurer des rendements agricoles élevés. Toutefois, les nuisances sanitaires et environnementales sont ... [more ▼]

Depuis leur introduction, les produits phytosanitaires ont largement démontré leur efficacité pour assurer des rendements agricoles élevés. Toutefois, les nuisances sanitaires et environnementales sont rapidement apparues ainsi que le développement de diverses résistances. Les développements scientifiques récents, qui permettent une meilleure compréhension du processus d’application tant pour les chercheurs que les agriculteurs, ouvrent la porte à de nombreux développements technologiques. Une présentation des principales bases physiques du processus permet d’éclaircir les diverses options technologiques à la disposition des agriculteurs pour améliorer leurs pratiques en traitement des cultures. En particulier, l’attention est portée sur la trajectoire des gouttes entre la buse et sa cible ainsi que la rétention du produit par les plantes. Ces considérations se traduisent par diverses options technologiques au niveau des agro-équipements et produits de traitement qui doivent être prises en considération pour effectuer les investissements les plus pertinents et choisir les meilleures options lors du traitement. [less ▲]

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See detailThermal Conductivity of Straw Bales: Full Size Measurements Considering the Direction of the Heat Flow
Costes, Jean-Philippe; Evrard, Arnaud; Biot, Benjamin et al

in Buildings (2017), 7(11), 1-15

The thermal conductivity of straw bales is an intensively discussed topic in the international straw bale community. Straw bales are, by nature, highly heterogeneous and porous. They can have a relatively ... [more ▼]

The thermal conductivity of straw bales is an intensively discussed topic in the international straw bale community. Straw bales are, by nature, highly heterogeneous and porous. They can have a relatively large range of density and the baling process can influence the way the fibres are organised within the bale. In addition, straw bales have a larger thickness than most of the insulating materials that can be found in the building industry. Measurement apparatus is usually not designed for such thicknesses, and most of the thermal conductivity values that can be found in the literature are defined based on samples in which the straw bales are resized. During this operation, the orientation of the fibres and the density may not be preserved. This paper starts with a literature review of straw bale thermal conductivity measurements and presents a measuring campaign performed with a specific Guarded Hot Plate, designed to measure samples up to 50 cm thick. The influence of the density is discussed thoroughly. Representative values are proposed for a large range of straw bales to support straw-bale development in the building industry. [less ▲]

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See detailMeasurements of reference ISO nozzles by high-speed imaging
De Cock, Nicolas ULg; Massinon, Mathieu ULg; Nuyttens, David et al

in Crop Protection (2016), 89

Agricultural spray characteristics determine the efficiency of a pesticide application because size and velocity affect droplet trajectory and impact behavior. At present, the relevance of different ... [more ▼]

Agricultural spray characteristics determine the efficiency of a pesticide application because size and velocity affect droplet trajectory and impact behavior. At present, the relevance of different characterization techniques remains controversial since discrepancies may be significant between measurements performed in different laboratories. A digital image acquisition technique and analysis algorithm is proposed for droplet size and velocimetry measurements as an alternative to well-established techniques such as the Phase Doppler Particle Analyzer (PDPA) or laser diffraction spectrometry (LDS). The algorithm requires double exposed shadow images acquired in a back-lighted arrangement with a Particle Image Velocimetry (PIV) camera and a pulsed light emitting diode (LED). Spatial illumination heterogeneities are corrected by subtracting from each image a mean background acquired on several images without any particle. The algorithm accuracy is ensured by the rejection of out-of-focus particles using a focus parameter depending on gradient intensity at the particle edges. Thresholds for focus particle selection were determined by studying the evolution of the focus parameter and the error on particle size measurements from images containing droplets with uniform size at various distance of the object plane. Selected droplets were identified on both pairs of images to determine their size and velocity. Droplet size distributions were corrected to account for the uneven sampling probability caused by the volumetric method. Droplet size distributions of a set of reference nozzle/pressure combinations defined in the ISO/DIS 25358 were measured. The image technique was able to distinguish each of the reference sprays well. Comparison with PDPA measurements showed that the imaging technique tends to measure an equivalent Dv50, a lower Dv10 and a higher Dv90 leading therefore to a higher relative span factor. Velocity measurements showed good agreement between both techniques except for one nozzle/pressure combination. [less ▲]

