Transient and Steady-State Deformations of a Vesicle with an Insulating Membrane in Response to Step-Function or Alternating Electric Fields

Trimethylolpropane triacrylate (TMPTA) as a photoactive crosslinker is grafted onto hydrophobic nanosilica surface through click chemical reactions of mercapto double bonds to prepare the functionalized nanoparticles (TMPTA-s-SiO2), which are used to develop TMPTA-s-SiO2/XLPE nanocomposites with improvements in mechanical strength and electrical resistance. The expedited aging experiments of water-tree growth are performed with a water-knife electrode and analyzed in consistence with the mechanical performances evaluated by means of dynamic thermo-mechanical analysis (DMA) and tensile stress–strain characteristics. Due to the dense cross-linking network of polyethylene molecular chains formed on the TMPTA-modified surfaces of SiO2 nanofillers, TMPTA-s-SiO2 nanofillers are chemically introduced into XLPE matrix to acquire higher crosslinking degree and connection strength in the amorphous regions between polyethylene lamellae, accounting for the higher water-tree resistance and ameliorated mechanical performances, compared with pure XLPE and neat-SiO2/XLPE nanocomposite. Hydrophilic TMPTA molecules grafted on the nano-SiO2 surface can inhibit the condensation of water molecules into water micro-beads at insulation defects, thus attenuating the damage of water micro-beads to polyethylene configurations under alternating electric fields and thus restricting water-tree growth in amorphous regions. The intensified interfaces between TMPTA-s-SiO2 nanofillers and XLPE matrix limit the segment motions of polyethylene molecular chains and resist the diffusion of water molecules in XLPE amorphous regions, which further contributes to the excellent water-tree resistance of TMPTA-s-SiO2/XLPE nanocomposites.

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Establishment of a New Device for Electrical Stimulation of Non-Degenerative Cartilage Cells In Vitro

International Journal of Molecular Sciences ◽

10.3390/ijms22010394 ◽

2021 ◽

Vol 22 (1) ◽

pp. 394

Author(s):

Simone Krueger ◽

Alexander Riess ◽

Anika Jonitz-Heincke ◽

Alina Weizel ◽

Anika Seyfarth ◽

...

Keyword(s):

Electrical Stimulation ◽

Electric Fields ◽

Cartilage Tissue ◽

Type I ◽

Dependent Manner ◽

New Device ◽

Alternating Electric Fields ◽

Cartilage Cells ◽

Stimulation Of

In cell-based therapies for cartilage lesions, the main problem is still the formation of fibrous cartilage, caused by underlying de-differentiation processes ex vivo. Biophysical stimulation is a promising approach to optimize cell-based procedures and to adapt them more closely to physiological conditions. The occurrence of mechano-electrical transduction phenomena within cartilage tissue is physiological and based on streaming and diffusion potentials. The application of exogenous electric fields can be used to mimic endogenous fields and, thus, support the differentiation of chondrocytes in vitro. For this purpose, we have developed a new device for electrical stimulation of chondrocytes, which operates on the basis of capacitive coupling of alternating electric fields. The reusable and sterilizable stimulation device allows the simultaneous use of 12 cavities with independently applicable fields using only one main supply. The first parameter settings for the stimulation of human non-degenerative chondrocytes, seeded on collagen type I elastin-based scaffolds, were derived from numerical electric field simulations. Our first results suggest that applied alternating electric fields induce chondrogenic re-differentiation at the gene and especially at the protein level of human de-differentiated chondrocytes in a frequency-dependent manner. In future studies, further parameter optimizations will be performed to improve the differentiation capacity of human cartilage cells.

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Robust fault‐tolerant consensus control for nonlinear multi‐agent systems with prescribed transient and steady‐state performance

Asian Journal of Control ◽

10.1002/asjc.2544 ◽

2021 ◽

Author(s):

Yunbiao Jiang ◽

Zhongxin Liu ◽

Zengqiang Chen

Keyword(s):

Steady State ◽

Fault Tolerant ◽

Multi Agent Systems ◽

Consensus Control ◽

Agent Systems ◽

Multi Agent ◽

Transient And Steady State ◽

Steady State Performance

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Modeling of assembly systems with complex structures for throughput analysis during transients

Assembly Automation ◽

10.1108/aa-12-2017-172 ◽

2019 ◽

Vol 39 (2) ◽

pp. 262-271

Author(s):

Yukan Hou ◽

Yuan Li ◽

Yuntian Ge ◽

Jie Zhang ◽

Shoushan Jiang

Keyword(s):

Steady State ◽

Fixed Point Theory ◽

Point Theory ◽

Assembly Systems ◽

Complex Structures ◽

Throughput Performance ◽

Throughput Analysis ◽

Content Type ◽

Serial Production Lines ◽

Transient And Steady State

Purpose The purpose of this paper is to present an analytical method for throughput analysis of assembly systems with complex structures during transients. Design/methodology/approach Among the existing studies on the performance evaluation of assembly systems, most focus on the system performance in steady state. Inspired by the transient analysis of serial production lines, the state transition matrix is derived considering the characteristics of merging structure in assembly systems. The system behavior during transients is described by an ergodic Markov chain, with the states being the occupancy of all buffers. The dynamic model for the throughput analysis is solved using the fixed-point theory. Findings This method can be used to predict and evaluate the throughput performance of assembly systems in both transient and steady state. By comparing the model calculation results with the simulation results, this method is proved to be accurate. Originality/value This proposed modeling method can depict the throughput performance of assembly systems in both transient and steady state, whereas most exiting methods can be used for only steady-state analysis. In addition, this method shows the potential for the analysis of complex structured assembly systems owing to the low computational complexity.

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