Volume Median Diameter Research Articles

Boundary protection based on the anti-icing thermal load surrogated model and the WRF icing meteorological prediction

PurposeThis paper aims to propose a method of the safety boundary protection for unmanned aerial vehicles (UAVs) in the icing conditions.Design/methodology/approachForty icing conditions were sampled in the continuous maximum icing conditions in the Appendix C of the Federal Aviation Regulation Part 25. Icing numerical simulations were carried out for the 40 samples and the anti-icing thermal load distribution in full evaporation mode were obtained. Based on the obtained anti-icing thermal load distribution, the surrogated model of the anti-icing thermal load distribution was established with proper orthogonal decomposition and Kriging interpolation. The weather research and forecasting (WRF) model was used for meteorological simulations to obtain the icing meteorological conditions in the target area. With the obtained icing conditions and surrogated model, the anti-icing thermal load distribution in the target area and the variation with time can be determined. According to the energy supply of the UAVs, the graded safety boundaries can be obtained.FindingsThe surrogated model can predict the effects of five factors, such as temperature, velocity, pressure, median volume diameter (MVD) and liquid water content (LWC), on the anti-icing thermal load quickly and accurately. The simulated results of the WRF mode agree well with the observed results. The method can obtain the graded safety boundaries.Originality/valueThe method has a reference significant for the safety of the UAVs with the limited energy supply in the icing conditions.

Liquid water content measurement with SEA multi-element sensor in CARDC icing wind tunnel: Calibration and performance

The measurement of cloud liquid water content (LWC) plays a critical role in the development of icing airworthiness standards for aircraft and the calibration of icing wind tunnels. The SEA multi-element sensor, the modern hot-wire device for LWC measurement, still faces several challenges for performance calibration due to the effects of the baseline drift and droplet retention characteristics. To fully calibrate the performance of the sensor, two wind tunnel tests were conducted in the China Aerodynamics Research and Development Center (CARDC) icing wind tunnel including a dry air calibration test and an icing cloud measurement test. Using the in-situ dry power calibration method developed in this study, the compensation function and the empirical formula of dry air Nusselt number for each sense element are obtained, and present great linear characteristics in the range of the test section velocity VTS from 40 to 110 m/s. However, there is an abnormal peak area of total power for the W1 element at the VTS of 120 and 130 m/s, which may be associated with significant water vapor condensation. The consistency and discrepancy of four LWC calculation methods via the combinations of dry and wet power calculation methods are assessed. Further, the LWC response characteristics of the sense elements are examined and the correlations of the droplet retention efficiency for the W2 and W3 elements are acquired as functions of median volume diameter. Finally, the measurement accuracy of the SEA multi-element sensor is validated compared to the icing blade device. It demonstrates that the uncertainty of the W1 element for the sensor is about ±5% at the low LWC and the W1 element has a better ability in the measurement of the high LWC.

Effect of spray droplet spectra on control of Poa annua with pronamide

AbstractAnnual bluegrass is a troublesome weed in turfgrass, with reported resistance to at least 12 herbicide sites of action. The mitotic-inhibiting herbicide pronamide has both preemergence and postemergence activity on susceptible annual bluegrass populations. Previous studies suggest that postemergence activity may be compromised due to lack of root uptake, as well as target-site- and translocation-based mechanisms. Research was conducted to determine the effects of spray droplet spectra on spray coverage and control of annual bluegrass with pronamide, flazasulfuron, and a mixture of pronamide plus flazasulfuron. Herbicides were delivered to annual bluegrass plants having two to three leaves via five different spray spectra based on volume median diameters (VMD) of 200, 400, 600, 800, and 1,000 µm. Fluorescent tracer dye was added to each treatment solution to quantify the effects of herbicide and spray droplet spectra on herbicide deposition. In another experiment, the efficacy of 0.58, 1.16, and 2.32 kg pronamide ha−1; 0.022, 0.044, and 0.088 kg flazasulfuron ha−1, or a combination of the two, were assessed in iteration with droplet spectrum sprays of 400 and 1,000 µm on two pronamide-resistant and two pronamide-susceptible annual bluegrass populations. Spray droplet spectrum affected the deposition of pronamide and flazasulfuron, applied alone and in combination. Pronamide foliar deposition decreased with increasing droplet spectra. Pronamide efficacy was affected by droplet spectrum, with the largest (1,000 µm) exhibiting improved control. Flazasulfuron efficacy and pronamide plus flazasulfuron efficacy were not affected by droplet spectra. Pronamide plus flazasulfuron mixture controlled all four populations more effectively than pronamide alone, regardless of droplet spectra. A mixture of pronamide plus flazasulfuron applied with relatively large droplets may be optimal for annual bluegrass control, which offers valuable insights for optimizing herbicide application and combatting herbicide resistance. However, applications in this controlled-growth pot study may not mimic conditions in which thatch and turfgrass canopy limit the soil deposition of pronamide.