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See detailPredicting the dynamic impact behaviour of spray droplets on flat plant surfaces
Delele, Mulugeta Admasu; Nuyttens, David; Douga, Ashenafitilahun T. et al

in Soft Matter (2016), 12 (34)(7), 195-211

The dynamic impact behaviour of water droplets on plant surfaces was investigated based on a multiphase computational fluid dynamics (CFD) model. The study was conducted using the Volume Of Fluid (VOF ... [more ▼]

The dynamic impact behaviour of water droplets on plant surfaces was investigated based on a multiphase computational fluid dynamics (CFD) model. The study was conducted using the Volume Of Fluid (VOF) approach. The static contact angle of water droplets on leaf surfaces of different plants (apple, pear, leek and cabbage) was measured and found to vary between 54.9 and 138.2°. Impact experiments were conducted by monitoring the flow and impact characteristics of water droplets on leaves in still air with a high speed camera. Droplets were generated by an agricultural flat fan spray nozzle moving across the leaf at constant speed. The nozzle produced droplets with diameters ranging from 20.6 up to 550.8 μm, and droplet velocity values near the impact between 0.03 and 13.2 m s(-1). The CFD model was capable of predicting the observed dynamic impact behaviour of droplets on the plant surfaces. The fate of the droplets after the impact process for adhesion, bouncing or splashing was accurately predicted for Weber numbers (We) in the range of 0.007 to 1096 and droplet Reynolds numbers (Re) between 5 to 8000. The process was highly dependent on the surface and droplet flow characteristics during the impact. Combinations of We, Re and Ohnesorge (Oh) numbers defined the droplet maximum spread factor, the number of secondary droplets generated as a result of the splashing process and the transition between the different impact outcomes. These criteria can then be used in field scale spray deposition and drift models to better understand agricultural spray operations. [less ▲]

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See detailDynamics of a thin radial liquid flow
De Cock, Nicolas ULg; Massinon, Mathieu ULg; Ouled Taleb Salah, Sofiene ULg et al

in Fire Safety Journal (2016), 83

The present work proposes an extension of the existing analytical development on the radial spread of a liquid jet over a horizontal surface to the case of a thin radial flow. When the gap, H, between the ... [more ▼]

The present work proposes an extension of the existing analytical development on the radial spread of a liquid jet over a horizontal surface to the case of a thin radial flow. When the gap, H, between the jet nozzle and the plate is reduced the discharging area may be smaller than the inlet area leading to an increase of the main flow velocity downstream of the thin cylindrical opening. This increase of velocity, de fined here as 1/alpha , can be related to the relative gap of the nozzle H/R with R the nozzle pipe radius. Numerical computations with a volume of fluid method were realised with for H/R ranging from 0.2 to 3 and with flow rates Q of 3 and 6 l/min1. The results of these computations allowed to express alpha in respect of H/R. Taking in account the flow acceleration allowed to extend the set of equation from the jet impacting flow to the thin cylindrical opening flow. The liquid layer thickness and the surface velocity diff er with a maximum error of 4% between the flow predicted by the model and computations. Main discrepancies appear in the region close to the nozzle where the analytical model assumption of a constant velocity outside the boundary layer is not valid. However, further downstream the model and the computations are in good agreement. [less ▲]

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See detailA review on the use of sensors to monitor cattle jaw movements and behavior when grazing
Andriamandroso, Andriamasinoro ULg; Bindelle, Jérôme ULg; Mercatoris, Benoît ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment (2016), 20

Precision Livestock Farming (PLF) is spreading rapidly in intensive cattle farms. It is based on the monitoring of individuals using different kinds of sensors. Applied to grazing animals, PLF is mainly ... [more ▼]

