Design and Test of a Jet Remote Control Spraying Machine for Orchards

Aimed at issues associated with the poor air supply and poor automatic targeting accuracy of existing orchard sprayers, this paper designs a jet-type orchard remote control sprayer with automatic targeting which is suitable for standardized orchards in hilly and mountainous areas. By optimizing the structure of the diversion box, the uniformity of deposition and penetration ability of the pesticide droplets to the fruit tree canopy are improved, and a uniform wild field distribution is realized simultaneously. An accurate positioning of the fruit tree canopy space orientation is achieved through automatic targeting and azimuthal adjustment systems. When the target is detected, the solenoid valve is controlled to open, and vice versa, and the distance from the nozzle to the fruit tree canopy is adjusted in real time to improve the utilization rate of pesticides. The test results show that the effective range of the jet-type orchard remote control sprayer is no more than 3.5 m, and the maximum flow rate range is 6~6.5 L/min. Within the effective spraying range, the farther the distance is, the higher the automatic targeting accuracy. The pesticide droplets sprayed by the spraying machine have a certain penetration ability, and the uniformity of the droplets is good, which solves solidification problems caused by the penetration of pesticide into the soil. This research provides a reference for jet spraying operation and automatic targeting spraying structure design

Design and Test of Stripping and Impurity Removal Device for Spring-Tooth Residual Plastic Film Collector

The residual agricultural plastic film in China is not easily recovered due to the thinness and poor mechanical properties of domestic films, and a large amount of plastic film remaining in farmland soil poses a great threat to soil quality and crop production. A spring-tooth residual plastic film collector (SRPFC) is widely used in domestic residual plastic film (RPF) recycling operations. However, there are two major problems in the current SRPFC: the low recovery rate of the residual film (RRRF) caused by the difficulty of film-stripping and the high impurity rate in the film (IRF). In this paper, a stripping and impurity removal device (SIRD) is designed to address the existing problems of SRPFC, which is mainly composed of film-stripping tooth plates (FTP), two wind-collecting hoods, and two centrifugal fans. The motion and force analysis of the RPF in the film-stripping process was carried out, and the arc FTP was determined to be used for film-stripping. The size parameters of the FTP were obtained by establishing the coordinate system to solve the differential equation. By comparing and analyzing the force of RPF in the airflow field of the test bench for suspension speed and the airflow field of the wind-collecting hood, the RPF equivalent particle was established. The discrete phase model (DPM) in Fluent software was used to simulate the movement of the RPF equivalent particle, and the calculated air volume range of the centrifugal fan was 5501.88~6829.92 m3/h. The effects of forward speed, rotating speed of film conveying chain harrow (FCCH), and rotating speed of the centrifugal fan on RRRF and IRF were studied by orthogonal rotary combination experiment. The test results showed that the best combination of machine operation parameters was when the forward speed was 5 km/h, the rotating speed of the FCCH was 235 r/min, and the rotating speed of the centrifugal fan was 1978 r/min. Under these conditions, the RRRF was 92.53%, and the IRF was 9.31%. Field experiments were carried out with the rounded parameters, and the average RRRF was 92.07%, and the average IRF was 9.56% under the parameter combination, indicating that the optimization scheme of the device was feasible

Analysis and Optimization Test of the Peanut Seeding Process with an Air-Suction Roller Dibbler

The air-suction roller dibbler for peanuts is the core component to realizing precision seeding on film; however, the seeds in the dibbler cannot accurately fall into the seed-guiding mechanism during the work. In this study, we stabilized the seed trajectory by adjusting the installation angles of the chock block (IACB) and installation angles of the dibbler cover (IADC). We studied the seed-movement characteristics under different IACB and dibbler covers using EDEM simulation software. The separation between the seed and the baffle was obtained for different installation conditions, which were contact separation and noncontact separation. We obtained the best seeding performance when the seed was released from the edge of the dibbler cover in contact with the baffle of the seed separation tray. In the bench test, we obtained the best seed-feeding performance at 48.28° for the IACB, 12.29° for the IADC, and 3.84 km/h for the machine. The seeding pass rate was 95.35%, the missed seeding rate was 2.52%, and the reseeding rate was 2.11%. The field verification test showed that the machine worked well with the combination, and the seeding pass rate was above 92%, which meets the requirements of the single-grain precision sowing of peanuts and substantially improves the operation performance

