Fractional-order identification and synthesis of equivalent circuit for electrochemical system based on pulse voltammetry

In order to improve the battery management system performance and enhance the adaptability of the system, a fractional order equivalent circuit model of lithium-ion battery based on electrochemical test was established. The parameters of the fractional order equivalent circuit model are identified by the least squares parameter identification method. The least squares parameter identification method needs to rely on the harsh test conditions of the laboratory, and the parameter identification result is static; it cannot adapt to the characteristics of the lithium battery under dynamic conditions. Taking into account the dynamic changes of lithium batteries, a parameter adaptive online estimation algorithm for fractional equivalent circuit model is proposed. Based on the theory of fractional order calculus and indirect Lyapunov method, the stability and convergence of the estimator are analyzed. Finally, simulation experiments show that this method can continuously estimate the parameters of the fractional order equivalent circuit under UDDS conditions.

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Development and Evaluation of Copper Electrodes, Modified with Bimetallic Nanoparticles, to be Used as Sensors of Cysteine-Rich Peptides Synthesized by Tobacco Cells Exposed to Cytotoxic Levels of Cadmium

Molecules ◽

10.3390/molecules24122200 ◽

2019 ◽

Vol 24 (12) ◽

pp. 2200

Author(s):

Carlos Velasco-Medina ◽

Patricio J. Espinoza-Montero ◽

Marjorie Montero-Jimenez ◽

José Alvarado ◽

Mónica Jadán ◽

...

Keyword(s):

Nicotiana Tabacum ◽

Electrochemical Sensors ◽

Bimetallic Nanoparticles ◽

Differential Pulse ◽

Electrochemical System ◽

Complex Matrix ◽

Bimetallic Particles ◽

Copper Electrodes ◽

Pulse Voltammetry

We report on two new electrochemical sensors which, coupled to differential pulse voltammetry, constitutes a useful tool for diagnosis of heavy metal pollution. The electrochemical sensors AgHgNf/Cu and the AgBiNf/Cu were obtained by deposition of bimetallic particles of AgHg or AgBi on copper electrodes covered with a Nafion (Nf) film, respectively. Micrographs of the electrode’s surface showed evenly scattered bimetallic particles, with an approximate diameter of 150 nm, embedded in the Nafion (Nf) film. In order to test the electrodes, the hydrogen evolution signal according to the Brdička reaction was measured for the determination of cysteine-rich peptides (CRp) produced by plants. To check the accuracy of the electrodes, real samples of Nicotiana tabacum cells exposed to cytotoxic levels of cadmium were tested. The AgHgNf/Cu electrode produced detection limits (DLs) of 0.088 µmol L−1 for Cysteine and 0.139µmol L−1 for Glutathione, while for the AgBiNf/Cu electrode DLs were 0.41 µmol L−1 for cysteine and 0.244 µmol L−1 for glutathione. Thus, the new electrodes could be a useful analytical electrochemical system very convenient for fieldwork. The electrodes were capable of direct, accurate, and sensitive detection of synthesized peptides, despite the complex matrix where the Nicotiana tabacum cells were grown.

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Modelling of ultracapacitor using a fractional-order equivalent circuit

International Journal of Renewable Energy Technology ◽

10.1504/ijret.2015.068595 ◽

2015 ◽

Vol 6 (2) ◽

pp. 142 ◽

Cited By ~ 5

Author(s):

Nafisah Naim ◽

Dino Isa ◽

Roselina Arelhi

Keyword(s):

Equivalent Circuit ◽

Fractional Order

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A Comparative Study of Two Fractional-Order Equivalent Electrical Circuits for Modeling the Electrical Impedance of Dental Tissues

Entropy ◽

10.3390/e22101117 ◽

2020 ◽

Vol 22 (10) ◽

pp. 1117 ◽

Cited By ~ 1

Author(s):

Norbert Herencsar ◽

Todd J. Freeborn ◽

Aslihan Kartci ◽

Oguzhan Cicekoglu

Keyword(s):

Equivalent Circuit ◽

Fractional Order ◽

Biological Tissue ◽

Electrical Impedance ◽

Model Parameters ◽

Dental Tissue ◽

Tissue Impedance ◽

Dental Tissues ◽

Impedance Models ◽

Equivalent Circuit Models

Background: Electrical impedance spectroscopy (EIS) is a fast, non-invasive, and safe approach for electrical impedance measurement of biomedical tissues. Applied to dental research, EIS has been used to detect tooth cracks and caries with higher accuracy than visual or radiographic methods. Recent studies have reported age-related differences in human dental tissue impedance and utilized fractional-order equivalent circuit model parameters to represent these measurements. Objective: We aimed to highlight that fractional-order equivalent circuit models with different topologies (but same number of components) can equally well model the electrical impedance of dental tissues. Additionally, this work presents an equivalent circuit network that can be realized using Electronic Industries Alliance (EIA) standard compliant RC component values to emulate the electrical impedance characteristics of dental tissues. Results: To validate the results, the goodness of fits of electrical impedance models were evaluated visually and statistically in terms of relative error, mean absolute error (MAE), root mean squared error (RMSE), coefficient of determination (R2), Nash–Sutcliffe’s efficiency (NSE), Willmott’s index of agreement (WIA), or Legates’s coefficient of efficiency (LCE). The fit accuracy of proposed recurrent electrical impedance models for data representative of different age groups teeth dentin supports that both models can represent the same impedance data near perfectly. Significance: With the continued exploration of fractional-order equivalent circuit models to represent biological tissue data, it is important to investigate which models and model parameters are most closely associated with clinically relevant markers and physiological structures of the tissues/materials being measured and not just “fit” with experimental data. This exploration highlights that two different fractional-order models can fit experimental dental tissue data equally well, which should be considered during studies aimed at investigating different topologies to represent biological tissue impedance and their interpretation.

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