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A fault diagnosis method for rolling element bearings based on ICEEMDAN and Bayesian network
Zengkai Liu,Kanglei Lv,Chao Zheng,Baoping Cai,Gang Lei,Yonghong Liu 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.5
As commonly used components in rotating machinery, rolling element bearings (REBs) can fail due to complex working conditions and high-speed rotation. The failure of bearings may cause great damage. It is necessary to identify the faults of bearings to prevent property losses and heavy casualties. This paper proposes a fault diagnosis approach based on improved complete ensemble empirical mode decomposition with adaptive noise (ICEEMDAN) and Bayesian network. The intrinsic mode functions (IMFs) extracted by ICEEMDAN algorithm are applied to construct feature vectors based on the energy entropy, and then the fault diagnosis model of the bearing is constructed by Bayesian network. The influence of load and sampling frequency on diagnostic accuracy of the bearing with different fault types is studied in this paper. And the research results show that the ICEEMDAN-BN method can improve the uncertainty reasoning ability and accuracy of the developed fault diagnosis model.
Prolonged antimicrobial activity of silver core-carbon shell nanoparticles
Zengkai Wang,Tianke Wang,An Hua,Song Ma,Zhidong Zhang,Lei Liu 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.11
Ag nanoparticles present good antimicrobial activity but with a potential toxicity to the cell, which limits the application. To address this issue, in this work, carbon-encapsulated sliver nanocapsules (Ag@C nanocapsules) were prepared by evaporating pure Ag ingot with the modified arc-discharge technique, and the Ag@C nanocapsules were acidified with nitric acid subsequently to facilitate the silver ion to release. Finally, Ag@C nanocapsules displayed a good and sustained antimicrobial activity against E. coli as a model of Gram-negative bacteria, due to the long-term release of sliver ions from Ag@C nanocapsules. The results obtained in this work indicate that the Ag@C nanocapsules may be a suitable nanomaterial for the bactericidal application.
Effect of molecular weight of regenerated silk fibroin on silk-based spheres for drug delivery
Zengkai Wang,Xiangming Li,Yanhua Cui,Kai Cheng,Mingdong Dong,Lei Liu 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.10
Silk fibroin presents a good advantage as a drug carrier for drug delivery, due to the excellent biocompatibility, biodegradability and tunable drug loading and release properties. In this work, we constructed silk spheres by phase separation of the regenerated silk fibroin (RSF) solutions with different MW and polyvinyl alcohol; and it was revealed that MW of RSF can affect the structure, size, surface potential and drug loading and release efficiency of silk spheres. Silk spheres prepared from high MW of RSF were found to load more macromolecular drug with negative charge compared to middle and low MW of RSF. However, for the positive charge and low MW drug, the silk spheres prepared from low MW of RSF could present a high loading efficiency compared to other carriers. Finally, a positive drug with low MW, streptomycin was encapsulated in silk spheres prepared from low MW of RSF, and displayed a long bactericidal and bacteriostatic effect compared to bared streptomycin solution. The results obtained provide guidelines for the modification and options of drug transport vehicles for more efficient drug delivery and utilization through a simple, rapidly constructed, applicable and low-cost drug carrier.