Bio-Adhesives Combined with Lotus Leaf Fiber to Prepare Bio-Composites for Substituting the Plastic Packaging Materials

This work was aim to prepare a packing material from natural resources to reduce the environment pollution caused by plastics.Four bio-adhesives(guar gum,sodium alginate,agar and chitosan)were combined with lotus leaf fibers to prepare degradable composites,respectively.The mechanical properties,moisture absorption profiles and the thermal conductivity of the composites were studied and the cross section morphology and the thermal properties of the composites were analyzed.The Fourier-transform infrared spectroscopy(FTIR)results showed that the polar groups such as–OH and–COO^(–)in bio-adhesives can form hydrogen bond with–OH in lotus leaf fibers to connect the two components.The combination of agar and lotus leaf fiber was good,and their composite had the best mechanical properties,with the tensile strength,flexural strength and impact strength of 2.05,5.9 MPa and 4.29 kJ·m_(−2),respectively,and the composite had a low moisture absorption profile,and the equilibrium moisture absorption rate was 32.32%.The lotus leaf fiber/agar composite(LAC)had an excellent comprehensive performance and it was non-toxic,degradable and thermal insulating,which indicated that it had the potential to use in packaging field to substitute plastics.

Optimized design of the pneumatic precision seed-metering device for carrots

The small size, light weight, irregular shape, and impurities that characterize seed groups increase clogging tendencies in the traditional seed-metering device thereby making it difficult to achieve high-speed precision seeding. A pneumatic seed-metering device with good seed-filling performance for carrot was designed in this study. By analyzing the movement state of seeds in the device under the theoretical condition, it was concluded that the minimum critical negative pressure value of air chamber was 0.32 kPa, which provided a theoretical basis for simulation and testing. ANSYS 17.0 Software was used to simulate the shape of the seeding plate hole. By comparing the pressure, air flow stability between the suction surface and the plug removal surface of the convection field, it was concluded that the conical hole was optimal. A bench verification test was conducted on the device. The average qualified rate, missing rate, and replaying rate were 81.48%, 4.07%, and 14.45%, respectively, which provided a strong reference for the design of carrot precision seed-metering device.

Optimization of a three-row air-suction Brassica chinensis precision metering device based on CFD-DEM coupling simulation

This study aimed to optimize a three-row air-suction Brassica chinensis precision metering device to improve the low seeding performance.ANSYS 17.0 Software was used to analyze the effect of different numbers of suction holes and different suction hole structures on the airflow field.It was found that a suction hole number of 60 was beneficial to the flow field stability and a conical hole structure was beneficial to the adsorption of seeds.Box-Behnken design experiments were carried out with negative pressure,rotational speed,and hole diameter as the experimental factors.The optimal parameter combination was achieved when the negative pressure was 3.96 kPa,the rotational speed of the seeding plate was 1.49 rad/s and the hole diameter was 1.10 mm.The qualification rate of inner,middle,and outer rings were 87.580%,90.548%,and 90.117%,respectively,and the miss seeding rate of inner,middle,and outer rings were 10.915%,7.139%,and 5.920%,respectively.

Optimization of the cylindrical sieves for separating threshed rice mixture using EDEM

The design of the cylindrical sieve equipment used for the screening and separation of agricultural granular materials is mainly through the experimental method,which has the disadvantages of a long development cycle and high cost.To solve this problem,the discrete element method(DEM)was utilized to accurately build the particle models of threshed rice components(grains,shriveled grains,and short stalks),and simulated the separation of grains from the mixture in a cylindrical sieve.The influences of rotational speed(A),cylindrical sieve diameter(B),cylindrical sieve aperture(C),and inclinational angle(D)on screening cleaning rate,screening loss rate,and screening efficiency were investigated.Meanwhile,the optimal parameters of the cylindrical sieve were obtained using a central composite design(CCD)under response surface methodology(RSM).The results of CCD showed that the quadratic multinomial model is credible and revealed that the cylindrical sieve aperture has a significant impact on the screening characteristics.It is predicted that the optimal values for screening cleaning rate,loss rate,and efficiency were 97.84%,0.27%,and 85.38%,respectively,while A,B,C,and D were 23.6 r/min,297 mm,8.7 mm,and 2°,respectively.The experimental results using a real threshed rice mixture were found to be in good agreement with the optimal simulation results.This study proved a reliable research method and provides a design reference for the cylinder sieving systems for threshed rice or separation of other bulk material.

Review of agricultural IoT technology

Agricultural Internet of Things(IoT)has brought new changes to agricultural production.It not only increases agricultural output but can also effectively improve the quality of agricultural products,reduce labor costs,increase farmers'income,and truly realize agricultural modernization and intelligence.This paper systematically summarizes the research status of agricultural IoT.Firstly,the current situation of agricultural IoT is illustrated and its system architecture is summarized.Then,the five key technologies of agricultural IoT are discussed in detail.Next,applications of agricultural IoT in five representative fields are introduced.Finally,the problems existing in agricultural IoT are analyzed and a forecast is given of the future development of agricultural IoT.