References of "Lebeau, Frédéric"
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See detailApplications de la terre crue en construction
Grigoletto, Sophie ULg; Paul, Julien; Lebeau, Frédéric ULg et al

Conference (2015, November 05)

L’utilisation de l’argile en construction permet d’atteindre des propriétés spécifiques en termes de résistance mécanique et d’inertie thermique. Les recherches menées à l’Université de Liège, en ... [more ▼]

L’utilisation de l’argile en construction permet d’atteindre des propriétés spécifiques en termes de résistance mécanique et d’inertie thermique. Les recherches menées à l’Université de Liège, en collaboration avec l’entreprise MOBIC, ont permis de développer des produits permettant l’amélioration de l’inertie thermique de panneaux à ossature bois. L’effet de l’apport de la couche d’inertie au sein des constructions à ossature bois a été quantifié expérimentalement par l’instrumentation de modules jumeaux de 20m². Cet effet sur le confort thermique a également été modélisé par des simulations thermiques en vue de quantifier les bénéfices sur les surchauffes en été, les réductions des consommations énergétiques en hiver pour divers scénarii au moyen d’un programme de simulation dynamique des échanges thermiques et des bilans d’énergie au sein de bâtiments [less ▲]

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See detailStraw-bale walls for sustainable architecture: Improving and promoting straw-bale use in European Buildings
Evrard, Arnaud; Biot, Benjamin; Keutgen, Gauthier et al

in Cucinella; Giulia (Eds.) Architecture in (R)Evolution (2015, September 09)

Straw-bale use in buildings may be an interesting way to decrease our energy needs and our impact on the environment. Moreover, it fosters a local economy and the creation of new jobs in the building ... [more ▼]

Straw-bale use in buildings may be an interesting way to decrease our energy needs and our impact on the environment. Moreover, it fosters a local economy and the creation of new jobs in the building industry. Combined with earth materials and other well-selected materials and systems, it allows creative designers to integrate highly efficient, low-tech and reusable envelopes in comfortable and healthy places. The present paper summarizes the results of a four year R&D program aiming to improve and promote the use of straw bale in buildings and also to remove uncertainties concerning this use. Three main aspects are pinpointed and discussed: hygrothermal transfer and storage in straw-bale walls, regulation of indoor conditions and environmental impact in the long term. These three topics were submitted to European experts (France, England and Germany) in order to discuss a cross-comparison of results obtained on a larger scale. The paper shows that straw-bale use in buildings is a relevant and innovative solution in facing one of the major challenges of today and tomorrow: "How to build/transform comfortable and affordable buildings with local resources and with a positive impact on the environment?". [less ▲]

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See detailChanges in biting characteristics recorded using the inertial measurement unit of a smartphone reflect differences in sward attributes
Andriamandroso, Andriamasinoro ULg; Lebeau, Frédéric ULg; Bindelle, Jérôme ULg

in Guarino, Marcella; Berckmans, Daniel (Eds.) Precision Livestock Farming '15 (2015, September)

Accurate monitoring of grazing activity at individual cow level would provide useful information to farmers to improve the management of their animals and pastures in intensive dairy systems. Pasture ... [more ▼]

Accurate monitoring of grazing activity at individual cow level would provide useful information to farmers to improve the management of their animals and pastures in intensive dairy systems. Pasture attributes, starting with sward height, influence grazing behaviour and bites characteristics. In an attempt to link sward height to an individual automated detection of biting behaviour, a series of recording sessions of 4×3 days were realized on a ryegrass pasture with two contrasting heights (5 and 15 cm) over the grazing season (from July to October) with 4 dry red-pied cows equipped with the inertial measurement unit (IMU) of a smartphone on a halter, recording acceleration data at 100Hz. The behaviours were video-recorded. The number of grazing bouts performed during grazing trends to increase when the grass is highest. Fourier transforms of acceleration data showed that grazing bouts were characterized by a distinctive acceleration peak which frequency ranged between 1.02Hz and 1.46Hz whatever the sward height. It corresponded to the uprooting of grass frequency in the biting movement when compared with the observation in the video recordings and it could be used to improve automated grazing behaviour detection and to remotely characterize bites. These results show that some bite characteristics are influenced by sward height and automated individual monitoring of grazing behaviour is possible. An extension of this methodology should allow analysing more deeply the grazing behaviour of cattle in order to determine number of bites and possibly to link it to biomass intake. [less ▲]

