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See detailDevelopment of a generic aquaponic model using object oriented programming to study the systems at the individuals level
Stalport, Benoît ULiege; Raulier, Pierre ULiege; De Cock, Nicolas ULiege et al

Poster (2019, February 04)

Aquaponics is the association of fish and plant farming, exploiting the natural phenomenon observed in aquatic ecosystems. The microbiota transforms the fish waste into different chemical forms that are ... [more ▼]

Aquaponics is the association of fish and plant farming, exploiting the natural phenomenon observed in aquatic ecosystems. The microbiota transforms the fish waste into different chemical forms that are less toxic for fish and very suited for hydroponic plants culture. Due to its recent and quick development, aquaponics can now be found in a variety of areas of interest such as personal installations, education fields, private and public research projects and reached nowadays the food production at medium and large scales industries. The diversity found in these installations makes it difficult to identify the mechanisms that rule aquaponics and to generalize the findings to other systems. Few researches established the equations that govern the behaviour of one particular system, in order to estimate the productions and to apply sensitivity analysis. These models often satisfy the goals of the developers but cannot be applied to different system setups. In this context, a generalist model is being developed for aquaponics. The equations are based on aquaculture, hydroponics and aquaponics researches and are implemented using an object-oriented programming in order to generate a completely generic model. The European Smart Aquaponics Project provides numerous systems with different architectures. All these installations are equipped with a full set of aquaponics sensors to generate a strong aquaponic database that will be used for model development. The computed outputs are various and new ones are regularly added to keep pace with the continuous development of aquaponics. In this case study, the model has been applied to an experimental setup to illustrate the basic calculated parameters such as the dynamical behaviours of the water volumes and several nutrient concentrations, the vegetal and animal biomasses, the water consumption, a few economic criteria, etc. [less ▲]

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See detailMécanismes de dépôts et d’impacts de gouttes de pulvérisation
Lebeau, Frédéric ULiege; De Cock, Nicolas ULiege

in Colloque sur les techniques d'application des produits de protection des plantes (2018, March 14)

Le développement d’un modèle complet de l’application des produits de protection des plantes est une tâche complexe d’intégration des connaissances existantes et d’identification des questions ... [more ▼]

Le développement d’un modèle complet de l’application des produits de protection des plantes est une tâche complexe d’intégration des connaissances existantes et d’identification des questions scientifiques en suspens. Une approche multi-échelles de modélisation qui combine la physique sous-jacente à l’échelle de la goutte avec les échelles agronomiques et environnementales apparait judicieuse en vue de mieux guider les industriels dans leurs développements, le législateur dans ses choix réglementaires et les agriculteurs dans l’exécution de leurs traitements. La rupture des veines fluides et nappes liquides, le transport aérien au-dessus de la parcelle, le transport et l’interception par les plantes au sein de la canopée soulèvent encore des questionnements. La rétention a profité des développements théoriques qui clarifient le sort des gouttes lors de l’impact. L’intégration de l’ensemble de ces connaissances vise à mieux évaluer les impacts des choix technologiques sur l’efficacité des traitements et sur l’environnement. [less ▲]

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See detailDesign of a narrow span nozzle: a round jet impacting a disk engraved with radial grooves
Ouled Taleb Salah, Sofiene ULiege; De Cock, Nicolas ULiege; Massinon, Mathieu et al

in Ouled Taleb Salah, Sofiene (Ed.) Aspects of Applied Biology 137, International Advances in Pesticide Application (2018, January)

The present work investigates the impact of a turbulent round jet on a motionless disk that is engraved along its circumference by a number N of radial grooves. The grooves are used to split the liquid ... [more ▼]

The present work investigates the impact of a turbulent round jet on a motionless disk that is engraved along its circumference by a number N of radial grooves. The grooves are used to split the liquid sheet into multiple jets. According to the incoming flow and to the geometry of the grooves, the number of the generated jets n correspond to: 2 N jets, N* jets (mixed zone), N jets and N/2 jets. The emitted droplets sizes are characterized. [less ▲]

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See detailExperimental investigation of a round jet impacting a disk engraved with radial grooves
Ouled Taleb Salah, Sofiene ULiege; Duchesne, Alexis ULiege; De Cock, Nicolas ULiege et al

in European Journal of Mechanics. B, Fluids (2018), 72

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See detailDesign of a hydraulic nozzle with a narrow droplet size distribution
De Cock, Nicolas ULiege

Doctoral thesis (2017)

Nowadays, pesticides use is necessary to satisfy the growing demand for agricultural products. During pesticide spray application, the agricultural mixture containing the active ingredient is fragmented ... [more ▼]

