Traditional static anaerobic digestion technology presents the disadvantages of a low gas production rate and long digestion cycle, which is not conducive to the treatment of livestock manure. A 12 m³ multiphase flow anaerobic digester (MFD) was developed in this study to improve the biogas production rate and maintain constant temperature digestion during winters. Full-scale field experiments were conducted on the biogas production rate at different temperatures, the dynamic digestion effects, and the dynamic heating digestion effects of the system at Sichuan, China. A comparison of the dynamic and static digestion results of 50 days indicated that the biogas production for the dynamic digestion (DD) group was 115.22 m³ or 127.1% higher than that of the static digestion (SD) group with the same digestion temperature. The results of the heat transfer performance experiment revealed that the heat transfer rate of the system increased significantly, and the temperature of the biogas slurry increased rapidly. The optimization analysis of the system was based on the experimental results of the relationship between the slurry temperature and biogas production rate, and the economical digestion temperature of the system was proposed and calculated. Different insulation materials or insulation thicknesses have an influence on the economical digestion temperature. Additionally, the economical digestion temperature of the system in which the polystyrene insulation layer with a thickness of 90 mm was used, was found to be 27.2 °C. When digestion temperature was 22.3 °C, the energy efficiency ratio (EER) of dynamic anaerobic digestion system is 1. The advantages of MFD are low biogas production unit cost and high heat and mass transfer rate. However, the disadvantage of high operation energy consumption needs further improvement. And additional energy was required when system digestion temperature below 22.3 °C. The proposed MFD and dynamic anaerobic digestion system can play a significant role in using biomass resources and promoting the development of biogas projects.

Dynamic modelling method for disc indexing cam mechanism was presented based on virtual prototype technology according to the analysis of mechanism feature. Rigid-flexible coupled dynamic model was established by means of Adams, Pro/E and Ansys softwares. Dynamic simulation has been done. It follows the analysis of simulation that effects of input speed, and stroke angle to torsional vibration were illustrated corresponding to dynamics simulation. Dynamic characteristics of different transmission functions commonly used in practical engineering were analyzed in detail. The application principle of transmission functions was presented based on dynamic simulation and analysis results. Construction method of transmission function was presented finally.

The traditional biogas heating system has the disadvantages of a low energy efficiency ratio and high energy consumption. In this study, a solar-untreated sewage source heat pump system (SUSSHPS) was developed for heating a 12 m³ multiphase flow digester (MFD) in Suining, China. To investigate the operating effects, two modes were defined according to the solar fractions in different regions. On the basis of experimental data, thermodynamic calculations and operating simulation analysis were performed, and the solar collector area (Ac) and the minimum length of the sewage double-pipe heat exchanger (lmin) for the two modes were calculated. The results indicated that the Ac and lmin of mode 2 were larger than those of mode 1 at different solar fractions. Additionally, the results suggested that mode 1 can be used at a solar fraction of 0.5. Moreover, a comprehensive evaluation of different biogas heating systems was performed. Two evaluation methods were used for modeling calculations, and the results of the two methods were consistent. The SUSSHPS had the largest comprehensive evaluation value among the four systems. The proposed SUSSHPS can play a significant role in improving current biogas heating systems and promoting the development of biogas projects.

Summarized the research and development of high speed machining of SiCp/Al composites. Emphasized the research status of high speed cutting of SiCp/Al composite materials, including machined surface quality and tool wear condition. Machined surface quality contains surface roughness and surface defects. The tool wear conditions are different because of different types of cutting tools, but the wear of the rake face, the rear face and the cutting edge are all involved.