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See detailSpray retention variaility by barley
Boukhalfa, Hassina dite Hafida ULg; Lebeau, Frédéric ULg

Conference (2015, May 19)

The effectiveness of a phytosanitary treatment depends on the amount of product actually retained by the plant leaves relative to the volume per hectare applied. Parameters affecting spray retention ... [more ▼]

The effectiveness of a phytosanitary treatment depends on the amount of product actually retained by the plant leaves relative to the volume per hectare applied. Parameters affecting spray retention include application variables such as nozzle type, operating pressure and formulation, and target properties such as species and growth stage. These variables condition more specific parameters such as the number of droplet impacts by unit area of leaf, the droplet size and velocity distributions at impact, droplet physicochemical properties (dynamic surface tension and viscosity) for the application variables and leaf wettability and plant architecture for the target. During a uniform treatment of the crop, each plant receives various droplet distributions that behave differently during impact depending on its architecture. In consequence, this contributes to increase the varying retentions observed between plants in field trials, leading in practice to apply an amount of product always greater than required to provide the level of crop protection needed for insuring high yields. The aim of this paper is to observe the retention variability that can occur during a treatment depending on the equipment, tank mix formulation and crop properties. The spray retention variability was assessed for three tank mix formulations: tap water, tap water with break thru, and tap water with Li700. For each formulation ten sprays were realized on five barley plants at the two leaves growth stage (BBCH stage 12) grown indoor in controlled conditions and ten sprays realized on individual barley plants at the same growth stage. The amount of spray actually retained by barley plants was assessed by dosing a fluorescent tracer added to the mixtures. Barley plants were placed linearly below the center of a moving nozzle at the speed of 2m/s using a pressure of 2 bars. The last step was measuring leaf area for each spray and calculating the amount of sprays retained by barley plants to determine the variability of spray retention. [less ▲]

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See detailDrop size distribution measurement of ISO nozzles by shadowgraphy method
De Cock, Nicolas ULg; Massinon, Mathieu ULg; Ouled Taleb Salah, Sofiene ULg et al

in Drop size distribution measurement of ISO nozzles by shadowgraphy method (2015, May 19)

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See detailDrift potential of tilted shielded rotary atomisers based on wind tunnel measurements
Ouled Taleb Salah, Sofiene ULg; Massinon, Mathieu ULg; De Cock, Nicolas ULg et al

in 67th International Symposium on Crop Protection (2015, May 19)

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See detailComputer simulations of spray retention by a 3D barley plant: effect of formulation surface tension
Massinon, Mathieu ULg; De Cock, Nicolas ULg; Ouled Taleb Salah, Sofiene ULg et al

in 67th International Symposium on Crop Protection (2015, May 19)

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See detailStudy of retention variability on an early growth stage herbaceous plant using a 3D virtual spraying model
Massinon, Mathieu ULg; Dumont, Benjamin ULg; De Cock, Nicolas ULg et al

in Crop Protection (2015), 78

A model predicting the spray droplet interception and retention by a single virtual plant has been developed. The model was based on three main experimental inputs: the 3D architecture of a barley plant ... [more ▼]

