Feasibility study on hexacopter UAV based sprayer for application of environment-friendly biopesticide in guava orchard

Aim: To study the feasibility of hexacopter UAV based sprayer for application of environment-friendly biopesticide in guava orchard. Methodology: Field experiments were conducted in Punjab (India) during 2020. UAV was evaluated for spraying environment-friendly bio-pesticidein guava orchard. UAV was operated at 2.0 m height above the tree top.The water and oil sensitive papers were fixed on the outer side as well as inside of selected guava trees at four different canopies. Organic neem seed kernel based azadirachtin 0.15% EC biopesticide was used at recommended dose. After spraying, all water and oil sensitive papers were collected for further laboratory analysis. All spray quality parameters, i.e., coverage (%), droplet density (droplets cm-2), droplet size (µm) and uniformity coefficient were determined. For the efficacy of drone sprayer insects were counted before and 1, 2, 7 days after spray (DAS) and reduction in number of insects was calculated. Results: The on-flight field capacity of spraying with UAV was 3.0-3.3 ha h-1 whereas actual field capacity was found to be 2.0-2.3 ha h-1. The total mean coverage area was found in the range of 2.67-10.67%. The maximum coverage was at the top canopy (inner and outer) of tree which was significantly higher than all other observation points on the canopy. The mean droplet density was found in the range of 14.67-28.33 droplets cm-2. The highest droplet density (28.33 droplets cm-2) was found at the top outer side of the tree canopy. The volume median diameter was found in the range of 208.0-418.3 µm whereas, number median diameter was in the range of 138 to 269 µm. The percent reduction in aphid population 1, 2 and 7 days after spray (DAS) was 38.06, 68.28 and 62.69%, respectively whereas it was 47.95, 78.69 and 70.90% with knapsack sprayer. Interpretation: Hexacopter UAV sprayer is effective in terms of quality of spray and effective control of aphid population.

Effect of Nozzle Type and Adjuvants on Spray Coverage on Apple Leaves

Three non-ionic adjuvants, Agral, Silwet, and Greemax, at three concentrations, were applied on apple leaves with the use of hollow cone nozzles (TR) and air-induction nozzles (ID) to verify the assumption that adjuvants may improve spray coverage obtained by coarse droplets, and thereby ensure both satisfactory application quality and an environmental advantage. Spray coverage and droplet density were measured on both sides of the leaves. The adjuvants enhanced the spray coverage when applied at a certain concentration level. In general, the adjuvant coverage produced by the ID nozzles equaled the pure water coverage produced by the TR nozzles, thereby showing the adjuvants’ potential to compensate for the lower spray coverage usually obtained by coarse spray. A higher spray coverage was obtained on the lower side of leaves, which is discussed in terms of leaf surface properties. In the experiment with the mixture of Silwet and the fungicide Delan (dithianon), the product interacted with the adjuvant, resulting in the reversed picture of spray coverage and droplet density on the upper and lower leaf sides compared to the results obtained for the adjuvant alone. The combination of coarse spray nozzles with adjuvants may reduce environmental pollution without compromising the quality of spray applications in fruit growing.

Temperature Activated Dimensionality Crossover in the Nucleation of Quantum Dots by Droplet Epitaxy on GaAs(111)A Vicinal Substrates

A temperature activated crossover between two nucleation regimes is observed in the behavior of Ga droplet nucleation on vicinal GaAs(111)A substrates with a miscut of 2° towards $$(\bar{1}\bar{1}2)$$ ( 1 ¯ 1 ¯ 2 ) . At low temperature (<400 °C) the droplet density dependence on temperature and flux is compatible with droplet nucleation by two-dimensional diffusion. Increasing the temperature, a different regime is observed, whose scaling behavior is compatible with a reduction of the dimensionality of the nucleation regime from two to one dimension. We attribute such behavior to a presence of finite width terraces and a sizeable Ehrlich-Schwöbel barrier at the terrace edge, which hinders adatom diffusion in the direction perpendicular to the steps.

Pesticide Application Quality With Alternative Use of Water Sensitive Paper

The water sensitive paper is commonly used in the uniformity and distribution ratings of the spray droplets pattern; however, this technology still has a high cost. In this way, the present work had as objective to evaluate the quality of deposition of spray drops in different types of papers sensitive to water. The test was carried out in a wind tunnel built inside the multi-sport gymnasium of the State University of West Paran&aacute;-campus of Cascavel-PR. A semi-automated nozzle transition prototype was used to perform the tests. The variables evaluated were number of diameters, dispersion, volumetric medium diameter (VMD), droplet density, cover and droplet volume. The treatments consisted of four different types of paper compared to the water sensitive paper (control), and two nozzles. Cardboard paper stood out among the others at the cost of approximately 1% of a water-sensitive paper slip. The water sensitive paper used in agriculture can be replaced by alternative papers more economically viable and easily found in the market.