Atomization of High Viscous Liquids Using a MEMS Vibrating Mesh With Integrated Microheater

Aerosol generation is important for a wide range of applications including drug delivery, additive manufacturing, spray cooling, and numerous other applications. However, current aerosol generation devices often have poor droplet uniformity or are limited to low viscosity liquids ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$&lt;$</tex-math> </inline-formula> 2 cp). This work presents the development of a Microelectromechanical systems vibrating mesh atomizer capable of atomizing higher viscosity fluids while maintaining high droplet size uniformity. The overall system consists of microfabricated silicon vibrating mesh atomizer, a piezoelectric film, and a flexible thin film microheater. The Si vibrating mesh atomizer was designed to increase atomization thresholds, while the microheater is designed to reduce liquid viscosity to meet the atomization threshold. Atomizers with varying nozzle dimensions were experimentally validated using liquids with varying viscosity and physiochemical properties, such as water, glycerol, propylene glycol, and vegetable glycerin. The microheater was designed to provide local rapid heating with low power consumption of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$&lt;$</tex-math> </inline-formula> 1 W. The droplet size distribution results show that when fluid viscosity increases, the volume median diameter of droplets increases, and the spray angle decreases. The Si-vibrating mesh atomizer was able to atomize liquids up to 49.73 cP at room temperature compared to normal metallic vibrating mesh atomizers which have a threshold of approximately 2 cP. The integrated heater enabled atomization of liquids with viscosities as high as 111 cP with low heating ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$&lt;$</tex-math> </inline-formula> 100 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ}$</tex-math> </inline-formula> C). 2023-0042

A unified synergistic retrieval of clouds, aerosols, and precipitation from EarthCARE: the ACM-CAP product

Abstract. ACM-CAP provides a synergistic best-estimate retrieval of all clouds, aerosols, and precipitation detected by the atmospheric lidar (ATLID), cloud-profiling radar (CPR), and multi-spectral imager (MSI) aboard EarthCARE (Earth Cloud Aerosol and Radiation Explorer). While synergistic retrievals are now mature in many contexts, ACM-CAP is unique in that it provides a unified retrieval of all hydrometeors and aerosols. The Cloud, Aerosol, and Precipitation from mulTiple Instruments using a VAriational TEchnique (CAPTIVATE) algorithm allows for a robust accounting of observational and retrieval errors and the contributions of passive and integrated measurements and for enforcing physical relationships between components (e.g. the conservation of precipitating mass flux through the melting layer). We apply ACM-CAP to EarthCARE scenes simulated from numerical weather model forecasts and evaluate the retrievals against “true” quantities from the numerical model. The retrievals are well-constrained by observations from active and passive instruments and overall closely resemble the bulk quantities (e.g. cloud water content, precipitation mass flux, and aerosol extinction) and microphysical properties (e.g. cloud effective radius and median volume diameter) from the model fields. The retrieval performs best where the active instruments have a strong and unambiguous signal, namely in ice clouds and snow, which is observed by both ATLID and CPR, and in light to moderate rain, where the CPR signal is strong. In precipitation, CPR's Doppler capability permits enhanced retrievals of snow particle density and raindrop size. In complex and layered scenes where ATLID is obscured, we have shown that making a simple assumption about the presence and vertical distribution of liquid cloud in rain and mixed-phase clouds allows improved assimilation of MSI solar radiances. In combination with a constraint on the CPR path-integrated attenuation from the ocean surface, this leads to improved retrievals of both liquid cloud and rain in midlatitude stratiform precipitation. In the heaviest precipitation, both active instruments are attenuated and dominated by multiple scattering; in these situations, ACM-CAP provides a seamless retrieval of cloud and precipitation but is subject to a high degree of uncertainty. ACM-CAP's aerosol retrieval is performed in hydrometeor-free parts of the atmosphere and constrained by ATLID and MSI solar radiances. While the aerosol optical depth is well-constrained in the test scenes, there is a high degree of noise in the profiles of extinction. The use of numerical models to simulate test scenes has helped to showcase the capabilities of the ACM-CAP clouds, aerosols, and precipitation product ahead of the launch of EarthCARE.

