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Facing the development trend of electrification of construction machinery, in view of the drawbacks of the existing electro-hydraulic-load-sensitive system in terms of dynamic characteristics and usage of energy, based on the drive source of a servo motor-driven quantitative pump, an electro-hydraulic-load-sensitive system on the basis of torque open-loop control was proposed. Firstly, the working principle of the system was introduced and the system's operating characteristics and energy consumption characteristics were theoretically analyzed. Secondly, in order to balance the system's energy usage and maneuverability, a control strategy with a variable pressure margin was designed. Meanwhile, in order to solve the problem that the hydraulic pump's mechanical efficiency causes system pressure control deviation, a torque compensation method based on offline data and speed prediction was proposed. Finally, simulation and testing were used to confirm the viability of the control strategy. The test results show that: the system could realize stable pressure margin control, and the response rise time was within 0.7 s under a variety of flow circumstances; the system could follow the control instruction to change linearly and the flow rate changed smoothly in the adjustable pressure gap control; after using the compensation method, the deviation of the pressure gap control was within 2%. [ABSTRACT FROM AUTHOR]

To overcome the issue of overheating and conserve cooling energy consumption, a superamphiphobic passive sub-ambient daytime radiative cooling (PSDRC) coating was extensively applied to distributed telecommunication base stations. The top surfaces of the battery and equipment cabinets coated with the PSDRC coating indicated prominent sub-ambient cooling effects regardless of the climate; this resulted in substantially lower surface temperatures compared with their counterparts. The applications of the PSDRC coating reduced the chamber interior temperature of an equipment cabinet by 10.4 °C during noon hours and by 6.0 °C before sunrise. The PSDRC-coated base stations could properly operate without air conditioners by replacing the closed door with a modified one containing an external exhaust system. The drastic decrease in the chamber interior temperature of the PSDRC base stations allowed them to conserve a considerable amount of cooling energy; this, resulted in cooling energy efficiencies between 31.7% and 64.9%. After more than one year, the surfaces of the PSDRC base station near busy city transit roads were still spotless and super non-wettable; this demonstrated the significance of the superamphiphobic self-cleaning topcoat and provided the top surfaces of the base stations in various regions with identical sub-ambient cooling effects on the initial state. • A passive subambient daytime radiative cooling (PSDRC) coating was prepared. • The PSDRC coating was superamphiphobic self-cleaning. • The PSDRC coating was used to distributed telecommunication base stations (TBSs). • The top surface of the PSDRC TBSs constantly showed subambient daytime cooling. • The cooling energy efficiency of the PSDRC TBSs was between 31.7% and 63.9%. [ABSTRACT FROM AUTHOR]

• A passive subambient daytime radiative cooling (PSDRC) coating was prepared. • The superamphiphobic topcoat had contact angles > 150° and sliding angles < 10°. • The different PSDRC roofs showed subambient cooling effects under direct sunlight. • The net energy reduction of the PSDRC-coated buildings was impressive. • The solar reflectance of the coating was reduced by 0.005 after dirt-resistance tests. • The solar reflectance of the coating was reduced by 0.021 after accelerated aging tests. In this study, a super-amphiphobic passive sub-ambient daytime radiative cooling (PSDRC) coating was applied to various buildings in different climatic regions in China. Irrespective of sunny, cloudy, and rainy weather conditions, the roof and west-facing wall surfaces coated with the PSDRC coating exhibited distinct sub-ambient cooling effects. Compared with the cool-white and grey roof surface temperatures, the roof surface temperature due to PSDRC coating was lower by 10.1 °C and 33.1 °C, respectively. Consequently, the room interior temperatures of different buildings were lower than the ambient air temperature during the day because of heat conduction and convection. The room with a window coated by the PSDRC coating had 18.2 °C lower interior temperature than that with a west-facing glass window. Thus, the PSDRC coating decreased the cooling energy consumption of buildings in the summer but increased the heating energy consumption in the winter. However, the net energy savings were considerable because of low solar irradiance and high heating energy demand when the sub-ambient cooling effect was diminished, which minimised the difference between the roof surface and room interior temperatures of the PSDRC and control buildings. After five-cycle dirt resistance tests, the solar reflectance of the super-amphiphobic PSDRC coating was reduced only by 0.0051. After 2000 h of artificial accelerated weathering tests, the solar reflectance of the superamphiphobic PSDRC coating was attenuated by 0.021 on average. This indicates the significance of the super-amphiphobic self-cleaning capability, which endowed the coating with a long-term sub-ambient cooling effect. [ABSTRACT FROM AUTHOR]

The composition and the preparation process of a bi-functional cool white roof coating based on styrene acrylate copolymer and cement that integrates both a good cooling effect and good mechanical properties and water impermeability are introduced. Its optical properties, cooling effect and relevant properties after dirt and accelerated exposures are systematically explored. Compared with the conventional polymer-modified cement-based waterproof coating, the cool white roof coating based on styrene acrylate copolymer and cement has a much higher solar reflectance due to the presence of the titanium dioxide rutile and Altiris 800, and it can significantly reduce the coating surface temperature. The sticky nature of the high elastic styrene acrylate copolymer emulsion makes it easy for the cool white roof coating based on styrene acrylate copolymer and cement to collect pollutants and thus endows the coating with moderate dirt resistance. Four hundred hours of artificial accelerated weathering decreases the solar reflectance of the cool white roof coating based on styrene acrylate copolymer and cement and the cooling effect of the coating. The artificial accelerated weather resistance of the cool white roof coating based on styrene acrylate copolymer and cement is qualitatively good. [ABSTRACT FROM AUTHOR]

The mechanical properties and water impermeability of the developed cool white roof coating based on styrene acrylic copolymer and cement are systematically investigated in the current paper. The coating has good tensile properties, adhesion strength and compliance at low temperature. In particular, the coating possesses excellent water impermeability. The good flexibility and compliance at low temperature result from the low glass transition temperature of the high elastic styrene acrylate copolymer emulsion. Compared with the untreated specimens, after thermal, alkali, water immersion and ultraviolet treatments, the tensile strength of the coating is increased, while its breaking elongation is decreased. In addition, the coating has good artificial accelerated weather resistance in terms of mechanical properties. The excellent water impermeability of the coating stem from the cross-linked nature of the high elastic styrene acrylate copolymer emulsion, the formation of interpenetrating network structures and the Ca 2+ bridging effect. [ABSTRACT FROM AUTHOR]

Abstract: The physicochemical properties of two newly developed dirt-resistant cool white coatings were systematically measured in light of the relevant standard testing methods, and the influences of dirt accumulation and washing on the long-term cooling performance of cool coatings were investigated and discussed. Both cool white coatings owe their outstanding physicochemical properties to the optimized formulations, high glass transition temperature and minimum film formation temperature of selected aqueous self-curing acrylic emulsions. The high solid content was also influential. Dirt accumulation leads to a decline in the cooling performance of coatings, which may be almost fully restored by simply washing the coatings with a mild soap solution. [Copyright &y& Elsevier]