Modeling and assessing the sustainability of machining systems has been considered to be a crucial approach to improving the environmental performance of machining processes. As the most common machining system, the computer numerical control (CNC) milling system is a typical man–machine cooperative system where the activities of the machine tool and operator generate material and energy consumption. However, the energy consumption of the operator in the CNC milling system has often been ignored in most existing research. Therefore, existing methods fail to provide a comprehensive understanding of the sustainability of the CNC milling system. To fill this gap, an exergy loss assessment method is proposed to investigate the sustainability of the CNC milling system, where the energy consumption of the operator, the energy consumption of the machine tool, and material consumption are taken into consideration. The key performance indexes of the energy consumption of the operator, the energy consumption of the machine tool, the exergy loss, and the specific exergy loss (SEL) are analyzed and modeled. To demonstrate the feasibility of the proposed method, a case study was carried out on a three-axis machining center (XH714D), in which the energy consumption of the operator, the energy consumption of the machine tool, the exergy loss of energy consumption, the exergy loss of chips, the exergy loss of compressed air, the exergy loss of cutting tool wear, the exergy loss of cooling liquid dissipation, and the SEL were found to be 169,750 J, 758,211 J, 603,131 J, 2,031,404 J, 22,023 J, 301,868 J, 2673 J, and 88.04 J/mm³, respectively. The proposed method is effective to assess the sustainability of the CNC milling system, and the established exergy loss models build a good basis for exergy efficiency optimization.

Based on the polyvalent characteristics and excellent catalytic performances of manganese and vanadium, potentiometric gas sensor using MnV ₂ O ₆ sensing electrode was fabricated for NH ₃ detection at high temperatures. NH ₃ sensitivity of the sensors sintered at 700 °C, 750 °C and 800 °C were −52.4, −60.0 and −39.1 mV/decade respectively, and the detection limit reaches 2 ppm at 550 °C. 700 °C-sintered sensor displays the slowest response rate, and sample sintered at 800 °C shows the lowest and unstable responses. Excessive temperature promotes the destruction of electrode microstructure, thus leads to the deterioration of sensor’s sensitivity. For NH ₃ below 40 ppm, sensor attached with MnV ₂ O ₆ electrode has the highest responses and slowest recovery rate at operating temperature of 500 °C, and presents the lowest signal and fastest recovery at 600 °C. 550 °C is considered the optimal operating temperature based on high sensitivity and shortest response time. Cross sensitivity of MnV ₂ O ₆ to other oxidizing/reducing gases is much lower than NH ₃ , and it shows good anti-interference ability to oxygen/vapor content change in certain range. Polarization curve showed that the reason for high NH ₃ selectivity was mainly due to high electrochemical catalytic activity of MnV ₂ O ₆ to NH ₃ , and electrochemical impedance spectroscopy test proved that sensing electrode played a leading role compared with reference electrode in response process.

Considering that consumers are more willing to buy products online, companies are increasingly selling remanufactured products online through e-commerce platforms. Notwithstanding the high attention it elicits from researchers and companies, the current study on the remanufacturing trading platform is still in its infancy. Thus, we investigate 20 remanufacturing trading platforms and make a gap analysis among them in terms of (i) business model, (ii) product display, (iii) delivery products, (iv) quality assurance and after-sales service, (v) product review and star rate, and (vi) transaction and payment. On this basis, we analyze features for the development of remanufacturing trading platforms and propose six key applications aimed at filling the identified gaps. The consortium blockchain has the characteristics of security and transparency, high credibility, traceability and unfalsifiability, low cost, and strong scalability, which can provide effective support for the six key applications. Then, we construct the technical framework and the model of a consortium blockchain-supported remanufacturing trading platform. Further, we analyze the coupling mechanism between the consortium blockchain and the remanufacturing trading platform to explain how the remanufacturing trading platform supported by the consortium blockchain achieves the development characteristics. This study provides important guidance for the development, construction, and operation management of remanufacturing trading platforms.

Modeling and assessing the sustainability of machining systems has been considered to be a crucial approach to improving the environmental performance of the machining processes. As the most common machining system, the computer numerical control (CNC) milling system is a typical man-machine cooperative system where the activities of the machine tool and operator generate material and energy consumption. However, the energy consumption of the operator in the CNC milling system has often been ignored in most existing research. Therefore, existing methods fail to provide a comprehensive understanding of the sustainability of the CNC milling system. To fill this gap, an exergy loss assessment method is proposed to investigate the sustainability of the CNC milling system, where the energy consumption of the operator, the energy consumption of the machine tool, and material consumption are taken into consideration. The key performance indexes of the energy consumption of the operator, the energy consumption of the machine tool, the exergy loss, and the specific exergy loss (SEL) are analyzed and modeled. To demonstrate the feasibility of the proposed method, a case study was carried out on a three-axis machining center (XH714D), in which SEL was found to be 88.04J/mm3. The proposed method is effective to assess the sustainability of the CNC milling system, and the established exergy loss models build a good basis for exergy efficiency optimization.

Considering that consumers are more willing to buy products online, companies are increasingly selling remanufactured products online through e-commerce platforms. Notwithstanding the high attention it elicits from researchers and companies, the study about the remanufacturing trading platform is in its infancy. Thus, we investigate 20 remanufacturing trading platforms related nowadays and make a gap analysis among them in terms of: (i) business model, (ii) product display, (iii) delivery products, (iv) quality assurance and after-sales service, (v) product review and star rate and (vi) transaction and payment. On this basis, we analyze features and trends for the development of remanufacturing trading platforms and propose six key applications aimed at filling the identified gaps. The consortium blockchain has the characteristics of security and transparency, high credibility, traceability and unfalsifiability, low cost, and strong scalability, which can provide effective support for the six key applications. Then, we construct the technical framework and the model of a consortium blockchain-supported remanufacturing trading platform. Further, we analyze the coupling mechanism between consortium blockchain and remanufacturing trading platform to explain how the remanufacturing trading platform supported by consortium blockchain achieves development characteristics. This study provides important guidance for the development, construction, and operation management of remanufacturing trading platforms.

To improve the traditional method of teaching paths for industrial robots, a path planning method using the repulsive force field of artificial potential field method is proposed to improve the A* algorithm in space to plan a moving path with high security. Extending the A* algorithm to space for global search, adding repulsive influence factors, improving the cost function, modifying the cost of moving the end of the manipulator near the obstacle, and improving the path safety. Comparing the performance of the traditional A* algorithm, Artificial Potential Field(APF) method and improved algorithm in the same environment, the improved algorithm has significantly improved in path security.