The effect of different content (0–20 wt%) Acrylonitrile-styrene-acrylic (ASA) on mechanical, thermal and three-body wear behaviors of eucalyptus fiber/polyvinyl chloride (EF/PVC) composites were studied in this research. The results show that the mechanical properties of the composites such as impact strength, tensile strength, flexural strength and flexural modulus increased with increasing ASA content lower than 15 wt%. The addition of 15 wt% and 20 wt% ASA can improve thermal stability of the EF/PVC composites in the early period of the heating, and the effect weakened on later stage due to the thermal degradation of ASA, which occurred in the temperature range 416°C–442°C. The three-body wear resistance of the EF/PVC composites can be improved by ASA, and the abrasive wear mechanism of the composites was predominated by linear travel, sand particle plough and cut action, ASA and PVC plastic deformation, and fibers debonding.
Wood-plastic composites are being widely used more and more, and the bonding strength between fillers and matrix is an important factor affecting the properties of wood-plastic composites. In this study, rapeseed straw and rapeseed stalk were pretreated with sodium hydroxide and then filled with polyvinyl chloride matrix to prepare composites. The chemical composition, thermal stability, microstructure, physical properties, mechanical properties, and abrasive wear resistance of the composites were characterized, and the effects of different concentrations of alkaline treatment on rapeseed straw composite and rapeseed stalk composite were revealed. The results show that alkaline treatment has no significant effect on the chemical composition of the composites but has an obvious effect on other properties. Among them, after 1% alkaline treatment, rapeseed straw composite has the highest hardness, thermal stability, and impact strength, rapeseed stalk composite has the highest impact strength and bending strength. After 3% alkaline treatment, rapeseed straw composite has more wear resistance, rapeseed stalk composite has the highest density, the highest tensile strength, and more wear resistance. The rapeseed straw composite with 5% alkaline treatment has the highest density, and the rapeseed stalk composite with 7% alkaline treatment has the highest thermal stability. The hardness of rapeseed stalk composite and the tensile strength and bending strength of rapeseed straw composite decreased with the increase of alkaline treatment concentration.
The effects of ultrasonic and hydrothermal treatment on the physical, mechanical, wear resistance, water absorption and thermal stability of the walnut shell (WS)/attapulgite (ATP)/polyvinyl chloride (PVC) composite and its enhancement mechanism were investigated. WS was treated by ultrasound and hydrothermal treatment and mixed with PVC and ATP, and the WS/ATP/PVC composites were prepared by melt extrusion. The properties of composites were characterized, and the results showed that after ultrasonic and hydrothermal treatment, the main chemical structure of composites was not changed significantly. Compared with untreated composites, the wear resistance after ultrasonic treatment for 10 min is the best. After ultrasonic treatment for 15 min, the bending strength, tensile strength and impact strength of the composite are increased by 8.9%, 10.3% and 46.2%, respectively. Hydrothermal treatment at appropriate temperatures also improved some properties of the composites. The composites after hydrothermal treatment at 110°C had the best thermal stability and highest hardness, and the bending strength and tensile strength values were increased by 5.9% and 5.2%, respectively. The impact strength of the composite increased with the increase of hydrothermal treatment temperature. The results showed that ultrasonic and hydrothermal treatments have the potential to improve the performance of wood–plastic composites as environmentally friendly pretreatment methods.
The emergence of power dispatching automation systems has greatly improved the efficiency of power industry operations and promoted the rapid development of the power industry. However, with the convergence and increase in power data flow, the data dispatching network and the main station dispatching automation system have encountered substantial pressure. Therefore, the method of online data resolution and rapid problem identification of dispatching automation systems has been widely investigated. In this paper, we perform a comprehensive review of automated dispatching of massive dispatching data from the perspective of intelligent identification, discuss unresolved research issues and outline future directions in this area. In particular, we divide intelligent identification over power big data into data acquisition and storage processes, anomaly detection and fault discrimination processes, and fault tracing for dispatching operations during communication. A detailed survey of the solutions to the challenges in intelligent identification over power big data is then presented. Moreover, opportunities and future directions are outlined.
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