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When insulation defects arise in cables， they trigger the occurrence of sub-cycle disturbance voltage， making it imperative to extract the disturbance voltage features for timely defect detection and ensuring safe operation. To address this need， a method for extracting cable sub-cycle disturbance voltage features is introduced. Firstly， the cable’s sub-cycle disturbance voltage waveform is obtained through testing， and two characteristic parameters， namely time and amplitude， are defined for the disturbance waveform. Subsequently， voltage amplitude changes are rapidly tracked using the strong tracking Kalman filter （STKF）. Adaptive parameters are established to suppress fluctuations in the parameters of the Gaussian mixture model （GMM）， facilitating the extraction of disturbance voltage characteristic parameters through the combined use of STKF and GMM. The algorithm is then tested using disturbance voltage data obtained from experiments， and the effects of adaptive parameters， sampling frequency， and the detection algorithm’s dead zone within the Gaussian mixture model on the extraction of characteristic parameters are analyzed. MATLAB simulation results demonstrate that the computational outcomes remain relatively stable when the voltage sampling frequency is set at 2.25 kHz and above. This validation underscores the method’s capability to extract characteristic parameters related to cable sub-cycle disturbance voltage.

The method of fast non-destructive testing for aluminium sheaths of high-voltage (HV) cables using ultrasonic-guided waves is proposed. The dispersion curve is calculated by solving the dispersion equation from the simplified model of aluminium sheaths of HV cables; thus, the appropriate wave mode and excitation frequency can be chosen. Three defects including crack, perforation, and sag have been set up. Then, the simulation experiments have been carried out for aluminium sheaths of HV cables based on the theoretical analysis and finite element simulation. The results show that cracks with the loss ratio of the sectional area over 4.25% can be detected by the T (0, 1) mode whose frequency is 32 kHz; the amplitude of the flaw echo increases along with the loss ratio of the crack. Theoretical analysis, finite element simulation, and experiments prove the feasibility of aluminium sheaths using ultrasonic-guided waves, providing a new method for the defect testing.

The interior of a high-voltage cable causes a state of extrusion due to thermomechanical effects; the resulting stress and deformation can easily lead to the destruction of the cable structure. Aiming at the problem, we establish an electromagnetic–thermal–force field model of a high voltage cable. By considering the influence of temperature on the material properties, a bidirectional couple simulation of electromagnetic and thermal fields is established. The thermal load excitation is introduced into the structural field, and the simulation calculation of thermal strain and thermal stress of the axial and radial layers is realized. The influence of ambient temperature, load current, and circulating current defect factors on the thermal–force characteristics of each layer of the cable is studied. The results show that the response of the insulating layer to the thermomechanical effect is the most significant, and its characteristic change law shows the nonlinear trend. In addition, the thermal strain of the cable has an approximate axial symmetry; the axial thermomechanical effect is significantly higher than the radial direction. The maximum axial and radial deformations of the cable when running at full load are 1.21 and 0.16 mm respectively. Among the three influencing factors, the impact of circulating current defects on the thermomechanical effect of cables is the most obvious. The thermomechanical effect of the cable approximately is positively related to the square of the circulating current defect factors, the load current, and the ambient temperature. [ABSTRACT FROM AUTHOR]

Electrolytic active water was prepared by electrolytic treatment of sodium chloride aqueous solution using a self-made device. In order to investigate the properties of electrolytic active water, the pH value, available chlorine contents and decolorization ability on methylene blue solution were tested and compared with that of sodium hypochlorite aqueous solution. Experimental results showed that the electrolytic active water has higher oxidation capacity and decolorization efficiency for methylene blue compared with sodium hypochlorite solution, implying maybe other reactive oxygen species components besides hypochlorite existed in the electrolytic active water. The electrolytic active water was stable under long-term storage, and mechanical force with oxidation activity did not decrease. In addition, the decolorization kinetics of methylene blue in the electrolytic active water was explored, and it was found that, in general, the decolorization reaction of methylene blue in electrolytic active water was consistent with the first-order reaction kinetics model, but when the pH value of electrolytic active water solution was weakly alkaline or neutral, the decolorization reaction of methylene blue was closer to the second-order reaction kinetics model. [ABSTRACT FROM AUTHOR]

Background: Migraine is a debilitating neurological disorder involving abnormal trigeminovascular activation and sensitization. However, the underlying cellular and molecular mechanisms remain unclear. Methods: A rat model of conscious migraine was established through the electrical stimulation (ES) of the dural mater surrounding the superior sagittal sinus. Using patch clamp recording, immunofluorescent labelling, enzyme-linked immunosorbent assays and western blot analysis, we studied the effects of ES on sensory neuronal excitability and elucidated the underlying mechanisms mediated by voltage-gated ion channels. Results: The calcitonin gene-related peptide (CGRP) level in the jugular vein blood and the number of CGRP-positive neurons in the trigeminal ganglia (TGs) were significantly increased in rats with ES-induced migraine. The application of ES increased actional potential firing in both small-sized IB4-negative (IB4−) and IB4+ TG neurons. No significant changes in voltage-gated Na+ currents were observed in the ES-treated groups. ES robustly suppressed the transient outward K+ current (IA) in both types of TG neurons, while the delayed rectifier K+ current remained unchanged. Immunoblot analysis revealed that the protein expression of Kv4.3 was significantly decreased in the ES-treated groups, while Kv1.4 remained unaffected. Interestingly, ES increased the P/Q-type and T-type Ca2+ currents in small-sized IB4− TG neurons, while there were no significant changes in the IB4+ subpopulation of neurons. Conclusion: These results suggest that ES decreases the IA in small-sized TG neurons and increases P/Q- and T-type Ca2+ currents in the IB4− subpopulation of TG neurons, which might contribute to neuronal hyperexcitability in a rat model of ES-induced migraine. [ABSTRACT FROM AUTHOR]

Abstract: Glial cell line-derived neurotrophic factor (GDNF) is a potent protective factor for dopaminergic (DA) neurons, but the signaling mechanisms underlying the effect of GDNF on these neurons remain obscure. Here, both our in vivo and in vitro studies demonstrate that the majority of DA neurons express the NF-κB-inducing kinase (NIK), which is the essential kinase for mediating activation of the new alternative NF-κB signaling pathway. Additionally, we also show that GDNF induced the time/dose-dependent phosphorylation of IκB kinase α (IKKα) and p100, facilitated the processing of p100 to p52 and accelerated the translocation of NF-κB dimmers into the nuclei of DA neurons. We furtherly found that the dimmer which translocate into the nucleus was RelA/p52 not RelB/p52. Meanwhile, the attenuation of 6-OHDA-induced DA neuronal apoptosis due to GDNF was reversed subsequent to the inhibition of p100 expression by RNAi while the neuroprotective effect of GDNF on injured DA neurons was strengthened by the overexpression of p100. Our data, therefore, indicate that a new alternative NF-κB signaling pathway, which was not the classic pathway but different from the non-canonical pathway, exists in DA neurons and mediates the neuroprotective effect of GDNF on these neurons. [Copyright &y& Elsevier]