Precision Livestock Farming (PLF) is spreading rapidly in intensive cattle farms. It is based on the monitoring of individuals using different kinds of sensors. Applied to grazing animals, PLF is mainly based on the recording of three parameters: the location, the posture and the movements of the animal. Until now, several techniques have been used to discriminate grazing and ruminating behaviors with accuracies over 90% on average, when compared to observations, providing valuable tools to improve the management of pasture and grazing animals. However, bites and jaw movements are still overlooked, even though they are of utmost importance to assess the animal grazing strategies for various pasture types and develop future techniques allowing better estimation of their intake. The goal of this review is to explore the possibility of monitoring the individual jaw movements and the differentiation of bites in grazing animals. For this purpose, (1) the mechanisms of forage intake in cattle are explained briefly in order to understand the movements performed by the cow, especially during grazing, (2) the various sensors that have been proposed to monitor jaw movements of ruminants such as mechanical sensors (pressure sensors), acoustic sensors (microphone) and electromyography sensors are compared and (3) finally the relationship between jaw movements, biting behavior and forage intake is discussed. The review clearly demonstrated the abilities of mechanical, acoustic and electromyography sensors to classify the difference types of jaw movements. However, it also indicated a wide range of accuracies and different observation windows required to reach these accuracies when compared to the observed movement. This classification purpose could lead to a better detection of more specific behavior, e.g. bite detection, and their exact location on pasture. [less ▲]

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See detailMeasuring spore settling velocity for an improved assessment of dispersal rates in mosses
Zanatta, Florian ULg; Vanderpoorten, Alain ULg; Patiño, Jairo et al

in Annals of Botany (2016)

The settling velocity of diaspores is a key parameter for the measurement of dispersal ability in wind-dispersed plants and one of the most relevant parameters in explicit dispersal models, but remains ... [more ▼]

The settling velocity of diaspores is a key parameter for the measurement of dispersal ability in wind-dispersed plants and one of the most relevant parameters in explicit dispersal models, but remains largely undocumented in bryophytes. The settling velocities of moss spores were measured and it was determined whether settling velocities can be derived from spore diameter using Stokes’ Law or if specific traits of spore ornamentation cause departures from theoretical expectations. [less ▲]

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See detailLINKING CATTLE GRAZING BEHAVIOR TO METHANE AND CARBON DIOXIDE DYNAMICS
Blaise, Yannick ULg; Lebeau, Frédéric ULg; Andriamandroso, Andriamasinoro ULg et al

in Communications in Agricultural and Applied Biological Sciences (2016, February), 81(1), 107-112

Various methods are presently used to measure methane (CH4) emissions of ruminants on pasture. Those measurements are essential to evaluate nutritional strategies to mitigate enteric CH4 emissions as well ... [more ▼]

Various methods are presently used to measure methane (CH4) emissions of ruminants on pasture. Those measurements are essential to evaluate nutritional strategies to mitigate enteric CH4 emissions as well as addressing the selection of low producing individuals. On pasture and in the barn, variations in CH4 emissions are observed depending on the time of the day. However, no studies have been made to link these diurnal fluctuations to behavioural phases, especially on pasture. The aim of this study was to understand the individual dynamics of CH4 production and their links to the grazing behaviour. For this purpose, a new tool was specifically developed. Five red-pied dry cows were equipped with infrared CH4 and carbon dioxide (CO2) sensors measuring concentrations in the exhaled air at 4 Hz. The animals were equipped with a heart rate belt (HR) and motion sensors to detect their feeding behaviours (grazing vs. rumination) for periods of 8 h/d. Wind speed (WS) was also monitor to verify interference with sampled gas concentrations. Results showed that using the CH4:CO2 ratio reduced the interference with WS that was observed on raw CH4 and CO2 concentration signals. CH4:CO2 ratio average over 5 min periods indicated that CH4 emissions were lower during grazing than rumination (P<0.01). The eructation frequency during grazing (0.48 eructation/min, P<0.01) was also lower than during rumination (0.65 eructation/min). HR was higher during grazing that rumination. Because HR is usually linked to metabolic CO2 production intensity, hence influencing the denominator of the CH4:CO2 ratio, further investigation should focus on the quantification of changes in fermentative and metabolic CO2 emissions along the day to estimate total CH4 production more accurately and the relationship between CH4 emissions patterns and post-feeding times. [less ▲]

