Background: To improve droplet deposition rates at the base of rice, an electrical vortex air-assisted spraying system for smalland medium-sized high-clearance boom sprayers was developed. This system uses vortex airflows to guide droplets to the base of rice and the back of leaves, as well as to increase leaf perturbation and droplet penetration and deposition.Results: The spatial distribution of the airflow field generated by this system and the effects of the canopy on the airflow field were described. An orthogonal experiment was performed in a rice field based on fan speed, auxiliary airflow angle, and spray height as the experimental factors. It was discovered that a fan speed of 4000 rpm, auxiliary airflow angle of 0°, and spray height of 30 cm were optimal for droplet deposition at the base of the canopy. These settings resulted in droplet coverage of 54.5% and 35.9% on the front and back of the leaves, respectively, which are 48% and 104% higher than that on the front and back sides of leaves without an auxiliary airflow, respectively. Conclusion: Compared with the traditional application method, vortex air-assisted application significantly improved the rate of droplet coverage in rice canopy of different area. Hence, vortex air-assisted application enables new approaches and methods for rice crop protection.

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The multi-channel air-assisted spraying can distribute air flow according to the crown diameter and be helpful to improve spray deposition and in the reduction of environmental pollution. However, the factors of air flow distribution are not clear. Computational fluid dynamics (CFD) simulation was used in this paper to investigate the influence of the fan speed (600-1800 rpm) and the distance from the air outlet (0-6.0 m) on the airflow field distribution. The measurements and the simulation results were consistent within the boundary of the test range. The results indicated that the airflow field in the central plane was basically axis-symmetric. The airflow field diffused in the central plane at a certain angle of diffusion. The air velocity first increased and then gradually decreased along the central line, and it displayed an exponential function. Within the range of 1.0 m from the air outlet, there was an obvious section of static air between the adjacent air outlets. Beyond this range, the airflow was well-distributed, and the air velocity was normally distributed at the height y. The airfield generated by the multi-channel sprayer was elliptical in its crosssection from the outlet (for x > 1.0 m). The distance of the air supply significantly influenced the fluctuation of the velocity of the airflow, while the speed of the fan had no significant influence on the position of the confluence point of the airflow and the fluctuation of the velocity of each test section.INDEX TERMS Chemical industry, computational fluid dynamics, open area test sites, waste reduction, multi-channel sprayer.

To solve the problem of irrational assignment on the transmission ratio, redesigned the transmission scheme and optimized the parameters of the rice-wheat cyclic planting machine’s ditcher chain transmission device. Results showed that transmission ratio of the improved system was assigned rationally, all the sprockets not only met the strength requirement, but also had moderate sizes and were easy to be assembled or disassembled, at least 41.57% of the material was saved, not less than 50% of the production cost was reduced; noise level of the optimized chain transmission system was lowered obviously than the original’s at the same rotary speeds all the time, the maximum difference reached 16.8 dB when the driving sprockets rotary speeds of the first-stage chain are 1200 rpm; safety of loading, accessibility to field and flexibility of transfer in field of the machine were improved significantly, such an optimized chain transmission system for ditching was reliable.

Enterprises must have business security solutions that provide detection and enforcement at every point of network access. Role-Based Access Control (RBAC) formulates that access decisions are based on the roles that individual users have as members of a system. In RBAC, there are role hierarchies in which a senior role inherits the permissions of a junior role. In order to allow a junior role to perform one or more tasks of a senior role, various delegation models have been proposed in the literature. This paper presents a new role-based delegation model called User-to-Role Delegation Model (URDM), which supports multiple delegation, role hierarchy, and single-step delegation. Four situations are analyzed when URDM runs a multiple delegation process. A web-based system called University Delegation Management System (UDMS) is designed and implemented to verify the core functionality of URDM within the first situation.