A model predicting the spray droplet interception and retention by a single virtual plant has been developed. The model was based on three main experimental inputs: the 3D architecture of a barley plant, the spray quality and the droplet impact behavior. Two contrasted formulation scenarios, limits of the common range covered by pesticide application in terms of surface tension, were tested by changing the droplet behavior at impact in the model. Simulations were undertaken for studying the variability of spray retention resulting from spray quality, applied volume and plant size for a difficult-to-treat target. Results showed that the spray retention efficiency ranged from 6.8% to 96.6% of a theoretical full adhesion scenario, where all intercepted droplets were captured, according to spray quality for the two formulation scenarios tested. Average retention increased with increasing spray fineness, applied volume per hectare and plant size. Variability of deposits, evaluated using the coefficient of variation of simulated retentions, was found to be a function of the mean droplet density according to CV∝N^(-0.68), where CV is the coefficient of variation and N the number of droplet per square centimeter. Variability was also found to be a function of the plant size according to a relation CV∝S^(-0.5), where S is the total leaf area of the plant model. The variability of deposits increased with decreasing spray fineness, applied volume per hectare and plant size because of the reduced number of droplets contributing to retention. Wetting properties greatly influenced retention but surprisingly poorly influenced the variability of deposits. Such a modeling approach that is capable of an independent investigation of the influence of various parameters on spray retention can be used to improve understanding of application methods and adjuvants that could help minimizing development of resistance in problematic weed species. [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 (2015)

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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See detailFirst monitoring results of three straw bale buildings in Belgium
Evrard, Arnaud; Dubois, Samuel ULg; Louis, Arnaud et al

Conference (2014, December 13)

Straw bale use in buildings may be an interesting way to decrease our energy needs and our impact on environment. The present paper describes an experimental set up to monitor three straw bale buildings ... [more ▼]

Straw bale use in buildings may be an interesting way to decrease our energy needs and our impact on environment. The present paper describes an experimental set up to monitor three straw bale buildings recently built in Belgium. For each building, results on temperature and relative humidity, inside and outside, are analyzed, as well as internal evolution of temperature and humidity distribution in the walls. The first building is an office building where two finishing are compared. Measurements also provide additional data on CO2 levels and electric consumption. The two other buildings are dwellings where live one single family. In the first one, a wall in the bedroom and a retaining wall are analyzed. In the second one, a wall in the bedroom and a wall in the bathroom are analyzed. Their hygrothermal behavior is discussed based on simulation results obtained with WUFI Pro and WUFI Plus software. The criterion for the validation of wall behavior is based on water content distribution through the walls. The paper confirms the great potential of this type of building technology and helps to identify how to assess and validate their effective hygrothermal behavior. [less ▲]

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See detailAn inverse modelling approach to estimate the hygric parameters of clay-based masonry during a Moisture Buffer Value test
Dubois, Samuel ULg; McGregor, Fionn; Evrard, Arnaud et al

in Building & Environment (2014), 81

This paper presents an inverse modelling approach for parameter estimation of a model dedicated to the description of moisture mass transfer in porous hygroscopic building materials. The hygric behaviour ... [more ▼]

This paper presents an inverse modelling approach for parameter estimation of a model dedicated to the description of moisture mass transfer in porous hygroscopic building materials. The hygric behaviour of unfired clay-based masonry samples is specifically studied here and the Moisture Buffer Value (MBV) protocol is proposed as a data source from which it is possible to estimate several parameters at once. Those include materials properties and experimental parameters. For this purpose, the mass of two clay samples with different compositions is continuously monitored during several consecutive humidity cycles in isothermal conditions. Independently of these dynamic experimental tests, their moisture storage and transport parameters are measured with standard steady-state methods. A simple moisture transfer model developed in COMSOL Multiphysics is used to predict the moisture uptake/release behaviour during the MBV tests. The set of model parameters values that minimizes the difference between simulated and experimental results is then automatically estimated using an inverse modelling algorithm based on Bayesian techniques. For materials properties, the optimized parameters values are compared to values that were experimentally measured in steady state. And because a precise understanding of parameters is needed to assess the confidence in the inverse modelling results, a sensitivity analysis of the model is also provided. [less ▲]

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See detailThe impact and retention of spray droplets on a horizontal hydrophobic surface
Zwertvaegher, Ingrid; Verhaeghe, Micheline; Brusselman, Eva et al

in Biosystems Engineering (2014), 126

Spray retention, i.e. the overall capture of spray droplets by plants on initial or subsequent impact, and after loss due to run-off, is an important stage in the spray application process as droplet ... [more ▼]