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See detailOUTDOOR MEASUREMENT OF CATTLE METHANE EMISSIONS USING THE EDDY-COVARIANCE TECHNIQUE IN COMBINATION WITH GEOLOCALIZATION DEVICES
Dumortier, Pierre ULg; Andriamandroso, Andriamasinoro ULg; Aubinet, Marc ULg et al

Poster (2016, February)

Methane emissions account for 8% of the EU-15 GHG emissions and livestock generates approximately half of these emissions [1]. In order to improve emissions reporting and properly test mitigation options ... [more ▼]

Methane emissions account for 8% of the EU-15 GHG emissions and livestock generates approximately half of these emissions [1]. In order to improve emissions reporting and properly test mitigation options, techniques for measuring methane emissions from cattle must be developed and adapted to each management system. Among available micrometeorological methods, the use of eddy-covariance is still in its infancy [2] and its relevance and robustness for cattle flux estimation has still to be proved. On one hand, it is well adapted to seasonal grazing systems, is non-invasive, needs little animal handling and allows detection of daily emission patterns. On the other hand, it has the drawback of requiring cattle geo-localization and long periods of measurements (typically one month). In this study, we combined measured CH4 fluxes with a footprint model [3] and cattle positions (GPS devices) over several one-month campaigns at key periods in the grazing season in order to obtain CH4 emissions per cow at herd scale. Accelerometers were also added to the system for behaviour detection, opening the possibility of linking emissions to feeding behaviour. Measurements were performed and are still ongoing at the Dorinne Terrestrial Observatory in 2014/2015. The first campaign provided a mean emission per cow of 65±6 kg CH4.LSU-1.year-1. Cattle emission pattern was tightly linked with behaviour pattern, emissions being higher during and shortly after grazing (i.e. at dawn and dusk). Uncertainties linked to the method will be discussed and quantified (footprint model validity, geo-localization precision, eddy covariance corrections and filtering specificities linked to CH4 measurements). Compilation of data from multiple campaigns will allow quantification of the effects of forage quality, animal weight and lactating state on emissions per cow. [less ▲]

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See detailStudying the impact characteristics of spray droplets on plant surfaces using a multiphase CFD model
Delele, Mulugeta Admasu; Nuyttens, David; Ambaw, A et al

in Balsari, P; Cooper, S E; Glass, C R (Eds.) et al International Advances in Pesticide Application (2016, January)

The impact characteristics of spray droplets on plant surfaces was investigated based on a multiphase computational fluid dynamics (CFD) model using the Volume Of Fluid (VOF) approach. The contact angle ... [more ▼]

The impact characteristics of spray droplets on plant surfaces was investigated based on a multiphase computational fluid dynamics (CFD) model using the Volume Of Fluid (VOF) approach. The contact angle of the droplet on different surfaces was measured and included as a model parameter. The model was validated using experimental results that were conducted on different plant surfaces (apple, pear, cabbage and leek) and the model was applied to study the effect of droplet impact velocity, droplet diameter, formulation and surface topology on droplet impact characteristics. For each combination of model parameters, the model was capable of predicting the droplet impact outcome (adherence, rebound, splash and shattering). The results showed that multiphase CFD model has a capacity to predict the behavior of plant protection mixture droplets at impact on target surfaces. [less ▲]

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See detailReduced span spray – Part 1: Retention
Massinon, Mathieu ULg; De Cock, Nicolas ULg; Ouled Taleb Salah, Sofiene ULg et al

in Aspect of Applied Biology, International Advances in Pesticide Application (2016, January)

