Study of Groove Parameters on the Hydrodynamic Behavior of Spiral-Grooved Thrust Bearing with Gas Lubricant

The gas-lubricated thrust bearing is widely used in agriculture mechanical systems, and the groove shape plays an important role on the hydrodynamic behavior of spiral-grooved thrust bearing (SGTB). Although the groove shape may change smaller, it is clear that the hydrodynamic response is very sensitive to the groove parameters. This paper proposes a computational method for the analysis of SGTB with gas lubricant, considering the effects of groove parameters. With the compressibility taken into account, the evaluation of lubrication performance for SGTB is obtained by the CFD technology. Also, the simulation results are compared with the published data, which indicates that the presented model of SGTB is able to obtain more realistic results of hydrodynamic characteristics of SGTB. Moreover, the mapping relationship between groove parameter and hydrodynamic behavior of SGTB is represented

Research on the Smart Broad Bean Harvesting System and the Self-Adaptive Control Method Based on CPS Technologies

With the rapid development of new-generation cyber–physical system (CPS) technologies, the smart operation and management of the broad bean harvesting system are enabled. This paper proposed a smart broad bean harvesting system (SBHS) and a self-adaptive control method based on CPS technologies. Firstly, the overall architecture of the SBHS is designed, which consists of four main components, namely optimal intelligent perception environment configuration, digital twin model construction, virtual simulation and real-time optimization, self-adaptive adjustment and control. Then, three key enabling technologies are discussed in detail, namely, intelligent perception environment configuration for the SBHS, digital twin model construction for the SBHS, colored Petri net (CPN)-based self-adaptive analysis and control of the harvesting system. Lastly, a proof-of-concept experiment based on a cooperative company is presented to illustrate the main work logic and advantage of the proposed SBHS. After the edge–cloud cooperative intelligent harvesting environment is configured, the CPN model for the workflow of the SBHS is created to analyze and optimize the harvesting processes. In addition, a management and control platform are developed to further illustrate the implementation of the proposed SBHS and the self-adaptive control method

Design and trial-produce of a special nail-tooth thresher for pulses crops

Pulses crops are widely distributed in China, but mechanization production-level of this crops is relatively low at present. So, a special nail-tooth thresher for pulses crops was carried out in this project to solve the problem of mechanical threshing. The roller diameter, speed, length, and nail-tooth structure, stripper concave screen, power device and cleaning system are determined by detailed theoretical calculation. Testing result of the trial-production prototype showed that the threshing roller with large diameter and low rotating speed, the nail-tooth threshing mechanism and the concave plate screen with large spacing are suitable for the broad bean thresher. The optimal combination is roller speed 400 /min, feed quantity 1.2 kg/s and concave tolerance 54 mm. Testing results showed that impurity content and breaking rate of the developed nail-tooth type broad bean thresher were respectively 1.09 %and 3.45%, It could improve the efficiency of the pulses crops threshing process significantly

Design and trial-produce of a special nail-tooth thresher for pulses crops

Pulses crops are widely distributed in China, but mechanization production-level of this crops is relatively low at present. So, a special nail-tooth thresher for pulses crops was carried out in this project to solve the problem of mechanical threshing. The roller diameter, speed, length, and nail-tooth structure, stripper concave screen, power device and cleaning system are determined by detailed theoretical calculation. Testing result of the trial-production prototype showed that the threshing roller with large diameter and low rotating speed, the nail-tooth threshing mechanism and the concave plate screen with large spacing are suitable for the broad bean thresher. The optimal combination is roller speed 400 /min, feed quantity 1.2 kg/s and concave tolerance 54 mm. Testing results showed that impurity content and breaking rate of the developed nail-tooth type broad bean thresher were respectively 1.09 %and 3.45%, It could improve the efficiency of the pulses crops threshing process significantly

Enhancement thermal stability and CO2 adsorption property of ZIF-8 by pre-modification with polyaniline

In this study, the thermal stability and CO _2 adsorption property of ZIF-8 were effectively improved by using parallel flow-drop solvothermal method. -NH _2 was successfully introduced into the surface of ZIF-8 and their structures by pre-modification with polyaniline. XRD analysis shown that the intensity of ZIF-8 characteristic peak increased with the increase doped content of polyaniline, but the crystal structure of ZIF-8 remained unchanged. FTIR analysis shown that the two new peaks at 1609 and 690 cm ^−1 can be attributed to the -NH _2 bonding of ZIF-8. TGA analysis shown that the thermal stability of NH _2 -ZIF-8 was 632.71 °C. SEM analysis shown that the increase of CO _2 adsorption property was due to the increase of NH _2 -ZIF-8 cubic crystal system. It was found that BET surface area was 789.7 m ^2 g ^−1 , micropore volume was 0.55 cm ^3 g ^−1 , pore size was 0.99 nm by taking the molar ratio of metal ions to ligands being 1:2, and the molar ratios of polyaniline to metal ions being 12%