Spray retention, i.e. the overall capture of spray droplets by plants on initial or subsequent impact, and after loss due to run-off, is an important stage in the spray application process as droplet losses may result in reduced efficacy, economic loss, and environmental contamination. The aim of this exploratory study is to determine whether a new method based on calculating the volumetric proportions per impact type, i.e. adhesion, rebound and shatter, can be used to predict spray retention. These volumetric proportions are calculated based on logistic regression models, derived from vision-based droplet characteristics and impact assessments, and laser-based spray characteristics. The advantages and limitations of such a method are explored. The volumetric proportions per impact type on a horizontal, synthetic hydrophobic surface were determined for four different nozzles (XR 110 01 VS flat-fan nozzle, XR 110 04 VS flat-fan nozzle, XR 110 08 VS flat-fan nozzle and AI 110 08 VS air-induction nozzle) under controlled realistic conditions, and compared to the results of a retention test. The volumetric proportions of adhesion were much lower than the relative retentions, indicating that a considerable amount of rebound and shatter also contributed to final retention. The method should thus be improved by including the droplets retained after first impact and the retained proportions of partial droplet fragmentation but it is nevertheless considered a promising technique. [less ▲]

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See detailNon-isothermal moisture balance equation in porous media: a review of mathematical formulations in Building Physics
Dubois, Samuel ULg; Lebeau, Frédéric ULg; Evrard, Arnaud ULg

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2014), 18(3),

Understanding heat and mass transfers in porous materials is crucial in many areas of scientific research. Mathematical models have constantly evolved, their differences lying mainly in the choice of the ... [more ▼]

Understanding heat and mass transfers in porous materials is crucial in many areas of scientific research. Mathematical models have constantly evolved, their differences lying mainly in the choice of the driving potentials used to describe moisture flows, as well as in the complexity of characterizing the physical phenomena involved. Models developed in the field of Building Physics (HAM models) are used to describe the behavior of envelope parts and assess their impact on user comfort and energy performance. The water balance equation can be described in many ways; it is a function of the boundary conditions considered and the fact they induce high or low water content in the porous materials used. This paper gives an overview of various formulations for this equation that are found in the Building Physics literature. It focuses first on the physically based formulation of moisture balance, drawing on the Representative Elementary Volume (REV) concept, coupled with thermodynamic flow rates description. This is then reformulated in line with various main moisture state variables offering a wide variety of expressions that are compared with available models. This approach provides access to all secondary transport coefficients associated with the process of mathematical transformation. Particular emphasis is placed on the moisture storage function choice and its impact on the final mathematical formulations. [less ▲]

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See detailAccurate monitoring of the rumination behaviour of cattle using IMU signals from a mobile device
Andriamandroso, Andriamasinoro ULg; Lebeau, Frédéric ULg; Bindelle, Jérôme ULg

in Hopkins, A; Collins, RP; Fraser, MD (Eds.) et al EGF at 50: The Future of European Grasslands. Proceedings of the 25th General Meeting of the European Grassland Federation. (2014, September)

Improving the monitoring of rumination in cattle could help in assessing of the welfare status and their risk of acidosis. In this work, the monitoring of cattle’s behaviour was performed using the ... [more ▼]

Improving the monitoring of rumination in cattle could help in assessing of the welfare status and their risk of acidosis. In this work, the monitoring of cattle’s behaviour was performed using the inertial measurement unit (IMU) present in smartphones mounted on the neck of cows. The processing of both time and frequency domains of the IMU signals was capable to detect accurately the main behaviours (grazing, rumination and other) and highlight the characteristics of the rumination process. The algorithm for analysis of rumination was more accurate for grazing cattle than for silage-fed cattle in stables. [less ▲]

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See detailUse of Inertial Measurement Unit of a Mobile Device to Discriminate Cattle Grazing and Ruminating Behaviours on Pasture
Andriamandroso, Andriamasinoro ULg; Bindelle, Jérôme ULg; Lebeau, Frédéric ULg

in Animal Production in Australia (2014, September)