An Investigation into Thermal Performance of Mist Water System and The Related Consumption Energy

Experimental tests were conducted to investigate the thermal performance (cooling effect) of water mist system consisting of 5μm volume median diameter droplets in reducing the heat gain entering a room through the roof and the west wall by reducing the outside surface temperature due to the evaporative cooling effect during the hot dry summer of Baghdad/Iraq. The test period was Fifty one days during the months May, June, and July 2012. The single test day consists of 16 test hours starting from 8:00 am to 12:00 pm. The results showed a reduction range of 1.71 to 15.5℃ of the roof outside surface temperature and 21.3 to 76.6% reduction in the daily heat flux entering the room through the roof compared with the case of not using water mist system. Also the results show a reduction range of 1.3 to 18.8℃ in the wall outside surface temperature. Finally numerical simulation with ANSYS-FLUENT.14 was conducted to compare its results with the experimental results of the roof and wall tests.

Robust Optimization of a Thermal Anti-Ice Protection System in Uncertain Cloud Conditions

This paper presents a framework for the robust optimization of the heat flux distribution for an anti-ice electrothermal ice protection system under uncertain conditions. The considered uncertainty regards a lack of knowledge concerning the characteristics of the cloud, i.e., the liquid water content and the median volume diameter of water droplets, and the accuracy of measuring devices, i.e., the static temperature probe. Uncertain parameters are modeled as random variables, and two sets of bounds are investigated. A forward uncertainty propagation analysis is carried out using a Monte Carlo approach exploiting a surrogate models. The optimization framework relies on a gradient-free algorithm (mesh adaptive direct search), and two different objective functions are considered, namely, the 95 quantile of the freezing mass rate and the statistical frequency of the fully evaporative operating regime. The framework is applied to a reference test case, revealing a potential to improve the heat flux distribution of the baseline design. A new heat flux distribution is proposed, and it presents a more efficient use of the thermal power, increasing flight safety even at nonnominal environmental conditions.

Abstracts from The Aerosol Society Drug Delivery to the Lungs 33.

Abstracts from The Aerosol Society Drug Delivery to the Lungs 33.

Optimization of operating parameters for spraying microbial (Bacillus thuringiensis and Beauveria bassiana) based bio-pesticide solutions for foliar application

Exposure to mechanical stresses developed due to different components of spraying system may cause permanent damage to the microbes of bio-pesticide solutions. To achieve maximum effectiveness of spray application, proper selection of nozzle size and operating pressure is critical. Two different classes of bio-pesticides viz. bacterial-based Bacillus thuringiensis (BBP solution) and fungal-based Beauveria bassiana (FBP solution) were evaluated for spray application by three hollow cone nozzles (1.14, 2.35 and 3.56 mm in diameter) at four operating pressures (145, 245, 345 and 445 kPa). It was observed that viability of bio-pesticide solutions increases with decrease in operating pressure and increase in nozzle size. The nozzle orifice diameter and operating pressure of the spraying system were optimized to get desired application rate, volume median diameter (VMD) and coefficient of variation (CV) of spray for maximum microbial viability of bio-pesticide solutions. The optimized values of application rate (323.94-and 325.58 L ha−1), VMD (225.88 and 231.89 µm), CV (84.49 and 85.99%) and viability (6.63 × 106 and 6.06 × 106 cfu ml−1) were obtained for BBP and FBP solutions, respectively at nozzle orifice size of 3.56 mm and 145 kPa operating pressure.

"H" sprayer effect on liquid deposition on cucumber leaves and powdery mildew prevention in the shed.

