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Drop Size Measurement Techniques for Agricultural Sprays:A State-of-The-Art Review
Full text linkPlant protection control based on the spray application of plant protection products is a very complex task depending on a series of factors, among which droplet size is the most influential for deposition and pesticide effectiveness. In fact, the adoption of the correct droplet size can ensure that the required dose reaches the target area and is not wasted, minimizes the off-target losses due to evaporation, drift and run-off and, at the same time, enhances the operator’s safety in terms of inhalation, ingestion and dermal exposure. In this paper, after defining some mean characteristic diameters helpful for a description of a drop population and focusing on the main drop size distribution functions for the statistical characterization of sprays, a critical analysis of known methods, both intrusive and non-intrusive, for drop size measurement is carried out by reviewing the literature. Among intrusive methods, the liquid immersion method and the use of water-sensitive papers are discussed, whereas, among non-intrusive methods, laser-based systems (laser diffraction, phase Doppler particle analysis) and high-speed imaging (shadowgrapy) are presented. Both types of method, intrusive and non-intrusive, can be used in machine-learning-based approaches exploiting regression techniques and neural network analysis
A simplified approach to capillary electrophoretic separation of polymerase chain reaction fragments of forensic interest
No full textHair analysis for abused drugs by capillary zone electrophoresis with field-amplified sample stacking.
No full textThe present paper describes the methodological optimisation and validation of a capillary zone electrophoresis method for the determination of morphine, cocaine and 3,4-methylenedioxymethamphetamine (MDMA) in hair, with injection based on field-amplified sample stacking. Diode array UV absorption detection was used to improve analytical selectivity and identification power. Analytical conditions: running buffer 100 mM potassium phosphate adjusted to pH 2.5 with phosphoric acid, applied potential 10 kV, temperature 20degreeC, injection by electromigration at 10 kV for 10 s, detection by UV absorption at the fixed wavelength of 200 nm or by recording the full spectrum between 190 and 400 nm. Injection conditions: the dried hair extracts were reconstituted with a low-conductivity solvent (0.1 mM formic acid), the injection end of the capillary was dipped in water for 5 s without applying pressure (external rinse step), then a plug of 0.1 mM phosphoric acid was loaded by applying 0.5 psi for 10 s and, finally, the sample was injected electrokinetically at 10 kV for 10 s. Under the described conditions, the limit of detection was 2 ng/ml for MDMA, 8 ng/ml for cocaine and 6 ng/ml for morphine (with a signal-to-noise ratio of 5). The lowest concentration suitable for recording interpretable spectra was about 10 - 20 times the limit of detection of each analyte. The intraday and day-to-day reproducibility of migration times (n = 6), with internal standardisation, was characterised by R.S.D. values <= 0.6%; peak area R.S.D.s were better than 10% in intraday and than 15% in day-to-day experiments. Analytical linearity was good with Rsup 2 better than 0.9990 for all the analytes
Capillary electrophoretic separation of vitamins in sodium dodecyl sulfate containing buffers with lower aliphatic alcohols and n-hexane as organic modifiers
No full textA Brief Review of Nozzle Spray Drop Size Measurement Techniques
No full textSpray application of Plant Protection Products (PPP) is affected by many factors, among which drop size distribution is the most important. In fact, the correct spray spectrum ensures the required dose on the target, minimizes off-target losses due to evaporation, drift and run-off, and enhances the operator safety in terms of inhalation and dermal exposure. This study reports a brief review of the most common drop size measurement techniques present in the literature
Measure of spray deposition in a 'tendone' vineyard produced by an air blast sprayer machine
No full textThis study reports the main results of a research aimed at evaluating the effects of airflow rate and volume rate on foliar deposits in a " tendone" vineyard when using an air blast sprayer with two counter-rotating fans and anterior intake. Experimental tests were replicated in two phenological stages (full flowering and berry touch), characterized by different Leaf Area Indices (2.21 and 5.83 m(2) m(-2)), considering two airflow rates (2.43 and 5.71 m(3) s(-1)), two volume rates (about 335 and 625 L ha(-1)) and keeping the forward speed constant (1.1 m s(-1)). Before tests, the sprayer was calibrated using a patternator purposely designed for "tendone" vineyards, achieving a distribution profile in agreement with the vineyard Leaf Area Index pattern. The results showed that foliar deposits were not affected by volume rate at either phenological stage, whereas increasing the airflow rate, they decreased significantly at full flowering (-30 % on the most exposed vegetation), and increased significantly at berry touch (+43 %)
Field-amplified sample stacking capillary zone electrophoresis applied to the analysis of opiate drugs in hair
No full textThe present paper describes the methodological optimization and validation of capillary zone electrophoresis (CZE) for the determination of major opiates (morphine, codeine, 6-monoacetylmorphine, acetylcodeine, heroin) in hair samples by using a field-amplified sample stacking injection before the separation in a binary running buffer (0.1 M sodium phosphate, pH 2.5, with 40% ethylene glycol). The applied potential was 20 kV, at 25°C. Detection was by UV absorption at the fixed wavelength of 214 nm or by recording the full spectrum between 190—400 nm, thus improving the analytical selectivity and identification power of CZE. Hair samples were liquid/liquid extracted; dried extracts, reconstituted with a low-conductivity solvent (0.1 mM phosphoric acid, with 80% 1-propanol), were injected by electromigration at 10 kV for 99 s, after a 0.5 mm plug of water. Under the described conditions, the limit of detection (with a signal-to-noise ratio of 3) in hair extracts was 100 pg/mL for codeine, 75 pg/mL for morphine and 6-monoacetylmorphine (6-MAM), 150 pg/mL for ethylmorphine, and 0.75 ng/mL for acetylcodeine and heroin. The precision of the method was validated for standards in pure solution by using internal standardization, providing for intraday and day-to-day assays, in terms of migration times, relative standard deviation (RSD) values ≤0.2%, and in terms of peak areas, RSD values <5.71
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