Effect of tank mixed adjuvants on the drift potential of phenmedipham formulations.

in Communications in agricultural and applied biological sciences (2005), 70(4), 979-987

Modelling The Dynamic Distribution Of Spray Deposits

in Biosystems Engineering (2004), 89(3),

A mathematical model to estimate the spray distribution of phytopharmaceutical deposits under a spray boom is proposed. It focuses on the need to take account of the dynamic effects of the forward ... [more ▼]

A mathematical model to estimate the spray distribution of phytopharmaceutical deposits under a spray boom is proposed. It focuses on the need to take account of the dynamic effects of the forward movement of the boom. These are related both to the horizontal and vertical boom movement and to the influence of aerodynamic factors on the nozzle spray distribution. The distribution of the spray deposits is computed by multiplying the nozzle spray pattern by the time needed to move from one position to the next. Mathematically, this is expressed by a convolution of the trajectory function with the nozzle spray pattern function. The model is validated through a dynamic test bench to reproduce the boom movements observed in the field. The chosen method to measure the distribution of the spray deposits is a chemical dosage of the sprayed potassium chloride (KCl) solution collected in Petri dishes. A pulse-width modulation (PWM) nozzle body fitted on the test bench is used to generate a dynamic distribution of spray deposits from which the dynamic two-dimensional nozzle spray pattern is reconstructed. This dynamic nozzle spray pattern introduced in the model allows a far better estimation of the spray deposit distribution to be made than the one obtained using the static nozzle spray pattern which was computed using filtered back-projection. [less ▲]

Modélisation de la répartition dynamique des produits phytopharmaceutiques sous une rame de pulvérisation

Doctoral thesis (2003)

A mathematical model aimed at estimating the distribution of spray deposits of phytopharmaceutical <br />products under a spray boom is proposed. It focuses on the need to take account of the dynamic ... [more ▼]

A mathematical model aimed at estimating the distribution of spray deposits of phytopharmaceutical <br />products under a spray boom is proposed. It focuses on the need to take account of the dynamic effects of <br />the forward movement of the boom. These are related both to the horizontal and vertical boom <br />movement and to the influence of aerodynamical factors on the nozzle spray distribution. <br />The model allows one to compute the spray deposits distribution by multiplying the nozzle spray <br />distribution by the time needed to move from one position to the next. Mathematically, this is expressed <br />by a convolution of the trajectory with the nozzle spray distribution. <br />The model is validated through a dynamic test bench aimed at reproducing the boom movements <br />observed in the field. The chosen method to measure spray deposits distribution is a chemical dosage of <br />the sprayed KCL solution collected in Petri dishes. This method is accurate if the spacing between <br />collectors is small enough. With constant speed and height, the longitudinal variability approaches 5 % <br />and the transversal spray deposits distribution is a function of the nozzle characteristics (as measured on <br />the static spray patternator) and of the nozzle speed. <br />A Pulse Width Modulation (PWM) nozzle boss fitted on the test bench is used to generate a dynamic <br />spray deposits distribution from which the dynamic bidimensional nozzle spray pattern is reconstructed. <br />This dynamic nozzle spray pattern introduced in the model allows a far better estimation of the spray <br />deposits distribution to be made than the one obtained using the static nozzle spray pattern computed <br />using filtered back-projection. <br />The use of the model for estimating the spray deposits distribution under a crop sprayer allows one <br />to identify the influential parameters and to calculate the dosages according to specific local <br />circumstances. Statistical parameters aimed at characterising the treatment quality are proposed. [less ▲]

On-line soil mechanical resistance mapping and correlation with soil physical properties for precision agriculture

in Soil & Tillage Research (2002), 64

Measurement of local soil strength may be used for real time regulation of tillage parameters in precision agriculture. Cartography of soil physical properties will also facilitate the study of their ... [more ▼]