To clarify the effect of droplet size on solution deposition and powdery mildew control on greenhouse cucumber leaves, the effect of volume median droplet diameter (VMD) on solution deposition and maximum retention, as well as the effect of flusilazole on powdery mildew control on cucumber, was determined using the stem and leaf spray method. The VMD of the typical fan nozzles (F110-01, F110-015, F110-02, F110-03) of the selected US Tee jet production differs by approximately 90 μm. The results showed that the deposition of flusilazole solution on cucumber leaves decreased as the VMD of the droplets increased and that the deposition of the solution in the treatments with VMD of 120, 172, and 210 μm decreased by 22.02%, 10.37%, and 46. 97%, respectively, compared to that observed with treatment with 151 μm VMD. The deposition of the solution on cucumber leaves showed the highest deposition efficiency of 63.3% when the applied solution volume was 320 L/hm2, and the maximum stable retention of the liquid on the leaves was 6.6 µl/cm2. The control effects of different concentrations of flusilazole solution on cucumber powdery mildew differed significantly, and the best control effect was achieved at the dosage of 90 g/hm2 of the active ingredient, which was 15%-25% higher than that observed at the dosage of 50 and 70 g/hm2 of the active ingredient per hectare. A significant difference in the effect of droplet size on the control of cucumber powdery mildew was observed at any specific liquid concentration. Nozzle F110-01 showed the best control effect when the dosage of the active ingredient was 50 and 70 g/hm2 per hectare, which did not differ significantly from that observed with nozzle F110-015 but differed significantly from those observed with nozzles F110-02 and F110-03. Hence, we concluded that the use of smaller droplets with VMD of 100-150 μm, i.e. the choice of F110-01 or F110-015 nozzles, for application on the leaf parts of cucumber in the greenhouse under conditions of high liquid concentration, can significantly improve the effective use of pharmaceuticals and the disease control effect.

Deposition of spray droplets by four spray nozzles and two working pressures

The deposition of spray droplets on the target can be influenced by the type spray nozzle used, as well as the employed working pressure. Thus, with the commercial availability of new spray nozzles, performance studies with the new models become necessary. This study was carried out to evaluate ground deposition of spray droplets by four models of spray nozzles, at two working pressures. The experiment was conducted in Dourados/MS, in September 2020, with strip design and 4x2 factorial scheme, with five repetitions. Four spray nozzles were used (single flat fan, ST-IA 02 model; angle flat fan MUG 02; hollow cone MGA 02; and double flat fan ST-IA/D 02), working at 30 and 50 psi pressures. The distance between each nozzle was 50 cm, 60 cm above the ground. Water-sensitive paper was used and, immediately after application, the paper was scanned using the DropScan® tool. Subsequently, the number of droplets, coverage, amplitude, dispersion, Volume Median Diameter (VMD), Number Median Diameter (NMD), DV09, and DV01 were evaluated. The hollow cone spray nozzle provided a higher number of droplets and greater coverage compared to the other nozzles for the studied weather conditions.

Compatibility and aerosol characteristics of beclomethasone mixed with N-acetylcysteine

Mixing different kind inhalation medications for simultaneous inhalation is widely used in the treatment of chronic respiratory diseases, and it can minimize the administration time and improve patient adherence. To our knowledge, it is unclear whether beclomethasone (BDP, Clenil®) can bemixed with acetylcysteine (NAC, Fluimucil®), because the in vitro physico-chemical compatibility and aerosol characteristics of the mixture are unknown. In this study, we investigated physical compatibility, including the appearance, pH, osmotic pressure and chemical stability, as well as aerosol characteristics, including particle size corresponding to 10%/50%/90% of the cumulative percentage of total particle volume (X10/X50/X90), volume median droplet diameter (VMD), mass median aerodynamic diameter (MMAD), fine particle fraction (FPF), fine particle dose (FPD) and geometric standard deviation (GSD), delivery rate, and total delivery of the above solutions. After mixing, there were no significant changes in visual appearance, pH, osmolality and drug content of the mixtures at room temperature for 12 h. The FDP of BDP in the mixture decreased by 16.49%, whereas the NAC increased by 10.85%. The delivery rates of BDP and NAC in the mixture decreased by 66.05% and 45.54%, and total delivery increased by 13.20% and 25.29%, respectively. However, the MMAD, FPF, particle size and GSD of the mixture were almost unchanged. We demonstrated that these admixtures are physico-chemically compatible but that coadministration of beclomethasone with acetylcysteine can markedly affect output and aerosol characteristics.

