1,396 research outputs found
Inspection system for in use pesticide application equiupment in Greece. First three years of application
According to Directive 2009/128/EC, all member states should have inspected all in-use Pesticide Application Equipment (PAE) by November 2016. In Greece, Law 4036/2012 embodied the provisions of this Directive into Greek legislation, but unfortunately due to various reasons, the inspections were significantly delayed. Aim of the current study is to briefly present the inspection system of in-use PAE that was developed due to the aforementioned law and then provide the statistical results of the inspections until February 2018. The progress of the last two years was significant, but a lot of work remains to make the inspection system functional and unproblematic.According to Directive 2009/128/EC, all member states should have inspected all in-use Pesticide Application Equipment (PAE) by November 2016. In Greece, Law 4036/2012 embodied the provisions of this Directive into Greek legislation, but unfortunately due to various reasons, the inspections were significantly delayed. Aim of the current study is to briefly present the inspection system of in-use PAE that was developed due to the aforementioned law and then provide the statistical results of the inspections until February 2018. The progress of the last two years was significant, but a lot of work remains to make the inspection system functional and unproblematic
Classical and quantum dynamics of a trapped ion coupled to a charged nanowire
We study theoretically the mechanical drive of a trapped ultracold ion by a charged nanowire through their mutual Coulomb interaction. We characterize the perturbation of the trapping potential for the ion by the nanowire and discuss the parameters determining the dynamics of the ion under the action of the nanooscillator. We explore the classical dynamics as well as motional quantum states of the ion which can be generated and manipulated with the resonant drive of the nanowire and the effects of anharmonicities of the ion-trap potential on the system. Our modelling indicates that unusual quantum states of the ion motion can be generated with this approach and that sympathetic cooling and quantum entanglement can be realised when both subsystems operate in the quantum regime. The present ion-mechanical hybrid system might prove interesting as a new quantum device, for quantum sensing experiments, for spectroscopy and for mass spectrometry
Intelligent dual curve-driven tool path optimization and virtual CMM inspection for sculptured surface CNC machining
This paper investigates the profitability of a dualâcurve driven surface finish tool path under the concept
of optimizing crucial machining parameters such as toroidal endâmill diameter, lead angle and tilt angle. Surface
machining error as well as tool path time are treated as optimization objectives under a multiâcriteria sense, whilst
a central composite design is conducted to obtain experimental outputs for examination and, finally, fit a full
quadratic model considered as the fitness function for process optimization by means of a genetic algorithm. A
benchmark sculptured surface given as a secondâorder parametric equation was tested and simulated using a
cuttingâedge manufacturing modeling software and best parameters recommended by the genetic algorithm were
implemented for validation. Further assessment involves the virtual inspection to selected profile sections on the
part. It was shown that the approach can produce dualâcurve driven tool trajectories capable of eliminating sharp
scallop heights, maximizing machining strip widths as well as maintaining smoothness quality and machining
efficiency
Fossil Fuel Deficit-Conservation Tillage and on Farm Biofuel Production to Cope With the Problem
Abstract The limited resources of fossil fuels along with the highly fluctuating prices, call for investigation to find diesel alternatives. Biofuels from vegetable oils, seems the easiest accessible substitutes as they can be used in conventional diesel engines without lot of modifications. There are though two mainstream attitudes on this approach. The one points that it is immoral to divert environmental resources from food production to energy production when the global population increases and the other claims that without mechanization and fuel to power it, food production will finally be decreased. Conservation tillage adoption may contribute in significant fuel savings by eliminating tillage operations. If they would be combined with on farm biofuel production, they would certainly require less land to be devoted for this purpose. In the present work, based on data of a long term tillage experiment, it was calculated the percentage of land that would be required to cultivate with a biofuel crop (sunflower for instance) in order to cover the fuel requirements of an arable farm, for three alternative tillage methods: conventional (CT), reduced (RT) and no-tillage (NT). The results indicated that in CT, the 11% of the land would be enough to provide the biofuel for all the field operations (except irrigation). In RT, due to lower fuel consumption, the 7.5% of the land would be sufficient. That means that a 3.6% yield reduction is justified. In NT, only the 3.5% of the land is required to produce the biofuels justifying a 7.7% yield reduction. This sets the limits of yield reduction that can be acceptable. However we have to add in this balance the environmental effects of using conservation tillage like erosion reduction, increasing soil organic matter and biodiversity maintenance
