In this paper, cross-linked polyethylene (XLPE) cables of the same batch from Factory A, which ran from 1 to 8 years in Jiangsu Province, are sampled. Some widely accepted aging characterization methods of XLPE cables such as the gel content test, differential scanning calorimetry (DSC) test, tensile test and hardness test are employed to obtain the physicochemical, mechanical and electrical properties of the samples. Then, some lifespan prediction parameters significantly correlated with operating time are obtained through correlation calculations. Finally, a prediction method is proposed to predict the operating time of XLPE cables from Factory A. The test results indicate that parameters including the gel content Cge, the crystallinity XC, tensile strength σ, ultimate elongation δ, the dielectric permittivity ε, and the dielectric loss Jtan are significantly correlated with operating time, which can be used in evaluating the aging degree of XLPE cables. Moreover, due to the high accuracy of the experimental verification, it turns out that the lifespan prediction method proposed in this paper can be used to determine the operating time of XLPE cables from Factory A in future research.

Cross‐linked polyethylene (XLPE) cables are a critical component of power transmission systems. As operating conditions sometimes exceed the thresholds set in discipline, some cables fail to reach their designed lifespan, and consequently evaluating the aging degree of cables is particularly necessary. Here ten cables with an operating duration between 1 and 11 years from adjacent lines were sampled. Investigations were performed through various aging evaluation methods. Then typical lifespan prediction indices were concluded from test results and filtrated through correlation calculation. Meanwhile, a lifespan prediction method based on GM (1, N) model was proposed to establish the equivalent relationship between operating time and these indices. The research results indicated that, lifespan prediction indices obtained were all significantly correlated with operating time, which can be used to characterize aging degree of XLPE cables. Besides, due to the high prediction accuracy of experimental verification, the GM (1, N) model was proved to be applicable to evaluate the aging degree quantitatively and determine the remaining lifespan (relative to the designed lifespan) of XLPE cables. In future research, this method can be used to formulate a reasonable and economic withdrawal strategy for XLPE cables operating in conditions that exceed the thresholds set in the discipline.

The Na2SnO3 and H-N-R inhibitors effects on the high active aluminum alloy in alkaline solution (805mol/LNaOH) have been systematically studied by hydrogen collection and electrochemical measurement in the present investigation. The results showed that the hydrogen evolution rate was low at the value of 0.404 mL/ (min·cm2) in alkaline solution with 0.01mol/L Na2SnO3, but the electrode potential was only -1.515Vvs.SCE and it moved to the positive direction seriously; When adding 10wtH-N-R and 0.01mol/LNa2SnO3 into the alkaline solution simultaneously, the aluminum alloy anode had a lower hydrogen evolution rate of 0.342mL/ (min·cm2) and a more negative electrode potential of -1.591Vvs.SCE. The electrochemical performance of aluminum alloy anode has been improved greatly by the cooperation of H-N-R and Na2SnO3.

Zirconia-mullite nanocomoposites were prepared from Si-Al-Zr-O amorphous bulk with diffrent content of CaO and MgO by two-step thermal treatment between 900 and 1200°C. The effects of the additives on the phase and microsturcture were studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The results show that the addition of CaO promotes cristobalite phase formation and the anisotropic growth of mullite grains. An indention micro-crack method was used to measure the fracture toughness of zirconia-mullite nanocomoposites. The results demonstrate that the fracture toughness increases with higher concentration of CaO. The improvement of fracture toughness is attributed to the anisotropic growth of grains.

Zirconia-mullite nanocomoposites were prepared from TiO2-doped Si-Al-Zr-O amorphous bulks according to a two-step heating treatment between 880 and 1250°C. Effects of TiO2 amount and heat treatment conditions on the mechanical properties have been investigated. The fracture toughness was much more affected by the heat treatment processing than by amount of TiO2. With increasing amount of TiO2 (2.5~10 wt %), the fracture toughness gradually decreases. Nucleating temperature and time and crystallization temperature and time are interrelated. The fracture toughness of the sample with 5 wt% TiO2 nucleated at 920°Cfor 2.0 h and crystallized 1150°Cfor 4.0 h is 7.48 MPa•m1/2.