Precision livestock farming is emerging in the wake of the technological developments in remote sensing and motion monitoring. Tools are developed to allow accurate real time monitoring of the individual ... [more ▼]

Precision livestock farming is emerging in the wake of the technological developments in remote sensing and motion monitoring. Tools are developed to allow accurate real time monitoring of the individual cattle behaviour in a quest to improve the management of pastures. Studies have shown the relevancy of accelerometers in the analysis of behaviour using dedicated devices. Accelerometers are located either close to the mouth or jaw of the animal or on its forehead or neck. Records are usually performed at low frequency (<1Hz) and most studies classify behaviours using neuronal networks or multivariate statistical approaches, with little consideration to the animals’ actual movements. Inertial measurement units (IMU) in consumer mobile devices are specifically developed to record accurately user movements. Besides 3D-accelerometer, they can include 3-D rotational speed sensors, 3-D magnetometers and GPS. Optimised power consumption offers significant autonomy. Data directly acquired from the sensors and IMU signals from build-in proprietary algorithms can be recovered using user-friendly low-cost applications. Moreover, mobile devices can store or communicate information by wireless in real time at high frequency. As movements of cattle are in the same range as humans, this study investigates the relevancy of mobile devices IMU signals to discriminate main behaviours of cattle on pasture. [less ▲]

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See detailAnalysis of spray retention on a 3D black-grass plant model as a function of spray nozzle and formulation using a process-driven approach
Massinon, Mathieu ULg; Ouled Taleb Salah, Sofiene ULg; Dumont, Benjamin ULg et al

Poster (2014, August 13)

The efficiency of spray application of foliar plant protection products can be variable because of the different amount of spray solution intercepted and retained by leaves. On one hand, the spray ... [more ▼]

The efficiency of spray application of foliar plant protection products can be variable because of the different amount of spray solution intercepted and retained by leaves. On one hand, the spray interception by plants is affected by nozzle kind, size and operating pressure as well as by the plant architecture. On the other hand, the spray retention is affected by application parameters resulting from droplet size and velocity as well as spray mixture physicochemical properties. In this paper, spray retention is tackled with a physical approach at the droplet scale. The methodology deals with high-speed imaging to characterize droplet impacts; adhesion, rebound or shatter on small excised leaf areas and the spray granulometry. The 3D reconstruction of a black-grass plant involves a structured light technique. The overall spray retention was determined by using an interception algorithm combined with a process-driven retention approach as a function of the spray nozzle and formulation used. The interception model allowed determining the spray retention by a single plant and discriminating application parameters by explaining the variability resulting from various droplet size distributions intercepted by single plant. Such a model can be used to increase the understanding of interactions between spray techniques and plant architectures. [less ▲]

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See detailThe performance of mobile devices' inertial measurement unit for the detection of cattle's behaviors on pasture
Andriamandroso, Andriamasinoro ULg; Dumont, Benjamin ULg; Lebeau, Frédéric ULg et al

Conference (2014, July 21)

Over the past decade, the Precision Livestock Farming (PLF) concept has taken a considerable place in the development of accurate methods for a better management of farm animals, as Precision Agriculture ... [more ▼]

Over the past decade, the Precision Livestock Farming (PLF) concept has taken a considerable place in the development of accurate methods for a better management of farm animals, as Precision Agriculture has done for crop production. Mass consumption mobile devices have nowadays the possibility to record accurately user movements with their Inertial Measurement Unit (IMU). We used iPhone 4S to detect accurately cattle behaviors such as grazing and ruminating with the aim of performing a precision grazing management on the near future. Results showed accuracies ranging between 84% and 100% when detecting these two major behaviors by analyzing recorded raw signals in the time-domain. Ongoing research tries to link these behaviors to different pasture characteristics and performs a refined signal processing analysis for a better monitoring of some possible behavioral changes. [less ▲]

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See detailNumerical modelling of mirror nozzle flow
De Cock, Nicolas ULg; Massinon, Mathieu ULg; Mercatoris, Benoît ULg et al

Conference (2014, July 15)

Detailed reference viewed: 90 (39 ULg)