Nowadays, pesticides use is necessary to satisfy the growing demand for agricultural products. During pesticide spray application, the agricultural mixture containing the active ingredient is fragmented to a cloud of droplets of various sizes and speeds. The droplet size distribution within the spray affects the efficiency of the treatment. According to the target, a specific droplet size should be used. However, hydraulic nozzles usually used in field application produce sprays with a wide droplet size distribution containing an important proportion of small or too large droplets. This results in non-optimal application and therefore losses of product into the environment. This statement conducted the research as early as in the 60’s to create the rotary atomizer. This device is able to produce narrow droplet size distribution using Plateau-Rayleigh break up mechanism. The characteristics of the produced spray by the rotary atomiser can be tuned by adjusting the rotational speed and the volumetric flow rate. Although offering agronomic and environmental qualities this has not met success for the application of plant protection products in field crops because of their cost, size and complexity. The aim of the thesis was the design of a hydraulic nozzle with the rotary atomizer qualities and without the constraints of rotating parts. Unlike the rotary atomizer which has two control variables, the developed hydraulic nozzle will have a narrower operating range, thus a specific geometry has to be design for each kind of treatment. The new hydraulic nozzle design is composed by an inlet pipe ending perpendiculary on a plate. There is a thin opening at the junction between the pipe and the plate. The edge of the plate is constituted of channels formed by structures. These channels aim to divide the liquid sheet in multiple jets. The breakup of these jets into droplets generate a narrow droplet size distribution. The thesis can been seen as a roadmap providing design tools at each step starting from the determination of an optimal droplet size according to the kind of treatment and ending with a nozzle geometry. The prediction of the optimal droplet size according to the treatment was done using integrated modelling approach of the spray transport and retention by the plant. As each spray requires a specific nozzle geometry, an analytical model of the flow on the nozzle was developed. This model allows the determination of geometry according to the desired spray. Finally, a prototype of nozzle has been built. The measurement of the spray characteristics of the prototype was realized using a developed high-speed imaging technique providing the droplet size and speed. The prototype showed results in term of narrowing of the droplet size distribution. [less ▲]

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See detailInvestigation on optimal spray properties for ground based agricultural applications using deposition and retention models
De Cock, Nicolas ULiege; Massinon, Mathieu ULiege; Ouled Taleb Salah, Sofiene ULiege et al

in Biosystems Engineering (2017), 162

In crop protection, it is well known that droplet size determine spray efficacy. The optimisation of both spray deposition and retention leads to a dilemma: should small droplets be used to increase ... [more ▼]

In crop protection, it is well known that droplet size determine spray efficacy. The optimisation of both spray deposition and retention leads to a dilemma: should small droplets be used to increase retention or large droplets be preferred to avoid drift? An ideal droplet should have a short time of flight to minimise its distance travelled while impacting the target with a moderate kinetic energy. This paper aims to determine an optimum range of droplet sizes for boom-sprayer applying herbicide using a modelling approach. The main parameters of spray deposition and retention models are systematically varied and the effects on drift potential and droplet impaction outcomes are discussed. The results of the numerical simulations showed that droplets with diameter ranging between 200 μm and 250 μm offer high control of deposition by combining a low drift potential and a moderate kinetic energy at top of the canopy. A fourfold reduction of the volume drifting further than 2 m from the nozzle was observed for a spray with a volume median diameter of 225 μm when the relative span factor of the droplet spectrum was reduced from 1.0 to 0.6. In the latter scenario, an increase from 63 to 67% of the volumetric proportion of droplets adhering to the wheat leaf was observed. Therefore, strategies for controlling the droplet size distribution may offer promising solutions for reducing adverse impact of spray applications on environment. [less ▲]

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See detailCaméras 3D et plantes numériques : vers une automatisation de l’agriculture
Bouvry, Arnaud ULiege; Stalport, Benoît ULiege; De Cock, Nicolas ULiege et al

Diverse speeche and writing (2017)

En cours de développement à la Faculté de Gembloux Agro-Bio Tech, l’exploitation d’images en 3 dimensions de plantes permet de récolter une grande quantité de données. Cette technique, couplée à un ... [more ▼]

En cours de développement à la Faculté de Gembloux Agro-Bio Tech, l’exploitation d’images en 3 dimensions de plantes permet de récolter une grande quantité de données. Cette technique, couplée à un système mathématique de modélisation de plantes, utilisé notamment par Pixar, offre de nombreuses possibilités pour la recherche scientifique. [less ▲]