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Estimating Canopy Parameters Based on the Stem Position in Apple Trees Using a 2D LiDAR
Data of canopy morphology are crucial for cultivation tasks within orchards. In this study, a 2D light detection and range (LiDAR) laser scanner system was mounted on a tractor, tested on a box with known dimensions (1.81 m Ă 0.6 m Ă 0.6 m), and applied in an apple orchard to obtain the 3D structural parameters of the trees (n = 224). The analysis of a metal box which considered the height of four sides resulted in a mean absolute error (MAE) of 8.18 mm with a bias (MBE) of 2.75 mm, representing a root mean square error (RMSE) of 1.63% due to gaps in the point cloud and increased incident angle with enhanced distance between laser aperture and the object. A methodology based on a bivariate point density histogram is proposed to estimate the stem position of each tree. The cylindrical boundary was projected around the estimated stem positions to segment each individual tree. Subsequently, height, stem diameter, and volume of the segmented tree point clouds were estimated and compared with manual measurements. The estimated stem position of each tree was defined using a real time kinematic global navigation satellite system, (RTK-GNSS) resulting in an MAE and MBE of 33.7 mm and 36.5 mm, respectively. The coefficient of determination (R2) considering manual measurements and estimated data from the segmented point clouds appeared high with, respectively, R2 and RMSE of 0.87 and 5.71% for height, 0.88 and 2.23% for stem diameter, as well as 0.77 and 4.64% for canopy volume. Since a certain error for the height and volume measured manually can be assumed, the LiDAR approach provides an alternative to manual readings with the advantage of getting tree individual data of the entire orchard
Yield sensing technologies for perennial and annual horticultural crops: a review
Yield maps provide a detailed account of crop production and potential revenue of a farm. This level of details enables a range of possibilities from improving input management, conducting on-farm experimentation, or generating profitability map, thus creating value for farmers. While this technology is widely available for field crops such as maize, soybean and grain, few yield sensing systems exist for horticultural crops such as berries, field vegetable or orchards. Nevertheless, a wide range of techniques and technologies have been investigated as potential means of sensing crop yield for horticultural crops. This paper reviews yield monitoring approaches that can be divided into proximal, either direct or indirect, and remote measurement principles. It reviews remote sensing as a way to estimate and forecast yield prior to harvest. For each approach, basic principles are explained as well as examples of application in horticultural crops and success rate. The different approaches provide whether a deterministic (direct measurement of weight for instance) or an empirical (capacitance measurements correlated to weight for instance) result, which may impact transferability. The discussion also covers the level of precision required for different tasks and the trend and future perspectives. This review demonstrated the need for more commercial solutions to map yield of horticultural crops. It also showed that several approaches have demonstrated high success rate and that combining technologies may be the best way to provide enough accuracy and robustness for future commercial systems
Modeling the Link between US Inflation and Output: The Importance of the Uncertainty Channel
Analysis of lesion localisation at colonoscopy: outcomes from a multi-centre U.K. study
Background:
Colonoscopy is currently the gold standard for detection of colorectal lesions, but may be limited in anatomically localising lesions. This audit aimed to determine the accuracy of colonoscopy lesion localisation, any subsequent changes in surgical management and any potentially influencing factors.
Methods:
Patients undergoing colonoscopy prior to elective curative surgery for colorectal lesion/s were included from 8 registered U.K. sites (2012â2014). Three sets of data were recorded: patient factors (age, sex, BMI, screener vs. symptomatic, previous abdominal surgery); colonoscopy factors (caecal intubation, scope guide used, colonoscopist accreditation) and imaging modality. Lesion localisation was standardised with intra-operative location taken as the gold standard. Changes to surgical management were recorded.
Results:
364 cases were included; majority of lesions were colonic, solitary, malignant and in symptomatic referrals. 82% patients had their lesion/s correctly located at colonoscopy. Pre-operative CT visualised lesion/s in only 73% of cases with a reduction in screening patients (64 vs. 77%; p = 0.008). 5.2% incorrectly located cases at colonoscopy underwent altered surgical management, including conversion to open. Univariate analysis found colonoscopy accreditation, scope guide use, incomplete colonoscopy and previous abdominal surgery significantly influenced lesion localisation. On multi-variate analysis, caecal intubation and scope guide use remained significant (HR 0.35, 0.20â0.60 95% CI and 0.47; 0.25â0.88, respectively).
Conclusion:
Lesion localisation at colonoscopy is incorrect in 18% of cases leading to potentially significant surgical management alterations. As part of accreditation, colonoscopists need lesion localisation training and awareness of when inaccuracies can occur
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