Abstract In this research, a firing test was conducted on a Hybrid Rocket Motor (HRM) that operates using an aluminized solid propellant containing HMX and Hydrogen Peroxide (HP). The instantaneous regression rate of HRM is determined using reconstruction techniques, and the formula of regression rate is fitted by reconstruction techniques and traditional weight-loss method. The utilization of the reconstruction method presents a notable advantage, as it allows for the determination of the regression rate’s sensitivity to variations in oxidizer mass flux. Additionally, this method enables the fitting of the regression rate formula based on data obtained from a single firing test. The average value of regression rate of four times firing test are 0.944, 0.529, 0.595 and 0.486 mm/s. According to the weight-loss method and reconstruction techniques, the coefficients of determination ( R 2 ) of regression rate formula fitting are 0.8867 and 0.93 respectively, indicating that the accuracy of the fitting is better than that of traditional method. Overall, this paper presents a comparison of traditional weight-loss method and reconstruction techniques for providing a critical preference for the research of regression rate of HRM.
At present, with the deep integration of advanced information and communication technologies such as artificial intelligence, big data, and the Internet of Things and power technology, compared with the traditional power grid, the new power system is more multi-source heterogeneous, open and ubiquitous, and its attack surface is greatly expanded, the difficulty of security protection has increased sharply, and it is urgent to improve the security construction of the power information system. Compliance inspection and security assessment are important ways to guide the security construction of power information systems to this end, this paper is in-depth understanding of the current status of the network security of the power information system, combined with the network security classified protection system 2.0. A comprehensive evaluation method of power information system security protection based on entropy weight-TOPSIS algorithm is proposed, and through model case analysis, it provides an important theoretical basis for the safe, reliable and standardized development of power system.
Steel rebars are widely applied in reinforced concrete structures due to their contribution to significant improvements in mechanical properties. However, exposure to corrosive environments, such as solution-containing chloride, may induce an accelerated corrosion and jeopardize the sustainability and durability of reinforced concrete. The current work evaluated the chloride thresholds (in both wt% and [Cl−]/[OH−]) of steel rebar with different chromium contents (0 wt%, 4 wt%, and 23 wt%) in synthetic concrete pore solution based on AC and DC electrochemical measurements, and chemical and structural characterizations. The study found that the chloride threshold (CT) values varied slightly based on the different measurement methods and the values were compared with values obtained from the literature. The values are 0.01 wt% to 0.1 wt% (3.76), 0.1 wt% to 1 wt% (>23.8), and 2.9 wt% to 3.5 wt% (>23.8) for 615, 4% Cr, and SS23, respectively, where the values in parentheses are [Cl−]/[OH−]. Therefore, it is demonstrated that multiple measurements are necessary to determine a reliable CT value. Corrosion mechanisms giving rise to CT are included to illustrate the processes involved in establishing CT.
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