Simulation and sensitivity analysis for cloud and precipitation measurements via spaceborne millimeter-wave radar

Abstract. This study presents a simulation framework for cloud and precipitation measurements via spaceborne millimeter-wave radar composed of eight submodules. To demonstrate the influence of the assumed physical parameters and to improve the microphysical modeling of the hydrometeors, we first conducted a sensitivity analysis. The results indicated that the radar reflectivity was highly sensitive to the particle size distribution (PSD) parameter of the median volume diameter and particle density parameter, which can cause reflectivity variations of several to more than 10 dB. The variation in the prefactor of the mass–power relations that related to the riming degree may result in an uncertainty of approximately 30 %–45 %. The particle shape and orientation also had a significant impact on the radar reflectivity. The spherical assumption may result in an average overestimation of the reflectivity by approximately 4 %–14 %, dependent on the particle type, shape, and orientation. Typical weather cases were simulated using improved physical modeling, accounting for the particle shapes, typical PSD parameters corresponding to the cloud precipitation types, mass–power relations for snow and graupel, and melting modeling. We present and validate the simulation results for a cold-front stratiform cloud and a deep convective process with observations from a W-band cloud profiling radar (CPR) on the CloudSat satellite. The simulated bright band features, echo structure, and intensity showed a good agreement with the CloudSat observations; the average relative error of radar reflectivity in the vertical profile was within 20 %. Our results quantify the uncertainty in the millimeter-wave radar echo simulation that may be caused by the physical model parameters and provide a scientific basis for optimal forward modeling. They also provide suggestions for prior physical parameter constraints for the retrieval of the microphysical properties of clouds and precipitation.

Numerical simulation of two-dimensional transmission line icing and analysis of factors that influence icing

The formation of ice on electrical transmission lines poses an increasingly substantial safety hazard. In this study, a two-dimensional transmission line icing model was established to predict the shape of the icing. The airflow field and convective heat transfer were calculated using Fluent software, and a discrete phase model (DPM) based on the Lagrange method was used to calculate the water droplet collection coefficient on the surface of the transmission line. The Messinger thermodynamic model was programmed using the user-defined function (UDF) of Fluent, and the icing shape and icing thickness on the surface were calculated. The effects of wind speed, median volume diameter (MVD) of water droplets, temperature, liquid water content, wind direction angle, and electric field intensity on the icing characteristics of transmission lines were considered. The forced vibration of the transmission line was simulated using the UDF, and its influence on icing characteristics was thoroughly analyzed. Furthermore, the influence law of the vibration amplitude and frequency on the local water drop collection coefficient and ice shape was determined. The results elucidate the effects of the aforementioned parameters on transmission line icing. These findings provide a reference for future efforts to mitigate the impact of transmission line icing. Compared with other studies, this study has considered the influencing factors more fully, predicted the ice shape under different conditions more comprehensively, and can be more pertinently applied to different regions with different meteorological conditions.

Influence of air mass origin on microphysical properties of low-level clouds in a subarctic environment

Abstract. In this work, an analysis was performed to investigate how different long-range transport air masses can affect the microphysical properties of low-level clouds in a clean subarctic environment. The cloud measurements included in situ and remote sensing ground-based techniques and were conducted during eight Pallas Cloud Experiments (PaCEs) held in the autumn between 2004 and 2019. Each PaCE was carried out at the Pallas Atmosphere-Ecosystem Supersite, located in the Finnish subarctic region. Two cloud spectrometer ground setups were installed on the roof of the station to measure cloud microphysical properties: the cloud, aerosol and precipitation spectrometer (CAPS) and the forward-scattering spectrometer probe (FSSP). Air mass histories were analyzed using the Lagrangian FLEXible PARTicle dispersion model (FLEXPART) in order to investigate the differences between five distinct source regions (“Arctic”, “Eastern”, “Southern”, “Western” and “Local”). We observed clear differences in the cloud microphysical properties for the air mass source regions. Arctic air masses were characterized by low liquid water content (LWC), low cloud droplet number concentration (Nc) and comparatively large median volume and effective droplet diameter. The Western region (marine North Atlantic) differed from the Arctic by both higher Nc and LWC. The Eastern region (continental Eurasia) only had a little higher LWC than the Arctic but substantially higher Nc and a smaller droplet diameter. The Southern region (continental Europe) had high Nc and LWC and a very similar droplet diameter to the Eastern region. Finally, the relationship between Nc and droplet size (i.e., the Twomey effect) was characterized for the different source regions, indicating that all region clouds were sensitive to increases in Nc.