Optimization of Screen-Hole-Clearing Devices for Mechanized Residual Film–Impurity Separation

The airflow velocity in some nozzles is low, and the clearing of the nozzle is ineffective because of unreasonable airflow pipe arrangements and the distance from the nozzle to the screen surface of screen-hole-clearing devices for trommel-sieve-type residual film–impurity wind separators. In the present study, the main structure and working parameters affecting the screen hole clogging situation were determined through theoretical analysis and computational fluid dynamics simulations. In addition, a three-factor, three-level quadratic regression orthogonal center of rotation combination test was performed. The distance from the nozzle to the screen surface, fan wind speed, and the number of airflow pipes were selected as test factors, and the ratio of impurities in the residual film and the blockage ratio of the screen holes were selected as the evaluation indexes. The results indicated that the ratio of impurities in the residual film was reduced by 2.42% and the blockage ratio of the screen holes was reduced by 1.92% at a nozzle-to-screen distance of 102 mm, a fan wind speed of 24 m/s, and with four air pipes. The resulting impurity ratio in the film was 5.86%, and the blockage ratio of screen pores was 5.41%. The minimum airflow velocity of 15.8 m/s at each nozzle position of the optimized screen-hole-clearing device satisfied the requirements of screen hole clearing and blockage. Furthermore, the ratio of impurities in the residual film and the blockage ratio of the screen holes remained unchanged during the continuous operation of the device. This indicated that the optimized screen-hole-clearing device had a stable working performance. This study may provide a theoretical framework for the future development of screen-hole--clearing devices

Intravenous thrombolysis in acute ischemic stroke patients with pre‐stroke disability: A systematic review and meta‐analysis

Abstract Background Intravenous thrombolysis (IVT), which is safe and effective, is the first‐line therapy for acute ischemic stroke (AIS). However, its benefit for AIS patients with pre‐stroke disability (PSD) is controversial. Objective We determined the association of PSD with the safety and efficacy of IVT among patients with AIS. Methods We searched PubMed, Embase, and the Cochrane Library from inception to May 23, 2022. The articles focusing on outcomes of AIS patients with PSD receiving IVT were retrieved. We used the random‐effects model to pool outcomes including mortality, 24 h NIHSS improvement, symptomatic intracerebral hemorrhage (sICH), favorable functional outcome (FFO), the favorable outcome, and mortality prevalence. Results Ten studies (including 245,773 participants) that reported the outcomes of AIS patients with PSD undergoing IVT were included. In unadjusted analyses, PSD was associated with mortality (10 studies; odds ratio [OR] 1.739, 95% confidence interval [CI], 1.336–2.407), FFO (7 studies; OR 1.057, 95% CI, 1.015–1.100), 24 h NIHSS improvement (5 studies; OR .840, 95% CI, .819–.917, p = .000), and sICH (9 studies; OR .773, 95% CI, .481–1.243). In adjusted analyses, PSD was associated with mortality (seven studies; ORadj 1.789, 95% CI, 1.413–2.264), FFO (five studies; ORadj 1.087, 95% CI, 1.002–1.179), 24 h NIHSS improvement (five studies; ORadj .837, 95% CI, .799–.876), and sICH (five studies; ORadj .857, 95% CI, .725–1.012). The prevalence of FFO and mortality in patients with pre‐stroke modified Rankin Scale scores of 2–5 were 49% (0.42–0.56) and 37% (0.21–0.53), respectively. Conclusions Patients with PSD undergoing IVT had a higher mortality rate than those without PSD. Meanwhile, PSD was associated with FFO, and there was no significant difference in sICH and 24 h NIHSS improvement. High‐quality data are needed to clarify the benefits of administering IVT in these patients