Maximising treatment efficiency for a given target lies mainly on depositing a maximum part of the spray volume within an optimal droplet size range, which has to be as narrow as possible to reduce ... [more ▼]

Maximising treatment efficiency for a given target lies mainly on depositing a maximum part of the spray volume within an optimal droplet size range, which has to be as narrow as possible to reduce retention variability and drift issues. The present work focuses on exploring the effect of span factor of the droplet size distribution on the final retention by a 3D target plant using a modelling approach with the final aim of guiding the development of a reduced span nozzle (Reduced span spray – Part 3: Design of narrow span nozzle). Five droplet size spans have been tested for three VMD and three wetting scenarios on the same 3D plant architecture. Performing a screening of the different parameters involved in spray retention with a modelling approach based on a deeper understanding of leaf/droplet interactions is a valuable approach for highlighting the optimal droplet size distribution maximising droplet retention for a given target/formulation combination. [less ▲]

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See detailReduced span spray: Part 3: Design of a narrow span nozzle
De Cock, Nicolas ULg; Massinon, Mathieu ULg; Ouled Taleb Salah, Sofiene ULg et al

in Aspect of Applied Biology (2016, January)

Optimisation of the droplet spectra of the agricultural spray may increase the spray application efficiency. The optimal spray would contain only the most efficient droplets in term of speed and size ... [more ▼]

Optimisation of the droplet spectra of the agricultural spray may increase the spray application efficiency. The optimal spray would contain only the most efficient droplets in term of speed and size. Therefore, this paper is presenting the first steps of the design of a narrow span nozzle in order to produce an optimised spray. The starting geometry is a splash plate nozzle with a disk ending with structures (i.e. tooth, grooves, and needles) that would separate the liquid sheet into jets. These jets would be in the Rayleigh regime which has the advantage of producing narrower droplet spectra than liquid sheet break-up. The present project aims to design a hydraulic nozzle producing a spray with a narrow drop size distribution in order to increase the agricultural spray application efficiency. In the present paper the first project steps are presented. [less ▲]

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See detailLa paille parois performantes - Vademecum 2
de Herde, André; Evrard, Arnaud; Rouche, Sylvie et al

Book published by UCL (2016)

En novembre 2011, un consortium rassemblant l’Université catholique de Louvain (Architecture et Climat), l’Université de Liège (GeMMe et UMC), l’Institut de Conseil et d’Études en Développement Durable ... [more ▼]

En novembre 2011, un consortium rassemblant l’Université catholique de Louvain (Architecture et Climat), l’Université de Liège (GeMMe et UMC), l’Institut de Conseil et d’Études en Développement Durable (ICEDD) et la jeune entreprise Paille-Tech est formé autour du projet de recherche « aPROpaille » » financé par la DGO4 (Direction générale opérationnelle de l’Aménagement du territoire, du Logement, du Patrimoine et de l’Énergie) dans le cadre du programme ERable, organisé par le Service Public de Wallonie (DGO4 et DGO6, Direction Générale Opérationnelle de l’Économie, de l’Emploi et de la Recherche). Ce projet très complet a permis de déterminer les caractéristiques et performances des matériaux « terre » et « paille », de réaliser des simulations de comportement hygrothermique des parois en paille, de les comparer à des monitorings de bâtiments existants en paille, de réaliser une analyse de cycle de vie (ACV) de ce type de paroi… Outre la réalisation d’une plateforme Internet (www.apropaille.be) sur la filière belge, les principaux résultats de cette recherche ont été rassemblés fin 2015 dans trois vadémécums à destination d’un public large et varié. Ces vadémécums, dont le présent document en est la deuxième partie, ont pour but d’offrir à tout un chacun une information rigoureuse, claire et compréhensible, des avancées récentes de ce domaine pour favoriser le développement de la filière de la paille utilisée comme matériau isolant dans la construction. Afin de permettre aux acteurs du monde de la construction de s’approprier les connaissances relatives à ce matériau, ce vadémécum s’intéressera aux parois que les ballots de paille permettent de réaliser et à leurs performances. C’est le vadémécum le plus technique. Il commence par l’analyse microscopique des brins de paille pour ensuite décrire l’ensemble de propriétés hygrothermiques des ballots et des enduits en terre qui leur sont souvent associés. Une attention particulière est donnée à l’analyse de la conductivité thermique des ballots de paille. Un troisième chapitre analyse le comportement hygrothermique dynamique de différentes parois en paille et identifier les points clefs de leur performances en terme d’isolation, d’inertie thermique, de régulation de l’humidité et de leur validité à longs termes. Le quatrième chapitre aborde ces thématiques, mais du point de vue du confort des occupants, de l’évolution de l’ambiance intérieure et des consommations d’énergie. Le cinquième chapitre détaille l’analyse du résultat des trois monitorings effectués dans le cadre de la recherche. Le sixième chapitre présente un ensemble de noeuds constructifs et donne la valeur à utiliser pour le calcul des ponts thermiques. Le septième chapitre présente l’analyse du cycle de vie réalisée dans le cadre de la recherche en identifiant l’influence de différents scénarios. Le dernier chapitre fait une brève analyse économique de différents systèmes constructifs. [less ▲]