Optimization-Design and Atomization-Performance Study of Aerial Dual-Atomization Centrifugal Atomizer

The aerial atomizer is the most essential component of the plant protection UAV (unmanned aerial vehicle). However, the structural optimization of existing aerial atomizers lacks comprehensive consideration of spray parameters and structural parameters, and there is a shortage of available atomizer spray models, resulting in the unstable effect of UAV application. In our previous work, an aerial dual-atomization centrifugal atomizer was developed. In order to obtain an aerial atomizer with good atomization effect and its atomization model, structural optimization at different rotation speeds and flow rates of the atomizer, and its atomization performance, are studied in this paper. Firstly, with the droplet volume median diameter (VMD) and spectral width (SRW) as the evaluation index, through the single-factor, Plackett–Burman and Box–Behnken tests, the influence of rotation speed, flow rate, tooth number and tooth shape were studied. The regression models of the droplet VMD and SRW were established using multiple quadratic regression fitting of the test data. Secondly, in order to achieve the lowest droplet VMD and SRW, the response surface method and post-hoc multiple comparison method were used to obtain the optimized structure of the atomizer’s rotation ring at different rotation speeds (600–7000 r/min) and flow rates (500–1000 mL/min). Lastly, with the effective swath width (ESW) of the optimized atomizer as the evaluation index, through the Box–Behnken test, the influence of rotation speed, flow rate and spray height were studied. The multiple quadratic regression model of ESW was established with the test data. The test results indicated that rotation speed, flow rate and tooth number had a significant effect on droplet VMD and SRW; tooth shape had no significant effect on the droplet VMD and SRW, however, the square tooth shape had the best atomization effect; and rotation speed, flow rate and spray height had a significant effect on ESW. The optimized structural parameters were tooth shape: square, and tooth number: 20. The determination coefficient R2 of the regression model of VMD, SRW and ESW were 0.9976, 0.9770 and 0.9974, respectively, which indicates that the model was accurate, and can evaluate and predict the spray effect. This paper provides an optimized dual-atomization centrifugal atomizer, and its regression models of VMD, SRW and ESW for UAV applications can provide a reference for efficient UAV spraying.

Measuring Rainfall Kinetic Power in Two Sicilian Experimental Areas by Drop-Size Distribution Data

The rainfall kinetic energy, which affects soil erosion processes, can be calculated by the drop-size distribution (DSD) and falling velocity. This study presents the outcomes derived by the DSDs recorded with the same optical disdrometer in two experimental areas, located in Sicily (southern Italy). Specifically, the DSDs were recorded from March 2017 to December 2019 at Sparacia and from June 2006 to April 2014 at Palermo. The aims of this paper are both to compare the DSDs for the two sites and to evaluate the applicability of Gamma theoretical distribution. Moreover, the relations of rainfall kinetic power vs. rainfall intensity are assessed. Differences in DSDs, especially for rainfall intensity I lower than 100 mm h−1, are detected, while they are less evident for the highest I values. The kinetic power per unit volume of rainfall varies between the two sites and can be considered roughly coincident only for I higher than 100 mm h−1. The observed kinetic power-rainfall intensity relations are not well described by the equations by Wischmeier and Smith and Brown and Foster. Finally, the reliability of a theoretical relationship for estimating the kinetic power by I and the median volume diameter D0 is positively tested for the Palermo dataset, while it is found to be reliable only for D0 greater than 0.17 cm for the Sparacia dataset.

Low-volume precision spray for plant pest control using profile variable rate spraying and ultrasonic detection.