Study on the structure activity relationship of the crystal MOF-5 synthesis, thermal stability and N2 adsorption property

The parallel flow drop solvothermal method was utilized to synthesize the crystal of MOF-5 by taking the molar ratio of the metal ions to the organic ligands of 2:1 at 140∘C, and the reaction time at 12 hours. Meanwhile, the structure and properties of MOF-5 were characterized by the X-ray diffraction (XRD), scanning electron microscope (SEM), thermogravimetric analysis (TGA) and fourier transform infrared spectroscopy (FTIR). SEM analysis shown that the crystal morphology of MOF-5 changed from sheet to cubic with increasing reaction temperature and molar ratio of the metal ions to the organic ligands, and its thermal stability was also gradually increased. TGA analysis shown that its thermal stability could live up to 489.36∘C. FTIR analysis shown that the terephthalic acid is completely protonated, and the Zn2+ and the carboxyl group are formed by the coordination of the multi-tooth bridge in the crystal of MOF-5. Then the structure activity relationship of the crystal MOF-5 synthesis, microstructural, thermal stability and N2 adsorption property were further studied

Control of soil organic carbon under karst landforms: A case study of Guizhou Province, in southwest China

Global karst landforms account for about 15 % of the land area. The development of karst landforms in southwest China accounts for>1/3 of the country's land area, and is considered to be an important carbon storage with considerable carbon sequestration potential to alleviate global warming. Clarifying the response mechanism of soil organic carbon (SOC) to different controlling factors is of great significance to formulate and implement regional carbon sink strategies. Based on 517 soil samples in Guizhou Province, this study used geostatistical methods to analyze the spatial heterogeneity of SOC in Guizhou Province. The effects of altitude, land use, soil type, slope direction, slope position, slope gradient and rock exposure rate on the spatial variability of SOC in karst areas were quantitatively compared by statistical analysis methods. The results showed that the mean value of SOC content in Guizhou Province was 19.59 g/kg, and the coefficient of variation was 69.11 %, showing moderate-intensity variation. Spatially, the SOC content in Guizhou Province showed a declining trend from west to east, with the low-value areas predominantly distributed in the south and north areas. The semi-variogram model showed that the nugget coefficient C0/(C0 + C) was  slope gradient (0.255) > rock exposure rate (0.166) > land use (0.08) > slope position (0.059) > slope direction (0.043) > soil type (0.041). This research suggests that the provincial government should pay attention to the control of rocky desertification and the development of modern low-carbon agriculture in the work of increasing soil carbon sequestration

Economic Assessment of Food Legumes Breeding in China: Evidence Using a Provincial Level Dataset

Advances in crop breeding techniques and economic evaluation are critical to ensuring and improving crop yields and sustainable development. Based on the provincial data on food legumes breeding (FLB) in China from 2001 to 2020, the research and development (R&D) expenditure distribution, FLB contribution rate, and R&D expenditure on FLB were estimated. The economic benefits of output per unit area and R&D expenses were evaluated, and relevant policy suggestions were put forward. The study found that: (i) the R&D expenditure on FLB’s showed a significant upward trend, and the development can be divided into a starting, stable, and rapid growth period. There were significant differences in R&D expenditures across eight provinces of China with relatively high R&D expenditures for FLB; (ii) the R&D expenditure on FLB had a significant lag in the improvement of per mu yield (1 mu = 0.067 hectares). For every 10,000 yuan increase in R&D funding for FLB, the yield per mu will increase by 0.145 kg/mu in the next five years, and the regional spillover effect of breeding costs is significant; and (iii) the marginal revenue of R&D expenditures FLB from 2008 to 2020 is 34.91 yuan, that is, every 1 yuan invested in breeding R&D can bring a short-term marginal revenue of 34.91 yuan and a long-term marginal revenue of 337.23 yuan. Based on the above analysis, some recommendations were proposed and discussed, including further increasing the R&D investment of FLB, strengthening industry–university–research cooperation in breeding, improving the breeding research system, and promoting the multi-dimensional development of FLB industry–university–research services