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See detailLa paille matière première - Vadémécum 1
de herde, André; Evrard, Arnaud; Rouche, Sylvie et al

Book published by UCL (2016)

En novembre 2011, un consortium rassemblant l’Université catholique de Louvain (Architecture et Climat), l’Université de Liège (GeMMe et UMC), l’Institut de Conseil et d’Études en Développement Durable ... [more ▼]

En novembre 2011, un consortium rassemblant l’Université catholique de Louvain (Architecture et Climat), l’Université de Liège (GeMMe et UMC), l’Institut de Conseil et d’Études en Développement Durable (ICEDD) et la jeune entreprise Paille-Tech est formé autour du projet de recherche « aPROpaille » » financé par la DGO4 (Direction générale opérationnelle de l’Aménagement du territoire, du Logement, du Patrimoine et de l’Énergie) dans le cadre du programme ERable, organisé par le Service Public de Wallonie (DGO4 et DGO6, Direction Générale Opérationnelle de l’Économie, de l’Emploi et de la Recherche). Ce projet très complet a permis de déterminer les caractéristiques et performances des matériaux « terre » et « paille », de réaliser des simulations de comportement hygrothermique des parois en paille, de les comparer à des monitorings de bâtiments existants en paille, de réaliser une analyse de cycle de vie (ACV) de ce type de paroi… Outre la réalisation d’une plateforme Internet (www.apropaille.be) sur la filière belge, les principaux résultats de cette recherche ont été rassemblés fin 2015 dans trois vadémécums à destination d’un large et varié. Ces vadémécums, dont le présent document en est la première partie, ont pour but d’offrir à tout un chacun une information rigoureuse, claire et compréhensible, des avancées récentes de ce domaine pour favoriser le développement de la filière de la paille utilisée comme matériau isolant dans la construction. Afin de permettre aux acteurs du monde de la construction de s’approprier les connaissances relatives à ce matériau, ce vadémécum s’intéressera au ballot de paille en tant que matière première. D’où vient le ballot de paille ? Comment est-il produit ? Quelles sont les dimensions disponibles ? Comment identifier la céréale à la base du ballot de paille ? Comment obtenir un ballot de qualité pour la construction ? La paille est-elle une ressource inépuisable ? ... A la lecture de ces quelques pages, le lecteur sera invité à découvrir le ballot de paille en tant que produit agricole avant qu’il ne devienne un matériau de construction. [less ▲]

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See detailHigh rate monitoring CH4 production dynamics and their link with behavioral phases in cattle
Blaise, Yannick ULg; Lebeau, Frédéric ULg; Andriamandroso, Andriamasinoro ULg et al

in EAAP – 67 th Annual Meeting, Belfast 2016 (2016)

