scholarly journals Analysis of the Mechanism and Performance Optimization of Burying Weeding with a Self-Propelled Inter Row Weeder for Paddy Field Environments

2021 ◽  
Vol 11 (21) ◽  
pp. 9798
Author(s):  
Han Tang ◽  
Changsu Xu ◽  
Qi Wang ◽  
Wenqi Zhou ◽  
Jinfeng Wang ◽  
...  

To solve the problems of poor quality mechanical weeding and no obvious plowing effect in complex paddy field environments, the burying weeding operation mode was proposed. The height and force acting on the weeds were the main factors that altered the effectiveness of burying. The structure of the rake teeth weeding wheel was designed and matched with appropriate power, and the rake teeth weeding device was optimized. To verify the rationality of the designed device, the forward speed of the machine, rotating speed of the weeding wheels and weeding depth were selected as the experimental factors, and the inter row weeding rate was selected as the experimental index. A quadratic orthogonal rotation combination experiment with three factors and five levels was designed and optimized. The results showed that when the forward speed was 0.64 m/s, the rotational speed of the weeding wheel was 140 r/min, the weeding depth was 56.8 mm, the inter row weeding rate predicted by the model was 88.43%, and the inter row weeding rate was determined by a confirmatory experiment to be 87.06%, which met the weeding requirements for modern agronomy. To intuitively analyze how the soil was disturbed by the weeding wheel, the explicit dynamic analysis software LS-DYNA was used to build a fluid–solid coupling simulation model of the weeding wheel and water soil. The soil density and coupling stress were used to analyze the plowing state of paddy soil when the weeding wheel was operated. This study provides references for the design and development of paddy field weeding components and for mechanical and soil coupling simulation in paddy fields.

Author(s):  
Kui Xu ◽  
Ming Zhang ◽  
Jie Liu ◽  
Nan Sha ◽  
Wei Xie ◽  
...  

Abstract In this paper, we design the simultaneous wireless information and power transfer (SWIPT) protocol for massive multi-input multi-output (mMIMO) system with non-linear energy-harvesting (EH) terminals. In this system, the base station (BS) serves a set of uplink fixed half-duplex (HD) terminals with non-linear energy harvester. Considering the non-linearity of practical energy-harvesting circuits, we adopt the realistic non-linear EH model rather than the idealistic linear EH model. The proposed SWIPT protocol can be divided into two phases. The first phase is designed for terminals EH and downlink training. A beam domain energy beamforming method is employed for the wireless power transmission. In the second phase, the BS forms the two-layer receive beamformers for the reception of signals transmitted by terminals. In order to improve the spectral efficiency (SE) of the system, the BS transmit power- and time-switching ratios are optimized. Simulation results show the superiority of the proposed beam-domain SWIPT protocol on SE performance compared with the conventional mMIMO SWIPT protocols.


Agriculture ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 88
Author(s):  
Mohamed Anwer Abdeen ◽  
Abouelnadar Elsayed Salem ◽  
Guozhong Zhang

Combine harvesters are widely used worldwide in harvesting many crops, and they have many functions that cover the entire harvesting process, such as cutting, threshing, separating, and cleaning. The threshing drum is the core working device of the combine harvester and plays an influential role in rice threshing efficiency, threshing power requirement, and seed loss. In this study, two structures of rice threshers (conical-shaped and cylindrical-shaped) were tested and evaluated for performance under different thresher rotating speeds of 1100, 1300, and 1500 rpm and different feeding rates of 0.8, 1.1, and 1.4 kg/s. The experiment was designed using the Taguchi method, and the obtained results were evaluated using the same technique. The thresher structure and operating parameters were assessed and optimized with reference to threshing efficiency, required power, and productivity. The obtained results revealed that increasing thresher rotating speed and the feeding rate positively related to threshing efficiency, power, and productivity. The highest efficiency of 98% and the maximum productivity of 0.64 kg/s were obtained using the conical-shaped thresher under a 1500 rpm rotating speed and a feed rate of 1.4 kg/s, whereas the minimum required power of 5.45 kW was obtained using the conical thresher under a rotating speed of 1100 rpm and a feed rate of 0.8 kg/s.


2021 ◽  
Vol 13 (12) ◽  
pp. 2342
Author(s):  
Jin-Bong Sung ◽  
Sung-Yong Hong

A new method to design in-orbit synthetic aperture radar operational parameters has been implemented for the Korean Multi-purpose Satellite 6 mission. The implemented method optimizes the pulse repetition frequency when a satellite altitude changes from its nominal one, so it has the advantage that the synthetic aperture radar performances can satisfy the requirements for the in-orbit operation. Other commanding parameters have been designed to conduct trade-off between those parameters. This paper presents the new optimization method to maintain the synthetic aperture radar performances even in the case of an altitude variation. Design methodologies to determine operational parameters, respectively, at nominal altitude and in orbit are presented. In addition, numerical simulation is presented to validate the proposed optimization and the design methodologies.


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