PONTAS TIPO CONE COM VARIAÇÃO DA TAXA DE APLICAÇÃO E VELOCIDADE NA CULTURA DO ALGODOEIRO

A Ramulária é uma das principais doenças fungicas do algodoeiro, trazendo consequências graves para sua produtividade e qualidade de fibras. Com o intuito de abater os gastos e melhorar os parâmetros da aplicação, o trabalho tem por objetivo avaliar diferentes tipos de pontas de jato cônico e pingente, variando a taxa de aplicação e velocidade na pulverização do algodoeiro. Foram utilizadas pontas de jato cone vazio e cheio de diferentes fabricantes e também pingente associado a ponta cone vazio. As velocidades de deslocamento do pulverizador avaliadas foram 20 e 27 km h-1. As taxas de aplicações foram de 50 e 80 L ha-1. Os parâmetros avaliados foram: DMV, amplitude relativa (dispersão), volume, densidade e cobertura. O DMV foi satisfatório para todos os tratamentos. A ponta P2 obteve resultados inferiores nos parâmetros densidade de gotas, DMV e dispersão. Na velocidade de 27 km h-1 os parâmetros volume de aplicação, densidade e cobertura obtiveram melhores resultados em comparação com a velocidade de 20 km h-1. A taxa de aplicação mais elevada melhorou os parâmetros de qualidade de aplicação na densidade de gotas, cobertura e volume. O acessório pingente não obteve resultado significativo para densidade, dispersão, volume e cobertura na cultura do algodoeiro.Palavras-chave: algodão, qualidade de gotas, tecnologia de aplicação. CONE TYPE NOZZLES WITH VARIATION OF SPRAY RATE AND SPEED IN COTTON CULTURE ABSTRACT:Ramularia is one of the main fungal diseases of cotton, with serious consequences for its productivity and fiber quality. In order to reduce costs and improve the parameters of the application, the objective of this work is to test different types of conical and pendant jet tips, varying the rate of application and speed of cotton spraying. We used empty cone tips filled with different manufacturers and also pendant associated with empty cone tip The velocities evaluated were 20 and 27 km h-1. The application rates were 50 and 80 L ha-1. The parameters evaluated were: DMV, relative amplitude (dispersion), volume, density and coverage. DMV was satisfactory for all treatments. The full cone jet tip obtained lower results in the parameters of droplet density, DMV and dispersion. At the top speed the parameters application volume, density and coverage obtained better results compared to the lowest speed. The higher application rate improved the application quality parameters in droplet density, coverage and volume. The pendant accessory did not obtain significant results for density, dispersion, volume and coverage in the cotton crop.Keywords: cotton, drops quality, application technology.

Systems and rates of aerial application of fungicides in irrigated rice

ABSTRACT The present research studied the performance of flat-fan and hollow-cone nozzles, with application rates of 20 and 30 L ha-1, and rotary disc atomizer with application rates of 10 and 15 L ha-1. The test was conducted with a fungicide spray tank composed of Azoxystrobin + Difenoconazole, in which the density and penetration of droplets into the canopy were evaluated using a water-sensitive paper and the distribution of the active ingredients in the plant was evaluated through the chromatographic analysis. Higher application rates resulted in higher droplet density in the upper stratum of plants. In all treatments, the penetration of the droplets was 26% into the middle stratum and 23% into the lower stratum, in relation to the top of the crop, resulting in an average 25% penetration of droplets into the leaf canopy. The active ingredients were distributed in greater quantity in the upper stratum of the plant. For the same weight, the upper part of the ‘Puitá Inta CL’ rice cultivar has a leaf area 6.4 times larger than the lower part. It was concluded that higher application rate leads to higher droplet density in the upper stratum of the leaf canopy and that all systems and application rates promoted similar penetration of droplets into the canopy.

Concentric GaAs nanorings growth modelling

The nanostructures formation process using the droplet epitaxy technique was investigated by Monte Carlo simulation. The simulation was fulfilled for two-dimensional and three-dimensional geometry substrates. The nanostructures morphology dependence on the growth temperature was presented. Crystal clusters, single and double rings were observed. The nanostructures shape was shown to be determined by the gallium diffusion length. The conditions of double rings formation during the droplet epitaxy were considered using analytical and numerical approaches. The factors that determine the rings location and shape were analyzed. The growth morphology was demonstrated to be dependent on the initial distance L between the droplets. The double ring formation was possible at a low droplet density only, when the As-stabilized region could be created between the droplets.