Microbial fermentation in the rumen produces methane (CH4) which is a loss of energy for ruminants and also contributes to global warming. While the respiration chamber is the standard reference for CH4 ... [more ▼]

Microbial fermentation in the rumen produces methane (CH4) which is a loss of energy for ruminants and also contributes to global warming. While the respiration chamber is the standard reference for CH4 emissions quantification, daily CH4 production dynamics can be measured only by steps of 30 min and measurements on pasture are impossible. The alternative method using SF6 as tracer gas can be applied for grazing animals but provides average CH4 production values over at least several hours, making it impossible to measure short term dynamics of rumen CH4 production with changing animal behavior along the day. Newly developed methods using CO2 as internal tracer gas extrapolate CH4 emissions from few short measurements. However, both CO2 and CH4 emissions fluctuate during the day depending on the behavior and the post-feeding times questioning the validity of this method. Therefore, an innovative device was developed to monitor at a high rate CH4 and CO2 emission dynamics in order to investigate the link between CH4 dynamics and the animal behavior on pasture. Preliminary results showed the ability of the device to record differences in CH4:CO2 ratios and eructation frequencies according to the individual and the behavior. Results from complementary experiments in barn with animals fed contrasting diets regarding CH4 production (with and without linseed) and on pasture with different forage allowance will be presented in order to highlight how post-feeding time and grazing behavior impact CO2 and CH4 emission dynamics along the day. [less ▲]

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See detailLa paille - projets construits
de Herde, André; Evrard, Arnaud; Rouche, Sylvie et al

Book published by UCL (2016)

En novembre 2011, un consortium rassemblant l’Université catholique de Louvain (Architecture et Climat), l’Université de Liège (GeMMe et UMC), l’Institut de Conseil et d’Études en Développement Durable ... [more ▼]

En novembre 2011, un consortium rassemblant l’Université catholique de Louvain (Architecture et Climat), l’Université de Liège (GeMMe et UMC), l’Institut de Conseil et d’Études en Développement Durable (ICEDD) et la jeune entreprise Paille-Tech est formé autour du projet de recherche « aPROpaille » financé par la DGO4 (Direction générale opérationnelle de l’Aménagement du territoire, du Logement, du Patrimoine et de l’Énergie) dans le cadre du programme ERable, organisé par le Service Public de Wallonie (DGO4 et DGO6, Direction Générale Opérationnelle de l’Économie, de l’Emploi et de la Recherche). Ce projet très complet a permis de déterminer les caractéristiques et performances des matériaux « terre » et « paille », de réaliser des simulations de comportement hygrothermique des parois en paille, de les comparer à des monitorings de bâtiments existants en paille, de réaliser une analyse de cycle de vie (ACV) de ce type de paroi… Outre la réalisation d’une plateforme Internet (www.apropaille.be) sur la filière belge, les principaux résultats de cette recherche ont été rassemblés fin 2015 dans trois vadémécums à destination d’un public large et varié. Ces vadémécums, dont le présent document en est la troisième partie, ont pour but d’offrir à tout un chacun une information rigoureuse, claire et compréhensible, des avancées récentes de ce domaine pour favoriser le développement de la filière de la paille utilisée comme matériau isolant dans la construction. Afin de permettre aux acteurs du monde de la construction de s’approprier les connaissances relatives à ce matériau, ce vadémécum s’intéressera aux projets qu’il est possible de construire et montre que les possibilités architecturales que permet l’utilisation de ce type de matériaux sont multiples et sont à la hauteur de la créativité des concepteurs qui les font naître. Le premier chapitre retrace synthétiquement l’historique de ce type de construction. Le deuxième définit une série de modes constructifs fréquemment rencontrés dans la pratique sur base du rôle constructif que joue la paille dans les parois. Une série de fiches est alors présentée pour constituer un catalogue de projets qui sont repris sur la plateforme Internet. Certains projets, les « cas d’étude », sont plus détaillés et leurs fiches reprennent l’ensemble des documents graphiques utiles pour comprendre leur plans, coupes et façades. Un dernier chapitre, intitulé « FAQs », tente de répondre aux questions les plus fréquemment posées sur la construction en paille. [less ▲]

