46 research outputs found

    Exploring the adoption of precision agricultural technologies: a cross regional study of EU farmers

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    Precision agricultural technologies (PATs) allow more detailed management of in-field variability. Policy and advisory communities have championed PATs as a route to preserving natural capital whilst increasing productivity from agricultural land. A range of PATs are currently available for the agricultural producer but uptake varies by the type of technology and region. Whereas most studies on uptake have focused on US or Australia we empirically examine uptake of machine guidance (MG) and variable rate nitrogen technologies (VRNT) within European farming systems. Using primary information from 971 arable crop growers across five countries: Belgium, Germany, Greece, the Netherlands and the UK, a multilevel random intercept regression estimated a) the differences between adoption and non-adoption and b) the differences between VRNT and MG adoption. We find, aside from size and income differences, which reflect the economic cost barrier to adoption, an attitudinal difference, in terms of optimism towards the technology's economic return leading to more probability of uptake. Moreover innovative and information seeking behaviour also proved significant when upgrading from machine guidance to variable rate technologies. Subsidy and taxation were considered positive drivers of uptake within the community. However, results suggest that more indirect interventions, such as informational support to counteract industry bias, and demonstration to prove the viability of economic return may be effective at meeting land manager and policy expectations towards PATs

    Study of CCD mosaic configurations for the ILMT: Astrometry and photometry of point sources in the absence of a TDI corrector

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    The image deformations induced by the time-delay integration (TDI) mode, used with a CCD camera at the prime focus of a Liquid Mirror Telescope (LMT), can be corrected for by a system of lenses, simultaneously with the optical aberrations. However, before adopting the design of a TDI corrector, we may wonder what is the importance of the TDI image deformations and how to possibly reduce these by choosing optimal mosaic configurations of CCDs, covering an equivalent field of view. In a first step, we have simulated the point spread function (PSF) deformation due to the TDI mode only, for different selected mosaic configurations. We have then estimated the importance of the astrometric and photometric errors induced by the TDI deformation. By simulating star fields with the same synthetic PSF and taking into account realistic sources of noise (cf. CCD readout noise, photon noise and sky background), we have derived the limiting magnitudes for photometry and astrometry for the case of a 4 m LMT

    Self-assembly of poly(ethylene oxide)-b-poly(e-caprolactone) copolymers in aqueous solution

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    The associative behavior of monodisperse diblock copolymers consisting of a hydrophilic poly(ethylene oxide) block and a hydrophobic poly(epsilon-caprolactone) or poly(gamma-methyl-epsilon-caprolactone) block has been studied in aqueous solution. Copolymers have been directly dissolved in water. The solution properties have been studied by surface tension, in relation to mesoscopic analyses by NMR (self-diffusion coefficients), transmission electron microscopy, and small-angle neutron and X-ray scattering. The experimental results suggest that micellization occurs at low concentration (approximately 0.002 wt %) and results in a mixture of unimers and spherical micelles that exchange slowly. The radius of the micelles has been measured (ca. 11 nm), and the micellar substructure has been extracted from the fitting of the SANS data with two analytical models. The core radius and the aggregation number change with the hydrophobic block length according to scaling laws as reported in the scientific literature. The poly(ethylene oxide) blocks are in a moderately extended conformation in the corona, which corresponds to about 25% of the completely extended chain. No significant modification is observed when poly(gamma-methyl-epsilon-caprolactone) replaces poly(epsilon-caprolactone) in the diblocks

    Development of a sensor for continuous soil resistance measurement

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    In this investigation, some possible methods to measure soil resistance on-the-go were examined. All of them used the measurement of the horizontal force needed to penetrate soil. Two systems were built and tested. The first one used horizontally mounted classic penetrometers, while the second one measured the bending moment on wings which were pulled through the soil at a fixed angle. From tests performed in a soil bin and in the field, it can be concluded that both systems gave good results. Also (poor) correlation between vertical and horizontal forces was demonstrated. Both methods, but especially the second, have potential, but further investigation is needed before the system can be used reliably in field mapping for precision agriculture

    Multi-phase cross-correlation method for motion estimation of fertiliser granules during centrifugal spreading

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    International audienceExcessive fertiliser use has been a main contributor to the increasing environmental imbalance observed in the past 20 years. Better accuracy in spreading would limit excess fertiliser loss into the environment. Increased accuracy begins by understanding the fertiliser spreading process from the vane to the soil. Our work concentrates on the use of centrifugal spreaders, as these are most commonly used in Europe. Progress in imaging devices and image processing has resulted in the availability of new technologies to use when describing the behaviour of fertiliser granules during ejection from centrifugal spreaders. Fertiliser deposition on the soil can be predicted using a ballistic flight model, but this requires determination of the velocities and the directions of the granules when they leave the spinning disc. This paper presents improvements to the high speed imaging system that we had previously developed, i.e. enhancements to the illumination and the image processing. The illumination of the previous system, which used many separate flashes, did not give consistent illumination. We have improved it by using a stroboscope with power-LEDs, located at 1 m height around the digital camera and controlled by a Field-programmable gate array (FPGA) card. The image processing has been improved by development of a multi-phase method based on a cross-correlation algorithm. We have compared the cross-correlation method to the Markov Random Fields (MRF) method previously implemented. These tests, based on multi-exposure images, revealed that cross-correlation method gives more accurate results than the MRF technique, with guaranteed sub-pixel accuracy. Knowing that an error of one pixel can lead to a prediction error between 200 and 500 mm on the ground, the latter method gives an accuracy range between 0.1 and 0.4 pixels, whereas the MRFs technique is limited to 3 and 9 pixels for the vertical and horizontal components of the velocities, respectively. The sub-pixel accuracy of the new method was proven by applying it on simulated images with known displacements between the grains. By using a realistic spreading model, the simulated images are similar to those obtained with a high speed imaging system. This sub-pixel accuracy now makes it possible to decrease the resolution of the camera to that of a classical high-speed camera. These improvements have created an affordable and durable system appropriate for installation on a spreader. Farmers could use this system to both calibrate the spreader and verify the fertiliser distribution on the ground
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