The widespread use of petroleum-based products has led to increasing environmental and ecological problems, while the extraction and application of various natural cellulose fibers have received increasing attention. This research focuses on the extraction of cellulose fibers from cow dung using different treatments: hot water, hydrogen peroxide (H₂O₂), sodium hydroxide (NaOH) and potassium hydroxide (KOH) boilings, as well as a selection of the best quality cow dung fibers for papermaking with quality control. The study’s objective is to find a sustainable method to extract as much material as possible from renewable biomass feedstock. The results show that the best extraction rate is obtained by KOH boiling with 42% cellulose fibers extracted. Corresponding handmade paper has a burst index of 2.48 KPam²/g, a tear index of 4.83 mNm²/g and a tensile index of 26.72 Nm/g. This project expands the sources of natural cellulose fibers to an eco-friendly and sustainable one and opens up new applications for cow dung.

Biodegradable paper mulch has the advantages of being easily degradable and environmentally benign, but its own performance and adaptability to harsh environments have not been tested. This paper uses scanning electron microscopy and three-dimensional morphometry to microscopically characterize biodegradable paper mulch and white plastic mulch. To analyze and compare their mechanical and hydrophobic properties, and weather resistance, the two mulches were measured through tensile tear load and static contact angle. A comparative analysis of the effect of mulching in the dry crop area of the Hexi Corridor was conducted by comparing the growth index, farm water heat, soil oxygen content, and yield using maize and flax. The test results show that biodegradable paper mulch films were slightly inferior to traditional white mulch films in terms of mechanical and hydrophobic properties, with inadequate insulation and moisture retention, but better in terms of aging resistance, soil oxygen content, and crop insulation and water storage capacity in the middle and growth stages. White mulch film had a better yield enhancement effect on maize, while with biodegradable paper mulch film, this was more significant with flax.

Determination of the coefficient of rolling friction of irregularly shaped maize particles by using discrete element method

Mechanization of field experiments is the only way to improve crop breeding and seed propagation effects. In order to further clarify and improve the working performance of tapered threshing device for plot breeding, and reduce the remaining seeds in the device, the numerical simulation was carried out on the motion process of materials in the longitudinal-axial tapered cylinder threshing and transmission device of the plot wheat breeding combine harvester based on CFD-DEM method. Simulation results showed that, threshing and transmission of particles and short stalks at axial direction could be realized under the influence of air flow. Meanwhile, the material transference and distribution rule and stream field distribution rule of air flow in the threshing and transmission device were obtained, the variations of velocity and displacement of particles and short stalks with time were obtained; the motion trajectories and forms of particles in different types of retention were also studied. At rotating speed of 1300-1600 r/min for the tapered threshing cylinder in the verification test, the particle retention rate in the enclosure was 0-0.13%, while in the simulation the particle retention rate in the enclosure was 0-0.11%, only a 0.02% difference between them. The results proved a favorable feasibility to simulate the working performance of the tapered threshing and transmission device for plot breeding through gas-solid coupling method. Keywords: particle threshing and transmission, tapered threshing and transmission device, hydromechanics calculation, discrete element, numerical simulation, test DOI: 10.25165/j.ijabe.20191201.4458 Citation: Dai F, Song X F, Zhao W Y, Han Z S, Zhang F W, Zhang S L. Motion simulation and test on threshed grains in tapered threshing and transmission device for plot wheat breeding based on CFD-DEM. Int J Agric & Biol Eng, 2019; 12(1): 66–73.

Autonomous navigation for agricultural machinery has broad and promising development prospects. Kalman filter technology, which can improve positioning accuracy, is widely used in navigation systems in different fields. However, there has not been much research performed into navigation for sprinkler irrigation machines (SIMs). In this paper, firstly, a self-developed SIM is introduced. Secondly, the kinematics model is established on the platform of the self-developed SIM, and the updated Sage–Husa adaptive Kalman filter, which is an accurate and real-time self-adaptive filtering algorithm, is applied in the navigation of the SIM with the aim of improving the positioning accuracy. Finally, experiment verifications were carried out, and the results show that the self-developed SIM has good navigation performance. Besides this, the influence of abnormal observations on the positioning accuracy of the system can be restrained by using the updated Sage–Husa adaptive Kalman filter. After using the updated Sage–Husa adaptive Kalman filter for the SIM, the maximum deviation between the SIM and the predetermined path is 0.18 m, and the average deviation is 0.08 m; these deviations are within a reasonable range. This proves that the updated Sage–Husa adaptive Kalman filter is applicable for the navigation of sprinkler irrigation machines.

The shape of corn seeds not being spherical affects their mobility. This study focuses on modeling the typically shaped corn seeds and calibrating the coefficient of rolling friction for different shape types to improve simulation reliability. By analyzing the corn seed shape characteristics and size statistics, this study establishes a classification system that enables the determination of the average value and quantity of different types of corn seed using the spherical granule cluster method. The discrete element method is used to model simplified corn models, and contact parameters are validated through two types of repose angle and a seed metering experiment. In the collapse repose experiment, the relative error between the simulation and the experiment was only 0.72%, while the relative error in another repose experiment was 0.2%. The verification experiment for the metering of seeds showed that the relative error between the simulation and the experiment was below 15% at both low and high speeds, and the multi-grain rate error was less than 10%. This shows that the method proposed in this paper is somewhat accurate.