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See detailÉtude des potentialités des systèmes d’application contrôlée des gouttes (CDA) pour les traitements phytosanitaires en céréaliculture (synthèse bibliographique)
Ouled Taleb Salah, Sofiene ULg; De Cock, Nicolas ULg; Massinon, Mathieu ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment (2016)

Introduction. L’application contrôlée des gouttes (CDA) présente le double avantage de réduire à la fois l’étendue de la distribution des tailles des gouttes et le volume appliqué par rapport aux buses ... [more ▼]

Introduction. L’application contrôlée des gouttes (CDA) présente le double avantage de réduire à la fois l’étendue de la distribution des tailles des gouttes et le volume appliqué par rapport aux buses hydrauliques conventionnelles. Littérature. Cette revue investigue la potentialité de la CDA par rapport aux buses hydrauliques dans le cadre du désherbage précoce des adventices (2-3 feuilles). En termes de rétention, les études reliant les caractéristiques des gouttes (taille, vitesse et direction) et l’architecture, la densité et la mouillabilité du feuillage, en fonction de la formulation de bouillies, ont été abordées. Ces études montrent que des gouttes de 300 μm avec un adjuvant approprié et des jets émis 60° vers l’avant par rapport à la verticale contribuent à l’augmentation de la rétention sur les cibles problématiques à port dressé. L’effet des réductions des volumes d’application pour ces deux techniques est étudié sur base de la moyenne, du coefficient de variation et du taux de couverture des dépôts. Néanmoins, les résultats de ces études ne peuvent être généralisés du fait des différences de réglages opératoires entre les deux techniques d’application. Quant à la dérive, les atomiseurs CDA orientés horizontalement présentent un potentiel de dérive plus important que les buses hydrauliques pour lesquelles le spray est orienté vers le bas. La dérive augmente avec la vitesse du vent et diminue lorsque le diamètre médian volumétrique (DV50) augmente. Conclusions. De nouveaux réglages des atomiseurs de la CDA en termes de DV50 et de direction du jet peuvent répondre aux défis de l’agriculture de précision. Les pistes d’innovations proposées sont d’une part une amélioration de la résistance à l’usure des dents situées en bordure des disques et, d’autre part, une distribution granulométrique plus étroite. [less ▲]

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See detailTemperature and moisture storage in crop-based materials: Modelling a straw bale wall subject to a thermal shock
Dubois, Samuel ULg; Evrard, Arnaud ULg; Blecker, Christophe ULg et al

in Jounal of Building Physics (2016)

Modelling the hygrothermal behaviour of crop-based insulation products is essential to assess their impact on the energy performance of the building, predict indoor climate conditions, and prevent any ... [more ▼]

Modelling the hygrothermal behaviour of crop-based insulation products is essential to assess their impact on the energy performance of the building, predict indoor climate conditions, and prevent any risk of unexpected degradation. Traditionally, transient numerical models that predict internal conditions of construction materials consider that the variation of moisture storage with temperature is negligible although the sorp- tion behaviour is known to be temperature dependent. This paper investigates this par- ticular effect for crop-based materials and uses a refinement of standard mathematical representations. For this purpose, the effects of a thermal shock on the evolution of hygrothermal conditions inside a straw-bale wall are studied with several versions of a flexible research model. The latter is capable of incorporating the temperature depen- dency of the sorption curve with both a physically-based and an empirical description. A large climate chamber is used to gather experimental data and is able to host a full- size straw bale prefabricated panel. Internal conditions of straw bales are obtained with proper sensors bars. Results show that when large temperature gradients occur in a crop-based material, a model that considers temperature effect on moisture storage enhances greatly the prediction of internal conditions. [less ▲]

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