Spraying chemical pesticides is one of the important means to control plant pest, and the profile variable spraying is an important technology to achieve precise pesticide application. A profiling tracking control method and an improved algorithm based on CMAC-PID (Cerebellar Model Articulation Controller- Potential Induced Degradation) were proposed in the paper. The test results of the sprayer profiling tracking of the tree canopies showed that the profiling control system using the improved algorithm had significantly better dynamic tracking performance, and the overall mean tracking error was reduced by 35.0%, compared with the traditional CMAC-PID. A spray flow calculation method based on tree canopy volume and leaf area density was proposed. Outdoor testing of the profile variable spraying and conventional spraying was carried out. There was no significant difference between the two spraying methods in terms of droplet coverage, VMD (Volume Median Diameter), NMD (Number Median Diameter), spray quality parameter and relative span coefficient, as well as droplet deposition density. The spray coefficient of variation was reduced by 25.9% and 21.9% inside and outside the tree canopy, respectively. The mean value of the ground deposition coverage of the profile variable spraying and the traditional spray was 13.0% and 33.2%, respectively, indicating a significant impact on the ground droplet deposition coverage by the two spraying methods. The spray flow rate of the profile variable spraying could be decreased by 32.1% compared to the conventional spraying. Profile variable spraying would reduce the cost associated with pesticide use and environmental pollution.

STUDY OF DRY ICE GROWTH ON DUPLEX CYLINDERS

A study of dry ice growth on bundled (duplex) cylinders has been performed using icing wind tunnel experiments and computational fluid dynamics (CFD) numerical simulations. The aim of this study is to "fill the gaps" in the works of Wagner (2010) and Qing et al. (2018). The numerical simulations cover a range of possible icing conditions by varying the operating wind speed, median volume diameter, and for some cases-the angle of incidence between the cylinders. The obtained results for the 0&amp;deg; AoA show that the accreted ice masses ratio between the leeward and windward cylinder varies from &amp;#126; 100&amp;#37; to &amp;#126; 30&amp;#37;. The accreted ice masses ratio decreases with the increase in the wind speed and/or median volume diameter. For the cases with non-zero AoA, the accreted ice masses become approximately equal, when the AoA is large enough to produce a vertical separation equal or greater to one cylinder diameter.

Determination of the Application Parameters of Spraying Drones for Crop Production in Hazelnut Orchards

Hazelnut, which has the most common cultivation area after almonds and walnuts among the shell fruits in the world, contains high levels of fat, protein, carbohydrates, various minerals and vitamins. Hazelnut has a broad growing area around the world, and Turkey accounts for 58% of world production with 776,000 tons annually. With this production capacity, Turkey ranks first in hazelnut production over the world. Harmful insects in hazelnut trees are the main factors that reduce hazelnut yield and quality. Pesticides are sprayed with backpack sprayers in the fight against these pests in hazelnut trees. Farmers are directly exposed to pesticides in these practices, which use high amounts of pesticides and water. In recent years, the use of unmanned agricultural vehicles in agriculture has increased. Drones are also used in pesticide applications in agriculture. In this study, the suitability of pesticide applications with the drone in hazelnut fields in Giresun province in terms of field conditions and spraying efficiency was investigated. In September 2021, applications were made with DJI Agras MG-1P model spraying drone in a selected hazelnut orchard in Uzgur village of Giresun province. The drone has 4 Teejet XR11001VS fan jet nozzles. Water-sensitive papers were placed on different regions on the hazelnut trees to be sprayed for drop measurements. In the experiments, hazelnut trees were sprayed using water at different heights and spraying rates. 6 flights were carried out at 1.5 and 2 meters altitudes and 1, 2 and 3 L.da-1 spray rates, and three hazel trees were sprayed as three repetitions in each flight. After the flight trials, the water-sensitive papers were scanned on the scanner, and the volume median diameters and the number of droplets per square centimetre were calculated in the DepositScan software. As a result of the analyses done, it was observed that the applications performed at 1 L.da-1 and 2 L.da-1 spray rates would not be sufficient in terms of spraying efficiency. As the drone flight altitude increased, the accumulation of the drops on the inner leaves decreased. In terms of drop distribution, the most homogeneous application parameter was found to be 1.5 meters high above the upper leaves of the hazel trees and 3 L.da-1 spray rate.