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See detailSpray droplet impaction outcomes for different plant species and spray formulations
Massinon, Mathieu ULiege; De Cock, Nicolas ULiege; Forster, W. Alison et al

in Crop Protection (2017), 99

A track-sprayer combined with a high-speed camera were used to visualize and identify droplet impaction outcomes for three formulations (water, 0.1% LI 700® (lecithin, a mixture of soya oils, propionic ... [more ▼]

A track-sprayer combined with a high-speed camera were used to visualize and identify droplet impaction outcomes for three formulations (water, 0.1% LI 700® (lecithin, a mixture of soya oils, propionic acid and surfactants) in water and 0.1% Pulse® (non-ionic surfactant, trisiloxane ethoxylate) in water) on four plant species (bean (Vicia faba L.), avocado (Persea americana L.), barnyard grass (Echinochloa crus-galli L. P. Beauv.) and cabbage (Brassica oleracea L.)) selected to represent a wide range of leaf surface characters. Droplet sizes and velocities were measured by image analysis and a multiple hypothesis tracking algorithm. Impaction outcomes were categorized into adhesion, bounce, or shatter. The probability of each outcome was estimated from logistic regression models related to the dimensionless Weber number. This approach is in contrast to various deterministic threshold criteria for droplet bounce or shatter that have been used to model droplet impaction events on leaves. It also provides a simple visual and numerical presentation of the complexity of impaction processes, and the relative influence of leaf surface character versus formulation for droplets with different impaction energies. [less ▲]

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See detailMeasurements of reference ISO nozzles by high-speed imaging
De Cock, Nicolas ULiege; Massinon, Mathieu ULiege; 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 detailDesign of an agricultural nozzle: Experimental investigation of a round jet impacting vertically a horizontal disk
Ouled Taleb Salah, Sofiene ULiege; De Cock, Nicolas ULiege; Duchesne, Alexis et al

Poster (2016, September)

This study is the first step to optimize a design of a hydraulic nozzle producing a narrow droplet spectrum based on the Rayleigh-Plateau break up mode.

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See detailDynamics of a thin radial liquid flow
De Cock, Nicolas ULiege; Massinon, Mathieu ULiege; Ouled Taleb Salah, Sofiene ULiege 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 detailReduced span spray – Part 2: Drift
Ouled Taleb Salah, Sofiene ULiege; De Cock, Nicolas ULiege; Massinon, Mathieu ULiege et al

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

Treatment efficiency is drastically affected by the amount of spray drift away the target area. The present study investigates the effect of a reduced span on spray drift based on wind tunnel measurements ... [more ▼]

Treatment efficiency is drastically affected by the amount of spray drift away the target area. The present study investigates the effect of a reduced span on spray drift based on wind tunnel measurements with the final aim of guiding the design of a reduced span nozzle (Reduced span spray – Part 3: Design of narrow span nozzle). A capillary jet with a free and a forced break up regimes, corresponding to 0.5 and 0.06 span values respectively, was tested under 2 m/s downwind speed. Droplets spots from the free break up regime show a bimodal distribution, which are related to droplets sizes: Bigger droplet travel less distance than smaller droplets. Droplet diameters measured on ground level at different distances from the generator were corroborated with the observed droplets spots. However, deposits from forced break up regime were similar to deposits obtained by the free break up regime, what may be due to emerged drops throughout the droplet stream. Much focus on the forced break up regime is needed to relate droplet size to spray drift. [less ▲]

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See detailReduced span spray – Part 1: Retention
Massinon, Mathieu ULiege; De Cock, Nicolas ULiege; Ouled Taleb Salah, Sofiene ULiege 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 ULiege; Massinon, Mathieu ULiege; Ouled Taleb Salah, Sofiene ULiege 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 detailÉtude des potentialités des systèmes d’application contrôlée des gouttes (CDA) pour les traitements phytosanitaires en céréaliculture (synthèse bibliographique)
Ouled Taleb Salah, Sofiene ULiege; De Cock, Nicolas ULiege; Massinon, Mathieu ULiege et al

in Biotechnologie, Agronomie, Société et Environnement (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 detailDrop size distribution measurement of ISO nozzles by shadowgraphy method
De Cock, Nicolas ULiege; Massinon, Mathieu ULiege; Ouled Taleb Salah, Sofiene ULiege et al

in Drop size distribution measurement of ISO nozzles by shadowgraphy method (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 ULiege; De Cock, Nicolas ULiege; Ouled Taleb Salah, Sofiene ULiege et al

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

Detailed reference viewed: 49 (23 ULiège)