A Bias Gantry Profiling Boom Sprayer for Orchard Protection

An air-assisted sprayer sends liquid medicine to a canopy of orchard plants for protection. However, the inherent drift in this method lowers the pesticide utilization. To meet the gardening requirements of a short-anvil densely planted apple orchard, a profiling boom sprayer was designed, and the operation requirements and prototype operation parameters of plant protection were determined. The droplet depositions in the upper, middle, and lower layers of the targets and in the inner, middle and outer rings were analyzed in field experiments. The standard deviations of the droplet deposition coverage rates on free, slender, and high spindles at different heights were 4.43, 2.82, and 5.29, respectively, and those of the droplet deposition densities were 5.97, 4.98, and 6.15, respectively. All p-values exceeded 0.05, indicating that droplets from the outer ring were uniformly distributed at different canopy heights. The average droplet deposition density exceeded 150 grains·cm-2 in the outer and center rings of the three tree-shaped targets, and reached 100.60 grains·cm-2 in the inner ring. The droplet deposition coverage rates on the free, slender, and high spindles in the inner ring were 37.41%, 36.69%, and 35.47%, respectively, indicating that the droplet penetration ability of the profiling boom sprayer meets the requirements of plant protection. The developed profiling boom sprayer has improved the inherent serious drift problem of the air blower sprayer, and has provided inspiration for the research and development of orchard plant protection machinery.Materials and Methods: water-sensitive paper produced by Liuliu Shanxia Plant Protection Technology Co., Ltd. (China); the profiling boom sprayer; a tractor; a wind-speed measuring instrument (AS856S, Shanghai Xima Technology (Group) Co., Ltd., Shanghai, China); a temperature and humidity measuring instrument (RC-4, Jiangsu Jingchuang Electric Co., Ltd., Jiangsu, China);, double-sided tape; a box ruler; a stopwatch and a scanner. The water-sensitive paper was cut into 3 cm × 2 cm rectangular units, and its back side was pasted to the apple trees of the test target with a small amount of double-sided tape. Facing the east, south, west, and north directions, papers sprayed by the inner, middle and outer rings were pasted on the top, middle and bottom layers of the fruit tree canopy (Dong et al., 2018, Fig.5a). To avoid disturbance from spray drift, six fruit trees were selected as the test targets at intervals of their tree shapes, and 648 water-sensitive papers in total were pasted.Results: After averaging over height, the standard deviations of the droplet deposition coverage rates of the free, slender, and high spindles were 4.43, 2.82, and 5.29 respectively, and those of the droplet deposition density were 5.97, 4.98, and 6.15 respectively. All p-values exceeded 0.05. The average droplet deposition densities of the three tree-shaped targets exceeded 150 grains·cm-2 in the center and outer rings. The average droplet deposition density in the inner ring was 100.60 grains·cm-2, and the droplet deposition coverage rates of the free, slender, and high spindles were 37.41%, 36.69%, and 35.47%, respectively. Averaged over the four directions, the coverage rate in the outer ring was 41.46% higher than in the center ring, and 90.87% higher than in the inner ring. Meanwhile, the average coverage rate was 34.93% higher in the center ring than in the inner ring.Discussion: The outer ring of the profiling boom sprayer evenly distributed the droplets at different heights. The growths of the droplet deposition coverage rates were similar, and the droplet penetrations in different rings were consistent. Although the droplet penetration of the inner ring was poorer in the horizontal than center and outer ring in the vertical direction, the blades of the inner ring were sprayed sufficiently to meet both the quality assessment of plant protection operations and the design operating requirements of the profiling boom sprayer.

A Theoretical Study of H2S Toxic Gas Adsorption on Pristine and Doped Monolayer (AlN)21 Using Density Functional Theory

Been studying the interactions between graphene - like aluminium nitride P(AlN)21 nano ribbons doped and defect (AlN)21Sheet, Molecules and small toxic gas molecules ( H2S), were built for two different adsorption sites on graphene like aluminium nitride P(AlN)21. this was done by employing B3LYP density functional theory (DFT) with 6-31G*(d,p) using Gaussian 09 program, Gaussian viw5.0 package of programs and Nanotube Modeller program 2018. the adsorptions of H2S on P(AlN)21, (C) atoms-doped P(AL-N)20 sheet, D-P(AL-N)20 and D-(C)atoms-doped P(AL-N)19 (on atom) with (Ead) (-0.468eV),(-0.473 eV), (-0.457 eV), (-0.4478 eV) and (-0.454 eV), respectively, (Ead) of H2S on the center ring of the P(AL-N)21, (C) atoms-doped P(AL-N)20 sheet, D-P(AL-N)20 and D-(C,B)atoms-doped P(AL-N)19 sheet are (-0.280 eV),(-0.465 eV), (-0.405 eV), (-0.468 eV) and -0.282 eV), respectively, are weak physisorption . However, the adsorptions of H2S, on the ((AlN)20 -B and D- (AlN)19 -B), (on atom N and center ring the sheet) are a strong chemisorption because of the (Ead) larger than -0.5 eV, due to the strong interaction, the ((AlN)20-B and D-(AlN)19-B), could catalyst or activate, through the results that we obtained, which are the improvement of the sheet P(AlN)21 by doping and per forming a defect in, it that can be used to design sensors. DOI: http://dx.doi.org/10.31257/2018/JKP/2020/120210

Selective bond formation triggered by short optical pulses: quantum dynamics of a four-center ring closure

Making bonds with attopulses: quantum dynamics of the ring closure of norbornadiene to quadricyclane.

A Compact CPW-Fed Low-Profile Wideband Circularly Polarized Slot Antenna with a Planar Ring Reflector for GNSS Applications

A compact low-profile wideband circularly polarized slot antenna for global navigation satellite system (GNSS) is presented. The antenna comprises a planar slot radiator with a coplanar waveguide (CPW) feed and a modified ring-shaped reflector to achieve unidirectional radiation. The modified reflector is an inner square patch with four slantly cut corners, a center ring, and an outer ring with a notch; they significantly reduce the separation between the antenna radiator and reflector and therefore the overall antenna height. The overall dimensions are λ0/3 × λ0/3 × λ0/30 (λ0 denotes the free space wavelength at lower frequency). The measured −10 dB bandwidth of |S11|, 3-dB axial ratio (AR) bandwidth, and maximum gain are of 1.53–2.28 GHz, 1.558–1.672 GHz, and 5.87 dBi, respectively. The proposed antenna is simple without any additional feeding networks or shorting probes.

Numerical Study of Combinations of Strut and Cavity in a Round Supersonic Combustor

Different strut-cavity configurations and fuel injection patterns employed in a round supersonic combustor are numerically investigated. A new parameter defined as an ideal nozzle outlet velocity is used to evaluate performances of different strut-cavity configurations and fuel injection patterns. This parameter is a reflection of the contribution of the combustor performance to the engine thrust. The peak of the velocity curve stands for the best performance of the combustor. Then the flowfields are discussed in detail. The flow structures indicate that the injection from the wall behind a strut achieves a great penetration because of the strong upward transport that results from the streamwise vortices behind the strut. Results show that the combustor performance and the flowfields are greatly influenced by the fuel injection patterns. The fuel injections from the strut sides and from the center ring achieve the better performances than that from the wall behind the struts.