Measurement of local soil strength may be used for real time regulation of tillage parameters in precision agriculture. Cartography of soil physical properties will also facilitate the study of their influence on plant development and yields. The aim of this research was to develop and test in field conditions a sensor measuring on-line soil strength variations. The sensor was constituted of a thin blade pulled in the soil at constant depth and speed and a beam which transferred the soil–blade forces to a transducer fixed on the machine. This transducer measured the draft force (Fx), the vertical force (Fz) and the moment (My). A field experiment was performed in 2 ha field of silt soil (Hesbaye, Belgium). A soil strength map of the field was established by pulling the sensor at 5 m interline separation by a tractor equipped with a DGPS receiver. The relationship between the recorded forces and several soil physical parameters was studied by identifying 10 control plots on the sensor track. In each of them, cone index penetrometry profiles and soil water content were measured. Soil samples were taken in the centre of the plots to determine cohesion and internal friction angle, simple compression resistance, Atterberg limits, granulometry and pF curves. Triaxial tests identified over-consolidated soils in plots situated in the pounds of the field. Based on the parameters measured in the other plots, significant relationships were established between (1) a global penetrometry index and the Fx and My solicitations measured by the sensor; (2) gravimetric water content and the vertical force Fz. Interpolation by inverse distance with a range of 45 m gave the best result for the cartography of the three measured signals (Fx, Fz and My). The confrontation of those maps with pedological and topographic maps together with the statistical relationships and the farmer’s knowledge of the field showed high consistency. The results of this experiment in field conditions are encouraging and show the promising perspective of technological innovations allowing on-line characterisation of soil physical state for precision agriculture. [less ▲]

Spray pattern simulation model for standardisation of boom behaviour tests.

in Aspects of Applied Biology (2002), (66),

Simulation models of spray pattern are required for the dynamic behaviour assessment of sprayer booms. The reasons are their ease of use and their independence regarding variable operating conditions such ... [more ▼]

Simulation models of spray pattern are required for the dynamic behaviour assessment of sprayer booms. The reasons are their ease of use and their independence regarding variable operating conditions such as liquid properties and nozzle state, which interfere with the discrimination between various dynamic behaviours properties. Although such models have been developed for many decades, no international consensus has been reached on their use in a standardised test procedure. A consensual model is tested in the scope of standardisation specific needs. It uses ISO-5682/1 spray table measurements of the static distributions to compute three 2-D distribution at three heights using a filtered back-projection algorithm. These distributions are interpolated to generate a 3-D matrix of repartition at various heights. This 3-D matrix is used as nozzle distribution description in a dynamic distribution model where the dynamic distribution is computed as a summation of the static distribution at successive positions. The model kernel was found suitable to predict the repartition under a moving boom. [less ▲]

Development of a multibody model of a sprayer

in Proceedings of AgEng (2002)

A multibody model of a sprayer boom including the suspension was developed by using ADAMS 11.0 (Mechanical Dynamics). The model was designed with the aim to describe the dynamic behaviour of different ... [more ▼]

A multibody model of a sprayer boom including the suspension was developed by using ADAMS 11.0 (Mechanical Dynamics). The model was designed with the aim to describe the dynamic behaviour of different types of booms and suspensions (double trapezium, trapezium, pendulum, …). This was obtained by creating a general model in which geometrical (dimensions) and mechanical parameters (mass and inertia, friction coefficients, stiffness and damping coefficients of the hinges, …) of the system were easily modified. A graphical interface especially designed authorised this easy modification. The validation of the model was obtained by measuring in real conditions the frame movements as solicitations and the boom movements as responses. The method was applied on a trailed sprayer equipped with a boom of 24 m and a trapezoidal suspension. Good accordance was found between measured and simulated vertical displacements. The model may decrease the development costs of suspension and boom designs. [less ▲]

Automatisation d'un banc de répartition pour buses de pulvérisation

in Cahiers Agricultures (2000)

Les bancs de répartition constituent l'élement de base permettant de tester la sensibilité de la distribution transversale des buses de pulvérisation aux différents paramètres de fonctionnement. L'article ... [more ▼]

Les bancs de répartition constituent l'élement de base permettant de tester la sensibilité de la distribution transversale des buses de pulvérisation aux différents paramètres de fonctionnement. L'article présente un banc d'essai conforme à la norme ISO 5682/1 qui permet une lecture automatisée des différentes grandeurs (pression, débit, volume recueilli). [less ▲]